bluuebunny/crossref_metadata_2025 huggingface dataset:
Solution Properties of Dried Rubber
Authors: Messenger T. H.
Published: February 2011

References to the properties of raw rubber dried to a point beyond that of ordinary commercial practice are very scanty. The Rubber Research Scheme is at present engaged in a comprehensive investigation into the factors governing the plasticity of raw rubber, and has found that humidity conditions during storage may greatly affect this property. Thus, storage in a dry atmosphere (over calcium chloride) leads to greater hardness (Ceylon Rubber Research Scheme, 2nd Quarterly Circ., 1929, p. 1), and storage in dry nitrogen (and it is presumed, in any dry inert medium) has a similar effect (Martin and Elliott, Ceylon Rubber Research Scheme, Quarterly Circ., 8, 7 (1931)). Staudinger and Bondy have used vacuum drying in their work on fractionating raw rubber (Ann., 488, 153 (1931)). Some years ago the writer had occasion to dry a small sample of rubber by passing over it at about 60° C. a stream of hydrogen dried by contact with phosphorus pentoxide. It was observed that alter drying the rubber was very difficult to bring into solution in benzene. This suggested the experiments described in the present note, which were initiated to examine the effect of thorough drying on the solution properties of raw rubber.
The Preparation of Chlorinated Rubbers from Latex. Hypochlorination and Chlorination Processes
Authors: Bloomfield G. F. , Farmer E. H.
Published: February 2011

With the view of extending the field of application of rubber latex, it has been considered desirable to study the behavior of this material toward various chemical reagents. Owing to the colloidal nature of latex the choice of reagent is considerably restricted; acids and many salts (especially those of bivalent and tervalent metals) produce coagulation, while alkaline reagents may cause creaming and aggregation of the particles. It is known that with the aid of certain stabilizers (e. g., saponin or casein) a stable acid latex may be obtained, but this is in general only stable over a limited range of pH values and is not stable to heat; moreover the stabilizer itself is prone to attack by the chemical reagent introduced. As would be anticipated from the foregoing considerations, the direct introduction of chlorine into latex immediately causes coagulation. Ellis and Boehmer (U. S. Patent 1,544,535) appear to have achieved some measure of success in chlorinating latex by using liquid chlorine under pressure, but the products obtained in different operations varied considerably in their properties.
Mechanism of Rubber Aging
Authors: Johnson Bernard L. , Cameron Frank K.
Published: February 2011

The position of the diffraction lines obtained on x-ray photographs of rubber does not change upon aging the rubber in the oven at 70° C. for 10 days. However, the intensity of the lines decreases as the aging time is increased. The increased elongation needed to produce fibering in aged rubber is considered necessary to expel the increased concentration of lower polymers, introduced by depolymerization during aging, from the crystalline aggregates or fibers allowing the latter to diffract the x-rays. Oxidation might also produce the same effect by the formation of obstacles to the stretching out of tangled molecules or micelles. The rate of depolymerization upon aging vulcanized rubber in the oven at 70° C. is studied, and a curve of the elongation at which the crystalline modification first appears is plotted against the time of aging. The same general curve is obtained for rubber both with and without phenyl-β-naphthylamine, indicating that an antioxidant such as phenyl-β-naphthylamine does not affect the rate of depolymerization of rubber or the elongation necessary to produce fibering in aged rubber.
Accelerators Derived from Piperidine
Authors: Philpott M. W.
Published: February 2011

Before the year 1913 piperidine was a compound of little more than academic interest and seldom to be found in considerable quantities outside the chemical laboratory. At about that time it became known that many organic bases, and in particular, piperidine and its homologs, had the effect of accelerating the vulcanization of rubber. Had piperidine then been available at a reasonable price, there is no doubt that large quantities would have been absorbed by the rubber industry. Apart from the high cost of the material, however, piperidine and other bases were not free from the objection that they were volatile and unpleasant to handle in the ordinary mixing process. In the light of modern standards, the degree of acceleration imparted by these bases would be regarded as being of a low order. In those days, however, the effect had a considerable practical significance. In attempting to make use of these bodies in a more convenient form, it was subsequently shown that the compounds formed by the reaction of carbon disulfide with aliphatic amines had an accelerating effect that was much more intense than that of the amine itself. In particular, the product obtained from the reaction of piperidine with carbon disulfide, namely, piperidyl pentamethylenedithiocarbamate (P.P.D.), was found to have exceptionally useful properties. It is probably true to say that this product was the first ultra-accelerator to acquire commercial importance.
The Swelling of Latex
Authors: Evers F.
Published: February 2011

The swelling of solid substances is a phenomenon which has been known for a long time, and extended investigations have been made on its nature. On the other hand the title of the present work may appear to be incongruous, for there has been in the past no evidence that liquids have any tendency to swell. At least the mutual action of two liquids has been spoken of, not as a swelling, but only as a partial mixing, i. e., as an equilibrated dispersion. Nevertheless, under certain conditions latex undergoes actual swelling. A reference to the works of Hauser and of earlier investigators on the morphology and composition of latex will show that the colloidal condition of the solid phase of latex is responsible for its remarkable behavior with hydrocarbons. Latex represents a dispersion of rubber in a serum. The rubber, in the form of latex globules, is surrounded by a layer of adsorbed protein. Besides salts and sugars, the serum contains protein. This complex composition causes the remarkable phenomenon of swelling of latex with hydrocarbons. A few years ago the author dealt with this phenomenon in a brief way. In the present work a few observations on experiments on the swelling of latex are described. The results of the investigation show that swelling in ammoniacal latex depends upon the swelling of a layer of rubber in the boundary surface.
The Vulcanization Process and the Reinforcement of Rubber
Authors: Twiss D. F.
Published: February 2011

The results above generally support the view that vulcanization and reinforcement are akin, and that in due time other convenient reactions than those produced by sulfur and selenium (or sulfur chloride), with rubber as the medium, will be available for both purposes. Furthermore, in that it indicates directions for future research, the “dispersion theory” of vulcanization still clearly justifies its existence.
The Use of Rubber in Paint Vehicles
Authors: Stevens H. P. , Heaton Noel
Published: February 2011

The fact that raw rubber swells and eventually dissolves with stirring in a number of solvents to yield a viscous, sticky solution naturally led to attempts to utilize this material for the preparation of paints and for the manufacture of adhesive and calking compounds like marine glue. It must be remembered that the raw rubber of the early days was not usually Hevea, but of lower grade containing much resin, and perished or deteriorated hydrocarbon, so that the product in a solvent was more sticky and less viscous than that which we should have in mind today. But whatever the grade, the viscosity of rubber solutions is a disadvantage, and has proved the main obstacle to the utilization of rubber in paints today. Apart from this drawback, quite a number of those technologists who experimented with rubber in paints were too optimistic as to the improvement likely to result. To many the word rubber sums up a material of “elastic” properties; and having great resistance to penetration by moisture and aqueous reagents generally, all desirable properties for a paint film; hence a proportion of rubber might be expected to impart added elasticity and impermeability. Such, however, is not the case. Complete incorporation of rubber to produce a homogeneous film is necessary to provide increased elasticity, while on the other hand rubber is not water-resistant unless vulcanized, and as vulcanization renders the rubber insoluble it cannot be used in this form. The prevalent idea that if a film of raw rubber were applied to a surface in the same manner as paint it should yield a moisture-proof coating is entirely erroneous, that is, using the word paint in the ordinary sense. it is possible to utilize rubber in this manner by compounding a solution of latex and applying the mixture to the surface to be coated, subsequently heating sufficiently to vulcanize, preferably to the ebonite state. By such means a water-resisting layer is obtained, but the process is only adaptable in special circumstances, and the materials are not of the class of paint which is now being considered.
Fibering of Rubber. Time Lag and Its Relation to Rubber Structure
Authors: Long John D. , Singer William E. , Davey Wheeler P.
Published: February 2011

FOR several years it has been known that in the unstretched condition ordinary rubber acts toward x-rays like an amorphous material, but that, when it is sufficiently stretched, it acts toward the rays like a fibrous material. In 1931 Acken, Singer, and Davey (1) reported that at room temperature a time interval was required to build up the fibrous structure in cyclically stretched rubber. Investigation showed that the time-lag effect could not be accounted for in terms of a temperature change during the act of stretching. Even if all the mechanical energy of stretching were instantaneously changed into sensible heat, the temperature of the rubber sample could not have been increased momentarily by more than 5.2° C., whereas the fibering of rubber continuously stretched at 420 per cent elongation could be demonstrated up to a temperature of 47° C. Experimentally no temperature rise greater than 1.0° C. could be found in the samples used. Since the time-lag effect appeared, therefore, to be a real effect, it seemed worth while to study it in detail. It is the purpose of this paper to report: (1) typical data on the effects on the time lag, of temperature, previous temperature history, mechanical working and aging, time of relaxation, time of stretch, and rate of stretch; and (2) the relation of these results to the possible structure of the rubber fiber.
A Shearing Disk Plastometer for Unvulcanized Rubber
Authors: Mooney Melvin
Published: February 2011

AN IDEAL plastometer for unvulcanized rubber would give a precise measurement of plasticity, would complete a measurement in 30 seconds or less, and would be sufficiently simple in operation to be used by an unskilled mill-hand. In an effort to develop such an instrument, a number of instruments, operating on a variety of different principles, were built and tried out; but none was found that would satisfy all the above criteria. Precision being considered a matter of primary importance, it was then felt that the only alternative was to develop a plastometer that would be as simple and as quick in operation as it could be and still remain accurate. The shearing plastometer described below was the result.
The Structure of Gutta-Percha Based on Studies with Electron Rays
Authors: Bruni G. , Natta G.
Published: February 2011

Among the natural organic compounds with high molecular weights which have been the object of roentgenographic investigations with a view to determining their intimate constitution, rubber and other hydrocarbons of similar constitution such as gutta-percha and balata have been extensively studied in recent years. The results obtained with these substances by x-ray methods have however not been so complete and reliable as in the case of other products with high molecular weights, such as cellulose, found in nature in ramie and in certain vegetable fibers in forms which are particularly well oriented, which is of enormous advantage in structural investigations. Nevertheless, the roentgenographic results on rubber are of the greatest interest because from them it is possible to show that the molecules of rubber are oriented when the rubber is stretched or frozen, so that it can be proved that under these special conditions it has a sort of crystalline structure which is characterized by definite identity periods. The determination of the identity period in the direction of the fibers, which is 8.1 A. U., is particularly reliable.
The Viscosity of Latex
Authors: Bary Paul
Published: February 2011

Latex, like most emulsions, has complex properties which make its use at times difficult because of somewhat unexpected phenomena which take place within the mass. The properties of this material, whose usage is spreading more and more, are therefore of practical interest, and this has led us to publish the results of some investigations on the viscosity of latex and the conclusions which seemed to be justified by these experiments. The viscosity of a normal latex containing 38 per cent of rubber is about 4.6 times as great as that of water. This is true of a latex containing a little ammonia, such as the grades which can be purchased in France. The same latex, concentrated to 60 per cent, or “Jatex,” is almost 42 times as viscous as water, i. e., more than 10 times as viscous as 38 per cent latex. Moreover, if latex of different concentrations is prepared by dilution of 60 per cent latex, it is found that the viscosities are those given in the accompanying table, expressed as relative viscosities, based on the viscosity of water.
Some Observations on Accelerator Practice and Modern Compounding
Authors: Davies R. C.
Published: February 2011

In the last twenty-five years a number of complex organic compounds have been developed and patented for the purpose of accelerating the vulcanization of rubber. Really serious bulk usage throughout the trade, however, did not commence until after the war. Research in this field raced ahead of manufacturing progress and brought out accelerators which were so active that they were almost unusable. There are now accelerators which are more than sufficient for the needs of the moment. They cover all ranges of conditions, such as slow, medium slow, semi-fast, semi-ultra, ultra, and super-ultra accelerators. In addition there are modifications for delayed action, quick start, flat peak, high tensile, and superflexing; also accelerators which will cure without heat and others which will cure without added sulfur. In view of the publicity indulged in by the vendors, one might almost feel compelled to change one's accelerators every week. Rationalization is as necessary in the use of accelerators as in the use of fillers. In the wise use of accelerators it is necessary to make a careful selection of only a few which function best in the temperature and process range of any particular manufactures.
Colloidal Changes during Rubber Vulcanization
Authors: Williams Ira
Published: February 2011

RUBBER is colloidal in nature and colloidal phenomena should be expected to play a part in the decrease of plasticity which is recognized as vulcanization. The elasticity of vulcanized and unvulcanized rubber is substantially the same (23), and it is probable that elasticity is a function of the molecule while plasticity is a function of the state of aggregation. Many authors have suggested that either disaggregation or depolymerization is one step in vulcanization (1, 8, 15, 16, 19). Other authors believe that aggregation or polymerization is a factor (2, 4, 6, 9, 10, 13, 14, 18, 19, 21, 22). In many cases it is probable that the term “polymerization” or “depolymerization” is used loosely and is not intended to involve a change in unsaturation. Ostromislensky (12), Stevens (17), and Twiss (20) have suggested that vulcanized rubber contains the reaction product of rubber and sulfur dispersed through the rubber as fine particles or threads. Feuchter (5) suggests a similar although somewhat more complicated system which includes accelerator. Whitby (21) concludes from his experiments with drying oils that accelerators act on rubber containing combined sulfur to produce gelation or polymerization. Stevens and Stevens (18) have milled zinc oxide and accelerator into acetone-extracted vulcanized rubber and find that heating produces further vulcanization.
New Results on the Ozone Decomposition of Natural Rubber and of Sodium Butadiene Rubber
Authors: Pummerer R.
Published: February 2011

The method of Harries for the ozone cleavage of unsaturated organic compounds has shown its first important results in the case of rubber. Surprising as it may seem, however, there has been no attempt until now to follow the course of this reaction by bromine titration. When this is carried out, a very surprising result is obtained. It was to be expected that, corresponding to the addition of ozone to the double bonds, there would be an equivalent decrease in the bromine titre. However, such is not the case. If a one per cent solution of rubber in chloroform is ozonized at 0° and samples are removed from time to time and titrated dropwise with bromine solution until the yellow coloration persists for 10 minutes, it is found that the consumption of bromine for the first one to two hours undergoes no essential decrease as a result of the introduction of ozone. If the titration is continued, a rather rapid diminution begins at the time when free ozone can be detected in a potassium iodide solution placed beyond the ozone vessel. The curve then descends sharply to zero. Closer study of the process by the titration method of MacIlhiney, which also makes it possible to collect the hydrogen bromide formed, has shown us that in the case of rubber the apparent initial constancy of the bromine consumption is explained by the fact that there is an ozonide replaceable by bromine, and accordingly that the bromine number represents substitution and addition, whereas under the above conditions (10 min. at 0° C.) the original rubber solution in chloroform shows only addition. The ozonide which reacts with bromine may be termed a primary ozonide, and that which is formed later and is stable toward bromine may be called an isozonide. This name originated with Staudinger, who pointed out nine years ago that in the ozonization of olefins it is possible that “molozonides,” or, as we now say primary ozonides, of very unstable type are first formed, which still contain the added molecule of ozone (Formula I) whereas the ordinary end products of ozonization are formed by rearrangement and are to be called isozonides (Formula II). This was concluded by Staudinger from the known behavior of the ozonide in the reduction, which never yields 1,2-glycol but a cleavage of the carbon chain instead. The formation of polymeric ozonides together with quite stable monomers, which are not converted into polymers, is further evidence of this.
Surface Cracking of Vulcanized Rubber
Authors: Turner H.
Published: February 2011

Surface cracking of vulcanized rubber has been the subject of a number of publications, to which reference has been made in an excellent summary by Evans (Trans. Inst. Rubber Ind., 5, 442 (1930)). Others have followed since that summary appeared and reference will be made to some of them. Certain conditions are commonly believed to be essential for cracking to take place. Van Rossem and Talen (Kautschuk, 7, 79, 115 (1931)), as a result of a comprehensive and valuable investigation of the subject, came to the conclusion that two factors are necessary, (1) stretching of the rubber, and (2) the action of ozone. The first conclusion, as is pointed out, is in agreement with the work of Haushalter (India Rubber J., 70, 897 (1925)) and of Kearsley (Rubber Age (New York), 27, 649 (1930)). Williams (Ind. Eng. Chem., 18, 367 (1926)) had previously attributed cracking to ozone, and stated that it had no effect on unstrained rubber. Shepard, Krall, and Morris (Ibid., 615) also found no cracking of unstretched samples when exposed to sunlight for months. That stretching is always necessary is not accepted by Merz (Kautschuk, 8, 73 (1932)), who conducted experiments with “collapsible boat materials” and obtained cracking on exposing the samples out of doors in an unstretched condition.
Studies on the Nature of the Action of Organic Accelerators for Rubber Vulcanization. VII. The Effect of Heat on the Surface Tension of Rubber Solutions
Authors: Shimada Keiichi
Published: February 2011

In the previous paper on the effect of heat on the viscosity of rubber solutions (J. Rubber Soc., Japan,3, 413 (1931)), the present author suggested that the reduction in viscosity of dilute solutions of rubber on heating is probably a sign of depolymerization and not of physical disaggregation. In this report, the surface tension of rubber solutions has been investigated in an attempt to elucidate the effect of heat on rubber solutions and to draw some more definite conclusions. It should be possible, in the author's opinion, to detect depolymerization of rubber molecules by observing the surface tension variations of rubber solutions on heating, since the depolymerization of rubber would produce molecules differing widely in physical and chemical properties from the polymerized substance, and having most probably a different effect on the surface tension of the solution, whereas disaggregation of the dissolved substance in a solution is likely to produce no change in the surface tension, as aggregation implies merely coalescing particles to form larger groups, with no change in molecular species. it is possible that in solution a dynamic equilibrium exists between the particles and the aggregates, though the actual concentration of disaggregated material may be small. The results of the present work offer support to the theory that the effect of heat on dilute rubber solutions involves chemical depolymerization, that is, a breaking up of the long rubber molecules into shorter ones.
PCA-Combined Receive Antenna Selection for MMSE V-BLAST in Correlated Channels
Authors: Hu Chia-Chang , Wang Chi-Tsung
Published: February 2011

A computationally efficient receive antenna subset selection in conjunction with the principal component analysis (PCA) is proposed for the minimum mean square error (MMSE) V-BLAST systems in correlated channels. This proposed PCA-combined antenna subset selection is capable of sustaining system performance and reducing complexity burden in signal processing and hardware cost.
Autoadaptive Algorithm for the Stacking-Level Estimation of Membranes in TEM Images
Authors: Hermann G. , Coudray N. , Karathanou A. , Buessler J. L. , Urban J. P.
Published: February 2011

This paper introduces an original algorithm for the labeling of the regions of a partitioned image according to the stacking level of membranes in transmission electron microscopy (TEM) images. Image analysis of membrane protein TEM images represents a particular challenging task because of the important noise and heterogeneity present in these images. The proposed algorithm adapts automatically to fluctuations and gray level ranges characterizing each membrane stacking level. Some information
about the organization of the objects in the images is introduced as prior knowledge. Three types of qualitative and quantitative
experiments have been specifically devised and implemented to assess the algorithm.
Multiple Stafne Bone Defects: A Rare Entity
Authors: Aguiar Luciana Barreto Vieira , Neves Frederico Sampaio , Bastos Luana Costa , Crusoé-Rebello Iêda , Ambrosano Glaucia Maria Bovi , Campos Paulo Sérgio Flores
Published: February 2011

Stafne bone defects (SBDs) are generally located in the lingual cortex, close to the mandibular angle. We report the occurrence of multiple SBDs in an asymptomatic patient, a 60-year-old man, referred to a radiology clinic to undergo examination for the purpose of implant planning. The case of multiple SBD presented here, probably the first reported in the literature, reinforces the hypothesis that some cases of SBD may be the result of a focal failure during the ossification of the mandible.
Silver–Polymer Composite Stars: Synthesis and Applications
Authors: Homan Kimberly A. , Chen Jeffrey , Schiano Adriane , Mohamed Mona , Willets Katherine A. , Murugesan Sankaran , Stevenson Keith J. , Emelianov Stanislav
Published: February 2011

Colloidal “silver stars” were synthesized upon poly(lactic‐co‐glycolic) acid nanosphere templates via a facile two‐step silver reduction method. Myriad dendrimer‐like Ag star morphologies were synthesized by varying the amount of poly(vinyl alcohol) and trisodium citrate used during silver reduction. Scanning electron microscopy studies revealed that star‐shaped silver–polymer composites possessing nanoscopic, fractal morphologies with diameters ranging from 500 nm to 7 μm were produced. These composites have broad applications from antibacterial agents to catalysis; two such applications were tested here. Surface‐enhanced Raman spectroscopy (SERS) studies showed multiple hot spots of SERS activity within a single star. Electrochemical catalysis experiments demonstrated the feasibility of using the silver stars instead of platinum for the oxygen reduction reaction in alkaline fuel cells.
Synthesis and Characterization of Acceptor‐Substituted Oligothiophenes for Solar Cell Applications
Authors: Mishra Amaresh , Uhrich Christian , Reinold Egon , Pfeiffer Martin , Bäuerle Peter
Published: February 2011

We report the synthesis of novel acceptor‐substituted oligothiophenes and their application in m‐i‐p type planar heterojunction solar cells. Optical absorption spectra and electrochemical properties of the dyes are investigated. The determined energy levels of these dyes suggest that they should be ideal for use in heterojunction solar cells. We further investigate the influence of acceptor groups on the device performance by introducing 1,1‐dicyano‐2‐methyl‐vinyl and 1,1‐dicyano‐2‐phenyl‐vinyl groups, respectively, as acceptor units. Photovoltaic devices incorporating these dyes show an open circuit voltage of up to 0.96 V and power conversion efficiencies in the range of 1.5–3.0% under full sun illumination (simulated AM 1.5G sunlight, 100 mW cm−2).
Mechanisms and clinical relevance of TRAIL‐triggered responses in the synovial fibroblasts of patients with rheumatoid arthritis
Authors: Audo Rachel , Calmon‐Hamaty Flavia , Baeten Dominique , Bruyer Angelique , Combe Bernard , Hahne Michael , Morel Jacques
Published: February 2011

Objective

Results of studies in mice suggest a protective role for TRAIL in arthritis. The aim of this study was to investigate the role of TRAIL in patients with rheumatoid arthritis (RA).

Methods

In the present study, we compared RA fibroblast‐like synoviocytes (FLS) that were resistant or sensitive to TRAIL‐induced apoptosis and the expression of TRAIL receptors in these cells, and also investigated the clinical features of the patients from whom the FLS were derived. Furthermore, we evaluated the levels of TRAIL and its soluble decoy receptor osteoprotegerin (OPG) in patients with RA, patients with osteoarthritis (OA), and patients with spondylarthritis (SpA).

Results

Sensitivity to TRAIL‐induced apoptosis varied in FLS from different patients, and the severity of disease in patients with RA was inversely correlated with the susceptibility of their FLS to TRAIL‐induced apoptosis. TRAIL‐sensitive cells expressed significantly lower levels of TRAILR‐1, and silencing of TRAILR‐1 increased TRAIL‐induced apoptosis in RA FLS. TRAIL levels were elevated in the arthritic joints of patients with established RA, and TRAIL levels in the synovial fluid of these patients were elevated compared with levels in the synovial fluid of patients with OA or SpA. At baseline, a low OPG‐to‐TRAIL ratio in the sera of patients with early RA was associated with a better evolution of disease activity, but high serum levels of TRAIL at followup were associated with joint damage.

Conclusion

These findings suggest that TRAIL has a dual role in RA, and that the resistance of RA FLS to TRAIL‐induced apoptosis is associated with a disease‐promoting activity of TRAIL in RA.
A novel N‐ethyl‐N‐nitrosourea–induced mutation in phospholipase Cγ2 causes inflammatory arthritis, metabolic defects, and male infertility in vitro in a murine model
Authors: Abe Koichiro , Fuchs Helmut , Boersma Auke , Hans Wolfgang , Yu Philipp , Kalaydjiev Svetoslav , Klaften Matthias , Adler Thure , Calzada‐Wack Julia , Mossbrugger Ilona , Rathkolb Birgit , Rozman Jan , Prehn Cornelia , Maraslioglu Miriam , Kametani Yoshie , Shimada Shin , Adamski Jerzy , Busch Dirk H. , Esposito Irene , Klingenspor Martin , Wolf Eckhard , Wurst Wolfgang , Gailus‐Durner Valerie , Katan Matilda , Marschall Susan , Soewarto Dian , Wagner Sibylle , de Angelis Martin Hrabě
Published: February 2011

Objective

It is difficult to identify a single causative factor for inflammatory arthritis because of the multifactorial nature of the disease. This study was undertaken to dissect the molecular complexity of systemic inflammatory disease, utilizing a combined approach of mutagenesis and systematic phenotype screening in a murine model.

Methods

In a large‐scale N‐ethyl‐N‐nitrosourea mutagenesis project, the Ali14 mutant mouse strain was established because of dominant inheritance of spontaneous swelling and inflammation of the hind paws. Genetic mapping and subsequent candidate gene sequencing were conducted to find the causative gene, and systematic phenotyping of Ali14/+ mice was performed in the German Mouse Clinic.

Results

A novel missense mutation in the phospholipase Cγ2 gene (Plcg2) was identified in Ali14/+ mice. Because of the hyperreactive external entry of calcium observed in cultured B cells and other in vitro experiments, the Ali14 mutation is thought to be a novel gain‐of‐function allele of Plcg2. Findings from systematic screening of Ali14/+ mice demonstrated various phenotypic changes: an abnormally high T cell:B cell ratio, up‐regulation of Ig, alterations in body composition, and a reduction in cholesterol and triglyceride levels in peripheral blood. In addition, spermatozoa from Ali14/+ mice failed to fertilize eggs in vitro, despite the normal fertility of the Ali14/+ male mice in vivo.

Conclusion

These results suggest that the Plcg2‐mediated pathways play a crucial role in various metabolic and sperm functions, in addition to initiating and maintaining the immune system. These findings may indicate the importance of the Ali14/+ mouse strain as a model for systemic inflammatory diseases and inflammation‐related metabolic changes in humans.
Disease named entity recognition using semisupervised learning and conditional random fields
Authors: Suakkaphong Nichalin , Zhang Zhu , Chen Hsinchun
Published: February 2011

Information extraction is an important text‐mining task that aims at extracting prespecified types of information from large text collections and making them available in structured representations such as databases. In the biomedical domain, information extraction can be applied to help biologists make the most use of their digital‐literature archives. Currently, there are large amounts of biomedical literature that contain rich information about biomedical substances. Extracting such knowledge requires a good named entity recognition technique. In this article, we combine conditional random fields (CRFs), a state‐of‐the‐art sequence‐labeling algorithm, with two semisupervised learning techniques, bootstrapping and feature sampling, to recognize disease names from biomedical literature. Two data‐processing strategies for each technique also were analyzed: one sequentially processing unlabeled data partitions and another one processing unlabeled data partitions in a round‐robin fashion. The experimental results showed the advantage of semisupervised learning techniques given limited labeled training data. Specifically, CRFs with bootstrapping implemented in sequential fashion outperformed strictly supervised CRFs for disease name recognition. The project was supported by NIH/NLM Grant R33 LM07299–01, 2002–2005.
Multiple use of an industrial‐distributed control system in control engineering education
Authors: Dittmar Rainer , Kahlcke Thomas
Published: February 2011

The paper demonstrates how a four‐tank laboratory process equipped with a modern distributed control system (DCS) is used in different control engineering laboratories for the undergraduate and graduate levels. This includes the utilization of commercial tools for DCS engineering as well as the design and commissioning of traditional and advanced control solutions. Using the same pilot plant and control system in different modules lowers the costs, allows the reutilization of results and enables an efficient laboratory organization. It also supports the process of learning the inner context of different process control related subjects. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 313–321, 2013
Flow cytometric osmotic fragility—An effective screening approach for red cell membranopathies
Authors: Warang Prashant , Gupta Maya , Kedar Prabhakar , Ghosh Kanjaksha , Colah Roshan
Published: February 2011

Background:

Among the red cell membrane disorders, hereditary spherocytosis (HS) is one of the most common causes of inherited hemolytic anemia. The aim of this study was to compare the flow‐cytometric approach for screening of red cell membrane disorders based on osmotic fragility with the eosin‐5‐maleimide (E5′M) dye test. A group of β‐thalassemia heterozygotes were also studied.

Methods:

A red cell suspension was spiked with deionized water during acquisition and the count of residual red cells measured sequentially in real‐time using flow cytometry. Fluorescence intensity of red cells stained with eosin‐5‐maleimide was also measured.

Results:

The hereditary spherocytosis (HS) group showed significantly decreased percentage residual red cells (9.31% ± 3.75%) (P = 0.0091) whereas the β‐thalassemia group showed a significant increase (93.56% ± 12.98%) (P = 0.0008) compared to the normal control group (46.26% ± 11.33%). The cut off value of the flow cytometric osmotic fragility (FCM OF) test for red cell membrane disorders was 23.59% giving a sensitivity of 100% and specificity of 98%.

Conclusions:

The advantages of the FCM OF test are that it is quantitative, time effective and requires only deionized water for the measurement of osmotic fragility. It could be an effective first line screening approach for red cell membrane disorders in hematology laboratories where a flow cytometer is available. © 2011 International Clinical Cytometry Society
Improved compensation of the fluorochrome AmCyan using cellular controls
Authors: DiGiuseppe Joseph A. , Cardinali Jolene
Published: February 2011

Background:

Implementation of polychromatic flow cytometry in the clinical laboratory often requires the use of newer fluorochromes, with which experience may be comparatively limited. In the course of implementing polychromatic flow cytometry in our laboratory, we have observed significant differences in compensation values derived for the violet‐excited dye, AmCyan, when cells rather than a commercially available set of polystyrene microparticles (BD CompBeads) are used as compensation controls.

Methods:

Compensation values were calculated for AmCyan and several other fluorochromes using the BD CompBeads Set according to the manufacturer's protocol, and using unstained and singly stained lymphocytes as compensation controls.

Results:

When the BD CompBeads Set was used to determine compensation values, spillover from AmCyan into V450 was overcompensated, while spillover from AmCyan into FITC was undercompensated. In contrast, when compensation values were calculated using unstained and singly stained lymphocytes, spillover into V450 and FITC from cells stained brightly with AmCyan‐conjugates was compensated appropriately. Although significant differences were observed in the compensation of spillover from AmCyan into V450 and FITC using cells rather than the BD CompBeads Set as compensation controls (P < 0.0001, two‐tailed Wilcoxon signed‐rank test), such differences were not observed in control experiments using fluorochromes excited by the blue (FITC and PE) or red (APC) lasers.

Conclusion:

Improved compensation of the violet‐excited dye, AmCyan, is obtained when cells rather than the BD CompBeads Set are used as compensation controls. © 2011 International Clinical Cytometry Society
Cell screening assay for identifying inhibitors of eosinophil proliferation
Authors: Kempe‐Dustin Jessica J. , Aboul‐Fadl Tarek , Christensen Clarissa , Palais Robert , Parsawar Krishna , Gleich Gerald J. , Wagner Lori A.
Published: February 2011

The purpose of this study was to develop a cell‐based screening assay for identification of small molecules for the treatment of asthma. Eosinophils are leukocytes that contribute to the pathology of asthma. Lidocaine inhibits interleukin‐5 (IL‐5)‐mediated survival and activation of human eosinophils, and it is able to replace inhaled glucocorticoids for the treatment of asthma; however, lidocaine has many side effects, including anesthesia. Therefore, a collection of commercial and novel, synthesized lidocaine analogues were investigated for inhibitory activity of the IL‐5‐stimulated proliferation of TF‐1 cells, a CD34+, cytokine‐dependent, erythroleukemic cell line model for eosinophil growth. Among 74 investigated compounds, 10 were more potent inhibitors of cell proliferation than lidocaine (average IC50 = 223 µM), with IC50 values ranging within 1–119 µM. This cell‐based assay is an effective method for screening chemical compounds and has revealed promising lead compounds for the treatment of asthma. Drug Dev Res 72: 353–360, 2011. © 2011 Wiley‐Liss, Inc.
Improved in vitro dissolution parameters and in vivo hypolipidemic efficiency of atorvastatin calcium through the formation of hydrophilic inclusion complex with cyclodextrins
Authors: Hussein Amal K. , Ibrahim Mohamed A. , Amin Mohamed A. , Ahmed Osama A.A. , Afouna Mohsen I.
Published: February 2011

An aim of the present study was to improve the dissolution of the inherently low water solubility hypolipidemic agent, Atorvastatin calcium (ATC), through the preparation and characterization of ATC with cyclodextrins (CDs) inclusion complexes employing different techniques. A second goal was to study the in vivo hypolipidemic efficacy of ATC‐complexes with enhanced dissolution characteristics. Inclusion complexation of ATC with β‐cyclodextrin (β‐CD) and hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) was evaluated in aqueous and solid states. ATC formed inclusion complexes with β‐CD and HP‐β‐CD depending to a great extent upon ATC ionization state. Evaporation and freeze‐drying were the most efficient techniques to achieve complexation. In contrast, kneading was an inefficient tool to create true inclusion complexes, which could reflect the hindrance of drug–CDs interactions in the semisolid medium. The ATC:CD ratio of 1:2 showed better dissolution characteristics compared to a 1:1 ratio. Moreover, the in vivo hypolipidemic activities of ATC‐CDs (β‐CD and HP‐β‐CD) complexes were greater (P<0.05) than the other investigated formulations. Thus the nature of the carrier did not play a critical role in the dissolution characteristics of the inclusion system. In contrast, the carrier molar ratio, and the employed complexation technique were found to be key factors in enhancing the ATC dissolution rate, yielding performances as well as the in vivo hypolipidemic efficacies. Drug Dev Res 72: 379–390, 2011. © 2011 Wiley‐Liss, Inc.
Synthesis of 2′,3′‐Modified Carbocyclic L‐Nucleoside Analogues
Authors: Jessel Sönke , Meier Chris
Published: February 2011

New divergent approaches to 2′,3′‐modified carbocyclic L‐nucleoside analogues starting from enantiomerically pure (1R,2S)‐ or (1S,2R)‐2‐(benzyloxymethyl)cyclopent‐3‐enol are described. In the key step, stereochemically pure cyclopentanols were condensed with N3‐protected thymine through a modified Mitsunobu protocol. Moreover, several routes to different cyclopentanol derivatives, to prepare carbocyclic L‐2′,3′‐didehydro‐2′,3′‐dideoxynucleosides (L‐d4N), L‐2′,3′‐dideoxynucleosides (L‐ddN), and L‐ribonucleosides are reported.
Mycelium‐bound lipase production from Aspergillus niger MYA 135, and its potential applications for the transesterification of ethanol
Authors: Colin Verónica Leticia , Baigorí Mario Domingo , Pera Licia María
Published: February 2011

The potential biotecnological applications of both constitutive and inducible lipase sources from Aspergillus niger MYA 135 were evaluated. To this end, the effect of environmental conditions on mycelium‐bound lipase production from this strain was studied, when cultured either in the absence or presence of 2% olive oil. It was previously reported that mycelium‐bound lipase from Aspergillus niger MYA 135 possess high stability in reaction mixtures containing ethanol; which could be especially important for their use in biodiesel synthesis. In this connection, the performance of the lipase sources produced in the transesterification of ethanol using p‐nitrophenyl palmitate as acyl donor was also explored.

Under our assay conditions, hydrolytic and synthetic activity of the mycelia produced in the absence or presence of olive oil were not highly correlated. While the hydrolytic activity was strongly increased by the addition of lipid to the culture medium, the best performance in the transesterification reactions of ethanol were associated with mycelia produced in absence of olive oil. Interestingly, the supplementation of the culture medium with Fe+3 increased the transesterification activity by 71%, as compared to the activity previously reported for this strain. Therefore, the constitutive lipase sources from Aspergillus niger MYA 135 are considered to be promising for industrial biodiesel‐fuel production. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efflux mediated adaptive and cross resistance to ciprofloxacin and benzalkonium chloride in Pseudomonas aeruginosa of dairy origin
Authors: Pagedar Ankita , Singh Jitender , Batish Virender K.
Published: February 2011

The present study was undertaken to investigate the role of efflux pump activity (EPA) in conferring adaptive and cross resistances against ciprofloxacin (CF) and benzalkonium chloride (BC) in dairy isolates of Pseudomonas aeruginosa. Biofilm formation potential was correlated with development of adaptive resistance in originally resistant strains. Irrespective of parent strains's susceptibility, isolates developed substantial adaptive resistance against CF and BC. Significant difference was observed in ability of non resistant isolates to develop adaptive resistance against CF and BC (P < 0.02) and subsequent cross resistance. EPA was quantified using EtBr (Ethidium Bromide) model and its role was more prominent [confirmed by its inhibition using efflux pump inhibitor (EPI) 2,4‐dinitrophenol (DNP)], in conferring adaptive resistance (P = 0.147) than cross resistance (P = 0.343). Reduction in adaptive resistances due to EPI was more evident in originally non resistant strains, which reaffirms EPA as probable mechanism of adaptive resistance. The present study perhaps first of its kind, suggests an active role of EPA in conferring adaptive and cross resistances in food related P. aeruginosa isolates and supports reverse hypothesis that antibiotic‐resistant organisms eventually become tolerant to other antibacterial agents as well. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative evaluation of prokaryotic 16S rDNA clone libraries and SSCP in groundwater samples
Authors: Larentis Michael , Alfreider Albin
Published: February 2011

A comparison of ribosomal RNA sequence analysis methods based on clone libraries and single‐strand conformational polymorphism technique (SSCP) was performed with groundwater samples obtained between 523–555 meters below surface. The coverage of analyzed clones by phylotype–richness estimates was between 88–100%, confirming that the clone libraries were adequately examined. Analysis of individual bands retrieved from SSCP gels identified 1–6 different taxonomic units per band, suggesting that a single SSCP band does often represent more than one single prokaryotic species. The prokaryotic diversity obtained by both methods showed an overall difference of 42–80%. In comparison to SSCP, clone libraries underestimated the phylogenetic diversity and only 36–66% of the phylotypes observed with SSCP were also detected with the clone libraries. An exception was a sample where the SSCP analysis of Archaea identified only half of the phylotypes retrieved by the clone library. Overall, this study suggests that the clone library and the SSCP approach do not provide an identical picture of the prokaryotic diversity in groundwater samples. The results clearly show that the SSCP method, although this approach is prone to generate methodological artifacts, was able to detect significantly more phylotypes than microbial community analysis based on clone libraries. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A phylogenetic comparison of urease‐positive thermophilic Campylobacter (UPTC) and urease‐negative (UN) C. lari
Authors: Hirayama Junichi , Tazumi Akihiro , Hayashi Kyohei , Tasaki Erina , Kuribayashi Takashi , Moore John E. , Millar Beverley C. , Matsuda Motoo
Published: February 2011

In the present study, the reliability of full‐length gene sequence information for several genes including 16S rRNA was examined, for the discrimination of the two representative Campylobacter lari taxa, namely urease‐negative (UN) C. lari and urease‐positive thermophilic Campylobacter (UPTC). As previously described, 16S rRNA gene sequence are not reliable for the molecular discrimination of UN C. lari from UPTC organisms employing both the unweighted pair group method using arithmetic means analysis (UPGMA) and neighbor joining (NJ) methods. In addition, three composite full‐length gene sequences (ciaB, flaC and vacJ) out of seven gene loci examined were reliable for discrimination employing dendrograms constructed by the UPGMA method. In addition, all the dendrograms of the NJ phylogenetic trees constructed based on the nine gene information were not reliable for the discrimination. Three composite full‐length gene sequences (ciaB, flaC and vacJ) were reliable for the molecular discrimination between UN C. lari and UPTC organisms employing the UPGMA method, as well as among four thermophilic Campylobacter species. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)