| 1. |
- Adnane, Bouchaib, et al.
(författare)
-
Mid/far-infrared detection using a MESFET with B-modulation doped Ge-dot/SiGe-well multiple stacks in the channel region
- 2004
-
Konferensbidrag (refereegranskat)abstract
- Multiple modulation-doped Ge-dot/SiGe-QW stack structures were grown using MBE, and processed as FET devices for mid/far infrared detection. From a non-optimized device, a broadband photoresponse has been observed in the mid-infrared range of 3-15 μm. A peak responsivity was estimated to be as high as 100 mA/W at T= 20 K. This work indicates that SiGE QD/QW structures using the lateral transport geometry can be a potential candidate for photodetectors operating in far-infrared range.
|
|
| 2. |
|
|
| 3. |
- Qiu, Jian-xin, et al.
(författare)
-
[Study of sensitivity to impulse noise in guinea pig, rat and mouse]
- 2004
-
Ingår i: Zhonghua er bi yan hou ke za zhi. - 0412-3948. ; 39:8, s. 472-475
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study sensitivity to impulse noise in guinea pig, rat and mice. METHODS: Six groups were divided. Group I: Guinea pigs (n = 5) were exposed to 50 impulses of 160 dB SPL; Group II: Guinea pigs (n = 5) were exposed to 100 impulses of 160 dB SPL; Group III: Guinea pigs (n = 5) were exposed to 200 impulses of 160 dB SPL; Group IV: Guinea pigs (n = 6) were exposed 400 impulses of 160 dB SPL; Group V: Rats (n = 10) were exposed to 50 impulses of 160 dB SPL; Group VI: Mice (n = 10) were exposed to 50 impulses of 160 dB SPL. ABR thresholds were determined prior to, immediately, one day, one week, two weeks and four weeks after impulse noise exposure. RESULTS: The rat and mice were shown temporary threshold shift (TTS) and permanent threshold shift (PTS) after 50 times impulse noise (160), while no TTS and PTS in the guinea pigs but it was shown TTS and PTS after 400 times impulse noise (160). CONCLUSIONS: Sensitivity to impulse noise is different among guinea pig, rat and mouse. Guinea pig has less sensitivity to impulse noise while rat and mouse have higher sensitivity to impulse noise. In addition, rat has higher sensitivity to impulse noise than mouse.
|
|
| 4. |
- Xin, Sun, et al.
(författare)
-
A novel protein localized to the fibrillar compartment of the nucleolus and to the brush border of a secretory cell
- 2002
-
Ingår i: European Journal of Cell Biology. - : Elsevier BV. - 0171-9335 .- 1618-1298. ; 81:3, s. 125-137
-
Tidskriftsartikel (refereegranskat)abstract
- We report the identification and molecular characterization of a novel abundant nucleolar protein of the dipteran Chironomus tentans. As shown by Western blot analysis, this protein is present in nuclear extracts in a phosphorylated form with a mobility corresponding to 100 kDa. Therefore, the protein has been termed Chironomus tentans p100, or p100 for short. Analysis of the cDNA-derived primary structure of p100 indicates a protein that contains a combination of structural domains which could be involved in interactions with proteins and nucleic acids: twelve alternating acidic and basic repeats, a glycine-arginine-rich domain and a region with two zinc fingers of the C4-type. Acidic and basic repeats are typical for a group of nonribosomal nucleolar proteins. The best-studied representatives of this group are Nopp140 and nucleolin, proteins with structural and regulatory functions in rDNA transcription. Immunocytology and immunoelectron microscopy of Chironomus tentans salivary gland cells have shown that the p100 protein is located in the fibrillar compartment of the nucleolus, while it is almost absent from the granular compartment and from the nucleoplasm. The p100 protein remains in the nucleolus after removal of RNA and DNA by digestion with nucleases. This indicates that p100 might be a constituent of the nucleolar proteinaceous framework. Remarkably, p100 is also localized in the brush border in the apical part of the salivary gland cell. The presence of p100 both in the nucleolus and at the apical plasma membrane suggests that it could be involved in coordination of the level of protein production and export from the cell through regulation of the level of rRNA production in the nucleolus.
|
|
| 5. |
- Zhao, CM, et al.
(författare)
-
Chronic Helicobacter pylori infection results in gastric hypoacidity and hypergastrinemia in wild-type mice but vagally induced hypersecretion in gastrin-deficient mice
- 2003
-
Ingår i: Regulatory Peptides. - 1873-1686. ; 115:3, s. 161-170
-
Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori infection is a causal factor of gastric cancer (which is associated with low gastric acid secretion) or duodenal ulcer (high acid secretion). Parietal cells and ECL cells in the stomach are controlled by gastrin, which plays a crucial role in the regulation of acid secretion. The present study was undertaken to identify a possible role of gastrin in determining the different responses of the parietal cells and ECL cells to chronic H. pylori infection. Wild-type (C57BL/6J) gastrin(+/+) mice and gastrin(-/-) knockout mice, generated through targeted gene disruption and backcrossed eight times to C57BL/6J, were infected with H. pylori for 9 months. The acid output was measured 4 h after pylorus ligation (known to cause vagal excitation). The gastric mucosa was examined by immunocytochemistry with antisera to alpha-subunit of H+/K+-ATPase for the parietal cells, and to histamine and vesicle monoamine transporter-2 for the ECL cells, and by quantitative electron microscopy. In infected gastrin(+/+) mice, the acid output and the percentage of secreting parietal cells (freely fed state) were 20-30% of the values in uninfected controls, while the density and ultrastructure of parietal cells were normal. The infected mice had hypergastrinemia and displayed hypertrophy and hyperplasia of ECL cells. Although uninfected gastrin(-/-) mice had lower the acid output than uninfected gastrin(+/+) mice, there was a higher acid output (similar to 3 times) in infected gastrin(-/-) mice than their uninfected homologues. The numbers of parietal cells and ECL cells remained unchanged in infected gastrin(-/-) mice. In conclusion, chronic H. pylori infection results to impaired parietal-cell function (acid hyposecretion), hypergastrinemia and hyperplasia of ECL cells in wild-type mice but leads to vagally induced hypersecretion in gastrin-deficient mice. (C) 2003 Elsevier B.V All rights reserved.
|
|
| 6. |
|
|
