986 research outputs found
Global disparities in the treatment of idiopathic inflammatory myopathies: results from an international online survey study
Identifying Risk Factors for Post-COVID-19 Mental Health Disorders: A Machine Learning Perspective
In this study, we leveraged machine learning techniques to identify risk
factors associated with post-COVID-19 mental health disorders. Our analysis,
based on data collected from 669 patients across various provinces in Iraq,
yielded valuable insights. We found that age, gender, and geographical region
of residence were significant demographic factors influencing the likelihood of
developing mental health disorders in post-COVID-19 patients. Additionally,
comorbidities and the severity of COVID-19 illness were important clinical
predictors. Psychosocial factors, such as social support, coping strategies,
and perceived stress levels, also played a substantial role. Our findings
emphasize the complex interplay of multiple factors in the development of
mental health disorders following COVID-19 recovery. Healthcare providers and
policymakers should consider these risk factors when designing targeted
interventions and support systems for individuals at risk. Machine
learning-based approaches can provide a valuable tool for predicting and
preventing adverse mental health outcomes in post-COVID-19 patients. Further
research and prospective studies are needed to validate these findings and
enhance our understanding of the long-term psychological impact of the COVID-19
pandemic. This study contributes to the growing body of knowledge regarding the
mental health consequences of the COVID-19 pandemic and underscores the
importance of a multidisciplinary approach to address the diverse needs of
individuals on the path to recovery. Keywords: COVID-19, mental health, risk
factors, machine learning, Ira
High-Pressure Annealing of a Prestructured Nanocrystalline Precursor to Obtain Tetragonal and Orthorhombic Polymorphs of Hf3N4
Transition metal nitrides containing metal ions in high oxidation states are a significant goal for the discovery of new families of semiconducting materials. Most metal nitride compounds prepared at high temperature and high pressure from the elements have metallic bonding. However amorphous or nanocrystalline compounds can be prepared via metal-organic chemistry routes giving rise to precursors with a high nitrogen:metal ratio. Using X-ray diffraction in parallel with high pressure laser heating in the diamond anvil cell this work highlights the possibility of retaining the composition and structure of a metastable nanocrystalline precursor under high pressure-temperature conditions. Specifically, a nanocrystalline Hf3N4 with a tetragonal defect-fluorite structure can be crystallized under high-P,T conditions. Increasing the pressure and temperature of crystallization leads to the formation of a fully recoverable orthorhombic (defect cottunite-structured) polymorph. This approach identifies a novel class of pathways to the synthesis of new crystalline nitrogen-rich transition metal nitrides
Nanoscale arrays of antimony telluride single crystals by selective chemical vapor deposition
Arrays of individual single nanocrystals of Sb2Te3 have been formed using selective chemical vapor deposition (CVD) from a single source precursor. Crystals are self-assembled reproducibly in confined spaces of 100 nm diameter with pitch down to 500 nm. The distribution of crystallite sizes across the arrays is very narrow (standard deviation of 15%) and is affected by both the hole diameter and the array pitch. The preferred growth of the crystals in the orientation along the diagonal of the square holes strongly indicates that the diffusion of adatoms results in a near thermodynamic equilibrium growth mechanism of the nuclei. A clear relationship between electrical resistivity and selectivity is established across a range of metal selenides and tellurides, showing that conductive materials result in more selective growth and suggesting that electron donation is of critical importance for selective deposition
A Comparison of the Reactivity of the Lattice Nitrogen in Tungsten Substituted Co3Mo3N and Ni2Mo3N
The effect of the partial substitution of Mo with W in Co3Mo3N and Ni2Mo3N on ammonia synthesis activity and lattice nitrogen reactivity has been investigated. This is of interest as the coordination environment of lattice N is changed by this process. When tungsten was introduced into the metal nitrides by substitution of Mo atoms, the catalytic performance was observed to have decreased. As expected, Co3Mo3N was reduced to Co6Mo6N under a 3:1 ratio of H2/Ar. Co3Mo2.6W0.4N was also shown to lose a large percentage of lattice nitrogen under these conditions. The bulk lattice nitrogen in Ni2Mo3N and Ni2Mo2.8W0.2N was unreactive, demonstrating that substitution with tungsten does not have a significant effect on lattice N reactivity. Computational calculations reveal that the vacancy formation energy for Ni2Mo3N is more endothermic than Co3Mo3N. Furthermore, calculations suggest that the inclusion of W does not have a substantial impact on the surface N vacancy formation energy or the N2 adsorption and activation at the vacancy site
Prevalence and causes of failure of receiving thrombolytic therapy in patients with acute ST-segment elevation myocardial infarction
AbstractBackgroundMissing thrombolytic therapy in patients with acute ST-elevation myocardial infarction (STEMI) can have dire consequences. We studied the prevalence and causes of failure of receiving thrombolytic therapy in patients with STEMI and its impact on the clinical outcome during hospitalization.Patients and methodsThis was an observational, analytic, cross sectional study carried out in the CCU and emergency departments of three public hospitals in Port Said, Egypt. We interrogated all patients admitted within 72h of possible acute coronary syndrome and only patients proved to have STEMI as defined by the updated ACC criteria were analyzed for receiving thrombolytic therapy or not. All STEMI patients were subjected to: medical history taking, thorough clinical examination, 12-leads surface electrocardiography, cardiac biomarkers (troponin I), and predischarge trans-thoracic echocardiography.ResultsOf 6522 patients screened, only 288 patients had STEMI. The prevalence of missed thrombolysis in these patients was 45%. Delayed presentation after the onset of symptoms represented the most common cause for failure to receive thrombolysis (54% of the cases), while misdiagnosis at the emergency department represented 35% of the cases. Female gender, diabetes mellitus and inferior location of myocardial infarction were independent predictors of missed thrombolytic therapy. Cardiac death, clinical heart failure and significant cardiac dysrhythmias were higher in patients who missed thrombolysis than in those who received it.ConclusionIn this study, up to 45% of patients with STEMI missed the opportunity to receive thrombolysis, most likely due to delayed presentation or misdiagnosis at the emergency department. Patients with missed thrombolysis were at higher risk of cardiac death, clinical heart failure, and hemodynamically significant cardiac dysrhythmias
Observations of gas flows inside a protoplanetary gap
Gaseous giant planet formation is thought to occur in the first few million
years following stellar birth. Models predict that giant planet formation
carves a deep gap in the dust component (shallower in the gas). Infrared
observations of the disk around the young star HD142527, at ~140pc, found an
inner disk ~10AU in radius, surrounded by a particularly large gap, with a
disrupted outer disk beyond 140AU, indicative of a perturbing planetary-mass
body at ~90 AU. From radio observations, the bulk mass is molecular and lies in
the outer disk, whose continuum emission has a horseshoe morphology. The
vigorous stellar accretion rate would deplete the inner disk in less than a
year, so in order to sustain the observed accretion, matter must flow from the
outer-disk into the cavity and cross the gap. In dynamical models, the putative
protoplanets channel outer-disk material into gap-crossing bridges that feed
stellar accretion through the inner disk. Here we report observations with the
Atacama Large Millimetre Array (ALMA) that reveal diffuse CO gas inside the
gap, with denser HCO+ gas along gap-crossing filaments, and that confirm the
horseshoe morphology of the outer disk. The estimated flow rate of the gas is
in the range 7E-9 to 2E-7 Msun/yr, which is sufficient to maintain accretion
onto the star at the present rate
The reactivity of lattice nitrogen within the Ni2Mo3N and NiCoMo3N phases
In this study, the reactivity of bulk lattice nitrogen within the filled β-Mn structured Ni2Mo3N phase has been investigated by application of powder neutron diffraction and heterolytic nitrogen isotopic exchange measurements. In contrast to Co3Mo3N, despite the similarity in the N immediate local environment comprising NMo6 octahedra, its reactivity is found to be limited and this lower reactivity was maintained upon the introduction of a significant proportion of cobalt to yield its filled β-Mn structured CoNiMo3N quaternary nitride counterpart
Colonisation resistance in the sand fly gut:Leishmania protects Lutzomyia longipalpis from bacterial infection
BACKGROUND: Phlebotomine sand flies transmit the haemoflagellate Leishmania, the causative agent of human leishmaniasis. The Leishmania promastigotes are confined to the gut lumen and are exposed to the gut microbiota within female sand flies. Here we study the colonisation resistance of yeast and bacteria in preventing the establishment of a Leishmania population in sand flies and the ability of Leishmania to provide colonisation resistance towards the insect bacterial pathogen Serratia marcescens that is also pathogenic towards Leishmania. METHODS: We isolated microorganisms from wild-caught and laboratory-reared female Lutzomyia longipalpis, identified as Pseudozyma sp. Asaia sp. and Ochrobactrum intermedium. We fed the females with a sugar meal containing the microorganisms and then subsequently fed them with a bloodmeal containing Leishmania mexicana and recorded the development of the Leishmania population. Further experiments examined the effect of first colonising the sand fly gut with L. mexicana followed by feeding with, Serratia marcescens, an insect bacterial pathogen. The mortality of the flies due to S. marcescens was recorded in the presence and absence of Leishmania. RESULTS: There was a reduction in the number of flies harbouring a Leishmania population that had been pre-fed with Pseudozyma sp. and Asaia sp. or O. intermedium. Experiments in which L. mexicana colonised the sand fly gut prior to being fed an insect bacterial pathogen, Serratia marcescens, showed that the survival of flies with a Leishmania infection was significantly higher compared to flies without Leishmania infection. CONCLUSIONS: The yeast and bacterial colonisation experiments show that the presence of sand fly gut microorganisms reduce the potential for Leishmania to establish within the sand fly vector. Sand flies infected with Leishmania were able to survive an attack by the bacterial pathogen that would have killed the insect and we concluded that Leishmania may benefit its insect host whilst increasing the potential to establish itself in the sand fly vector. We suggest that the increased ability of the sand fly to withstand a bacterial entomopathogen, due to the presence of the Leishmania, may provide an evolutionary pressure for the maintenance of the Leishmania-vector association
Solvothermal water-diethylene glycol synthesis of LiCoPO4 and effects of surface treatments on lithium battery performance
Olivine-structured LiCoPO4 is prepared via a facile solvothermal synthesis, using various ratios of water/
diethylene glycol co-solvent, followed by thermal treatment under Ar, air, 5%H2/N2 or NH3. The
diethylene glycol plays an important role in tailoring the particle size of LiCoPO4. It is found that using
a ratio of water/diethylene glycol of 1 : 6 (v/v), LiCoPO4 is obtained with a homogenous particle size of
�150 nm. The bare LiCoPO4 prepared after heating in Ar exhibits high initial discharge capacity of
147 mA h g1 at 0.1C with capacity retention of 70% after 40 cycles. This is attributed to the enhanced
electronic conductivity of LiCoPO4 due to the presence of Co2P after firing under Ar. The effects of
carbon, TiN and RuO2 coating are also examined. Contrary to other studies, it is found that the
solvothermally synthesised LiCoPO4 samples produced here do not require conductive coatings to
achieve good performance
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