| 1. |
- Du, Yaoyao, et al.
(författare)
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Cartilage Oligomeric Matrix Protein Inhibits Vascular Smooth Muscle Calcification by Interacting With Bone Morphogenetic Protein-2.
- 2011
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Ingår i: Circulation Research. - 1524-4571. ; 108, s. 79-917
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Vascular calcification is a significant contributor to cardiovascular morbidity and mortality. We recently reported that cartilage oligomeric matrix protein (COMP) is pivotal for maintaining the homeostasis of vascular smooth muscle cells (VSMCs). Whether COMP affects the process of vascular calcification is unknown. Objective: We aimed to test whether COMP modulates vascular calcification. Methods and Results: VSMC calcification in vitro was induced by calcifying media containing high inorganic phosphate or calcium. In vivo medial vessel calcification was induced in rats by 5/6 nephrectomy with a high-phosphate diet or by periadventitial application of CaCl(2) to the abdominal aorta. COMP protein level was markedly reduced in both calcified VSMCs and arteries. COMP deficiency remarkably exacerbated VSMC calcification, whereas ectopic expression of COMP greatly reduced calcification. Furthermore, COMP knockdown facilitated osteogenic markers expression by VSMCs even in the absence of calcifying media. By contrast, COMP overexpression significantly inhibited high phosphate- or high calcium-induced VSMC osteochondrogenic transition. Induction of osteogenic marker expression by COMP silencing was reversed by a soluble form of bone morphogenetic protein (BMP)-2 receptor IA, which suggests a BMP-2-dependent mechanism. Our data revealed that COMP bound directly to BMP-2 through the C terminus, inhibited BMP-2 receptor binding, and blocked BMP-2 osteogenic signaling, indicating COMP inhibits osteochondrogenic transition of VSMCs at least partially through inhibiting BMP-2. Conclusions: Our data strongly suggest that COMP is a novel inhibitor of vascular calcification. The imbalance between the effects of COMP and BMP-2 may provide new insights into the pathophysiology of vascular calcification.
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| 2. |
- Han, Yi, et al.
(författare)
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Abnormal strain in suspended GeSn microstructures
- 2018
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Ingår i: Materials Research Express. - : IOP Publishing. - 2053-1591. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- A suspended GeSn microstructure is realized by a two-step selective wet etching technique with the aim of fully relaxing the compressive strain, promoting the indirect to direct bandgap transition and improving the optical property of GeSn thin films grown on Ge. The compressive strain was found efficiently relaxed, and even unexpected large tensile strain was displayed on regions of the microstructure by micro-Raman spectroscopy. Residual Ge patches under the suspended GeSn microstructure were found by scanning electron microscopy and proved to be the origin of the tensile strain by finite element method simulations. The tensile strain on the surface is beneficial for direct bandgap conversion and carrier accumulation. Significant enhancement of photoluminescence was obtained in the GeSn microstructures than the original thin film.
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| 3. |
- Li, Yuhong, et al.
(författare)
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Oxygen availability determines key regulators in soil organic carbon mineralisation in paddy soils
- 2021
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; , s. 108106-108106
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Tidskriftsartikel (refereegranskat)abstract
- Rice paddy agro-ecosystems play an important role in global carbon (C) sequestration. Because of flooding management, paddy soil experience periodical changes in oxygen availability, which may make soil organic carbon (SOC) mineralisation unique as compared to upland or other wetland ecosystems. However, at present, information about the relevant mechanisms involved in paddy SOC mineralisation is limited and unclear. We selected three paddy soils with variable iron (Fe) contents, which were either fumigated with chloroform (to reduce microbial biomass) or remained un-fumigated. Soils were incubated for 78 days in one of three treatments: alternating nonflooded–flooded (NF: moist for 0–30 days (oxygen-abundant) and flooded for 31–78 days (oxygen-limited)), continuously flooded (CF: oxygen-limited), and continuously anaerobically flooded (AF: oxygen-depleted). Fumigation reduced the microbial biomass C by more than 70%. Except for the nonflooded period in the NF treatment, the SOC mineralisation rate, at the late stage of each treatment, was significantly lower in the fumigated than in the un-fumigated soil. A multiple regressions showed that a reduction in dissolved organic C contents over time contributed to the cumulative SOC mineralisation only during the nonflooded period in the NF treatment. Furthermore, the labile C pool size was smaller in the AF treatment relative to the other treatments. These imply that dissolved substrates in oxygen-depleted paddy soil were of greater recalcitrance, most likely due to thermodynamic reasons. SOC mineralisation correlated with changes in the redox potential and the Fe2+ contents in the CF and AF treatments only. This indicates that under oxygen-limited and -depleted conditions, Fe played a significant role as an electron acceptor during SOC mineralisation. Correlation and linear regression analyses also suggest that Fe influenced dissolved organic C contents, and hydrolase and oxidative activities. Our findings show that SOC bioavailability is a rate-limiting factor for SOC mineralisation, but only under oxygen-abundant conditions. However, under oxygen-limited or -depleted conditions, microbial biomass, the recalcitrance of organic C compounds, and the availability of electron acceptors are key regulators in determining the intensity and rate of SOC mineralisation.
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| 4. |
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| 5. |
- Liu, Juanjuan, et al.
(författare)
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Electrically injected GaAsBi/GaAs single quantum well laser diodes
- 2017
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 7:11, s. Article Number: 115006 -
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Tidskriftsartikel (refereegranskat)abstract
- We present electrically injected GaAs/GaAsBi single quantum well laser diodes (LDs) emitting at a record long wavelength of 1141 nm at room temperature grown by molecular beam epitaxy. The LDs have excellent device performances with internal quantum efficiency of 86%, internal loss of 10 cm-1 and transparency current density of 196 A/cm2. The LDs can operate under continuous-wave mode up to 273 K. The characteristic temperature are extracted to be 125 K in the temperature range of 77?150 K, and reduced to 90 K in the range of 150?273 K. The temperature coefficient of 0.3 nm/K is extracted in the temperature range of 77?273 K.
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| 6. |
- Pan, Wenwu, et al.
(författare)
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Photoluminescence of InGaAs/GaAsBi/InGaAs type-II quantum wells grown by gas source molecular beam epitaxy
- 2017
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 32:1
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Tidskriftsartikel (refereegranskat)abstract
- InxGa1-xAs/GaAs1-yBiy/InxGa1-xAs (0.20 ≤x ≤0.22, 0.035 ≤y ≤0.045) quantum wells (QWs) were grown on GaAs substrates by gas source molecular beam epitaxy for realizing the type-II band edge line-up. Both type-I and type-II transitions were observed in the Bi containing W QWs and the photoluminescence intensity was enhanced in the sample with a high Bi content, which is mainly due to the improvement of carrier confinement. The 8 band k • p model was used to analyze the electronic properties in the QWs and the calculated transition energies fit well with the experiment results. Our study shows that the proposed type-II QW is a promising candidate for realizing GaAs-based near infrared light emitting devices near 1.3 μm
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| 7. |
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| 8. |
- Wang, Shu Min, 1963, et al.
(författare)
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Electrically pumped GaAsBi laser diodes
- 2017
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Ingår i: International Conference on Transparent Optical Networks. - 2162-7339. - 9781538608586
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present electrically pumped GaAsBi quantum well (QW) laser diodes (LDs) grown by molecular beam epitaxy. The LDs reveal a record long lasing wavelength of 1.14 μm at 300 K and can be operated under CW excitation up to 273 K. They also show high performance with an internal quantum efficiency of 86% and an internal optical loss of 10 cm-1. The characteristic temperature is 79 K in the temperature range of 225-350 K and the temperature coefficient of the lasing wavelength is 0.26 nm/K at 77 - 350 K, much smaller than 0.35 - 0.40 nm/K for InGaAs and InGaAsP QW LDs. These results suggest that GaAsBi LDs are attractive candidates for uncooled near infrared lasers on GaAs.
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| 9. |
- Wang, Shu Min, 1963, et al.
(författare)
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Light emitting devices of dilute bismides
- 2017
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Ingår i: 8th International Workshop on Bi-containing Semiconductors, Marburg, Germany, July 23-26, 2017 (invited talk).
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Konferensbidrag (refereegranskat)
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| 10. |
- Wang, Shu Min, 1963, et al.
(författare)
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Novel Dilute Bismides for IR Optoelectronics Applications
- 2013
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Ingår i: Asia Communications and Photonics Conference, ACP. - Washington, D.C. : OSA. - 2162-108X.
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Konferensbidrag (refereegranskat)abstract
- III-V-Bi compounds reveal a number of attractive physical properties promising for novel IR optoelectronic applications [1,2] and have received considerable attention as witnessed by the dedicated international workshops on this topic in the consecutive past four years. The isoelectronic nature of Bi atoms in III-Vs induces strong interactions with the energy bands of host materials leading to large band-gap reduction, less temperature sensitive band-gap and large spin-orbit split band. So far the most studied material is Ga(N)AsBi, while other dilute bismides have also been reported recently. In this paper, we shall briefly review several novel bismides: GaSbBi, InSbiBi, InAsBi, InPBi and InGaAsBi, and the Bi surfactant effect from our group, all grown by molecular beam epitaxy (MBE).
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