Mu Beta Research Articles

Mentoring for INnovative Design Solutions (MINDS): Key Design Considerations and Collaborative Teamwork across Universities for Clinical Translation

The main purpose of this paper is to share the Mentoring for INnovative Design Solutions (MINDS) Scholars Program developed by Alpha Eta Mu Beta, the International Biomedical Engineering Honor Society. The program’s goals are to (1) introduce biomedical engineering students to an open-ended design experience as part of interuniversity teams with industry and faculty mentors, and (2) develop the ability to create designs considering clinical translatability on teams with different backgrounds and areas of expertise. MINDS uses an experiential learning approach to (1) enrich student curricular experiences through inter-institutional collaboration, (2) build engineering design skills, including three key design considerations for clinical/commercial success: intellectual property protection, regulatory strategy, and market identification; and (3) emphasize the importance of end-user considerations. From 2015 to 2022, MINDS has involved 131 students from 50 universities and 22 faculty and industry mentors. Pre- and post-program surveys show statistically significant improvements in understanding of the design process, regulatory strategy, intellectual property protection, market definition, and key product requirements and features. Students also improved communication and teamwork skills. Many students indicated that MINDS participation made them more likely to choose careers that involve product development and/or entrepreneurship. Students attained a working ability to integrate market needs, regulatory strategy, and intellectual property considerations into the design process. They also further developed soft skills, such as conflict resolution, time management, and effective communication through the challenges of inter-institutional collaboration. Additionally, the program heightened their awareness of how biomedical devices and technologies can benefit society.

Behavioral Induction of a High Beta State in Sensorimotor Cortex Leads to Movement Slowing.

The sensorimotor beta rhythm (∼13-30 Hz) is commonly seen in relation to movement. It is important to understand its functional/behavioral significance in both health and disease. Sorting out competing theories of sensorimotor beta is hampered by a paucity of experimental protocols in humans that manipulate/induce beta oscillations and test their putative effects on concurrent behavior. Here, we developed a novel behavioral paradigm to generate beta and then test its functional relevance. In two human experiments with scalp EEG (n = 11 and 15), we show that a movement instruction generates a high beta state (postmovement beta rebound), which then slows down subsequent movements required during that state. We also show that this high initial beta rebound related to reduced mu-beta desynchronization for the subsequent movement and, further, that the temporal features of the beta state, that is, the beta bursts, related to the degree of slowing. These results suggest that increased sensorimotor beta in the postmovement period corresponds to an inhibitory state-insofar as it retards subsequent movement. By demonstrating a behavioral method by which people can proactively create a high beta state, our paradigm provides opportunities to test the effect of this state on sensations and affordances. It also suggests related experiments using motor imagery rather than actual movement, and this could later be clinically relevant, for example, in tic disorder.

Mu rhythm: State of the art with special focus on cerebral palsy.

Various specific early rehabilitation strategies are proposed to decrease functional disabilities in patients with cerebral palsy (CP). These strategies are thought to favour the mechanisms of brain plasticity that take place after brain injury. However, the level of evidence is low. Markers of brain plasticity would favour validation of these rehabilitation programs. In this paper, we consider the study of mu rhythm for this goal by describing the characteristics of mu rhythm in adults and children with typical development, then review the current literature on mu rhythm in CP. Mu rhythm is composed of brain oscillations recorded by electroencephalography (EEG) or magnetoencephalography (MEG) over the sensorimotor areas. The oscillations are characterized by their frequency, topography and modulation. Frequency ranges within the alpha band (∼10Hz, mu alpha) or beta band (∼20Hz, mu beta). Source location analyses suggest that mu alpha reflects somatosensory functions, whereas mu beta reflects motor functions. Event-related desynchronisation (ERD) followed by event-related (re-)synchronisation (ERS) of mu rhythm occur in association with a movement or somatosensory input. Even if the functional role of the different mu rhythm components remains incompletely understood, their maturational trajectory is well described. Increasing age from infancy to adolescence is associated with increasing ERD as well as increasing ERS. A few studies characterised mu rhythm in adolescents with spastic CP and showed atypical patterns of modulation in most of them. The most frequent findings in patients with unilateral CP are decreased ERD and decreased ERS over the central electrodes, but atypical topography may also be found. The patterns of modulations are more variable in bilateral CP. Data in infants and young children with CP are lacking and studies did not address the questions of intra-individual reliability of mu rhythm modulations in patients with CP nor their modification after motor learning. Better characterization of mu rhythm in CP, especially in infants and young children, is warranted before considering this rhythm as a potential neurophysiological marker of brain plasticity.

Classification of Motor Imagery EEG Based on Sparsification and Non-negative Matrix Factorization

The analysis of EEG is a hot topic in the area of biomedical signal processing. In this paper, the EEG signals with Mu (Μ) rhythm and Beta (Β) rhythm are used to solve the motor imagery problem, i.e., the imagery of the left hand and the right hand. The collected raw data is first filtered by FIR band-pass filter, followed by using the maximization of feature difference to increase the sparsity of the matrix. Then, to reduce the redundant information of these features, a non-negative matrix factorization (NMF) method is employed. Due to the usage of the NMF scheme, the obtained factorizations has been better class property. Simulations show that our method achieves higher classification accuracy (more than 91%) than existing results (about 86%).

Mu rhythm desynchronization by tongue thrust observation.

We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram (EEG) was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD) and event-related synchronization (ERS) for the mu rhythm (8–13 Hz) and beta (13−25 Hz) bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance.

Decreased Optical Nonlinearities upon CF3 Substitution on Tricyanofuran Acceptors

Replacement of the tricyanofuran (TCF) acceptor by its stronger analogue CF 3-TCF results in decreased second-order optical nonlinearities in merocyanines bearing a proaromatic 1,3-dithiole donor. The TCF-containing derivatives display exceptionally high mu beta values up to 31,000 x 10(-48) esu, unprecedented for 1,3-dithiole-based NLO-phores.

Uncertainty in exposure estimates made by modeling versus monitoring.

To conduct an initial exposure assessment for an airborne toxicant, industrial hygienists usually prefer air monitoring to mathematical modeling, even if only one exposure value is to be measured. This article argues that mathematical modeling may provide a more accurate (less uncertain) exposure estimate than monitoring if only a few air samples are to be collected, if anticipated exposure variability is high, and if information on exposure determinants is not too uncertain. To explore this idea, a hypothetical "true" distribution of 8-hour time-weighted average airborne exposure values, C, is posited based on an NF exposure model. The C distribution is approximately lognormal. Estimation of the mean value, microC (the long-term average exposure level), is considered. Based on simple random sampling of workdays and use of the sample mean C to estimate microC, accuracy (uncertainty) in the estimate is measured by the mean square error, MSE(C). In the alternative, a modeling estimate can be made using estimates of the mean chemical emission rate microG, the mean room dilution supply air rate microQ, and the mean dilution ventilation rate in the NF of the source mu beta. By positing uniform distributions for the estimates microG, microQ, and mu beta, an equation for the modeling mean square error MSE(microC) is presented. It is shown that for a sample size of three or fewer workdays, mathematical modeling rather than air monitoring should provide a more accurate estimate of microC if the anticipated geometric standard deviation for the C distribution exceeds 2.3.

Design and synthesis of push-pull chromophores for second-order nonlinear optics derived from rigidified thiophene-based pi-conjugating spacers.

Two series of push-pull chromophores built around thiophene-based pi-conjugating spacers rigidified either by covalent bonds or by noncovalent intramolecular interactions have been synthesized and characterized by UV-vis spectroscopy, electric field induced second harmonic generation (EFISH) and differential scanning calorimetry. Comparison of the linear and second-order nonlinear optical properties of chromophores based on a covalently bridged dithienylethylene (DTE) spacer with those of their analogues based on open chain DTE shows that the rigidification of the spacer produces a considerable bathochromic shift of the absorption maximum together with a dramatic enhancement of the molecular quadratic hyperpolarizability (mu beta) which reaches values among the highest reported so far. A second series of NLO-phores has been derived from a 2,2'-bi(3,4-ethylenedioxythiophene) (BEDOT) pi-conjugating spacer. As indicated by X-ray and UV-vis data, rigidification of the spacer originates in that case, from noncovalent intramolecular interactions between sulfur and oxygen atoms. Again, comparison with the parent compounds based on an unsubstituted bithiophene spacer reveals a marked red shift of the absorption maximum and a large enhancement of mu beta. In an attempt to distinguish the contribution of the electronic and geometrical effects of the ethylenedioxy group, a third series of NLO-phores based on 3,4-ethylenedioxythiophene (EDOT) and 3,4-dihexyloxythiophene spacers has been synthesized. Comparison with compounds based on unsubstituted thiophene shows that, despite a red shift of lambda(max), introduction of alkoxy groups leads to a decrease of mu beta. Theoretical calculations indicate that this effect results from a decrease of the dipole moment (mu) caused by the auxiliary electron-donor alkoxy groups on the thiophene ring. In contrast, replacement of BT by BEDOT produces an increase of mu, which associated with the noncovalent rigidification of the BT system accounts for the observed enhancement of mu beta.

A Constitutively Activated Chimeric Cytokine Receptor Confers Factor-Independent Growth in Hematopoietic Cell Lines

The high-affinity receptor for granulocyte-macrophage colony-stimulating factor (GMR) comprises at least 2 distinct subunits, alpha and beta common (beta c), whereas the normal erythropoietin receptor (nEpoR) comprises only one known subunit. An arginine to cysteine (R129C) mutation of the extracytoplasmic domain of the murine EpoR leads to Epo-independent growth in transduced cells (cEpoR). To investigate the proliferative functions of the cytoplasmic regions of each GMR subunit separately and the potential of the R129C EpoR mutation to induce factor-independent growth through heterologous receptor regions, we constructed four hybrid receptors: the extracellular region of either murine nEpoR or cEpoR linked to the transmembrane and cytoplasmic regions of either the human GMR alpha or beta c subunit (nE alpha, nE beta, cE alpha, and cE beta). We then expressed them in an interleukin-3-dependent murine cell line, Ba/F3. Expression of nE beta led to Epo-dependent growth, whereas expression of cE beta conferred factor-independent growth. Surprisingly, expression of cE alpha also resulted in factor-independent cell growth, whereas nE alpha did not respond to Epo. Furthermore, the functional hybrid receptors showed Epo-dependent (nE beta) or constitutive (cE alpha and cE beta) tyrosine phosphorylation of the cytoplasmic kinases JAK1 and JAK2. We reasoned that the proliferative signal of cE alpha was transduced either through the alpha tail itself or through an accessory protein such as the endogenous murine beta common subunit (mu beta c). To distinguish these possibilities, the chimeric receptor cE alpha was expressed in the interleukin-2-dependent murine cell line, CTLL-2, that does not express mu beta c. cE alpha did not induce cell growth in CTLL-2; however, when mu beta c was coexpressed with cE alpha in CTLL-2, factor-independent growth was reconstituted. In conclusion, the cytoplasmic domain of the GMR alpha subunit requires a beta chain for transduction of a proliferative signal. Furthermore, the R129C EpoR mutation can constitutively activate heterologous receptors to mediate factor-independent proliferation.

Electro-optics in thermopoled polymer films

Measurements of the electrooptic (EO) properties of polar polymetric films are presented. The polar order is induced by thermopoling using fixed contacts. In doped films, high doping concentrations (20% wt.) have been achieved of the nonlinear organic molecule 2-(N,N-dimethylamino)-5-nitroacetanilide, DAN. The EO coefficients obtained include a contribution from the host polymer in the case of a polycarbonate host where films have EO coefficients higher than those of comparably doped PMMA materials. Among 'side-chain' polymers the authors found that poly(4-vinylpyridine), P-4VP, obtained commercially, also can be poled efficiently and yields moderate EO coefficients. An experimental value for the microscopic nonlinear figure of merit mu beta in P-4VP is calculated and compared with a theoretical value. The resulting mismatch reveals that the simplified thermodynamic model may be inappropriate for this side chain polymer and that low-frequency contributions to the nonlinearity may be significant. >

G inversion in bacteriophage Mu DNA is stimulated by a site within the invertase gene and a host factor

The Gin function of bacteriophage Mu catalyzes inversion of the G DNA segment, thus switching the host range of Mu phage particles. This site-specific recombination event takes place between inverted repeat sequences (IR) that border the G segment. Sequences in the Mu beta region extending approximately from position 118 to 178 are essential for efficient inversion. In cis this region, termed sis, stimulates inversion about 15-fold. Neither the relative orientation of sis with respect to the IR sequences nor the distance to IR substantially influences the stimulatory effect. For full activity purified Gin protein must be supplemented with crude host factor from E. coli K12. We suggest that, in addition to Gin, a DNA-binding host protein is required for efficient G inversion.

Stability and magnetism of hydrides of nonstoichiometric ZrMn2

The hydrides of ZrMn/sub 2+x/, with x = 0.6, 0.8, and 1.8, have been prepared and studied. Hydrogen vapor pressure rises rapidly as x increases, increasing more than 50-fold for ZrMn/sub 3/ /sub 8/-H compared to the ZrMn/sub 2/-H system. Capacity of the systems for hydrogen is large; the hydrogen densities relative to that of liquid hydrogen range from 0.95 to 1.48. Kinetics of exchange of hydrogen between the hydride and gaseous hydrogen is very rapid; uptake of hydrogen is 90% complete within 1 min. This appears to be a consequence of the thinness of the oxide coating and the high concentration of Mn in the surface, as determined by Auger spectroscopy. Magnetic measurements show that hydrogenation transforms the paramagnetic host metal into a ferromagnetic material. The ordered moments range from 0.04 to 0.18 ..mu beta.. er formula unit of (Zr, Mn)Mn/sub 2/-H, increasing wth increase in the stoichiometric excess of Mn. The ordered moments are ascribed to this excess Mn and are approx. 0.5 ..mu beta../(Mn atom). The system seems to consist of regions in which ferromagnetic interactions prevail interspersed with those in which antiferromagnetic interactions predominate. ..delta..H and ..delta..S for the evolution of hydrogen are unusually small formore » systems of this nature. This is presumably a consequence of the strong influence of hydrogen on the magnetic nature of the system. The low values of ..delta..H are very significant in regard to practical applications of these materials for hydrogen storage.« less

Magnetic, crystallographic, and hydrogen-storage characteristics of Zr1-xTixMn2 hydrides

The (Zr,Ti)Mn/sub 2/ ternary alloys hydride to H/Zr/sub 1-x/Ti/sub x/Mn/sub 2/ compositions ranging from 3.6 for x = 0 to 1.6 for x = 0.5. Pressure-composition isotherms are presented for several temperatures. The shape of the isotherms suggests that a second phase, a hydride phase, exists at higher hydrogen concentrations. Hydrogen absorption and desorption occurs very rapidly. The processes are 90% complete in 1 and 5 min for absorption and desorption, respectively. The rapidity of these processes appears to be a consequence of only a thin layer of oxidation. The nonhydrides of all of the Zr/sub 1-x/Ti/sub x/Mn/sub 2/ systems show weak Pauli paramagnetism. On the other hand, the hydrides of ZrMn/sub 2/ and Zr/sub 1-x/Ti/sub x/Mn/sub 2/ with x = 0.3 and 0.4 exhibit ferromagnetism with Curie temperature ranging from 143 to 185 K and with moments ranging from 0.04 to 0.42 ..mu beta../(formula unit). The hydride of Zr/sub 0/ /sub 9/Ti/sub 0/ /sub 1/Mn/sub 2/ exhibits only enhanced paramagnetism. The Zr/sub 0/ /sub 8/Ti/sub 0/ /sub 2/Mn/sub 2/ hydride shows spin-glass behavior as a result of the occurrence of ferromagnetic clusters in a paramagnetic matrix. These complex and varied magnetic behaviors are attributed to the effects of (1)more » variations in the Mn-Mn spacing (and/or the electron concentrations in the 3d bands) and (2) varying local hydrogen concentrations occurring as a result of statistical fluctuations.« less

Reduction of a particle transfer problem in finite plane-parallel media to a problem of semi-infinite media. II

For pt.I see ibid., vol.13, p.1811, 1980. A recently developed method, which reduces a particle transfer problem in finite plane-parallel media to a problem of a semi-infinite media by means of invariant embedding is used to find the reflection and transmission functions of the finite medium, assuming that the surface of the medium is subjected to an angular flux of the type psi (0, mu )= mu beta mu >0 beta =0,1,2, ... Calculations for the semi-infinite slab show that the Eddington approximation (the diffusion-type model) used here is adequately accurate for thick slabs. When applied to finite slabs with beta =0, the accuracy is within 1% for slabs thicker than one mean free path. When applied for beta >0, accuracy of better than 1% is achieved in slabs of only one mean free path. The same approach is applied to a synthetic kernel approximating the two-term Henyey-Greenstein phase function. The modelled scattering law allows a combination of forward scattering, back scattering and linearly anisotropic scattering.

Electrical resistivity of dislocations in metals

The transport equation for electrons in a dislocated crystal is solved in a way which allows explicitly for a complex (many sheets, open or closed) Fermi surface. Assuming resonance scattering of Fermi electrons by the dislocation core, and assuming negligible interband scattering the author obtains simple expressions for dislocation limited resistivity in metals of arbitrary bandstructure. The dislocation limited mobility mu of electrons or holes in metals of arbitrary bandstructure and containing randomly oriented dislocations of density beta (length per unit volume) is given by the universal expression mu beta =3e/8h(cross)=5.70*1014 V-1 s-1. Experimental data on dislocation resistivity for seventeen metals from ten subgroups of the periodic table are reviewed and comparison is made with calculated values. Good overall agreement of theory with experiment, encompassing a range from 10-19 to 10-14 Omega cm3 of dislocation specific resistivity, provides strong evidence both for the existence of dislocation resonances and, for multiband metals, the minor importance of interband scattering by the dislocation core.

The use of computer analysis for diagnosis in routine electroencephalography.

1. Frequency power spectra and mutual coherence functions of 8 stimulatenously recorded E.E.G. derivations have been computed in approximately 500 non-specially selected patients referred to the department for E.E.G. recording. 2. On basis of the data obtained some provisionnal conclusions have been drawn, the most important of those being that the analyses contribute significantly and in some cases essentially to the understanding of the E.E.G. and therefore should be carried out in all E.E.Gs recorded to our department. 3. It has been observed that mu rhythms and beta rhythms appear to be essentially different from alpha rhythms by exhibiting no bilateral coherence whereas alpha rhythms almost invariably are considerably bilateral coherent.

Neutrino Processes and Pair Formation in Massive Stars and Supernovae.

Abstract : The paper traces the physical properties of matter inside highly evolved stars, on the assumption that the whole material of the star is non-degenerate and that the star is in quasi-hydrostatic equilibrium. When these conditions are satisfied, the physical evolution of a particular element of material is insensitive to the stallar model but not to the total mass of the star. Our considerations refer explicity to stars of mass greater than approx. 10 micro sun but less than 1,000,000 micro sun, at which point general relativistic considerations become paramount. In Parts I and II neutrino-loss processes and neutrino-loss rates are examined. In Part III a method is developed for calculating the product mu beta as a function of temperature when electron positron pair formation is taken into account. In this product mu is the mean molecular weight and beta the ratio of gas pressure to gas plus radiation pressure. In Part IV the internal energy of matter is considered again as a function of temperature, and including the effects of pair formation. Parts V, VI, and VII are concerned with nuclear reactions, in particular with oxygen burning, the alpha-process, and the e-process. In the final Parts VIII and IX the onset of a supernova of Type II is considered in which the central core implodes while the mantle and envelope of the star explode. These considerations are tentative because the discussion now involves the structure of the whole star, and hence of the stellar model. It is emphasized that massive stard do not necessarily become Type II supernovae but can collapse to general relativistic singularities.

A Polarized-Neutron Investigation of the MnNi3 Alloy

Polarized neutrons were used to determine the magnetic moments of the MnNi3 alloy. The ratio of the magnetic to the nuclear scattering amplitude was determined from the polarization ratio for a given reflection. The magnetic moments of Mn and Ni were calculated by using the magnetic form factors of metallic Ni and the Mn2+ ion. The average magnetic moment per atom was found to be approx equal l mu BETA, in agreement with experimental results.