• Bulletin of the Korean Chemical Society
• /
• 제31권1호
• /
• pp.116-119
• /
• 2010

Adsorption structures of the self-assembled thin films of $\alpha$-cyano-4-hydroxycinnamic acid (CHCA) anchoring on $TiO_2$ surfaces have been studied by using temperature-dependent diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. From the presence of the strong $\nu(COO^-)$ band at ~1390 $cm^{-1}$ along with the disappearance of the OH bands in the carboxylic acid group in the DRIFT spectra at room temperature, CHCA appeared to adsorb onto $TiO_2$ surfaces as a carboxylate form. The absence of the out-of-plane benzene ring modes of CHCA in the DRIFT spectra suggests a rather vertical orientation of CHCA on $TiO_2$. Above ~220$ ^{\circ}C$, CHCA seemed to start to thermally degrade on $TiO_2$ surfaces referring from the disappearance of most vibrational modes in the DRIFT spectra, whereas the $\nu$(C ≡ N) bands were found to remain relatively conspicuous as the temperature increased even up to ~460$^{\circ}C$.

• Mass Spectrometry Letters
• /
• 제5권2호
• /
• pp.49-51
• /
• 2014

The effectiveness of tertiary matrices composed of the combination of three common matrices (dihydrobenzoic acid (DHB), ${\alpha}$-cyano-4-hydroxycinnamic acid (CHCA), and sinapinic acid (SA)) was compared with that of single or binary matrices in the analysis of polyethylene glycol (PEG) polymers ranging from 1400 to 10000 Da using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A tertiary matrix of 2,5-DHB+CHCA+SA was the most effective in terms of S/N ratios. CHCA and CHCA+SA produced the highest S/N ratios among the single matrices and the binary matrices, respectively. The improvement observed when using a tertiary matrix in analyses of PEG polymers by MALDI-TOF MS is believed to be due to the uniform morphology of the MALDI sample spots and synergistic effects arising from the mixture of the three matrix materials.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권9호
• /
• pp.3697-3701
• /
• 2015

Background: Cholangiocarcinoma (CHCA) is serious public health problem in Thailand, especially in the northeastern and northern regions. CHCA is known as one of the most aggressive malignant tumors associated with local invasion and a high rate of metastasis. A crucial step in the invasion process is the proteolytic degradation of the extracellular matrix (ECM) and basal membranes, for which several studies have shown a critical role played by matrix metalloproteinase-11 (MMP-11). Objective: This study aim to detect MMP-11 expression in CHCA specimens and any correlation with survival time. Materials and Methods: A retrospective analysis was conducted of 30 patients with CHCA in Rajvithi hospital, who had undergone immunohistochemical staining of MMP-11. Relationships between clinicopathological data and MMP-11 expression in CHCA specimens were analyzed by the ${\chi}^2$ test or Fisher's exact test. The estimated survival and the survival differences were analyzed by the Kaplan-Meier method and the log-rank test, respectively. Results: MMP-11 expression was found in 15 specimens (50%). The overall mean survival time is 237.0 days (95% CI 135.4-338.5, SD 271.9). Specimens with a positive MMP-11 had an average survival time of 136.7 days (95%CI 50.3-223.1, SD 156.0). Survival differences was signficant for the positive and negative MMP-11(p=0.022), but not well differentiated tumor and moderate to poor differentiated tumor (p=0.755), CA19-9 level of >1,000 and <1,000 (p=0.488), and between advanced and non-advanced staging (p=0.388). Conclusions: The positive MMP-11 expression indicates poor prognosis in CHCA specimens.

• Bulletin of the Korean Chemical Society
• /
• 제34권6호
• /
• pp.1708-1714
• /
• 2013

Polyhexamethylene guanidine (PHMG) polymers used as an active ingredient in an antibacterial humidifier disinfectant were reported to cause harm to the human health when inhaled, although physical contact with this material was known to present low toxicity to humans. It is therefore necessary to develop an optimal analysis method which enables detection and analysis of PHMG polymers. MALDI-TOF investigations of PHMG are performed with a variety of matrices, and it is found that CHCA and 2,5-DHB are excellent matrices which well reflects the polymer population even at high mass. For the provided PHMG sample, the number-average ($M_n$) and weight-average ($M_w$) molecular masses were determined to be 744.8 and 810.7, respectively, when the CHCA was used as a matrix. The rank of the matrices in terms of averaged molecular weight was CHCA ~2,5-DHB > 5-NSA > DHAP, THAP > ATT > IAA ~ super-DHB ~ HABA. In addition, PSD of the PHMG oligomer ions exhibited a few unique fragmenation characteristics. The formation of a- and c-type fragments was the major fragmentation pathway, and the 25-Da loss peaks generally accompanied a- and c-type fragments.

• Mass Spectrometry Letters
• /
• 제11권4호
• /
• pp.77-81
• /
• 2020

Characterization of the various chemical aspects of composite polymers is important for quality control of manufactured polymers. In this study, we compared three suitable matrices (α cyano-4-hydroxycinnamic acid [CHCA], 2,5 dihydroxy benzoic acid [2,5-DHB], and dithranol), to characterize various synthetic polymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Although the spectra obtained with the CHCA and 2,5-DHB matrices were generally good, in certain samples ghost peaks disappeared only when dithranol was used as the matrix. Furthermore, we examined the use of sodium trifluoroacetate (NaTFA) as an additive to reduce interference by metals and copolymers in the spectra. In conclusion, appropriate selection of a matrix, according to the characteristics of the polymer, and the use of additives to improve sensitivity are important considerations for polymer analysis and development.

• Parasites, Hosts and Diseases
• /
• 제32권1호
• /
• pp.13-18
• /
• 1994

간흡충은 담관내에 기생하면서 만성적 감염의 결과 최종적으로 담관암을 유발시키는 것으로 알려져 왔다. 실험동물에서 간흡충의 감염만으로는 담관암이 발생하지 않으며, 어떠한 외적 혹은 내적 발암성의 물질들과 병합하여 담관암이 형성하는 것으로 보고된 바 있다 본 실험은 햄스터에서 간흡충의 감염과 dimethylnitrosamine(DMN)의 병합작용으로 담관암이 발생되었다는 모델을 이용하여 "발암기전의 2단계이론" 상에서 간흡충의 역할을 밝혀보고자 하였다. 총 90마리의 햄스터를 15 마리씩 6군으로 나누었다. $DMN{\;}{\rightarrow}{\;}CS$군의 햄스터에서는 먼저 15 ppm의 DMN을 4주 동안 음수 투여하고, 1주 후에 간흡충을 15마리씩 인공감염시켰다. 그리고 5주 후에 piaziquantel로 간흡충을 치료하였다 $CS{\;}{\rightarrow}{\;}DMN$군에서는 먼저 간홉충을 감염시키고 5주 후에 praziquantel로 치료하였으며 1주 후부터 DMN을 4주동안 투여하였다. DMN + CS군에서는 DMN과 간흠충을 동시에 투여하였으며 4주 후에는 DMN을 제거하였다. DMN군과 CS군은 각각 DMN과 간흡충만을 투여하였고 대조군은 아무것도 투여하지 않았다. 모든 실험동물은 13주 후에 부검하였으며 조직병리학적인 방법으로 간장을 검경하여 진단하였다. 실험결과 담관암은 $DMN{\;}{\rightarrow}{\;}CS$군에서 3마리, DMN + CS군에서 11마리가 발생하였으며 나머지 군들에서는 암이 발생하지 않았다. 본 실험으로 2단계 발암기 전상에서 간흡충은 담관암발생을 촉진하는 효과를 보였음을 알수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제33권9호
• /
• pp.2955-2960
• /
• 2012

Product ion yields in the in- and post-source decays of three peptide ions, $[Y_5X+H]^+$ (X = Y (tyrosine), K (lysine), and R (arginine)), generated by matrix-assisted laser desorption ionization (MALDI) were measured at six wavelengths, 307, 317, 327, 337, 347, and 357 nm, using ${\alpha}$-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) as the matrices. The temperatures of the early and late plumes generated by MALDI were estimated via kinetic analysis of the product ion yield data. For both matrices, the temperature drop (${\Delta}T$), i.e. the difference in the temperature between the early and late plumes, displayed negative correlation with the absorption coefficient. This was in agreement with the previous reasoning that deeper laser penetration and larger amount of material ablation arising from smaller absorption coefficient would result in larger extent of expansion cooling. The results support the postulation of the expansion cooling occurring in the plume presented previously.