177 research outputs found
Non-Linear Dynamics and Critical Phenomena in the Holographic Landscape of Weyl Semimetals
This study presents a detailed analysis of critical phenomena in a
holographic Weyl semi-metal (WSM) using the brane configuration. The
research explores the non-linear response of the longitudinal current
when subjected to an external electric field at both zero and finite
temperatures. At zero temperature, the study identifies a potential quantum
phase transition in the - relationship, driven by background
parameters the particle mass, and axial gauge potential. This transition is
characterized by a unique reconnection phenomenon resulting from the interplay
between WSM-like and conventional nonlinear conducting behaviors, indicating a
quantum phase transition.
Additionally, at non-zero temperature with dissipation, the system
demonstrates first- and second-order phase transitions as the electric field
and axial gauge potential are varied. The longitudinal conductivity is used as
an order parameter to identify the current-driven phase transition. Numerical
analysis reveals critical exponents in this non-equilibrium phase transition
that show similarities to mean-field values observed in metallic systems.Comment: typo correcte
Heat capacities and thermodynamic geometry in deformed Jackiw-Teitelboim gravity
We study the thermodynamics of charged AdS black holes in deformed
Jackiw-Teitelboim (dJT) gravity and their phase structures. In this regard, we
will find some critical values for the temperature, entropy and charge of the
corresponding black holes. We also compute the heat capacities, expansion
coefficient and isothermal compressibility as thermodynamic response functions
and study their behaviors at the critical points. It will be shown that these
variables satisfy the Ehrenfest's equations in the case of second-order phase
transition. We employ different formalisms to investigate thermodynamic
geometry, such as Weinhold, Ruppeiner and new thermodynamic geometry, then
analyze the singularities of the thermodynamic curvatures in this context. We
show that these singularities are also correspond to the divergences of the
response functions which indicating the critical points of phase transitions.Comment: 19 pages, 10 figures,refs added, improved versio
Planar Black Holes in Holographic Axion Gravity: Islands, Page Times, and Scrambling Times
The present work investigates the entanglement entropies of the Hawking
radiations, the Page times, and the scrambling times, for the eternal planar
black holes in the holographic axion gravity. The solutions correspond to a new
class of charged black holes, because the boundary diffeomorphism is broken due
to the graviton mass induced by the axion fields in the bulk. The information
theoretical aspects of these black hole solutions is determined upon applying
the island rule for the entanglement entropy. Like non-extremal charged black
holes, the radiation entropy grows linearly in the no-island configurations,
while is saturated at late times by asymptotic values set by the
Bekenstein-Hawking entropy in the island configurations, with the boundary
being located slightly outside the outer horizon. In particular, for the
extremal black planes of holographic axion gravity, we find that: (a) the
entanglement entropy of the Hawking radiation is ill-defined at the early times
when the island is absent; (b) it tends to a distinctive constant at the late
times; (c) the late-time location of the island is indeed universal. Moreover,
we investigate how the Page time is affected by the holographic massive gravity
deformation. For neutral solutions at the small deformation parameter, and for
charged solutions with almost-extremal deformation parameter, we find that the
Page transition happens at earlier times.Comment: 12 pages, 1 table, 3 figures, references added, accepted by PR
Genetic Diversity and Phylogenetic Study of Leishmania Species in Iran by Multilocus Sequence Typing
Background: Leishmaniasis is an important public health parasitic infection, which is endemic in many parts of the world, including Iran. We aimed to investigate genetic diversity and phylogenetic relationship among different Leishmania isolates using multilocus sequence typing (MLST).
Methods: Totally, 41 isolates collected either from patients referred to Leishmaniasis Diagnostics and Treatment Center at Tehran University of Medical Sciences, Tehran, Iran or from animals during 2019-2021, were subjected to the study. They included L. major and L. tropica from human, L. infantum from canine, and L. turanica from rodents from different endemic foci of Iran analyzed using MLST including gp63, g6pdh, lack, nagt, and hsp70 genes.
Results: A total of 5010 bps was analyzed from each isolate. The three targets, nagt, lack, and g6pdh, generated better topology comparing to the other genes. In the 44 isolates, 22 haplotypes (STs) were identified. Leishmania tropica contained the highest number of haplotypes (n=12) comparing to L. major (n=8), L. infantum (n=1) and L. turanica (n=1). All five genomic loci caused separation of Iranian Leishmania species at the species level, indicating conservation of these genes in the Leishmania parasite.
Conclusion: The highest number of haplotypes belonged to L. tropica, indicating that the genetic diversity of this species is higher than that of L. major. It was further confirmed that the MLST is a suitable method to examine genetic variation of Leishmania parasites with respect to evolutionary and epidemiological studies.publishedVersio
Isolation and Molecular Identification of Vahlkampfiidae and Vermamoeba Vermiformis from Fresh Vegetables: A Neglected Source of Infections
Background: Naegleria spp., Tetramitus spp., and Vermamoeba vermiformis are potential pathogenic free-living amoebae (FLA) causing diseases such as keratitis, meningoencephalitis, and lung infections. We aimed to investigate the presence of Vahlkampfiidae and V. vermiformis in raw vegetables commonly consumed in Iran.
Methods: Totally, 70 samples of vegetables samples including watercress (22), leeks (12), parsley (10), basil (13) and mint (13) were collected from municipal markets of Tehran, the capital of Iran during June to October 2021. After washing vegetables, samples were cultivated onto 2% non-nutrient agar (NNA) medium. After morphological confirmations, DNA was extracted and identical fragments of the FLA were amplified and sequenced.
Results: Out of 70 cultured samples, 11 samples (15.71 %) were morphologically positive, of which four and seven were V. vermiformis and Vahlkampfiidae isolates, respectively. According to the PCR/sequencing results two, one, one, and one strains belonged to N. australiensis, N. americana, Vahlkampfia sp., V. inornata, and T. aberdonicus, respectively. All Vermamoeba genus were characterized as V. vermiformis.
Conclusion: The results of current study revealed the contamination of fresh raw vegetables with Vahlkampfiidae and V. vermiformis. In addition, to our knowledge this is the first report of T. aberdonicus in raw vegetables. Our findings highlight the public health importance of vegetables in transmission of FLA, as well as the potential role of FLA in transmission of potential pathogenic microorganisms via consuming of fresh raw vegetables
Evolutionary and phylogenetic analyses of the barcoding region suggest geographical relationships among Blastocystis sp., ST3 in humans
publishedVersio
Genetic Diversity and Phylogenetic Study of Leishmania Species in Iran by Multilocus Sequence Typing
Background: Leishmaniasis is an important public health parasitic infection, which is endemic in many parts of the world, including Iran. We aimed to investigate genetic diversity and phylogenetic relationship among different Leishmania isolates using multilocus sequence typing (MLST).
Methods: Totally, 41 isolates collected either from patients referred to Leishmaniasis Diagnostics and Treatment Center at Tehran University of Medical Sciences, Tehran, Iran or from animals during 2019-2021, were subjected to the study. They included L. major and L. tropica from human, L. infantum from canine, and L. turanica from rodents from different endemic foci of Iran analyzed using MLST including gp63, g6pdh, lack, nagt, and hsp70 genes.
Results: A total of 5010 bps was analyzed from each isolate. The three targets, nagt, lack, and g6pdh, generated better topology comparing to the other genes. In the 44 isolates, 22 haplotypes (STs) were identified. Leishmania tropica contained the highest number of haplotypes (n=12) comparing to L. major (n=8), L. infantum (n=1) and L. turanica (n=1). All five genomic loci caused separation of Iranian Leishmania species at the species level, indicating conservation of these genes in the Leishmania parasite.
Conclusion: The highest number of haplotypes belonged to L. tropica, indicating that the genetic diversity of this species is higher than that of L. major. It was further confirmed that the MLST is a suitable method to examine genetic variation of Leishmania parasites with respect to evolutionary and epidemiological studies
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
Can Giardia Infection Impair the Diagnostic Level of Fecal Calprotectin in Patients with Inflammatory Bowel Disease? A Case Report
Inflammatory bowel disease (IBD) is attributed to complex conditions of gastrointestinal tract that is frequently reported all over the world. Fecal calprotectin evaluation is described as a primary tool to screen IBD patients. There are reports showing the confounding role of some microbial agents in diagnostic levels of calprotectin. A 32-yr-old woman with symptoms like IBD/IBS (irritable bowel syndrome); admitted to IBD Clinic of Behbood Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Jan 2017 for evaluation of the level of fecal calprotectin. In spite of high level of calprotectin, trophozoite of Giardia intestinalis was observed in direct examination of stool sample. Microbial pathogens can lead to false elevation of fecal calprotectin and misdiagnosis of gastrointestinal patients suspected to IBD
Gastrointestinal Parasites of Domestic Mammalian Hosts in Southeastern Iran
Gastrointestinal parasites (GIP) are a major cause of disease and production loss in livestock. Some have zoonotic potential, so production animals can be a source of human infections. We describe the prevalence of GIP in domestic mammals in Southeastern Iran. Fresh fecal samples (n = 200) collected from cattle (n = 88), sheep (n = 50), goats (n = 23), camels (n = 30), donkeys (n = 5), horse (n = 1), and dogs (n = 3) were subjected to conventional coprological examination for the detection of protozoan (oo)cysts and helminth ova. Overall, 83% (166/200) of the samples were positive for one or more GIP. Helminths were found in dogs, donkeys, sheep (42%), camels (37%), goats (30%), and cattle (19%), but not in the horse. Protozoa were found in cattle (82%), goats (78%), sheep (60%), and camels (13%), but not in donkeys, dogs, or the horse. Lambs were 3.5 times more likely to be infected by protozoa than sheep (OR = 3.5, 95% CI: 1.05-11.66), whereas sheep were at higher odds of being infected by helminths than lambs (OR = 4.09, 95% CI: 1.06-16.59). This is the first study assessing the prevalence of GIP in domestic mammals in Southeastern Iran.This research was funded by the Office of Vice-chancellor for Research of Iranshahr University of Medical Sciences (Grant No. 9900039) and within the scope of the project CICECOAveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC).S
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