| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Cui, Peng, et al.
(författare)
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Long-term androgen excess induces insulin resistance and non-alcoholic fatty liver disease in PCOS-like rats.
- 2021
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Ingår i: The Journal of steroid biochemistry and molecular biology. - : Elsevier BV. - 1879-1220 .- 0960-0760. ; 208
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Tidskriftsartikel (refereegranskat)abstract
- Women with polycystic ovary syndrome (PCOS) are at higher risk for metabolic disorders compared to healthy women, and about 51 % of women with PCOS suffer from non-alcoholic fatty liver disease (NAFLD). Investigation into the pathological mechanism behind this association will provide insights for the prevention and treatment of this complication.Dihydrotestosterone (DHT), a nonaromatic androgen, was used to mimic the pathological conditions of hyperandrogenism and insulin resistance. Hematoxylin and eosin staining, Oil Red O staining, immunofluorescent staining, Western blots, and qRT-PCR were used to verify the hepatic steatosis and inflammation, and the latter two methods were also used for energy and mitochondrion-related assays. ELISA was used to measure the level of reactive oxygen species.Twelve weeks of DHT exposure led to obesity and insulin resistance as well as hepatic steatosis, lipid deposition, and different degrees of inflammation. The expression of molecules involved in respiratory chain and aerobic respiration processes, such as electron transfer complex II, pyruvate dehydrogenase, and succinate dehydrogenase complex subunit A, was inhibited. In addition, molecules associated with apoptosis and autophagy were also abnormally expressed, such as increased Bak mRNA, an increased activated caspase-3 to caspase-3 ratio, and increased Atg12 protein expression. All of these changes are associated with the mitochondria and lead to lipid deposition and inflammation in the liver.Long-term androgen excess contributes to insulin resistance and hepatic steatosis by affecting mitochondrial function and causing an imbalance in apoptosis and autophagy, thus suggesting the pathogenesis of NAFLD in women with PCOS.
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| 3. |
- Fang, Keyan, et al.
(författare)
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An interdecadal climate dipole between Northeast Asia and Antarctica over the past five centuries
- 2019
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 52:1/2, s. 765-775
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 Springer-Verlag GmbH Germany, part of Springer Nature Climate models emphasize the need to investigate inter-hemispheric climatic interactions. However, these models often underestimate the inter-hemispheric differences in climate change. With the wide application of reanalysis data since 1948, we identified a dipole pattern between the geopotential heights (GPHs) in Northeast Asia and Antarctica on the interdecadal scale in boreal summer. This Northeast Asia/Antarctica (NAA) dipole pattern is not conspicuous on the interannual scale, probably in that the interannual inter-hemispheric climate interaction is masked by strong interannual signals in the tropics associated with the El Niño-Southern Oscillation (ENSO). Unfortunately, the instrumental records are not sufficiently long-lasting to detect the interdecadal variability of the NAA. We thus reconstructed GPHs since 1565, making using the proxy records mostly from tree rings in Northeast Asia and ice cores from Antarctica. The strength of the NAA is time-varying and it is most conspicuous in the eighteenth century and after the late twentieth century. The strength of the NAA matches well with the variations of the solar radiation and tends to increase in along with its enhancement. In boreal summer, enhanced heating associated with high solar radiation in the Northern Hemisphere drives more air masses from the South to the North. This inter-hemispheric interaction is particularly strong in East Asia as a result of the Asian summer monsoon. Northeast Asia and Antarctica appear to be the key regions responsible for inter-hemispheric interactions on the interdecadal scale in boreal summer since they are respectively located at the front and the end of this inter-hemispheric trajectory.
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| 4. |
- Jiang, Peng, et al.
(författare)
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Changes of storm properties in the United States : Observations and multimodel ensemble projections
- 2016
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181. ; 142, s. 41-52
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Tidskriftsartikel (refereegranskat)abstract
- Changes in climate are likely to induce changes in precipitation characteristics including intensity, frequency, duration and patterns of events. In this paper, we evaluate the performance of multiple regional climate models (RCMs) in the North American Regional Climate Change Assessment Program (NARCCAP) to simulate storm properties including storm duration, inter-storm period, storm intensity, and within-storm patterns at eight locations in the continental US. We also investigate the future projections of them based on precipitation from NARCCAP historic runs and future runs. Results illustrate that NARCCAP RCMs are consistent with observed precipitation in the seasonal variation of storm duration and inter-storm period, but fail to simulate the magnitude. The ability to simulate the seasonal trend of average storm intensity varies among locations. Within-storm patterns from RCMs exhibit greater variability than from observed records. Comparisons between RCM-historic simulations and RCM projections indicate that there is a large variation in the future changes in storm properties. However, multi-model ensembles of the storm properties suggest that most regions of the United States will experience future changes in storm properties that includes shorter storm duration, longer inter-storm period, and larger average storm intensity.
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| 5. |
- Ma, Tong, et al.
(författare)
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Endogenous Ovarian Angiogenesis in Polycystic Ovary Syndrome-Like Rats Induced by Low-Frequency Electro-Acupuncture: The CLARITY Three-Dimensional Approach. : Ovarian angiogenesis in PCOS-like rats
- 2018
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Ingår i: International journal of molecular sciences. - : MDPI AG. - 1422-0067. ; 19:11
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Tidskriftsartikel (refereegranskat)abstract
- We sought to determine the role of ovarian vascularity and neo-angiogenesis in the development of mature follicles in polycystic ovary syndrome (PCOS) and to identify any changes induced by low-frequency electro-acupuncture (EA). Twenty-eight 21-day-old female Wistar rats were randomly divided into four groups-Control, Obesity, PCOS-like, and PCOS-like-EA (n = 7/group). Rats in the Obesity group were fed a high-fat diet throughout the experiment. Rats in the PCOS-like and PCOS-like-EA groups were implanted with a sustained-release tube containing 5α-dihydrotestosterone (DHT) beneath the skin of the neck. Rats in the PCOS-like-EA group received low-frequency EA treatment starting at 70 days for 30 min five times a week for four weeks. At the end of the experiment, all rats were euthanized and perfused with hydrogel. The ovaries were collected for clarification and imaging, and ovarian vascularity and neo-angiogenesis were analyzed. Compared with Control and Obesity rats, the ovaries in DHT-induced PCOS-like rats were smaller in size and had fewer mature follicles and corpora lutea. EA increased angiogenesis in the antral follicles of PCOS-like rats, which in turn promoted follicle maturation, ovulation, and CL formation. Therefore, endogenous ovarian angiogenesis plays a very important role in follicular maturation and might be one of the peripheral and direct mechanisms of EA on PCOS.
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| 6. |
- Månsson, Linda K., et al.
(författare)
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A microgel-Pickering emulsion route to colloidal molecules with temperature-tunable interaction sites
- 2020
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 16:7, s. 1908-1921
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Tidskriftsartikel (refereegranskat)abstract
- A simple Pickering emulsion route has been developed for the assembly of temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) microgel particles into colloidal molecules comprising a small number of discrete microgel interaction sites on a central oil emulsion droplet. Here, the surface activity of the microgels serves to drive their assembly through adsorption to growing polydimethylsiloxane (PDMS) emulsion oil droplets of high monodispersity, prepared in situ via ammonia-catalysed hydrolysis and condensation of dimethyldiethoxysilane (DMDES). A dialysis step is employed in order to limit further growth once the target assembly size has been reached, thus yielding narrowly size-distributed, colloidal molecule-like microgel-Pickering emulsion oil droplets with well-defined microgel interaction sites. The temperature-responsiveness of the PNIPAM interaction sites will allow for the directional interactions to be tuned in a facile manner with temperature, all the way from soft repulsive to short-range attractive as the their volume phase transition temperature (VPTT) is crossed. Finally, the microgel-Pickering emulsion approach is extended to a mixture of PNIPAM and poly(N-isopropylmethacrylamide) (PNIPMAM) microgels that differ with respect to their VPTT, this in order to prepare patchy colloidal molecules where the directional interactions will be more readily resolved.
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| 7. |
- Månsson, Linda K., et al.
(författare)
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Preparation of colloidal molecules with temperature-tunable interactions from oppositely charged microgel spheres
- 2019
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 15:42, s. 8512-8524
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Tidskriftsartikel (refereegranskat)abstract
- The self-assembly of small colloidal clusters, so-called colloidal molecules, into crystalline materials has proven extremely challenging, the outcome often being glassy, amorphous states where positions and orientations are locked. In this paper, a new type of colloidal molecule is therefore prepared, assembled from poly(N-isopropylacrylamide) (PNIPAM)-based microgels that due to their well documented softness and temperature-response allow for greater defect tolerance compared to hard spheres and for convenient in situ tuning of size, volume fraction and inter-particle interactions with temperature. The microgels (B) are assembled by electrostatic adsorption onto oppositely charged, smaller-sized microgels (A), where the relative size of the two determines the valency (n) of the resulting core-satellite ABn-type colloidal molecules. Following assembly, a microfluidic deterministic lateral displacement (DLD) device is used to effectively isolate AB4-type colloidal molecules of tetrahedral geometry that possess a repulsive-to-attractive transition on crossing the microgels' volume phase transition temperature (VPTT). These soft, temperature-responsive colloidal molecules constitute highly promising building blocks for the preparation of new materials with emergent properties, and their optical wavelength-size makes them especially interesting for optical applications.
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| 8. |
- Peng, Feifei, et al.
(författare)
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A droplet-based microfluidics route to temperature-responsive colloidal molecules
- 2019
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 123:43, s. 9260-9271
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Tidskriftsartikel (refereegranskat)abstract
- Small clusters of spherical colloids that mimic real molecules, so-called colloidal molecules, hold great promise as building blocks in bottom-up routes to new materials. However, their typical hard sphere nature has hampered their assembly into ordered structures, largely due to a lack of control in the interparticle interactions. To provide easy external control of the interactions, the present work focuses on the preparation of colloidal molecules from temperature-responsive microgel particles that undergo a transition from a soft repulsive to a short-range attractive state as their characteristic volume phase transition temperature (VPTT) is crossed. Preparation of the colloidal molecules starts with the use of a droplet-based microfluidics device to form highly uniform water-in-oil (W/O) emulsion droplets containing, on average and with a narrow distribution, four microgels per droplet. Evaporation of the water then leads to the formation of colloidal molecule-like clusters, which can be harvested following cross-linking and phase transfer. We use a mixture of two types of microgels, one based on poly(N-isopropylacrylamide) (PNIPAM) and the other on poly(N-isopropylmethacrylamide) (PNIPMAM), to prepare bicomponent colloidal molecules, and show that the difference in VPTT between the two allows for induction of attractive interparticle interactions between the PNIPAM interaction sites at temperatures in between the two VPTTs, analogous to the interactions among patchy biomacromolecules such as many proteins.
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| 9. |
- Peng, Feifei
(författare)
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A microfluidic toolbox to fabricate, sort and characterize thermoresponsive colloidal molecules and their assemblies
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we discuss the assembly of thermoresponsive microgel particles into small clusters, and their use as colloidal molecules with specific and directional interactions. The underlying goal is to use these particles as advanced building blocks for new types of self- assembled structures with novel or vastly improved properties, and as model particles for investigating fundamental problems in condensed matter physics. For this purpose, we have developed a microfluidic toolbox to prepare, sort and characterise colloidal molecules and their interactions and self-assembly.In the first part of this thesis, two types of thermoresponsive colloidal particles with different collapse transition temperatures (VPTT) are synthesized based on poly(N-isopropylacrylamide) (PNIPAM) and poly(N-isopropylmethacrylamide) (PNIPMAM), respectively. The mixture of these microgels are encapsulated with a narrow distribution into highly monodisperse water-in-oil droplets generated by developed droplet- based microfluidics. The evaporation of the water inside the droplets leads to clustering of the microgels and the formation of microgel-based colloidal molecules that can then be harvested. These clusters are subsequently crosslinked in order to create stable colloidal molecules, and redispersed into a water phase. The thermoresponsive behavior of these mixed colloidal molecules was studied by confocal microscopy at different temperatures. At 20 °C, both types of microgel interaction sites possess a repulsive interaction behavior, and individual colloidal molecules were observed. In contrast, at 35°C, the PNIPAM-based microgels in the clusters undergo a collapse transition, and their interaction potential changes from soft repulsive to attractive. The PNIPAM particles then act as attractive patches or binding sites, inducing the formation of reversible bonds between individual clusters. These observations confirm that temperature could be used as an external stimulus to control the interactions in these patchy colloidal molecule systems in a highly selective way. Other attractive methods to fabricate large quantities of colloidal molecules are to use electrostatics-driven assembly and a microgel-pickering emulsion approach. However, these strategies used to create colloidal molecules resulted in a mixture of microgel clusters and excess individual microgels. Therefore, we developed and employed microfluidic Deterministic Lateral Displacement (DLD) devices to efficiently separate colloidal molecules from the large background of individual satellite particles. While microgel synthesis can easily be upscaled to obtain large quantities of individual particles, the fabrication of well-defined colloidal molecules and the investigation of their temperature-dependent interactions and the resulting phase diagrams make the question of the individual sample size still an important point to consider. Here we again resort to droplet microfluidics, where we use larger water-in-oil emulsion droplets as our sample container that can be visualised and investigated with a confocal microscope. We have thus designed and fabricated a so-called PhaseChip with multiple storage trap arrays. This device allows us to investigate the interactions between individual particles or patches on different clusters and their assembly into larger superstructures as a function of temperature, pH, ionic strength and particle concentration for a large number of individual samples, while keeping the amount of material required to a minimum.
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