体外化媒介批评的历时研究——技术的“道德恐慌”与“文化否思”

技术的不断迭代使传播媒介逐渐由体内向体外延伸,人类的传播媒介历经了以口语为代表的体内化媒介,向文字、印刷、电子及网络为代表的体外化媒介的转变。然而,每一种体外化媒介的产生与发展始终伴随着形形色色的批判与抗拒,从这些与媒介保持距离的行为中可以窥见人类对媒介的欲望与不服从的心理。本文从历时的角度梳理了从文字媒介时代到印刷媒介时代、电子媒介时代以及网络媒介时代这四个体外化媒介时代中不同的批判之声,每一种“道德恐慌”背后都指向历代体外化媒介的根本特性对人类认知、态度、行为上潜存的“文化否思”。人与技术的关系需要从体外化媒介的起点——文字媒介时代开始重思,予以每一种抗拒之声适切的理解,并对历代媒介技术可能带来的侵蚀做出整体性、全局性的否思。

我区首批试管牛犊在广西农学院陆续降生

广西首批试管牛犊于1990年4月6日至5月6日在广西农学院牧试站陆续降生,共4头,一公三母。这是本院卢克焕教授及其助手们采取国内外相结合的方式通力合作,刻苦攻关所取得的又一重大成果。广西农学院家畜繁殖研究室自1988年承担了国家及广西“黄牛胚胎工程”科研课题以来,全体研究人员在完全体外化培养胚胎的技术方面进行了深入细致的研究。

A Simulative Study on Effects of Climate Warming on Nutrient Contents and In Vitro Digestibility of Herbage Grown in Qinghai-Xizang Plateau

The increasing trend of air temperature along with the climate warming has been accepted gradually by scientists and by the general public. Qinghai_Xizang Plateau, a unique geographic unit due to high_altitude climate, is one of the most susceptible regions to climate warming. Its ecosystem is very fragile and sensitive to climate change. In order to get a better understanding of the impacts of climate warming on the nutrient contents of herbage grown in Qinghai_Xizang Plateau, a simulative study was implemented at Daban Moutain by using temperature differences resulted from sites selected at different altitudes and nutrient contents and in vitro digestibility were determined for assessing the quality of the grown herbage. There were significant downtrends in crude protein (CP), ether extract (EE) and nitrogen free extract (NFE) contents of herbage along with the increase of temperature. It had a positive correlation between temperature and content of acid detergent fibre (ADF), acid detergent lignin (ADL) in herbage. In vitro digestibility of herbage decreased along with the increase of temperature. The results of this study indicated that climate warming significantly influence nutrient contents and in vitro digestibility of herbage grown in Qinghai_Xizang Plateau. It is suggested that the future climate warming especially the gradual rise of the night temperature could cause negative effect on herbage quality grown in Qinghai_Xizang Plateau by decreasing CP, EE, and NFE contents and increasing some indigestible ingredients such as crude fibre (CF), neutral detergent fibre (NDF), ADF, and ADL. This, consequently, decreases the ruminant assimilation ability.

Protective Effects of Tea Polyphenol on Cerebral Ischemia-Reperfusion Injury in Rats and Its Scavenging Oxy-radical and Anticerebral Lipid Peroxidation Effects

AIM To study the protective effects of tea polyphenol (TP) on cerebral ischemia reperfusion injury in rats and its scavenging oxygen free radical(OFR) activities and antilipid peroxidation in vitro . METHODS Cerebral ischemia reperfusion injury was produced by bilateral ligation of the common carotid arteries with vagus nerves and reperfusion for 45 min. The mitochondrial lipid peroxidation of rat brain induced by oxygen free radical was measured by thiobarbituric acid spectrophotometry. Superoxide anion (O 2) from xanthine xanthine oxidase system and hydroxyl radical (·OH) from Fe 2+ -H 2O 2 system were determined with spectrophotometry. RESULTS During Cerebral ischemia reperfusion,TP improved the activities of superoxide dismutase ( P 【0 05), GSH peroxidase( P 【0 01) and catalase( P 【0 01), while decreasing the maiondialdchyde content in the brain( P 【0 05) and brain water content ( P 【0 01). Tea polyphenol possessed significantly scavenging effects on ·OH produced by Fenton reaction and O 2 produced by xanthine xanthine oxidase system (the IC 50 were 2 2 mmol·L -1 and 1 9 mmol·L -1 respectively). Tea polyphenol could significant inhibit the lipid peroxidation of cerbral mitochondrial membrane induced by ·OH in a concentration dependent manner. CONCLUSION The results indicate that tea polyphenol could protect the injury on cerebral ischemia reperfusion in rats for OFR, these effects may be related to its scavenging effects on oxygen free radicals and antilipid peroxidant.

从人工智能的发展审视技术统治论——以美剧《疑犯追踪》为例

我们一般的假设是电脑只会做人类所指定的事情,而作为"人工智能之父"的图灵极力推崇"机器会思考"这一富有争议的观点。那么,"机器能思考"对现实社会意味着什么呢?会思考的机器对作为发明者的人类来讲是天使,还是恶魔?笔者认为,首先需要明确的是人工智能是个体与外在世界之间的中介物,是个体认识和了解外在环境的工具,也是人体的体外化系统的最新进展。其次,人类智能创造并维持了人工智能,人工智能是人类无限潜能的结晶,但人工智能本质上不同于人类智能。关键的是。

对央行文化理论基础与层次关系的思考

在当前人民银行系统普遍关注央行文化建设的背景下,笔者试图从央行文化的理论基础和央行文化的层次关系两个角度入手,对央行文化建设做一些基础性、方向性的探索与思考。

4头试管牛犊在广西农学院降生

4头采用完全体外化培养技术生产的试管牛犊,于1990年4月6日至5月6日相继在广西农学院牧试站降生。这是继1988年元月我院卢克焕教授研究成功的世界第一例完全体外化试管小牛在爱尔兰共和国降生以来,由卢教授领导下的广西农学院家畜繁殖研究室全体研究人员取得的又一成果。该研究室自1988年3月起承担国家及广西“黄牛胚胎工程”科研课题以来。

An accelerated method to evaluate thymopentin release from microspheres in vitro

To design an accelerated method to evaluate thymopentin release from PLGA microspheres in vitro. Microspheres were prepared by double emulsion technique, using poly（lactide-co-glycolide） （PLGA） as carrier. At higher medium temperature （45℃, 50℃ and 55℃）, an accelerated release testing in short time was studied and correlated with the conventional release （37℃） in vitro. The release in vitro of thymopentin from PLGA microspheres at 45 ℃, 50℃ and 55℃ was significantly accelerated （P 〈 0.05）. In particular, at 50℃, an accelerated release （30 h） of the hydrophilic peptide from the PLGA matrix was achieved and correlated well with the conventional release （30 d）. An accelerated release testing in vitro at higher temperature could be used to monitor thymopentin release from PLGA microspheres.

A Bioactive Diterpene from the Chinese Herb Aster souliei

Aster souliei Franch, (Compositae) is a. herbaceous plant distributed innorth China. It has been used in folk medicine as antipyretic, detoxicant, expectorant andantitussive. In an effort to find biologically active components from Chinese medicinal plants ' ,we have examined the aerial parts of this herb, leading to the isolation of a clerodane-typediterpene, 18, 19-dihydroxy-5α, 10β-neo-cleroda-3, 13 (l4)-dien-16, 15-butenolide (1). In thispaper we report the structural elucidation, and the antitumor and antibacterial activities of thiscompound. It was found that 1 possesses moderate cytotoxicity against human leukemia cells (HL-60)and activity against microorganisms.

AFM Observation of GaN Grown on Different Substrates at Low Temperatures

Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods\ Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results\ It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion\ The analysis shows that no apparent relationship exists between the optical properties and layer morphology.

Effect of Cistanoside Compounds on Oxidative Stress and Immunity

Cistanoside compounds were studied as the scavengers of hydroxyl and superoxide anion free radicals with spin trapping ESR method in vitro. Low-temperature ESR technique, experimental technique of immunotoxicology and biochemical method were used to detect the level of reactive oxygen radicals in kidney tissue of rats and SOD level and GSH-Px activity in rat serum. The results indicated that cistanoside compounds could inhibit reactive oxygen free radicals in vitro and prevent and repair the free radical damages for diabetic nephropathy. The experimental data of 揷arbon-particle detection in mouse serum?showed that cistanoside compounds could improve the phagocytotis index of macrophages (Mj) in mice blood and increase the weights of immune organs of mice.

In vitro derivation of functional insulin-producing cells from human embryonic stem cells

The capacity for self-renewal and differentiation of human embryonic stem （ES） cells makes them a potential source for generation of pancreatic beta cells for treating type I diabetes mellitus. Here, we report a newly developed and effective method, carried out in a serum-free system, which induced human ES cells to differentiate into insulin-producing cells. Activin A was used in the initial stage to induce definitive endoderm differentiation from human ES cells, as detected by the expression of the definitive endoderm markers Sox17 and Brachyury. Further, all-trans retinoic acid （RA） was used to promote pancreatic differentiation, as indicated by the expression of the early pancreatic transcription factors pdxl and hlxb9. After maturation in DMEM/F12 serum-free medium with bFGF and nicotinamide, the differentiated cells expressed islet specific markers such as C-peptide, insulin, glucagon and glut2. The percentage of C-peptide-positive cells exceeded 15%. The secretion of insulin and C-peptide by these cells corresponded to the variations in glucose levels. When transplanted into renal capsules of Streptozotocin （STZ）-treated nude mice, these differentiated human ES cells survived and maintained the expression of beta cell marker genes, including C-peptide, pdxl, glucokinase, nkx6.1, lAPP, pax6 and Tcfl. Thirty percent of the transplanted nude mice exhibited apparent restoration of stable euglycemia; and the corrected phenotype was sustained for more than six weeks. Our new method provides a promising in vitro differentiation model for studying the mechanisms of human pancreas development and illustrates the potential of using human ES cells for the treatment of type I diabetes mellitus.

Chronological and Morphological Progression of Nucleus during Mouse Oocyte Maturation and Fertilization in vitro

The chronological and morphological changes of the nucleus during mouse oocyte maturation and fertilization were systematically studied. Although most oocytes went through GVBD 2-4 hrs after culture, 13.6% remained at GV stage 8 hrs after culture.TEM observation revealed that nucleoli of oocytes which failed to go through GVBD were composed of fibrillar-granular component,small vacuoles and fibrillar centers or showed small vacuoles on nuclear surface. During GVBD, the nucleoli became smaller and smaller and finally disappeared with the nuclear-associated chromatin dislocated to the periphery. Nuclear membrane with attached chromatin became folded and electronic dense cores appeared in the center of chromatin clumps at the same time.The last event of GVBD was the disruption of nuclear membrane.At the end of the 5th hr after culture, meiosis progressed to prometaphase I.Chromosomes,distributed in the original GV area free of organelles,were surrounded by large quantity of mitochondria and small SER vesicles. At the end of the 12th hr after culture,48. 1% of the oocytes emitted PB1.Decondensing sperm head and early male pronuclcus(mPN)with condensed nucleoli were found 1-2 hrs after insemination.The formation and enlargement of female PN(fPN) occurred a little earlier than that of mPN. 33.3% finished syngamy at 8-9 hrs after insemination.The process of nucleolus formation was reverse to that in GVBD. The oolemma modification caused by cortical reaction could effectively inhibit polyspermy.in contrast,there were sperm binding to the oolemma where CGs failed to be released. In addition, PB2 was emitted 2-5 hrs after insemination. The difference between PB1 and PB2 as well as the abstriction of polar body were also discussed.

Insulin-like growth factor binding protein-7 induces activation and transdifferentiation of hepatic stellate cells in vitro

AIM:To investigate the role of insulin-like growth factor binding protein-7 (IGFBP-7) in the activation and transdifferentiation of hepatic stellate cells (HSC) in vitro.METHODS:Rat HSC-T6 cells were cultured in separate dishes and treated with various concentration of transforming growth factor (TGF)-β1,IGFBP-7 or antiIGFBP-7 antibody for 24 h.The supernatant or a cytoplasm suspension was obtained from cultured HSC,followed by transfer of cells to form cell-coated dishes.Immunocytochemistry and Western blotting were used to analyze the expression of IGFBP-7 induced by TGF-β1 and the level of fibronectin,collagen and α-smooth muscle actin (SMA).The pro-apoptotic effect of antiIGFBP-7 antibody was determined by flow cytometry.RESULTS:Immunocytochemistry and Western blotting revealed that the expression of IGFBP-7 in TGF-β1 treated HSC was significantly up-regulated compared to that in the control group.In addition,fibronectin,collagen and α-SMA also showed enhanced expression in accordance with the transdifferentiation process in a dose-dependent manner to some extent.Moreover,flow cytometry suggested that anti-IGFBP-7 antibody induced apoptosis of activated HSC,which is responsible for the development of liver fibrosis,and may represent a novel pathway and target for therapeutic intervention.CONCLUSION:IGFBP-7 showed increased expression in activated HSC and played an important role in the activation and transdifferentiation process of HSC.AntiIGFBP-7 antibody may ameliorate liver fibrogenesis.

Highly efficient differentiation of human ES cells and iPS cells into mature pancreatic insulin-producing cells

Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.

Ex vivo differentiation of multipotent adult progenitor cells to skin epidermal cells

Objective： By establishing the indirect contact co-culture system, we studied the in vitro condition for MAPCs differentiating into epidermal cells and the transformation of MAPCs into epidermal cell phenotype. Methods： Cell culture insert membrane was used for substitute basal membrane and MAPCs, fibroblast cells （FCs） and mixture of MAPCs and epidermal cells and FCs were separately implanted into 2 sides of it. PKH26 was used to label cloned MAPCs; type IV collagen rapid adhering method was used to isolate and culture the skin epidermal cells from l-day-old SD rat. Results： Part of the MAPCs transformed into cells expressing keratin in the presence of peripheral epithelia and FCs. Type Ⅳ collagen rapid adhering method successfully selected rats＇ epidermal stem cells. The mixture of the 2 kinds of cells or indirect culture might promote the differentiation through mesenchymal factors secreted by dermis FC. Conclusion： We were the first to have established the in vitro model of MAPCs differentiation into epidermal cells, in which MAPCs were transformed into epithelium-like cells.

Purification and Activation In Vitro of MoFe Protein from a nifE Deleted Mutant Strain of Azotobacter vinelandii

The Deltanif E MoFe protein (Deltanif E Av1) was obtained by a chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from the unheated crude extract of nifE-deleted mutant strain (DJ35) of Azotobacter vinelandii Lipmann. The analysis by SDS-PAGE showed that the Delta nif EAv1 was similar to OP MoFe protein (Av1) of A. vinelandii in the kinds and molecular weights of subunits (alpha and beta subunit). When complemented with nitrogenase Fe protein (M), the A nif EAv1 had hardly any proton-reduction activity, but could be significantly activated by FeMoco extracted from OP Av1. After the Delta nif E Av1 was treated with an excess o-phenanthroline (o-phen) and chromatographied on Sephadex G-25 column under atmosphere of Ar, Delta nif E Av1(C) was obtained. In the presence of both Av2 and MgATP regeneration system, the Delta nif EAv1(C), rather than A nif EAv1, was significantly activated in vitro by a reconstituent solution containing Mn which composed of KMnO4, ferric homocitrate, Na2S, Na2S2O4 (DT) and dithiothreitol (DTT). But in the absence of MgATP or Av2, the activation of Delta nifE Av1(C) did not happen. It indicates that activation of Delta nif EAv1 by RS-Mn requires the pretreatment with o-phen and the simultaneous presence of Av2 and MgATP.

Optimization for Production of Intracellular Polysaccharide from Cordyceps ophioglossoides L2 in Submerged Culture and Its Antioxidant Activities in vitro

Cordyceps ophioglossoides is a valuable traditional medicinal material.We have found that intracellular polysaccharide(IPS) is the major biologically active ingredient in Cordyceps ophioglossoides.This study is the first time to optimize the yield of IPS from Cordyceps ophioglossoides.The optimal medium for IPS production consists of glucose 54.50 g·L·1,yeast powder 25.50 g·L·1,NaH2PO4 0.4 g·L·1 and K2HPO4 0.4 g·L·1.The suggested culture conditions are 24 ℃,initial pH 4.5 with a rotary speed of 120 r·min·1 for 168 h.The yield of IPS is 737.93 mg·L·1,which is 50% higher than the yield under the conditions prior to optimization.The anti-oxidative activities of IPS in Cordyceps ophioglossoides L2 are also characterized using various in vitro assay.The anti-oxidative activity may explain the reason why IPS from Cordyceps ophioglossoides can be used to fight against neurodegenerative dis-eases and menopausal symptoms.

Calcium phosphate nanoparticles show an effective activation of the innate immune response in vitro and in vivo after functionalization with flagellin

For subunit vaccines,adjuvants play a key role in shaping the magnitude,persistence and form of targeted antigen-specific immune response.Flagellin is a potent immune activator by bridging innate inflammatory responses and adaptive immunity and an adjuvant candidate for clinical application.Calcium phosphate nanoparticles are efficient carriers for different biomolecules like DNA,RNA,peptides and proteins.Flagellin-functionalized calcium phosphate nanoparticles were prepared and their immunostimulatory effect on the innate immune system,i.e.the cytokine production,was studied.They induced the production of the proinflammatory cytokines IL-8 （Caco-2 cells） and IL-1β（bone marrow-derived macrophages; BMDM） in vitro and IL-6 in vivo after intraperitoneal injection in mice.The immunostimulation was more pronounced than with free flagellin.