Higher Peak Area Research Articles

Large-scale isotype-specific quantification of Serum amyloid A 1/2 by multiple reaction monitoring in crude sera

Quantification is an essential step in biomarker development. Multiple reaction monitoring (MRM) is a new modified mass spectrometry-based quantification technology that does not require antibody development. Serum amyloid A (SAA) is a positive acute-phase protein identified as a lung cancer biomarker in our previous study. Acute SAA exists in two isoforms with highly similar (92%) amino acid sequences. Until now, studies of SAA have been unable to distinguish between SAA1 and SAA2. To overcome the unavailability of a SAA2-specific antibody, we developed MRM methodology for the verification of SAA1 and SAA2 in clinical crude serum samples from 99 healthy controls and 100 lung adenocarcinoma patients. Differential measurement of SAA1 and SAA2 was made possible for the first time with the developed isotype-specific MRM method. Most healthy control samples had small or no MS/MS peaks of the targeted peptides otherwise, higher peak areas with 10- to 34-fold increase over controls were detected in lung cancer samples. In addition, our SAA1 MRM data demonstrated good agreement with the SAA1 enzyme-linked immunosorbent assay (ELISA) data. Finally, successful quantification of SAA2 in crude serum by MRM, for the first time, shows that SAA2 can be a good biomarker for the detection of lung cancers.

Effect of functionalized multi-walled carbon nanotubes on L02 cells

To investigate the cytotoxic effect of multi-walled carbon nanotubes (MWCNTs) on human liver L02 cells and its relevant mechanism. MWCNTs, carboxyl modification MWCNTs (MWCNTs-COOH), and hydroxyl modification MWCNTs (MWCNTs-OH) were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The carbon nanotubes at concentrations of 12.5, 25, 50, 100, and 200 μg/ml were incubated with human liver L02 cells for 24, 48 and 72 hours, respectively. The cell viability was evaluated by water soluble tetrazolium salts assay and the intercellular reactive oxygen species induced by the carbon nanotubes were detected by 2', 7'-dichlorodihydrofluorescein diacetate method. Transmission electron microscope showed that the average outside diameters (10 to 20 nm) and the average length (10 to 30 μm) of the three MWCNTs were similar. Scanning electron microscope indicated that the three MWCNTs had a similar surface topography. X-ray photoelectron spectroscopy demonstrated that the MWCNTs-COOH and MWCNTs-OH had relatively high peak areas at 289 and 286ev, respectively,indicating that they have been modified by carboxyl and hydroxyl groups,respectively. Water soluble tetrazolium salts assay showed that the MWCNTs-COOH was less cytotoxic when compared to MWCNTs which demonstrated to be slightly more cytotoxic than MWCNTs-OH. The capability to induce increase in intracellular reactive oxygen species was in the following order: MWCNTs > MWCNTs-COOH > MWCNTs-OH. Modification of MWCNTs with carboxyl group and hydroxyl group improves the biocompatibility of MWCNTs to some extents. MWCNTs-COOH has better compatibility than MWCNTs at the low concentration,and MWCNTs-OH showed better compatibility than MWCNTs after 48 hours. Different mechanisms may be involved in the interaction between cells and the MWCNTs with different chemical surfaces.

Simultaneous optimization by neuro-genetic approach for analysis of plant materials by laser induced breakdown spectroscopy

A simultaneous optimization strategy based on a neuro-genetic approach is proposed for selection of laser induced breakdown spectroscopy operational conditions for the simultaneous determination of macro-nutrients (Ca, Mg and P), micro-nutrients (B, Cu, Fe, Mn and Zn), Al and Si in plant samples. A laser induced breakdown spectroscopy system equipped with a 10 Hz Q-switched Nd:YAG laser (12 ns, 532 nm, 140 mJ) and an Echelle spectrometer with intensified coupled-charge device was used. Integration time gate, delay time, amplification gain and number of pulses were optimized. Pellets of spinach leaves (NIST 1570a) were employed as laboratory samples. In order to find a model that could correlate laser induced breakdown spectroscopy operational conditions with compromised high peak areas of all elements simultaneously, a Bayesian Regularized Artificial Neural Network approach was employed. Subsequently, a genetic algorithm was applied to find optimal conditions for the neural network model, in an approach called neuro-genetic. A single laser induced breakdown spectroscopy working condition that maximizes peak areas of all elements simultaneously, was obtained with the following optimized parameters: 9.0 µs integration time gate, 1.1 µs delay time, 225 (a.u.) amplification gain and 30 accumulated laser pulses. The proposed approach is a useful and a suitable tool for the optimization process of such a complex analytical problem.

제주 자생식물 고압용매 추출물의 통합적 항산화 능력

제주 자생식물 20종을 대상으로 고압용매 추출(추출용매 100% methanol, 추출 온도 40℃, 추출 압력 13.6 ㎫, 추출시간 10분)하여 총페놀 함량과 통합적 항산화 능력을 측정하고 폴리페놀 성분을 동정하였다. 추출수율은 붉나무, 말오줌 때, 사방오리나무, 사람주나무, 팥배나무가 각각 21.8, 21.5, 21.1, 20.7, 20.1%로 가장 높았다. 총페놀 함량은 아그배가 68.3 ㎎ GAE/g로 가장 높았고, 다음으로 사람주나무, 석위, 말오줌때가 각각 57.6, 56.6, 55.1 ㎎ GAE/g을 나타내었다. 수용성 항산화 능력은 이질풀, 사람주나무, 산딸나무, 붉나무가 각각 598, 394, 293, 270 μ㏖ ascorbic acid equivalent/g로 높았고, 지용성 항산화 능력은 백량금, 새우나무, 이질풀, 붉가시나무가 611, 314, 296, 242 μmol trolox equivalent/g로 높았다. GC/MS에 의한 폴리페놀성분을 동정한 결과 15개의 주요 피크를 얻었으며, 그 중 2종의 폴리페놀류(gallic acid(체류시간 19.7분)와 quercetin(체류시간 33.5 분)), ascorbic acid(체류시간 35.3분) 그리고 다수의 지방산류(체류시간 18.6, 21.0, 21.8, 21.9, 23.6분)를 확인할 수 있었는데, 이 중 gallic acid는 다른 성분보다 peak area가 높은 것으로 나타나 사람주나무의 가장 중요한 폴리페놀 성분으로 추정되었다.

RADIATION CROSSLINKING OF BIODEGRADABLE POLY(BUTYLENE SUCCINATE) AT HIGH TEMPERATURE

Poly(butylene succinate), (PBS) with different molecular weight was γ-irradiated at different temperatures and various doses. PBS with high molecular weight and smaller peak area of crystal melting gave the highest gel content at the same temperatures and dose. A two-step irradiation (irradiation in molten state after irradiation at room temperature) gave the highest gel content in different conditions. This is due to the formation of network structure by pre-irradiation at room temperature that leads to less degradation. PBS prepared by two step irradiation was effective for improvement of heat stability because of high gel content formation. Unirradiated PBS sheets broke immediately at 110°, while the irradiated sample (gel fraction, 50%) by a two step-method, did not break even up to 200 minutes at 130°C. The PBS sheets are biodegradable even after crosslinking.

Non-linearity of the high temperature peak area ratio of 6LiF:Mg,Ti (TLD-600)

Thermoluminescent dosemeters of 6LiF:Mg,Ti (TLD-600) were exposed to high-energy heavy ion beams (He, C, Ne, and Ar) and 137Cs γ-rays and the glow curves were analyzed. The height of the main peak (peak 5) at about 200°C slightly increased for He from γ-rays and decreased for heavier ions with increasing Linear Energy Transfer (LET). Whereas the high temperature peak (peak 7) area around 260°C simply increased. Non-linearity was seen between the LET and the high temperature peak (peak 7) area ratio (HTR) which was calculated as the TL integrated over 225–275°C from the peak 5 normalized glow curve. Based on these results, average LET and quality factor were estimated for an assumed LET spectra of space radiation by using the HTR method. Considerable differences were found between these estimations and true values.

Fluctuation of the South Pacific Albacore Stocks (Thynnus alalunga) Relative to the Sea Surface Temperature

This paper presents a paleomagnetic intensity record for late Quaternarytime in Taiwan.Samples came from the lower part of an 86-metersedimentary piston core drilled in the Wukou area of the Taipei Basin.Theage interval of the studied portion,as determined by C-14 dating(Liu et al.,1994),was proposed to be between 9,000 yr.B.P. and 21,000 yr.B.P.Naturalremanent magnetization(NRM),anhysteresis remanent magnetization(ARM)and low field magnetic susceptibility(x)of the samples were analyzed.Results show that the stratigraphical variation patterns of NRM/x andARM/x,after 20 mT alternating field demagnetization treatments on bothNRM and ARM of samples,are very similar.This implies that the acquisitionof NRM and ARM are under the same magnetic mineralogical conditions.Thus,the ratio of the NRM to ARM at this demagnetization stagecould represent the paleointensity secular variation of geomagnetic field inthe area studied.Four major high peak areas were found in the NRM/ARM record(after20 mT demagnetization).These were at about 60m,70m,80m and 90m in depth.Three of them could be correlated to another intensity recordanalyzed from a lacustrine sediment core drilled in the Taihu area of China(Wang et al.,1997).Comparing these two records,and the C-14 dated agesof the two cores,the correspondent ages of the four intensity high peakswere proposed to be about 10,000,13,500,17,500 and 21,000 years beforepresent,respectively.In addition,the age assigned to the peak at about 60m in depth is also supported by the volcanic records in Japan(Tanaka,1990).Thus,the record of this study presents a regional secular variationpattern of paleo-intensity of the earth's magnetic field during the last 9,000to 21,000 years in East Asia.

Improved quantitative electron probe X‐ray microanalysis of biological cryosections using an EDS germanium detector and a super‐atmosphere thin window (SuperATW)

A new Link energy-dispersive GEM detector with SuperATW window was tested for quantitative electron probe microanalysis of low calcium and sodium concentrations ([Ca], [Na]) in intracellular compartments of cardiac myocytes. We compare Ca profiles with high count statistics and similar peak area collected under the same conditions with either a Be-windowed Si and a Ge SuperATW detector. The height of the Ca peak was increased by 7%, the full width at half-maximum height was reduced by 9% with the Ge detector. The counts statistics of the Ca K alpha peak improved by 9% and the partial overlap with the K K beta peak was better deconvoluted. We calculate [Ca] and errors of the single measurement in mitochondria of guinea-pig cardiac myocytes from spectra acquired with a Si or Ge detector. For identical analysis conditions, the [Ca] were identical; however, with the Ge SuperATW detector, the calculated error of the single measurement was only 1/2.7 of that calculated from measurements with the Si detector. We compare the peak area of identical [Na] in spectra collected with the Be-windowed Si detector and Ge SuperATW detector. The peak area was significantly higher with the SuperATW Ge than with the Si detector and Be window, whereas the continuum in the range 4-10 keV was comparable, demonstrating the improved sensitivity for low atomic elements such as Na of the Ge SuperATW detector. [Na] and errors of the single measurement in mitochondria of quiescent guinea-pig cardiac myocytes were calculated from spectra acquired with the Si or the Ge detector. The use of the Ge SuperATW detector improved the detectability limit for sodium by more than 80% and reduced the error of the single measurement by a factor of 7-8.

Analysis of transfer RNA during the early embryogenesis of the freshwater teleost, Heteropneustes fossilis.

Total RNA as well as transfer RNA were quantified from mature ova apart from four different embryonic stages namely mid-cleavage, early gastrula, mid-gastrula and organogenesis of the freshwater teleost Heteropneustes fossilis. Total RNA as well as transfer RNA quantity follow a similar variation pattern, being maximum during mid-gastrulation. When analysed by total amino acid acceptance capacity, transfer RNA shows its maximum activity during mid-gastrulation. This coincides with the higher ratio of tRNA to total RNA at this stage. The relative aminoacylation capacity for Ser, Gly, Asn and Thr are found to be higher (9-34%) compared to that for other amino acids. Total tRNA, resolved into three peaks upon HPLC fractionation, shows a high cumulative peak area during mid-gastrulation and organogenesis. These results indicate a switch over of maternal to embryonic translation machinery during gastrulation.

Determination of Bioactive and Pharmaceutical Components of Croton bonplandianus by GC-MS Analysis

The present study sought to analyze the chloroformic extract of aerial parts of the Indian medicinal plant Croton bonplandianus by GC-MS analysis and to explore the presence of major phytoconstituents. Gas chromato-graphy–mass spectrometric (GC–MS) analysis was carried out on the chloroformic extract of aerial parts of Croton bonplandianus for identification of phytocomponents in the plant while the mass spectra of the components found in the extract was matched with the National Institute of Standards and Technology (NIST) library. There are 59 bioactive components were identified from chloroformic extract of Croton bonplandianus. Hence, it is of interest to investigate the presence of phytoconstituents from the chloroformic extract of Croton bonplandianus by using GC-MS method. The highest peak area (%) of 21.710 was obtained by Phenol,2-methyl1-5-(1,2,2-trimethyl cyclo pentyl)-(s) (Retention time 28.236) and the lowest peak area (%) of 0.76 was obtained by Bicyclo [7,2,0] undecane,10,10-dimethyl1-2,6-bis (methylene)-[1S-1R*,9S*)] (Retention time 29.396). Results confirmed the presence of therapeutically potent compounds in the plant extract. This study is helpful to predict the formula and structure of biomolecules which can be used as drugs and further investigation may lead to the development of drug formulation.