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Eigenvalues of the matching derangement graph
No full textIn this paper, we derive a formula for the eigenvalues of the matching derangement graph. The formula gives an insight regarding the alternating sign conjecture for the eigenvalues of the matching derangement graph. In particular, we show that the alternating sign property holds for certain partitions
Alstoscholactine and Alstolaxepine, Monoterpenoid Indole Alkaloids with γ-Lactone-Bridged Cycloheptane and Oxepane Moieties from Alstonia scholaris
No full textTwo new monoterpenoid indole alkaloids, alstoscholactine (1) and alstolaxepine (2), were isolated from Alstonia scholaris. Compound 1 represents a rearranged stemmadenine alkaloid with an unprecedented C-6-C-19 connectivity, whereas compound 2 represents a 6,7-seco-angustilobine B-type alkaloid incorporating a rare γ-lactone-bridged oxepane ring system. Their structures and absolute configurations were determined by spectroscopic analyses. Compound 1 was successfully semisynthesized from 19E-vallesamine. Compound 2 induced marked vasorelaxation in rat isolated aortic rings precontracted with phenylephrine
Development of a Novel Hydrophobic ZrO2–SiO2 Based Acid Catalyst for Catalytic Esterification of Glycerol with Oleic Acid
No full textThe inevitably low value of glycerol has led to extensive investigations on glycerol conversion to value-added derivatives. The esterification of glycerol with oleic acid is currently a very important industrial process. In this work, a novel heterogeneous acid catalyst featuring hydrophobic surface is developed on modified ZrO2-SiO2 support as water-tolerant solid acid catalyst is vital for biphasic esterification reactions that produce water. The novel ZrO2-SiO2-Me&Et-PhSO3H catalyst was prepared through silication and surface modification with trimethoxymethylsilane and 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane. This work showed that it is possible to control the acidity and hydrophobicity of the catalyst by tailoring the amount of surface modification agents. It was found that the hydrophobicity of the catalyst decreased as its acidity increased. Furthermore, at constant catalyst acidity, the more hydrophobic catalyst showed a better yield
Seroprevalence of Q Fever Among the Indigenous People (Orang Asli) of Peninsular Malaysia
No full textQ fever is a disease caused by Coxiella burnetii. It is a disease of public health concern in many parts of the world. In this study, we described the seroprevalence of Q fever among selected populations of Orang Asli (OA), indigenous people, many of whom live within the forest fringe areas of Peninsular Malaysia. Serum samples were obtained from 887 OA participants from selected villages. Samples were analyzed for the presence of IgG antibodies reactive against C. burnetii by enzyme-linked immunosorbent assay. Statistical methods were used to identify possible associations between seropositivity for C. burnetii and a number of demographic variables obtained from the questionnaires. In total, 9.6% (n = 85/887) of the serum samples were reactive to C. burnetii. Statistical results suggest that elderly male OA residing in OA village, Bukit Payung, were most likely to be tested seropositive for C. burnetii. This study suggests that OA are at a significant risk of contracting C. burnetii infection, and both demographic and geographic factors are important contributors to this risk. Further prospective studies are needed to establish the true burden of C. burnetii infection within the indigenous population as well as within Peninsular Malaysia as a whole
Complete chromosome and plasmid sequences of two plant pathogens, Dickeya solani strains D s0432-1 and PPO 9019
No full textDickeya solani species are emerging bacterial pathogens of Solanum tuberosum. Here, we announce the complete genome sequences of two strains, Dickeya solani D s0432-1 and PPO 9019. Strain PPO 9019 represents the first described member of the genus Dickeya with an extrachromosomal genetic element
Green maintenance for heritage buildings: Low carbon laterite stones repair appraisal
No full textSustainability commonly denotes an integration of economic, environmental and societal domains. Low carbon repair of buildings also conforms to these broad domains. Environmental consideration in low carbon repair appraisal for heritage buildings has become increasingly important and this paper supports this expanding area. This paper gives an insight on how 'Green Maintenance' concept and methodology practically determine and ultimately substantiate appraisal on low carbon repair for laterite stones of selected multiple case studies of heritage buildings located at Historical City of Melaka, Malaysia. This paper also provides highlights of comparative study and analysis of these case study buildings on their common techniques and materials for laterite stones repair. This has been achieved through quantification of embodied carbon expenditure expended in laterite stones repair within 'cradle-to-site' boundary of Life Cycle Assessment (LCA) using formulaic expression and calculation procedure of 'Green Maintenance' model. The calculation procedures of the model were adopted to enable evaluation of CO2 emissions in terms of embodied carbon expenditure expended from laterite stones repair for selected case studies during maintenance phase. It is found that stone replacement technique is considered as the most sustainable repair technique, mainly due to its high longevity of repair, in terms of generated Environmental Maintenance Impact (EMI) of Green Maintenance modelling. More importantly, EMI of the model relays the true value of CO2 emissions contextualised within the longevity of repair and minimal intervention that allow low carbon repair appraisal approach
Characterization and potential roles of bone marrow-derived stromal cells in cancer development and metastasis
No full textBackground: The tumor microenvironment and its stromal cells play an important role in cancer development and metastasis. Bone marrow-derived cells (BMDCs), a rich source of hematopoietic and mesenchymal stem cells, putatively contribute to this tumoral stroma. However their characteristics and roles within the tumor microenvironment are unclear. In the present study, BMDCs in the tumor microenvironment were traced using the green fluorescent protein (GFP) bone marrow transplantation model. Methods: C57BL/6 mice were irradiated and rescued by bone marrow transplantation from GFP-transgenic mice. Lewis lung cancer cells were inoculated into the mice to generate subcutaneous allograft tumors or lung metastases. Confocal microscopy, immunohistochemistry for GFP, α-SMA, CD11b, CD31, CD34 and CD105, and double-fluorescent immunohistochemistry for GFP-CD11b, GFP-CD105 and GFP-CD31 were performed. Results: Round and dendritic-shaped GFP-positive mononuclear cells constituted a significant stromal subpopulation in primary tumor peripheral area (PA) and metastatic tumor area (MA) microenvironment, thus implicating an invasive and metastatic role for these cells. CD11b co-expression in GFP-positive cells suggests that round/dendritic cell subpopulations are possibly BM-derived macrophages. Identification of GFP-positive mononuclear infiltrates co-expressing CD31 suggests that these cells might be BM-derived angioblasts, whereas their non-reactivity for CD34, CD105 and α-SMA implies an altered vascular phenotype distinct from endothelial cells. Significant upregulation of GFP-positive, CD31-positive and GFP/CD31 double-positive cell densities positively correlated with PA and MA (P<0.05). Conclusion: Taken together, in vivo evidence of traceable GFP-positive BMDCs in primary and metastatic tumor microenvironment suggests that recruited BMDCs might partake in cancer invasion and metastasis, possess multilineage potency and promote angiogenesis
Short-pulsed Q-switched Thulium doped fiber laser with graphene oxide as a saturable absorber
No full textThis paper reports a generation of short-pulsed thulium-doped fiber laser (TDFL) in Q-switching operation incorporation of homemade graphene oxide (GO) saturable absorber (SA). The GO SA is embedded with a polymer to form a GO film. A piece of the GO film is integrated into the TDFL cavity for generating a self-started Q-switching operation at 1943 nm wavelength. The 3-dB bandwidth, repetition rate, and pulse width of the laser are obtained as 9 nm, 15.76 kHz–25.08 kHz, and 5.08 μs–4.2 μs, respectively. The maximum pulse energy of 0.698 μJ obtainable at 344 mW pump power, with a peak power of 137.4 mW. With a shortest pulse width size at a maximum pump power of 491 mW, the higher peak power is determined about 162 mW. By integrating our stable Q-switched laser with an optical amplifier, numerous applications such as a material cutting with the eye-safe feature can be realized. This shows a small piece of the GO can modulate a light and use for the pulsed laser industry
18s rDNA Sequence Analysis of Microfungi from Biofloc-based System in Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture
No full textBackground and Objective: One of the major problem in Pacific Whiteleg shrimp, Litopenaeus vannamei farming industry is the accumulation of excess toxicant such as ammonia and nitrite. Biofloc technology served as an alternative solution to solve this problem by recycling the water for sustainable aquaculture management due to water scarcity, bio-security and bio-economy. Biological communities within biofloc are mainly composed of micro-organisms which plays an important role in biodegradation of organic material and removal of toxic contaminants. For the purpose of this study, molecular identification of microfungi isolated from biofloc was conducted. Materials and Methods: Isolation of microfungi composition was conducted by culturing the biofloc samples onto Potato Dextrose Agar (PDA) media which further identified molecularly using 18s rDNA sequences analysis. Results: The identified microfungi includes genus from Aspergillus versicolor, A. Niger, A. tamarii, A. flavipes, A. aculeatus, Penicillium citrinum, P. griseofulvum, Trichoderma virens and Pestalotiopsis microspora. The most dominant microfungi were genus Aspergillus sp. followed by the presence of Penicillium sp. Trichoderma sp. and Pestalotiopsis sp. Conclusion: Existence of microfungi species such as Aspergillus sp. and Penicillium sp. in biofloc were perfect candidate in forming biofloc that could reduce water pollution towards a sustainable aquaculture industry
Expression and DNA methylation of MET1, CMT3 and DRM2 during in vitro culture of Boesenbergia rotunda (L.) Mansf.
No full textSomatic embryogenesis and plant regeneration are important developmental processes of in vitro culture, in which cells must undergo dedifferentiation, activation of cell division and reprograming of their metabolism, of their physiology and of their gene expression patterns. The processes of somatic embryogenesis and plant regeneration are also associated with changes in DNA methylation. In this study, the expression of METHYLTRANSFERASE 1, CHROMOMETHYLASE 3 and DOMAIN REARRANGED METHYLTRANSFERASE 2 was determined by Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) while the DNA methylation level was determined by Bisulfite sequencing of plant cells from meristematic block, embryogenic and non-embryogenic calli, prolonged cell suspension culture, ex vitro leaf and in vitro leaf of regenerated plants of Boesenbergia rotunda. We observed that the expression of DNA methyltransferase genes METHYLTRANSFERASE 1, CHROMOMETHYLASE 3 and DOMAIN REARRANGED METHYLTRANSFERASE 2 was the highest in meristematic block followed by embryogenic callus, and the lowest was in watery callus. DNA methylation at CG, CHG and CHH sequence contexts was observed to be generally lower in embryogenic callus than in other samples. We observed relatively higher expression levels and lower levels of DNA methylation at CG, CHG and CHH sequence contexts of MET1, CMT3 and DRM2 associated with somatic embryogenesis and regenerability in Boesenbergia rotunda