p-wave phase shift and scattering length of 6^6Li

We have calculated the p-wave phase shifts and scattering length of $^6$Li. For this we solve the $p$ partial wave Schr\"odinger equation and analyze the validity of adopting the semiclassical solution to evaluate the constant factors in the solution. Unlike in the $s$ wave case, the semiclassical solution does not provide unique value of the constants. We suggest an approximate analytic solution, which provides reliable results in special cases. Further more, we also use the variable phase method to evaluate the phase shifts. The p-wave scattering lengths of $^{132}$Cs and $^{134}$Cs are calculated to validate the schemes followed. Based on our calculations, the value of the $p$ wave scattering length of $^6$Li is $-45a_o$.Comment: 10 figure

Influence of nearly resonant light on the scattering length in low-temperature atomic gases

We develop the idea of manipulating the scattering length $a$ in low-temperature atomic gases by using nearly resonant light. As found, if the incident light is close to resonance with one of the bound $p$ levels of electronically excited molecule, then virtual radiative transitions of a pair of interacting atoms to this level can significantly change the value and even reverse the sign of $a$. The decay of the gas due to photon recoil, resulting from the scattering of light by single atoms, and due to photoassociation can be minimized by selecting the frequency detuning and the Rabi frequency. Our calculations show the feasibility of optical manipulations of trapped Bose condensates through a light-induced change in the mean field interaction between atoms, which is illustrated for $^7$Li.Comment: 12 pages, 1 Postscript figur

Gene expression studies in Down syndrome: what do they tell us about disease phenotypes?

Down syndrome is a well-studied aneuploidy condition in humans, which is associated with various disease phenotypes including cardiovascular, neurological, haematological and immunological disease processes. This review paper aims to discuss the research conducted on gene expression studies during fetal development. A descriptive review was conducted, encompassing all papers published on the PubMed database between September 1960 and September 2022. We found that in amniotic fluid, certain genes such as COL6A1 and DSCR1 were found to be affected, resulting in phenotypical craniofacial changes. Additionally, other genes such as GSTT1, CLIC6, ITGB2, C21orf67, C21orf86 and RUNX1 were also identified to be affected in the amniotic fluid. In the placenta, dysregulation of genes like MEST, SNF1LK and LOX was observed, which in turn affected nervous system development. In the brain, dysregulation of genes DYRK1A, DNMT3L, DNMT3B, TBX1, olig2 and AQP4 has been shown to contribute to intellectual disability. In the cardiac tissues, dysregulated expression of genes GART, ETS2 and ERG was found to cause abnormalities. Furthermore, dysregulation of XIST, RUNX1, SON, ERG and STAT1 was observed, contributing to myeloproliferative disorders. Understanding the differential expression of genes provides insights into the genetic consequences of DS. A better understanding of these processes could potentially pave the way for the development of genetic and pharmacological therapies

Useful immunohistochemical indicators in canine mast cell tumours

Morphological and immunohistochemical analysis of 45 canine mast cell tumours was performed to determine whether the proteins examined are useful for a more precise description of tumour morphology and a more reliable determination of the prognosis in patients. Tissue sections were stained according to the standard haematoxylin and eosin (HE) technique and with toluidine blue to demonstrate cytoplasmic granules. Immunohistochemical studies were performed, using the cell markers CD117 (c-kit), p16 and von Willebrand factor (FVIII). In CD117 three different staining patterns were observed: (1) membranous reaction, (2) intense staining of cytoplasm, and (3) a diffuse, delicate cytoplasmic reaction. Von Willebrand antibody was evaluated on the basis of the number of blood vessels stained. p16 expression was evaluated by scoring positive nuclear reaction. Positive expression was demonstrated for all examined antigens, but their level of expression differed depending on the grades of tumour malignancy. Statistical analysis of the results documented a pronounced positive correlation between the markers studied and the grade of tumour malignancy (P < 0.001). It was shown that each of the cell markers examined represents a useful prognostic indicator for patients with mast cell tumours. The calculated correlation coefficients demonstrate a strong association between the expressions of CD117, FVIII and p16, and the histological malignancy of a tumour

The Potential of Adaptive Design in Animal Studies

Clinical trials are the backbone of medical research, and are often the last step in the development of new therapies for use in patients. Prior to human testing, however, preclinical studies using animal subjects are usually performed in order to provide initial data on the safety and effectiveness of prospective treatments. These studies can be costly and time consuming, and may also raise concerns about the ethical treatment of animals when potentially harmful procedures are involved. Adaptive design is a process by which the methods used in a study may be altered while it is being conducted in response to preliminary data or other new information. Adaptive design has been shown to be useful in reducing the time and costs associated with clinical trials, and may provide similar benefits in preclinical animal studies. The purpose of this review is to summarize various aspects of adaptive design and evaluate its potential for use in preclinical research

Resonant Coupling in the Heteronuclear Alkali Dimers for Direct Photoassociative Formation of X(0,0) Ultracold Molecules

Promising pathways for photoassociative formation of ultracold heteronuclear alkali metal dimers in their lowest rovibronic levels (denoted X(0,0)) are examined using high quality ab initio calculations of potential energy curves currently available. A promising pathway for KRb, involving the resonant coupling of the $2 ^1\Pi$ and $1 ^1\Pi$ states just below the lowest excited asymptote (K($4s$)+Rb($5p_{1/2}$)), is found to occur also for RbCs and less promisingly for KCs as well. The resonant coupling of the $3 ^1 \Sigma ^+$ and $1 ^1\Pi$ states, also just below the lowest excited asymptote, is found to be promising for LiNa, LiK, LiRb, and less promising for LiCs and KCs. Direct photoassociation to the $1 ^1\Pi$ state near dissociation appears promising in the final dimers, NaK, NaRb, and NaCs, although detuning more than 100 cm$^{-1}$ below the lowest excited asymptote may be required.Comment: 20 pages, 12 figures, Submitted to Journal of Physical Chemistry

Limit on suppression of ionization in metastable neon traps due to long-range anisotropy

This paper investigates the possibility of suppressing the ionization rate in a magnetostatic trap of metastable neon atoms by spin-polarizing the atoms. Suppression of the ionization is critical for the possibility of reaching Bose-Einstein condensation with such atoms. We estimate the relevant long-range interactions for the system, consisting of electric quadrupole-quadrupole and dipole-induced dipole terms, and develop short-range potentials based on the Na_2 singlet and triplet potentials. The auto-ionization widths of the system are also calculated. With these ingredients we calculate the ionization rate for spin-polarized and for spin-isotropic samples, caused by anisotropy of the long-range interactions. We find that spin-polarization may allow for four orders of magnitude suppression of the ionization rate for Ne. The results depend sensitively on a precise knowledge of the interaction potentials, however, pointing out the need for experimental input. The same model gives a suppression ratio close to unity for metastable xenon in accordance with experimental results, due to a much increased anisotropy in this case.Comment: 15 pages including figures, LaTex/RevTex, uses epsfig.st

Theoretical study of the absorption spectra of the lithium dimer

For the lithium dimer we calculate cross sections for absorption of radiation from the vibrational-rotational levels of the ground X [singlet Sigma g +] electronic state to the vibrational levels and continua of the excited A [singlet Sigma u +] and B [singlet Pi u] electronic states. Theoretical and experimental data are used to characterize the molecular properties taking advantage of knowledge recently obtained from photoassociation spectroscopy and ultra-cold atom collision studies. The quantum-mechanical calculations are carried out for temperatures in the range from 1000 to 2000 K and are compared with previous calculations and measurements.Comment: 20 pages, revtex, epsf, 6 fig