A joint model of the contractile system of striated muscle (preliminary calculations)

Values of the variables of a model of the muscle contractile apparatus were calculated on the basis of a previously described theoretical system JMCSM (i.e. the Joint Model of the Contractile System of Muscle) and after introducing some necessary simplifying presuppositions. The calculations made it possible to compare the model with the original biological system and provided data needed for the subsequent stage of simulation experiments. The properties of the model are apparently not inconsistent with the properties of the original biological system. The basic equation of the theoretical model could be expressed in the form analogous to Hill's equation; the procedure by which the equations were derived and the interpretation of their parameters are mutually independent. The model also suggests a different interpretation of the dependence of the heat of shortening on other quantities of the system. It is necessary to consider these calculations and their results as preliminary with regard to the simplifying presuppositions and to the possible inaccuracies of the estimations of input data.     

ENM Components: a new set of web service‐based workflow components for ecological niche modelling

Ecological niche modelling (ENM) Components are a set of reusable workflow components specialized for performing ENM tasks within the Taverna workflow management system. Each component encapsulates specific functionality and can be combined with other components to facilitate the creation of larger and more complex workflows. One key distinguishing feature of ENM Components is that most tasks are performed remotely by calling web services, simplifying software setup and maintenance on the client side and allowing more powerful computing resources to be exploited. This paper presents the current set of ENM Components in the context of the Taverna family of tools for creating, publishing and sharing workflows. An example is included showing how the components can be used in a preliminary investigation of the effects of mixing different spatial resolutions in ENM experiments.     

Colorimetric determination of phytate in unpurified extracts of seeds and the products of their processing

The addition of orthophosphate (up to 20 micrograms/ml of phosphorus) and chlorogenic acid (up to 50 micrograms/ml) does not impair the colorimetric assay of phytate based on the decoloration of Fe3+-sulfosalicylate complex (M. Latta, and M. Eskin (1980) J. Agric. Food Chem. 28, 1313-1315). Phytate was determined in 14 samples of seed meal and protein isolates containing inorganic phosphate and chlorogenic acid. There was no difference between the results of the analysis using crude extracts and those using purified extracts. It is therefore possible to avoid the preliminary purification of extracts as in the original method, thereby simplifying and accelerating the phytate assay to a considerable extent.     

Histological study of Goniodoris castanea Alder and Hancock, 1845 (Nudibranchia, Doridoidea, Goniodorididae)

The major organ systems of Goniodoris castanea were investigated by histological means, with an emphasis on those structures that are difficult to see by dissection. The species is characterized by some peculiar features that are unique or seldom within the Nudibranchia, such as the complete absence of specialized vacuolated cells, the presence of globular salivary glands, the presence of cuticular structures in the proximal intestine, a muscular sphincter around the distal vaginal duct, and the position of the blood gland closer to the pericardium than to the nervous system. Some of these characters are discussed in a phylogenetic context, although a thorough phylogenetic analysis is preliminary, due to lack of knowledge of probably related species.     

A quantitative dynamic concept of the interphase partition of lipids: application to bile salt-lecithin-cholesterol mixed micelles

A system is proposed for a quantitative classification of lipids, based on interphase partition coefficients. This system enables calculation of exchanges of lipid molecules between phases. The mass/volume chemical unit mol X cm-3, strictly derived from the CGS system, is used, thus simplifying mathematical relations. Applied to bile salt-lecithin-cholesterol mixed micelles, this dynamic concept gives new insight into the variations of physico-chemical parameters. Experimental results obtained with the glycodesoxycholate and the taurocholate show a striking difference in partition coefficients between aqueous and mixed bile salt-lecithin interfacial phases. A new model applying triangular co-ordinates to a bile salt-lecithin-cholesterol mixed lipid phase is described.     

Vibrotactile feedback for conveying object shape information as perceived by artificial sensing of robotic arm

This work is a preliminary study towards developing an alternative communication channel for conveying shape information to aid in recognition of items when tactile perception is hindered. Tactile data, acquired during object exploration by sensor fitted robot arm, are processed to recognize four basic geometric shapes. Patterns representing each shape, classified from tactile data, are generated using micro-controller-driven vibration motors which vibrotactually stimulate users to convey the particular shape information. These motors are attached on the subject’s arm and their psychological (verbal) responses are recorded to assess the competence of the system to convey shape information to the user in form of vibrotactile stimulations. Object shapes are classified from tactile data with an average accuracy of 95.21 %. Three successive sessions of shape recognition from vibrotactile pattern depicted learning of the stimulus from subjects’ psychological response which increased from 75 to 95 %. This observation substantiates the learning of vibrotactile stimulation in user over the sessions which in turn increase the system efficacy. The tactile sensing module and vibrotactile pattern generating module are integrated to complete the system whose operation is analysed in real-time. Thus, the work demonstrates a successful implementation of the complete schema of artificial tactile sensing system for object-shape recognition through vibrotactile stimulations.     

Head-to-head comparison of serum fractionation techniques

Multiple approaches for simplifying the serum proteome have been described. These techniques are generally developed across different laboratories, samples, mass spectrometry platforms, and analysis tools. Hence, comparing the available schemes is impossible from the existing literature because of confounding variables. We describe a head-to-head comparison of several serum fractionation schemes, including N-linked glycopeptide enrichment, cysteinyl-peptide enrichment, magnetic bead separation (C3, C8, and WCX), size fractionation, protein A/G depletion, and immunoaffinity column depletion of abundant serum proteins. Each technique was compared to results obtained from unfractionated human serum. The results show immunoaffinity subtraction is the most effective means for simplifying the serum proteome while maintaining reasonable sample throughput. The reported dataset is publicly available and provides a standard against which emergent technologies can be compared and evaluated for their contribution to serum-based biomarker discovery.     

The subcellular calcium distribution in the smooth muscle cells of the pig coronary artery

In order to complete preliminary investigations on the subcellular calcium localisation in smooth muscle cells, further experiments are presented using smooth muscle cells from the coronary artery of the pig. The methods used were a precipitation technique using potassium oxalate and autoradiography using ⁴⁵Ca. In all cases we were able to reproduce the results obtained in our preliminary study. The preparations clearly show calcium oxalate precipitates in the cell membrane, the sarcoplasmic reticulum, the microvesicles, mitochondria and the nucleus membrane. These findings were supported by silver grain distributions in autoradiograms obtained by means of ⁴⁵Ca. The qualitative results obtained histochemically are in good agreement with estimations of the calcium distribution in subcellular fractions obtained by atomic absorption spectrophotometry.     

纳米粒子表面修饰对其与细胞膜相互作用的影响

纳米粒子在生物医学上的应用越来越广泛,其进入细胞的机制与规律是设计与开发的基础．已有研究发现,表面修饰不同亲疏水性基团的金纳米粒子,在内吞机制被抑制时,进入细胞的能力明显不同．更特别的是,粒子表面亲水性基团与疏水性基团呈间隔条纹规则排列的纳米粒子,与其他修饰成分相同仅排列不同的纳米粒子进入细胞的规律区别显著．这一特殊现象无法用已有的纳米粒子进入细胞的机制解释．本文针对该研究结果,将纳米粒子与细胞的体系简化,定量分析了3种不同纳米粒子进入细胞前后的不同状态,计算获得了表面修饰不同亲疏水性基团的纳米粒子与细胞膜之间相互作用的Flory．Huggins自由能．结果发现,修饰规则间隔排列亲疏水基团的纳米粒子,其作用自由能在与细胞接触前后变化最大．研究结果不仅解释了实验发现,同时预示了纳米粒子进入细胞的新机制．     

Cre/<Emphasis Type="Italic">lox</Emphasis>-mediated marker gene excision in transgenic maize (Zea mays L.) plants

After the initial transformation and tissue culture process is complete, selectable marker genes, which are used in virtually all transformation approaches, are not required for the expression of the gene of interest in the transgenic plants. There are several advantages to removing the selectable marker gene after it is no longer needed, such as enabling the reuse of selectable markers and simplifying transgene arrays. We have tested the Cre/lox system from bacteriophage P1 for its ability to precisely excise stably integrated marker genes from chromosomes in transgenic maize plants. Two strategies, crossing and autoexcision, have been tested and demonstrated. In the crossing strategy, plants expressing the Cre recombinase are crossed with plants bearing a transgene construct in which the selectable marker gene is flanked by directly repeated lox sites. Unlike previous reports in which incomplete somatic and germline excision were common, in our experiments complete somatic and germline marker gene excision occurred in the F₁ plants from most crosses with multiple independent Cre and lox lines. In the autoexcision strategy, the cre gene, under the control of a heat shock-inducible promoter, is excised along with the nptII marker gene. Our results show that a transient heat shock treatment of primary transgenic callus is sufficient for inducing cre and excising the cre and nptII genes. Genetic segregation and molecular analysis confirmed that marker gene removal is precise, complete and stable. The autoexcision strategy provides a way of removing the selectable marker gene from callus or other tissues such as embryos and kernels.Communicated by D. Hoisington     

Subcellular Localization of Gram-Negative Bacterial Proteins Using Sparse Learning

One of the main challenges faced by biological applications is to predict protein subcellular localization in an automatic fashion accurately. To achieve this in these applications, a wide variety of machine learning methods have been proposed in recent years. Most of them focus on finding the optimal classification scheme and less of them take the simplifying the complexity of biological system into account. Traditionally such bio-data are analyzed by first performing a feature selection before classification. Motivated by CS (Compressive Sensing), we propose a method which performs locality preserving projection with a sparseness criterion such that the feature selection and dimension reduction are merged into one analysis. The proposed sparse method decreases the complexity of biological system, while increases protein subcellular localization accuracy. Experimental results are quite encouraging, indicating that the aforementioned sparse method is quite promising in dealing with complicated biological problems, such as predicting the subcellular localization of Gram-negative bacterial proteins.     

Dynamics of a chemostat in which one microbial population feeds on another

Under certain simplifying hypotheses, a chemostat in which one microbial population feeds on another can be described by a system of three ordinary differential equations. A study is conducted to find which features of the equations are the most important to the dynamics of the system; it is found that the main influence comes from the from the particular form of the specific growth rate of the feeding population. Some conditions are derived that relate the form of the specific growth rate of the feeding population to the dynamic behaviour of the system.     

Preliminary Selection of Sires on Partial Records in Dairy Cattle

Progeny testing of sires is costly as well as time consuming. The cost and testing time for part sample of sires can be reduced by basing sire evaluation on partial first lactation records. But it results in genetic loss due to decrease in the accuracy of selection. The present paper is an empirical attempt to study the optimum level of preliminary culling on partial records from two different considerations for both large and small populations. It is seen that even for moderate genetic correlation between partial and complete records ( = 0.6) preliminary culling as high as 50% can be effected with advantage.     

Escherichia coli gpt gene provides dominant selection for vaccinia virus open reading frame expression vectors.

Mycophenolic acid, an inhibitor of purine metabolism, was shown to block the replication of vaccinia virus in normal cell lines. This observation led to the development of a dominant one-step plaque selection system, based on expression of the Escherichia coli gpt gene, for the isolation of recombinant vaccinia viruses. Synthesis of xanthine-guanine phosphoribosyltransferase enabled only the recombinant viruses to form large plaques in a selective medium containing mycophenolic acid, xanthine, and hypoxanthine. To utilize the selection system efficiently, we constructed a series of plasmids that contain the E. coli gpt gene and allow insertion of foreign genes into multiple unique restriction endonuclease sites in all three reading frames between the translation initiation codon of a strong late promoter and synthetic translation termination sequences. The selection-expression cassette is flanked by vaccinia virus DNA that directs homologous recombination into the virus genome. The new vectors allow high-level expression of complete or partial open reading frames and rapid construction of recombinant viruses by facilitating the cloning steps and by simplifying their isolation. The system was tested by cloning the E. coli beta-galactosidase gene; in 24 h, this enzyme accounted for approximately 3.5% of the total infected-cell protein.     

Evaluation of a Novel Laser-assisted Coronary Anastomotic Connector - the Trinity Clip - in a Porcine Off-pump Bypass Model

To simplify and facilitate beating heart (i.e., off-pump), minimally invasive coronary artery bypass surgery, a new coronary anastomotic connector, the Trinity Clip, is developed based on the excimer laser-assisted nonocclusive anastomosis technique. The Trinity Clip connector enables simplified, sutureless, and nonocclusive connection of the graft to the coronary artery, and an excimer laser catheter laser-punches the opening of the anastomosis. Consequently, owing to the complete nonocclusive anastomosis construction, coronary conditioning (i.e., occluding or shunting) is not necessary, in contrast to the conventional anastomotic technique, hence simplifying the off-pump bypass procedure. Prior to clinical application in coronary artery bypass grafting, the safety and quality of this novel connector will be evaluated in a long-term experimental porcine off-pump coronary artery bypass (OPCAB) study. In this paper, we describe how to evaluate the coronary anastomosis in the porcine OPCAB model using various techniques to assess its quality. Representative results are summarized and visually demonstrated.     

The Effects of Scheduling Rules and Routing Flexibility on the Performance of a Random Flexible Manufacturing System

The increased use of flexible manufacturing systems to efficiently provide customers with diversified products has created a significant set of operational challenges for managers. Many issues concerning procedures and policies for the day-to-day operation of these systems still are unresolved. Previous studies in this area have concentrated on various problems by isolating or simplifying the systems under study. The primary objective of this study is to extend previous research by examining the effects of scheduling rules and routing flexibility on the performance of a constrained, random flexible manufacturing system (FMS). Other experimental factors considered are shop load, shop configuration, and system breakdowns. Within the bounds of this experiment, the results indicate that, in the presence of total routing flexibility, the effects of shop load, system breakdowns, and scheduling rules are significantly dampened. In particular, when total routing flexibility exists, the choice of scheduling rules is not critical. We also show that the behavior of scheduling rules in a more constrained FMS environment (i.e., where system breakdowns occur and material handling capability is limited) is consistent with the findings of previous research conducted under less constrained environments. Finally, results indicate that the shop configuration factor has little or no impact on a system's flow-time performance.     

Stereotactic heavy-particle irradiation of intracranial arteriovenous malformations

Stereotactic irradiation appears to be effective in causing partial or complete thrombosis of AVM that are not surgically resectable. Use of heavy particles generated in a cyclotron allows better spatial definition and dose distribution than do other methods, allowing larger AVM to be treated. From these preliminary results, it is evident that heavy-particle irradiation therapy, like proton beam therapy, does not offer protection from recurrent hemorrhage for at least 12 months, nor is it devoid of major complications; it does offer a noninvasive mode of therapy for AVM that are difficult to treat surgically, however.