198 research outputs found
Transmittance and reflectance measurements at terahertz frequencies on a superconducting BaFe_{1.84}Co_{0.16}As_2 ultrathin film: an analysis of the optical gaps in the Co-doped BaFe_2As_2 pnictide
Here we report an optical investigation in the terahertz region of a 40 nm
ultrathin BaFeCoAs superconducting film with
superconducting transition temperature T = 17.5 K. A detailed analysis of
the combined reflectance and transmittance measurements showed that the optical
properties of the superconducting system can be described in terms of a
two-band, two-gap model. The zero temperature value of the large gap
, which seems to follow a BCS-like behavior, results to be
(0) = 17 cm. For the small gap, for which (0) = 8
cm, the temperature dependence cannot be clearly established. These gap
values and those reported in the literature for the BaFeCoAs
system by using infrared spectroscopy, when put together as a function of
T, show a tendency to cluster along two main curves, providing a unified
perspective of the measured optical gaps. Below a temperature around 20 K, the
gap-sizes as a function of T seem to have a BCS-like linear behavior, but
with different slopes. Above this temperature, both gaps show different
supra-linear behaviors
'A hard-won capability': the experiences of parents managing their babies' medicines after discharge from a neonatal unit.:'A hard-won capability'
IntroductionParents of babies who required neonatal care are responsible for managing their medicines after they are discharged home. There is wide variation in the information and amount of preparation given to parents prior to assuming this challenging task. The aim of the Parent co-Designed Drug Information for parents and Guardians Taking Neonates home (PADDINGToN) study was to explore parents' experiences of managing their babies' medicines post discharge from a neonatal unit and to use this information to develop suitable resources for future families.MethodsA qualitative participatory interpretative approach using a mixture of remote and face-to-face small group interviews or one-to-one interviews was used. Parents were recruited using social media advertisements and convenience sampling from five study sites (four neonatal units in England and one in Ireland). Parents from other neonatal units were invited to take part through social media advertisement. The interviews were audio-recorded and inductive reflexive thematic analysis was used to analyze the data.Results17 parents (14 mothers, 3 fathers) participated. One over-arching theme, 'A hard won capability', and four major interpretive themes were generated from the analysis of the data: Being in NICU and the prospect of going home: emotional and practical challenges; Living the reality of being at home: the uncertainty associated with giving medicines; Being at home: battling the system and a lack of support/knowledge; and Suggesting ways forward: parents' lived insights into improving information and resources.ConclusionDespite the challenges they faced, parents developed strategies for safely and reliably managing medicines administration and they assimilated knowledge, built their confidence and achieved a capability in medicines administration. Their experiences have been used to build a suite of medicines administration resources to support future parents.</jats:sec
Efficacy of a “Rescue” Ciprofloxacin-Based Regimen for Eradication of Helicobacter pylori Infection after Treatment Failures
The aim of our study was to evaluate the efficacy and tolerability of a ciprofloxacin-based regimen for H. pylori eradication failures as an alternative to bismuth based quadruple therapy. Methods. Design: prospective single-center study. Patients in whom a first eradication trial with omeprazole/esomeprazole, clarithromycin plus amoxicillin or tinidazole/metronidazole had failed were included. H. pylori status: established by histology, rapide urease test and polymerase chain reaction. Intervention: esomeprazole 20 mg, ciprofloxacin 500 mg, and metronidazole 500 mg, administered together before breakfast and dinner for 10 days. Susceptibility testing was performed by the Epsilometer test. Ciprofloxacin resistance was defined as a MIC of ≥1 μg/mL. Eradication was established by a negative 13C-UBT and 4–6 weeks post-therapy. Efficacy and side effects were determined. Results. 34 patients were enrolled, 32 completed the study. Compliance was excellent (100%). Side effects were mild. Ciprofloxacin-based therapy cured 65% (22/34) of patients by intention to treat and 69% (22/32) per protocol analysis. The prevalence of ciprofloxacin resistance was 8%. Conclusions. The effectiveness of ciprofloxacin-based therapy was greatly reduced despite the high prevalence of ciprofloxacin sensitive H. pylori strains. Bismuth based quadruple therapy still remain the best choice as a “rescue” regimen in our region
Decoding Corticotropin-Releasing Factor Receptor Type 1 Crystal Structures.
The structural analysis of class B G protein-coupled receptors (GPCR), cell surface proteins responding to peptide hormones, has until recently been restricted to the extracellular domain (ECD). Corticotropin-releasing factor receptor type 1 (CRF1R) is a class B receptor mediating stress response and also considered a drug target for depression and anxiety. Here we report the crystal structure of the transmembrane domain of human CRF1R in complex with the small-molecule antagonist CP-376395 in a hexagonal setting with translational non-crystallographic symmetry. Molecular dynamics and metadynamics simulations on this novel structure and the existing TMD structure for CRF1R provides insight as to how the small molecule ligand gains access to the induced-fit allosteric binding site with implications for the observed selectivity against CRF2R. Furthermore, molecular dynamics simulations performed using a full-length receptor model point to key interactions between the ECD and extracellular loop 3 of the TMD providing insight into the full inactive state of multidomain class B GPCRs.This is the accepted manuscript. It is currently embargoed pending publication
Rotational and high-resolution infrared spectrum of HCN: global ro-vibrational analysis and improved line catalogue for astrophysical observations
HCN is an ubiquitous molecule in interstellar environments, from external
galaxies, to Galactic interstellar clouds, star forming regions, and planetary
atmospheres. Observations of its rotational and vibrational transitions provide
important information on the physical and chemical structure of the above
environments. We present the most complete global analysis of the spectroscopic
data of HCN. We have recorded the high-resolution infrared spectrum from
450 to 1350 cm, a region dominated by the intense and
fundamental bands, located at 660 and 500 cm, respectively, and their
associated hot bands. Pure rotational transitions in the ground and
vibrationally excited states have been recorded in the millimetre and
sub-millimetre regions in order to extend the frequency range so far considered
in previous investigations. All the transitions from the literature and from
this work involving energy levels lower than 1000 cm have been fitted
together to an effective Hamiltonian. Because of the presence of various
anharmonic resonances, the Hamiltonian includes a number of interaction
constants, in addition to the conventional rotational and vibrational l-type
resonance terms. The data set contains about 3400 ro-vibrational lines of 13
bands and some 1500 pure rotational lines belonging to 12 vibrational states.
More than 120 spectroscopic constants have been determined directly from the
fit, without any assumption deduced from theoretical calculations or
comparisons with similar molecules. An extensive list of highly accurate rest
frequencies has been produced to assist astronomical searches and data
interpretation. These improved data, have enabled a refined analysis of the
ALMA observations towards Sgr B2(N2).Comment: 35 pages, 14 figures, accepted for pubblication in ApJ Supplemen
PRELIMINARY STUDIES ON BIOPRECIPITATION PROCESSES MEDIATED BY SULFATE REDUCING BACTERIA (SRB) AND METAL IMMOBILIZATION IN MINE IMPACTED ENVIRONMENTS.
Mining activity often leaves a critical legacy represented by huge volumes of mine wastes and residues, usually made
up of highly reactive materials, which lead to the mobilization and dispersion of harmful elements in soils and waters.
Although these extreme environments are adverse to the development of living organisms, it has been observed that
some microorganisms are able to adapt, playing a role in metal mobility, and becoming part of the resilience of the
system itself.
The Iglesiente and Arburese (SW Sardinia, Italy) mine districts, now abandoned, have been exploited for centuries
by mining activities aimed at Pb-Zn extraction from sulfides and non-sulfides (calamine) deposits. Here,
biogeochemical barriers naturally occur as an adaptation of the ecosystem to environmental stresses. Studies, from
macroscale to microscale, showed that sulfate-reducing bacteria (SRB) may influence metal mobility by mediating
the precipitation of secondary authigenic metal sulfides under reducing conditions. Specifically, framboids of Zn
sulfides and Fe sulfides have been observed in the sections of stream sediments core characterized by the presence
of abundant organic matter, especially residues of vegetal tissues (e.g. roots and stems of Juncus acutus and
Phragmites australis).
Laboratory-scale experiments were performed to better understand the bioprecipitation processes. For this purpose,
anaerobic batch tests were carried out using high polluted mining waters (Zn and sulfate concentrations up to 102
and 103 mg/l, respectively) inoculated with native selected sulfate-reducing bacteria from stream sediments collected
in the investigated areas. Dramatic decrease (up to 100%) in Zn and sulfate was observed in solutions. Moreover,
scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS) analysis, performed on solids recovered
at the end of the experiments, showed the presence of precipitates characterized by a tubular morphology and made
up by S and Zn. SRB inocula were studied by next-generation sequencing (NGS) approach, with the aim to compare
the microbial diversity of the different SRB communities and to search for indigenous novel metal-tolerant
sulfidogenic microorganisms.
These findings represent a valuable step forward to plan effective bioremediation strategies for reducing metal
mobility and dispersion. Also, bioprecipitation mediated by SRB can have great potentialities for metal recovery and
our results can help to develop biomining techniques.
The authors acknowledge CESA (E58C16000080003) from RAS and RAS/FBS (F72F16003080002) grants, and the
CeSAR (Centro Servizi d'Ateneo per la Ricerca) of the University of Cagliari, Italy, for SEM analysis
A Journey from Thermally Tunable Synthesis to Spectroscopy of Phenylmethanimine in Gas Phase and Solution
Phenylmethanimine is an aromatic imine with a twofold relevance in chemistry: organic synthesis and astrochemistry. To tackle both aspects, a multidisciplinary strategy has been exploited and a new, easily accessible synthetic approach to generate stable imine-intermediates in the gas phase and in solution has been introduced. The combination of this formation pathway, based on the thermal decomposition of hydrobenzamide, with a state-of-the-art computational characterization of phenylmethanimine laid the foundation for its first laboratory observation by means of rotational electric resonance spectroscopy. Both E and Z isomers have been accurately characterized, thus providing a reliable basis to guide future astronomical observations. A further characterization has been carried out by nuclear magnetic resonance spectroscopy, showing the feasibility of this synthetic approach in solution. The temperature dependence as well as possible mechanisms of the thermolysis process have been examined
Recommendations for the Management of Hepatitis C Virus Infection Among People Who Inject Drugs
In the developed world, the majority of new and existing hepatitis C virus (HCV) infections occur among people who inject drugs (PWID). The burden of HCV-related liver disease in this group is increasing, but treatment uptake among PWID remains low. Among PWID, there are a number of barriers to care that should be considered and systematically addressed, but these barriers should not exclude PWID from HCV treatment. Furthermore, it has been clearly demonstrated that HCV treatment is safe and effective across a broad range of multidisciplinary healthcare settings. Given the burden of HCV-related disease among PWID, strategies to enhance HCV assessment and treatment in this group are urgently needed. These recommendations demonstrate that treatment among PWID is feasible and provides a framework for HCV assessment, management, and treatment. Further research is needed to evaluate strategies to enhance assessment, adherence, and SVR among PWID, particularly as new treatments for HCV infection become availabl
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