PubMed Health⌕ Search

Biomedical subjects

Wei Chen

Publications and source records attributed to Wei Chen.

At least 199 records · Page 11Linked to original sources
PubMed2005

First report of aphantoxins in China--waterblooms of toxigenic Aphanizomenon flos-aquae in Lake Dianchi.

The oligohaline cyanobacterium Aphanizomenon flos-aquae (L.) Ralfs (A. flos-aquae) has been reported in several countries to produce paralytic shellfish poisons (PSPs) or protracted toxic effects. In the past years, A. flos-aquae blooms have occurred annually in the eutrophic Lake Dianchi (300 km(2) in area, located in southwestern China). Material from natural blooms dominated by A. flos-aquae was collected and lyophilized. Acute toxicity testing was performed by mouse bioassay using extracts from the lyophilized material. Clear symptoms of PSPs intoxications were observed. To confirm the production of PSPs, a strain of A. flos-aquae (DC-1) was isolated and maintained in culture. Histopathological effects were studied by examining the organ damages using transmission electron microscopy (TEM). Slight hepatocytic damage with swollen mitochondria was found. The ultrastructural pulmonary lesions were characterized by distortied nuclei and indenting of karyotheca, together with degeneration and tumefaction of mitochondria and endoplasmic reticulum. Control animals injected with acetic acid did not exhibit histopathological damage in any organ. Toxic effects of cultured algal cells on enzymatic systems in the mouse were studied using sublethal doses of extracts. Significant glutathione-S-transferase (GST) and lactate dehydrogenase (LDH) increases, together with decrease of the glutathione (GSH) level, were measured. These results indicated a potential role of PSPs intoxicating and metabolizing in the test animals. HPLC-FLD and LC/MS analysis of extracts from cultured material demonstrated the PSP toxins produced by A. flos-aquae bloom. To the best of our knowledge, this is the first study reporting chemically and toxicologically confirmed PSP toxins related to A. flos-aquae in China.

Animals↗
PubMed2005

Acid fibroblast growth factor reduces rat intestinal mucosal damage caused by ischemia-reperfusion insult.

AIM: To detect the effects of acid fibroblast growth factor (aFGF) on apoptosis and proliferation of intestinal epithelial cells in differentiation or proliferation status to explore the protective mechanisms of aFGF. METHODS: Wistar rats were randomly divided into sham-operated control group (C, n=6), intestinal ischemia group (I, n=6), aFGF treatment group (A, n=48) and intestinal ischemia-reperfusion group (R, n=48). Apoptosis of intestinal mucosal cells was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) technique. Proliferating cell nuclear antigen (PCNA) protein expression and distribution were detected with immunohistochemical method. Plasma levels of D-lactate were determined with modified Brandts method. RESULTS: In A group, administration of exogenous aFGF could improve intestinal histological structure and decrease plasma D-lactate levels at 2-12 h after the reperfusion compared with R group. The apoptotic rates and PCNA protein expressions were not increased until 2 h after reperfusion and were maximal at 12 h. After reperfusion for 2-12 h, the apoptotic rates were gradually augmented along the length of jejunal crypt-villus units. Administration of aFGF could significantly reduce the apoptotic response at 2-12 h after reperfusion (P<0.05). Apoptosis rates in villus and crypt epithelial cells in A group at 12 h after reperfusion were (62.5+/-5.5)% and (73.2+/-18.6)% of those in R group, respectively. Treatment of aFGF could apparently induce protein expression of PCNA in intestinal mucosal cells of A group compared with R group during 2-12 h after reperfusion (P<0.05). There were approximately 1.3- and 1.5-times increments of PCNA expression levels in villus and crypt cells in A group at 12 h after reperfusion compared with R group, respectively. CONCLUSION: Intestinal I/R insult could lead to histological structure change and apoptotic rate increment. The protective effects of aFGF against ischemia/reperfusion in rat intestinal mucosa might be partially due to its ability to inhibit ischemia/reperfusion-induced apoptosis and to promote cell proliferation of crypt cells and villus epithelial cells.

Animals↗
PubMed2005

Li3-O-Li3 molecule: a metal-nonmetal-metal sandwichlike compound with a distending electron cloud.

The D3d and D2d isomers of the Li3-O-Li3 molecule are metal-nonmetal-metal sandwichlike structures that contain two Li3 superalkali atoms. Their geometries and the real frequencies are obtained at the CCSD(T)/aug-cc-pVDZ level. They are different from the traditional types of the nonmetal-metal-nonmetal sandwich compounds. The natural bond orbital calculation and the topological property nabla2rho(r) calculation indicate that they are typical ionic compounds. In two isomers, the O2- anion is sandwiched in between two Li3+ cation rings. However, the different orientations of two Li3+ planes give the D3d isomer its own special characteristics. Under the action of the O2- anion in the center, the valence electrons of the D3d isomer are pushed out from two Li3+ triangle rings. This special interaction causes three phenomena. First, the valence electron clouds are distended. Second, the vertical ionization energy of the D3d isomer is considerably low, 4.39 eV, so that it may also be viewed as a superalkali atom. Third, we find that the D3d isomer owns the out-of-plane aromaticity and the largest negative nucleus-independent chemical shift value (-10.8 ppm) exists at 2.5 A above the center of the Li3+ ring, not at the center of the Li3+ ring like the isolated aromatic Li3+ cation.

Journal Article↗
PubMed2005

The lysosome-associated apoptosis-inducing protein containing the pleckstrin homology (PH) and FYVE domains (LAPF), representative of a novel family of PH and FYVE domain-containing proteins, induces caspase-independent apoptosis via the lysosomal-mitochondrial pathway.

Lysosomes have recently been identified as important apoptotic signal integrators in response to various stimuli. Here we report the functional characterization of LAPF, a novel lysosome-associated apoptosis-inducing protein containing PH and FYVE domains. LAPF is a representative of a new protein family, the Phafins (protein containing both PH and FYVE domains), which consists of 14 unidentified proteins from various species. Overexpression of LAPF in L929 cells induces apoptosis and also increases cell sensitivity to TNFalpha-induced apoptosis, concomitant with its translocation to lysosomes. Two mutants of LAPF, either lacking the PH or FYVE domain, failed to induce cell death and translocate to lysosomes, suggesting that both domains are required for its apoptosis-inducing activity and relocation. We demonstrate that LAPF may induce apoptosis via the following steps: LAPF translocation to lysosomes, lysosomal membrane permeabilization (LMP), release of cathepsin (cath) D and L, mitochondrial membrane permeabilization (MMP), release of apoptosis-inducing factor (AIF), and caspase-independent apoptosis. The cath D-specific inhibitor attenuates LAPF-induced apoptosis, indicating a pivotal role of lysosomes in LAPF-initiated apoptosis. We also demonstrate that the lysosomal pathway was employed in the typical apoptotic model in which high dose TNFalpha was used to stimulate L929 cells. Silencing of LAPF expression by small RNA interference protected L929 cells from hTNFalpha-induced apoptosis by impairing hTNFalpha-triggered LMP and MMP. Therefore, LAPF may launch caspase-independent apoptosis through the lysosomal-mitochondrial pathway.

Amino Acid Sequence↗
PubMed2005

New observations on the luminescence decay lifetime of Mn2+ in Zns: Mn2+ nanoparticles.

A fast decay emission peaking at 645 nm with a decay lifetime within the experimental resolution of 0.14 micros is observed in ZnS:Mn2+ nanoparticles. This short-lived signal is also observed in pure ZnS and MgS: Eu3+ nanoparticles, which has nothing to do with Mn(2+)-doped ions but is from the deep trap states of the host materials. The short-lived component decreases in intensity relative to the Mn2+ emission at higher excitation powers, while it increases in intensity at low temperatures and shifts to longer wavelengths at longer time delays. Our observations demonstrated further that the emission of Mn2+ in ZnS: Mn2+ nanoparticles behaves basically the same as in bulk ZnS: Mn2+; the fast decay component is actually from the intrinsic and defect-related emission in sulfide compounds.

Chemistry, Physical↗
PubMed2005

Impedance labelless detection-based polypyrrole protein biosensor.

A simple and sensitive electrochemical immunosensor with impedance labelless detection and novel data processing method was investigated. One-step copolymerization was used to electrochemically deposit an antibody impregnated polypyrrole film on a glassy carbon electrode surface for the immunosensor. Impedance measurements provided a labelless or reporterless method to detect antibody (Ab)-antigen (Ag) interactions. Dimensionless analysis was employed to successfully process the measured impedance data. Since the method derived unit impedance change to eliminate or reduce the variation of the bulk electronic properties of Ab/polypyrrole films, the signal to noise ratio (S/N) was significantly improved for high sensitivity and specificity. Nonspecific binding effect was studied by array electrode chips and was found out that the polypyrrole electrode without antibody attachment had much stronger nonspecific binding effect than the Ab/polypyrrole electrode; incubation followed by thoroughly washing significantly reduced the nonspecific interference. 10 pg/ml detection limit and superior specificity were achieved by the method, demonstrating a highly sensitive labelless immunosensor in comparison with the detection limit of ng -microgram/ml for the reported polypyrrole based immunosensors. The electrochemical immunosensors presented in this paper, due to its simplicity, low cost, high sensitivity and superior specificity, could be an invaluable tool for clinical diagnostics and could have potential applications in drug discovery, environmental and food analysis.

Antibodies↗
PubMed2005

[Prospective comparison of functional magnetic resonance imaging and intraoperative motor evoked potential monitoring for cortical mapping of primary motor areas].

OBJECTIVE: To compare the relation between the preoperative functional magnetic resonance imaging (fMRI) with blood oxygen level dependent (BOLD) technique and intraoperative motor evoked potential (MEP) monitoring for cortical mapping of primary motor cortex in patients with tumors near the central area. And to determine whether non-invasive preoperative fMRI can provide results equivalent to those achieved with the invasive neurosurgical "gold standard". METHODS: A prospective study of 16 patients with various pathological tumors of the central area was conducted. Preoperative fMRI scans using the BOLD contrast technique in each patient were performed. An activation scan was achieved by using a motor task paradigm, which consisted of simple flexion-extension finger movements and finger-to-thumb touching in a repeating pattern. The anatomical structure was delineated by the T(1)-weighted three-dimensional fast spoiled gradient recalled sequence (3D/FSPGR) immediately afterward. The BOLD images were overlaid on the T(1)-weighted 3D/FSPGR images, and then co-registered to the neuronavigation system. The fMRI activations were documented by using a neuronavigation system in sequence, and compared to standardized intraoperative MEP monitoring, which included direct cortical electrical stimulation (DCES) or transcranial cortical electrical stimulation (TCES) or their combination. The compound muscle action potentials of forearm flexor and hand muscle responses were recorded during either TCES or DCES. Two techniques were compared to determine the accuracy for cortical mapping of primary motor areas with fMRI. RESULTS: Overall, the intraoperative MEP monitoring showed good correlation with fMRI activation in 92.3% of cases. The coincidence rate, however, was 100.0% between TCES and fMRI, and 66.7% between DCES and fMRI respectively. There was no statistically difference between two cortical mapping techniques, chi-square test of paired comparison of enumeration data, P < 0.01. CONCLUSION: BOLD fMRI was a high sensitive and reliable technique to locate the position of the primary motor areas and their spatial relation with adjacent tumor, especially for the presurgical planning in patients with central area brain tumor.

Adolescent↗
PubMed2005

Genetic stability determinants of temperature sensitive, live attenuated respiratory syncytial virus vaccine candidates.

An intranasally delivered, live attenuated, temperature sensitive (ts) respiratory syncytial virus vaccine candidate, rA2cp248/404/1,030DeltaSH, exhibits a low level of genetic instability in clinical studies, in contrast to the relatively high stability of two similar candidates, cpts248/404 and rA2cp248/404DeltaSH. The latter strains, containing two ts mutations (248ts and 404ts), are partially growth restricted at 37 degrees C, whereas, rA2cp248/404/1,030DeltaSH contains an additional ts mutation (1,030ts) that increases attenuation and partially restricts virus growth at 35 degrees C. Since the maximum human airway temperature is 35.5 degrees C, we investigated whether growth restriction at 35 degrees C contributes to genetic instability of rA2cp248/404/1,030DeltaSH in vitro. We conducted in vitro passage studies with the three strains at 32 degrees C (a fully permissive growth temperature) and 35 degrees C (restrictive for only rA2cp248/404/1,030DeltaSH). Instability of the ts phenotype was observed only in rA2cp248/404/1,030DeltaSH passaged at 35 degrees C, and corresponded with reversion at the 248ts or 1,030ts mutation sites, as observed in clinical studies. This study indicates that ts mutations that partially restrict replication at physiologic temperatures may contribute to genetic instability of viruses in vivo. In vitro passage studies performed at appropriate temperatures can be used to assess genetic stability and to prioritize ts vaccine candidates for clinical evaluation.

Administration, Intranasal↗
PubMed2005

The structure and the large nonlinear optical properties of Li@calix[4]pyrrole.

A new compound with electride characteristics, Li@calix[4]pyrrole, is designed in theory. The Li atom in Li@calix[4]pyrrole is ionized to form a cation and an excess electron anion. Its structure with C(4v) symmetry resembles a cup-like shape. It may be a stable organic electride at room temperature. The first hyperpolarizability of the cup-like electride molecule is first investigated by the DFT (B3LYP) method. The result shows that this electride molecule has a considerably large first hyperpolarizability with beta(0) = 7326 au (63.3 x 10(-30) esu), while the beta(0) value of the related calix[4]pyrrole system is only 390 au. Obviously, the Li atom doped in calix[4]pyrrole brings a dramatic change to the electronic structure, so that the first hyperpolarizability of Li@calix[4]pyrrole is almost 20 times larger than that of calix[4]pyrrole. We find that the excess electron from the Li atom plays an important role in the large first hyperpolarizability of Li@calix[4]pyrrole. The present investigation reveals a new idea and different means for designing and synthesizing high-performance NLO materials.

Journal Article↗
PubMed2005

Virus overrides the propensity of human CD40L-activated plasmacytoid dendritic cells to produce Th2 mediators through synergistic induction of IFN-{gamma} and Th1 chemokine production.

Depending on the activation status, plasmacytoid dendritic cells (PDC) and myeloid DC have the ability to induce CD4 T cell development toward T helper cell type 1 (Th1) or Th2 pathways. Thus, we tested whether different activation signals could also have an impact on the profile of chemokines produced by human PDC. Signals that induce human PDC to promote a type 1 response (i.e., viruses) and a type 2 response [i.e., CD40 ligand (CD40L)] also induced PDC isolated from tonsils to secrete chemokines preferentially attracting Th1 cells [such as interferon-gamma (IFN-gamma)-inducible protein (IP)-10/CXC chemokine ligand 10 (CXCL10) and macrophage inflammatory protein-1beta/CC chemokine ligand 4 (CCL4)] or Th2 cells (such as thymus and activation-regulated chemokine/CCL17 and monocyte-derived chemokine/CCL22), respectively. Activated natural killer cells were preferentially recruited by supernatants of virus-activated PDC, and supernatants of CD40L-activated PDC attracted memory CD4(+) T cells, particularly the CD4(+)CD45RO(+)CD25(+) T cells described for their regulatory activities. It is striking that CD40L and virus synergized to trigger the production of IFN-gamma by PDC, which induces another Th1-attracting chemokine monokine-induced by IFN-gamma/CXCL9 and cooperates with endogenous type I IFN for IP-10/CXCL10 production. In conclusion, our studies reveal that PDC participate in the selective recruitment of effector cells of innate and adaptive immune responses and that virus converts the CD40L-induced Th2 chemokine patterns of PDC into a potent Th1 mediator profile through an autocrine loop of IFN-gamma.

Autocrine Communication↗
PubMed2005

Increased subclinical atherosclerosis in young adults with metabolic syndrome: the Bogalusa Heart Study.

OBJECTIVES: The purpose of this study was to investigate the association of metabolic syndrome (MetS) with subclinical atherosclerosis, determined by ultrasound carotid intima-media thickness (CIMT) measurements, in young adults. BACKGROUND: Metabolic syndrome is associated with subclinical atherosclerosis and increased cardiovascular risk in older and middle-aged adults; however, these associations have not been studied among young adults. METHODS: Non-diabetic subjects from Bogalusa Heart Study, a longitudinal study of atherosclerosis in young adults, underwent B-mode ultrasonography of the carotid arteries. Metabolic syndrome was defined with the National Cholesterol Education Program Adult Treatment Panel III (MetSNCEP) and World Health Organization (MetSWHO) definitions. CIMT and MetS associations were evaluated with multivariable regression and area under receiver-operator characteristic curve (AUC) analyses. RESULTS: Of 507 subjects (29% black, 39% male, mean [SD] age 32 [3] years), 67 (13%) had MetSNCEP and 65 (13%) had MetSWHO. Common (mean = 0.70 [0.11] mm vs. 0.66 [0.08] mm, p = 0.002) and internal CIMT (0.72 [0.21] mm vs. 0.68 [0.12] mm, p = 0.020) were higher among those with MetS(NCEP) than those without MetS(NCEP). Common (0.69 [0.11] mm vs. 0.66 [0.08] mm, p = 0.020) and internal CIMT (0.73 [0.23] mm vs. 0.68 [0.12] mm, p = 0.012) also were higher among those with MetSWHO than those without MetSWHO. Composite CIMT increased with the number of MetS components present (MetSNCEP r = 0.997, p < 0.001; MetSWHO r = 0.946, p = 0.053). Metabolic syndromeNCEP (AUC = 0.557, 95% confidence interval [CI] 0.513 to 0.601) and MetSWHO (AUC = 0.539, 95% CI 0.495 to 0.584) both predicted composite CIMT > or =75th percentile. CONCLUSIONS: In young adults, MetS is associated with increased atherosclerotic burden, and therefore, increased cardiovascular risk. These results support the importance of screening and early intervention in this population.

Adult↗
PubMed2005

[Cellular phenotype conversion induced by co-culture of human mesenchymal stem cells cocultured with human sweat gland cells].

OBJECTIVE: To investigate the cellular phenotype conversion during human mesenchymal stem cells (hMSCs) cocultured with injured human sweat gland cells (hSGCs) in vitro. METHODS: HMSCs and hSGCs were isolated and cultured and expanded respectively. The antigens expression of hMSCs and hSGCs were detected by two-steps immunocytochemistry. HMSCs were labeled with BrdU. The hSGCs were heat-shocked at 47 degrees C for 40 min when they reached 70% confluency, then cooled for 1-2 h at 37 degrees C and (1 - 2) x 10(5) BrdU-labeled hMSCs were added before incubation for up to 2 weeks. The cocultures were observed by phase contrast microscopy and detected by double-staining immunocytochemistry using CEA and BrdU as primary antibodies. RESULTS: The cultured hMSCs and hSGCs were clonogenic growth. HMSCs were positive for anti-CD44 and anti-CD105 staining and negative for anti-CD34 and anti-CEA staining. HSGCs express CK7, CK18, CK19 and CEA. The positive rate of BrdU labeled-hMSCs was 90%. The majority of hSGCs lost cell-cell contact after heat-shock. 2 weeks after cocultured, some cocultured cells were positive for both anti-CEA and anti-BrdU staining and some cocultures had more than two nuclei which stained with two different colors by double-staining immunocytochemistry. Statistic results showed 1%-5% of the hMSCs added to the coculture system were recovered as double-staining cells expressing BrdU and CEA while only 0.01%-0.05% cells stained with two different colors in nuclei. The multi-nucleated cells were wide and flatten. CONCLUSION: HMSCs could differentiate into hSGCs in vitro under injured microenvironment. The mechanisms of which may be that hMSCs differentiate into hSGCs directly or by cell fusion, even nucleus fusion.

Bone Marrow Cells↗
PubMed2005

MED1/TRAP220 exists predominantly in a TRAP/ Mediator subpopulation enriched in RNA polymerase II and is required for ER-mediated transcription.

Human TRAP/Mediator is a key coactivator for many transcription factors that act through direct interactions with distinct subunits, and MED1/TRAP220 is the main subunit target for various nuclear receptors. Remarkably, the current study shows that MED1/TRAP220 only exists in a TRAP/Mediator subpopulation (less then 20% of the total) that is greatly enriched in specific TRAP/Mediator subunits and is tightly associated with a near stoichiometeric level of RNA polymerase II. Importantly, this MED1/TRAP220-containing holoenzyme supports both basal- and activator-dependent transcription in an in vitro system lacking additional RNA polymerase II. Furthermore, chromatin immunoprecipitation experiments demonstrate an activator-selective recruitment of MED1/TRAP220-containing versus MED1/TRAP220-deficient TRAP/Mediator complexes to estrogen receptor (ER) and p53 target genes, respectively. Finally, RNAi studies show that MED1/TRAP220 is required for ER-mediated transcription and estrogen-dependent breast cancer cell growth. These observations have significant implications for our current understanding of the composition, heterogeneity, and functional specificity of TRAP/Mediator complexes.

Breast Neoplasms↗
PubMed2005

Gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor and human epidermal growth factor receptors in human corpus luteum.

BACKGROUND: The objective of this study was to elucidate gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and human epidermal growth factor receptor (HER) family in the human ovary during luteal growth and regression. METHODS: Ovaries obtained from pre-menopausal women were used for immunohistochemistry and semiquantitative RT-PCR analysis. RESULTS: Immunoreactive HB-EGF was not detected in follicles or oocyte, while HB-EGF became apparent in granulosa luteal cells in the early luteal phase, and most abundant in the mid-luteal phase, but less abundant in the late luteal phase. Immunostaining for HER1 was very weak in granulosa luteal cells in the early and mid-luteal phases, and was not detected in the late luteal phase. Immunoreactive HER4 was abundant in the early luteal phase and became less abundant in the mid-luteal phase, whereas it was negative in the late luteal phase. Semiquantitative RT-PCR analysis revealed that HB-EGF and HER1 mRNA levels were high in the mid-luteal phase, whereas HER4 mRNA expression was high in the early luteal phase. CONCLUSIONS: HB-EGF may play a vital role in regulating luteal growth in a juxtacrine manner and through activating HER4 signalling.

Adult↗
PubMed2005

[Effects of schisandrin B on reversing multidrug resistance in human breast cancer cells transfected with mdr1 gene].

OBJECTIVE: To investigate the multidrug resistance (MDR) reversal activity of schisandrin B (SchB) in transfected human breast cancer cell line MCF-7/MDR1. METHODS: Human breast cancer cells of the line MCF-7 were cultured and transfected with mdr1 gene so as to establish a P-glycoprotein (P-gp) stable-expressing cell line MCF-7/MDR1. The expression of P-gp in the MCF-7/mdr1 cells was assayed by flow cytometry using fluorescent antibody. MCF-7 cells transfected with blank plasmid MCF-7/neo was used as controls. Adriamycin (ADR), verapamil (VER), pacilitaxel (taxol), and homoharringtonine (HHT) were added into the culture fluid of the MCF-7/mdr1 cells and MTT method was used to detect the IC(50) of these drugs. The culture fluid of the MCF-7/MDR1 cells was added with SchB of the concentrations of 2.5, 12.5, 25, and 50 micromol/L and then added with ADR1 cells, MTT method was used to calculate the reversal effect (RF) of SchB on the MDR phenotype of the MCF-7/mdr1 cells. MTT method was used to calculate the RF. Another culture fluid of MCF-7/mdr1 cells was added with 25 micromol/L SchB and then with ADR, vincristine (VCR), pacilitaxel, and HHT with that added with 10 micromol/L VER as control. After treatment with SchB the MF7/mgr1 cells were co-incubated with 5 micromol/L rhodamine (Rh)-123, then flow cytometry was used to detect the accumulation of Rh-123 within the cells. After treatment with 25 micromol/L SchB for 0, 0.5, 1, 6, 24, 48, and 72 hours flow cytometry was used to detect the P-gp expression in the MF7/mgr1 cells. RESULTS: The transfected MCF-7/MDR1 cells overexpressed P-gp and exhibited resistance to multiple drugs, including ADR, VCR, pacilitaxel and HHT. SchB (25 micromol/L) significantly enhanced the sensitivity of the MCF-7/MDR1 cells to above mentioned chemotherapeutic agents, with a reversal factors of 6.03 to 23.94 times. The effect of SchB (25 micromol/L) on Rh-123 accumulation in MDR cells was equivalent to that of 10 micromol/L VER, however no significant difference was found in the effect of SchB (25 micromol/L) on the P-gp expression in the MCF-7/MDR1 cells. CONCLUSION: SchB is able to restore the drug sensitivity in the transfected MCF7/MDR1 cells, with a possible mechanism of increasing the drug influx via inhibiting the P-gp function.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Procedure for minimizing stress for fMRI studies in conscious rats.

Functional magnetic resonance imaging (fMRI) in conscious animals is evolving as a critical tool for neuroscientists. The present study explored the effectiveness of an acclimation procedure in minimizing the stress experienced by the animal as assessed by alterations in physiological parameters including heart rate, respiratory rate, and serum corticosterone levels. Results confirm that as the stress of the protocol is minimized, there is a significant decrease in head movements and enhancement in data quality. The feasibility of improving the quality of fMRI data acquired in alert rats by utilizing a relatively simple technique is presented.

Acclimatization↗
PubMed2005

X-Ray storage luminescence of BaFCl:Eu2+ single crystals.

Temperature behaviors of X-ray luminescence (XL), photoluminescence (PL), photostimulated luminescence, and thermoluminescence (TL) were studied in BaFCl:Eu2+ single crystals from room temperature to liquid nitrogen temperature. Six emissions at 275, 315, 365, 385, 435, and 500 nm were observed in the XL spectra and are attributed to Cl excitons, V(k)(Cl2-), the 4f65d1 (2e(g)) --> 4f7 (8S(7/2)) transition of Eu2+, and oxygen vacancies, respectively. Three emission peaks at 315, 365, and 390 nm were observed in the PL and TL measurements. These three emissions are from the transitions of 4f7(6I(7/2)) --> 4f7(8S(7/2)), 4f7(6P(7/2)) --> 4f7(8S(7/2)), and 4f65d1 (2e(g)) --> 4f7(8S(7/2)) of Eu2+, respectively. In our measurements, we observed that the emission of Eu2+ increases in intensity upon beta-irradiation and did not see any signals related to Eu3+ ions, which indicates that Eu2+ ions might not be oxidized to Eu3+ upon X-ray or beta-irradiation. Instead, the color centers, Cl excitons, and oxygen defects are created and are stable at room temperature, and they might play a key role in the storage luminescence.

Barium Compounds↗