| 1. |
- Cho, Eun, et al.
(författare)
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Clinical experience of tensor-valued diffusion encoding for microstructure imaging by diffusional variance decomposition in patients with breast cancer
- 2022
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Ingår i: Quantitative Imaging in Medicine and Surgery. - : AME Publishing Company. - 2223-4292 .- 2223-4306. ; 12:3, s. 2002-2017
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diffusion-weighted imaging plays a key role in magnetic resonance imaging (MRI) of breast tumors. However, it remains unclear how to interpret single diffusion encoding with respect to its link with tissue microstructure. The purpose of this retrospective cross-sectional study was to use tensor-valued diffusion encoding to investigate the underlying microstructure of invasive ductal carcinoma (IDC) and evaluate its potential value in a clinical setting. Methods: We retrospectively reviewed biopsy-proven breast cancer patients who underwent preoperative breast MRI examination from July 2020 to March 2021. We reviewed the MRI of 29 patients with 30 IDCs, including analysis by diffusional variance decomposition enabled by tensor-valued diffusion encoding. The diffusion parameters of mean diffusivity (MD), total mean kurtosis (MKT), anisotropic mean kurtosis (MKA), isotropic mean kurtosis (MKI), macroscopic fractional anisotropy (FA), and microscopic fractional anisotropy (μFA) were estimated. The parameter differences were compared between IDC and normal fibroglandular breast tissue (FGBT), as well as the association between the diffusion parameters and histopathologic items. Results: The mean value of MD in IDCs was significantly lower than that of normal FGBT (1.07±0.27 vs. 1.34±0.29, P<0.001); however, MKT, MKA, MKI, FA, and μFA were significantly higher (P<0.005). Among all the diffusion parameters, MKI was positively correlated with the tumor size on both MRI and pathological specimen (rs=0.38, P<0.05 vs. rs=0.54, P<0.01), whereas MKT had a positive correlation with the tumor size in the pathological specimen only (rs=0.47, P<0.02). In addition, the lymph node (LN) metastasis group had significantly higher MKT, MKA, and μFA compared to the metastasis negative group (P<0.05). Conclusions: Tensor-valued diffusion encoding enables a useful non-invasive method for characterizing breast cancers with information on tissue microstructures. Particularly, μFA could be a potential imaging biomarker for evaluating breast cancers prior to surgery or chemotherapy.
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| 2. |
- Kim, Min-Jeong, et al.
(författare)
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Independent enhancement of the in-plane Seebeck effect in 2D PtSe2/PtSe2 homostructures via a facile interface tuning method
- 2024
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Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 268
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Tidskriftsartikel (refereegranskat)abstract
- Atomically thin two-dimensional (2D) transition-metal dichalcogenide (TMDC) films have emerged as promising semiconducting materials for use in thermoelectric (TE) applications. However, the utilization of such materials remains challenging owing to the relatively high intrinsic resistance as the size of the TMDC thin films increases to the centimeter scale. These 2D TMDC films can also form vertically stacked homo- or heterostructures at large interfaces with other 2D TMDC films, resulting in unique TE properties at room temperature. This article reports on the in-plane TE properties when the interfaces formed within a PtSe2/PtSe2 (3 nm/3 nm) homostructure are modulated as a function of O2 plasma treatment time. The results show enhanced Seebeck coefficients compared with that of the single-layer PtSe2 with the same thickness. The independent enhancement in the Seebeck coefficient while keeping the electrical conductivity leads to a substantial increase in the power factor. Such extra Seebeck voltage in 2D PtSe2/PtSe2 homostructures is mainly as a result of momentum exchange by charge carriers caused by the temperature gradient in the vertical direction, which occurs in-plane Seebeck coefficient measurements, at the interface between the PtSe2 layers in the in-plane temperature gradient along the samples. These results resemble the characteristics of the phonon drag effect at low temperatures, which can independently increase the Seebeck coefficient at room temperature.
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| 3. |
- Kim, Min-Jeong, et al.
(författare)
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Intrinsic Seebeck coefficients of 2D polycrystalline PtSe2 semiconducting films through two-step annealing
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 11:11, s. 5714-5724
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Tidskriftsartikel (refereegranskat)abstract
- Because of the high contact resistance between a metal and a film, evaluating the intrinsic Seebeck coefficient of large-area two-dimensional (2D) semiconducting films with high-resistance is challenging. Here, we report a simple scheme to measure the large-area Seebeck coefficients of 2D polycrystalline platinum diselenide (PtSe2) thin films, whose electrical resistance (>2 M omega) is too high to measure the thermoelectric (TE) properties, by thermal annealing. As-prepared PtSe2 thin films deposited on sapphire substrates and treated by a two-step thermal annealing process at 574 K exhibited an intrinsic Seebeck coefficient > similar to 160 mu V K-1, which is 400% higher than that of the single-crystalline PtSe2 bulk, under a temperature gradient of up to 5 K along the samples. In addition, we confirm that the in-plane Seebeck coefficient of the two-step annealed samples was independent of the metal electrode. In addition, the role of thermal annealing in intrinsically-high-resistance 2D PtSe2 semiconducting films based on the atomic-scale crystallographic characteristics of these films and the measured contact resistance between the metal and PtSe2 layer is further discussed. Our finding represents an important achievement in understanding and measuring the Seebeck effect of high-TE-performance 2D layered transition metal dichalcogenide materials.
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| 4. |
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| 5. |
- Shim, Kyu Hwan, et al.
(författare)
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Subsequent correlated changes in complement component 3 and amyloid beta oligomers in the blood of patients with Alzheimer's disease
- 2024
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Ingår i: ALZHEIMERS & DEMENTIA. - 1552-5260 .- 1552-5279.
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTIONAlzheimer's disease (AD) involves the complement cascade, with complement component 3 (C3) playing a key role. However, the relationship between C3 and amyloid beta (A beta) in blood is limited.METHODSPlasma C3 and A beta oligomerization tendency (A beta Ot) were measured in 35 AD patients and 62 healthy controls. Correlations with cerebrospinal fluid (CSF) biomarkers, cognitive impairment, and amyloid positron emission tomography (PET) were analyzed. Differences between biomarkers were compared in groups classified by concordances of biomarkers.RESULTSPlasma C3 and A beta Ot were elevated in AD patients and in CSF or amyloid PET-positive groups. Weak positive correlation was found between C3 and A beta Ot, while both had strong negative correlations with CSF A beta 42 and cognitive performance. Abnormalities were observed for A beta Ot and CSF A beta 42 followed by C3 changes.DISCUSSIONIncreased plasma C3 in AD are associated with amyloid pathology, possibly reflecting a defense response for A beta clearance. Further studies on A beta-binding proteins will enhance understanding of A beta mechanisms in blood.
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| 6. |
- Choi, Jae Won, et al.
(författare)
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Interface-driven seebeck effect in two-dimensional trilayer-stacked PtTe2/MoS2/MoS2 heterostructures via electron-electron interactions
- 2023
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Ingår i: Nano Energy. - : Elsevier. - 2211-2855 .- 2211-3282. ; 115
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) platinum telluride (PtTe2), which is one of the promising metallic transition metal dichalcogenides, has been proven as an essential candidate for electronic devices, magnetic devices, type-II Dirac fermions, topological superconductors, and other optoelectronic applications. However, the formation and thermal transport as important thermoelectric (TE) device applications have not been realized in large-area 2D PtTe2 films due to their semi-metallic properties. Here, we report an innovative approach to enhance the in-plane TE power factors by piling the metallic PtTe2 films on high-resistance (> 10 MO) intrinsic MoS2 films to form bilayer-PtTe2/MoS2 (5 nm/7 nm)//sapphire and trilayer-PtTe2/MoS2/MoS2 (5 nm/7 nm/7 nm)//sapphire heterostructures via wet-transfer stacking method. Such approaches can be achieved by utilizing 2D/2D heterostructure to increase the electron effective mass due to the strong electron-electron interaction at interface under temperature gradient along the samples and ultimately increase Seebeck coefficients via interface-driven Seebeck effect along with a metallic high-conductivity top-PtTe2 films. The trilayer-stacked PtTe2/MoS2/MoS2 heterostructures exhibit an extremely high Seebeck coefficient of 21.6 mu V/K and power factor of similar to 0.2 mW/m.K-2, which are 231 % and similar to 727 %, higher than those of the metallic 5-nm-thick single PtTe2 film on the sapphire substrate, respectively. Our new physics and observation can pave the way toward an effective strategy for understating 2D/2D TMDC heterostructure materials for high Fig.-of-merit TE energy harvesting devices.
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| 7. |
- Kanoni, Stavroula, et al.
(författare)
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Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis.
- 2022
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Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-760X .- 1465-6906 .- 1474-7596. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery.To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N=1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3-5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism.Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.
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| 8. |
- Chen, Zhishan, et al.
(författare)
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Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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| 9. |
- Cho, Sung Min, et al.
(författare)
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Development of Novel VEGFR2 Inhibitors Originating from Natural Product Analogues with Antiangiogenic Impact
- 2021
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 64:21, s. 15858-15867
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Tidskriftsartikel (refereegranskat)abstract
- A novel natural small molecule, voacangine (Voa), has been discovered as a potent antiangiogenic compound. Notably, Voa directly binds the kinase domain of the vascular endothelial growth factor receptor 2 (VEGFR2) and thereby inhibits downstream signaling. Herein, we developed synthetic small molecules based on the unique chemical structure of Voa that directly and specifically target and modulate the kinase activity of VEGFR2. Among these Voa structure analogues, Voa analogue 19 (V19) exhibited increased antiangiogenic potency against VEGF-induced VEGFR2 phosphorylation without cytotoxic effects. Moreover, treatment with V19 resulted in significant tumor cell death in a mouse xenograft model. In conclusion, this new VEGFR2 modulator, inspired from the rigid scaffold of a natural compound, Voa, is presented as a potent candidate in the development of new antiangiogenic agents.
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| 10. |
- Fernandez-Rozadilla, Ceres, et al.
(författare)
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Deciphering colorectal cancer genetics through multi-omic analysis of 100,204 cases and 154,587 controls of European and east Asian ancestries
- 2023
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 55, s. 89-99
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal cancer (CRC) is a leading cause of mortality worldwide. We conducted a genome-wide association study meta-analysis of 100,204 CRC cases and 154,587 controls of European and east Asian ancestry, identifying 205 independent risk associations, of which 50 were unreported. We performed integrative genomic, transcriptomic and methylomic analyses across large bowel mucosa and other tissues. Transcriptome- and methylome-wide association studies revealed an additional 53 risk associations. We identified 155 high-confidence effector genes functionally linked to CRC risk, many of which had no previously established role in CRC. These have multiple different functions and specifically indicate that variation in normal colorectal homeostasis, proliferation, cell adhesion, migration, immunity and microbial interactions determines CRC risk. Crosstissue analyses indicated that over a third of effector genes most probably act outside the colonic mucosa. Our findings provide insights into colorectal oncogenesis and highlight potential targets across tissues for new CRC treatment and chemoprevention strategies.
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