Simultaneous and rapid monitoring of biomass and biopolymer production by Sphingomonas paucimobilis using Fourier transform-near infrared spectroscopy

The application of Fourier Transform near infrared spectroscopy (FT-NIRS) to near real-time monitoring of polysaccharide and biomass concentration was investigated using a gellan-producing strain of Sphingomonas paucimobilis grown in a stirred tank reactor. Successful models for both biomass and gellan were constructed despite the physichochemical complexity of the viscous process fluid. Modelling of biomass proved more challenging than for gellan, partly because of the low range of biomass concentration but a model with a good correlation coefficient (0.94) was formulated based on second derivative spectra. The gellan model was highly satisfactory, with an excellent correlation coefficient (0.98), again based on second derivative spectra. No sample pre-treatment was required and all spectral scanning was carried out on whole broth. Additionally, both models should be robust in practice since both were formulated using low numbers of factors. Thus, the near real time simultaneous monitoring of gellan and biomass in this highly complex matrix using FT-NIRS potentially opens the way to greatly improved process control strategies.     

Statistical and Frequency-Amplitude Characteristics of Ultraweak Emissions of the Loach Eggs and Embryos under the Normal Conditions and upon Their Optic Interactions. 2. Changes in Characteristics of Ultraweak Emissions upon Optic Interaction of Groups of Embryos of Different Ages

We compared the characteristics of ultraweak emissions from groups of loach embryos of different ages in the presence or absence of optic interaction. The percentage of zero values of emission gradually increased during the first hour of optic interaction. The number and height of rare big pulses estimated by the value of kurtosis increased in parallel. In addition, the correlation between the Fourier spectra of optically interacting samples decreased at a higher rate than in the absence of optical contact. Just after the 1-hour optic interaction was terminated, the number of high pulses decreased in a younger interacting group and increased in the older one and the farther away the partner groups were in developmental stages, the more pronounced these differences were. Measurements of the Fourier spectra after long-term (12–22-hour) optic interactions have shown that an exchange of autocorrelation characteristics of the spectra took place among the samples: the sums of autocorrelation coefficients were inverted in the vast majority of cases, often with an overshoot or, at least, were smoothed over with reference to the control samples. We conclude that the previously described effects of optic interactions between groups of loach embryos of different ages could be due to changes in the frequency spectra of their ultraweak emissions.     

Trends in phenological phases in Europe between 1951 and 1996

Increases in air temperature due to the anthropogenic greenhouse effect can be detected easily in the phenological data of Europe within the last four decades because spring phenological events are particularly sensitive to temperature. Our new analysis of observational data from the International Phenological Gardens in Europe for the 1959–1996 period revealed that spring events, such as leaf unfolding, have advanced on average by 6.3 days (–0.21 day/year), whereas autumn events, such as leaf colouring, have been delayed on average by 4.5 days (+0.15 day/year). Thus, the average annual growing season has lengthened on average by 10.8 days since the early 1960s. For autumn events, differences between mean trends of species could not be detected, but for spring events there were differences between species, with the higher trends for leaf unfolding and flowering of shrubs indicating that changes in events occurring in the early spring are more distinct. These observed trends in plant phenological events in the International Phenological Gardens and results of other phenological studies in Europe, summarised in this study, are consistent with AVHRR satellite measurements of the normalized difference vegetation index from 1981 to 1991 and with an analysis of long-term measurements of the annual cycle of CO₂ concentration in Hawaii and Alaska, also indicating a global lengthening of the growing season. Received: 21 October 1999 / Accepted: 2 March 2000     

Generalized additive distributed lag models: quantifying mortality displacement

There are a number of applied settings where a response is measured repeatedly over time, and the impact of a stimulus at one time is distributed over several subsequent response measures. In the motivating application the stimulus is an air pollutant such as airborne particulate matter and the response is mortality. However, several other variables (e.g. daily temperature) impact the response in a possibly non-linear fashion. To quantify the effect of the stimulus in the presence of covariate data we combine two established regression techniques: generalized additive models and distributed lag models. Generalized additive models extend multiple linear regression by allowing for continuous covariates to be modeled as smooth, but otherwise unspecified, functions. Distributed lag models aim to relate the outcome variable to lagged values of a time-dependent predictor in a parsimonious fashion. The resultant, which we call generalized additive distributed lag models, are seen to effectively quantify the so-called 'mortality displacement effect' in environmental epidemiology, as illustrated through air pollution/mortality data from Milan, Italy.     

A biomechanical and spectroscopic study of bone from rats with selenium deficiency and toxicity

Selenium, being an essential mineral in the mammalian diet, is important in providing protection against oxidative damage. Numerous in vitro studies of selenium compounds reveal a very high correlation between catalytic activity of selenium compounds and toxicity. The present study was designed to investigate the effects of dietary selenium on the biomechanical properties of bone. New born rats of both sexes were fed with either a control, or a selenium- and vitamin E-deficient, or a selenium-excess and vitamin E-adequate diet. We obtained the stiffness (modulus of elasticity) of bones (femur and tibia) by tensile test for all groups considered. Both the deficient and the excess groups have decreased biomechanical strength with respect to the control group. To support our biomechanical results for both experimental groups, X-ray diffraction analysis and FTIR spectroscopic study were performed on the femurs and tibiae. The X-ray diffraction analysis showed that the intensities of the peak observed at around 2°=31.820, in the control femur and tibia are stronger than the intensities of the corresponding peak of two experimental groups. In FTIR spectroscopy, the disappearance and/or reduction of the intensities of some carbonate bands in the two experimental groups indicate that there is a decrease in crystallinity and mineral contents which, together with X-ray diffraction analysis, correlate very well with the biomechanical data.     

Structural time series models with feedback mechanisms

Structural time series models have applications in many different fields such as biology, economics, and meteorology. A structural times series model can be represented as a state-space model where the states of the system represent the unobserved components and the structural parameters have clear interpretations. This paper introduces a class of structural time series models that incorporate feedback from the latent components of the history. An iterative procedure is proposed for estimation. These models allow flexible and robust feedback mechanisms, have clear interpretations, and have a computationally efficient estimation procedure. They are applied to hormone data to characterize hormone secretion and to explore a potential feedback mechanism.     

红外光谱技术在生物过程监测中的应用

在线监测化学组分的浓度对许多生物过程都是十分必要的。然而,探头需耐高温灭菌的要求和生物体系自身的复杂性给许多分析技术的在线监测带来了困难。近几年,随仪器和数据处理技术的迅速发展,应用红外光谱技术对生物过程的原位或在线监测日益广泛。本文对红外过程分析技术进行了较全面的综述,介绍了红外分析的原理、进展及在生物过程监测中的应用。     

Crystal structure of R22L trichosanthin

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Darkling beetle communities in two geologically contrasting biotopes: testing biodiversity patterns by microsite comparisons

Studies at a microsite scale, where most of the environmental variation can be reduced to a few factors, may help to identify the actual contribution of a particular environmental factor to community organization. Climate is known to be an important factor for regulating animal diversity. However, for soil‐dwelling animals, the role of soil characteristics can hardly be extracted out because of the inter‐relationships between climate and soil. The community structure of soil‐dwelling darkling beetles inhabiting the two geologically highly contrasting west‐ and east‐facing slopes (WFS and EFS, respectively) of the Mediterranean island of Santorini (Greece) was investigated in a case study aiming to assess the separate influence of soil characteristics and climate. Eroded pumice soils of EFS allowed a higher abundance of darkling beetle individuals and biomass, hosting more productive vegetation and being more penetrable to fossorial larvae. Moreover, the two slopes differed significantly with respect to the abundance of certain species that are characterized by a peculiar morphological adaptation to different soil characteristics. Thus, local geological sharp divergence led to darkling beetle interslope community differences as a result of local selection towards certain species. However, the two communities are similar in terms of darkling beetle diversity, evenness, and species niche‐breadth. This demonstrates that sites sharing the same climatic conditions tend to have similarly structured darkling beetle communities, even if there are marked differences in soil characteristics that promote differences in species composition, thus suggesting that climate is the major factor for regulating species diversity. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 787–793.