605 research outputs found
Disordered Carbon nanotube alloys in the Effect Medium Super Cell Approximation
We investigate a disordered single-walled carbon nanotube (SWCNT) in an
effective medium super cell approximation (EMSCA).
First type of disorder that we consider is the presence of vacancies.
Our results show that the vacancies induce some bound states on their
neighbor host sites, leading to the creation of a band around the Fermi energy
in the SWCNT average density of states.Second type of disorder considered is a
substitutional alloy due to it's applications in
hetrojunctions. We found that for a fixed boron (nitrogen) concentration, by
increasing the nitrogen (boron) concentration the averaged semiconducting gap,
, decreases and at a critical concentration it disappears. A consequence
of our results for nano electronic devices is that by changing the
boron(nitrogen) concentration, one can make a semiconductor SWCNT with a
pre-determined energy gap.Comment: 4 page
Petrogenesis of the Lalezar granitoid intrusions (Kerman Province – Iran)
The Lalezar granitoids crop out within volcanic successions of the Urumieh-Dokhtar
Magmatic Assemblage (UDMA). These granitoids have a range from gabbro-diorites to granites in composition. The mineral compositions of the most felsic rocks are characterized by the abundances of Na-plagioclase, quartz, alkali feldspar, biotite and hornblende. In the gabbro-diorite rocks, plagioclase (Ca-rich), hornblende, biotite and clinopyroxene are the most common minerals. Major element geochemical data show that the Lalezar granitoids are mostly metaluminous, although the most felsic members (granites) attain slightly peraluminous compositions and that they have features typical of high-K calc-alkaline rocks. In primitive mantle-normalized trace element spider diagrams, the analysed samples display strong enrichment in LILE compared to HFSE, accompanied by negative anomalies of Nb,Ta and Ti. REE chondrite-normalized plots show moderate LREE enrichment with slight to strong negative Eu anomalies. Rb–Sr geochronological data, mainly dependent on the Sr isotopic composition of biotite, was obtained in two samples and it points to 15-16 Ma. As a
probable, age for the emplacement of the studied intrusives. Initial 87Sr/86Sr ratios and ƐNdi values range from 0.70495 to 0.70565 from +3.1 to +1.5 respectively, which fit into a supra-subduction mantle wedge source for the parental melts and indicates that, in general, crustal contribution for magma diversification was not relevant. Geochemical and isotopic evidence reveal that the Lalezar intrusions are cogenetic I-type granitoids which were generated in a continental arc setting, in agreement with models previously presented in the UDMA
Ferromagnetic semiconductor single wall carbon nanotube
Possibility of a ferromagnetic semiconductor single wall carbon nanotube
(SWCNT), where ferromagnetism is due to coupling between doped magnetic
impurity on a zigzag SWCNT and electrons spin, is investigate. We found, in the
weak impurity-spin couplings, at low impurity concentrations the spin up
electrons density of states remain semiconductor while the spin down electrons
density of states shows a metallic behavior. By increasing impurity
concentrations the semiconducting gap of spin up electrons in the density of
states is closed, hence a semiconductor to metallic phase transition is take
place. In contrast, for the case of strong coupling, spin up electrons density
of states remain semiconductor and spin down electron has metallic behavior.
Also by increasing impurity spin magnitude, the semiconducting gap of spin up
electrons is increased.Comment: 10 pages and 9 figure
Effect of foot reflexology on anxiety and agitation in patients under mechanical ventilation after open heart surgery: A randomized clinical trial study
زمینه و هدف: رویکردهای غیر دارویی از جمله ماساژ بازتابی پا به علت کاهش عوارض و هزینه ها در کانون توجه محققین در جامعه بیماران مختلف قرار گرفته است. این مطالعه با هدف بررسی تأثیر ماساژ بازتابی پا بر اضطراب و بیقراری بیماران تحت تهویه مکانیکی پس از جراحی قلب باز انجام شد. روش بررسی: این مطالعه کارآزمایی بالینی کنترل شده، سه گروهی و دو سو کور با طراحی اندازه گیری مکرر در دو بیمارستان وابسته به دانشگاه علوم پزشکی بقیه الله (عج) تهران، از بهمن1392 تا اردیبهشت 1393 انجام شد. 96 بیمار کاندید جراحی قلب باز به روش نمونه گیری در دسترس انتخاب و به صورت تخصیص تصادفی در سه گروه آزمون (ماساژ بازتابی پا 34 نفر)، درمان نما (تماس سطحی پاشنه پا 30 نفر) و کنترل (مراقبت های معمول 32 نفر) قرار گرفتند. در گروه آزمون، ماساژ بازتابی پا به مدت20 دقیقه بر روی نقاط بازتاب قلب و ریه، انجام شد. میزان اضطراب و بیقراری بر اساس مقیاس سنجش اضطراب (FAS) و مقیاس سنجش بیقراری ریچموند (RSAS) در 6 مرحله زمانی ثبت شد. یافته ها: داده های آماری 92 بیمار (31 نفر گروه آزمون، 30 نفر گروه درمان نما و 31 نفر گروه کنترل) جمع آوری گردید. در مقایسه روند تغییرات سطح اضطراب و بیقراری، آزمون درون گروهی فریدمن نشان داد، بین میانگین سطح اضطراب و بیقراری در گروه ها در مراحل زمانی مختلف تفاوت معنی دار آماری وجود دارد. همچنین آزمون کروسکال والیس نشان داد میزان اضطراب و بیقراری بین سه گروه در مراحل مختلف زمانی تفاوت معنی دار آماری با یکدیگر ندارند. نتیجه گیری: ماساژ بازتابی پا در نقاط بازتابی مربوط به قلب و ریه تغییر معنی داری در کاهش اضطراب و بیقراری بیماران پس از جراحی ایجاد نکرد
The effect of thyroxine on percentage of hatching (Hypophthalmichthys molitrix)
Studies showed that Thyroxine can play an important role on fish growth, osmoregulation system, and other physiological activities. Since the direct effect of thyroxine on growth and metamorphose of bony fish larvae has not been yet approved, therefore, present study were carried out in Shahid Ansary propagation and cultivation farm in order to find out the way of effect of this hormone on the survirval rate and early growth stage of silver carp (Hypophthalmichthys molitrix) fertiled eggs that were bathed in thyroxin with concentrations of 0.1, 0.5 and 1.0 ppm (each one, replicates) for 6 hours. Then they were transfered into large incubators (zoog) with running water. After hatching all larvae were placed in mentioned thyroxin concentration bath for another 6 hours before being transfered into large incubators. Larvae stayed inzoogs until the yolk-sac was absorbed. Finally, live silver carp larvae were counted in separated plates. Results of present study indicated that the ra tio of hatched eggs in 0.5 ppm of thyroxin concentration was higher than other treatment
Geochemistry of granitoids of the Lalezar area (Kerman, Iran)
The Lalezar granitoids crop out within the Urumiyeh-Dokhtar Volcanic Belt (U-DVB) which is the largest volcanic belt in Central Iran. These granitoids intrude Eocene volcano-sedimentary rocks and range from gabbrodiorites to granites, with dominance of diorites and tonalites. The mineral composition of the most felsic rocks is characterized by the abundance of Na-plagioclase, quartz, alkali feldspar and biotite (and hornblende, in granodiorites and tonalites). In dioritic and gabbroic rocks, plagioclase (Ca-rich, in the most mafic lithologies), hornblende, biotite and clinopyroxene are the most common minerals, sometimes accompanied by orthopyroxene. Two kind of enclaves have been identified within the intrusive rocks: some display the same features of the andesitic country volcanic rocks, and therefore, are interpreted as xenoliths; others have mineral assemblages similar to those of the enclosing granitoid but with larger proportions of mafic minerals, which suggests that they can represent disrupted portions of sectors of the magma chamber where preferential settling of heavy minerals took place. Major element geochemical data show that the Lazelar granitoids are mostly metaluminous, although the most felsic members (granites) attain slightly peraluminous compositions, with A/CNK varying from 0.85 to 1.03. Harker diagrams show, in general, good linear correlations that agree with a genetic relationship between the different granitoids, through fractional crystallization of plagioclase, pyroxene, amphibole, oxide minerals and apatite. In primitive mantle-normalized trace element spiderdiagrams, the analysed samples display strong enrichment in LILE compared to HFSE (15.78≤ RbN/YN ≤ 81.96), accompanied by negative anomalies of Nb, Ta and Ti. REE chondrite-normalized plots show moderate LREE enrichment (3.32 ≤ LaN/LuN ≤ 6.36) and slight to strong negative Eu anomalies (0.46 ≤ Eu/Eu* ≤ 0.92). In conclusion, the petrographical and geochemical features show that the Lalezar intrusives fit into I-type granitoids, belong to the calc-alkaline series and probably have been generated in a continental arc setting, which agrees with models previously presented to the U-DVB
PIKES Analysis Reveals Response to Degraders and Key Regulatory Mechanisms of the CRL4 Network
Co-opting Cullin4 RING ubiquitin ligases (CRL4s) to inducibly degrade pathogenic proteins is emerging as a promising therapeutic strategy. Despite intense efforts to rationally design degrader molecules that co-opt CRL4s, much about the organization and regulation of these ligases remains elusive. Here, we establish protein interaction kinetics and estimation of stoichiometries (PIKES) analysis, a systematic proteomic profiling platform that integrates cellular engineering, affinity purification, chemical stabilization, and quantitative mass spectrometry to investigate the dynamics of interchangeable multiprotein complexes. Using PIKES, we show that ligase assemblies of Cullin4 with individual substrate receptors differ in abundance by up to 200-fold and that Cand1/2 act as substrate receptor exchange factors. Furthermore, degrader molecules can induce the assembly of their cognate CRL4, and higher expression of the associated substrate receptor enhances degrader potency. Beyond the CRL4 network, we show how PIKES can reveal systems level biochemistry for cellular protein networks important to drug development
Superconducing Alloys with Weak and Strong Scattering: Anderson's Theorem and a Superconductor-Insulator Transition
We have studied the effects of strong impurity scattering on disordered
superconductors beyond the low impurity concentration limit. By applying the
full CPA to a superconductiong A-B binary alloy, we calculated the fluctuations
of the local order parameters and charge densities,
for weak and strong on site disorder. We find that for narrow
band alloy s-wav e superconductors the conditions for Anderson's theorem are
satisfied in general only for the case of particle-hole symmetry. In this case
it is satisfied regardless whether we are in the weak or strong scattering
regimes. Interestingly, we find that strong scattering leads to band splitting
and in this regime for any band filling we have a critical concentration where
a superconductor-insulator quantum phase transition occurs at T=0.Comment: 28 pages, 13 figure
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