3,006 research outputs found
Interplay of chemical pressure and hydrogen insertion effects in from first principles
Investigations within the local spin density functional theory (LSDF) of the
intermetallic hydride system were carried out for discrete
model compositions in the range . The aim of this
study is to assess the change of the cerium valence state in the neighborhood
of the experimental hydride composition, . In agreement
with experiment, the analyses of the electronic and magnetic structures and of
the chemical bonding properties point to trivalent cerium for . In contrast, for lower hydrogen amounts the hydride system stays in an
intermediate-valent state for cerium, like in . The influence
of the insertion of hydrogen is addressed from both the volume expansion and
chemical bonding effects. The latter are found to have the main influence on
the change of Ce valence character. Spin polarized calculations point to a
finite magnetic moment carried by the Ce states; its magnitude increases
with in the range
Comparative profiling of biomarker psoralen in antioxidant active extracts of different species of genus Ficus by validated HPTLC method
Background: A simple but sensitive HPTLC method was developed for the comparative evaluation of psoralen in antioxidant active extracts of leaves of five different species of genus Ficus (Ficus carica, Ficus nitida, Ficus ingens, Ficus palmata and Ficus vasta).Materials and Methods: HPTLC studies were carried out using CAMAG HPTLC system on Glass-backed silica gel 60F254 HPTLC pre-coated plates using selected mobile phase toluene: methanol (9:1). The antioxidant activity was carried out, using DPPH free radical method.Results: Among all the five species of genus Ficus, F. palmata and F. carica exhibited comparatively good antioxidant activity in DPPH assay. The developed HPTLC method was found to give a compact spot for psoralen (Rf = 0.55±0.001) at 305 nm. The regression equation and r2 for psoralen was found to be Y= 4.516X+35.894 and 0.998. The quantification result revealed the presence of psoralen in only two species, F. carica (0.24%, w/w) and F. palmata (1.88%, w/w) which supported their supremacy for anti-oxidant potential over other species. The statistical analysis proved that the developed method was reproducible and selective.Conclusion: The developed method can be used as an important tool to assure the therapeutic dose of active ingredients in herbal formulations as well as for standardization and quality control of bulk drugs and in-process formulations. This method can also be employed for the further study of degradation kinetics and determination of psoralen in plasma and other biological fluids.Key words: Ficus species, psoralen, antioxidant, HPTLC, Validation
First principles investigations of the electronic, magnetic and chemical bonding properties of CeTSn (T=Rh,Ru)
The electronic structures of CeRhSn and CeRuSn are self-consistently
calculated within density functional theory using the local spin density
approximation for exchange and correlation. In agreement with experimental
findings, the analyses of the electronic structures and of the chemical bonding
properties point to the absence of magnetization within the mixed valent Rh
based system while a finite magnetic moment is observed for trivalent cerium
within the Ru-based stannide, which contains both trivalent and intermediate
valent Ce.Comment: 6 pages, 7 figures, for more information see
http://www.physik.uni-augsburg.de/~eyert
Trends in Seagrass Research and Conservation in Malaysian Waters
The seagrass ecosystems found in the marine and coastal areas, with substantial economic and ecological services and span all over the globe excluding the Antarctic region. The Coral Triangle and Southeast Asia are recognized as a worldwide hotspot of seagrass species and habitats, encompassing 10-21 species of seagrass in every nation, although the study, understanding, and quantity of publications on seagrass ecosystems are rather limited in the region, including Malaysia. Malaysia contains 18 seagrass species from three families, which occupy 16.8 km2 of coastal area, where the study and discovery of seagrass species and meadows began in 1904 with the report of Beccari. All of the published papers reviewed reported on Malaysian seagrass-related research, which was divided into nine topic groups: biology and distribution, carbon sequestration, fauna, remote sensing, impact and pollution genetic study, restoration, microbiological investigation, and others. The extensive study of the seagrass ecosystem began in 1993, and we have identified 183 published papers from Scopus, 141 publications from Web of Science, and 42 from Google Scholar. However, the average trend of the number of publications from 1993 to 1999 was 0.71 ± 0.36, while from 2000 to 2022 was 7.70 ± 1.16 followed by the average trend of the yearly number of publications was 6.78 ± 1.08. The highest number of publications was found on faunal categories (43.17%), followed by biology and distribution (21.85%). The number of articles that were published on Malaysian seagrass meadows each year has been discovered to be rising, which indicates that the trends in seagrass study and publishing were progressively garnering the attention of researchers, academics, and the government. However, to better understand the sustainable ecology and ecosystem services provided by seagrass habitats, an emphasis on certain research niches, such as the genetic study of flora and fauna in seagrass meadows, microbial ecology, and restoration as well as conservation of seagrass species might be helpful.22 página
Non-factorizable long distance contributions in color suppressed decays of B mesons
, , and decays are
studied. Their amplitude is given by a sum of factorized and non-factorizable
ones. The latter which is estimated by using a hard pion approximation is
rather small in color favored and decays but still
can efficiently interfere with the main amplitude given by the factorization.
In the color suppressed and decays, the
non-factorizable contribution is very important. The sum of the factorized and
non-factorizable amplitudes can reproduce well the existing experimental data
on the branching ratios for the color favored and
and the color suppressed and decays by
taking reasonable values of unknown parameters involved.Comment: 19 pages, Revte
The inherent tensions within sustainable supply chains: a case study from Bangladesh
The complexities surrounding the supply chain logistics for perishable commodities within Bangladesh are extensive. Poor infrastructure, fragmented transportation and corruption compound the operational complexities within this emerging market. This case study analyses many of the day-to-day operational challenges and tensions inherent within Micro-Small-Medium Enterprises (MSMEs) forming the backbone of the Bangladesh socio-economic structure. The drive for transition toward greater levels of sustainability and corporate responsibility is problematic, affecting many levels within an extended and fragmented supply chain. The selected case study highlights the “lived in” geographical, environmental, economic and cultural factors that impact the ability of emerging market enterprises to remain profitable within emergency scenarios whilst transitioning toward a more sustainable model. This study, whilst detailing many of the tensions and critical issues facing MSMEs, highlights the benefits of direct Government intervention, criticality of a leaner and more efficient supply chain and reassessment of financial incentives to drive the transition to a more efficient and sustainable economy
Genetic, serological and biochemical characterization of Leishmania tropica from foci in northern Palestine and discovery of zymodeme MON-307
Background
Many cases of cutaneous leishmaniasis (CL) have been recorded in the Jenin District based on their clinical appearance. Here, their parasites have been characterized in depth.
Methods
Leishmanial parasites isolated from 12 human cases of CL from the Jenin District were cultured as promastigotes, whose DNA was extracted. The ITS1 sequence and the 7SL RNA gene were analysed as was the kinetoplast minicircle DNA (kDNA) sequence. Excreted factor (EF) serotyping and multilocus enzyme electrophoresis (MLEE) were also applied.
Results
This extensive characterization identified the strains as Leishmania tropica of two very distinct sub-types that parallel the two sub-groups discerned by multilocus microsatellite typing (MLMT) done previously. A high degree of congruity was displayed among the results generated by the different analytical methods that had examined various cellular components and exposed intra-specific heterogeneity among the 12 strains.
Three of the ten strains subjected to MLEE constituted a new zymodeme, zymodeme MON-307, and seven belonged to the known zymodeme MON-137. Ten of the 15 enzymes in the profile of zymodeme MON-307 displayed different electrophoretic mobilities compared with the enzyme profile of the zymodeme MON-137. The closest profile to that of zymodeme MON-307 was that of the zymodeme MON-76 known from Syria.
Strains of the zymodeme MON-307 were EF sub-serotype A2 and those of the zymodeme MON-137 were either A9 or A9B4. The sub-serotype B4 component appears, so far, to be unique to some strains of L. tropica of zymodeme MON-137. Strains of the zymodeme MON-137 displayed a distinctive fragment of 417 bp that was absent in those of zymodeme MON-307 when their kDNA was digested with the endonuclease RsaI. kDNA-RFLP after digestion with the endonuclease MboI facilitated a further level of differentiation that partially coincided with the geographical distribution of the human cases from which the strains came.
Conclusions
The Palestinian strains that were assigned to different genetic groups differed in their MLEE profiles and their EF types. A new zymodeme, zymodeme MON-307 was discovered that seems to be unique to the northern part of the Palestinian West Bank. What seemed to be a straight forward classical situation of L. tropica causing anthroponotic CL in the Jenin District might be a more complex situation, owing to the presence of two separate sub-types of L. tropica that, possibly, indicates two separate transmission cycles involving two separate types of phlebotomine sand fly vector
Effects of Nigella sativa and Lepidium sativum on Cyclosporine Pharmacokinetics
The present study was conducted to investigate the effects of Nigella sativa and Lepidium sativum on the pharmacokinetics of cyclosporine in rabbits. Two groups of animals were treated separately with Nigella sativa (200 mg/kg p.o.) or Lepidium sativum (150 mg/kg p.o.) for eight consecutive days. On the 8th day, cyclosporine (30 mg/kg p.o.) was administered to each group one hour after herbal treatment. Blood samples were withdrawn at different time intervals (0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12, and 24 hrs) from marginal ear vein. Cyclosporine was analyzed using UPLC/MS method. The coadministration of Nigella sativa significantly decreased the max and AUC 0−∞ of cyclosporine; the change was observed by 35.5% and 55.9%, respectively ( ≤ 0.05). Lepidium sativum did not produce any significant change in max of cyclosporine, although its absorption was significantly delayed compared with control group. A remarkable change was observed in max and AUC 0− of Lepidium sativum treated group. Our findings suggest that concurrent consumption of Nigella sativa and Lepidium sativum could alter the pharmacokinetics of cyclosporine at various levels
Malaria mortality in Africa and Asia: evidence from INDEPTH health and demographic surveillance system sites
This paper is part of the Special Issue: INDEPTH Network Cause-Specific Mortality.
A Corrigendum has been published for this paper. Please see http://www.globalhealthaction.net/index.php/
gha/article/view/27833Malaria continues to be a major cause of infectious disease mortality in tropical regions. However, deaths from malaria are most often not individually documented, and as a result overall understanding of malaria epidemiology is inadequate. INDEPTH Network members maintain population surveillance in Health and Demographic Surveillance System sites across Africa and Asia, in which individual deaths are followed up with verbal autopsies.To present patterns of malaria mortality determined by verbal autopsy from INDEPTH sites across Africa and Asia, comparing these findings with other relevant information on malaria in the same regions.From a database covering 111,910 deaths over 12,204,043 person-years in 22 sites, in which verbal autopsy data were handled according to the WHO 2012 standard and processed using the InterVA-4 model, over 6,000 deaths were attributed to malaria. The overall period covered was 1992-2012, but two-thirds of the observations related to 2006-2012. These deaths were analysed by site, time period, age group and sex to investigate epidemiological differences in malaria mortality.Rates of malaria mortality varied by 1:10,000 across the sites, with generally low rates in Asia (one site recording no malaria deaths over 0.5 million person-years) and some of the highest rates in West Africa (Nouna, Burkina Faso: 2.47 per 1,000 person-years). Childhood malaria mortality rates were strongly correlated with Malaria Atlas Project estimates of Plasmodium falciparum parasite rates for the same locations. Adult malaria mortality rates, while lower than corresponding childhood rates, were strongly correlated with childhood rates at the site level.The wide variations observed in malaria mortality, which were nevertheless consistent with various other estimates, suggest that population-based registration of deaths using verbal autopsy is a useful approach to understanding the details of malaria epidemiology.P. Kim Streatfield ... Yohannes A. Melaku ... et. al
- …