228 research outputs found

    Approximately orthogonality preserving mappings on Hilbert C_{0}(Z)-modules

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    In this paper, we will use the categorical approach to Hilbert (C^{ast})-modules over a commutative (C^{ast})-algebra to investigate the approximately orthogonality preserving mappings on Hilbert (C^{ast})-modules over a commutative (C^{ast})-algebra. Indeed, we show that if (Psi:Gamma rightarrow Gamma^{prime} ) is a nonzero ( C_{0}(Z) )-linear (( delta , varepsilon))-orthogonality preserving mapping between the continuous fields of Hilbert spaces on a locally compact Hausdorff space (Z), then (Psi) is injective, continuous and also for every ( x, y in Gamma ) and (z in Z), [ vert langle Psi(x),Psi(y) rangle(z) - varphi^2(z) langle x,y rangle(z) vert leq frac{4(varepsilon - delta)}{(1-delta)(1+varepsilon)} Vert Psi(x) Vert Vert Psi(y) Vert, ] where (varphi(z) = sup { Vert Psi(u)(z) Vert : u ~ text{is a unit vector in} ~ Gamma })

    The Role of Sulfated Materials for Biodiesel Production from Cheap Raw Materials

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    There is an urgent need to reduce global greenhouse gas emissions, yet to date the decarbonization of the transportation industry has been slow and of particular difficulty. While fossil fuel replacements such as biodiesel may aid the transition to a less polluting society, production at the industrial scales required is currently heavily dependent on chemical catalysis. Conventional two-step homogenous routes require the challenging separation of catalyst from the obtained product; however, heterogenous solid catalysts bring new considerations such as material stability, surface area, porosity, deactivation effects, and reduced reactivities under mild conditions. Nanomaterials present an attractive solution, offering the high reactivity of homogenous catalysts without complex recyclability issues. Slightly less reactive, acidic sulfated nanomaterials may also demonstrate greater stability to feedstock impurity, extending lifetime and improved versatility to a range of starting feeds. There remains, however, much work to be done in demonstrating the full-scale feasibility of such catalysts. This review explores recent developments over time in acidic sulfated nanocatalysis for biodiesel production, with particular focus on metal oxides, magnetic nanoparticles, silica-supported nanomaterials, and acidic carbon nanocatalysts. Included are various summaries of current progress in the literature, as well as recommendations for future research

    The devices, experimental scaffolds, and biomaterials ontology (DEB): a tool for mapping, annotation, and analysis of biomaterials' data

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    The size and complexity of the biomaterials literature makes systematic data analysis an excruciating manual task. A practical solution is creating databases and information resources. Implant design and biomaterials research can greatly benefit from an open database for systematic data retrieval. Ontologies are pivotal to knowledge base creation, serving to represent and organize domain knowledge. To name but two examples, GO, the gene ontology, and CheBI, Chemical Entities of Biological Interest ontology and their associated databases are central resources to their respective research communities. The creation of the devices, experimental scaffolds, and biomaterials ontology (DEB), an open resource for organizing information about biomaterials, their design, manufacture, and biological testing, is described. It is developed using text analysis for identifying ontology terms from a biomaterials gold standard corpus, systematically curated to represent the domain's lexicon. Topics covered are validated by members of the biomaterials research community. The ontology may be used for searching terms, performing annotations for machine learning applications, standardized meta-data indexing, and other cross-disciplinary data exploitation. The input of the biomaterials community to this effort to create data-driven open-access research tools is encouraged and welcomed.Preprin

    The most common laboratory procedures for the evaluation of EPB TBMs excavated material ecotoxicity in Italy: A review

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    The rapid development of the mechanized tunneling in current decades has raised serious concerns about the environmental impact of large quantities of the muck. EPB-TBMs require the use of foaming agents for optimizing the soil conditioning.These agents could contain some chemicals (e.g., sodium lauryl ether sulfate – SLES) that are not included in the current legislation at the Italian or EU level. In order to minimize the project costs, it is useful to re-use the excavated soil as a reusable by-product that requires that it does not have any environmental impact on the ecosystems. For this purpose, to draw up a site-specific protocol is a practical and successful tool to evaluate the environmental compatibility of excavated soil during the tunneling. It can rely on one-month experiments at a microcosm or mesocosm scale using soil coming from the excavated site.At fixed times (from 0 to 28 days) the chemical degradation of the chemical together with ecotoxicological tests can be performed on soil or soil-water extracts. Both aquatic and terrestrial organisms are used and the choice of the tests depends on the final destination site.The results of the residual concentration of SLES in soil and in the elutriates, together with those of the ecotoxicological tests, make it possible to evaluate the temporary storage of spoil material and the time necessary for obtaining a safe soil debris to be used as a by-product.These data are usually included in the site-specific protocol to be applied during the excavation phase.This paper describes the main methodological aspects regarding microcosm experiments

    Treatment Failure in Cutaneous Leishmaniasis Patients Referred to the School of Public Health, Tehran University of Medical Sciences During 2008-2017

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    Background: Cutaneous leishmaniasis (CL) is a vector borne disease predominantly found in tropical and subtropical countries, including Iran. For more than 6 decades, pentavalent antimonials have been used successfully worldwide for the treatment of leishmaniasis, but over the past few years, clinical resistance to these medications has increased. In this study, we evaluated CL patients who did not show any desirable responses to the anti-leishmanial treatment within a 10-year period (2008 to 2017). Methods: All patients from different parts of Iran suspected of having cutaneous leishmaniasis, who were referred to the laboratory of leishmaniosis in Tehran University of Medical Sciences from 2008-2017 were parasitological examined. Results: During this period, a total of 1480 suspected CL patients were referred to the laboratory of leishmaniosis. Samples from 655 patients (70.8) suspected of having CL were positive microscopically. The failure rate in patients treated with anti-leishmaniasis medications for a minimum of three complete treatment periods was 1.83 (12 cases). There was no association between the number and size of skin lesions and patient characteristics. Also, the route of drug administration had no significant effect on the number and size of lesions. Conclusion: In the present study, treatment failure was found in some confirmed CL patients treated with meglumine antimoniate. Over the past few years, it seems that had been increased in resistance to these medications. So, a review of the correct implementation of the treatment protocol and/or a combination therapy may be helpful in preventing an increase in the rate of treatment failure

    Prefrontal cortex supports speech perception in listeners with cochlear implants

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    Cochlear implants are neuroprosthetic devices that can restore hearing in people with severe to profound hearing loss by electrically stimulating the auditory nerve. Because of physical limitations on the precision of this stimulation, the acoustic information delivered by a cochlear implant does not convey the same level of acoustic detail as that conveyed by normal hearing. As a result, speech understanding in listeners with cochlear implants is typically poorer and more effortful than in listeners with normal hearing. The brain networks supporting speech understanding in listeners with cochlear implants are not well understood, partly due to difficulties obtaining functional neuroimaging data in this population. In the current study, we assessed the brain regions supporting spoken word understanding in adult listeners with right unilateral cochlear implants (n=20) and matched controls (n=18) using high-density diffuse optical tomography (HD-DOT), a quiet and non-invasive imaging modality with spatial resolution comparable to that of functional MRI. We found that while listening to spoken words in quiet, listeners with cochlear implants showed greater activity in the left prefrontal cortex than listeners with normal hearing, specifically in a region engaged in a separate spatial working memory task. These results suggest that listeners with cochlear implants require greater cognitive processing during speech understanding than listeners with normal hearing, supported by compensatory recruitment of the left prefrontal cortex

    Comparative biological parameters of the cotton bollworm, Helicoverpa armigera (Lep.: Noctuidae) on various corn hybrids

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    برخی پارامترهای زیستی کرم غوزه پنبه، Helicoverpa armigera (Hübner) روی هیبریدهای مختلف ذرت (SC700، SC704، SC500، DC370 و SC260) در قالب رژیم غذای مصنوعی تحت شرایط آزمایشگاهی (دمای 1 ± 25 درجه سلسیوس، رطوبت نسبی 5 ± 65 درصد و دوره نوری 16 ساعت روشنایی و 8 ساعت تاریکی) بررسی شد. لاروهای پرورش‌یافته روی هیبرید SC700 طولانی‌ترین دوره رشدی قبل از بلوغ (21/41 روز)، کم‌ترین باروری روزانه (90/100 روز) و کم‌ترین شاخص زیستی (69/0 گرم در روز) را نشان دادند. براساس نتایج به‌دست آمده، هیبرید SC700 میزبان نامناسبی برای رشد و نموکرم غوزه پنبه بود

    The Long-term Visual Outcomes of Primary Congenital Glaucoma

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    Purpose: To evaluate the long-term visual outcomes of ab externo trabeculotomy for primary congenital glaucoma (PCG) at a single pediatric ophthalmology center. Methods: In this retrospective single-center case series, data from 63 eyes of 40 patients who underwent ab externo trabeculotomy between September 2006 and June 2018 were included. The data were analyzed for best corrected visual acuity (BCVA), stereopsis, and surgical success. Kaplan–Meier analysis was performed using the surgical success criteria defined as intraocular pressure (IOP) ≤ 21 mmHg and ≥ 20% below baseline without the need for additional glaucoma surgery. Results: BCVA at the time of diagnosis was 0.37 ± 0.48 logMAR, which changed to 0.51 ± 0.56 logMAR at the final follow-up (P = 0.08). Twenty-five percent of patients had BCVA equal to or better than 20/40 at the final visit. The mean refraction at baseline was –4.78 ± 5.87 diopters, which changed to less myopic refraction of –2.90 ± 3.83 diopters at the final visit. Optical correction was prescribed in 66% of eyes at the final visit. The average final stereopsis was 395.33 sec of arc. The linear regression model showed a significant association between the surgery success rate and final BCVA as well as stereoacuity (Pvalues: 0.04 and 0.03, respectively). Intraocular pressure (IOP) decreased significantly from 29.79 ± 7.67 mmHg at baseline to 16.13 ± 3.41 mmHg at the final follow-up (P = 0.001). Conclusion: Patients with PCG can achieve an acceptable visual acuity and stereoacuity, particularly in cases of timely intervention and close follow-up

    Elastic Chiral Waveguides with Gyro-Hinges

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    This article presents a novel chiral structure, consisting of Euler–Bernoulli beams connected to gyroscopic spinners.Anew type of boundary condition is introduced, which is referred to as a gyrohinge. In this system, flexural waves are coupled with rotational motion.Time-harmonic conditions are derived by assuming small nutation angles of the spinners. It is shown that the eigenfrequencies of a finite beam with gyro-hinges at one or both ends change dramatically with the moments of inertia and the spin and precession rates of the spinners. The formulation is then extended to elastic beams with periodically-spaced gyro-hinges, whose dispersion properties are investigated in detail. In particular, it is shown how stop-bands and standing modes are affected by the introduction of gyroscopic spinners at the junctions. It is also demonstrated that a periodic system composed of beams connected by gyro-hinges represents a good approximation of a gyrobeam, a theoretical structural element consisting of an elastic beam possessing a continuous distribution of stored angular momentum. The gyricity coefficient of a gyrobeam is then interpreted in terms of the physical parameters of the system of beams with gyroscopic spinners. This article opens a new perspective on the design and practical implementation of chiral mechanical systems
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