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1.
PLoS Pathog ; 18(10): e1010926, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36306287

RESUMO

The emergence of Plasmodium falciparum parasite resistance to dihydroartemisinin + piperaquine (PPQ) in Southeast Asia threatens plans to increase the global use of this first-line antimalarial combination. High-level PPQ resistance appears to be mediated primarily by novel mutations in the P. falciparum chloroquine resistance transporter (PfCRT), which enhance parasite survival at high PPQ concentrations in vitro and increase the risk of dihydroartemisinin + PPQ treatment failure in patients. Using isogenic Dd2 parasites expressing contemporary pfcrt alleles with differential in vitro PPQ susceptibilities, we herein characterize the molecular and physiological adaptations that define PPQ resistance in vitro. Using drug uptake and cellular heme fractionation assays we report that the F145I, M343L, and G353V PfCRT mutations differentially impact PPQ and chloroquine efflux. These mutations also modulate proteolytic degradation of host hemoglobin and the chemical inactivation of reactive heme species. Peptidomic analyses reveal significantly higher accumulation of putative hemoglobin-derived peptides in the PPQ-resistant mutant PfCRT isoforms compared to parental PPQ-sensitive Dd2. Joint transcriptomic and metabolomic profiling of late trophozoites from PPQ-resistant or -sensitive isogenic lines reveals differential expression of genes involved in protein translation and cellular metabolism. PPQ-resistant parasites also show increased susceptibility to an inhibitor of the P. falciparum M17 aminopeptidase that operates on short globin-derived peptides. These results reveal unique physiological changes caused by the gain of PPQ resistance and highlight the potential therapeutic value of targeting peptide metabolism in P. falciparum.


Assuntos
Antimaláricos , Artemisininas , Malária Falciparum , Parasitos , Animais , Humanos , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Cloroquina/farmacologia , Cloroquina/metabolismo , Parasitos/metabolismo , Proteínas de Protozoários/metabolismo , Resistência a Medicamentos/genética , Malária Falciparum/tratamento farmacológico , Malária Falciparum/genética , Malária Falciparum/parasitologia , Antimaláricos/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Artemisininas/farmacologia , Mutação , Hemoglobinas/metabolismo , Heme/metabolismo
2.
J Environ Manage ; 301: 113913, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34731942

RESUMO

In-situ burning can be used to prevent oil spreading in oil spill response. In this study, a steady-state Gaussian plume model was applied to analyze the concentration distribution of fine particulate matter produced by in-situ burning, as well as to assess the health risks associated with different combustion methods and ambient conditions, in reference to three simulation scenarios. The spatial and temporal distribution of emission sources can affect the dispersion pattern. The distribution into an array of different burning locations ensures better dispersion of emissions, thereby preventing the formation of high concentration regions. The wind and atmosphere stability play an important role in pollution dispersion. Lower wind and temperature inversion can seriously hinder the diffusion of pollutants. The health risk to technical staff adjacent to the burning areas is a serious concern, and when the community is more than 20 km away from the burning zone, there is few risks. Through simulation, the influences of combustion methods and natural factors on the concentration and diffusion of pollutants are evaluated. The results can help provide an optimized burning strategy for oil spill response in the Arctic area.


Assuntos
Poluentes Atmosféricos , Poluição por Petróleo , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Humanos , Material Particulado/análise , Vento
3.
J Manipulative Physiol Ther ; 45(7): 497-507, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36922054

RESUMO

OBJECTIVES: The primary purposes of this study were to measure axial rotation during supine cervical spinal manipulative therapy (cSMT) and to record recipients' and doctors' perceptions of rotational magnitudes. METHODS: Experienced doctors of chiropractic (DCs) provided supine cSMT and acted as recipients of cSMT. Participants who received SMT wore inertial measurement units attached to the forehead and sternum for motion capture. Afterward, recipients and DCs completed questionnaires asking about their perceptions of motion. Data were analyzed for magnitudes of axial rotation at peak thrust and correlations with patient and doctor perceptions. Secondary analyses included angular velocity, angular acceleration, and other kinematic variables. RESULTS: We recorded 23 SMT events with 14 DCs. Rotation at thrust peaks averaged 32.4° (17.4°). Doctors' and recipients' perceptions of rotation were higher than measured values 45% and 50% of the time, respectively. Maximum angular velocity and acceleration averaged 221.9°/s (124.9) and 4786.5°/s2 (2456.6), respectively. We found no correlation between perceptions and velocity or acceleration; doctors' perceptions had an inverse correlation with measurements. CONCLUSION: On average, we found rotation during supine cSMT to be 32°. Both DCs and SMT recipients overestimated rotation compared with actual measurements. These factors should be considered in discussions of rotation and SMT.


Assuntos
Quiroprática , Manipulação Quiroprática , Manipulação da Coluna , Humanos , Fenômenos Biomecânicos , Rotação , Vértebras Cervicais
4.
J Manipulative Physiol Ther ; 45(4): 298-314, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-36057479

RESUMO

OBJECTIVE: The purpose of this study was to develop a protocol and a data analysis system for the assessment of postures and movements of doctors of chiropractic during side-posture adjustments (SPAs), otherwise known as side-posture chiropractic spinal manipulation. METHODS: For this study, an experienced chiropractor performed Gonstead-style lumbar SPAs on 10 participants. We used an inertial measurement unit system to record spinal angular motions and analyzed data with a custom application written in Microsoft Excel. RESULTS: Data collection was successful for all trials. We identified postural angles at the time of set-up and thrust and maximum and minimum angles in a period centered on the thrust. All spinal regions of the chiropractor were flexed during the entire period; otherwise, movement patterns were characterized by biphasic wavelike motions, which begin before the time of the thrust and finish afterward. Within each region and plane of motion, patterns were qualitatively similar between participants, but time of thrust was not consistent within the patterns. There was a wide range of angular velocities, and the fastest was measured in the chiropractor's cervical and thoracic regions. CONCLUSION: In this study, we developed a protocol and a data analysis system for assessment of chiropractors' postures and movements during SPAs. The protocol may be useful to future investigators who wish to use similar methods for educational purposes or to examine the role of optimal or suboptimal movement patterns in occupational injuries of doctors of chiropractic.


Assuntos
Quiroprática , Manipulação Quiroprática , Fenômenos Biomecânicos , Humanos , Região Lombossacral , Postura
5.
J Environ Manage ; 279: 111637, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33340963

RESUMO

The Shoreline Response Program (SRP) is an adjustment within an Incident Management System (IMS) intended to improve current practices during planning and preparedness for and from the initial response to an oil spill. An SRP builds on the recognized strengths of an IMS-based organization and of a Shoreline Cleanup Assessment Technique (SCAT) program that utilizes an integrated and focused approach to streamline and better coordinate the decision and planning processes and the operational implementation activities. An SRP is an extension of the traditional SCAT program but with a broader focus on strategic and tactical planning to minimize the short- and long-term impacts of oil on shorelines, the efforts and costs involved in a shoreline response, and the volumes of waste that would be generated. The objective of this discussion is to identify and address five specific areas for improvement in the shoreline component of an IMS that are associated with the separation of responsibility, streamlining the Environmental Unit (EU), internal communications, Operations support and training. These improvements essentially constitute a paradigm shift and are described in the context of the integration of an SRP into the IMS, the relationship between an SRP and the Environmental Unit, and the enabling of a more formal support approach to the Operations Section by an SRP SCAT-OPS Liaison program. The inclusion of an SRP concept in drills, exercises and preparedness training can directly change the management culture and improve the ability to respond quickly and effectively during the initial response phase. Not implementing an SRP at the very outset of a spill response, when typically the best opportunities exist for the removal of bulk oil, can have significant long-term consequences. Shifting an emphasis of management and physical resources from, often only partially successful, on-water activities to onshore shoreline activities when oil can be picked up more rapidly and effectively can significantly reduce i) the footprint of the response, ii) the duration and scale of the shoreline operation, iii) the exposure of shore zone resources to the oil, and so accelerates ecological and socio-economic recovery. The concept of an SRP as an integrated "single point of contact" for all shoreline-related issues and activities is likely to become more significant as IMS models evolve with potentially fewer people in a more decentralized Command Post and with a greater number of IMS planners, managers, and decision-makers participating from remote locations and/or in a virtual environment.


Assuntos
Poluição por Petróleo , Humanos , Inquéritos e Questionários
6.
J Environ Manage ; 296: 113240, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34271360

RESUMO

Coastal environment is one of the most important ecological and socioeconomic areas. However, increasing energy demand and economic development lead to a continuous gas and oil exploration, production, and traffics, which notably raise the risk of oil spill accidents in coastal areas. Sensitivity assessment aiming to determine the coastal features that would be severely impaired by spill incidents is a crucial part of the response planning. In this study, an innovative framework for coastal sensitivity mapping that incorporated ecosystem service (ES) valuation and multidimensional assessment was proposed. Sensitivity was computed by valuing physical, biological, and social-economical indicators from ES perspective and separating each indicator into specific coastal domains. For different ES typologies, provisioning services contributed most to the overall ES value followed by culture services, supporting services, and regulating services. For ES value in different coastal domains, the highest value was recorded in the water column followed by water surface, shoreline, and seabed. However, the shoreline ranked highest regarding the ES value per ha. Sensitivity assessment revealed that sensitive areas differed in different domains, both in distribution and extent. Compared with the scoring method, the ES valuation method showed more coincidence with Ecologically and Biologically Significant Areas (EBSA), representing a more precise and practical approach for sensitivity assessment. A three-dimensional (3D) oil spill model was also applied to generate maps of oil contamination probability in shoreline, water surface, and water column. The obtained results highlighted the significance of incorporating different coastal domains into oil spill responses, and the urgent demand to broaden and deepen our understanding of ecological processes across the vertical coastal zones.


Assuntos
Poluição por Petróleo , Poluentes Químicos da Água , Canadá , Ecossistema , Monitoramento Ambiental , Poluentes Químicos da Água/análise
7.
J Environ Manage ; 287: 112346, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33756213

RESUMO

The shorelines frequently suffer adverse impacts from oil spill accidents. As one important technique of shoreline cleanup, the application of surface washing agents (SWAs) can help achieve high oil removal from shoreline substrates with less damage to affected zone. In this study, a framework for evaluation and selection of SWAs in oil spill incidents was constructed to better understand and apply this technique. A decision tree was firstly developed to illustrate all possible scenarios which are appropriate to use SWAs in consideration of oil collectability, shoreline character, types and amount of stranded oil, and cleanup requirement. Based on literature review, theoretical modeling, and experts' suggestions, an integrated multi-criteria decision analysis (MCDA) method was then come up to select the most preferred SWA from five aspects of toxicity, effectiveness, minimal dispersion, demonstrated field test, and cost. Its suitability and rationality were proved by a hypothetical case. In addition, sensitivity analysis was performed by changing the weight of each criterion independently to check the priority rank of alternatives, and it also verified the robustness and stability of this model. The presented framework has significant implications for future research and application of SWAs in the shoreline cleanup.


Assuntos
Poluição por Petróleo , Acidentes
8.
J Infect Dis ; 221(6): 956-962, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-31616928

RESUMO

Spreading antimalarial resistance threatens effective treatment of malaria, an infectious disease caused by Plasmodium parasites. We identified a compound, BCH070, that inhibits asexual growth of multiple antimalarial-resistant strains of Plasmodium falciparum (half maximal inhibitory concentration [IC50] = 1-2 µM), suggesting that BCH070 acts via a novel mechanism of action. BCH070 preferentially kills early ring-form trophozoites, and, importantly, equally inhibits ring-stage survival of wild-type and artemisinin-resistant parasites harboring the PfKelch13:C580Y mutation. Metabolomic analysis demonstrates that BCH070 likely targets multiple pathways in the parasite. BCH070 is a promising lead compound for development of new antimalarial combination therapy that retains activity against artemisinin-resistant parasites.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/administração & dosagem , Antimaláricos/química , Células Cultivadas , Resistência a Medicamentos , Fibroblastos/parasitologia , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos
9.
J Environ Manage ; 275: 111232, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829266

RESUMO

Spilled oil frequently reaches the shorelines and affects coastal biota and communities. The application of surface washing agents is an important shoreline cleanup technique that can help remove stranded oil from substrate surfaces with the advantages of high removal efficiency, low toxicity, and strong economic viability. In this study, the investigation into the oil removal from contaminated sand using a surface washing agent under variable environmental conditions was conducted. A preliminary test was conducted to obtain the optimal combination of operating factors of surface washing agent-to-oil ratio (SOR) 2:1, mixing speed 150 rpm, and mixing time 30 min. The results of single-factor experiments showed that high temperature and humic acid concentration of flush water contributed to the performance of a surface washing agent, while salinity and kaolinite concentration could inhibit its performance. The factorial analysis revealed the main effects of temperature and salinity, and the interactive effects of temperature and salinity as well as salinity and humic acid concentration that were significant to the washing efficiency of the surface washing agent. In addition, the comprehensive assessment of a surface washing agent from the aspects of toxicity, detergency, dispersion properties, and field trials was conducted. The results have significant implications for future application of surface washing agents in the shoreline cleanup.


Assuntos
Petróleo , Poluentes Químicos da Água , Salinidade , Areia , Temperatura , Poluentes Químicos da Água/análise
10.
J Manipulative Physiol Ther ; 40(6): 411-419, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28645452

RESUMO

OBJECTIVES: The purpose of this study was to measure faculty performance of simulated spinal manipulation on a mannequin to help identify teaching standards. METHODS: We measured 3-dimensional transmitted loads using a force plate mounted in the table. Thrusts were delivered through a compliant, jointed mannequin by faculty members along predefined "listings" as taught in lumbopelvic technique courses. RESULTS: Eleven chiropractic faculty members participated, delivering 9 thrusts at 3 loads (light, moderate, and heavy) along 9 different prone and side-posture listings, totaling 81 thrusts per participant. Single-hand Gonstead-style thrusts had variability in magnitude across participants and loads: light thrusts averaged 365 N (95% confidence interval [CI] 327-402), moderate thrusts 454 N (421-487), and heavy thrusts 682 N (623-740). All faculty members could easily distinguish the loads within their performances, but there was some crossover of load levels between participants. Thrust rates averaged 3.55 N/ms (95% CI 3.29-3.82). The dominant vector of prone thrusts was in the z direction (vertically downward), but side-to-side and inferior-to-superior vector components occurred. CONCLUSION: Faculty member performance of simulated spinal manipulation indicated that they are able to control the thrust magnitude and rate as well as direction. In this sample, there was significant variability in peak loads between participants, which needs to be considered in student learning standards. These findings may be useful in translating the understanding of force characteristics to the technique teaching lab.


Assuntos
Quiroprática/educação , Força Compressiva , Imageamento Tridimensional , Manipulação da Coluna/métodos , Treinamento por Simulação/métodos , Fenômenos Biomecânicos , Estudos de Coortes , Feminino , Humanos , Região Lombossacral , Masculino , Manequins , Sensibilidade e Especificidade , Análise e Desempenho de Tarefas
11.
J Manipulative Physiol Ther ; 36(6): 342-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23830714

RESUMO

OBJECTIVES: The objectives of this study were to examine the force-time profiles of toggle recoil using an instrumented simulator to objectively measure and evaluate students' skill to determine if they become quicker and use less force during the course of their training and to compare them to course instructors and to field doctors of chiropractic (DCs) who use this specific technique in their practices. METHODS: A load cell was placed within a toggle recoil training device. The preload, speed, and magnitude of the toggle recoil thrusts were measured from 60 students, 2 instructors, and 77 DCs (ie, who use the toggle recoil technique in their regular practice). Student data were collected 3 times during their toggle course (after first exposure, at midterm, and at course end.) RESULTS: Thrusts showed a dual-peak force-time profile not previously described in other forms of spinal manipulation. There was a wide range of values for each quantity measured within and between all 3 subject groups. The median peak load for students decreased over the course of their class, but they became slower. Field doctors were faster than students or instructors and delivered higher peak loads. CONCLUSION: Toggle recoil thrusts into a dropping mechanism varied based upon subject and amount of time practicing the task. As students progressed through the class, speed reduced as they increased control to lower peak loads. In the group studies, field DCs applied higher forces and were faster than both students and instructors. There appears to be a unique 2-peak feature of the force-time plot that is unique to toggle recoil manipulation with a drop mechanism.


Assuntos
Quiroprática/educação , Manipulação da Coluna/métodos , Fenômenos Biomecânicos , Humanos , Materiais de Ensino , Fatores de Tempo
12.
J Chiropr Educ ; 37(2): 73-81, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37721390

RESUMO

OBJECTIVE: Force-sensing treatment tables are becoming more commonly used by chiropractic educational institutions. However, when a table-embedded force platform is the sole measurement method, there is little information available about what force-time values instructors and students should expect for side-posture spinal manipulative thrusts. The purpose of this report is to provide force-time values recorded with such a system during side-posture manipulation with human recipients. METHODS: Student volunteers were examined by and received lumbar or pelvic side-posture manipulation from experienced chiropractors who were diplomates of the Gonstead Clinical Studies Society. Forces were recorded using proprietary software of a Bertec force platform; force and time data were analyzed with a custom-programmed software tool in Excel. RESULTS: Seven doctors of chiropractic performed 24 thrusts on 23 student recipients. Preload forces, averaging 69.7 N, and thrust loading duration, averaging 167 milliseconds, were similar to previous studies of side-posture manipulation. Peak loads were higher than previous studies, averaging 1010.9 N. Other variables included prethrust liftoff force, times from thrust onset to peak force and peak load to resolution of thrust, and average rates of force loading and unloading. CONCLUSION: The values we found will be used for reference at our institution and may be useful to instructors at other chiropractic educational institutions, in the teaching of lumbar side-posture manipulation. A caveat is that the values of this study reflect multiple sources of applied force, not solely the force applied directly to the spine.

13.
J Chiropr Educ ; 36(2): 147-152, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35394042

RESUMO

OBJECTIVE: Faced with COVID-19 safety protocols that severely limited the ability to conduct chiropractic technique instruction in the usual manner, our university invested the resources to develop a new mannequin lab for hands-on training, which would help supplement the loss of person-to-person contact. METHODS: Training mannequins could enable student learning of palpation and adjustment skills while avoiding close human-human contact. The university had developed a mannequin over the previous 4 years consisting of a full-sized human torso with individually movable and palpable vertebrae, pelvis, and thighs. In the mannequin, 64 pressure sensors are attached to particular vertebral and skeletal landmarks and provide feedback on palpation location and level of force applied. We assembled 3 teams to produce 20 copies of that mannequin for student use. RESULTS: Mannequins were produced in 7 weeks, and space was built out for a special lab. Faculty members are developing classroom procedures to introduce the mannequin to students, phase in the skills from static and motion palpation, and practice thrust performance. CONCLUSION: The production run was successful, and the resulting equipment, well-received by students and faculty. In addition to helping teach manual skills, the lab serves as a platform for educational research to test the efficacy of mannequin-based training protocols. With the pressure sensors on known locations along the spine, future research may be able to test the ability of students to identify and contact specific target locations for adjustive thrusts.

14.
J Hazard Mater ; 437: 129341, 2022 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-35738169

RESUMO

Mineral fines act a pivotal part in determining the fate and behavior of oil. In this study, the infiltrations of oil emulsion in simulated sediments and natural shoreline sediments were investigated using a fixed bed experiment. Oil infiltration process was simulated based on fixed-bed dispersion model. The role of mineral fines in oil release was explored using simulated and natural sediments. Although mineral fines exhibited a higher affinity for oil, it was found that increasing fines fractions decreased the flow rate of oil emulsion, thereby decreasing the oil retention in the sediment column. In terms of oil release from the sediment, the highest level of oil mass was observed in the oil-mineral flocculation phase compared to the water column and the water surface compartments. Compared to light crude oil, the release of engine oil from sediment was less. The effects of mineral fines on oil infiltration and release were also confirmed by using natural shoreline sediments. Results of our detailed field studies also showed that current shoreline classification datasets do not characterize the presence and fraction of mineral fines at a level of detail required to accurately predict the significance of oil translocation following spill incidents.


Assuntos
Poluição por Petróleo , Petróleo , Poluentes Químicos da Água , Emulsões , Sedimentos Geológicos/química , Minerais/química , Petróleo/análise , Poluição por Petróleo/análise , Água/análise , Poluentes Químicos da Água/química
15.
J Hazard Mater ; 436: 129228, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35739748

RESUMO

It is well known that oil stranded on shoreline substrates can be difficult to remove and cause serious environmental effects. To address this issue, a calcium alginate-cellulose nanocrystal (CA-CNC)-based coating with a unique surface structure and superhydrophobic properties was developed to reduce the extent of shoreline oiling. The results of batch washing test showed that not only did the introduction of CNC not reduce the oil removal efficiency; it also improved the environmental stability of the coating to resist the effects associated with seawater immersion and erosion (especially in the case of 0.4 wt% of CNC). The oil-repellent performance of the coated gravels implied that both oscillation time and oil concentration had almost no effects on the amount of adhered oil. Assessment of oiling prevention based on the laboratory shoreline tank simulator proved the coated gravel performed very well as more oil floated and less oil remained on substrates and penetrated into the subsurface. Biotoxicity analysis showed that the coating powders reduced impacts on the toxicity of the oil to algae at low doses. There is a good potential for the use of this CA-CNC based coating technique to improve shoreline oil spill response.


Assuntos
Nanopartículas , Poluição por Petróleo , Poluentes Químicos da Água , Alginatos , Celulose , Poluição por Petróleo/análise , Poluentes Químicos da Água/química
16.
J Manipulative Physiol Ther ; 34(9): 594-601, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22078998

RESUMO

OBJECTIVE: The purpose of this study was to assess back muscle status at baseline in patients with back-related leg pain (BRLP) and to correlate those findings with baseline demographic and clinical factors. METHODS: Surface electromyography (EMG) and electromagnetic motion-tracking detected flexion-relaxation response in 135 patients with BRLP. Surface EMG electrodes were attached with standard skin preparation over the right and left paraspinal muscles at L3. Participants moved from upright standing into full forward flexion, rested flexed for 1 second, and returned to the upright position. A flexion-relaxation ratio (FRR) factor was calculated as the root mean square EMG amplitude during forward flexion divided by the activity at full flexion. RESULTS: High repeatability was found (intraclass correlation coefficient [ICC]([1,3]) = 0.94 and 0.86) between 3 cycles of assessment at the same session. Patients with BRLP exhibited low FRR values, indicating a loss of the flexion-relaxation response similar to that seen in low back pain patients. Patients with very low FRR had higher Roland-Morris Disability Questionnaire scores than the other patients, had increased incidence of straight leg raise test, and had decreased range and rate of forward flexion. CONCLUSIONS: A subgroup of patients with BRLP was identified with very low FRR who exhibited more disability and clinical findings and decreased motion. The use of the inverted FRR factor, expressing muscle activity at the fully flexed and resting position as a percentage of peak activity during flexion, provides more stable numerical behavior and another perspective on interpreting FRRs.


Assuntos
Perna (Membro) , Dor Lombar/fisiopatologia , Relaxamento Muscular , Músculo Esquelético/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Eletromiografia , Humanos , Pessoa de Meia-Idade
17.
Artigo em Inglês | MEDLINE | ID: mdl-33638067

RESUMO

This study focused on the impact of microalgal biomass on the oil behavior in a sand-water system. The microalgal biomass was characterized, and the interaction between microalgal biomass and oil was analyzed through Fourier transform infrared (FTIR) spectroscopy. The effects of different conditions including microalgal biomass dose, pH, temperature, and salinity on the oil behavior were investigated. A two-level factorial analysis was also used to further explore the interactions of these conditions. The microalgal biomass was found to be the most influential parameter for the residual crude oil on sand. Higher microalgal biomass dose resulted in less residual oil on sand. The remaining oil decreased with increasing solution pH from 4 to 7, and an increase of remaining oil was observed when the pH was further increased above 7. In addition, temperature and salinity could affect the removal of crude oil in the presence of microalgal biomass. Increasing the temperature could result in less residual oil on sand and there was higher oil removal at the high salinity. The effects of microalgal biomass on the oil behavior could also be impacted by environmental conditions. The results of this study indicate that the presence of algae in the oiled shoreline can be considered in the comprehensive evaluation of spill risk and prediction of oil fate.

18.
J Chiropr Educ ; 35(1): 1-7, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32930327

RESUMO

OBJECTIVE: To test the posterior-to-anterior stiffness (PAS) of a new thoracic spine training simulator under different conditions of "fixation." METHODS: We constructed a thoracic spine model using plastic bones and ribs mounted in a wooden box, with skin and soft tissue simulated by layers of silicone and foam. The spine segment could be stiffened with tension applied to cords running through the vertebrae and ribs. We tested PAS at 2 tension levels using a custom-built device to apply repetitive loads at the T6 spinous process (SP) and over adjacent soft tissue (TP) while measuring load and displacement. Stiffness was the slope of the force-displacement curve from 55 to 75 N. RESULTS: Stiffness in the unconstrained (zero tension) condition over the SP averaged 11.98 N/mm and 6.72 N/mm over the TP. With tension applied, SP stiffness increased to 14.56 N/mm, and TP decreased to 6.15 N/mm. CONCLUSION: Thoracic model compliance was similar to that reported for humans. The tension control system increased stiffness by 21.3% only over the SP. Stiffness over the TP was dominated by the lower stiffness of the thicker foam layer and did not change. The mannequin with these properties may be suitable for use in manual training of adjusting or PAS testing skills.

19.
J Hazard Mater ; 402: 123464, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-32693337

RESUMO

Surface-washing agents are an option to enhance the removal of oil spilled or stranded on shorelines. The use of nanocellulose-based nanofluid as a surface-washing agent was studied by investigating its reactivity and effectiveness. Salinity was found to be the most influencial factor to facilitate oil removal with the nanofluids. Cations from salt can promote the adsorption of nanocellulose on the oil/water interface by reducing the surface charges. The experimental results revealed the nanocellulose could be effective at low concentrations but an excess of nanocellulose hindered oil removal due to an increase in fluid viscosity. A miscibility model was applied to verify this finding in a thermodynamics context. The biotoxicity tests showed that nanocellulose-based nanofluid did not have negative effects on algae growth and introducing nanocellulose into an oiled culture medium can actually mitigate the toxicity of the oil on algae. A comparison in removal efficiency with other surfactants demonstrated the potential value for shoreline cleanup due to the superior effectiveness of nanocellulose-based nanofluids. Overall, a nanocellulose has a high potential for application as a surface-washing agent for shoreline cleanup due to the low cost, low toxicity, and high efficiency.


Assuntos
Celulose , Nanopartículas , Plantas , Salinidade , Tensoativos
20.
Mar Pollut Bull ; 167: 112313, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33839574

RESUMO

Marine oil spills pose a significant threat to ocean and coastal ecosystems. In addition to costs incurred by response activities, an economic burden could be experienced by stakeholders dependent on coastal resources. Decision support tools for oil spill response (OSR-DSTs) have been playing an important role during oil spill response operations. This paper aims to provide an insight into the status of research on OSR-DSTs and identify future directions. Specifically, a systematic review is conducted including an examination of the advantages and limitations of currently applied and emerging decision support techniques for oil spill response. In response to elevated environmental concerns for protecting the polar ecosystem, the review includes a discussion on the use of OSR-DSTs in cold regions. Based on the analysis of information acquired, recommendations for future work on the development of OSR-DSTs to support the selection and implementation of spill response options are presented.


Assuntos
Poluição por Petróleo , Ecossistema
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