1,082 research outputs found
Screening for UBE3A gene mutations in a group of Angelman syndrome patients selected according to non-stringent clinical criteria
Abstract.: The Angelman syndrome (AS) is caused by genetic abnormalities affecting the maternal copy of chromosome region 15q12. Until recently, the molecular diagnosis of AS relied on the detection of either a deletion at 15q11-13, a paternal uniparental disomy (UPD) for chromosome 15 or imprinting mutations. A fourth class of genetic defects underlying AS was recently described and consists of mutations of the UBE3A gene. The vast majority of mutations reported so far are predicted to cause major disruptions at the protein level. It is unclear whether mutations with less drastic consequences for the gene product could lead to milder forms of AS. We report on our results obtained by screening 101 clinically diagnosed AS patients for mutations in the UBE3A gene. Non-stringent clinical criteria were purposely applied for inclusion of AS patients in this study. The mutation search was carried out by single-strand conformation polymorphism (SSCP), and SSCP/restriction fragment length polymorphism (RFLP) analyses and revealed five novel UBE3A gene mutations as well as three different polymorphisms. All five mutations were detected in patients with typical features of AS and are predicted to cause frameshifts in four cases and the substitution of a highly conserved residue in the fifth. The results we obtained add to the as yet limited number of reports concerning UBE3A gene mutations. Important aspects that emerge from the data available to date is that the four classes of genetic defects known to underlie AS do not appear to cover all cases. The genetic defect underlying approximately 10% of AS cases, including some familial cases, remains unknow
Sympathetic cooling in a mixture of diamagnetic and paramagnetic atoms
We have experimentally realized a hybrid trap for ultracold paramagnetic
rubidium and diamagnetic ytterbium atoms by combining a bichromatic optical
dipole trap for ytterbium with a Ioffe-Pritchard-type magnetic trap for
rubidium. In this hybrid trap, sympathetic cooling of five different ytterbium
isotopes through elastic collisions with rubidium was achieved. A strong
dependence of the interspecies collisional cross section on the mass of the
ytterbium isotope was observed.Comment: 4 pages, 4 figure
Spatial separation in a thermal mixture of ultracold Yb and Rb atoms
We report on the observation of unusually strong interactions in a thermal
mixture of ultracold atoms which cause a significant modification of the
spatial distribution. A mixture of Rb and Yb with a temperature
of a few K is prepared in a hybrid trap consisting of a bichromatic
optical potential superimposed on a magnetic trap. For suitable trap parameters
and temperatures, a spatial separation of the two species is observed. We infer
that the separation is driven by a large interaction strength between
Yb and Rb accompanied by a large three-body recombination rate.
Based on this assumption we have developed a diffusion model which reproduces
our observations
Lifetime Measurement of the 6s Level of Rubidium
We present a lifetime measurements of the 6s level of rubidium. We use a
time-correlated single-photon counting technique on two different samples of
rubidium atoms. A vapor cell with variable rubidium density and a sample of
atoms confined and cooled in a magneto-optical trap. The 5P_{1/2} level serves
as the resonant intermediate step for the two step excitation to the 6s level.
We detect the decay of the 6s level through the cascade fluorescence of the
5P_{3/2} level at 780 nm. The two samples have different systematic effects,
but we obtain consistent results that averaged give a lifetime of 45.57 +- 0.17
ns.Comment: 10 pages, 9 figure
Production of ultracold heteronuclear YbRb* molecules by photoassociation
We have produced ultracold heteronuclear YbRb molecules in a combined
magneto-optical trap by photoassociation. The formation of electronically
excited molecules close to the dissociation limit was observed by trap loss
spectroscopy in mixtures of Rb with Yb and Yb. The
molecules could be prepared in a series of vibrational levels with resolved
rotational structure, allowing for an experimental determination of the
long-range potential in the electronically excited state
R Markdown: Integrating A Reproducible Analysis Tool into Introductory Statistics
Nolan and Temple Lang argue that âthe ability to express statistical computations is an es- sential skill.â A key related capacity is the ability to conduct and present data analysis in a way that another person can understand and replicate. The copy-and-paste workflow that is an artifact of antiquated user-interface design makes reproducibility of statistical analysis more difficult, especially as data become increasingly complex and statistical methods become increasingly sophisticated. R Markdown is a new technology that makes creating fully-reproducible statistical analysis simple and painless. It provides a solution suitable not only for cutting edge research, but also for use in an introductory statistics course. We present experiential and statistical evidence that R Markdown can be used effectively in introductory statistics courses, and discuss its role in the rapidly-changing world of statistical computation
Synthesis, Crystal Structure, and Spectral Characteristics of N-(tert-Butyl) aminomethanesulfonic Acid
A new method of the synthesis of N-(tert-butyl)aminomethanesulfonic acid in the system SO2â(CH3)3CNH2âCH2OâH2O was developed. The target compound [(CH3)3ĐĄ]NHCH2SO3H was characterized by means of X-ray diffraction analysis, IR spectroscopy, and mass spectrometry
Synthesis, Crystal Structure, Vibrational Spectra, and Thermochemical Transformations of Tris(hydroxymethyl)aminomethane
AbstractâA practically promising compound, tris(hydroxymethyl)aminomethane sulfate ((TRISH)2SO4,
C8H24N2O10S) was synthesized and studied by a set of experimental methods (elemental analysis, IR and
Raman spectroscopy, mass spectrometry, thermogravimetry)
Products of Interaction between Sulfur(IV) Oxide and Aqueous Solutions of Hexamethylendiamine and tertButylamine: The Crystal Structure of Hexamethylenediammonium Sulfate Dihydrate
The possibility of mild SO2 oxidation in sulfur(IV) oxideâalkylamineâwaterâoxygen systems is demonstrated to yield onium sulfates
Interaction Products in the System Sulfur Dioxideâ2,2âČ-BipyridineâWater. Van der Waals Clathrates
Crystallization of 2,2âČ-bipyridine from aqueous solution containing sulfur(IV) oxide afforded clathrates with the composition (bipy)k·(SO2)m·(H2O)n. X-Ray amorphous guest SO2 molecules occupy voids in the crystal lattice of 2,2âČ-bipyridine without distortion of its structure. The isolated compounds were
characterized by elemental analyses, X-ray diffraction data, and IR, NMR, and mass spectra
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