Paired gap states in a semiconducting carbon nanotube: Deep and shallow levels

Several paired, localized gap states were observed in semiconducting single-wall carbon nanotubes using spatially resolved scanning tunneling spectroscopy. A pair of gap states is found far from the band edges, forming deep levels, while the other pair is located near the band edges, forming shallow levels. With the help of a first-principles study, the former is explained by a vacancy-adatom complex while the latter is explained by a pentagon-heptagon structure. Our experimental observation indicates that the presence of the gap states provides a means to perform local band-gap engineering as well as doping without impurity substitution.open433

Estimating the malaria transmission of Plasmodium vivax based on serodiagnosis

Background: Plasmodium vivax re-emerged in 1993 and has now become a major public health problem during the summer season in South Korea. The aim of this study was to interpret and understand the meaning of seroepidemiological studies for developing the best malaria control programme in South Korea. Methods: Blood samples were collected in Gimpo city, Paju city, Yeoncheon County, Cheorwon County and Goseong County of high risk area in South Korea. Microscopy was performed to identify patients infected with P. vivax. Antibody detection for P. vivax was performed using indirect fluorescent antibody test (IFAT). Results: A total of 1,574 blood samples was collected from participants in the study areas and evaluated against three parameters: IFAT positive rate, annual antibody positive index (AAPI), and annual parasite index (API). The IFAT positive rate was 7.24% (n = 114). Of the five study areas, Gimpo had the highest IFAT positive rate (13.68%) and AAPI (4.63). Yeongcheon had the highest API in 2005 (2.06) while Gimpo had the highest API in 2006 (5.00). No correlation was observed between any of the three parameters and study sites' distance from the demilitarized zone (DMZ). Conclusions: These results showed that P. vivax antibody levels could provide useful information about the prevalence of malaria in endemic areas. Furthermore, AAPI results for each year showed a closer relationship to API the following year than the API of the same year and thus could be helpful in predicting malaria transmission risks

Comparison of Rapid Diagnostic Tests for the Detection of Plasmodium vivax Malaria in South Korea

South Korea is one of many countries with endemic Plasmodium vivax malaria. Here we report the evaluation of four rapid diagnostic tests (RDTs) for diagnosis of this disease. A total of 253 subjects were enrolled in the study. The sensitivities, specificities and agreement frequencies were estimated by comparing the four RDTs against the standard of nested-PCR and microscopic examination. The CareStartTM and SD Bioline had higher test sensitivities (99.4 and 98.8%, respectively) compared with the NanoSign and Asan Easy tests (93.0 and 94.7%, respectively). The CareStartTM and SD Bioline tests could detect P. vivax in samples with parasite densities <150/μl, which was a slightly better performance than the other two RDTs. The quantitative accuracy of the four RDTs was also estimated by comparing results with P. vivax counts from blood samples. Lower test price would result in increased use of these RDTs in the field. The results of this study contribute valuable information that will aid in the selection of a diagnostic method for the detection of malaria

Comparison of the antibody responses to Plasmodium vivax and Plasmodium falciparum antigens in residents of Mandalay, Myanmar

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to investigate the profile of antibodies against several antigens of <it>Plasmodium vivax </it>and <it>Plasmodium falciparum </it>in Mandalay, Myanmar.</p> <p>Methods</p> <p>Malaria parasites were identified by microscopic examination. To test the antibodies against <it>P. vivax </it>and <it>P. falciparum </it>in sera, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood parasite antigens. An enzyme-linked immunosorbent assay (ELISA) was performed with circumsporozoite protein (CSP), Pvs25 and Pvs28 recombinant proteins of transmission-blocking vaccine candidates for <it>P. vivax</it>, and liver stage specific antigen-1 and -3 (PfLSA-1, PfLSA-3) for <it>P. falciparum</it>.</p> <p>Results</p> <p>Fourteen patients among 112 were found to be infected with <it>P. vivax </it>and 26 with <it>P. falciparum </it>by thick smear examination. Twenty-three patients were found to be infected with <it>P. vivax</it>, 19 with <it>P. falciparum </it>and five with both by thin smear examination. Blood samples were divided into two groups: Group I consisted of patients who were positive for infection by microscopic examination, and Group II consisted of those who showed symptoms, but were negative in microscopic examination. In <it>P. falciparum</it>, IgG against the blood stage antigen in Group I (80.8%) was higher than in Group II (70.0%). In <it>P. vivax</it>, IgG against the blood stage antigen in Group I (53.8%) was higher than in Group II (41.7%). However, the positivity rate of the PvCSP VK210 subtype in Group II (40.0%) was higher than in Group I (23.1%). Similarly for the PvCSP VK247 subtype, Group II (21.7%) was higher than that for Group I (9.6%). A similar pattern was observed in the ELISA using Pvs25 and Pvs28: positive rates of Group II were higher than those for Group I. However, those differences were not shown significant in statistics.</p> <p>Conclusions</p> <p>The positive rates for blood stage antigens of <it>P. falciparum </it>were higher in Group I than in Group II, but the positive rates for antigens of other stages (PfLSA-1 and -3) showed opposite results. Similar to <it>P. falciparum</it>, the positive rate of pre-blood stage (CSP VK210 and 247 subtype) and post-blood stage (Pvs25 and 28) antigens of <it>P. vivax </it>were higher in Group II than in Group I. Therefore, sero-diagnosis is not helpful to discriminate between malaria patients and symptomatic individuals during the epidemic season in Myanmar.</p

Estimating the malaria transmission of Plasmodium vivax based on serodiagnosis

Abstract Background: Plasmodium vivax re-emerged in 1993 and has now become a major public health problem during the summer season in South Korea. The aim of this study was to interpret and understand the meaning of seroepidemiological studies for developing the best malaria control programme in South Korea. Methods: Blood samples were collected in Gimpo city, Paju city, Yeoncheon County, Cheorwon County and Goseong County of high risk area in South Korea. Microscopy was performed to identify patients infected with P. vivax. Antibody detection for P. vivax was performed using indirect fluorescent antibody test (IFAT). Results: A total of 1,574 blood samples was collected from participants in the study areas and evaluated against three parameters: IFAT positive rate, annual antibody positive index (AAPI), and annual parasite index (API). The IFAT positive rate was 7.24% (n = 114). Of the five study areas, Gimpo had the highest IFAT positive rate (13.68%) and AAPI (4.63). Yeongcheon had the highest API in 2005 (2.06) while Gimpo had the highest API in 2006 (5.00). No correlation was observed between any of the three parameters and study sites&apos; distance from the demilitarized zone (DMZ). Conclusions: These results showed that P. vivax antibody levels could provide useful information about the prevalence of malaria in endemic areas. Furthermore, AAPI results for each year showed a closer relationship to API the following year than the API of the same year and thus could be helpful in predicting malaria transmission risks

Open Access

The development of loop-mediated isothermal amplification targeting alpha-tubulin DNA for the rapid detection of Plasmodium viva

Molecular Cloning of Plasmodium vivax Calcium-Dependent Protein Kinase 4

A family of calcium-dependent protein kinases (CDPKs) is a unique enzyme which plays crucial roles in intracellular calcium signaling in plants, algae, and protozoa. CDPKs of malaria parasites are known to be key regulators for stage-specific cellular responses to calcium, a widespread secondary messenger that controls the progression of the parasite. In our study, we identified a gene encoding Plasmodium vivax CDPK4 (PvCDPK4) and characterized its molecular property and cellular localization. PvCDPK4 was a typical CDPK which had well-conserved N-terminal kinase domain and C-terminal calmodulin-like structure with 4 EF hand motifs for calcium-binding. The recombinant protein of EF hand domain of PvCDPK4 was expressed in E. coli and a 34 kDa product was obtained. Immunofluorescence assay by confocal laser microscopy revealed that the protein was expressed at the mature schizont of P. vivax. The expression of PvCDPK4-EF in schizont suggests that it may participate in the proliferation or egress process in the life cycle of this parasite

Prevalence of Clonorchis sinensis Metacercariae in Freshwater Fish from Three Latitudinal Regions of the Korean Peninsula

A large-scale survey was conducted to investigate the infection status of fresh water fishes with Clonorchis sinensis metacercariae (CsMc) in 3 wide regions, which were tentatively divided by latitudinal levels of the Korean peninsula. A total of 4,071 freshwater fishes were collected from 3 regions, i.e., northern (Gangwon-do: 1,543 fish), middle (Chungcheongbuk-do and Gyeongsangbuk-do: 1,167 fish), and southern areas (Jeollanam-do, Ulsan-si, and Gyeongsangnam-do: 1,361 fish). Each fish was examined by the artificial digestion method from 2003 to 2010. In northern areas, only 11 (0.7%) fish of 2 species, Pungtungia herzi and Squalidus japonicus coreanus from Hantan-gang, Cheolwon-gun, Gangwon-do were infected with av. 2.6 CsMc. In middle areas, 149 (12.8%) fish were infected with av. 164 CsMc. In southern areas, 538 (39.5%) fish were infected with av. 159 CsMc. In the analysis of endemicity in 3 regions with an index fish, P. herzi, 9 (6.2%) of 146 P. herzi from northern areas were infected with av. 2.8 CsMc. In middle areas, 34 (31.8%) of 107 P. herzi were infected with av. 215 CsMc, and in southern areas, 158 (92.9%) of 170 P. herzi were infected with av. 409 CsMc. From these results, it has been confirmed that the infection status of fish with CsMc is obviously different among the 3 latitudinal regions of the Korean peninsula with higher prevalence and burden in southern regions