Regional and experiential differences in surgeon preference for the treatment of cervical facet injuries: a case study survey with the AO Spine Cervical Classification Validation Group

Purpose: The management of cervical facet dislocation injuries remains controversial. The main purpose of this investigation was to identify whether a surgeon’s geographic location or years in practice influences their preferred management of traumatic cervical facet dislocation injuries. Methods: A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. The survey included clinical case scenarios of cervical facet dislocation injuries and asked responders to select preferences among various diagnostic and management options. Results: A total of 189 complete responses were received. Over 50% of responding surgeons in each region elected to initiate management of cervical facet dislocation injuries with an MRI, with 6 case exceptions. Overall, there was considerable agreement between American and European responders regarding management of these injuries, with only 3 cases exhibiting a significant difference. Additionally, results also exhibited considerable management agreement between those with ≤ 10 and > 10 years of practice experience, with only 2 case exceptions noted. Conclusion: More than half of responders, regardless of geographical location or practice experience, identified MRI as a screening imaging modality when managing cervical facet dislocation injuries, regardless of the status of the spinal cord and prior to any additional intervention. Additionally, a majority of surgeons would elect an anterior approach for the surgical management of these injuries. The study found overall agreement in management preferences of cervical facet dislocation injuries around the globe

Experimental comparison of various excitation and acquisition techniques for modal analysis of violins

All this data is described in the paper to be published: Experimental comparison of various excitation and acquisition techniques for modal analysis of violin

Experimental comparison of various excitation and acquisition techniques for modal analysis of violins

All this data is described in the paper to be published: Experimental comparison of various excitation and acquisition techniques for modal analysis of violin

Experimental comparison of various excitation and acquisition techniques for modal analysis of violins

All this data is described in the paper to be published: Experimental comparison of various excitation and acquisition techniques for modal analysis of violin

Modal Analysis of a Trapezoidal Violin Built after the Description of Félix Savart

One-dimensional experimental modal analysis of an unvarnished trapezoidal violin built after the description of F. Savart and an anonymous trapezoidal violin on display in the Music Instrument Museum of Brussels is described. The analysis has revealed ten prominent modes. A mode that may potentially play a role of the “tonal barometer” of the instrument is pointed out. The mode shapes are symmetric and of high amplitude, due to the construction of the instrument. Subjective evaluation of the sound quality demonstrated no pronounced difference between the trapezoidal violin and normal violin

Three-dimensional quantitative analysis of healthy foot shape: A proof of concept study

Background: Foot morphology has received increasing attention from both biomechanics researches and footwear manufacturers. Usually, the morphology of the foot is quantified by 2D footprints. However, footprint quantification ignores the foot's vertical dimension and hence, does not allow accurate quantification of complex 3D foot shape. Methods: The shape variation of healthy 3D feet in a population of 31 adult women and 31 adult men who live in Belgium was studied using geometric morphometric methods. The effect of different factors such as sex, age, shoe size, frequency of sport activity, Body Mass Index (BMI), foot asymmetry, and foot loading on foot shape was investigated. Correlation between these factors and foot shape was examined using multivariate linear regression. Results: The complex nature of a foot's 3D shape leads to high variability in healthy populations. After normalizing for scale, the major axes of variation in foot morphology are (in order of decreasing variance): arch height, combined ball width and inter-toe distance, global foot width, hallux bone orientation (valgus-varus), foot type (e.g. Egyptian, Greek), and midfoot width. These first six modes of variation capture 92.59% of the total shape variation. Higher BMI results in increased ankle width, Achilles tendon width, heel width and a thicker forefoot along the dorsoplantar axis. Age was found to be associated with heel width, Achilles tendon width, toe height and hallux orientation. A bigger shoe size was found to be associated with a narrow Achilles tendon, a hallux varus, a narrow heel, heel expansion along the posterior direction, and a lower arch compared to smaller shoe size. Sex was found to be associated with differences in ankle width, Achilles tendon width, and heel width. Frequency of sport activity was associated with Achilles tendon width and toe height. Conclusion: A detailed analysis of the 3D foot shape, allowed by geometric morphometrics, provides insights in foot variations in three dimensions that can not be obtained from 2D footprints. These insights could be applied in various scientific disciplines, including orthotics and shoe design.</p

Computational Screening of Nanoporous Materials for Hexane and Heptane Isomer Separation

Computational high-throughput screening was carried out to assess a large number of experimentally reported metal-organic frameworks (MOFs) and zeolites for their utility in hexane isomer separation. Through the work, we identified many MOFs and zeolites with high selectivity (SL+M &gt; 10) for the group of n-hexane, 2-methylpentane, and 3-methylpentane (linear and monobranched isomers) versus 2,2-dimethylbutane and 2,3-dimethylbutane (dibranched isomers). This group of selective sorbents includes VICDOC (Fe2(BDP)3), a MOF with triangular pores that is known to exhibit high isomer selectivity and capacity. For three of these structures, the adsorption isotherms for a 10-component mixture of hexane and heptane isomers were calculated. Subsequent simulations of column breakthrough curves showed that the DEYVUA MOF exhibits a longer process cycle time than VICDOC MOF or MRE zeolite, which are previously reported, high-performing materials, illustrating the importance of capacity in designing MOFs for practical applications. Among the identified candidates, we synthesized and characterized a MOF in a new copper form with high predicted adsorbent capacity (qL+M &gt; 1.2 mol/L) and moderately high selectivity (SL+M ≈ 10). Finally, we examined the role of pore shape in hexane isomer separations, especially of triangular-shaped pores. We show through the potential energy surface and three-dimensional siting analyses that linear alkanes do not populate the corners of narrow triangular channels and that structures with nontriangular pores can efficiently separate hexane isomers. Detailed thermodynamic analysis illustrates how differences in the free energy of adsorption contribute to shape-selective separation in nanoporous materials

Understanding Hydrocarbon Adsorption in the UiO-66 Metal–Organic Framework: Separation of (Un)saturated Linear, Branched, Cyclic Adsorbates, Including Stereoisomers

The low coverage adsorption properties of alkanes, alkenes, and aromatics of the linear, branched, and cyclic type (ca. 70 molecules) were studied using inverse pulse gas chromatography at zero coverage on the zirconium metal–organic framework UiO-66 and its functionalized analogues UiO-66-Me, UiO-66-NO₂, UiO-66-Me₂ in the temperature range 433–573 K. In our study, we determined and analyzed the adsorption enthalpy, Henry constants, and entropic factors. Preferential adsorption of bulky molecules is observed with specific adsorbate and cage size effects, yielding very specific, preferential adsorption. Remarkably high adsorption selectivity factors (up to 14) for cyclo- compared to <i>n-</i>alkanes were found. The presence of additional groups (methyl, nitro) on the linkers in the framework influences adsorption properties significantly, mainly by reducing the effective pore size. Whereas increased selectivity is observed for UiO-66-Me, this effect decreases again upon addition of a second methyl group, UiO-66-Me₂. The latter allows for tuning confinement factors inside the pores, thus adsorption properties of the metal–organic framework. The selective adsorption results from the interaction in the smallest octahedral cage. The extreme confinement in the tetrahedral cage allows for stereoselective separation of disubstituted cycloalkanes and <i>cis</i>/<i>trans</i> alkenes. Monte Carlo simulations were performed for the unfunctionalized UiO-66 framework. First, a comparative study between the force fields Dreiding and UFF is performed with <i>n-</i>alkanes to obtain accurate and reproducible values. The simulations show adsorbate molecular size–adsorbent cage size effects similar to window/cage effects reported for zeolites (e.g., silicalite). Second, adsorption properties were simulated for selected cases, including stereoisomers. Careful analysis of the adsorbate’s molecular positioning in the framework confirms the experimental data. The framework’s selectivity results from adsorption in the tetrahedral cage at zero coverage. Furthermore, simulations show important contributions of entropic factors to the observed adsorption selectivity