Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Más filtros













Base de datos
Intervalo de año de publicación
1.
Langmuir ; 40(19): 9892-9910, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38685830

RESUMEN

Nowadays, high-phase-inversion in situ emulsification technology has shown great potential in enhancing oil recovery from high-water-cut thin-oil reservoirs. However, emulsification characteristics, interfacial properties, and the mechanism of high phase inversion have not been systematically described. In this study, an emulsification experiment was conducted to investigate the effects of shear time, shear rate, and temperature on the phase inversion of thin oil. Furthermore, the influence of resin and wax on the dispersion of asphaltene was studied through microscopic morphology analysis. Interfacial tension measurement and interfacial viscoelasticity analysis were carried out to determine the interaction characteristics of asphaltene, resin, and wax at the interface. The results showed that, at 50 °C, the phase-inversion point of thin oil reached as high as 75%, and even at 60 °C, it remained at 70%. The shear time and shear rate did not affect the phase-inversion point of thin oil, while an increase in temperature led to a decrease in the phase-inversion point. Moreover, compared to the 20% phase-inversion point of base oil, the phase-inversion point increased with different proportions of asphaltene, resin, and wax. Particularly, at the ratio of asphaltene/resin/wax = 1:5:9, the phase-inversion point reached as high as 80%, indicating the optimal state. In this proportion, asphaltene aggregates exhibited the smallest and most uniform size, best dispersion, lower interfacial tension, and higher interfacial modulus. These findings provide reference and guidance for further enhancing oil recovery in medium-to-high-water-cut thin-oil reservoirs.

2.
mBio ; : e0234623, 2023 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-37874152

RESUMEN

Cerebral malaria (CM) is a severe neurological complication of Plasmodium falciparum infection with acute brain lesions. Genetic variations in both host and parasite have been associated with susceptibility to CM, but the underlying molecular mechanism remains unclear. Here, we demonstrate that variants of human apolipoprotein E (hApoE) impact the outcome of Plasmodium berghei ANKA (PbA)-induced experimental cerebral malaria (ECM). Mice carrying the hApoE2 isoform have fewer intracerebral hemorrhages and are more resistant to ECM than mice bearing the hApoE3, hApoE4, or endogenous murine ApoE (mApoE). hApoE2 mice infected with PbA showed increased splenomegaly and IFN-γ levels in serum but reduced cerebral cell apoptosis that correlated with the survival advantage against ECM. In addition, upregulated expression of genes associated with lipid metabolism and downregulated expression of genes linked to immune responses were observed in the brain tissue of hApoE2 mice relative to ECM-susceptible mice after PbA infection. Notably, serum cholesterol and the cholesterol content of brain-infiltrating CD8+ T cells are significantly higher in infected hApoE2 mice, which might contribute to a significant reduction in the sequestration of brain CD8+ T cells. Consistent with the finding that fewer brain lesions occurred in infected hApoE2 mice, fewer behavioral deficits were observed in the hApoE2 mice. Finally, a meta-analysis of publicly available data also showed an increased hApoE2 allele in the malaria-endemic African population, suggesting malaria selection. This study shows that hApoE2 protects mice from ECM through suppression of CD8+ T cell activation and migration to the brain and enhanced cholesterol metabolism.IMPORTANCECerebral malaria (CM) is the deadliest complication of malaria infection with an estimated 15%-25% mortality. Even with timely and effective treatment with antimalarial drugs such as quinine and artemisinin derivatives, survivors of CM may suffer long-term cognitive and neurological impairment. Here, we show that human apolipoprotein E variant 2 (hApoE2) protects mice from experimental CM (ECM) via suppression of CD8+ T cell activation and infiltration to the brain, enhanced cholesterol metabolism, and increased IFN-γ production, leading to reduced endothelial cell apoptosis, BBB disruption, and ECM symptoms. Our results suggest that hApoE can be an important factor for risk assessment and treatment of CM in humans.

3.
J Chem Phys ; 158(11): 114103, 2023 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-36948793

RESUMEN

Neural network potentials (NNPs) can greatly accelerate atomistic simulations relative to ab initio methods, allowing one to sample a broader range of structural outcomes and transformation pathways. In this work, we demonstrate an active sampling algorithm that trains an NNP that is able to produce microstructural evolutions with accuracy comparable to those obtained by density functional theory, exemplified during structure optimizations for a model Cu-Ni multilayer system. We then use the NNP, in conjunction with a perturbation scheme, to stochastically sample structural and energetic changes caused by shear-induced deformation, demonstrating the range of possible intermixing and vacancy migration pathways that can be obtained as a result of the speedups provided by the NNP. The code to implement our active learning strategy and NNP-driven stochastic shear simulations is openly available at https://github.com/pnnl/Active-Sampling-for-Atomistic-Potentials.

4.
Ann Fam Med ; 21(1): 33-39, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36635084

RESUMEN

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic facilitated the rapid development of digital detection surveillance (DDS) for outbreaks. This qualitative study examined how DDS for infectious diseases (ID) was perceived and experienced by primary care physicians and patients in order to highlight ethical considerations for promoting patients' autonomy and health care rights. METHODS: In-depth interviews were conducted with a purposefully selected group of 16 primary care physicians and 24 of their patients. The group was reflective of a range of ages, educational attainment, and clinical experiences from urban areas in northern and southern China. Interviews were audio recorded, transcribed, and translated. Two researchers coded data and organized it into themes. A third researcher reviewed 15% of the data and discussed findings with the other researchers to assure accuracy. RESULTS: Five themes were identified: ambiguity around the need for informed consent with usage of DDS; importance of autonomous decision making; potential for discrimination against vulnerable users of DDS for ID; risk of social inequity and disparate care outcomes; and authoritarian institutions' responsibility for maintaining health data security. The adoption of DDS meant some patients would be reluctant to go to the hospital for fear of either being discriminated against or forced into quarantine. Certain groups (older people and children) were thought to be vulnerable to DDS misappropriation. CONCLUSIONS: These findings indicate the paramount importance of establishing national and international ethical frameworks for DDS implementation. Frameworks should guide all aspects of ID surveillance, addressing privacy protection and health security, and underscored by principles of social equity and accountability.Annals "Online First" article.


Asunto(s)
COVID-19 , Enfermedades Transmisibles , Médicos de Atención Primaria , Niño , Humanos , Anciano , Consentimiento Informado , Investigación Cualitativa
5.
ACS Omega ; 7(16): 13721-13736, 2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35559162

RESUMEN

Deformation processing of immiscible systems is observed to disrupt thermodynamic equilibrium, often resulting in nonequilibrium microstructures. The microstructural changes including nanostructuring, hierarchical distribution of phases, localized solute supersaturation, and oxygen ingress result from high-strain extended deformation, causing a significant change in mechanical properties. Because of the dynamic evolution of the material under large strain shear load, a detailed understanding of the transformation pathway has not been established. Additionally, the influence of these microstructural changes on mechanical properties is also not well characterized. Here, an immiscible Cu-4 at. % Nb alloy is subjected to a high-strain shear deformation (∼200); the deformation-induced changes in the morphology, crystal structure, and composition of Cu and Nb phases as a function of total strain are characterized using transmission electron microscopy and atom probe tomography. Furthermore, a multimodal experiment-guided computational approach is used to depict the initiation of deformation by an increase in misorientation boundaries by crystal plasticity-based grain misorientation modeling (strain ∼0.6). Then, co-deformation and nanolamination of Cu and Nb are envisaged by a finite element method-based computational fluid dynamic model with strain ranging from 10 to 200. Finally, the experimentally observed amorphization of the severely sheared supersaturated Cu-Nb-O phase was validated using the first principle-based simulation using density functional theory while highlighting the influence of oxygen ingress during deformation. Furthermore, the nanocrystalline microstructure shows a >2-fold increase in hardness and compressive yield strength of the alloy, elucidating the potential of deformation processing to obtain high-strength low-alloyed metals. Our approach presents a step-by-step evolution of a microstructure in an immiscible alloy undergoing severe shear deformation, which is broadly applicable to materials processing based on friction stir, extrusion, rolling, and surface shear deformation under wear and can be directly applied to understanding material behavior during these processes.

6.
J Med Internet Res ; 23(10): e32328, 2021 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-34543228

RESUMEN

BACKGROUND: The COVID-19 pandemic has increased the importance of the deployment of digital detection surveillance systems to support early warning and monitoring of infectious diseases. These opportunities create a "double-edge sword," as the ethical governance of such approaches often lags behind technological achievements. OBJECTIVE: The aim was to investigate ethical issues identified from utilizing artificial intelligence-augmented surveillance or early warning systems to monitor and detect common or novel infectious disease outbreaks. METHODS: In a number of databases, we searched relevant articles that addressed ethical issues of using artificial intelligence, digital surveillance systems, early warning systems, and/or big data analytics technology for detecting, monitoring, or tracing infectious diseases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and further identified and analyzed them with a theoretical framework. RESULTS: This systematic review identified 29 articles presented in 6 major themes clustered under individual, organizational, and societal levels, including awareness of implementing digital surveillance, digital integrity, trust, privacy and confidentiality, civil rights, and governance. While these measures were understandable during a pandemic, the public had concerns about receiving inadequate information; unclear governance frameworks; and lack of privacy protection, data integrity, and autonomy when utilizing infectious disease digital surveillance. The barriers to engagement could widen existing health care disparities or digital divides by underrepresenting vulnerable and at-risk populations, and patients' highly sensitive data, such as their movements and contacts, could be exposed to outside sources, impinging significantly upon basic human and civil rights. CONCLUSIONS: Our findings inform ethical considerations for service delivery models for medical practitioners and policymakers involved in the use of digital surveillance for infectious disease spread, and provide a basis for a global governance structure. TRIAL REGISTRATION: PROSPERO CRD42021259180; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=259180.


Asunto(s)
COVID-19 , Enfermedades Transmisibles , Inteligencia Artificial , Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/epidemiología , Humanos , Pandemias , SARS-CoV-2
7.
J Biosci ; 452020.
Artículo en Inglés | MEDLINE | ID: mdl-32515360

RESUMEN

Endometriosis is a common disease in women, which impairs the quality of life in patients. Recently, accumulating evidences reported that miRNAs play an essential role in diagnosis and treatment of endometriosis. However, the regulatory mechanism of miRNAs has not been fully explored. The expression of miR-17-5p and VEGFA was detected using qRT-PCR. The protein level of VEGFA was measured via Western blot. Cell proliferation was determined by CCK-8 assay. Cell migration and invasion were measured via transwell assay. The relationship of miR-17-5p and VEGFA were verified via luciferase reporter assay. Then miR-17-5p was remarkably down-regulated in endometriosis tissues, serums and cells, and overexpression of miR-17-5p inhibited cell proliferation, migration and invasion in endometriosis. Results showed that VEGFA was significantly up-regulated in endometriosis tissues and cells and acted as a target of miR-17-5p. Moreover, miR- 17-5p negatively regulated VEGFA expression in endometriosis. Otherwise, up-regulation of VEGFA improved cell proliferative, migrated and invasive ability in ECSCs with transfection of miR-17-5p mimics group. Our data showed miR-17-5p inhibits cell proliferation, migration and invasion in endometriosis by directly repressing VEGFA expression.


Asunto(s)
Endometriosis/diagnóstico , Endometriosis/metabolismo , MicroARNs/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Movimiento Celular , Células Cultivadas , Femenino , Regulación de la Expresión Génica , Humanos , MicroARNs/genética , Células del Estroma/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética
8.
PLoS One ; 11(8): e0161869, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27571513

RESUMEN

Leucocytozoon parasites infect many species of avian hosts, including domestic chicken, and can inflict heavy economic loss on the poultry industry. Two major species of Leucocytozoon parasites have been reported in China, L. sabrazesi and L. caulleryi, although L. sabrazesi appears to be more widespread than L. caulleryi in southern China. The traditional method for detecting Leucocytozoon infection is microscopic examination of blood smears for the presence of mature gametocytes in circulation, which may miss infections with low parasitemia (gametocytemia) or immature gametocytes. Here we developed a PCR-based method to monitor L. sabrazesi infections at seven sites in four provinces of China after testing two PCR primer pairs based on parasite mitochondrial cytochrome b (cytb) and cytochrome c oxidase III (coxIII) genes. We compared the results of PCR detection with those of microscopic observation. As expected, the PCR assays were more sensitive than microscope examination in detecting L. sabrazesi infection and were able to detect parasite DNA after gametocytes disappeared in the blood stream. Using these methods, we investigated monthly dynamics of L. sabrazesi in chickens from a free-range farm in Xiamen, Fujian province of China, over one year. Our results showed that chickens were infected with L. sabrazesi year-round in southern China. Finally, we tested several compounds for potential treatment of Leucocytozoon infections, including primaquine, ketotifen, clomipramine hydrochloride, desipramine hydrochloride, sulfaquinoxaline, and pyrimethamine. Only primaquine had activity against L. sabrazesi gametocytes. Our results provide important information for controlling parasite transmission in southern China and disease management.


Asunto(s)
Haemosporida/patogenicidad , Parasitemia/parasitología , Enfermedades de las Aves de Corral/parasitología , Animales , Pollos/parasitología , China , ADN Protozoario/genética , Femenino , Haemosporida/genética , Parasitemia/epidemiología , Reacción en Cadena de la Polimerasa , Enfermedades de las Aves de Corral/epidemiología , Infecciones Protozoarias en Animales/epidemiología , Infecciones Protozoarias en Animales/parasitología
9.
Malar J ; 15: 30, 2016 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-26791272

RESUMEN

BACKGROUND: The rodent malaria parasite Plasmodium yoelii is an important animal model for studying host-parasite interaction and molecular basis of malaria pathogenesis. Although a draft genome of P. yoelii yoelii YM is available, and RNA sequencing (RNA-seq) data for several rodent malaria species (RMP) were reported recently, variations in coding regions and structure of mRNA transcript are likely present between different parasite strains or subspecies. Sequencing of cDNA libraries from additional parasite strains/subspecies will help improve the gene models and genome annotation. METHODS: Here two directional cDNA libraries from mixed blood stages of a subspecies of P. yoelii (P. y. nigeriensis NSM) with or without mefloquine (MQ) treatment were sequenced, and the sequence reads were compared to the genome and cDNA sequences of P. y. yoelii YM in public databases to investigate single nucleotide polymorphisms (SNPs) in coding regions, variations in intron-exon structure and differential splicing between P. yoelii subspecies, and variations in gene expression under MQ pressure. RESULTS: Approximately 56 million of 100 bp paired-end reads were obtained, providing an average of ~225-fold coverage for the coding regions. Comparison of the sequence reads to the YM genome revealed introns in 5' and 3' untranslated regions (UTRs), altered intron/exon boundaries, alternative splicing, overlapping sense-antisense reads, and potentially new transcripts. Interestingly, comparison of the NSM RNA-seq reads obtained here with those of YM discovered differentially spliced introns; e.g., spliced introns in one subspecies but not the other. Alignment of the NSM cDNA sequences to the YM genome sequence also identified ~84,000 SNPs between the two parasites. CONCLUSION: The discoveries of UTR introns and differentially spliced introns between P. yoelii subspecies raise interesting questions on the potential role of these introns in regulating gene expression and evolution of malaria parasites.


Asunto(s)
Empalme Alternativo/genética , Intrones/genética , Plasmodium yoelii/genética , ARN sin Sentido/genética , Genoma de Protozoos/genética , Malaria/parasitología , Polimorfismo de Nucleótido Simple/genética
10.
PLoS One ; 10(7): e0133478, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26218846

RESUMEN

Leucocytozoon parasites infect a large number of avian hosts, including domestic chicken, and cause significant economical loss to the poultry industry. Although the transmission stages of the parasites were observed in avian blood cells more than a century ago, the specific host cell type(s) that the gametocytes infect remain uncertain. Because all the avian blood cells, including red blood cells (RBCs), are nucleated, and the developing parasites dramatically change the morphology of the infected host cells, it has been difficult to identify Leucocytozoon infected host cell(s). Here we use cell-type specific antibodies to investigate the identities of the host cells infected by Leucocytozoon sabrazesi gametocytes. Anti-RBC antibodies stained RBCs membrane strongly, but not the parasite-infected cells, ruling out the possibility of RBCs being the infected host cells. Antibodies recognizing various leukocytes including heterophils, monocytes, lymphocytes, and macrophages did not stain the infected cells either. Antisera raised against a peptide of the parasite cytochrome B (CYTB) stained parasite-infected cells and some leukocytes, particularly cells with a single round nucleus as well as clear/pale cytoplasm suggestive of thrombocytes. Finally, a monoclonal antibody known to specifically bind chicken thrombocytes also stained the infected cells, confirming that L. sabrazesi gametocytes develop within chicken thrombocytes. The identification of L. sabrazesi infected host cell solves a long unresolved puzzle and provides important information for studying parasite invasion of host cells and for developing reagents to interrupt parasite transmission.


Asunto(s)
Plaquetas/parasitología , Haemosporida/patogenicidad , Animales , Anticuerpos Antiprotozoarios/inmunología , Células Sanguíneas/parasitología , Pollos/parasitología , Femenino , Células Germinativas , Haemosporida/inmunología , Interacciones Huésped-Parásitos , Integrina alfaV/inmunología , Integrina beta3/inmunología , Masculino , Infecciones por Protozoos/sangre , Infecciones por Protozoos/parasitología
11.
J Hum Genet ; 59(8): 475-6, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25007882

RESUMEN

Severe acne presents sexual dimorphism in its incidence in Chinese population. It is more prevalent in males. To assess the possible Y chromosomal contribution to severe acne risk in Han Chinese males, we analyzed 2041 Y chromosomal SNPs (Y-SNPs) in 725 severe acne cases and 651 controls retrieved from our recent genome-wide association study data. After data filtering, we assigned 585 cases and 494 controls into 12 Y chromosomal haplogroups based on 307 high-confidence Y-SNPs. No statistically significant difference in the distribution of Y chromosomal haplogroup frequencies was observed between the case and control groups. Our results showed a lack of association between the incidence of severe acne and the different Y chromosomal haplogroup in the Han Chinese population.


Asunto(s)
Acné Vulgar/genética , Pueblo Asiatico/genética , Cromosomas Humanos Y/genética , Polimorfismo de Nucleótido Simple/genética , Acné Vulgar/epidemiología , Estudio de Asociación del Genoma Completo , Haplotipos , Humanos , Masculino
12.
Phys Chem Chem Phys ; 16(12): 5553-62, 2014 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-24513975

RESUMEN

The initial dissociative adsorption step of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) molecule on the surfaces of MgO, CaO, and CuO has been studied by density functional theory (DFT) using periodic slab models. It is found that the 2,3,7,8-TCDD molecule undergoes a similar dissociative adsorption step during the decomposition over the three metal oxide surfaces. The adsorption configuration of 2,3,7,8-TCDD first converts from a parallel mode into a vertical one, then a nucleophilic substitution process takes place, where the surface oxygen atom attacks the aromatic carbon to form a surface phenolate with the chlorine atom moving to the top of the nearest surface metal atom. The calculated apparent activation energy of the dissociation increases in the order of CuO < CaO < MgO. The reaction heat is -0.67 eV, -0.75 eV, and 0.45 eV for CuO, CaO, and MgO, respectively, suggesting the thermodynamic tendency of MgO < CuO < CaO, which parallels the trend of the nucleophilicity of surface oxygen atoms. This study suggests that metal oxides with more nucleophilic and less tightly-bonded surface oxygen atoms might be more promising for the decomposition of polychlorinated dibenzo-p-dioxins and dibenzofurans.


Asunto(s)
Monóxido de Carbono/química , Cerio/química , Óxido de Magnesio/química , Dibenzodioxinas Policloradas/química , Teoría Cuántica , Adsorción , Propiedades de Superficie
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA