93 research outputs found
Antibiotic susceptibility evaluation of group a streptococcus isolated from children with pharyngitis: A study from Iran
Background: The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children. Materials and Methods: From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children's Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods. Results: From 200 children enrolled in this study, 59 (30) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9, 57.6, and 33.9, respectively. Surprisingly, 8.4 of GAS strains were resistant to rifampin. In this study, 13.5 and 32.2 of the strains were resistant to clindamycin and ofloxacin, respectively. Conclusion: The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment. © 2015 by The Korean Society of Infectious Diseases | Korean Society for Chemotherapy
Prevalence of Zoonotic Intestinal Helminths of Canids in Moghan Plain, Northwestern Iran
Background: The present study was aimed to elucidate the status of intestinal helminth infections in canids of Moghan Plain, northwestern Iran.Methods: Eighty-five intestine samples from dead or shot wild canids, 59 fecal samples from sheepdogs and 5 from red foxes were collected from 2006 to 2008 and examined in Parasitology department of Pasteur Institute of Iran.Results: Generally, adult worms, larvae, and eggs of 13 species of various parasitic helminths were recovered. Necropsy examinations showed that 96.47% animals harbored at least one helminth species. The prevalence of different species in necropsy were Mesocestoides sp. 84.7%, Rictolaria spp. 55.3%, Macranthorhynchus hirudinaceus 45.9%, Toxocara canis 43.5%, Toxascaris spp. 35.3%, Joyeuxiella sp. 34.1%; hookworms; 22.4%, Taenia spp. 11.8%, Alaria spp. 2.4% and Dipylidium caninum 1.2%. Besides, eggs belonging to 10 species of parasitic helminths were identified in 46 fecal samples and generally, 30.9% of samples harbored eggs of at least one helminth species.Conclusion: The high prevalence of various helminth infections among canids in Moghan plain and contamination of environment by helminths eggs may increase the risk of infection for native people
Fluctuations for the Ginzburg-Landau Interface Model on a Bounded Domain
We study the massless field on , where is a bounded domain with smooth boundary, with Hamiltonian
\CH(h) = \sum_{x \sim y} \CV(h(x) - h(y)). The interaction \CV is assumed
to be symmetric and uniformly convex. This is a general model for a
-dimensional effective interface where represents the height. We
take our boundary conditions to be a continuous perturbation of a macroscopic
tilt: for , , and
continuous. We prove that the fluctuations of linear
functionals of about the tilt converge in the limit to a Gaussian free
field on , the standard Gaussian with respect to the weighted Dirichlet
inner product for some explicit . In a subsequent article,
we will employ the tools developed here to resolve a conjecture of Sheffield
that the zero contour lines of are asymptotically described by , a
conformally invariant random curve.Comment: 58 page
Dark energy constraints from quasar observations
Recent measurements of the parameters of the Concordance Cosmology Model
(CDM) done in the low-redshift Universe with Supernovae Ia/Cepheids,
and in the distant Universe done with Cosmic Microwave Background (CMB) imply
different values for the Hubble constant (67.4 0.5 km s Mpc
from Planck vs 74.03 1.42 km s Mpc, Riess et al. 2019).
This Hubble constant tension implies that either the systematic errors are
underestimated, or the CDM does not represent well the observed
expansion of the Universe. Since quasars - active galactic nuclei - can be
observed in the nearby Universe up to redshift z 7.5, they are suitable
to estimate the cosmological properties in a large redshift range. Our group
develops two methods based on the observations of quasars in the late Universe
up to redshift z4.5, with the objective to determine the expansion rate
of the Universe. These methods do not yet provide an independent measurement of
the Hubble constant since they do not have firm absolute calibration but they
allow to test the CDM model, and so far no departures from this model
were found.Comment: 6 pages, 2 figures, contribution to the Proceedings of the 100 years
of the Polish Physical Society Congress, 16-18 October 2020, Warsaw, Poland.
http://info.ifpan.edu.pl/APP
Multiwavelength study of extreme variability in LEDA 1154204: A changing-look event in a type 1.9 Seyfert
Context. Multiwavelength studies of transients in actively accreting
supermassive black holes have revealed that large-amplitude variability is
frequently linked to significant changes in the optical spectra -- a phenomenon
referred to as changing-look AGN (CLAGN).
Aim. In 2020, the Zwicky Transient Facility detected a transient flaring
event in the type-1.9 AGN 6dFGS~gJ042838.8-000040, wherein a sharp increase in
magnitude of 0.55 and 0.3 in the - and -bands, respectively,
occurred over 40 days. Spectrum Roentgen Gamma (SRG)/eROSITA also
observed the object in X-rays as part of its all-sky survey, but only after the
flare had started decaying.
Methods. We performed a three-year, multiwavelength follow-up campaign of the
source to track its spectral and temporal characteristics. This campaign
included multiple ground-based facilities for optical spectroscopic monitoring
and space-based observatories including \textit{XMM-Newton} and \textit{Swift}
for X-ray and UV observations.
Results. An optical spectrum taken immediately after the peak revealed a
changing-look event wherein the source had transitioned from type 1.9 to 1,
with the appearance of a double-peaked broad H line and a blue
continuum, both absent in an archival spectrum from 2005. The X-ray emission
exhibits dramatic flux variation: a factor of 17, but with no spectral
evolution, as the power-law photon index remained 1.9. There is no
evidence of a soft X-ray excess. Overall the object exhibits no apparent
signatures of a tidal disruption event.
Conclusions. The transient event was likely triggered by a disk instability
in a pre-existing accretion flow, culminating in the observed multi-wavelength
variability and CLAGN event.Comment: 34 pages, 24 figures, Submitted to Astronomy & Astrophysic
Wavelength-resolved Reverberation Mapping of quasar CTSC30.10: Dissecting MgII and FeII emission regions
We present the results of the reverberation monitoring aimed at MgII broad
line and FeII pseudocontinuum for the luminous quasar CTS C30.10 (z = 0.90052)
with the Southern African Large Telescope covering the years 2012-2021. We
aimed at disentangling the MgII and UV FeII variability and the first
measurement of UV FeII time delay for a distant quasar. We used several methods
for time-delay measurements and determined both FeII and MgII time delays as
well as performed a wavelength-resolved time delay study for a combination of
MgII and FeII in the 2700 - 2900 \AA restframe wavelength range. We obtain the
time delay for MgII of days in the rest frame, while
for FeII we have two possible solutions of days and
in the rest frame. Combining this result with the old
measurement of FeII UV time delay for NGC 5548 we discuss for the first time
the radius-luminosity relation for UV FeII with the slope consistent with
within uncertainties. Since FeII time delay has a shorter time-delay component
but lines are narrower than MgII, we propose that the line delay measurement is
biased towards the BLR part facing the observer, with the bulk of the Fe II
emission may arise from the more distant BLR region, one that is shielded from
the observer.Comment: 22 pages, 19 Figures, 6 Tables, Submitted to Astronomy and
Astrophysics, Comments are welcom
Wavelength-resolved reverberation mapping of intermediate redshift quasars HE 0413-4031 and HE 0435-4312: Dissecting Mg II, optical Fe II, and UV Fe II emission regions
We present the wavelength-resolved reverberation mapping (RM) of combined
MgII and UV FeII broad-line emissions for two intermediate redshifts
(z1), luminous quasars - HE 0413-4031 and HE 0435-4312, monitored by the
SALT and 1-m class telescopes between 2012-2022. Through this technique, we aim
to disentangle the Mg II and FeII emission regions and to build a
radius-luminosity relation for UV FeII emission, which has so far remained
unconstrained. Several methodologies have been applied to constrain the time
delays for total MgII and FeII emissions. In addition, this technique is
performed to quantify the inflow or outflow of broad-line region gas around the
supermassive black hole and to disentangle the emission/emitting regions from
lines produced in proximity to each other. The mean total FeII time delay is
nearly equal to the mean total Mg II time delay for HE 0435-4312 suggesting a
co-spatiality of their emissions. However, in HE 0413-4031, the mean FeII time
delay is found to be longer than the mean MgII time delay, suggesting that FeII
is produced at longer distances from the black hole. The UV Fe II R-L relation
is updated with these two quasars and compared with the optical FeII relation,
which suggests that the optical FeII region is located further than the UV FeII
by a factor of 1.7-1.9 i.e. . We
detected a weak pattern in the time delay vs. wavelength relation, suggesting
that the MgII broad-line originates a bit closer to the SMBH than the UV FeII,
however, the difference is not very significant. Comparison of MgII, UV, and
optical FeII R-L relations suggests that the difference may be larger for
lower-luminosity sources, possibly with the MgII emission originating further
from the SMBH. In the future, more RM data will be acquired to put better
constraints on these trends, in particular the UV FeII R-L relation.Comment: 24 pages, 16 figures, 5 tables, Accepted for publication in A&A, in
Pres
Thermally Responsive Amphiphilic Conetworks and Gels Based on Poly(N‑isopropylacrylamide) and Polyisobutylene
Novel amphiphilic conetworks (APCN) consisting of thermoresponsive poly(N-isoproplyacrylamide) (PNiPAAm) cross-linked by hydrophobic methacrylate-telechelic polyisobutylene (MA-PIB-MA) were successfully synthesized in a broad composition range. The resulting PNiPAAm-l-PIB conetworks (“l” stands for “linked by”) were obtained by radical copolymerization of NiPAAm with MA-PIB-MA in tetrahydrofuran, a cosolvent for all the components. Low amounts of extractables substantiated efficient network formation. The composition dependent two glass transition temperatures (Tg) by DSC analysis indicate microphase separation of the cross-linked components without mixed phases. It was found that the PNiPAAm-l-PIB conetworks are uniformly swellable in both water and n-hexane; i.e., these new materials behave either as hydrogels or as hydrophobic gels in aqueous or nonpolar media, respectively. The uniform swelling in both polar and nonpolar solutes indicates cocontinuous (bicontinuous) phase morphology. The equilibrium swelling degrees (R) depend on composition, that is, the higher the PIB content, the lower the R in water and the higher in n-hexane. The PNiPAAm phase keeps its thermoresponsive behavior in the conetworks as shown by significant decrease of the swelling degree in water between 20 and 35 °C. The lower critical solubility temperature (LCST) values determined by DSC are found to decrease from 34.1 °C (for the pure PNiPAAm homopolymer) to the range of 25–28 °C in the conetworks, and the extent of the LCST decrease is proportional with the PIB content. Deswelling-swelling, i.e., heating–cooling, cycle indicates insignificant hysteresis in these new thermoresponsive materials. This indicates that PNiPAAm-l-PIB conetworks with predetermined and thermoresponsive swelling behavior can be designed and utilized in several advanced applications on the basis of results obtained in the course of this study
Biodegradable magnesium matrix composites for bone fixation devices
When a bone is fractured, it loses its structural integrity which makes it unable to bear any mechanical load. Therefore, a broken bone must be supported until it regains its strength to handle the body's movement and weight. A surgical procedure is needed to set a fractured bone. This procedure often involves repositioning the bone fragments into their natural position and then, attaching them together using internal fixation devices such as plates and screws. These fixation devices restore load-beanng capacity to bone, allowing the fractured bone to be healed by the primary bone healing mechanism. To date, implants used for internal fixadon are usually made from titanium and stainless steel, which are strong but, notorious for triggering adverse reactions such allergic responses caused by implant erosion in patients. Therefore, permanent fixtures should be removed from the body after the fractured bone heals sufficiently, which imposes another invasive surgery on the patient. The advent of biodegradable magnesium-based composites about two decades ago was an attempt to address the clinical complications regarding the permanent fixtures. However, magnesium-based composites are still in their infancy, and a have a lot to achieve before being considered as fully functional materials for bone fixation purposes. Currently, there are two major issues with magnesium composites. Firstly, most of the magnesium-based composites made to date lack sufficient mechanical integrity, making them unsuitable for load-bearing applications. The second, and the most important, issue would be the rapid degradation of magnesium when exposed to physiological solutions, causing pre-mature mechanical failure before the patient fully recovers. The main aim of this thesis is to provide the necessary background and technical information to address these issues, and to be a reliable platform for future researches on the subject to build upon.Biomaterials & Tissue Biomechanic
Healthcare professionals-related factors affecting parents' participation in decision making for neonates with life-threatening conditions: A qualitative study
Rationale, aims, and objectives: Neonates with life-threatening conditions face complex clinical circumstances that confront parents and professionals with ethical decisions. Parents' participation in decision making has not gained sufficient attention in practice. Understanding factors affecting parents' participation is required. This study is part of a comprehensive project that explored the process of parents' participation in decision making for neonates with life-threatening conditions. The current study aimed to explore healthcare professionals-related factors affecting parents' participation in decision-making for neonates with life-threatening conditions. Methods: A grounded theory methodology was used in the comprehensive project. Twenty-two interviews/68 hours of observation were conducted. Data were concurrently analysed throughout data generation and constant comparative analysis. Data collected until theoretical saturation was reached, the extracted categories were coherent and the emerging theory made sense. After coding stages, the core category and the relationships with other main categories involved in the process of parents' participation in decision-making were developed. For this study, the category reflecting healthcare professionals-related factors affecting parents' participation in decision-making was reported. Results: Four themes were found: risk aversion including fear of litigation, fear of being accountable to the parents, and fear of bearing emotional distress; unprofessionalism including poor adherence to professional ethics, inadequate skill/knowledge, poor communication, and nurses' negligence in playing their professional role; information deficiencies including insufficient information, conflicting information, and complex and technical information, and clashes of attitudes including conflict about parents' participation in decision-making and conflict about the best interest of neonates. Conclusion: Professionals should be aware of their role in involving parents in decision making. Training professionals on family centred care principle and communication skills contribute to support parents emotionally and respond empathically to their negative expressions. Training on ethics, development, and dissemination of guidelines and rules of conduct can make professionals more sensitive to ethical aspects of their work and may reduce their fear of litigation. © 2020 John Wiley & Sons Lt
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