171 research outputs found
Renal Cell Carcinoma Presenting as Metastasis to Scrotum and Spermatic Cord
Unusual site metastasis as presenting complaint of renal cell carcinoma (RCC) has been reported previously in literature. RCC is a notorious tumor with unpredictable behavior. We present a case of RCC who presented with scrotal mass and on subsequent investigation was found to have metastasis to scrotum and spermatic cord. Both testes were normal with no evidence of metastasis
Stochastic Methods to Find Maximum Likelihood for Spam E-mail Classification
The increasing volume of unsolicited bulk e-mails leads to the need for reliable stochastic spam detection methods for the classification of the received sequence of e-mails. When a sequence of emails is received by a recipient during a time period, the spam filters have already classified them as spam or not spam. Due to the dynamic nature of the spam, there might be emails marked as not spam but are actually real spams and vice versa. For the sake of security, it is important to be able to detect real spam emails. This paper utilizes stochastic methods to refine the preliminary spam detection and to find maximum likelihood for spam e-mail classification. The method is based on the Bayesian theorem, hidden Markov model (HMM), and the Viterbi algorithm
Model of orbital populations for voltage-controlled magnetic anisotropy in transition-metal thin films
Voltage-controlled magnetic anisotropy (VCMA) is an efficient way to manipulate the magnetization states in nanomagnets and is promising for low-power spintronic applications. The underlying physical mechanism for VCMA is known to involve a change in the d orbital occupation on the transition-metal interface atoms with an applied electric field. However, a simple qualitative picture of how this occupation controls the magnetocrystalline anisotropy (MCA) and even why in certain cases the MCA has the opposite sign remains elusive. In this paper, we exploit a simple model of orbital populations to elucidate a number of features typical for the interface MCA, and the effect of the electric field on it, for 3d transition-metal thin films used in magnetic tunnel junctions. We find that in all considered cases, including the Fe(001) surface, clean Fe1−xCox (001)/MgO interface, and oxidized Fe(001)/MgO interface, the effects of alloying and the electric field enhance the MCA energy with electron depletion, which is largely explained by the occupancy of the minority-spin dxz,yz orbitals. However, the hole-doped Fe(001) exhibits an inverse VCMA in which the MCA enhancement is achieved when electrons are accumulated at the Fe (001)/MgO interface with the applied electric field. In this regime, we predict a significantly enhanced VCMA that exceeds 1 pJ/Vm. Realizing this regime experimentally may be favorable for the practical purpose of voltage-driven magnetization reversal
Model of orbital populations for voltage-controlled magnetic anisotropy in transition-metal thin films
Voltage-controlled magnetic anisotropy (VCMA) is an efficient way to manipulate the magnetization states in nanomagnets and is promising for low-power spintronic applications. The underlying physical mechanism for VCMA is known to involve a change in the d orbital occupation on the transition-metal interface atoms with an applied electric field. However, a simple qualitative picture of how this occupation controls the magnetocrystalline anisotropy (MCA) and even why in certain cases the MCA has the opposite sign remains elusive. In this paper, we exploit a simple model of orbital populations to elucidate a number of features typical for the interface MCA, and the effect of the electric field on it, for 3d transition-metal thin films used in magnetic tunnel junctions. We find that in all considered cases, including the Fe(001) surface, clean Fe1−xCox (001)/MgO interface, and oxidized Fe(001)/MgO interface, the effects of alloying and the electric field enhance the MCA energy with electron depletion, which is largely explained by the occupancy of the minority-spin dxz,yz orbitals. However, the hole-doped Fe(001) exhibits an inverse VCMA in which the MCA enhancement is achieved when electrons are accumulated at the Fe (001)/MgO interface with the applied electric field. In this regime, we predict a significantly enhanced VCMA that exceeds 1 pJ/Vm. Realizing this regime experimentally may be favorable for the practical purpose of voltage-driven magnetization reversal
Experimental evidence of strong phonon scattering in isotopical disordered systems: The case of LiH_xD_{1-x} crystals
The observation of the local - mode vibration, the two - mode behavior of the
LO phonons at large isotope concentration, as well as large line broadening in
LIH - D mixed crystals directly evidence strong additional phonon scattering
due to the isotope - induced disorder.Comment: 9 pages, 4 figure
Magnetic Moment Softening and Domain Wall Resistance in Ni Nanowires
Magnetic moments in atomic scale domain walls formed in nanoconstrictions and
nanowires are softened which affects dramatically the domain wall resistance.
We perform ab initio calculations of the electronic structure and conductance
of atomic-size Ni nanowires with domain walls only a few atomic lattice
constants wide. We show that the hybridization between noncollinear spin states
leads to a reduction of the magnetic moments in the domain wall. This magnetic
moment softening strongly enhances the domain wall resistance due to scattering
produced by the local perturbation of the electronic potential.Comment: 4 pages, 5 figure
Spin blockade in ferromagnetic nanocontacts
Using a free-electron model and a linear response theory we investigate spin-dependent electronic transport in magnetic nanocontacts in the ballistic regime of conduction. We emphasize the fact that in atomic-size ferromagnetic contacts it is possible to achieve the conductance value of e2/h, which implies a fully spin-polarized electric current. We explore some consequences of this phenomenon. In particular, we show that the presence of a nonmagnetic region in the nanocontact separating two ferromagnetic electrodes can lead to a spin blockade resulting in very large values of magnetoresistance
Testosterone levels in men with type 2 diabetes mellitus
Background: To study testosterone levels in men with type 2 diabetes mellitus in age group of 30-50 years.Methods: In this cross sectional study of 193 type 2 diabetes men aged between 30-50 years, total and free testosterone levels were calculated along with other relevant clinical variables like hypertension, BMI, dyslipidemia, peripheral neuropathy, retinopathy.Results: The study group had study out of 193 patients 34.7% have low total testosterone levels, 29.53% have low free testosterone levels and 23.3% have both low and free testosterone levels. Maximum number of patients with low total testosterone levels were in the age group between 46-50 years (41.0%) and with low free total testosterone levels were in the age group between 36-40 years (41.8%).Conclusions: Type 2 diabetes mellitus is associated with low levels of total and free testosterone. Obesity and dyslipidemia are also associated with low testosterone levels
Ferroelectric Instability under Screened Coulomb Interactions
We explore the effect of charge carrier doping on ferroelectricity using
density functional calculations and phenomenological modeling. By considering a
prototypical ferroelectric material, BaTiO3, we demonstrate that ferroelectric
displacements are sustained up to the critical concentration of 0.11 electron
per unit cell volume. This result is consistent with experimental observations
and reveals that the ferroelectric phase and conductivity can coexist. Our
investigations show that the ferroelectric instability requires only a
short-range portion of the Coulomb force with an interaction range of the order
of the lattice constant. These results provide a new insight into the origin of
ferroelectricity in displacive ferroelectrics and open opportunities for using
doped ferroelectrics in novel electronic devices.Comment: 4 pages, 5 figures with 5 pages of supplementary materia
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