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1.
Planta ; 255(2): 33, 2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-34997357

RESUMO

MAIN CONCLUSION: A putative powdery mildew effector can elicit defense responses including reactive oxygen species and callose accumulations in model plants Nicotiana benthamiana and Arabidopsis thaliana and host plant Hevea brasiliensis. Powdery mildew fungi cause severe diseases in many agricultural plants, such as the mildew fungus Erysiphe quercicola infecting the rubber tree (Hevea brasiliensis), causing latex yield losses. However, effectors of E. quercicola were rarely functionally characterized. In this study, we identified a highly specific candidate-secreted effector protein, EqCSEP04187, from E. quercicola. This putative effector is expressed at the late stage but not the early stage during infection. The constitutive expression of EqCSEP04187 in model plants Nicotiana benthamiana and Arabidopsis thaliana elicited defense responses, as did transient expression of EqCSEP04187 in protoplasts of H. brasiliensis. Introducing EqCSEP04187 into another H. brasiliensis-associated fungal pathogen, Colletotrichum gloeosporioides, inhibited H. brasiliensis infection, and infection by E. quercicola was decreased in the A. thaliana eds1 mutant expressing EqCSEP04187. Further analysis suggests that these reductions in infection were the consequences of EqCSEP04187 eliciting defense responses. Our study suggests that this putative effector has elicitor activity that can improve plant resistance.


Assuntos
Ascomicetos , Hevea , Doenças das Plantas , Imunidade Vegetal , Borracha , Árvores
2.
Rev Alerg Mex ; 69 Suppl 1: s55-s68, 2022.
Artigo em Espanhol | MEDLINE | ID: mdl-34998311

RESUMO

Latex allergy is a major problem worldwide due to both the severity of the symptomatology it produces and the risk groups that are exposed to it. Complete avoidance is difficult, if not impossible, due to its ubiquity. Natural rubber latex (NRL) is a natural polymer that is released by the Hevea brasiliensis (Hev b) tree, which functions as a protective sealant. It is currently used for the manufacture of health-care products such as tube caps, pistons, masks, and cannulas. The purpose of this review is to highlight the epidemiological, clinical, and diagnostic aspects of NRL allergy, and to conduct a review of the literature on its management through a bibliographic search of articles in databases such as PubMed, Cochrane, UpToDate, and Google Scholar, up to September 2021. About 121 articles were reviewed, of which 76 were used as a reference. We concluded that latex allergy is an entity for which its treatment, even nowadays, is avoidance, despite having a worldwide prevalence of 4.3 % and representing a surgical complication in about 20 % of surgeries with an anaphylactic reaction and a mortality rate that can reach 9 %. The only treatment that could modify the evolution of this disease is immunotherapy, but there are no standardized extracts yet and it has not been possible to determine the safest and most effective way to apply it.


Assuntos
Hevea , Hipersensibilidade ao Látex , Alérgenos , Humanos , Hipersensibilidade ao Látex/diagnóstico , Hipersensibilidade ao Látex/epidemiologia , Hipersensibilidade ao Látex/terapia , Prevalência , Borracha
3.
Bioresour Technol ; 344(Pt B): 126306, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34780903

RESUMO

The distribution of biomass pyrolysis products under high pressure have rarely been reported. In this study, the effect of pressure on the product distribution of pine sawdust (PS) pyrolysis was studied. The synergistic effect of the side wall rubber (SWR) and PS was confirmed under pressurized conditions. Calcined bottom ash (CBA) and SWR char (SWRC) were used to enhance the quality of the pressurized co-pyrolysis products. The PS and SWR pyrolysis chars obtained under high pressure conditions exhibited serious melting and cross-linking problem. The CO2 content decreased to 19.96 vol% in co-pyrolysis gas with the CBA/SWRC7/3 catalyst. The water content decreased by 85.71% after the SWRC catalyst in the pressurized co-pyrolysis process. Compared with the concentration of benzene in PS and SWR oil, the concentration of benzene in SWR/PS7/3 oil without catalysts increased by 9.57 times and 0.25 times, respectively.


Assuntos
Pirólise , Madeira , Biomassa , Cinza de Carvão , Borracha
4.
Dentomaxillofac Radiol ; 51(1): 20200323, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34133225

RESUMO

OBJECTIVE: The aim of this study was to construct an anthropomorphic maxillofacial phantom for dental imaging and dosimetry purposes using three-dimensional (3D) printing technology and materials that simulate the radiographic properties of tissues. METHODS: Stereolithography photoreactive resins, polyurethane rubber and epoxy resin were modified by adding calcium carbonate and strontium carbonate powders or glass bubbles. These additives were used to change the materials' CT numbers to mimic various body tissues. A maxillofacial phantom was designed using CT images of a head. RESULTS: Commercial 3D printing resins were found to have CT numbers near 120 HU and were used to print intervertebral discs and an external skin for the maxillofacial phantom. By adding various amounts of calcium carbonate and strontium carbonate powders the CT number of the resin was raised to 1000 & 1500 HU and used to print bone mimics. Epoxy resin modified by adding glass bubbles was used in assembly and as a cartilaginous mimic. Glass bubbles were added to polyurethane rubber to reduce the CT number to simulate soft tissue and filled spaces between the printed anatomy and external skin of the phantom. CONCLUSION: The maxillofacial phantom designed for dental imaging and dosimetry constructed using 3D printing, polyurethane rubbers and epoxy resins represented a patient anatomically and radiographically. The results of the designed phantom, materials and assembly process can be applied to generate different phantoms that better represent diverse patient types and accommodate different ion chambers.


Assuntos
Resinas Epóxi , Borracha , Humanos , Imagens de Fantasmas , Poliuretanos , Impressão Tridimensional , Tomografia Computadorizada por Raios X
5.
Environ Pollut ; 292(Pt A): 118338, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34637836

RESUMO

Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represent a fundamental tool to evaluate possible removal actions. We analysed a 7 years (2013-2019) standardized data series collected along Sardinian fishing grounds through MEDiterranean International Trawl Survey, for which estimates of density and weight of seafloor macro-litter were calculated for over 707 hauls. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. Our data showed how different sources and physical features of macro-litter items (i.e., plastic and fishing gear, rubber, glass, metals, and cloth) led to spatially segregated accumulation hotspots. We also point out here how the identification of seafloor macro-litter hotspots using aggregated data that include plastic items could obscure the identification of other segregated but yet relevant hotspots of other macro-litter categories accumulated in the marine environment. These hotspots often occurred at shallower depths and closer to coastlines, thus representing potential spots where eventual future litter removal action could be prioritized.


Assuntos
Monitoramento Ambiental , Plásticos , Vidro , Mar Mediterrâneo , Metais , Borracha , Resíduos/análise
6.
Bioresour Technol ; 343: 126135, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34655775

RESUMO

The adsorptive removal of Cr(VI) and methylene blue (MB) was studied in a batch reactor using activated carbon (RAC), prepared from natural rubber waste, along with the commercial activated carbon (CAC). Maximum uptake of Cr(VI) and MB by the RAC was 21 and 30 mg g-1, respectively, whereas the corresponding uptake by CAC was 145 and 224 mg g-1. The kinetics of adsorption, however, was found to be faster in RAC than CAC. Both adsorbents were characterized by XRD, FT-IR, and FESEM-EDS. The predictability of various kinetic models, including the Weber-Morris model, was adversely affected by linearization. A multi-linear plot of adsorbed concentration versus square root of time failed to justify the multi-resistance hypothesis of mass transfer. Experimental kinetic data matched well with four surface reactions and an intraparticle diffusion model but showed substantial deviation from the numerical solution of another Fickian model incorporating mass balance and Langmuir isotherm.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno , Borracha , Esgotos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
7.
Waste Manag ; 135: 381-388, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34607263

RESUMO

Due to the complex network of aromatic units, lignin is difficult to achieve high-value applications in the industrial field, becoming the largest "natural waste". In this paper, dual-phase fillers with excellent rubber reinforcement were prepared from lignin and sodium silicate through the method of controllable two-step acid precipitation without any complicated modification. During the formation of hybrid nanoparticles, silica nanoparticles were formed as templates in the first step, and then lignin was used as coating agent to bind with silica. The size and morphology of products could be easily adjusted by changing acid precipitation conditions. The L60SS hybrid nanoparticles with the best reinforcement performance showed the ability to replace carbon black (CB) in a high proportion. In addition, LSRH-S hybrid nanoparticles made from rice husk black liquor had similar physical and chemical properties and excellent reinforcement properties to L60SS. Even if the ratio of each component of the raw material was different, the product could be flexibly controlled by the two-step acid precipitation to obtain the expected properties. The wide applicability of this method in many extraction processes based on alkaline procedures was proved, and it provided a basis for the process design of comprehensive utilization of biomass. This work will promote the application of lignin in high-value fields, and the sustainable development of the rubber industry by utilizing agricultural waste was achieved.


Assuntos
Lignina , Nanopartículas , Biomassa , Borracha , Dióxido de Silício
8.
Int J Mol Sci ; 22(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34639234

RESUMO

This research focuses on revealing the double role of quercetin accompanied by silica in epoxidized natural rubber. A crosslinking ability with antioxidative properties exists and reveals the dependence of these functions on quercetin content. Here, the aging resistance of self-healable biocomposites was analyzed. The self-healing properties were presented in our previous work. The stabilizing effect of quercetin applied as a crosslinking agent has been studied in epoxidized natural rubber with a 50 mol% of epoxidation (ENR-50). Some of five -OH moiety groups existing in the quercetin structure are able to react with epoxy rings of ENR-50 and cure this elastomer, whereas other free hydroxyl groups can donate the hydrogen molecule to a radical molecule, stabilizing it. The aging resistance of prepared composites was estimated by mechanical tests conducted before and after different types of aging, as well as by differences in color and surface energy between aged and un-aged samples. Changes within the oxygen function, which occurred as a result of the aging process, were observed using FT-IR absorbance spectroscopy. Furthermore, the impact of quercetin content on composites' thermal stability was investigated by thermogravimetry (TGA). According to the results, a proper dose of quercetin can act as a crosslinker and antioxidant in ENR-50 at the same time.


Assuntos
Materiais Biocompatíveis/química , Reagentes para Ligações Cruzadas/química , Compostos de Epóxi/química , Quercetina/química , Borracha/química , Dióxido de Silício/química , Fenômenos Mecânicos , Reologia , Temperatura , Resistência à Tração
9.
Huan Jing Ke Xue ; 42(11): 5193-5200, 2021 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-34708958

RESUMO

The emission characteristics of VOCs from three typical rubber manufacture industries were studied by GC-MS/FID. Maximum incremental reactivity(MIR) and fractional aerosol coefficient(FAC) were employed to evaluate the ozone formation potential(OFP) and secondary organic aerosol(SOA) formation potential. The results show that the VOC types emitted from the manufacturing of rubber products mainly include alkanes, ketones, aldehydes, alcohols, and benzene series. For traditional rubber products manufactured through rubber mixing and vulcanization, the main pollutants are ketones and alcohols, whereas for production processes involving gluing and painting, the main pollutants belong to the benzene series. In terms of ozone impact, the traditional processes contribute to ozone formation mainly through oxygenated hydrocarbons. In industries that utilize adhesives and paints, the extensive use of these organic solvents lead to a significantly higher contribution of the benzene series than other VOC species to ozone formation; the benzene series account for 82.9% of the total contribution. In terms of SOA impact, the benzene series are the main contributor to SOA, whereas the contribution of VOCs from traditional processes is small; hence, SOA primarily originates from the gluing and painting processes. Therefore, in traditional production of rubber products through rubber mixing and vulcanization, the emission of oxygenated hydrocarbons should be preferentially controlled, whereas for rubber industries utilizing gluing and painting processes, the emission of benzene series should be preferentially controlled.


Assuntos
Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Ozônio/análise , Borracha , Compostos Orgânicos Voláteis/análise
10.
Sensors (Basel) ; 21(20)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34696045

RESUMO

Sensors are essential in the haptic technology of soft robotics, which includes the technology of humanoids. Haptic sensors can be simulated by the mimetic organ of perceptual cells in the human body. However, there has been little research on the morphological fabrication of cutaneous receptors embedded in a human skin tissue utilizing artificial materials. In the present study, we fabricated artificial, cell-like cutaneous receptors embedded in skin tissue mimicking human skin structure by utilizing rubber. We addressed the fabrication of five cutaneous receptors (free nerve endings, Krause and bulbs, Meissner corpuscles, Pacinian corpuscles and Ruffini endings). In addition, we investigated the effectiveness of the fabricated tissue for mechanical and thermal sensing. At first, in the production of integrated artificial skin tissue, we proposed a novel magnetic, responsive, intelligent, hybrid fluid (HF), which is suitable for developing the hybrid rubber skin. Secondly, we presented the fabrication by utilizing not only the HF rubber but our previously proposed rubber vulcanization and adhesion techniques with electrolytic polymerization. Thirdly, we conducted a mechanical and thermal sensing touch experiment with the finger. As a result, it demonstrated that intelligence as a mechanoreceptor or thermoreceptor depends on its fabric: the HF rubber sensor mimicked Krause and bulbs has the thermal and pressing sensibility, and the one mimicked Ruffini endings the shearing sensibility.


Assuntos
Borracha , Pele Artificial , Humanos , Mecanorreceptores , Pele , Tato
11.
J Dairy Sci ; 104(12): 12881-12886, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34538489

RESUMO

Many male dairy calves are castrated when reared for beef production, but for dairy breeds the assessment of the longer-lasting pain associated with this procedure has received little scientific attention. In this study we assessed 2 methods: surgical (n = 10 calves) and rubber ring (n = 11). All calves were castrated at 28 d of age using multimodal pain control. During the 8 wk that followed, we recorded wound healing, local inflammation, body weight, milk and calf starter intake, lying time, and wound-directed behavior. Surgical wounds were fully healed on average 4 wk after the procedure, but only 1 calf in the rubber ring treatment fully healed within the 8-wk study. Inflammation was greater after rubber ring castration; skin temperature in the area around the lesion was 1.7 ± 0.35°C (mean ± standard deviation) higher than for the surgical treatment. Compared with surgically castrated calves, those castrated by rubber ring gained less weight over the study period (on average 11.9 ± 5.1 kg less), a difference due in part to lower intake of calf starter (on average 1.8 ± 0.6 kg less). Calves in the rubber ring treatment spent less time lying down (on average 4.2 ± 1.2% fewer scans per day) and licked their lesions more frequently (on average 16.0 ± 3.3 more licks per day). We conclude that the rubber ring calves experienced more pain in the weeks following the procedure and thus recommend that surgical castration be favored for preweaning dairy calves.


Assuntos
Orquiectomia , Borracha , Ração Animal/análise , Animais , Comportamento Animal , Peso Corporal , Bovinos , Dieta , Masculino , Orquiectomia/veterinária , Dor/veterinária , Medição da Dor , Desmame
12.
Trop Anim Health Prod ; 53(5): 447, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34532774

RESUMO

The floor surface of the cubicle is a detrimental factor on cow comfort. The effects of two floor types, rubber and concrete, on dairy cow comfort and milk production were compared for a period of 13 weeks. Fourteen Friesian crossbred dairy cows with an average body weight of 425.67 ± 61.12 kg (mean ± SD), nose to tail body length of 2.07 ± 0.15 m, rump height of 1.29 ± 0.02 m, hook bone width of 0.48 ± 0.05 m, and body condition score (BCS) of 4.13 ± 0.44 were used, with seven cows per flooring treatment. The cows produced a mean of 15.93 ± 4.03 l/cow/day and a constant feeding plan was practiced. The swelling and wound severity of hocks diminished (P < 0.05) starting at the third and tenth weeks, respectively. Daily lying time/h (concrete: 9.67 ± 1.24, rubber: 10.60 ± 0.69, P = 0.046) and average duration of lying bouts/min increased (concrete: 58.16 ± 7.74, rubber: 65.66 ± 9.85, P = 0.050) starting from the twelfth week on rubber bedding. Prevalence of mastitis, lameness, and cow cleanliness remained unchanged on floor treatments. A progressive increase in daily milk production/l (concrete: 13.37 ± 1.46, rubber: 16.67 ± 2.24, P = 0.007) of cows in rubber bedding was observed at the fourth week of the experiment. Hence, the current study suggests that the use of softer bedding such as rubber mats could improve cow comfort and daily milk production of cows.


Assuntos
Doenças dos Bovinos , Tarso Animal , Animais , Comportamento Animal , Bovinos , Doenças dos Bovinos/epidemiologia , Indústria de Laticínios , Feminino , Pisos e Cobertura de Pisos , Abrigo para Animais , Coxeadura Animal , Leite , Borracha , Sri Lanka
13.
J Agric Food Chem ; 69(38): 11382-11394, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34533305

RESUMO

Aromatized wines and regular table wines are often filled on the same bottling line. Sealing polymers in the filling line absorb volatiles from aromatized wines and may migrate due to insufficient cleaning into the subsequently bottled regular wine. Unintentional carryover of volatiles may lead to accusation of illegal aromatization of wine. Absorption, cleaning efficacy, and migration of volatiles into ethylene propylene diene monomer rubber were investigated in a model system. Direct thermal desorption-gas chromatography-mass spectrometry analysis of seven aroma compounds monitored variation in the polymer (µg/g). Absorption of volatiles was mostly driven by their octanol/water partition coefficients. Cleaning of polymers removed 11 to 62% of the absorbed volatiles. Subsequent immersion of cleaned polymers into model wine revealed migration of 20 to 57% of the remaining volatiles. Sensory tests suggested the impact of transferred volatiles into subsequent model wine. For α-ionone, an odor activity value of 1.03 indicated a potential sensory impact.


Assuntos
Compostos Orgânicos Voláteis , Vinho , Alcenos , Etilenos , Odorantes/análise , Polímeros , Borracha , Compostos Orgânicos Voláteis/análise , Vinho/análise
14.
Anal Chim Acta ; 1179: 338603, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34535249

RESUMO

Light-addressable potentiometric sensor (LAPS) has been widely used in biomedical applications since its advent. As a member of the potentiometric sensors, ion-sensitive LAPS (ISLAPS) can be obtained by modifying ion selective sensing membrane on the sensor surface. Compared with the conventional ion-selective electrodes (ISEs) with liquid contact, the all-solid-state ISEs have more advantages such as easy maintenance, more convenient for miniaturization and practical applications. However, the commonly used ion-sensitive membrane (ISM) matrix like PVC has many limitations such as poor adhesion to silicone-based sensor and easy overflow of the plasticizer from the membrane. In this work, LAPS was combined with a variety of ionophore-doped all-solid-state silicone-rubber ISMs for the first time, to establish a program-controlled multiplexed ISLAPS system for physiological ions (Na+, K+, Ca2+ and H+) detection. The silicone-rubber ISMs have better adhesion to silicon-based sensors without containing plasticizers, which can avoid the plasticizer pollution and improve the long-term stability. A layer of poly(3-octylthiophene-2,5-diyl) (P3OT) was pre-modified on the sensor surface to inhibit the formation of an aqueous layer and improve the sensor lifetime. With the aid of a translation stage, the light spot automatically illuminated the detection sites in sequence, and the response of the four ions could be obtained in one measurement within 1 min. The proposed multiplexed ISLAPS has good sensitivity with micromolar limit of detection (LOD), good selectivity and long-term stability (more than 3 months). The results of the real Dulbecco's Modified Eagle Medium (DMEM) sample detection proved that the ISLAPS system can be used for the physiological ions detection, and is promising to realize a multi-parameter microphysiometer.


Assuntos
Borracha , Elastômeros de Silicone , Eletrodos Íon-Seletivos , Íons , Potenciometria
15.
Plant Physiol Biochem ; 167: 376-384, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34404008

RESUMO

Ficus altissima Blume, a horticultural plant in tropical and warm subtropical regions, can produce natural rubber with comparable molecular weight to the Hevea brasiliensis rubber. The F. altissima latex has an acidic pH (about 4.89). The rubber particle size distribution is a unimodal profile, and the peak frequency is at a size of 4.5 µm. The natural rubber of F. altissima was determined to be a cis conformation via 13C NMR. The Mp (molecular weight of the peak maxima) of the deproteinized F. altissima rubber was 9.34 × 105 Da. LC-MS was used to identify the proteins of rubber particles and serum. The most abundant protein of the creamy rubber particle layer is an acid phosphatase, while the most abundant proteins of serum were an (R)-mandelonitrilelyase and a polygalacturonase inhibitor. Pharmaceutical proteins (ficins) or enzymes related to the biosynthesis of natural medicines (a cannabidiolic acid synthase and two lupeol synthase) were identified in F. altissima latex. The data of this study may be helpful for research on the functions of latex in latex-borne plants and the biosynthesis mechanism of natural rubber.


Assuntos
Ficus , Hevea , Látex , Proteínas de Plantas , Borracha
16.
Ned Tijdschr Geneeskd ; 1652021 05 12.
Artigo em Holandês | MEDLINE | ID: mdl-34346620

RESUMO

Washing hands and wearing gloves and face masks were introduced in surgery as part of an antiseptic and aseptic strategy in the second half of the 19th century. The aim was to prevent germs contaminating the wound in the patient operated on. However, when introduced in surgical practice, these measures were controversial. The need to wash hands was initially ignored. The first rubber gloves were omitted by many surgeons because they hampered 'tissue feel' in the fingers. There were doubts about the use of face masks because normal breathing would not form droplets that could contaminate the wound. Until the mid-20th century therefore, there were surgeons who did not wear gloves or face masks during surgery. Although wearing face masks during surgery is routine today, there is still no scientific evidence that this policy is effective in the prevention of surgical site infections.


Assuntos
Mãos , Máscaras , Humanos , Borracha , Infecção da Ferida Cirúrgica
17.
Langmuir ; 37(34): 10298-10307, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34406773

RESUMO

Soybean oil (SBO) is a renewable material used as an alternative to conventional petroleum-derived oils in the processing of rubber composites. Upon chemical modifications, such as epoxidation, its performance in the processing of rubber can be significantly improved, as indicated by a considerable reduction of the mixing energy. Although it has been hypothesized that hydrogen bonding between functional groups (e.g., epoxy) of SBOs and silanols present on the silica surface plays a key role, there is still a lack of direct evidence supporting this hypothesis. In this work, it is demonstrated that there is an overall correlation between the epoxy concentration of SBOs and the mixing energy, consistent with the long-held hypothesis. In particular, a correlation between the SBO-silica adsorption affinity and the degree of epoxidation is revealed by a set of surface-selective solid-state nuclear magnetic resonance (ssNMR) experiments. In addition, the surface-selective ssNMR technique demonstrated in this work could also be used to evaluate the adsorption affinity of other oils and/or additives more broadly.


Assuntos
Dióxido de Silício , Óleo de Soja , Adsorção , Espectroscopia de Ressonância Magnética , Borracha
18.
Neotrop Entomol ; 50(6): 899-911, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34398397

RESUMO

Livestock production extension in Amazon has caused deforestation and soil degradation, with negative consequences on diversity and environmental services. Recently, rubber crops have been established in deteriorated soils of the Colombian Amazon as an option to restore hectares of unproductive degraded pastures. Bioindicator insects, such as termites, have been used to assess soil quality and fertility restoration. This study evaluated differences in termite abundance, species richness, and community composition in three different rubber crop systems as an indirect way of evaluating soil diversity restoring. Three rubber crop systems were sampled: clonal fields (rubber monocultures with different rubber clones), traditional commercial rubber plantations (rubber monocultures with just one rubber clone), and mixed plantations (rubber fields intercropped with copoazú fruit trees). Additionally, pastures in use for livestock production and natural forest relicts were compared to rubber crop systems, to serve as reference habitats. Termites were sampled using a 105-m transect method. Alpha diversity and beta diversity were estimated and compared between rubber crops and reference habitats. A total of 80 termite species belonging to two families were collected. Mixed plantations and pastures presented the lowest diversity rates. Species richness in rubber crop systems was 39% higher than that in pastures and included 72% of the termite species found in natural forests. Indicator species analysis associated soil-feeding termites with less diverse habitats and wood-feeding termites with high diverse habitats. Our results demonstrate that termite recovery will depend on the farming system selected and the agricultural practices implemented in the field, with some rubber crop systems, like commercial rubber plantations and clonal fields, recovering termite diversity better than others, such as mixed plantations.


Assuntos
Isópteros , Animais , Colômbia , Florestas , Borracha , Solo , Árvores
20.
Water Res ; 202: 117457, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34358909

RESUMO

Microplastic particles in stormwater pose significant threats to the environment. This study investigated how effective a stormwater treatment train was at removing rubber, bitumen and other microplastics (incl. fibers, fragments, and paint particles) in the 100-300 µm and >300 µm size fractions from highway runoff. The two treatment trains comprise a gross pollutant trap (GPT) followed by either a vegetated bioretention cell or non-vegetated sand filter. Flow-proportional composite samples were taken from the highway runoff, GPT outflow and the outflow from the two parallel filters during nine rain events to determine overall treatment performance, as well as the performance of individual system components. The identified rubber, bitumen and other microplastic particles mainly represented the 100-300 µm fraction and included high ratios of rubber (30%) and bitumen (60%). Overall, the treatment train efficiently removed rubber, bitumen and other microplastic particles in the 100-300 µm size fraction from the stormwater. The filter cells accounted for a major share of this removal, as the GPT did not reduce microplastic particle concentrations. This observation is likely explained by the fact that the rubber, bitumen and other microplastic particles have a density close to the density of water and thus removal by sedimentation is decreased. This identified an inherent weakness of the system; more specifically, the high microplastic concentrations in the surface water of the GPT means there can be a risk of microplastic release through overflow pits when inflows surpass the system capacity. Despite some differences, both the vegetated bioretention cell and the non-vegetated sand filter removed rubber, bitumen and other microplastic particles to similar extent.


Assuntos
Poluentes Ambientais , Purificação da Água , Hidrocarbonetos , Microplásticos , Plásticos , Chuva , Borracha , Abastecimento de Água
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