Sequencing the maize genome

Sequencing of complex genomes can be accomplished by enriching shotgun libraries for genes. In maize, gene-enrichment by copy-number normalization (high C(0)t) and methylation filtration (MF) have been used to generate up to two-fold coverage of the gene-space with less than 1 million sequencing reads. Simulations using sequenced bacterial artificial chromosome (BAC) clones predict that 5x coverage of gene-rich regions, accompanied by less than 1x coverage of subclones from BAC contigs, will generate high-quality mapped sequence that meets the needs of geneticists while accommodating unusually high levels of structural polymorphism. By sequencing several inbred strains, we propose a strategy for capturing this polymorphism to investigate hybrid vigor or heterosis

The distance upon contact: Determination from roughness profile

The point at which two random rough surfaces make contact takes place at the contact of the highest asperities. The distance upon contact d_0 in the limit of zero load has crucial importance for determination of dispersive forces. Using gold films as an example we demonstrate that for two parallel plates d_0 is a function of the nominal size of the contact area L and give a simple expression for d_0(L) via the surface roughness characteristics. In the case of a sphere of fixed radius R and a plate the scale dependence manifests itself as an additional uncertainty \delta d(L) in the separation, where the scale L is related with the separation d via the effective area of interaction L^2\sim\pi Rd. This uncertainty depends on the roughness of interacting bodies and disappears in the limit L\to \infty.Comment: 5 pages, 4 figures, to be published in PR

Body-assisted van der Waals interaction between two atoms

Using fourth-order perturbation theory, a general formula for the van der Waals potential of two neutral, unpolarized, ground-state atoms in the presence of an arbitrary arrangement of dispersing and absorbing magnetodielectric bodies is derived. The theory is applied to two atoms in bulk material and in front of a planar multilayer system, with special emphasis on the cases of a perfectly reflecting plate and a semi-infinite half space. It is demonstrated that the enhancement and reduction of the two-atom interaction due to the presence of a perfectly reflecting plate can be understood, at least in the nonretarded limit, by using the method of image charges. For the semi-infinite half space, both analytical and numerical results are presented.Comment: 17 pages, 9 figure

Examining the patient and caregiver experience with diazepam nasal spray for seizure clusters: Results from an exit survey of a phase 3, open-label, repeat-dose safety study

BACKGROUND: Ideal rescue treatments for acute treatment of seizure clusters should be easy to administer, so it is important to assess user perceptions of these treatments. Diazepam nasal spray is designed to have a rapid, noninvasive, and socially acceptable route of administration. Patient and caregiver (including care partner) responses to surveys from a phase 3 safety study of diazepam nasal spray are reported. METHODS: The study enrolled patients aged 6-65 years with seizure clusters. Surveys distributed to patients and caregivers at study end, completion, or discontinuation collected data on comfort using diazepam nasal spray outside the home, timing of administration and return to their usual selves, and comfort of use compared with rectal diazepam. Safety was assessed. RESULTS: Of 175 patients enrolled at the October 31, 2019, interim cutoff, 158 received diazepam nasal spray. Sixty-seven (42.4%) patients and 84 (53.2%) caregivers responded to the surveys (including 35 matched pairs). Most patients (78.8%, 52/66) responded that they were very comfortable doing activities outside the home with diazepam nasal spray available; 59.4% of patients returned to their usual selves within an hour of administration. Twenty-seven (40.3%) of these patients reported self-administration, 48% doing so at the first sign of a seizure. Administration of diazepam nasal spray was rated extremely or very easy by 93.8% of caregivers. Safety profile was consistent with diazepam rectal gel; no patient discontinued owing to treatment-emergent adverse events. Nasal discomfort was typically mild and transient. Among patients who had used diazepam rectal gel, most were not at all comfortable using it outside the home (86.7%) or at home (64.5%) compared with diazepam nasal spray, whereas caregivers reported that diazepam rectal gel was not at all easy to use compared with diazepam nasal spray. CONCLUSIONS: This survey from the phase 3 safety study of diazepam nasal spray shows that patients and caregivers were satisfied with, and more comfortable using, diazepam nasal spray than rectal diazepam in public. NCT02721069

Rolling friction of a viscous sphere on a hard plane

A first-principle continuum-mechanics expression for the rolling friction coefficient is obtained for the rolling motion of a viscoelastic sphere on a hard plane. It relates the friction coefficient to the viscous and elastic constants of the sphere material. The relation obtained refers to the case when the deformation of the sphere $\xi$ is small, the velocity of the sphere $V$ is much less than the speed of sound in the material and when the characteristic time $\xi/V$ is much larger than the dissipative relaxation times of the viscoelastic material. To our knowledge this is the first ``first-principle'' expression of the rolling friction coefficient which does not contain empirical parameters.Comment: 6 pages, 2 figure

Anomalous density dependence of static friction in sand

We measured experimentally the static friction force $F_s$ on the surface of a glass rod immersed in dry sand. We observed that $F_s$ is extremely sensitive to the closeness of packing of grains. A linear increase of the grain-density yields to an exponentially increasing friction force. We also report on a novel periodicity of $F_s$ during gradual pulling out of the rod. Our observations demonstrate the central role of grain bridges and arches in the macroscopic properties of granular packings.Comment: plain tex, 6 pages, to appear in Phys.Rev.

Future Opportunities for Research in Rescue Treatments

Clinical studies of rescue medications for seizure clusters are limited and are designed to satisfy regulatory requirements, which may not fully consider the needs of the diverse patient population that experiences seizure clusters or utilize rescue medication. The purpose of this narrative review is to examine the factors that contribute to, or may influence the quality of, seizure cluster research with a goal of improving clinical practice. We address five areas of unmet needs and provide advice for how they could enhance future trials of seizure cluster treatments. The topics addressed in this article are: (1) unaddressed end points to pursue in future studies, (2) roles for devices to enhance rescue medication clinical development programs, (3) tools to study seizure cluster prediction and prevention, (4) the value of other designs for seizure cluster studies, and (5) unique challenges of future trial paradigms for seizure clusters. By focusing on novel end points and technologies with value to patients, caregivers, and clinicians, data obtained from future studies can benefit the diverse patient population that experiences seizure clusters, providing more effective, appropriate care as well as alleviating demands on health care resources