Evaluation of geometric tortuosity for 3D digitally generated porous media considering the pore size distribution and the A-star algorithm.

Porous materials are of great interest in multiple applications due to their usefulness in energy conversion devices and their ability to modify structural and diffusive properties. Geometric tortuosity plays an important role in characterizing the complexity of a porous medium. The literature on several occasions has related it as a parameter dependent on porosity only.

Influence of bending pre-load on the tensile response of the lumbar spine.

Previous full body cadaver testing has shown that both obliquely oriented seats in survivable aircraft crashes and far-side oblique crashes in vehicles present distinctive occupant kinematics that are not yet well understood. Knowledge surrounding how these loading scenarios affect the lumbar spine is particularly lacking as there exists minimal research concerning oblique loading. The current study was created to evaluate a novel experimental method through comparison with existing literature, and to examine the impact of a static bending pre-load (posture) on the load-displacement response for the whole lumbar spine loaded in non-destructive axial distraction.

A novel posture control device to induce high-rate complex loads for spine biomechanical studies.

Modern environmental scenarios such as autonomous vehicles, aircrafts, and military vehicles position the human body in a nonstandard posture and induce multiplanar loads; however, current spine alignment methods and loading are based on sagittal and planar loads. The objective of this study is to develop a posture control device and demonstrate its ability to induce multiplanar loads to the human cadaver spinal columns. The inferior end of the device was designed to allow a full six degree-of-freedom control for positioning the specimen via a coupled x-y cross table, vertical lift platform, and triaxial rotation mechanism.

Mapping the kinetic and thermodynamic landscape of formaldehyde oligomerization under neutral conditions.

Density functional theory calculations, including Poisson-Boltzmann implicit solvent and free energy corrections, are applied to study the thermodynamic and kinetic free energy landscape of formaldehyde oligomerization up to the C4 species in aqueous solution at pH 7. Oligomerization via C-O bond formation leads to linear polyoxymethylene (POM) species, which are the most kinetically accessible oligomers and are marginally thermodynamically favored over their oxane ring counterparts. On the other hand, C-C bond formation via aldol reactions leads to sugars that are thermodynamically much more stable in free energy than POM species; however, the barrier to dimerization is very high.

Glycolaldehyde monomer and oligomer equilibria in aqueous solution: comparing computational chemistry and NMR data.

A computational protocol utilizing density functional theory calculations, including Poisson-Boltzmann implicit solvent and free energy corrections, is applied to study the thermodynamic and kinetic energy landscape of glycolaldehyde in solution. Comparison is made to NMR measurements of dissolved glycolaldehyde, where the initial dimeric ring structure interconverts among several species before reaching equilibrium where the hydrated monomer is dominant. There is good agreement between computation and experiment for the concentrations of all species in solution at equilibrium, that is, the calculated relative free energies represent the system well.

PVRL1 variants contribute to non-syndromic cleft lip and palate in multiple populations.

Poliovirus Receptor Like-1 (PVRL1) is a member of the immunoglobulin super family that acts in the initiation and maintenance of epithelial adherens junctions and is mutated in the cleft lip and palate/ectodermal dysplasia 1 syndrome (CLPED1, OMIM #225000). In addition, a common non-sense mutation in PVRL1 was discovered more often among non-syndromic sporadic clefting cases in Northern Venezuela in a previous case-control study. The present work sought to ascertain the role of PVRL1 in the sporadic forms of orofacial clefting in multiple populations.

Candidate genes for oral-facial clefts in Guatemalan families.

Nonsyndromic cleft lip +/- cleft palate (CL/P) is a complex trait of unknown etiology. Most genetic studies of CL/P define affection status in a way that ignores subtle subclinical manifestations, resulting in a potential loss of statistical power. This study investigated 10 candidate genes in 155 individuals from 25 Guatemalan CL/P families.

Medical sequencing of candidate genes for nonsyndromic cleft lip and palate.

Nonsyndromic or isolated cleft lip with or without cleft palate (CL/P) occurs in wide geographic distribution with an average birth prevalence of 1/700. We used direct sequencing as an approach to study candidate genes for CL/P. We report here the results of sequencing on 20 candidate genes for clefts in 184 cases with CL/P selected with an emphasis on severity and positive family history.