蜡质玉米淀粉的凝胶化性质及其在陶瓷凝固成型中的应用研究

本文对蜡质玉米淀粉的糊性质、流变特性和凝胶强度等凝胶化性质进行了详细研究。结果表明:与普通玉米淀粉相比,蜡质玉米淀粉易糊化,热粘稳定性差,冷粘稳定性好,凝胶强度低;蜡质玉米淀粉糊属假塑性流体,且糊的表观粘度受淀粉浓度、温度和pH值的影响。利用蜡质玉米淀粉的凝胶化性质可实现Al2O3陶瓷的原位固化成型,且成型的陶瓷坯体外观光洁、平整、无缺陷,坯体的密度高、线收缩率低。

几种木薯变性淀粉凝胶化性质的研究

对木薯醋酸酯淀粉、磷酸酯淀粉和氧化淀粉的糊化性质、流变特性和凝胶强度等凝胶化性质进行了比较研究。研究表明:醋酸酯淀粉和磷酸酯淀粉的糊化温度与原淀粉相当,氧化淀粉的糊化温度降低。醋酸酯淀粉和磷酸酯淀粉糊具有剪切稀化特性,属假塑性流体,氧化淀粉糊呈牛顿流体的特征。3种变性淀粉糊的表观粘度受浓度、温度和pH值的影响,与木薯原淀粉相比,变性淀粉糊具有较好的耐热和耐酸碱稳定性。而凝胶强度因变性基团的不同,差异较大。

淀粉的热性质在贝母类药材鉴别和分类中的应用

目的研究不同贝母药材中淀粉的凝胶化性质及其差异,为贝母类中药材的鉴别提供大分子方面的佐证。方法采用差示扫描量热仪对9种贝母类药材中的淀粉进行热性质测试,获得了9种贝母淀粉的DSC谱图以及凝胶化数据。结果通过对贝母中淀粉的凝胶化性质进行比较发现,浙贝母和湖北贝母中淀粉的凝胶化性质较为接近,青贝母,松贝母和炉贝母淀粉的凝胶化性质较为接近,岷贝母淀粉的凝胶化性质却与前三者有着明显的差别,而新疆贝母和伊犁贝母淀粉的凝胶化性质存在明显的差异。结论根据贝母淀粉凝胶化性质的特征,可以很容易对贝母类中药材进行分类和鉴别。

Effects of P2Y_1 receptor on glial fibrillary acidic protein and glial cell line-derived neurotrophic factor production of astrocytes under ischemic condition and the related signaling pathways

Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein （GFAP） production and glial cell line-derived neurotrophic factor （GDNF） secretion of astrocytes under ischemic insult and the related signaling pathways. Methods Using transient right middle cerebral artery occlusion （tMCAO） and oxygen-glucose-serum deprivation for 2 h as the model of ischemic injury in vivo and in vitro, immunofluorescence, quantitative real-time reverse transcription-polymerase chain reaction （RT-PCR）, Western blotting, enzyme linked immunosorbent assay （ELISA） were used to investigate location of P2Y1 receptor and GDNF, the expression of GFAP and GDNF, and the changes of signaling molecules. Results Blockage of P2Y1 receptor with the selective antagonist N^6-methyl-2′-deoxyadenosine 3′,5′-bisphosphate diammonium （MRS2179） reduced GFAP production and increased GDNF production in the antagonist group as compared with simple ischemic group both in vivo and in vitro. Oxygen-glucose-serum deprivation and blockage of P2Y1 receptor caused elevation of phosphorylated Akt and cAMP response element binding protein （CREB）, and reduction of phosphorylated Janus kinase2 （JAK2） and signal transducer and activator of transcription3 （STAT3, Ser727）. After blockage of P2Y1 receptor and deprivation of oxygen-glucose-serum, AG490 （inhibitor of JAK2） reduced phosphorylation of STAT3 （Ser727） as well as expression of GFAP; LY294002, an inhibitor of phosphatidylinositol 3-kinase （PI3-K）, decreased phosphorylation of Akt and CREB; the inhibitor of mitogen-activated protein kinase kinase 1/2 （MEK 1/2） U0126, an important molecule of Ras/extracellular signal- regulated kinase （ERK） signaling pathway, decreased the phosphorylation of JAK2, STAT3 （Ser727）, Akt and CREB. Conclusion These results suggest that P2Y1 receptor plays a role in the production of GFAP and GDNF in astrocytes under transient ischemic condition and the related signaling pathways may be JAK2/STAT3 and PI3-K/Akt/CREB, respectively, and that crosstalk probably exists between them.

Study on Properties of Composite Oxides TiO_2/SiO_2

The nanometer particles of TiO_2 and TiO_2/SiO_2 oxides wereprepared by sol-gel supercritical fluid drying method. The propertiesof TiO_2 and TiO_2/SiO_2 were characterized by means of BET(Brunner-Emmett- Teller method), TEM (transmission electronmicroscopy), SEM (scanning electron microscopy), XRD (X-ray diffrac-tion) and FTIR (Fourier transform-infrared) techniques. The effectsof different preparation route, prehydrolysis and non-prehydrolysis,on the properties of TiO_2/SiO_2 oxide were also examined.

A specific gene-expression signature quantifies the degree of hepatic fibrosis in patients with chronic liver disease

AIM： To study a more accurate quantification of hepatic fibrosis which would provide dinically useful information for monitoring the progression of chronic liver disease. METHODS： Using a cDNA microarray containing over 22000 clones, we analyzed the gene-expression profiles of non-cancerous liver in 74 patients who underwent hepatic resection. We calculated the ratio of azanstained： total area, and determined the morphologic fibrosis index （MFI）, as a mean of 9 section-images. We used the MFI as a reference standard to evaluate our method for assessing liver fibrosis. RESULTS： We identified 39 genes that collectively showed a good correlation （r 〉 0.50） between geneexpression and the severity of liver fibrosis. Many of the identified genes were involved in immune responses and cell signaling. To quantify the extent of liver fibrosis, we developed a new genetic fibrosis index （GFI） based on gene-expression profiling of 4 clones using a linear support vector regression analysis. This technique, based on a supervised learning analysis, correctly quantified the various degrees of fibrosis in both 74 training samples （r = 0.76, 2.2% vs 2.8%, P 〈 0.0001） and 12 independent additional test samples （r = 0.75, 9.8% vs 8.6%, P 〈 0.005）. It was far better in assessing liver fibrosis than blood markers such as prothrombin time （r = -0.53）, type IV collagen 7s （r = 0.48）, hyaluronic acid （r = 0.41）, and aspartate aminotransferase to platelets ratio index （APRI） （r = 0.38）. CONCLUSION： Our cDNA microarray-based strategy may help clinicians to precisely and objectively monitor the severity of liver fibrosis.

Science Letters; In-situ synthesis and luminescence properties of titanium oxide gels containing 1,10-phenanthroline europium(Ⅲ) complex

It is difficult to directly dope europium complexes in gel because the excessive water or high acidic condition may lead to their decomposition. We prepared a novel homogeneous TiO2 gel containing Eu-phen complexes by using an in-situ synthesis method. The formation of Eu-phen complexes in sol-gel derived TiO2 was confirmed by luminescence excitation spectra. The effects of temperature and aging time on in-situ synthesis are discussed. The luminescence spectra of gel containing europium complexes were also compared with the pure Eu-phen complexes.

Co-processing petroleum catalytic slurry with coal

It is studied that reactivity of petroleum catalytic slurry （PCS） and coal with Fe catalyst in 1 L autoclave, the fol- lowing is mainly discussed, coal conversion and asphalt properties, especially related with petroleum cracking slurry （PCS） properties. The results show that co-processing conversion and asphalt yield increase with the increase of PCS ratio. PCS prop- erties have important effect on coal conversion and asphalt properties. One kind of PCS shows negative effect on coal conver- sion. High aromatic PCS can lead to high ductility asphalt with good colloid properties. Coal and the PCS can lead to a strong matching effect.

Chemical characterization and composition of dissolved organic matter in Jiaozhou Bay

Biologically utilizable dissolved organic compounds,including dissolved organic carbon (DOC),dissolved carbohydrates (DCHO) and dissolved free amino acids (DFAA) were analyzed in filtered surface seawater samples collected at 19 stations in Jiaozhou Bay,China,on June 3,2007.In these samples,concentrations of DOC,dissolved free carbohydrates (DFCHO),dissolved combined carbohydrates (DCCHO),total dissolved carbohydrates (TDCHO) and total dissolved free amino acids (TDFAA) ranged from 141.7 to 191.1 μmol C/L,1.98 to 18.18 μmol C/L,5.04 to 24.90 μmol C/L,14.52 to 30.36 μmol C/L,and 1.83 to 11.89 μmol C/L,respectively.As a major component of the dissolved carbohydrates,the concentrations of DCCHO were about three times higher than those of DFCHO.Three major constituents of the DFAA were threonine (23.0±5.7 mol%),glutamic acid (16.6±3.2 mol%) and arginine (9.1±3.3 mol%).Based on the composition of DFAA,a molar C:N ratio of 3.60±0.75 in DFAA was derived,indicating longer carbon chains in the amino acids.DCCHO (8.1%) was the most abundant fraction of DOM in most samples,followed by DFCHO (4.8%) and TDFAA (2.7%).These DOM concentrations displayed a decreasing trend from the coast to the central region.Significant correlations were found between the DCCHO and DFCHO concentrations (r=-0.724,n=19,P<0.001) and the DCCHO and TDCHO concentrations (r=0.506,n=19,P=0.027).

Sol-Gel Synthesis and Structure-Property Relations in Nd4-xCs2（1＋x）Fe5-xZnxO14＋δ（0≤x≤1.0） Oxide Systems

Synthesis of composite oxides in the series Nd4-xCs2（1＋x）Fe5-xZnxO14＋δ（0≤x≤1.0） （B1-B5： x= 0.0, 0.25, 0.5, 0.75, 1.0） is performed by sol-gel method via nitrate-acetate precursor route. Analysis of the powder x-ray diffraction （XRD） patterns show tetragonal unit cell with lattice parameters a = 8.6545, 8.2520, 7.7645, 9.8952, 8.2863 A; b = 8.9800, 11.5788, 15.6305, 8.4766, 11.6465 A in B1-B5, respectively. The average crystallite sizes in the samples are found to be in the range 69.56-119.48 A. Energy dispersive analysis of x-rays （EDAX） result shows the presence of Fe, Nd, Cs and O, and Fe, Nd, Zn, Cs and O in B 1 （x=0） and B2（x=0.25）-B5（x= 1.0）, respectively. The IR results at 300 K show the presence of octahedral [NdO6/2]^3- （asymmetric stretch： 410-416 cml） and [FeO6/2]^3-（symmetric stretch： 562-572 cm^-1） units in the samples. Observed magnetic moments versus magnetic field plots in the range -10 kG to ＋10 kG exhibit hysteresis loops with average magnetic susceptibility values in the range 3.46 × 10^-5 -7.05 × 10^-5 emu/gG in B1-B5 shows fairly strong ferromagnetic nature of the samples. The observed EPR lineshapes at 300 and 77 K with giso=2.01-2.03 and giso=2.01-2.03, respectively is ascribed to the octahedral [FeO6/2]^3- coordination of Fe^3＋ （3d^5） ion. The optical absorption spectra show the transition of ^4I9/2→^4F7/2→^ 4S3/2 （750 nm） of optically active Nd^3＋ ions in samples.

Electron-Irradiation Induced Nanocrystallization of Pb（ll） in Silica Gels Prepared in High Magnetic Field

In a previous study, structure of silica gels prepared in a high magnetic field was investigated. While a direct application of such anisotropic silica gels is for an optical anisotropic medium possessing chemical resistance, we show here their possibility of medium in materials processing. In this direction, for example, silica hydrogels have so far been used as media of crystal growth. In this paper, as opposed to the soft-wet state, dried silica gels have been investigated. We have found that lead （II） nanocrystallites were formed induced by electron irradiation to lead （ll）-doped dried Hydrogels made from a sodium metasilicate solution doped with silica gels prepared in a high magnetic field such as B = 10 T. lead （II） acetate were prepared. The dried specimens were irradiated by electrons in a transmission electron microscope environment. Electron diffraction patterns indicated the crystallinity of lead （II） nanocrystallites depending on B. An advantage of this processing technique is that the crystallinity can be controlled through the strength of magnetic field B applied during gel preparation. Specific skills are not required to control the strength of magnetic field.

Clinicopathological and immunohistochemical features of pilomyxoid astrocytoma: a report of six cases

Objective： The aim of this study was to study the clinicopathological and immunohistochemical features of pilo- myxoid astrocytoma （PMA）. Methods： The clinical and pathologic features in six cases of PMA were analyzed. Immunohisto- chemical staining for glial fibrillary acidic protein （GFAP）, synaptophysin （Syn）, Chromogranin A （CgA）, cytokeratin （AEI/AE3）, epithelial membrane antigen （EMA） and Ki67 was performed on paraffin-embedded sections. Results： Among the six cases, five occurred in female patients, one was male, the age at diagnosis ranged from 2 to 15 years. Four cases were located in the hypothalamic area and optic pathway, one case in the third ventricle, and one case in left parietal lobe. On imaging, PMAs often appears as well-circumscribed mass. Microscopically, the tumor was composed of monomorphous bipolar （piloid） cells setting in a prominent myxoid background with an angiocentric radiating growth pattern in some areas. PMA lacked biphasic pattern, Rosenthal fibers and eosinophilic granular bodies which were usually typical in a classic pilocytic astrocytoma （PA）. Immunohistochemcal study showed that the tumor cells were diffusely positive for GFAP. Syn positive staining was observed in one case. The Ki67 labeling index measured less than 5%. Conclusion： PMA is a distinct aggressive variant of pilocytic astrocytoma with special histological and immunohistochemical features. It is typically a rare tumor of early childhood. Im- munohistochemical staining for GFAP and Syn is helpful in differential diagnosis.

Roles of NG2 glial cells in diseases of the central nervous system

NG2 cells are a novel distinct class of central nervous system（CNS） glial cells,characterized by the expression of the chondroitin sulfate proteoglycan NG2.They have been detected in a variety of human CNS diseases.As morphological,physiological and biomolecular studies of NG2 cells have been conducted,their roles have been gradually revealed.Research on cellular and molecular mechanisms in the pathophysiological state was built on the preliminary findings of their physiological functions;and in turn,this helps to clarify their physiological roles and leads to the identification of novel therapeutic targets.This review summarizes recent findings regarding the potential roles of NG2 cells in traumatic brain injury,multiple sclerosis,glioma,epilepsy,Alzheimer＇s disease and electroconvulsive therapy for depression.

Progress in the studies of low-molecular mass gelators with unusual properties

This article is intended to provide an overview of recent progress in the studies of cholesterol-based low-molecular mass gelators (LMMGs) with unusual properties,in particular,gelation and selective gelation at room temperature,gel emulsions and gel film formation,etc.Potential applications of the LMMGs in spilled oil collection and water purification are briefly presented.

Preparation of a cross-linked gelatin/bacteriorhodopsin film and its photochromic properties

Bacteriorhodopsin (BR) is a photochromic membrane protein isolated from a strain of halobacteria.Embedment of BR into a polymeric matrix enables the application of the photoactive protein as an optical material.In this work,a chemically crosslinked BR/gelatin film was prepared.The cross-linked film was found to be highly stable even under extreme alkaline or detergent circumstance while BR maintained its bioactivity.The treatments of base and detergents also led to dramatic prolongation of the lifetime of M photoproduct,which might be beneficial for potential applications such as information storage.The BR/gelatin film was demonstrated to tentatively record a simple pattern.

Inducible regulation of GDNF expression in human neural stem cells

Glial cell derived neurotrophic factor （GDNF） holds promises for treating neurodegenerative diseases such as Parkinson＇s dis- ease. Human neural stem cells （hNSCs） have proved to be a suitable cell delivery vehicle for the safe and efficient introduction of GDNF into the brain. In this study, we used hNSCs-infected with a lentivirus encoding GDNF and the hygromycin re- sistance gene as such vehicles. A modified tetracycline operator 7 （tetO7） was inserted into a region upstream of the EFI-α promoter to drive GDNF expression. After hygromycin selection, hNSCs were infected with a lentivirus encoding a KRAB-tetracycline repressor fusion protein （TTS）. TTS bound to tetO7 and suppressed the expression of GDNF in hNSCs. Upon administration of doxycycline （Dox） the TTS-tetO7 complex separated and the expression of GDNF resumed. The hNSCs infected with GDNF expressed the neural stem cell specific markers, nestin and sox2, and exhibited no significant change in proliferation rate. However, the rate of apoptosis in hNSCs expressing GDNF was lower compared with normal NSCs in response to actinomycin treatment. Furthermore, a higher percentage of Tuj-I positive cells were obtained from GDNF-producing NSCs under conditions that induced differentiation compared to control NSCs. The inducible expression of GDNF in hNSCs may provide a system for the controllable delivery of GDNF in patients with neurodegenerative diseases.

A novel preparation method of sulfonic functionalized silica： CH3SO3H as the sulfonic source and Al as the bridge

A novel approach is designed to optimize the synthesis of sulfonic-functionalized silica material. Results from 29Si and 27AI NMR suggest that the AI acts as the bridging atom connecting the methanesulfonate and silica matrix. Further pyridine-FTIR spectra followed by catalytic activity tests demonstrate that compared with previous methods, our new approach results in higher Lewis acid site concentration, higher thermal stability and superior catalytic activity. Moreover, the whole catalysis preparation procedure is environmentally friendly. Specifically, the silica matrix is synthesized through hydrolysis of tetrae- thylorthosilicate employing formic acid as hydro-catalyst, in which no surfactant species or precursors were involved.

Activity and Composition of Ammonia-Oxidizing Bacteria in an Aquic Brown Soil as Influenced by Land Use and Fertilization

The effects of long-term (19 years) different land use and fertilization on activity and composition of ammonia-oxidizing bacteria (AOB) in an aquic brown soil were investigated in a field experiment in Liaoning Province,China.The 19-year experiment conducted from 1990 to 2008 involved seven treatments designed: cropping rotation of soybean-corn-corn with no fertilizer (control,CK),recycled manure (RM),fertilizer nitrogen (N),phosphorous (P) and potassium (K) (NPK),NPK+RM,and no-crop bare land,mowed fallow,and non-mowed fallow.The results showed that the potential nitrification rates of the RM,NPK+RM,mowed fallow,and non-mowed fallow treatments were significantly higher (P < 0.05) than those of the CK and NPK treatments,indicating that the long-term applications of recycled manure and return of plant residues both significantly increased the activity of AOB.Although the application of NPK did not enhance soil potential nitrification because of decreased pH,available K had an important effect on potential nitrification.Denaturing gradient gel electrophoresis (DGGE) fingerprint profiles showed that no-crop treatments had an increase in the diversity of the AOB community compared to the CK,RM,and NPK treatments,implying that agricultural practices,especially tillage,had an adverse effect on the soil AOB community.The NPK+RM treatment had the most diverse DGGE patterns possibly because of the increased available P in this treatment.A phylogenetic analysis showed that most of the DGGE bands derived belonged to Nitrosospira cluster 3,not Nitrosospira cluster 2.These demonstrated that different land use and fertilization significantly influenced the activity and composition of the AOB community by altering the soil properties,mainly including pH,total C,available K,and available P.

Velvet antler polypeptide is able to induce differentiation of neural stem cells towards neurons in vitro

OBJECTIVE: To investigate the neural differentiation capacity of water extraction of velvet antler.METHODS: Velvet antler(Cervus Nippon Temminck) polypeptide(VAP) was used to differentiate neural stem cells(NSCs) towards neurons in the study. Firstly, we obtain the polypeptides of VAP by water extraction. Secondly, we observed the morphology, assayed the factors in the media by enzyme-linked immunosorbent assay, and detected the special neural molecules by immuno fl uorescence staining. NSCs were cultured on the cell climbing film. After neuronal differentiation, differentiated NSCs were mounted for immunocytochemistry with immunofluorescence technique.RESULTS: The differentiating cells look like neuron,some special factors, such as Glial cell line-derived neurotrophic factor, nerve growth factor, in the media can be detected while differentiated neuron-like cells can express the special neural molecules.CONCLUSION: Differentiation of NSCs towards neurons can be induced by velvet antler polypeptide.