具有限时滞微生物连续培养模型的稳定性

讨论了由Monod动力学所描述的具有限时滞微生物连续培养模型的定性性态 ,给出了稳定性区域的划分 ,证明了当时滞变化时 ,平衡点的稳定性区域也随之改变 。

CdTe量子点双层加壳增强其化学和生物稳定性

为改善量子点在生物环境影像对氧化还原环境和金属离子的耐受性,使量子点适用于超长时间实时影像,使用改良的Stober方法对量子点分别进行了氨基硅烷化试剂和硅烷化试剂2次水解加壳,并利用热稳定为衡量指标优化了加壳条件.结果表明:双层加壳的量子点对铁、亚铁离子、高离子强度环境和氧化还原环境获得了很好的耐受性.双层加壳后量子点模拟用于超长时间实时荧光影像监测发现:与金黄色葡萄球菌共培养荧光可持续保留168 h,较未包壳量子点提高了14倍;与大肠杆菌共培养荧光可持续保留48h,较未包壳量子点提高了6倍.

人体生物钟

地球围绕太阳公转一周是一年,地球自转一周是昼夜24小时,人们称之为昼夜周期或自然时钟。生活在地球上的生物,受地球昼夜周期的影响,也形成了生物本身与之适应的昼夜周期变化,我们称之为生物时种。大脑内有只生物母时种大脑是人体的司令部,首先要顺应外界环境的影响。

东方神犬——仔藏獒的管理技术

为了对藏獒进行科学的饲养管理,不同的生物时期应进行适当的饲养管理。从出生至断奶的小藏獒称为仔藏獒,此阶段的正确饲养管理极为重要,是仔獒是否健壮和提高仔獒成活率的关键时期。 1.注意防寒避暑新生仔獒对体温的调节能力很差。因此,环境温度对仔獒的生命活动影响很大,

Development of Studies on RNA Interference

RNA interference （RNAi）, caused by endogenous or exogenous double- stranded RNA （dsRNA） homologous with target genes, refers to gene silencing widely existing in animals and plants. It was first found in plants, and now it has developed into a kind of biotechnology as well as an important approach in post- genome era. This paper is to summarize the achievements of studies on RNAi tech- nology in basic biology, medicine, pharmacy, botany and other fields.

Spatial and temporal variation of picoplankton distribution in the Yellow Sea, China

Seven surveys were carried out in April, September, October, December 2006 and March, May, August 2007 in the Yellow Sea, China. Variations in the spatial and temporal distribution of Synechococcus, picoeukaryotes and heterotrophic bacteria are quantified using flow cytometry. Synechococcus and heterotrophic bacteria are most abundant from late spring to autumn, while picoeukaryotes concentration is high in spring. Synechococcus and heterotrophic bacteria concentrated high in the northwest part of the Yellow Sea in spring and autumn, while picoeukaryotes distributed evenly over the whole study area except for a small frontal zone in the coastal area on the west （in spring） and central Yellow Sea （in autumn）. Under mixing conditions, the vertical distribution of the three picoplankton groups showed a well-mixed pattern. Upon a well-established stratification, the maximum abundance of picoplankton occurred above the mixed layer depth （-30 m）. Cell sizes of Synechococcus and picoeukaryotes were estimated by converting forward scatter signals （FSC） from cytometry analysis to cell diameter, showing the results of 0.65-0.82 um for Synechococcus and 0.85-1.08 um for picoeukaryotes. The average integrated carbon biomasses ranged 15.26-312.62 mgC/m2 for Synechococcus, 18.54-51.57 mgC/m2 for picoeukaryotes, and 402.63-818.46 mgC/m2 for heterotrophic bacteria. The distribution of Synechococcus and heterotrophic bacteria was temperature dependent, and picoplankton presence was poor in the Yellow Sea Cold Water Mass.

中医的医学模式与中医学心理学

医学模式属哲学范畴,指导医疗实践与医学发展,随医疗实践情况而确定。在西方,十五世纪进入“生物医学模式”,贡献众多。因社会发展,至十九世纪发现此一模式远远不适应实际需要,二十世纪70年代末变更为“社会-心理-生物医学模式”,趋于符合人的整体性的观念,面貌一新,医学心理学方面,尤为突出。西方医学模式为回顾性认识,其命名为事后确定。中医无医学模式一词,但《内经》中即明确提出“医道”,是指导医学发展方向和实践方法之意,其意义同于医学模式。医道除包含社会、心理、生物因素外,还有天地阴阳、四时经纪等“时”、“空”因素。这5个因素形成人的“天人合一,心身合一,人事相通”的整体性,故中医的医学模式为“时-空-社会-心理-生物医学模式”,为整体医学模式。它指导中医的发展与实践已两千余年,故为前瞻性的,其实用价值与现实意义,至今仍保持先进性。西方医学模式的转型,事实上是纳入中医学的模式中。西方医学模式随医学之进步而修正,现在已有“太空”,“潜水”等分科,疾病之发作与时间的关系,早有研究,现在又在研究生物钟,将来更改为“时-空-社会-心理-生物医学模式”,可以预期。中医学中也没有“医学心理学”这一名词,但是却有着极其丰富的相关内涵,历代医家在“心因”疾病的诊疗实践中,积累了丰富的临床经验,奠定了理论基础,形成“形与神俱”、“心身合一”的观念。在心理测验和心理治疗方面,自具特点、有的早于西方同类疗法千余年。

EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA I. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION

Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO - 3 N, NO - 2 N, NH + 4 N, SiO 2- 3 Si, PO 3- 4 P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq.(1) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C , the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D , the coefficient of water temperature’s effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant nutrient concentrations but low phytoplankton biomass in some waters is reasonably explained in this paper.

A Real-Time Photo-Realistic Rendering Algorithm of Ocean Color Based on Bio-Optical Model

Abstract A real-time photo-realistic rendering algorithm of ocean color is introduced in the paper, which considers the impact of ocean bio-optical model. The ocean bio-optical model mainly involves the phytoplankton, colored dissolved organic material （CDOM）, inorganic suspended particle, etc., which have different contributionsto absorption and scattering of light. We decompose the emergent light of the ocean surface into the reflected light from the sun and the sky, and the subsurface scattering light. We estab- lish an ocean surface transmission model based on ocean bidirectional reflectance distribution function （BRDF） and the Fresnel law, and this model＇s outputs would be the incident light parameters of subsurface scattering. Using ocean subsurface scattering algorithm combined with bio-optical model, we compute the scattering light emergent radiation in different directions. Then, we blend the re- flection of sunlight and sky light to implement the real-time ocean color rendering in graphics processing unit （GPU）. Finally, we use two kinds of radiance reflectance calculated by Hydrolight radiative transfer model and our algorithm to validate the physical reality of our method, and the results show that our algorithm can achieve real-time highly realistic ocean color scenes.

Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers

The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.

Spectral Characterization of Colored Dissolved Organic Matter for Productive Inland Waters and Its Source Analysis

This study examined the spatiotemporal dynamics of colored dissolved organic matter （CDOM） and spectral slope （S）, and further to analyze its sources in three productive water supplies （Eagle Creek, Geist and Morse reservoirs） from Indiana, USA. The re- sults showed that he absorption coefficient aCDOM（440） ranged from 0.37 m-1 to 3.93 m-1 with an average of 1.89 ± 0.76 m-1 （±SD） for the aggregated dataset, and S varied from 0.0048 nm -1 to 0.0239 nm-1 with an average of 0.0108 ±0.0040 nmI. A significant relation- ship between S and aCDOM（440） can be fitted with a power equation （S = 0.013 × aCDOM（440）-0.42, R2 = 0.612）, excluding data from Geist Reservoir during high flow （12 April 2010） and the Morse Reservoir on 25 June 2010 due to a T-storm achieves even higher determina- tion coefficient （R2 = 0.842）. Correlation analysis indicated that aCDOM（440） has strong association with inorganic suspended matter （ISM） concentration （0.231 〈 R2 〈 0.786） for each of the field surveys, and this trend followed the aggregated datasets （R2 = 0.447, p 〈 0.001）. In contrast, chlorophyll-a was only correlated with aCDOM（440） in summer and autumn （0.081 〈 R2 〈 0.763）, indicating that CDOM is mainly from terrigenous sources in early spring and that phytoplankton contributed during the algal blooming season. The S value was used to characterize CDOM origin. The results indicate that the CDOM source is mainly controlled by hydrological varia- tions, while phytoplankton originated organic matter also closely linked with CDOM dynamics in three productive reservoirs.

Pharmacokinetic study with N-Ile^1-Thr^2-63-desulfato-r-hirudin in rabbits by means of bioassay

Aim： To study the pharmacokinetic （PK） properties in rabbits treated with N-Ile^1-Thr^2-63-desulfato-r-hirudin （rH） newly developed in China by means of bioassay in order to provide preclinical experiment basis for its development as a novel anticoagulant agent. Methods： rH plasma concentration was determined using bioassay based on ex vivo antithrombin activity of rH. Normal rabbits received iv rH 4.0, 2.0 and 1.0 mg/kg or sc rH 2.0 mg/kg, respectively. The rabbits with acute severe renal failure were given iv rH 2.0 mg/kg. Results： The bioassay described in this paper met requirements for study of PK in rabbits. The major PK parameters after iv dosing were as follows： t1/2p 58.4-59 min. Vd 0.09-0.12 L/kg, CL 0.0035-0.0040 L/（kg·min）; AUC were proportional to the doses, ti/2 and CL did not change significantly with the doses. The sc bioavailability reached 94%. The rabbits suffering from acute severe renal failure presented 11-fold longer t1/2p and 13-fold greater.4 UC than normal healthy rabbits. Conclusion： rH exhibited rapid elimination, distribution was only limited to extracellular space and good absorption from sc site. The excretion ofrH by kidneys played a very important role in the elimination of rH. The PK ofrH could be described by the two- and one-compartment model after iv and sc dosing, respectively, and folio,wed linear kinetics.

High efficiency production of ginsenoside compound K by catalyzing ginsenoside Rb1 using snailase

The rare ginsenoside Compound K （C-K） is attracting more attention because of its good physiological activity and urgent need. There are many pathways to obtain ginsenoside C-K, including chemical and biological methods. Among these, the conversion of PPD-type ginsenosides by enzymatic hydrolysis is a trend due to its high efficiency and mild conditions. For effectively extracting from the other panaxadiol saponins, the conversion process for ginsenoside C-K was investigated using snailases in this study. The univariate experimental design and response surface methodology were used to determine the optimal hydrolysis conditions for the conversion of ginsenoside Rbl into ginsenoside C-K by snailases. The optimum conditions were as follows： pH 5,12, temperature 51 ℃, ratio of snailase/substrate 0.21, and reaction time 48 h. On the basis of these parameters, the addition of 1.0 mmol· L- 1 ferric ion was found to significantly improve the enzymolysis ofsnailases for the first time. With the above conditions, the maximum conversion rate reached 89.7%, suggesting that the process can obviously increase the yield of ginsenoside C-K. The bioassay tests indicated that the ginsenoside C-K showed anti-tumor activity in a series of tumor cell lines. Based on these results, we can conclude that the process of rare ginsenoside C- K production by enzymolysis with snailase is feasible, efficient, and suitable for the industrial production and application.

Effects of social isolation stress on immune response and survival time of mouse with liver cancer

AIM： To investigate the effects of isolation stress on mouse with liver cancer and possible associated mechanisms. METHODS： Transplantable murine hepatoma22 （H22） model was used to evaluate the effects of social isolation stress on murine liver cancer. Mice were immunized with sheep red blood cell （SRBC） and intraperitoneally inoculated with H22 cell, then divided into two groups, one reared individually as group （I） and the other reared in groups as group （G）. Titer of antibody to SRBC and interleukin 2 （IL-2） in serum was monitored. The survival time of mouse with liver cancer was observed. RESULTS： The titer of antibody to SRBC in group （G） was 1：24.5 and that in group （I） was 1：11.2. There was a significant difference between these two groups （t = 2.60, P = 0.02）. A significant difference in IL-2 concentration was observed between group （G） （39.6 ng/L） and group （I） （47.1 ng/L, t = 2.14, P = 0.046）. The survival time in group （G） （16.5 d） was markedly longer than that in group （I） （13.2 d, t = 3.46, P = 0.002）. CONCLUSION： Our study suggests that survival time of the mouse bearing H22 tumor is affected by the social isolation stress and the associated mechanism may be the immunological changes under the social isolation stress.

Multiphoton microscopy:An introduction to gastroenterologists

Multiphoton microscopy, relying on the simultaneous absorption of two or more photons by a fluorophore, has come to occupy a prominent place in modern biomedical research with its ability to allow real-time observation of a single cell and molecules in intact tissues. Multiphoton microscopy exhibits nonlinear optical contrast properties, which can make it possible to provide an exceptionally large depth penetration with less phototoxicity. This system becomes more and more an inspiring tool for a non-invasive imaging system to realize "optical biopsy" and to examine the functions of living cells. In this review, we briefly present the physical principles and properties of multiphoton microscopy as well as the current applications in biological fields. In addition, we address what we see as the future potential of multiphoton microscopy for gastroenterologic research.

Otolith development in larval and juvenile Schizothorax davidi： ontogeny and growth increment characteristics

Laboratory-reared Schizothorax davidi larvae and juveniles were examined to assess the formation and characteristics of David’s schizothoracin otoliths.Otolith development was observed and their formation period was verifi ed by monitoring larvae and juveniles of knownage.The results revealed that lapilli and sagittae developed before hatching,and the first otolith increment was identified at 2 days post hatching in both.The shape of lapilli was relatively stable during development compared with that of sagittae;however,growth of four sagittae and lapilli areas was consistent,but the posterior area grew faster than the anterior area and the ventral surface grew faster than the dorsal surface.Similarly,the sum length of the radius of the anterior and posterior areas on sagittae and lapilli were linearly and binomially related to total fish length,respectively.Moreover,daily deposition rates were validated by monitoring knownage larvae and juveniles.The increase in lapilli width was 1.88±0.080 0μm at the ninth increment,which reached a maximum and the decreased gradually toward the otolith edge,whereas that of sagittae increased more slowly.These results illustrate the developmental biology of S.davidi,which will aid in population conservation and fish stock management.

Effect of Sludge Retention Time on Nitrite Accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

Effects of processing pH stimulation on cooperative bioleaching of chalcopyrite concentrate by free and attached cells

In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.

A thermodynamic Approach to Rate Equations in Continuum Physics

The paper addresses the formulation of rate equations, via objective time derivatives, within continuum physics. The concept of objectivity is reviewed and distinction is made with material frame-indifference whose meaning is restricted to the invariance of the balance equations relative to Galilean frames. Objective time derivatives are defined to leave the tensor character of the appropriate field invariant within the set of Euclidean frames. Rate equations are required to involve objective time derivatives and to be consistent with the second law of thermodynamics. Here the general structure of objective time derivatives is established and the known derivatives of the physical literature are shown to be particular cases. Next, to fix ideas, a rate equation is considered for the model of heat conduction via a generalization of the Maxwell-Cattaneo equation with higher-order gradients as in the Guyer-Krumhansl equation. The thermodynamic restrictions are investigated and the expected effects, of the selected derivative of the heat flux, on the stress tensor are derived.

Discovery of Metastasis-Associated Biomarkers in Ovarian Cancer Using SELDI-TOF: An in Vitro and Clinical Study

OBJECTIVE To identify metastasis-related biomarkers in humanovarian cancer cell lines and in serum.METHODS We isolated total protein from cell lysis solutionsand cultured supernatants from 2 human ovarian cancer cell linesand used SELDI-TOF-MS to detect the differential expressionof the proteins in the 2 cell lines.The proteomic spectra weregenerated using weak cation exchange chips.The biomarkerswere validated by analyzing serum proteins or peptides in ovariancancer patients,relapsed ovarian cancer patients,patients withbenign ovarian tumors,and healthy people.RESULTS Four proteins in the culture supernatant fromHO-8910PM cells were up-regulated,relative to the culturesupernatant of HO-8910 cells.One protein (3,144 Da m/z value)was up-regulated in both the cell lysis solution and in the culturesupernatant of HO-8910PM cells.In addition,expression of the3,144 Da m/z protein differed significantly between serum fromthe 26 ovarian cancer patients,from the 22 relapsed ovarianpatients and from the 37 healthy women (P<0.01).However,therewas no difference between patients with benign ovarian tumorsand healthy people (P>0.5).CONCLUSION Ovarian cancer cell lines with high or lowmetastatic potential have distinct protein profiles.Protein 3,144Da m/z could be a useful biomarker for diagnosing ovarian cancermetastasis.