Effect of Metallic Poisons. Especially Manganese, on Aging of Vulcanized Natural Rubber

1947 ◽  
Vol 20 (3) ◽  
pp. 821-826
Keyword(s):  
Organic Acids ◽  
Natural Rubber ◽  
Harmful Effect ◽  
Manganese Compound ◽  
Naturally Occurring ◽  
Different Types ◽  
Salts Of Organic Acids ◽  
General Experience ◽  
Manganese Compounds ◽  
Harmful Effects

Abstract 1. Information received from rubber manufacturers on their experience of the effects of manganese and copper on aging is summarized. Although there is evidence that the amounts of these impurities in fillers tended to increase during the early war years (1939–42), it seems to be the general experience that little trouble arose from their effects on the properties of the rubber. Fillers containing as much as 0.05–0.10 per cent of manganese, or 0.005 per cent of copper, have not shown any obvious harmful effects. 2. Experiments with a large number of manganese compounds, including naturally occurring (mineral) forms and salts of organic acids, used in amounts equivalent to 0.01 per cent manganese on the raw rubber, have failed to show any pronounced harmful effect on the aging (oven or oxygen bomb) of a vulcanized natural rubber containing mercaptobenzothiazole, although deterioration was noticeably accelerated in some cases. Probably on account of the smallness of the effects observed, it is not possible as yet to draw any conclusion as to the relative activities of different types of manganese compound. 3. According to results of previous workers, manganese in the amount used in the present experiments can produce a more serious effect than these experiments indicate. The effect of manganese is known to depend on the type of mix used, and this aspect of the problem would thus appear to merit further investigation, as does also the influence of the method and degree of dispersion of the manganese compound in the rubber mix.

NMR Assisted Antimicrobial Peptide Designing: Structure Based Modifications and Functional Correlation of a Designed Peptide VG16KRKP

2020 ◽  
Vol 27 (9) ◽  
pp. 1387-1404 ◽  
Author(s):  
Karishma Biswas ◽  
Humaira Ilyas ◽  
Aritreyee Datta ◽  
Anirban Bhunia
Keyword(s):  
Antimicrobial Agents ◽  
Biological Properties ◽  
Structure Characterization ◽  
Drug Resistant ◽  
Functional Correlation ◽  
Naturally Occurring ◽  
High Resolution Nmr ◽  
Different Types ◽  
Reduced Activity ◽  
Poor Stability

Antimicrobial Peptides (AMPs), within their realm incorporate a diverse group of structurally and functionally varied peptides, playing crucial roles in innate immunity. Over the last few decades, the field of AMP has seen a huge upsurge, mainly owing to the generation of the so-called drug resistant ‘superbugs’ as well as limitations associated with the existing antimicrobial agents. Due to their resilient biological properties, AMPs can very well form the sustainable alternative for nextgeneration therapeutic agents. Certain drawbacks associated with existing AMPs are, however, issues of major concern, circumventing which are imperative. These limitations mainly include proteolytic cleavage and hence poor stability inside the biological systems, reduced activity due to inadequate interaction with the microbial membrane, and ineffectiveness because of inappropriate delivery among others. In this context, the application of naturally occurring AMPs as an efficient prototype for generating various synthetic and designed counterparts has evolved as a new avenue in peptide-based therapy. Such designing approaches help to overcome the drawbacks of the parent AMPs while retaining the inherent activity. In this review, we summarize some of the basic NMR structure based approaches and techniques which aid in improving the activity of AMPs, using the example of a 16-residue dengue virus fusion protein derived peptide, VG16KRKP. Using first principle based designing technique and high resolution NMR-based structure characterization we validate different types of modifications of VG16KRKP, highlighting key motifs, which optimize its activity. The approaches and designing techniques presented can support our peers in their drug development work.

scholarly journals Modified Nanoclays/Straw Fillers as Functional Additives of Natural Rubber Biocomposites

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 799
Author(s):  
Justyna Miedzianowska ◽  
Marcin Masłowski ◽  
Przemysław Rybiński ◽  
Krzysztof Strzelec
Keyword(s):  
Natural Rubber ◽  
Raw Materials ◽  
Research Work ◽  
Damping Properties ◽  
Main Research ◽  
Functional Additives ◽  
Different Types ◽  
Elastomeric Materials ◽  
Research Goal ◽  
The Impact

Increasingly, raw materials of natural origin are used as fillers in polymer composites. Such biocomposites have satisfactory properties. To ensure above-average functional properties, modifications of biofillers with other materials are also used. The presented research work aimed to produce and characterize elastomeric materials with a straw-based filler and four different types of montmorillonite. The main research goal was to obtain improved functional parameters of vulcanizates based on natural rubber. A series of composites filled with straw and certain types of modified and unmodified nano-clays in various ratios and amounts were prepared. Then, they were subjected to a series of tests to assess the impact of the hybrids used on the final product. It has been shown that the addition of optimal amounts of biofillers can, inter alia, increase the tensile strength of the composite, improve damping properties, extend the burning time of the material and affect the course of vulcanization or cross-linking density.

scholarly journals Phytotoxicity and Other Adverse Effects on the In Vitro Shoot Cultures Caused by Virus Elimination Treatments: Reasons and Solutions

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 670
Author(s):  
Katalin Magyar-Tábori ◽  
Nóra Mendler-Drienyovszki ◽  
Alexandra Hanász ◽  
László Zsombik ◽  
Judit Dobránszki
Keyword(s):  
Adverse Effects ◽  
Physiological Condition ◽  
Harmful Effect ◽  
Shoot Cultures ◽  
Virus Elimination ◽  
In Vitro Shoots ◽  
Further Development ◽  
In Vitro Shoot Cultures ◽  
Harmful Effects

In general, in vitro virus elimination is based on the culture of isolated meristem, and in addition thermotherapy, chemotherapy, electrotherapy, and cryotherapy can also be applied. During these processes, plantlets suffer several stresses, which can result in low rate of survival, inhibited growth, incomplete development, or abnormal morphology. Even though the in vitro cultures survive the treatment, further development can be inhibited; thus, regeneration capacity of treated in vitro shoots or explants play also an important role in successful virus elimination. Sensitivity of genotypes to treatments is very different, and the rate of destruction largely depends on the physiological condition of plants as well. Exposure time of treatments affects the rate of damage in almost every therapy. Other factors such as temperature, illumination (thermotherapy), type and concentration of applied chemicals (chemo- and cryotherapy), and electric current intensity (electrotherapy) also may have a great impact on the rate of damage. However, there are several ways to decrease the harmful effect of treatments. This review summarizes the harmful effects of virus elimination treatments applied on tissue cultures reported in the literature. The aim of this review is to expound the solutions that can be used to mitigate phytotoxic and other adverse effects in practice.

scholarly journals Effects of negative social information on the willingness to support charities: the moderating role of regulatory focus

2020 ◽  
Author(s):  
Nhat Quang Le ◽  
Magne Supphellen ◽  
Richard P. Bagozzi
Keyword(s):  
Regulatory Focus ◽  
Social Information ◽  
Harmful Effect ◽  
Promotion Focus ◽  
Positive Effects ◽  
Willingness To Donate ◽  
The Social ◽  
Group Members ◽  
Harmful Effects

Abstract Donation campaigns that have an unsuccessful start often trigger negative social information in the social and mass media (e.g., “few others have donated so far”). Little research exists to shed light on the effects of such information in the context of donations. Across three studies involving different causes and different channels of communication, we find harmful effects of negative social information on the willingness to donate among prevention-focused consumers but tendencies of positive effects for consumers with a promotion focus. We identify response efficacy as a mediator of the harmful effect for prevention-focused consumers. This finding suggests that social proof theory is not sufficient to explain the harmful effect of negative social information. Alternative mediators are tested and rejected. The findings imply that an effective strategy to avoid harmful effects of negative social information is to trigger a promotion focus in target group members and communicate facts about charity effectiveness.

Natural rubber latex membranes incorporated with three different types of propolis: Physical-chemistry and antimicrobial behaviours

2019 ◽  
Vol 97 ◽  
pp. 576-582 ◽  
Author(s):  
Daniela Cervelle Zancanela ◽  
Cristiano Soleo Funari ◽  
Rondinelli Donizetti Herculano ◽  
Vinicius Moreira Mello ◽  
Clenilson Martins Rodrigues ◽  
...  
Keyword(s):  
Physical Chemistry ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Different Types

Characterizing the naturally occurring sacrificial bond within natural rubber

Polymer ◽  
2019 ◽  
Vol 161 ◽  
pp. 41-48 ◽  
Author(s):  
Xuan Fu ◽  
Cheng Huang ◽  
Yong Zhu ◽  
Guangsu Huang ◽  
Jinrong Wu
Keyword(s):  
Natural Rubber ◽  
Naturally Occurring

scholarly journals Non-Negligible Effects of UV Irradiation on Transformation and Environmental Risks of Microplastics in the Water Environment

2021 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
Fangyuan Cheng ◽  
Tingting Zhang ◽  
Yue Liu ◽  
Yanan Zhang ◽  
Jiao Qu
Keyword(s):  
Environmental Factors ◽  
Uv Irradiation ◽  
Water Environment ◽  
Oxidative Degradation ◽  
Environmental Risks ◽  
Important Process ◽  
Environmental Behaviors ◽  
Environmental Media ◽  
Different Types ◽  
Harmful Effects

Microplastics (MPs) are ubiquitous in environmental media, and their harmful effects on MPs on the ecosystem have attracted more and more attention. Once released into the environment, MPs can trigger oxidative degradation through ultraviolet (UV) to cause photoaging. Photoaging significantly affects the properties of MPs, which leads to changing their environmental behaviors and increasing environmental risks. In this review, the generation of MPs under UV irradiation and the influence of environmental factors on the photoaging of MPs were discussed. Photoaging of MPs is an important process affecting the migration, transformation and interaction of pollutants in water and soil. In order to fully predict the fate and environmental interaction of MPs, more researches are needed in the future to explore the photoaging behavior of different types of MPs under natural environmental conditions.

The behaviour of additives in explosions and the mechanism of antiknock. I

1960 ◽  
Vol 259 (1298) ◽  
pp. 304-324 ◽  
Keyword(s):  
The Other ◽  
Manganese Compound ◽  
Tin Compounds ◽  
Induction Periods ◽  
Auto Ignition ◽  
Metal Additives ◽  
Manganese Tricarbonyl ◽  
Absorption And Emission Spectroscopy ◽  
Manganese Compounds ◽  
Iron And Manganese

The behaviour of Te Me 2 , I 2 , Si Me 4 , Sn Et 4 , methyl cyclo pentadienyl manganese tricarbonyl ( AK -33X), Fe(CO) 5 , ferrocene, Hg vapour and Hg ( iso -propyl) 2 was observed during explosions of amyl nitrite (sensitizer), n -heptane and oxygen. After flash initiation, the reactions were followed by kinetic absorption and emission spectroscopy. The effect of these substances with respect to antiknock action, smoke formation, effect on induction period (preflame reaction) and the emission of light, has been recorded. With the tin and transition metal additives, smokes formed during the induction periods, characterized by a continuous scattering over the entire continuum. A K -33X increased or decreased the induction periods, according to the conditions. TeMe2 and I 2 increased the induction periods by homogeneous reactions. None of the other compounds changed the duration of the induction periods, including the iron compounds which are known to be antiknocks. With the iron and tin compounds included in the charges, smokes formed early in the induction periods and it was therefore concluded that the colloidal solids formed during the combustion of these compounds do not delay auto-ignition by preflame end gas reactions. It follows that there are two mechanisms of antiknock. It is suggested that the occurrence of heterogeneous inhibition is contrary to experience: (a) because there is insufficient surface exposed, (b) because the efficiency of reaction of chain centres at surfaces is low, (c) because the other antiknocks, Te Me 2 I 2 and Pb Et 4 act homogeneously. It is proposed that the second mechanism of antiknock, into which category the iron and manganese compounds fall, is a result of the reaction of the additive on the burnt or burning gases, rather than on the unburned gases. An intense emission of infra-red and visible light from explosions containing iron and manganese may be related to their mechanism as antiknocks; it is suggested that the increase in radiative cooling, caused by excitation and fluorescence of gaseous metal oxides and/or specific deactivation of propagating centres by metal or metal oxide species, plays an important role in this effect. The manganese compound also exhibits antiknock properties of the first type.

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