A new method to measure foot contact

A new method to measure foot contact is described. It consists of a pressure sensitive transducer attached to one end of a flexible silicone rubber tube. A reliable indicator of foot contact is obtained with the tube glued to the outer perimeter of the sole of a shoe.     

A novel method for detergent concentration determination

A fast and precise method for detergent concentration determination is presented. (Patent applications for the method described here have been submitted (EP05011904 and US60/702,261). Depending on the interest of the scientific community, the system will be commercialized. (For further information contact Hervé-W. Rémigy at the e-mail address below.) A small droplet of the detergent solution is deposited on a piece of Parafilm M and side views are recorded by two orthogonally arranged TV cameras. The droplet contours are then approximated by ellipses to determine the contact angles. Comparison of the observed contact angle values to calibrated standard curves of known detergent concentrations gives the concentration of the detergent assessed. A range of commonly used detergents was studied to demonstrate the reproducibility and precision of this simple method. As a first application, the detergent binding capacity of the Escherichia coli galactose/proton symporter (GalP) was assessed. Aggregation of GalP was observed when <260 +/- 5 dodecyl-beta,D-maltoside molecules were bound to one GalP molecule. These measurements document the efficacy of the drop-shape based detergent concentration determination described.     

A method for externally attaching radio transmitters to minimize dermal irritation

A method for externally attaching transmitters to fishes is described that reduces contact between the transmitter and the fish, thus reducing the potential for dermal irritation.     

A method for in situ embedding of cultured cells grown on plastic surfaces

Summary A method is described for the electron microscopic visualization of contact relationships between monolayer cells and the supporting surface of the plastic culture vessel.     

A neural network based predictor of residue contacts in proteins

We describe a method based on neural networks for predicting contact maps of proteins using as input chemicophysical and evolutionary information. Neural networks are trained on a data set comprising the contact maps of 200 non-homologous proteins of well resolved three-dimensional structures. The systems learn the association rules between the covalent structure of each protein and its correspondent contact map by means of a standard back propagation algorithm. Validation of the predictor on the training set and on 408 proteins of known structure which are not homologous to those contained in the training set indicate that this method scores higher than statistical approaches previously described and based on correlated mutations and sequence information.     

A Rapid Method for Screening Large Numbers of Environmental Microorganisms for Antiviral Activity

A new method for screening microbial colonies endowed with antiviral activity is described. It is based on close contact between microbial agar cultures and agar-covered virus-infected-cell monolayers and allows the screening of large numbers of colonies in just a few months.     

Development of a transient large strain contact method for biological heart valve simulations

A new 2D method to implement transient contact using Comsol Multiphysics (finite element analysis software that enables multiphysics simulations) is described, which is based on Hertzian contact. This method is compared to the existing (default) contact method that does not enable real transient simulations, but instead performs steady-state solutions where time is a constant. The two types of contact modelling have been applied to simple 2D biological heart valve models, undergoing strains in the region of 10% under 20 kPa pressure (applied over 0.3 s). Both the methods predicted comparable stress patterns, locations of peak stresses, deformations and directions of principal stress. The default contact method predicted slightly greater contact stresses, but spreads over a shorter surface length than the new contact method. The default contact method is useful for contact systems with little transient dependency, due to ease of use. However, where transient conditions are important the new contact method is preferred.     

A Study on Protein Residue Contacts Prediction by Recurrent Neural Network

1IntroductionThe three-dimensional(3D)structure of a proteinis perhaps the most important of all its features,since itdetermines completely how the protein functions andinteracts with other molecules.Most biological mech-anisms at the protein level are based on shape-complementarity,so that proteins present particularconcavities and convexities that allow them to bind toeach other and formcomplexstructures,and tendon.Forthis reason,for instance,the drug design problem con-sists primarily in th…     

定量测定储粮害虫胃毒作用的方法——混药薄片法

本实验制定一种定量测定储粮害虫胃毒作用的方法,命名为混药薄片法。通过试验验证饲料薄片对烟草甲Lasioderma serricorne(Fabricius)的幼虫成活率、发育历期、虫体重量、产卵量等生长发育无影响。在排除烯虫酯对烟草甲的触杀作用的前提下,将混有烯虫酯溶液的混药薄片作为饲料饲养烟草甲3龄幼虫,得到烯虫酯对烟草甲3龄幼虫的准确致死剂量为(0.46±0.03)μg。     

A simple method for collecting and mounting ribboned serial sections of epoxy embedded specimens

A simple and rapid method of handling ribboned serial sections of epoxy embedded specimens is described. Ribbons are cut from a block having the leading and trailing sides coated with contact cement. A scoop made from polyethylene tubing is used to remove a ribbon of sections from the boat of a glass or diamond knife and to transfer it to a pool of water on a microscope slide. Many ribbons (comprising hundreds of sections) can be mounted on a single slide. This method requires the construction of only one simple, inexpensive tool, the polyethylene scoop, and otherwise utilizes only items commonly available in the laboratory.     

A Simple Method for Collecting and Mounting Ribboned Serial Sections of Epoxy Embedded Specimens

A simple and rapid method of handling ribboned serial sections of epoxy embedded specimens is described. Ribbons are cut from a block having the leading and trailing sides coated with contact cement. A scoop made from polyethylene tubing is used to remove a ribbon of sections from the boat of a glass or diamond knife and to transfer it to a pool of water on a microscope slide. Many ribbons (comprising hundreds of sections) can be mounted on a single slide. This method requires the construction of only one simple, inexpensive tool, the polyethylene scoop, and otherwise utilizes only items commonly available in the laboratory.     

A two-centre evaluation of the human organotypic skin explant culture model for screening contact allergens

Animal models are considered to be the "gold standard" for determining the potential contact allergenicity of low molecular weight chemicals. However, governmental regulations and ethical considerations limit the use of animals for such purposes. There is therefore a need for in vitro alternative models. The human organotypic skin explant culture (HOSEC) model is reported to be a promising alternative method for the predictive testing of contact allergens. The accelerated migration of Langerhans cells from the epidermis upon exposure to contact allergens is used to identify chemicals that are potentially capable of inducing a delayed-type hypersensitivity. In the study described in this paper, the model was further refined, and used, in two independent laboratories, to screen 23 low molecular weight compounds of known classification for their allergenicity. Each laboratory was able to accurately detect the contact allergens, despite small variations in the protocols used. However, the classification of dermal irritants, which have often been falsely classified as allergens, varied between the two laboratories. Despite the current limitations of the HOSEC model, the accuracy of the predictions made (sensitiser or non-sensitiser) compare favourably with classifications obtained with commonly used animal models. The HOSEC model has the potential to be developed further as an in vitro alternative to animal models for screening for contact allergens.     

Experimental measurement and quantification of frictional contact between biological surfaces experiencing large deformation and slip

Interactions between contacting biological surfaces may play significant roles in physiological and pathological processes. Theoretical models have described some special cases of contact, using one or more simplifying assumptions. Experimental quantification of contact could help to validate theoretical analyses. The objective of this study was to develop a general mathematical approach describing the dynamics of deformation and relative surface motion between contacting bodies and to implement this approach to describe the contact between two experimentally tracked tissue surfaces. A theoretical formulation (in 2-D and 3-D) of contact using the movement of discrete tissue markers is described. The method was validated using theoretically generated 3-D datasets, with <1% error for a wide range of parameters. The method was applied to the contact loading of opposing articular cartilage tissues, where displacements of cell nuclei were tracked optically and used to quantify the movements and deformations of the surfaces. Compared to tissues with matched material properties, tissues with mismatched material properties exhibited increased disparities in lateral expansion and relative motion (sliding) between the contacting surfaces.     

A simple method for assaying contact toxicities of insecticides,with results of tests of some organic compounds against Calandra granaria L

A simple method of testing the contact action of insecticides either as residual dry deposits or as oil films is described. Tests with crystalline deposits of D.D.T. indicated that this method of assay was not sufficiently sensitive for practical use, but tests with oil films could be used. Some of the factors governing the toxicity of D.D.T. in the two systems are discussed, and the results of tests with several organic compounds are given.     

A new method of sample application for horizontal slab polyacrylamide gel electrophoresis

A new method of sample application for horizontal slab polyacrylamide gel electrophoresis has been developed which solves the main problems associated with existing systems. A quick, simple procedure is described for placing a dry powder mixture of Celite and Sephadex into sample wells of any shape cut to the full depth of the gel slab. Samples can then be added to the powder to form a moist firm bed of material in the wells which prevents leakage of sample from the well. The method enables the quantitative electrophoresis of many samples with widely differing concentrations and volumes without the problems of electrodecantation, loss of electrical contact through the wells, or uneven penetration of sample through the full thickness of the gel.     

Computer determination of contact stress distribution and size of weight bearing area in the human hip joint

The mathematical models and the corresponding computer program for determination of the hip joint contact force, the contact stress distribution, and the size of the weight bearing area from a standard anteroposterior radiograph are described. The described method can be applied in clinical practice to predict an optimal stress distribution after different operative interventions in the hip joint and to analyze the short and long term outcome of the treatment of various pathological conditions in the hip. A group of dysplastic hips and a group of normal hips were examined, with respect to the peak contact stress normalized by the body weight, and with respect to the functional angle of the weight bearing area. It is shown that both these parameters can be used in the assessment of hip dysplasia.     

A method for the control of the dissolved oxygen tension in microbial cultures

A method for the control of dissolved oxygen tension in growing microbial cultures is described. The apparatus consists of a motor-driven air sparge pipe which may be lowered or raised to give a variable point of entry of the air stream into the culture liquid and hence a variable gas dispersion and gas–liquid contact time. Control of the sparge pipe position is by means of a feedback control loop consisting of a dissolved oxygen probe, an on/off controller, and a reversing electric motor which drives the sparge pipe. The difficulty presented by the relatively slow response of the oxygen probe has been overcome by incorporating an adjustable rate of control action.     

Computer Determination of Contact Stress Distribution and Size of Weight Bearing Area in the Human Hip Joint

The mathematical models and the corresponding computer program for determination of the hip joint contact force, the contact stress distribution, and the size of the weight bearing area from a standard anteroposterior radiograph are described. The described method can be applied in clinical practice to predict an optimal stress distribution after different operative interventions in the hip joint and to analyze the short and long term outcome of the treatment of various pathological conditions in the hip. A group of dysplastic hips and a group of normal hips were examined, with respect to the peak contact stress normalized by the body weight, and with respect to the functional angle of the weight bearing area. It is shown that both these parameters can be used in the assessment of hip dysplasia.     

A novel and convenient self-drying system for bacterial preservation

An effective microbial preservation technology for the long-term storage of viable prokaryotic cells is described. The method combines an almost instantaneous drying step with minimal stress to the cells during drying to maximize survival on rehydration. This is achieved by contact of a microlitre aliquot of a bacterial suspension with a novel, pre-dried activated charcoal cloth based matrix contained within a re-sealable system that can then be stored. The simple methodology completely circumvents the requirement for further drying or preparation. Using this method, a standard laboratory Escherichia coli strain was successfully revived following 390 days storage at 4, 20 and 30 degrees C. Data obtained yielded approximately 20%, 6% and 0.1% viable organisms at the aforementioned temperatures, respectively, following initial inoculations of 1.1 x 10(8)/microl cells. While these figures represent a significant viability loss, there is sufficient recovery of microorganisms required for maintaining culture collections.     

Contact potential difference of cellsin vitro as a measure of hydrophilic properties of the cell membrane

Construction of an apparatus for the determination of the cell contact potential difference and the measuring method are described. The contact potential differences are attributed to the degree of hydrophobic properties of the cell surface and referred to human erythrocytes and chloroplasts.