59 research outputs found
Colony formation in two Microcystis morphotypes: Effects of temperature and nutrient availability
No full textThe ability of Microcystis to form large colonies is a key trait that contributes to competition ability over other phytoplankton and facilitates the formation of surface scums in many freshwater systems. The effect of temperature and nutrients on this trait, however, is far from clear and needs further investigation, especially under a warmer climate and nutrient overloading in aquatic systems globally. In this study, two colonial strains of Microcystis (M. wesenbergii and M. ichthyoblabe) originally isolated from Lake Taihu in China, were used to investigate cyanobacterial aggregation under a range of temperatures (15-30 °C), phosphorus availability (0.004-8 mg P L-1), and nitrogen availability (0.04-40 mg N L-1). The mechanism of colony formation in Microcystis was determined based on growth rates and extracellular polysaccharide (EPS) contents. The colony size of both strains increased significantly when the temperature rose from 15 to 25 °C. A further increase in temperature from 25 to 30 °C, however, reduced the colony size of M. ichthyoblabe significantly, and, in contrast, increased the colony size of M. wesenbergii. Higher phosphorus availability promoted the formation of larger colonies in both strains. In comparison, nitrogen had no significant effect on the colony size. Furthermore, although EPS was a significant contributor to the formation of large colonies in colonial Microcystis, growth rate was a dominant driving factor in this process. The findings of this study highlight that warmer temperatures and phosphorus enrichment might enhance surface Microcystis scums directly through increasing the colony size. This study also provides new insights into the mechanism of colony formation in Microcystis.Zhipeng Duan, Xiao Tan, Keshab Parajuli, Sanjina Upadhyay, Danfeng Zhang, Xiaoqian Shu, Qianqian Li
Developing conducting polymer nanocomposites with carbon nanomaterials for molecular detection and fuel cell applications
No full textConducting polymers are attractive for chemical sensors because their conductivity and electrochemical activity is extremely sensitive to molecular interactions. The inherent specificity of the conducting polymer based sensors stems from the fact that only certain chemicals can trigger a dramatic conductance change. It can be made more specific by further chemical functionalization of the polymer. The use of conducting polymers (CPs) as low-cost electrocatalysts was also investigated in the early history of conducting polymer research and applications. However, their low environmental stability, low conductivity, and electrochemical activity limit their practical industrial applications. Inspired by the remarkable electronic and superior mechanical properties of carbon nanomaterials, especially carbon nanotubes (CNTs) and the relatively new material graphene, tremendous efforts have been made over the past decade to fabricate conducting polymer and CNT composites with an aim of synergistically combining the merits of each individual components. In this thesis, a series of novel conducting polymer nanocomposites with these remarkable carbon nanomaterials will be designed and developed with an ultimate goal of sensitive and selective detection of warfare agents for homeland security and low-cost metal free electrocatalysts for fuel cell applications. Experimental results demonstrate that the composite shows dramatically improved performance compared to each of the individual components. The results obtained from these studies combined with an introduction of the state of the art of the development in this field and future prospects will be presented through 6 chapters of this thesis.Ph. D.Includes bibliographical referencesIncludes vitaBy Rishi R. Parajul
Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal
No full textScrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country
Diagnostic evaluation of IgM ELISA and IgM Immunofluorescence assay for the diagnosis of Acute Scrub Typhus in central Nepal
No full textBACKGROUND: Scrub typhus is an acute febrile illness caused by the obligate intracellular bacterium, Orientia tsutsugamushi. Immunochromatography (ICT) and IgM ELISA are two of the routinely employed antibody based assays for diagnosis of Scrub typhus fever in Nepal, although the recommended gold standard diagnostic test is IgM Immunofluorescence assay (IFA). This study evaluated InBios Scrub Typhus Detect™ Immunoglobulin M (IgM) ELISA and IgM Immunofluorescence assays in single serum sample at the time of admission. METHOD: Study participants (1585 suspected cases), were enrolled based on acute febrile illness with suspected scrub typhus cases in central Nepal. Blood sample was collected from the suspected patients of scrub typhus, presenting with acute febrile illness. IgM antibody to Orientia tsusugamushi was detected by using Scrub Typhus Detect™ Kit and an in-house IgM IFA. The IFA assay was performed with the Gilliam, Karp, Kato strains and O. chuto antigens following the ARRL protocol. RESULT: Statistical analysis of IgM ELISA results when compared to reference test, IgM IFA results demonstrated the following characteristics, sensitivity 84.0% (95%CI: 79.73-87.68%), specificity 94.82% (95% CI: 93.43-95.99%), positive likelihood ratio 16.21% (95% CI: 12.71-20.67%), negative likelihood ratio 0.17% (95% CI: 0.13-0.21%), disease prevalence 22.08% (95% CI: 20.06 -24.21%), positive predictive value 82.12% (95% CI: 78.28-85.42%) and negative predictive value 95.44% (95% CI: 94.27-96.38%) respectively. CONCLUSION: Although IgM IFA is considered the gold standard test for the diagnosis of scrub typhus cases, it is relatively expensive, requires trained personal and a microscope with fluorescence filters. Scrub typhus IgM ELISA may be the best alternative test and possible viable option for resource limited endemic countries like Nepal.Full Tex
Authorship in Medical Literature
No full textScientific paper publication has an important role in the academic filed. Being an author of such paper based on the research or other scholarly activity is associated with many benefits such as peer recognition, financial gain, promotion, job appointment, and fellowship and research awards. The race to increase the quantity rather than the quality of manuscript among the researchers has made the researchers being involved in an unethical practice. To be included as an author one must fulfill the authorship criteria developed by the International Committee of Medical Journal Editors (ICMJE). One shouldn’t be given credit for authorship who can’t defend the published work. Authorship misuse in the form of gift authorship, guest authorship or ghost authorship is not uncommon these days. To reduce the authorship conflicts many journals have set strict policy to mention about the nature of the contribution made by each “author” and that information is available to the readers.</jats:p
Aminomethylphosphonic Acid and Methoxyacetic Acid Induce Apoptosis in Prostate Cancer Cells
No full textAminomethylphosphonic acid (AMPA) and its parent compound herbicide glyphosate are analogs to glycine, which have been reported to inhibit proliferation and promote apoptosis of cancer cells, but not normal cells. Methoxyacetic acid (MAA) is the active metabolite of ester phthalates widely used in industry as gelling, viscosity and stabilizer; its exposure is associated with developmental and reproductive toxicities in both rodents and humans. MAA has been reported to suppress prostate cancer cell growth by inducing growth arrest and apoptosis. However, it is unknown whether AMPA and MAA can inhibit cancer cell growth. In this study, we found that AMPA and MAA inhibited cell growth in prostate cancer cell lines (LNCaP, C4-2B, PC-3 and DU-145) through induction of apoptosis and cell cycle arrest at the G1 phase. Importantly, the AMPA-induced apoptosis was potentiated with the addition of MAA, which was due to downregulation of the anti-apoptotic gene baculoviral inhibitor of apoptosis protein repeat containing 2 (BIRC2), leading to activation of caspases 7 and 3. These results demonstrate that the combination of AMPA and MAA can promote the apoptosis of prostate cancer cells, suggesting that they can be used as potential therapeutic drugs in the treatment of prostate cancer
Statewide Customer Service and Hospitality Training
No full textBetween November 2005 and February 2006, Utah State University’s Institute for Outdoor Recreation and Tourism (IORT) conducted an internet-based survey of Utah tourism business owners, operators, and managers, as well as others involved with tourism-related organizations
Comparative evaluation of microscopy and polymerase chain reaction (PCR) for the diagnosis in suspected malaria patients of Nepal
No full textto compare the efficiency of microscopy and PCR for malaria diagnosis in Nepalese context. During July-August 2007, blood samples were collected in glass slides and on filter papers from suspected malaria cases of Kanchanpur, Jhapa and Morang Districts. Sample transportation and storage was done using standard protocol. Microscopy was done at the heath posts in the district in Nepal while Nested PCR using previously standardized primers was carried out at Mahidol University. Among 824 malaria suspected cases, 19.2
Epidemiology, Risk Factors and Seasonal Variation of Scrub Typhus Fever in Central Nepal
No full textScrub typhus is a mite-borne acute febrile illness caused by Orientia. tsutsugamushi, a zoonotic bacterial infection common in the region known as the tsutsugamushi triangle. This study aims to determine the seroprevalence, seasonal variation, and risk factors of scrub typhus among the acute febrile illness patients attending different hospitals of central Nepal. Blood samples were collected from hospitalized patients of acute febrile illness suspected of scrub typhus infection attending different hospitals of central Nepal from April 2017 to March 2018. The IgM antibody to Orientia tsutsugamushi was detected by using the Scrub Typhus Detect™ Kit. Among the total cases (1585), 358 (22.58%) were positive for IgM Antibodies. Multivariate analysis identified several risks factors to be significantly associated with the scrub typhus infection, including gender (female) (odds ratio [OR] = 1.976, p ≤ 0.001, confidence interval [CI] = 1.417⁻2.756), rural residential location (odds ratio [OR] = 0.431, p = 0.001, confidence interval [CI] = 0.260⁻0.715), house near grassland (odds ratio [OR] = 3.288, p ≤ 0.001, confidence interval [CI] = 1.935⁻5.587), and working in the field (odds ratio [OR] = 9.764, p = 0.004, confidence interval [CI] = 2.059⁻46.315). The study findings indicate scrub typhus infection to be a significant health problem in Nepal. The proper diagnosis of infection cases, timely institution of therapy, public awareness, and vector control are important measures to be taken for the prevention and management of scrub typhus
- …
