Use of computerized dynamic posturography to assess balance in older adults after nighttime awakenings using zolpidem as a reference

<p>Abstract</p> <p>Background</p> <p>Computerized dynamic posturography (CDP) has been used to detect balance and stability impairments in adults of all ages. The goal of the current pilot study was to evaluate balance in healthy older adults after a middle-of-the-night awakening and to assess the ability of CDP to measure effects of bedtime zolpidem administration.</p> <p>Methods</p> <p>Two studies used CDP to evaluate balance in healthy older adults (≥ 65 years) during middle-of-the-night awakenings. The first study used a drug-free, single-period, within-subject, repeated measures study design. Subjects were evaluated during the day, pre-sleep, and 2 hours after bedtime for dynamic standing balance using the NeuroCom EquiTest Sensory Organization Test (SOT). Pairwise comparisons were made using one-way ANOVA. The second study was a single-blind, randomized, placebo-controlled, crossover study evaluating the ability of the SOT to measure medication-induced dynamic standing balance impairments using the commonly prescribed sleep medication, zolpidem 10 mg, as a test medication. Assessments were performed at night before zolpidem administration and then again 2 hours after bedtime. Comparisons were made between the 2 groups using an ANCOVA model.</p> <p>Results</p> <p>Twelve older adults (mean age 68.4 years) were evaluated in the first study. There was no significant difference between pre-sleep and middle-of-the-night assessments for the SOT composite score (<it>P </it>= 0.439). Eleven older adults (mean age 68.9 years) were evaluated in the second study. Zolpidem administration significantly decreased the SOT composite score after a middle-of-the-night awakening compared with placebo (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>In healthy older adults, getting up in the middle of the night did not have a significant effect on dynamic standing balance; however, bedtime administration of zolpidem 10 mg did lead to significant impairments. Thus, the SOT was able to measure medication-induced dynamic standing balance impairments and may be useful for future studies comparing balance effects of medications.</p

Enterprise Knowledge Creation Entropy Theoretical Analysis and Knowledge Entropy Model Study

Entering the 21st century, the knowledge economy as a new economic realizes the alternative of intellectual resources of material resources in the economic operational process, and it can greatly save energy and improve economic efficiency. Thus the value of existence of the enterprises in the context of knowledge economy is that the enterprises can conduct knowledge creation, transfer and use more efficient compared with the market. In essence, enterprises are the entity of knowledge production, the peculiarity of it owned to the difference between knowledge production ability and using ability. This paper used the similarity fundamental of the cross and comprehensive of natural science and social science, and imported the basic principles of entropy theory in thermodynamics to study the mechanism of knowledge creation, the key pathways and mechanisms, pointed out that the knowledge entropy can greatly save energy and improve economic efficiency. At the same time constructed a mathematical model of knowledge creation, and pointed out that any enterprises must continue to carry out knowledge creation and knowledge transfer to increase negative entropy to promote sustained and have a healthy development. Key words: Entropy theory; Knowledge creation; Mode

A new column-generation-based algorithm for VMAT treatment plan optimization

We study the treatment plan optimization problem for volumetric modulated arc therapy (VMAT). We propose a new column-generation-based algorithm that takes into account bounds on the gantry speed and dose rate, as well as an upper bound on the rate of change of the gantry speed, in addition to MLC constraints. The algorithm iteratively adds one aperture at each control point along the treatment arc. In each iteration, a restricted problem optimizing intensities at previously selected apertures is solved, and its solution is used to formulate a pricing problem, which selects an aperture at another control point that is compatible with previously selected apertures and leads to the largest rate of improvement in the objective function value of the restricted problem. Once a complete set of apertures is obtained, their intensities are optimized and the gantry speeds and dose rates are adjusted to minimize treatment time while satisfying all machine restrictions. Comparisons of treatment plans obtained by our algorithm to idealized IMRT plans of 177 beams on five clinical prostate cancer cases demonstrate high quality with respect to clinical dose–volume criteria. For all cases, our algorithm yields treatment plans that can be delivered in around 2 min. Implementation on a graphic processing unit enables us to finish the optimization of a VMAT plan in 25–55 s.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98593/1/0031-9155_57_14_4569.pd

Generation of Multicellular Tumor Spheroids with Microwell-Based Agarose Scaffolds for Drug Testing

Three dimensional multicellular aggregate, also referred to as cell spheroid or microtissue, is an indispensable tool for in vitro evaluating antitumor activity and drug efficacy. Compared with classical cellular monolayer, multicellular tumor spheroid (MCTS) offers a more rational platform to predict in vivo drug efficacy and toxicity. Nevertheless, traditional processing methods such as plastic dish culture with nonadhesive surfaces are regularly time-consuming, laborious and difficult to provide uniform-sized spheroids, thus causing poor reproducibility of experimental data and impeding high-throughput drug screening. In order to provide a robust and effective platform for in vitro drug evaluation, we present an agarose scaffold prepared with the template containing uniform-sized micro-wells in commercially available cell culture plates. The agarose scaffold allows for good adjustment of MCTS size and large-scale production of MCTS. Transparent agarose scaffold also allows for monitoring of spheroid formation under an optical microscopy. The formation of MCTS from MCF-7 cells was prepared using different-size-well templates and systematically investigated in terms of spheroid growth curve, circularity, and cell viability. The doxorubicin cytotoxicity against MCF-7 spheroid and MCF-7 monolayer cells was compared. The drug penetration behavior, cell cycle distribution, cell apoptosis, and gene expression were also evaluated in MCF-7 spheroid. The findings of this study indicate that, compared with cellular monolayer, MCTS provides a valuable platform for the assessment of therapeutic candidates in an in vivo-mimic microenvironment, and thus has great potential for use in drug discovery and tumor biology research

Statistical implications of pooling RNA samples for microarray experiments

BACKGROUND: Microarray technology has become a very important tool for studying gene expression profiles under various conditions. Biologists often pool RNA samples extracted from different subjects onto a single microarray chip to help defray the cost of microarray experiments as well as to correct for the technical difficulty in getting sufficient RNA from a single subject. However, the statistical, technical and financial implications of pooling have not been explicitly investigated. RESULTS: Modeling the resulting gene expression from sample pooling as a mixture of individual responses, we derived expressions for the experimental error and provided both upper and lower bounds for its value in terms of the variability among individuals and the number of RNA samples pooled. Using virtual pooling of data from real experiments and computer simulations, we investigated the statistical properties of RNA sample pooling. Our study reveals that pooling biological samples appropriately is statistically valid and efficient for microarray experiments. Furthermore, optimal pooling design(s) can be found to meet statistical requirements while minimizing total cost. CONCLUSIONS: Appropriate RNA pooling can provide equivalent power and improve efficiency and cost-effectiveness for microarray experiments with a modest increase in total number of subjects. Pooling schemes in terms of replicates of subjects and arrays can be compared before experiments are conducted

Storage Methods of Lactic Acid Bacteria Strains separated from DVS

Abstract: Randomly amplified polymorphic DNA (RAPD) and morphological observation and fermentation property analysis were used to evaluate the different storage methods of three lactic acid bacteria strains separated from Directed Vat Set (DVS). Methods: Evaluate the genome change of the different samples from different periods during 4℃ storage, -80℃ storage and lyophilization using RAPD. Observe the morphological features by microscopy after recovered from different time of storage, then used each strain as a starter culture of fresh milk, observe the fermentation properties. Results: The RAPD patterns and fermentation property of the three strains all changed during 4℃ and -80℃ storage, and they all showed a good stability when stored by lyophilization. Suggests: This is the first time to use RAPD technique and fermentation property observation in lactic acid bacteria storage research work, RAPD appears to be an efficient method for evaluating of storage effect of lactic acid bacteria strain

Disentangling the spatially combined and temporally lagged influences of climate oscillations on seasonal droughts in the East Asian monsoon influenced Poyang Lake Basin

Large-scale climate oscillations are the main forcings affecting regional meteorological droughts and being relevant to sources of their predictability. However, the physical mechanism of atmospheric teleconnections with respect to regional droughts is still not fully understood. In this study, a univariate-to-multivariate analysis framework is proposed to disentangle the spatially combined and temporally lagged effects of multiple oceanic-atmospheric oscillations on meteorological droughts at regional scale. Our study focuses on the largest freshwater lake basin of China, the Poyang Lake basin (PLB). Pearson\u27s correlation coefficient and cross-wavelet transform are used to analyze the pair-wise linear and non-linear correlations between droughts and each climate oscillation. Random forests model is used to reveal the combined influences of multiple climate oscillations. The associated atmospheric mechanism for the identified combination of climate indices with changing lags is explored by performing composite analysis. Regarding the spatially combined influences, the concurrence of El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) are the most important drought precursors. Regarding the temporally lagged influences, ENSO with lag of 11 months and NAO with lag of 2–3 months trigger meteorological droughts. The combined effect of preceding winter El Niño and late-summer negative NAO is the primary cause for triggering autumn droughts. The positive Eurasian teleconnection pattern, triggered by ENSO and NAO and favorable for anomalous northerly currents, is the main drought-prone circulation pattern for the PLB. These findings contribute to improved understanding of joint effects of lagged teleconnections for meteorological droughts, which could eventually lead to more skillful seasonal drought forecasting

Disentangling the spatially combined and temporally lagged influences of climate oscillations on seasonal droughts in the East Asian monsoon influenced Poyang Lake Basin

Large-scale climate oscillations are the main forcings affecting regional meteorological droughts and being relevant to sources of their predictability. However, the physical mechanism of atmospheric teleconnections with respect to regional droughts is still not fully understood. In this study, a univariate-to-multivariate analysis framework is proposed to disentangle the spatially combined and temporally lagged effects of multiple oceanic-atmospheric oscillations on meteorological droughts at regional scale. Our study focuses on the largest freshwater lake basin of China, the Poyang Lake basin (PLB). Pearson's correlation coefficient and cross-wavelet transform are used to analyze the pair-wise linear and non-linear correlations between droughts and each climate oscillation. Random forests model is used to reveal the combined influences of multiple climate oscillations. The associated atmospheric mechanism for the identified combination of climate indices with changing lags is explored by performing composite analysis. Regarding the spatially combined influences, the concurrence of El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) are the most important drought precursors. Regarding the temporally lagged influences, ENSO with lag of 11 months and NAO with lag of 2–3 months trigger meteorological droughts. The combined effect of preceding winter El Niño and late-summer negative NAO is the primary cause for triggering autumn droughts. The positive Eurasian teleconnection pattern, triggered by ENSO and NAO and favorable for anomalous northerly currents, is the main drought-prone circulation pattern for the PLB. These findings contribute to improved understanding of joint effects of lagged teleconnections for meteorological droughts, which could eventually lead to more skillful seasonal drought forecasting

Brain Activation of Elite Race Walkers in Action Observation, Motor Imagery, and Motor Execution Tasks: A Pilot Study

Walking plays an important role in human daily life. Many previous studies suggested that long-term walking training can modulate brain functions. However, due to the use of measuring techniques such as fMRI and PET, which are highly motion-sensitive, it is difficult to record individual brain activities during the movement. This pilot study used functional near-infrared spectroscopy (fNIRS) to measure the hemodynamic responses in the frontal-parietal cortex of four elite race walkers (experimental group, EG) and twenty college students (control group, CG) during tasks involving action observation, motor imagery, and motor execution. The results showed that activation levels of the pars triangularis of the inferior frontal gyrus (IFG), dorsolateral prefrontal cortex (DLPFC), premotor and supplementary motor cortex (PMC and SMC), and primary somatosensory cortex (S1) in the EG were significantly lower than in the CG during motor execution and observation tasks. And primary motor cortex (M1) of EG in motor execution task was significantly lower than its in CG. During the motor imagery task, activation intensities of the DLPFC, PMC and SMC, and M1 in the EG were significantly higher than in the CG. These findings suggested that the results of motor execution and observation tasks might support the brain efficiency hypothesis, and the related brain regions strengthened the efficiency of neural function, but the results in motor imagery tasks could be attributed to the internal forward model of elite race walkers, which showed a trend opposed to the brain efficiency hypothesis. Additionally, the activation intensities of the pars triangularis and PMC and SMC decreased with the passage of time in the motor execution and imagery tasks, whereas during the action observation task, no significant differences in these regions were found. This reflected differences of the internal processing among the tasks