734 research outputs found
Extremely wideband signal shaping using one- and two-dimensional nonuniform nonlinear transmission lines
We propose a class of electrical circuits for extremely wideband (EWB) signal shaping. A one-dimensional, nonlinear, nonuniform transmission line is proposed for narrow pulse generation. A two-dimensional transmission lattice is proposed for EWB signal combining. Model equations for the circuits are derived. Theoretical and numerical solutions of the model equations are presented, showing that the circuits can be used for the desired application. The procedure by which the circuits are designed exemplifies a modern, mathematical design methodology for EWB circuits
The response of tinea capitis to treatment with a two-week oral terbinafine
زمینه و هدف: درماتوفیتوز سر عبارت است از عفونت قارچی پوست سر که در اثر تهاجم درماتوفیتها به ساقه مو ایجاد می شود. از میان درماتوفیتهای پاتوژن فقط انواع میکروسپوروم و ترایکوفایتون باعثآلوده شدن موها می شوند. یکی از داروهای مصرفی برای درمان عفونت های قارچی، تربینافین میباشد که تداخلات واضح با سایر داروها و مصرف غذا ندارد و بسته به حساسیت گونه قارچ و شدت عفونت طول درمان با آن 2 تا 6 هفته پیشنهاد شده است. ولی بهترین دوره درمانی مشخص نشده است. لذا این مطالعه با هدف تعیین پاسخ عفونت های قارچی سر به درمان 2 هفتهای تربینافینخوراکی انجام گرفت. روش بررسی: در یک مطالعه کارآزمایی بالینی روی 29 بیمار با تشخیص بالینی ابتلا به عفونت قارچی سر، آزمایش مستقیم با محلول پتاس 10 و کشت روی محیط سابورو و دکستروز آگار به عمل آمد. سپس این بیماران تحت درمان دو هفتهای با تربینافین خوراکی قرار گرفتند و در سه نوبت (قبل از درمان، بعد از درمان و ده هفته بعد از شروع درمان) تحت معاینه و آزمایشات تشخیصی قرار گرفتند. دادهها با استفاده از آزمون دقیق فیشرتجزیه و تحلیل شدند. یافته ها: ارگانیسمهای مولد عفونت در 9 مورد میکروسپوروم و 20 مورد ترایکوفایتون بودند. بعد از دو هفته درمان و گذشت ده هفته از شروع درمان، در آزمایش مستقیم از نمونه بالینی 29 بیمار مراجعه کننده 7 مورد اکتوتریکس یافت شد و بقیه موارد منفی بودند. نتایج به دست آمده از کشت نمونه ها همه 20 مورد بیمار مبتلا به گونه ترایکوفایتون درمان شدند در حالی که 100 میکروسپوروم ها (9 مورد) به درمان جواب نداده و درمان نشدند. نتیجهگیری: جهت درمان بیماران مبتلا به درماتوفیتوز سر در گونههای ترایکوفایتون میتوان از تربینافین خوراکی به مدت 2 هفته استفاده کرد. ولی این رژیم درمانی برای میکروسپوروم ها مؤثر نیست
Synthesis and characterization of nanocomposite NiFe2O4@SalenSi and its application in efficient removal of Ni(II) from aqueous solution
In this work, nano ferrite spinel NiFe2O4 was synthesized by sol-gel method and characterized by SEM, XRD, FT-IR, and VSM. In second step Schiff base made from salicylaldehyde and amino propyl triethoxy silane was used for modification of the synthesized nano ferrit. In the third step removal of Ni(II) was done using modified adsorbent and 95% efficiency was achieved. The removal rate was determined by atomic absorption spectroscopy. These studies showed that the Freundlich isotherm model was fitted well with adsorption data. Moreover, the pseudo-second order kinetic model was fitted very well with experimental data. The results demonstrated that NiFe2O4@SalenSi nanoadsorbent can be used for the removal and recovery of metal ions from wastewater over a number of cycles, indicating its suitability for the design of a continuous process. KEY WORDS: Nano ferrite, Sol-gel method, Schiff base, Removal of Ni(II), Magnetic nanocomposite Bull. Chem. Soc. Ethiop. 2018, 32(1), 77-88DOI: https://dx.doi.org/10.4314/bcse.v32i1.
Effect of mycorrhiza symbiosis on the Nacl salinity in Sorghum bicolor
In order to determine mycorrhizal symbiosis on the Nacl salinity tolerance in Sorghum bicolor (aspydfyd cultivar), an experiment with two factors was done in Damghan Islamic Azad University laboratory (Iran) in 2007. The first factor with two levels (mycorihizal and non-mycorihizal) and second factor with six levels Nacl concentration of (0, 50, 100, 150, 200 and 250 Mmol) were examined in a random design with three replication in sand environment for 15 weeks. The measurements were the absorption of K, Na, P, N, plant growth, tolerance for different salinity concentrations and traits such as stem and root dry weight and the length of stem. The results showed that the dry weight and stem height in M plants were higher than NM plants. The increase in Nacl concentration decreased the stem height in both groups. However, there was no significant different in root dry weight. The measurement of elements in different organs showed that with increase in Nacl concentration, there would be a significant decrease in N, P, K absorption. But Na absorption increase is more in lower Nacl concentration. Generally, the amount of N, P, K in M plant organs is more than NM plant organs. The result of the experiment showed that mycorrhizal symbiosis is not only effective on element absorption, but also in plant growth and to some extent on salinity tolerance of the plant. So it will be suggested that mycorrhizal be used in salty soils with high Nacl for Sorghum bicolor.Key words: Sorghum, mycorrhizal, salinity, symbiosis, tolerance
A solution of the fractional differential equations in the setting of -metric space
In this paper, we study the existence of solutions for the following differential equations by using a fixed point theorems where , is the Caputo derivative of order , , respectively and is continuous. The results are well demonstrated with the aid of exciting examples
Nonvolatile memory with molecule-engineered tunneling barriers
We report a novel field-sensitive tunneling barrier by embedding C60 in SiO2
for nonvolatile memory applications. C60 is a better choice than ultra-small
nanocrystals due to its monodispersion. Moreover, C60 provides accessible
energy levels to prompt resonant tunneling through SiO2 at high fields.
However, this process is quenched at low fields due to HOMO-LUMO gap and large
charging energy of C60. Furthermore, we demonstrate an improvement of more than
an order of magnitude in retention to program/erase time ratio for a metal
nanocrystal memory. This shows promise of engineering tunnel dielectrics by
integrating molecules in the future hybrid molecular-silicon electronics.Comment: to appear in Applied Physics Letter
Comments on 'Fast and scalable search of whole-slide images via self-supervised deep learning'
Chen et al. [Chen2022] recently published the article 'Fast and scalable
search of whole-slide images via self-supervised deep learning' in Nature
Biomedical Engineering. The authors call their method 'self-supervised image
search for histology', short SISH. We express our concerns that SISH is an
incremental modification of Yottixel, has used MinMax binarization but does not
cite the original works, and is based on a misnomer 'self-supervised image
search'. As well, we point to several other concerns regarding experiments and
comparisons performed by Chen et al
Rapid whole-brain quantitative MT imaging
PURPOSE
To provide a robust whole-brain quantitative magnetization transfer (MT) imaging method that is not limited by long acquisition times.
METHODS
Two variants of a spiral 2D interleaved multi-slice spoiled gradient echo (SPGR) sequence are used for rapid quantitative MT imaging of the brain at 3 T. A dual flip angle, steady-state prepared, double-contrast method is used for combined B and-T mapping in combination with a single-contrast MT-prepared acquisition over a range of different saturation flip angles (50 deg to 850 deg) and offset frequencies (1 kHz and 10 kHz). Five sets (containing minimum 6 to maximum 18 scans) with different MT-weightings were acquired. In addition, main magnetic field inhomogeneities (ΔB) were measured from two Cartesian low-resolution 2D SPGR scans with different echo times. Quantitative MT model parameters were derived from all sets using a two-pool continuous-wave model analysis, yielding the pool-size ratio, F, their exchange rate, k, and their transverse relaxation time, T.
RESULTS
Whole-brain quantitative MT imaging was feasible for all sets with total acquisition times ranging from 7:15 min down to 3:15 min. For accurate modeling, B-correction was essential for all investigated sets, whereas ΔB-correction showed limited bias for the observed maximum off-resonances at 3 T.
CONCLUSION
The combination of rapid B-T mapping and MT-weighted imaging using a 2D multi-slice spiral SPGR research sequence offers excellent prospects for rapid whole-brain quantitative MT imaging in the clinical setting
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