1,316 research outputs found

    Comparison anti-giardia activity of Satureja hortensis alcoholic extract and metronidazole in vitro

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    Background and aims: Giardiasis is known as intestinal infection and created by the flagellate protozoan Giardia lamblia. Some studies showed that phenolic components, present in plant extracts and essential oils, have anti-Giardia activity. The current study was performed to compare anti-Giardia activity of Satureja hortensis (SH) alcoholic extract and metronidazole in vitro. Methods: In this Laboratory-experimental study, it was separated cysts from the feces by Bingham procedure with minor modification. The numbers of cysts were calculated with Hemusytumetr and the purified cysts of Giardia lamblia (500 µl) were exposed with 500 µl of extract at concentrations of 10, 100 and 200 mg/ml and 125 mg/kg of metronidazole for 30, 60 and 120 min. The numbers of dead and live cysts was enumerated with a microscope. Results: Findings in the currnt studyshowed an increase in anti-Giardia activity of extract at high concentrations with increasing time. SH, at 100 mg/ml killed 53 in 30 min, 68 in 60 min and 78 in 120 min. Also, the extract killed by 62 in 30 min, about 88 in 60 minutes and 92 in 120 minutes. The drug had similar effects in 60 and 120 minutes, but it killed 83 in 30 minutes. Conclusion: SH alcoholic extract showed anti-Giardia activity at high rates and more time. Thus, SH extract at 200 mg may be suitable alternative for Metronidazole, without side effects. However, anti-Giardia activity of SH needs to more attentions, especially clinical investigations

    Miniature Optical Atomic Clock: Stabilization of a Kerr Comb Oscillator

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    Mechanical clocks consist of a pendulum and a clockwork that translates the pendulum period to displayed time. The most advanced clocks utilize optical transitions in atoms in place of the pendulum and an optical frequency comb generated by a femtosecond laser as the clockwork. The comb must be stabilized at two points along its frequency spectrum: one with a laser to lock a comb line to a transition in the atom, and another through self referencing to stabilize the frequency interval between the comb lines. This approach requires advanced techniques, so optical atomic clocks are currently laboratory devices in specialized labs. In this paper we leverage unique properties of Kerr comb oscillators for realization of optical atomic clocks in miniature form factors. In particular, we describe a clock based on D1 transition of 87Rb that fits in the palm of the hand, and can be further miniaturized to chip scale.Comment: 4 pages, 4 figure

    Secretion of Food Allergen Proteins in Saliva

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    RATIONALE: Peanut proteins were found to be secreted in 50% of lactating women’s breast milk. We wanted to develop a testing method to predict the secretion of peanut protein in breast milk. The secretion of food protein in saliva was hypothesized to be a possible predictor of secretion of foods in breast milk following ingestion. METHODS: Non-allergic volunteers, some lactating, ingested 50 grams of either whole peanuts, peanut milk or cow’s milk and various immunoassays were utilized to analyze for the presence of peanut or cow’s milk proteins in saliva and breast milk. Saliva and breast milk samples were subjected to SDS-PAGE, Western blot and ELISA analysis with anti-raw and roasted peanut and anti-alpha-casein antibodies and pooled serum IgE from peanut allergic individuals. RESULTS: Peanut protein levels in breast milk were undetectable using Western blot analysis and inconsistent with ELISA analysis. However, peanut proteins around 20 and 30 kDa that reacted with anti-roasted peanut antibody were detected, 6-18 hours following ingestion, in saliva of different individuals. An 18 KDa band that reacts with anti-alpha casein antibody was also detected in saliva 6-18 hours following ingestion. CONCLUSIONS: Secretion of food allergen proteins or peptides in saliva several hours following ingestion may have important implications for delayed allergic reaction by sensitive patients. Also, due to the fact that these proteins or peptides survive digestive enzymes, become absorbed into the blood stream and are subsequently secreted in biological fluids may indicate that they are most likely the sensitizing or tolerizing agent within an allergic food. Funding: National Peanut Board, USD

    Selective reporting: a half signalling load algorithm for distributed sensing

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    Spectrum sensing is a powerful tool of the cognitive cycle to help circumvent the apparent spectrum scarcity faced by wireless transmission systems. To overcome the challenging issues faced by the localized sensing, multiple cognitive radios can cooperate to explore the multiuser diversity and generate a more reliable decision on the presence of a signal in the frequencies of interest. In such a cooperative sensing scenario, a common reporting channel is needed for the transmission of the information of each element. As the number of elements that participate in the sensing operation increases, so does the bandwidth demanded for the reporting channel, quickly becoming the limiting factor in this scenario. To tackle the issue of reducing the sensing report overhead, this paper introduces a new cooperative sensing scheme that introduces silence periods in the reporting and, relying on information theory principles, explores the information present in these periods to reduce by 50% the sensing reporting overhead while maintaining the same performance of standard reporting schemes. Numerical and experimental results confirm the theoretical analysis and show the predicted reduction in reporting overhead and performance preservation

    A Mixture of Regressions Model of COVID-19 Death Rates and Population Comorbidities

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    As the COVID-19 pandemic spread worldwide, it has become clearer that prevalence of certain comorbidities in a given population could make it more vulnerable to serious outcomes of that disease, including fatality. Indeed, it might be insightful from a health policy perspective to identify clusters of populations in terms of the associations between their prevalent comorbidities and the observed COVID-19 specific death rates. In this study, we described a mixture of polynomial time series (MoPTS) model to simultaneously identify (a) three clusters of 86 U.S. cities in terms of their dynamic death rates, and (b) the different associations of those rates with 5 key comorbidities among the populations in the clusters. We also described an EM algorithm for efficient maximum likelihood estimation of the model parameters

    Model for coiling and meandering instability of viscous threads

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    A numerical model is presented to describe both the transient and steady-state dynamics of viscous threads falling onto a plane. The steady-state coiling frequency w is calculated as a function of fall height H. In the case of weak gravity, w ~ H^{-1} and w ~ H are obtained for lower and higher fall heights respectively. When the effect of gravity is significant, the relation w ~ H^2 is observed. These results agree with the scaling laws previously predicted. The critical Reynolds number for coil-uncoil transition is discussed. When the gravity is weak, the transition occurs with hysteresis effects. If the plane moves horizontally at a constant speed, a variety of meandering oscillation modes can be observed experimentally. The present model also can describe this phenomenon. The numerically obtained state diagram for the meandering modes qualitatively agrees with the experiment.Comment: 12 pages, 10 figure

    The angle of repose of spherical grains in granular Hele-Shaw cells: A molecular dynamics study

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    We report the results of three dimensional molecular dynamic simulations on the angle of repose of a sandpile formed by pouring mono-sized cohesionless spherical grains into a granular Hele-Shaw cell. In particular, we are interested to investigate the effects of those variables which may impact significantly on pattern formation of granular mixtures in Hele-Shaw cells. The results indicate that the frictional forces influence remarkably the formation of pile on the grain level. Furthermore, We see that increasing grain insertion rate decreases slightly the angle of repose. We also find that in accordance with experimental results, the cell thickness is another significant factor and the angle of repose decays exponentially by increasing the cell thickness. It is shown that this effect can be interpreted as a cross-over from two to three dimensions. In fact, using grains with different sizes shows that the behaviour of the angle of repose when both size and cell thickness are varied is controlled by a scaled function of the ratio of these two variables.Comment: 8 pages, 12 figures, equation(7) correcte

    Static Analysis of Laminated Piezoelectric Cylindrical Panels

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    Abstract The Static analysis of laminated piezoelectric cylindrical shells with various boundary conditions is presented emp loying Generalized Differential Quadrature (GDQ) method. The first-order shear deformation theory (FSDT) is considered to model the static response of panel. Different symmetric and asymmetric lamination sequences together with various combinations of clamped, simp ly supported and free boundary conditions are considered. Particular interest of this study regards to asymmetric p iezoelectric orthotropic cylindrical panels having free edges and subjected to general electro mechanical loading. Taking into account the effects of shear deformation and initial curvature, a system of fifteen first order partial d ifferential equations (PDEs) in terms of unknown displacements, rotations, mo ments and forces is developed. Several numerical examp les are presented to demonstrate the accuracy and convergence of the proposed method with relatively small nu mber of grid points. It is also revealed that the present method offers similar order of accuracy for all variables including displacements and stress resultants. Further results for panels with particu lar boundary conditions are provided which can be used as benchmarks in future

    Bio-based electrospun fibers for wound healing

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    Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices
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