Permeability of different types of medical protective gloves to acrylic monomers.

PubMed

Lönnroth, Emma-Christin; Wellendorf, Hanne; Ruyter, Eystein

2003-10-01

Dental personnel and orthopedic surgeons are at risk when manually handling products containing methyl methacrylate (MMA). Dental products may also contain cross-linking agents such as ethylene glycol dimethacrylate (EGDMA) or 1,4-butanediol dimethacrylate (1,4-BDMA). Skin contact with monomers can cause hand eczema, and the protection given by gloves manufactured from different types of material is not well known. The aim of this study was to determine the breakthrough time (BTT, min) as a measure of protection (according to the EU standard EN-374-3) for a mixture consisting of MMA, EGDMA and 1,4-BDMA. Fifteen different gloves representing natural rubber latex material, synthetic rubber material (e.g. nitrile rubbers), and synthetic polymer material were tested. The smallest monomer MMA permeated within 3 min through all glove materials. A polyethylene examination glove provided the longest protection period to EGDMA and 1, 4-BDMA (> 120 min and 25.0 min), followed by the surgical glove Tactylon (6.0 min and 8.7 min) and the nitrile glove Nitra Touch (5.0 min and 8.7 min). This study showed that the breakthrough time (based on permeation rate) cannot be regarded as a 'safe limit'. When the permeation rate is low, monomers may have permeated before BTT can be determined. Using double gloves with a synthetic rubber inner glove and a natural rubber outer glove provided longer protection when the inner glove was rinsed in water before placing the outer glove on top.

The use of powdered gloves in dental practice: a cause for concern?

PubMed

Field, E A

1997-01-01

To critically review the potential hazards associated with the use of powdered, natural rubber latex (NRL) gloves in dental practice and to report some practical difficulties which may be encountered when handling dental materials with powdered NRL gloves. Articles published in the international literature over the last 10 years. A number of recent studies in the medical and surgical literature have confirmed that NRL proteins leach out of latex gloves and bind to surgical glove powders. The most serious, potential hazard associated with the continued use of powdered NRL gloves in dental practice is that of latex sensitization by exposure to aerosolized NRL proteins. Hand dermatitis is now recognized as an occupational hazard in dentistry and has been associated with the continuous wearing of protective gloves. Studies, in the dermatological literature, have suggested that glove powders may exacerbate an irritant dermatitis and enhance the potential for adverse reactions to other components of NRL gloves. The surgical literature has already highlighted the risks of post-operative granuloma formation, due to glove powder contamination of the surgical wound. The possible effects of powder contamination of dental implant sites, on the outcome and success of implants has yet to be established. Recent in vitro studies have investigated the effect of latex glove contamination on the shear-bond strength of porcelain laminate veneers: one study demonstrated that starch powder significantly affected the bond strength, whereas the other showed that latex glove contamination of the porcelain surface did not have any significant effect. Long-term, in vivo studies are now required. Dental practitioners should consider the potential health risks which are associated with the use of powdered NRL in dental practice. Powder contamination may affect the long-term results and success of clinical procedures in dentistry.

Development of an Economical Method to Reduce the Extractable Latex Protein Levels in Finished Dipped Rubber Products

PubMed Central

Perera, Ambegoda Liyanage Harini Amalka

2017-01-01

Natural rubber latex (NRL) allergy is caused by the extractable latex proteins in dipped rubber products. It is a major concern for the consumers who are sensitive to the allergenic extractable proteins (EP) in products such as NRL gloves. Objective of this research was to develop an economical method to reduce the EP in finished dipped NRL products. In order to reduce the EP levels, two natural proteases, bromelain from pineapple and papain from papaya, were extracted and partially purified using (NH4)2SO4. According to the newly developed method, different glove samples were treated with a 5% solution of each partially purified enzyme, for 2 hours at 60°C. Residual amounts of in treated samples were quantified using the modified Lowry assay (ASTM D5712-10). Bromelain displayed a 54 (±11)% reduction of the EP from the dipped rubber products, whereas it was 58 (±8)% with papain. These results clearly indicate that the selected natural proteases, bromelain, and papain contribute significantly towards the reduction of the total EP in finished NRL products. Application of bromelain enzyme for the aforementioned purpose has not been reported up to date, whereas papain has been used to treat raw NRL towards reducing the EP. PMID:28706952

[Research into sensitization and allergies to latex: results after 10 years of the use of powder-free latex gloves].

PubMed

de Groot, Hans; Patiwael, Jiska A; de Jong, Nicolette W; Burdorf, Alex; van Wijk, Roy Gerth

2013-01-01

To compare the prevalence of sensitization and allergy to natural rubber latex amongst Erasmus Medical Centre (MC) operating theatre employees before and 10 years after the introduction of powder-free latex gloves. Descriptive study. Employees working permanently in the operating theatre were evaluated in 1998 (n = 163) and in 2009 (n = 178) for sensitization and allergies to natural latex by means of questionnaires, serological analyses and skin testing. The prevalence of sensitization and allergies within these 2 groups was then established and compared. The two groups were comparable in terms of gender, smoking habits, job classification, work-related symptoms and the number of individuals who had atopy. In 2009, the prevalence of sensitization to latex was statistically significantly lower than in 1998 (4.5 vs. 14.1%). Allergy to latex was also established a statistically significantly fewer number of times in 2009 than in 1998 (2.8 vs. 9.8%). This same trend could be observed in the subgroup that participated both years (n = 49). Individuals with an atopic constitution had a statistically significant higher risk of developing hypersensitivity to natural latex; the risk of developing an allergy to latex was also higher, but not significantly. After the study in 1998, the introduction of sterile, powder-free latex gloves very likely led to a decline in the prevalence of sensitization and allergy to natural latex in 2009.

Biologically Active Zone Enhancement (BAZE) for In Situ RDX Degradation in Ground Water

DTIC Science & Technology

2010-01-01

geotechnical laboratory testing, will be performed in Level D protection with the addition of chemical resistant gloves. The level of protection for...splash hazards), • Chemical- resistant boots (PVC, Neoprene, Rubber) or work boots with covers ( steel-toed as appropriate), • Inner gloves (latex or...vinyl), • Outer, chemical- resistant gloves (nitrile, PVC, Neoprene), • Safety glasses or goggles, • Hard hat (as required by OSHA), and • Splash

[Incidence and increase in type I allergies to rubber gloves in dental medicine students].

PubMed

Heese, A; Peters, K P; Stahl, J; Koch, H U; Hornstein, O P

1995-01-01

The prevalence of type I allergy against latex was investigated in dental students by questionnaire, prick tests and the determination of specific IgE antibodies. Positive prick tests against different latex fluids were found in 18 (8.7%) of 206 students, with clinical relevance in 11 cases. When the total number of students in each semester was taken into account an increase in the minimal prevalence of clinically relevant latex allergy from 2% in the second semester to 10.4% in the tenth semester was seen. A history of glove intolerance presenting as a wheal-and-flare reaction was associated with a type I allergy against latex in only 50% of the affected subjects. Atopic diseases and hand eczema of different causes proved to be risk factors in 16 and 5 of 18 students with latex allergy, respectively. A high-ammonia accelerator-free latex fluid proved to be a very reliable test medium compared to the less sensitive determination of specific IgE antibodies to latex.

Effect of magnetic and thermal properties of iron oxide nanoparticles (IONs) in nitrile butadiene rubber (NBR) latex

NASA Astrophysics Data System (ADS)

Ong, Hun Tiar; Julkapli, Nurhidayatullaili Muhd; Hamid, Sharifah Bee Abd; Boondamnoen, O.; Tai, Mun Foong

2015-12-01

Nitrile butadiene rubber (NBR) gloves are one of the most important personal protective equipments but they are possible to tear off and contaminate food or pharmaceutical and healthcare products during manufacturing and packaging process. High tendency of torn glove remaining in food or products due to white or light flesh-coloured glove is not easy to be detected by naked eyes. In this paper, iron oxide nanoparticles (IONs) selected as additive for NBR to improve its detectability by mean of magnetic properties. IONs synthesized via precipitation method and compounded with NBR latex before casting on petri dish. The properties of IONs were investigated by X-ray Diffractometry (XRD), Transmission Electron Microscope (TEM), Raman Spectroscopy and Vibrating Sample Magnetometer (VSM). Meanwhile NBR/IONs composites were studied by Thermogravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC) and Vibrating Sample Magnetometer (VSM). It observed that, synthesized IONs shows of 25.28 nm crystallite with 25.86 nm semipherical (changed as) shape. Meanwhile, Magnetite and maghemite phase are found in range of 670 cm-1 and 700 cm-1 respectively, which it contributes magnetization saturation of 73.96 emu/g at 10,000 G by VSM. Thermal stability and magnetic properties were increased with incorporating IONs into NBR latex up to 20 phr. NBR/IONs 5 phr has the optimum thermal stability, lowest glass transition temperature (-14.83 °C) and acceptable range of magnetization saturation (3.83 emu/g at 10,000 G) to form NBR gloves with magnetic detectability.

Natural rubber latex allergy and asthma.

PubMed

Tarlo, S M

2001-01-01

Allergic responses to natural rubber latex (NRL) continue to be reported. In adults, the major exposure is in the occupational setting, especially in relation to NRL glove use by health care workers. Issues addressed over the past year include improving diagnostic methods for NRL allergy and characterization of NRL allergens relevant to various exposure groups and evaluating strategies for prevention and early detection of NRL allergy. Assessment of in vitro tests show good intertest correlation but lower sensitivity compared with skin test responses. NRL allergens have been further characterized as reported in the past year. Development of recombinant Hev b 3, a major NRL allergen relevant to children with spina bifida, enhances the likelihood for improved diagnostic reagents. Preliminary reports of primary preventive strategies suggest that avoidance of high-protein, powdered gloves in health care facilities can be cost-effective and is associated with a decline in sensitized workers.

Outcomes of a natural rubber latex control program in an Ontario teaching hospital.

PubMed

Tarlo, S M; Easty, A; Eubanks, K; Parsons, C R; Min, F; Juvet, S; Liss, G M

2001-10-01

Allergy to natural rubber latex (NRL) has been frequently reported in health care workers. However, there is little published evidence of the outcome of hospital intervention programs to reduce exposure and detect cases of sensitization early. This study assesses the effects of intervention to reduce NRL allergy in an Ontario teaching hospital with approximately 8000 employees. A retrospective review assessed annual numbers of employees visiting the occupational health clinic, allergy clinic, or both for manifestations of NRL allergy compared with the timing of introduction of intervention strategies, such as worker education, voluntary medical surveillance, and hospital conversion to low-protein, powder-free NRL gloves. The number of workers identified with NRL allergy rose annually, from 1 in 1988 to 6 in 1993. When worker education and voluntary medical surveillance were introduced in 1994, a further 25 workers were identified. Nonsterile gloves were changed to low-protein, powder-free NRL gloves in 1995: Diagnoses fell to 8 workers that year, and 2 of the 3 nurses who had been off work because of asthma-anaphylaxis were able to return to work with personal avoidance of NRL products. With a change to lower protein, powder-free NRL sterile gloves in 1997, allergy diagnoses fell to 3, and only 1 new case was identified subsequently up to May 1999. No increased glove costs were incurred as a result of consolidated glove purchases. This program to reduce NRL allergy in employees was effectively achieved without additional glove costs while reducing expenses from time off work and workers' compensation claims.

Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

NASA Astrophysics Data System (ADS)

Keong, C. C.; Zin, W. M. Wan; Ibrahim, P.; Ibrahim, S.

2010-05-01

Radiation prevulcanized natural rubber latex (RVNRL) was claimed to be more user friendly than natural rubber latex prevulcanized by sulphur curing system. The absence of Type IV allergy inducing chemicals in RVNRL make it a suitable material for manufacturing of many kinds of latex products, especially those come into direct contact with users. This paper reveals and discusses the findings of cytotoxicity test and safety evaluation on animal for RVNRL. The test was done on RVNRL films prepared by coagulant dipping method and RVNRL dipped products produced by latex dipped product manufacturers. Cytotocixity test was carried out on mammalian cell culture American Type Culture Collection CCL 81, Vero. Results indicated that no cytotoxic effect from RVNRL films and products was found on the cell culture. Two animal studies, namely dermal sensitization study and primary skin irritation study, were done on gloves made from RVNRL. Albino white guinea pigs were used as test subjects in dermal sensitization study and results showed no sensitization induced by the application of test material in the guinea pigs. Primary skin irritation study was done on New Zealand white rabbits and results showed that the product tested was not corrosive and was not a primary irritant

Double gloving to reduce surgical cross-infection.

PubMed

Tanner, J; Parkinson, H

2002-01-01

The invasive nature of surgery, with its increased exposure to blood, means that during surgery there is a high risk of transfer of pathogens. Pathogens can be transferred through contact between surgical patients and the surgical team, resulting in post-operative or blood borne infections in patients or blood borne infections in the surgical team. Both patients and the surgical team need to be protected from this risk. This risk can be reduced by implementing protective barriers such as wearing surgical gloves. Wearing two pairs of surgical gloves, as opposed to one pair, is considered to provide an additional barrier and further reduce the risk of contamination. The primary objective of this review was to determine if double gloving (wearing two pairs of gloves), rather than single gloving, reduces the number of post-operative or blood borne infections in surgical patients or blood borne infections in the surgical team. The secondary objective of this review was to determine if double gloving, rather than single gloving, reduces the number of perforations to the innermost pair of surgical gloves. The innermost gloves (next to skin) compared with the outermost gloves are considered to be the last barrier between the patient and the surgical team. The reviewers searched the Cochrane Wounds Group Specialised Trials Register, MEDLINE, CINAHL, EMBASE and the Cochrane Controlled Trials Register. Glove manufacturing companies and professional organisations were also contacted. Randomised controlled trials involving: single gloving, double gloving, glove liners or coloured puncture indicator systems. Both reviewers independently assessed the relevance and quality of each trial. Trials to be included were cross checked and authenticated by both reviewers. Data was extracted by one reviewer and cross checked for accuracy by the second reviewer. Two trials were found which addressed the primary outcome. A total of 18 randomised controlled trials which measured glove perforations were identified and included in the review. DOUBLE GLOVING (wearing two pairs of latex gloves). Nine trials compared single latex gloves versus double latex gloves. These found no difference in the number of perforations between the single latex gloves and the outermost pair of the double latex gloves, but the number of perforations to the double latex-innermost glove was significantly reduced when two pairs of latex gloves were worn. ORTHOPAEDIC GLOVES (thicker than standard latex gloves). One trial compared single latex orthopaedic gloves with double latex gloves. This showed there was no difference in the number of perforations to the innermost gloves when wearing double latex gloves compared with a single pair of latex orthopaedic gloves. INDICATOR GLOVES (coloured latex gloves worn underneath latex gloves). Three trials compared double latex gloves versus double latex indicator gloves. These trials showed similar numbers of perforations to both the innermost and the outermost gloves for both gloving groups. Perforations to the outermost gloves were detected more easily when double latex indicator gloves were worn. Wearing double latex indicator gloves did not increase the detection of perforations to the innermost gloves. GLOVE LINERS (an insert worn between two pairs of latex gloves). Two trials compared double latex gloves versus double latex gloves with liners. These trials showed a significant reduction in the number of perforations to the innermost glove when a glove liner was worn between two pairs of latex gloves. CLOTH GLOVES (cloth gloves worn on top of latex gloves). Two trials compared double latex gloves versus latex inner with cloth outer gloves. These trials showed that wearing a cloth outer glove significantly reduced the number of perforations to the innermost latex glove. STEEL WEAVE GLOVES (steel weave gloves worn on top of latex gloves). One trial compared double latex gloves versus latex inner with steel weave outer gloves. This trial showed no reduction in the number of perforations to the innermost glove when wearing a steel weave outer glove. Wearing two pairs of latex gloves significantly reduces the number of perforations to the innermost glove. This evidence comes from trials undertaken in 'low risk' surgical specialties, that is specialties which did not include orthopaedic joint surgery. Wearing two pairs of latex gloves does not cause the glove wearer to sustain more perforations to their outermost glove. Wearing double latex indicator gloves enables the glove wearer to detect perforations to the outermost glove more easily than when wearing double latex gloves. However wearing a double latex indicator system will not assist with the detection of perforations to the innermost glove, nor reduce the number of perforations to either the outermost or the innermost glove. Wearing a glove liner between two pairs of latex gloves to undertake joint replacement surgery significantly reduces the number of perforations to the innermost glove compared with double latex gloves only. Wearing cloth outer gloves to undertake joint replacement surgery significantly reduces the number of perforations to the innermost glove compared with wearing double latex gloves. Wearing steel weave outer gloves to undertake joint replacement surgery does not reduce the number of perforations to innermost gloves compared with double latex gloves.

The Use of Semitranslucent Rubber Pledgets During Microsurgical Dissection of Cerebellopontine Angle Tumors: Technical Note.

PubMed

Mazur, Marcus D; Gurgel, Richard; MacDonald, Joel D

2018-01-01

Dissection of cerebellopontine angle (CPA) tumors that abut or adhere to the brainstem or cranial nerves can be a challenging surgical endeavor. We describe the use of semitranslucent latex rubber pledgets in the tumor-brain interface as a method to improve visualization and protection of vital tissue during microsurgical dissection of CPA masses. The rubber pledgets are fashioned by cutting circular discs out of the cuff portion of talc-free, partially opaque latex gloves. These pledgets provide a semitranslucent, nonadherent membrane that can be placed between vital neural tissues and a tumor capsule to minimize trauma during dissection. The semitranslucent latex enables visualization of the underlying anatomical structures while also providing a protective surface onto which a suction device can be rested to facilitate clearance of the surgical field. A 56-yr-old woman with left ear tinnitus presented with a 3-cm CPA meningioma. During microsurgical dissection, rubber pledgets were used to preserve the interface between the brain stem, cranial nerves, and tumor capsule. The use of the rubber pledgets appeared to secure the interface between to tumor and the brain while at the same time protecting the cranial nerves, brainstem, and cerebellum. Semitranslucent rubber pledgets may facilitate microsurgical dissection of CPA tumors. Copyright © 2017 by the Congress of Neurological Surgeons

Occupational allergic contact dermatitis caused by sterile non-latex protective gloves: clinical investigation and chemical analyses.

PubMed

Pontén, Ann; Hamnerius, Nils; Bruze, Magnus; Hansson, Christer; Persson, Christina; Svedman, Cecilia; Thörneby Andersson, Kirsten; Bergendorff, Ola

2013-02-01

An increased frequency of occupational contact hand dermatitis among surgical operating theatre personnel has been noticed. To evaluate patients with occupational contact dermatitis caused by their rubber gloves, and to describe a method for analysing the content of the allergens in the gloves. Patch tests were performed with the baseline series, a rubber chemical series, and the patients' own gloves. A method for analysing 1,3-diphenylguanidine (DPG) and cetylpyridinium chloride in the gloves was developed. Contact allergy to thiuram mix was found in 8 of 16 patients, whereas 12 of 16 patients reacted to DPG. In 7 of 8 patients, contact allergy to cetylpyridinium chloride was found. In the patients' gloves, cetylpyridinium chloride and DPG were detected at higher concentrations on the inside of the gloves than on the outside. Most patients had worked for decades in their present occupations, but their hand dermatitis had only been present for months. Contact allergy to DPG in gloves has been disputed, but, in this study, we were able to confirm the presence of DPG and cetylpyridinium chloride in the causative gloves by using a modified method for the analysis. The presence of these chemicals in gloves caused an increase in occupational contact dermatitis in surgical operating theatre personnel. © 2012 John Wiley & Sons A/S.

Atypical pattern of (meth)acrylate allergic contact dermatitis in dental professionals.

PubMed

Prasad Hunasehally, R Y; Hughes, T M; Stone, N M

2012-09-01

(Meth)acrylates in dental bonding agents are a common source of allergic contact dermatitis in dental professionals. The distribution of the contact dermatitis is commonly on finger tips, but is determined by individual habits as demonstrated by the two case reports in this article. Despite the site of contact dermatitis, the bonding agents are often not suspected as a source of contact allergy due to misconception regarding the protective effect of natural rubber latex gloves. With these case reports, we endeavour to emphasize the inadequacy of the latex gloves in protecting against the (meth)acrylate induced contact allergy and also list the measures a dental professional needs to incorporate in order to minimise the risks of sensitisation to (meth)acrylates.

The power of glove: Soft microbial fuel cell for low-power electronics

NASA Astrophysics Data System (ADS)

Winfield, Jonathan; Chambers, Lily D.; Stinchcombe, Andrew; Rossiter, Jonathan; Ieropoulos, Ioannis

2014-03-01

A novel, soft microbial fuel cell (MFC) has been constructed using the finger-piece of a standard laboratory natural rubber latex glove. The natural rubber serves as structural and proton exchange material whilst untreated carbon veil is used for the anode. A soft, conductive, synthetic latex cathode is developed that coats the outside of the glove. This inexpensive, lightweight reactor can without any external power supply, start up and energise a power management system (PMS), which steps-up the MFC output (0.06-0.17 V) to practical levels for operating electronic devices (>3 V). The MFC is able to operate for up to 4 days on just 2 mL of feedstock (synthetic tryptone yeast extract) without any cathode hydration. The MFC responds immediately to changes in fuel-type when the introduction of urine accelerates the cycling times (35 vs. 50 min for charge/discharge) of the MFC and PMS. Following starvation periods of up to 60 h at 0 mV the MFC is able to cold start the PMS simply with the addition of 2 mL fresh feedstock. These findings demonstrate that cheap MFCs can be developed as sole power sources and in conjunction with advancements in ultra-low power electronics, can practically operate small electrical devices.

Primary prevention of natural rubber latex allergy in the German health care system through education and intervention.

PubMed

Allmers, Henning; Schmengler, Jörg; Skudlik, Christoph

2002-08-01

The development of occupational asthma and allergic skin reactions caused by natural rubber latex (NRL) allergy are risks for health care workers. There are few published studies to suggest that intervention programs to reduce exposure will lead to primary prevention of sensitization. This study assesses the effects of intervention to reduce the incidence of NRL allergy in personnel working in health care facilities insured by the German statutory accident insurance company for health care workers, Berufsgenossenschaft für Gesundheitsdienst und Wohlfahrtspflege, with approximately 3 million insured employees, by switching to powder-free NRL gloves. The timing of introduction of intervention strategies, such as education of both physicians and administrators, together with regulations demanding that health care facilities only purchase low-protein, powder-free NRL gloves are reported. We reviewed the annual numbers of reported suspected cases of NRL-caused occupational allergies and the amount and type of gloves used in German acute-care hospitals since 1986. The purchase of powder-free NRL examination gloves exceeded that of powdered gloves for the first time in 1998. This only became true for powder-free NRL sterile gloves 2 years later in 2000. The incidence of suspected occupational NRL allergy cases rose until 1998 and has declined steadily since. There was a 2-year lag between the beginning of the decline in the purchase of powdered NRL examination gloves and the beginning of a decline in suspected NRL-caused occupational asthma cases. Despite the effect of increased recognition of NRL allergies, education about NRL allergies in health care facilities combined with the introduction of powder-free gloves with reduced protein levels has been associated with a decline in the number of suspected cases of occupational allergies caused by NRL in Germany on a nationwide scale. These results clearly indicate that primary prevention of occupational NRL allergies can be achieved if these straightforward and practical interventions are properly carried out and maintained.

Medical devices manufactured from latex: European regulatory initiatives.

PubMed

De Jong, W H; Geertsma, R E; Tinkler, J J B

2002-05-01

In Europe the marketing of medical devices manufactured from latex is regulated by directives describing the essential (safety) requirements that products have to fulfill to obtain marketing approval. This paper describes the general requirements for marketing medical devices in Europe and, more specifically, the requirements for products manufactured from natural rubber latex. The requirements for marketing medical devices can be fulfilled by using the relevant harmonized European standards. These standards are regularly under revision to incorporate the latest scientific developments. For certain devices, for example, latex medical (examination and surgical) gloves, specific standards have been published. Medical devices manufactured from latex pose a serious problem because of the risk of induction of allergy both against the latex proteins inherently present (type I or immediate type allergy) and against chemicals added during processing (type IV or delayed type hypersensitivity) present as residues in the latex products. So, besides requirements for product quality in terms of barrier properties, strength, and sterility, the main focus consists of the allergy-inducing properties of the latex products. Recent developments have reopened the discussion on the value of total protein versus allergen determination in latex medical gloves. However, as long as minimal levels needed for both sensitization and elicitation have not been established, a safe maximum level for leachable proteins/allergens in latex products cannot be determined. A European Commission guidance document on the latex allergy problem is currently being drafted by experts from Competent Authorities. Copyright 2002 Elsevier Science (USA).

Analysis of sulfidic linkages formed in natural rubber latex medical gloves by using X-ray absorption near edge structure

NASA Astrophysics Data System (ADS)

Chankrachang, M.; Limphirat, W.; Yongyingsakthavorn, P.; Nontakaew, U.; Tohsan, A.

2017-09-01

A study of sulfidic linkages formed in natural rubber (NR) latex medical gloves by using X-ray Absorption Near Edge Structure (XANES) is presented in this paper. The NR latex compound was prepared by using prevulcanization method, that is, it was prevulcanized at room temperature for 24 hrs before utilization. After the 24 hrs of prevulcanization, the latex film samples were obtained by dipping process. The dipped films were subjected to vulcanize at 110°C for 5 to 25 min. It was observed that after the compound was prevulcanized for 24 hrs, polysulfidic linkages were mainly formed in the sample. It was however found that after curing at 110°C for 5-25 min, the polysulfidic linkages are tended to change into disulfide linkages. Especially, in the case of 25 minutes cured sample, disulfide linkages are found to be the main linkages. In term of tensile strength, it was observed that when cure time increased from 5 - 10 min, tensile strengths were also increased. But when the cure time of the film is 25 minutes, tensile strength was slightly dropped. The dropped of tensile strength when cure time is longer than 10 minutes can be ascribed to a degradation of polysulfidic and disulfidic linkages during curing. Therefore, by using XANES analysis, it was found to be very useful to understand the cure characteristic, thus it can be very helpful to optimize cure time and tensile properties of the product.

Estimation of shelf life of natural rubber latex exam-gloves based on creep behavior.

PubMed

Das, Srilekha Sarkar; Schroeder, Leroy W

2008-05-01

Samples of full-length glove-fingers cut from chlorinated and nonchlorinated latex medical examination gloves were aged for various times at several fixed temperatures and 25% relative humidity. Creep testing was performed using an applied stress of 50 kPa on rectangular specimens (10 mm x 8 mm) of aged and unaged glove fingers as an assessment of glove loosening during usage. Variations in creep curves obtained were compared to determine the threshold aging time when the amount of creep became larger than the initial value. These times were then used in various models to estimate shelf lives at lower temperatures. Several different methods of extrapolation were used for shelf-life estimation and comparison. Neither Q-factor nor Arrhenius activation energies, as calculated from 10 degrees C interval shift factors, were constant over the temperature range; in fact, both decreased at lower temperatures. Values of Q-factor and activation energies predicted up to 5 years of shelf life. Predictions are more sensitive to values of activation energy as the storage temperature departs from the experimental aging data. Averaging techniques for prediction of average activation energy predicted the longest shelf life as the curvature is reduced. Copyright 2007 Wiley Periodicals, Inc.

Troubleshooting for the observed problems in processing latex concentrate from natural resource

NASA Astrophysics Data System (ADS)

Afreen, S.; Haque, K. R.; Huda, M. K.

2013-06-01

Natural latex has special importance in the rubber industry for manufacturing different types of goods like gloves, balloons, male contraceptive and similar thin walled articles. This natural latex is much more sensitive a liquid to handle since it can easily become contaminated and thereby coagulated which makes it unfavourable for centrifuge and getting concentrate from it. Some other related measures also are included in consideration during the processing of concentrate latex from the natural raw latex. The problems that are being faced in a concentrate latex processing plant can be categorized in different groups like, problems related to the latex property, mechanical problems, electrical problems, handling and storage problems, transformation problems, problems related to environmental issues, etc. Among them, the most common and vital problems frequently observed in a concentrate latex processing plant are discussed here with a view to finding the measures for solution which will help to maintain the latex property in any latex processing plant.

Reduction of use of latex gloves in food handlers: an intervention study.

PubMed

Lee, A; Nixon, R; Frowen, K

2001-02-01

Frequent latex glove use is a risk factor for the development of latex allergy. With the increase in latex glove use, latex allergy has become more prevalent. There are a number of occupational groups in which the use of latex gloves is both inappropriate and even hazardous, including food handlers, where the hazard relates particularly to their latex-sensitive customers. The aim of this study was to assess both the use of latex gloves by food handlers and the impact of an intervention study on reducing latex glove use. This was done at the Queen Victoria Market in Melbourne, Australia. We found that 10 out of 30 stalls (33%) used latex gloves, and that following a short education program, this was reduced to 1 stall (3%, p=0.006). The potential to reduce latex glove use by using this intervention study was 93% (95% confidence interval of 54%-100%). We recommend that food handlers be educated during their training, not only about hygiene issues, but also about the appropriate type of glove to wear, in order to prevent both the development of a new occupational group at risk of becoming allergic to latex, but more importantly to protect their latex-sensitive customers.

Degradation of polyisoprene rubber by newly isolated Bacillus sp. AF-666 from soil.

PubMed

Shah, A A; Hasan, F; Shah, Z; Mutiullah; Hameed, A

2012-01-01

Various microorganisms were screened for their ability to degrade polyisoprene rubber (natural rubber latex gloves). Strain AF-666, newly isolated from a soil sample, was selected as the best strain having the ability to grow on polyisoprene containing plates. The strain identified as Bacillus sp. AF-666, was found to degrade polyisoprene rubber, both on basal agar plates (latex overlay) as well as in liquid medium. Qualitative analysis of degradation was done through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy SEM showed changes in surface morphology, like appearance of pits and cracks, and marked difference in transmittance spectra of test and control due to changes in the functional groups, was detected through FTIR. CO2 evolution as a result of rubber degradation, was calculated gravimetrically by Sturm Test. About 4.43 g/1 of CO2 was produced in case of test, whereas, 1.57 g/1 in case of control. The viable number of cells (CFU/ml) was also higher in test than in control. Present study may provide an opportunity for further studies on the applications of biotechnological processes as a tool for rubber waste management.

Biodegradation of cis-1,4-Polyisoprene Rubbers by Distinct Actinomycetes: Microbial Strategies and Detailed Surface Analysis

PubMed Central

Linos, Alexandros; Berekaa, Mahmoud M.; Reichelt, Rudolf; Keller, Ulrike; Schmitt, Jürgen; Flemming, Hans-Curt; Kroppenstedt, Reiner M.; Steinbüchel, Alexander

2000-01-01

Several actinomycetes isolated from nature were able to use both natural rubber (NR) and synthetic cis-1,4-polyisoprene rubber (IR) as a sole source of carbon. According to their degradation behavior, they were divided into two groups. Representatives of the first group grew only in direct contact to the rubber substrate and led to considerable disintegration of the material during cultivation. The second group consisted of weaker rubber decomposers that did not grow adhesively, as indicated by the formation of clear zones (translucent halos) around bacterial colonies after cultivation on NR dispersed in mineral agar. Taxonomic analysis of four selected strains based on 16S rRNA similarity examinations revealed two Gordonia sp. strains, VH2 and Kb2, and one Mycobacterium fortuitum strain, NF4, belonging to the first group as well as one Micromonospora aurantiaca strain, W2b, belonging to the second group. Schiff's reagent staining tests performed for each of the strains indicated colonization of the rubber surface, formation of a bacterial biofilm, and occurrence of compounds containing aldehyde groups during cultivation with NR latex gloves. Detailed analysis by means of scanning electron microscopy yielded further evidence for the two different microbial strategies and clarified the colonization efficiency. Thereby, strains VH2, Kb2, and NF4 directly adhered to and merged into the rubber material, while strain W2b produced mycelial corridors, especially on the surface of IR. Fourier transform infrared spectroscopy comprising the attenuated total reflectance technique was applied on NR latex gloves overgrown by cells of the Gordonia strains, which were the strongest rubber decomposers. Spectra demonstrated the decrease in number of cis-1,4 double bonds, the formation of carbonyl groups, and the change of the overall chemical environment, indicating that an oxidative attack at the double bond is the first metabolic step of the biodegradation process. PMID:10742254

Knitted outer gloves in primary hip and knee arthroplasty.

PubMed

Tanner, J; Wraighte, P; Howard, P

2006-01-01

A randomised trial was carried out to determine the rate of perforation to inner gloves when comparing latex with knitted gloves during hip and knee arthroplasty. Members of the surgical team were randomised to wear either two pairs of latex gloves (standard double gloving) or a knitted glove on top of a latex glove. In addition, participants completed a visual analogue assessment of their overall satisfaction with the gloves. A total of 406 inner gloves were tested for perforations over a four-month period: 23% of inner gloves were perforated when latex outer gloves were used and 6% of inner gloves were perforated when knitted outer gloves were used. In total, there were 64 perforations to the inner gloves; only one of these perforations was detected by the glove wearer. Wearing knitted outer gloves during hip and knee arthroplasty statistically significantly reduces the risk of perforation to inner latex gloves (p<0.0001).

[Prevention of work-related latex allergy].

PubMed

Mehlum, I S

1998-09-10

Latex allergy has become a common work-related disease among health care workers. An increase in the use of latex gloves is the main reason for this. Measures to prevent sensitization and allergic reactions to latex can be implemented at various administrative levels: at national and international levels by regulations and recommendations, and by the implementation of various measures at the place of work. When to use gloves and what gloves to use are important issues, balancing barrier properties and the need to prevent infection with the need to prevent sensitization and allergic reactions to latex. There are great variations between allergen levels in different gloves, and this can be measured in different ways. Threshold levels are not specified, and latex gloves should not be considered devoid of allergenic potential. The Norwegian Labour Inspection Authority has carried out a survey on latex gloves, based on information from manufacturers and importers, and present this survey to guide glove users. We recommend powder-free gloves with low levels of latex allergens/leachable proteins, chemicals and endotoxins. There are several low-allergen gloves available on the Norwegian market, but for some gloves we lack important information.

Latex-induced occupational asthma: time trend in incidence and relationship with hospital glove policies.

PubMed

Vandenplas, O; Larbanois, A; Vanassche, F; François, S; Jamart, J; Vandeweerdt, M; Thimpont, J

2009-03-01

Natural rubber latex (NRL) has become as a major cause of occupational asthma (OA) in workers using NRL gloves. Few population-based studies have assessed the impact of changes in the patterns of glove usage on the incidence of NRL-induced OA. To characterize the time trends in incident cases of NRL-induced OA in Belgium and examine whether incidence rates were related to the types of gloves used in hospitals. Incident cases of NRL-induced OA were identified through a retrospective review of all claims submitted to the Workers' Compensation Board up to December 2004. Based on the results of diagnostic procedures, the diagnosis of NRL-induced OA was categorized as definite, probable, unlikely, or indeterminate. The patterns of glove usage were characterized through a questionnaire survey of Belgian hospitals. A total of 298 claims for NRL-induced OA were identified, including 127 subjects with definite OA and 68 with probable OA. Categorized by the year of asthma onset, the incident cases of definite and probable NRL-induced OA markedly decreased from 1999 onwards. The use of powdered NRL gloves fell from 80.9% in 1989 to 17.9% in 2004. Powdered NRL gloves were predominantly substituted with NRL-free gloves, especially in the case of non-sterile procedures. These national compensation-based data confirm that a persistent decline in the incidence of NRL-induced OA has occurred since late 1990s. This downward trend has temporally been associated with a decreasing usage of powdered NRL, further supporting a beneficial role of changes in glove policies.

Degradation of latex and of natural rubber by Streptomyces strain La 7.

PubMed

Gallert, C

2000-10-01

Streptomyces strain La 7 was isolated from the banquete of a city high way in Karlsruhe. According to partial 16S rRNA gene sequencing it was identical with Streptomyces albogriseolus and Streptomyces viridodiastaticus. DNA-DNA-similarity studies revealed 80.3-82.4% similarity between each of two of the three strains. Although phylogenetically closely related, Streptomyces strain La 7 differed from the two reference strains by morphological as well as physiological features and might represent a new species aside of S. albogriseolus and S. viridodiastaticus. The new Streptomyces strain La 7 was grown in a medium containing a latex emulsion or squares of natural rubber gloves as the only carbon source. On agar plates with a latex overlay agar, translucent halo formation around the colonies was observed. The unvulcanized latex was metabolized and the carbon from the isoprene units was apparently used for cell growth. In shake cultures with unlimited oxygen supply, during 60 days of incubation, 140 mg of the 175 mg totally emulgated latex were degraded exponentially. In sterile control flasks about 3% of the initial amount of latex could not be recovered after incubation on a shaker, presumably due to photochemical transformation. During static incubation of sterile medium, the latex formed a sticky layer at the surface of the medium and on the glass walls and recovery of the material was more difficult. Estimation of the protein content of cells from total nitrogen resulted in about 50% of the degraded latex being incorporated into cells, if a standard cell composition was assumed. Direct protein analysis according to Bradford (1976) gave much lower estimates, presumably due to a low content of aromatic amino acids. Stripes of natural rubber were degraded by Streptomyces strain La 7 during 70 days to an extent of about 30%. Scanning electron microscopy demonstrated, that hyphes of Streptomyces strain La 7 colonized and penetrated the latex surface with a concomitant deterioration of the latex material.

Studies on the preparation and uses of Co-60 gamma-ray irradiated natural latex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kartowardoyo, S.; Sundardi, F.

1977-11-01

The properties are described of low-ammonia latex concentrates produced by gamma-ray irradiation (0.5 to 2.0 Mrad dose) in the presence of carbon tetrachloride or chloroform as sensitizer. Dipping trails with irradiated concentrates and irradiated field latex, for the preparation of condoms and medical gloves, gave products with high ultimate elongation, low modulus, and high permanent set. A change from straight dipping to coagulant dipping and a heat treatment after drying resulted in improved physical properties. A notable feature of products prepared from these materials is their purity, i.e., low content of rubber chemicals. An economic disadvantage, at the present time,more » is the high initial cost of the irradiation equipment.« less

Prevalence of latex hypersensitivity among health care workers in Malaysia.

PubMed

Shahnaz, M; Azizah, M R; Hasma, H; Mok, K L; Yip, E; Ganesapillai, T; Suraiya, H; Nasuruddin, B A

1999-03-01

Health care workers have been reported to constitute one of the few high-risk groups related to IgE-mediated hypersensitivity associated with the use of latex products. This paper describes the first ever study of prevalence carried out in Malaysia among these workers. One hundred and thirty health care personnel from Hospital Kuala Lumpur were skin tested. Extracts used were prepared from seven different brands of natural rubber latex gloves with varying levels of extractable protein (EPRRIM). Out of the 130 volunteers, 4 (3.1%) had positive skin test to latex with extracts with high levels of EPRRIM (> 0.7 mg/g). The prevalence among the Malaysian health care workers can be considered to be low in comparison to that of some consumer countries as the USA which reported a prevalence of as high as 16.9%.

Reliability and performance of innovative surgical double-glove hole puncture indication systems.

PubMed

Edlich, Richard F; Wind, Tyler C; Heather, Cynthia L; Thacker, John G

2003-01-01

During operative procedures, operating room personnel wear sterile surgical gloves designed to protect them and their patients against transmissible infections. The Food and Drug Administration (FDA) has set compliance policy guides for manufacturers of gloves. The FDA allows surgeons' gloves whose leakage defect rates do not exceed 1.5 acceptable quality level (AQL) to be used in operating rooms. The implications of this policy are potentially enormous to operating room personnel and patients. This unacceptable risk to the personnel and patient could be significantly reduced by the use of sterile double surgical gloves. Because double-gloves are also susceptible to needle puncture, a double-glove hole indication system is urgently needed to immediately detect surgical needle glove punctures. This warning would allow surgeons to remove the double-gloves, wash their hands, and then don a sterile set of double-gloves with an indication system. During the last decade, Regent Medical has devised non-latex and latex double-glove hole puncture indication systems. The purpose of this comprehensive study is to detect the accuracy of the non-latex and latex double-glove hole puncture indication systems using five commonly used sterile surgical needles: the taper point surgical needle, tapercut surgical needle, reverse cutting edge surgical needle, taper cardiopoint surgical needle, and spatula surgical needle. After subjecting both the non-latex and latex double-glove hole puncture indication systems to surgical needle puncture in each glove fingertip, these double-glove systems were immersed in a sterile basin of saline, after which the double-gloved hands manipulated surgical instruments. Within two minutes, both the non-latex and latex hole puncture indication systems accurately detected needle punctures in all of the surgical gloves, regardless of the dimensions of the surgical needles. In addition, the size of the color change visualized through the translucent outer glove did not correlate with needle diameter. On the basis of this extensive experimental evaluation, both the non-latex and latex double-glove hole puncture indication systems should be used in all operative procedures by all operating room personnel.

Latex Allergies: A Review of Recognition, Evaluation, Management, Prevention, Education, and Alternative Product Use

PubMed Central

Schroyer, Traci; Catalfano, Jennifer

2003-01-01

Objectives: To provide information about latex allergies; to determine how to recognize, evaluate, and manage emergencies related to latex allergies; and how to identify those at risk for latex allergies. Additionally, ways to prevent latex exposure, to educate health care workers and athletes about latex allergy, and to provide safe alternatives to latex are investigated. Data Sources: We searched MEDLINE and SPORT Discus for the years 1998–2002 using the key words latex, allergies, rubber, anaphylaxis, gloves, cross-reaction, IgE (immunoglobulin G) proteins, and radioallergosorbent test (RAST). Background: Latex, a sap from the rubber tree, is found in many products used in everyday life. Latex is composed of compounds that may cause an allergic reaction, whose severity can range from irritant dermatitis to type IV dermatitis to type I systemic reaction. Recognition of the signs and symptoms associated with these reactions by the health care professional may help to prevent a more severe reaction from occurring. Reactions can be complicated by contact with other substances, thus causing a cross-reaction. Some individuals are more at risk of latex allergies due to repetitive exposure to latex through their career paths, multiple surgeries, other allergies, or respiratory conditions. Management of an acute reaction involves removal of the irritant, cleansing of the affected area, monitoring vital signs for changes, and seeking additional medical assistance as warranted. Recommendations: Those at risk may be identified through a thorough medical history and allergy testing. Prevention techniques and guidelines are examined, with an emphasis on education at multiple levels. Product information for nonlatex equipment and supplies for the athletic training room is offered, with additional resource information provided. PMID:16558678

Changes in chemical permeation of disposable latex, nitrile, and vinyl gloves exposed to simulated movement.

PubMed

Phalen, Robert N; Le, Thi; Wong, Weng Kee

2014-01-01

Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. The aim of this study was to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time (BT) was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. Glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves.

Changes in Chemical Permeation of Disposable Latex, Nitrile and Vinyl Gloves Exposed to Simulated Movement

PubMed Central

Phalen, Robert N.; Le, Thi; Wong, Weng Kee

2014-01-01

Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. This study was aimed to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. In conclusion, glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves. PMID:24689368

Latex allergy diagnosis: in vivo and in vitro standardization of a natural rubber latex extract.

PubMed

Turjanmaa, K; Palosuo, T; Alenius, H; Leynadier, F; Autegarden, J E; André, C; Sicard, H; Hrabina, M; Tran, T X

1997-01-01

For the diagnosis of IgE-mediated (immediate) hypersensitivity to natural rubber latex (NRL), skin prick testing with extracts of latex gloves has been widely used, but such extracts are difficult to standardize. The present study aimed to produce on an industrial scale an NRL extract from freshly collected NRL and to evaluate, calibrate, and standardize the extract by both in vivo and in vitro testing. The source material, latex of the rubber tree, Hevea brasiliensis (clone RRIM 600), was frozen immediately after collection in Malaysia and shipped in dry ice to Stallergènes SA, France. Protein and allergen profiles were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, isoelectric focusing (IEF), crossed immunoelectrophoresis (CIE), and crossed radioimmunoelectrophoresis (CRIE). Allergen quantification was effected by RAST inhibition. The capacity of the preparation to elicit immediate hypersensitivity reactions in vivo was measured by skin prick testing in 46 latex-allergic patients and 76 nonallergic control subjects. SDS-PAGE and immunoblot profiles of the extract and an NRL standard (E8) provided by the US Food and Drug Administration were almost identical, disclosing several distinct IgE-binding proteins with apparent molecular weights of 14, 20, 27, 30, and 45 kDa, conforming to reported molecular weights of several significant NRL allergens. An arbitrary index of reactivity (IR) of 100 was assigned to the extract at 1:200 dilution (w/v), having a protein content of 22 micrograms/ml. Skin prick testing of latex-allergic patients and controls using the extract at 100 IR revealed 93% sensitivity, 100% specificity, 100% negative predictive value, and 96% positive predictive value. In conclusion, a skin prick test reagent for diagnosis of type I NRL allergy was successfully standardized. The reagent was demonstrated to contain most, if not all, of the currently known clinically significant NRL allergens, and it showed high sensitivity and specificity.

Reduction of antigenic protein levels in latex gloves after gamma irradiation.

PubMed

Zehr, B D; Gromelski, S; Beezhold, D

1994-01-01

Gamma irradiation is currently the method most commonly used to sterilize surgical gloves. In this study, the effect of gamma irradiation on antigenic proteins in latex gloves was examined. Protein extraction and quantitation were carried out using latex gloves before and after sterilization. Antigenic protein levels were determined by an ELISA assay specific for latex proteins (LEAP). LEAP analysis revealed a significant decrease after gamma-irradiation sterilization. This observation may partially explain the lower levels of extractable antigenic proteins found in sterile surgical gloves compared with nonsterile examination gloves. However, gamma irradiation was less effective than autoclave sterilization in reducing protein levels.

Permeability of latex gloves after contact with dental materials.

PubMed

Richards, J M; Sydiskis, R J; Davidson, W M; Josell, S D; Lavine, D S

1993-09-01

The use of latex examination gloves in the dental office has become the standard of care. However, the effectiveness of gloves as a barrier after coming into contact with specific dental materials is still uncertain. To examine the effects of dental materials is still uncertain. To examine the effects of dental materials on latex, 100 latex examination glove finger tips were divided into 10 groups. Each group was manipulated in a different dental material for 15 minutes. Permeability was detected by the passage of herpes virus across the latex membrane, rinsed from the inner glove surface and titrated onto Vero cells. Significant virus leakage was discovered in gloves treated with acrylic monomer, chloroform, and orange solvent. Little virus leakage was noted in bleach, soap, and 30% phosphoric acid etchant treated gloves, and no virus leakage was found with composite resin, ethanol, formocresol, and water treated gloves. These data were supported with scanning electron micrographs taken of the treated glove samples and comparing with the controls. When certain dental materials are manipulated while wearing gloves, irreversible damage to the material occurs and may increase the practitioner's exposure to pathogens.

Latex allergens in tire dust and airborne particles.

PubMed Central

Miguel, A G; Cass, G R; Weiss, J; Glovsky, M M

1996-01-01

The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in debris deposited from the atmosphere near a freeway, and in airborne particulate matter samples representative of the entire year 1993 at two sites in the Los Angeles basin (California). After extraction of the samples with phosphate buffered saline, a modified-ELISA inhibition assay was used to measure relative allergen potency and Western blot analyses were used to identify latex allergens. The inhibition studies with the human IgE latex assay revealed inhibition by the tire tread source samples and ambient freeway dust, as well as by control latex sap and latex glove extracts. Levels of extractable latex allergen per unit of protein extracted were about two orders of magnitude lower for tire tread as compared to latex gloves. Western blot analyses using binding of human IgE from latex-sensitive patients showed a band at 34-36 kDa in all tire and ambient samples. Long Beach and Los Angeles, California, air samples showed four additional bands between 50 and 135 kDa. Alternative Western blot analyses using rabbit IgG raised against latex proteins showed a broad band at 30-50 kDa in all samples, with additional bands in the urban air samples similar to the IgE results. A latex cross-reactive material was identified in mountain cedar. In conclusion, the latex allergens or latex cross-reactive material present in sedimented and airborne particulate material, derived from tire debris, and generated by heavy urban vehicle traffic could be important factors in producing latex allergy and asthma symptoms associated with air pollution particles. Images Figure 1. Figure 2. A Figure 2. B Figure 3. Figure 4. PMID:8959407

Investigation of X-ray permeability of surgical gloves coated with different contrast agents

PubMed Central

Kayan, Mustafa; Yaşar, Selçuk; Saygın, Mustafa; Yılmaz, Ömer; Aktaş, Aykut Recep; Kayan, Fatmanur; Türker, Yasin; Çetinkaya, Gürsel

2016-01-01

Objective: We aimed to investigate the effectiveness and radiation protection capability of latex gloves coated with various contrast agents as an alternative to lead gloves. Methods: The following six groups were created to evaluate the permeability of X-ray in this experimental study: lead gloves, two different non-ionic contrast media (iopromide 370/100 mg I/mL and iomeprol 400/100 mg I/mL), 10% povidone–iodine (PV–I), 240/240 g/mL barium sulphate and a mixture of equal amounts of all contrast agents. A radiation dose detector was placed in coated latex gloves for each one. The absorption values of radiation from latex gloves coated with various contrast agents were measured and compared with the absorption of radiation from lead gloves. This study was designed as an ‘experimental study’. Results: The mean absorption value of X-ray from lead gloves was 3.0±0.08 µG/s. The mean absorption values of X-ray from latex gloves coated with various contrast agents were 3.7±0.09 µG/s (iopromide 370/100 mg I/mL), 3.6±0.09 µG/s (iomeprol 400/100 mg I/mL), 3.7±0.04 µG/s (PV–I), 3.1±0.07 µG/s (barium sulphate) and 3.8±0.05 µG/s (mixture of all contrast agents). Latex gloves coated with barium sulphate provided the best radiation absorption compared with latex gloves coated with other radiodense contrast agents. Conclusion: Latex gloves coated with barium sulphate may provide protection equivalent to lead gloves. PMID:26680548

Glove-derived foreign proteins induce allergen-specific IgE in a mouse model.

PubMed

Busch, Marion; Schröder, Claudia; Baron, Jens-Malte; Ott, Hagen; Bruckner, Thomas; Diepgen, Thomas L; Mahler, Vera

2008-04-01

Currently, most medical gloves are produced with a low content of natural rubber latex (NRL) protein. However, they may be substituted by proteins of foreign origin to maintain specific properties of the material. The aim of this study was to investigate the allergenicity and immunogenicity of unexpected proteins (i.e., soy and casein) compared with NRL proteins in a murine model in BALB/c mice. All respective allergen sources (extracts from three brands of NRL gloves, soy, and casein) were able to induce significant allergen-specific IgE and IgG(1) responses. On average, the highest IgE induction occurred after immunization with NRL, followed by soy and casein. Certain individuals from each treatment group exhibited levels of specific IgE as high as due to NRL. To analyze further specific IgE responses on a single allergen level, we established a microarray based on recombinant allergens for allergen-specific murine IgE detection. Besides specific IgE against rHev b 3, -6, -7, -8, and -11, specific IgE against kappa-casein could be detected in mice immunized with NRL glove extract, indicating a sensitization potential of the contained foreign protein. The substitution of genuine latex proteins by proteins of foreign origin may lead to a shift and de novo increase in sensitization to the finished products.

Latex allergy: epidemiological study of 1351 hospital workers.

PubMed

Liss, G M; Sussman, G L; Deal, K; Brown, S; Cividino, M; Siu, S; Beezhold, D H; Smith, G; Swanson, M C; Yunginger, J; Douglas, A; Holness, D L; Lebert, P; Keith, P; Wasserman, S; Turjanmaa, K

1997-05-01

To determine the prevalence of latex sensitisation among a large group of healthcare workers, study the occupational and non-occupational factors associated with latex allergy, and characterise latex exposure in air and by gloves. All 2062 employees of a general hospital in Hamilton, Ontario, Canada who regularly used latex gloves were invited to participate in a cross sectional survey, representing the baseline phase of a prospective cohort morbidity study. Attempts were made to recruit employees who were diagnosed with latex allergy before the survey. Glove extracts were assayed for antigenic protein, and area and personal air samples were obtained on two occasions (summer and winter) to estimate exposure to airborne latex protein. A questionnaire on medical and occupational information was administered by an interviewer. Skin prick tests were performed with latex reagents, three common inhalants, and six foods. The mean (SD) latex protein concentrations were 324 (227) micrograms/g in powdered surgical gloves and 198 (104) micrograms/g in powdered examination gloves. Personal latex aeroallergen concentrations ranged from 5 to 616 ng/m3. There was a total of 1351 (66%) participants. The prevalence of positive latex skin tests was 12.1% (95% confidence interval (95% CI) 10.3% to 13.9%). This prevalence did not vary by sex, age, hospital, or smoking status but subjects who were latex positive were significantly more likely to be atopic (P < 0.01). Participants who were latex positive were also significantly more likely to have positive skin tests to one or more foods (Mantel-Haenszel odds ratio (OR) adjusted for atopy 12.1, 95% CI 7.6 to 19.6, P < 10(-9)). Work related symptoms were more often reported among latex positive people, and included hives (OR 6.3, 95% CI 3.2 to 12.5), eye symptoms (OR 1.9, 95% CI 1.2 to 2.8), and wheezy or whistling chest (OR 4.7, 95% CI 2.8 to 7.9). The prevalence of latex sensitivity was highest among laboratory workers (16.9%), and nurses and physicians (13.3%). When the glove consumption per healthcare worker for each department was grouped into tertiles, the prevalence of latex skin test positivity was greater in the higher tertiles of glove use for sterile (surgical) gloves (P < 0.005) but not for examination gloves. In this large, cross sectional study of healthcare workers, the prevalence of latex sensitisation was 12.1% (9.5% among all those eligible), and there were significant associations with atopy, positive skin tests to certain foods, work related symptoms, and departmental use of gloves per healthcare worker. This cohort is being followed up prospectively and will be retested to determine the incidence of development of latex sensitivity.

Latex Allergy

MedlinePlus

... the material touches the skin. This is called contact dermatitis. Red, itchy bumps or blisters usually appear within ... powdered gloves are used and avoid all direct contact with latex. ... to get a skin rash reaction to latex, latex gloves made without additional ...

Home Healthcare Workers: How to Prevent Latex Allergies

MedlinePlus

... delayed hypersensitivity) This skin reaction looks like the rash from contact with poison ivy and usually shows up 24– ... after using gloves. • Recognize symptoms of latex allergy (rash; hives; flushing; ... Avoid direct contact with latex gloves and other latex-containing products ...

Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production.

PubMed

Wang, Xuchu; Wang, Dan; Sun, Yong; Yang, Qian; Chang, Lili; Wang, Limin; Meng, Xueru; Huang, Qixing; Jin, Xiang; Tong, Zheng

2015-09-08

Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production.

Cream concentrated latex for foam rubber products

NASA Astrophysics Data System (ADS)

Suksup, R.; Imkaew, C.; Smitthipong, W.

2017-12-01

Fresh natural latex (around 40% rubber and 60% water) can be transformed to concentrated natural latex (around 60% rubber and 40% water) in order to realise economical transportation and easier latex product’s preparation. The concentrated natural latex is an extremely valuable material. It can be applied for many types of products, for example, foam rubber as pillow and mattress, elastic band, etc. Industrially, the concentrated natural latex can be prepared by centrifugation which requires an enormous expensive machine. From the eco-friendly products point of view, most of rubber entrepreneurs in the world try to develop a green rubber product. So, the main objective of this study is to prepare the cream concentrated latex without any sophisticated machine. Thus, we work on a simple, cheap and green method that does not use any expensive machine but uses water-based chemical as sodium alginate to prepare the cream concentrated latex. The optimal amount of sodium alginate in the latex was studied. The main characteristics of the cream concentrated latex were tested by various technics, such as alkalinity, total solid content (TSC), dry rubber content (DRC), etc. We found that there are no significant differences of results between fresh natural latex and cream concentrated latex, except for the TSC and DRC. The TSC and DRC of cream latex are higher than those of fresh natural latex. Finally, we propose a model of natural rubber particle and sodium alginate to form the cream concentrated latex.

Effect of five brands of latex gloves on the setting time of polyvinyl siloxane putty impression materials.

PubMed

Ravikumar, C M; Sangur, Rajashekar

2012-01-01

Addition silicone impression materials have been used as impression material for more than 20 years. Although they are among the most expensive impression materials, they became popular during the past decade as they have excellent physical properties. Prevention of infection is an important aspect in dental treatment since dental professionals are routinely exposed to the wide variety of microorganisms present in saliva. Gloves are the most common protective measure used during dental treatment. The gloves are mostly made of latex. In this study, we examine how the setting time of three types polyvinyl putty materials were affected by the use of five different brands of latex gloves and one brand of vinyl gloves. Each material was first mixed without wearing gloves according to the manufacturer's instructions. After the stipulated mixing time, the setting time was measured using the Vicat needle. The setting time is measured from the time of mixing till the time that the needle does not produce any indentation on the surface of the material. The putty material was then mixed with gloved hands (using the five different brands of latex gloves in turn) and the setting time was measured. Then the material was mixed with washed gloved hands, and the setting time was measured again. Finally, the material was mixed with vinyl gloved hands and the setting time was measured. The following conclusions were drawn from the study: Reprosil and Express showed significant variation in the setting time with the latex gloved hands.There was no significant variation in the setting time when material was mixed with unwashed vs washed gloved hands.Vinyl gloves did not significantly affect the setting time of any of the putty impression materials.

Estimated exposure of hands inside the protective gloves used by non-occupational handlers of agricultural pesticides.

PubMed

Beránková, Martina; Hojerová, Jarmila; Peráčková, Zuzana

2017-11-01

Exposure of handlers'/operators' hands is a main route of agricultural pesticides entry into their body. Non-occupational handlers still lack information about appropriate selection of protective gloves to minimize exposure and reduce adverse effects of these chemicals. According to the results of our previous survey, six commercially available, water-resistant gloves commonly used by non-professional gardeners were evaluated for permeation of Acetamiprid, Pirimicarb, and Chlorpyrifos-methyl (Chlorp-m) pesticides by means of in vitro testing. In-use conditions were mimicked as close as possible. Chlorp-m through latex was observed inside the glove from >10 to ⩽15 min; however, Acetamiprid and Pirimicarb through neoprene/latex and all the three pesticides through butyl were not observed inside gloves for the duration of the experiments (the Breakthrough time (BT)>8 h). The 1-h exposure proved the interior glove contamination with Chlorp-m through disposable latex, vinyl, and nitrile gloves (51, 33, and 41% of applied dose (AD), respectively) just as with Acetamiprid and Pirimicarb through latex glove (11 and 14%AD, respectively). However, when storing the used gloves for 4 days after the exposure, no release of the three pesticides from the butyl and Acetamiprid from neoprene/latex gloves was detected. In all other cases, pesticides were found in the interior glove (36-79, 31-63, and 51-81%AD for Acetamiprid, Pirimicarb, and Chlorp-m, respectively). If used repeatedly, gloves contaminated in this way lose their protective function but give the user a false sense of security. The results suggest that (i) water-resistant gloves are not necessarily pesticide resistant; (ii) disposable latex gloves commonly worn by non-professional gardeners provide inadequate protection even for a short-time contact with pesticides; (iii) to assess the efficiency of reusable gloves, not only BT value but also the reservoir/release effect of parent pesticide and its degradation products should be evaluated; and (iv) awareness-raising activities for non-occupational handlers of pesticides should be enhanced.

30 CFR 77.606-1 - Rubber gloves; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... COAL MINES Trailing Cables § 77.606-1 Rubber gloves; minimum requirements. (a) Rubber gloves (lineman's gloves) worn while handling high-voltage trailing cables shall be rated at least 20,000 volts and shall... gloves (wireman's gloves) worn while handling trailing cables energized by 660 to 1,000 volts shall be...

Understanding Factors that Influence Protective Glove Use among Automotive Spray Painters

PubMed Central

Ceballos, Diana; Reeb-Whitaker, Carolyn; Glazer, Patricia; Murphy-Robinson, Helen; Yost, Michael

2017-01-01

Dermal contact with isocyanate-based coatings may lead to systemic respiratory sensitization. The most common isocyanates found in sprayed automotive coatings are monomeric and oligomeric 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). Most spray painters use thin (4–5 mil) latex gloves that are not effective at preventing dermal exposures when spraying isocyanate paints. Personal interviews with collision repair industry personnel and focus groups with spray painters were held to characterize risk awareness, to examine perceptions and challenges concerning protective glove use and selection, and to generate ideas for protective glove use interventions. The most popular gloves among spray painters were thin (4–5 mil) and thick (14 mil) latex. We found that medium to thick (6–8 mil) nitrile were not always perceived as comfortable and were expected to be more expensive than thin (4–5 mil) latex gloves. Of concern is the users’ difficulty to distinguish between nitrile and latex gloves; latex gloves are now sold in different colors including blue, which has traditionally been associated with nitrile gloves. Even though spray painters were familiar with the health hazards related to working with isocyanate paints; most were not always aware that dermal exposure to isocyanates could contribute to the development of occupational asthma. There is a need for more research to identify dermal materials that are protective against sprayed automotive coatings. Automotive spray painters and their employers need to be educated in the selection and use of protective gloves, specifically on attributes such as glove material, color, and thickness. PMID:24215135

Fundamentals of the knowledge about chemical additives present in rubber gloves.

PubMed

Oliveira, Hegles Rosa de; Alchorne, Alice de Oliveira de Avelar

2011-01-01

One of the most frequent causes of allergic contact dermatitis of occupational origin are rubber additives, which are present in Personal Protective Equipment (PPE). The most allergenic additives of natural and synthetic gloves are thiurams, carbamates and mercapto group. To investigate the state of knowledge about the chemical additives used in the manufacture of synthetic rubber gloves. This was a qualitative research study in which professionals working in the manufacture, research, prescription and commercialization of gloves answered an open questionnaire. 30 individuals were interviewed: 4 researchers in occupational medicine, 5 occupational physicians, 2 occupational safety technicians, a rubber workers' union physician, an occupational safety engineer, a pro duction engineer of rubber gloves, 4 importers of gloves, a manufacturer of gloves, 3 businessmen who sell PPE, 3 salesclerks working in stores that sell PPE, 2 businessmen who own stores that sell products for allergic individuals, and 3 dermatologists. Knowledge of the chemical composition of rubber gloves is scant. The labeling of gloves, with the description of their chemical composition, would facilitate choosing the best type of glove for each person. This low-cost action to businesses would be a gain from the standpoint of public health, with huge repercussions for users of rubber gloves.

Reinforcement of latex rubber by the incorporation of amphiphilic particles

USDA-ARS?s Scientific Manuscript database

Latex rubbers are fabricated from latex suspensions. During the fabrication process, latex particles are bound together while water is removed from the suspension. This report shows that the mechanical properties of latex rubbers can be improved by incorporating a small amount of amphiphilic submicr...

Blends of guayule natural rubber latex with commercial latex polymers

USDA-ARS?s Scientific Manuscript database

Guayule (Parthenium argentatum) is a woody desert shrub that produces natural rubber, cis-1,4 polyisoprene, by biosynthesis. It is currently cultivated in the southwestern United States as a source of latex and rubber for commercial development. Guayule latex is similar to Hevea latex in polymer mo...

Glove powder's carrying capacity for latex protein: analysis using the ASTM ELISA test.

PubMed

Beezhold, D; Horton, K; Hickey, V; Daddona, J; Kostyal, D

2003-01-01

Glove donning powders carry latex proteins and disperse them into the workplace environment. We have used the ASTM D6499 ELISA to quantify the amount of latex antigen bound to and carried by glove powders. We could differentiate between a small amount of protein actually bound to the powders and a larger amount carried by the powder. Enhanced binding of a major allergen, Hev b 5, to the starch powders was demonstrated by Western blot. The D6499 ELISA is able to measure total latex antigen, soluble and powder bound, simultaneously without the need to centrifuge the samples.

Double gloving to reduce surgical cross-infection.

PubMed

Tanner, J; Parkinson, H

2006-07-19

The invasive nature of surgery, with its increased exposure to blood, means that during surgery there is a high risk of transfer of pathogens. Pathogens can be transferred through contact between surgical patients and the surgical team, resulting in post-operative or blood borne infections in patients or blood borne infections in the surgical team. Both patients and the surgical team need to be protected from this risk. This risk can be reduced by implementing protective barriers such as wearing surgical gloves. Wearing two pairs of surgical gloves, triple gloves, glove liners or cloth outer gloves, as opposed to one pair, is considered to provide an additional barrier and further reduce the risk of contamination. The primary objective of this review was to determine if additional glove protection reduces the number of surgical site or blood borne infections in patients or the surgical team. The secondary objective was to determine if additional glove protection reduces the number of perforations to the innermost pair of surgical gloves. The innermost gloves (next to skin) compared with the outermost gloves are considered to be the last barrier between the patient and the surgical team. We searched the Cochrane Wounds Group Specialised Register (January 2006), and the Cochrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library Issue 4, 2005). We also contacted glove manufacturing companies and professional organisations. Randomised controlled trials involving: single gloving, double gloving, triple gloving, glove liners, knitted outer gloves, steel weave outer gloves and perforation indicator systems. Both authors independently assessed the relevance and quality of each trial. Data was extracted by one author and cross checked for accuracy by the second author. Two trials were found which addressed the primary outcome, namely, surgical site infections in patients. Both trials reported no infections. Thirty one randomised controlled trials measuring glove perforations were identified and included in the review. Fourteen trials of double gloving (wearing two pairs of surgical latex gloves) were pooled and showed that there were significantly more perforations to the single glove than the innermost of the double gloves (OR 4.10, 95% CI 3.30 to 5.09). Eight trials of indicator gloves (coloured latex gloves worn underneath latex gloves to more rapidly alert the team to perforations) showed that significantly fewer perforations were detected with single gloves compared with indicator gloves (OR 0.10, 95% CI 0.06 to 0.16) or with standard double glove compared with indicator gloves (OR 0.08, 95% CI 0.04 to 0.17). Two trials of glove liners (a glove knitted with cloth or polymers worn between two pairs of latex gloves)(OR 26.36, 95% CI 7.91 to 87.82), three trials of knitted gloves (knitted glove worn on top of latex surgical gloves)(OR 5.76, 95% CI 3.25 to 10.20) and one trial of triple gloving (three pairs of latex surgical gloves)(OR 69.41, 95% CI 3.89 to 1239.18) all compared with standard double gloves, showed there were significantly more perforations to the innermost glove of a standard double glove in all comparisons. There is no direct evidence that additional glove protection worn by the surgical team reduces surgical site infections in patients, however the review has insufficient power for this outcome. The addition of a second pair of surgical gloves significantly reduces perforations to innermost gloves. Triple gloving, knitted outer gloves and glove liners also significantly reduce perforations to the innermost glove. Perforation indicator systems results in significantly more innermost glove perforations being detected during surgery.

Latex allergy symptoms among health care workers: results from a university health and safety surveillance system.

PubMed

Epling, Carol; Duncan, Jacqueline; Archibong, Emma; Østbye, Truls; Pompeii, Lisa A; Dement, John

2011-01-01

We sought to describe risk factors for latex glove allergy symptoms among health care workers by combining data from an active clinical surveillance program and a comprehensive occupational health surveillance system. A total of 4,584 employers completed a latex allergy questionnaire. Six percent (n = 276) of subjects reported symptoms consistent with latex allergy. Years of latex glove use was a significant risk factor for latex allergy symptoms even after controlling for the effects of atopy, gender, age, race, fruit, and other allergies. Nurses, medical or lab technicians, physician's assistants, other clinical professionals, and housekeepers had the highest prevalence of latex glove allergy symptoms. Forty subjects (0.87%) who were confirmed as having latex sensitization. Sensitizsation may have been underestimated due to use of specific IgE antibody, less sensitive than skin-prick testing, and tiered design leading to laboratory assessment on a subset of the cohort. This surveillance program identified risk factors for latex allergy symptoms. Our findings provide a basis for tailoring future prevention strategies.

Influence of wearing latex gloves on electric pulp tester readings in children.

PubMed

Holan, G

1993-12-01

Electric pulp testers operated by completing an electric circuit. Latex examination gloves have been claimed to interrupt this circuit and lead to false-negative results. This study was conducted to evaluate the influence of wearing latex gloves on electric pulp tester (EPT) readings. The pulps of 80 maxillary permanent incisors of 22 children 10-13 1/2 years old were tested using the Pelton & Crane 'Vitapulp' instrument. Each tooth was tested twice: with gloves and with bare hands. Teeth failing to respond to the EPT without gloves were excluded from the study. All EPT readings ranged between 1 and 9.5. Five teeth gave the same responses with gloved and ungloved hands. Only five teeth did not respond when gloves were worn, and all of these gave readings near the top of the EPT scale when tested without gloves. The other 70 teeth presented significantly higher readings with gloves than without gloves. It is concluded that removal of examination gloves during the operation of the EPT is necessary only if no response is obtained.

Contact Dermatitis from Penetration of Rubber Gloves by Acrylic Monomer

PubMed Central

Pegum, J. S.; Medhurst, F. A.

1971-01-01

An orthopaedic surgeon developed dermatitis from acrylic materials. The acrylic monomer was found to penetrate surgical rubber gloves readily. Cases of “rubber glove dermatitis” with negative patch tests may have a similar explanation. Laboratory tests suggest that monomer does not damage rubber sufficiently to allow bacteria to penetrate gloves, but it remains possible that this would happen under theatre conditions. PMID:5581492

Performance Analysis of Exam Gloves Used for Aseptic Rodent Surgery

PubMed Central

LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

2015-01-01

Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP–PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham ‘exertion’ activity. According to these criteria, 94% of HP–PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP–PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries. PMID:26045458

Performance analysis of exam gloves used for aseptic rodent surgery.

PubMed

LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

2015-05-01

Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP-PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham 'exertion' activity. According to these criteria, 94% of HP-PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP-PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries.

Use of DSC and DMA to Study Rubber Crystallization as a Possible Cause for a Tear in a Neoprene Glove Used in a Space Shuttle Pressurized Astronaut Suit

NASA Technical Reports Server (NTRS)

Wingard, Doug

2009-01-01

The Advanced Crew Escape Suit (ACES) is a pressurized suit normally worn by astronauts during launch and landing phases of Space Shuttle operations. In 2008, a large tear (0.5 -1 in. long, between the pinky and ring finger) in the ACES left-hand glove made of neoprene latex rubber was found during training for Shuttle flight STS-124. An investigation to help determine the cause(s) of the glove tear was headed by the NASA Johnson Space Center (JSC) in Houston, Texas. Efforts at JSC to reproduce the actual glove tear pattern by cutting/tearing or rupturing were unsuccessful. Chemical and material property data from JSC such as GC-MS, FTIR, DSC and TGA mostly showed little differences between samples from the torn and control gloves. One possible cause for the glove tear could be a wedding ring/band worn by a male astronaut. Even with a smooth edge, such a ring could scratch the material and initiate the tear observed in the left-hand glove. A decision was later made by JSC to not allow the wearing of such a ring during training or actual flight. Another possible cause for the ACES glove tear is crystallinity induced by strain in the neoprene rubber over a long period of time and use. Neoprene is one several elastomeric materials known to be susceptible to crystallization, and such a process is accelerated with exposure of the material to cold temperatures plus strain. When the temperature is lowered below room temperature, researchers have shown that neoprene crystallization may be maintained at temperatures as high as 45-50 F, with a maximum crystallization rate near 20-25 F (1). A convenient conditioning temperature for inducing neoprene crystallization is a typical freezer that is held near 0 F. For work at the NASA Marshall Space Flight Center (MSFC), samples were cut from several areas/locations (pinky/ring finger crotch, index finger and palm) on each of two pairs of unstrained ACES gloves for DSC and DMA thermal analysis testing. The samples were conditioned in a freezer for various times up to about 14 days. Some rectangular conditioned samples were unstrained, while most were subjected to strains up to 250% with the aid of two slotted aluminum blocks and two aluminum clamps per sample. Trends were observed to correlate DSC data (heat of fusion) and DMA data (linear CTE and stress for iso-strain testing) with: (a) sample location on each glove; and (b) level of strain during conditioning. Control samples cut as is from each glove location were also tested by DSC and DMA.

Development of optical laser balloon and drainage from radiation vulcanized natural rubber latex

NASA Astrophysics Data System (ADS)

Shimamura, Yoshiyuki

Rubber film made of radiation vulcanized natural rubber latex (RVNRL) has better transparency and lower toxicity compared with sulfur-vulcanized latex film. Optical laser balloon (optical endoscopical balloon) and drainage were developed by using RVNRL. An endoscope was equipped with a saline-filled latex rubber balloon at its tip to displace contaminating blood, bile, or gastric contents during operative portoscopy, biliary endoscopy, or upper gastrointestinal endoscopy. The transmission of Nd-Yag laser through the balloon is 98%, higher than the sulfur-vulcanized latex rubber (75%). High transparency of the drainage bag facilitated easy observation of discharged fluids without detaching the bag from the tube.

Development of a test method for protective gloves against nanoparticles in conditions simulating occupational use

NASA Astrophysics Data System (ADS)

Dolez, Patricia; Vinches, Ludwig; Wilkinson, Kevin; Plamondon, Philippe; Vu-Khanh, Toan

2011-07-01

Nanoparticle manufacture and use are in full expansion. The associated risks of occupational exposure raise large concerns due to their potential toxicity. Even if they stand as a last resort in the traditional occupational Health & Safety (H&S) risk management strategy, personal protective equipment (PPE) against nanoparticles are an absolute need in the context of precautionary principle advocated by H&S organizations worldwide. However no standard test method is currently available for evaluating the efficiency of PPE against nanoparticles, in particular in the case of gloves. A project is thus underway to develop a test method for measuring nanoparticle penetration through protective gloves in conditions simulating glove-nanoparticle occupational interaction. The test setup includes an exposure and a sampling chamber separated by a circular glove sample. A system of cylinders is used to deform the sample while it is exposed to nanoparticles. The whole system is enclosed in a glove box to ensure the operator safety during assembly, dismounting and clean-up operations as well as during the tests. Appropriate nanoparticle detection techniques were also identified. Results are reported here for commercial 15nm TiO2 nanoparticles - powder and colloidal solutions in 1,2-propanediol, ethylene glycol and water - and four types of protective gloves: disposable nitrile and latex as well as unsupported neoprene and butyl rubber gloves. They show that mechanical deformations and contact with colloidal solution liquid carriers may affect glove materials. Preliminary results obtained with TiO2 powder indicate a possible penetration of nanoparticles through gloves following mechanical deformations.

Prospective data collection and analysis of perforations and tears of latex surgical gloves during primary endoprosthetic surgeries.

PubMed

Zaatreh, Sarah; Enz, Andreas; Klinder, Annett; König, Tony; Mittelmeier, Lena; Kundt, Günther; Mittelmeier, Wolfram

2016-01-01

Introduction: Surgical gloves are used to prevent contamination of the patient and the hospital staff with pathogens. The aim of this study was to examine the actual effectiveness of gloves by examining the damage (perforations, tears) to latex gloves during surgery in the case of primary hip and knee prosthesis implantation. Materials and methods: Latex surgical gloves used by surgeons for primary hip and knee replacement surgeries were collected directly after the surgery and tested using the watertightness test according to ISO EN 455-1:2000. Results: 540 gloves were collected from 104 surgeries. In 32.7% of surgeries at least one glove was damaged. Of all the gloves collected, 10.9% were damaged, mainly on the index finger. The size of the perforations ranged from ≤1 mm to over 5 mm. The surgeon's glove size was the only factor that significantly influenced the occurrence of glove damage. Surgeon training level, procedure duration, and the use of bone cement had no significant influence. Conclusions: Our results highlight the high failure rate of surgical gloves. This has acute implications for glove production, surgical practice, and hygiene guidelines. Further studies are needed to detect the surgical steps, surface structures, and instruments that pose an increased risk for glove damage.

Effect of cellulose nanocrystals from corn cob with dispersion agent polyvinyl pyrrolidone in natural rubber latex film after aging treatment

NASA Astrophysics Data System (ADS)

Harahap, H.; Ridha, M.; Halimatuddahliana; Taslim; Iriany

2018-02-01

This study about the resistance of natural rubber latex films using nanocrystals cellulose filler from corn cob waste by aging treatment. Corn cob used as organic filler composed of cellulose, hemicellulose, and lignin. Each component has a potential for reuse, such as cellulose. Cellulose from corn cob has potential application as a filler prepared by hydrolysis process using a strong acid. The producing of natural rubber latex films through coagulant dowsing process. This research started with the pre-vulcanization process of natural rubber latex at 70 °C and followed by process of vulcanization at 110 °C for 20 minutes. Natural rubber latex films that have been produced continued with the aging treatment at 70 °C for 168 hours. The mechanical properties of natural rubber latex films after aging treatment are the tensile strength, elongation at break, M100 and M300 have performed.

The effectiveness of cut-proof glove liners: cut and puncture resistance, dexterity, and sensibility.

PubMed

Salkin, J A; Stuchin, S A; Kummer, F J; Reininger, R

1995-11-01

Five types of commercial glove liners (within double latex gloves) were compared to single and double latex gloves for cut and puncture resistance and for relative manual dexterity and degree of sensibility. An apparatus was constructed to test glove-pseudofinger constructs in either a cutting or puncture mode. Cutting forces, cutting speed, and type of blade (serrated or scalpel blade) were varied and the time to cut-through measured by an electrical conductivity circuit. Penetration forces were similarly determined with a scalpel blade and a suture needle using a spring scale loading apparatus. Dexterity was measured with an object placement task among a group of orthopedic surgeons. Sensibility was assessed with Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry using standard techniques and rating scales. A subjective evaluation was performed at the end of testing. Time to cut-through for the liners ranged from 2 to 30 seconds for a rapid oscillating scalpel and 4 to 40 seconds for a rapid oscillating serrated knife under minimal loads. When a 1 kg load was added, times to cut-through ranged from 0.4 to 1.0 second. In most cases, the liners were superior to double latex. On average, 100% more force was required to penetrate the liners with a scalpel and 50% more force was required to penetrate the liners with a suture needle compared to double latex. Object placement task times were not significantly liners compared to double latex gloves. Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry showed no difference in sensibility among the various liners and double latex gloves. Subjects felt that the liners were minimally to moderately impairing. An acclimation period may be required for their effective use.

Reducing workers' compensation costs for latex allergy and litigation against glove manufacturing companies.

PubMed

Edlich, Richard F; Mason, Shelley S; Swainston, Erin; Dahlstrom, Jill J; Gubler, K; Long, William B

2009-01-01

It has been well documented in the medical literature that powdered medical gloves can have serious consequences to patients and health-care workers. Adverse reactions to natural latex gloves, such as contact dermatitis and urticaria, occupational asthma, and anaphylaxis, have been documented as a significant cause of Workers' Compensation claims among health-care workers. While the cost of examination and surgical gloves is significant, this factor must be considered with the total cost of Workers' Compensation claims and possible litigation bestowed upon hospitals and glove manufacturing companies. In the United States, Canada, Belgium, and Germany, medical leaders have documented the dangers of powdered latex gloves and have implemented transition programs that are reducing Workers' Compensation claims filed by health-care workers. While attorneys view litigation against powdered glove manufacturers as the "next big tort", the authors of this article were not able to document all compensation costs to disabled workers because many settlements do not allow the claimant to disclose this information.

Contamination of Critical Surfaces from NVR Glove Residues Via Dry Handling and Solvent Cleaning

NASA Technical Reports Server (NTRS)

Sovinski, Marjorie F.

2004-01-01

Gloves are often used to prevent the contamination of critical surfaces during handling. The type of glove chosen for use should be the glove that produces the least amount of non-volatile residue (NVR). This paper covers the analysis of polyethylene, nitrile, latex, vinyl, and polyurethane gloves using the contact transfer and gravimetric determination methods covered in the NASA GSFC work instruction Gravimetric Determination and Contact Transfer of Non-volatile Residue (NVR) in Cleanroom Glove Samples, 541-WI-5330.1.21 and in the ASTM Standard E-1731M-95, Standard Test Method for Gravimetric Determination of Non-Volatile Residue from Cleanroom Gloves. The tests performed focus on contamination of critical surfaces at the molecular level. The study found that for the most part, all of the gloves performed equally well in the contact transfer testing. However, the polyethylene gloves performed the best in the gravimetric determination testing, and therefore should be used whenever solvent contact is a possibility. The nitrile gloves may be used as a substitute for latex gloves when latex sensitivity is an issue. The use of vinyl gloves should be avoided, especially if solvent contact is a possibility. A glove database will be established by Goddard Space Flight Center (GSFC) Code 541 to compile the results from future testing of new gloves and different glove lots.

Experimental study on the drying of natural latex medical gloves

NASA Astrophysics Data System (ADS)

Chankrachang, Mano; Yongyingsakthavorn, Pisit; Tohsan, Atitaya; Nontakaew, Udomkiat

2018-01-01

The purpose of this research was to study latex film drying at 70 °C using a laboratory drying oven. Two different total solid content (TSC) latex compounds, which 45% TSC and 35% TSC were used. The undried latex films were prepared according to the common procedures used in latex gloves manufacturers, that is, by dry coagulant dipping process. The experimental results such as initial moisture content, the amount of moisture and drying time of latex films in each latex compound formula were determined. After that, the results were projected to calculate on the production capacity expand by 1 million piece/day of natural latex medical gloves. Finally, the rate of moisture entering the latex drying oven and the energy consumption of the drying oven were estimated. The results indicated that when the 35% TSC of latex compound was used. The initial moisture content of latex film was higher than 45% TSC of latex compound about 7%. The drying time of 35% TSC was longer than 45% TSC for 2.5 min and consume more energy about 10%. As a result, the 45% TSC latex compound was the better way to saving energy and managing humidity in the production line. Therefore, it was found to very useful to an approximate design length and size of actual of latex drying oven and the rate of moisture entering the oven as well.

Glove permeation by semiconductor processing mixtures containing glycol-ether derivatives.

PubMed

Zellers, E T; Ke, H Q; Smigiel, D; Sulewski, R; Patrash, S J; Han, M W; Zhang, G Z

1992-02-01

Results of permeation tests of several glove materials challenged with semiconductor processing formulations containing glycolether derivatives are described. Commercial glove samples of nitrile rubber (Edmont), natural rubber (Edmont and Baxter), butyl rubber (North), PVC Baxter), a natural rubber/neoprene/nitrile blend (Pioneer), and a natural rubber/neoprene blend (Playtex) were tested according to the ASTM F739-85 permeation test method (open-loop configuration). The liquid formulations examined included a positive photoresist thinner containing 2-ethoxyethyl acetate (2-EEA), n-butyl acetate, and xylene; a positive photoresist containing 2-EEA, n-butyl acetate, xylene, polymer resins, and photoactive compounds; a negative photoresist containing 2-methoxyethanol (2-ME), xylene, and cyclized poly(isoprene); and pure 2-methoxyethyl acetate (2-MEA), which is the solvent used in a commercial electron-beam resist. With the exception of the negative photoresist, butyl rubber provided the highest level of protection against the solvent mixtures tested, with no breakthrough observed after 4 hr of continuous exposure at 25 degrees C. Nitrile rubber provided the highest level of protection against the negative photoresist and reasonably good protection against initial exposure to the other solvent mixtures. Gloves consisting of natural rubber or natural rubber blends provided less protection against the mixtures than either nitrile or butyl rubber. For most of the glove samples, permeation of the glycol-ether derivatives contained in the mixtures was faster than that predicted from the permeation of the pure solvents. Increasing the exposure temperature from 25 to 37 degrees C did not significantly affect the performance of the butyl rubber glove. For the other gloves, however, exposures at 37 degrees C resulted in decreases in breakthrough times of 25-75% and increases in steady-state permeation rates of 80-457% relative to values obtained at 25 degrees C. Repeated exposure of nitrile rubber samples resulted in shorter breakthrough times for all mixture components. In fact, exposure for as little as one-half of the nominal breakthrough time followed by air drying overnight resulted in measurable quantities of one or more of the component solvents at the inner surface of the gloves at the beginning of the next exposure. This effect was not observed with the butyl rubber samples. With the exception of the negative photoresist, heating previously exposed nitrile rubber samples at 70 degrees C for 20 hr prior to retesting reduced or eliminated the effects of residual solvents, permitting reuse of the gloves. The use of thin PVC or natural rubber gloves adjacent to the nitrile gloves provided moderate increases in permeation resistance.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of wearing knitted or rubber gloves on the transfer of Escherichia cohi between hands and meat.

PubMed

Gill, C O; Jones, T

2002-06-01

On eight occasions, five volunteers each handled five pieces of meat with bare hands or while wearing dry or wet knitted gloves or rubber gloves after hands had been inoculated with Escherichia coli or after handling a piece of meat inoculated with E. coli. On each occasion, after all meat was handled, each piece of meat, glove, and hand were sampled to recover E. coli. When hands were inoculated, E. coli was recovered from all meat handled with bare hands, in lesser numbers from some pieces handled with knitted gloves, and from only one piece handled with rubber gloves. When pieces of inoculated meat were handled, the numbers of E. coli transferred to uninoculated meat from bare hands or rubber gloves decreased substantially with each successive piece of uninoculated meat, but decreases were small with knitted gloves. The findings indicate that, compared with bare hands, the use of knitted gloves could reduce the transfer of bacteria from hands to meat but could increase the transfer of bacteria between meat pieces, whereas the use of rubber gloves could largely prevent the first and greatly reduce the second type of bacteria transfer.

Moving towards a latex-free environment: advice from experiences in US dentistry.

PubMed

Palenik, C J; Miller, C H

1999-12-01

Most dental practitioners now routinely wear gloves while treating patients. The most commonly used types of gloves contain latex. Latex is also present in other personal protective equipment, such as masks, eyewear and clinic gowns. Increased use of such items, unfortunately, has been linked to adverse skin and mucous membrane reactions. Latex proteins and chemicals associated with the material's production have been implicated. Exposure to such chemicals has also resulted in allergic responses in dental patients. There is a strong movement in the USA to limit exposure to latex in healthcare environments, including dentistry. The aim of this article is to describe past, present and future efforts to create low-latex or latex-free environments.

Survey of dermal protection in Washington State collision repair industry.

PubMed

Ceballos, Diana M; Fent, Kenneth W; Whittaker, Stephen G; Gaines, Linda G T; Thomasen, Jennifer M; Flack, Sheila L; Nylander-French, Leena A; Yost, Michael G; Reeb-Whitaker, Carolyn K

2011-09-01

Substantial exposure to isocyanates may occur during spray painting in autobody shops, yet information is lacking on the efficacy of the protective clothing used during spray painting. We investigated the personal and workplace factors associated with painters' dermal protection use during a large-scale exposure assessment study. Survey data indicated that 69% of painters always used gloves, with latex gloves (47%) and nitrile gloves (34%) used most frequently. Among latex glove users, 53% used thin latex (0.05-0.13 mm), 6% used medium latex (0.15-0.20 mm), and 12% used thick latex (> 0.20 mm). Among nitrile glove users, 27% used thin nitrile and 45% used medium nitrile. Sixty-three percent of painters always used coveralls, 44% preferring one particular brand. Although overspray presents an opportunity for dermal exposure to the neck and face, only 19% of painters protected these areas with personal protective equipment. Painters who always used coveralls were more likely to use gloves (odds ratio = 7.9, p = 0.061). Painters who reported ever having smoked cigarettes used gloves (p = 0.05) and coveralls (p = 0.04) more frequently. Painters who sprayed more than 34 clear coat jobs per month used coveralls most frequently (p = 0.038). Exact logistic regressions along with random sample calculations indicated that the survey results were independent of the shops. Because of the small sample size in this study, future research is warranted to corroborate these results. Studying the effectiveness of gloves and coveralls against polyurethane paints and understanding the underlying motivators and preferences for painters and business owners is needed for the development of best practices for the selection and use of dermal protection.

Protective gloves for use in high-risk patients: how much do they affect the dexterity of the surgeon?

PubMed Central

Phillips, A. M.; Birch, N. C.; Ribbans, W. J.

1997-01-01

Twenty-five orthopaedic surgeons underwent eight motor and sensory tests while using four different glove combinations and without gloves. As well as single and double latex, surgeons wore a simple Kevlar glove with latex inside and outside and then wore a Kevlar and Medak glove with latex inside and outside, as recommended by the manufacturers. The effect of learning with each sequence was neutralised by randomising the glove order. The time taken to complete each test was recorded and, where appropriate, error rates were noted. Simple sensory tests took progressively longer to perform so that using the thickest glove combination led to the completion times being doubled. Error rates increased significantly. Tests of stereognosis also took longer and use of the thickest glove combination caused these tests to take three times as long on average. Error rates again increased significantly. However, prolongation of motor tasks was less marked. We conclude that, armed with this quantitative analysis of sensitivity and dexterity impairment, surgeons can judge the relative difficulties that may be incurred as a result of wearing the gloves against the benefits that they offer in protection. PMID:9135240

An evidence-based approach to medication preparation for the surgical patient at risk for latex allergy: is it time to stop being stopper poppers?

PubMed

Heitz, James W; Bader, Stephen O

2010-09-01

The prevalence of latex allergy is increasing in surgical patient populations. Avoidance of exposure to the allergen is essential to minimizing perioperative complications in patients suspected to be at risk. Natural rubber latex has historically been ubiquitous in medical devices containing rubber. In 1998, the Food and Drug Administration (FDA) began to require the labeling of medical devices made from natural rubber latex; since that time substantial progress has been made in identifying latex-free alternatives. However, the rubber stoppers commonly found in pharmaceutical vial closures are exempt from FDA labeling requirements. Examination of the clinical and basic science literature regarding pharmaceutical vial closures supports limiting the rubber stopper to a single needle puncture as a safer practice, with the caveat that no strategy exists for the complete elimination of risk as long as stoppers made from natural rubber latex are used in pharmaceutical vials intended for human use. Copyright © 2010 Elsevier Inc. All rights reserved.

Occupational contact urticaria: lessons from the French National Network for Occupational Disease Vigilance and Prevention (RNV3P).

PubMed

Bensefa-Colas, L; Telle-Lamberton, M; Faye, S; Bourrain, J-L; Crépy, M-N; Lasfargues, G; Choudat, D; Momas, I

2015-12-01

Occupational contact urticaria (OCU) is an occupational contact dermatitis that can cause serious health consequences and disability at work. To describe OCU and its temporal trends by the main causal agents and activity sectors in a nationwide scheme in France. Using data from the French National Network for Occupational Disease Vigilance and Prevention (RNV3P), we described OCU reported during the period 2001-10 and analysed the temporal trends of OCU and OCU attributed to the most frequent agents over the study period. Trends analyses were supported by reporting odds ratios using a logistic regression model with reference to 2001, or with time as a continuous variable. During the study period, 251 cases of OCU were reported in RNV3P, half of which were due to natural rubber latex, in particular in the health and social work activity sector (HSW). The number of these cases declined significantly over the study period (19% per year), and particularly after 2006. Conversely, the other causes of OCU did not decrease. Using surveillance data from a French national network, this study has found that there was a significant decline in OCU due to natural rubber latex, particularly in the HSW, when powdered latex gloves were banned from French hospitals. Our results show the effectiveness of this preventive measure, and suggest that this practice should be extended to other sectors. © 2015 British Association of Dermatologists.

Latex sensitisation in healthcare workers in Singapore.

PubMed

Tang, M B Y; Leow, Y H; Ng, V; Koh, D; Goh, C L

2005-06-01

Epidemiological data on latex sensitisation among Asian healthcare workers is lacking. The aim of the study is to determine the rate of latex sensitisation in our healthcare workers. We recruited 313 healthcare workers, of which 46.6% were operating theatre staff and 53.4% were non-operating theatre staff. Seventy-one administrative staff served as controls. All participants answered a self-administered questionnaire relating to latex exposure and glove-related symptoms. Latex sensitisation was determined by skin prick testing to latex and latex-specific IgE detection. The prevalence of latex sensitisation among healthcare workers was 9.6%, with no difference between operating theatre and nonoperating theatre staff. Glove-related symptoms were reported in 13.7% of all healthcare workers, of which 22.9% were sensitised to latex. Only 26.7% of latex-sensitised healthcare workers had glove-related symptoms while the rest were asymptomatic. The most common symptoms were itch and hand eczema but the most important discriminating symptom was contact urticaria. Personal history of atopy was more common in sensitised healthcare workers (40.0%) compared to non-sensitised workers (31.8%). Only 1 out of 9 (11.2%) symptomatic latex-sensitised subjects had sought previous medical attention for the problem. Latex sensitisation among healthcare workers in Singapore should be considered a significant occupational health risk, as it is in the West. Increased screening and awareness of this problem is essential to identify those at risk.

75 FR 68394 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-05

... Woven and Knit impregnated with Flat Dipped Rubber/Plastic Gloves. SUMMARY: The U. S. Small Business... Flat Dipped Rubber/Plastic Gloves, under North American Industry Classification System (NAICS) code... Rule for Woven and Knit impregnated with Flat Dipped Rubber/Plastic Gloves under PSC 9999...

75 FR 52789 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-27

... for Woven and Knit impregnated with Flat Dipped Rubber/Plastic Gloves. SUMMARY: The U.S. Small... for woven and knit impregnated with flat dipped rubber/plastic gloves, under the North American... Dipped Rubber/Plastic Gloves manufacturers. If granted, the waiver would allow otherwise qualified small...

Micro-organisms in latex and natural rubber coagula of Hevea brasiliensis and their impact on rubber composition, structure and properties.

PubMed

Salomez, M; Subileau, M; Intapun, J; Bonfils, F; Sainte-Beuve, J; Vaysse, L; Dubreucq, E

2014-10-01

Natural rubber, produced by coagulation of the latex from the tree Hevea brasiliensis, is an important biopolymer used in many applications for its outstanding properties. Besides polyisoprene, latex is rich in many nonisoprene components such as carbohydrates, proteins and lipids and thereby constitutes a favourable medium for the development of micro-organisms. The fresh rubber coagula obtained by latex coagulation are not immediately processed, allowing the development of various microbial communities. The time period between tree tapping and coagula processing is called maturation, during which an evolution of the properties of the corresponding dry natural rubber occurs. This evolution is partly related to the activity of micro-organisms and to the modification of the biochemical composition. This review synthesizes the current knowledge on microbial populations in latex and natural rubber coagula of H. brasiliensis and the changes they induce on the biochemistry and technical properties of natural rubber during maturation. © 2014 The Society for Applied Microbiology.

The 14.6 kd rubber elongation factor (Hev b 1) and 24 kd (Hev b 3) rubber particle proteins are recognized by IgE from patients with spina bifida and latex allergy.

PubMed

Yeang, H Y; Cheong, K F; Sunderasan, E; Hamzah, S; Chew, N P; Hamid, S; Hamilton, R G; Cardosa, M J

1996-09-01

Two major water-insoluble proteins are located on the surface of rubber particles in Hevea brasiliensis latex. A 14.6 kd protein (Hev b 1), found mainly on large rubber particles (> 350 mm in diameter), and a 24 kd protein (Hev b 3), found mainly on small rubber particles (average diameter, 70 nm), are recognized by IgE from patients with spina bifida and latex allergy. Although Hev b 1 (also called the rubber elongation factor [REF]) has previously been reported as a major latex allergen, this conclusion has been disputed on the basis of results from other studies. The allergenicity of Hev b 1 is verified in this study by testing the recombinant protein generated from its gene. Because allergenicity is confined to patients with spina bifida and not observed in adults sensitive to latex, it is not a major latex allergen. The identification of Hev b 3 as another allergen originating from rubber particles is confirmed by immunogold labeling and electron microscopy. Observations with the monoclonal antibody USM/RC2 developed against Hev b 3 show that the protein has a tendency to fragment into several polypeptides of lower molecular weight (from 24 kd to about 5 kd) when stored at -20 degrees C. There is also indication of protein aggregation from the appearance of proteins with molecular weights greater than 24 kd. Fragmentation of Hev b 3 is induced immediately on he addition of latex B-serum, which is normally compartmentalized in the lutoids in fresh latex. In the preparation of ammoniated latex (used for the manufacture of latex products), the lutoids are ruptured, and the released B-serum reacts with Hev b 3 on the rubber particles to give rise to an array of low molecular weight polypeptides that are allergenic to patients with spina bifida.

Citizen's Petition to Food and Drug Administration to ban cornstarch powder on medical gloves: Maltese cross birefringence.

PubMed

Edlich, Richard F; Long, William B; Gubler, K Dean; Rodeheaver, George T; Thacker, John G; Borel, Lise; Chase, Margot E; Cross, Catherine L; Fisher, Allyson L; Lin, Kant Y; Cox, Mary J; Zura, Robert B

2009-02-01

During the last 25 years, scientific experimental and clinical studies have documented the dangers of cornstarch powder on examination and surgical gloves because the cornstarch promotes wound infection, causes serious peritoneal adhesions and granulomatous peritonitis, and is a well-documented vector of the latex allergy epidemic in the world. Realizing the dangers of cornstarch on examination and surgical gloves, Germany's regulations of personal protective equipment banned the use of surgical glove powder cornstarch in 1997. In 2000, the Purchasing and Supply agency for the United Kingdom ceased to purchase any gloves lubricated with cornstarch. Realizing the dangers of cornstarch-powdered gloves, many hospitals and clinics in the United States have banned the use of cornstarch-powdered examination and surgical gloves. Hospitals that have banned cornstarch in their examination and surgical gloves have noted a marked reduction in the latex allergy epidemic in their facilities. Realizing the dangers of cornstarch-powdered examination and surgical gloves, Dr Sheila A. Murphey, branch chief, Infection Control Devices Branch, Division of Anesthesiology, General Hospital, Infection Control, and Dental Devices Office of Device Evaluation, Center for Devices and Radiological Health of the Food and Drug Administration (FDA), recommended that a Citizen's Petition be filed to the FDA to ban cornstarch on surgical and examination gloves. The 12 authors of this report have attached the enclosed petition to the FDA to ban the use of cornstarch on all synthetic and latex examination and surgical gloves used in the United States.

PCR-Based Method for Detecting Viral Penetration of Medical Exam Gloves

PubMed Central

Broyles, John M.; O'Connell, Kevin P.; Korniewicz, Denise M.

2002-01-01

The test approved by the U.S. Food and Drug Administration for assessment of the barrier quality of medical exam gloves includes visual inspection and a water leak test. Neither method tests directly the ability of gloves to prevent penetration by microorganisms. Methods that use microorganisms (viruses and bacteria) to test gloves have been developed but require classical culturing of the organism to detect it. We have developed a PCR assay for bacteriophage φX174 that allows the rapid detection of penetration of gloves by this virus. The method is suitable for use with both latex and synthetic gloves. The presence of glove powder on either latex or synthetic gloves had no effect on the ability of the PCR assay to detect bacteriophage DNA. The assay is rapid, sensitive, and inexpensive; requires only small sample volumes; and can be automated. PMID:12149320

Exploiting epoxidized natural rubber latex (ENRL) as a starting raw material for latex-based products

NASA Astrophysics Data System (ADS)

Siti Nor Qamarina, M.; Fatimah Rubaizah, M. R.; Nurul Suhaira, A.; Norhanifah, M. Y.

2017-12-01

Epoxidized natural rubber latex (ENRL) is a chemically modified natural rubber latex produced from epoxidation process that involves usage of organic peracids. Conversion of the ENRL into dry rubber products has been known to exhibit many beneficial properties, however limited published works were found on diversifiying the ENRL latex-based products applications. In this preliminary work, different source of raw materials and neutralization systems were investigated. The objective was to explore possibilities in producing distinctive ENRL. Findings have demonstrated that different source of raw materials and neutralization systems influenced the typical ENRL specifications, stability behavior and particle size distribution. Morphological observations performed on these ENRL systems appeared to agree with the ENRL characteristics achieved. Since experimenting these two main factors resulted in encouraging ENRL findings, detailed work shall be further scrutinized to search for an optimum condition in producing marketable ENRL specifically for latex-based products applications.

EVALUATION OF GLOVEBOX GLOVES FOR EFFECTIVE PERMEATION CONTROL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinko, P.

A research and development task was undertaken to determine the permeabilities of hydrogen and dry air through different polymeric glove materials that are used to maintain the integrity of glovebox secondary containment. Fifteen different glove samples were obtained from four different manufacturers and samples cut from these gloves were tested. The gloves included baseline butyl rubber, Viton{reg_sign}, Dupont{reg_sign} Hypalon{reg_sign}, polyurethane, as well as composite gloves. The testing indicated that all of the vendor's butyl rubber gloves and the Jung Viton{reg_sign} gloves performed comparably in both gases.

Effects of wearing rubber gloves on activities of the forearm and shoulder muscles during different dishwashing stages

PubMed Central

Yoo, Won-Gyu

2015-01-01

[Purpose] The present study examined the effects of wearing rubber gloves on the activities of the forearm and shoulder muscles during two dishwashing stages. [Subjects] This study included 10 young females. [Methods] The participants performed two dishwashing stages (washing and rinsing) with and without rubber gloves. The activities of the wrist flexor and upper trapezius muscles were measured using wireless electromyography. [Results] During the washing stage, the activities of the wrist flexor and upper trapezius muscles were significantly greater without gloves than with gloves when performing the same tasks. However, during the rinsing stage, the activities of these muscles did not differ significantly according to the use of gloves. [Conclusion] Dishwashers should wear gloves during the washing stage to prevent wrist and shoulder pain. PMID:26311980

Permeation of hair dye ingredients, p-phenylenediamine and aminophenol isomers, through protective gloves.

PubMed

Lee, Hsiao-Shu; Lin, Yu-Wen

2009-04-01

Skin irritation and contact allergies are skin disorders common to hairdressers. The predominant oxidative hair dye components, such as p-phenylenediamine (PPD) and aminophenol isomers, can cause contact dermatitis. Use of protective gloves can prevent dermal contact with skin irritants. This study investigates the permeation behaviors of p-aminophenol (PAP), m-aminophenol (MAP), o-aminophenol (OAP) and PPD in single and mixed challenge solutions with disposable natural rubber latex (NRL) gloves, disposable polyvinylchloride (PVC) gloves and neoprene (NP) gloves. The challenge solutions were 4% PPD (w/v), 3% OAP (w/v), 2% PAP (w/v) and 2% MAP (w/v) in ethanol or 12% hydrogen peroxide solutions. The cocktail solutions of the four chemicals were also tested. An American Society for Testing and Materials type permeation cell, ethanol liquid collection and gas chromatography-flame ionization detection of samples taken from the collection medium every 10 min facilitated determination of breakthrough times (BTs), cumulative permeated masses and steady-state permeation rates (SSPRs). Experiments were 4 h long for the NRL and PVC gloves and 8 h for NP gloves. No chemicals tested broke through the NP gloves when exposed for 8 h. In the ethanol solution, PPD and OAP started breaking through the PVC gloves at 40 min. The SSPRs of PVC gloves were higher than those for NRL gloves in all challenge conditions for both single chemicals and mixtures. No tested chemicals in hydrogen peroxide solutions permeated the gloves during the 4-h tests. The chemical composition of the challenge solution was a main effecter of BTs and SSPRs for the NRL glove. For disposable PVC gloves, the main factors of BTs were molecular size [molar volume (MV)] and polarity (logK(ow)), and the primary factors of SSPRs were concentration, MV and logK(ow). In conclusion, disposable NRL gloves and disposable PVC gloves should not be used repeatedly for handling the hair dye products. Hydrogen peroxide did not accelerate chemical breakthrough. The compositions of the challenge solutions and physical and chemical properties (MV and logK(ow)) affected permeation behaviors for different gloves.

Detection and toxicity assessment of nitrosamines migration from latex gloves in the Chinese market.

PubMed

Feng, Di; Wang, Huiping; Cheng, Xuelian; Wang, Jiedong; Ning, Lifeng; Zhou, Qingfeng; Zhou, Yue; Yang, Quanli

2009-09-01

Nitrosamines are potent carcinogens and have been found in latex products. In 2007, twenty-seven natural latex gloves including sterile gloves, examination gloves and household use gloves were sampled from the Chinese market. This study monitored the migration of nitrosamines and nitrosatable substance from these gloves, and evaluated their mutagenicity using a Salmonella typhimurium mutation assay (Ames assay) with the strains TA98, TA97, TA100 and TA102 and by a micronucleus test (MN test) using ICR mice. In addition, the cytotoxicity of these compounds was determined by a MTT assay. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodibutylamine (NDBA) were all found in samples treated with artificial sweat for 4h at 37 degrees C, and total nitrosamines varied from 18.89 to 244.51microg/Kg. The nitrosamine mixture of NDMA, NDEA and NDBA was used in both the Ames assay and the MN test. The proportion of NDMA, NDEA and NDBA (1:10:20) was selected according to the proportion of nitrosamines migration from sample E05. In the Ames assay, the lowest dose (1.98 x 10(-3)microg per plate) produced a positive result in the TA98 strain, corresponding to nitrosamines migration from sample E05 of 0.016g (the total nitrosamines migration from glove E05 was 122.55 microg/kg). The TA100 strain responded positively at a dose of 4.96 x 10(-2)microg per plate, corresponding to nitrosamines migration from glove E05 of 0.040g. The MN test showed nitrosamine migration of 3.04 mg from 2066 pairs of sample E05 and could induce micronuclei in one mouse weighing 28g (average weight of one E05 glove was 6g). Extracts from gloves were found to be cytotoxic and there was a significant correlation between cytotoxicity (IC50) and the release level of nitrosamines. In conclusion, in view of the high content of nitrosamines in latex gloves and the potential toxicity of nitrosamines migration from these gloves, it is suggested that both an effective and feasible detection method and prescribed limits should be imposed.

[Powder-induced anaphylactic shock following use of powdered latex gloves during gynecological open laparotomy].

PubMed

Mizuno, Ju; In-nami, Hiroshi; Saegusa, Hiroaki; Kibayashi, Junichiro; Jimbo, Masanori; Kida, Kotaro; Ichiishi, Noriko

2006-06-01

A 42-year-old woman with hysteromyoma underwent total abdominal hysterectomy under general and epidural anesthesia. Three years before, she had undergone resection of lipoma on her left shoulder under local anesthesia uneventfully. She had no previous history of hypersensitivity. General anesthesia was induced by intravenous injection of fentanyl, propofol, and vecuronium followed by inhalation of nitrous oxide, oxygen, and sevoflurane. Lidocaine and fentanyl were injected through a lumbar epidural catheter. After the start of open laparotomy, there was a sudden onset of hypotension. Administrations of ephedrine and phenylephrine, and volume loading were ineffective. Moreover, she showed profound hypotension, tachycardia, oxygen desaturation, decreased endtidal carbon dioxide and increased airway pressure. She broke out in a sweat with flushing on her chest and upper extremities. Therefore, we interrupted the surgery, checked her arterial blood gas analysis, performed echocardiography, and inserted a pulmonary artery catheter. We made a diagnosis of anaphylactic shock and administered methylprednisolone, albumin, epinephrine, norepinephrine, and dopamine to treat the circulatory collapse. The gynecologists changed their surgical gloves from a powdered-latex type to a powder-free latex type, and the surgery was resumed. She responded well to appropriate emergent therapy and all vasopressor drugs were gradually decreased and eventually stopped. After the end of the surgery, she recovered completely from the signs and symptoms of shock. Later, we found a high level of plasma latex protein-specific IgE antibody and confirmed the events as anaphylactic shock due to latex. We assumed that the anaphylactic shock was powder-induced latex allergy following use of powdered latex gloves in this case. Latex allergy should be suspected if an anaphylactic reaction or shock accompanied by circulatory collapse, respiratory failure, and skin symptoms of unknown origin occurs during surgery. As women more often come into contact with household articles containing latex, we suspect that women are prone to developing sensitivity towards latex. We recommend that powder-free or latex-free surgical gloves should be available not only for patients with a high risk of developing latex allergy, but also for patients indicated for gynecological open laparotomy.

Glove material, reservoir formation, and dose affect glove permeation and subsequent skin penetration.

PubMed

Nielsen, Jesper Bo; Sørensen, Jens Ahm

2012-02-15

Protective gloves are used to reduce dermal exposure when managing chemical exposures at the work place. Different glove materials may offer different degrees of protection. The present study combined the traditional ASTM (American Society for Testing and Materials) model with the Franz diffusion cell to evaluate overall penetration through glove and skin as well as the deposition in the different reservoirs. Benzoic acid was applied on latex or nitrile gloves placed on top of human skin. The amounts of chemical were quantified in the glove material, between glove and skin, within the skin, and in the receptor chamber. Both glove materials reduce total penetration of benzoic acid, but nitrile gloves offer a significantly better protection than latex gloves. This difference was less pronounced at the higher of the two concentrations of benzoic acid applied. Thus, glove types that offer relevant protection at low concentrations does not necessarily give appropriate protection at high concentrations. Significant amounts of benzoic acid could be extracted from the glove materials after exposure. If a chemical is accumulated in the glove material, reuse of single-use gloves should be cautioned. The reuse of gloves is generally not to be recommended without effective decontamination. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of Reference Genes for Quantitative Real-Time PCR Analysis of the Gene Expression in Laticifers on the Basis of Latex Flow in Rubber Tree (Hevea brasiliensis Muell. Arg.)

PubMed Central

Chao, Jinquan; Yang, Shuguang; Chen, Yueyi; Tian, Wei-Min

2016-01-01

Latex exploitation-caused latex flow is effective in enhancing latex regeneration in laticifer cells of rubber tree. It should be suitable for screening appropriate reference gene for analysis of the expression of latex regeneration-related genes by quantitative real-time PCR (qRT-PCR). In the present study, the expression stability of 23 candidate reference genes was evaluated on the basis of latex flow by using geNorm and NormFinder algorithms. Ubiquitin-protein ligase 2a (UBC2a) and ubiquitin-protein ligase 2b (UBC2b) were the two most stable genes among the selected candidate references in rubber tree clones with differential duration of latex flow. The two genes were also high-ranked in previous reference gene screening across different tissues and experimental conditions. By contrast, the transcripts of latex regeneration-related genes fluctuated significantly during latex flow. The results suggest that screening reference gene during latex flow should be an efficient and effective clue for selection of reference genes in qRT-PCR. PMID:27524995

Lack of latex allergen contamination of solutions withdrawn from vials with natural rubber stoppers.

PubMed

Thomsen, D J; Burke, T G

2000-01-01

The effect on latex allergen contamination and microbial growth of a latex-allergy precaution technique for preparing injectable products was studied. The study consisted of three parts: (1) preparation of 20 samples from vials with latex-containing stoppers in accordance with conventional guidelines, (2) preparation of 20 samples in accordance with latex-allergy precaution guidelines, and (3) preparation of 5 latex-free samples and 1 latex-contaminated sample as negative and positive controls, respectively. The conventional method involved swabbing a vial top with an alcohol prep pad, puncturing the dry natural rubber stopper with an 18-gauge needle attached to a latex-free syringe, and withdrawing the contents of the vial into the syringe. The latex-allergy precaution preparation technique was similar, except that the stopper was removed before the vial contents were withdrawn. There was essentially no difference in latex allergen concentrations between the two drug preparation methods. None of the samples prepared with the standard method supported any microbial growth. One sample prepared with the latex-allergy precaution method grew bacteria. Removal of the dry rubber stopper from vials did not yield solutions with less latex allergen than solutions prepared according to conventional guidelines.

Large-scale collection of full-length cDNA and transcriptome analysis in Hevea brasiliensis

PubMed Central

Makita, Yuko; Ng, Kiaw Kiaw; Veera Singham, G.; Kawashima, Mika; Hirakawa, Hideki; Sato, Shusei

2017-01-01

Abstract Natural rubber has unique physical properties that cannot be replaced by products from other latex-producing plants or petrochemically produced synthetic rubbers. Rubber from Hevea brasiliensis is the main commercial source for this natural rubber that has a cis-polyisoprene configuration. For sustainable production of enough rubber to meet demand elucidation of the molecular mechanisms involved in the production of latex is vital. To this end, we firstly constructed rubber full-length cDNA libraries of RRIM 600 cultivar and sequenced around 20,000 clones by the Sanger method and over 15,000 contigs by Illumina sequencer. With these data, we updated around 5,500 gene structures and newly annotated around 9,500 transcription start sites. Second, to elucidate the rubber biosynthetic pathways and their transcriptional regulation, we carried out tissue- and cultivar-specific RNA-Seq analysis. By using our recently published genome sequence, we confirmed the expression patterns of the rubber biosynthetic genes. Our data suggest that the cytoplasmic mevalonate (MVA) pathway is the main route for isoprenoid biosynthesis in latex production. In addition to the well-studied polymerization factors, we suggest that rubber elongation factor 8 (REF8) is a candidate factor in cis-polyisoprene biosynthesis. We have also identified 39 transcription factors that may be key regulators in latex production. Expression profile analysis using two additional cultivars, RRIM 901 and PB 350, via an RNA-Seq approach revealed possible expression differences between a high latex-yielding cultivar and a disease-resistant cultivar. PMID:28431015

Insights into rubber biosynthesis from transcriptome analysis of Hevea brasiliensis latex.

PubMed

Chow, Keng-See; Wan, Kiew-Lian; Isa, Mohd Noor Mat; Bahari, Azlina; Tan, Siang-Hee; Harikrishna, K; Yeang, Hoong-Yeet

2007-01-01

Hevea brasiliensis is the most widely cultivated species for commercial production of natural rubber (cis-polyisoprene). In this study, 10,040 expressed sequence tags (ESTs) were generated from the latex of the rubber tree, which represents the cytoplasmic content of a single cell type, in order to analyse the latex transcription profile with emphasis on rubber biosynthesis-related genes. A total of 3,441 unique transcripts (UTs) were obtained after quality editing and assembly of EST sequences. Functional classification of UTs according to the Gene Ontology convention showed that 73.8% were related to genes of unknown function. Among highly expressed ESTs, a significant proportion encoded proteins related to rubber biosynthesis and stress or defence responses. Sequences encoding rubber particle membrane proteins (RPMPs) belonging to three protein families accounted for 12% of the ESTs. Characterization of these ESTs revealed nine RPMP variants (7.9-27 kDa) including the 14 kDa REF (rubber elongation factor) and 22 kDa SRPP (small rubber particle protein). The expression of multiple RPMP isoforms in latex was shown using antibodies against REF and SRPP. Both EST and quantitative reverse transcription-PCR (QRT-PCR) analyses demonstrated REF and SRPP to be the most abundant transcripts in latex. Besides rubber biosynthesis, comparative sequence analysis showed that the RPMPs are highly similar to sequences in the plant kingdom having stress-related functions. Implications of the RPMP function in cis-polyisoprene biosynthesis in the context of transcript abundance and differential gene expression are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berardinelli, S.P.; Rusczek, R.A.; Mickelsen, R.L.

The National Institute for Occupational Safety and Health (NIOSH), in cooperation with Monsanto Chemical Company, conducted an on-site evaluation of chemical protective clothing at Monsanto's Nitro, West Virginia plant. The Monsanto plant manufactures additives for the rubber industry including antioxidants, pre-vulcanization inhibitors, accelerators, etc. This survey evaluated six raw materials that have a potential for skin absorption: aniline, cyclohexylamine, diisorpropylamine, tertiary butylamine, morpholine and carbon disulfide. Five generic glove materials were tested against these chemicals; nitrile, neoprene, polyvinylchloride, natural latex and natural rubber. The NIOSH chemical permeation portable test system was used to generate breakthrough time data. The results weremore » compared to permeation data reported in the literature that were obtained by using the ASTM F739-85 test method. The test data demonstrated that aniline has too low a vapor pressure for reliable analysis on the portable direct reading detectors used. The chemical permeation test system, however provided comparable, reliable permeation data for the other tested chemicals. Monsanto has used this data to better select chemical protective clothing for its intended use.« less

Structural characterization of rubber from jackfruit and euphorbia as a model of natural rubber.

PubMed

Mekkriengkrai, Dararat; Ute, Koiichi; Swiezewska, Ewa; Chojnacki, Tadeusz; Tanaka, Yasuyuki; Sakdapipanich, Jitladda T

2004-01-01

A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

Jackfruit anaphylaxis in a latex allergic patient.

PubMed

Wongrakpanich, Supakanya; Klaewsongkram, Jettanong; Chantaphakul, Hiroshi; Ruxrungtham, Kiat

2015-03-01

Several fruits have been reported to crossreact with latex antigen in latex allergy patients but little is known regarding tropical fruits in particular. Here we report the case of a 34-year old nurse who developed anaphylaxis following the ingestion of dried jackfruit (Artocarpus heterophyllus). The patient had a history of chronic eczema on both hands resulting from a regular wear of latex gloves. She and her family also had a history of atopy (allergic rhinitis and/or atopic dermatitis). The results of skin prick tests were positive for jackfruit, latex glove, kiwi and papaya, but the test was negative for banana. While we are reporting the first case of jackfruit anaphylaxis, further research needs to be conducted to identify the mechanisms underlying it. In particular, in-vitro studies need to be designed to understand if the anaphylaxis we describe is due to a cross reactivity between latex and jackfruit or a coincidence of allergy to these 2 antigens.

Indirect latex glove contamination and its inhibitory effect on vinyl polysiloxane polymerization.

PubMed

Kimoto, Katsuhiko; Tanaka, Kinya; Toyoda, Minoru; Ochiai, Kent T

2005-05-01

The inhibitory effect of indirect latex contamination on the polymerization of vinyl polysiloxane (VPS) impression material has been previously reported. However, the transfer of specific elements that cause inhibition has not been confirmed, nor has the removal of such contaminants been reported. This study examined the surfaces of materials commonly used in restorative procedures that were contaminated by indirect latex glove contact and then evaluated for inhibition of polymerization of VPS. The effect of selected cleansing procedures was then studied. Four experimental groups (n = 8) were prepared: (1) clean vinyl gloves (control), (2) clean gingival retraction cords (control), (3) contaminated vinyl gloves, and (4) contaminated gingival retraction cord. Microscopic evaluation of the appearance and the characterization of surface particulate contamination were performed for each. Three cleansing protocols were then evaluated for efficacy in cleaning vinyl glove surfaces contaminated by latex contact (n = 10): (1) brushing with water, (2) brushing with soap/rinsing with water, (3) cleansing with rubbing alcohol. The subsequent degree of VPS polymerization inhibition was evaluated subjectively. A chi-square test was used for data analysis (alpha=.05). Particulate sulfur elements and sulfur-chloride compounds were present on the contaminated substrates. None of the 3 cleansing procedures eliminated polymerization inhibition (P =.33). Residual elemental sulfur remained on all tested surfaces. Particulate sulfur and sulfur-chloride compounds were identified as the particulate contamination that resulted in polymerization inhibition of the tested VPS dental impression material. Removal of these contaminants from the tested vinyl gloves and gingival retraction cord was not possible with the 3 cleansing protocols tested in this study.

Feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers.

PubMed

Tang, S N; Fakhru'l-Razi, A; Hassan, M A; Karim, M I

1999-01-01

Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.

Health Issues and Treatments

MedlinePlus

... infants, school age, and adolescent/young adult. Latex (Natural Rubber) Allergy Many people with spina bifida are allergic to products that contain latex, or natural rubber. This means they should not use items ...

Thermal and mechanical properties of gamma-irradiated prevulcanized natural rubber latex/low nitrosamines latex blends

NASA Astrophysics Data System (ADS)

Ibrahim, Pairu; Daik, Rusli; Wan Zin, Wan Manshol

2016-12-01

Thermal and mechanical properties of blended radiation prevulcanized natural rubber latex (RVNRL) and low nitrosamines latex (LNL) were studied. RVNRL was blended with LNL at various composition ratios. From the tensile test, it was found that the optimum tensile value was attained at a total blending ratio of 70% RVNRL and 30% LNL. Latex blending with optimum tensile strength was then subjected to gamma irradiation at various doses with the presence and absence of methyl methacrylate (MMA) at 10 pphr. It was found that the gamma irradiation of latex blend with the presence of MMA could help increase further the tensile value. Composition of blending at a specific ratio and gamma irradiation at a specific dose has led to a significant improvement in the mechanical properties of the latex blend. The formation of grafting in the latex blend was characterized by Fourier transform infrared spectra (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy confirmed that MMA could be grafted onto blended latex effectively under appropriate irradiation conditions. Two new peaks at 1731 and 1149 cm-1 were observed after irradiation, indicating the presence of an ester group from poly(methyl methacrylate) (PMMA), which was grafted onto rubber chains. This finding was proved by the presence of new Tg in DSC analysis. The increase in new Tg indicates the movement of grafting chains, which are tightly bound onto rubber chains.

HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

PubMed

Liu, Shujin; Lan, Jixian; Zhou, Binhui; Qin, Yunxia; Zhou, Yihua; Xiao, Xiaohu; Yang, Jianghua; Gou, Jiqing; Qi, Jiyan; Huang, Yacheng; Tang, Chaorong

2015-04-01

In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Large-scale collection of full-length cDNA and transcriptome analysis in Hevea brasiliensis.

PubMed

Makita, Yuko; Ng, Kiaw Kiaw; Veera Singham, G; Kawashima, Mika; Hirakawa, Hideki; Sato, Shusei; Othman, Ahmad Sofiman; Matsui, Minami

2017-04-01

Natural rubber has unique physical properties that cannot be replaced by products from other latex-producing plants or petrochemically produced synthetic rubbers. Rubber from Hevea brasiliensis is the main commercial source for this natural rubber that has a cis-polyisoprene configuration. For sustainable production of enough rubber to meet demand elucidation of the molecular mechanisms involved in the production of latex is vital. To this end, we firstly constructed rubber full-length cDNA libraries of RRIM 600 cultivar and sequenced around 20,000 clones by the Sanger method and over 15,000 contigs by Illumina sequencer. With these data, we updated around 5,500 gene structures and newly annotated around 9,500 transcription start sites. Second, to elucidate the rubber biosynthetic pathways and their transcriptional regulation, we carried out tissue- and cultivar-specific RNA-Seq analysis. By using our recently published genome sequence, we confirmed the expression patterns of the rubber biosynthetic genes. Our data suggest that the cytoplasmic mevalonate (MVA) pathway is the main route for isoprenoid biosynthesis in latex production. In addition to the well-studied polymerization factors, we suggest that rubber elongation factor 8 (REF8) is a candidate factor in cis-polyisoprene biosynthesis. We have also identified 39 transcription factors that may be key regulators in latex production. Expression profile analysis using two additional cultivars, RRIM 901 and PB 350, via an RNA-Seq approach revealed possible expression differences between a high latex-yielding cultivar and a disease-resistant cultivar. © The Author 2017. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones.

PubMed

Tong, Zheng; Wang, Dan; Sun, Yong; Yang, Qian; Meng, Xueru; Wang, Limin; Feng, Weiqiang; Li, Ling; Wurtele, Eve Syrkin; Wang, Xuchu

2017-05-02

Rubber elongation factor (REF) and small rubber particle protein (SRPP) are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF 138,175,258 and SRPP 117,204,243 , were characterized from Hevea brasiliensis Reyan (RY) 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF 258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE), each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF 175 or REF 258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

A novel arctigenin-containing latex glove prevents latex allergy by inhibiting type I/IV allergic reactions.

PubMed

Wang, Yong-Xin; Xue, Dan-Ting; Liu, Meng; Zhou, Zheng-Min; Shang, Jing

2016-03-01

The present study aimed at developing a natural compound with anti-allergic effect and stability under latex glove manufacturing conditions and investigating whether its anti-allergic effect is maintained after its addition into the latex. The effects of nine natural compounds on growth of the RBL-2H3 cells and mouse primary spleen lymphocytes were determined using MTT assay. The compounds included glycyrrhizin, osthole, tetrandrine, tea polyphenol, catechin, arctigenin, oleanolic acid, baicalin and oxymatrine. An ELISA assay was used for the in vitro anti-type I/IV allergy screening; in this process β-hexosaminidase, histamine, and IL-4 released from RBL-2H3 cell lines and IFN-γ and IL-2 released from mouse primary spleen lymphocytes were taken as screening indices. The physical stability of eight natural compounds and the dissolubility of arctigenin, selected based on the in vitro pharnacodynamaic screening and the stability evaluation, were detected by HPLC. The in vivo pharmacodynamic confirmation of arctigenin and final latex product was evaluated with a passive cutaneous anaphylaxis (PCA) model and an allergen-specific skin response model. Nine natural compounds showed minor growth inhibition on RBL-2H3 cells and mouse primary spleen lymphocytes. Baicalin and arctigenin had the best anti-type I and IV allergic effects among the natural compounds based on the in vitro pharmacodynamic screening. Arctigenin and catechin had the best physical stability under different manufacturing conditions. Arctigenin was the selected for further evaluation and proven to have anti-type I and IV allergic effects in vivo in a dose-dependent manner. The final product of the arctigenin-containing latex glove had anti-type I and IV allergic effects in vivo which were mainly attributed to arctigenin as proved from the dissolubility results. Arctigenin showed anti-type I and IV allergic effects in vitro and in vivo, with a good stability under latex glove manufacturing conditions, and a persistent anti-allergic effect after being added into the latex to prevent latex allergy. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Retained portion of latex glove during femoral nailing. Case report.

PubMed

Sadat-Ali, M; Marwah, S; al-Habdan, I

1996-11-01

A case of retained glove during Kuntscher intramedullary nailing is described. An abscess around the glove could have lead to osteomyelitis. One need to be cautious feeling the top end of the nail while femoral nailing to avoid such a complication.

Mechanical and biological comparison of latex and silicone rubber bands.

PubMed

Hwang, Chung-Ju; Cha, Jung-Yul

2003-10-01

Latex rubber bands are routinely used to supply orthodontic force. However, because the incidence of allergic reactions to latex is rising, the use of nonlatex alternatives is increasing, and assessing the mechanical properties of the replacement products is becoming more important. The purposes of this study were to compare the mechanical properties of latex and silicone orthodontic rubber bands through static testing under dry and wet conditions, and to compare their biologic (cytotoxic) properties. Three brands of latex and 1 brand of silicone rubber bands were tested. When extended to 300% of the lumen diameter, the silicone group had an initial force equal to 83% of the product specifications; this was the lowest of the 4 groups. All 4 brands showed notable amounts of force degradation at the 300% extension when subjected to saliva immersion; this approximated a 30% force decay over 2 days. The latex bands all followed a similar pattern of force degradation, whereas the silicone bands showed a greater increase in force decay as the extension length increased. The silicone bands were less cytotoxic than 2 of the 3 types of latex. Although the silicone bands showed the least discrepancy of force degradation between air and saliva conditions, the amount of the force decay was the greatest. Therefore, great improvements in the physical properties of the silicone band are required before they can be considered an acceptable replacement for latex.

Norovirus Transmission between Hands, Gloves, Utensils, and Fresh Produce during Simulated Food Handling

PubMed Central

Aho, E.; Mikkelä, A.; Ranta, J.; Tuominen, P.; Rättö, M.; Maunula, L.

2014-01-01

Human noroviruses (HuNoVs), a leading cause of food-borne gastroenteritis worldwide, are easily transferred via ready-to-eat (RTE) foods, often prepared by infected food handlers. In this study, the transmission of HuNoV and murine norovirus (MuNoV) from virus-contaminated hands to latex gloves during gloving, as well as from virus-contaminated donor surfaces to recipient surfaces after simulated preparation of cucumber sandwiches, was inspected. Virus transfer was investigated by swabbing with polyester swabs, followed by nucleic acid extraction from the swabs with a commercial kit and quantitative reverse transcription-PCR. During gloving, transfer of MuNoV dried on the hand was observed 10/12 times. HuNoV, dried on latex gloves, was disseminated to clean pairs of gloves 10/12 times, whereas HuNoV without drying was disseminated 11/12 times. In the sandwich-preparing simulation, both viruses were transferred repeatedly to the first recipient surface (left hand, cucumber, and knife) during the preparation. Both MuNoV and HuNoV were transferred more efficiently from latex gloves to cucumbers (1.2% ± 0.6% and 1.5% ± 1.9%) than vice versa (0.7% ± 0.5% and 0.5% ± 0.4%). We estimated that transfer of at least one infective HuNoV from contaminated hands to the sandwich prepared was likely to occur if the hands of the food handler contained 3 log10 or more HuNoVs before gloving. Virus-contaminated gloves were estimated to transfer HuNoV to the food servings more efficiently than a single contaminated cucumber during handling. Our results indicate that virus-free food ingredients and good hand hygiene are needed to prevent HuNoV contamination of RTE foods. PMID:24951789

Characterization of associated proteins and phospholipids in natural rubber latex.

PubMed

Sansatsadeekul, Jitlada; Sakdapipanich, Jitladda; Rojruthai, Porntip

2011-06-01

Non-rubber components present in natural rubber (NR) latex, such as proteins and phospholipids, are presumed to be distributed in the serum fraction as well as surrounding the rubber particle surface. The phospholipid-protein layers covering the rubber particle surface are especially interesting due to their ability to enhance the colloidal stability of NR latex. In this study, we have characterized the components surrounding the NR particle surface and investigated their role in the colloidal stability of NR particles. Proteins from the cream fraction were proteolytically removed from the NR latex and compare to those from the serum fractions using SDS-polyacrylamide gel electrophoresis revealing that both fractions contained similar proteins in certain molecular weights such as 14.5, 25 and 27 kDa. Phospholipids removed from latex by treatment with NaOH were analyzed using (1)H-NMR spectroscopy and several major signals were assignable to -(CH(2))(n)-, -CH(2)OP, -CH(2)OC═O and -OCH(2)CH(2)NH-. These signals are important evidence that indicates phospholipids associate with the rubber chain. The colloidal behavior of rubber lattices before and after removal of protein-lipid membrane was evaluated by zeta potential analysis and scanning electron microscope (SEM). The lowest zeta potential value of NR particles was observed at pH 10, consequently leading to the highest stability of rubber particles. Additionally, SEM micrographs clearly displayed a gray ring near the particle surface corresponding to the protein-lipid membrane layer. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Method for forming a glove attachment

NASA Technical Reports Server (NTRS)

Dawn, Frederic S. (Inventor); Guy, Walter W. (Inventor); Kosmo, Joseph (Inventor); Drennan, Arthur P. (Inventor); Tschirch, Richard P. (Inventor)

1995-01-01

An attachment principally for the palm of an astronaut glove to enhance the gripping area of the palm without detracting from the flexibility and utility of the glove is presented. The attachment is a composite construction formed from a layer of silicone rubber having an outer surface with a friction configuration and another layer of silicone rubber in which a Nomex Aramid mesh fabric is embedded prior to curing. The method of construction involves the use of a mold with a friction configuration surface. A first layer of silicone rubber or sealant is disposed in the mold and allowed to set for an hour. A second layer of silicone rubber or sealant is layered over the first layer and leveled. A Nomex Aramid mesh fabric is embedded into the second layer and the composite is permitted to cure. When cured, a configured area of the composite construction is glued or stitched to the palm area of the glove.

Effect of urea deproteinization on catalytic hydrogenation of natural rubber latex

NASA Astrophysics Data System (ADS)

Cifriadi, A.; Chalid, M.; Puspitasari, S.

2017-07-01

Natural rubber is unsaturated biopolymer which has low resistance to heat, oxygen, and ozone. Chemical modification of natural rubber by catalytic hydrogenation can improve its oxidative property. In this study, the catalytic hydrogenation of natural rubber was investigated in latex phase after reduction of protein content with urea. Hydrogenation of deproteinized natural rubber latex was performed by using diimide which generated insitu from hydrazine hydrate/hydrogen peroxide and catalyst (boric acid, cupric sulfate and cupric acetate) at 70°C for 5 h. The hydrogenation system was stabilized with sodium dodecyl sulphate. The hydrogenation of deproteinized natural rubber (HDPNR) was confirmed by FTIR analysis. The result indicated that cupric sulphate was extremely active catalyst which was showed by the elimination of C=C transmittance bands at 1660 cm-1 on HDPNR spectra and highest degree of hydrogenation. Furthermore, urea deproteinization increased possibility of side reactions during catalytic hydrogenation as seen on the reduction of gel content compared to undeproteinized natural rubber.

Enhancement of MCF Rubber Utilizing Electric and Magnetic Fields, and Clarification of Electrolytic Polymerization

PubMed Central

Shimada, Kunio

2017-01-01

Many sensors require mechanical durability to resist immense or impulsive pressure and large elasticity, so that they can be installed in or assimilated into the outer layer of artificial skin on robots. Given these demanding requirements, we adopted natural rubber (NR-latex) and developed a new method (NM) for curing NR-latex by the application of a magnetic field under electrolytic polymerization. The aim of the present work is to clarify the new manufacturing process for NR-latex embedded with magnetic compound fluid (MCF) as a conductive filler, and the contribution of the optimization of the new process for sensor. We first clarify the effect of the magnetic field on the enhancement of the NR-latex MCF rubber created by the alignment of magnetic clusters of MCF. Next, SEM, XRD, Raman spectroscopy, and XPS are used for morphological and microscopic observation of the electrolytically polymerized MCF rubber, and a chemical approach measuring pH and ORP of the MCF rubber liquid was used to investigate the process of electrolytic polymerization with a physical mode. We elucidate why the MCF rubber produced by the NM is enhanced with high sensitivity and long-term stability. This process of producing MCF rubber by the NM is closely related to the development of a highly sensitive sensor. PMID:28375182

Occupational skin disease among Australian healthcare workers: a retrospective analysis from an occupational dermatology clinic, 1993-2014.

PubMed

Higgins, Claire L; Palmer, Amanda M; Cahill, Jennifer L; Nixon, Rosemary L

2016-10-01

Healthcare workers (HCWs) are at risk of developing occupational skin disease (OSD). To ascertain the causes of OSD in Australian HCWs in a tertiary referral clinic. A retrospective review was performed of patients assessed at the Occupational Dermatology Clinic in Melbourne from 1993 to 2014. Of 685 HCWs assessed in the clinic over a period of 22 years, 555 (81.0%) were diagnosed with OSD. The most common diagnosis was irritant contact dermatitis (ICD) (79.1%), followed by allergic contact dermatitis (ACD) (49.7%). Natural rubber latex allergy was also relatively frequent (13.0%). The major substances causing ACD were rubber glove chemicals (thiuram mix and tetraethylthiuram disulfide), preservatives (formaldehyde, formaldehyde releasers, and isothiazolinones), excipients in hand cleansers, which are hard-to-avoid weak allergens, and antiseptics. ACD caused by commercial hand cleansers occurred more frequently than ACD caused by alcohol-based hand rubs (ABHRs). Occupational ICD was mostly caused by water/wet work and hand cleansers, and environmental irritants such as heat and sweating. Understanding the causes of OSD in HCWs is important in order to develop strategies for prevention. We suggest that skin care advice should be incorporated into hand hygiene education. The use of ABHRs should be encouraged, weak allergens in skin cleansers should be substituted, and accelerator-free gloves should be recommended for HCWs with OSD. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Towards understanding the mechanisms and the kinetics of nanoparticle penetration through protective gloves

NASA Astrophysics Data System (ADS)

Vinches, L.; Peyrot, C.; Lemarchand, L.; Boutrigue, N.; Zemzem, M.; Wilkinson, K. J.; Hallé, S.; Tufenkji, N.

2015-05-01

Parallel to the increased use of engineered nanoparticles (ENP) in the formulation of commercial products or in medicine, numerous health & safety agencies have recommended the application of the precautionary principle to handle ENP; namely, the recommendation to use protective gloves against chemicals. However, recent studies reveal the penetration of titanium dioxide nanoparticles through nitrile rubber protective gloves in conditions simulating occupational use. This project is designed to understand the links between the penetration of gold nanoparticles (nAu) through nitrile rubber protective gloves and the mechanical and physical behaviour of the elastomer material subjected to conditions simulating occupational use (i.e., mechanical deformations (MD) and sweat). Preliminary analyses show that nAu suspensions penetrate selected glove materials after exposure to prolonged (3 hours) dynamic deformations. Significant morphological changes are observed on the outer surface of the glove sample; namely, the number and the surface of the micropores on the surface increase. Moreover, nitrile rubber protective gloves are also shown to be sensitive to the action of nAu suspension and to the action of the saline solution used to simulate sweat (swelling).

Profiling Ethylene-Responsive Genes Expressed in the Latex of the Mature Virgin Rubber Trees Using cDNA Microarray

PubMed Central

Nie, Zhiyi; Kang, Guijuan; Duan, Cuifang; Li, Yu; Dai, Longjun; Zeng, Rizhong

2016-01-01

Ethylene is commonly used as a latex stimulant of Hevea brasiliensis by application of ethephon (chloro-2-ethylphosphonic acid); however, the molecular mechanism by which ethylene increases latex production is not clear. To better understand the effects of ethylene stimulation on the laticiferous cells of rubber trees, a latex expressed sequence tag (EST)-based complementary DNA microarray containing 2,973 unique genes (probes) was first developed and used to analyze the gene expression changes in the latex of the mature virgin rubber trees after ethephon treatment at three different time-points: 8, 24 and 48 h. Transcript levels of 163 genes were significantly altered with fold-change values ≥ 2 or ≤ –2 (q-value < 0.05) in ethephon-treated rubber trees compared with control trees. Of the 163 genes, 92 were up-regulated and 71 down-regulated. The microarray results were further confirmed using real-time quantitative reverse transcript-PCR for 20 selected genes. The 163 ethylene-responsive genes were involved in several biological processes including organic substance metabolism, cellular metabolism, primary metabolism, biosynthetic process, cellular response to stimulus and stress. The presented data suggest that the laticifer water circulation, production and scavenging of reactive oxygen species, sugar metabolism, and assembly and depolymerization of the latex actin cytoskeleton might play important roles in ethylene-induced increase of latex production. The results may provide useful insights into understanding the molecular mechanism underlying the effect of ethylene on latex metabolism of H. brasiliensis. PMID:26985821

Preparation of vinyl acetate grafted natural rubber by irradiation method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porntrairat, A.; Pattamaprom, C.

Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content weremore » measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.« less

Respiratory and dermal symptoms in Thai nurses using latex products.

PubMed

Supapvanich, C; Povey, A C; de Vocht, F

2013-09-01

Despite known health risks related to the use of powdered latex gloves (PLGs), they are still widely used in hospitals in developing countries due to the high cost of alternatives. To determine the prevalence of dermal and respiratory symptoms associated with latex glove use in nurses in Thailand and evaluate the influence of previously reported occupational risk factors in this population. A cross-sectional study in female nurses working in three Thai hospitals. Participants completed a questionnaire on demographics, occupational and personal history, use of latex products at work and dermal and respiratory symptoms attributed to occupational use of latex gloves. Of 899 nurses, 18% reported health effects attributed to the use of latex products. After adjustment for confounding, occupational risk factors associated with increased reporting of dermal symptoms included wearing more than 15 pairs of PLG per day (odds ratio (OR): 2.10, 95% confidence interval (CI): [1.32-3.34]), using chlorhexidine (OR: 2.07, 95% CI: [1.22-3.52]) and being an operating theatre nurse (OR: 2.46, 95% CI: [1.47-4.12]). Being a labour ward nurse (OR: 3.52, 95% CI: [1.26-9.85]) was the only factor associated with increased reporting of respiratory symptoms. Continuing use of PLGs in Thai nurses is associated with increased prevalence of dermal symptoms compared with data from developed countries. Measures to reduce such health effects are well established and should be considered. Additionally, replacement of chlorhexidine with an alternative detergent seems advisable.

Preparation and application of nanocrystalline cellulose derived from sugarcane waste as filler modified alkanolamide on crosslink of natural rubber latex film

NASA Astrophysics Data System (ADS)

Harahap, Hamidah; Hayat, Nuim; Lubis, Marfuah

2017-07-01

Sugarcane waste is abundant sources of cellulose and it has potential to reutilize. Cellulose from sugarcane waste can be derived into nanocystalline cellulose (NCC) from crystalline region. The NCC as a filler has capability to reinforce natural rubber latex product. The crosslink in vulcanized natural rubber latex film influences several properties of product. In this work, we extracted NCC from sugarcane waste then added into natural rubber latex as filler modified alkanolamide (ALK) and also studied the crosslink of natural rubber latex films. NCC were produced from sugarcane waste by hydrolysis process with sulfuric acid 45%. The obtained NCC was characterized by using x-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infra red (FTIR). NCC was modified by alkanolamide and dispersed in water with filler concentration of 10%. Then the dispersion were added into latex system followed by pre-vulcanization at 70 °C. The films were prepared by coagulant dipping method and dried at 100 °C and 120 °C for 20 minutes. Characterization of NCC from sugarcane waste by using FTIR was done, it clearly showed the functional groups of cellulose. TEM showed the obtained NCC were rod-shaped with about 40-160 nm in diameter and several hundred nm in length, and XRD showed that the degree of crystalinity of NCC from sugarcane waste is 92.33%. The crosslink of natural rubber films were studied by measure the crosslink density for different filler loading by using swelling measurement with toluene solution. The result show that the crosslink density increased in line with amount of filler which added into the system, and also the crosslink density that obtained from vulcanization at 120 °C were higher than 100 °C.

Irradiation grafting of natural rubber latex with maleic anhydride and its compatibilization of poly(lactic acid)/natural rubber blends

NASA Astrophysics Data System (ADS)

Pongsathit, Siriwan; Pattamaprom, Cattaleeya

2018-03-01

Maleic anhydride (MA) is an interesting monomer to be grafted onto natural rubber(NR) due to its potential as a compatibilizer of hydrophobic rubbers and polymers with higher polarity. So far, radiation grafting of MA onto NR in latex state has not been reported. In this study, the grafting of NR with MA in latex state was investigated by exposing the latex to cobalt-60 gamma irradiation at a fixed MA content of 9% and a varied absorbed doses from 2 to 10 kGy. The FTIR spectrometer, 1H NMR spectrometer and gel content analysis have confirmed successful grafting of MA onto NR after irradiation. The grafted NRs were then used to increase the compatibility and the impact property of PLA/NR blends. It was found that the highest impact strength of the blends was achieved when the grafting was carried out at the absorbed dose of 4 kGy.

Effects of sulfur-based hemostatic agents and gingival retraction cords handled with latex gloves on the polymerization of polyvinyl siloxane impression materials

PubMed Central

MACHADO, Carlos Eduardo Palhares; GUEDES, Carlos Gramani

2011-01-01

Objectives This study investigated the possible interactions between three addition silicone materials (Express®, Aquasil Ultra® and Adsil®), three hemostatic agents (ferric sulfate, StatGel FS®; aluminum sulfate, GelCord®; and aluminum chloride, Hemostop®) and gingival retraction cords previously handled with latex gloves to determine whether direct contact with medicaments or indirect contamination by latex in conditions similar to those found in clinical practice inhibit or affect the setting of the impression materials. Material and Methods A portable device for the simultaneous test of several specimens was specifically developed for this study. Polymerization inhibition was analyzed by examination of the impressions and the molded surface. Ten trials were performed for each addition silicone material used in the study, at a total of 240 study samples. Results All the samples tested (N=240) were nonreactive regardless of the type of combination used. Conclusions Aluminum sulfate, ferric sulfate and aluminum chloride hemostatic solutions did not show any inhibitory potential on the addition silicone samples under study, and there were no changes in polymerization as a result of contact between addition silicone and retraction cords handled with latex gloves. PMID:22230998

Effects of sulfur-based hemostatic agents and gingival retraction cords handled with latex gloves on the polymerization of polyvinyl siloxane impression materials.

PubMed

Machado, Carlos Eduardo Palhares; Guedes, Carlos Gramani

2011-01-01

This study investigated the possible interactions between three addition silicone materials (Express®, Aquasil Ultra® and Adsil®), three hemostatic agents (ferric sulfate, StatGel FS®; aluminum sulfate, GelCord®; and aluminum chloride, Hemostop®) and gingival retraction cords previously handled with latex gloves to determine whether direct contact with medicaments or indirect contamination by latex in conditions similar to those found in clinical practice inhibit or affect the setting of the impression materials. A portable device for the simultaneous test of several specimens was specifically developed for this study. Polymerization inhibition was analyzed by examination of the impressions and the molded surface. Ten trials were performed for each addition silicone material used in the study, at a total of 240 study samples. All the samples tested (N=240) were nonreactive regardless of the type of combination used. Aluminum sulfate, ferric sulfate and aluminum chloride hemostatic solutions did not show any inhibitory potential on the addition silicone samples under study, and there were no changes in polymerization as a result of contact between addition silicone and retraction cords handled with latex gloves.

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

NASA Astrophysics Data System (ADS)

Karim, Ahmad Fikri Abdul; Ismail, Hanafi; Ariff, Zulkifli Mohamad

2015-07-01

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM).

Occupational allergic contact dermatitis from epoxy resin in a golf club repairman.

PubMed

Isaksson, Marléne; Möller, Halvor; Pontén, Ann

2008-01-01

A golfer presented with facial and hand eczema. He had exacerbations of his hand eczema prior to golf tournaments. Being an authorized golf club repairman, he had been working with a two-part glue containing an epoxy resin (ER) based on diglycidyl ether of bisphenol A (DGEBA) and the hardener diethylenetriamine (DETA) for approximately 4 years before he developed any skin problems. He was patch-tested with the standard, which contains an ER based on DGEBA (DGEBA-R), epoxy (containing DETA), and rubber glove series and had positive reactions to DGEBA-R only. Other work materials (a latex glove, a golf glove made of leather, and part of the handle of his own golf club "as is" and in a methyl tert-butyl ether extract) were tested, with negative results. Allergic contact dermatitis from ER affects the skin by direct contact; the dermatitis is usually localized to the hands and forearms. If the face and eyelids are involved, the dermatitis may be due to exposure to airborne hardeners or reactive diluents, exposure to airborne dust from residual monomers, or ectopic allergic reactions. Our repairman had sandpapered an old glued surface, which may have led to possible airborne dust formation, thus explaining the facial eczema. Therefore, a worker with contact allergy to ER may continue working provided the skin is protected from contamination.

Allergens in indoor air: environmental assessment and health effects.

PubMed

Carrer, P; Maroni, M; Alcini, D; Cavallo, D

2001-04-10

It has been suggested that the increase in morbidity and mortality for asthma and allergies, may also be due to an increase in exposure to allergens in the modern indoor environment. Indoor allergen exposure is recognised as the most important risk factor for asthma in children. House dust mites, pets, insects, plants, moulds and chemical agents in the indoor environment are important causes of allergic diseases. House dust mites and their debris and excrements that contain the allergens are normally found in the home in beds, mattresses, pillows, carpets and furniture stuffing, but they have also been found in office environments. Domestic animals such as cats, dogs, birds and rodents may cause allergic asthma and rhinoconjunctivitis. The exposure usually occurs in homes, but also in schools and kindergartens where domestic animals are kept as pets or for education; moreover, cat and dog owners can bring allergens to public areas in their clothes. Allergy to natural rubber latex has become an important occupational health concern in recent years, particularly among healthcare workers; when powdered gloves are worn or changed, latex particles get into the air and workers are exposed to latex aerosolised antigens. To assess the environmental risk to allergen exposure or to verify if there is a causal relationship between the immunologic findings in a patient and his/her environmental exposure, sampling from the suspected environment may be necessary.

Protein influences on guayule and Hevea natural rubber sol and gel

USDA-ARS?s Scientific Manuscript database

Guayule (Parthenium argentatum) is under cultivation in the southwestern United States as an alternative source of natural rubber free from proteins that cause Type I latex allergies. However, since guayule lacks the protein-polymer interactions present in Hevea latex, its physical and chemical prop...

Over-expression of 3-hydroxy-3- methylglutaryl-coenzyme A reductase 1 (hmgr1) gene under super-promoter for enhanced latex biosynthesis in rubber tree (Hevea brasiliensis Muell. Arg.).

PubMed

Jayashree, R; Nazeem, P A; Rekha, K; Sreelatha, S; Thulaseedharan, A; Krishnakumar, R; Kala, R G; Vineetha, M; Leda, P; Jinu, U; Venkatachalam, P

2018-06-01

Natural rubber (cis-1, 4-polyisoprene) is being produced from bark laticifer cells of Hevea brasiliensis and the popular high latex yielding Indian rubber clones are easily prone to onset of tapping panel dryness syndrome (TPD) which is considered as a physiological syndrome affecting latex production either partially or completely. This report describes an efficient protocol for development of transgenic rubber plants by over-expression of 3-hydroxy 3-methylglutaryl Co-enzyme A reductase 1 (hmgr1) gene which is considered as rate limiting factor for latex biosynthesis via Agrobacterium-mediated transformation. The pBIB plasmid vector containing hmgr1 gene cloned under the control of a super-promoter was used for genetic transformation using embryogenic callus. Putatively transgenic cell lines were obtained on selection medium and produced plantlets with 44% regeneration efficiency. Transgene integration was confirmed by PCR amplification of 1.8 kb hmgr1 and 0.6 kb hpt genes from all putatively transformed callus lines as well as transgenic plants. Southern blot analysis showed the stable integration and presence of transgene in the transgenic plants. Over expression of hmgr1 transgene was determined by Northern blot hybridization, semi-quantitative PCR and real-time PCR (qRT-PCR) analysis. Accumulation of hmgr1 mRNA transcripts was more abundant in transgenic plants than control. Increased level of photosynthetic pigments, protein contents and HMGR enzyme activity was also noticed in transgenic plants over control. Interestingly, the latex yield was significantly enhanced in all transgenic plants compared to the control. The qRT-PCR results exhibit that the hmgr1 mRNA transcript levels was 160-fold more abundance in transgenic plants over untransformed control. These results altogether suggest that there is a positive correlation between latex yield and accumulation of mRNA transcripts level as well as HMGR enzyme activity in transgenic rubber plants. It is presumed that there is a possibility for enhanced level of latex biosynthesis in transgenic plants as the level of mRNA transcripts and HMGR enzyme activity is directly correlated with latex yield in rubber tree. Further, the present results clearly suggest that the quantification of HMGR enzyme activity in young seedlings will be highly beneficial for early selection of high latex yielding plants in rubber breeding programs. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

40 CFR 428.111 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.111 Specialized... term “raw material” shall mean all latex solids used in the manufacture of latex foam. ...

40 CFR 428.111 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.111 Specialized... term “raw material” shall mean all latex solids used in the manufacture of latex foam. ...

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad; Ismail, Hanafi

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed bymore » using scanning electron microscopy (SEM)« less

Comparative Transcriptome Analysis of Latex Reveals Molecular Mechanisms Underlying Increased Rubber Yield in Hevea brasiliensis Self-Rooting Juvenile Clones

PubMed Central

Li, Hui-Liang; Guo, Dong; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

Rubber tree (Hevea brasiliensis) self-rooting juvenile clones (JCs) are promising planting materials for rubber production. In a comparative trial between self-rooting JCs and donor clones (DCs), self-rooting JCs exhibited better performance in rubber yield. To study the molecular mechanism associated with higher rubber yield in self-rooting JCs, we sequenced and comparatively analyzed the latex of rubber tree self-rooting JCs and DCs at the transcriptome level. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from the library of self-rooting JCs and DCs, respectively, by using Illumina HiSeq 2000 sequencing technology. De novo assemblies yielded 54689 unigenes from the library of self-rooting JCs and DCs. Among 54689 genes, 1716 genes were identified as differentially expressed between self-rooting JCs and DCs via comparative transcript profiling. Functional analysis showed that the genes related to the mass of categories were differentially enriched between the two clones. Several genes involved in carbohydrate metabolism, hormone metabolism and reactive oxygen species scavenging were up-regulated in self-rooting JCs, suggesting that the self-rooting JCs provide sufficient molecular basis for the increased rubber yielding, especially in the aspects of improved latex metabolisms and latex flow. Some genes encoding epigenetic modification enzymes were also differentially expressed between self-rooting JCs and DCs. Epigenetic modifications may lead to gene differential expression between self-rooting JCs and DCs. These data will provide new cues to understand the molecular mechanism underlying the improved rubber yield of H. brasiliensis self-rooting clones. PMID:27555864

Comparative Transcriptome Analysis of Latex Reveals Molecular Mechanisms Underlying Increased Rubber Yield in Hevea brasiliensis Self-Rooting Juvenile Clones.

PubMed

Li, Hui-Liang; Guo, Dong; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

Rubber tree (Hevea brasiliensis) self-rooting juvenile clones (JCs) are promising planting materials for rubber production. In a comparative trial between self-rooting JCs and donor clones (DCs), self-rooting JCs exhibited better performance in rubber yield. To study the molecular mechanism associated with higher rubber yield in self-rooting JCs, we sequenced and comparatively analyzed the latex of rubber tree self-rooting JCs and DCs at the transcriptome level. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from the library of self-rooting JCs and DCs, respectively, by using Illumina HiSeq 2000 sequencing technology. De novo assemblies yielded 54689 unigenes from the library of self-rooting JCs and DCs. Among 54689 genes, 1716 genes were identified as differentially expressed between self-rooting JCs and DCs via comparative transcript profiling. Functional analysis showed that the genes related to the mass of categories were differentially enriched between the two clones. Several genes involved in carbohydrate metabolism, hormone metabolism and reactive oxygen species scavenging were up-regulated in self-rooting JCs, suggesting that the self-rooting JCs provide sufficient molecular basis for the increased rubber yielding, especially in the aspects of improved latex metabolisms and latex flow. Some genes encoding epigenetic modification enzymes were also differentially expressed between self-rooting JCs and DCs. Epigenetic modifications may lead to gene differential expression between self-rooting JCs and DCs. These data will provide new cues to understand the molecular mechanism underlying the improved rubber yield of H. brasiliensis self-rooting clones.

Allergenic proteins of natural rubber latex.

PubMed

Yeang, H Y; Arif, Siti Arija M; Yusof, Faridah; Sunderasan, E

2002-05-01

As the living cytoplasm of laticiferous cells, Hevea brasiliensis latex is a rich blend of organic substances that include a mélange of proteins. A small number of these proteins have given rise to the problem of latex allergy. The salient characteristics of H. brasiliensis latex allergens that are recognized by the International Union of Immunological Societies (IUIS) are reviewed. These are the proteins associated with the rubber particles, the cytosolic C-serum proteins and the B-serum proteins that originate mainly from the lutoids. Procedures for the isolation and purification of latex allergens are discussed, from latex collection in the field to various preparative approaches adopted in the laboratory. As interest in recombinant latex allergens increases, there is a need to validate recombinant proteins to ascertain equivalence with their native counterparts when used in immunological studies, diagnostics, and immunotherapy. Copyright 2002 Elsevier Science (USA).

Identification of natural rubber and characterization of rubber biosynthetic activity in fig tree.

PubMed

Kang, H; Kang, M Y; Han, K H

2000-07-01

Natural rubber was extracted from the fig tree (Ficus carica) cultivated in Korea as part of a survey of rubber producing plants. Fourier transform infrared and (13)C nuclear magnetic resonance analysis of samples prepared by successive extraction with acetone and benzene confirmed that the benzene-soluble residues are natural rubber, cis-1,4-polyisoprene. The rubber content in the latex of fig tree was about 4%, whereas the rubber content in the bark, leaf, and fruit was 0.3%, 0.1%, and 0.1%, respectively. Gel-permeation chromatography revealed that the molecular size of the natural rubber from fig tree is about 190 kD. Similar to rubber tree (Hevea brasiliensis) and guayule (Parthenium argentatum Gray), rubber biosynthesis in fig tree is tightly associated with rubber particles. The rubber transferase in rubber particles exhibited a higher affinity for farnesyl pyrophosphate than for isopentenyl pyrophosphate, with apparent K(m) values of 2.8 and 228 microM, respectively. Examination of latex serum from fig tree by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed major proteins of 25 and 48 kD in size, and several proteins with molecular mass below 20 and above 100 kD. Partial N-terminal amino acid sequencing and immunochemical analyses revealed that the 25- and 48-kD proteins were novel and not related to any other suggested rubber transferases. The effect of EDTA and Mg(2+) ion on in vitro rubber biosynthesis in fig tree and rubber tree suggested that divalent metal ion present in the latex serum is an important factor in determining the different rubber biosynthetic activities in fig tree and rubber tree.

Identification of Natural Rubber and Characterization of Rubber Biosynthetic Activity in Fig Tree1

PubMed Central

Kang, Hunseung; Kang, Min Young; Han, Kyung-Hwan

2000-01-01

Natural rubber was extracted from the fig tree (Ficus carica) cultivated in Korea as part of a survey of rubber producing plants. Fourier transform infrared and 13C nuclear magnetic resonance analysis of samples prepared by successive extraction with acetone and benzene confirmed that the benzene-soluble residues are natural rubber, cis-1,4-polyisoprene. The rubber content in the latex of fig tree was about 4%, whereas the rubber content in the bark, leaf, and fruit was 0.3%, 0.1%, and 0.1%, respectively. Gel-permeation chromatography revealed that the molecular size of the natural rubber from fig tree is about 190 kD. Similar to rubber tree (Hevea brasiliensis) and guayule (Parthenium argentatum Gray), rubber biosynthesis in fig tree is tightly associated with rubber particles. The rubber transferase in rubber particles exhibited a higher affinity for farnesyl pyrophosphate than for isopentenyl pyrophosphate, with apparent Km values of 2.8 and 228 μm, respectively. Examination of latex serum from fig tree by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed major proteins of 25 and 48 kD in size, and several proteins with molecular mass below 20 and above 100 kD. Partial N-terminal amino acid sequencing and immunochemical analyses revealed that the 25- and 48-kD proteins were novel and not related to any other suggested rubber transferases. The effect of EDTA and Mg2+ ion on in vitro rubber biosynthesis in fig tree and rubber tree suggested that divalent metal ion present in the latex serum is an important factor in determining the different rubber biosynthetic activities in fig tree and rubber tree. PMID:10889262

21 CFR 878.4460 - Surgeon's glove.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Identification. A surgeon's glove is a device made of natural or synthetic rubber intended to be worn by... used in the glove is excluded. (b) Classification. Class I (general controls). [53 FR 23872, June 24...

Test and Evaluation for Chemical Resistance of Gloves Worn for Protection against Exposure to H-70 Hydrazine.

DTIC Science & Technology

1980-07-01

Edmont-Wilson 37-165 NBR .056 (22) 10 J Edmont-Wilson 26-665 Rubber .046 (18) 10 K Edmont-Wilson 36-755 Rubber .102 (40) 10 L Surety 10-112L Nitrile...4367 Dickenson & Company Charleston SC 29405 Coshocton OH 43812 International Playtex Company Surety Rubber Company Industrial Gloves Division P.O. Box...B Pioneer A-10 Nitrile .025 (10) 9 C Pioneer A-15 Nitrile .038 (15) 9 D Norton NSN 8415-00-753-6551 Butyl rubber .076 (30) M E Norton NSN 8415-01-025

The rubber tree genome shows expansion of gene family associated with rubber biosynthesis.

PubMed

Lau, Nyok-Sean; Makita, Yuko; Kawashima, Mika; Taylor, Todd D; Kondo, Shinji; Othman, Ahmad Sofiman; Shu-Chien, Alexander Chong; Matsui, Minami

2016-06-24

Hevea brasiliensis Muell. Arg, a member of the family Euphorbiaceae, is the sole natural resource exploited for commercial production of high-quality natural rubber. The properties of natural rubber latex are almost irreplaceable by synthetic counterparts for many industrial applications. A paucity of knowledge on the molecular mechanisms of rubber biosynthesis in high yield traits still persists. Here we report the comprehensive genome-wide analysis of the widely planted H. brasiliensis clone, RRIM 600. The genome was assembled based on ~155-fold combined coverage with Illumina and PacBio sequence data and has a total length of 1.55 Gb with 72.5% comprising repetitive DNA sequences. A total of 84,440 high-confidence protein-coding genes were predicted. Comparative genomic analysis revealed strong synteny between H. brasiliensis and other Euphorbiaceae genomes. Our data suggest that H. brasiliensis's capacity to produce high levels of latex can be attributed to the expansion of rubber biosynthesis-related genes in its genome and the high expression of these genes in latex. Using cap analysis gene expression data, we illustrate the tissue-specific transcription profiles of rubber biosynthesis-related genes, revealing alternative means of transcriptional regulation. Our study adds to the understanding of H. brasiliensis biology and provides valuable genomic resources for future agronomic-related improvement of the rubber tree.

Severe latex allergy after a vaginal examination during labor: a case report.

PubMed

Santos, R; Hernández-Ayup, S; Galache, P; Morales, F G; Batiza, V A; Montoya, D

1997-12-01

There has been an alarming increase in latex allergy, which can be a potential cause of occupational atopic disease. Physicians should be aware of this entity in high-risk groups and in patients with other allergies. A 32-year-old pregnant woman, with an allergy to orange juice, was first seen with a 39-week pregnancy in the labor room, where she had on two occasions a severe atopic reaction when examined with a latex glove. A latex allergy was suspected, and management with hydrocortisone resulted in remission of symptoms. Two hours later a vaginal delivery was performed with nonlatex, nonvinyl gloves. A week later immunoglobulin E antilatex antibodies determined by radioallergosorbent test were still positive at 585 IU. It is concluded that symptoms of latex allergy may develop in high-risk groups or in those with other known allergies. Because of the increasing frequency of this entity, physicians should take greater care and give more attention to the clinical history, as well as be aware of this possibility in these groups of patients.

Structural characterization of alpha-terminal group of natural rubber. 1. Decomposition of branch-points by lipase and phosphatase treatments.

PubMed

Tarachiwin, Lucksanaporn; Sakdapipanich, Jitladda; Ute, Koichi; Kitayama, Tatsuki; Bamba, Takashi; Fukusaki, Ei-Ichiro; Kobayashi, Akio; Tanaka, Yasuyuki

2005-01-01

Deproteinized natural rubber latex (DPNR-latex) was treated with lipase and phosphatase in order to analyze the structure of the chain-end group (alpha-terminal). The enzymatic treatment decreased the content of long-chain fatty acid ester groups in DPNR from about 6 to 2 mol per rubber molecule. The molecular weight and intrinsic viscosity were reduced to about one-third after treatment with lipase and phosphatase. The Huggins' k' constant of the enzyme-treated DPNR showed the formation of linear rubber molecules. The molecular weight distribution of DPNR changed apparently after treatment with lipase and phosphatase. (1)H NMR spectrum of rubber obtained from DPNR-latex showed small signals due to monophosphate, di-phosphate and phospholipids at the alpha-terminus. Treatment of DPNR-latex with lipase and phosphatase decreased the relative intensity of the (1)H NMR signals corresponding to phospholipids, whereas no change was observed for the signals due to mono- and diphosphates. The residual mono- and diphosphate signals as well as some phospholipid signals after lipase and phosphatase treatments indicate that mono- and diphosphate groups are directly linked at the alpha-terminus with the modified structure, expected by aggregation or linking with phospholipid molecules.

Demonstration/Validation of the TC-60 Controlled Detonation Chamber, Porton Down, UK: Final Demonstration Test Report

DTIC Science & Technology

2007-06-01

Joint At the exit of the expansion tank, a polymeric composition of ethylene-propylene- diene terpolymer ( EPDM ) rubber was used to mate the flange of...The final connection of the detonator was cumbersome for an operator wearing thick butyl rubber gloves. The detonator wire connection was made to a...operators were required to wear PPE, including rubber gloves. The decision was made to transfer the PLC components to outside the VCS. In Phase I, the

Evaluation of a Lightweight Protective Mask Concept for Respiratory Protection System 21

DTIC Science & Technology

1992-01-01

In addition, the LPM should provide a comfortable fit to reduce the physiological burden on the solder. The M40 mask is molded of silicone rubber ...for low temperature flexibility and romfort even though this material doesn’t providr. a good chemical agent barrier. Also, the M40 uses thick rubber ...Latex BL-100 (Appeadix D, no. 32) with natural rubber latex 1041, (Firestone), and by evenly mixing polyisobutylene latem I (PIB-5C) with natural

Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex

PubMed Central

Chow, Keng-See; Mat-Isa, Mohd.-Noor; Bahari, Azlina; Ghazali, Ahmad-Kamal; Alias, Halimah; Mohd.-Zainuddin, Zainorlina; Hoh, Chee-Choong; Wan, Kiew-Lian

2012-01-01

The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees. PMID:22162870

Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex.

PubMed

Chow, Keng-See; Mat-Isa, Mohd-Noor; Bahari, Azlina; Ghazali, Ahmad-Kamal; Alias, Halimah; Mohd-Zainuddin, Zainorlina; Hoh, Chee-Choong; Wan, Kiew-Lian

2012-03-01

The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees.

Evaluation of peptides release using a natural rubber latex biomembrane as a carrier.

PubMed

Miranda, M C R; Borges, F A; Barros, N R; Santos Filho, N A; Mendonça, R J; Herculano, R D; Cilli, E M

2018-05-01

The biomembrane natural (NRL-Natural Rubber Latex), manipulated from the latex obtained from the rubber tree Hevea brasiliensis, has shown great potential for application in biomedicine and biomaterials. Reflecting the biocompatibility and low bounce rate of this material, NRL has been used as a physical barrier to infectious agents and for the controlled release of drugs and extracts. The aim of the present study was to evaluate the incorporation and release of peptides using a latex biomembrane carrier. After incorporation, the release of material from the membrane was observed using spectrophotometry. Analyses using HPLC and mass spectroscopy did not confirm the release of the antimicrobial peptide [W 6 ]Hylin a1 after 24 h. In addition, analysis of the release solution showed new compounds, indicating the degradation of the peptide by enzymes contained in the latex. Additionally, the release of a peptide with a shorter sequence (Ac-WAAAA) was evaluated, and degradation was not observed. These results showed that the use of NRL as solid matrices as delivery systems of peptide are sequence dependent and could to be evaluated for each sequence.

Involvement of Two Latex-Clearing Proteins during Rubber Degradation and Insights into the Subsequent Degradation Pathway Revealed by the Genome Sequence of Gordonia polyisoprenivorans Strain VH2

PubMed Central

Hiessl, Sebastian; Schuldes, Jörg; Thürmer, Andrea; Halbsguth, Tobias; Bröker, Daniel; Angelov, Angel; Liebl, Wolfgang; Daniel, Rolf

2012-01-01

The increasing production of synthetic and natural poly(cis-1,4-isoprene) rubber leads to huge challenges in waste management. Only a few bacteria are known to degrade rubber, and little is known about the mechanism of microbial rubber degradation. The genome of Gordonia polyisoprenivorans strain VH2, which is one of the most effective rubber-degrading bacteria, was sequenced and annotated to elucidate the degradation pathway and other features of this actinomycete. The genome consists of a circular chromosome of 5,669,805 bp and a circular plasmid of 174,494 bp with average GC contents of 67.0% and 65.7%, respectively. It contains 5,110 putative protein-coding sequences, including many candidate genes responsible for rubber degradation and other biotechnically relevant pathways. Furthermore, we detected two homologues of a latex-clearing protein, which is supposed to be a key enzyme in rubber degradation. The deletion of these two genes for the first time revealed clear evidence that latex-clearing protein is essential for the microbial utilization of rubber. Based on the genome sequence, we predict a pathway for the microbial degradation of rubber which is supported by previous and current data on transposon mutagenesis, deletion mutants, applied comparative genomics, and literature search. PMID:22327575

Micropunctures of rubber gloves used in oral surgery.

PubMed

Skaug, N

1976-10-01

In 720 operations in ambulatory oral surgery, the 2,880 surgical rubber gloves used were tested at the end of operation for perforations not earlier detected (microperforations). Gloves of ordinary thickness (type A) and of a thicker quality (type B) were examined. Perforations were found in 1495% and 22.0% of type A gloves and in 3.2% and 2.0% of type B gloves when oral surgeons and dental students, respectively, were operators. Gloves worn by operation assistants showed a lower incidence of perforation. Before operation, 50 gloves of type A were punctured at the tip of right index finger by a sterile dental probe. Results of bacteriologic examinations of the right index and middle fingers strongly indicated that a high number of bacteria passed through pinholes in the gloves. The intact surgical glove represents an impermeable barrier, protecting not only the operation wound against skin bacteria from the hands of the oral surgeon, but also the oral surgeon against pathogenic microorganisms, in particular hepatitis virus type B, escaping from the oral cavity of the patient.

Latex improvement of recycled asphalt pavement

NASA Astrophysics Data System (ADS)

Drennon, C.

1982-08-01

The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

Effect of two types of latex gloves and surfactants on polymerization inhibition of three polyvinylsiloxane impression materials.

PubMed

Peregrina, Alejandro; Land, Martin F; Feil, Phillip; Price, Connie

2003-09-01

Polymerization inhibition of polyvinylsiloxane impression materials has been reported when in sustained contact with some types of latex gloves. This study examined the polymerization inhibition of 3 polyvinylsiloxane impression materials placed in contact with surfaces subjected to prior contact with gloves or commonly used surfactants. A 2 x 3 x 4 x 2 design was used (n = 20), with 2 types of gloves (powdered and unpowdered), 3 types of polyvinylsiloxane impression materials (Aquasil, Extrude, and Affinis), 4 surfactant conditions (water, soap/water-rinse, alcohol, and unexposed), and 2 ambient temperatures of 22 degrees C and 36 degrees C. After glove exposure to surfactants, a glass surface was subjected to rubbing contact with the treated glove for a standardized time. After drying, automixed polyvinylsiloxane impression materials were dispensed onto the treated surface. Specimens were removed and evaluated for polymerization inhibition at the manufacturer's recommended polymerization time (36 degrees C), or after 15 minutes at 22 degrees C. Specimens were rated as polymerized, or as inhibited if any polyvinylsiloxane residue remained on the slab. A chi-square analysis was used to evaluate the results (alpha=.05). Setting inhibition was found only with one of the polyvinylsiloxane materials when alcohol was used as a surfactant. At 22 degrees C, the inhibition rate ranged from 95% to 100% for both glove types; at 36 degrees C inhibition ranged from 40% (unpowdered gloves) to 75% (powdered gloves), respectively. Under these in vitro conditions, glove exposure to alcohol resulted in polymerization inhibition of 1 of 3 tested polyvinylsiloxane impression materials (Extrude).

Isolation and identification of some unknown substances in disposable nitrile-butadiene rubber gloves used for food handling.

PubMed

Mutsuga, M; Wakui, C; Kawamura, Y; Maitani, T

2002-11-01

In Japan, disposable gloves made from nitrile-butadiene rubber (NBR) are frequently used in contact with foods. In a previous paper, we investigated substances migrating from various gloves made of polyvinyl chloride, polyethylene, natural rubber and NBR. Zinc di-n-butyldithiocarbamate (ZDBC), diethyldithiocarbamate (ZDEC) used as vulcanization accelerators, di(2-ethylhexyl)phthalate (DEHP) used as a plasticizer and many unknown compounds that migrated from NBR gloves into n-heptane were detected by GC/MS. In this paper, six unknown compounds were obtained from one kind of NBR glove by n-hexane extraction and each was isolated by silica gel chromatography. From the results of NMR and mass spectral analysis of the six unknown compounds, their structures are proposed as 1,4-dione-2,5-bis(1,1-dimethylpropyl)cyclohexadiene (1), 2-(1,1-dimethylethyl)-4-(1,1,3,3-tetra methylbutyl)phenol (2), 2,6-bis(1,1-dimethylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (3), 2,4-bis(1,1,3,3-tetramethylbutyl)phenol (4), 2-(1,1-dimethylethyl)4,6-bis(1,1,3,3-tetramethylbutyl)phenol (5) and 2,4,6-tris(1,1,3,3-tetramethylbutyl)phenol (6). Compound 1 was observed in five of the seven kinds of NBR gloves, and compounds 2-4 and 6, which are not listed in Chemical Abstract (CA), were present in four kinds of gloves.

78 FR 15370 - Draft Guidance for Industry and Food and Drug Administration Staff: Recommendations for Labeling...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-11

... Product Container Is Not Made With Natural Rubber Latex.'' The purpose of this draft guidance is to make recommendations on the appropriate language to include in the labeling of a medical product to convey that natural... Products To Inform Users That the Product or Product Container Is Not Made With Natural Rubber Latex...

Reinforcement effect of soy protein nanoparticles in amine-modified natural rubber latex

USDA-ARS?s Scientific Manuscript database

Mechanical properties of natural rubber reinforced with soy protein nanoparticles are useful for various rubber applications. However, the properties is further improved by improving interactions between soy protein and rubber. A novel method is used to modify particle surface of natural rubber late...

The rubber tree genome shows expansion of gene family associated with rubber biosynthesis

PubMed Central

Lau, Nyok-Sean; Makita, Yuko; Kawashima, Mika; Taylor, Todd D.; Kondo, Shinji; Othman, Ahmad Sofiman; Shu-Chien, Alexander Chong; Matsui, Minami

2016-01-01

Hevea brasiliensis Muell. Arg, a member of the family Euphorbiaceae, is the sole natural resource exploited for commercial production of high-quality natural rubber. The properties of natural rubber latex are almost irreplaceable by synthetic counterparts for many industrial applications. A paucity of knowledge on the molecular mechanisms of rubber biosynthesis in high yield traits still persists. Here we report the comprehensive genome-wide analysis of the widely planted H. brasiliensis clone, RRIM 600. The genome was assembled based on ~155-fold combined coverage with Illumina and PacBio sequence data and has a total length of 1.55 Gb with 72.5% comprising repetitive DNA sequences. A total of 84,440 high-confidence protein-coding genes were predicted. Comparative genomic analysis revealed strong synteny between H. brasiliensis and other Euphorbiaceae genomes. Our data suggest that H. brasiliensis’s capacity to produce high levels of latex can be attributed to the expansion of rubber biosynthesis-related genes in its genome and the high expression of these genes in latex. Using cap analysis gene expression data, we illustrate the tissue-specific transcription profiles of rubber biosynthesis-related genes, revealing alternative means of transcriptional regulation. Our study adds to the understanding of H. brasiliensis biology and provides valuable genomic resources for future agronomic-related improvement of the rubber tree. PMID:27339202

Allergic reaction to latex: a risk factor for unsuspected anaphylaxis.

PubMed

Warpinski, J R; Folgert, J; Cohen, M; Bush, R K

1991-01-01

Allergic reactions to latex, including anaphylaxis may be a problem in certain individuals exposed to latex. Four atopic patients with symptoms of rhinitis, asthma, anaphylaxis, and/or urticaria upon contact with latex products were studied. The patients showed IgE binding to latex RAST disks ranging from 1.0 to 27.3 times the negative control. Latex products (gloves, balloons, and condoms) directly bound IgE from all four patients. Eluted proteins from the latex products inhibited IgE binding to commercial latex RAST disks. SDS-PAGE demonstrated multiple latex protein bands by Coomassie Blue staining between 14 and 66 kD. Immunoblotting showed specific IgE binding to latex proteins at 30 and 66 kD. These results indicate that latex-allergic patients have IgE directed against specific latex proteins. Allergy to latex can pose a substantial health risk to susceptible individuals.

Evaluation of apparent viscosity of Para rubber latex by diffuse reflection near-infrared spectroscopy.

PubMed

Sirisomboon, Panmanas; Chowbankrang, Rawiphan; Williams, Phil

2012-05-01

Near-infrared spectroscopy in diffuse reflection mode was used to evaluate the apparent viscosity of Para rubber field latex and concentrated latex over the wavelength range of 1100 to 2500 nm, using partial least square regression (PLSR). The model with ten principal components (PCs) developed using the raw spectra accurately predicted the apparent viscosity with correlation coefficient (r), standard error of prediction (SEP), and bias of 0.974, 8.6 cP, and -0.4 cP, respectively. The ratio of the SEP to the standard deviation (RPD) and the ratio of the SEP to the range (RER) for the prediction were 4.4 and 16.7, respectively. Therefore, the model can be used for measurement of the apparent viscosity of field latex and concentrated latex in quality assurance and process control in the factory.

Latex allergy in women's health care.

PubMed

Fletcher, Joanne

2013-01-01

Latex allergy in midwifery and women's health care is not a new concept, with numerous case reports documenting adverse reactions in pregnant women to natural rubber latex in the birthing room. The practising midwife, nurse and sonographer need to be aware of the signs and symptoms of latex allergy and the implications of a severe reaction to latex not only to the woman but also the unborn child.

40 CFR 63.498 - Back-end process provisions-recordkeeping.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be the crumb rubber dry weight of the rubber leaving the stripper. (iv) The organic HAP content of... be the crumb rubber dry weight of the crumb rubber leaving the stripper. (iii) The hourly average of... test runs. (1) The uncontrolled residual organic HAP content in the latex or dry crumb rubber, as...

40 CFR 63.498 - Back-end process provisions-recordkeeping.

Code of Federal Regulations, 2012 CFR

2012-07-01

... be the crumb rubber dry weight of the rubber leaving the stripper. (iv) The organic HAP content of... be the crumb rubber dry weight of the crumb rubber leaving the stripper. (iii) The hourly average of... test runs. (1) The uncontrolled residual organic HAP content in the latex or dry crumb rubber, as...

40 CFR 63.498 - Back-end process provisions-recordkeeping.

Code of Federal Regulations, 2014 CFR

2014-07-01

... be the crumb rubber dry weight of the rubber leaving the stripper. (iv) The organic HAP content of... be the crumb rubber dry weight of the crumb rubber leaving the stripper. (iii) The hourly average of... test runs. (1) The uncontrolled residual organic HAP content in the latex or dry crumb rubber, as...

40 CFR 63.498 - Back-end process provisions-recordkeeping.

Code of Federal Regulations, 2013 CFR

2013-07-01

... be the crumb rubber dry weight of the rubber leaving the stripper. (iv) The organic HAP content of... be the crumb rubber dry weight of the crumb rubber leaving the stripper. (iii) The hourly average of... test runs. (1) The uncontrolled residual organic HAP content in the latex or dry crumb rubber, as...

Effect of combination ultrasonic and ball milling techniques of commercial fillers dispersion on mechanical properties of natural rubber (NR) latex films

NASA Astrophysics Data System (ADS)

Hamran, Noramirah; Rashid, Azura A.

2017-07-01

Commercial fillers such as silica and carbon black generally impart the reinforcing effects in dry rubber compound, but have an adverse effect on Natural rubber (NR) latex compounds. The addition of commercial fillers in NR latex has reduced the mechanical properties of NR latex films due to the destabilization effect in the NR latex compounds which govern by the dispersion quality, particle size and also the pH of the dispersion itself. The ball milling process is the conventional meth od of preparation of dispersions and ultrasonic has successfully used in preparation of nano fillers such as carbon nanotube (CNT). In this study the combination between the conventional methods; ball milling together the ultrasonic method were used to prepare the silica and carbon black dispersions. The different duration of ball milling (24, 48 and 72 hours) was compared with the ultrasonic method (30, 60, 90 and 120 minutes). The combination of ball milling and ultrasonic from the optimum individual technique was used to investigate the reduction of particle size of the fillers. The particle size analyzer, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) test were carried out to investigate the obtained particle size and the tensile and tear test were carried out to investigate the mechanical properties of the NR latex films. The reduction of filler particle size is expected to impart the properties of NR latex films.

Condoms - male

MedlinePlus

... Rubbers; Male condoms; Contraceptive - condom; Contraception - condom; Barrier method - condom ... infections.) Latex rubber Polyurethane Condoms are the only method of birth control for men that are not ...

[Migrants from disposable gloves and residual acrylonitrile].

PubMed

Wakui, C; Kawamura, Y; Maitani, T

2001-10-01

Disposable gloves made from polyvinyl chloride with and without di(2-ethylhexyl) phthalate (PVC-DEHP, PVC-NP), polyethylene (PE), natural rubber (NR) and nitrile-butadiene rubber (NBR) were investigated with respect to evaporation residue, migrated metals, migrants and residual acrylonitrile. The evaporation residue found in n-heptane was 870-1,300 ppm from PVC-DEHP and PVC-NP, which was due to the plasticizers. Most of the PE gloves had low evaporation residue levels and migrants, except for the glove designated as antibacterial, which released copper and zinc into 4% acetic acid. For the NR and NBR gloves, the evaporation residue found in 4% acetic acid was 29-180 ppm. They also released over 10 ppm of calcium and 6 ppm of zinc into 4% acetic acid, and 1.68-8.37 ppm of zinc di-ethyldithiocarbamate and zinc di-n-butyldithiocarbamate used as vulcanization accelerators into n-heptane. The acrylonitrile content was 0.40-0.94 ppm in NBR gloves.

Rubber particle proteins REF1 and SRPP1 interact differently with native lipids extracted from Hevea brasiliensis latex.

PubMed

Wadeesirisak, Kanthida; Castano, Sabine; Berthelot, Karine; Vaysse, Laurent; Bonfils, Frédéric; Peruch, Frédéric; Rattanaporn, Kittipong; Liengprayoon, Siriluck; Lecomte, Sophie; Bottier, Céline

2017-02-01

Rubber particle membranes from the Hevea latex contain predominantly two proteins, REF1 and SRPP1 involved in poly(cis-1,4-isoprene) synthesis or rubber quality. The repartition of both proteins on the small or large rubber particles seems to differ, but their role in the irreversible coagulation of the rubber particle is still unknown. In this study we highlighted the different modes of interactions of both recombinant proteins with different classes of lipids extracted from Hevea brasiliensis latex, and defined as phospholipids (PL), glycolipids (GL) and neutral lipids (NL). We combined two biophysical methods, polarization modulated-infrared reflection adsorption spectroscopy (PM-IRRAS) and ellipsometry to elucidate their interactions with monolayers of each class of lipids. REF1 and SRPP1 interactions with native lipids are clearly different; SRPP1 interacts mostly in surface with PL, GL or NL, without modification of its structure. In contrast REF1 inserts deeply in the lipid monolayers with all lipid classes. With NL, REF1 is even able to switch from α-helice conformation to β-sheet structure, as in its aggregated form (amyloid form). Interaction between REF1 and NL may therefore have a specific role in the irreversible coagulation of rubber particles. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative Analysis of Latex Transcriptome Reveals Putative Molecular Mechanisms Underlying Super Productivity of Hevea brasiliensis

PubMed Central

Li, Heping; Fan, Yujie; Yang, Jianghua; Qi, Jiyan; Li, Huibo

2013-01-01

Increasing demand for natural rubber prompts studies into the mechanisms governing the productivity of rubber tree ( Hevea brasiliensis ). It is very interesting to notice that a rubber tree of clone PR107 in Yunnan, China is reported to yield more than 20 times higher than the average rubber tree. This super-high-yielding (SHY) rubber tree (designated as SY107), produced 4.12 kg of latex (cytoplasm of rubber producing laticifers, containing about 30% of rubber) per tapping, more than 7-fold higher than that of the control. This rubber tree is therefore a good material to study how the rubber production is regulated at a molecular aspect. A comprehensive cDNA-AFLP transcript profiling was performed on the latex of SY107 and its average counterparts by using the 384 selective primer pairs for two restriction enzyme combinations (ApoI/MseI and TaqI/MseI). A total of 746 differentially expressed (DE) transcript-derived fragments (TDFs) were identified, of which the expression patterns of 453 TDFs were further confirmed by RT-PCR. These RT-PCR confirmed TDFs represented 352 non-redundant genes, of which 215 had known or partially known functions and were grouped into 10 functional categories. The top three largest categories were transcription and protein synthesis (representing 24.7% of the total genes), defense and stress (15.3%), and primary and secondary metabolism (14.0%). Detailed analysis of the DE-genes suggests notable characteristics of SHY phenotype in improved sucrose loading capability, rubber biosynthesis-preferred sugar utilization, enhanced general metabolism and timely stress alleviation. However, the SHY phenotype has little correlation with rubber-biosynthesis pathway genes. PMID:24066172

Comparison of 4 different types of surgical gloves used for preventing blood contact.

PubMed

Wittmann, Andreas; Kralj, Nenad; Köver, Jan; Gasthaus, Klaus; Lerch, Hartmut; Hofmann, Friedrich

2010-05-01

Needlestick injuries are always associated with a risk of infection, because these types of punctures may expose healthcare workers to a patient's blood and/or body fluids. To compare the efficacy of 4 different types of surgical gloves for preventing exposure to blood as a result of needlestick injury. For simulation of needlestick injury, a circular sample of pork skin was tightened onto a bracket, and a single finger from a medical glove was stretched over the sample. First, a powder-free surgical glove with a gel coating was used to test blood contact. Second, a glove with a patented puncture indication system was used to test blood contact with a double-gloved hand. Third, 2 powder-free latex medical gloves of the same size and hand were combined for double gloving, again to test blood contact. Finally, we tested a glove with an integrated disinfectant on the inside. The punctures were carried out using diverse sharp surgical devices that were contaminated with (99)Tc-marked blood. The amount of blood contact was determined from the transmitted radioactivity. For the powder-free surgical glove with a gel coating, a mean volume of 0.048 microL of blood (standard error of the mean [SEM], 0.077 microL) was transferred in punctures with an automated lancet at a depth of 2.4 mm through 1 layer of latex. For the glove with an integrated disinfectant on the inside, the mean volume of blood transferred was 0.030 microL (SEM, 0.0056 microL) with a single glove and was 0.024 microL (SEM, 0.003 microL) with 2 gloves. For the glove with the patented puncture indication system, a mean volume of 0.024 microL (SEM, 0.003 microL) of blood was transferred. Double gloving or the use of a glove with disinfectant can result in a decrease in the volume of blood transferred. Therefore, the use of either of these gloving systems could help to minimize the risk of bloodborne infections for medical staff.

Proteomics analysis of latex from Hevea brasiliensis (clone RRIM 600).

PubMed

Habib, Mohd Afiq Hazlami; Yuen, Gan Chee; Othman, Fazilah; Zainudin, Nurul Nabilah; Latiff, Aishah Abdul; Ismail, Mohd Nazri

2017-04-01

The natural rubber latex extracted from the bark of Hevea brasiliensis plays various important roles in today's modern society. Following ultracentrifugation, the latex can be separated into 3 layers: C-serum, lutoids, and rubber particles. Previous studies have shown that a large number of proteins are present in these 3 layers. However, a complete proteome for this important plant is still unavailable. Protein sequences have been recently translated from the completed draft genome database of H. brasiliensis, leading to the creation of annotated protein databases of the following H. brasiliensis biosynthetic pathways: photosynthesis, latex allergens, rubberwood formation, latex biosynthesis, and disease resistance. This research was conducted to identify the proteins contained within the latex by way of de novo sequencing from mass spectral data obtained from the 3 layers of the latex. Peptides from these proteins were fragmented using collision-induced dissociation, higher-energy collisional dissociation, and electron-transfer dissociation activation methods. A large percentage of proteins from the biosynthetic pathways (63% to 100%) were successfully identified. In addition, a total of 1839 unique proteins were identified from the whole translated draft genome database (AnnHBM).

The physical and degradation properties of starch-graft-acrylonitrile/carboxylated nitrile butadiene rubber latex films.

PubMed

Misman, M A; Azura, A R; Hamid, Z A A

2015-09-05

Starch-graft-acrylonitrile (ANS) is compounded with carboxylated nitrile butadiene rubber (XNBR) latex. The control XNBR and the ANS/XNBR latex films were prepared through a coagulant dipping process. The films were subjected to ageing and soil burial procedures. For the biodegradation experiment, the surface of the film was assessed after the 2nd, 4th and 8th week of soil burial. The ANS, XNBR, and ANS/XNBR colloidal stability were determined with a Malvern Zetasizer. For the dipped latex films, the mechanical, morphological and thermal properties were analyzed. The addition of ANS into the XNBR latex increased the stability of the colloidal dispersions, decreased the latex film tensile strength, but increased the elongation at break due to the bipolar interaction of the ANS and XNBR particles. The ANS/XNBR latex films aged faster than the control films while the morphological analysis showed the existence of a starch crystal region and the formation of microbial colonies on the surfaces of the films. Based on the TGA-DTA curves, a higher ΔT was observed for the ANS/XNBR latex films signifying high thermal energy needed for the film to thermally degrade. Copyright © 2015 Elsevier Ltd. All rights reserved.

Surgical glove perforation in cardiac surgery.

PubMed

Driever, R; Beie, M; Schmitz, E; Holland, M; Knapp, M; Reifschneider, H J; Hofmann, F; Vetter, H O

2001-12-01

Recently, concern for the protection of health care employees and health care recipients has led to increasing awareness of transmitted infections. Sterile surgical gloves were tested to determine the incidence of perforations after being worn during procedures commonly performed by cardiac surgeons. In a prospective study conducted from January 15, 2000 through February 15, 2000, 953 gloves worn during cardiac surgery were evaluated for punctures. Pairs of sterile latex surgical gloves were collected over a period of one month. Routine tasks included mainly bypass and valve surgery. Impermeability was tested by means of a water retention test according to European standard EN 455 Part 1 performed on 954 (Manufix, Hartmann, Germany) latex gloves. A control group of 50 unused gloves was also evaluated for the presence of spontaneous leakage. Gloves were separated according to whether the wearer was an operator (254 gloves), first assistant (220 gloves), second assistant (272 gloves), or theatre nurse (207 gloves). Gloves with a known perforation occurring during the procedure were not included in the study. There were no punctures in the 50 unused gloves. Punctures were detected in 66 of 254 (26.0 %) gloves used by operators, 49 of 220 (22.3 %) used by first assistants, 25 of 272 (9.2 %) used by second assistants, and 78 of 207 (37.7 %) used by theatre nurses. Some gloves had more than one puncture, accounting for the 244 holes detected (operators 75/244 = 30.7 %; first assistants 54/244 = 22.1 %; second assistants 28/244 = 11.5 %; theatre nurses 87/244 = 35.7 %). Sites of scalpel and suture needle injuries were most commonly the thumb (27.3 %) and pointer finger (42.1 %) of the non-dominant hand, followed by, in descending order: middle finger (10.2 %), other fingers (15.7 %), palm (3.8 %) and back of the hand (0.9 %). The number of punctures that occur during cardiac operations is obviously higher than has so far been assumed. Therefore, cardiac surgeons should consider the incidence of unknown glove perforations when planning surgery in patients with infectious diseases.

Elastic MCF Rubber with Photovoltaics and Sensing on Hybrid Skin (H-Skin) for Artificial Skin by Utilizing Natural Rubber: Third Report on Electric Charge and Storage under Tension and Compression †.

PubMed

Shimada, Kunio

2018-06-06

In the series of studies on new types of elastic and compressible artificial skins with hybrid sensing functions, photovoltaics, and battery, we have proposed a hybrid skin (H-Skin) by utilizing an electrolytically polymerized magnetic compound fluid (MCF) made of natural rubber latex (NR-latex). By using the experimental results in the first and second reports, we have clarified the feasibility of electric charge at irradiation, and that without illumination under compression and elongation. The former was explained in a wet-type MCF rubber solar cell by developing a tunneling theory together with an equivalent electric circuit model. The latter corresponds to the battery rather than to the solar cell. As for the MCF rubber battery, depending on the selected agent type, we can make the MCF rubber have higher electricity and lighter weight. Therefore, the MCF rubber has an electric charge and storage whether at irradiation or not.

16 CFR 1630.4 - Test procedure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... a fire-retardant treatment, or is made of fibers which have had a fire-retardant treatment, the...) Gloves. Nonhygroscopic gloves (such as rubber polyethylene) for handling the sample after drying, and...

16 CFR 1631.4 - Test procedure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... a fire-retardant treatment, or is made of fibers which have had a fire-retardant treatment, the... gel desiccant. (7) Gloves. Nonhygroscopic gloves (such as rubber or polyethylene) for handling the...

16 CFR 1630.4 - Test procedure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... a fire-retardant treatment, or is made of fibers which have had a fire-retardant treatment, the...) Gloves. Nonhygroscopic gloves (such as rubber polyethylene) for handling the sample after drying, and...

16 CFR 1631.4 - Test procedure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... a fire-retardant treatment, or is made of fibers which have had a fire-retardant treatment, the... gel desiccant. (7) Gloves. Nonhygroscopic gloves (such as rubber or polyethylene) for handling the...

EXHIBIT - SPACESUITS

NASA Image and Video Library

1982-02-08

S82-26645 (March 1982) --- Spacesuit inner gloves consist of pressure bladders covered by Beta Cloth. EVA outer gloves are made of Beta Cloth, Mylar and a metallic mesh hand area. The thumb and fingertips of the glove are molded of silicone rubber to permit a degree of sensitivity. The inner gloves attach to the suit by pressure sealing rings, similar to these used in helmet-to-suit connections. The outer gloves served as a cover to protect from micrometeorites, abrasions and heat.

Hand eczema and occupational contact allergies in healthcare workers with a focus on rubber additives.

PubMed

Hamnerius, Nils; Svedman, Cecilia; Bergendorff, Ola; Björk, Jonas; Bruze, Magnus; Engfeldt, Malin; Pontén, Ann

2018-06-20

Hand eczema (HE) in healthcare workers (HCWs) is common. Besides wet work, healthcare work also implies exposure to contact allergens. To assess HE and contact allergy related to occupational exposures in HCWs. In a cross-sectional study, 311 HCWs with HE within the preceding 12 months and a control group of 114 HCWs without HE were investigated with the baseline series and a special patch test series based on substances found in the gloves, soaps, alcoholic hand disinfectants and hand creams provided at the hospitals. Contact allergy to rubber additives was significantly more common in HCWs with HE (6%) than in HCWs without HE (1%, P = .02). The corresponding percentages for fragrances were 11% and 3%, respectively (P = .004). Occupational HE was found in 193 of 311 (62%) HCWs. Of these, 22 of 193 (11%) had occupational allergic contact dermatitis, including 17 with glove-related rubber contact allergy. Contact allergy to diphenylguanidine was as common as contact allergy to thiurams. Occupational contact allergy to rubber additives was significantly associated with sick-leave related to HE. Contact allergy to rubber additives in medical gloves is the most common cause of occupational allergic contact dermatitis in HCWs. Aimed patch testing with relevant rubber additives is mandatory when HE in HCWs is investigated. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mechanical Enhancement of Sensitivity in Natural Rubber Using Electrolytic Polymerization Aided by a Magnetic Field and MCF for Application in Haptic Sensors

PubMed Central

Shimada, Kunio; Saga, Norihiko

2016-01-01

Sensors are essential to the fulfillment of every condition of haptic technology, and they need simultaneously to sense shear stress as well as normal force, and temperature. They also must have a strong and simple structure, softness, and large extension. To achieve these conditions simultaneously, we enhanced the sensitivity of sensors utilizing natural rubber (NR)-latex through the application of electrolytic polymerization focused on the isoprene C=C bonds in natural rubbers such as NR-latex, and then applied a magnetic field and magnetic compound fluid (MCF) as magnetically responsive fluid. When an electric field alone was used in the rubber, the effect of electrolytic polymerization was very small compared to the effect in well-known conductive polymer solution such as plastic. The MCF developed by Shimada in 2001 involved magnetite and metal particles, and acts as a filler in NR-latex. By utilizing the magnetic, electric fields and the MCF, we aligned the electrolytically polymerized C=C along the magnetic field line with the magnetic clusters formed by the aggregation of magnetite and metal particles so as to enhance the effect of electrolytic polymerization. We then demonstrated the effectiveness of the new method of rubber vulcanization on the sensitivity of the rubber by experimentally investigating its electric and dynamic characteristics. PMID:27649210

Mechanical Enhancement of Sensitivity in Natural Rubber Using Electrolytic Polymerization Aided by a Magnetic Field and MCF for Application in Haptic Sensors.

PubMed

Shimada, Kunio; Saga, Norihiko

2016-09-18

Sensors are essential to the fulfillment of every condition of haptic technology, and they need simultaneously to sense shear stress as well as normal force, and temperature. They also must have a strong and simple structure, softness, and large extension. To achieve these conditions simultaneously, we enhanced the sensitivity of sensors utilizing natural rubber (NR)-latex through the application of electrolytic polymerization focused on the isoprene C=C bonds in natural rubbers such as NR-latex, and then applied a magnetic field and magnetic compound fluid (MCF) as magnetically responsive fluid. When an electric field alone was used in the rubber, the effect of electrolytic polymerization was very small compared to the effect in well-known conductive polymer solution such as plastic. The MCF developed by Shimada in 2001 involved magnetite and metal particles, and acts as a filler in NR-latex. By utilizing the magnetic, electric fields and the MCF, we aligned the electrolytically polymerized C=C along the magnetic field line with the magnetic clusters formed by the aggregation of magnetite and metal particles so as to enhance the effect of electrolytic polymerization. We then demonstrated the effectiveness of the new method of rubber vulcanization on the sensitivity of the rubber by experimentally investigating its electric and dynamic characteristics.

A glove-likeability study of specially-treated gloves in the detonator manufacturing and packaging industry

DOE PAGES

Cournoyer, Michael E.; Lawton, Cindy M.; Lounsbury, James B.; ...

2016-03-22

We use hand gloves (hereafter referred to as gloves) in the detonator manufacturing and packaging operations. As part of a process improvement program, new glove formulations have been considered that lower the overall risk of detonator operations by reducing ergonomic injury factors. Gloves with a specially treated surface for extra grip and control are now commercially available and have been recommended for use in detonator operations. A Glove Likeability Study demonstrated that detonator manufacturing and packaging workers prefer gloves with a specially treated surface over currently approved gloves made from latex and nitrile formulations. Glove material compatibility tests indicate thatmore » the recommended gloves are as compatible if not more compatible as the currently approved gloves for working with secondary explosives. Thus, these gloves with a specially treated surface for extra grip and control are now available for tasks where sensitivity and fingertip control are crucial. Replacement of the current gloves with gloves with a specially treated surface improves the safety configuration of detonator manufacturing and packaging operations.« less

A glove-likeability study of specially-treated gloves in the detonator manufacturing and packaging industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cournoyer, Michael E.; Lawton, Cindy M.; Lounsbury, James B.

We use hand gloves (hereafter referred to as gloves) in the detonator manufacturing and packaging operations. As part of a process improvement program, new glove formulations have been considered that lower the overall risk of detonator operations by reducing ergonomic injury factors. Gloves with a specially treated surface for extra grip and control are now commercially available and have been recommended for use in detonator operations. A Glove Likeability Study demonstrated that detonator manufacturing and packaging workers prefer gloves with a specially treated surface over currently approved gloves made from latex and nitrile formulations. Glove material compatibility tests indicate thatmore » the recommended gloves are as compatible if not more compatible as the currently approved gloves for working with secondary explosives. Thus, these gloves with a specially treated surface for extra grip and control are now available for tasks where sensitivity and fingertip control are crucial. Replacement of the current gloves with gloves with a specially treated surface improves the safety configuration of detonator manufacturing and packaging operations.« less

Study of Antibacterial Activity and Bacteriology of Latex from Asclepias syriaca L

PubMed Central

McCay, Steven; Mahlberg, Paul

1973-01-01

Whole and fractionated latex of Asclepias syriaca was tested for antimicrobial or growth-promoting activity with 16 genera and species of bacteria. Latex and extracted fractions (distilled water, acetic acid, sodium bicarbonate, sulfuric acid, and ethyl ether) possessed no detectable antimicrobial activity. Comparison of growth curves of selected bacteria incubated with serum and rubber fractions, as well as controls, revealed no detectable inhibition of growth, except for a slight inhibitory response to autoclaved serum. Most bacteria were capable of utilizing latex for a substrate as indicated by the increased growth rate in the exponential phase. The stationary phase was entered simultaneously by both the treated cultures and the controls. Various bacteria cultured in a litmus latex mixture yielded populations which ranged from <104 organisms/ml for Lactobacillus casei, Staphylococcus aureus and Micrococcus lysodeikticus to 1.1 × 1010 organisms/ml for Clostridium acetobutylicum. Whole latex, as well as the serum and rubber fractions, support the growth of various bacteria, but under field conditions there is no evidence for systemic infection of this type of cell by bacteria. PMID:4790590

A new penetration test method: protection efficiency of glove and clothing materials against diphenylmethane diisocyanate (MDI).

PubMed

Henriks-Eckerman, Maj-Len; Mäkelä, Erja

2015-03-01

Reported cases of allergic contact dermatitis caused by methylenediphenyl diisocyanate (MDI) have increased and thereby increased the need for adequate skin protection. Current standardized permeation and penetration test methods give information about efficacy of protective materials against individual components of the polyurethane systems. They do not give information of what kind of clothing materials workers should wear against splashes when handling mixed MDI-polyurethane formulations, which contain MDI, its oligomers, and polyols. The aim of this study was to develop and validate a sensitive penetration test method that can be used to select clothing that is protective enough against uncured splashes of MDI-polyurethane, still easy to use, and also, to find affordable glove materials that provide adequate protection during a short contact. The penetration of MDI through eight representative glove or clothing materials was studied with the developed test procedure. One MDI hardener and two polymeric MDI (PMDI)-polyol formulations representing different curing times were used as test substances. The materials tested included work clothing (woven) fabric, arm shields (nonwoven fabric), old T-shirt, winter gloves, and gloves of nitrile rubber, leather, vinyl (PVC), and natural rubber. A drop (50 µl) of test substance was added to the outer surface of the glove/clothing material, which had Tape Fixomull attached to the inner surface as a collection medium. After penetration times of 5 or 20min, the collecting material was removed and immediately immersed into acetonitrile containing 1-(2-methoxyphenyl)-piperazine for derivatization. The formed urea derivatives of 2,4'-MDI and 4,4'-MDI were analysed using liquid chromatography with mass spectrometric and UV detection. The precision of the test method was good for the material with high penetration (work clothing fabric) of MDI, as the relative standard deviation (RSD) was 14 and 20%. For the arm shield with a low penetration (the nonwoven fabric), the precision was lower with RSDs of 35 and 50%. For two clothing materials, the penetration was high (134-577 µg cm(-2)). Low penetration (<0.5 µg cm(-2)) was shown by the arm shield and the natural rubber glove. Three glove materials showed no detectable MDI penetration (<0.002 µg cm(-2)). Two affordable glove materials (natural rubber and nitrile rubber) and one clothing material (dust proof arm shield) that can provide adequate protection during short contact with solvent free PMDI formulations were found. The new test procedure should be standardized in order to get a new international penetration standard. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Unraveling the mystery of natural rubber biosythesis part I: investigation of the composition and growth of in vitro natural rubber using high resolution size exclusion chromatography

USDA-ARS?s Scientific Manuscript database

Monitoring the growth of in vitro natural rubberwas accomplished by high resolution size exclusion chromatography, SEC.Washed rubber particles isolated from H. brasiliensis latex, containing the rubber transferase enzyme, were used to catalyze the polymerization of synthetic isopentenyl pyrophosphat...

Dermal in vitro penetration of methiocarb, paclobutrazol, and pirimicarb: effect of nonylphenolethoxylate and protective gloves.

PubMed Central

Nielsen, J B; Andersen, H R

2001-01-01

Dermal exposure has become the major route of human occupational exposure to pesticides. Detergents are used as part of formulated pesticide products and are known to change the barrier properties of human skin in vitro. However, studies on the influence of detergents as well as protective glove materials on dermal penetration of pesticides are scarce. In an experiment using in vitro static diffusion cells mounted with human skin, we evaluated the effect of nonylphenol-ethoxylate on dermal penetration of three extensively used pesticides--methiocarb, paclobutrazol, and pirimicarb--and the protection against dermal penetration offered by protective gloves made of latex or nitrile. There was a general tendency, though not statistically significant for all pesticides, for nonylphenolethoxylate to decrease the percutaneous penetration of the three pesticides. The nitrile generally offered better protection against percutaneous penetration of pesticides than did latex, but the degree of protection decreased over time and depended on the pesticides used. PMID:11266321

Development of hand exoskeleton for rehabilitation of post-stroke patient

NASA Astrophysics Data System (ADS)

Zaid, Amran Mohd; Chean, Tee Chu; Sukor, Jumadi Abdul; Hanafi, Dirman

2017-10-01

Degenerative muscle diseases characterized by loss of strength in human hand significantly affect the physical of affected individuals. A soft assistive exoskeleton glove is designed to help post-stroke patient with their rehabilitation process. The glove uses soft bending actuator which has a rubber like tender characteristic. Due to its rubber like characteristic, flexion of finger can be achieved easily through pneumatic air without considering other hand motions. The application involves a post-stroke patient to wear the soft exoskeleton glove on his paralyzed hand and control the actuation of the glove by using pneumatic air source. The fabrication of the soft bending actuator involves silicone rubber Mold Star® 15 SLOW which falls within the soft category of shore A hardness scale. The soft bending actuator is controlled by Arduino Mega 2560 as main controller board and relay module is used to trigger the 3/2-way single solenoid valve by switching on the 24VDC power supply. The actuation of the soft bending actuator can be manipulated by setting delay ON and OFF for the relay switching. Thus, the repetition of the bending motion can be customized to fulfil the rehabilitation needs of the patient.

Effect of irradiation on the prevulcanized latex/low nitrosamines latex blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Pairu; Zin, Wan Manshol Wan; Daik, Rusli

2015-09-25

Radiation Prevulcanized Natural Rubber Latex (RVNRL) was blended with Low Nitrosamines Latex (LNL) at different composition ratio. Methyl Metachrylate (MMA) was added for grafting onto the blended latex. Blended latex was subjected to gamma irradiation at various doses up to 8kGy. The mechanical properties and FTIR analysis were investigated as a function of the blended composition and irradiation dose. It was found that blending at specific ratio and gamma irradiation at specific dose led to significant improvement on the properties of the latex. The optimum mechanical properties was attained at a total blending ratio of 70% RVNRL and 30% ofmore » LNL.« less

Polyphenoloxidase Silencing Affects Latex Coagulation in Taraxacum Species1[W

PubMed Central

Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M.; Moerschbacher, Bruno M.; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

2009-01-01

Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution. PMID:19605551

Evaluation of the protective effectiveness of gloves from occupational exposure to 2-methoxyethanol using the biomarkers of 2-methoxyacetic acid levels in the urine and plasma

PubMed Central

Chang, H; Lin, C; Shih, T; Chan, H; Chou, J; Huang, Y

2004-01-01

Aims: To evaluate the protective effectiveness of gloves from occupational exposure to 2-methoxyethanol (2-ME); and to examine the association of 2-methoxyacetic acid (MAA) in urine and plasma collected simultaneously from low 2-ME exposure and high 2-ME exposure workers in a semiconductor copper laminate circuit board manufacturing plant. Methods: Eight hour time weighted breathing zone monitoring was performed to verify the 2-ME exposure classification between workers in regular and special operations. Urine and plasma samples were simultaneously collected from 74 exposed and 80 non-exposed workers. MAA concentrations in the urine (UMAA) and plasma (PMAA) were measured using previously published methods. Three types of gloves worn by workers (cotton, rubber, and no gloves) were recorded by direct observations in the workplace and validated by person-to-person interview. Protective effectiveness indices (PEI) were used to evaluate the glove effectiveness. Results: There was no detectable 2-ME/MAA in the air, or in urine and plasma samples in non-exposed workers. The average UMAA and PMAA in special operations were 72.63 mg/g Cr. and 29.72 mg/l, significantly higher than values in regular operations (5.44 mg/g Cr. and 2.58 mg/l, respectively). PMAA showed satisfactory correlation to UMAA in all participants from both regular and special operations. The rubber gloves provided significant reduction in 2-ME uptake, whereas cotton gloves provided little protection with fluctuating effectiveness, based on PEI estimates. Conclusions: PMAA, similar to UMAA, could serve as a specific biomarker for 2-ME exposure. Wearing impermeable rubber gloves during high risk tasks can reduce major 2-ME exposure. Other improvements, including engineering control, should be provided to diminish worker exposure to 2-ME in occupational environments. PMID:15258277

Composite Material Hazard Assessment at Crash Sites

DTIC Science & Technology

2015-01-01

advanced composite materials. All personnel involved in rescue in close crash-site proximity are required to wear self -contained breathing apparatus...close crash-site proximity are required to wear self -contained breathing apparatus, chemical protective clothing, leather gloves, and neoprene...Take extra precaution when handling these materials. Nitrile rubber gloves can be worn underneath the leather gloves to provide chemical hazard

Iodinated natural rubber latex: preparation, characterisation & antibacterial activity assessment.

PubMed

Tyagi, M; Singh, S; Singh, H

2000-11-01

Natural Rubber (NR) in both its latex and dried form was treated with iodine to make it antibacterial in nature. The NR latex was dried and washed, dissolved in toluene, iodinated and cast into films. In a different approach, NR in its latex form (emulsion) was blended with aqueous solution of povidone-iodine complex (PVP-I) and films were cast. Phase separation of PVP-I was observed in the films prepared using NR latex; whereas the film prepared using NR solution in toluene and molecular iodine were homogeneous, transparent light brown. Solubility assessment of the films revealed that unlike pure NR, the iodinated NR failed to go into solution completely. The films obtained from both the approaches were evaluated for release of iodide ions. On immersion in water, PVP-I blended latex did not retain iodine while sustained release of iodide ion was observed in case of dried NR dissolved in toluene and treated with iodine. The FT-IR spectra of the iodinated films revealed that iodine attaches covalently to the double bonds in the isoprene units of NR. The films were also evaluated for their antibacterial properties and it was observed that the films prepared from both the approaches, acquired antimicrobial properties.

The Effects of Industrial Protective Gloves and Hand Skin Temperatures on Hand Grip Strength and Discomfort Rating

PubMed Central

2017-01-01

Daily working activities and functions require a high contribution of hand and forearm muscles in executing grip force. To study the effects of wearing different gloves on grip strength, under a variety of hand skin temperatures, an assessment of the maximum grip strength was performed with 32 healthy male workers with a mean age (standard deviation) of 30.44 (5.35) years wearing five industrial gloves at three hand skin temperatures. Their ages and anthropometric characteristics including body mass index (BMI), hand length, hand width, hand depth, hand palm, and wrist circumference were measured. The hand was exposed to different bath temperatures (5 °C, 25 °C, and 45 °C) and hand grip strength was measured using a Jamar hydraulic hand dynamometer with and without wearing the gloves (chemical protection glove, rubber insulating glove, anti-vibration impact glove, cotton yarn knitted glove, and RY-WG002 working glove). The data were analyzed using the Shapiro–Wilk test, Pearson correlation coefficient, Tukey test, and analysis of variance (ANOVA) of the within-subject design analysis. The results showed that wearing gloves significantly affected the maximum grip strength. Wearing the RY-WG002 working glove produced a greater reduction on the maximum grip when compared with the bare hand, while low temperatures (5 °C) had a significant influence on grip when compared to medium (25 °C) and high (45 °C) hand skin temperatures. In addition, participants felt more discomfort in both environmental extreme conditions. Furthermore, they reported more discomfort while wearing neoprene, rubber, and RY-WG002 working gloves. PMID:29207573

BIO-OIL FROM GUAYULE BAGASSE

USDA-ARS?s Scientific Manuscript database

Guayule, Parthenium argentatum, has recently been commercialized as a domestic source of rubber, primarily sold as latex for circum-allergenic medical applications. Latex extraction leaves ~90% of the crop biomass as a finely-divided, free flowing feedstock suitable for conversion to biofuels. Fast ...

Study on the Secant Segmentation Algorithm of Rubber Tree

NASA Astrophysics Data System (ADS)

Li, Shute; Zhang, Jie; Zhang, Jian; Sun, Liang; Liu, Yongna

2018-04-01

Natural rubber is one of the most important materials in the national defense and industry, and the tapping panel dryness (TPD) of the rubber tree is one of the most serious diseases that affect the production of rubber. Although considerable progress has been made in the more than 100 years of research on the TPD, there are still many areas to be improved. At present, the method of artificial observation is widely used to identify TPD, but the diversity of rubber tree secant symptoms leads to the inaccurate judgement of the level of TPD. In this paper, image processing technology is used to separate the secant and latex, so that we can get rid of the interference factors, get the exact secant and latex binary image. By calculating the area ratio of the corresponding binary images, the grade of TPD can be classified accurately. and can also provide an objective basis for the accurate identification of the tapping panel dryness (TPD) level.

Mechanical properties of melt-processed polymer blend of amorphous corn flour composite filler and styrene-butadiene rubber

USDA-ARS?s Scientific Manuscript database

The corn flour composite fillers were prepared by blending corn flour with rubber latex, dried, and cryogenically ground into powders, which were then melt-blended with rubber polymers in an internal mixer to form composites with enhanced mechanical properties. The composites prepared with melt-blen...

Reinforcing Natural Rubber with Cellulose Nanofibrils Extracted from Bleached Eucalyptus Kraft Pulp

Treesearch

Chunmei Zhang; Tianliang Zhai; Ronald Sabo; Craig Clemons; Yi Dan; Lih-Sheng Turng

2014-01-01

Reinforced natural rubber (NR) nanocomposites were prepared by solution mixing, casting, and evaporation of pre-vulcanized natural rubber latex and an aqueous suspension of cellulose nanofibrils (CNFs) extracted from bleached eucalyptus kraft pulp. Scanning electron microscopy (SEM) images showed that there were no micro-scaled aggregates observed in the nanocomposites...

Characterization of interaction between natural rubber and silica by FTIR

NASA Astrophysics Data System (ADS)

Jarnthong, Methakarn; Liao, Lusheng; Zhang, Fuquan; Wang, Yueqiong; Li, Puwang; Peng, Zheng; Malawet, Chutarat; Intharapat, Punyanich

2017-05-01

Blending of natural rubber (NR) and nanosilica (SiO2) was performed in latex state. The mechanical properties of NR/SiO2 nanocomposites at various filler contents were investigated. The interactions of unvulcanized natural rubber and nanosilica filler were characterized using Fourier Transform Infrared (FTIR)-Attenuated Total Reflectance (ATR) spectroscopy. The relationship between mechanical properties and rubber-filler interaction was discussed.

Complete genome sequence of Streptomyces sp. strain CFMR 7, a natural rubber degrading actinomycete isolated from Penang, Malaysia.

PubMed

Nanthini, Jayaram; Chia, Kim-Hou; Thottathil, Gincy P; Taylor, Todd D; Kondo, Shinji; Najimudin, Nazalan; Baybayan, Primo; Singh, Siddharth; Sudesh, Kumar

2015-11-20

Streptomyces sp. strain CFMR 7, which naturally degrades rubber, was isolated from a rubber plantation. Whole genome sequencing and assembly resulted in 2 contigs with total genome size of 8.248 Mb. Two latex clearing protein (lcp) genes which are responsible for rubber degrading activities were identified. Copyright © 2015 Elsevier B.V. All rights reserved.

Morphology and thermal stability of nano titanium dioxide filled natural rubber prepared by latex mixing method

NASA Astrophysics Data System (ADS)

Hayeemasae, N.; Surya, I.; Ismail, H.

2018-02-01

This paper deals with the morphology and thermal stability of nano Titanium Dioxide (TiO2) filled natural rubber composites. This study also suggests a new method of incorporating TiO2. Aqueous dispersions of nano TiO2at the loadings of 0, 2, 4, 6 and 8 phr were dispersed in natural rubber latex, the resulting compounds were then dried prior to mixing it with other ingredients on a two-roll mill. By applying this technique, the homogeneity of the compound is significantly improved. This can be clearly seen from the morphology observed. Adding TiO2 results in shifting the decomposition temperature and char residue irrespective of the loadings of nano TiO2.

Reinforcement of natural rubber latex by nanosize montmorillonite clay

NASA Astrophysics Data System (ADS)

Tantatherdtam, Rattana

Based on the unique character of montmorillonite namely its layer structure and the ability of silicate particles to separate into nanometer-size platelets, natural rubber (polyisoprene)/clay composites were obtained by mixing rubber latex with clay-water dispersion and coagulating the mixture. The resulting film had greatly improved mechanical properties compared with films using micron-sized fillers. Further, both modulus and toughness were improved; in many composite system an improvement in modulus leads to a loss of toughness. X-ray diffraction results indicated that clay platelets dispersed in the rubber matrix on the nanoscale level with some macromolecules intercalated into the clay gallery. The observed considerable improvement in mechanical properties, coupled with a theoretical model of composite modulus suggests a dispersed structure of clay in the composite. While not all clay particles are exfoliated, data suggest that a reasonable fraction of exfoliated materials is required to explain the experimental results.

Sucrose importation into laticifers of Hevea brasiliensis, in relation to ethylene stimulation of latex production

PubMed Central

Dusotoit-Coucaud, Anaïs; Brunel, Nicole; Kongsawadworakul, Panida; Viboonjun, Unchera; Lacointe, André; Julien, Jean-Louis; Chrestin, Hervé; Sakr, Soulaïman

2009-01-01

Background and Aims The major economic product of Hevea brasiliensis is a rubber-containing cytoplasm (latex), which flows out of laticifers (latex cells) when the bark is tapped. The latex yield is stimulated by ethylene. Sucrose, the unique precursor of rubber synthesis, must cross the plasma membrane through specific sucrose transporters before being metabolized in the laticifers. The relative importance of sucrose transporters in determining latex yield is unknown. Here, the effects of ethylene (by application of Ethrel®) on sucrose transporter gene expression in the inner bark tissues and latex cells of H. brasiliensis are described. Methods Experiments, including cloning sucrose transporters, real time RT-PCR and in situ hybridization, were carried out on virgin (untapped) trees, treated or untreated with the latex yield stimulant Ethrel. Key Results Seven putative full-length cDNAs of sucrose transporters were cloned from a latex-specific cDNA library. These transporters belong to all SUT (sucrose transporter) groups and differ by their basal gene expression in latex and inner soft bark, with a predominance of HbSUT1A and HbSUT1B. Of these sucrose transporters, only HbSUT1A and HbSUT2A were distinctly increased by ethylene. Moreover, this increase was shown to be specific to laticifers and to ethylene application. Conclusion The data and all previous information on sucrose transport show that HbSUT1A and HbSUT2A are related to the increase in sucrose import into laticifers, required for the stimulation of latex yield by ethylene in virgin trees. PMID:19567416

Unraveling the mystery of natural rubber biosynthesis. Part II. Composition and growth of in vitro natural rubber using high-resolution size exclusion chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiang, Cheng Ching K.; Barkakaty, Balaka; Puskas, Judit E.

The superior properties of natural rubber (cis-1,4-polyisoprene [NR]) are a function of its structure and composition, properties that still remain a mystery and that are irreplaceable by any synthetic rubber. NR from guayule (Parthenium argentatum) has been gaining special interest for its hypoallergenic properties while maintaining superior mechanical properties that are commonly associated with the Brazilian rubber tree (Hevea brasiliensis), the most common source of NR. Techniques exist to isolate washed rubber particles (WRPs) that contain enzymatically active rubber transferase, to study NR biosynthesis, and previous work on the in vitroNRgrowth in Hevea has demonstrated the presence of around 50wt%ofmore » a low molecular weight ([MW], Mn <10 000 g/mol) fraction. Structural and compositional analyses of this low MW fraction in Hevea are challenging due to the high protein content. Here, we discuss the analysis and composition of guayule latex and WRPs using high-resolution Size Exclusion Chromatography. We also discuss the composition of the soluble fraction of inactive guayule latex using matrix-assisted laser desorption ionization/time of flight mass spectrometry.« less

Glove perforation in hip and knee arthroplasty.

PubMed

Demircay, Emre; Unay, Koray; Bilgili, Mustafa G; Alataca, Gulum

2010-11-01

The transmission of blood-borne pathogens during surgery is a major concern. Surgical gloves are the primary barrier between the surgeon and the patient. Surgical procedures that need manual handling of bony surfaces or sharp instruments have the highest risk of glove perforations. The frequencies and the sites of surgical glove perforations in arthroplasty procedures were assessed. We assessed the surgical glove perforations in total hip and knee arthroplasty procedures. Double standard latex gloves were used. A total of 983 outer and 511 inner gloves were tested. The gloves of all the surgical team members were tested for perforations during the first and second hours of surgery. There were 18.4% outer and 8.4% inner glove perforations. The most frequent site of perforation was the second digit of the nondominant hand (25.5%). We found that hip and knee arthroplasty had significantly more glove perforation risk for the surgeon in the first half of the operation rather than the second half, and 57.8% of the perforations were at the index finger and the thumb. Arthroplasty procedures still have high glove perforation rates despite the use of double gloving with frequent changes. Extra augmentation of the gloves in selected areas of the hand, in addition to double gloving, may be safer and more cost-effective than double gloving alone.

Rubber Elongation Factor (REF), a Major Allergen Component in Hevea brasiliensis Latex Has Amyloid Properties

PubMed Central

Berthelot, Karine; Lecomte, Sophie; Estevez, Yannick; Coulary-Salin, Bénédicte; Bentaleb, Ahmed; Cullin, Christophe; Deffieux, Alain; Peruch, Frédéric

2012-01-01

REF (Hevb1) and SRPP (Hevb3) are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom. PMID:23133547

Rubber elongation factor (REF), a major allergen component in Hevea brasiliensis latex has amyloid properties.

PubMed

Berthelot, Karine; Lecomte, Sophie; Estevez, Yannick; Coulary-Salin, Bénédicte; Bentaleb, Ahmed; Cullin, Christophe; Deffieux, Alain; Peruch, Frédéric

2012-01-01

REF (Hevb1) and SRPP (Hevb3) are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.

Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, M. R.; Ahmad, W. Y. W.; Samsuri, A.

2010-03-11

The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367+-9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised.more » For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.« less

Evaluating the Rheological Properties of Waste Natural Rubber Latex Modified Binder

NASA Astrophysics Data System (ADS)

Khatijah Abu Bakar, Siti; Ezree Abdulah, Mohd; Mustafa Kamal, Mazlina; Rahman, Raha Abd; Arifin Hadithon, Kamarul; Buhari, Rosnawati; Tajudin, Saiful Azhar Ahmad

2018-03-01

Road surface is designed to be the durable surface material to sustain the traffic loading. However, due to physical and mechanical stress, pavement deterioration is accelerated. Thus, modifying conventional bitumen by improving its properties is seen as the best method to prolong pavement in-service life. The purpose of this paper is to study the effect of waste natural rubber (NR) latex on rheological properties of bitumen. Conventional bitumen PEN 80/100 was modified with different content of waste NR latex using a high shear mixer at temperature of 150°C. The modified binder properties were characterized by conducting physical test (i.e. softening point, penetration and penetration index) and rheological test (i.e. dynamic shear rheometer, DSR). Results showed that, the addition of waste NR latex improved the rheology properties, which indicates by improving of rutting factor (G*/sin δ). This properties improvement has also shows a potential to resist deformation on road surface despite of high traffic loading.

Effect of different concentrations of sodium dodecyl sulfate and additional anionic surfactant on properties of low protein natural rubber latex

NASA Astrophysics Data System (ADS)

Abdullah, Nurulhuda; Manaf, Siti Nor Qamarina; Hassan, Aziana Abu

2017-12-01

This paper describes the chemical deproteinization process of natural rubber latex (NRL) using chemical denaturants namely urea and sodium dodecyl sulfate (SDS). Commercial high ammoniated natural rubber latex (HANRL) was incubated with both denaturants - urea and SDS for selected period of time before centrifugation and characterization. The role of SDS in NRL deproteinization process was further elucidated by manipulating the concentration of SDS at 0.3 phr and 0.5 phr during the incubation process. It was found that the physical properties of NRL especially stability, were governed by the amount of SDS, whereby higher concentration of SDS used led to greater NRL stability. However, too much concentration of SDS in the system might cause detrimental effect on the properties of low protein NRL. The effects of additional anionic surfactant namely potassium laurate on the physical properties of low protein NRL and its stabilization were also scrutinized. Characterizations include nitrogen determination by Kjeldahl method, zeta potential, and morphological analysis by Field Emission Scanning Electron Microscopy (FESEM).

Does Flexible Arterial Tubing Retain More Hemodynamic Energy During Pediatric Pulsatile Extracorporeal Life Support?

PubMed

Wang, Shigang; Kunselman, Allen R; Ündar, Akif

2017-01-01

The objective of this study was to evaluate the hemodynamic performance and energy transmission of flexible arterial tubing as the arterial line in a simulated pediatric pulsatile extracorporeal life support (ECLS) system. The ECLS circuit consisted of a Medos Deltastream DP3 diagonal pump head, Medos Hilite 2400 LT oxygenator, Biomedicus arterial/venous cannula (10 Fr/14 Fr), 3 feet of polyvinyl chloride (PVC) arterial tubing or latex rubber arterial tubing, primed with lactated Ringer's solution and packed red blood cells (hematocrit 40%). Trials were conducted at flow rates of 300 to 1200 mL/min (300 mL/min increments) under nonpulsatile and pulsatile modes at 36°C using either PVC arterial tubing (PVC group) or latex rubber tubing (Latex group). Real-time pressure and flow data were recorded using a custom-based data acquisition system. Mean pressures and energy equivalent pressures (EEP) were the same under nonpulsatile mode between the two groups. Under pulsatile mode, EEPs were significantly great than mean pressure, especially in the Latex group (P < 0.05). There was no difference between the two groups with regards to pressure drops across ECLS circuit, but pulsatile flow created more pressure drops than nonpulsatile flow (P < 0.05). Surplus hemodynamic energy (SHE) levels were always higher in the Latex group than in the PVC group at all sites. Although total hemodynamic energy (THE) losses were higher under pulsatile mode compared to nonpulsatile mode, more THE was delivered to the pseudopatient, particularly in the Latex group (P < 0.05). The results showed that the flexible arterial tubing retained more hemodynamic energy passing through it under pulsatile mode while mean pressures and pressure drops across the ECLS circuit were similar between PVC and latex rubber arterial tubing. Further studies are warranted to verify our findings. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Abscisic acid-dependent regulation of small rubber particle protein gene expression in Taraxacum brevicorniculatum is mediated by TbbZIP1.

PubMed

Fricke, Julia; Hillebrand, Andrea; Twyman, Richard M; Prüfer, Dirk; Schulze Gronover, Christian

2013-04-01

Natural rubber is a high-molecular-mass biopolymer found in the latex of >2,500 plant species, including Hevea brasiliensis, Parthenium argentatum and Taraxacum spp. The active sites of rubber biosynthesis are rubber particles, which comprise a hydrophobic rubber core surrounded by a phospholipid monolayer membrane containing species-dependent lipids and associated proteins. Small rubber particle proteins are the most abundant rubber particle-associated proteins in Taraxacum brevicorniculatum (TbSRPPs) and may promote rubber biosynthesis by stabilizing the rubber particle architecture. We investigated the transcriptional regulation of genes encoding SRPPs and identified a bZIP transcription factor (TbbZIP.1) similar to the Arabidopsis thaliana ABI5-ABF-AREB subfamily, which is thought to include downstream targets of ABA and/or abiotic stress-inducible protein kinases. The TbbZIP.1 gene was predominantly expressed in laticifers and regulates the expression of TbSRPP genes in an ABA-dependent manner. The individual TbSRPP genes showed distinct induction profiles, suggesting diverse roles in rubber biosynthesis and stress adaptation. The potential involvement of TbSRPPs in the adaptation of T. brevicorniculatum plants to environmental stress is discussed based on our current knowledge of the stress-response roles of SRPPs and their homologs, and the protective function of latex and rubber against pathogens. Our data suggest that TbSRPPs contribute to stress tolerance in T. brevicorniculatum and that their effects are mediated by TbbZIP.1.

Characterization of the rubber tree metallothionein family reveals a role in mitigating the effects of reactive oxygen species associated with physiological stress.

PubMed

Huang, Yacheng; Fang, Yongjun; Long, Xiangyu; Liu, Linya; Wang, Jia; Zhu, Jinheng; Ma, Yanyan; Qin, Yunxia; Qi, Jiyan; Hu, Xinwen; Tang, Chaorong

2018-06-01

Metallothioneins (MTs) as reactive oxygen species (ROS) scavengers play important roles in stress response and heavy metal homeostasis. In Hevea brasiliensis (the para rubber tree that is the source of commercial natural rubber) and in other trees, the functions of MTs are not well understood. Latex exudes when the rubber tree is tapped. The flow of latex and its regeneration can be enhanced by tapping, wounding and ethylene treatment, all of which produce ROS as a by-product. Here, we show the presence of four MT genes in H. brasiliensis, comprising three Type 2 (HbMT2, -2a and -2b) and one Type 3 (HbMT3L) isoforms, representing one of the smallest MT gene families among angiosperms. The four HbMTs exhibited distinct tissue expression patterns: HbMT2 and HbMT3L mainly in leaves, HbMT2a specifically in flowers and HbMT2b in diverse tissues. The expression of HbMT2b, an isoform present in latex, decreased significantly in the latex following the stress-inducing treatments of tapping, wounding and ethephon (an ethylene generator). The expressions of the leaf-abundant isoforms, HbMT2 and -3L were up-regulated following pathogenic fungus infection and high-temperature stress, but down-regulated by low-temperature stress. These reactions were consistent with multiple defense- and hormone-responsive cis-acting elements in the HbMT promoters. Nine transcription factors were shown to implicate in the high-temperature responsiveness of HbMT2 and -3L in leaves. Overexpression of HbMT2 in Escherichia coli enhanced the bacterium's tolerance to heavy metals and ROS, consistent with its predicted role as an ROS scavenger. Taken together, our results, along with other relevant studies, suggest an important role of HbMTs in latex regeneration as well as species adaptation via the regulation of ROS homeostasis.

Electricity remains a serious workplace hazard.

PubMed

Proctor, Laura; Kuchibotla, Srin

2013-08-01

Anyone who works in an industrial environment or is employed in the utility, mass transit, industrial goods manufacturing, or telecommunications industry - as well as many others - may be at risk for electrocution. Electric shock costs workers' lives and results in painful and debilitating injuries every year. Lockout/tagout procedures protect against electrocution, as do rubber insulating gloves, which must be worn any time workers are exposed to energized parts operating at 50 volts or higher. Some newer styles of rubber insulating gloves not only protect against electric shock, but also offer the dexterity and flexibility workers need for hours of comfortable wear.

PAH and soot emissions from burning components of medical waste: examination/surgical gloves and cotton pads.

PubMed

Levendis, Y A; Atal, A; Carlson, J B; Quintana, M D

2001-01-01

This is a laboratory investigation on the emissions from batch combustion of representative infectious ("red bag") medical waste components, such as medical examination latex gloves and sterile cotton pads. Plastics and cloth account for the majority of the red bag wastes by mass and, certainly, by volume. An electrically heated, horizontal muffle furnace was used for batch combustion of small quantities of shredded fuels (0.5-1.5 g) at a gas temperature of approximately 1000 degrees C. The residence time of the post-combustion gases in the furnace was approximately 1 s. At the exit of the furnace, the following emissions were measured: CO, CO2, NOx, particulates and polynuclear aromatic compounds (PACs). The first three gaseous emissions were measured with continuous gas analyzers. Soot and PAC emissions were simultaneously measured by passing the furnace effluent through a filter (to collect condensed-phase PACs) and a bed of XAD-4 adsorbent (to capture gaseous-phase PACs). Analysis involved soxhlet extraction, followed by gas chromatography-mass spectrometry (GC-MS). Results were contrasted with previously measured emissions from batch combustion of pulverized coal and tire-derived fuel (TDF) under similar conditions. Results showed that the particulate soot) and cumulative PAC emissions from batch combustion of latex gloves were more than an order of magnitude higher than those from cotton pads. The following values are indicative of the relative trends (but not necessarily absolute values) in emission yields: 26% of the mass of the latex was converted to soot, 11% of which was condensed PAC. Only 2% of the mass of cotton pads was converted to soot, and only 3% of the weight of that soot was condensed PAC. The PAC yields from latex were comparable to those from TDF. The PAC yields from cotton were higher than those from coal. A notable exception to this trend was that the three-ring gas-phase PAC yields from cotton were more significant than those from latex. Emission yields of CO and CO2 from batch combustion of cotton were, respectively, comparable and higher than those from latex, despite the fact that the carbon content of cotton was half that of latex. This is indicative of the more effective combustion of cotton. Nearly all of the mass of carbon of cotton gasified to CO and CO2 while only small fractions of the carbon in latex were converted to CO2 and CO (20% and 10%, respectively). Yields of NOx from batch combustions of latex and cotton accounted for 15% and 12%, respectively, of the mass of fuel nitrogen indicating that more fuel nitrogen was converted to NOx in the former case, possibly due to higher flame temperatures. No SO2 emissions were detected, indicating that during the fuel-rich combustion of latex, its sulfur content was converted to other compounds (such as H2S) or remained in the soot.

Evaluation experimentale de l'efficacite des gants de protection contre les nanoparticules de dioxyde de titane dans des conditions de travail

NASA Astrophysics Data System (ADS)

Vinches, Ludwig

Manufactured titanium dioxide nanoparticles (nTiO2) enter into the formulation of several commercial products including cosmetics, paints, varnishes or food. An increasing number of people will be exposed to nanoparticles (NP), in particular, scientists during their research and workers in companies. As such, they are an emerging source of hazard. Indeed, an increasing number of studies are warning against their likely harmful effects on health. The International Agency for Research against Cancer has classified nTiO2 as being possibly carcinogenic to humans. Furthermore some studies have shown that the skin is not an impervious membrane to the NP and that NP penetration is possible when the skin is injured by abrasion, after repeated flexions or even intact. Therefore, dermal protection will be necessary in order to thoroughly protect NP users. Based upon the precautionary principle, gloves should be used as protection against chemicals. However, to the best of our knowledge, no study on their resistance towards NP has been conducted. In this study, the performance of protective gloves was evaluated with respect to nTiO2 solutions and powders, under conditions simulating occupational use. Mechanical deformations, simulating those produced by hand flexing, were applied to nitrile and butyl rubber and latex samples that were in contact with nTiO2 in water, in propylene glycol or in powder form. nTiO 2 penetration through the protective gloves was determined after deformations of the materials. Following these results, the physicochemical and mechanical phenomena that facilitate the penetration of nTiO2 were identified and studied. It was shown that mechanical deformations caused both damage to the sample surface but also a change in the degree of crystallinity of the glove material. Strain energy was also measured. It decreased significantly in presence and absence of nTiO2, indicating a weakening of the polymer chains. A qualitative study showed that repetitive deformations also lead to a decrease in the size of the agglomerates that were contained in the nTiO2 powder. Glove materials that were in contact with colloidal solutions produced a swelling phenomenon. Finally, measurements of the elongation of glove samples immersed in colloidal solutions were used to determine diffusion coefficients across the materials. The transport of the nanoparticles was driven by that of the carrier liquid (water or propylene glycol). Given the carrier solutions and nanoparticles could be transported through the gloves, exposure to skin could occur.

Glove box shield

DOEpatents

Brackenbush, L.W.; Hoenes, G.R.

A shield for a glove box housing radioactive material is comprised of spaced apart clamping members which maintain three overlapping flaps in place therebetween. There is a central flap and two side flaps, the side flaps overlapping at the interior edges thereof and the central flap extending past the intersection of the side flaps in order to insure that the shield is always closed when the user wthdraws his hand from the glove box. Lead loaded neoprene rubber is the preferred material for the three flaps, the extent of lead loading depending upon the radiation levels within the glove box.

[Identification of migrants from nitrile-butadiene rubber gloves].

PubMed

Mutsuga, Motoh; Kawamura, Yoko; Wakui, Chiseko; Maitani, Tamio

2003-04-01

Polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate are restricted for food contact use. In their place, disposable gloves made from nitrile-butadiene rubber (NBR) are used in contact with foodstuffs. Some unknown substances were found to migrate into n-heptane from NBR gloves. By GC/MS, HR-MS and NMR, their chemical structures were confirmed to be 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (used as a plasticizer), 4,4'-butylidenedi(6-tert-butyl-m-cresol), a mixture of styrenated phenols consisting of 2-(alpha-methylbenzyl)phenol, 4-(alpha-methylbenzyl)phenol, 2,6-di(alpha-methylbenzyl)phenol, 2,4-di(alpha-methylbenzyl)phenol and 2,4,6-tri(alpha-methylbenzyl)phenol (used as antioxidants), and 2,4-di-tert-butylphenol, which seems to a degradation product of antioxidant. Migration levels of these compounds were 1.68 micrograms/cm2 of 2,4-di-tert-butylphenol, 2.80 micrograms/cm2 of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 46.08 micrograms/cm2 of styrenated phenols and 4.22 micrograms/cm2 of 4,4'-butylidenedi(6-tert-butyl-m-cresol) into n-heptane, respectively. The content of total styrenated phenols was 6,900 micrograms/g in NBR gloves.

Molecular identification and characterization of the pyruvate decarboxylase gene family associated with latex regeneration and stress response in rubber tree.

PubMed

Long, Xiangyu; He, Bin; Wang, Chuang; Fang, Yongjun; Qi, Jiyan; Tang, Chaorong

2015-02-01

In plants, ethanolic fermentation occurs not only under anaerobic conditions but also under aerobic conditions, and involves carbohydrate and energy metabolism. Pyruvate decarboxylase (PDC) is the first and the key enzyme of ethanolic fermentation, which branches off the main glycolytic pathway at pyruvate. Here, four PDC genes were isolated and identified in a rubber tree, and the protein sequences they encode are very similar. The expression patterns of HbPDC4 correlated well with tapping-simulated rubber productivity in virgin rubber trees, indicating it plays an important role in regulating glycometabolism during latex regeneration. HbPDC1, HbPDC2 and HbPDC3 had striking expressional responses in leaves and bark to drought, low temperature and high temperature stresses, indicating that the HbPDC genes are involve in self-protection and defense in response to various abiotic and biotic stresses during rubber tree growth and development. To understand ethanolic fermentation in rubber trees, it will be necessary to perform an in-depth study of the regulatory pathways controlling the HbPDCs in the future. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Mass transfer and benzene removal from air using latex rubber tubing and a hollow-fiber membrane module.

PubMed

Fitch, Mark; Neeman, Jeffrey; England, Ellen

2003-03-01

A dense-phase latex rubber tube and a polyporous propylene hollow-fiber membrane module (HFMM) were investigated for control of benzene-contaminated gas streams. The abiotic mass flux observed through the latex tube was 3.9 13 mg/(min.m(2)) for 150 ppm of benzene at various gas and liquid flow rates, while a 100-fold lower mass flux was observed in the HFMM. After seeding with an aromatic-degrading culture enriched from activated sludge, the observed removal was 80% of 150 ppm, corresponding to a mass flux of 45 mg/(min.m(2)). The observed mass flux through the HFMM during biofiltration also rose, to 0.4 mg/(min.m(2)). Because the HFMM had a 50-fold higher surface area than the latex tube, the observed benzene removal was 99.8%. Compared to conventional biofilters, the two reactors had modest elimination capacities, 2.5 18 g/(m(3).h) in the latex tube membrane bioreactor and 4.8 58 g/(m(3).h) in the HFMM. Although the HFMM had a higher elimination capacity, the gas-phase pressure drop was much greater.

Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuntanoo, K., E-mail: thip-kk@hotmail.com; Promkotra, S., E-mail: sarunya@kku.ac.th; Kaewkannetra, P., E-mail: paknar@kku.ac.th

A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analysesmore » which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (T{sub m}) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.« less

Valorization of guayule as a feedstock for lignocellulosic biorefineries using ammonia fiber expansion (AFEX) pretreatment

USDA-ARS?s Scientific Manuscript database

Natural rubber latex extraction from guayule leaves behind greater than 80% (by weight) of agricultural residue as a feedstock suitable for conversion to biofuels via a thermochemical or biochemical route. Untreated guayule shrub and bagasse (after latex extraction) has shown to be very recalcitrant...

Function of Hevea brasiliensis NAC1 in dehydration-induced laticifer differentiation and latex biosynthesis.

PubMed

Cao, Yuxin; Zhai, Jinling; Wang, Qichao; Yuan, Hongmei; Huang, Xi

2017-01-01

HbNAC1 is a transcription factor in rubber plants whose expression is induced by dehydration, leading to latex biosynthesis. Laticifer is a special tissue in Hevea brasiliensis where natural rubber is biosynthesized and accumulated. In young stems of epicormic shoots, the differentiation of secondary laticifers can be induced by wounding, which can be prevented when the wounding site is wrapped. Using this system, differentially expressed genes were screened by suppression subtractive hybridization (SSH) and macroarray analyses. This led to the identification of several dehydration-related genes that could be involved in laticifer differentiation and/or latex biosynthesis, including a NAC transcription factor (termed as HbNAC1). Tissue sections confirmed that local tissue dehydration was a key signal for laticifer differentiation. HbNAC1 was localized at the nucleus and showed strong transcriptional activity in yeast, suggesting that HbNAC1 is a transcription factor. Furthermore, HbNAC1 was found to bind to the cis-element CACG in the promoter region of the gene encoding the small rubber particle protein (SRPP). Transgenic experiments also confirmed that HbNAC1 interacted with the SRPP promoter when co-expressed, and enhanced expression of the reporter gene β-glucuronidase occurred in planta. In addition, overexpression of HbNAC1 in tobacco plants conferred drought tolerance. Together, the data suggest that HbNAC1 might be involved in dehydration-induced laticifer differentiation and latex biosynthesis.

Laticifer-specific cis-prenyltransferase silencing affects the rubber, triterpene, and inulin content of Taraxacum brevicorniculatum.

PubMed

Post, Janina; van Deenen, Nicole; Fricke, Julia; Kowalski, Natalie; Wurbs, David; Schaller, Hubert; Eisenreich, Wolfgang; Huber, Claudia; Twyman, Richard M; Prüfer, Dirk; Gronover, Christian Schulze

2012-03-01

Certain Taraxacum species, such as Taraxacum koksaghyz and Taraxacum brevicorniculatum, produce large amounts of high-quality natural rubber in their latex, the milky cytoplasm of specialized cells known as laticifers. This high-molecular mass biopolymer consists mainly of poly(cis-1,4-isoprene) and is deposited in rubber particles by particle-bound enzymes that carry out the stereospecific condensation of isopentenyl diphosphate units. The polymer configuration suggests that the chain-elongating enzyme (rubber transferase; EC 2.5.1.20) is a cis-prenyltransferase (CPT). Here, we present a comprehensive analysis of transgenic T. brevicorniculatum plants in which the expression of three recently isolated CPTs known to be associated with rubber particles (TbCPT1 to -3) was heavily depleted by laticifer-specific RNA interference (RNAi). Analysis of the CPT-RNAi plants by nuclear magnetic resonance, size-exclusion chromatography, and gas chromatography-mass spectrometry indicated a significant reduction in rubber biosynthesis and a corresponding 50% increase in the levels of triterpenes and the main storage carbohydrate, inulin. Transmission electron microscopy revealed that the laticifers in CPT-RNAi plants contained fewer and smaller rubber particles than wild-type laticifers. We also observed lower activity of hydroxymethylglutaryl-coenzyme A reductase, the key enzyme in the mevalonate pathway, reflecting homeostatic control of the isopentenyl diphosphate pool. To our knowledge, this is the first in planta demonstration of latex-specific CPT activity in rubber biosynthesis.

High Performance Graphene Oxide Based Rubber Composites

PubMed Central

Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

2013-01-01

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications. PMID:23974435

High performance graphene oxide based rubber composites.

PubMed

Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W; Zhang, Liqun; Liang, Yongri; Liu, Li

2013-01-01

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

The use of smoke acid as an alternative coagulating agent for natural rubber sheets' production.

PubMed

Ferreira, Vanda S; Rêgo, Ione N C; Pastore, Floriano; Mandai, Mariana M; Mendes, Leonardo S; Santos, Karin A M; Rubim, Joel C; Suarez, Paulo A Z

2005-03-01

A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the rubber sheets obtained. This new method of rubber sheet preparation was introduced into Amazonian rainforest rubber tapper communities, which are actually producing in large scale. The physical-mechanical properties were similar among a large sheets made by different rubber tapper communities using this new method.

Statistical inference for classification of RRIM clone series using near IR reflectance properties

NASA Astrophysics Data System (ADS)

Ismail, Faridatul Aima; Madzhi, Nina Korlina; Hashim, Hadzli; Abdullah, Noor Ezan; Khairuzzaman, Noor Aishah; Azmi, Azrie Faris Mohd; Sampian, Ahmad Faiz Mohd; Harun, Muhammad Hafiz

2015-08-01

RRIM clone is a rubber breeding series produced by RRIM (Rubber Research Institute of Malaysia) through "rubber breeding program" to improve latex yield and producing clones attractive to farmers. The objective of this work is to analyse measurement of optical sensing device on latex of selected clone series. The device using transmitting NIR properties and its reflectance is converted in terms of voltage. The obtained reflectance index value via voltage was analyzed using statistical technique in order to find out the discrimination among the clones. From the statistical results using error plots and one-way ANOVA test, there is an overwhelming evidence showing discrimination of RRIM 2002, RRIM 2007 and RRIM 3001 clone series with p value = 0.000. RRIM 2008 cannot be discriminated with RRIM 2014; however both of these groups are distinct from the other clones.

RoxB Is a Novel Type of Rubber Oxygenase That Combines Properties of Rubber Oxygenase RoxA and Latex Clearing Protein (Lcp).

PubMed

Birke, Jakob; Röther, Wolf; Jendrossek, Dieter

2017-07-15

Only two types of rubber oxygenases, rubber oxygenase (RoxA) and latex clearing protein (Lcp), have been described so far. RoxA proteins (RoxAs) are c -type cytochromes of ≈70 kDa produced by Gram-negative rubber-degrading bacteria, and they cleave polyisoprene into 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD), a C 15 oligo-isoprenoid, as the major end product. Lcps are common among Gram-positive rubber degraders and do not share amino acid sequence similarities with RoxAs. Furthermore, Lcps have much smaller molecular masses (≈40 kDa), are b -type cytochromes, and cleave polyisoprene to a mixture of C 20 , C 25 , C 30 , and higher oligo-isoprenoids as end products. In this article, we purified a new type of rubber oxygenase, RoxB Xsp (RoxB of Xanthomonas sp. strain 35Y). RoxB Xsp is distantly related to RoxAs and resembles RoxAs with respect to molecular mass (70.3 kDa for mature protein) and cofactor content (2 c -type hemes). However, RoxB Xsp differs from all currently known RoxAs in having a distinctive product spectrum of C 20 , C 25 , C 30 , and higher oligo-isoprenoids that has been observed only for Lcps so far. Purified RoxB Xsp revealed the highest specific activity of 4.5 U/mg (at 23°C) of all currently known rubber oxygenases and exerts a synergistic effect on the efficiency of polyisoprene cleavage by RoxA Xsp RoxB homologs were identified in several other Gram-negative rubber-degrading species, pointing to a prominent function of RoxB for the biodegradation of rubber in Gram-negative bacteria. IMPORTANCE The enzymatic cleavage of rubber (polyisoprene) is of high environmental importance given that enormous amounts of rubber waste materials are permanently released (e.g., by abrasion of tires). Research from the last decade has discovered rubber oxygenase A, RoxA, and latex clearing protein (Lcp) as being responsible for the primary enzymatic attack on the hydrophobic and water-insoluble biopolymer poly( cis -1,4-isoprene) in Gram-negative and Gram-positive rubber-degrading bacteria, respectively. Here, we provide evidence that a third type of rubber oxygenase is present in Gram-negative rubber-degrading species. Due to its characteristics, we suggest the designation RoxB for the new type of rubber oxygenase. Bioinformatic analysis of genome sequences indicates the presence of roxB homologs in other Gram-negative rubber degraders. Copyright © 2017 American Society for Microbiology.

Effects of habitat management on different feeding guilds of herbivorous insects in cacao agroforestry systems.

PubMed

Novais, Samuel M A; Macedo-Reis, Luiz E; DaRocha, Wesley D; Neves, Frederico S

2016-06-01

Human pressure on natural habitats increases the importance of agroforests for biodiversity conservation. The objective of this study was to evaluate the role of cacao traditional cultivation system (CTCS) on the conservation of the herbivorous insect community when compared with a monodominant rubber agroforest, a type of agricultural system for cacao cultivation. The insects were sampled in three habitats in Southeastern Bahia, Brazil: native forests, CTCS and rubber agroforests. In each habitat, 18 plots of 10 m2 were established, and the structural measures were collected and herbivorous insects were sampled with a Malaise/window trap. The diversity of folivorous decreased with the simplification of vegetation structure, but species composition was similar among habitats. In addition to a decrease in the availability of resources in monodominant rubber agroforests, the latex present in these systems have limited the occurrence of species that cannot circumvent latex toxicity. The diversity of sap-sucking insects was similar among habitats, but species composition was similar only in the CTCS and native forest, and it was different in the rubber agroforest. We observed turnover and a higher frequency of individuals of the family Psyllidae in the rubber agroforest. The biology and behavior of Psyllids and absence of natural enemies enable their diversity to increase when they are adapted to a new host. We observed a shift in the composition of xylophagous insects in the rubber agroforest compared to that in other habitats. Moreover, this agroforest has low species richness, but high individual abundance. Latex extraction is likely an important additional source of volatile compounds discharged into the environment, and it increases the attraction and recruitment of coleoborers to these sites. We concluded that CTCS has an herbivorous insect community with a structure similar to the community found in native forests of the region, and they present a more interesting conservation strategy when compared to rubber agroforests. We also emphasized the potential risk of local pest outbreaks in rubber agroforests for both the rubber and associated cacao trees.

Studies of the latex of Brazilian IAC series clones from Hevea brasiliensis

USDA-ARS?s Scientific Manuscript database

Natural rubber is an important commodity industrial crop that mainly derives from Hevea brasiliensis. Most natural rubber production is in Southeast Asia, but significant cultivar development takes place in Brazil, the original origin of current commercial H. brasiliensis cultivars. Thus it is criti...

Energy-dense liquid fuel intermediates by pyrolysis of guayule (Parthenium argentatum) shrub and bagasse

USDA-ARS?s Scientific Manuscript database

Guayule is a perennial shrub grown in the southwestern United States that is used to produce high quality, natural rubber latex. However, only about 10% of the plant material is used for latex production; the remaining biomass, called bagasse, can be used for renewable fuel production. Fast pyroly...

Interior. Apparatus used in crushing and processing plant fibers to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Apparatus used in crushing and processing plant fibers to extract latex from the sap during experiments to find native North American plant which would yield sufficiently high percentage of latex to produce natural rubber. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Occult glove perforation during ophthalmic surgery.

PubMed Central

Apt, L; Miller, K M

1992-01-01

We examined the latex surgical gloves used by 56 primary surgeons in 454 ophthalmic surgical procedures performed over a 7-month period. Of five techniques used to detect pinholes, air inflation with water submersion and compression was found to be the most sensitive, yielding a 6.80% prevalence in control glove pairs and a 21.8% prevalence in postoperative study glove pairs, for a 15.0% incidence of surgically induced perforations (P = 0.000459). The lowest postoperative perforation rate was 11.4% for cataract and intraocular lens surgery, and the highest was 41.7% for oculoplastic procedures. Factors that correlated significantly with the presence of glove perforations as determined by multiple logistic regression analysis were oculoplastic and pediatric ophthalmology and strabismus surgical procedures, surgeon's status as a fellow in training, operating time, and glove size. The thumb and index finger of the nondominant hand contained the largest numbers of pinholes. These data suggest strategies for reducing the risk of cross-infection during ophthalmic surgery. PMID:1494836

Variability in surface infrared reflectance of thirteen nitrile rubber gloves at key wavelengths for analysis of captan.

PubMed

Phalen, R N; Que Hee, Shane S

2007-02-01

The aim of this study was to investigate the surface variability of 13 powder-free, unlined, and unsupported nitrile rubber gloves using attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectrophotometry at key wavelengths for analysis of captan contamination. The within-glove, within-lot, and between-lot variability was measured at 740, 1124, 1252, and 1735 cm(-1), the characteristic captan reflectance minima wavelengths. Three glove brands were assessed after conditioning overnight at relative humidity (RH) values ranging from 2 +/- 1 to 87 +/- 4% and temperatures ranging from -8.6 +/- 0.7 to 59.2 +/- 0.9 degrees C. For all gloves, 1735 cm(-1) provided the lowest background absorbance and greatest potential sensitivity for captan analysis on the outer glove surface: absorbances ranged from 0.0074 +/- 0.0005 (Microflex) to 0.0195 +/- 0.0024 (SafeSkin); average within-glove coefficients of variation (CV) ranged from 2.7% (Best, range 0.9-5.3%) to 10% (SafeSkin, 1.2-17%); within-glove CVs greater than 10% were for one brand (SafeSkin); within-lot CVs ranged from 2.8% (Best N-Dex) to 28% (SafeSkin Blue); and between-lot variation was statistically significant (p < or = 0.05) for all but two SafeSkin lots. The RH had variable effects dependent on wavelength, being minimal at 1735, 1252, and 1124 cm(-1) and highest at 3430 cm(-1) (O-H stretch region). There was no significant effect of temperature conditioning. Substantial within-glove, within-lot, and between-lot variability was observed. Thus, surface analysis using ATR-FT-IR must treat glove brands and lots as different. ATR-FT-IR proved to be a useful real-time analytical tool for measuring glove variability, detecting surface humidity effects, and choosing selective and sensitive wavelengths for analysis of nonvolatile surface contaminants.

Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis

NASA Astrophysics Data System (ADS)

Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D.; Baffa, Oswaldo

2011-11-01

Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO 3 contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO 3 concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

Analysis of the usage of rubberized asphalt in hot mix asphalt using Reclaimed Asphalt Pavement (RAP)

NASA Astrophysics Data System (ADS)

Dwidarma Nataadmadja, Adelia; Prahara, Eduardi; Sumbung, Pierre Christian

2017-12-01

There has been an increasing demand in using more environmentally friendly materials in pavement construction. One of the alternative materials that have been widely used is the Reclaimed Asphalt Pavement (RAP) aggregates. The RAP aggregates are derived from the crushed and screened pavement materials that contain asphalt and aggregates. This material is usually combined with natural aggregates and virgin asphalt binder to construct a new pavement. There have been numerous positive feedbacks in using this material although RAP aggregates also have certain weaknesses, such as questionable interaction between virgin and recycled materials and increased stiffness of RAP binder. Moreover, there has been a push on using rubber as an additive to asphalt binder to improve the welfare of rubber farmers. This research combines the usage of both latex and RAP as the ingredients to design hot mix asphalt (HMA) as latex could help in improving the flexibility of HMA and the interaction between the virgin and recycled materials. The main objective of this research is to find a suitable percentage of RAP aggregates to be used in HMA with certain percentage of latex as the binder additive.

Glove box shield

DOEpatents

Brackenbush, Larry W.; Hoenes, Glenn R.

1981-01-01

According to the present invention, a shield for a glove box housing radioactive material is comprised of spaced apart clamping members which maintain three overlapping flaps in place therebetween. There is a central flap and two side flaps, the side flaps overlapping at the interior edges thereof and the central flap extending past the intersection of the side flaps in order to insure that the shield is always closed when the user withdraws his hand from the glove box. Lead loaded neoprene rubber is the preferred material for the three flaps, the extent of lead loading depending upon the radiation levels within the glove box.

HIGH-PERFORMANCE STEREOSPECIFIC ELASTOMERS FROM BIOREACTORS

USDA-ARS?s Scientific Manuscript database

In 2008, 10 million tons of natural rubber, cis-1,4-polyisoprene, will be produced for commercial use. Every molecule of that product will be produced in a microscopic bioreactor known as the rubber particle. These particles, suspended in an aqueous phase called latex, evolved to produce and store n...

Allergy and desensitization to latex. Clinical study on 50 dentistry subjects.

PubMed

Vozza, I; Ranghi, G; Quaranta, A

2005-04-01

Nowadays latex allergy represents a relevant social and occupational problem because this substance constitutes the first material to realise many dental and non dental products; then, there is a cross-reactivity between latex allergens and proteins present in many vegetal foods. The aim of our research was to find latex allergy cases experimenting a percutaneous desensitization protocol. Among 50 examined subjects, those patients resulting positive to thiuram-mix by patch test have been submitted to desensitization after removal of all latex products and substances giving cross-allergy (kiwi, celery, chestnuts, tomato, banana etc.). Desensitization has been carried out by using latex glove from 10 s progressively to 1 h after 1-year treatment. In 7 patients out of 11 (63.6%) regression of symptoms has been verified; 2 patients (18.2%) have declined treatment and 2 patients (18.2%) have showed no regression. Apart immunotherapy and DNA-vaccines, nowadays percutaneous desensitization is the most efficacious, safe and easy treatment for latex allergic patients; it has no collateral effects during its execution and no symptoms coming back to work, but it needs further verifications.

Enhancing mechanical and thermal properties of styrene-butadiene rubber/carboxylated acrylonitrile butadiene rubber blend by the usage of graphene oxide with diverse oxidation degrees

NASA Astrophysics Data System (ADS)

Xue, Xiaodong; Yin, Qing; Jia, Hongbing; Zhang, Xuming; Wen, Yanwei; Ji, Qingmin; Xu, Zhaodong

2017-11-01

Graphene oxide (GO) with various oxidation degrees were prepared through a modified Hummer's method by varying the dosage of oxidizing agent. Styrene-butadiene rubber (SBR)/carboxylated acrylonitrile butadiene rubber (XNBR)/GO nanocomposites were fabricated by aqueous-phase mixing of GO colloidal dispersion with SBR latex and a small loading of XNBR latex, followed by co-coagulation. Effects of GO oxidation degree on the morphology, structure, mechanical and thermal properties of nanocomposites were thoroughly investigated. The results showed that the mechanical strength of nanocomposites were enhanced with the increase of oxidation degree of GO. Especially, when the weight ratio of KMnO4 to graphite was 15/5, the tensile strength, tear strength and thermal conductivity of SBR/XNBR/GO filled with 3 phr (parts per hundred rubber) GO increased by 255.3%, 141.5% and 22.8%, respectively, compared to those of neat SBR/XNBR blend. In addition, the thermal stability and the solvent resistance of the nanocomposites were also improved significantly. This work suggested that GO with higher oxidation degree could effectively improve the properties of SBR/XNBR blend.

Anatomical and functional evaluation of tympanoplasty using a transitory natural latex biomembrane implant from the rubber tree Hevea brasiliensis.

PubMed

Araujo, Marcos Miranda; Massuda, Eduardo Tanaka; Hyppolito, Miguel Angelo

2012-08-01

To compare the role of transitory latex and sylastic® implants in tympanoplasty on the closure of tympanic perforations. A randomized double-blind prospective study was conducted on 107 patients with chronic otitis media submitted to underlay tympanoplasty and divided at random into three groups: control with no transitory implant, latex membrane group, and sylastic® membrane group. Greater graft vascularization occurred in the latex membrane group (p<0.05). Good biocompatibility was obtained with the use of the latex and silicone implants, with no effect on the occurrence of infection, otorrhea or otorragy. The use of a transitory latex implant induced greater graft vascularization, with a biocompatible interaction with the tissue of the human tympanic membrane.

Laticifer-Specific cis-Prenyltransferase Silencing Affects the Rubber, Triterpene, and Inulin Content of Taraxacum brevicorniculatum12[C][W

PubMed Central

Post, Janina; van Deenen, Nicole; Fricke, Julia; Kowalski, Natalie; Wurbs, David; Schaller, Hubert; Eisenreich, Wolfgang; Huber, Claudia; Twyman, Richard M.; Prüfer, Dirk; Gronover, Christian Schulze

2012-01-01

Certain Taraxacum species, such as Taraxacum koksaghyz and Taraxacum brevicorniculatum, produce large amounts of high-quality natural rubber in their latex, the milky cytoplasm of specialized cells known as laticifers. This high-molecular mass biopolymer consists mainly of poly(cis-1,4-isoprene) and is deposited in rubber particles by particle-bound enzymes that carry out the stereospecific condensation of isopentenyl diphosphate units. The polymer configuration suggests that the chain-elongating enzyme (rubber transferase; EC 2.5.1.20) is a cis-prenyltransferase (CPT). Here, we present a comprehensive analysis of transgenic T. brevicorniculatum plants in which the expression of three recently isolated CPTs known to be associated with rubber particles (TbCPT1 to -3) was heavily depleted by laticifer-specific RNA interference (RNAi). Analysis of the CPT-RNAi plants by nuclear magnetic resonance, size-exclusion chromatography, and gas chromatography-mass spectrometry indicated a significant reduction in rubber biosynthesis and a corresponding 50% increase in the levels of triterpenes and the main storage carbohydrate, inulin. Transmission electron microscopy revealed that the laticifers in CPT-RNAi plants contained fewer and smaller rubber particles than wild-type laticifers. We also observed lower activity of hydroxymethylglutaryl-coenzyme A reductase, the key enzyme in the mevalonate pathway, reflecting homeostatic control of the isopentenyl diphosphate pool. To our knowledge, this is the first in planta demonstration of latex-specific CPT activity in rubber biosynthesis. PMID:22238421

A Lettuce (Lactuca sativa) Homolog of Human Nogo-B Receptor Interacts with cis-Prenyltransferase and Is Necessary for Natural Rubber Biosynthesis*

PubMed Central

Qu, Yang; Chakrabarty, Romit; Tran, Hue T.; Kwon, Eun-Joo G.; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

2015-01-01

Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3–15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro. PMID:25477521

A lettuce (Lactuca sativa) homolog of human Nogo-B receptor interacts with cis-prenyltransferase and is necessary for natural rubber biosynthesis.

PubMed

Qu, Yang; Chakrabarty, Romit; Tran, Hue T; Kwon, Eun-Joo G; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

2015-01-23

Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3-15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Design and characterization of low-cost fabric-based flat pneumatic actuators for soft assistive glove application.

PubMed

Yap, Hong Kai; Sebastian, Frederick; Wiedeman, Christopher; Yeow, Chen-Hua

2017-07-01

We present the design of low-cost fabric-based Hat pneumatic actuators for soft assistive glove application. The soft assistive glove is designed to assist hand impaired patients in performing activities of daily living and rehabilitation. The actuators consist of flexible materials such as fabric and latex bladder. Using zero volume actuation concept, the 2D configuration of the actuators simplifies the manufacturing process and allows the actuators to be more compact. The actuators achieve bi-directional flexion and extension motions. Compared to previously developed inflatable soft actuators, the actuators generate sufficient force and torque to assist in both finger flexion and extension at lower air pressure. Preliminary evaluation results show that the glove is able to provide both active finger flexion and extension assistance for activities of daily living and rehabilitative training.

Identification of three homologous latex-clearing protein (lcp) genes from the genome of Streptomyces sp. strain CFMR 7.

PubMed

Nanthini, Jayaram; Ong, Su Yean; Sudesh, Kumar

2017-09-10

Rubber materials have greatly contributed to human civilization. However, being a polymeric material does not decompose easily, it has caused huge environmental problems. On the other hand, only few bacteria are known to degrade rubber, with studies pertaining them being intensively focusing on the mechanism involved in microbial rubber degradation. The Streptomyces sp. strain CFMR 7, which was previously confirmed to possess rubber-degrading ability, was subjected to whole genome sequencing using the single molecule sequencing technology of the PacBio® RS II system. The genome was further analyzed and compared with previously reported rubber-degrading bacteria in order to identify the potential genes involved in rubber degradation. This led to the interesting discovery of three homologues of latex-clearing protein (Lcp) on the chromosome of this strain, which are probably responsible for rubber degrading activities. Genes encoding oxidoreductase α-subunit (oxiA) and oxidoreductase β-subunit (oxiB) were also found downstream of two lcp genes which are located adjacent to each other. In silico analysis reveals genes that have been identified to be involved in the microbial degradation of rubber in the Streptomyces sp. strain CFMR 7. This is the first whole genome sequence of a clear-zone-forming natural rubber- degrading Streptomyces sp., which harbours three Lcp homologous genes with the presence of oxiA and oxiB genes compared to the previously reported Gordonia polyisoprenivorans strain VH2 (with two Lcp homologous genes) and Nocardia nova SH22a (with only one Lcp gene). Copyright © 2017 Elsevier B.V. All rights reserved.

Gasoline on hands: preliminary study on collection and persistence.

PubMed

Darrer, Melinda; Jacquemet-Papilloud, Joëlle; Delémont, Olivier

2008-03-05

The identification of an arsonist remains one of the most difficult challenges a fire investigation has to face. Seeking and detection of traces of gasoline could provide a valuable information to link a suspect with an arson scene where gasoline was used to set-up the fire. In this perspective, a first study was undertaken to evaluate a simple, fast and efficient method for collecting gasoline from hands, and to assess its persistence over time. Four collection means were tested: PVC, PE and Latex gloves, as well as humidified filter paper. A statistical assessment of the results indicates that Latex and PVC gloves worn for about 20 min, as well as paper filter rubbed on hands, allow an efficient collection of gasoline applied to hands. Due to ease of manipulation and to a reduced amount of volatile compounds detected from the matrix, PVC gloves were selected for the second set of experiments. The evaluation of the persistence of gasoline on hands was then carried out using two initial quantities (500 and 1000 microl). Collection was made with PVC gloves after 0, 30 min, 1, 2 and 4h, on different volunteers. The results show a common tendency of massive evaporation of gasoline during the first 30 min: a continued but non-linear decrease was observed along different time intervals. The results of this preliminary study are in agreement with other previous researches conducted on the detection of flammable liquid residues on clothes, shoes and skin.

Skin reactions amongst Greek endodontists: a national questionnaire survey.

PubMed

Zarra, T; Lambrianidis, T

2015-04-01

To investigate amongst Greek endodontists in the past 5 years the prevalence, aetiologic factors, severity and treatment for skin reactions. One hundred and 47 endodontists met the inclusion criteria and were invited to participate in the survey. Participants were asked for personal/professional data, prevalence, aetiologic factors, symptoms, severity and treatment for skin reactions in the past 5 years. The type of gloves used and frequency of hand washing as well as information on history of atopy and eczema were also recorded. Data were analysed using chi-square test and independent samples t-test. The level of significance was set at P = 0.05. The response rate was 84%. Skin reactions were reported by 32.5% of participants. Hands were the body part most frequently affected (66% of cases); glove powder accounted for 73% of skin reactions. Medical care was sought by 28.2% of the affected participants. Endodontists with a history of atopy (P < 0.001) and dermal eczema (P < 0.001) as well as females (P = 0.023) were more likely to report skin reactions. Replacement of powdered latex gloves with powder-free or vinyl/nitrile gloves, avoidance of potential allergens and use of pharmaceutical ointments were adopted by 48.7%, 23.1% and 2.6% of the affected endodontists, respectively, to manage skin reactions. Approximately one-third of participants reported skin reactions. History of atopy and dermal eczema as well as gender was significantly associated with such reactions. The use of powder-free latex gloves instead of powdered ones was the measure most frequently adopted to manage reactions. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Analysis of algal chlorophylls and carotenoids

NASA Astrophysics Data System (ADS)

Bidigare, Robert R.

Water samples should be collected with Go-Flo bottles to avoid the contamination problems associated with the latex rubber closure mechanism of Niskin bottles [Williams and Robertson, 1989]. Price et al. [1986] have documented that latex rubber is extremely toxic to marine phytoplankton. It is recommended that only silicone tubing be used to dispense seawater into sample bottles. Seawater is dispensed into opaque Nalgene sample bottles to avoid light shock to deep-living phytoplankton assemblages. If pigment samples are collected to examine the dynamics of the diatoxanthin-diadinoxanthin (DT-DN) xanthophyll cycle, then casts should be performed quickly, i.e. less than 6 minutes, to minimize DT-DN interconversion prior to filtration [Welschmeyer and Hoepffner, in press; Welschmeyer, personal communication, 1990].

Antifungal activity of fluconazole-loaded natural rubber latex against Candida albicans.

PubMed

Yonashiro Marcelino, Mônica; Azevedo Borges, Felipe; Martins Costa, Ana Flávia; de Lacorte Singulani, Junya; Ribeiro, Nathan Vinícius; Barcelos Costa-Orlandi, Caroline; Garms, Bruna Cambraia; Soares Mendes-Giannini, Maria José; Herculano, Rondinelli Donizetti; Fusco-Almeida, Ana Marisa

2018-03-01

This work aimed to produce a membrane based on fluconazole-loaded natural rubber latex (NRL), and study their interaction, drug release and antifungal susceptibility against Candida albicans. Fluconazole-loaded NRL membrane was obtained by casting method. The Fourier Transform Infrared Spectroscopy showed no modifications either in NRL or fluconazole after the incorporation. Mechanical test presented low Young's modulus and high strain, indicating the membranes have sufficient elasticity for biomedical application. The bio-membrane was able to release the drug and inhibit the growth of C. albicans as demonstrated by disk diffusion and macrodilution assays. The biomembrane was able to release fluconazole and inhibit the growth of C. albicans, representing a promising biomaterial for skin application.

Microgravity Science Glovebox - Glove

NASA Technical Reports Server (NTRS)

1997-01-01

This photo shows a rubber glove and its attachment ring for the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

In-depth survey report: control technology assessment of unit operations employed in oral-contraceptive tablet-making operations at Ortho Pharmaceutical Corporation, Raritan, New Jersey, June 13-17, 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastas, M.Y.; Caplan, P.E.; Froehlich, P.A.

An on-site visit was made to the Ortho Pharmaceutical Corporation (OPC), Raritan, New Jersey to evaluate methods of controlling exposure to hazardous materials during the manufacturing of medications. OPC produced oral-contraceptive tablets containing norethindrone (NOR), mestranol, and ethynylestradiol (EE). Ventilation was an important engineering control at this site. Other engineering controls included the isolation of work procedures and automation of work practices for weighing ingredients, granulation of substances, tableting, and packaging. Area samples were taken for air monitoring of steroid concentration levels in each manufacturing area. Access to the work areas was only through the locker rooms. Samples taken inmore » the locker rooms revealed no detectable contaminant levels. Workers performing high risk activities wore air supplied vinyl suits and disposable rubber gloves. The vinyl suits had overshoes attached. For moderate risk activities the workers wore a disposable suit, rubber gloves and shoe covers. Appropriate respirators were provided. Workers in low risk activities wore disposable rubber gloves and appropriate respirators. Sampling indicated that processing workers experienced breathing-zone levels outside their vinyl suits of 16.40 and 0.36 micrograms/cubic meter of NOR and EE, respectively.« less

Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis.

PubMed

Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D; Baffa, Oswaldo

2011-11-01

Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO(3) contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO(3) concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive. Copyright © 2011 Elsevier B.V. All rights reserved.

Reinforcement of natural rubber latex using lignocellulosic nanofibers isolated from spinifex grass.

PubMed

Hosseinmardi, Alireza; Annamalai, Pratheep K; Wang, Lianzhou; Martin, Darren; Amiralian, Nasim

2017-07-13

Reinforcement of natural rubber (NR) using nanofillers often results in an enhancement of the tensile strength, but at the expense of elongation at break and toughness. In this study, with the objective of strengthening NR without compromising its compliance, we investigate the reinforcement efficiency of a series of cellulose nanofibers (CNF) with variations in residual hemicellulose, lignin and therefore surface chemistry. Different types of high aspect ratio CNF isolated from Triodia pungens (T. pungens), an Australian arid grass commonly known as spinifex, were added at 0.1-2 wt% loadings into a pre-vulcanized NR latex. CNF/NR nanocomposites then were benchmarked against NR nanocomposites incorporating a well-known wood-derived CNF. It was found that the presence of residual lignin and hemicellulose, and the pretreatment with a deep eutectic solvent, a mixture of choline chloride and urea (CCU), could increase the compatibility of CNF with the NR matrix, while still enabling stability and handling of the colloidal latex mixture. Incorporation of 0.5 and 0.1 wt% of the sodium hydroxide treated CNF and choline chloride/urea treated CNF into the NR latex showed respectively 11 and 17% enhancement in tensile stress, and importantly without compromising viscoelastic properties; while addition of 0.1 wt% wood-derived CNF resulted in 18% decrease in both tensile stress and strain coupled with more pronounced latex stiffening.

Historical and Recent Achievements in the Field of Microbial Degradation of Natural and Synthetic Rubber

PubMed Central

Yikmis, Meral

2012-01-01

This review intends to provide an overview of historical and recent achievements in studies of microbial degradation of natural and synthetic rubber. The main scientific focus is on the key enzymes latex-clearing protein (Lcp) from the Gram-positive Streptomyces sp. strain K30 and rubber oxygenase A (RoxA) from the Gram-negative Xanthomonas sp. strain 35Y, which has been hitherto the only known rubber-degrading bacterium that does not belong to the actinomycetes. We also emphasize the importance of knowledge of biodegradation in industrial and environmental biotechnology for waste natural rubber disposal. PMID:22504822

49 CFR 372.115 - Commodities that are not exempt under 49 U.S.C. 13506(a)(6).

Code of Federal Regulations, 2012 CFR

2012-10-01

... extracted from grain Popcorn, popped Rice, precooked Wheat germ Gravel Hair, hog or other animal, product of... Pulp, sugar cane Rock (except natural crushed, vesicular rock to be used for decorative purposes) Rubber, crude, in bales Rubber, latex, natural, liquid, from which water has been extracted and to which...

49 CFR 372.115 - Commodities that are not exempt under 49 U.S.C. 13506(a)(6).

Code of Federal Regulations, 2014 CFR

2014-10-01

... extracted from grain Popcorn, popped Rice, precooked Wheat germ Gravel Hair, hog or other animal, product of... Pulp, sugar cane Rock (except natural crushed, vesicular rock to be used for decorative purposes) Rubber, crude, in bales Rubber, latex, natural, liquid, from which water has been extracted and to which...

49 CFR 372.115 - Commodities that are not exempt under 49 U.S.C. 13506(a)(6).

Code of Federal Regulations, 2013 CFR

2013-10-01

... extracted from grain Popcorn, popped Rice, precooked Wheat germ Gravel Hair, hog or other animal, product of... Pulp, sugar cane Rock (except natural crushed, vesicular rock to be used for decorative purposes) Rubber, crude, in bales Rubber, latex, natural, liquid, from which water has been extracted and to which...

49 CFR 372.115 - Commodities that are not exempt under 49 U.S.C. 13506(a)(6).

Code of Federal Regulations, 2011 CFR

2011-10-01

... extracted from grain Popcorn, popped Rice, precooked Wheat germ Gravel Hair, hog or other animal, product of... Pulp, sugar cane Rock (except natural crushed, vesicular rock to be used for decorative purposes) Rubber, crude, in bales Rubber, latex, natural, liquid, from which water has been extracted and to which...

Teaching suturing in a workshop setting: a comparison of several models.

PubMed

Tokuhara, Keith G; Boldt, David W; Yamamoto, Loren G

2004-09-01

Suturing is taught in workshops using a variety of models. The purpose of this study is to compare the resemblance to human skin of four models commonly used to teach suturing: pig skin, beef tongue, hot dog and latex glove. 5 centimeter biconvex incisions were made in each of the models and closed by 50 physician study volunteers comprised of 33 board-certified physicians and 17 resident physicians. They rated each model on a scale of 1 to 4, where 4 closely resembles human skin and 1 does not resemble human skin. The following mean ratings were given by study volunteers: beef tongue 3.5 +/- 0.5, pig skin 3.2 +/- 0.8, latex glove 1.6 +/- 0.7, hot dog 1.4 +/- 0.6. Beef tongue and pig skin were rated highest by study volunteers. However, pig skin is much cheaper than beef tongue. Pig skin is the best inexpensive model for teaching skin suturing of the four models studied.

Association of contact urticaria and allergic contact dermatitis to rubber.

PubMed

Fernadez, Ohalis Luanda; Canosa, Juliana Macedo; Lazzarini, Rosana; Duarte, Ida

2009-01-01

We present a case of a healthcare professional that developed type I and IV hypersensitivity reactions to rubber. During the clinical examination the patient showed eczematous dermatitis of the hands. The patch test was positive for thiuram group and an open test with a piece of glove was positive after 20 minutes of exposure. Allergen-specific IgE test (RAST) was relevant. Reactions to rubber allergens are frequent among healthcare professionals due to constant contact with this material.

Preliminary study of semi-refined carrageenan (SRC) as secondary gelling agent in natural rubber (NR) latex foam

NASA Astrophysics Data System (ADS)

Norhazariah, S.; Azura, A. R.; Azahari, B.; Sivakumar, R.

2017-12-01

Semi-refined carrageenan (SRC) product is considerably cheaper and easier to produce as a natural polysaccharide, which was utilized in food and other product application. However, the application in latex is limited. The aim of this work is to evaluate the SRC produced from low industrial grade seaweed (LIGS) in the latex foam application. The FTIR spectra showed the SRC produced as kappa type carrageenan with lower sulfur content compared to native LIGS. NR latex foam is produced by using the Dunlop method with some modifications. The effect of SRC loading as a secondary gelling agent in NR latex foam is investigated. The density and morphology of the NR latex foam with the addition of the SRC are analyzed. NR latex foam density increased with SRC loading and peaked at 1.8 phr SRC. The addition of SRC has induced the bigger cell size compared to the cell size of the control NR latex foam, as shown in the optical micrograph. It can be concluded that SRC LIGS could be acted as secondary gelling agent in NR latex foam.

Physics-Based Modeling of Permeation: Simulation of Low-Volatility Agent Permeation and Aerosol Vapor Liquid Assessment Group Experiments

DTIC Science & Technology

2015-06-01

methylphosphonothiolate (VX) through natural latex rubber and neoprene resulting from LVAP tests. 2. The permeation model is used to study the sensitivity of...Styrene–Butadiene– Rubber , Ethylene–Propylene–Diene Terpolymer, and Natural Rubber Versus Hydrocarbons (C8–C16). Macromolecules 1991, 24 (9), 2598–2605...22 14. Harogoppad, S.B.; Aminabhavi, T.M. Diffusion and Sorption of Organic Liquids through Polymer Membranes 2. Neoprene, SBR, EPDM , NBR, and

29 CFR 1926.551 - Helicopters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and mechanically. (e) Personal protective equipment. (1) Personal protective equipment for employees... the suspended load, or protective rubber gloves shall be worn by all ground personnel touching the...

29 CFR 1926.551 - Helicopters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and mechanically. (e) Personal protective equipment. (1) Personal protective equipment for employees... the suspended load, or protective rubber gloves shall be worn by all ground personnel touching the...

Natural rubber (NR) biosynthesis: perspectives from polymer chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barkakaty, Balaka

Natural rubber is an important strategic raw material for manufacturing a wide variety of industrial products. There are at least 2,500 different latex-producing plant species; however, only Hevea brasiliensis (the Brazilian rubber tree) is a commercial source. The chemical structure of natural rubber is cis-1,4-polyisoprene, but the exact structure of the head and end groups remains unknown. Since synthetic cis-1,4-polyisoprenes cannot match the superior properties of natural rubber, understanding the chemistry behind the biosynthetic process is key to finding a possible replacement. T his chapter summarizes our current understandings from the perspective of a polymer scientist by comparing synthetic polyisoprenesmore » to natural rubber. The chapter also highlights biomimetic polymerization, research towards a synthetic match of natural rubber and the role of natural rubber in health care.« less

New York inmates' HIV risk behaviors: the implications for prevention policy and programs.

PubMed

Mahon, N

1996-09-01

The median incidence rate of acquired immunodeficiency syndrome (AIDS) among prisoners is 7 times higher than for the general population. Yet high-risk sexual activity and drug use in US correctional facilities remain unexamined. This study explores inmate perceptions of high-risk behavior in New York state prisons and New York City jails and seeks to generate hypotheses to inform policies and future research. Participants were 22 former New York state prisoners and 28 current New York City inmates. Participants attended one of six focus groups and completed an anonymous questionnaire. Audiotapes of the groups were transcribed and evaluated. A range of consensual and nonconsensual sexual activity occurs among inmates and between inmates and staff. Without official access to latex barriers, prisoners use ineffective makeshift devices, like rubber gloves and used plastic wrap, in attempts to practice safer sex. Prisoners also shoot drugs intravenously with used syringes and pieces of pens and light bulbs. The absence of harm-reduction devices behind bars may create a greater risk of HIV transmission there than in the community. Officials should consider distributing risk-reduction devices to prisoners through anonymous methods.

Rubber particle proteins, HbREF and HbSRPP, show different interactions with model membranes.

PubMed

Berthelot, Karine; Lecomte, Sophie; Estevez, Yannick; Zhendre, Vanessa; Henry, Sarah; Thévenot, Julie; Dufourc, Erick J; Alves, Isabel D; Peruch, Frédéric

2014-01-01

The biomembrane surrounding rubber particles from the hevea latex is well known for its content of numerous allergen proteins. HbREF (Hevb1) and HbSRPP (Hevb3) are major components, linked on rubber particles, and they have been shown to be involved in rubber synthesis or quality (mass regulation), but their exact function is still to be determined. In this study we highlighted the different modes of interactions of both recombinant proteins with various membrane models (lipid monolayers, liposomes or supported bilayers, and multilamellar vesicles) to mimic the latex particle membrane. We combined various biophysical methods (polarization-modulation-infrared reflection-adsorption spectroscopy (PM-IRRAS)/ellipsometry, attenuated-total reflectance Fourier-transform infrared (ATR-FTIR), solid-state nuclear magnetic resonance (NMR), plasmon waveguide resonance (PWR), fluorescence spectroscopy) to elucidate their interactions. Small rubber particle protein (SRPP) shows less affinity than rubber elongation factor (REF) for the membranes but displays a kind of "covering" effect on the lipid headgroups without disturbing the membrane integrity. Its structure is conserved in the presence of lipids. Contrarily, REF demonstrates higher membrane affinity with changes in its aggregation properties, the amyloid nature of REF, which we previously reported, is not favored in the presence of lipids. REF binds and inserts into membranes. The membrane integrity is highly perturbed, and we suspect that REF is even able to remove lipids from the membrane leading to the formation of mixed micelles. These two homologous proteins show affinity to all membrane models tested but neatly differ in their interacting features. This could imply differential roles on the surface of rubber particles. © 2013.

Hydroxyapatite moldable formulation using natural rubber latex as binder.

PubMed

Sailaja, G S; Ramesh, P; Varma, H K

2007-07-01

A simple but efficient processing method for shaping intricate bioceramic green bodies has been developed by using natural rubber latex as binder. Different shapes of hydroxyapatite Ca10(PO4)6(OH)2 (HAP) were molded from a composite formulation containing wet precipitated HAP, natural rubber latex (NRL), and a stabilizer. On controlled heat treatment followed by sintering, dense shapes of HAP contours were obtained. The thermal degradation profile of HAP-NRL composites shows that NRL degrades slowly without any abrupt exotherm. The results of energy dispersive X-ray analysis together with inductively coupled plasma (ICP) analysis indicate that the inorganic residue of NRL does not contain any heavy element. The sintered density of the samples increased with increased HAP content in the formulation and percentage shrinkage reduced accordingly. On varying the HAP content in the formulation from 35 to 95 wt %, the compositions with 85, 90, 92, and 95 wt % HAP showed better flexural strength in the range 40-54 MPa and a flexural modulus value in the range 36-50 GPa. The fracture morphology, as observed by the scanning electron microscope confirms that with increased HAP content in the formulation the sample microstructure attains higher uniformity. The Vickers microhardness for the samples sintered at two different temperatures (1150 and 1250 degrees C) showed that hardness increases with increase in the sintering temperature with a maximum for the highest HAP loaded formulation. Copyright 2006 Wiley Periodicals, Inc.

[Changes in the peripheral blood of workers engaged in ethylbenzene-styrene and synthetic rubber and latex manufacture].

PubMed

Khristeva, V

1986-01-01

A total of 67 workers were examined from the production of "Ethyl benzene-styrene" and 184 workers from the production of "Synthetic rubber and latex", as well as a control group of 59 employees. The workers from the first production are exposed to the effect of styrene, ethyl benzene and toluene. The concentrations of the substances surpass MAC, with several times, at the majority of the working places. The workers with a length of service over 10 years predominate. The workers from the second production are exposed to the combined effect of styrene and divinyl, their concentrations fluctuating from 2 to 8 times over MAC. The workers with a length of service over 10 years are 71.7%. The deviations, established in the hematological indices studied are compared with the results from a study on the workers from those productions of 6 years ago. Dynamics in the changes was established among the workers from the production of "Synthetic rubber and latex", associated with the duration of occupational exposure to styrene and divinyl. In case of a shorter length of service, the deviations are functional (reduction of peroxidase activity in granulocytes), increase of hemoglobin and hematocrit, associated with the adaptive reaction of organism. Pronounced anemic syndrome was established in a considerable number (24 workers) after an exposure of 10 years as well as lymphocytosis (35 subjects) and leukopenia (9 subjects).

Unexpected source of latex sensitization in a neonatal intensive care unit.

PubMed

Wynn, R J; Boneberg, A; Lakshminrusimha, S

2007-09-01

We report a term infant with gastroschisis who presented with a systemic allergic reaction at a specific time of each day coinciding with infusion from a new preparation of total parenteral nutrition and intravenous lipid emulsion. The source of latex was traced to the rubber stopper of the lipid emulsion. We present this case to highlight the possibility of allergy from this unexpected source in a neonate.

Biocompatibility studies of natural rubber latex from different tree clones and collection methods.

PubMed

Floriano, Juliana Ferreira; da Mota, Lígia Souza Lima Silveira; Furtado, Edson Luiz; Rossetto, Victor José Vieira; Graeff, Carlos F O

2014-02-01

Natural rubber latex (NRL) has several features that make it an excellent biomaterial to promote the growth and repair of tissues, skin and bones. Most of the research with NRL membranes uses a mixture of different clones and chemical preservatives in the collection process. In this study, we compared five clones that produce NRL, seeking to identify their differences in biocompatibility. The clones studied were RRIM 600, PB 235, GT1, PR 255 and IAN 873 commonly found in plantations in Brazil. We did also study the effect of ammonia used during latex collection. NRL membranes were prepared aseptically and sterilized. In the in vitro tests, the membranes remained in direct contact with mouse fibroblasts cells for three periods, 24, 48 and 72 h. In the in vivo tests, the membranes were implanted subcutaneously in rabbits. The results indicated the biocompatibility of the membranes obtained from all clones. Membranes from the clones RRIM 600 and IAN 873 induced greater cell proliferation, suggesting greater bioactivity. It was found that the membranes made from latex that was in contact with ammonia during collection, showed cytotoxic and genotoxic effects in cultures, as well as necrosis, and increased inflammatory cells in the rabbit's tissues close to the implant.

Grafting poly(vinyl alcohol) onto polybutadiene rubber latex particles by pre-irradiation

NASA Astrophysics Data System (ADS)

Tian, Bo; Dong, Wei; Liu, Yuguang

2017-06-01

Poly(vinyl alcohol) (PVA) was grafted on polybutadiene rubber latex (PBL) particles (PB-g-PVA) by pre-irradiation via emulsion grafting copolymerization. The grafting degree (G%) increased almost linearly with the reaction time and the weight ratio of PVA to the PB latex, while decreased gradually when the irradiation dose is over 30 kGy and the reaction temperature is higher than 60 °C. The grafting efficiency (GE%) has the same trend of the G% but the weight ratio of PVA to PBL, GE% decreased with increasing of PVA adding to PB latex. FTIR spectroscopy indicated that the PVA was grafted onto the PB particles. The dynamic light scattering measurement showed that the particle size of PB-g-PVA particles was larger than that of the pristine PBL particles, and it increased with increment of G%. Transmission electron microscopy images of the PB-g-PVA latex particles demonstrated that the size of PB-g-PVA particle was enlarged by the layer of grafted PVA surrounding the PBL particles. Thermal behavior exhibited the phase separation in the PB-g-PVA films, Tg1 and Tg2 related to the PB and PVA respectively, both of which shifted to a higher temperature with increasing of G%, but the Tg2 was still lower than that of the virgin PVA. The increment of the surface free energy of PB-g-PVA films was attributed to the incorporation of the polar PVA, which also resulted in improvement of the hydrophilic properties.

Latex immunotherapy: evidence of effectiveness

PubMed Central

Nucera, Eleonora; Mezzacappa, Simona; Buonomo, Alessandro; Centrone, Michele; Rizzi, Angela; Manicone, Paolo Francesco; Patriarca, Giampiero; Schiavino, Domenico

2018-01-01

Introduction The only etiological and decisive therapy, able to influence the natural history of latex allergy is the specific desensitization. Aim To verify the clinical efficacy and immunological changes determined by latex sublingual immunotherapy in allergic patients who underwent this treatment for at least 3 years. Material and methods We enrolled 76 patients (16 males and 60 females, mean age 34 years old) with evidence of a natural rubber latex allergy. To assess the effectiveness of the immunotherapy we performed a latex skin prick test, specific IgE and IgG4 and challenge tests before and after at least 3 years of desensitization. Results We observed a reduction in the mean diameter of the wheal area at the skin prick test and a decrease in latex specific IgE while no significant changes of latex IgG4 values were found. Moreover a reduction of symptoms and scores at the provocation tests were remarked. Conclusions Although the primary prevention (which still remains the gold standard treatment for patients suffering from the latex allergy) sublingual immunotherapy can be offered with efficacy in addition to symptomatic treatment to selected patients. PMID:29760613

Finite Element Analysis of Simple Rectangular Microstrip Sensor for Determination Moisture Content of Hevea Rubber Latex

NASA Astrophysics Data System (ADS)

Yahaya, NZ; Ramli, MR; Razak, NNANA; Abbas, Z.

2018-04-01

The Finite Element Method, FEM has been successfully used to model a simple rectangular microstrip sensor to determine the moisture content of Hevea rubber latex. The FEM simulation of sensor and samples was implemented by using COMSOL Multiphysics software. The simulation includes the calculation of magnitude and phase of reflection coefficient and was compared to analytical method. The results show a good agreement in finding the magnitude and phase of reflection coefficient when compared with analytical results. Field distributions of both the unloaded sensor as well as the sensor loaded with different percentages of moisture content were visualized using FEM in conjunction with COMSOL software. The higher the amount of moisture content in the sample the more the electric loops were observed.

Prevalence of and risk factors for latex sensitization in patients with spina bifida.

PubMed

Bernardini, R; Novembre, E; Lombardi, E; Mezzetti, P; Cianferoni, A; Danti, A D; Mercurella, A; Vierucci, A

1998-11-01

We determined the prevalence of and risk factors for latex sensitization in patients with spina bifida. A total of 59 consecutive subjects 2 to 40 years old with spina bifida answered a questionnaire, and underwent a latex skin prick test and determination of serum IgE specific for latex by RAST CAP radioimmunoassay. We also noted the relationships of total serum IgE skin prick tests to common air and food allergens. In addition, skin prick plus prick tests were also done with fresh foods, including kiwi, pear, orange, almond, pineapple, apple, tomato and banana. Latex sensitization was present in 15 patients (25%) according to the presence of IgE specific to latex, as detected by a skin prick test in 9 and/or RAST CAP in 13. Five latex sensitized patients (33.3%) had clinical manifestations, such as urticaria, conjuctivitis, angioedema, rhinitis and bronchial asthma, while using a latex glove and inflating a latex balloon. Atopy was present in 21 patients (35.6%). In 14 patients (23%) 1 or more skin tests were positive for fresh foods using a prick plus prick technique. Tomato, kiwi, and pear were the most common skin test positive foods. Univariate analysis revealed that a history of 5 or more operations, atopy and positive prick plus prick tests results for pear and kiwi were significantly associated with latex sensitization. Multivariate analysis demonstrated that only atopy and a history of 5 or more operations were significantly and independently associated with latex sensitization. A fourth of the patients with spina bifida were sensitized to latex. Atopy and an elevated number of operations were significant and independent predictors of latex sensitization in these cases.

Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups.

PubMed

Mohamed, Azmi; Anas, Argo Khoirul; Bakar, Suriani Abu; Ardyani, Tretya; Zin, Wan Manshol W; Ibrahim, Sofian; Sagisaka, Masanobu; Brown, Paul; Eastoe, Julian

2015-10-01

Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology. Copyright © 2015 Elsevier Inc. All rights reserved.

Permeation of gasoline, diesel, bioethanol (E85), and biodiesel (B20) fuels through six glove materials.

PubMed

Chin, Jo-Yu; Batterman, Stuart A

2010-07-01

Biofuels and conventional fuels differ in terms of their evaporation rates, permeation rates, and exhaust emissions, which can alter exposures of workers, especially those in the fuel refining and distribution industries. This study investigated the permeation of biofuels (bioethanol 85%, biodiesel 20%) and conventional petroleum fuels (gasoline and diesel) through gloves used in occupational settings (neoprene, nitrile, and Viton) and laboratories (latex, nitrile, and vinyl), as well as a standard reference material (neoprene sheet). Permeation rates and breakthrough times were measured using the American Society for Testing and Materials F739-99 protocol, and fuel and permeant compositions were measured by gas chromatography/mass spectrometry. In addition, we estimated exposures for three occupational scenarios and recommend chemical protective clothing suitable for use with motor fuels. Permeation rates and breakthrough times depended on the fuel-glove combination. Gasoline had the highest permeation rate among the four fuels. Bioethanol (85%) had breakthrough times that were two to three times longer than gasoline through neoprene, nitrile Sol-Vex, and the standard reference materials. Breakthrough times for biodiesel (20%) were slightly shorter than for diesel for the latex, vinyl, nitrile examination, and the standard neoprene materials. The composition of permeants differed from neat fuels, e.g., permeants were significantly enriched in the lighter aromatics including benzene. Viton was the best choice among the tested materials for the four fuels tested. Among the scenarios, fuel truck drivers had the highest uptake via inhalation based on the personal measurements available in the literature, and gasoline station attendants had highest uptake via dermal exposure if gloves were not worn. Appropriate selection and use of gloves can protect workers from dermal exposures; however, current recommendations from the National Institute for Occupational Safety and Health should be revised to account for contemporary fuel formulations that routinely contain ethanol.

Current prevalence rate of latex allergy: Why it remains a problem?

PubMed Central

Wu, Miaozong; McIntosh, James; Liu, Jian

2016-01-01

Objectives: This article aims to review the current prevalence rate of latex allergy among healthcare workers, susceptible patients, and the general public, and to investigate why latex is still a ubiquitous occupational health hazard. Methods: Scientific publications on PubMed, particularly those published within the last five years, and current regulations from agencies such as Food and Drug Administration (FDA) were reviewed. Consumer and commercial products that may contain latex were also surveyed. Results: Approximately 12 million tons of natural rubber latex is produced annually and is widely used to manufacture millions of consumer and commercial products. Only limited number of latex-derived products have been approved and regulated by government agencies, such as FDA, whereas the majority of finished products do not label whether they contain latex. Owing to millions of unidentifiable products containing latex and many routes for exposure to latex, preventing contact with latex allergens and reducing the prevalence of latex allergy are more difficult than expected. Reported data suggest that the average prevalence of latex allergy worldwide remains 9.7%, 7.2%, and 4.3% among healthcare workers, susceptible patients, and general population, respectively. Conclusions: Latex-derived products are ubiquitous, and latex allergy remains a highly prevalent health risk in many occupations and to the general population. Developing alternative materials and increasing the ability to identify and label latex-derived products will be practicable approaches to effectively control the health risks associated with latex. PMID:27010091

Allergen concentration in natural rubber latex.

PubMed

Yeang, H-Y; Hamilton, R G; Bernstein, D I; Arif, S A M; Chow, K-S; Loke, Y-H; Raulf-Heimsoth, M; Wagner, S; Breiteneder, H; Biagini, R E

2006-08-01

Hevea brasiliensis latex serum is commonly used as the in vivo and in vitro reference antigen for latex allergy diagnosis as it contains the full complement of latex allergens. This study quantifies the concentrations of the significant allergens in latex serum and examines its suitability as an antigen source in latex allergy diagnosis and immunotherapy. The serum phase was extracted from centrifuged latex that was repeatedly freeze-thawed or glycerinated. Quantitation of latex allergens was performed by two-site immunoenzymetric assays. The abundance of RNA transcripts of the latex allergens was estimated from the number of their clones in an Expressed Sequence Tags library. The latex allergens, Hev b 1, 2, 3, 4, 5, 6, 7 and 13, were detected in freeze-thawed and glycerinated latex serum at levels ranging from 75 (Hev b 6) to 0.06 nmol/mg total proteins (Hev b 4). Hev b 6 content in the latex was up to a thousand times higher than the other seven latex allergens, depending on source and/or preparation procedure. Allergen concentration was reflected in the abundance of mRNA transcripts. When used as the antigen, latex serum may bias the outcome of latex allergy diagnostic tests towards sensitization to Hev b 6. Tests that make use of latex serum may fail to detect latex-specific IgE reactivity in subjects who are sensitized only to allergens that are present at low concentrations. Latex allergy diagnostics and immunotherapy that use whole latex serum as the antigen source may not be optimal because of the marked imbalance of its constituent allergens.

Sensory trick phenomenon improves motor control in pianists with dystonia: prognostic value of glove-effect

PubMed Central

Paulig, Jakobine; Jabusch, Hans-Christian; Großbach, Michael; Boullet, Laurent; Altenmüller, Eckart

2014-01-01

Musician’s dystonia (MD) is a task-specific movement disorder that causes loss of voluntary motor control while playing the instrument. A subgroup of patients displays the so-called sensory trick: alteration of somatosensory input, e.g., by wearing a latex glove, may result in short-term improvement of motor control. In this study, the glove-effect in pianists with MD was quantified and its potential association with MD-severity and outcome after treatment was investigated. Thirty affected pianists were included in the study. Music instrument digital interface-based scale analysis was used for assessment of fine motor control. Therapeutic options included botulinum toxin, pedagogical retraining and anticholinergic medication (trihexyphenidyl). 19% of patients showed significant improvement of fine motor control through wearing a glove. After treatment, outcome was significantly better in patients with a significant pre-treatment sensory trick. We conclude that the sensory trick may have a prognostic value for the outcome after treatment in pianists with MD. PMID:25295014

[Latex gloves dermatitis in health care workers].

PubMed

Mattei, O; Di Martino, T; Ferraro, P

2007-01-01

With regard to health care workers the irritative contact dermatitis represents about the 80% of all the dermopathies in sanitary staff whereas the allergic contact dermatitis covers approximately the 20% of the professional dermatoses. In our study 4 cases of allergy to latex in hospital nurses are presented; the clinical history is described for each of them as well as the resulting judgment of suitability to the specific work. In general population the allergy to latex is estimated to be approximately 1-6%; in sanitary staff it rises to 5-12%. We have to observe that not all the sensitive subjects show symptoms of allergy. Actually the 4 cases described represent less than 1% of the surveyed group. The sensitization is likely to be so reduced also thanks to the application of preventive guide-lines such as the one proposed by NIOSH. In Italy the criteria in preventing allergic reactions to latex are illustrated in a consensus document issued by a study-team from Italian Association of the Health Workers.

Disinfection of gloves: feasible, but pay attention to the disinfectant/glove combination.

PubMed

Scheithauer, S; Häfner, H; Seef, R; Seef, S; Hilgers, R D; Lemmen, S

2016-11-01

Compliance with hand hygiene is complicated by indications for hand disinfection in rapid succession during the care of one patient. In such situations, disinfection of gloves could facilitate better workflow and optimize compliance rates. We analysed the efficacy of disinfecting gloves by comparing an individual effect of five different hand disinfectant solutions in combination with three different glove types. The investigation was performed in accordance with DIN EN 1500:2013. For all combinations, ten analyses were performed, including (1) right/left-hand examination disinfection efficacy after the first and fifth contamination with E. coli K12 NCTC 10538, (2) recovery rates after contamination, (3) reduction efficacy, (4) fingertip immersion culture, and (5) check for tightness. Disinfection of the ungloved hands was taken as an additional benchmark. The disinfection efficacy for all disinfectant/glove combinations was better with rather than without gloves. For eight combinations, the disinfection efficacy was always >5.0 log 10 . There were significant differences within the gloves (P=0.0021) and within the disinfectant product (P=0.0023), respectively. In detail, Nitril Blue Eco-Plus performed significantly better than Vasco Braun (P=0.0017) and Latex Med Comfort (P=0.0493). Descoderm showed a significantly worse performance than Promanum pure (P=0.043). In the check for tightness, only the Vasco Braun gloves showed no leaks in all samples. There were relevant qualitative differences pertaining to the comfort of disinfecting gloves. The disinfection efficacy for the different disinfectant/glove combinations was greater than for the ungloved hands. However, various disinfectant/glove combinations produce relevant differences as regards disinfection efficacy. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Integrity of Disposable Nitrile Exam Gloves Exposed to Simulated Movement

PubMed Central

Phalen, Robert N.; Wong, Weng Kee

2011-01-01

Every year, millions of health care, first responder, and industry workers are exposed to chemical and biological hazards. Disposable nitrile gloves are a common choice as both a chemical and physical barrier to these hazards, especially as an alternative to natural latex gloves. However, glove selection is complicated by the availability of several types or formulations of nitrile gloves, such as low-modulus, medical-grade, low-filler, and cleanroom products. This study evaluated the influence of simulated movement on the physical integrity (i.e., holes) of different nitrile exam glove brands and types. Thirty glove products were evaluated out-of-box and after exposure to simulated whole-glove movement for 2 hr. In lieu of the traditional 1-L water-leak test, a modified water-leak test, standardized to detect a 0.15 ± 0.05 mm hole in different regions of the glove, was developed. A specialized air inflation method simulated bidirectional stretching and whole-glove movement. A worst-case scenario with maximum stretching was evaluated. On average, movement did not have a significant effect on glove integrity (chi-square; p=0.068). The average effect was less than 1% between no movement (1.5%) and movement (2.1%) exposures. However, there was significant variability in glove integrity between different glove types (p ≤ 0.05). Cleanroom gloves, on average, had the highest percentage of leaks, and 50% failed the water-leak test. Low-modulus and medical-grade gloves had the lowest percentages of leaks, and no products failed the water-leak test. Variability in polymer formulation was suspected to account for the observed discrepancies, as well as the inability of the traditional 1-L water-leak test to detect holes in finger/thumb regions. Unexpectedly, greater than 80% of the glove defects were observed in the finger and thumb regions. It is recommended that existing water-leak tests be re-evaluated and standardized to account for product variability. PMID:21476169

Inactivation of Escherichia coli O157:H7 and Salmonella deposited on gloves in a liquid state and subjected to drying conditions.

PubMed

Erickson, Marilyn C; Liao, Jye-Yin; Webb, Cathy C; Habteselassie, Mussie Y; Cannon, Jennifer L

2018-02-02

Gloves are worn by workers harvesting ready-to-eat produce as a deterrent for contaminating the produce with enteric pathogens that may reside on their hands. As fields are not sterile environments, the probability for gloves to become contaminated still exists and therefore it is critical to understand the conditions that affect the survival of pathogens on gloves. Both Escherichia coli O157:H7 and Salmonella deposited on glove surfaces in a liquid state survived longer when the pathogen had been suspended in lettuce sap than when suspended in water. Despite this protection, pathogens deposited on clean single-use gloves were more likely to survive during drying than pathogens deposited on dirty gloves (a film of lettuce sap had been applied to the surface prior to pathogen application and soil had been ground into the gloves). Survival of both E. coli O157:H7 and Salmonella was biphasic with the greatest losses occurring during the first hour of drying followed by much slower losses in the ensuing hours. Pathogens grown in rich media (tryptic soy broth) versus minimal media (M9) as well as those cultured on solid agar versus liquid broth were also more likely to be resistant to desiccation when deposited onto gloves. Although survival of E. coli O157:H7 on nitrile gloves was in general greater than it was on latex gloves, the relative survival of Salmonella on the two glove types was inconsistent. Due to these inconsistencies, no one glove type is considered better than another in reducing the risk for contamination with enteric pathogens. In addition, the extended survival of what are generally referred to as stress-resistant pathogens suggests that gloves either be changed frequently during the day or washed in a disinfectant to reduce the risk of glove contamination that could otherwise contaminate product handled with the contaminated gloves. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR 156.70 - Precautionary statements for human hazards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... mitigate the effect. The precautionary paragraph must be immediately preceded by the appropriate signal... clothing. Wear goggles or face shield and rubber gloves when handling. Harmful or fatal if swallowed...

40 CFR 156.70 - Precautionary statements for human hazards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... mitigate the effect. The precautionary paragraph must be immediately preceded by the appropriate signal... clothing. Wear goggles or face shield and rubber gloves when handling. Harmful or fatal if swallowed...

40 CFR 156.70 - Precautionary statements for human hazards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... mitigate the effect. The precautionary paragraph must be immediately preceded by the appropriate signal... clothing. Wear goggles or face shield and rubber gloves when handling. Harmful or fatal if swallowed...

Permeation of 70% isopropyl alcohol through surgical gloves: comparison of the standard methods ASTM F739 and EN 374.

PubMed

Mäkelä, Erja A; Vainiotalo, Sinikka; Peltonen, Kimmo

2003-06-01

Standard test methods ASTM F739 and EN 374 were compared by assessing the permeation of 70% isopropyl alcohol (2-propanol) through seven brands of surgical gloves. The two standards differ in the flow rates of the collection medium and in the chemical permeation rate at which the breakthrough time (BTT) is detected, the EN detection level being 10 times higher than the permeation rate used by ASTM. In a departure from the EN standard method, a 4 h testing time was used instead of 8 h. All of the tested gloves were from the same manufacturer and were made from either natural rubber (NR) (six brands) or chloroprene rubber (CR) (one brand). Two of the NR glove brands were double layered. For the thin NR gloves (0.22, 0.28 and 0.27 mm) the permeation rates were higher throughout the tests with a flow rate of 474 ml/min (EN) of the collection medium (nitrogen) compared with the permeation rates obtained with a flow rate of 52 ml/min (ASTM). These resulted in BTTs of 4.6, 6.5 and 7.6 min (EN) and 4.8, 6.5 and 9.1 min (ASTM), respectively. No statistical difference could be observed between the BTT values obtained with the two standard methods for any of the thin gloves. Thus, although the ASTM standard has a lower criterion for the detection of permeation, it does not necessarily produce shorter BTTs. For the better barriers the methods yielded more equivalent permeation rate curves and thus the EN BTTs were longer than the ASTM BTTs: the EN results were 21, 80, 122 and >240 min compared with the ASTM results of 12, 32, 38 and 103 min for glove thicknesses of 0.37 (NR), 0.22 + 0.22 (double layered NR), 0.31 + 0.29 (double layered NR) and 0.19 mm (CR), respectively.

On the response of rubbers at high strain rates.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemczura, Johnathan Greenberg

In this report, we examine the propagation of tensile waves of finite deformation in rubbers through experiments and analysis. Attention is focused on the propagation of one-dimensional dispersive and shock waves in strips of latex and nitrile rubber. Tensile wave propagation experiments were conducted at high strain-rates by holding one end fixed and displacing the other end at a constant velocity. A high-speed video camera was used to monitor the motion and to determine the evolution of strain and particle velocity in the rubber strips. Analysis of the response through the theory of finite waves and quantitative matching between themore » experimental observations and analytical predictions was used to determine an appropriate instantaneous elastic response for the rubbers. This analysis also yields the tensile shock adiabat for rubber. Dispersive waves as well as shock waves are also observed in free-retraction experiments; these are used to quantify hysteretic effects in rubber.« less

Study on cord/rubber interface at elevated temperatures by H-pull test method

NASA Astrophysics Data System (ADS)

Jamshidi, M.; Afshar, F.; Mohammadi, N.; Pourmahdian, S.

2005-08-01

Cords are used as reinforcing materials in rubber compounds. To increase cord/rubber interfacial adhesion, they are coated by an adhesive (usually based on resorcinol-formaldehyde-latex). These composites are used in many sectors such as tire and belt industries. Cord/rubber adhesion strength is an important aspect to determine the durability of system. Due to temperature increase during running tires, the adhesion energy becomes different from initial one. To study cord/rubber interface at elevated temperatures, H-adhesion test method was used. H-pull test is a simple method for adhesion evaluation at ambient temperature, so it is usually used for material quality control. In this research, cord/rubber systems were vulcanized at different temperatures and H-adhesion of samples were evaluated at elevated temperatures. Also cord/rubber interface was studied by ATR analyze to determine interfacial interactions kind.

Regulation of MIR Genes in Response to Abiotic Stress in Hevea brasiliensis

PubMed Central

Gébelin, Virginie; Leclercq, Julie; Hu, Songnian; Tang, Chaorong; Montoro, Pascal

2013-01-01

Increasing demand for natural rubber (NR) calls for an increase in latex yield and also an extension of rubber plantations in marginal zones. Both harvesting and abiotic stresses lead to tapping panel dryness through the production of reactive oxygen species. Many microRNAs regulated during abiotic stress modulate growth and development. The objective of this paper was to study the regulation of microRNAs in response to different types of abiotic stress and hormone treatments in Hevea. Regulation of MIR genes differs depending on the tissue and abiotic stress applied. A negative co-regulation between HbMIR398b with its chloroplastic HbCuZnSOD target messenger is observed in response to salinity. The involvement of MIR gene regulation during latex harvesting and tapping panel dryness (TPD) occurrence is further discussed. PMID:24084713

Endocrine disruptive effects of chemicals eluted from nitrile-butadiene rubber gloves using reporter gene assay systems.

PubMed

Satoh, Kanako; Nonaka, Ryouichi; Ohyama, Ken-ichi; Nagai, Fumiko; Ogata, Akio; Iida, Mitsuru

2008-03-01

Disposable gloves made of nitrile-butadiene rubber (NBR) are used for contact with foodstuffs rather than polyvinyl chloride gloves containing di(2-ethylhexyl)phthalate (DEHP), because endocrine-disruptive effects are suspected for phthalate diesters including DEHP. However, 4,4'-butylidenebis(6-t-butyl-m-cresol) (BBBC), 2,4-di-t-butylphenol, and 2,2,4-trimetyl-1,3-pentanediol diisobutyrate can be eluted from NBR gloves, and possibly also detected in food. In this study, we examined the endocrine-disrupting effects of these chemicals via androgen receptor (AR) and estrogen receptor (ER)-mediated pathways using stably transfected reporter gene cell lines expressing AR (AR-EcoScreen system) and ER (MVLN cells), respectively. We also examined the binding activities of these chemicals to AR and ER. The IC50 value of BBBC for antagonistic androgen was in the range of 10(-6)M. The strength of inhibition was about 5 times that of a known androgen antagonist, 1,1'-(2,2-dichloroethylidene)bis[4-chlorobenzene] (p,p'-DDE), and similar to that of bisphenol A. The IC50 value of BBBC for antagonistic estrogen was in the range of 10(-6)M. These results suggest that BBBC and its structural homologue, 4,4'-thiobis(6-t-butyl-m-cresol) are androgen and estrogen antagonists. It is therefore necessary to study these chemicals in vivo, and clarify their effect on the endocrine system.

A Durable Airfield Marking System.

DTIC Science & Technology

1985-06-01

Resin is Mixed with the Black Curing Agent to Form the Epoxy Adhesive ..... ........... 17 14 The Gray Adhesive (White Resin Mixed with Black Curing...rubber 100 0 Polyester (peroxide-catalyzed) 100 0 Urethane 100 0 Epoxy polyamide 100 0 Acrylic latex (TT-P-1952) 100 0 Thermoplastic Tapes Type 1 100 0...suzmarrizes cost data co1parisons for traffic marking tapes, CAS tiles, fluorocarbon composites (Teflon ),and acrylic latex paint TT-P-1952. 8 -p °’. TABLE 2

The Effect of Particles on Electrolytically Polymerized Thin Natural MCF Rubber for Soft Sensors Installed in Artificial Skin.

PubMed

Shimada, Kunio; Mochizuki, Osamu; Kubota, Yoshihiro

2017-04-19

The aim of this study is to investigate the effect of particles as filler in soft rubber sensors installed in artificial skin. We examine sensors made of natural rubber (NR-latex) that include magnetic particles of Ni and Fe₃O₄ using magnetic compound fluid (MCF). The 1-mm thickness of the electrolytically polymerized MCF rubber makes production of comparatively thin rubber sensors feasible. We first investigate the effect of magnetic particles Ni and Fe₃O₄ on the curing of MCF rubber. Next, in order to adjust the electric properties of the MCF rubber, we adopt Al₂O₃ dielectric particles. We investigate the effect of Al₂O₃ particles on changes in electric current, voltage and temperature of electrolytically polymerized MCF rubber liquid, and on the electric properties under the application of normal and shear forces. By adjusting the ratio of Ni, Fe₃O₄, Al₂O₃ and water in MCF rubber with Al₂O₃, it is possible to change the electric properties.

Risk factors for latex allergy in patients with spina bifida and latex sensitization.

PubMed

Bernardini, R; Novembre, E; Lombardi, E; Mezzetti, P; Cianferoni, A; Danti, D A; Mercurella, A; Vierucci, A

1999-05-01

Some subjects with spina bifida (SB) and latex sensitization (cutaneous and/or serum IgE) can have clinical reactions, while others may have no symptoms after the exposure to latex products. This study was carried out to determine the risk factors associated with latex allergy in patients affected with SB and latex sensitization. Fifty-nine consecutive subjects affected with SB, besides answering a questionnaire, underwent a skin-prick test (SPT) to latex and the determination of the specific serum IgE (RAST CAP) to latex. The total serum IgE concentration was determined and SPT to common aero- and food-allergens, skin tests (prick + prick) with fresh foods (kiwi, pear, orange, pineapple, tomato, banana) and RAST CAP to the same foods tested by the prick + prick technique, were also performed. Fifteen out of the 59 subjects (25%) were sensitized to latex according to the presence of IgE to latex detected by SPT (nine patients) and/or RAST CAP (13 patients). Five out of the 15 sensitized patients (33%) suffered from clinical reactions to latex (urticaria, conjunctivitis, angioedema, rhinitis, bronchial asthma) while they were using latex gloves and while inflating latex balloons. In the 15 sensitized patients, the presence of specific latex seric IgE > 3.5 kU/L (>/= class 3), a positive latex SPT, an elevated total serum IgE, and a positive prick + prick and/or a positive RAST CAP to foods, were significant (P < 0.05) risk factors associated with latex symptoms. The other factors tested (age, gender, months of intermittent bladder catheterization, surgical procedures, SPT reactivity and clinical reactions to aero-allergens and food-allergens, skin tests for fresh foods, positive RAST CAP to foods) were not significantly different in symptomatic and asymptomatic patients. Significant risk factors for symptoms to latex in patients with SB and latex sensitization were a presence of specific IgE to latex > 3.5 kU/L, a more frequent positive latex SPT, elevated total IgE, and one or more positive prick + prick and/or RAST CAP to fresh foods.

Moisturizing alcohol hand gels for surgical hand preparation.

PubMed

Jones, R D; Jampani, H; Mulberry, G; Rizer, R L

2000-03-01

With the use of novel formulary technology, unique moisturizing hand gels have been developed that offer significant advantages in perioperative and other health care settings. These advantages include the time-saving capabilities of a waterless formulation, the persistence and effectiveness of a surgical scrub, and the moisturization and protective properties of a lotion. Extensive laboratory and clinical studies, involving in vivo antimicrobial activity against resident and transient flora, skin moisturization on normal and dry skin, and compatibility with latex gloves, have supported these advantages. Nondrying alcohol hand gels can be used for antiseptic hand washing, hand scrubs between procedures (i.e., reentry scrubs), brushless surgical scrubs, moisturizers, and glove-donning aids.

Geospatial application for the identification and monitoring of rubber smallholders in the Malaysian state of Negeri Sembilan

NASA Astrophysics Data System (ADS)

Hafiz Mohd Hazir, Mohd; Muda, Tuan Mohamad Tuan

2016-06-01

The Malaysian rubber industry, especially in the upstream sector, is much dependent on smallholders to produce latex or cup lumps. Identification and monitoring of rubber smallholders are essential tasks when it comes to the Malaysian rubber industry's sustainability. The authorised agencies who support the rubber smallholders can do better planning, arranging, and managing. This paper introduces a method of calculating the total number of smallholders as well as identifying the location of their planted rubber area. The scope of this study only focused on land owners as rubber smallholders in the selected study area of Negeri Sembilan. The land use map provided by the Department of Agriculture Malaysia gave information on distribution of rubber area in Malaysia, while the cadastral map from the Department of Survey and Mapping Malaysia was specifically used for identifying land owners of each rubber parcel or rubber lot. Both data were analyzed and processed with ArcGIS software to extract the information, and the results were then compared to the Malaysian Rubber Board smallholders database.

Installation report : evaluation of asphalt additives.

DOT National Transportation Integrated Search

1987-01-01

Five asphalt additives that are supposed to improve the stability and flexibility characteristics of asphalt concrete were installed in pavement test sections on Route 58 in Halifax County. Polymers, latex rubbers, and a diatomaceous deposit were use...

49 CFR 228.331 - First aid and life safety.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (at least 4 × 4 inches); (2) Two large gauze pads (at least 8 × 10 inches); (3) Two adhesive bandages; (4) Two triangular bandages; (5) One package of gauge roller bandage that is at least 2 inches wide... of tweezers; (9) One roll of adhesive tape; (10) Two pairs of latex gloves; and (11) One...

49 CFR 228.331 - First aid and life safety.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (at least 4 × 4 inches); (2) Two large gauze pads (at least 8 × 10 inches); (3) Two adhesive bandages; (4) Two triangular bandages; (5) One package of gauge roller bandage that is at least 2 inches wide... of tweezers; (9) One roll of adhesive tape; (10) Two pairs of latex gloves; and (11) One...

49 CFR 228.331 - First aid and life safety.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (at least 4 x 4 inches); (2) Two large gauze pads (at least 8 x 10 inches); (3) Two adhesive bandages; (4) Two triangular bandages; (5) One package of gauge roller bandage that is at least 2 inches wide... of tweezers; (9) One roll of adhesive tape; (10) Two pairs of latex gloves; and (11) One...

Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis

PubMed Central

Putranto, Riza-Arief; Herlinawati, Eva; Rio, Maryannick; Leclercq, Julie; Piyatrakul, Piyanuch; Gohet, Eric; Sanier, Christine; Oktavia, Fetrina; Pirrello, Julien; Kuswanhadi; Montoro, Pascal

2015-01-01

Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS). The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD) susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD. PMID:26247941

Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis.

PubMed

Putranto, Riza-Arief; Herlinawati, Eva; Rio, Maryannick; Leclercq, Julie; Piyatrakul, Piyanuch; Gohet, Eric; Sanier, Christine; Oktavia, Fetrina; Pirrello, Julien; Kuswanhadi; Montoro, Pascal

2015-08-04

Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS). The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD) susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD.

The use of gamma irradiation in preparation of polybutadiene rubber nanopowder; Its effect on particle size, morphology and crosslink structure of the powder

NASA Astrophysics Data System (ADS)

Rezaei Abadchi, Majid; Jalali-Arani, Azam

2014-02-01

The aim of this work was the preparation and characterization of polybutadiene rubber (BR) powder by irradiating of rubber lattices using 60Co radiation and spray-drying of them at the appropriate condition. The influences of absorbed dose on the volume swelling ratio, molecular weight between crosslinks, gel fraction, and glass transition temperature of obtained powder were studied. Morphology, size and size distribution of rubber particles were examined by using scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) technique, respectively. Results obtained by LPSA revealed that radiation has no effect on particle size of rubber latex but after drying, adherence properties of rubber particle causes increase in particle size of rubber powder, as shown in SEM photograph. Fourier transform infrared spectroscopy of rubber powders confirmed that with increasing the irradiation dose, characteristic peak corresponds to the >Cdbnd C< double bands decreased. Also Charlesby-Pinner equation was used to evaluate radiation yield.

Pt2L4 protein, a homologue to Hev b 5 from rubber tree, may not be responsible for the cross-reactions to cassava show by people allergic to latex.

PubMed

de Souza, Cláudia Regina Batista; Beezhold, Donald; Carvalho, Luiz Joaquim C Branco

2008-01-01

Pt2L4 is a protein from cassava homologue to Hevb5, a principal allergen from latex. Here we aimed to elucidate immunological relationships between these proteins. Our results revealed that epitopes found in Hev b 5 are not entirely conserved in Pt2L4 which is not recognized by IgE from patients allergic to Hev b 5.

The small RNA profile in latex from Hevea brasiliensis trees is affected by tapping panel dryness.

PubMed

Gébelin, Virginie; Leclercq, Julie; Kuswanhadi; Argout, Xavier; Chaidamsari, Tetty; Hu, Songnian; Tang, Chaorong; Sarah, Gautier; Yang, Meng; Montoro, Pascal

2013-10-01

Natural rubber is harvested by tapping Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg. Harvesting stress can lead to tapping panel dryness (TPD). MicroRNAs (miRNAs) are induced by abiotic stress and regulate gene expression by targeting the cleavage or translational inhibition of target messenger RNAs. This study set out to sequence miRNAs expressed in latex cells and to identify TPD-related putative targets. Deep sequencing of small RNAs was carried out on latex from trees affected by TPD using Solexa technology. The most abundant small RNA class size was 21 nucleotides for TPD trees compared with 24 nucleotides in healthy trees. By combining the LeARN pipeline, data from the Plant MicroRNA database and Hevea EST sequences, we identified 19 additional conserved and four putative species-specific miRNA families not found in previous studies on rubber. The relative transcript abundance of the Hbpre-MIR159b gene increased with TPD. This study revealed a small RNA-specific signature of TPD-affected trees. Both RNA degradation and a shift in miRNA biogenesis are suggested to explain the general decline in small RNAs and, particularly, in miRNAs.

Sensitization to Rubber Accelerators in Northeastern Italy: The Triveneto Patch Test Database.

PubMed

Buttazzo, Silvia; Prodi, Andrea; Fortina, Anna Belloni; Corradin, Maria Teresa; Larese Filon, Francesca

2016-01-01

Natural and synthetic rubbers containing rubber accelerators are well-known causes of occupational skin disease. Allergic contact dermatitis caused by rubber gloves is frequent and has almost exclusively been attributed to contact sensitization to accelerators. This study aimed to evaluate the frequency of rubber accelerators sensitization in the population living in northeastern Italy, to find time trend and a correlation with occupations, and to investigate co-sensitization between rubber accelerators. A population of 23,774 subjects was patch tested in 6 cities in northeastern Italy in the years 1996 to 2012 using carba mix 3%, thiuram mix 1%, benzothiazole (MBT) mix 1%, and isopropyl phenyl paraphenylamine diamine (IPPD) mix 0.6%. The overall frequency of carbamates, MBT, thiurams, and IPPD mix sensitization was 3.4%, 0.65%, 1.75%, and 0.83%, respectively. On a logistic regression analysis (control group: white-collar workers), we found a statistically significant association to carbamates (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.03-1.7) and thiurams (OR, 1.6; 95% CI, 1.1-2.3) for health care workers. Thiuram sensitivity was also significantly associated with dermatitis in maids and restaurant workers (OR, 2.2; 95% CI, 1.4-3.6), hairdressers (OR, 3.6; 95% CI, 1.8-7.1), shop assistants (OR, 2.9; 95% CI, 1.2-6.8), construction workers (OR, 2.7; 95% CI, 1.7-4.1), mechanics (OR, 2.1; 95% CI, 1.3-3.4), and professional drivers (OR, 2.6; 95% CI, 1.2-5.9). In conclusion, our results demonstrated that rubber accelerators have an important role in allergic contact dermatitis in the northeast of Italy and their sensitization is associated significantly with occupations that wear gloves or use chemical substances. Between rubber accelerators tested, carbamates sensitization is prevalent and increasing during considered years.

The design of an irradiator for the continuous processing of liquid latex

NASA Astrophysics Data System (ADS)

Reuter, O.; Langley, R.; Zn, Wan Manshol Bin W.

1998-06-01

This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include ∗ the irradiation vulcanisation of natural latex rubber ∗ disinfection of municipal sewage sludge for agricultural use ∗ sterilisation of liquids in the pharmaceutical and cosmetics industries ∗ industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.

CHARACTERIZATION OF GLOVEBOX GLOVES FOR THE SAVANNAH RIVER SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinko, P.

A task was undertaken to characterize glovebox gloves that are currently used in the facilities at Savannah River Site (SRS) as well as some experimental and advanced compound gloves that have been proposed for use. Gloves from four manufacturers were tested for permeation in hydrogen and air, thermal stability, tensile properties, puncture resistance and dynamic mechanical response. The gloves were compared to each other within the type and also to the butyl rubber glove that is widely used at the SRS. The permeation testing demonstrated that the butyl compounds from three of the vendors behaved similarly and exhibited hydrogen permeabilitiesmore » of .52‐.84 x10{sup ‐7} cc H{sub 2}*cm / (cm{sup 2}*atm). The Viton glove performed at the lower edge of this bound, while the more advanced composite gloves exhibited permeabilities greater than a factor of two compared to butyl. Thermogravimetric analysis was used to determine the amount of material lost under slightly aggressive conditions. Glove losses are important since they can affect the life of glovebox stripper systems. During testing at 90, 120, and 150°C, the samples lost most of the mass in the initial 60 minutes of thermal exposure and as expected increasing the temperature increased the mass loss and shortened the time to achieve a steady state loss. The ranking from worst to best was Jung butyl‐Hypalon with 12.9 %, Piercan Hypalon with 11.4 %, and Jung butyl‐Viton with 5.2% mass loss all at approximately 140°C. The smallest mass losses were experienced by the Jung Viton and the Piercan polyurethane. Tensile properties were measured using a standard dog bone style test. The butyl rubber exhibited tensile strengths of 11‐15 MPa and elongations or 660‐843%. Gloves made from other compounds exhibited lower tensile strengths (5 MPa Viton) to much higher tensile strengths (49 MPa Urethane) with a comparable range of elongation. The puncture resistance of the gloves was measured in agreement with an ASTM standard. The Butyl gloves exhibited puncture resistance from 183 - 296 lbs/in for samples of 0.020 - 0.038 thick. Finally, the glass transition temperature and the elastic and viscoelastic properties as a function of temperature up to maximum use temperature were determined for each glove material using Dynamic Mechanical Analysis. The glass transition temperatures of the gloves were ‐60°C for butyl, ‐30°C for polyurethane, ‐ 16°C Hypalon, ‐16°C for Viton, and ‐24°C for polyurethane‐Hypalon. The glass transition was too complex for the butyl‐Hypalon and butyl‐Viton composite gloves to be characterized by a single glass transition temperature. All of the glass transition temperatures exceed the vendor projected use temperatures.« less

Allergen

MedlinePlus

... animal dander Dust Drugs (such as antibiotics or medicines you put on your skin) Foods (such as egg, peanut, milk, nuts, soy, fish, animal meat, and wheat) Fungal spores Insect and mite feces Insect bites and stings (their venom) Natural rubber latex Pollen

Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muttalib, Siti Nadzirah Abdul, E-mail: sitinadzirah.amn@gmail.com; Othman, Nadras, E-mail: srnadras@usm.my; Ismail, Hanafi, E-mail: ihanafi@usm.my

This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopymore » test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites.« less

Task 3 - Pyrolysis of Plastic Waste. Semiannual report, November 1, 1996--March 31, 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ness, Robert O.; Aulich, Ted R.

1997-12-31

Over the last 50 years, the U.S. Department of Energy (DOE) has produced a wide variety of radioactive wastes from activities associated with nuclear defense and nuclear power generation. These wastes include low-level radioactive solid wastes, mixed wastes, and transuranic (TRU) wastes. A portion of these wastes consists of high- organic-content materials, such as resins, plastics, and other polymers; synthetic and natural rubbers; cellulosic-based materials; and oils, organic solvents, and chlorinated organic solvents. Many of these wastes contain hazardous and/or pyrophoric materials in addition to radioactive species. Physical forms of the waste include ion-exchange resins used to remove radioactive elementsmore » from nuclear reactor cooling water, lab equipment and tools (e.g., measurement and containment vessels, hoses, wrappings, equipment coverings and components, and countertops), oil products (e.g., vacuum pump and lubrication oils), bags and other storage containers (for liquids, solids, and gases), solvents, gloves, lab coats and anti-contamination clothing, and other items. Major polymer and chemical groups found in high-organic-content radioactive wastes include polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), Teflon(TM), polystyrene (PS), nylon, latex, polyethylene terephthalate (PET), vinyl, high-density polyethylene (HDPE), polycarbonate, nitriles, Tygon(R), butyl, and Tyvec(R).« less

Latex Clearing Protein—an Oxygenase Cleaving Poly(cis-1,4-Isoprene) Rubber at the cis Double Bonds

PubMed Central

Hiessl, Sebastian; Böse, Dietrich; Oetermann, Sylvia; Eggers, Jessica; Pietruszka, Jörg

2014-01-01

Gordonia polyisoprenivorans strain VH2, a potent rubber-degrading actinomycete, harbors two latex clearing proteins (Lcps), which are known to be essential for the microbial degradation of rubber. However, biochemical information on the exact role of this protein in the degradation of polyisoprene was lacking. In this study, the gene encoding Lcp1VH2 was heterologously expressed in strains of Escherichia coli, the corresponding protein was purified, and its role in rubber degradation was examined by measurement of oxygen consumption as well as by chromatographic and spectroscopic methods. It turned out that active Lcp1VH2 is a monomer and is responsible for the oxidative cleavage of poly(cis-1,4-isoprene) in synthetic as well as in natural rubber by the addition of oxygen (O2) to the cis double bonds. The resulting oligomers possess repetitive isoprene units with aldehyde (CHO-CH2—) and ketone (—CH2-CO-CH3) functional groups at the termini. Two fractions with average isoprene contents of 18 and 10, respectively, were isolated, thus indicating an endocleavage mechanism. The activity of Lcp1VH2 was determined by applying a polarographic assay. Alkenes, acyclic terpenes, or other rubber-like polymers, such as poly(cis-1,4-butadiene) or poly(trans-1,4-isoprene), are not oxidatively cleaved by Lcp1VH2. The pH and temperature optima of the enzyme are at pH 7 and 30°C, respectively. Furthermore, it was demonstrated that active Lcp1VH2 is a Cu(II)-containing oxygenase that exhibits a conserved domain of unknown function which cannot be detected in any other hitherto-characterized enzyme. The results presented here indicate that this domain might represent a new protein family of oxygenases. PMID:24928880

Analysis of temperature profile and electric field in natural rubber glove due to microwave heating: effects of waveguide position

NASA Astrophysics Data System (ADS)

Keangin, P.; Narumitbowonkul, U.; Rattanadecho, P.

2018-01-01

Natural rubber (NR) is the key raw material used in the manufacture of other products such as rubber band, tire and shoes. Recently, the NR is used in natural rubber glove ( NRG) manufacturing in the industrial and medical fields. This research aims to investigate the electromagnetic wave propagation and heat transfer in NRG due to heating with microwave energy within the microwave oven at a microwave frequency of 2.45 GHz. Three-dimensional model of NRG and microwave oven are considered in this work. The comparative effects of waveguide position on the electric field and temperature profile in NRG when subjected to microwave energy are discussed. The finite element method (FEM) is used to solve the transient Maxwell’s equation coupled with the transient heat transfer equation. The simulation results with computer programs are validated with experimental results. The placement of waveguides in three cases are left hand side of microwave oven, right hand side of microwave oven and left and right hand sides of microwave oven are investigated. The findings revealed that the placing the waveguide on the right side of the microwave oven gives the highest electric field and temperature profile. The values obtained provide an indication toward understanding the study of heat transfer in NRG during microwave heating in the industry.

Design and Building of an Inexpensive and Sturdy Pipet Bulb Filler Port

ERIC Educational Resources Information Center

Danielson, Neil D.; Danielson, Alex P.

2015-01-01

A pipet filler port has been constructed from a 1/4 in. NPT-1/4 in. or -3/8 in. barbed end Kynar plastic male connector fitting and a washer (cut from a latex rubber hose) inserted into the NPT end. The barbed end can secure reliably different sized rubber bulbs such as 1 oz (30 mL pipet capacity) and 2 oz (60 mL pipet capacity) types, and the 1/4…

The welfare significance of the castration of cattle: a review.

PubMed

Stafford, K J; Mellor, D J

2005-10-01

Castration is an ancient husbandry procedure used to produce docile cattle for draught work, to reduce unwanted breeding, and to modify carcass quality. All the physical methods used to castrate cattle have side-effects and cause pain. The plasma cortisol response to castration using Burdizzo clamps and, by inference, the acute pain experienced, is less than that caused by surgical, rubber-ring or latex-band castration. The cortisol response may be influenced by the age of the animal castrated, but this has not been well defined. Local anaesthesia virtually eliminates the cortisol response, and thus the acute pain, caused by rubber-ring or latex-band castration, but needs to be combined with a systemic analgesic such as the non-steroidal anti-inflammatory drug ketoprofen to eliminate the cortisol response to Burdizzo or surgical castration. When used alone, ketoprofen sometimes reduces the cortisol response to Burdizzo or surgical castration but may need to be accompanied by local anaesthesia to eliminate the pain-induced behaviour seen during the castration process itself. Thus, pharmacological methods are available to virtually eliminate the acute pain experienced by calves during the 12 h following castration. The use of these methods is an additional cost for farmers and may be limited by the availability of drugs for farmers to use and the scarcity of veterinarians in farm animal practice.

Quantification of 5'-deoxy-5'-methylthioadenosine in heat-treated natural rubber latex serum.

PubMed

Pitakpornpreecha, Thanawat; Plubrukarn, Anuchit; Wititsuwannakul, Rapepun

2012-01-01

5'-Deoxy-5'-methylthioadenosine (MTA) is one of the biologically active components found in natural rubber latex (NRL) serum, a common waste product from rubber plantations. In this study the contents of MTA in heat-treated NRL serum were measured in order to assess the potential of the serum as an alternative source of MTA. To devise an HPLC/UV-based quantitative analytical protocol for the determination of MTA, and to determine the effect of heat treatment on the content of MTA in NRL serum from various sources. An HPLC/UV-based determination of MTA using an acidic eluant was devised and validated. In the heat treatment, the effect of refluxing times on MTA liberation was evaluated. The quantification protocol was validated with satisfying linearity, limits of detection and quantitation, precisions for peak areas and recovery percentages from intra- and inter-day operations. The amounts of MTA in the NRL sera from various sources increased with heat treatment to yield 5-12 μg MTA/mL of serum. The devised protocol was found to be satisfyingly applicable to the routine determination of MTA in NRL serum. The effect of heat treatment on the content of MTA also indicated another possible use for NRL serum, normally discarded in vast amounts by the rubber industry, as an alternative source of MTA. Copyright © 2011 John Wiley & Sons, Ltd.

Natural rubber latex allergens: new developments.

PubMed

Yeang, Hoong-Yeet

2004-04-01

New allergenic latex proteins have been identified, whereas further information on known latex allergens has emerged in recent years. Although prevalence figures for sensitization to the various latex allergens have been published in several studies in the past, the data have not been collated to facilitate cross-comparison. Salient characteristics of the three most recently identified latex allergens, Hev b 11, 12 and 13 are described, whereas new findings on some of the previously recognized allergens are examined. Hev b 2 is viewed from the standpoint of allergenicity and protein glycosylation, Hev b 4 in relation to its biochemical identity and molecular cloning, Hev b 5 with respect to its recombinant form, and Hev b 6 in connection with conformational IgE epitopes. Reports on sensitization or allergic reaction to purified latex allergens from recent and past work are summarized. The use of latex allergens in latex allergy diagnostics is reviewed and discussed. Thirteen latex allergens have been recognized by the International Union of Immunological Societies. Based on the results of published studies, native Hev b 2, recombinant Hev b 5, native or recombinant Hev b 6, native Hev b 13, and possibly native Hev b 4 are the major allergens relevant to latex-sensitized adults. Although there is an increasing tendency to identify and characterize latex allergens largely on the basis of their recombinant forms, not all such recombinant proteins have been fully validated against their native counterparts with respect to clinical significance.

The Nanny Cam, Latex Gloves, and Two-Finger Touch: New Technologies for Disciplining Bodies

ERIC Educational Resources Information Center

Johnson, Richard T.

2015-01-01

Drawing on a range of personal caregiver experiences and risk analysis frameworks, this paper offers a critical reflection on related policy and practices in the U.S., focusing particularly on risk and it's impact on early childhood education. It develops a critique of the taken for granted imperative to protect children from any and all risks,…

40 CFR 428.114 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false [Reserved] 428.114 Section 428.114 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.114 [Reserved] ...

40 CFR 428.114 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false [Reserved] 428.114 Section 428.114 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.114 [Reserved] ...

The Effect of Particles on Electrolytically Polymerized Thin Natural MCF Rubber for Soft Sensors Installed in Artificial Skin

PubMed Central

Shimada, Kunio; Mochizuki, Osamu; Kubota, Yoshihiro

2017-01-01

The aim of this study is to investigate the effect of particles as filler in soft rubber sensors installed in artificial skin. We examine sensors made of natural rubber (NR-latex) that include magnetic particles of Ni and Fe3O4 using magnetic compound fluid (MCF). The 1-mm thickness of the electrolytically polymerized MCF rubber makes production of comparatively thin rubber sensors feasible. We first investigate the effect of magnetic particles Ni and Fe3O4 on the curing of MCF rubber. Next, in order to adjust the electric properties of the MCF rubber, we adopt Al2O3 dielectric particles. We investigate the effect of Al2O3 particles on changes in electric current, voltage and temperature of electrolytically polymerized MCF rubber liquid, and on the electric properties under the application of normal and shear forces. By adjusting the ratio of Ni, Fe3O4, Al2O3 and water in MCF rubber with Al2O3, it is possible to change the electric properties. PMID:28422061

29 CFR 1910.183 - Helicopters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... mechanically. (e) Personal protective equipment. (1) Personal protective equipment shall be provided and the employer shall ensure its use by employees receiving the load. Personal protective equipment shall consist... device before ground personnel touch the suspended load, unless protective rubber gloves are being worn...

29 CFR 1910.183 - Helicopters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... mechanically. (e) Personal protective equipment. (1) Personal protective equipment shall be provided and the employer shall ensure its use by employees receiving the load. Personal protective equipment shall consist... device before ground personnel touch the suspended load, unless protective rubber gloves are being worn...

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products

Code of Federal Regulations, 2014 CFR

2014-07-01

... products] Organic HAP/Chemical name (CAS No.) Elastomer product/subcategory BR EPI EPR HYP NEO NBL NBR PBR.... NEO = Neoprene. NBL = Nitrile Butadiene Latex. NBR = Nitrile Butadiene Rubber. PBR/SBRS...

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products

Code of Federal Regulations, 2012 CFR

2012-07-01

... products] Organic HAP/Chemical name (CAS No.) Elastomer product/subcategory BR EPI EPR HYP NEO NBL NBR PBR.... NEO = Neoprene. NBL = Nitrile Butadiene Latex. NBR = Nitrile Butadiene Rubber. PBR/SBRS...

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products

Code of Federal Regulations, 2011 CFR

2011-07-01

... products] Organic HAP/Chemical name (CAS No.) Elastomer product/subcategory BR EPI EPR HYP NEO NBL NBR PBR.... NEO = Neoprene. NBL = Nitrile Butadiene Latex. NBR = Nitrile Butadiene Rubber. PBR/SBRS...

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products

Code of Federal Regulations, 2013 CFR

2013-07-01

... products] Organic HAP/Chemical name (CAS No.) Elastomer product/subcategory BR EPI EPR HYP NEO NBL NBR PBR.... NEO = Neoprene. NBL = Nitrile Butadiene Latex. NBR = Nitrile Butadiene Rubber. PBR/SBRS...

The prevalence of latex allergy in children seen in a university hospital allergy clinic.

PubMed

Novembre, E; Bernardini, R; Brizzi, I; Bertini, G; Mugnaini, L; Azzari, C; Vierucci, A

1997-01-01

Natural rubber latex allergy is responsible for a wide spectrum of clinical symptoms, ranging from rhinoconjunctivitis to severe anaphylaxis, in both adults and children. An association between allergy to latex and allergy to various fruits has been reported. This study investigated the prevalence and clinical significance of latex sensitization in children seen in a university hospital allergy clinic. A total of 453 consecutive children were screened in a 7-month period. A detailed clinical history with particular attention to the past surgical history and the eventual presence of latex- or food-induced allergic symptoms was obtained. Skin prick tests (SPT) for the more important inhalant allergens and foods were performed on all children. In patients with positive latex SPT, latex challenge and additional SPT for some fresh foods (avocado, pineapple, apricot, grape, banana, pear, apple, orange, almond, and chestnut) were also performed. RAST for the same food antigens, as well as patch test with latex and a standard battery of contact allergens, was also done. Of 326 atopic children, 10 (3%) presented positive skin test to latex, but only five (1.5%) also had a positive clinical history to latex exposure. Latex challenge was positive in 3/9 positive-latex-SPT children. None of the nonatopic children had positive skin test to latex or symptoms to latex exposure. A history of previous surgery was found in 5/10 positive-latex-SPT children, in 63/316 negative-latex-SPT atopic children (P < 0.05), and in 23/127 nonatopic children. RAST to latex was positive in 5/10 positive-latex-SPT children. Associated fruit-specific IgE (SPT and/or RAST) were found in all latex-symptomatic children and in 2/5 latex-asymptomatic children. Apple, kiwi, and chestnut were the most common SPT-positive foods. Only one patient with clinical allergy to latex and positive skin tests to fruits had a history of clinical symptoms after ingestion of kiwi and orange. The natural history of the positive-latex-SPT children without clinical reactions to latex exposure and the clinical significance of the association of latex and fruit sensitivity require further studies.

Construction and intergeneric conjugative transfer of a pSG5-based cosmid vector from Escherichia coli to the polyisoprene rubber degrading strain Micromonospora aurantiaca W2b.

PubMed

Rose, Karsten; Steinbüchel, Alexander

2002-06-04

A non-rubber degrading mutant of the polyisoprene rubber degrading bacterium Micromonospora aurantiaca W2b lacking the capability to form halos on latex overlay agar plates was isolated after N-methyl-N-nitro-N-nitrosoguanidine mutagenesis. A 10.3-kb shuttle cosmid vector pGM446 was constructed from the Streptomyces cloning vectors pGM160 and pOJ446. This vector was transferred by conjugation from Escherichia coli to M. aurantiaca W2b. The frequency of formation of exconjugants with pGM446 was 3.6 x 10(-3). This vector could be useful for shotgun cloning of genes into the non-rubber degrading mutant L1 from M. aurantiaca W2b.

Characterization of HbWRKY1, a WRKY transcription factor from Hevea brasiliensis that negatively regulates HbSRPP.

PubMed

Wang, Ying; Guo, Dong; Li, Hui-Liang; Peng, Shi-Qing

2013-10-01

Small rubber particle protein (SRPP) is a major component of Hevea brasiliensis (H. brasiliensis) latex, which is involved in natural rubber (NR) biosynthesis. However, little information is available on the regulation of SRPP gene (HbSRPP) expression. To study the transcriptional regulation of HbSRPP, the yeast one-hybrid experiment was performed to screen the latex cDNA library using the HbSRPP promoter as bait. One cDNA that encodes the WRKY transcription factor, designated as HbWRKY1, was isolated from H. brasiliensis. HbWRKY1 contains a 1437 bp open reading frame that encodes 478 amino acids. The deduced HbWRKY1 protein was predicted to possess two conserved WRKY domains and a C2H2 zinc-finger motif. HbWRKY1 was expressed at different levels, with the highest transcription in the flower, followed by the bark, latex, and leaf. Furthermore, the co-expression of pHbSRP::GUS with CaMV35S::HbWRKY1 significantly decreased the GUS activity in transgenic tobacco, indicating that HbWRKY1 significantly suppressed the HbSRPP promoter. These results suggested that HbWRKY1 maybe a negative transcription regulator of HbSRPP involved in NR biosynthesis in H. brasiliensis. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

U.S. Navy Shipboard-Generated Plastic Waste Pilot Recycling Program

DTIC Science & Technology

1991-03-01

2: Recyclable Plastic Items Collected from Lexington Waste at Escambia County MRF Shampoo containers Plastic garbage bags Tyvek suit Shower thongs...bale consisted of polystyrene foam cups, bread bags, bottles, disposable razors, latex gloves, shampoo bottles, and othermiscellaneous items listed in...recent csws telephone survey of recycling firms involved in the separation of mixed 46 plastic bottles, the cost of sorting plastic bottles is

Norovirus Illness: Key Facts

MedlinePlus

... should— • handle soiled items carefully without agitating them, • wear rubber or disposable gloves while handling soiled items and wash your hands after, and wash the items with detergent at the maximum available cycle length then machine dry them. Visit CDC’s Norovirus Web site at ...

Transcriptome analysis in Hevea brasiliensis latex revealed changes in hormone signalling pathways during ethephon stimulation and consequent Tapping Panel Dryness.

PubMed

Montoro, Pascal; Wu, Shuangyang; Favreau, Bénédicte; Herlinawati, Eva; Labrune, Cécile; Martin-Magniette, Marie-Laure; Pointet, Stéphanie; Rio, Maryannick; Leclercq, Julie; Ismawanto, Sigit; Kuswanhadi

2018-05-31

Tapping Panel Dryness (TPD) affects latex production in Hevea brasiliensis. This physiological syndrome involves the agglutination of rubber particles, which leads to partial or complete cessation of latex flow. Latex harvesting consists in tapping soft bark. Ethephon can be applied to stimulate latex flow and its regeneration in laticifers. Several studies have reported transcriptome changes in bark tissues. This study is the first report on deep RNA sequencing of latex to compare the effect of ethephon stimulation and TPD severity. Trees were carefully selected for paired-end sequencing using an Illumina HiSeq 2000. In all, 43 to 60 million reads were sequenced for each treatment in three biological replicates (slight TPD trees without ethephon stimulation, and slight and severe TPD trees with ethephon treatment). Differentially expressed genes were identified and annotated, giving 8,111 and 728 in response to ethephon in slight TPD trees and in ethephon-induced severe TPD trees, respectively. A biological network of responses to ethephon and TPD highlighted the major influence of metabolic processes and the response to stimulus, especially wounding and jasmonate depression in TPD-affected trees induced by ethephon stimulation.

Exposure of natural rubber to personal lubricants--swelling and stress relaxation as potential indicators of reduced seal integrity of non-lubricated male condoms.

PubMed

Sarkar Das, Srilekha; Coburn, James C; Tack, Charles; Schwerin, Matthew R; Richardson, D Coleman

2014-07-01

Male condoms act as mechanical barriers to prevent passage of body fluids. For effective use of condoms the mechanical seal is also expected to remain intact under reasonable use conditions, including with personal lubricants. Absorption of low molecular weight lubricant components into the material of male condoms may initiate material changes leading to swelling and stress relaxation of the polymer network chains that could affect performance of the sealing function of the device. Swelling indicates both a rubber-solvent interaction and stress relaxation, the latter of which may indicate and/or result in a reduced seal pressure in the current context. Swelling and stress relaxation of natural rubber latex condoms were assessed in a laboratory model in the presence of silicone-, glycol-, and water-based lubricants. Within 15 minutes, significant swelling (≥6 %) and stress reduction (≥12 %) of condoms were observed with 2 out of 4 silicone-based lubricants tested, but neither was observed with glycol- or water-based lubricants tested. Under a given strain, reduction in stress was prominent during the swelling processes, but not after the process was complete. Lubricant induced swelling and stress relaxation may loosen the circumferential stress responsible for the mechanical seal. Swelling and stress relaxation behavior of latex condoms in the presence of personal lubricants may be useful tests to identify lubricant-rooted changes in condom-materials. For non-lubricated latex condoms, material characteristics--which are relevant to failure--may change in the presence of a few silicone-based personal lubricants. These changes may in turn induce a loss of condom seal during use, specifically at low strain conditions. Published by Elsevier Inc.

Mechanical & morphological properties of attapulgite/NR composites: Effect of mixing time variation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nor, Nor Aina Mohd, E-mail: ayena90@yahoo.com; Othman, Nadras, E-mail: srnadras@usm.my; Ismail, Hanafi, E-mail: ihanafi@usm.my

2015-07-22

The development of composite material based on attapulgite clay (ATP) as a filler and natural rubber (NR) matrices were prepared by combination of melt mixing and latex compounding methods. Sonication technique was chosen in this work to disperse the attapulgite suspension. 6 phr of attapulgite loading was fabricated using different time of mixing ranging from 30 minutes until 2 hours and sonication time was kept constant at 15 minutes. Then, co-coagulating HA latex with attapulgite clay suspension through latex compounding method produced the masterbatch. The masterbatch was compounded with natural rubber by melt mixing method. The mechanical and morphological characteristicsmore » were investigated in this work. From mechanical testing, M1 showed the highest value of tensile and tear strength. By comparing with M30 and M2, M1 shows high 300% tensile modulus and lower crosslink density. However, when the time of mixing was prolonged to 2 hours, the results for tensile strength, elongation at break and tear strength were decreased. This is due to flocculation of attapulgite particles. Sonication techniques also proved that the tensile strength and elongation at break of these three samples were higher compared to gum NR (NR) and attapulgite compounded with NR using a conventional method (in-situ 6). From field emission scanning electron microscope (FESEM) results, it revealed that M1 had good dispersion in the NR system. It is proved that the higher tensile strength was due to good dispersion of attapulgite clay in the NR matrix. It was also supported from crosslink density, which is lower than NR and in-situ 6 results. It showed that the penetration of toluene solvent into rubber compound was restricted. The optimum time, M1 give the best results, which can be compared to control the sample.« less

Anaesthetic uptake and washout characteristics of patient circuit tubing with special regard to current decontamination techniques.

PubMed

Gilly, H; Weindlmayr-Goettel, M; Köberl, G; Steinbereithner, K

1992-10-01

The amounts of halothane and isoflurane trapped after exposure for up to 3 h at 2 MAC in commonly used anaesthesia circuit tubing were quantitated by gas chromatography. The decontaminating effects of procedures such as flushing with oxygen, thermal disinfection and/or routine storage were assessed in a similar way. After halothane exposure, anaesthetic content was highest in silicone (398 +/- 55 mg 100 g-1). Lower quantities were found in all other tubings investigated (electrically conductive latex: 64 +/- 4, conductive rubber: 62 +/- 4, polyethylene-vinyl-acetate (PEVA): 293 +/- 10 and 149 +/- 17 for non-conductive corrugated and spiral tubes, respectively, polysulfone (Hytrel): 155 +/- 10 mg 100 g-1). The isoflurane contents were substantially lower (silicone: 278 +/- 23; others: 55 +/- 7, 61 +/- 6, 163 +/- 9 and 86 +/- 8, 74 +/- 4 mg 100 g-1). The tubings' content did not correlate with the material's partition coefficient as full saturation was not achieved during exposure. Decontamination procedures reduced the content of volatile anaesthetics to a variable extent. Conductive latex and rubber showed the highest residual content, even after thermal disinfection and subsequent storage. Twenty-minute flushing with oxygen (8 l min-1) decreased effluent gas concentrations below 5 p.p.m. in all tubings. With silicone, after 1 h flushing, halothane concentrations still exceeded 10 p.p.m. (isoflurane: 8 p.p.m.). It is concluded that urgent decontamination by a 20-min flush warrants the safe re-use of previously 'contaminated' conductive rubber and latex as well as polysulfone tubings in critical situations, e.g. in malignant hyperthermia patients if disposable tubing is not immediately available.(ABSTRACT TRUNCATED AT 250 WORDS)

Assembly and analysis of a male sterile rubber tree mitochondrial genome reveals DNA rearrangement events and a novel transcript.

PubMed

Shearman, Jeremy R; Sangsrakru, Duangjai; Ruang-Areerate, Panthita; Sonthirod, Chutima; Uthaipaisanwong, Pichahpuk; Yoocha, Thippawan; Poopear, Supannee; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2014-02-10

The rubber tree, Hevea brasiliensis, is an important plant species that is commercially grown to produce latex rubber in many countries. The rubber tree variety BPM 24 exhibits cytoplasmic male sterility, inherited from the variety GT 1. We constructed the rubber tree mitochondrial genome of a cytoplasmic male sterile variety, BPM 24, using 454 sequencing, including 8 kb paired-end libraries, plus Illumina paired-end sequencing. We annotated this mitochondrial genome with the aid of Illumina RNA-seq data and performed comparative analysis. We then compared the sequence of BPM 24 to the contigs of the published rubber tree, variety RRIM 600, and identified a rearrangement that is unique to BPM 24 resulting in a novel transcript containing a portion of atp9. The novel transcript is consistent with changes that cause cytoplasmic male sterility through a slight reduction to ATP production efficiency. The exhaustive nature of the search rules out alternative causes and supports previous findings of novel transcripts causing cytoplasmic male sterility.

Investigating effects of nano cerium oxide reinforcement on mechanical properties of composite based on natural rubber

NASA Astrophysics Data System (ADS)

Bao, Le Quoc; Phan, Vu Hoang Giang; Khuyen, Nguyen Quang

2018-04-01

Polymer nanocomposites that based on combination of nanomaterials (such as nanoparticles, nanotubes, nanorods, nanofibers, and nanosheets) and polymeric matrices are receiving great attention in research and application. However, separate and homogenous dispersion rather than aggregates of nanoparticles into matrices meet big difficulty due to large interaction between nanoparticles. The poor dispersion leads to low properties of nanocomposites. In this study, we find out the appropriate method to separately disperse cerium oxides (CeO2) nanoparticles into natural rubber, aiming to increase mechanical properties of natural rubber. The SEM images were used to evaluate the dispersion of nano CeO2 in natural rubber matrix. The mechanical properties of nanocomposites were measured after vulcanization to investigate effects of nano CeO2 amount on prepared composite. The findings exhibited that the addition of CeO2 by dispersion of nano CeO2 in water via ultrasonication before mixing with rubber latex, significantly increase modulus, tear and wear resistance of natural rubber.

Structural characterization of alpha-terminal group of natural rubber. 2. Decomposition of branch-points by phospholipase and chemical treatments.

PubMed

Tarachiwin, Lucksanaporn; Sakdapipanich, Jitladda; Ute, Koichi; Kitayama, Tatsuki; Tanaka, Yasuyuki

2005-01-01

The treatment of deproteinized natural rubber (DPNR) latex with phospholipases A(2), B, C, and D decreased significantly the long-chain fatty acid ester contents in DPNR and also the molecular weight and Higgins' k' constant, except for phospholipase D treatment. This indicates the presence of phospholipid molecules in NR, which combine rubber molecules together. Transesterification of DPNR resulted in the decomposition of the functional group at the terminal chain-end (alpha-terminal), including phospholipids and formed linear rubber molecules. The addition of small amounts of ethanol into the DPNR solution reduced the molecular weight and shifted the molecular weight distribution (MWD) comparable to that of transesterified DPNR (TE-DPNR). The addition of diammonium hydrogen phosphate into DPNR-latex in order to remove Mg2+ ions yielded a slight decrease in molecular weight and a slight shift in MWD. The phospholipids are expected to link with mono- and diphosphate groups at the alpha-terminal by hydrogen bonding and/or ionic linkages. The decrease in the molecular weight and Huggins' k' constant of DPNR demonstrates the formation of linear molecules after decomposition of branch-points by this treatment, showing that phospholipids participate in the branching formation of NR. The branch-points formed at the alpha-terminus are postulated to originate predominantly by the association of phospholipids via micelle formation of long-chain fatty acid esters and hydrogen bonding between polar headgroups of phospholipids.

Down-Regulation of Small Rubber Particle Protein Expression Affects Integrity of Rubber Particles and Rubber Content in Taraxacum brevicorniculatum

PubMed Central

Hillebrand, Andrea; Post, Janina J.; Wurbs, David; Wahler, Daniela; Lenders, Malte; Krzyzanek, Vladislav; Prüfer, Dirk; Gronover, Christian Schulze

2012-01-01

The biosynthesis of rubber is thought to take place on the surface of rubber particles in laticifers, highly specialized cells that are present in more than 40 plant families. The small rubber particle protein (SRPP) has been supposed to be involved in rubber biosynthesis, and recently five SRPPs (TbSRPP1–5) were identified in the rubber-producing dandelion species Taraxacum brevicorniculatum. Here, we demonstrate by immunogold labeling that TbSRPPs are localized to rubber particles, and that rubber particles mainly consist of TbSRPP3, 4 and 5 as shown by high-resolution two-dimensional gel electrophoresis and mass spectrometric analysis. We also carried out an RNA-interference approach in transgenic plants to address the function of TbSRPPs in rubber biosynthesis as well as rubber particle morphology and stability. TbSRPP-RNAi transgenic T. brevicorniculatum plants showed a 40–50% reduction in the dry rubber content, but neither the rubber weight average molecular mass nor the polydispersity of the rubber were affected. Although no phenotypical differences to wild-type particles could be observed in vivo, rubber particles from the TbSRPP-RNAi transgenic lines were less stable and tend to rapidly aggregate in expelling latex after wounding of laticifers. Our results prove that TbSRPPs are very crucial for rubber production in T. brevicorniculatum, probably by contributing to a most favourable and stable rubber particle architecture for efficient rubber biosynthesis and eventually storage. PMID:22911861

Trace DNA Sampling Success from Evidence Items Commonly Encountered in Forensic Casework.

PubMed

Dziak, Renata; Peneder, Amy; Buetter, Alicia; Hageman, Cecilia

2018-05-01

Trace DNA analysis is a significant part of a forensic laboratory's workload. Knowing optimal sampling strategies and item success rates for particular item types can assist in evidence selection and examination processes and shorten turnaround times. In this study, forensic short tandem repeat (STR) casework results were reviewed to determine how often STR profiles suitable for comparison were obtained from "handler" and "wearer" areas of 764 items commonly submitted for examination. One hundred and fifty-five (155) items obtained from volunteers were also sampled. Items were analyzed for best sampling location and strategy. For casework items, headwear and gloves provided the highest success rates. Experimentally, eyeglasses and earphones, T-shirts, fabric gloves and watches provided the highest success rates. Eyeglasses and latex gloves provided optimal results if the entire surfaces were swabbed. In general, at least 10%, and up to 88% of all trace DNA analyses resulted in suitable STR profiles for comparison. © 2017 American Academy of Forensic Sciences.

29 CFR 1910.137 - Electrical protective equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... produced by ozone on rubber under mechanical stress into a series of interlacing cracks); (C) An embedded... avoidance of handling sharp objects. (B) Any other class of glove may be used for similar work without...

29 CFR 1910.137 - Electrical protective equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... produced by ozone on rubber under mechanical stress into a series of interlacing cracks); (C) An embedded... avoidance of handling sharp objects. (B) Any other class of glove may be used for similar work without...

29 CFR 1910.137 - Electrical protective equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... produced by ozone on rubber under mechanical stress into a series of interlacing cracks); (C) An embedded... avoidance of handling sharp objects. (B) Any other class of glove may be used for similar work without...

29 CFR 1910.137 - Electrical protective equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... produced by ozone on rubber under mechanical stress into a series of interlacing cracks); (C) An embedded... avoidance of handling sharp objects. (B) Any other class of glove may be used for similar work without...

29 CFR 1910.137 - Electrical protective equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... produced by ozone on rubber under mechanical stress into a series of interlacing cracks); (C) An embedded... avoidance of handling sharp objects. (B) Any other class of glove may be used for similar work without...

Job strain among rubber-glove-factory workers in central Thailand.

PubMed

Sein, Muang Muang; Howteerakul, Nopporn; Suwannapong, Nawarat; Jirachewee, Jirachai

2010-01-01

Job strain has become a major concern because of its potential impacts on worker well-being and performance. This cross-sectional study aimed to assess the prevalence of, and examine factors associated with, job strain among workers in a rubber-glove factory, in a central province of Thailand. A total of 200 workers aged 18-55 yr, who had worked at the factory for at least 6 months, completed the Job Content Questionnaire (JCQ) (Thai Version). Two of 5 scales in the JCQ were used to measure job strain, i.e.; job control and psychological job demand. The prevalence of job strain was 27.5%. Multiple logistic regression analysis indicated two variables significantly associated with job strain: low supervisor social support (adjusted OR=3.08; 95%CI: 1.38-6.91) and high job insecurity (adjusted OR=2.25; 95%CI: 1.04-4.88). Effective training for supervisors, to create good relationships among workers and supervisors, and ensuring steady and secure jobs for good employees, are necessary.

Identification of poly(cis-1,4-Isoprene) degradation intermediates during growth of moderately thermophilic actinomycetes on rubber and cloning of a functional lcp homologue from Nocardia farcinica strain E1.

PubMed

Ibrahim, Ebaid M A; Arenskötter, Matthias; Luftmann, Heinrich; Steinbüchel, Alexander

2006-05-01

The enrichment and isolation of thermophilic bacteria capable of rubber [poly(cis-1,4-isoprene)] degradation revealed eight different strains exhibiting both currently known strategies used by rubber-degrading mesophilic bacteria. Taxonomic characterization of these isolates by 16S rRNA gene sequence analysis demonstrated closest relationships to Actinomadura nitritigenes, Nocardia farcinica, and Thermomonospora curvata. While strains related to N. farcinica exhibited adhesive growth as described for mycolic acid-containing actinomycetes belonging to the genus Gordonia, strains related to A. nitritigenes and T. curvata formed translucent halos on natural rubber latex agar as described for several mycelium-forming actinomycetes. For all strains, optimum growth rates were observed at 50 degrees C. The capability of rubber degradation was confirmed by mineralization experiments and by gel permeation chromatography (GPC). Intermediates resulting from early degradation steps were purified by preparative GPC, and their analysis by infrared spectroscopy revealed the occurrence of carbonyl carbon atoms. Staining with Schiff's reagent also revealed the presence of aldehyde groups in the intermediates. Bifunctional isoprenoid species terminated with a keto and aldehyde function were found by matrix-assisted laser desorption ionization-time-of-flight and electrospray ionization mass spectrometry analyses. Evidence was obtained that biodegradation of poly(cis-1,4-isoprene) is initiated by endocleavage, rather than by exocleavage. A gene (lcp) coding for a protein with high homology to Lcp (latex-clearing protein) from Streptomyces sp. strain K30 was identified in Nocardia farcinica E1. Streptomyces lividans TK23 expressing this Lcp homologue was able to cleave synthetic poly(cis-1,4-isoprene), confirming its involvement in initial polymer cleavage.

Identification of Poly(cis-1,4-Isoprene) Degradation Intermediates during Growth of Moderately Thermophilic Actinomycetes on Rubber and Cloning of a Functional lcp Homologue from Nocardia farcinica Strain E1

PubMed Central

Ibrahim, Ebaid M. A.; Arenskötter, Matthias; Luftmann, Heinrich; Steinbüchel, Alexander

2006-01-01

The enrichment and isolation of thermophilic bacteria capable of rubber [poly(cis-1,4-isoprene)] degradation revealed eight different strains exhibiting both currently known strategies used by rubber-degrading mesophilic bacteria. Taxonomic characterization of these isolates by 16S rRNA gene sequence analysis demonstrated closest relationships to Actinomadura nitritigenes, Nocardia farcinica, and Thermomonospora curvata. While strains related to N. farcinica exhibited adhesive growth as described for mycolic acid-containing actinomycetes belonging to the genus Gordonia, strains related to A. nitritigenes and T. curvata formed translucent halos on natural rubber latex agar as described for several mycelium-forming actinomycetes. For all strains, optimum growth rates were observed at 50°C. The capability of rubber degradation was confirmed by mineralization experiments and by gel permeation chromatography (GPC). Intermediates resulting from early degradation steps were purified by preparative GPC, and their analysis by infrared spectroscopy revealed the occurrence of carbonyl carbon atoms. Staining with Schiff's reagent also revealed the presence of aldehyde groups in the intermediates. Bifunctional isoprenoid species terminated with a keto and aldehyde function were found by matrix-assisted laser desorption ionization-time-of-flight and electrospray ionization mass spectrometry analyses. Evidence was obtained that biodegradation of poly(cis-1,4-isoprene) is initiated by endocleavage, rather than by exocleavage. A gene (lcp) coding for a protein with high homology to Lcp (latex-clearing protein) from Streptomyces sp. strain K30 was identified in Nocardia farcinica E1. Streptomyces lividans TK23 expressing this Lcp homologue was able to cleave synthetic poly(cis-1,4-isoprene), confirming its involvement in initial polymer cleavage. PMID:16672480

40 CFR 428.116 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Pretreatment standards for new sources. 428.116 Section 428.116 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.116...

40 CFR 428.116 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Pretreatment standards for new sources. 428.116 Section 428.116 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428.116...

Genomic diversity and phylogenetic relationships in the genus Parthenium (Asteraceae)

USDA-ARS?s Scientific Manuscript database

Guayule (Parthenium argentatum A. Gray) is a perennial hardwood shrub native to the North American Chihuahuan Desert that holds promise as a sustainable source of natural rubber and hypoallergenic latex. The improvement of guayule for commercial-scale production could be potentially accelerated thro...

Formation of protein complex with the aid of polyethylene glycol for deproteinized natural rubber latex

NASA Astrophysics Data System (ADS)

Wei, Lim Keuw; Ing, Wong Kwee; Badri, Khairiah Haji; Ban, Wong Chong

2013-11-01

The effect of polyethylene glycol (PEG) as a deproteinizing agent in commercial natural rubber latex (NRL) onto the physicochemical properties of the NRL was investigated. Three types of PEG were used namely PEG200, PEG4000 and PEG20000 (molecular weight of 200, 4000 and 20000 g/mol respectively). The optimum amount of PEG in NRL was determined from viscosity changes, protein content and Fourier Transform Infrared spectroscopy. Level of protein reduction was affected by molecular weight of PEG. The addition of PEG in NRL reduced the protein content of NRL (3.30 %) to the lowest (2.01 %) at 0.40 phr of PEG200 due to more attractive hydrophobic interactions between short chains PEG compared to PEG4000 (2.24%) and PEG20000 (2.15%). This was verified through FTIR spectroscopy analysis by observing the primary and secondary amide peak where PEG4000 has lesser absorption at the region compared to with PEG20000.

Ciprofloxacin release using natural rubber latex membranes as carrier.

PubMed

Dias Murbach, Heitor; Jaques Ogawa, Guilherme; Azevedo Borges, Felipe; Romeiro Miranda, Matheus Carlos; Lopes, Rute; Roberto de Barros, Natan; Guedes Mazalli, Alexandre Vinicius; Gonçalves da Silva, Rosângela; Ferreira Cinman, José Luiz; de Camargo Drago, Bruno; Donizetti Herculano, Rondinelli

2014-01-01

Natural rubber latex (NRL) from Hevea brasiliensis is easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior.

Identification and reconstitution of the rubber biosynthetic machinery on rubber particles from Hevea brasiliensis

PubMed Central

Yamashita, Satoshi; Yamaguchi, Haruhiko; Waki, Toshiyuki; Aoki, Yuichi; Mizuno, Makie; Yanbe, Fumihiro; Ishii, Tomoki; Funaki, Ayuta; Tozawa, Yuzuru; Miyagi-Inoue, Yukino; Fushihara, Kazuhisa; Nakayama, Toru; Takahashi, Seiji

2016-01-01

Natural rubber (NR) is stored in latex as rubber particles (RPs), rubber molecules surrounded by a lipid monolayer. Rubber transferase (RTase), the enzyme responsible for NR biosynthesis, is believed to be a member of the cis-prenyltransferase (cPT) family. However, none of the recombinant cPTs have shown RTase activity independently. We show that HRT1, a cPT from Heveabrasiliensis, exhibits distinct RTase activity in vitro only when it is introduced on detergent-washed HeveaRPs (WRPs) by a cell-free translation-coupled system. Using this system, a heterologous cPT from Lactucasativa also exhibited RTase activity, indicating proper introduction of cPT on RP is the key to reconstitute active RTase. RP proteomics and interaction network analyses revealed the formation of the protein complex consisting of HRT1, rubber elongation factor (REF) and HRT1-REF BRIDGING PROTEIN. The RTase activity enhancement observed for the complex assembled on WRPs indicates the HRT1-containing complex functions as the NR biosynthetic machinery. DOI: http://dx.doi.org/10.7554/eLife.19022.001 PMID:27790974

Identification of a Taraxacum brevicorniculatum rubber elongation factor protein that is localized on rubber particles and promotes rubber biosynthesis.

PubMed

Laibach, Natalie; Hillebrand, Andrea; Twyman, Richard M; Prüfer, Dirk; Schulze Gronover, Christian

2015-05-01

Two protein families required for rubber biosynthesis in Taraxacum brevicorniculatum have recently been characterized, namely the cis-prenyltransferases (TbCPTs) and the small rubber particle proteins (TbSRPPs). The latter were shown to be the most abundant proteins on rubber particles, where rubber biosynthesis takes place. Here we identified a protein designated T. brevicorniculatum rubber elongation factor (TbREF) by using mass spectrometry to analyze rubber particle proteins. TbREF is homologous to the TbSRPPs but has a molecular mass that is atypical for the family. The promoter was shown to be active in laticifers, and the protein itself was localized on the rubber particle surface. In TbREF-silenced plants generated by RNA interference, the rubber content was significantly reduced, correlating with lower TbCPT protein levels and less TbCPT activity in the latex. However, the molecular mass of the rubber was not affected by TbREF silencing. The colloidal stability of rubber particles isolated from TbREF-silenced plants was also unchanged. This was not surprising because TbREF depletion did not affect the abundance of TbSRPPs, which are required for rubber particle stability. Our findings suggest that TbREF is an important component of the rubber biosynthesis machinery in T. brevicorniculatum, and may play a role in rubber particle biogenesis and influence rubber production. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Are the surgeons safe during UV-A radiation exposure in collagen cross-linking procedure?

PubMed

Shetty, Rashmi; Shetty, Rohit; Mahendradas, Padmamalini; Shetty, Bhujang K

2012-02-01

To quantify the effect of scattered UV-A radiation used in the collagen cross-linking (CXL) procedure and the amount of radiation reaching the surgeon and the surrounding area and to estimate the dampening effect by various protective devices. In this case series, 3 patients [aged 25-30 (±2.5) years] with keratoconus underwent a CXL procedure with UV-A light and riboflavin. Irradiance was measured using a spectrometer (Model USB2000; Ocean Optics, Inc) for various distances from the source, at various angles, and for different durations of radiation. The spectrometer was also used to measure the dampening effect produced by gown, latex gloves, and UV-protective glasses. Maximum UV-A radiation (1.4 × 10(-9) mW/cm(2)) was measured at 2 cm from the limbus, when the probe was held at a 45-degree angle to the floor. UV-A radiation reaching the surgeon's eye and the abdomen was 3.403 × 10(-11) and 2.36 × 10(-11) mW/cm(2), respectively. Gown, latex gloves, and UV-protective glasses showed dampening effects of 99.58%, 95.01%, and 99.73%, respectively. CXL appears to be a safe procedure with respect to UV-A radiation exposure to the surgeon. Further safety can be ensured by UV-protective devices.

Draft genome sequence of the rubber tree Hevea brasiliensis.

PubMed

Rahman, Ahmad Yamin Abdul; Usharraj, Abhilash O; Misra, Biswapriya B; Thottathil, Gincy P; Jayasekaran, Kandakumar; Feng, Yun; Hou, Shaobin; Ong, Su Yean; Ng, Fui Ling; Lee, Ling Sze; Tan, Hock Siew; Sakaff, Muhd Khairul Luqman Muhd; Teh, Beng Soon; Khoo, Bee Feong; Badai, Siti Suriawati; Aziz, Nurohaida Ab; Yuryev, Anton; Knudsen, Bjarne; Dionne-Laporte, Alexandre; Mchunu, Nokuthula P; Yu, Qingyi; Langston, Brennick J; Freitas, Tracey Allen K; Young, Aaron G; Chen, Rui; Wang, Lei; Najimudin, Nazalan; Saito, Jennifer A; Alam, Maqsudul

2013-02-02

Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified. The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber.

Draft genome sequence of the rubber tree Hevea brasiliensis

PubMed Central

2013-01-01

Background Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Results Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified. Conclusions The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber. PMID:23375136

Mechanical Properties of Graphene-Rubber Nanocomposites

NASA Astrophysics Data System (ADS)

Anhar, N. A. M.; Ramli, M. M.; Hambali, N. A. M. A.; Aziz, A. A.; Mat Isa, S. S.; Danial, N. S.; Abdullah, M. M. A. B.

2017-11-01

This research focused on development of wearable sensor device by using Prevulcanized Natural Rubber (PV) and Epoxidized Natural Rubber (ENR 50) latex incorporated with graphene oxide (GO), graphene paste, graphene powder and reduced graphene oxide (rGO) powder. The compounding formulation and calculation were based on phr (parts per hundred rubber) and all the samples were then tested for mechanical properties using Instron 5565 machine. It was found that the sonication effects on tensile strength may have better quality of tensile strength compared to non-sonicated GO. For PV incorporate GO, the optimum loading was best determined at loading 1.5 phr with or without sonication and similar result was recorded for PV/G. For ENR 50 incorporate graphene paste and rGO powder nanocomposite shows the best optimum was at 3.0 phr with 24 hours’ sonication.

Testing of Disposable Protective Garments Against Isocyanate Permeation From Spray Polyurethane Foam Insulation.

PubMed

Mellette, Michael P; Bello, Dhimiter; Xue, Yalong; Yost, Michael; Bello, Anila; Woskie, Susan

2018-05-12

Diisocyanates (isocyanates), including methylene diphenyl diisocyanate (MDI), are the primary reactive components of spray polyurethane foam (SPF) insulation. They are potent immune sensitizers and a leading cause of occupational asthma. Skin exposure to isocyanates may lead to both irritant and allergic contact dermatitis and possibly contribute to systemic sensitization. More than sufficient evidence exists to justify the use of protective garments to minimize skin contact with aerosolized and raw isocyanate containing materials during SPF applications. Studies evaluating the permeation of protective garments following exposure to SPF insulation do not currently exist. To conduct permeation testing under controlled conditions to assess the effectiveness of common protective gloves and coveralls during SPF applications using realistic SPF product formulations. Five common disposable garment materials [disposable latex gloves (0.07 mm thickness), nitrile gloves (0.07 mm), vinyl gloves (0.07 mm), polypropylene coveralls (0.13 mm) and Tyvek coveralls (0.13 mm)] were selected for testing. These materials were cut into small pieces and assembled into a permeation test cell system and coated with a two-part slow-rise spray polyurethane foam insulation. Glass fiber filters (GFF) pretreated with 1-(9-anthracenylmethyl)piperazine) (MAP) were used underneath the garment to collect permeating isocyanates. GFF filters were collected at predetermined test intervals between 0.75 and 20.00 min and subsequently analyzed using liquid chromatography-tandem mass spectrometry. For each garment material, we assessed (i) the cumulative concentration of total isocyanate, including phenyl isocyanate and three MDI isomers, that effectively permeated the material over the test time; (ii) estimated breakthrough detection time, average permeation rate, and standardized breakthrough time; from which (iii) recommendations were developed for the use of similar protective garments following contamination by two-component spray polyurethane foam systems and the limitations of such protective garments were identified. Each type of protective garment material demonstrated an average permeation rate well below the ASTM method F-739 standardized breakthrough rate threshold of 100.0 ng/cm2 min-1. Disposable latex gloves displayed the greatest total isocyanate permeation rate (4.11 ng/cm2 min-1), followed by the vinyl and nitrile gloves, respectively. The Tyvek coverall demonstrated a greater average rate of isocyanate permeation than the polypropylene coveralls. Typical isocyanate loading was in the range of 900 to 15,000 ng MDI/cm2. Permeation test data collected during this study indicated that each type of protective garment evaluated, provided a considerable level of protection (i.e. 10-110-fold reduction from the level of direct exposure) against the isocyanate component of the SPF insulation mixture. Nitrile gloves and polypropylene coveralls demonstrated the lowest rate of permeation and the lowest cumulative permeation of total isocyanate for each garment type.

Proteins and amino acids as biobased polymer modifiers

USDA-ARS?s Scientific Manuscript database

Natural rubber (NR) is a critical agricultural material vital to industry, medicine, and defense, yet global supply is largely limited to latex from Hevea brasiliensis cultivated in tropical regions. Guayule (Parthenium argentatum), a woody desert shrub indigenous to the U.S. and Mexico, is under de...

40 CFR 428.115 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Standards of performance for new sources. 428.115 Section 428.115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428...

40 CFR 428.115 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Standards of performance for new sources. 428.115 Section 428.115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Foam Subcategory § 428...

Construction, testing and performance report : state study no. 137 : resin modified pavement demonstration project.

DOT National Transportation Integrated Search

2007-09-01

Resin Modified Pavement (RMP) is a composite paving material consisting of a thin layer (2 inches) : of open graded hot mix asphalt (HMA) whose internal air voids (approximately 30% voids) are : filled with a latex rubber-modified portland cement gro...

Rational design of aromatic surfactants for graphene/natural rubber latex nanocomposites with enhanced electrical conductivity.

PubMed

Mohamed, Azmi; Ardyani, Tretya; Abu Bakar, Suriani; Sagisaka, Masanobu; Umetsu, Yasushi; Hamon, J J; Rahim, Bazura Abdul; Esa, Siti Rahmah; Abdul Khalil, H P S; Mamat, Mohamad Hafiz; King, Stephen; Eastoe, Julian

2018-04-15

Graphene nanoplatelets (GNPs) can be dispersed in natural rubber matrices using surfactants. The stability and properties of these composites can be optimized by the choice of surfactants employed as stabilizers. Surfactants can be designed and synthesized to have enhanced compatibility with GNPs as compared to commercially available common surfactants. Including aromatic groups in the hydrophobic chain termini improves graphene compatibility of surfactants, which is expected to increase with the number of aromatic moieties per surfactant molecule. Hence, it is of interest to study the relationship between molecular structure, dispersion stability and electrical conductivity enhancement for single-, double-, and triple-chain anionic graphene-compatible surfactants. Graphene-philic surfactants, bearing two and three chains phenylated at their chain termini, were synthesized and characterized by proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. These were used to formulate and stabilize dispersion of GNPs in natural rubber latex matrices, and the properties of systems comprising the new phenyl-surfactants were compared with commercially available surfactants, sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS). Raman spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM) were used to study structural properties of the materials. Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between surfactant architecture and nanocomposite properties. Small-angle neutron scattering (SANS) was used to study self-assembly structure of surfactants. Of these different surfactants, the tri-chain aromatic surfactant TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate) was shown to be highly graphene-compatible (nanocomposite electrical conductivity = 2.22 × 10 -5  S cm -1 ), demonstrating enhanced electrical conductivity over nine orders of magnitude higher than neat natural rubber-latex matrix (1.51 × 10 -14  S cm -1 ). Varying the number of aromatic moieties in the surfactants appears to cause significant differences to the final properties of the nanocomposites. Copyright © 2018 Elsevier Inc. All rights reserved.

30 CFR 77.606 - Energized trailing cables; handling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Energized trailing cables; handling. 77.606... COAL MINES Trailing Cables § 77.606 Energized trailing cables; handling. Energized medium- and high-voltage trailing cables shall be handled only by persons wearing protective rubber gloves (see § 77.606-1...

46 CFR 96.35-5 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., approved by the Mine Safety and Health Administration (MSHA) and by the National Institute for Occupational Safety and Health (NIOSH), and have at a minimum a 30-minute air supply and full facepiece. (c... the crew are familiar with the operation of the equipment. (f) Boots and gloves shall be of rubber or...

76 FR 40377 - Agency Information Collection Activities; Proposed Collection; Comment Request; Class II Special...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... Guidance Document: Labeling for Natural Rubber Latex Condoms AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA) is announcing an opportunity for public... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2011-N-0492...

Cross-Reactivity between Schistosoma mansoni Antigens and the Latex Allergen Hev b 7: Putative Implication of Cross-Reactive Carbohydrate Determinants (CCDs)

PubMed Central

Doenhoff, Michael J.; El-Faham, Marwa; Liddell, Susan; Fuller, Heidi R.; Stanley, Ronald G.; Schramm, Gabriele; Igetei, Joseph E.

2016-01-01

IgG antibodies produced by rabbits immunized against S. mansoni antigens cross-reacted with aqueous soluble constituents of a variety of allergens. The antibody cross-reactivity was largely sensitive to degradation by treatment of the target antigens with sodium meta-periodate, suggesting the cross-reactivity was due to carbohydrate determinants that were common to both the schistosome and the allergens (CCDs). The reaction between the rabbit antibodies and a 43 kDa molecule in a rubber latex extract was analysed further: tandem mass spectrometry identified the latex molecule as allergen Hev b 7. Rabbit anti-schistosome IgG antibodies purified by acid-elution from solid-phase latex Hev b 7 reacted with the S. mansoni egg antigens IPSE/alpha-1 and kappa-5 and cercarial antigens SPO-1 and a fatty acid-binding protein. Moreover, purified anti-S. mansoni egg, latex cross-reactive antibodies reacted with antigenic constituents of some fruits, a result of potential relevance to the latex-fruit syndrome of allergic reactions. We propose that IgG anti-schistosome antibodies that cross-react with allergens may be able to block IgE-induced allergic reactions and thus provide a possible explanation for the hygiene hypothesis. PMID:27467385

Potential effect of the medicinal plants Calotropis procera, Ficus elastica and Zingiber officinale against Schistosoma mansoni in mice.

PubMed

Seif el-Din, Sayed H; El-Lakkany, Naglaa M; Mohamed, Mona A; Hamed, Manal M; Sterner, Olov; Botros, Sanaa S

2014-02-01

Calotropis procera (Ait.) R. Br. (Asclepiadaceae), Ficus elastica Roxb. (Moraceae) and Zingiber officinale Roscoe (Zingiberaceae) have been traditionally used to treat many diseases. The antischistosomal activity of these plant extracts was evaluated against Schistosoma mansoni. Male mice exposed to 80 ± 10 cercariae per mouse were divided into two batches. The first was divided into five groups: (I) infected untreated, while groups from (II-V) were treated orally (500 mg/kg for three consecutive days) by aqueous stem latex and flowers of C. procera, latex of F. elastica and ether extract of Z. officinale, respectively. The second batch was divided into four comparable groups (except Z. officinale-treated group) similarly treated as the first batch in addition to the antacid ranitidine (30 mg/kg) 1 h before extract administration. Safety, worm recovery, tissues egg load and oogram pattern were assessed. Calotropis procera latex and flower extracts are toxic (50-70% mortality) even in a small dose (250 mg/kg) before washing off their toxic rubber. Zingiber officinale extract insignificantly decrease (7.26%) S. mansoni worms. When toxic rubber was washed off and ranitidine was used, C. procera (stem latex and flowers) and F. elastica extracts revealed significant S. mansoni worm reductions by 45.31, 53.7 and 16.71%, respectively. Moreover, C. procera extracts produced significant reductions in tissue egg load (∼34-38.5%) and positively affected oogram pattern. The present study may be useful to supplement information with regard to C. procera and F. elastica antischistosomal activity and provide a basis for further experimental trials.

Biobased, self-healable, high strength rubber with tunicate cellulose nanocrystals.

PubMed

Cao, Liming; Yuan, Daosheng; Xu, Chuanhui; Chen, Yukun

2017-10-19

Cellulose nanocrystals represent a promising and environmentally friendly reinforcing nanofiller for polymers, especially for rubbers and elastomers. Here, a simple approach via latex mixing is used to fabricate biobased, healable rubber with high strength based on epoxidized natural rubber (ENR). Tunicate cellulose nanocrystals (t-CNs) isolated from marine biomass with a high aspect ratio are used to improve both mechanical properties and self-healing behavior of the material. By introducing dynamic hydrogen bond supramolecular networks between oxygenous groups of ENR and hydroxyl groups on the t-CN surface, together with chain interdiffusion in permanently but slightly cross-linked rubber, self-healing and mechanical properties are facilitated significantly in the resulting materials. Macroscopic tensile healing behavior and microscopic morphology analyses are carried out to evaluate the performance of the materials. Both t-CN content and healing time have significant influence on healing behavior. The results indicate that a synergistic effect between molecular interdiffusion and dynamic hydrogen bond supramolecular networks leads to the improved self-healing behavior.

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azira, A. A., E-mail: azira@lgm.gov.my; Kamal, M. M., E-mail: mazlina@lgm.gov.my; Verasamy, D., E-mail: devaraj@lgm.gov.my

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried outmore » on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.« less

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

NASA Astrophysics Data System (ADS)

Azira, A. A.; Verasamy, D.; Kamal, M. M.

2016-07-01

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

The rubber tree genome reveals new insights into rubber production and species adaptation.

PubMed

Tang, Chaorong; Yang, Meng; Fang, Yongjun; Luo, Yingfeng; Gao, Shenghan; Xiao, Xiaohu; An, Zewei; Zhou, Binhui; Zhang, Bing; Tan, Xinyu; Yeang, Hoong-Yeet; Qin, Yunxia; Yang, Jianghua; Lin, Qiang; Mei, Hailiang; Montoro, Pascal; Long, Xiangyu; Qi, Jiyan; Hua, Yuwei; He, Zilong; Sun, Min; Li, Wenjie; Zeng, Xia; Cheng, Han; Liu, Ying; Yang, Jin; Tian, Weimin; Zhuang, Nansheng; Zeng, Rizhong; Li, Dejun; He, Peng; Li, Zhe; Zou, Zhi; Li, Shuangli; Li, Chenji; Wang, Jixiang; Wei, Dong; Lai, Chao-Qiang; Luo, Wei; Yu, Jun; Hu, Songnian; Huang, Huasun

2016-05-23

The Para rubber tree (Hevea brasiliensis) is an economically important tropical tree species that produces natural rubber, an essential industrial raw material. Here we present a high-quality genome assembly of this species (1.37 Gb, scaffold N50 = 1.28 Mb) that covers 93.8% of the genome (1.47 Gb) and harbours 43,792 predicted protein-coding genes. A striking expansion of the REF/SRPP (rubber elongation factor/small rubber particle protein) gene family and its divergence into several laticifer-specific isoforms seem crucial for rubber biosynthesis. The REF/SRPP family has isoforms with sizes similar to or larger than SRPP1 (204 amino acids) in 17 other plants examined, but no isoforms with similar sizes to REF1 (138 amino acids), the predominant molecular variant. A pivotal point in Hevea evolution was the emergence of REF1, which is located on the surface of large rubber particles that account for 93% of rubber in the latex (despite constituting only 6% of total rubber particles, large and small). The stringent control of ethylene synthesis under active ethylene signalling and response in laticifers resolves a longstanding mystery of ethylene stimulation in rubber production. Our study, which includes the re-sequencing of five other Hevea cultivars and extensive RNA-seq data, provides a valuable resource for functional genomics and tools for breeding elite Hevea cultivars.

Assembly and analysis of a male sterile rubber tree mitochondrial genome reveals DNA rearrangement events and a novel transcript

PubMed Central

2014-01-01

Background The rubber tree, Hevea brasiliensis, is an important plant species that is commercially grown to produce latex rubber in many countries. The rubber tree variety BPM 24 exhibits cytoplasmic male sterility, inherited from the variety GT 1. Results We constructed the rubber tree mitochondrial genome of a cytoplasmic male sterile variety, BPM 24, using 454 sequencing, including 8 kb paired-end libraries, plus Illumina paired-end sequencing. We annotated this mitochondrial genome with the aid of Illumina RNA-seq data and performed comparative analysis. We then compared the sequence of BPM 24 to the contigs of the published rubber tree, variety RRIM 600, and identified a rearrangement that is unique to BPM 24 resulting in a novel transcript containing a portion of atp9. Conclusions The novel transcript is consistent with changes that cause cytoplasmic male sterility through a slight reduction to ATP production efficiency. The exhaustive nature of the search rules out alternative causes and supports previous findings of novel transcripts causing cytoplasmic male sterility. PMID:24512148

Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

PubMed

Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

2015-05-01

Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

The biological safety of condom material can be determined using an in vitro cell culture system.

PubMed

Motsoane, N A; Pretorius, E; Bester, M J; Becker, P J

2001-01-01

Latex products have long been recognized as a cause of latex protein allergy. The increased usage of latex gloves, with the consequent increased occurrence of latex allergies appears to have escalated with increasing awareness of the transmission of HIV-AIDS and other infections. The use of condoms as a means to prevent the transmission of STD's (sexually transmitted diseases) and HIV-AIDS has been widely promoted. Although extensive testing is done to evaluate the physical quality of condoms, no information is available regarding the biological safety of condoms. This study was undertaken to determine the effects of short-term exposure to physiological levels of condom surface material on cell viability (MTT assay) and cell growth (crystal violet assay). A direct contact cell culture testing method (FDA test method F813-83 used to evaluate the cytotoxic potential of medical materials and devices) was used. The modified test method was found to be a sensitive test system for the evaluation of the biological safety of condoms. This study reveals the importance of evaluating the biological safety of all condoms that are commercially available, because of the potential health risk that may be associated with prolonged use of certain types of condoms.

Airfield Damage Recovery Techniques of 18th Engineer Brigade in Europe

DTIC Science & Technology

1980-12-01

have to be observed. Comparable German regulations are published in "Verordnung uber gefAbrliche Arbeitsstoffe", issue May 1, 1976. Ŗ.1. Most important...rules: Rubber boots, acid-prove protective gloves, protective facial masks, water spray bottles for eyes 2.2. No smoking, no eating at jobside 3

76 FR 71575 - Agency Information Collection Activities; Submission for Office of Management and Budget Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-18

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2011-N-0492... Request; Class II Special Controls Guidance Document: Labeling for Natural Rubber Latex Condoms AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA) is...

Effect of strain rate on mechanical properties of melt-processed soy flour composite filler and styrene-butadiene blends

USDA-ARS?s Scientific Manuscript database

Polymer composites were prepared by melt-mixing polymer and soy flour composite fillers in an internal mixer. Soy flour composite fillers were prepared by blending aqueous dispersion of soy flour with styrene-butadiene rubber latex, dried, and cryogenically ground into powders. Upon crosslinking, th...

Interior. Looking from balance room to the front entrance. Chemicals ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Looking from balance room to the front entrance. Chemicals related to Edison's experiments on the extraction of latex for rubber from the goldenrod plant. Room is set up based on reconstruction research done in 1972. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Contact dermatitis in students practicing sports: incidence of rubber sensitisation.

PubMed

Ventura, M T; Dagnello, M; Matino, M G; Di Corato, R; Giuliano, G; Tursi, A

2001-04-01

Over the last few years, changes in cutaneous homoeostasis resulting from sports activities have been reported. In particular, alterations in sweating mechanisms, the hydrolipid barrier, and surface bacterial flora, together with exposure to atmospheric conditions and the need to use medicaments, detergents, and other topical substances, predispose subjects to allergic contact dermatitis. To evaluate the incidence of allergic contact dermatitis in a group of young people practising sports activities. Patch tests were performed to confirm the diagnosis of irritant or allergic dermatitis; in addition, the radioallergoabsorbent test (RAST) to latex was evaluated in the group studied. Allergic contact dermatitis caused by thiourams (23.3%) and mercaptobenzothiazole (20.9%) was prevalent. Other haptens, such as benzocaine and nickel, which are contained in clothing, equipment, topical medicaments, and creams used for massage, were also allergenic. In two cases, RAST positivity to latex was registered. -The results suggest that close contact with sports equipment may increase the incidence of allergic contact dermatitis. Students practising certain sports may have "professional" allergic contact dermatitis to additives used in the production of rubber.

Occupational contact allergic dermatitis in dentistry.

PubMed

Mikov, Ivan; Turkalj, Ivan; Jovanović, Marina

2011-06-01

Dental professionals may be at increased risk of developing occupational allergic diseases specially to methacrylates that can permeate protective disposable gloves. We presented a case of occupational allergic contact dermatitis in a 28-year-old dental technician. The patient had complained of itching and cracking of fingers for 6 months. The dermatitis improved over weekends. Skin erythema and scaling were present with primarily involvement of the fingertips. Patch testing with dental series gave positive vesicular reaction to methyl methacrylate. Follow-up after 6 months of allergen avoidance showed a complete regression of dermatitis. Methacrylates serve as bases for acrylic resins which are used in prosthetics. Methyl methacrylate as a small molecular acrylate can permeate thin protective disposable gloves. Using adequate personal protective equipment, like nitrile rubber gloves, is the most important preventive measure in this occupation. Health practitioners should recognize possible occupational hazards in dentistry and implement appropriate preventive measures to protect health of workers.

Effect of medium modification and selected precursors on sterol production by short-term callus cultures of Euphorbia tirucalli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biesboer, D.D.; Mahlberg, P.G.

1979-01-01

Latex from E. Tirucalli, a potential rubber source, contains steroidal alcohols that are high in energy and thus of value in biomass conversion to fuels. Euphol was present in large amounts in the latex, but tirucallol predominated in greater quantities in explants and callus indicating synthesis and/or accumulation of tirucallol by cells other than the laticifer cell. Sterol production was significantly enhanced by certain nutrient media, as well as indole-3-acetic acid, and depressed by benzyladenine. Precursor stimulation of product synthesis was successful only with squalene, which promoted sterol production at 1.0 mg/liter but inhibited cell growth at higher concentrations. DL-mevalonicmore » acid and lanosterol promoted neither growth nor sterol production. DL-(214C) mevalonate was used to confirm the biosynthesis of sterols in both latex and callus cultures.« less

Rubber Oxygenase and Latex Clearing Protein Cleave Rubber to Different Products and Use Different Cleavage Mechanisms

PubMed Central

Birke, Jakob

2014-01-01

Two types of enzyme for oxidative cleavage of poly(cis-1,4-isoprene) are known. One is rubber oxygenase (RoxA) that is secreted by Xanthomonas sp. strain 35Y and a few other Gram-negative rubber-degrading bacteria during growth on polyisoprene. RoxA was studied in the past, and the recently solved structure showed a structural relationship to bacterial cytochrome c peroxidases (J. Seidel et al., Proc. Natl. Acad. Sci. U. S. A. 110:13833–13838, 2013, http://dx.doi.org/10.1073/pnas.1305560110). The other enzyme is latex-clearing protein (Lcp) that is secreted by rubber-degrading actinomycetes, but Lcp has not yet been purified. Here, we expressed Lcp of Streptomyces sp. strain K30 in a ΔroxA background of Xanthomonas sp. strain 35Y and purified native (untagged) Lcp. The specific activities of Lcp and RoxA were 0.70 and 0.48 U/mg, respectively. Lcp differed from RoxA in the absence of heme groups and other characteristics. Notably, Lcp degraded polyisoprene via endo-type cleavage to tetra-C20 and higher oligo-isoprenoids with aldehyde and keto end groups, whereas RoxA used an exo-type cleavage mechanism to give the main end product 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD). RoxA was able to cleave isolated Lcp-derived oligo-isoprenoid molecules to ODTD. Inhibitor studies, spectroscopic investigations and metal analysis gave no indication for the presence of iron, other metals, or cofactors in Lcp. Our results suggest that Lcp could be a member of the growing group of cofactor-independent oxygenases and differs in the cleavage mechanism from heme-dependent RoxA. In conclusion, RoxA and Lcp represent two different answers to the same biochemical problem, the cleavage of polyisoprene, a polymer that has carbon-carbon double bonds as the only functional groups for enzymatic attack. PMID:24907333

Effect of chitosan content on gel content of epoxized natural rubber grafted with chitosan in latex form.

PubMed

Riyajan, Sa-Ad; Sukhlaaied, Wattana

2013-04-01

The epoxidized natural rubber (ENR) latex-g-chitosan (ENR-g-chitosan) was prepared in latex form using potassium persulphate as an initiator. Firstly, the reduction in molecular weight of chitosan was subjected to the addition of K2S2O8 at 70 °C for 15 min. The structure of the modified chitosan was characterized by ATR-FTIR. Secondarily, the influence of chitosan contents, reaction time, and temperature and K2S2O8 concentrations on the gel content of the modified ENR was investigated. The chemical structure of the ENR-g-chitosan was confirmed by (1)H-NMR and ATR-FTIR. The ether linkage of the ENR-g-chitosan was conformed at 1154 an 1089 cm(-1) by ATR-FTIR and 3.60 ppm by (1)H-NMR. The gel content of ENR-g-chitosan at 5% chitosan showed the highest value compared with other samples. But when chitosan increased from 5% to 10% or 20%, the gel content of ENR-g-chitosan dramatically decreased. The ENR-g-chitosan showed good thermal resistance due to incorporation of chitosan. The morphology of ENR-g-chitosan particle showed the core-shell structure observed by TEM. The optimum condition of grafting ENR with chitosan was found at 65°C for 3h of reaction time, ratio of ENR/chitosan at 9:1. Copyright © 2012 Elsevier B.V. All rights reserved.

Microbial communities in natural rubber coagula during maturation: impacts on technological properties of dry natural rubber.

PubMed

Salomez, M; Subileau, M; Vallaeys, T; Santoni, S; Bonfils, F; Sainte-Beuve, J; Intapun, J; Granet, F; Vaysse, L; Dubreucq, É

2018-02-01

To characterize microbial communities present in natural rubber (NR) coagula from Hevea brasiliensis latex during maturation and identify microbial taxa (bacteria and fungi) having an impact on dry NR properties. Microbial community dynamics in NR coagula maturated under controlled conditions were compared and related with the evolution of dry NR properties. The pyrosequencing of 16S (119 837 effective reads) and 18S (131 879 effective reads) rRNA gene regions was performed on 21 samples covering different maturation times and two aeration conditions. Results showed a relatively high bacterial richness (Chao1 estimates of 200-1000) associated with significant bacterial dynamics. Lactic acid bacteria (LAB) were dominant in the first days of maturation. Then, in aerobic conditions, development of Actinobacteria represented by the family Microbacteriaceae was associated with alkalinization of the samples and a higher sensitivity of NR to thermo-oxidation as evaluated by its plasticity retention index (PRI). In anaerobiosis, the reduced development of bacteria, mostly LAB present, was associated with improved NR properties (higher initial plasticity P 0 and PRI). The involvement of micro-organisms in the evolution of dry NR properties during the maturation of NR coagula was confirmed. The importance of the structure and dynamics of microbial communities is specifically highlighted. Natural rubber is a key elastomer for the tyre industry and for a variety of other applications. The majority of raw NR is obtained by natural coagulation of H. brasiliensis latex under the activity of micro-organisms. An improved understanding of the microbial communities involved in the maturation of NR coagula may lead to an improvement in the production process of raw NR to provide a better consistency in NR quality. © 2017 The Society for Applied Microbiology.

Effectiveness of liquid soap vs. chlorhexidine gluconate for the removal of Clostridium difficile from bare hands and gloved hands.

PubMed

Bettin, K; Clabots, C; Mathie, P; Willard, K; Gerding, D N

1994-11-01

To compare liquid soap versus 4% chlorhexidine gluconate in 4% alcohol for the decontamination of bare or gloved hands inoculated with an epidemic strain of Clostridium difficile. C difficile (6.7 log10 colony-forming units [CFU], 47% spores), was seeded onto bare or latex gloved hands of ten volunteers and allowed to dry. Half the volunteers initially washed with soap and half with chlorhexidine, followed by the other agent 1 week later. Cultures were done with Rodac plates at three sites on the hand: finger/thumbtips, the palmar surfaces of the fingers, and the palm. Statistical comparison was by paired Student's t test. On bare hands, soap and chlorhexidine did not differ in residual bacterial counts on the finger/thumbtips (log10 CFU, 2.0 and 2.1, P = NS) and fingers (log10 CFU, 2.4 and 2.5, P = NS). Counts were too high on bare palms to quantitate. On gloved hands, soap was more effective than chlorhexidine on fingers (log10 CFU 1.3 and 1.7, P < .01) and palms (log10 CFU 1.5 and 2.0, P < .01), but not finger/thumbtips (log10 CFU 1.6 with each, P = NS). Residual C difficile counts were lower on gloved hands than bare hands (P < 0.01 to < 0.0001). The two agents did not differ significantly in residual counts of C difficile on bare hands, but on gloved hands residual counts were lower following soap wash than following chlorhexidine wash. These observations support the use of either soap or chlorhexidine as a handwash for removal of C difficile, but efficacy in the prevention of C difficile transmission must be determined by prospective clinical trials.

Guayule (parthenium argentatum) pyrolysis biorefining: production of hydrocarbon compatible bio-oils from guayule bagasse via tail-gas reactive pyrolysis

USDA-ARS?s Scientific Manuscript database

Guayule (Parthenium argentatum) is a woody desert shrub grown in the southwestern United States as a source of natural rubber, organic resins, and high energy biofuel feedstock from crop residues. We used guayule bagasse, the residual biomass after latex extraction as feedstock in a pyrolysis proces...

The Effects of Inflated Seating Cushions on Engagement in Preschool Circle Time

ERIC Educational Resources Information Center

Seifert, Anna M.; Metz, Alexia E.

2017-01-01

Inflatable balls and cushions made of non-latex rubber can provide alternatives to sitting on the floor/ground or classroom chairs. This study tested the effect of inflatable cushions (wiggle cushions) placed on the floor for seating during circle time in typical preschool classrooms. The effect on attention was tested using alternating periods of…

Glove perforation rate in open lung surgery.

PubMed

Hollaus, P H; Lax, F; Janakiev, D; Wurnig, P N; Pridun, N S

1999-04-01

In open lung surgery the surgical access is encircled by the ribs, which should result in a high glove perforation rate compared with other surgical specialities. Prospectively the surgeon, first and second assistant and the scrub nurse wore double standard latex gloves during 100 thoracotomies. Parameters recorded were: procedure performed, number of perforations, localization of perforation, the seniority of the surgeon, manoeuvre performed at the moment of perforation, immediate cause of perforation, operation time, performance of rib resection during thoracotomy and time of occurrence of the first three perforations. One thousand, six hundred and seventy-three gloves (902 outer, 771 inner) were tested. In 78 operations perforations occurred. There were 150 outer glove perforations (8.9%, 0-8, mean 1.23), 19 inner glove perforations (1.13%, 0-2, mean 0.19). Cutaneous blood exposure was prevented in 78% of all operations and in 87% of all perforations. The perforation rate for the surgeon, the scrub nurse, the first and the second assistant were 61.2, 40.4, 9.7 and 3.1% of all operations, respectively. Rib resection and a duration of more than 2 h resulted in a significant rise of glove perforation rate (P<0.05). The personal experience of the surgeon and the type of operation did not correlate with glove perforation. The immediate cause leading to perforation was named in only 17 cases (13.7%) and comprised contact with bone (seven), a needle stitch (seven) and a production flaw (three). Leaks were localized mostly on the first finger (18%),second finger, (39%) palm and dorsum of the hand (16%). The average occurrence of all first perforations was 38.7 min (range 3-190) after the beginning of surgery, the second after 63.2 min (range 10-195). Fifty-four first perforations (50.5%) were found during the first 30 min of the operation. The reported perforation rate of 78% lies in the highest range of reported perforation rates in different surgical specialities. Double gloving effectively prevented cutaneous blood exposure and thus should become a routine for the thoracic surgeon to prevent transmission of infectious diseases from the patient to the surgeon.

Addition of Rubber to soil damages the functional diversity of soil.

PubMed

Goswami, Madhurankhi; Bhattacharyya, Purnita; Tribedi, Prosun

2017-07-01

Rubber is a polymer of isoprene, consisting mainly of cis-1,4-polyisoprene units. The unmanageable production and its irresponsible disposal pose severe threats to environmental ecology. Therefore, the current study focuses extensively on the ill-effects of Rubber disposal on soil microbial functional diversity as it reflects the health of ecosystem by acting as a key component in ecosystem productivity. To investigate the effect of Rubber on soil microbial functional diversity, soil samples were collected from landfill sites and three different soil microcosms (Rubber treated, untreated, and sterile soil) were prepared. The soil enzymatic activity was determined by fluorescein diacetate hydrolysis followed by the determination of the microbial metabolic potential and functional diversity by average well color development and Shannon-Weaver index (H), respectively. BiOLOG ECO plates were used for determining the microbial functional diversity of the soil microcosms. Higher heterotrophic microbial count as well as higher soil microbial activity was observed in Rubber untreated soil than Rubber treated soil microcosm. The result indicated that the addition of Rubber to soil reduced soil heterotrophic microbial count and soil microbial activity considerably. Similarly, soil microbial metabolic potential as well as microbial functional diversity of soil had been decreased by the addition of Rubber gloves in it. Variation in soil microbial metabolic spectrum between Rubber treated and untreated microcosm was confirmed by multivariate analysis. Collectively, all the results demonstrated that the addition of Rubber to soil reduced the soil microbial functional diversity considerably. Therefore, it is necessary for the commission of serious steps regarding Rubber disposal and protection of the environment from serious environmental issues.

The condom: A turbulent history.

PubMed

Amy, Jean-Jacques; Thiery, Michel

2015-01-01

The literature concerning the history of condoms is replete with errors. The paper Youssef published in 1993 is in our opinion the best. We update and expand the information. To mention only established facts, we accessed primary sources, which are identified in the article. The origin of the term 'condom' remains an enigma. Plausible hypotheses are that it is derived from either (i) the Latin 'condĕre' (to sheathe) or the corresponding noun 'condus' (receptacle); or (ii) the Venetian variant 'gondon' of the Italian word 'guantone' (glove). The earliest identified mention of a similar barrier method is in the legend of Minos and Pasiphae written (in the 2nd century AD) by Antoninus Liberalis. A penile sheath, made from animal gallbladder, was advocated in the 10th century by the Persian physician Al-Akhawayni. The earliest surviving condoms made of animal membranes date back to between 1642 and 1646. Such 'skin' condoms became increasingly popular for prevention of venereal disease, but as early as the 18th century their value as contraceptives was appreciated. Rubber condoms were available from 1855; since 1930, they are made of latex. We mention, in parallel, the most striking changes over time in sexual mores and behaviours, and illustrate these by referring to colourful figures such as, among others, Boswell, Mrs Philips, Casanova, Marguerite Gourdan, and Richard Carlile. Papers related to this topic often contain errors, which we identify. Condoms over time evolved from animal gut receptacles to reliable contraceptives protecting also against certain sexually transmitted infections, including HIV.

Water penetration of grommets: an in vitro study.

PubMed

Ibrahim, Yousef; Fram, Paul; Hughes, Gavin; Phillips, Pete; Owens, David

2017-10-01

The insertion of grommets has been one of the most common procedures carried out by ENT surgeons for patients with persistent middle ear fluid. There has always been apprehension at the use of grommets by patients undertaking swimming or other water sports due to concerns of grommet penetration by water into the middle ear. Despite this, no common consensus exists amongst otolaryngologists regarding post-operative advice following grommet insertion. Most studies focus on surface swimming and do not consider other activities such as diving that patients may undertake. This study aimed to determine the hydrostatic head required for water to pass through a grommet using different water-based solutions. These were selected to simulate conditions such as swimming and showering or bathing. An improved model of a grommeted middle ear (based on previous work by Ricks et al.) was constructed using two 5-ml plastic syringes, latex (from a surgical glove), two rubber neoprene membranes and a Shah Ventilation Tube (1.14 mm). Different water solutions were added to the system and the hydrostatic head measured using digital calipers. The results revealed that the hydrostatic head required to penetrate a grommet is lowest using soapy water and highest with distilled water. The differences between chlorinated water and 3% saline were not significant. We hope that this study can be used in conjunction with previous work to better prepare the ENT surgeon in giving suitable post-operative advice following grommet insertion.

The Genomes of the Non-Clearing-Zone-Forming and Natural-Rubber- Degrading Species Gordonia polyisoprenivorans and Gordonia westfalica Harbor Genes Expressing Lcp Activity in Streptomyces Strains▿ †

PubMed Central

Bröker, Daniel; Dietz, David; Arenskötter, Matthias; Steinbüchel, Alexander

2008-01-01

The latex-clearing protein (LcpK30) from the rubber-degrading bacterium Streptomyces sp. strain K30 is involved in the cleavage of poly(cis-1,4-isoprene), yielding isoprenoid aldehydes and ketones. Lcp homologues have so far been detected in all investigated clearing-zone-forming rubber-degrading bacteria. Internal degenerated oligonucleotides derived from lcp genes of Streptomyces sp. strain K30 (lcpK30), Streptomyces coelicolor strain A3(2), and Nocardia farcinica strains IFM10152 and E1 were applied in PCR to investigate whether lcp homologues occur also in the non-clearing-zone-forming rubber-utilizing bacteria Gordonia polyisoprenivorans strains VH2 and Y2K, Gordonia alkanivorans strain 44187, and Gordonia westfalica strain Kb1, which grow adhesively on rubber. The 1,230- and 1,224-bp lcp-homologous genes from G. polyisoprenivorans strain VH2 (lcpVH2) and G. westfalica strain Kb1 (lcpKb1) were obtained after screening genomic libraries by degenerated PCR amplification, and their translational products exhibited 50 and 52% amino acid identity, respectively, to LcpK30. Recombinant lcpVH2 and lcpKb1 harboring cells of the non-rubber-degrading Streptomyces lividans strain TK23 were able to form clearing zones and aldehydes on latex overlay-agar plates, thus indicating that lcpVH2 and lcpKb1 encode functionally active proteins. Analysis by gel permeation chromatography demonstrated lower polymer concentrations and molecular weights of the remaining polyisoprenoid molecules after incubation with these recombinant S. lividans strains. Reverse transcription-PCR analysis demonstrated that lcpVH2 was transcribed in cells of G. polyisoprenivorans strain VH2 cultivated in the presence of poly(cis-1,4-isoprene) but not in the presence of sodium acetate. Anti-LcpK30 immunoglobulin Gs, which were raised in this study, were rather specific for LcpK30 and did not cross-react with LcpVH2 and LcpKb1. A lcpVH2 disruption mutant was still able to grow with poly(cis-1,4-isoprene) as sole carbon source; therefore, lcpVH2 seems not to be essential for rubber degradation in G. polyisoprenivorans. PMID:18296529

SNP Identification from RNA Sequencing and Linkage Map Construction of Rubber Tree for Anchoring the Draft Genome

PubMed Central

Shearman, Jeremy R.; Sangsrakru, Duangjai; Jomchai, Nukoon; Ruang-areerate, Panthita; Sonthirod, Chutima; Naktang, Chaiwat; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2015-01-01

Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly. PMID:25831195

SNP identification from RNA sequencing and linkage map construction of rubber tree for anchoring the draft genome.

PubMed

Shearman, Jeremy R; Sangsrakru, Duangjai; Jomchai, Nukoon; Ruang-Areerate, Panthita; Sonthirod, Chutima; Naktang, Chaiwat; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2015-01-01

Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly.

Responses of rubber leaf phenology to climatic variations in Southwest China

NASA Astrophysics Data System (ADS)

Zhai, De-Li; Yu, Haiying; Chen, Si-Chong; Ranjitkar, Sailesh; Xu, Jianchu

2017-11-01

The phenology of rubber trees (Hevea brasiliensis) could be influenced by meteorological factors and exhibits significant changes under different geoclimates. In the sub-optimal environment in Xishuangbanna, rubber trees undergo lengthy periods of defoliation and refoliation. The timing of refoliation from budburst to leaf aging could be affected by powdery mildew disease (Oidium heveae), which negatively impacts seed and latex production. Rubber trees are most susceptible to powdery mildew disease at the copper and leaf changing stages. Understanding and predicting leaf phenology of rubber trees are helpful to develop effective means of controlling the disease. This research investigated the effect of several meteorological factors on different leaf phenological stages in a sub-optimal environment for rubber cultivation in Jinghong, Yunnan in Southwest China. Partial least square regression was used to quantify the relationship between meteorological factors and recorded rubber phenologies from 2003 to 2011. Minimum temperature in December was found to be the critical factor for the leaf phenology development of rubber trees. Comparing the delayed effects of minimum temperature, the maximum temperature, diurnal temperature range, and sunshine hours were found to advancing leaf phenologies. A comparatively lower minimum temperature in December would facilitate the advancing of leaf phenologies of rubber trees. Higher levels of precipitation in February delayed the light green and the entire process of leaf aging. Delayed leaf phenology was found to be related to severe rubber powdery mildew disease. These results were used to build predictive models that could be applied to early warning systems of rubber powdery mildew disease.

Partitioning an Artificial Anterior Chamber With a Latex Diaphragm to Simulate Anterior and Posterior Segment Pressure Dynamics: The "DMEK Practice Stage," Where Surgeons Can Rehearse the "DMEK Dance".

PubMed

Sáles, Christopher S; Straiko, Michael D; Fernandez, Ana Alzaga; Odell, Kelly; Dye, Philip K; Tran, Khoa D

2018-02-01

To present a novel apparatus for simulating the anterior and posterior segment pressure dynamics involved in executing Descemet membrane endothelial keratoplasty (DMEK) surgery when using a chamber-shallowing technique. An artificial anterior chamber (AAC), 18-mm trephine, latex glove, two 3-mL syringes, and one donor cornea comprising an intact corneoscleral cap from which a DMEK tissue was peeled and punched are required for the model. After making the corneal incisions with the corneoscleral cap mounted on the AAC in the usual fashion, the corneoscleral cap is remounted onto the dried AAC over an 18-mm latex diaphragm. The space between the latex diaphragm and the cornea is filled with saline to pressurize the anterior chamber, and the posterior segment is pressurized with air from a syringe. The resulting apparatus comprises a posterior segment and anterior chamber that exert pressure on each other by way of a distensible latex diaphragm. A novice and experienced DMEK surgeon and 2 eye bank technicians were able to assemble the apparatus and perform the routine steps of a DMEK procedure, including maneuvers that require shallowing the anterior chamber and lowering its pressure. Only one cornea was required per apparatus. We present a novel in vitro model of the human eye that more closely mimics the anterior and posterior segment pressure dynamics of in vivo DMEK surgery than average human and animal cadaveric globes. The model is easy to assemble, inexpensive, and applicable to a range of teaching environments.

Ethylene Response Factors Are Controlled by Multiple Harvesting Stresses in Hevea brasiliensis

PubMed Central

Putranto, Riza-Arief; Duan, Cuifang; Kuswanhadi; Chaidamsari, Tetty; Rio, Maryannick; Piyatrakul, Piyanuch; Herlinawati, Eva; Pirrello, Julien; Dessailly, Florence; Leclercq, Julie; Bonnot, François; Tang, Chaorong; Hu, Songnian; Montoro, Pascal

2015-01-01

Tolerance of recurrent mechanical wounding and exogenous ethylene is a feature of the rubber tree. Latex harvesting involves tapping of the tree bark and ethephon is applied to increase latex flow. Ethylene is an essential element in controlling latex production. The ethylene signalling pathway leads to the activation of Ethylene Response Factor (ERF) transcription factors. This family has been identified in Hevea brasiliensis. This study set out to understand the regulation of ERF genes during latex harvesting in relation to abiotic stress and hormonal treatments. Analyses of the relative transcript abundance were carried out for 35 HbERF genes in latex, in bark from mature trees and in leaves from juvenile plants under multiple abiotic stresses. Twenty-one HbERF genes were regulated by harvesting stress in laticifers, revealing an overrepresentation of genes in group IX. Transcripts of three HbERF-IX genes from HbERF-IXc4, HbERF-IXc5 and HbERF-IXc6 were dramatically accumulated by combining wounding, methyl jasmonate and ethylene treatments. When an ethylene inhibitor was used, the transcript accumulation for these three genes was halted, showing ethylene-dependent induction. Subcellular localization and transactivation experiments confirmed that several members of HbERF-IX are activator-type transcription factors. This study suggested that latex harvesting induces mechanisms developed for the response to abiotic stress. These mechanisms probably depend on various hormonal signalling pathways. Several members of HbERF-IX could be essential integrators of complex hormonal signalling pathways in Hevea. PMID:25906196

Microgravity

NASA Image and Video Library

1997-03-11

This photo shows a rubber glove and its attachment ring for the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

Opportunities and obstacles in translating evidence to policy in occupational asthma.

PubMed

Tarlo, Susan M; Arif, Ahmed A; Delclos, George L; Henneberger, Paul; Patel, Jenil

2018-06-01

Occupational asthma (OA), a common respiratory disorder in Western countries, is caused by exposures at the workplace. It is part of a broader definition of work-related asthma (WRA) that also includes pre-existing asthma aggravated by substances present in the workplace environment, and it is potentially preventable. The purpose of this paper is to illustrate preventive measures for occupational asthma by case studies. In three case studies we discuss preventive measures that have been associated with reductions in incidence of occupational asthma from natural rubber latex and from diisocyanates as supported by published literature. We also discuss challenges in relation to asthma from cleaning products in healthcare work. Several preventive measures have been associated with reduction in incidence of occupational asthma from natural rubber latex and from diisocyanates, and may provide lessons for prevention of other causes of occupational asthma. Cleaning products remain an unresolved problem at present with respect to asthma risks but potential measures include the use of safer products and safer applications such as avoidance of spray products, use of occupational hygiene methods such as improving local ventilation, and when appropriate, the use of personal protective devices. Copyright © 2017 Elsevier Inc. All rights reserved.

Opportunities and obstacles in translating evidence to policy in occupational asthma

PubMed Central

Tarlo, Susan M.; Arif, Ahmed A.; Delclos, George L.; Henneberger, Paul; Patel, Jenil

2018-01-01

Purpose Occupational asthma (OA), a common respiratory disorder in Western countries, is caused by exposures at the workplace. It is part of a broader definition of work-related asthma (WRA) that also includes pre-existing asthma aggravated by substances present in the workplace environment, and it is potentially preventable. The purpose of this paper is to illustrate preventive measures for occupational asthma by case studies. Methods In three case studies we discuss preventive measures that have been associated with reductions in incidence of occupational asthma from natural rubber latex and from diisocyanates as supported by published literature. We also discuss challenges in relation to asthma from cleaning products in healthcare work. Results and conclusions Several preventive measures have been associated with reduction in incidence of occupational asthma from natural rubber latex and from diisocyanates, and may provide lessons for prevention of other causes of occupational asthma. Cleaning products remain an unresolved problem at present with respect to asthma risks but potential measures include the use of safer products and safer applications such as avoidance of spray products, use of occupational hygiene methods such as improving local ventilation, and when appropriate, the use of personal protective devices. PMID:28434545

HbMADS4, a MADS-box Transcription Factor from Hevea brasiliensis, Negatively Regulates HbSRPP.

PubMed

Li, Hui-Liang; Wei, Li-Ran; Guo, Dong; Wang, Ying; Zhu, Jia-Hong; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

In plants MADS-box transcription factors (TFs) play important roles in growth and development. However, no plant MADS-box gene has been identified to have a function related to secondary metabolites regulation. Here, a MADS-box TF gene, designated as HbMADS4 , was isolated from Hevea brasiliensis by the yeast one-hybrid experiment to screen the latex cDNA library using the promoter of the gene encoding H. brasiliensis small rubber particle protein (HbSRPP) as bait. HbMADS4 was 984-bp containing 633-bp open reading frame encoding a deduced protein of 230 amino acid residues with a typical conserved MADS-box motif at the N terminus. HbMADS4 was preferentially expressed in the latex, but little expression was detected in the leaves, flowers, and roots. Its expression was inducible by methyl jasmonate and ethylene. Furthermore, transient over-expression and over-expression of HbMADS4 in transgenic tobacco plants significantly suppressed the activity of the HbSRP promoter. Altogether, it is proposed that HbMADS4 is a negative regulator of HbSRPP which participates in the biosynthesis of natural rubber.

Occurrence of coring in insulin vials and possibility of rubber piece contamination by self-injection.

PubMed

Asakura, T; Seino, H; Nozaki, S; Abe, R

2001-06-01

Coring is reported to occur because rubber pieces are shaved off from a rubber stopper when a needle is inserted into the rubber stopper of transfusion liquid formulation. We verified whether coring really occurs in insulin vials of self-injecting patients. We collected insulin cartridges from 30 hospitalized patients and used the primary injection (trial injection), the secondary injection and the cartridge remaining preparation as samples. We observed the rubber pieces using a microscope and measured the shape, number of pieces. The occurrence rate of coring was 73% for the primary injection, 47% for the secondary injection and 97% for the cartridge remaining preparation. The rubber pieces in the primary injection and the secondary injection which went through the needle are mostly in aggregate shape and the rubber pieces in the cartridge remaining preparation which did not go through the needle are mostly in needle-like shape. A number of small rubber pieces are found in both the primary injection and the secondary injection, indicating a high possibility that rubber pieces may be injected under subcutaneous tissue. The coring is considered to occur because needles are repeatedly inserted and rotated at the same spot. It is required to improve the structure to mount a needle to the pen-type injector in future. Coring is a very serious problem from the medical and pharmaceutical points of view. Further study should be made on the implication to latex allergy and lipodystrophy.

Transducer hygiene: comparison of procedures for decontamination of ultrasound transducers and their use in clinical practice.

PubMed

Häggström, Mikael; Spira, Jack; Edelstam, Greta

2015-02-01

To determine whether current hygiene practices are appropriate during sonographic examinations. Five major hospitals in Sweden were investigated with a survey. At each hospital, the departments corresponding to the main types of sonographic examination were chosen. Personnel who were responsible for or acquainted with the local hygiene procedures completed a standardardized questionnaire. The surveys were completed by 25 departments, where the total number of sonographic examinations was approximately 20,000 per month. For transvaginal and transrectal sonographic examinations, the most common method for decontamination of the transducer was barrier protection during the procedure followed by cleansing with alcohol. Latex was the predominant cover material, but one department used polyethylene gloves, and another department used nitrile gloves. Both of these involved transvaginal ultrasonography. In transcutaneous examinations, all hospitals were using alcohol and paper or cloth for decontamination at a minimum. Transesophageal examinations were carried out without barrier protection, and decontamination was performed with an alkylating substance. The hygiene practices appear to be appropriate at most hospitals, but there is a prevalence of transducer cover materials of unacceptable permeability, as well as use of gloves on transducers despite insufficient evidence of safety. © 2015 Wiley Periodicals, Inc.

Fungicide application practices and personal protective equipment use among orchard farmers in the agricultural health study.

PubMed

Hines, C J; Deddens, J A; Coble, J; Alavanja, M C R

2007-04-01

Fungicides are routinely applied to deciduous tree fruits for disease management. Seventy-four private orchard applicators enrolled in the Agricultural Health Study participated in the Orchard Fungicide Exposure Study in 2002-2003. During 144 days of observation, information was obtained on chemicals applied and applicator mixing, application, personal protective, and hygiene practices. At least half of the applicators had orchards with <100 trees. Air blast was the most frequent application method used (55%), followed by hand spray (44%). Rubber gloves were the most frequently worn protective equipment (68% mix; 59% apply), followed by respirators (45% mix; 49% apply), protective outerwear (36% mix; 37% apply), and rubber boots (35% mix; 36% apply). Eye protection was worn while mixing and applying on only 35% and 41% of the days, respectively. Bivariate analyses were performed using repeated logistic or repeated linear regression. Mean duration of mixing, pounds of captan applied, total acres sprayed, and number of tank mixes sprayed were greater for air blast than for hand spray (p < 0.05). Spraying from a tractor/vehicle without an enclosed cab was associated with wearing some type of coverall (p < 0.05). Applicators often did not wash their hands after mixing (77%), a finding not explained by glove use. Glove use during mixing was associated with younger age, while wearing long-sleeve shirts was associated with older age (p < 0.05 each). Self-reported unusually high fungicide exposures were more likely on days applicators performed repairs (p < 0.05). These data will be useful for evaluating fungicide exposure determinants among orchard applicators.

The Short-term Protective Effects of ‘Non-PPE’ Gloves Used by Greenhouse Workers

PubMed Central

Roff, Martin

2015-01-01

Task-based worker exposure assessments are used in regulatory product approval for pesticides. Some agricultural workers may be exposed to pesticide residues predominantly via transfer to the hands during plant tending or crop harvesting. They may use thin ‘splash-resistant single-use’ (SRSU) gloves or cotton gloves as good industry practice, for example, to protect a delicate crop from bruising, rather than specifically for chemical protection. These ‘non-personal protective equipment (PPE)’ gloves may or may not have been tested for chemical resistance, but can nevertheless give limited protection from chemicals. This paper reports experiments to assess the protection factors (PFs) of ‘non-PPE’ gloves against chemicals, to better inform the regulatory exposure assessments. One type of lightweight cotton and three types of 0.1 mm SRSU gloves 25cm long (latex, nitrile, and vinyl) that might be used as ‘non-PPE’ gloves and one type of 0.4 mm PPE nitrile gauntlet 33cm long were worn by 36 volunteers in greenhouses at four nurseries, handling plants sprayed with transferable but non-permeating strontium acetate in four consecutive 1-h sessions, including one session in which no gloves were worn. Dislodgeable foliar residues were measured by rinsing leaves in bags. Each subject carried out their task such as weeding or trimming, for their four sessions on their set of plants. Handwashes followed each session, and the washings were sampled and analysed for strontium. Unprotected hand contamination was taken to be the within-subject ‘challenge’ in the absence of gloves. It ranged from 166 to 4091 µg equivalent of strontium acetate on the hands and increased with increasing foliar residues. Geometric mean PFs were 60 (95% CI 38–87, n = 22) for PPE gauntlets, 32 (25–41, n = 65) for SRSU gloves and 5.3 (3.5–8, n = 21) for lightweight cotton. The PFs offered by the waterproof gloves (gauntlets and SRSU) increased with challenge, but for the absorbent cotton gloves it decreased. The measurement of protection is restricted by the limit of quantification (LOQ) such that protection must apparently increase with challenge, nevertheless the above trends remained even after removal of data

Natural Rubber Nanocomposite with Human-Tissue-Like Mechanical Characteristic

NASA Astrophysics Data System (ADS)

Murniati, Riri; Novita, Nanda; Sutisna; Wibowo, Edy; Iskandar, Ferry; Abdullah, Mikrajuddin

2017-07-01

The blends of synthetic rubber and natural rubber with nanosilica were prepared using a blending technique in presence of different filler volume fraction. The effect of filler on morphological and mechanical characteristics was studied. Utilization of human cadaver in means of medical study has been commonly used primarily as tools of medical teaching and training such as surgery. Nonetheless, human cadaver brought inevitable problems. So it is necessary to find a substitute material that can be used to replace cadavers. In orthopaedics, the materials that resemble in mechanical properties to biological tissues are elastomers such as natural rubber (latex) and synthetic rubber (polyurethanes, silicones). This substitution material needs to consider the potential of Indonesia to help the development of the nation. Indonesia is the second largest country producer of natural rubber in the world. This paper aims to contribute to adjusting the mechanical properties of tissue-mimicking materials (TMMs) to the recommended range of biological tissue value and thus allow the development of phantoms with greater stability and similarity to human tissues. Repeatability for the phantom fabrication process was also explored. Characteristics were then compared to the control and mechanical characteristics of different human body part tissue. Nanosilica is the best filler to produce the best nanocomposite similarities with human tissue. We produced composites that approaching the properties of human internal tissues.

Military Standardization Handbook: Aircraft Refueling Handbook

DTIC Science & Technology

1992-10-20

explosive serious deterioration of rany rubber materials. It is as AVGAS. All aviation fuels must be handled therefore extremely important that only...additives are advised dissolved water a fuel will hold in parts per million to follow all instructions, wear gloves and aprons. (ppmt is approximately...FSII prevents the growth of contain one of these additives may cause abnormal Sfunguses and other microorganisrns which can wear or malfunctions or

VIEW OF JOHN ELDER OF JEANNETTE BADGE NO. 66. BREAKER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF JOHN ELDER OF JEANNETTE BADGE NO. 66. BREAKER FOR GENERAL GLASS COMPANY. TAKEN ON BREAKER FLOOR IN FRONT OF BUCK USED TO HOLD GLASS. WORK EQUIPMENT INCLUDES: HARD HAT, SAFETY GLASSES, PROTECTIVE SLEEVES, LEATHER APRON, GLOVES WITH RUBBER PADS ("METATARSALS") WITH OVER STEEL-TOED SHOES. - Chambers-McKee Window Glass Company, Furnace No. 2, Clay Avenue Extension, Jeannette, Westmoreland County, PA

Fast-adapting mechanoreceptors are important for force control in precision grip but not for sensorimotor memory.

PubMed

Park, Susanna B; Davare, Marco; Falla, Marika; Kennedy, William R; Selim, Mona M; Wendelschafer-Crabb, Gwen; Koltzenburg, Martin

2016-06-01

Sensory feedback from cutaneous mechanoreceptors in the fingertips is important in effective object manipulation, allowing appropriate scaling of grip and load forces during precision grip. However, the role of mechanoreceptor subtypes in these tasks remains incompletely understood. To address this issue, psychophysical tasks that may specifically assess function of type I fast-adapting (FAI) and slowly adapting (SAI) mechanoreceptors were used with object manipulation experiments to examine the regulation of grip force control in an experimental model of graded reduction in tactile sensitivity (healthy volunteers wearing 2 layers of latex gloves). With gloves, tactile sensitivity decreased significantly from 1.9 ± 0.4 to 12.3 ± 2.2 μm in the Bumps task assessing function of FAI afferents but not in a grating orientation task assessing SAI afferents (1.6 ± 0.1 to 1.8 ± 0.2 mm). Six axis force/torque sensors measured peak grip (PGF) and load (PLF) forces generated by the fingertips during a grip-lift task. With gloves there was a significant increase of PGF (14 ± 6%), PLF (17 ± 5%), and grip and load force rates (26 ± 8%, 20 ± 8%). A variable-weight series task was used to examine sensorimotor memory. There was a 20% increase in PGF when the lift of a light object was preceded by a heavy relative to a light object. This relationship was not significantly altered when lifting with gloves, suggesting that the addition of gloves did not change sensorimotor memory effects. We conclude that FAI fibers may be important for the online force scaling but not for the buildup of a sensorimotor memory. Copyright © 2016 the American Physiological Society.

Latex Clearing Protein (Lcp) of Streptomyces sp. Strain K30 Is a b-Type Cytochrome and Differs from Rubber Oxygenase A (RoxA) in Its Biophysical Properties

PubMed Central

Birke, Jakob; Röther, Wolf

2015-01-01

Specific polyisoprene-cleaving activities of 1.5 U/mg and 4.6 U/mg were determined for purified Strep-tagged latex clearing protein (Lcp) of Streptomyces sp. strain K30 at 23°C and 37°C, respectively. Metal analysis revealed the presence of approximately one atom of iron per Lcp molecule. Copper, which had been identified in Lcp1VH2 of Gordonia polyisoprenivorans previously, was below the detection limit in LcpK30. Heme was identified as a cofactor in purified LcpK30 by (i) detection of characteristic α-, β-, and γ (Soret)-bands at 562 nm, 532 nm, and 430 nm in the visible spectrum after chemical reduction, (ii) detection of an acetone-extractable porphyrin molecule, (iii) determination of a heme b-type-specific absorption maximum (556 nm) after chemical conversion of the heme group to a bipyridyl-heme complex, and (iv) detection of a b-heme-specific m/z value of 616.2 via mass spectrometry. Spectroscopic analysis showed that purified Lcp as isolated contains an oxidized heme-Fe3+ that is free of bound dioxygen. This is in contrast to the rubber oxygenase RoxA, a c-type heme-containing polyisoprene-cleaving enzyme present in Gram-negative rubber degraders, in which the covalently bound heme firmly binds a dioxygen molecule. LcpK30 also differed from RoxA in the lengths of the rubber degradation cleavage products and in having a higher melting point of 61.5°C (RoxA, 54.3°C). In summary, RoxA and Lcp both are equipped with a heme cofactor and catalyze an oxidative C-C cleavage reaction but differ in the heme subgroup type and in several biochemical and biophysical properties. These findings suggest differences in the catalytic reaction mechanisms. PMID:25819959

Subcellular proteome profiles of different latex fractions revealed washed solutions from rubber particles contain crucial enzymes for natural rubber biosynthesis.

PubMed

Wang, Dan; Sun, Yong; Chang, Lili; Tong, Zheng; Xie, Quanliang; Jin, Xiang; Zhu, Liping; He, Peng; Li, Hongbin; Wang, Xuchu

2018-06-30

Rubber particle (RP) is a specific organelle for natural rubber biosynthesis (NRB) and storage in rubber tree Hevea brasiliensis. NRB is processed by RP membrane-localized proteins, which were traditionally purified by repeated washing. However, we noticed many proteins in the discarded washing solutions (WS) from RP. Here, we compared the proteome profiles of WS, C-serum (CS) and RP by 2-DE, and identified 233 abundant proteins from WS by mass spectrometry. Many spots on 2-DE gels were identified as different protein species. We further performed shotgun analysis of CS, WS and RP and identified 1837, 1799 and 1020 unique proteins, respectively. Together with 2-DE, we finally identified 1825 proteins from WS, 246 were WS-specific. These WS-specific proteins were annotated in Gene Ontology, indicating most abundant pathways are organic substance metabolic process, protein degradation, primary metabolic process, and energy metabolism. Protein-protein interaction analysis revealed these WS-specific proteins are mainly involved in ribosomal metabolism, proteasome system, vacuolar protein sorting and endocytosis. Label free and Western blotting revealed many WS-specific proteins and protein complexes are crucial for NRB initiation. These findings not only deepen our understanding of WS proteome, but also provide new evidences on the roles of RP membrane proteins in NRB. Natural rubber is stored in rubber particle from the rubber tree. Rubber particles were traditionally purified by repeated washing, but many proteins were identified from the washing solutions (WS). We obtained the first visualization proteome profiles with 1825 proteins from WS, including 246 WS-specific ones. These WS proteins contain almost all enzymes for polyisoprene initiation and may play important roles in rubber biosynthesis. Copyright © 2018 Elsevier B.V. All rights reserved.

Split-Ring Resonator-Based Strain Sensor on Flexible Substrates for Glaucoma Detection

NASA Astrophysics Data System (ADS)

Ekinci, Gizem; Deniz Yalcinkaya, Arda; Dundar, Gunhan; Torun, Hamdi

2016-10-01

This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a contact lens. Silver conductive paint is to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas and the characteristics of devices with different curvature profiles are obtained. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is calculated as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The results indicate that the demonstrated device is suitable for glaucoma diagnosis.

Explosive Ordnance Disposal (EOD) Ensembles: Biophysical Characteristics and Predicted Work Times With and Without Chemical Protection and Active Cooling Systems

DTIC Science & Technology

2015-04-29

socks), white cotton glove liners , butyl rubber overboots, and self-contained breathing apparatus (SCBA) with air tank. Configuration 3: EOD suit...0073492 SCBA, CBRN, HP 60 Min Carbon DB, ZST, Case, VAS CON - CF Harness and Tank N/A 4240-20-A0F4879 Cylinder , Air Carbon HP 60 Minute - CF N/A 8120-20-007-3487 19

Carbon Nanofiber versus Graphene‐Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin

PubMed Central

Dussoni, Simeone; Ceseracciu, Luca; Maggiali, Marco; Natale, Lorenzo; Metta, Giorgio; Athanassiou, Athanassia

2017-01-01

Abstract Stretchable capacitive devices are instrumental for new‐generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple‐step replication. In this study, fabrication of a reliable elongating parallel‐plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq−1). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs‐based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces. PMID:29619306

Carbon Nanofiber versus Graphene-Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin.

PubMed

Cataldi, Pietro; Dussoni, Simeone; Ceseracciu, Luca; Maggiali, Marco; Natale, Lorenzo; Metta, Giorgio; Athanassiou, Athanassia; Bayer, Ilker S

2018-02-01

Stretchable capacitive devices are instrumental for new-generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple-step replication. In this study, fabrication of a reliable elongating parallel-plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq -1 ). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs-based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.

Deproteinised natural rubber latex grafted poly(dimethylaminoethyl methacrylate) - poly(vinyl alcohol) blend membranes: Synthesis, properties and application.

PubMed

Jayadevan, Janisha; Alex, Rosamma; Gopalakrishnapanicker, Unnikrishnan

2018-02-01

Natural rubber latex was initially deproteinised (DNRL) and then subjected to physicochemical modifications to make high functional membranes for drug delivery applications. Initially, DNRL was prepared by incubating with urea, sodiumdodecylsulphate and acetone followed by centrifugation. The deproteinisation was confirmed by CHN analysis. The DNRL was then chemically modified by grafting (dimethylaminoethyl methacrylate) onto NR particles by using a redox initiator system viz; cumene hydroperoxide/tetraethylenepentamine, followed by dialysis for purification. The grafting was confirmed by dynamic light scattering, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafted system was blended with a hydrophilic adhesive polymer PVA and casted into membranes. The membranes after blending showed enhanced mechanical properties with a threshold concentration of PVA. The moisture uptake, swelling and water contact angle experiments indicated an increased hydrophilicity with an increased PVA content in the blend membranes. The grafted DNRL possessed significant antibacterial property which has been found to be retained in the blended form. A notable decrease in cytotoxicity was observed for the modified DNRL membranes than the bare DNRL membranes. The in-vitro drug release studies using rhodamine B as a model drug, confirmed the utility of the prepared membranes to function as a drug delivery matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and characterization of potato starch nanocrystal reinforced natural rubber nanocomposites.

PubMed

Rajisha, K R; Maria, H J; Pothan, L A; Ahmad, Zakiah; Thomas, S

2014-06-01

Potato starch nanocrystals were found to serve as an effective reinforcing agent for natural rubber (NR). Starch nanocrystals were obtained by the sulfuric acid hydrolysis of potato starch granules. After mixing the latex and the starch nanocrystals, the resulting aqueous suspension was cast into film by solvent evaporation method. The composite samples were successfully prepared by varying filler loadings, using a colloidal suspension of starch nanocrystals and NR latex. The morphology of the nanocomposite prepared was analyzed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM analysis revealed the size and shape of the crystal and their homogeneous dispersion in the composites. The crystallinity of the nanocomposites was studied using XRD analysis which indicated an overall increase in crystallinity with filler content. The mechanical properties of the nanocomposites such as stress-strain behavior, tensile strength, tensile modulus and elongation at break were measured according to ASTM standards. The tensile strength and modulus of the composites were found to improve tremendously with increasing nanocrystal content. This dramatic increase observed can be attributed to the formation of starch nanocrystal network. This network immobilizes the polymer chains leading to an increase in the modulus and other mechanical properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of wound healing treated with latex derived from rubber trees and Aloe Vera extract in rats.

PubMed

Brandão, Marcelo Luiz; Reis, Paulo Roberto Melo; Araújo, Lilhian Alves de; Araújo, Ana Carolina Vicente; Santos, Maisa Helena de Abreu Silva; Miguel, Marina Pacheco

2016-09-01

To compare the use of latex derivative and Aloe vera extract to wound healing. Twenty one rats were randomly divided into three groups and each one had a wound made by incision. The treatment consisted in: derivative of latex (GL), Aloe vera extract (GA) and saline solution (GC). The wound area was measured on the 7th, 14th and 21st days and macroscopic and microscopic evaluation were done. The comparison between the measurements of the wounds presented statistical difference in GC and GA from the 7th day of evaluation and GL from the 14th day. The extent of the wound was significantly smaller by the 7th day in GL. Histologically, in GL, the neovascularization was significant on the 7th, 14th and 21st days. On the 21st day the scar was large and little mature. In GA and GC, the findings were similar on the 7th, 14th and 21st days with a slight better organization of skin and collagen on the 21st in GA. Statistical analysis did not allow for the definition of the best topical agent. The latex had the highest angiogenesis, but a possible foreign body granuloma. Aloe vera has revealed a healing process adequated temporally in histology.

Preparation of Self-Assembled Chitin Nanofiber-Natural Rubber Composite Sheets and Porous Materials

PubMed Central

Kawano, Akito; Yamamoto, Kazuya

2017-01-01

We previously reported the preparation of a self-assembled chitin nanofiber (CNF) film via regeneration from an ion gel with an ionic liquid, followed by sonication and filtration. Based on the finding that CNFs were redispersed in a mixture of the film with ammonia aqueous solution (aq.), in this study, CNF-natural rubber (NR) composite sheets were fabricated by mixing redispersed CNF with NR latex stabilized by ammonia, followed by drying under reduced pressure. Tensile testing of the sheets indicated the reinforcing effect of CNFs. Further, CNF-NR composite porous materials were fabricated by evaporating ammonia from the CNF-NR dispersion, followed by lyophilization. The mechanism for the formation of porous structures was evaluated. PMID:28671578

Morpho-Molecular Characterization of Two Ampelomyces spp. (Pleosporales) Strains Mycoparasites of Powdery Mildew of Hevea brasiliensis.

PubMed

Liyanage, Kapila K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

2018-01-01

Powdery mildew disease of rubber affects immature green leaves, buds, inflorescences, and other immature tissues of rubber trees, resulting in up to 45% losses in rubber latex yield worldwide. The disease is often controlled by dusting the diseased plants with powdered sulfur, which can have long-term negative effects on the environment. Therefore, it is necessary to search for alternative and environmentally friendly control methods for this disease. This study aimed to identify mycoparasites associated with rubber powdery mildew species, and characterize them on the basis of morpho-molecular characteristics and phylogenetic analyses of ITS rDNA regions. We observed that the Ampelomyces fungus parasitizes rubber powdery mildew, and eventually destroys it. Furthermore, on the basis of phylogenetic analyses and morphological characteristics we confirmed that the Ampelomyces mycoparasite isolated from rubber powdery mildew is closely related to other mycohost taxa in the Erysiphe genus. A total of 73 (71 retrieved from GenBank and two obtained from fresh collections of rubber powdery mildew fungi) Ampelomyces spp. were analyzed using ITS rDNA sequences and 153 polymorphic sites were identified through haplotypic analyses. A total of 28 haplotypes (H1-H28) were identified to have a complex network of mutation events. The results from phylogenetic tree constructed on the basis of maximum likelihood analyses, and the haplotype network tree revealed similar relationships of clustering pattern. This work presents the first report on morpho-molecular characterization of Ampelomyces species that are mycoparasites of powdery mildew of Hevea brasiliensis .

Molecular cloning and immunoglobulin E reactivity of a natural rubber latex lecithinase homologue, the major allergenic component of Hev b 4.

PubMed

Sunderasan, E; Bahari, A; Arif, S A M; Zainal, Z; Hamilton, R G; Yeang, H Y

2005-11-01

Hev b 4 is an allergenic natural rubber latex (NRL) protein complex that is reactive in skin prick tests and in vitro immunoassays. On SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Hev b 4 is discerned predominantly at 53-55 kDa together with a 57 kDa minor component previously identified as a cyanogenic glucosidase. Of the 13 NRL allergens recognized by the International Union of Immunological Societies, the 53-55 kDa Hev b 4 major protein is the only candidate that lacks complete cDNA and protein sequence information. We sought to clone the transcript encoding the Hev b 4 major protein, and characterize the native protein and its recombinant form in relation to IgE binding. The 5'/3' rapid amplification of cDNA ends method was employed to obtain the complete cDNA of the Hev b 4 major protein. A recombinant form of the protein was over-expressed in Escherichia coli. The native Hev b 4 major protein was deglycosylated by trifluoromethane sulphonic acid. Western immunoblots of the native, deglycosylated and recombinant proteins were performed using both polyclonal antibodies and sera from latex-allergic patients. The cDNA encoding the Hev b 4 major protein was cloned. Its open reading frame matched lecithinases in the conserved domain database and contained 10 predicted glycosylation sites. Detection of glycans on the Hev b 4 lecithinase homologue confirmed it to be a glycoprotein. The deglycosylated lecithinase homologue was discerned at 40 kDa on SDS-PAGE, this being comparable to the 38.53 kDa mass predicted by its cDNA. Deglycosylation of the lecithinase homologue resulted in the loss of IgE recognition, although reactivity to polyclonal rabbit anti-Hev b 4 was retained. IgE from latex-allergic patients also failed to recognize the non-glycosylated E. coli recombinant lecithinase homologue. The IgE epitopes of the Hev b 4 lecithinase homologue reside mainly in its carbohydrate moiety, which also account for the discrepancy between the observed molecular weight of the protein and the value calculated from its cDNA.

Nanocelluloses from jute fibers and their nanocomposites with natural rubber: Preparation and characterization.

PubMed

Thomas, Martin George; Abraham, Eldho; Jyotishkumar, P; Maria, Hanna J; Pothen, Laly A; Thomas, Sabu

2015-11-01

Nanocellulose fibers having an average diameter of 50nm were isolated from raw jute fibers by steam explosion process. The isolation of nanocellulose from jute fibers by this extraction process is proved by SEM, XRD, FTIR, birefringence and TEM characterizations. This nanocellulose was used as the reinforcing agent in natural rubber (NR) latex along with crosslinking agents to prepare crosslinked nanocomposite films. The effects of nanocellulose loading on the morphology and mechanics of the nanocomposites have been carefully analyzed. Significant improvements in the Young's modulus and tensile strength of the nanocomposite were observed because of the reinforcing ability of the nanocellulose in the rubber matrix. A mechanism is suggested for the formation of the Zn-cellulose complex. The three-dimensional network of cellulose nanofibers (cellulose/cellulose network and Zn/cellulose network) in the NR matrix plays a major role in improving the properties of the crosslinked nanocomposites. Copyright © 2015 Elsevier B.V. All rights reserved.

Operation Desert Shield Lessons Learned

DTIC Science & Technology

1991-01-01

MRE, T and B rations) issued in Army Mess Halls. (2) Peelable fruits, i.e., oranges and bananas , apples, and pears after being peeled and washed...every day, they cannot get a good seal on their protective masks and are likely to become casualties in the event of a chemical attack. LESSON...liquid mustard agent is imminent. (2) Find clean areas to get relief from wearing rubber gloves and boots before softening of the hands and feet

Identification of stand age in rubber plantations using time series Landsat and PALSAR-2 data

NASA Astrophysics Data System (ADS)

Chen, B.; Wu, Z.; Xiao, X.; Li, X.; Ma, J.; Lan, G.; Yang, C.; Xie, G.; Dong, J.; Qin, Y.

2016-12-01

Stand age of rubber plantation is vital for optimal plantation management such as fertilization, prediction of latex yield and timber production. It is also an important variable for biomass estimation and determining the distribution of carbon pools and fluxes in rubber plantation ecosystem. Benefit from the traits of large coverage, high speed, and low-cost, satellite remote sensing techniques have been serviced as a major approach to map acreage and stand age of forest and plantations. Despite a number of studies working on acreage and stand age mapping, the stand age information of rubber plantation is still poorly available at regional scale. In this study, the 25-m cloud-free Phased Array type L-band Synthetic Aperture Radar 2 (PALSAR-2) mosaic product, together with the 30-m time series images of Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI), were used to map stand age of rubber plantation in China under Google Earth Engine computing platform. Rubber plantation in 2015 were first identified by structural information in PALSAR-2 and phenological and spectral signatures (deciduous, rapid change of canopies during rubber defoliation and foliation periods, and dense canopy in growing season) that derived from time series Landsat ETM+/OLI images. Based on the resultant rubber plantation map, we then successfully identified the stand age of rubber plantation using land cover transfer information during rubber seeding cultivation period, specifically, by yearly composited Land Surface Water Index (LSWI) of Landsat TM/ETM+/OLI images since 1985. The estimated stand age has very high accuracy with Root Square Mean Error (RMSE) less than 2 years. The resultant rubber stand age information are likely to be useful for sustainable plantation management and ecological assessment, and the methodology can be extendable for applications in other regions.

Plastic condoms.

PubMed

1968-01-01

Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly mandrel. The condom is then ready for packaging, either on automatic equipment or manually into small envelopes of highly polished paper. Although their present design is based on a heat-sealed blank, it may be possible shortly to manufacture plastic condoms on the same principle as rubber ones. A dipping process would be used, but with less sophisticated technology and with higher outputs per increment of capital investment. The present equipment used to make plastic condoms cost about 3,000 for one stamping machine and 22 assembly and testing machines. On a three shift per day, 300-day working year, it is possible, with experienced workers, to make 100,000 gross of plastic condoms for each manufacturing unit annually. As the technology is refined, the output should improve significantly.

Combined Screw-Cap and Rubber-Stopper Closure for Hungate Tubes (Pre-reduced Anaerobically Sterilized Roll Tubes and Liquid Media)

PubMed Central

Attebery, H. R.; Finegold, S. M.

1969-01-01

A double-closured method introduced for Hungate tubes eliminates clamps or special racks to hold the rubber stoppers in place while the tubes are being processed. The system prevents stoppers from being dislodged by gas-producing anaerobes and keeps the stoppers sterile so that the closed system of transfer can be conveniently utilized. Open and closed systems for handling a gas-producing anaerobe were compared. Ten tubes containing Clostridium perfringens were opened; the organism was detected in the air by use of an impingement collector. The gloved hand of the operator also revealed the test organism. A similar trial with culture material removed by the closed system (syringe transfer) resulted in no detectable contamination of the environment. Images PMID:4312921

Combined screw-cap and rubber-stopper closure for Hungate tubes (pre-reduced anaerobically sterilized roll tubes and liquid media).

PubMed

Attebery, H R; Finegold, S M

1969-10-01

A double-closured method introduced for Hungate tubes eliminates clamps or special racks to hold the rubber stoppers in place while the tubes are being processed. The system prevents stoppers from being dislodged by gas-producing anaerobes and keeps the stoppers sterile so that the closed system of transfer can be conveniently utilized. Open and closed systems for handling a gas-producing anaerobe were compared. Ten tubes containing Clostridium perfringens were opened; the organism was detected in the air by use of an impingement collector. The gloved hand of the operator also revealed the test organism. A similar trial with culture material removed by the closed system (syringe transfer) resulted in no detectable contamination of the environment.

Morpho-Molecular Characterization of Two Ampelomyces spp. (Pleosporales) Strains Mycoparasites of Powdery Mildew of Hevea brasiliensis

PubMed Central

Liyanage, Kapila K.; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E.; Karunarathna, Samantha C.; Xu, Jianchu; Hyde, Kevin D.

2018-01-01

Powdery mildew disease of rubber affects immature green leaves, buds, inflorescences, and other immature tissues of rubber trees, resulting in up to 45% losses in rubber latex yield worldwide. The disease is often controlled by dusting the diseased plants with powdered sulfur, which can have long-term negative effects on the environment. Therefore, it is necessary to search for alternative and environmentally friendly control methods for this disease. This study aimed to identify mycoparasites associated with rubber powdery mildew species, and characterize them on the basis of morpho-molecular characteristics and phylogenetic analyses of ITS rDNA regions. We observed that the Ampelomyces fungus parasitizes rubber powdery mildew, and eventually destroys it. Furthermore, on the basis of phylogenetic analyses and morphological characteristics we confirmed that the Ampelomyces mycoparasite isolated from rubber powdery mildew is closely related to other mycohost taxa in the Erysiphe genus. A total of 73 (71 retrieved from GenBank and two obtained from fresh collections of rubber powdery mildew fungi) Ampelomyces spp. were analyzed using ITS rDNA sequences and 153 polymorphic sites were identified through haplotypic analyses. A total of 28 haplotypes (H1–H28) were identified to have a complex network of mutation events. The results from phylogenetic tree constructed on the basis of maximum likelihood analyses, and the haplotype network tree revealed similar relationships of clustering pattern. This work presents the first report on morpho-molecular characterization of Ampelomyces species that are mycoparasites of powdery mildew of Hevea brasiliensis. PMID:29403464

Respiratory and skin effects of exposure to wood dust from the rubber tree Hevea brasiliensis.

PubMed

Sripaiboonkij, P; Phanprasit, W; Jaakkola, M S

2009-07-01

Potential health effects related to wood dust from the rubber tree, which produces natural rubber latex, have not been previously investigated. The main aim of this study was to investigate the relations of rubber tree dust exposure to respiratory and skin symptoms, asthma and lung function. A cross-sectional study was conducted among 103 workers (response rate 89%) in a rubber tree furniture factory and 76 office workers (73%) in four factories in Thailand. All participants answered a questionnaire and performed spirometry. Inhalable dust levels were measured in different work areas. Factory workers showed increased risk of wheezing, nasal symptoms and asthma compared to office workers. There was a dose-dependent increase in wheeze and skin symptoms in relation to dust level. Significantly increased risks of nasal symptoms (adj OR 3.67, 95% CI 1.45 to 9.28) and asthma (8.41, 1.06 to 66.60) were detected in the low exposure category. Workers exposed to ethyl cyanoacrylate glue had significantly increased risk of cough, breathlessness and nasal symptoms. There was dose-dependent reduction in spirometric lung function with wood dust level. This study provides new evidence that workers exposed to wood dust from the rubber tree experience increased risk of nasal symptoms, wheeze, asthma and skin symptoms and have reduced spirometric lung function. Exposure to cyanoacrylate is related to significantly increased respiratory symptoms. Results suggest that the furniture industry using rubber tree wood should implement appropriate exposure control measures to reduce wood dust exposure and cyanoacrylate glue exposure to protect their employees.

Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz

PubMed Central

2010-01-01

Background Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz. Results We established a method for the purification of rubber particles - the active sites of rubber biosynthesis - from T. koksaghyz latex. Photon correlation spectroscopy and transmission electron microscopy revealed an average particle size of 320 nm, and 13C nuclear magnetic resonance (NMR) spectroscopy confirmed that isolated rubber particles contain poly(cis-1,4-isoprene) with a purity >95%. Size exclusion chromatography indicated that the weight average molecular mass (w) of T. koksaghyz natural rubber is 4,000-5,000 kDa. Rubber particles showed rubber transferase activity of 0.2 pmol min-1 mg-1. Ex vivo rubber biosynthesis experiments resulted in a skewed unimodal distribution of [1-14C]isopentenyl pyrophosphate (IPP) incorporation at a w of 2,500 kDa. Characterization of recently isolated cis-prenyltransferases (CPTs) from T. koksaghyz revealed that these enzymes are associated with rubber particles and are able to produce long-chain polyprenols in yeast. Conclusions T. koksaghyz rubber particles are similar to those described for H. brasiliensis. They contain very pure, high molecular mass poly(cis-1,4-isoprene) and the chain elongation process can be studied ex vivo. Because of their localization on rubber particles and their activity in yeast, we propose that the recently described T. koksaghyz CPTs are the major rubber chain elongating enzymes in this species. T. koksaghyz is amenable to genetic analysis and modification, and therefore could be used as a model species for the investigation and comparison of rubber biosynthesis. PMID:20170509

Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi.

PubMed

Liyanage, K K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

2017-04-01

Powdery mildew is a fungal disease that infects a wide range of plants, including rubber trees, which results in a reduction of latex yields of up to 45%. The causal agent of powdery mildew of rubber was first described as Oidium heveae, but later morpho-molecular research suggested that in the past, O. heveae has been confused with Erysiphe quercicola. However, it is still under debate whether the causal agent should be classified as a species of the genus Erysiphe emend. or Golovinomyces and Podosphaera, respectively. Therefore, the aim of this study was to undertake the morpho-molecular characterization of powdery mildew species associated with rubber trees, thus resolving these taxonomic issues. Morphological observation under light and scanning electron microscopes (SEM) clearly identified two morphotypes of the rubber powdery mildew. With the support of morphological and phylogenetic data, one of the two morphotypes was identified as the asexual morph of E. quercicola, while the second morphotype is still insufficiently known and according to the morphological results obtained we assume that it might belong to the genus Golovinomyces. More collections and additional molecular data are required for final conclusions regarding the exact taxonomic position of the second morphotype of rubber powdery mildew and its relation to the name O. heveae. The haplotype analysis identified eight haplotype groups of E. quercicola indicating the high genetic diversity of the species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors

PubMed Central

Yap, Hong Kai; Lim, Jeong Hoon; Nasrallah, Fatima; Yeow, Chen-Hua

2017-01-01

Various robotic exoskeletons have been proposed for hand function assistance during activities of daily living (ADL) of stroke survivors. However, traditional exoskeletons involve the use of complex rigid systems that impede the natural movement of joints, and thus reduce the wearability and cause discomfort to the user. The objective of this paper is to design and evaluate a soft robotic glove that is able to provide hand function assistance using fabric-reinforced soft pneumatic actuators. These actuators are made of silicone rubber which has an elastic modulus similar to human tissues. Thus, they are intrinsically soft and compliant. Upon air pressurization, they are able to support finger range of motion (ROM) and generate the desired actuation of the finger joints. In this work, the soft actuators were characterized in terms of their blocked tip force, normal and frictional grip force outputs. Combining the soft actuators and flexible textile materials, a soft robotic glove was developed for grasping assistance during ADL for stroke survivors. The glove was evaluated on five healthy participants for its assisted ROM and grip strength. Pilot test was performed in two stroke survivors to evaluate the efficacy of the glove in assisting functional grasping activities. Our results demonstrated that the actuators designed in this study could generate desired force output at a low air pressure. The glove had a high kinematic transparency and did not affect the active ROM of the finger joints when it was being worn by the participants. With the assistance of the glove, the participants were able to perform grasping actions with sufficient assisted ROM and grip strength, without any voluntary effort. Additionally, pilot test on stroke survivors demonstrated that the patient's grasping performance improved with the presence and assistance of the glove. Patient feedback questionnaires also showed high level of patient satisfaction and comfort. In conclusion, this paper has demonstrated the possibility of using soft wearable exoskeletons that are more wearable, lightweight, and suitable to be used on a daily basis for hand function assistance of stroke survivors during activities of daily living. PMID:29062267

Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics.

PubMed

Lee, Jaehong; Kwon, Hyukho; Seo, Jungmok; Shin, Sera; Koo, Ja Hoon; Pang, Changhyun; Son, Seungbae; Kim, Jae Hyung; Jang, Yong Hoon; Kim, Dae Eun; Lee, Taeyoon

2015-04-17

A flexible and sensitive textile-based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very fast response time, and high stability, compared with previous textile-based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes that can control machines wirelessly as human-machine interfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of Transfer of Salmonella from Citrus Fruits to Peel, Edible Portion, and Gloved Hands during Hand Peeling.

PubMed

Jung, Jiin; Friedrich, Loretta M; Danyluk, Michelle D; Schaffner, Donald W

2017-06-01

Although studies have quantified bacterial transfer between hands and various materials, cross-contamination between the surface of fresh citrus fruit and the edible portions during hand peeling has not been reported. This study quantifies transfer of Salmonella to the edible portion of citrus fruit from a contaminated peel during hand peeling. Citrus fruits used for this study were Citrus sinensis (sweet orange) cultivars 'Valencia' and 'Navel', Citrus unshiu (Satsuma mandarins), Citrus reticulata × Citrus paradisi ('Minneola' tangelo or 'Honeybell'), and C. paradisi (grapefruit) cultivar 'Marsh'. An avirulent Salmonella Typhimurium LT2 (ATCC 700720) resistant to rifampin was used for all experiments. The inoculum containing approximately 9 log CFU/mL (50 μL) was spot inoculated onto the equator, stem, or styler of each fruit and allowed to dry for 24 h. Six volunteers put on single-use latex gloves and peeled inoculated fruit. Peel, edible fruit portion, and gloves were collected and enumerated separately. Three replicates of the study were performed in which each volunteer peeled two inoculated fruit of each variety (n = 36 fruit per variety). Cross-contamination from contaminated surface of citrus fruits to edible portion or gloved hands during peeling was affected by inoculation sites. Average Salmonella transfer to the edible portion ranged from 0.16% (Valencia inoculated at the equator) to 5.41% (navel inoculated at the stem). Average Salmonella transfer to gloved hands ranged from 0.41% (grapefruit inoculated at the stem) to 8.97% (navel inoculated at the stem). Most Salmonella remained on the peel of citrus fruits. The average level of Salmonella remaining on the peel ranged from 5.37% (Minneola inoculated at the equator) to 66.3% (Satsuma inoculated at the styler). When grapefruit was inoculated, the Salmonella that remained on the peel showed a bimodal pattern in which some individuals left almost all Salmonella on the peel, while others left substantially less.

[Modified gloving technique for vacuum therapy in the hand].

PubMed

Polykandriotis, E; Kneser, U; Kopp, J; Horch, R E

2006-04-01

During the last 10 years sub-atmospheric pressure dressings (Topical Negative Pressure Therapy = TNP) has become a well accepted standard therapeutic modality in the management of acute and chronic wounds. However, in the hand and the fingers TNP treatment is not as an established method as elsewhere in the body. This is mostly due to difficulties in the technique of sealing wounds near the interdigital folds, especially when the interdigital folds are affected themselves. Over a period of 36 months we treated 9 extensive open wounds of the hand with the TNP dressing procedure. To optimize the effective sealing procedure several methods of closure were applied: sterile vinyl gloves, split V.A.C. gel-straps and the "Sandwich"-principle. In all cases we were able to achieve a tight vacuum sealing with the use of our vinyl or latex free surgical glove as an aid to cover the interdigital spaces. There was a rapid and complete remission of the symptoms in terms of edema, redness, tenderness and range of motion. The indication spectrum encompassed infection control, temporary coverage of exposed bone or tendons, intermittent irrigation with local antiseptics as well as wound preconditioning before skin grafting or flap coverage. For the definite closure or coverage a second operation was necessary in all cases. The TNP-dressing can be securely achieved even in wounds encompassing the interdigital folds or adjacent to the in digital spaces with a modified surgical gloving technique to aid the standard sealing foil. It is a suitable principle for the management of severe hand infections with a reduction of clinical symptoms, reduction of the frequency of dressing changes compared to open approaches and a significant amelioration in the quality of life both for patients and health care personnel.

Experimental comparison of manufacturing techniques of toughened and nanoreinforced polyamides

NASA Astrophysics Data System (ADS)

Siengchin, S.; Bergmann, C.; Dangtungee, R.

2011-11-01

Composites consisting of polyamide-6 (PA-6), nitrile rubber (NBR), and sodium fluorohectorite (FH) or alumina silicate (Sungloss; SG) were produced by different techniques with latex precompounding. Their tensile and thermomechanical properties were determined by using tensile tests and a dynamic-mechanical analysis, performed at various temperatures. The PA-6/NBR composite systems produced by the direct melt compounding outperformed those obtained by using the masterbatch technique with respect to the strength and ductility, but the latter ones had a higher storage modulus.

A respiratory mask for resting and exercising dogs.

PubMed

Stavert, D M; Reischl, P; O'Loughlin, B J

1982-02-01

A respiratory face mask has been developed for use with unsedated beagles trained to run on a treadmill. The latex rubber mask, shaped to fit the animal's muzzle, incorporates two modified, commercially available, pulmonary valves for separating inspiratory and expiratory flows. The mask has a dead space of 30 cm3 and a flow resistance below 1 cmH2O . 1(-1) . s. The flexible mask is used to measure breath-by-breath respiratory variables over extended periods of time during rest and exercise.

Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

PubMed

Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

2015-10-05

Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pattern of occupational allergic dermatitis in the Dermatology Clinic, Hospital Kuala Lumpur.

PubMed

Rohna, R; Ganesapillai, T; Salbiah, D; Zaiton, I

1999-03-01

A two years retrospective analysis of patients diagnosed as contact allergic dermatitis with positive patch test attending the Dermatology clinic was performed. Of the 346 patients with a positive patch test, 14% had occupational dermatitis. This condition affected mainly young and inexperienced workers. An inverse relationship was seen between age and prevalence of occupational allergic dermatitis. Allergic hand dermatitis was the commonest presentation in occupational allergic dermatitis. This was followed by dermatitis of the exposed skin (face, neck, hands and forearms). The common sensitising agents identified were rubber chemicals and nickel. The two main groups at risk were factory workers and medical personnel. The common allergens found in factory workers were epoxy resin, pewter, nickel and rubber chemicals. Exposure dermatitis occurred in patients working in the pewter industry. Two thirds of medical personnel with hand dermatitis were allergic to rubber gloves. One year follow up after patch testing showed that 19% of patients still suffered from chronic dermatitis. Dermatitis improved in 34% of patients. Forty-seven percent were cured and stopped attending the clinic after patch testing and adequate counselling.

Effect of electric field induced alignment and dispersion of functionalized carbon nanotubes on properties of natural rubber

NASA Astrophysics Data System (ADS)

Gao, Jiangshan; He, Yan; Gong, Xiubin

2018-06-01

The original equipment and method for orienting multi-walled carbon nanotubes (MWCNTs) in natural rubber (NR) by alternating current (AC) electric field were reported in the present study. MWCNTs with various volume fractions were dispersed in the mixture latex which composed of natural rubber, additives and methylbenzene. The application of AC electric field during nanocomposites curing process was used to induce the formation of aligned conductive nanotube networks between the electrodes. The aligned MWCNTs in the composites have a better orientation performance and dispersion quality than these of random MWCNTs by analyzing TEM and SEM images. The effects of MWCNTs anisotropy on thermal conductivity, dielectric properties, and dynamic mechanical properties of NR were studied. The mean value of thermal conductivity of composites loading with aligned MWCNTs was 8.67% higher than that of composites with random MWCNTs due to the anisotropy of aligned MWCNTs. The compounds with aligned MWCNTs possessed low dielectric constant, loss tangents and conductivity, namely a good insulativity. The compounds loading with aligned MWCNTs had lower loss modulus and better dynamic mechanical properties than those with random MWCNTs. This method can make full use of the high thermal conductivity of MWCNTs axis, and expand the application areas of natural rubber like conducting heat in a certain direction with a high efficiency.

Super-Resolution Fluorescence Imaging of Spatial Organization of Proteins and Lipids in Natural Rubber.

PubMed

Wu, Jinrong; Qu, Wei; Huang, Guangsu; Wang, Siyuan; Huang, Cheng; Liu, Han

2017-06-12

Natural rubber (NR) with proteins and lipids has superior mechanical properties to its synthetic counterpart, polyisoprene rubber. However, it is a challenge to unravel the morphology of proteins and lipids. Here we used two-color stochastic optical reconstruction microscopy (STORM) to directly visualize the spatial organization of proteins and lipids in NR. We found that the proteins and lipids form an interdispersed stabilizing layer on the surface of NR latex particles. After drying, the proteins and lipids form aggregates of up to 300 nm in diameter. The aggregates physically interact with the terminal groups of polyisoprene chains, leading to the formation of a network, which contributes to the high elasticity and mechanical property of NR. If we remove proteins in NR, the large phospholipid aggregates disintegrate into small ones. However, it does not decompose the network but rather reduces the effective cross-linking density, thus the deproteinized NR is still elastic-like with decreased mechanical property. Removing both proteins and lipids wholly decomposes the network, thus, results in a liquid-like behavior of the rubber. The STORM measurements in this paper enable more insight into the structure-property relationship of NR, which also shows a great potential of STORM in studying the fine structure of polymeric materials and nanocomposites.

Extractive reserves in Brazilian Amazonia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fearnside, P.M

1989-06-01

In 1985 an opportunity arose for maintaining tracts of Amazonian forest under sustainable use. Brazil's National Council of Rubber Tappers and the Rural Worker's Union proposed the creation of a set of reserves of a new type, called extractive reserves. The first six are being established in one of the Brazilian states most threatened by deforestatation. The creation of extractive reserves grants legal protection to forest land traditionally used by rubber tappers, Brazil-nut gatherers, and other extractivists. The term extrativismo (extractivism) in Brazil refers to removing nontimber forest products, such as latex, resins, and nuts, without felling the trees. Approximatelymore » 30 products are collected for commercial sale. Many more types of forest materials are gathered, for example as food and medicines, for the extractivists' own use. The reserve proposal is attractive for several reasons related to social problems. It allows the rubber tappers to continue their livelihood rather than be expelled by deforestation. However, it is unlikely that sufficient land will be set aside as extractive reserves to employ all the tappers. Displaced rubber tappers already swell the ranks of urban slum dwellers in Brazil's Amazonian cities, and they have become refugees to continue their profession in the forests of neighboring countries, such as Bolivia.« less

Maintenance of influenza virus infectivity on the surfaces of personal protective equipment and clothing used in healthcare settings.

PubMed

Sakaguchi, Hiroko; Wada, Koji; Kajioka, Jitsuo; Watanabe, Mayumi; Nakano, Ryuichi; Hirose, Tatsuko; Ohta, Hiroshi; Aizawa, Yoshiharu

2010-11-01

The maintenance of infectivity of influenza viruses on the surfaces of personal protective equipment and clothing is an important factor in terms of controlling viral cross-infection in the environment and preventing contact infection. The aim of this study was to determine if laboratory-grown influenza A (H1N1) virus maintained infectivity on the surfaces of personal protective equipment and clothing used in healthcare settings. Influenza A virus (0.5 mL) was deposited on the surface of a rubber glove, an N95 particulate respirator, a surgical mask made of non-woven fabric, a gown made of Dupont Tyvek, a coated wooden desk, and stainless steel. Each sample was left for 1, 8, and 24 h, and hemagglutination (HA) and 50% tissue culture infective dose (TCID(50))/mL were measured. The HA titer of this influenza A virus did not decrease in any of the materials tested even after 24 h. The infectivity of influenza A virus measured by TCID(50) was maintained for 8 h on the surface of all materials, with the exception of the rubber glove for which virus infectivity was maintained for 24 h. Our results indicate that the replacement/renewal of personal protective equipment and clothing by healthcare professionals in cases of exposure to secretions and droplets containing viruses spread by patients is an appropriate procedure to prevent cross-infection.

Effects of tacky mat contamination on bond degradation for Chemlok/liner and NBR/liner bonds

NASA Technical Reports Server (NTRS)

Padilla, A. M.

1989-01-01

Tacky mats are placed by the rubber lay-up areas for the solid rocket motor segments. These mats dust off the shoes prior to entering the platform where the lay-up work is performed. The possibility exists that a tacky mat could be touched with gloved hands prior to handling the uncured nitride butadiene rubber (NBR). Tests were run to determine if NBR were accidentally touched would there be any degradation of the liner/NBR bond. The tacky mats were judged solely on the basis of bond degradation caused by either direct or indirect contamination. Test results all indicate that there was no notable NBR/Chemlok or liner/NBR bond degradation on samples that came into contact with the tacky mat material. Testing procedures are described. The tacky mat adhesive composition does not contain fluorocarbons or release agents that would affect bonding.

Personal Exposure to Inhalable Dust and the Specific Latex Aero-Allergen, Hev b6.02, in Latex Glove Manufacturing in Thailand

PubMed Central

Sanguanchaiyakrit, Nuthchyawach; Povey, Andrew C.; de Vocht, Frank

2014-01-01

Objectives: Latex product manufacturing is an important industry in south-east Asia but has the potential for considerable occupational exposure of workers to latex allergens. Although exposure to latex allergens can result in adverse health reactions, few studies to characterize this exposure have been conducted to date. This study therefore aimed to characterize current airborne inhalable dust and the specific allergen, Hev b 6.02, exposures in this industry in Thailand. Methods: Workers were recruited from three factories in the southern part of Thailand. Full-shift inhalable dust personal air sampling was conducted using IOM sampling heads equipped with polytetrafluoroethylene filters at a 2.0 l min−1 flowrate. After weighing to determine inhalable dust levels, filters were extracted and analysed for Hev b 6.02 using an enzyme immunometric assay. Results: Two hundred and seventy-five workers agreed to participate, resulting in a total of 292 measurements. Geometric mean (GM) personal exposure to inhalable dust was 0.88mg m–3, but individual exposures up to 12.34mg m–3 were measured. The pattern of exposure was similar across factories, with highest exposures in the stripping (GM 2.08–4.05mg m–3 for the 3 factories) and tumbling departments (1.11–2.17mg m–3). Within-worker (day-to-day) variability contributed 92% to total variability. The Hev b 6.02 exposure pattern was similar with time-weighted average GM exposure levels in the oldest factory ranging from 8.7mg m–3 in the laboratory to 30.2mg m–3 in the stripping department. In contrast to inhalable dust exposure, total exposure variability was primary driven by variability between workers (67%). Conclusions: Workers in these latex product factories get routinely exposed to measurable Hev b 6.02 levels, which may give rise to increased incidence of allergic symptoms and occupational asthma. Also, in this measurement campaign a 10mg m–3, but not 15mg m–3, occupational exposure limit for inhalable dust was occasionally exceeded. Highest Hev b 6.02 exposures were found in the stripping and tumbling departments, which would be natural targets for interventions aimed at reducing exposure. PMID:24569810

Personal exposure to inhalable dust and the specific latex aero-allergen, Hev b6.02, in latex glove manufacturing in Thailand.

PubMed

Sanguanchaiyakrit, Nuthchyawach; Povey, Andrew C; de Vocht, Frank

2014-06-01

Latex product manufacturing is an important industry in south-east Asia but has the potential for considerable occupational exposure of workers to latex allergens. Although exposure to latex allergens can result in adverse health reactions, few studies to characterize this exposure have been conducted to date. This study therefore aimed to characterize current airborne inhalable dust and the specific allergen, Hev b 6.02, exposures in this industry in Thailand. Workers were recruited from three factories in the southern part of Thailand. Full-shift inhalable dust personal air sampling was conducted using IOM sampling heads equipped with polytetrafluoroethylene filters at a 2.0 l min(-1) flowrate. After weighing to determine inhalable dust levels, filters were extracted and analysed for Hev b 6.02 using an enzyme immunometric assay. Two hundred and seventy-five workers agreed to participate, resulting in a total of 292 measurements. Geometric mean (GM) personal exposure to inhalable dust was 0.88 mg m(-3), but individual exposures up to 12.34 mg m(-3) were measured. The pattern of exposure was similar across factories, with highest exposures in the stripping (GM 2.08-4.05 mg m(-3) for the 3 factories) and tumbling departments (1.11-2.17 mg m(-3)). Within-worker (day-to-day) variability contributed 92% to total variability. The Hev b 6.02 exposure pattern was similar with time-weighted average GM exposure levels in the oldest factory ranging from 8.7 mg m(-3) in the laboratory to 30.2mg m(-3) in the stripping department. In contrast to inhalable dust exposure, total exposure variability was primary driven by variability between workers (67%). Workers in these latex product factories get routinely exposed to measurable Hev b 6.02 levels, which may give rise to increased incidence of allergic symptoms and occupational asthma. Also, in this measurement campaign a 10mg m(-3), but not 15 mg m(-3), occupational exposure limit for inhalable dust was occasionally exceeded. Highest Hev b 6.02 exposures were found in the stripping and tumbling departments, which would be natural targets for interventions aimed at reducing exposure. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Advising parents on washing babies' clothes.

PubMed

Scowen, P

1996-01-01

Detergents and other laundry products are generally effective and safe for all the family, but use carefully according to the maker's instructions and keep out of the reach of children. Rinse thoroughly to remove detergent residue from fabrics. If handwashing clothes, dissolve detergent before immersing hands. Wear rubber gloves if possible. Wash, rinse and dry hands thoroughly after contact with detergent. If a baby or parent has eczema, it may be necessary to try different products to see which one the client can tolerate. A non-perfumed, non-enzyme product may be found less irritating.

Contact allergy to an epoxy reactive diluent: 1,4-butanediol diglycidyl ether.

PubMed

Jolanki, R; Estlander, T; Kanerva, L

1987-02-01

3 female workers in a brush factory developed contact allergy from a 2-component epoxy glue containing epoxy resin (37% w/w), reactive diluents: i.e., 1,4-butanediol diglycidyl ether (BDDGE) 3%, glycidyl ethers of aliphatic alcohols (Epoxide 8) 0.03% and phenyl glycidyl ether (PGE) 0.01%; and inert fillers. All 3 patients were positive to the resin component of the glue and to BDDGE, indicating that BDDGE was the main allergen. 2 of the patients reacted to PGE, but none to the 3rd reactive diluent (Epoxide 8) in the glue. 2 of the patients did not react to epoxy resin, indicating that BDDGE may be an even stronger sensitizer in humans than epoxy resin, and that it does not cross-react with epoxy resins. Permeation studies revealed that BDDGE penetrates disposable PVC and rubber gloves in less than 30 min; thus, contaminated gloves should be replaced immediately. Reactive diluents should be included in patch test series if contact allergy to epoxy products is suspected.

Health-hazard-evaluation report MHETA 89-362-2027, Helen Mining Company, Homer City, Pennsylvania

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferguson, R.P.

1990-03-01

In response to a request from the United Mine Workers of America, an investigation was made of possible hazardous working conditions at the Helen Mining Company, Homer City, Pennsylvania. One of the tipple operators had complained of headaches, dizziness and skin rashes from working with a mixture of solvents used in the float/sink test operation. The solvents included perchloroethylene and dibromomethane. A week prior to receiving the request, the use of dibromomethane had been discontinued. Consequently, on the visit to the site, no traces of dibromomethane were found. After engineering controls were installed, only one of seven personal breathing zonemore » samples detected any perchloroethylene, and that sample was 0.12 parts per million, at the limit of detection. The author concludes that a hazard from perchloroethylene did not exist at the time of the evaluation. The author recommends replacing the rubber/cloth type glove being used with either a Teflon or Viton glove, and enclosing the work table.« less

Isolation and Molecular Characterization of 1-Aminocyclopropane-1-carboxylic Acid Synthase Genes in Hevea brasiliensis

PubMed Central

Zhu, Jia-Hong; Xu, Jing; Chang, Wen-Jun; Zhang, Zhi-Li

2015-01-01

Ethylene is an important factor that stimulates Hevea brasiliensis to produce natural rubber. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a rate-limiting enzyme in ethylene biosynthesis. However, knowledge of the ACS gene family of H. brasiliensis is limited. In this study, nine ACS-like genes were identified in H. brasiliensis. Sequence and phylogenetic analysis results confirmed that seven isozymes (HbACS1–7) of these nine ACS-like genes were similar to ACS isozymes with ACS activity in other plants. Expression analysis results showed that seven ACS genes were differentially expressed in roots, barks, flowers, and leaves of H. brasiliensis. However, no or low ACS gene expression was detected in the latex of H. brasiliensis. Moreover, seven genes were differentially up-regulated by ethylene treatment.These results provided relevant information to help determine the functions of the ACS gene in H. brasiliensis, particularly the functions in regulating ethylene stimulation of latex production. PMID:25690030

Molecular cloning of mevalonate pathway genes from Taraxacum brevicorniculatum and functional characterisation of the key enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase.

PubMed

van Deenen, Nicole; Bachmann, Anne-Lena; Schmidt, Thomas; Schaller, Hubert; Sand, Jennifer; Prüfer, Dirk; Schulze Gronover, Christian

2012-04-01

Taraxacum brevicorniculatum is known to produce high quality rubber. The biosynthesis of rubber is dependent on isopentenyl pyrophosphate (IPP) precursors derived from the mevalonate (MVA) pathway. The cDNA sequences of seven MVA pathway genes from latex of T. brevicorniculatum were isolated, including three cDNA sequences encoding for 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductases (TbHMGR1-3). Expression analyses indicate an important role of TbHMGR1 as well as for the HMG-CoA synthase (TbHMGS), the diphosphomevalonate decarboxylase and the mevalonate kinase in the provision of precursors for rubber biosynthesis. The amino acid sequences of the TbHMGRs show the typical motifs described for plant HMGRs such as two transmembrane domains and a catalytic domain containing two HMG-CoA and two NADP(H) binding sites. The functionality of the HMGRs was demonstrated by complementation assay using an IPP auxotroph mutant of Escherichia coli. Furthermore, the transient expression of the catalytic domains of TbHMGR1 and TbHMGR2 in Nicotiana benthamiana resulted in a strong accumulation of sterol precursors, one of the major groups of pathway end-products.

Occupational Risk Factors and Asthma among Health Care Professionals

PubMed Central

Delclos, George L.; Gimeno, David; Arif, Ahmed A.; Burau, Keith D.; Carson, Arch; Lusk, Christine; Stock, Thomas; Symanski, Elaine; Whitehead, Lawrence W.; Zock, Jan-Paul; Benavides, Fernando G.; Antó, Josep M.

2007-01-01

Rationale: Recent U.S. data suggest an increased risk of work-related asthma among health care workers, yet only a few specific determinants have been elucidated. Objectives: To evaluate associations of asthma prevalence with occupational exposures in a cross-sectional survey of health care professionals. Methods: A detailed questionnaire was mailed to a random sample (n = 5,600) of all Texas physicians, nurses, respiratory therapists, and occupational therapists with active licenses in 2003. Information on asthma symptoms and nonoccupational asthma risk factors obtained from the questionnaire was linked to occupational exposures derived through an industry-specific job-exposure matrix. Measurements: There were two a priori defined outcomes: (1) physician-diagnosed asthma with onset after entry into health care (“reported asthma”) and (2) “bronchial hyperresponsiveness–related symptoms,” defined through an 8-item symptom-based predictor. Main Results: Overall response rate was 66%. The final study population consisted of 862 physicians, 941 nurses, 968 occupational therapists, and 879 respiratory therapists (n = 3,650). Reported asthma was associated with medical instrument cleaning (odds ratio [OR], 2.22; 95% confidence interval [CI], 1.34–3.67), general cleaning (OR, 2.02; 95% CI, 1.20–3.40), use of powdered latex gloves between 1992 and 2000 (OR, 2.17; 95% CI, 1.27–3.73), and administration of aerosolized medications (OR, 1.72; 95% CI, 1.05–2.83). The risk associated with latex glove use was not apparent after 2000. Bronchial hyperresponsiveness–related symptoms were associated with general cleaning (OR, 1.63; 95% CI, 1.21–2.19), aerosolized medication administration (OR, 1.40; 95% CI, 1.06–1.84), use of adhesives on patients (OR, 1.65; 95% CI, 1.22–2.24), and exposure to a chemical spill (OR, 2.02; 95% CI, 1.28–3.21). Conclusions: The contribution of occupational exposures to asthma in health care professionals is not trivial, meriting both implementation of appropriate controls and further study. PMID:17185646

Tailoring Dielectric and Actuated Properties of Elastomer Composites by Bioinspired Poly(dopamine) Encapsulated Graphene Oxide.

PubMed

Ning, Nanying; Ma, Qin; Liu, Suting; Tian, Ming; Zhang, Liqun; Nishi, Toshio

2015-05-27

In this study, we obtained dielectric elastomer composites with controllable dielectric and actuated properties by using a biomimetic method. We used dopamine (DA) to simultaneously coat the graphene oxide (GO) and partially reduce GO by self-polymerization of DA on GO. The poly(dopamine) (PDA) coated GO (GO-PDA) was assembled around rubber latex particles by hydrogen bonding interaction between carboxyl groups of carboxylated nitrile rubber (XNBR) and imino groups or phenolic hydroxyl groups of GO-PDA during latex compounding, forming a segregated GO-PDA network at a low percolation threshold. The results showed that the introduction of PDA on GO prevented the restack of GO in the matrix. The dielectric and actuated properties of the composites depend on the thickness of PDA shell. The dielectric loss and the elastic modulus decrease, and the breakdown strength increases with increasing the thickness of PDA shell. The maximum actuated strain increases from 1.7% for GO/XNBR composite to 4.4% for GO-PDA/XNBR composites with the PDA thickness of about 5.4 nm. The actuated strain at a low electric field (2 kV/mm) obviously increases from 0.2% for pure XNBR to 2.3% for GO-PDA/XNBR composite with the PDA thickness of 1.1 nm, much higher than that of other DEs reported in previous studies. Thus, we successfully obtained dielectric composites with low dielectric loss and improved breakdown strength and actuated strain at a low electric field, facilitating the wide application of dielectric elastomers.

Allergic Reactions to Dental Materials-A Systematic Review

PubMed Central

Chopra, Radhika; Sachdev, Vinod

2015-01-01

Introduction Utility of various dental materials ranging from diagnosis to rehabilitation for the management of oral diseases are not devoid of posing a potential risk of inducing allergic reactions to the patient, technician and dentist. This review aims to develop a systematic approach for the selection and monitoring of dental materials available in the market thereby giving an insight to predict their risk of inducing allergic reactions. Materials and Methods Our data included 71 relevant articles which included 60 case reports, 8 prospective studies and 3 retrospective studies. The source of these articles was Pub Med search done with the following terms: allergies to impression materials, sodium hypochlorite, Ledermix paste, zinc oxide eugenol, formaldehyde, Latex gloves, Methyl methacrylate, fissure sealant, composites, mercury, Nickel-chromium, Titanium, polishing paste and local anaesthesia. All the relevant articles and their references were analysed. The clinical manifestations of allergy to different dental materials based on different case reports were reviewed. Results After reviewing the literature, we found that the dental material reported to cause most adverse reactions in patients is amalgam and the incidence of oral lichenoid reactions adjacent to amalgam restorations occur more often than other dental materials. Conclusion The most common allergic reactions in dental staff are allergies to latex, acrylates and formaldehyde. While polymethylmethacrylates and latex trigger delayed hypersensitivity reactions, sodium metabisulphite and nickel cause immediate reactions. Over the last few years, due to the rise in number of patients with allergies from different materials, the practicing dentists should have knowledge about documented allergies to known materials and thus avoid such allergic manifestations in the dental clinic. PMID:26557634

2-[(Hydroxymethyl)amino]ethanol in water as a preservative: Study of formaldehyde released by Taguchi's method

NASA Astrophysics Data System (ADS)

Wisessirikul, W.; Loykulnant, S.; Montha, S.; Fhulua, T.; Prapainainar, P.

2016-06-01

This research studied the quantity of free formaldehyde released from 2- [(hydroxymethyl)amino]ethanol (HAE) in DI water and natural rubber latex mixture using high-performance liquid chromatography (HPLC) technique. The quantity of formaldehyde retained in the solution was cross-checked by using titration technique. The investigated factors were the concentration of preservative (HAE), pH, and temperature. Taguchi's method was used to design the experiments. The number of experiments was reduced to 16 experiments from all possible experiments by orthogonal arrays (3 factors and 4 levels in each factor). Minitab program was used as a tool for statistical calculation and for finding the suitable condition for the preservative system. HPLC studies showed that higher temperature and higher concentration of the preservative influence the amount of formaldehyde released. It was found that conditions at which formaldehyde was released in the lowest amount were 1.6%w/v HAE, 4 to 40 °C, and the original pH. Nevertheless, the pH value of NR latex should be more than 10 (the suitable pH value was found to be 13). This preservative can be used to replace current preservative systems and can maintain the quality of latex for long-term storage. Use of the proposed preservative system was also shown to have reduced impact on the toxicity of the environment.

Modeling of skeletal members using polyurethane foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sena, J.M.F.; Weaver, R.W.

1983-11-01

At the request of the University of New Mexico's Maxwell Museum of Anthropology, members of the Plastic Section in the Process Development Division at SNLA undertook the special project of the Chaco Lady. The project consisted of polyurethane foam casting of a disinterred female skull considered to be approximately 1000 years old. Rubber latex molds, supplied by the UNM Anthropology Department, were used to produce the polymeric skull requested. The authors developed for the project a modified foaming process which will be used in future polyurethane castings of archaeological artifacts and contemporary skeletal members at the University.

Acute urinary retention: which catheter?

PubMed Central

Allardice, J. T.; Standfield, N. J.; Wyatt, A. P.

1988-01-01

There is no scientific data on which is the best method and catheter to use in acute urinary retention in males. We therefore compared the efficiency of a size 12 G latex rubber balloon catheter with a similar calibre but more expensive catheter made of polyvinyl-chloride (PVC). A total of 50 patients was studied and a 100% successful catheterisation rate was recorded at first attempt with both catheters, with no significant complications. The importance of the correct management of acute urinary retention, especially adequate analgesia, is stressed and it is concluded that either catheter is satisfactory. PMID:3207328

Analysis of B-cell epitopes from the allergen Hev b 6.02 revealed by using blocking antibodies.

PubMed

Pedraza-Escalona, Martha; Becerril-Luján, Baltazar; Agundis, Concepción; Domínguez-Ramírez, Lenin; Pereyra, Ali; Riaño-Umbarila, Lidia; Rodríguez-Romero, Adela

2009-02-01

Hev b 6.02 (hevein), identified as a major allergen from natural rubber latex (NRL), is involved in the latex-fruit syndrome and also acts as a pathogenesis defense-related protein. Its 3D structure has been solved at high resolution, and its linear epitopes have already been reported. However, information about conformational epitopes is still controversial, even though it is relevant for an accurate diagnosis and treatment, as well as for the study of allergen-antibody molecular interactions. We sought to analyze the B-cell epitopes of Hev b 6.02 at a molecular and structural level, using specific recombinant antibodies. We obtained a murine monoclonal antibody (mAb 6E7) and three human single chain fragments (scFvs A6, H8, and G7) anti-Hev b 6.02 that were able to compete for hevein binding with serum IgEs from latex allergic patients. In vitro assays showed that the mAb 6E7 and scFv H8 recognized the area of Hev b 6.02 where the aromatic residues are exposed; while the scFv G7 defined the amino and carboxy-terminal regions that lie close to each other, as a different epitope. The structural modeling of the Hev b 6.02-scFv H8 and Hev b 6.02-scFv G7 complexes revealed the putative regions of two conformational epitopes. In one of these, the aromatic residues, as well as polar side chains are important for the interaction, suggesting that they are part of a dominant conformational epitope also presented on the Hev b 6.02-IgE interactions. Antibodies recognizing this important allergen have potential to be used to diagnose and ultimately treat latex allergy.

Rotation Disk Process to Assess the Influence of Metals and Voltage on the Growth of Biofilm

PubMed Central

Barry, Dana M.; McGrath, Paul B.

2016-01-01

Biofilms consist of not only bacteria but also extracellular polymer substrates (EPS). They are groups of microorganisms that adhere to each other on a surface, especially as a result of exposure to water and bacteria. They can pose health risks to humans as they grow in hospital settings that include medical supplies and devices. In a previous study, the researchers discovered that bacteria/biofilm grew well on wetted external latex, male catheters. These results concerned the investigators and encouraged them to find ways for prohibiting the growth of bacteria/biofilm on the male catheters (which are made of natural rubber). They carried out a new study to assess the influence of metals and voltage for the growth of bacteria on these latex samples. For this purpose, a unique Rotation Disk Reactor was used to accelerate biofilm formation on external male catheter samples. This setup included a dip tank containing water and a rotating wheel with the attached latex samples (some of which had single electrodes while others had paired electrodes with applied voltage). The process allowed the samples to become wetted and also exposed them to microorganisms in the ambient air during each revolution of the wheel. The results (as viewed from SEM images) showed that when compared to the control sample, the presence of metals (brass, stainless steel, and silver) was generally effective in preventing bacterial growth. Also the use of voltage (9.5 volt battery) essentially eliminated the appearance of rod shaped bacteria in some of the samples. It can be concluded that the presence of metals significantly reduced bacterial growth on latex and the application of voltage was able to essentially eliminate bacteria, providing appropriate electrode combinations were used. PMID:28773689

Immobilization of the proteins in the natural rubber with dialdehyde sodium alginate.

PubMed

Gong, Ying; Liu, Guangjiao; Peng, Wei; Su, Xiaoyu; Chen, Jiping

2013-11-06

The biodegradable dialdehyde sodium alginate (DASA) was exploited to immobilize the proteins in the natural rubber latex (NRL) and the variations of the properties for the NRL films were estimated in detail. As demonstrated, the proteins were distributed more uniformly in the NRL films with DASA and the extractable protein (EP) content was effectively decreased. Particularly, the EP content was lowered to a value about 46 μg/g with 0.40% DASA, which could meet with the demands of the allergy protein threshold limit of 50 μg/g as described in ASTM D 5712 standard. Furthermore, there was some improve on the burial degradability of the NRL films modified with DASA. The mechanical properties, however, had no evident variation in the presence of DASA. In conclusion, the immobilization of the proteins with DASA should be a potential alternative to tackle the protein allergy problem for the NRL and its products. Copyright © 2013 Elsevier Ltd. All rights reserved.

Neuromorphic Vibrotactile Stimulation of Fingertips for Encoding Object Stiffness in Telepresence Sensory Substitution and Augmentation Applications

PubMed Central

Sorgini, Francesca; Massari, Luca; D’Abbraccio, Jessica; Petrovic, Petar B.; Carrozza, Maria Chiara; Newell, Fiona N.

2018-01-01

We present a tactile telepresence system for real-time transmission of information about object stiffness to the human fingertips. Experimental tests were performed across two laboratories (Italy and Ireland). In the Italian laboratory, a mechatronic sensing platform indented different rubber samples. Information about rubber stiffness was converted into on-off events using a neuronal spiking model and sent to a vibrotactile glove in the Irish laboratory. Participants discriminated the variation of the stiffness of stimuli according to a two-alternative forced choice protocol. Stiffness discrimination was based on the variation of the temporal pattern of spikes generated during the indentation of the rubber samples. The results suggest that vibrotactile stimulation can effectively simulate surface stiffness when using neuronal spiking models to trigger vibrations in the haptic interface. Specifically, fractional variations of stiffness down to 0.67 were significantly discriminated with the developed neuromorphic haptic interface. This is a performance comparable, though slightly worse, to the threshold obtained in a benchmark experiment evaluating the same set of stimuli naturally with the own hand. Our paper presents a bioinspired method for delivering sensory feedback about object properties to human skin based on contingency–mimetic neuronal models, and can be useful for the design of high performance haptic devices. PMID:29342076

Occupational contact sensitization in female geriatric nurses: Data of the Information Network of Departments of Dermatology (IVDK) 2005-2014.

PubMed

Schubert, S; Bauer, A; Molin, S; Skudlik, C; Geier, J

2017-03-01

Geriatric nurses (GN) have a high risk of occupational contact dermatitis (OCD), with chronic irritant contact dermatitis predominating. However, allergic contact dermatitis is an important issue as well. Little is known whether the relevant occupational allergen spectrum reported in the 1990s, including fragrances, preservatives, rubber chemicals and ingredients of surface disinfectants to be the most common sensitizers in GN, is still valid. To monitor the current allergen spectrum in GN with OCD and verify the validity of the patch test recommendations (baseline-, preservative-, ointment base-, rubber-, disinfectant, series and fragrances) in GN with suspected OCD given by the German Contact Dermatitis Research Group (DKG). Retrospective analysis of IVDK data (2005-2014) of 743 female GN with OCD, in comparison to 695 GN without OCD. GN with OCD reacted significantly more frequently to both fragrance mixes, hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC), thiuram mix, zinc diethyldithiocarbamate and mercaptobenzothiazole than GN without OCD. Reactions to MDBGN, methylchloroisothiazolinone/methylisothiazolinone and oil of turpentine occurred substantially, but not significantly more frequently among GN with OCD. The latter may be due to former use of a special alcoholic liniment in geriatric care. Among material from the patients' workplaces, tetrazepam was a frequent allergen, due to dust exposure from pill crushing. Furthermore, occupationally used protective gloves, body care products as well as surface disinfectants were often tested positively. The general allergen spectrum in GN with OCD is unchanged, so the DKG patch test recommendations are still valid. Prevention of occupational sensitization should focus on fragrance-free hygiene and body care products, usage of accelerator-free protective gloves and avoidance of drug dust exposure. © 2016 European Academy of Dermatology and Venereology.

Industrial-hygiene survey report, Wabash Magnetic Company, Huntington, Indiana, May 24-26, 1988. [4,4'-methylenedianiline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boeniger, M.F.

1989-01-01

A walk-through survey was made at Wabash Magnetic Company, located in Huntington, Indiana for the purpose of determining the extent of worker exposure to 4,4'-methylenedianiline (MDA) in a batch type mixing operation and user of B-stage resins. At this site the chemical was used as a hardening agent to produce the resins used to make transfer-molded parts. Air, wipe, bulk, and urine samples were taken to determine exposure levels. In both the formulating and molding departments, evidence was found for the possible inhalation of and dermal contact with MDA. Air concentrations were detectable, but were below the permissible exposure levelmore » of 10 parts per billion (ppb) proposed by OSHA. Of seven workers monitored by urinalysis, two were excreting detectable amounts of MDA with the higher concentration being 16 ppb. The author recommends a combination of modified work practices and alternative personal protection to reduce exposures. A vacuum installed with a HEPA filter should be used in the dry cleanup processes in the mixing and formulating departments and workers should wear a glove more resistant to permeation than the cotton ones now in use at the site. Gloves made of polyvinylchloride or natural latex are suggested.« less

Assembly and Analysis of Differential Transcriptome Responses of Hevea brasiliensis on Interaction with Microcyclus ulei

PubMed Central

Restrepo Restrepo, Silvia; Aristizábal Gutiérrez, Fabio Ancizar; Montoya Castaño, Dolly

2015-01-01

Natural rubber (Hevea brasiliensis) is a tropical tree used commercially for the production of latex, from which 40,000 products are generated. The fungus Microcyclus ulei infects this tree, causing South American leaf blight (SALB) disease. This disease causes developmental delays and significant crop losses, thereby decreasing the production of latex. Currently several groups are working on obtaining clones of rubber tree with durable resistance to SALB through the use of extensive molecular biology techniques. In this study, we used a secondary clone that was resistant to M. ulei isolate GCL012. This clone, FX 3864 was obtained by crossing between clones PB 86 and B 38 (H. brasiliensis x H. brasiliensis). RNA-Seq high-throughput sequencing technology was used to analyze the differential expression of the FX 3864 clone transcriptome at 0 and 48 h post infection (hpi) with the M. ulei isolate GCL012. A total of 158,134,220 reads were assembled using the de novo assembly strategy to generate 90,775 contigs with an N50 of 1672. Using a reference-based assembly, 76,278 contigs were generated with an N50 of 1324. We identified 86 differentially expressed genes associated with the defense response of FX 3864 to GCL012. Seven putative genes members of the AP2/ERF ethylene (ET)-dependent superfamily were found to be down-regulated. An increase in salicylic acid (SA) was associated with the up-regulation of three genes involved in cell wall synthesis and remodeling, as well as in the down-regulation of the putative gene CPR5. The defense response of FX 3864 against the GCL012 isolate was associated with the antagonistic SA, ET and jasmonic acid (JA) pathways. These responses are characteristic of plant resistance to biotrophic pathogens. PMID:26287380

Development of a prototype movement assistance system for extravehicular activity gloves

NASA Astrophysics Data System (ADS)

Hill, Tyler N.

Spacesuits utilized a rubberized layer of material to contain a pressurized atmosphere to facilitate respiration and maintain the physiologic functions of the astronaut residing within. However, the elasticity of the material makes it resistant to deformation increasing the amount of work required during movement. This becomes particularly fatiguing for the muscle groups controlling the motion of the hands and fingers. To mitigate this a robotic system was proposed and developed. The system built upon previous concepts and prototypes discovered through research efforts. It utilized electric motors to pull the index, ring, and middle fingers of the right hand closed, ideally overcoming the resistive force posed by the pressurized elastic material. The effect of the system was determined by comparing qualitative and quantitative data obtained during activities conducted with and without it within a glove box. It was found that the system was able to offload some of this elastic force though several characteristics of the design limited the full potential this device offered. None the less, the project was met with success and provides a solid platform for continued research and development.

Demonstration of spread-on peel-off consumer products for sampling surfaces contaminated with pesticides and chemical warfare agent signatures.

PubMed

Behringer, Deborah L; Smith, Deborah L; Katona, Vanessa R; Lewis, Alan T; Hernon-Kenny, Laura A; Crenshaw, Michael D

2014-08-01

A terrorist attack using toxic chemicals is an international concern. The utility of rubber cement and latex body paint as spray-on/spread-on peel-off collection media for signatures attributable to pesticides and chemical warfare agents from interior building and public transportation surfaces two weeks post-deposition is demonstrated. The efficacy of these media to sample escalator handrail, stainless steel, vinyl upholstery fabric, and wood flooring is demonstrated for two pesticides and eight chemicals related to chemical warfare agents. The chemicals tested are nicotine, parathion, atropine, diisopropyl methylphosphonate, dimethyl methylphosphonate, dipinacolyl methylphosphonate, ethyl methylphosphonic acid, isopropyl methylphosphonic acid, methylphosphonic acid, and thiodiglycol. Amounts of each chemical found are generally greatest when latex body paint is used. Analytes with low volatility and containing an alkaline nitrogen or a sulfur atom (e.g., nicotine and parathion) usually are recovered to a greater extent than the neutral phosphonate diesters and acidic phosphonic acids (e.g., dimethyl methylphosphonate and ethyl methylphosphonic acid). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Experimental investigation on the morphology of soot aggregates from the burning of typical solid and liquid fuels

NASA Astrophysics Data System (ADS)

Huang, Dongmei; Guo, Chenning; Shi, Long

2017-03-01

Soot particles from the burning of typical fuels are one of the critical sources causing environmental problems and human disease. To understand the soot formation of these typical fuels, the size and morphology of soot aggregates produced from the burning of typical solid and liquid fuels, including diesel, kerosene, natural rubber (NR) latex foam, and wood crib, were studied by both extractive sampling and subsequent image analysis. The 2D and 3D fractal dimensions together with the diameter distribution of agglomerate and primary particles were analyzed for these four typical fuels. The average diameters of the primary particles were within 45-85 nm when sampling from different heights above the fire sources. Irregular sheet structures and flake-like masses were observed from the burning of NR latex foam and wood cribs. Superaggregates with a mean maximum length scale of over 100 μm were also found from the burning of all these four tested fuels. The fractal dimension of a single aggregate was 3 for all the tested fuels.

Occupational exposure to cytotoxic drugs in two UK oncology wards

PubMed Central

Ziegler, E; Mason, H; Baxter, P

2002-01-01

Aims: To investigate the potential exposure to cytotoxic drugs of staff on two oncology wards in a large district, UK hospital under normal working conditions. Methods: Cytotoxic drug exposure was monitored in urine samples, surface wipes, and on disposable gloves by using a number of commonly used marker drugs, namely cyclophosphamide, ifosfamide, methotrexate, and the platino coordinated drugs. Questionnaire data on their work practices, potential exposure, use of protective personal equipment, and relevant training were collected from nursing, domestic, and clerical staff on two oncology wards. Results: The majority of staff were female with a mean age of 31 years. Roughly half of the staff studied were specifically trained nurses with an average of 3.5 years experience of administering cytotoxic drugs. No cytotoxic drug preparation or reconstitution was carried out on the wards. Disposable gloves, plastic armlets and aprons, but not eye protection, were invariably worn where there was potential exposure to cytotoxics. No cytotoxic drug was detected in any of the staff's urine samples. Isolated disposable latex gloves from nurses administering drugs showed some contamination, as did some surfaces within the wards' sluice rooms, but not in the ward areas where the drugs were stored and checked prior to administration. Conclusions: The risk management strategies in place, including use of personal protective equipment, staff training, and other organisational measures, have ensured that internal exposure is lower than the detection limits for the current biological monitoring methods. Levels of contamination appear significantly lower than earlier, non-UK published studies where different risk management strategies were in place and, in particular, ward staff may have been involved in some degree of cytotoxic drug reconstitution. PMID:12205233

Effects of educational intervention on adherence to the technical recommendations for tracheobronchial aspiration in patients admitted to an intensive care unit

PubMed Central

de Lima, Erimara Dall'Agnol; Fleck, Caren Schlottefeld; Borges, Januário José Vieira; Condessa, Robledo Leal; Vieira, Sílvia Regina Rios

2013-01-01

Objective To evaluate the effectiveness of an educational intervention on healthcare professionals' adherence to the technical recommendations for tracheobronchial aspiration in intensive care unit patients. Methods A quasi-experimental study was performed to evaluate intensive care unit professionals' adherence to the tracheobronchial aspiration technical recommendations in intensive care unit patients both before and after a theoretical and practical educational intervention. Comparisons were performed using the chi-square test, and the significance level was set to p<0.05. Results A total of 124 procedures, pre- and post-intervention, were observed. Increased adherence was observed in the following actions: the use of personal protective equipment (p=0.01); precaution when opening the catheter package (p<0.001); the use of a sterile glove on the dominant hand to remove the catheter (p=0.003); the contact of the sterile glove with the catheter only (p<0.001); the execution of circular movements during the catheter removal (p<0.001); wrapping the catheter in the sterile glove at the end of the procedure (p=0.003); the use of distilled water, opened at the start of the procedure, to wash the connection latex (p=0.002); the disposal of the leftover distilled water at the end of the procedure (p<0.001); and the performance of the aspiration technique procedures (p<0.001). Conclusion There was a low adherence by health professionals to the preventive measures against hospital infection, indicating the need to implement educational strategies. The educational intervention used was shown to be effective in increasing adherence to the technical recommendations for tracheobronchial aspiration. PMID:23917976

[Primary cutaneous aspergillosis complicated with invasive aspergillosis in an extremely preterm infant: case report and literature review].

PubMed

Stock, C; Veyrier, M; Magnin-Verschelde, S; Duband, S; Lavocat, M-P; Teyssier, G; Berthelot, P

2010-10-01

Aspergillus is a ubiquitous fungus that can cause primary cutaneous aspergillosis in extremely low-birth-weight (ELBW) neonates, then be invasive and lead to death. ELBW neonates are particularly at risk because of decreased qualitative immune defenses and defects in the skin barrier. Broad-spectrum antimicrobial therapy and corticosteroids, often used in these patients, contribute to increased risk. We present a fatal case of primary cutaneous aspergillosis complicated with invasive aspergillosis, confirmed by autopsy, in an ELBW infant. The source of contamination was probably non-sterile disposable latex gloves used for neonatal care. The early recognition of this source led to its eviction for other hospitalized ELBW infants and no outbreak was observed. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

The prevalence and diagnostic value of specific IgE antibodies to inhalant, animal and plant food, and ficus allergens in patients with natural rubber latex allergy.

PubMed

Ebo, D G; Bridts, C H; Hagendorens, M M; De Clerck, L S; Stevens, W J

2003-01-01

It is well recognised that natural rubber latex allergy can be associated with serological cross-reactivity to plant allergens, especially tropical fruits and Ficus. In contrast, data on the frequency and clinical value of specific IgE antibodies against these allergens remain rare. In addition, little is known about the prevalence and diagnostic value of specific IgE antibodies to classical inhalant and animal allergens in NRL allergic patients. The purpose of this study was to investigate the prevalence, the sensitivity, and the specificity of these different specific IgE antibodies in patients suffering from NRL allergy. Serum samples of 42 NRL allergic adults were investigated. All had a history of NRL allergy confirmed by a positive skin test for latex and a positive latex-specific IgE. Samples were analysed for IgE antibodies against 9 plant food allergens (avocado, banana, chestnut, fig, kiwi, papaya, peanut, pineapple and tomato) and Ficus benjamina. A specific IgE quantification for 3 animal food allergens (codfish, cow's milk, egg's white) and 8 common inhalant allergens (Dermatophagoïdes pteronyssinus, birch pollen, timothy grass pollen, mugwort pollen, cat and dog epithelium, Aspergillus fumigatus and Cladosporium herbarum) was also performed. Because double blind placebo-controlled challenges could not be considered, for ethical reasons, patient's food allergy or immediate hypersensitivity for Ficus and inhalant allergens was documented by a standardised questionnaire. Diagnosis of atopy was based on a relevant history and the presence of a specific IgE antibody to at least one classical inhalant allergen. For some IgE determinations presence or absence of cross-reactivity was investigated by CAP-inhibition tests. A specific IgE antibody to at least one of the investigated inhalant and animal food allergens was found in respectively 76% and 12% of the serum samples. A plant food-specific IgE antibody was observed in 88% of the serum samples, most frequently to papaya (71%) and least frequently to kiwi (17%). Twenty-nine percent of the serum samples contained Ficus-IgE. According to the questionnaire and the threshold of 0.35 kUa/L, sensitivity of the plant food IgE antibodies varied between 0% for papaya and 73% for avocado. Specificity varied between 28% for papaya and 91% for kiwi. For Ficus-IgE sensitivity was 20% and specificity 70%. For inhalant and animal food allergens sensitivity and specificity of the IgE quantification correlated generally well with the values obtained in non-NRL allergic adults. Determination of specific IgE to the investigated plant foods and Ficus was not always a sensitive neither a specific test to establish the clinical diagnosis of this allergy.

Transpiration characteristics of a rubber plantation in central Cambodia.

PubMed

Kobayashi, Nakako; Kumagai, Tomo'omi; Miyazawa, Yoshiyuki; Matsumoto, Kazuho; Tateishi, Makiko; Lim, Tiva K; Mudd, Ryan G; Ziegler, Alan D; Giambelluca, Thomas W; Yin, Song

2014-03-01

The rapid and widespread expansion of rubber plantations in Southeast Asia necessitates a greater understanding of tree physiology and the impacts of water consumption on local hydrology. Sap flow measurements were used to study the intra- and inter-annual variations in transpiration rate (Et) in a rubber stand in the low-elevation plain of central Cambodia. Mean stand sap flux density (JS) indicates that rubber trees actively transpire in the rainy season, but become inactive in the dry season. A sharp, brief drop in JS occurred simultaneously with leaf shedding in the middle of the dry season in January. Although the annual maxima of JS were approximately the same in the two study years, the maximum daily stand Et of ∼2.0 mm day(-1) in 2010 increased to ∼2.4 mm day(-1) in 2011. Canopy-level stomatal response was well explained by changes in solar radiation, vapor pressure deficit, soil moisture availability, leaf area, and stem diameter. Rubber trees had a relatively small potential to transpire at the beginning of the study period, compared with average diffuse-porous species. After 2 years of growth in stem diameter, transpiration potential was comparable to other species. The sensitivity of canopy conductance (gc) to atmospheric drought indicates isohydric behavior of rubber trees. Modeling also predicted a relatively small sensitivity of gc to the soil moisture deficit and a rapid decrease in gc under extreme drought conditions. However, annual observations suggest the possibility of a change in leaf characteristics with tree maturity and/or initiation of latex tapping. The estimated annual stand Et was 469 mm year(-1) in 2010, increasing to 658 mm year(-1) in 2011. Diagnostic analysis using the derived gc model showed that inter-annual change in stand Et in the rapidly growing young rubber stand was determined mainly by tree growth rate, not by differences in air and soil variables in the surrounding environment. Future research should focus on the potentially broad applicability of the relationship between Et and tree size as well as environmental factors at stands different in terms of clonal type and age.

STS-46 ESA MS Nicollier conducts IFM on OV-104's waste collection system

NASA Technical Reports Server (NTRS)

1992-01-01

STS-46 European Space Agency (ESA) Mission Specialist (MS) Claude Nicollier, wearing goggles, face mask, and rubber gloves, reviews inflight maintenance (IFM) checklist procedures before starting waste collection system (WCS) fan separator repair. One of two fan separators used to transfer waster water from the waste management compartment (WMC) to the waste water tank has failed. The suspected accumulation of water in the separator was believed to have occurred during a test dumping of waste water at a lower than normal pressure to evaluate the performance of new nozzles. The WMC is located on the middeck of Atlantis, Orbiter Vehicle (OV) 104.

Preparation and properties of carboxylated styrene-butadiene rubber/cellulose nanocrystals composites.

PubMed

Cao, Xiaodong; Xu, Chuanhui; Liu, Yuhong; Chen, Yukun

2013-01-30

A series of carboxylated styrene-butadiene rubber (XSBR)/cellulose nanocrystals (CNs) latex composites were successfully prepared. The vulcanization process, morphology, dynamic viscoelastic behavior, dynamic mechanical property, thermal and mechanical performance of the XSBR/CNs composites were investigated in detail. The results revealed that CNs were dispersed uniformly in the XSBR matrix and formed a strong filler-filler network. The dynamic mechanical analysis (DMA) showed that the glass transition temperature (T(g)) of XSBR matrix was shifted from 48.45 to 50.64 °C with 3 phr CNs, but decreased from 50.64 to 46.28 °C when further increasing CNs content up to 15 phr. The composites exhibited a significant enhancement in tensile strength (from 16.9 to 24.1 MPa) and tear strength (from 43.5 to 65.2 MPa) with loading CNs from 0 to 15 phr. In addition, the thermo-gravimetric analysis (TGA) showed that the temperature at 5% weight loss of the XSBR/CNs composites decreased slightly with an increase of the CNs content. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Comparative analysis of the complete sequence of the plastid genome of Parthenium argentatum and identification of DNA barcodes to differentiate Parthenium species and lines

PubMed Central

2009-01-01

Background Parthenium argentatum (guayule) is an industrial crop that produces latex, which was recently commercialized as a source of latex rubber safe for people with Type I latex allergy. The complete plastid genome of P. argentatum was sequenced. The sequence provides important information useful for genetic engineering strategies. Comparison to the sequences of plastid genomes from three other members of the Asteraceae, Lactuca sativa, Guitozia abyssinica and Helianthus annuus revealed details of the evolution of the four genomes. Chloroplast-specific DNA barcodes were developed for identification of Parthenium species and lines. Results The complete plastid genome of P. argentatum is 152,803 bp. Based on the overall comparison of individual protein coding genes with those in L. sativa, G. abyssinica and H. annuus, we demonstrate that the P. argentatum chloroplast genome sequence is most closely related to that of H. annuus. Similar to chloroplast genomes in G. abyssinica, L. sativa and H. annuus, the plastid genome of P. argentatum has a large 23 kb inversion with a smaller 3.4 kb inversion, within the large inversion. Using the matK and psbA-trnH spacer chloroplast DNA barcodes, three of the four Parthenium species tested, P. tomentosum, P. hysterophorus and P. schottii, can be differentiated from P. argentatum. In addition, we identified lines within P. argentatum. Conclusion The genome sequence of the P. argentatum chloroplast will enrich the sequence resources of plastid genomes in commercial crops. The availability of the complete plastid genome sequence may facilitate transformation efficiency by using the precise sequence of endogenous flanking sequences and regulatory elements in chloroplast transformation vectors. The DNA barcoding study forms the foundation for genetic identification of commercially significant lines of P. argentatum that are important for producing latex. PMID:19917140

IgE reactivity to profilin in pollen-sensitized subjects with adverse reactions to banana and pineapple.

PubMed

Reindl, J; Rihs, H P; Scheurer, S; Wangorsch, A; Haustein, D; Vieths, S

2002-06-01

The so-called 'latex-fruit syndrome' is a well-documented phenomenon in cross-reactive allergies. By contrast, there is a lack of information about allergy to exotic fruits in patients with a predominant pollen sensitization. Since the ubiquitous protein profilin has been identified as an allergen in natural rubber latex as well as in pollen-related foods, the aim of this study was to investigate the role of profilin in allergy to certain exotic fruits. Recombinant profilins from banana and pineapple were cloned by a PCR technique after isolation of total RNA using degenerated profilin-specific primers. The unknown 5' ends of copy DNA (cDNA) were identified by rapid amplification of 5'cDNA ends (5'-RACE) and expression in Escherichia coli BL21(DE3) cells. The recombinant profilins were purified by affinity chromatography using poly-(L)-proline as the solid phase. IgE-binding capabilities were characterized by means of immunoblot and Enzyme Allergosorbent Test (EAST). The cross-reactivity to birch pollen profilin and latex profilin was studied by EAST as well as by immunoblot inhibition experiments. Both banana and pineapple profilin were found to consist of 131 amino acid residues with high amino acid sequence identity to known allergenic pollen and food profilins (71-84%). IgE binding to the recombinant profilins was observed in 7/16 sera from subjects with suspected banana allergy (44%) and in 8/19 sera from subjects with suspected pineapple allergy (42%). Inhibition experiments indicated similar IgE reactivity of natural and recombinant allergens. In addition, high cross-reactivity to birch pollen profilin Bet v 2 and latex profilin Hev b 8 was demonstrated by immunoblot inhibition as well as EAST inhibition experiments. Since a high IgE-binding prevalence of about 40% was obtained in both banana and pineapple allergy, we conclude that profilin is an important mediator of IgE cross-reactivity between pollen and exotic fruits. Copyright 2002 S. Karger AG, Basel

The Effect of Single, Binary and Ternary Anions of Chloride, Carbonate and Phosphate on the Release of 2,4-Dichlorophenoxyacetate Intercalated into the Zn-Al-layered Double Hydroxide Nanohybrid

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir; Jaafar, Adila Mohamad; Yahaya, Asmah Hj.; Zainal, Zulkarnain

2009-11-01

Intercalation of beneficial anion into inorganic host has lead to an opportunity to synthesize various combinations of new organic-inorganic nanohybrids with various potential applications; especially, for the controlled release formulation and storage purposes. Investigation on the release behavior of 2,4-dichlorophenoxyacetate (2,4-D) intercalated into the interlayer of Zn-Al-layered double hydroxide (ZAN) have been carried out using single, binary and ternary aqueous systems of chloride, carbonate and phosphate. The release behavior of the active agent 2,4-D from its double-layered hydroxide nanohybrid ZANDI was found to be of controlled manner governed by pseudo-second order kinetics. It was found that carbonate medium yielded the highest accumulated release of 2,4-D, while phosphate in combination with carbonate and/or nitrate speeds up the release rate of 2,4-D. These results indicate that it is possible to design and develop new delivery system of latex stimulant compound with controlled release property based on 2,4-D that is known as a substance to increase latex production of rubber tree, Hevea brasiliensis.

Electron linear accelerator system for natural rubber vulcanization

NASA Astrophysics Data System (ADS)

Rimjaem, S.; Kongmon, E.; Rhodes, M. W.; Saisut, J.; Thongbai, C.

2017-09-01

Development of an electron accelerator system, beam diagnostic instruments, an irradiation apparatus and electron beam processing methodology for natural rubber vulcanization is underway at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project is carried out with the aims to improve the qualities of natural rubber products. The system consists of a DC thermionic electron gun, 5-cell standing-wave radio-frequency (RF) linear accelerator (linac) with side-coupling cavities and an electron beam irradiation apparatus. This system is used to produce electron beams with an adjustable energy between 0.5 and 4 MeV and a pulse current of 10-100 mA at a pulse repetition rate of 20-400 Hz. An average absorbed dose between 160 and 640 Gy is expected to be archived for 4 MeV electron beam when the accelerator is operated at 400 Hz. The research activities focus firstly on assembling of the accelerator system, study on accelerator properties and electron beam dynamic simulations. The resonant frequency of the RF linac in π/2 operating mode is 2996.82 MHz for the operating temperature of 35 °C. The beam dynamic simulations were conducted by using the code ASTRA. Simulation results suggest that electron beams with an average energy of 4.002 MeV can be obtained when the linac accelerating gradient is 41.7 MV/m. The rms transverse beam size and normalized rms transverse emittance at the linac exit are 0.91 mm and 10.48 π mm·mrad, respectively. This information can then be used as the input data for Monte Carlo simulations to estimate the electron beam penetration depth and dose distribution in the natural rubber latex. The study results from this research will be used to define optimal conditions for natural rubber vulcanization with different electron beam energies and doses. This is very useful for development of future practical industrial accelerator units.

Cerebrospinal fluid eosinophilia and sterile shunt malfunction.

PubMed

Traynelis, V C; Powell, R G; Koss, W; Schochet, S S; Kaufman, H H

1988-11-01

Cerebrospinal fluid (CSF) eosinophilia is a rare finding most often associated with central nervous system inflammatory processes, including parasitic, bacterial, and mycotic infections. It has also been seen as an allergic phenomenon. We present two cases of CSF eosinophilia occurring concurrently with sterile shunt malfunction. We speculate that CSF eosinophilia in our patients might have resulted from an allergic response to a foreign material such as suture, surgical glove powder, hair, cotton fibers, antibiotics, or silicone rubber. The incidence of sterile CSF eosinophilia after shunting is not known. Information concerning the role of eosinophilia in the development of shunt malfunctions is also lacking. An increased awareness of this possibility and further investigation are warranted.