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1.
Environ Sci Pollut Res Int ; 27(12): 12851-12865, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30734255

RESUMO

In order to avoid the production of sulfates and nitrates in marine diesel engines that burn sulfur-containing fuels, the operating temperature of their high-pressure selective catalytic reduction (HP-SCR) systems should be higher than 320 °C. For marine low-speed diesel engines, only the pre-turbine exhaust gas temperature can meet this requirement under specific conditions, with the main engine modulation method helping to increase the exhaust gas temperature. However, the main engine modulation method brings down the power output and fuel economy of the main engine and causes the matching problem of the turbine and the other devices with the main engine. The original engine model of the marine low-speed diesel engine and the high-pressure SCR system configuration model have been constructed using one-dimensional simulation software. In addition, the performance of the high-pressure SCR system under the conditions of low-sulfur and high-sulfur exhaust gas was thoroughly analyzed. Moreover, the two main engine modulation schemes of the scavenging bypass and the turbine exhaust bypass of the original engine matching with the high-pressure SCR system were studied. The study found that the weighted average value of the NOx under the condition of low-sulfur exhaust gas met with the requirement of the IMO Tier III regulations when the low-speed diesel engine was matched with the high-pressure SCR system. However, the weighted average value of the NOx under the condition of high-sulfur exhaust gas was slightly higher than that required by the IMO Tier III regulation. In addition, the optimal main engine modulation scheme for this low-speed diesel engine was clarified by comparing the effects of the scavenging bypass and the turbine exhaust bypass modulation on the exhaust performance, and the working performance of the original engine. With an opening of 0.4 of the CBV valve under 25% engine load, the weighted average NOx of the original exhaust gas was 3.38 g/(kW·h), the power had decreased by 0.7%, and the fuel consumption had increased by 1.0%. Furthermore, when the EGB valve opening was 0.3, the weighted average value of NOx was 3.31 g/(kW·h), the power had reduced by 2.4% and the fuel consumption had increased by 2.5%. Both modulation scheme methods made the exhaust performance of the original engine meet the requirements of the IMO Tier III emission regulations, but the scavenging bypass modulation scheme had less impact on the original engine's performance.

2.
Sci Total Environ ; 706: 135444, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31862600

RESUMO

Exhaust gas recirculation (EGR) can be widely used to reduce the oxynitride (NOx) pollution in Low-Speed Two-Stroke Marine Diesel Engines. In this paper, two EGR systems (HP EGR1 and LP EGR2) were investigated in terms of the influence of different rates on the brake specific fuel consumption (BSFC) and the NOx emissions. As for this simulation, the exhaust gas cleaning water treatment was not concluded. Besides, Miller Cycle was used to determine the influence of its valve timing on BSFC and NOx emissions. The combination of Miller Cycle and HP EGR system decreased the NOx emissions, which could meet the IMO3 Tier III standard, 3.4 g/kWh. Moreover, the influence of the EGR cooling temperature was discussed. Finally, a fuzzy comprehensive evaluation model was developed to evaluate the two EGR systems. The results showed that when the HP EGR system and the LP EGR system were all operating at a maximum EGR rate, LP EGR system showed more advantages.

3.
Electrophoresis ; 39(12): 1460-1465, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29543983

RESUMO

This work presents a simple, low-cost method to fabricate semi-circular channels using solder paste, which can amalgamate the cooper surface to form a half-cylinder mold using the surface tension of Sn-Pd alloy (the main component in solder paste). This technique enables semi-circular channels to be manufactured with different dimensions. These semi-circular channels will then be integrated with a polymethylmethacrylate frame and machine screws to create miniaturized, portable microfluidic valves for sequential liquid delivery and particle synthesis. This approach avoids complicated fabrication processes and expensive facilities and thus has the potential to be a useful tool for lab-on-a-chip applications.


Assuntos
Microfluídica , Ligas/química , Desenho de Equipamento/instrumentação , Dispositivos Lab-On-A-Chip , Paládio/química , Tensão Superficial , Estanho/química
4.
Electrophoresis ; 39(7): 957-964, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29292831

RESUMO

Proteinuria is an established risk marker for progressive renal function loss and patients would significantly benefit from a point-of-care testing. Although extensive work has been done to develop the microfluidic devices for the detection of urinary protein, they need the complicated operation and bulky peripherals. Here, we present a rapid, maskless 3D prototyping for fabrication of capillary fluidic circuits using laser engraving. The capillary circuits can be fabricated in a short amount of time (<10 min) without the requirements of clean-room facilities and photomasks. The advanced capillary components (e.g., trigger valves, retention valves and retention bursting valves) were fabricated, enabling the sequential liquid delivery and sample-reagent mixing. With the integration of smartphone-based detection platform, the microfluidic device can quantify the urinary protein via a colorimetric analysis. By eliminating the bulky and expensive equipment, this smartphone-based detection platform is portable for on-site quantitative detection.


Assuntos
Técnicas Analíticas Microfluídicas/métodos , Proteinúria/urina , Smartphone/instrumentação , Estereolitografia , Colorimetria/métodos , Desenho de Equipamento/instrumentação , Humanos , Imagem Óptica/instrumentação , Processos Fotoquímicos , Polimetil Metacrilato/química , Soroalbumina Bovina/química , Propriedades de Superfície
5.
Nanoscale Res Lett ; 12(1): 289, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28438010

RESUMO

The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}<001>. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}<001>, {110}<1-10>, and {111}<1-10>, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

6.
Environ Microbiol ; 17(5): 1600-14, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25142282

RESUMO

Archaea can respond to changes in the environment by altering the composition of their membrane lipids, for example, by modification of the abundance and composition of glycerol dialkyl glycerol tetraethers (GDGTs). Here, we investigated the abundance and proportions of polar GDGTs (P-GDGTs) and core GDGTs (C-GDGTs) sampled in different seasons from Tengchong hot springs (Yunnan, China), which encompassed a pH range of 2.5-10.1 and a temperature range of 43.7-93.6°C. The phylogenetic composition of the archaeal community (reanalysed from published work) divided the Archaea in spring sediment samples into three major groups that corresponded with spring pH: acidic, circumneutral and alkaline. Cluster analysis showed correlation between spring pH and the composition of P- and C-GDGTs and archaeal 16S rRNA genes, indicating an intimate link between resident Archaea and the distribution of P- and C-GDGTs in Tengchong hot springs. The distribution of GDGTs in Tengchong springs was also significantly affected by temperature; however, the relationship was weaker than with pH. Analysis of published datasets including samples from Tibet, Yellowstone and the US Great Basin hot springs revealed a similar relationship between pH and GDGT content. Specifically, low pH springs had higher concentrations of GDGTs with high numbers of cyclopentyl rings than neutral and alkaline springs, which is consistent with the predominance of high cyclopentyl ring-characterized Sulfolobales and Thermoplasmatales present in some of the low pH springs. Our study suggests that the resident Archaea in these hot springs are acclimated if not adapted to low pH by their genetic capacity to effect the packing density of their membranes by increasing cyclopentyl rings in GDGTs at the rank of community.


Assuntos
Archaea/metabolismo , Sedimentos Geológicos/microbiologia , Éteres de Glicerila/metabolismo , Fontes Termais/microbiologia , Lipídeos de Membrana/metabolismo , Archaea/genética , Desulfurococcales/genética , Desulfurococcales/isolamento & purificação , Meio Ambiente , Éteres de Glicerila/análise , Concentração de Íons de Hidrogênio , Lipídeos de Membrana/análise , Oxigênio/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Estações do Ano , Microbiologia do Solo , Sulfolobales/genética , Sulfolobales/isolamento & purificação , Temperatura , Thermoplasmales/genética , Thermoplasmales/isolamento & purificação , Tibet
7.
FEBS Lett ; 586(7): 1038-43, 2012 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-22569260

RESUMO

In HCT116 colorectal cancer cells, HeLa cervical cancer cells and HuH-7 hepatoma cells, miR-223 is expressed at a low level. Through infection with lentivirus containing miR-223 precursor, miR-223 [corrected] was overexpressed in all these cells. Interestingly, the expression levels of FOXO1 mRNA and protein, and phosphorylation levels became significantly lower than those of their control. FOXO1 was down-regulated mainly in the cytoplasm, while the nuclear FOXO1 level became relatively high compared to the cytoplasm. As the unphosphorylated active form of FOXO1 increased in the cells, cyclin D1/p21/p27 were up-regulated at either mRNA or protein level. Proliferation of the cells was also greatly inhibited when miR-223 was over-expressed. Therein, our data suggest that miR-223 regulates FOXO1 expression and cell proliferation.


Assuntos
Proliferação de Células , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , MicroRNAs/fisiologia , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Linhagem Celular Transformada , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Neoplasias Colorretais/metabolismo , Ciclina D1/genética , Ciclina D1/metabolismo , Proteínas Inibidoras de Quinase Dependente de Ciclina/genética , Proteínas Inibidoras de Quinase Dependente de Ciclina/metabolismo , Citoplasma/metabolismo , Feminino , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/genética , Humanos , Neoplasias Hepáticas/metabolismo , Masculino , MicroRNAs/biossíntese , MicroRNAs/genética , Proteínas de Neoplasias/genética , Fosforilação , Processamento de Proteína Pós-Traducional , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Neoplasias do Colo do Útero/metabolismo
8.
Zhonghua Liu Xing Bing Xue Za Zhi ; 32(1): 17-9, 2011 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-21518534

RESUMO

OBJECTIVE: To study the relevant factors on an measles outbreak caused by imported new virus (d11 genotype) from Myanmar and to develop effective strategies and measures. METHODS: On-site investigation on the outbreak was carried out. RESULTS: There were four townships (66%) in Menglian county reported 15 cases of measles, with 7 cases aged 6 months to 5 years old, 2 cases with the history of measles vaccination (MV). Another 8 cases were 21 to 49 year-olds but their histories on immunization were unclear. 14 of the measles cases with Myanmar citizenship came to China for treatment. They were aged 10 months to 13 years old, with only one case had ever received MV vaccination. For all the 29 cases, except for one case who did not adopt the sample case of Myanmar, the remaining 28 patients were positive for measles IgM antibodies. 6 cases of measles virus RNA were detected in the amplified sequence which showed genotype d11, and was considered Myanmar imported wild virus. 184 people received the MV inoculation, with a rate of 61.96% and the serum samples showed a measles IgG antibody positive rate of 87.50%. Manner MV emergency vaccination was carried out timely in that county so the measles outbreak was effectively controlled. CONCLUSION: Imported measles cases from foreign countries might lead to epidemic, indicating the difficulty and challenge in the elimination of measles in our province. Emergent vaccination of MV could interrupt the transmission of the disease. Our experience showed that MV was effective in the prevention of d11 genotypes measles infection in the area.


Assuntos
Surtos de Doenças , Vírus do Sarampo/genética , Sarampo/epidemiologia , Sarampo/virologia , Adolescente , Adulto , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , China/epidemiologia , Genótipo , Humanos , Lactente , Masculino , Vacina contra Sarampo/administração & dosagem , Pessoa de Meia-Idade , Mianmar/epidemiologia , RNA Viral/isolamento & purificação , Adulto Jovem
9.
Arthritis Rheum ; 50(9): 2750-6, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15457442

RESUMO

OBJECTIVE: To examine the roles of specific genetic polymorphisms as predictors of response to treatment of early rheumatoid arthritis (RA). METHODS: Subjects included 457 patients with early RA (duration of < or =3 years) who participated in a randomized controlled trial comparing weekly methotrexate and 2 dosages of etanercept (10 mg twice weekly and 25 mg twice weekly). Our primary outcome measure was achievement of 50% improvement in disease activity according to the criteria of the American College of Rheumatology (ACR50 response) after 12 months of treatment. Subjects were genotyped for HLA-DRB1 alleles and polymorphisms in the following genes: TNF, LTA, TNFRSF1A, TNFRSF1B, FCGR2A, FCGR3A, and FCGR3B. Univariate and multivariate analyses were performed to define the impact of specific polymorphisms and haplotypes on response to treatment. Covariates for the multivariate analyses included sex, ethnicity, age, disease duration, and baseline values for rheumatoid factor and the tender and swollen joint counts. RESULTS: The presence of 2 HLA-DRB1 alleles encoding the shared epitope (SE) (compared with 1 or 0 copies) was associated with response to treatment with standard-dose etanercept (odds ratio [OR] 4.3, 95% confidence interval [95% CI] 1.8-10.3). Among Caucasian patients, 2 extended haplotypes that included the HLA-DRB1 alleles *0404 and *0101 (both of which encode the SE) and 6 single-nucleotide polymorphisms in the LTA-TNF region were associated with response to treatment. In a multivariate model that included treatment received and the aforementioned covariates, the ORs for the association of these haplotypes with achievement of an ACR50 response at 12 months were 2.5 (95% CI 0.8-7.3) and 4.9 (95% CI 1.5-16.1) for the *0404- and *0101-containing haplotypes, respectively. CONCLUSION: Genetic variation in the HLA-DRB1 and the LTA-TNF regions is significantly associated with response to treatment of early RA. These findings may have clinical application through the identification of patients who are most likely to benefit from treatment with methotrexate or etanercept.


Assuntos
Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/genética , Antígenos HLA-DR/genética , Linfotoxina-alfa/genética , Fator de Necrose Tumoral alfa/genética , Antirreumáticos/uso terapêutico , Etanercepte , Feminino , Predisposição Genética para Doença , Cadeias HLA-DRB1 , Humanos , Imunoglobulina G/uso terapêutico , Masculino , Metotrexato/uso terapêutico , Pessoa de Meia-Idade , Polimorfismo Genético , Receptores do Fator de Necrose Tumoral/uso terapêutico , Índice de Gravidade de Doença , Resultado do Tratamento
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