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Abstract: The treatment of peripheral nerve injuries with nerve gaps largely consists of autologous nerve grafting utilizing sensory nerve donors. Underlying this clinical practice is the assumption that sensory autografts provide a suitable substrate for motoneuron regeneration, thereby facilitating motor endplate reinnervation and functional recovery. This study examined the role of nerve graft modality on axonal regeneration, comparing motor nerve regeneration through motor, sensory, and mixed nerve isografts in the Lewis rat. A total of 100 rats underwent grafting of the motor or sensory branch of the femoral nerve with histomorphometric analysis performed after 5, 6, or 7 weeks. Analysis demonstrated similar nerve regeneration in motor, sensory, and mixed nerve grafts at all three time points. These data indicate that matching of motor-sensory modality in the rat femoral nerve does not confer improved axonal regeneration through nerve isografts. [Copyright &y& Elsevier]

Abstract: An increase in arousal in response to hypercapnia [elevated arterial PCO2 (partial pressure of CO2) levels] during awake or sleep states is an important component of mechanisms designed to maintain acid–base homeostasis. Since central histaminergic neurons are crucial for maintaining waking states and vigilance, a nonresponsive or dysfunctional histaminergic system could contribute to the lack of arousal in response to hypercapnia in some sleep-related disorders [e.g., sudden infant death syndrome (SIDS) and Ondine''s curse]. Therefore, the present study attempted to determine if histaminergic neurons display functional responses to acute exposure to hypercapnic gas (i.e., gas with elevated CO2 concentrations). Healthy adult male rats were placed in flow cages during the light cycle, or inactive phase, and exposed to either atmospheric air or to environmental CO2 concentrations increasing from baseline up to 20% CO2 over a 5-min period. The expression of the protein product of the immediate-early gene c-fos was used as a measure of functional cellular responses within subpopulations of histaminergic neurons. Among the histaminergic subgroups (E1–E5), only the ventral tuberommamillary nucleus (VTMn)/E2 cell group showed significant increases in c-Fos expression following brief exposure to hypercapnic gas. These data are consistent with the hypothesis that histaminergic neuronal cell groups are heterogeneous and are involved in physiological and/or behavioral responses to acute hypercapnic challenge, potentially increasing vigilance during active waking and awakening from sleep during hypercapnic states. [Copyright &y& Elsevier]

• The Recovery-assisted DG method achieves superior accuracy compared to the conventional DG approach for advection-diffusion problems. • The proposed approach maintains a compact computational stencil. • The proposed approach allows larger timestep sizes than a conventional DG approach. • Resolving efficiency analysis demonstrates the new approach's superior accuracy across a broad range of element Peclet numbers. The discontinuous Galerkin (DG) method has been recognized as a promising approach for high-fidelity numerical simulations of turbulent flows (e.g., large-eddy simulation or direct numerical simulation), given its capability to achieve high-order accuracy in complex geometries while damping out spurious high-wavenumber oscillations in advection-dominated regimes. In this work, we analyze an advection-diffusion scheme arising from the strategic use of the Recovery concept to improve the performance of the basic DG spatial discretization on a nearest-neighbors stencil. Following the principle of Recovery, the underlying solution between two neighboring cells is reconstructed in an interface-centered fashion to compute the convective and diffusive fluxes with exceptional accuracy. While certain Recovery-based schemes are known to achieve exceedingly high convergence rates for diffusion (up to 3 p + 2 in the cell-average norm, where p is the degree of the polynomial basis), there are more constraining order of accuracy limitations for advection due to the direction of the wind. The key technical challenge we address is to develop an advection-diffusion scheme that is both stable and efficient while leveraging the high accuracy of the Recovery concept on a nearest-neighbors stencil. The usage of Recovery overcomes a fundamental deficiency in typical DG discretizations, namely that a conventional advection-diffusion scheme is reduced from order 2 p + 1 accuracy in the advection-dominated regime to order 2 p accuracy in the diffusion-dominated regime, as demonstrated by Fourier analysis. Our new Recovery-assisted scheme is instead able to achieve order 2 p + 2 accuracy in both the advection-dominated and diffusion-dominated regimes on the nearest-neighbors stencil. By combining the Recovery operator with the mixed formulation, the proposed advection-diffusion scheme achieves improved accuracy compared to established mixed formulation approaches while circumventing the differentiation of the recovered solution, which is a liability in multi-dimensional geometries. Fourier analysis and a suite of linear and nonlinear test problems, including 3D compressible Navier-Stokes, are presented to examine the performance of the new Recovery-assisted scheme; the results show a considerable accuracy advantage compared to a conventional, state-of-the-art DG approach. Furthermore, to simplify the implementation, we show that the Recovery procedure can be recast as a set of derivative-based correction terms, which replicates the Recovery operator on structured meshes while avoiding the traditional complexities of the Recovery operation. [ABSTRACT FROM AUTHOR]

We introduce a new family of schemes, labeled Compact Gradient Recovery (CGR), for handling parabolic partial differential equations within the discontinuous Galerkin (DG) framework, with as the ultimate goal the discretization of diffusive flux terms in advection-diffusion systems such as the compressible Navier-Stokes equations. Like other DG approaches for diffusion, this family of schemes is based on the mixed formulation, where an auxiliary variable is introduced (but not stored between timesteps) to approximate the solution gradient. To maximize accuracy, wherever interface approximations are necessary within the mixed formulation, our schemes apply the Recovery concept originally introduced by Van Leer and Nomura [1]. However, unlike Recovery DG, our new family of schemes is based on a nearest-neighbor stencil and does not require differentiation of the recovered solution, which can introduce large errors for shear diffusion problems. By design, the new schemes fill the void between the highly accurate Recovery DG schemes and existing mixed-form and penalty-based formulations. Fourier analysis is performed on Cartesian and simplex meshes to determine the order of accuracy and timestep-size stability limits for different solution polynomial orders p. Similar to other DG approaches for diffusion, our proposed schemes make use of a jump penalization factor when solving for the gradient along interfaces; the effect of this parameter is explored through Fourier analysis, allowing an informed recommendation regarding its value. In addition to exploration of the new scheme, the analysis includes previously unknown properties of the widely used BR2 scheme under a broad set of configurations. Our new approach is verified using a comprehensive suite of test problems (scalar Laplacian diffusion, shear diffusion, and compressible Navier-Stokes) on different mesh types and compared to the gold-standard, nearest-neighbor approach for diffusion, the BR2 scheme; our new scheme performs favorably with regard to accuracy of the solution, accuracy of the solution gradient, and timestep size without a substantial increase in computational cost. • We introduce CGR, a novel discontinuous Galerkin approach for parabolic PDEs. • The new approach bridges the gap between Recovery DG and traditional DG methods. • Improved accuracy is demonstrated in the numerical solution and its gradient. [ABSTRACT FROM AUTHOR]

Abstract: The ternary nitrides, Ca4TiN4 and Ca5NbN5, were synthesized in sealed niobium tubes using lithium nitride as a flux at 900 and 1050°C, respectively. The structures of both compounds were solved from single-crystal X-ray diffraction data. Ca4TiN4 is the first example of a calcium group IV nitride; it crystallizes in the triclinic space group (No. 2) with cell parameters a=5.9757(5) Å, b=6.0129(5) Å, c=6.0116(12) Å, α=71.565(4)°, β=79.471(4)°, γ=68.258(4)° and . Ca4TiN4 is isostructural with Na4TiO4 and contains tetrahedral TiN4 units connected through edges and corners to CaN4 tetrahedra and CaN5 square pyramids. Ca5NbN5 crystallizes in the monoclinic space group C2/m (No. 12) with cell parameters a=11.922(7) Å, b=6.878(5) Å, c=8.936(7) Å, β=101.22(3)° and Z=4. Ca5NbN5 is isostructural with Ba5NbN5; the structure contains NbN4 tetrahedra that share vertices with CaN5 trigonal bipyramids. [Copyright &y& Elsevier]

Abstract: We show that the affinity electrophoresis analysis of RNA–small molecule interactions can be made quantifiable by cross-linking the ligand to the gel matrix. Using an RNA–aminoglycoside model system to verify our method, we attached an acryloyl chloride molecule to the aminoglycosides paromomycin and neomycin B to synthesize an acrylamide–aminoglycoside monomer. This molecule was then used as a component in gel polymerization for affinity electrophoresis, covalently attaching an aminoglycoside molecule to the gel matrix. To test RNA binding to the cross-linked aminoglycosides, we used the aminoglycoside binding RNA molecule derived from thymidylate synthase messenger RNA (mRNA) that contains a C–C mismatch. Binding is indicated by the difference in RNA mobility between gels with cross-linked ligand, with ligand embedded during polymerization, and with no ligand present. Critically, the predicted straight line relationship between the reciprocal of the relative migration of the RNA and the ligand concentration is obtained when using cross-linked aminoglycosides, whereas a straight line is not obtained using embedded aminoglycosides. Average apparent dissociation constants are determined from the slope of the line from these plots. This method allows an easy quantitative comparison between different nucleic acid molecules for a small molecule ligand. [Copyright &y& Elsevier]

Abstract: Repair of large nerve defects with acellular nerve allografts (ANAs) is an appealing alternative to autografting and allotransplantation. ANAs have been shown to be similar to autografts in supporting axonal regeneration across short gaps, but fail in larger defects due to a poorly-understood mechanism. ANAs depend on proliferating Schwann cells (SCs) from host tissue to support axonal regeneration. Populating longer ANAs places a greater proliferative demand on host SCs that may stress host SCs, resulting in senescence. In this study, we investigated axonal regeneration across increasing isograft and ANA lengths. We also evaluated the presence of senescent SCs within both graft types. A sciatic nerve graft model in rats was used to evaluate regeneration across increasing isograft (~autograft) and ANA lengths (20, 40, and 60mm). Axonal regeneration and functional recovery decreased with increased graft length and the performance of the isograft was superior to ANAs at all lengths. Transgenic Thy1-GFP rats and qRT-PCR demonstrated that failure of the regenerating axonal front in ANAs was associated with increased levels of senescence related markers in the graft (senescence associated β-galactosidase, p16INK4A, and IL6). Lastly, electron microscopy (EM) was used to qualitatively assess senescence-associated changes in chromatin of SCs in each graft type. EM demonstrated an increase in the presence of SCs with abnormal chromatin in isografts and ANAs of increasing graft length. These results are the first to suggest that SC senescence plays a role in limited axonal regeneration across nerve grafts of increasing gap lengths. [Copyright &y& Elsevier]

Abstract: This study uses the saphenous nerve crush model in Thy1-YFP mice and serial transcutaneous imaging to evaluate the rate of nerve regeneration under various FK-506 (tacrolimus) dosing regimens and in the presence of transgenic overexpression of glial cell line-derived neurotrophic factor (GDNF). Thy1-YFP transgenic mice received saphenous nerve crush and were monitored for axonal regeneration via transcutaneous imaging for 7days. Group A received no FK-506. Groups B and C received FK-506 at 2 or 0.5mg/kg/day, starting three days before injury (preload). Groups D and E received FK-506 at 2 or 0.5mg/kg/day, starting on the day of injury. Group F consisted of double transgenic mice with central overexpression of GDNF by CNS astrocytes (GFAP-GDNF/Thy1-YFP). Length and rate of axonal regeneration were measured and calculated over time. Regardless of concentration, FK-506 preload (Groups B and C) improved length and rate of axonal outgrowth compared with controls (Group A) and no preload (Groups D and E). Surprisingly, central overexpression of GDNF (GFAP-GDNF) delayed and stunted axonal outgrowth. Saphenous nerve crush in Thy1-YFP mice represents a viable model for timely evaluation of therapeutic strategies affecting the rate of nerve regeneration. FK-506 administered three days prior to injury accelerates axonal regeneration beyond injury conditioned regeneration alone and may serve as a reliable positive control for the model. GDNF overexpression in the CNS impedes early axonal outgrowth. [Copyright &y& Elsevier]

Abstract: We have developed an affinity electrophoresis method to screen for RNA–ligand interactions. Native polyacrylamide gels were polymerized in the absence and presence of different RNA binding molecules. Binding is indicated by a difference in mobility between the gel with ligand present and the gel with no ligand present. The utility of this method was demonstrated using the known interaction between the Escherichia coli ribosomal A-site RNA and different aminoglycoside ligands. The RNA–aminoglycoside interaction observed is dose dependent, and the affinity mirrors what is observed in solution. In addition, we used this method to gauge the affinity to different aminoglycoside molecules of an RNA molecule derived from the thymidylate synthase mRNA construct that contains a CC mismatch. [ABSTRACT FROM AUTHOR]

Abstract: Host Schwann cell (SC) migration into nerve allografts is the limiting factor in the duration of immunosuppression following peripheral nerve allotransplantation, and may be affected by different immunosuppressive regimens. Our objective was to compare SC migration patterns between clinical and experimental immunosuppression regimens both over time and at the harvest endpoint. Eighty mice that express GFP under the control of the Schwann cell specific S100 promoter were engrafted with allogeneic, nonfluorescent sciatic nerve grafts. Mice received immunosuppression with either tacrolimus (FK506), or experimental T-cell triple costimulation blockade (CSB), consisting of CTLA4-immunoglobulin fusion protein, anti-CD40 monoclonal antibody, and anti-inducible costimulator monoclonal antibody. Migration of GFP-expressing host SCs into wild-type allografts was assessed in vivo every 3weeks until 15weeks postoperatively, and explanted allografts were evaluated for immunohistochemical staining patterns to differentiate graft from host SCs. Immunosuppression with tacrolimus exhibited a plateau of SC migration, characterized by significant early migration (< 3weeks) followed by a constant level of host SCs in the graft (15weeks). At the endpoint, graft fluorescence was decreased relative to surrounding host nerve, and donor SCs persisted within the graft. CSB-treated mice displayed gradually increasing migration of host SCs into the graft, without the plateau noted in tacrolimus-treated mice, and also maintained a population of donor SCs at the 15-week endpoint. SC migration patterns are affected by immunosuppressant choice, particularly in the immediate postoperative period, and the use of a single treatment of CSB may allow for gradual population of nerve allografts with host SCs. [ABSTRACT FROM AUTHOR]

Abstract: Background: Ipratropium and albuterol, combined in a single formulation, is widely used as three to four times daily maintenance therapy in COPD. This trial compared tiotropium, once daily, as a potential alternative to patients already taking the ipratropium/albuterol combination. Methods: 676 patients with moderate to very severe stable COPD (mean FEV1 =39% of predicted) maintained on ipratropium/albuterol were randomized to receive over an 84 day period either tiotropium (18mcg) each morning, or continue with ipratropium (26mcg)/albuterol (206mcg), 2 actuations 4 times daily, using a parallel group, double-blind, double-dummy design. Six-hour spirometry was assessed on study days 1, 22, and 84, along with safety assessments and other efficacy measures. Results: In terms of primary outcomes, mean trough FEV1 at 84 days was larger in the tiotropium arm, as compared with the ipratropium/albuterol arm (difference=86ml; 95% CI, 49 to 123ml, p <0.0001). The mean FEV1 AUC0–6 at 84 days was also larger in the tiotropium arm (difference=17ml; 95% CI, −21 to 56ml), this difference being statistically non-inferior to the ipratropium/albuterol arm (p <0.001), but not statistically superior (p =0.37). Other efficacy measures were similar in the two groups. Lower respiratory adverse events were reported in 40 tiotropium patients vs. 52 ipratropium/albuterol patients. Safety reporting was otherwise similar. Conclusion: Patients previously maintained on the ipratropium/albuterol combination taken four times daily can be switched to tiotropium once daily with the reasonable expectation of at least equivalent bronchodilation during daytime hours and superior bronchodilation during early morning hours. [Copyright &y& Elsevier]

Abstract: Background: The potential of anticholinergics to provide bronchodilatory benefits over short-acting β 2-agonists (SABA) alone in patients with moderate-to-severe persistent asthma has not been well defined. Methods: An outpatient, randomized, double-blind, single-dose, crossover study in adult asthmatics with moderate-to-severe obstruction despite treatment with inhaled corticosteroids (ICS) was conducted comparing the fixed combination of ipratropium and albuterol (IB+ALB) to albuterol alone (ALB). Serial spirometry was performed over 6h. SABA were withheld for 8h, ICS and LABA for 24h. Results: A total of 113 patients were randomized, 106 completed the study (males n=47; mean±SD age=51±13 years). Mean±SD baseline FEV1=1.4±0.5 L (49±12% predicted). IB+ALB resulted in significantly greater improvements over ALB in the average improvement over baseline in FEV1 as approximated from the area under the curve from 0 to 6h after drug administration (72ml, p<0.01) and mean peak FEV1 response (55ml, p<0.01) as well as higher FEV1 responses at individual time points from 0.5 to 6h postdose (p<0.01 for all). Time to onset of response was similar between groups but time to peak and duration of response were longer with IB+ALB versus ALB (120 versus 60min and 245 versus 106min, respectively). Conclusion: IB+ALB resulted in significantly greater improvement in FEV1 and longer duration of response compared to ALB alone in patients with moderate-to-severe persistent asthma (Trial number: 1012.50; ClinicalTrial.gov NCT00096616). [Copyright &y& Elsevier]

The SAM domain of the Saccharomyces cerevisiae post-transcriptional regulator Vts1 has a high affinity towards RNA hairpins containing a CUGGC pentaloop. We present the 1.6Å X-ray crystal structure of the Vts1 SAM domain in its unliganded state, and the NMR solution structure of this domain in its RNA-bound state. Both structures reveal a canonical five helix SAM domain flanked by additional secondary structural elements at the N and C termini. The two structures are essentially identical, implying that no major structural rearrangements occur upon RNA binding. Amide chemical shift changes map the RNA-binding site to a shallow, basic patch at the junction of helix α5 and the loop connecting helices α1 and α2. [Copyright &y& Elsevier]

Commercial dry roasting of peanuts can result in accumulation of extensively heated peanut residue in ovens. These residues could pose a potential allergenic risk if residues are transferred to food products subsequently processed in the oven. Peanut residues can be detected in food products using antibody-based methods, but detection is greatly affected by thermal processing. We investigated the detectability of peanut allergens after excessive thermal processing using mass spectrometry (MS). Peanut kernel halves were roasted in a muffle furnace, ground, robustly extracted, and probed by immunoblot with sera from patients with peanut allergy (anti-peanut IgE) and anti-peanut IgG. Extracts were further analyzed by MS. After 8 h at 176 °C, detectable allergenic protein content, by MS, decreased 54.6-fold, with surviving contiguous regions sufficient to bind IgE to Ara h 3. Failure to detect peanut residues with antibody-based methods should not be regarded as an indication of the absence of peanut residues as robust extractions coupled with MS were able to identify peanut from some of these processed samples. Peanut residues should be physically removed prior to thermal processing as reliable existing antibody-based methods are inadequate to detect peanut residues after extensive heating of products. • Mass spectrometry analysis of peanut after heating. • Peanut allergens were detected after 8 h of roasting at 176 °C. • Observed IgE reactivity correlates with identified contiguous peptides. • Ovens should be cleaned to remove residues. [ABSTRACT FROM AUTHOR]