38 research outputs found
In vitro sensitivity pattern of some urinary tract isolates to Carica papaya extracts
Powdered leaves of Carica papaya(L.) were extracted with ethanol and partitioned in chloroform and distilled water. The extract and fractions were tested for antibacterial activity against clinical isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas species using disc diffusion and microbroth dilution technique. The extract and fractions were further subjected to phytochemical tests for the presence of secondary metabolites using standard procedures. Results of sensitivity test results showed that ethanol extract of the leaf was active against E. coli and K. pneumoniae (7mm each) at 1000μg/disc concentration while chloroform and water fractions of the leaf were active against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis at 1000μg/disc concentration with zone diameter of 7mm each. Both the extract and fractions were inactive against P. aeruginosa at all concentrations used in this study. The results of phytochemical screening indicated the presence of alkaloids, flavonoids, steroids and tannins in either ethanol extract, fraction(s) or both. This indicates that the Carica papaya has the potential for the production of drugs against organisms causing urinary tract infections.
Keywords: Sensitivity, Clinical isolates, Urinary tract, Carica papaya, Extract, Fraction
Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2 CoO4
We present a detailed study of the electronic and magnetic interactions of Ba2CoO4, structurally very uncommon because of the isolated CoO4 distorted tetrahedral coordination. We show the presence of Co(d)-O(p) hybridized states characterized by spin polarized oxygen atoms, with their magnetic moments parallel to that on Co. The calculated isotropic exchange interaction parameters, which include the contributions from ligand spins, demonstrate the presence of a three-dimensional (3D) network of magnetic couplings that are partially frustrated in the identified magnetic ground state. Our results indicate that the dominant indirect exchange mechanism responsible for this ground state is mediated by O atoms along the Co-O »O-Co path
Disentangling superconducting and magnetic orders in NaFe_1-xNi_xAs using muon spin rotation
Muon spin rotation and relaxation studies have been performed on a "111"
family of iron-based superconductors NaFe_1-xNi_xAs. Static magnetic order was
characterized by obtaining the temperature and doping dependences of the local
ordered magnetic moment size and the volume fraction of the magnetically
ordered regions. For x = 0 and 0.4 %, a transition to a nearly-homogeneous long
range magnetically ordered state is observed, while for higher x than 0.4 %
magnetic order becomes more disordered and is completely suppressed for x = 1.5
%. The magnetic volume fraction continuously decreases with increasing x. The
combination of magnetic and superconducting volumes implies that a
spatially-overlapping coexistence of magnetism and superconductivity spans a
large region of the T-x phase diagram for NaFe_1-xNi_xAs . A strong reduction
of both the ordered moment size and the volume fraction is observed below the
superconducting T_C for x = 0.6, 1.0, and 1.3 %, in contrast to other iron
pnictides in which one of these two parameters exhibits a reduction below TC,
but not both. The suppression of magnetic order is further enhanced with
increased Ni doping, leading to a reentrant non-magnetic state below T_C for x
= 1.3 %. The reentrant behavior indicates an interplay between
antiferromagnetism and superconductivity involving competition for the same
electrons. These observations are consistent with the sign-changing s-wave
superconducting state, which is expected to appear on the verge of microscopic
coexistence and phase separation with magnetism. We also present a universal
linear relationship between the local ordered moment size and the
antiferromagnetic ordering temperature TN across a variety of iron-based
superconductors. We argue that this linear relationship is consistent with an
itinerant-electron approach, in which Fermi surface nesting drives
antiferromagnetic ordering.Comment: 20 pages, 14 figures, Correspondence should be addressed to Prof.
Yasutomo Uemura: [email protected]
COVID-19 related olfactory dysfunction prevalence and natural history in ambulatory patients
Background: Evidence regarding prevalence of COVID-19 related Olfactory dysfunction (OD) among ambulatory patients is highly variable due to heterogeneity in study population and measurement methods. Relatively few studies have longitudinally investigated OD in ambulatory patients with objective methods.
Methods: We performed a longitudinal study to investigate OD among COVID-19 ambulatory patients compared to symptomatic controls who test negative. Out of 81 patients enrolled, 45 COVID-19 positive patients and an age- and sex-matched symptomatic control group completed the BSIT and a questionnaire about smell, taste and nasal symptoms. These were repeated at 1 month for all COVID-19 positive patients, and again at 3 months for those who exhibited persistent OD. Analysis was performed by mixed-effects linear and logistic regression.
Results: 46.7% of COVID-19 patients compared to 3.8% of symptomatic controls exhibited OD at 1-week post diagnosis (p<0.001). At 1 month, 16.7%, (6 of 36), of COVID-19 patients had persistent OD. Mean improvement in BSIT score in COVID-19 patients between 1-week BSIT and 1 month follow-up was 2.0 (95% CI 1.00 – 3.00, p<0.001). OD did not correlate with nasal congestion (r= −0.25, 95% CI, −0.52 to 0.06, p=0.12). Conclusions: Ambulatory COVID-19 patients exhibited OD significantly more frequently than symptomatic controls. Most patients regained normal olfaction by 1 month. The BSIT is a simple validated and objective test to investigate the prevalence of OD in ambulatory patients. OD did not correlate with nasal congestion which suggests a congestion-independent mechanism of OD
Fungi Associated with the Spoilage of Post-harvest Tomato Fruits Sold in Major Markets in Awka, Nigeria
Abstract Tomato contains large amount of water which makes it more susceptible to spoilage by fungi
Karl Popper and the production of scientific knowledge through the non-recognition of the sacred
Africa is a geographical space where the “impossibilities” are given sacred status. Some occurrences are attributed to one or more sacred or spiritual entities whose intervention or presence can never be questioned. Whoever interrogates such a force is often seen as either abnormal or irresponsible. More often than not, one is bound to ask: Where are the intellectuals whose ideas should be able to remove these biases or veils from the minds of people? But the unfortunate thing is that they too are involved in this despondency. The fundamental problem here is that there is underdevelopment everywhere especially as it relates to science. But Popper had a different idea in mind. His idea is that science flourishes more where nothing is sacred. So, what has Popper done to ensure that sacred entities are overlooked while espousing scientific ideals? Leveraging on the critical method, which is an exercise of careful judgment or evaluation, this work demonstrates that scientific progress is a product of deconstruction of the spiritual aspect of reality. This work will be of benefit for humanity because it will, with instances, show that progress is a product of falsification of the products/processes of the sacred
A review of weldability of carbon steel in arc-based welding processes
The weldability of carbon steel is determined by carbon equivalent (CE) for predicting/estimating preheat temperatures necessary for weld integrity of the weldment. The microstructure of the welded carbon steel at the heat affected zone (HAZ) plays an essential role in the mechanical properties of the weldment, thus, painstakingly selecting welding process and parameters to slowdown the cooling rate are ensued by sound weld quality and crack free weld (enhanced service performance). This research work reviews the effects of various welding processes and parameters on microstructure and mechanical properties of carbon steels in arc-based welding
Design and simulation of air-solar-finned reheating unit: An innovative design of a parabolic trough solar collector
Design and simulation of air-solar-finned reheating unit, an innovative design of a parabolic trough solar collector (PTSC) has been demonstrated in this work. Fundamentally, the design equations were formulated on the optical and thermal principles. The fundamental optical equations were transformed and equated with the original optical equations to realize the optical design functions. The design variables appear in the design function as the unknowns. The design functions were differentiated with respect to the design variables to form design simulatory matrices. Prior to the simulation, the design functions were made to approach zero by the introduction of convergent factors which guarantee the convergence of the simulatory matrices whose final output defines the design variables. The design was algorithmized with a flowchart to justify the design procedures. A slight obtuse-angled rim design was adopted in the design of the reheating unit (RU) which yielded optimum; rim angle of 94°, collector, optical and thermal efficiencies of 0.44, 0.72 and 0.31, respectively, and an optimum exit fluid temperature of C sequel to the simulation of the design equations. Besides, the apparent tradeoffs among the design variables were useful in making design decisions. Considering the pitfalls of the traditional acute-angled rim design (AARD), the present work is advocating for the adoption of slight obtuse-angled rim design (SOARD) technique which will shield the PTSCs from the misalignment issues and equally minimize the thermal losses prone to the acute-angled rim design technique. Also, premium on material selection is recommended for the effective operation of RU
Physical, mechanical and hydration kinetics of particleboards manufactured with woody biomass (Cupressus lusitanica, Gmelina arborea, Tectona grandis), agricultural resources, and Tetra Pak packages
Lignocellulosic wastes resulting from agricultural activities as well as Tetra Pak residues from urban centres can cause significant levels of pollution. A possible action to minimize this problem is to use them in the production of particleboards. The purpose of this study was to evaluate the physical, mechanical, and hydration properties of particleboards manufactured with the mixture of woody biomass (Cupressus lusitanica, Gmelina arborea, and Tectona grandis) and either agricultural wastes [pineapple leaves (Ananas comosus) and palm residues (Elaeis guineensis)] or Tetra Pak residues (TP). The results show that the particleboards prepared with TP and woody biomass can reduce the swelling and water absorption in up to 40% and 50% compared with particleboards without TP. Also, these particleboards had increased flexure resistance and shear stress (up to 100%) compared with those without TP. On the contrary, particleboards prepared with pineapple leaves in combination with woody biomass showed the lowest mechanical properties, particularly for tensile strength, hardness, glue-line shear, and nail and screw evaluation.Los desechos lignocelulósicos resultantes de las actividades agrícolas, así como los residuos de Tetra Pak de los centros urbanos pueden causar niveles significativos de contaminación. Una posible acción para minimizar este problema es usarlos en la producción de tableros de partículas. El propósito de este estudio fue evaluar las propiedades físicas, mecánicas y de hidratación de tableros de partículas fabricados con la mezcla de biomasa leñosa (Cupressus lusitanica, Gmelina arborea y Tectona grandis) y residuos agrícolas [hojas de piña (Ananas comosus) y residuos de palma (Elaeis guineensis)] o residuos de Tetra Pak (TP). Los resultados muestran que los tableros de partículas preparados con TP y biomasa leñosa pueden reducir la hinchazón y la absorción de agua hasta en un 40% y 50% en comparación con los tableros de partículas sin TP. Además, estos tableros de partículas tenían una mayor resistencia a la flexión y al esfuerzo cortante (hasta 100%) en comparación con aquellos sin TP. Por el contrario, los tableros de partículas preparados con hojas de piña en combinación con biomasa leñosa mostraron las propiedades mecánicas más bajas, particularmente para la resistencia a la tracción, la dureza, el corte de la línea de pegamento y la evaluación de clavos y tornillos.Universidad Nacional, Costa RicaEscuela de Químic
Explainable COVID-19 infections identification and delineation using calibrated pseudo labels
The upheaval brought by the arrival of the COVID19 pandemic has continued to bring fresh challenges over the past two years. During this COVID-19 pandemic, there has been a need for rapid identification of infected patients and specific delineation of infection areas in computed tomography (CT) images. Although deep supervised learning methods have been established quickly, the scarcity of both image-level and pixel-level labels as well as the lack of explainable transparency still hinder the applicability of AI. Can we identify infected patients and delineate the infections with extreme minimal supervision? Semi-supervised learning has demonstrated promising performance under limited labelled data and sufficient unlabelled data. Inspired by semisupervised learning, we propose a model-agnostic calibrated pseudo-labelling strategy and apply it under a consistency regularization framework to generate explainable identification and delineation results. We demonstrate the effectiveness of our model with the combination of limited labelled data and sufficient unlabelled data or weakly-labelled data. Extensive experiments have shown that our model can efficiently utilize limited labelled data and provide explainable classification and segmentation results for decision-making in clinical routine. The code is available at https://github.com/ayanglab/XAI COVID-19