bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of the Heat Deterioration of Specially Prepared Natural Rubber Vulcanizates
Authors: Metz Donald J. , Mesrobian Robert B. 
Published: February 2011

Abstract
In 1949, Flory, Rabjohn, and Shaffer presented an article describing the dependence of the elastic properties of vulcanized rubber on the degree of cross-linking. In order to prepare rubber vulcanizates characterized by known degrees of cross-linkage recently developed, disazodicarboxylate vulcanizing reagents were employed. These reagents react quantitatively with rubber, one cross-linkage being introduced for each molecule of the reagent. Whereas the conventional vulcanization of rubber with sulfur and accelerators is a complex process and it does not appear possible at the present time to specify the exact number of cross-linkages present in sulfur vulcanizates, the use of disazodicarboxylate vulcanizing reagents presents an opportunity to investigate the changes that occur in the physical properties of vulcanized rubber, characterized by known degrees of cross-linkage, on exposure to oxygen at elevated temperatures. Furthermore, the effect of heat deterioration of various chemical agents commonly employed in sulfur vulcanization recipes may be investigated in a unique way by incorporating such chemical agents in the free state into natural rubber previously vulcanized by disazodicarboxylate reagents. Recent studies of the deterioration of rubber vulcanizates at elevated temperatures have been reported by several workers. In this article, the experimental methods employed to study heat deterioration involve measurements of oxygen absorption, stress relaxation, and changes of 100 per cent modulus of natural rubber vulcanized to known extents of cross-linkage by decamethylene-dismethyl azodicarboxylate.
The Flocculation of Dilute Latex by Zinc Sulfate
Authors: Thirion Pierre 
Published: February 2011

Abstract
Within a particular range of temperatures and a particular concentration of rubber, the flocculation of diluted latex by a water-soluble zinc salt is characterized by a critical amount of zinc, termed the salt index, which is necessary and sufficient to destroy abruptly the colloidal equilibrium of the dispersion. In the course of an investigation of a preliminary nature, measurements were made of the changes of the salt index as a function of the concentration and of the initial pH value of different field latexes and of two samples of latex preserved with ammonia. The influence of centrifugation and of buffering agents was likewise investigated. On a theoretical basis, the phenomenon appears to be governed to a major degree by chemical reactions of the zinc with certain substances which are either in solution in the serum or are adsorbed on the rubber particles. From the practical point of view, a systematic investigation is underway to determine whether the salt index as thus defined can be accepted as a new test of the stability of Fresh latex and preserved latex.
Contribution to the Determination of the Abrasion Resistance of Soft Vulcanized Rubber
Authors: Herzog R. , Burton R. H. 
Published: February 2011

Abstract
Of the great number of methods available for the determination of the abrasion resistance of vulcanized rubber, only a few give results which correlate at all well with actual service performance. The part played by the resilience of the rubber, the correct choice of test load, and the manner of application of this load are among the many testing conditions which are of considerable importance. Some of these conditions are considered in the present work, and a new abrasion testing machine is described.
Supplementary Report
Authors: Hommel F. 
Published: February 2011

Abstract
The leading ideas of Giese, Stein and Lauer's work may be expressed by the following statements. 1. In a rolling wheel-and-tire assembly, there are electric fields: (a) Between road and tire surface. (b) Between outside and inside tire surface. (c) Between inside tire surface and tube. (d) Between inside tire surface and rim. 2. Special attention is devoted to the so-called “inner field” between inside tire surface and tube; an attempt is made to measure and control it by suitable means. Regarding these fields it may be remarked that electrical boundary surfaces, and hence charge accumulations due to intimate contact, occur at the following points : 1. Instantaneous contact area between tire and road. 2. Points between casing and tube, especially in the flexure zone, where casing and tube may be displaced somewhat from each other. In the latter case—that of the field between casing and tube, henceforth to be called the “inner field”, the casing and tube section is to be regarded as a capacitance whose magnitude may be estimated as follows: area about 500 sq. cm., plate interval about 10−3 cm., due to elevations and depressions along casing at cords ; hence, capacitance of 5×104μμf. For very intimate contact, the plate interval may be reduced to about 10−6 cm., in which case the capacitance rises to 5×107μμf.
Chromatographic Analysis of Vulcanized Rubbers. Specific Methods for the Detection of Some Dithiocarbamate Accelerators
Authors: Parker C. A. , Berriman Joyce M. 
Published: February 2011

Abstract
Methods are described for the mutual separation and identification of six alkyl-substituted dithiocarbamates by ehromatography of their brown copper complexes on silica gel. These methods have been successfully applied to the detection of dithiocarbamates in vulcanized rubbers, and they form an extension to the scheme for the chromatographic identification of accelerators and antioxidants reported in a previous communication.
Electron Microscopy of Hevea Latex Gels
Authors: de Vries A. J. , Dalitz V. Ch 
Published: February 2011

Abstract
The use of preserved concentrated Hevea latex for the production of rubber articles has given birth, during the last decades, to a number of quite new technological methods in rubber manufacture. Starting from an aqueous rubber dispersion of low viscosity as a raw material, instead of the very tough viscoelastic solid rubber, may be advantageous in many respects. Latex technology, however, also presents its particular difficulties and drawbacks, one of which is concerned with the problem of the reinforcement of rubber. Reinforcing fillers like carbon black, which enhance the tear strength and abrasion resistance of masticated rubber, do not exhibit the same beneficial effect on the properties of rubber films cast from latex ; the same is true of all fillers if added in appreciable amounts, with the notable exception of resorcinol-formaldehyde resins formed in situ. Nevertheless, the strength of vulcanized cast films from latex is excellent in comparison with vulcanized sheets of masticated solid rubber. In order to get more insight into the factors which control the rheological and mechanical properties of wet as well as dried and vulcanized latex gels, an extensive study has been undertaken, part of which has been concerned with an elucidation of the structure of these gels by means of electron microscopy. The purpose of this paper is to describe the experimental methods for obtaining electron micrographs and to present some of the results. The rheological and mechanical properties will be discussed in forthcoming publications, one of which has appeared in print already.
Determination of Particle-Size Distribution in GR-S Latexes
Authors: Nisonoff Alfred , Messer W. E. , Howland L. H. 
Published: February 2011

Abstract
A method based on Stokes' law, involving the use of an ordinary laboratory centrifuge, is described for the determination of particle size distribution in GR-S latexes. It is shown to be valid by tests for reproducibility and by comparison with the results of light and electron microscopy. In applying the method, several unusually fluid high-solids latexes made in the pilot plant were found to be characterized by a wide distribution of particle sizes. Data on various latexes in plant production are reported.
Photoelastic Studies Concerned with Fatigue Phenomena in Rubber Articles
Authors: Angioletti Attilio 
Published: February 2011

Abstract
In every case studied, rupture caused by fatigue begins at the stressed surfaces, i.e., conforms to tension isostatics tangent to the external profile, and then extends inward. It is, therefore, necessary to restrict the deformations by surface tensile stresses within the narrowest possible limits. The photoelastic method, even with very simple means, makes it possible to confirm experimentally the existence of local deformations, and facilitates the search for improvements in the fatigue resistance of rubber articles.
Electric Measurements of Rubber-Carbon Black Systems
Authors: Kickstein Gotthold 
Published: February 2011

Abstract
The addition of active carbon black to rubber causes considerable reinforcement and, hence, improves the serviceability of rubber products. On the other hand, electrically conductive carbon black imparts to rubber-carbon black mixtures a strongly polar character which is reflected in the electric constants. The specific direct current-resistance is frequently changed by several decimal powers by the addition of carbon black. With very small concentrations of carbon black, the resistance at first increases somewhat, probably as a result of union of ions by the carbon black. With somewhat greater concentrations (over 10–15 per cent by weight), the resistance decreases slowly, and at 30–35 per cent by weight it reaches a maximum, beyond which it suddenly decreases sharply and, with increasing concentrations (about 70 per cent by weight), approaches a saturation value almost asymptotically. This trend was proved to be true of the system : natural rubber-CK-IV carbon black. Here it must be noted that the exact course of the curve is of only slight significance, since the values obtained are decisively influenced by the nature and duration of the mixing process, the time and temperature of storage, preliminary treatment, temperature of measuring, field strength, and form and quality of electrode, and especially by the duration of the measurements. The direction of the influence of these variables is quite interesting. Mixing on a roll mill gives in most cases higher specific resistance than does mixing in an internal mixer. If samples are taken after so mixing, but before the product is put on a roll mill, no significant difference in the resistance of individual batches is observed, even if they are mixed at different temperatures.
Spontaneous Contraction of Rubber. II. Spontaneous Contraction of Rubber and Its Dependence on the Conditions of Testing, and Some Factors Concerned in Compounding and Technology
Authors: Reznikovskii˘ M. M. , Khromov M. K. 
Published: February 2011

Abstract
1. An apparatus and method for the study of the spontaneous contraction of rubber are described. 2. Data are offered which were obtained in a study of the dependence of spontaneous contraction of unloaded vulcanizates of isoprene, butadiene, and butadiene-styrene elastomers on the experimental conditions (deformation, temperature, and period of deformation), on the type of compound, and on technological factors (time of vulcanization). 3. It is shown that the theory of spontaneous contraction of rubber developed by the authors is in good accord with the experimental results, and makes it possible to use the method of spontaneous contraction for determining experimentally the basic factors characterizing the elastic and relaxation properties of rubber.
Mechanism of the Action of Accelerators of Vulcanization. Vulcanization of Rubber by a Sulfur Radioisotope
Authors: Blokh G. A. 
Published: February 2011

Abstract
The problem of the mechanism of the action of accelerators and vulcanizing agents during the vulcanization of rubber has been studied in earlier works. It was shown that, during the vulcanization of natural and sodium-butadiene rubber, accelerators of the type of mercaptobenzothiazole and tetramethylthiuram disulfide enter into exchange reactions with the vulcanizing agent, sulfur. However, the role of the chemically combined sulfur, that is, the so-called bridge sulfur, in the exchange reactions with the accelerators remained unexplained. As Dogadkin and Tarasova show, in the case of sulfur vulcanizates, the following kinds of bonds between the rubber chains can occur : (1) —C—C—, formed as a result of polymerization or condensation processes (bond energy 62.7 kcal. per mole); (2) —C—S—C—, monosulfide bonds, formed during thiuram vulcanization (bond energy 54.5 kcal. per mole) ; (3) —C—S—S—C—, disulfide bonds; (4) —C—Sn—C—, polysulfides, formed during vulcanization with elemental sulfur in the absence of accelerators containing sulfur (bond energy 27.5 kcal. per mole). These authors established the presence of polysulfide bonds by extracting sulfur from vulcanizates, already extracted with cold acetone, by heating the extracted vulcanizate in a 10 per cent solution of sodium sulfite. Ten to twenty per cent of the total amount of combined sulfur was thus extracted as polysulfide, whereas rubber vulcanized with thiuram contained no sulfur at all which could be extracted by sodium sulfite. In order to study the exchange reactions between accelerators containing sulfur and chemically combined or bridge sulfur, the present investigation was made.
Successful Strategies for Recruitment of Emergency Medical Volunteers
Authors: Hasselmann Anne Rinchiuso 
Published: February 2011

AbstractObjectivesA robust medical volunteer program is critical to ensuring a successful response to public health and medical emergencies. The New York City (NYC) Department of Health and Mental Hygiene created the NYC Medical Reserve Corps in 2003 to build a multidisciplinary team of health professionals who wish to assist NYC with response during large-scale health emergencies. This article reports on the search to determine which recruitment activities have been most successful to date, with the goal of modeling future activities upon those that worked best.MethodsA retrospective review of effectiveness of recruitment strategies to identify and register new NYC Medical Reserve Corps volunteers was undertaken.ResultsA broad range of recruitment activities have been implemented since the program's inception, with varying degrees of success. Various recruitment modalities were tried, including direct invitations to licensed professionals by the NYC Health Commissioner and announcements through professional organization partners. The direct invitation by the NYC Health Commissioner to health professionals licensed in 1 of the 5 boroughs of NYC has proved to be the most successful recruitment tool to date.ConclusionsThe local health commissioner or other trusted community figure is an excellent messenger for recruiting emergency volunteers. It is also critical that recruitment messages reach as many potential volunteers as possible to ensure that the requisite number of volunteers and mix of professional disciplines are identified. (Disaster Med Public Health Preparedness. 2013;7:266-271)
Phenolic Resins
Authors: Hesse Wolfgang , Lang Jürgen 
Published: February 2011

AbstractThe article contains sections titled:1.Introduction2.Physical Properties3.Raw Materials3.1.Phenols3.2.Aldehydes3.3.Catalysts4.Production4.1.Novolacs4.2.Resols4.3.Phenolic Resins Modified by Natural Resins4.4.Phenolic Resins with Special Properties4.5.Wastewater5.Storage and Transportation6.Testing and Analysis7.Uses7.1.Novolacs7.1.1.Cross‐Linked Novolacs7.1.2.Novolacs without Cross‐Linking7.2.Resols7.2.1.Water‐Soluble Resols7.2.2.Resols in Organic Solvents7.2.3.Alkylphenol Resols7.3.Phenolic Resins Modified by Natural Resins7.4.Waterborne Paints, Phenol Ether Resins7.5.High‐Temperature Coking8.Economic Aspects9.Toxicology and Occupational Health
Tantalum and Tantalum Compounds
Authors: Albrecht Sven , Cymorek Christian , Andersson Klaus , Reichert Karlheinz , Wolf Rüdiger 
Published: February 2011

AbstractThe article contains sections titled:1.Introduction2.Properties2.1.Physical Properties2.2.Chemical Properties3.Occurrence4.Extraction4.1.Extraction and Processing of Ore Concentrates4.2.Obtaining Ta ‐ Nb Concentrates from Tin Slags4.3.Processing Tantalum Scrap5.Metallic Tantalum5.1.Production5.2.Semifinished Products5.3.Tantalum Powder for Capacitors5.4.Other Uses6.Tantalum Alloys7.Tantalum Compounds8.Analysis9.Economic Aspects10.Toxicology
Nondestructive Testing, 3. Ultrasonics
Authors: Ono Kanji , Erhard Anton 
Published: February 2011

AbstractThe article contains sections titled:1.Introduction2.Physical Basis3.Generation and Detection3.1.Conventional Probes3.2.Piezocomposite Materials for Ultrasound Generation3.3.Phased Array Technique3.3.1.Phased Array Probes3.3.2.Applications4.Inspection Methods5.Display Methods6.Interpretation7.Inspection Standards
Mutagenesis Mechanisms
Authors: Polosina Yaroslava Y , Cupples Claire G 
Published: February 2011

Abstract

Deoxyribonucleic acid
(DNA), the keeper of genetic information in all organisms, is constantly modified by internal and external factors during the cell's lifetime. Many types of DNA modification cause mutations. Although mutations may be harmful to individual cells or organisms, mutation in populations is valuable because it leads to genetic variation and ultimately to evolution. There are even circumstances when it is useful to increase the number of mutations in a cell. Maintaining the optimum balance between genetic stability and variability requires the cell to regulate both the frequency with which modifications to the DNA occur, and the efficiency with which the original sequence is restored by the various DNA repair pathways. One group of cellular enzymes, the
DNA polymerases
, plays a key role in both mutation occurrence and mutation avoidance. In this article we consider how mutations occur in DNA, and how cells regulate their mutation rate, with an emphasis on the role of the
DNA polymerases
.

Key Concepts:

Modification of DNA structure is the first step in the pathway to mutation.

Most structural changes in DNA are caused by normal physiological processes.

Mutation frequency depends on the frequency of DNA structural change and the efficiency of DNA repair processes.

DNA polymerase is the key enzyme of mutagenesis.

Mutations are a cause of genetic disease.

Mutations are the raw material for evolution.

To ensure survival, cells must maintain the optimal balance between genetic stability and variability.
Bornaviruses
Authors: Lipkin W Ian , Briese Thomas 
Published: February 2011

Abstract

Borna disease virus

(BDV) is a nonsegmented negative‐strand
ribonucleic acid
(RNA) virus that is unique among viruses of the order
Mononegavirales
in its genomic organisation, nuclear localisation for replication and transcription, splicing and neurotropism. Most reports of natural infection have described outbreaks in horses and sheep in central Europe; however, the virus appears to be distributed worldwide and has the potential to infect many, if not all, warm‐blooded hosts, causing disorders of the central, peripheral and autonomic nervous systems. In horses and sheep BDV is associated with fatal meningoencephalitis. In parrots and related exotic birds the recently characterised avian Bornavirus (ABV) may also infect the central nervous system; however, disease is typically manifest as a wasting disease due to autonomic nervous system infection and impaired peristalsis in the gastrointestinal tract. Whether bornaviruses infect humans remains controversial.

Key Concepts:

Borna disease virus is unique in its molecular biology, broad host range and neurotropism.

As the first infectious agent identified through subtractive cloning Borna disease virus is an example of the power of molecular biology in pathogen discovery.

The controversy over the role of Borna disease virus in human disease illustrates the complexity of proving causation using molecular diagnostics.
Primary Immunodeficiency Affecting the Innate Immune System
Authors: Rosenzweig Sergio D 
Published: February 2011

Abstract

Primary immunodeficiencies are a heterogeneous group of genetically inherited diseases quantitively or functionally affecting innate or adaptive immunity. The innate and adaptive arms of the immune system work synergistically to efficiently control and neutralise the wide range of pathogens that challenge vertebrates. Although at first glance innate immunity might appear primitive, innate immune cells can orchestrate discrete immune responses to different infections through the recognition of diverse pathogens by germline‐encoded pattern recognition receptors. Neutrophils, macrophages, dendritic cells, natural killer (NK) cells and NKT cells, in conjunction with natural antimicrobial agents, opsonins (as Complement) and cytokines, are critical innate components in neutralising infectious agents. Primary immunodeficiencies are understood as a state of primary lack of protective immunity. Different compartments of the innate immune system are analysed in this article to highlight their critical pathophysiological role in host defences and protective immunity.

Key Concepts:

The innate immune system includes epithelial and mucosal barriers, cells, natural antimicrobial product, pattern recognition receptors (PRR) and cytokines to protect the host from infections without the need of previous exposure to those microorganisms.

Neutrophil disorder should be suspected in patients with recurrent, severe, bacterial or fungal infections, especially those caused by unusual organisms.

The mononuclear phagocytes are crucial for antigen presentation and for protection against intracellular infections, especially mycobacteria.

Natural killer cell deficiency could involve quantitative and functional defects, in both cases showing increased susceptibility to viral infections.

Natural killer T (NKT) cells constitute a distinctive subpopulation of mature lymphocytes that coexpress NK (CD56) and T (CD3) cell antigens and play a central role in infectious (e.g. virus), allergic (e.g. asthma) and autoimmune diseases (e.g. hepatitis), as well as tumour control.

The complement system is a cascade system of more than 30 serum and membrane‐bound proteins that, when deficient, leads to impaired host defence and inappropriate inflammation.
Tumour Suppressor Genes
Authors: Skolnik Jeffrey M , Fisher David 
Published: February 2011

Abstract

Tumour suppressor genes are a group of genes whose loss contributes to malignancy. The original hypothesis surrounding tumour suppressor genes defined a ‘two‐hit’ requirement for mutagenesis; however, it is now known that deletion, silencing or downregulation of one or more genes may lead to cancer formation. There is a growing list of putative tumour suppressor genes, and recently several new candidates were added. Research into apoptosis, or programmed cell death, continues to expand. As pathways for which tumour suppressor genes are responsible become clearer, so do potential therapeutics to capitalise on these targets. A summary of the mechanisms by which tumour suppressor genes may act, the mutations which lead to tumourigenesis, and the clinical implications of these phenomena are presented.

Key Concepts:

Tumour suppressor genes prevent mutagenesis.

Perturbation of tumour suppressor gene function may lead to cancer formation.

The first tumour suppressor gene identified was the Rb gene, and mutations in the gene lead to the childhood cancer known as retinoblastoma.

Although many tumour suppressor genes require two mutations to cause a loss‐of‐function, in some cases, downregulation of a single tumour suppressor gene may lead to cancer.

The p53 gene is involved in a complex pathway of cell death and cell arrest, and mutations in p53 or other genes in the pathway can lead to the development of cancer.

There are several other modulators of tumour formation, including telomeres, adhesion molecules and microRNA, that may function like tumour suppressor genes.

Identification of tumour suppressor genes has lead to the development of anticancer therapeutic agents targeted to specific pathways that take advantage of this knowledge.