| 1. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
|
|
| 2. |
- Dai, Qingyuan, et al.
(författare)
-
Severe dioxin-like compound (DLC) contamination in e-waste recycling areas : An under-recognized threat to local health
- 2020
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 139
-
Tidskriftsartikel (refereegranskat)abstract
- Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.
|
|
| 3. |
- Doherty, Brett T, et al.
(författare)
-
Maternal, cord, and three-year-old child serum thyroid hormone concentrations in the Health Outcomes and Measures of the Environment study
- 2020
-
Ingår i: Clinical Endocrinology. - : Blackwell Science Ltd.. - 0300-0664 .- 1365-2265. ; 92:4, s. 366-372
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Maternal thyroid function during pregnancy may influence offspring thyroid function, though relations between maternal and child thyroid function are incompletely understood. We sought to characterize relations between maternal, cord and child thyroid hormone concentrations in a population of mother-child pairs with largely normal thyroid function.METHODS: In a prospective birth cohort, we measured thyroid hormone concentrations in 203 mothers at 16 gestational weeks, 273 newborns and 159 children at 3 years among participants in the Health Outcomes and Measures of the Environment (HOME) Study. We used multivariable linear regression to estimate associations of maternal thyroid hormones during pregnancy with cord serum thyroid hormones and also estimated associations of maternal and cord thyroid hormones with child thyroid-stimulating hormone (TSH).RESULTS: Each doubling of maternal TSH was associated with a 16.4% increase of newborn TSH (95% CI: 3.9%, 30.5%), and each doubling of newborn TSH concentrations was associated with a 10.4% increase in child TSH concentrations at 3 years (95% CI: 0.1%, 21.7%). An interquartile range increase in cord FT4 concentrations was associated with an 11.7% decrease in child TSH concentrations at 3 years (95% CI: -20.2%, -2.3%).CONCLUSIONS: We observed relationships between maternal, newborn and child thyroid hormone concentrations in the HOME Study. Our study contributes to understandings of interindividual variability in thyroid function among mother-child pairs, which may inform future efforts to identify risk factors for thyroid disorders or thyroid-related health outcomes.
|
|
| 4. |
- Leung, Howell, et al.
(författare)
-
Risk assessment with gut microbiome and metabolite markers in NAFLD development
- 2022
-
Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 14:648, s. eabk0855-
-
Tidskriftsartikel (refereegranskat)abstract
- A growing body of evidence suggests interplay between the gut microbiota and the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the role of the gut microbiome in early detection of NAFLD is unclear. Prospective studies are necessary for identifying reliable, microbiome markers for early NAFLD. We evaluated 2487 individuals in a community-based cohort who were followed up 4.6 years after initial clinical examination and biospecimen sampling. Metagenomic and metabolomic characterizations using stool and serum samples taken at baseline were performed for 90 participants who progressed to NAFLD and 90 controls who remained NAFLD free at the follow-up visit. Cases and controls were matched for gender, age, body mass index (BMI) at baseline and follow-up, and 4-year BMI change. Machine learning models integrating baseline microbial signatures (14 features) correctly classified participants (auROCs of 0.72 to 0.80) based on their NAFLD status and liver fat accumulation at the 4-year follow up, outperforming other prognostic clinical models (auROCs of 0.58 to 0.60). We confirmed the biological relevance of the microbiome features by testing their diagnostic ability in four external NAFLD case-control cohorts examined by biopsy or magnetic resonance spectroscopy, from Asia, Europe, and the United States. Our findings raise the possibility of using gut microbiota for early clinical warning of NAFLD development.
|
|
| 5. |
- Wang, Xiaoyu, et al.
(författare)
-
A Novel Output-Constrained Controller for DC/DC Buck Converter Feeding Constant Power Loads in DC Microgrids
- 2023
-
Ingår i: IECON 2023 - 49th Annual Conference of the IEEE Industrial Electronics Society. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- DC microgrids have emerged as a promising solution for efficient and reliable electricity distribution. In DC microgrids, when power electronic loads and motor drives are tightly regulated, they behave as constant power loads (CPLs) and may lead to the instability issue. In this paper, a novel output-constrained controller for the DC/DC buck converter feeding CPLs is proposed. By introducing the output-constrained technique into the backstepping method, the proposed control scheme can keep the DC bus working within the pre-specific boundary even when large-signal disturbances happen. Relevant theoretical analyses are conducted by employing Laypunov stability theorem. Simulations in Matlab/Simulink are presented to verify the proposed controller.
|
|
| 6. |
- Xu, Aimin, 1953
(författare)
-
Structure of Hardened Cement-Fly Ash Systems and Their Related Properties
- 1992
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The influence of fly ash on the pore structure and microstructure of cement paste and mortar has been investigated. The methods applied include water vapour sorption isotherms, scanning electron microscopy, X-ray diffraction analysis and thermogravity/differential thermal analysis. The desorption isotherm test shows that, with low to medium cement replacement (F/(C+F) up to 0.30), fly ash does not significantly influence the pore structure as far as the ability to hold moisture is concerned. The same conclusion is applicable to the sorption isotherm, for which the specific surface area is a dominating factor. However, high volume fly ash addition results in a coarser pore structure, which leads to more moisture loss per paste at high relative humidity conditions, e.g. at 85% RH. Correspondingly, the sorption isotherm reveals a lower specific surface area value for the high volume fly ash mortar. The microstructural analysis shows that more calcium hydroxide per cement is produced in the paste with fly ash, which in turn reacts with fly ash to form calcium silicate hydrates and calcium aluminate hydrates similar to those produced by the cement hydration. However, the amount of calcium hydroxide per cement in the paste is lower only for the high volume fly ash specimens at late ages, i.e. later than 28 days. The analysis of the amount of cement at each age shows that the hydration of cement is approximately the same for the paste with and without fly ash. In conjunction with this, the hydration products in the paste with fly ash are usually a compound of calcium-aluminate-silicate with a low calcium oxide to silicon-alumina ratio. Since fly ash hydration is a slow process, the effect of calcium sulphate hydrate (as an activator) on the hydration of fly ash was studied. It has been shown that an appropriate addition of gypsum (CaSO4.2H2O) enhances the decomposition and reaction of fly ash. The reaction products include ettringite ({Ca6[Al(OH)6]2.24H2O}[(SO4)3.1.5H2O]), as well as calcium aluminate hydrate, e.g. C3AH6. It was observed that X-ray energy dispersive analysis of the ettringite-like phase reveals, more often than not, the inclusion of Si in the crystal lattice. The pore-filling effect of fly ash has been shown to be about the same as that of cement. However, this effect depends totally on the reactive phase of fly ash, which is about 50% for the fly ash studied in this work. The other factors influencing the pore structure, such as carbonation and ageing of the hydration products, were also tested. It is shown that the former results in coarser pore structure, and the latter affects some change in the C-S-H gel structure. In addition to the experimental work, the author has theoretically treated the effect of fly has, the desorption and adsorption isotherms, and the relation between shrinkage and the desorption isotherm.
|
|
