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Extraction and Chemistry of Rubber Allergens
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Personal protective gloves are made of natural rubber latex (NRL) or a variety of synthetic rubbers, including styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), ethylene propylene diene monomer rubber (EPDM), and polychloroprene rubber (neoprene, CR). NRL can be obtained from several different plants, but the major commercial source is the Pará rubber tree (Hevea brasiliensis). These trees are tapped to obtain the latex (isoprene) containing exudate. Notable alternate sources of NRL include the Guayule shrub (Parthenium argentatum), goldenrod, and the Russian dandelion (Taraxacum koksaghyz), as the latex products produced from these plant extracts have similar properties to that from the Pará rubber tree.1Hevea brasiliensis proteins, when contacted or inhaled are known to cause allergy and anaphylaxis. Guayule rubber is considered hypoallergenic as it doesn't contain the same proteins noted in Hevea brasiliensis that elicit severe allergic reactions.2
Abrasive Flow Finishing
Published in S Santhosh Kumar, Somashekhar S. Hiremath, Role of Surface Modification on Bacterial Adhesion of Bio-Implant Materials, 2020
S Santhosh Kumar, Somashekhar S. Hiremath
Kar et al. (2009a) developed and studied the performance of five different types of polymers-based abrasive media: (a) natural rubber, (b) ethylene propylene diene monomer, (c) butyl rubber, (d) silicone rubber, and (e) styrene butadiene rubber mixed with SiC abrasive particles. Out of five media styrene butadiene, rubber-based media shows better performance in terms of viscosity, thermal stability, and finishing of work surfaces. They have conducted a study on commercial media and found a composition of 66% abrasives, 34% carrier, and other ingredients in the commercial media using thermogravimetric analysis. Kar et al. (2009b) used two different rubbers for media development – (a) natural rubber + SiC abrasive particles and (b) butyl rubber + SiC abrasive particles with naphthenic oil as processing oil. The rheological properties of the media and the effect of these media on the finishing process were studied. Based on the experiments conducted, Butyl rubber-based abrasive media had shown good performance compared to natural rubber-based media. Sankar et al. (2011) developed styrene-butadiene-based media to finish the aluminium-based metal matrix composites. They have also investigated the effect of rheological properties of abrasive media on the finishing and the obtained results are explained with respect to the media properties.
Multicentre Studies
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Terez Sera, Ronald Boellaard, Andres Kaalep, Michael Ljungberg
Twenty-two cameras on 15 sites from 10 countries and 8 different manufacturers were evaluated for inclusion in the ENCDAT study. All scanners matched the required level of specification, so they could be connected into a network. To prepare the network for the DaTSCAN studies of the normal controls, 123I SPECT images of an anthropomorphic striatal phantom (Figure 27.1b) were acquired. In order to avoid the interoperator variability the measurements were performed by one appointed physicist. The phantom was filled with nominal ratios of 10:1, 8:1, 5:1, 4:1, 2.5:1, 2:1 and 1:1. The absolute ratios were measured from aliquots using well counters at the participating centres. All phantom images were acquired over 360 degrees, mostly with pixel sizes between 2–3 mm. Besides the photopeak energy window (159±10%), projections were also acquired in the lower (138±3.5%) and upper (184±3%) scatter windows to evaluate the importance of scatter and septal penetration correction (SSPC) with the triple energy window method. All images were sent to the ENCDAT study core lab for the reconstruction and analysis. OSEM (10/10 or 12/8 iterations/subsets for sets of 120 and 128 projections respectively) was performed with attenuation correction only and additional SSPC. For the quantification, the specific binding ratio (SBR) [36, 37] was measured. The aliquots provided the benchmark against which the SBR measurements were assessed. Linear regression was applied to derive calibration curves, whose slope gave the recovery coefficient (RC) for each camera.
Early Buckle Migration and Restrictive Strabismus after Successful Medical Management of Scleral Buckle Infection
Published in Journal of Binocular Vision and Ocular Motility, 2019
V G Madanagopalan, Fredrick Mouttapa, Jivitesh Singh
The most common indications for SBR are SB exposure or infection.2,3 The overall rate of SBR ranges from 5.7–12%.8,9 SB infection has also been implicated in buckle extrusion.6 Immediate surgical intervention and removal of the explant is usually recommended as SB infection has the propensity to quickly escalate to endophthalmitis or panophthalmitis.3 A variety of pathogens have been implicated in SB infection.10,11 Among the gram positive cocci, MRSA is notorious for being resistant to a wide range of β–lactam antibiotics. A search of the literature did not show any reports of successful treatment of SB infection without buckle removal. In our patient, the isolate was susceptible to cephalosporins and therefore, we tried a conservative approach avoiding immediate SB removal. Administration of systemic and topical antibiotics was sufficient to control the infection. Clinical improvement was noted as early as day 2 and complete resolution was noted in a month.
Exposure to 1,3-Butadiene in the U.S. Population: National Health and Nutrition Examination Survey 2011–2016
Published in Biomarkers, 2021
Alma Nieto, Luyu Zhang, Deepak Bhandari, Wanzhe Zhu, Benjamin C. Blount, Víctor R. De Jesús
1,3-Butadiene is a volatile organic compound (VOC) with a gasoline-like odour that is primarily used as a monomer in the production of synthetic rubber (ATSDR 2012, OSHA 2012). This compound is also used in the polymer production of styrene-butadiene rubber and acrylonitrile-butadiene-styrene resin plastics (EPA 2002, ATSDR 2012). Environmental sources of 1,3-butadiene include industrial emissions; automobile exhaust; burning of wood, plastics, and rubber; cigarette smoke (ATSDR 2012); and cooking emissions (Huang et al. 2020). Additionally, 1,3-butadiene has been found in plastic containers and selected foods (Yurawecz et al. 1976, McNeal and Breder 1987, Abrantes et al. 2000). Inhalation is the main route of exposure. Exposure by ingestion is unlikely since 1,3-butadiene rapidly evaporates to the atmosphere. 1,3-Butadiene is poorly soluble in water; however, low levels are released to water and soil (EPA 2002, ATSDR 2012). In the United States, the reference concentration for breathing 1,3-butadiene in air is 0.9 ppb (EPA 2002); the legal occupational exposure limit is set to 1 ppm for an 8-h workday and a short-term exposure limit of 5 ppm for 5 minutes (OSHA 1996). Ambient 1,3-butadiene undergoes photo-initiated chemical breakdown and is expected to have a half-life of approximately 6 h (ATSDR 2012), or 2–10 h as estimated from inhalation studies in animals (Bond et al. 1987). Nonetheless, low levels of 1,3-butadiene are constantly present in urban and suburban areas due to automobile exhaust, biomass burning, or industrial emissions (Hendler et al. 2010, ATSDR 2012, Gallego et al. 2018, Xiong et al. 2020).
Suberosin Alleviates Sepsis-Induced Lung Injury in A Rat Model of Cecal Ligation and Puncture
Published in Journal of Investigative Surgery, 2023
Sevgi Karabulut Uzunçakmak, Zekai Halıcı, Songül Karakaya, Zerrin Kutlu, Yavuz Selim Sağlam, İsmail Bolat, Pelin Aydın, Ceyda Sibel Kılıç
In conclusion, this is the first study to show the protective effects of SBR isolated from F. cassia in the lungs of septic rats. SBR alleviated sepsis-induced lung injury. This compound may be considered as an alternative therapy for conditions such as impaired oxidative balance and excessive cytokine production in cases of sepsis. Further investigations of SBR with different methods in different diseases will contribute to a better understanding of the effects of this compound.