Elastic Vector Solitons in Soft Architected Materials.

We demonstrate experimentally, numerically, and analytically that soft architected materials can support the propagation of elastic vector solitons. More specifically, we focus on structures comprising a network of squares connected by thin and highly deformable ligaments and investigate the propagation of planar nonlinear elastic waves. We find that for sufficiently large amplitudes two components-one translational and one rotational-are coupled together and copropagate without dispersion. Our results not only show that soft architected materials offer a new and rich platform to study the propagation of nonlinear waves, but also open avenues for the design of a new generation of smart systems that take advantage of nonlinearities to control and manipulate the propagation of large amplitude vibrations.

Middle mesial canals in mandibular molars: incidence and related factors.

INTRODUCTION: Although the internal anatomy of mandibular molars has been extensively studied, information about middle mesial (MM) canals is limited. The primary aim of this retrospective study was to evaluate the incidence of MM canals in mandibular first and second molars. The secondary aim was to correlate the incidence of MM canals with variables of molar type, sex, age, ethnicity, and presence of a second distal canal. METHODS: All mature permanent first and second mandibular molars treated from August 2012 to May 2014 were included in the analysis. After completion of root canal instrumentation in all main canals, the clinician inspected the isthmus area of the mesial root using the dental operating microscope. If there was a catch point in this area with a file or explorer, the operator spent more time attempting to negotiate an MM canal. RESULTS: Seventy-five mandibular first and second molars were treated during the specified period. Fifteen (20%) teeth had negotiable MM canals. The incidence of MM canals was 32.1% in patients ≤ 20 years old, 23.8% in patients 21-40 years old, and 3.8% in patients > 40 years. Analysis of data revealed a significant difference in the distribution of MM canals among different age groups (P < .05). The differences in the distribution of MM canals based on sex, ethnicity, molar type, and presence of a second distal canal were not significant. CONCLUSIONS: The incidence of negotiable MM canals overall and their frequency of identification in younger patients were higher than in previous reports.

Rate-independent dissipation and loading direction effects in compressed carbon nanotube arrays.

Arrays of nominally-aligned carbon nanotubes (CNTs) under compression deform locally via buckling, exhibit a foam-like, dissipative response, and can often recover most of their original height. We synthesize millimeter-scale CNT arrays and report the results of compression experiments at different strain rates, from 10(-4) to 10(-1) s(-1), and for multiple compressive cycles to different strains. We observe that the stress-strain response proceeds independently of the strain rate for all tests, but that it is highly dependent on loading history. Additionally, we examine the effect of loading direction on the mechanical response of the system. The mechanical behavior is modeled using a multiscale series of bistable springs. This model captures the rate independence of the constitutive response, the local deformation, and the history-dependent effects. We develop here a macroscopic formulation of the model to represent a continuum limit of the mesoscale elements developed previously. Utilizing the model and our experimental observations we discuss various possible physical mechanisms contributing to the system's dissipative response.

Effect of density variation and non-covalent functionalization on the compressive behavior of carbon nanotube arrays.

Arrays of aligned carbon nanotubes (CNTs) have been proposed for different applications, including electrochemical energy storage and shock-absorbing materials. Understanding their mechanical response, in relation to their structural characteristics, is important for tailoring the synthesis method to the different operational conditions of the material. In this paper, we grow vertically aligned CNT arrays using a thermal chemical vapor deposition system, and we study the effects of precursor flow on the structural and mechanical properties of the CNT arrays. We show that the CNT growth process is inhomogeneous along the direction of the precursor flow, resulting in varying bulk density at different points on the growth substrate. We also study the effects of non-covalent functionalization of the CNTs after growth, using surfactant and nanoparticles, to vary the effective bulk density and structural arrangement of the arrays. We find that the stiffness and peak stress of the materials increase approximately linearly with increasing bulk density.

Molecular markers for seed colour in Brassica juncea.

A detailed RFLP map was used to map QTLs associated with seed colour in Brassica juncea using a doubled-haploid population derived from a cross between a black/brown-seeded cultivar and a yellow-seeded breeding line. Segregation analysis suggested that seed colour was under control of 2 unlinked loci with duplicate gene action. However, QTL analysis revealed 3 QTLs, SC-B4, SC-A10 and SC-A6, affecting seed colour. The QTLs were consistent across environments, and individually explained 43%, 31%, and 16%, respectively, and collectively 62% of the phenotypic variation in the population. Digenic interaction analysis showed that closest flanking locus of QTL SC-B4, wg7b6cNM, had strong epistasis with the locus wg5a1a, which is tightly linked to QTL SC-A6. The interaction of these 2 loci explained 27% of the phenotypic variation in the population, while the whole model explained 84%. In a multiple regression model, the effects of QTL SC-A10, as well as its interaction with other loci, were non-significant, whereas the effects of loci wg7b6cNM and wg5a1a and their interaction were significant. Ninety-eight percent of the DH lines carried the expected alleles of loci wg7b6cNM and wg5a1a for seed colour, confirming that only these 2 loci were linked to seed colour in B. juncea. Four additional digenic interactions significantly affected seed colour, and all 5 digenic interactions were consistent across environments.

Oxidative metabolism of murine macrophages.

This unit describes two simple and straightforward microassays that can be used to measure the levels of NO(2)(-) and O(2)(-), respectively that are generated by a small number of immunologically-stimulated macrophages. Detection of these products may be used to identify cytokine(s), microbe(s), or microbial products(s) that regulate oxidative metabolism and effector activity. Although a number of other reliable and sensitive methods are available for assaying these two oxidative metabolites, the microassays described here require little time, technical expertise, or materials. It is not clear at present whether human monocytes/macrophages can also produce NO(2)(-). These protocols are therefore restricted to mouse macrophages.

Delayed cardiac tamponade following a stab wound: a case report.

Penetrating trauma is a frequent presentation to urban emergency departments (EDs). Pericardial effusion with cardiac tamponade is a possible complication of penetrating trauma to the chest, to the back, and to the upper abdomen. Even if patients are stable initially without signs or symptoms of cardiac tamponade, there can be delayed sequelae. Presented is a case of cardiac tamponade diagnosed 21 days after a stab wound to the epigastrium.

Interaction of anti-cholesterol antibodies with human lipoproteins.

Inoculation of mice with cholesterol-rich liposomes containing the adjuvant monophosphoryl lipid A results in the production of antiserum containing IgM Ab to cholesterol. The specificity of the Ab was to cholesterol and structurally similar sterols containing a 3 beta-hydroxyl group. Anti-cholesterol binding activity was significantly diminished if the 3 beta-hydroxyl was altered by either epimerization, substitution, oxidation, or esterification. A similar specificity for 3 beta-hydroxy-sterols was observed for an anti-cholesterol IgM mAb. Both hyperimmune serum and the mAb reacted with intact human very-low-/intermediate-density lipoprotein (VLDL/IDL) and low-density lipoproteins (LDL), but not high-density lipoproteins (HDL), in an ELISA, but could react with total lipid extracts containing cholesterol that were prepared from all three lipoprotein classes. Functionally, immune serum or the mAb aggregated and induced a fusion-like reaction with VLDL/IDL and LDL at low temperatures: these aggregates result in spherical structures visible with light microscopy. Similarly, binding of anti-cholesterol A to small cholesterol-rich liposomes resulted in the appearance of vesicular structures with approximately 20- to 200-fold increased diameters. These data demonstrate that the anti-cholesterol Ab recognize unesterified cholesterol in VLDL/IDL and LDL; high-density lipoprotein cholesterol in the intact lipoprotein, however, appears to be protected from reaction with these Ab.

Analysis of anticholesterol antibodies using hydrophobic membranes.

An analytical immunoblotting procedure and a serological enzyme-linked immunosorbent assay (ELISA) for the characterization of antibodies to cholesterol are described. Hydrophobic membranes consisting of polyvinylidene fluoride (PVDF) are used to immobilize cholesterol for immunodetection by anti-sterol antibodies. To determine whether antibodies to cholesterol were induced after immunization with liposomal cholesterol, we separated total lipid extracts of very-low density lipoproteins by thin layer chromatography (TLC) on silica gel plates and transferred the separated lipid classes to PVDF membranes using isopropanol to facilitate passive diffusion. Lipid transfer was confirmed by exposure of membranes to iodine vapors or by staining of cholesterol with filipin complex. Serum from immunized mice reacted with cholesterol, whereas pre-immune serum or serum from mice injected with control liposomes did not bind. To determine the amount of anti-cholesterol activity in serum, we coated microtiter plates consisting of PVDF membrane wells with cholesterol. The PVDF membrane-based ELISA was found to be more reproducible and four-fold more sensitive than the conventional ELISA on polystyrene plates. These techniques may be useful in the analysis of anti-sterol antibodies and antibodies to other hydrophobic antigens.

CEO summit. The new delivery & financing realities. Part II of III.

In cooperation with McManis Associates Inc., Hospitals & Health Networks recently convened a summit on the integration of financing and delivery in health care. This is the second of a three-part series on lessons learned by those on the front lines of integration activity. The session was designed and facilitated by senior associates at McManis. Among the issues discussed in this second segment. What level of understanding do purchasers have of quality differentiators in health care services? Can provider-driven integrated delivery systems compete with insurer-driven ones? And what happens when, as in the Philadelphia market, a large integrated delivery system merges with a dominant insurer? Can that model be replicated in other markets?

CEO summit. The new delivery & financing realities. Part III of III.

In cooperation with McManis Associates Inc., Washington, Hospitals & Health Networks recently convened a summit on the integration of financing and delivery in health care. This installment is the third of a three-part series on lessons learned by those on the front lines of integration activity. The session was designed and facilitated by senior associates at McManis. Among the issues summit participants discussed in the second segment: What level of understanding do purchasers have of the factors that differentiate quality in health care services? Can provider-driven integrated delivery systems compete with insurer-driven ones? And what happens when a large integrated delivery system merges with a dominant insurer, as happened in the Philadelphia market? Can that model be successfully replicated in other markets? In this final segment, participants talk about whether providers' deep connections to their communities will add value in a reformed delivery system; how incentives might be aligned among all the players in integrated networks and organizations; how the concept of community focus might be redefined under systems integration; and the process involved in preparing for constant, accelerated change. The second segment concluded with comments about the assets providers and insurers bring to integrated health systems, and whether the merger experience of Graduate Health System and QCC/Independence Blue Cross could be replicated in other markets or not.

CEO summit. The new delivery & financing realities. Part I of III.

In cooperation with McManis Associates Inc., Hospitals & Health Networks recently convened a summit on the integration of financing and delivery of health care. This report is the first of a three-part series on lessons learned by those on the front lines of integration activity. The session was designed and facilitated by senior associates at McManis. Among the issues discussed in this first segment: Is integration necessary to satisfy the demands of health care payers? Is integration the way to cost-containment? How can costs be squeezed out of the system? What relationship will physicians have to hospitals and insurers in integrated systems?

Induction of nitric oxide synthase protects against malaria in mice exposed to irradiated Plasmodium berghei infected mosquitoes: involvement of interferon gamma and CD8+ T cells.

Exposure of BALB/c mice to mosquitoes infected with irradiated Plasmodium berghei confers protective immunity against subsequent sporozoite challenge. Immunized mice challenged with viable sporozoites develop parasitemia when treated orally with substrate inhibitors of nitric oxide synthase (NOS). This suggests that the production of nitric oxide (NO) prevents the development of exoerythrocytic stages of malaria in liver. Liver tissue from immunized mice expressed maximal levels of mRNA for inducible NOS (iNOS) between 12 and 24 h after challenge with sporozoites. Intraperitoneal injection of neutralizing monoclonal antibody against interferon gamma (IFN-gamma) or in vivo depletion of CD8+ T cells, but not CD4+ T cells, at the time of challenge blocked expression of iNOS mRNA and ablated protection in immunized mice. These results show that both CD8+ T cells and IFN-gamma are important components in the regulation of iNOS in liver which contributes to the protective response of mice immunized with irradiated malaria sporozoites. IFN-gamma, likely provided by malaria-specific CD8+ T cells, induces liver cells, hepatocytes and/or Kupffer cells, to produce NO for the destruction of infected hepatocytes or the parasite within these cells.

The structural identification of a methyl analog of methaqualone via 2-dimensional NMR techniques.

A submission to the Drug Enforcement Administration North Central Laboratory of a substance believed to be a structural analog of methaqualone hydrochloride precipitated an interest in being able to obtain a rapid and positive identification of such compounds. Both mass spectrometry and proton NMR spectroscopy (1-dimensional) provided evidence to suggest that the structural analog possessed a second methyl group in the molecule, relative to methaqualone, and that the methyl group was attached to the existing methyl-substituted phenyl ring. By application of proton 2-dimensional (2-D) NMR techniques, specifically the homonuclear shift correlation spectroscopy (COSY) and 2-D NOE (NOESY), the precise location of the methyl group in this unknown methaqualone analog was established and shown to have the structure 2.

Detection of silent temporal gaps between narrow-band noise makers having second-formantlike properties of voiceless stop/vowel combinations.

Temporal gap detection thresholds were measured in narrow-band noise-burst markers having acoustic characteristics representative of isolated steady-state second-formant (F2) properties for/p,t,k/paired separately with/i,ae,u,o/. The results revealed that gap detection threshold increased systematically as the difference was increased between the simulated stop and vowel F2 frequencies. A strong positive correlation (r = 0.87) between gap detection threshold and linear marker center frequency difference was highly significant (p < 0.001). Differences in other stimulus features had little influence on gap detection performance. Implications for speech perception are discussed.

The role of frequency selectivity in measures of auditory and vibrotactile temporal resolution.

The purpose of this study was to compare the role of frequency selectivity in measures of auditory and vibrotactile temporal resolution. In the first experiment, temporal modulation transfer functions for a sinusoidally amplitude modulated (SAM) 250-Hz carrier revealed auditory modulation thresholds significantly lower than corresponding vibrotactile modulation thresholds at SAM frequencies greater than or equal to 100 Hz. In the second experiment, auditory and vibrotactile gap detection thresholds were measured by presenting silent gaps bounded by markers of the same or different frequency. The marker frequency F1 = 250 Hz preceded the silent gap and marker frequencies after the silent gap included F2 = 250, 255, 263, 310, and 325 Hz. Auditory gap detection thresholds were lower than corresponding vibrotactile thresholds for F2 markers less than or equal to 263 Hz, but were greater than the corresponding vibrotactile gap detection thresholds for F2 markers greater than or equal to 310 Hz. When the auditory gap detection thresholds were transformed into filter attenuation values, the results were modeled well by a constant-percentage (10%) bandwidth filter centered on F1. The vibrotactile gap detection thresholds, however, were independent of marker frequency separation. In a third experiment, auditory and vibrotactile rate difference limens (RDLs) were measured for a 250-Hz carrier at SAM rates less than or equal to 100 Hz. Auditory RDLs were lower than corresponding vibrotactile RDLs for standard rates greater than 10 Hz. Combination tones may have confounded auditory performance for standard rates of 80 and 100 Hz. The results from these experiments revealed that frequency selectivity influences auditory measures of temporal resolution, but there was no evidence of frequency selectivity affecting vibrotactile temporal resolution.

Signal uncertainty and psychometric functions in profile analysis.

Experiment 1 was conducted to compare the effects of signal frequency uncertainty on the detection of a change in spectral shape and on the detection of a tone in wideband noise. Results indicate that for both tasks the uncertainty effect was small, being on average about 3 dB. In a second experiment, psychometric functions were measured for the detection of changes in the spectral shape of multicomponent complexes. Psychometric functions for profile tasks have a 25-dB range and are similar to those measured for the detection of an increment in the level of a single sinusoid. These psychometric functions are different from those found when detecting a signal in noise, which typically have a 10-dB range. Three equations for the shape of the psychometric functions were compared. The difference in the resulting fits was small, thus preventing an unambiguous choice of functional form.

The use of an Ommaya reservoir for administration of morphine sulphate to control pain in select cancer patients.

The Ommaya reservoir is an implantable device which allows percutaneous intraventricular administration of preservative-free morphine sulfate. Use of this device in select cancer patients has worked well in providing pain control when conventional methods have failed. Using an Ommaya reservoir is not without complications, and patients may experience side effects of morphine, but most of these effects can be controlled. Teaching begins early so the patient can be discharged with a dose and schedule which provide pain control, and the responsible family member can be proficient in administration. Home care and follow-up are necessary to assure pain control and absence of complications.