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Biomedical subjects

C L Yang

Publications and source records attributed to C L Yang.

At least 19 recordsLinked to original sources
PubMed2006

Spectral dependence of spin photocurrent and current-induced spin polarization in an InGaAs/InAlAs two-dimensional electron gas.

The converse effects of spin photocurrent and current induced spin polarization are experimentally demonstrated in a two-dimensional electron gas system with Rashba spin splitting. Their consistency with the strength of the Rashba coupling as measured for the same system from beating of the Shubnikov-de Haas oscillations reveals a unified picture for the spin photocurrent, current-induced spin-polarization, and spin-orbit coupling. In addition, the observed spectral inversion of the spin photocurrent indicates a system with dominating structure inversion asymmetry.

Journal Article↗
PubMed2005

An elderly female who survived more than 30 years following a diagnosis of Takayasu's arteritis, complicated by fatal intestinal amyloidosis.

Compared to young patients with Takayasu's arteritis (TA), little information about elderly patients with TA has been reported. Additionally, no reports were found regarding TA cases with complications of intestinal amyloidosis. This is a case report of an elderly female, who developed intestinal amyloidosis, during late-stage TA. After years of outpatient management, she developed sudden severe dyspnea with pulmonary effusion, requiring hospitalization. After this event, betamethasone was replaced by methotrexate (MTX) for the next 34 months, but it seemed ineffective. After 1.5 years, she developed intractable diarrhea, followed by increases in BUN and serum creatinine (Cr), requiring several courses of hemodialysis. Colonoscopy revealed the presence of amyloid in her intestine, although she died of complicated sepsis caused by MRSA infection. This may be the first paper describing intestinal amyloidosis in a TA patient. Additionally, her case is rare in that she lived more than 30 years after the onset and diagnosis of TA.

Aged↗
PubMed2004

Low energy electron irradiation induced deep level defects in 6H-SiC: the implication for the microstructure of the deep levels E1/E2.

N-type 6H-SiC samples irradiated with electrons having energies of E(e)=0.2, 0.3, 0.5, and 1.7 were studied by deep level transient technique. No deep level was detected at below 0.2 MeV irradiation energy while for E(e)>/=0.3 MeV, deep levels ED1, E(1)/E(2), and E(i) appeared. By considering the minimum energy required to displace the C atom or the Si atom in the SiC lattice, it is concluded that generation of the deep levels E(1)/E(2), as well as ED1 and E(i), involves the displacement of the C atom in the SiC lattice.

Journal Article↗
PubMed2003

Observation of microwave-induced zero-conductance state in Corbino rings of a two-dimensional electron system.

Using Corbino samples we have observed oscillatory dc conductance in a high-mobility two-dimensional electron system when it is subjected to crossed microwave and magnetic fields. At the strongest of the oscillation minima the conductance is found to be vanishingly small, indicating a macroscopic insulating state associated with this minimum. With increasing voltage bias, a crossover from Ohmic to electron-heating regime is observed.

Journal Article↗
PubMed2002

Zener tunneling between landau orbits in a high-mobility two-dimensional electron gas.

Magnetotransport in a laterally confined two-dimensional electron gas (2DEG) can exhibit modified scattering channels owing to a tilted Hall potential. Transitions of electrons between Landau levels with shifted guiding centers can be accomplished through a Zener tunneling mechanism, and make a significant contribution to the magnetoresistance. A remarkable oscillation effect in weak field magnetoresistance has been observed in high-mobility 2DEGs in GaAs -Al Ga 0.3As (0.7) heterostructures, and can be well explained by the Zener mechanism.

Journal Article↗
PubMed2001

Identification of a chloride-formate exchanger expressed on the brush border membrane of renal proximal tubule cells.

A key function of the proximal tubule is retrieval of most of the vast quantities of NaCl and water filtered by the kidney. Physiological studies using brush border vesicles and perfused tubules have indicated that a major fraction of Cl(-) reabsorption across the apical membrane of proximal tubule cells occurs via Cl(-)-formate exchange. The molecular identity of the transporter responsible for renal brush border Cl(-)-formate exchange has yet to be elucidated. As a strategy to identify one or more anion exchangers responsible for mediating Cl(-) reabsorption in the proximal tubule, we screened the expressed sequence tag database for homologs of pendrin, a transporter previously shown to mediate Cl(-)-formate exchange. We now report the cDNA cloning of CFEX, a mouse pendrin homolog with expression in the kidney by Northern analysis. Sequence analysis indicated that CFEX very likely represents the mouse ortholog of human SLC26A6. Immunolocalization studies detected expression of CFEX, but not pendrin, on the brush border membrane of proximal tubule cells. Functional expression studies in Xenopus oocytes demonstrated that CFEX mediates Cl(-)-formate exchange. Taken together, these observations identify CFEX as a prime candidate to mediate Cl(-)-formate exchange in the proximal tubule and thereby to contribute importantly to renal NaCl reabsorption. Given its wide tissue distribution, CFEX also may contribute to transcellular Cl(-) transport in additional epithelia such as the pancreas and contribute to transmembrane Cl(-) transport in nonepithelial tissues such as the heart.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2001

The processing of coreference for reduced expressions in discourse integration.

Three reading-time experiments in Chinese are reported that test contrasting views of how pronominal coreference is achieved. On the one hand, studies of reading time and eye tracking suggest that reduced expressions, such as the pronoun he, serve as critical links to integrate separate utterances into a coherent model of discourse. On the other hand, probe-word recognition studies indicate that full anaphoric expressions, such as a repeated name, are more readily interpreted than reduced expressions due to their rich lexical information, which provides effective cues to match the representation of the appropriate referent in memory. The results indicate that the ease of integrating the critical referent into a model of discourse is a function of the congruence of lexical, semantic, and discourse features conveyed by a syntactically prominent reduced expression within linguistic input. This pattern supports the view that a reduced expression is interpreted on-line and indeed plays a critical role in promoting discourse coherence by facilitating the semantic integration of separate utterances.

Adult↗
PubMed2001

Role of sodium/hydrogen exchanger isoform NHE3 in fluid secretion and absorption in mouse and rat cholangiocytes.

Na+/H+ exchanger (NHE) isoforms play important roles in intracellular pH regulation and in fluid absorption. The isoform NHE3 has been localized to apical surfaces of epithelia and in some tissues may facilitate the absorption of NaCl. To determine whether the apical isoform NHE3 is present in cholangiocytes and to examine whether it has a functional role in cholangiocyte fluid secretion and absorption, immunocytochemical studies were performed in rat liver with NHE3 antibodies and functional studies were obtained in isolated bile duct units from wild-type and NHE3-/- mice after stimulation with forskolin, using videomicroscopic techniques. Our results indicate that NHE3 protein is present on the apical membranes of rat cholangiocytes and on the canalicular membrane of hepatocytes. Western blots also detect NHE3 protein in rat cholangiocytes and isolated canalicular membranes. After stimulation with forskolin, duct units from NHE3-/- mice fail to absorb the secreted fluid from the cholangiocyte lumen compared with control animals. Similar findings were observed in isolated bile duct units from wild-type mice and rats in the presence of the Na+/H+ exchanger inhibitor 5-(N-ethyl-N-isopropyl)-amiloride. In contrast, we could not demonstrate absorption of fluid from the canalicular lumen of mouse or rat hepatocyte couplets after stimulation of secretion with forskolin. These findings indicate that NHE3 is located on the apical membrane of rat cholangiocytes and that this NHE isoform can function to absorb fluid from the lumens of isolated rat and mouse cholangiocyte preparations.

Absorption↗
PubMed2001

Essential role of NHE3 in facilitating formate-dependent NaCl absorption in the proximal tubule.

The absorption of NaCl in the proximal tubule is markedly stimulated by formate. This stimulation of NaCl transport is consistent with a cell model involving Cl(-)-formate exchange in parallel with pH-coupled formate recycling due to nonionic diffusion of formic acid or H(+)-formate cotransport. The formate recycling process requires H(+) secretion. Although Na(+)-H(+) exchanger isoform NHE3 accounts for the largest component of H(+) secretion in the proximal tubule, 40-50% of the rates of HCO absorption or cellular H(+) extrusion persist in NHE3 null mice. The purpose of the present investigation is to use NHE3 null mice to directly test the role of apical membrane NHE3 in mediating NaCl absorption stimulated by formate. We demonstrate that formate stimulates NaCl absorption in the mouse proximal tubule microperfused in vivo, but the component of NaCl absorption stimulated by formate is absent in NHE3 null mice. In contrast, stimulation of NaCl absorption by oxalate is preserved in NHE3 null mice, indicating that oxalate-stimulated NaCl absorption is independent of Na(+)-H(+) exchange. The virtually complete dependence of formate-induced NaCl absorption on NHE3 activity raises the possibility that NHE3 and the formate transporters are functionally coupled in the brush border membrane.

Absorption↗
PubMed2001

[Indicators of quality of care in nursing homes from the perspective of elderly residents].

The purpose of this study was to explore the indicators of quality of care in nursing homes from the perspective of residents. A qualitative research method with in-depth interviews and participant observation was used to collect the data. Sample consisted of 10 residents from three accredited nursing homes in Keelung, Chia-I, and Kaohsiung. The study found 7 groups of indicators of quality of care for nursing homes including indicators of environment, nursing professional competence, quality assurance, basic human rights, direct care attitude, social interaction, and needs satisfaction. Findings of this study may sensitize long-term care professionals to the needs of nursing home residents. These findings can also provide a basis for setting indicators for nursing home quality evaluation and for further improvement of the life quality of nursing home residents.

Aged↗
PubMed2000

Oxidation of nitric oxide in a two-stage chemical scrubber using dc corona discharge.

The dc corona was studied as an alternative for NO oxidation in a two-stage chemical scrubber. The dc corona plasma reactor completely oxidized 150ppm of NO to NO2 in an air stream. The NO2 was further oxidized at a higher voltage. For some cases, the NO2 in the effluents of the plasma reactor was absorbed quantitatively by a caustic sodium sulfite aqueous solution in a 2l bubble column gas absorber. The outlet concentrations of both NO and NO2 from the plasma-scrubber combination system (corona-induced chemical scrubber) were below the detection limit of the chemiluminescent NOx analyzer.

Air Pollutants↗
PubMed2000

Induction of integrin-associated protein (IAP) mRNA expression during memory consolidation in rat hippocampus.

We have previously demonstrated that hippocampal integrin-associated protein (IAP) gene expression is associated with memory formation in a one-way inhibitory avoidance learning in rats. In the present study, we further investigated the role and mechanism of IAP involved in memory consolidation in rats. Because of the minute amount of IAP present in the brain, we have adopted the quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Our results revealed that hippocampal IAP mRNA expression is approximately fourfold higher in rats showing good memory retention (GM, retention score of 600 s) at 3 h, but not at other time points, after training when compared with the poor memory rats (retention score < 80 s). On the other hand, integrin alphav mRNA level was markedly increased ( approximately twofold), while integrin beta3 mRNA level was decreased ( approximately 50%) at 1 h post-training. Further, separate sets of RT-PCR analysis revealed that IAP5 and IAP6 mRNA expressions, but not that of IAP7, were markedly increased in GM rats 3 h post-training. Moreover, regional distribution studies revealed that different isoforms of the IAP gene are similarly distributed in different brain areas, while IAP7 has been the predominant form present in astrocyte cells. These results together suggest that IAP mRNA expression is indeed induced upon training, rather than that the GM rats have constitutively higher levels of IAP. The unparallel change of IAP and integrin mRNA expressions as far as time-course is concerned suggests that they are possibly involved in different forms and stages of memory processing. Further, IAP5 and IAP6 are more closely associated with memory consolidation, while IAP7 may constitute the major isotype for signal transduction in astrocyte cells.

Alternative Splicing↗
PubMed2000

Removal of chromium from abrasive blast media by leaching and electrochemical precipitation.

Water is effective in leaching out Cr6+ from a mixture of paint powders and abrasive blast media. However, acids such as HNO3, HCl, and H2SO4 significantly enhance the leaching procedure. Cr ions in the leaching solutions are successfully removed by electrochemical precipitation. The consumable Fe electrodes generate ferrous ions to cause the reduction of Cr6+ to Cr3+. Cr3+ ions along with Fe2+ and Fe3+ are then removed mainly by precipitation as Cr(OH)3, Fe(OH)2, and Fe(OH)3 near the cathode where OH- ions are generated by water electrolysis. The electrochemical process is capable of discharging low levels of Cr6+, less than 1 mg/L, without pH adjustment.

Chromium↗
PubMed2000

The use of schematic knowledge about sources in source monitoring.

Source monitoring refers to mental processes leading to attributions regarding the origin of information. We tested Johnson, Hashtroudi, and Lindsay's (1993) assumption that prior source-relevant knowledge is used in some source-monitoring tasks. In two experiments using different domains of schematic knowledge, two sources presented information that was expected for one source and somewhat unexpected for the other. In a later source-monitoring test, participants decided whether items had been presented by Source A, by Source B, or were new. The results of both experiments show that source identification is better for expected items than for somewhat unexpected items. Multinomial modeling analyses revealed that when participants do not remember the source of information, they guess that it was presented by the expected source. These results provide evidence for the claim that source monitoring can be based on prior knowledge and support a guessing hypothesis.

Adolescent↗
PubMed2000

[Alien chromosomal identification in VE161 wheat].

VE161 wheat which has the function of promotting homoeologous pairing is a male sterile substitution line or a fertile addition line with one pair of alien chromosomes from Agropyron elongatum. The alien chromosome in VE161 wheat was detected by means of techniques of total genomic DNA in situ hybridization, RFLP and double-ditelo chromosomal analysis. The results from in situ hybridization confirmed that the alien chromosome was derived from Agropyron elongatum. The RFLP analysis showed that it belongs to fourth homoeologous group, and the results from double-ditelo chromosomal analysis gave evidence that 4B chromosome was replaced in the substitution line, so it can be concluded that, in VE161 wheat, the alien chromosome would be 4E and the replaced wheat chromosome would be 4B in the substitution line. The reason for the replaced chromosome identified as 7B in a earlier study might be due to the rearrangement occurred in the genome of wheat.

Chromosomes↗
PubMed1999

A survey of home nursing services in Taiwan.

This study investigated the current situation of home nursing services in Taiwan. A total of 93 home nursing agencies (response rate of 75%) responded to a mail survey. The majority of the agencies (63%) had been established within the last 3 years before the survey, were hospital-based (90%), and had less than 60 (89.3%) average total number of visits per month per nurse. Most of the home care nurses had taken home care nursing training courses and had at least 2 years of clinical experience. Half of the agencies provided care for patients on a respirator, and 28% provided in-home hospice care. Almost a third of the agencies performed poorly in the areas of supply management, supervision of home visits, and quality monitoring and improvement mechanisms. Several suggestions for the development of home nursing services in Taiwan are made.

Aged↗
PubMed1999

Corrected relationship between %dd(10)x and stopping-power ratios.

Kosunen and Rogers [Med. Phys. 20, 1181-1188 (1993)] presented a linear equation relating the Spencer-Attix water/air stopping power ratio to %dd(10)x, the photon component of the percentage depth-dose at 10 cm depth for a 10x10 cm2 field on the surface of a phantom at SSD=100 cm. This relationship has been used to calculate extensive tables of kQ factors for use with dosimetry protocols based on absorbed-dose calibration factors. Unfortunately, the original paper contained an error which has recently been assessed (Yang et al.). The present paper presents a corrected form of this relationship, viz.: (L/p)water(air)=1.275-0.00231[%dd(10)x] which is based on corrected values of %dd(10)x. It is shown that despite changes of up to 2% in calculated values of %dd(10)x, the net effect on calculated values of kQ is less than 0.2%.

Cobalt Radioisotopes↗