Nanophase Catalyst Layer for Direct Methanol Fuel Cells

Chang Hyuk,Kim Jirae The Korean Electrochemical Society 2001 한국전기화학회지 Vol.4 No.4

마그네트론 스퍼터링 방법에 의하여 Nanophase 촉매층을 형성하여 Direct Methanol Fuel Cell(DMFC)에 적용하였다. 일반적인 박막 증착 방법보다 높은 압력 (Ar/He혼합기체)에서 금속 Target과 탄소 Target을 동시에 스퍼터링하여 내피온막 위에 직접 코팅함으로써 기공성 있는 PtRu혹은 Pt및 탄소입자를 포함한 새로운 구조의 촉매층을 형성하였다. 본 방법에 의하여 $1.5mg/cm^2$의 PtRu(Anode) 및 $1mg/cm^2$ Pt(Cathode) 로딩으로 2M Methanol, 1 Bar공기, $80^{\circ}C$조건에서 $45mW/cm^2$의 출력을 얻을 수 있었으며, 이는 기존의 상용방법에 의하여 제조된 전극보다 같은 조건에서 $30\%$의 성능향상을 제시한 것이다. 이는 Nanophase촉매층 구조로 인하여 초미세 분말을 적용하였고, 많은 량의 원자들이 입계에 배열하게 됨으로써 촉매반응을 원활하게 하고,연료의 공급을 효율적으로 해준 것에 기안한 것으로 판단된다. 그러므로, 본 연구의 결과를 응용할 경우 DMFC를 휴대용 전자기기에 적용함에 있어서 성능향상 및 가격경쟁력 확보에 도움을 줄 것으로 기대된다. Nanophase catalyst layer for direct methanol fuel cell has been fabricated by magnetron sputtering method. Catalyst metal targets and carbon were sputtered simultaneously on the Nafion membrane surface at abnormally higher gas (Ar/He mixture) pressure than that of normal thin film processing. They could be coated as a novel structure of catalyst layer containing porous PtRu or Pt and carbon particles both in nanometer range. Membrane electrode assembly made with this layer led to a reduction of the catalyst loading. At the catalyst loading of 1.5mg $PtRu/cm^2$ for anode and 1mg $Pt/cm^2$ for cathode, it could provide $45 mW/cm^2$ in the operation at 2 M methanol, 1 Bar Air at 80"C. It is more than $30\%$ increase of the power density performance at the same level of catalyst loading by conventional method. This was realized due to the ultra fine particle sizes and a large fraction of the atoms lie on the grain boundaries of nanophase catalyst layer and they played an important role of fast catalyst reaction kinetics and more efficient fuel path. Commercialization of direct methanol fuel cell for portable electronic devices is anticipated by the further development of such design.

THE OPTIMIZATION METHOD OF GASKETS FOR HT-PEM FUEL CELLS

Jeongsik Ko,Tae-won Song,Jirae Kim 한국신재생에너지학회 2012 AFORE Vol.2012 No.-

Inheritance of qualitative traits and heterosis in bambara groundnut (Vigna subterranea (L.) Verdc.)

Jira Suwanprasert,Peerasak Srinives,Theerayut Toojinda,Sontichai Chanprame 한국유전학회 2007 Genes & Genomics Vol.29 No.3

Genetic inheritance studies and varietal improvement programs in bambara groundnut have not been initiated in the past due to failure in hybridization. We successfully produced 23 F1 seeds from four crosses among the morphologically distinct lines, "TVsu 11," "TVsu 870," "TVsu 1061," and a Thai local variety "Thung Yang Daeng." The phenotypes of the F1 showed that the reddish-purple pod and red seed coat were dominant over the white pod and cream seed coat. The F2 from the cross between a reddish-purple pod line and a white pod line, and between a red seed coat line with a cream seed coat line segregated in a 3:1 ratio. This simple Mendelian inheritance was confirmed by the segregation ratio in the F3 generation. In terms of petiole color, reddish-purple was dominant over green. However, the segregation in the F2 generation revealed that this trait was controlled by more than one gene locus. For leaflet shape, incomplete dominance was found in the F2 population of the cross between "Thung Yang Daeng," with a long narrow leaflet, and "TVsu 870," with a lanceolate leaflet, giving a 1:2:1 segregation ratio among long narrow:moderately long:lanceolate leaflets. Significant hybrid vigor of the F1, as determined from heterosis and heterobeltiosis, was found in petiole length, fresh pericarp thickness, and seed size.

Polymorphisms in TP53 (rs1042522), p16 (rs11515 and rs3088440) and NQO1 (rs1800566) Genes in Thai Cervical Cancer Patients with HPV 16 Infection

Chansaenroj, Jira,Theamboonlers, Apiradee,Junyangdikul, Pairoj,Swangvaree, Sukumarn,Karalak, Anant,Chinchai, Teeraporn,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

The risk of cervical cancer development in women infected with HPV varies in relation to the individual host's genetic makeup. Many studies on polymorphisms as genetic factors have been aimed at analyzing associations with cervical cancer. In this study, single nucleotide polymorphisms (SNPs) in 3 genes were investigated in relation to cervical cancer progression in HPV16 infected women with lesions. Two thousand cervical specimens were typed by PCR sequencing methods for TP53 (rs1042522), p16 (rs11515 and rs3088440) and NQO1 (rs1800566). Ninety two HPV16 positive cases and thirty two normal cases were randomly selected. Analysis of TP53 (rs1042522) showed a significantly higher frequency in cancer samples (OR=1.22, 95%CI=1.004-1.481, p-value=0.016) while differences in frequency were not significant within each group (p-value=0.070). The genotype distributions of p16 (rs11515 and rs3088440) and NQO1 (rs1800566) did not show any significantly higher frequency in cancer samples (p-value=0.106, 0.675 and 0.132, respectively) or within each group (p-value=0.347, 0.939 and 0.111, respectively). The results indicated that the polymorphism in TP53 (rs1042522) might be associated with risk of cervical cancer development in HPV16 infected women. Further studies of possible mechanisms of influence on cervical cancer development would be useful to manage HPV infected patients.

Whole Genome Analysis of Human Papillomavirus Type 16 Multiple Infection in Cervical Cancer Patients

Chansaenroj, Jira,Theamboonlers, Apiradee,Junyangdikul, Pairoj,Swangvaree, Sukumarn,Karalak, Anant,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

The characterization of the whole genome of human papillomavirus type 16 (HPV16) from cervical cancer specimens with multiple infections in comparison with single infection samples as the oncogenic potential of the virus may differ. Cervical carcinoma specimens positive for HPV16 by PCR and INNO-LiPA were randomly selected for whole genome characterization. Two HPV16 single infection and six HPV16 multiple infection specimens were subjected to whole genome analysis by using conserved primers and subsequent sequencing. All HPV16 whole genomes from single infection samples clustered in the European (E) lineage while all multiple infection specimens belonged to the non-European lineage. The variations in nucleotide sequences in E6, E7, E2, L1 and Long control region (LCR) were evaluated. In the E6 region, amino acid changes at L83V were related to increased cancer progression. An amino acid variation N29S within the E7 oncoprotein significantly associated with severity of lesion was also discovered. In all three domains of the E2 gene non synonymous mutations were found. The L1 region showed various mutations which may be related to conformation changes of viral epitopes. Some transcription factor binding sites in the LCR region correlated to virulence were shown on GRE/1, TEF-1, YY14 and Oct-1. HPV16 European variant prone to single infection may harbor a major variation at L83V which significantly increases the risk for developing cervical carcinoma. HPV16 non-European variants prone to multiple infections may require many polymorphisms to enhance the risk of cervical cancer development.

High-risk Human Papillomavirus Genotype Detection by Electrochemical DNA Chip Method

Chansaenroj, Jira,Theamboonlers, Apiradee,Chinchai, Teeraporn,Junyangdikul, Pairoj,Swangvaree, Sukumarn,Karalak, Anant,Takahashi, Masayoshi,Nikaido, Masaru,Gemma, Nobuhiro,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

High-risk human papillomavirus (HPV) genotypes are the major cause of cervical cancer. Hence, HPV genotype detection is a helpful preventive measure to combat cervical cancer. Recently, several HPV detection methods have been developed, each with different sensitivities and specificities. The objective of this study was to compare HPV high risk genotype detection by an electrochemical DNA chip system, a line probe assay (INNO-LiPA) and sequencing of the L1, E1 regions. A total of 361 cervical smears with different cytological findings were subjected to polymerase chain reaction-sequencing and electrochemical DNA chip assessment. Multiple infections were found in 21.9% (79/361) of the specimens, most prevalently in 20-29-year olds while the highest prevalence of HPV infection was found in the 30-39-year age group. The most prevalent genotype was HPV 16 at 28.2% (138/489) followed by HPV 52 at 9.6% (47/489), with the other types occurring at less than 9.0%. The electrochemical DNA chip results were compared with INNO-LiPA and sequencing (E1 and L1 regions) based on random selection of 273 specimens. The results obtained by the three methods were in agreement except for three cases. Direct sequencing detected only one predominant genotype including low risk HPV genotypes. INNO-LiPA identified multiple infections with various specific genotypes including some unclassified-risk genotypes. The electrochemical DNA chip was highly accurate, suitable for detection of single and multiple infections, allowed rapid detection, was less time-consuming and was easier to perform when compared with the other methods. It is concluded that for clinical and epidemiological studies, all genotyping methods are perfectly suitable and provide comparable results.

Whole Genome Analysis of Human Papillomavirus Genotype 11 from Cervix, Larynx and Lung

Chansaenroj, Jira,Theamboonlers, Apiradee,Junyangdikul, Pairoj,Supiyaphan, Pakpoom,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

The prevalence of human papillomavirus genotypes differs in various target organs. HPV16 is the most prevalent genotype in the cervix while genotypes 6 and 11 are highly prevalent in skin and aero-digestive tract infections. In this study HPV11 positive specimens were selected from cervix, larynx and lung biopsy tissue to analyze the whole genome by PCR and direct sequencing. Five HPV11 whole genomes were characterized, consisting of two cervical specimens, two laryngeal specimens and one lung specimen. The results showed high homology of HPV11 in these organs. Phylogenetic analysis showed that all HPV11 derived from various organs belonged to the same lineage. Molecular characterization and functional studies can further our understanding of virulence, expression or transmission. Additional studies on functional protein expression at different organ sites will also contribute to our knowledge of HPV infection in various organs.

Comparison of Four Human Papillomavirus Genotyping Methods: Next-generation Sequencing, INNO-LiPA, Electrochemical DNA Chip, and Nested-PCR

Pornjarim Nilyanimit,Jira Chansaenroj,Witthaya Poomipak,Kesmanee Praianantathavorn,Sunchai Payungporn,Yong Poovorawan 대한진단검사의학회 2018 Annals of Laboratory Medicine Vol.38 No.2

Background: Human papillomavirus (HPV) infection causes cervical cancer, thus necessitating early detection by screening. Rapid and accurate HPV genotyping is crucial both for the assessment of patients with HPV infection and for surveillance studies. Methods: Fifty-eight cervicovaginal samples were tested for HPV genotypes using four methods in parallel: nested-PCR followed by conventional sequencing, INNO-LiPA, electrochemical DNA chip, and next-generation sequencing (NGS).

Clinical Prediction Based on HPV DNA Testing by Hybrid Capture 2 (HC2) in Combination with Liquid-based Cytology (LBC)

Junyangdikul, Pairoj,Tanchotsrinon, Watcharaporn,Chansaenroj, Jira,Nilyaimit, Pornjarim,Lursinsap, Chidchanok,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Primary screening by HPV DNA testing is an effective method for reducing cervical cancer and has proven more sensitive than cytology. To advance this approach, many molecular methods have been developed. Hybrid capture 2 provides semi-quantitative results in ratios of relative light units and positive cutoff values (RLU/PC). Twenty-five thousand and five patients were included in this study to analyze the correlation between the ratio of RLU/PC and stage of cervical dysplasia. The results show that the RLU/PC ratios ranged from 0-3500 while almost normal cases, ASC-US and ASC-H, had values below 200. Of those samples negative for cytology markers, 94.6% were normal and their RLU/PC ratios were less than 4. With an RLU/PC ratio greater than 4 and less than or equal to 300, the percentages in all age groups were normal 53.6%, LSIL 20.2%, ASC-US 17.2%, HSIL 6.13%, ASC-H 2.72%, and AGC 0.11%, respectively. In contrast, 64.0% of samples with a RLU/PC ratio greater than 300 and less than or equal to 3500 were LSIL. These results should contribute to cost effective cervical cancer management strategies. Further studies of associations with particular HPV genotypes would be useful to predict the risk of progression to cancer.

Lack of Associations between TNF-α Polymorphisms and Cervical Cancer in Thai women

Chinchai, Teeraporn,Homchan, Krittaphak,Sopipong, Watanyoo,Chansaenroj, Jira,Swangvaree, Sukumarn,Junyangdikul, Pairoj,Vongpunsawad, Sompong,Poovorawan, Yong Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.3

The risk of developing cervical cancer in women infected with human papillomavirus (HPV) may be influenced by an individual's genetic susceptibility. Published data linking single nucleotide polymorphisms (SNPs) in the tumor necrosis factor-alpha (TNF-${\alpha}$) promoter region at positions -308G>A (rs1800629) and -238G>A (rs361525) to cervical cancer risk have been inconclusive. In this study, we examined 251 cervical specimens and classified them into two groups according to their cytological findings: 121 cancer cases and 130 controls (low-grade squamous intraepithelial lesion and normal cytology). All specimens were typed by PCR and sequencing for TNF-${\alpha}$ promoter -308G>A (rs1800629) and -238G>A (rs361525). The genotype distribution of SNPs in either rs1800629 or rs361525 did not significantly demonstrate higher frequency in the cancer group (p=0.621 and p=0.68, respectively). Based on these results, neither the TNF-${\alpha}$ promoter -308G>A (rs1800629) nor the -238G>A (rs361525) polymorphism presents a major risk factor for cervical cancer among Thai women. Larger studies are necessary to elucidate possible genetic mechanisms influencing cervical cancer development.