筛选条件 共查询到40条结果
排序方式
Effects of Fuel Type and Spraying Parameters on Microstructure and Mechanical Properties of HVOF Sprayed WC10Co4Cr Coatings

期刊: CHINA SURFACE ENGINEERING, 2019; 32 (5)

HVOF sprayed WC-based cermet coatings have been widely used in industries for wear, corrosion and cavitation protection of the metallic components. WC10Co4Cr coatings were deposited by gas fuel-HVOF (GF-HVOF) and liquid fuel-HVOF (LF-HVOF) processes at 9 different spraying conditions to investigate the effect of fuel type on microstructure, residual stress and mechanical properties of HVOF cermet coatings. For the coatings prepared at optimized conditions, residual stress raised in the coatings was in-situ monitored by testing the curvature evolution of the substrate during spraying. Vickers microhardness, indentation and ball-on-disc wear test were performed to evaluate mechanical properties of the resultant cermet coatings. The results show that cermet particles have higher velocity and lower surface temperature in LF-HVOF than those in GF-HVOF. A compressive residual stress is formed in the LF-HVOF WC10Co4Cr coating while a residual stress is detected in the GF-HVOF coating. Because of combination of more compact microstructure and compressive residual stress, the LFHVOF cermet coating (1280 HV0.3, 7.3 MPa.m(0.5)) shows both higher hardness and higher fracture toughness and thereby higher wear resistance than that of CF-HVOF coating (1032 HV0.3, 4.5 MPa.m(0.)(5)).

Isolation of Single Intracellular Bacterial Communities Generated from a Murine Model of Urinary Tract Infection for Downstream Single-cell Analysis

期刊: JOVE-JOURNAL OF VISUALIZED EXPERIMENTS, 2019; (146)

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected in the urinary tract. The protocol can be broadly divided into three sections: the infection, bladder epithelial cell harvesting, and mouth micropipetting to isolate individual infected epithelial cells. The isolated epithelial cell contains viable bacterial cells and is nearly free of contaminating extracellular bacteria, making it ideal for downstream single-cell analysis. The time taken from the start of infection to obtaining a single intracellular bacterial community is about 8 h. This protocol is inexpensive to deploy and uses widely available materials, and we anticipate that it can also be utilized in other infection models to isolate single infected cells from cell mixtures even if those infected cells are rare. However, due to a potential risk in mouth micropipetting, this procedure is not recommended for highly infectious agents.

IF:1.11

NCP activates chloroplast transcription by controlling phytochrome-dependent dual nuclear and plastidial switches

期刊: NATURE COMMUNICATIONS, 2019; 10 ()

Phytochromes initiate chloroplast biogenesis by activating genes encoding the photosynthetic apparatus, including photosynthesis-associated plastid-encoded genes (PhAPGs). PhAPGs are transcribed by a bacterial-type RNA polymerase (PEP), but how phytochromes in the nucleus activate chloroplast gene expression remains enigmatic. We report here a forward genetic screen in Arabidopsis that identified NUCLEAR CONTROL OF PEP ACTIVITY (NCP) as a necessary component of phytochrome signaling for PhAPG activation. NCP is dual-targeted to plastids and the nucleus. While nuclear NCP mediates the degradation of two repressors of chloroplast biogenesis, PIF1 and PIF3, NCP in plastids promotes the assembly of the PEP complex for PhAPG transcription. NCP and its paralog RCB are non-catalytic thioredoxin-like proteins that diverged in seed plants to adopt nonredundant functions in phytochrome signaling. These results support a model in which phytochromes control PhAPG expression through light-dependent double nuclear and plastidial switches that are linked by evolutionarily conserved and dual-localized regulatory proteins.

IF:11.88

Bioactive: A new era of bioactive ingredients in topical formulations for inflammatory dermatoses

期刊: DERMATOLOGIC THERAPY, 0; ()

Moisturization is the pillar of daily skin care and has significant benefit in improving hydration, strengthening the skin barrier, and ameliorating inflammatory dermatoses. Bioactive ingredients such as endocannabinoids, bioactive lipids, growth factors, microbiome modulators, and antioxidant enzymes are increasingly being incorporated into moisturizer formulations. These novel ingredients have been shown to improve skin barrier function, upregulate barrier lipid synthesis, decrease itch and inflammation, and have antioxidative properties. In this article, we highlight evidence supporting their mechanisms of action and efficacy in atopic dermatitis, uremic pruritus, asteatotic eczema, acne vulgaris, and vitiligo.

Human-Water Infrastructure Interactions: Substituting Services Received for Bottled and Filtered Water in US Shrinking Cities

期刊: JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT, 2019; 145 (12)

Aging infrastructure has caused municipalities to experience an increasing number of water-related challenges, such as noncompliance with water-quality standards or failing infrastructure. Consequentially, with heightened levels of public concern toward drinking water, residents might opt to use bottled or filtered water over tap water. Shrinking cities characteristically have underutilized systems due to chronic urban decline occurring over multiple decades without a corresponding reduction in the infrastructure footprint. Substituting products and using point-of-use filtration systems further exacerbates this problem of decreased demand, and the associated costs may be burdensome to low-income residents, who often comprise upward of 40% of shrinking-city residents. An online survey was deployed in June 2016 to 21 US shrinking cities. A mixed-method approach sought to assess public attitudes toward water received at the tap and to understand the public behavior of using bottled and filtered water in US shrinking cities. Statistical analyses revealed parameters influencing the likelihood of using bottled and filtered water. Qualitative analyses provided insight into how these substitute behaviors are occurring in the household. (c) 2019 American Society of Civil Engineers.

IF:3.4

Dynamic Public Perceptions of Water Infrastructure in US Shrinking Cities: End-User Trust in Providers and Views toward Participatory Processes

期刊: JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT, 2019; 145 (9)

The operating environment of water infrastructure is inherently dynamic due to factors such as water-related events, media coverage of such events, or changes in institutional expectations. This dynamic environment impacts public perceptions of infrastructure services and providers. In an effort to understand public views regarding water infrastructure, decision makers may periodically assess perceptions to aid in pursuing successful community-supported management strategies. However, single cross-sectional samples from previous studies do not consider the changes in perceptions over time. This study assessed dynamic perceptions of local water providers using two surveys deployed in 21 US shrinking cities, before (2013) and after (2016) media attention on nationwide water infrastructure challenges arising from events such as the Flint water crisis. Questions of interest pertained to whether respondents trust their water providers and want to partake in participatory processes of local utilities. Results indicated a statistically significant change in perceptions, highlighting the importance of temporal sampling. Statistical modeling revealed that geographic parameters typically have homogeneous impacts, indicating localized factors influencing utility-customer relationships in shaping perceptions, whereas demographic parameters have heterogeneous impacts. (c) 2019 American Society of Civil Engineers.

IF:3.4

Trophic interactions of micro- and mesozooplankton in the Amundsen Sea polynya and adjacent sea ice zone during austral late summer

期刊: PROGRESS IN OCEANOGRAPHY, 2019; 174 ()

To elucidate the trophic link between micro- and mesozooplankton in the Amundsen Sea polynya (ASP) and adjacent sea ice zone, we estimated the impact of microzooplankton grazing on major phytoplankton groups, as well as the diet composition, ingestion rate, and prey selectivity of two copepods and Euphausia crystallorophias larvae on microbial communities during the late summer. Phaeocystis antarctica, which was ingested by micro-and mesozooplankton, comprised most phytoplankton biomass. Herbivorous microzooplankton consumed at least half of the phytoplankton production, but the microzooplankton grazing may not contribute strongly to the decline of the phytoplankton bloom. Three mesozooplankton species (Calanoides acutus, Metridia gerlachei, and E. crystallorophias larvae) preferentially grazed on ciliates and heterotrophic dinoflagellates (HDF) with sizes from 20 to > 100 mu m over phytoplankton. Although microzooplankton comprised only an average of 41.7 +/- 3.2% of the total carbon available in the natural prey pool, they accounted for an average of 75.4 +/- 2.9% of total carbon ingested by copepods and krill larvae. Heterotrophic food sources made up a substantial proportion of mesozooplankton diets, with strong positive selection for microzooplankton at most locations regardless of phytoplankton size and type. In particular, HDF comprised the major dietary component of mesozooplankton in the study area. The presence of mesozooplankton reduced the grazing pressure on P. antarctica and diatoms through predation on herbivorous microzooplankton. Approximately half of the primary production capacity may have indirectly reached mesozooplankton through microzooplankton consumption. Thus, strongly selective feeding behavior and higher grazing pressure on microzooplankton indicated the importance of microheterotrophic pathways through strong trophic coupling between mesozooplankton and the microbial food web during the decline of phytoplankton bloom. In the highly productive ASP system, food web structure can be classified as multivorous, whereby herbivorous and omnivorous modes both play significant roles in carbon export, enhancing the efficiency of the pelagic food web.

IF:3.24

beta-Secretase inhibition by C-methylisoflavones from Abronia nana

期刊: NATURAL PRODUCT RESEARCH, 2019; 33 (12)

The methanol extract of Abronia nana suspension cultures were subjected to column chromatography to identify potential inhibitors of beta-secretase, which is a major factor in Alzheimer's disease development. Two new C-methylisoflavones boeravinone T (1) and U (4) were isolated with three knowns boeravinone B (2), J (3) and X (5). The half-maximal inhibitory concentration (IC50) values of compounds 1-5 were 18.29, 8.57, 7.87, 12.02 and 5.30 mu M, respectively. The most potent 5, non-competitively inhibited beta-secretase [inhibition constant (K-i) = 3.79 mu M]. Compounds 1-5 did not inhibit other proteases such as chymotrypsin, trypsin and elastase at concentrations up to 1 mM, indicating that they were relatively specific inhibitors of beta-secretase. A free hydroxyl group at C-3 position of the C-methylisoflavone skeleton appeared to be responsible for the stronger inhibitory activity against beta-secretase. [GRAPHICS] .

IF:2.0

Evaluating guselkumab: an anti-IL-23 antibody for the treatment of plaque psoriasis

期刊: DRUG DESIGN DEVELOPMENT AND THERAPY, 2019; 13 ()

The approval of guselkumab marks the entry of the IL-23 inhibitor class into the therapeutic armamentarium for patients with moderate-to-severe plaque psoriasis. This class specifically targets the upstream portion of the type 17 helper T (Th17) axis, which has been implicated as a key driver of the abnormal inflammatory state observed in psoriasis. Guselkumab is highly efficacious, with over 85% of the patients achieving >= 75% reduction in Psoriasis Area and Severity Index from baseline (PASI 75) and over 70% of the patients achieving PASI 90 response in its Phase III clinical trials. Additionally, this medication is well-tolerated, with non-serious infections such as nasopharyngitis and upper respiratory infections (URIs) being the most common adverse events (AEs) reported in its clinical trials. Guselkumab offers yet another effective treatment option in the rapidly growing list of available biological therapies for moderate-to-severe plaque psoriasis.

IF:3.21

Ethanol extract of Glycyrrhizae Radix modulates the responses of antigen-specific splenocytes in experimental autoimmune encephalomyelitis

期刊: PHYTOMEDICINE, 2019; 54 ()

Background: Multiple sclerosis (MS) is an autoimmune disorder resulting in paralysis, and the responses of reactive T cells against self-antigens are hallmarks. Glycyrrhizae Radix (GR) has been used for detoxification and reducing inflammation. However, very few reports have described the effects of GR on MS. Purpose: The immunomodulatory effects of GR extract on autoimmune responses were evaluated through in vitro, ex vivo, and in vivo assays using primary mouse splenocytes (SPLC), mouse microglia BV2 cell line, and a mouse model of experimental autoimmune encephalomyelitis (EAE). Study design: Ethanol extract of GR was used in vitro with primary SPLC in the condition of anti-CD3/CD28 stimulation and interferon (IFN)-gamma-producing CD4 + (TH1)/CD8 + (TC1) polarization as well as IFN-gamma-stimulated BV2 cells. For EAE induction, female C57BL/6 mice were immunized with 200 mu g of myelin oligodendrocyte glycoprotein (MOG)35-55 without pertussis toxin. EAE SPLC (ex vivo) and EAE mice (in vivo) were treated with GR extract to evaluate the changes in antigen-specific responses. SPLC media containing antigen-specific responses were used to stimulate BV2 cells. Results: GR extract effectively modulated the responses of reactive splenic T cells through the reduction in IFN-gamma + T cell populations, the expressions of cell adhesion molecules (CAMs), and secretions of cytokines containing IFN-gamma and a chemokine IFN-gamma-induced protein 10 (IP-10) in vitro. In addition, GR extract significantly decreased nitric oxide production and secretion of tumor necrosis factor (TNF)-alpha and IP-10 in IFN-gamma-stimulated BV2 cells. The antigen-specific TH1 and TC1 populations were decreased following administration of 100 mg/kg of GR extract, whereas CD8 + IL-17A + (TC17) population was increased on day 36 after EAE induction. Moreover, IFN-gamma, which showed the highest secretion among examined cytokines, and IP-10 decreased on day 36. SPLC media derived from 100 mg/kg GR extract-administered EAE mice revealed the ameliorative effects on BV2 cell stimulation. Conclusion: This is the first report on the immunomodulatory effects of GR extract on antigen-specific SPLC responses in EAE. These results could be helpful for the discovery of drug candidates for MS by focusing on IFN-gamma-related autoimmune responses.

IF:4.18

The impact of pediatric atopic dermatitis on families: A review

期刊: PEDIATRIC DERMATOLOGY, 2019; 36 (1)

Background Atopic dermatitis (AD) is an extremely common childhood disease, with considerable impact on the quality of life of affected children and their families. While pruritus is the hallmark symptom of this disease, AD has been well-documented to impact patients beyond physical symptoms, resulting in behavior problems, mood disorders, and sleep disturbance. Objective This literature review outlines how atopic dermatitis impacts the quality of life of families of children affected by AD. Methods A total of 3436 articles were identified via an online search of the MEDLINE health literature database and were screened for relevance to quality of life impacts on families with children affected by AD. Results Caring for children affected by AD can be an extremely time-consuming task that can impair personal relationships, decrease psychosocial functioning, and cause sleep loss among family members of affected patients. Additionally, AD may result in work absence or decreased work productivity for caregivers. Special diets, irritant and allergen avoidance strategies, and alternative therapies are commonly used by patients to manage their disease and require large amounts of family involvement. Conclusions Atopic dermatitis can greatly decrease quality of life of families of affected children in various domains, including sleep, finances, and relationships. Early intervention and psychotherapy may be needed in some patients to address these quality of life impairments.

IF:1.18

共40条页码: 1/3页15条/页