Quantum mechanical evolution operator in the presence of a scalar linear potential: discussion on the evolved state

We discuss the form of the wave-function of a state subjected to a scalar linear potential, paying special attention to quantum tunneling. We analyze the phases acquired by the evolved state and show that some of them have a pure quantum mechanical origin. In order to measure one of these phases, we propose a simple experimental scenario. We finally apply the evolution equations to re-analyze the Stern\&Gerlach experiment and to show how to manipulate spin by employing constant electric fields.Comment: in press in Physica Script

Spin effects probed by Rayleigh X-ray scattering off hydrogenic ions

We study the polarization characteristics of x-ray photons scattered by hydrogenic atoms, based on the Dirac equation and second-order perturbation theory. The relativistic states used in calculations are obtained using the finite basis set method and expressed in terms of B-splines and B-polynomials. We derive general analytical expressions for the polarization-dependent total cross sections, which are applicable to any atom and ion, and evaluate them separately for linear and circular polarization of photons. In particular, detailed calculations are performed for the integrated Stokes parameters of the scattered light for hydrogen as well as hydrogenlike neon and argon. Analyzing such integrated Stokes parameters, special attention is given to the electron-photon spin-spin interaction, which mostly stems from the magnetic-dipole contribution of the electron-photon interaction. Subsequently, we find an energy window for the selected targets in which such spin-spin interactions can be probed.Comment: 8 pages,ures 4 fig, To be appeared in Radiat. Phys. Chem. arXiv admin note: text overlap with arXiv:1208.308

Angular and polarization analysis for two-photon decay of 2s hyperfine states of hydrogenlike Uranium

The amplitude of two-photon transitions between hyperfine states in hydrogenlike ions is derived based on relativistic Dirac equation and second order perturbation theory. We study angular and linear polarization properties of the photon pair emitted in the decay of $2s$ states, where spin-flip and non-spin-flip transitions are highlighted. We pay particular attention to hydrogenlike uranium, since it is an ideal candidate for investigating relativistic and high-multipole effects, such as spin-flip transitions. Two types of emission patterns are identified: i) non-spin-flip transitions are found to be characterized by an angular distribution of the type $W(\theta)\sim1+\cos^2\theta$ while the polarizations of the emitted photons are parallel; ii) spin-flip transitions have somewhat smaller decay rates and are found to be characterized by an angular distribution of the type $W(\theta)\sim1-1/3\cos^2\theta$ while the polarizations of the emitted photons are orthogonal, where $\theta$ is the angle between photons directions. Deviations due to non-dipole and relativistic contributions are evaluated for both types of transitions. This work is the first step toward exploring the effect of nucleus over the the angular and polarization properties of the photon pairs emitted by two-photon transitions.Comment: 6 pages, 3 figures,will be published in Phys. Rev. A (2014). arXiv admin note: substantial text overlap with arXiv:1203.660

Relativistic evaluation of the two-photon decay of the metastable {1s}^{2} 2s 2p~^3\mbox{P}_0 state in berylliumlike ions with an active-electron model

The two-photon {1s}^{2} 2s 2p~^3\mbox{P}_0 \rightarrow {1s}^{2} {2s}^2 ^1\mbox{S}_0 transition in berylliumlike ions is theoretically investigated within a full relativistic framework and a second-order perturbation theory. We focus our analysis on how electron correlation, as well as the negative-energy spectrum can affect the forbidden $E1M1$ decay rate. For this purpose we include the electronic correlation by an effective potential and within an active-electron model. Due to its experimental interest, evaluation of decay rates are performed for berylliumlike xenon and uranium. We find that the negative-energy contribution can be neglected in the present decay rate. On the other hand, if contributions of electronic correlation are not carefully taken into account, it may change the lifetime of the metastable state by 20\%. By performing a full-relativistic $jj$-coupling calculation, we found discrepancies for the decay rate of an order of 2 compared to non-relativistic $LS$-coupling calculations, for the selected heavy ions.Comment: 7 pages, 3 page

Quantum Carousel: The Fate of a Bound State Attached to a Linear Rotor

We study the angulon problem -- a linear rotor in a bosonic bath -- in the regime where attractive impurity-boson interactions can support a shallow bound state. To study the fate of the angulon in the vicinity of bound-state formation, we formulate a beyond-linear-coupling model. First, we consider attractive, spherically symmetric impurity-boson interactions for which the linear rotor can be mapped onto a static impurity. The well-known polaron formalism provides an adequate description in this limit. For anisotropic potentials, the presence of a shallow bound state with pronounced anisotropic character leads to a many-body instability that washes out the angulon dynamics

Relationship between sperm quality and total fertilization failure in intracytoplasmic sperm injection and in vitro fertilization cycles: A cross-sectional study

Background: Total fertilization failure (TFF) is associated with essential mechanistic and cellular events. Objective: The present study is a comprehensive examination of detrimental effects with well-known assays for predicting TFF in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles. Materials and Methods: Semen parameters of 90 men, including 60 cases who had experienced IVF/ICSI failure and a control group of 30 individuals, were evaluated. Sperm chromatin/DNA quality assessments were done by aniline blue, toluidine blue, chromomycin A3, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays. A lipid hydroperoxide (LPO) kit was used to measure the LPO, and JC1 staining was used to evaluate mitochondrial membrane potential (MMP). Results: There were statistically significant differences found between the IVF, ICSI and control groups by the toluidine blue (p = 0.01), TUNEL (p = 0.02), and chromomycin A3 (p < 0.001) tests, but not by the aniline blue staining. Furthermore, there was a significant difference regarding LPO concentration and high MMP in cases of IVF fertilization failure compared to the control group (p = 0.04, p = 0.02, respectively). The logistic regression model showed that sperm viability was predictive for fertilization failure in the ICSI group. Sperm chromatin and DNA quality assays were not predictors for TFF in either group. Conclusion: Cellular events such as high DNA fragmentation damage, high levels of reactive oxygen species, and low MMP levels can cause TFF in IVF and ICSI programs. Diagnostic tests, especially in cases with previous fertilization failure, showed significant differences in sperm chromatin and DNA quality between groups but could not predict the risk of TFF. Key words: Intracytoplasmic sperm injection, In vitro fertilization, Reactive oxygen species, Chromatin, DNA fragmentation

Mutation analysis of GJB2 and GJB6 genes and the genetic linkage analysis of five common DFNB loci in the Iranian families with autosomal recessive non-syndrom

The incidence of pre-lingual hearing loss (HL) is about 1 in 1000 neonates. More than 60% of cases are inherited. Non-syndromic HL (NSHL) is extremely heterogeneous: more than 130 loci have been identified so far. The most common form of NSHL is the autosomal recessive form (ARNSHL). In this study, a cohort of 36 big ARNSHL pedigrees with 4 or more patients from 7 provinces of Iran was investigated. All of the families were examined for the presence of GJB2 and GJB6 (del D13S1830 and del D13S1854) mutations using direct sequencing and multiplex PCR methods, respectively. The negative pedigrees for the above-named genes were then tested for the linkage to 5 known loci including DFNB3 (MYO7A), DFNB4 (SLC26A4), DFNB7/11 (TMC1), DFNB21 (TECTA) and DFNB59 (PJVK) by genotyping the corresponding STR markers using PCR and PAGE. Six families had GJB2 mutations. No GJB6 mutation was found. Totally, 3 families showed linkage to DFNB4, 1 family to DFNB7/11 and 1 family to DFNB21. No family was linked to DFNB59. GJB2 included 16.6% of the causes of ARNSHL in our study. In the remaining negative families, DFNB4 accounted for 10% of the causes. Other loci including DFNB7/11 and DFNB21 were each responsible for 3.3% of the etiology. Thus, DFNB1(GJB2) and DFNB4 are the main causes of ARNSHL in our study and GJB6 mutations (del D13S1830, del D13S1854), DFNB3 and DFNB59 were absent. Totally, 30.5% of the ARNSHL etiology was found in this study

Imaging data in COVID-19 patients: focused on echocardiographic findings

To assess imaging data in COVID-19 patients and its association with clinical course and survival and 86 consecutive patients (52 males, 34 females, mean age = 58.8 year) with documented COVID-19 infection were included. Seventy-eight patients (91) were in severe stage of the disease. All patients underwent transthoracic echocardiography. Mean LVEF was 48.1 and mean estimated systolic pulmonary artery pressure (sPAP) was 27.9 mmHg. LV diastolic dysfunction was mildly abnormal in 49 patients (57.6) and moderately abnormal in 7 cases (8.2). Pericardial effusion was present in 5/86 (minimal in size in 3 cases and mild- moderate in 2). In 32/86 cases (37.2), the severity of infection progressed from �severe� to �critical�. Eleven patients (12.8) died. sPAP and computed tomography score were associated with disease progression (P value = 0.002, 0.002 respectively). Tricuspid annular plane systolic excursion (TAPSE) was significantly higher in patients with no disease progression compared with those who deteriorated (P value = 0.005). Pericardial effusion (minimal, mild or moderate) was detected more often in progressive disease (P = 0.03). sPAP was significantly lower among survivors (P value = 0.007). Echocardiographic findings (including systolic PAP, TAPSE and pericardial effusion), total CT score may have prognostic and therapeutic implication in COVID-19 patients. © 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature

Survery of nitrate and nitrite content in distributed red meat in Mazandaran (2008)

, , , , , 1 2 3 (Received 28 September, 2009 ; Accepted 28 December, 2009)AbstractBackground and purpose: Chemical fertilizers which contain nitrite and nitrate ions contaminate water, soil and plants. The livestock are exposed to the ions through grazing in these areas. This study was designed to evaluate the levels of ions in raw sheep and cows meat in Mazandaran and also, to estimate the dietary intake of the ions from fresh meat consumed in a regular diet.Materials and methods: A total of 36 samples of beef and 36 samples of mutton meat were collected from different cities of Mazandaran province (Sari, Babol and Qaemshahr) and their nitrite and nitrate contents were measured by colorimetric Griess Ilosvay method. Data were statistically analyzed by using Mann Whitney.Results: The mean of nitrate and nitrite in mutton was 4/9 and 0/36 and beef was 6/3 and 0/38 mg/kg. Nitrite and nitrate content in beef and mutton had no significant difference.Conclusion: Considering the recommended consumption of meat groups and their substitutes in the food pyramid, which is 6.5 ounce/daily for those who use 2,500 Kcal/day, it is estimated that the amount of nitrate and nitrite consumed by an adult in all meat groups from red meat, the nitrate intake is higher than in some countries such as the UK, although lower than CONTAM Panel is recommended. J Mazand Univ Med Sci 2009; 19(72): 35-41 (Persian)