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Yi-Ping Wang

Publications and source records attributed to Yi-Ping Wang.

At least 19 recordsLinked to original sources
PubMed2006

Highly sensitive long-period fiber-grating strain sensor with low temperature sensitivity.

A long-period fiber-grating sensor with a high strain sensitivity of -7.6 pm/microepsilon and a low temperature sensitivity of 3.91 pm/ degrees C is fabricated by use of focused CO(2) laser beam to carve periodic grooves on a large- mode-area photonic crystal fiber. Such a strain sensor can effectively reduce the cross-sensitivity between strain and temperature, and the temperature-induced strain error obtained is only 0.5 microepsilon/ degrees C without using temperature compensation.

Journal Article↗
PubMed2006

Laser Doppler flowmetry for assessment of myocardial microperfusion in the beating rat heart.

Although laser Doppler flowmetry (LDF) is widely used for measuring microperfusion, it is rarely used to measure coronary microcirculation. The present in vivo study investigated the use of LDF to measure myocardial microperfusion in beating rat hearts. Ascending aortic flow and other hemodynamic parameters were simultaneously recorded. A needle probe with a holder was adhered to the epicardium of the left ventricular myocardium close to the left anterior descending coronary artery in an anaesthetized open-chest rat. Myocardial microperfusion was measured in response to bolus intravenous administration of both two representative vasodilators (captopril and nifedipine) and a vasoconstrictor (pituitrin). Myocardial microperfusion was found to be predominately diastolic, and in an opposing phase to the ascending aortic flow. Captopril (5 or 10 mg/kg) increased the initial myocardial microperfusion phase. Nifedipine at 75 microg/kg caused a sustained myocardial microperfusion elevation with a peak increase of 7.1+/-1.1%, but this was not observed using 150 microg/kg nifedipine. Both drugs caused an increase in the cardiac index. In contrast, myocardial microperfusion decreased (28.7+/-0.1% maximum decrease) in response to 1 IU/kg pituitrin. In conclusion, LDF provided a means of assessing myocardial microperfusion in beating rat hearts, and can be applied to evaluate the coronary microcirculation response to drugs.

Animals↗
PubMed2006

CO2 laser-grooved long period fiber grating temperature sensor system based on intensity modulation.

A long period fiber grating (LPFG) temperature sensor system based on intensity modulation is developed. The LPFG employed is fabricated by the use of a focused CO2 laser beam to carve periodic grooves on the fiber. The temperature measurement resolution of up to 0.1 degrees C has been obtained within the temperature range between 20 degrees C and 100 degrees C. The system uses a simple intensity measurement method and exhibits the advantages of convenient intensity measurement, double temperature sensitivity, high resolution, simple configuration, and low cost.

Journal Article↗
PubMed2006

Measuring optical fiber length by use of a short-pulse optical fiber ring laser in a self-injection seeding scheme.

A method for measuring the length of an optical fiber by use of an optical fiber ring laser pulse source is proposed and demonstrated. The key element of the optical fiber ring laser is a gain-switched Fabry-Perot laser diode operated in a self-injection seeding scheme. This method is especially suitable for measuring a medium or long fiber, and a resolution of 0.1 m is experimentally achieved. The measurement is implemented by accurately determining the pulse frequency that can maximize the output power of the fiber ring laser. The measurement results depend only on the refractive index of the fiber corresponding to this single wavelength, instead of the group index of the fiber, which represents a great advantage over both optical time-domain reflectometry and optical low-coherence reflectometry methods.

Journal Article↗
PubMed2006

Expression of human telomerase reverse transcriptase (hTERT) protein is significantly associated with the progression, recurrence and prognosis of oral squamous cell carcinoma in Taiwan.

This study used an immunohistochemical technique to examine the expression of human telomerase reverse transcriptase (hTERT) protein in 82 specimens of OSCC, 116 specimens of oral epithelial dysplasia (OED), and 21 specimens of normal oral mucosa (NOM). The cytoplasmic and nuclear hTERT staining intensity (SI; 0, no staining; 1, weak; 2, moderate; 3, strong), labeling indices (LIs, defined as the percentage of positive cells in total cells), and labeling scores (LSs, defined as LI x SI) in OSCC, OED, and NOM samples were calculated and compared among groups. The correlation between the cytoplasmic or nuclear hTERT LS in OSCCs and clinicopathological parameters or survival of OSCC patients was analyzed statistically. The mean cytoplasmic hTERT LSs increased significantly from NOM (87+/-17%) through OED (95+/-18%) to OSCC samples (114+/-33%, p=0.000). The mean nuclear hTERT LSs also increased from NOM (80+/-14%) to OED (91+/-20%) and then decreased to OSCC samples (86+/-35%) with no statistically significant difference among the 3 groups. A significant correlation was found between the higher mean cytoplasmic hTERT LSs and OSCCs occurring in male patients (p=0.023), with larger tumor sizes (T3 and T4, p=0.048), with more advanced clinical stages (stages 3 and 4, p=0.033), or from patients with areca quid chewing (p= 0.029), cigarette smoking (p=0.027), or alcohol drinking habit (p=0.025). In addition, OSCC patients with nuclear hTERT LSs greater than 100% were prone to have a higher recurrence rate (p=0.044) and a lower 5-year survival rate (p=0.011). Our results indicate that the increased expression of hTERT protein is an early event in oral carcinogenesis and hTERT may be a biomarker for OSCCs. Measuring the amount of cytoplasmic or nuclear expression of hTERT in OSCC samples may predict the oral cancer progression, recurrence, and prognosis in Taiwan.

Adult↗
PubMed2006

Reconstitution of the enzyme AroA and its glyphosate tolerance by fragment complementation.

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase (AroA) is a key enzyme in the aromatic amino acid biosynthetic pathway in microorganisms and plants, and is the target of the herbicide glyphosate. Glyphosate tolerance activity of the enzyme could be obtained by natural occurrence or by site-directed mutagenesis. A functional Pseudomonas putida AroA was obtained by co-expression of two protein fragments AroA(P. putida)-N210 and AroA(P. putida)-C212 in Escherichia coli aroA mutant strain AB2829. From sequence analysis, the equivalent split site on E. coli AroA was chosen for further study. The result indicated that functional E. coli AroA could also be reconstituted from two protein fragments AroA(E. coli)-N218 and AroA(E. coli)-C219, under both in vivo and in vitro conditions. This result suggested that the fragment complementation property of this family of enzyme may be general. Additional experiments indicated that the glyphosate tolerance property of AroA could also be reconstituted in parallel with its enzyme activity. The implication of this finding is discussed.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed2006

Protein-induced DNA bending clarifies the architectural organization of the sigma54-dependent glnAp2 promoter.

Sigma54-RNA polymerase (Esigma54) predominantly contacts one face of the DNA helix in the closed promoter complex, and interacts with the upstream enhancer-bound activator via DNA looping. Up to date, the precise face of Esigma54 that contacts the activator to convert the closed complex to an open one remains unclear. By introducing protein-induced DNA bends at precise locations between upstream enhancer sequences and the core promoter of the sigma54-dependent glnAp2 promoter without changing the distance in-between, we observed a strong enhanced or decreased promoter activity, especially on linear DNA templates in vitro. The relative positioning and orientations of Esigma54, DNA bending protein and enhancer-bound activator on linear DNA were determined by in vitro footprinting analysis. Intriguingly, the locations from which the DNA bending protein exerted its optimal stimulatory effects were all found on the opposite face of the DNA helix compared with the DNA bound Esigma54 in the closed complex. Therefore, these results provide evidence that the activator must approach the Esigma54 closed complexes from the unbound face of the promoter DNA helix to catalyse open complex formation. This proposal is further supported by the modelling of activator-promoter DNA-Esigma54 complex.

Base Sequence↗
PubMed2006

FIS activates glnAp2 in Escherichia coli: role of a DNA bend centered at -55, upstream of the transcription start site.

A binding site for the Escherichia coli nucleoid binding protein FIS (factor for inversion stimulation) was identified upstream of a sigma54-dependent promoter, glnAp2. The binding and bending center of FIS is positioned at -55 with respect to the transcription start site (+1). Binding of FIS at this site activates the transcription of glnAp2 both in vivo and in vitro. Furthermore, we substituted the FIS-mediated DNA bending with other protein (cAMP receptor protein or integration host factor)-mediated DNA bending, without changing the position of the bending center. In vitro transcription assays indicated that all DNA bends centered at -55 activate transcriptional initiation of glnAp2, especially when linear templates were used.

Base Sequence↗
PubMed2006

Expression and purification of lipoprotein-associated phospholipase A(2), a key enzyme involved in atherosclerosis.

AIM: To express and purify lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), and to establish a screening model for Lp-PL A(2) inhibitors using the expressed Lp-PLA(2). METHODS: We cloned the full-length cDNA of Lp-PLA(2) from differentiated THP-1 cells, and subcloned the cDNA into the baculovirus transfer vector pFastBac1. In addition, we introduced an N-terminal Kozak sequence for high-level translation initiation and a C-terminal sequence of 6 histidine residues for purification. The fusion enzyme was expressed in Sf9 insect cells and purified by Ni(2+) affinity chromatography. Recombinant Lp-PLA(2) activity was measured using [(3)H]PAF as a substrate, and we examined the enzyme activity of recombinant Lp-PLA(2) pretreated with the known Lp-PLA(2) inhibitor SB435495. RESULTS: We successfully cloned the full-length Lp-PLA(2) gene from differentiated THP-1 cells. The fusion enzyme was expressed in Sf9 insect cells at a high level and purified efficiently through a 2-step procedure. The recombinant Lp-PLA(2) activity was measured using [(3)H]PAF as a substrate, and proved to be enzymatically active. Lp-PLA(2) inhibitor SB435495 produced a good inhibition curve for inhibition of recombinant Lp-PLA(2) with an IC(50) of 57+/-1 micromol/L. CONCLUSION: We expressed and purified Lp-PLA(2) at a high level in insect cell-baculovirus expression system. The yield ratio was much greater than that obtained from human plasma and we established a screening model for Lp-PL A(2) inhibitors using the expressed Lp-PLA(2).

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2005

Selective modulation of L-type calcium current by magnesium lithospermate B in guinea-pig ventricular myocytes.

Magnesium lithospermate B (MLB) is the main water-soluble principle of Salviae Miltiorrhizae Radix (also called as 'Danshen' in the traditional Chinese medicine) for the treatment of cardiovascular diseases. MLB was found to possess a variety of pharmacological actions. However, it is unclear whether and how MLB affects the cardiac ion channels. In the present study, the effects of MLB on the voltage-activated ionic currents were investigated in single ventricular myocytes of adult guinea pigs. MLB reversibly inhibited L-type Ca(2+) current (I(Ca,L)). The inhibition was use-dependent and voltage-dependent (the IC(50) value of MLB was 30 microM and 393 microM, respectively, at the holding potential of -50 mV and -100 mV). In the presence of 100 microM MLB, both the activation and steady-state inactivation curves of I(Ca,L) were markedly shifted to hyperpolarizing membrane potentials, whereas the time course of recovery of I(Ca,L) from inactivation was not altered. MLB up to 300 microM had no significant effect on the fast-inactivating Na(+) current (I(Na)), delayed rectifier K(+) current (I(K)) and inward rectifier K(+) current (I(K1)). The results suggest that the voltage-dependent Ca(2+) antagonistic effect of MLB work in concert with its antioxidant action for attenuating heart ischemic injury.

Animals↗
PubMed2005

Electro-optic polymer waveguide grating with fast tuning capability.

A novel fast tunable electro-optic (EO) polymer waveguide grating is proposed and designed. Its resonant wavelength can be linearly tuned via the first-order EO effect with a high sensitivity of 6.1 pm/V. We find that the spectrum characteristics of EO polymer waveguide gratings depend strongly on many grating parameters, such as refractive-index modulation, modulation function, grating period, and period number. Material selection, fabrication technology, EO tuning ability, and polarization dependence of EO polymer waveguide gratings are also discussed. Such a waveguide grating not only overcomes the disadvantages of fiber-optic gratings, such as slow wavelength tuning ability and large-scale integration inconvenience, but also has many advantages, such as high resonant-wavelength tuning sensitivity, the same fabrication technology used for semiconductors, and polarization independence.

Journal Article↗
PubMed2005

Successful treatment of an extensive verrucous carcinoma with topical 5-aminolevulinic acid-mediated photodynamic therapy.

Our recent study found that a new topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) protocol composed of multiple 3-min fractionated irradiations with a light emitting diode (LED) red light at 635 +/- 5 nm for a total of 1000 s (fluence rate: 100 mW/cm(2); light exposure dose: 100 J/cm(2)) after topical application of 20% ALA for 1.5 or 2 h can be used successfully for the treatment of oral verrucous hyperplasia. In this case report, we tested the efficacy of this new treatment protocol of ALA-PDT for an extraoral verrucous carcinoma (VC) lesion at the right mouth angle and an intraoral VC lesion at the right buccal mucosa of a 56-year-old male areca quid chewer and smoker. The extraoral tumor was cleared after six treatments of topical ALA-PDT and the intraoral tumor showed complete regression after 22 treatments of topical ALA-PDT. No recurrence of the VC lesion was found after a follow-up period of 6 months. We suggest that PDT using a topical application of 20% ALA followed by multiple 3-min fractionated irradiations with an LED red light is also an effective and successful treatment modality for VC.

Administration, Topical↗
PubMed2005

HMB-45 may be a more sensitive maker than S-100 or Melan-A for immunohistochemical diagnosis of primary oral and nasal mucosal melanomas.

BACKGROUND: Primary mucosal melanomas (MMs) of the head and neck are a rare entity. Melanomas with characteristic melanin-pigmented tumor cells are easy to diagnose, but those without melanin-pigmented tumor cells, amelanotic melanomas, are difficult to identify and need immunohistochemistry (IHC) to confirm the final diagnosis. In this study, we examined the expression of three melanocytic differentiation markers, HMB-45, S-100, and Melan-A in primary oral and nasal MMs. We tried to evaluate whether HMB-45, S-100, and Melan-A were useful for diagnosis of primary oral and nasal MMs and to find out which marker was the best of the three. METHODS: This study used IHC to examine the expression of HMB-45, S-100, and Melan-A in 17 formalin-fixed paraffin-embedded specimens of primary oral and nasal MMs. The staining intensities (SIs) and labeling indices (LIs) of HMB-45, S-100, and Melan-A in 17 MMs were calculated and compared between any two markers. RESULTS: Immunostaining results showed that the positive rate was 94% (16 of 17) for HMB-45, 88% (15 of 17) for S-100, and 71% (12 of 17) for Melan-A in 17 MMs. The SI of HMB-45 was significantly higher than that of S-100 (P = 0.0011) or of Melan-A (P = 0.0034). In addition, the mean LI of Melan-A (59 +/- 43%) was significantly lower than that of HMB-45 (83 +/- 28%, P = 0.0065) or of S-100 (79 +/- 33%, P = 0.0237). CONCLUSIONS: Our results indicate that both HMB-45 and S-100 show a high positive rate and LI in MMs and therefore may be good markers for immunohistochemical diagnosis of primary oral and nasal MMs. In addition, HMB-45 may be a more sensitive marker than S-100 because HMB-45 shows a significantly higher SI than S-100 in this study.

Adult↗
PubMed2005

Novel AroA with high tolerance to glyphosate, encoded by a gene of Pseudomonas putida 4G-1 isolated from an extremely polluted environment in China.

Glyphosate has been used globally as a safe herbicide for weed control. It inhibits 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase (AroA), which is a key enzyme in the aromatic amino acid biosynthetic pathway in microorganisms and plants. A Pseudomonas putida strain, 4G-1, was isolated from a soil heavily contaminated by glyphosate in China. Its AroA-encoding gene (aroA) has been cloned, sequenced, and expressed in Escherichia coli. Phylogenetic analysis revealed that this AroA belongs neither to class I nor to class II AroA enzymes. When compared with E. coli AroA, 4G-1 AroA shows similar values for K(m)[PEP], K(m)[S3P], and specific enzyme activity. Moreover, 4G-1 AroA exhibits high tolerance to glyphosate, which indicates a protein with a high potential for structural and functional studies of AroA in general and its potential usage for the generation of transgenic crops resistant to the herbicide.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed2004

Synthesis of novel chiral and acentric coordination polymers by the reaction of zinc or cadmium salts with racemic 3-pyridyl-3-aminopropionic acid.

Under hydrothermal (solvothermal) reaction conditions chiral compounds 1, 2, and 3 and one acentric compound 4 were obtained by the reaction of Zn(2+) or Cd(2+) with racemic 3-(3-pyridyl)-3-aminopropionic acid (rac-HPAPA). Compounds 1 and 2 crystallized in chiral space group P2(1)2(1)2(1). At 105 degrees C, racemic 3-pyridyl-3-aminopropionic acid (rac-HPAPA) reacted with Zn(ClO4)(2).6 H2O and dehydrogenated in situ to form the first chiral coordination polymer [Zn[(E)-3-C(5)H4N-C(NH2)=CH-COO]]ClO4 (1) with a beta-dehydroamino acid. Beyond 120 degrees C, the reaction of rac-HPAPA with Zn(ClO4)(2).6 H2O deaminates in situ to form chiral coordination polymer [Zn[(E)-3-C5H4N-CH=CH-COO](OH)] (2). At relatively low temperatures (70 degrees C), the solvothermal reaction of Zn(NO3)(2).6 H2O with rac-HPAPA in methanol does not lead to any change in the ligand and results in the formation of a chiral (P2(1)2(1)2(1)) coordination polymer [Zn(papa)(NO3)] (3). The same reaction of Cd(ClO4)(2).6 H2O with HPAPA also does not lead to any change in ligand and results in the formation of noncentric (Cc) coordination polymer [Cd(papa)(Hpapa)]ClO4.H2O (4). The network topology of both 1 and 3 is 10,3a, while 2 has a diamondoid-like (KDP-like, KDP=potassium dideuterophosphate) network. Particularly interesting from a topological perspective is that 4 has an unprecedented three-dimensional network. Compounds 1, 2, 3, and 4 are all second harmonic generation (SHG) active with 1 exhibiting the strongest response, while only 4 also displays good ferroelectric properties.

Journal Article↗
PubMed2004

Successful treatment of oral verrucous hyperplasia with topical 5-aminolevulinic acid-mediated photodynamic therapy.

Previous studies have shown a selective accumulation of 5-aminolevulinic acid (ALA)-derived protoporphrin IX (PpIX) in oral premalignant and malignant tissues. This provides a biologic rationale for the clinical use of ALA-mediated PDT (ALA-PDT) for oral premalignant and malignant lesions. In this study, five patients with oral verrucous hyperplasia (OVH) were treated with a new protocol of ALA-PDT composed of multiple 3-min irradiations with a light emitting diode (LED) red light at 635+/-5 nm separated with several 3-min rests for a total of 1000 s (fluence rate, 100 mW/cm(2); light exposure dose, 100 J/cm(2)) after topical application of 20% ALA for 1.5 or 2 h. Topical ALA-PDT was repeated once a week until the complete regression of the lesion. Complete regression of all OVH lesions was observed after 1-3 treatments (average, 2 treatments) of topical ALA-PDT. At an average follow-up of 5.6 months (range, 3-11 months), all the five OVH patients were free of tumor recurrence. We conclude that topical ALA-PDT with fractionated irradiations by an LED red light at 635+/-5 nm is an effective and successful treatment modality for OVH.

Adult↗
PubMed2004

Expression of hepatocyte growth factor and c-met protein is significantly associated with the progression of oral squamous cell carcinoma in Taiwan.

BACKGROUND: Hepatocyte growth factor (HGF) is a pleotropic growth factor that regulates cell proliferation, migration, survival, tumor angiogenesis, and tumor cell invasion and metastasis. Its diverse biological effects are mediated through its interaction with its receptor, c-met protein. METHODS: In this study, we examined the expression of HGF and c-met protein in 93 specimens of oral squamous cell carcinoma (OSCC), 10 specimens of oral epithelial dysplasia (OED), 14 specimens of oral epithelial hyperkeratosis (OEH), and 16 specimens of normal oral mucosa (NOM) by immunohistochemistry. The HGF and c-met labeling indices (LIs) in OSCC, OED, OEH, and NOM groups were calculated and compared between groups. The correlation between the expression of HGF or c-met in OSCCs and clinicopathological parameters, or survival of OSCC patients was analyzed statistically to investigate the possible influence of HGF or c-met on the progression and prognosis of OSCCs in Taiwan. RESULTS: Positive HGF or c-met staining was mainly cytoplasmic. The mean HGF LI increased significantly from NOM (3.1 +/- 5.1%) through OEH (32.5 +/- 19.8%) and OED (52.0 +/- 19.3%) to OSCC (71.9 +/- 28.6%; P = 0.000). The mean c-met LI also increased significantly from NOM (25.8 +/- 30.8%) and OEH (34.4 +/- 19.3%) through OED (53.0 +/- 20.0%) to OSCC (73.0 +/- 29.4%; P = 0.000). Statistical analysis showed that the c-met LI in either the tumor center or invasion front was significantly associated with T status, N status, and clinical staging of OSCC. However, only the HGF LI in the tumor invasion front was significantly correlated with N status and clinical staging of OSCC. CONCLUSION: Our results suggest that the expression of HGF and c-met protein is an early event in oral carcinogenesis in Taiwan. The HGF LI in the tumor invasion front and the c-met LI in either the tumor center or invasion front can predict the progression of OSCCs in Taiwan.

Adult↗