Giant cell reparative granuloma of the petrous temporal bone: a case report and literature review

Giant cell reparative granuloma (GCRG) is an unusual, benign bone lesion that most commonly affects the maxilla and mandible; skull involvement is rare. The etiology is uncertain but may be related to trauma. GCRG is difficult to distinguish from giant cell tumor of the bone and has a lower recurrence rate. Thirteen reports of temporal bone GCRG in 11 patients have been reported. One report of a petrous GCRG in a 3-year-old girl has been identified. A 38-year-old male presented with a 2-year history of fullness in his left ear, ipsilateral hearing loss, and intermittent cacosmia. Computed tomography and magnetic resonance imaging revealed a large left-sided anterior temporal extradural mass. The patient underwent a left frontotemporal craniotomy and resection of a left temporal fossa tumor that involved the petrous and squamous parts of the temporal bone. The patient's post-operative course was uneventful, except for increased hearing loss secondary to opening of the epitympanum. Follow-up at one month revealed no other problems. Histopathology of the specimen was consistent with a giant cell reparative granuloma.

The evolutionary pathway from anoxygenic to oxygenic photosynthesis examined by comparison of the properties of photosystem II and bacterial reaction centers

In photosynthetic organisms, such as purple bacteria, cyanobacteria, and plants, light is captured and converted into energy to create energy-rich compounds. The primary process of energy conversion involves the transfer of electrons from an excited donor molecule to a series of electron acceptors in pigment-protein complexes. Two of these complexes, the bacterial reaction center and photosystem II, are evolutionarily related and structurally similar. However, only photosystem II is capable of performing the unique reaction of water oxidation. An understanding of the evolutionary process that lead to the development of oxygenic photosynthesis can be found by comparison of these two complexes. In this review, we summarize how insight is being gained by examination of the differences in critical functional properties of these complexes and by experimental efforts to alter pigment-protein interactions of the bacterial reaction center in order to enable it to perform reactions, such as amino acid and metal oxidation, observable in photosystem II.

Second-harmonic generation in a bent-core nematic liquid crystal

Second-harmonic generation (SHG) is studied in the magnetically aligned nematic phase of a bent-core liquid crystal (BCN) and compared to similar measurements made on a conventional rodlike (calamitic) nematic compound. The second-harmonic (SH) light detected from both materials is predominantly due to scattering and therefore incoherent. Results on the calamitic are consistent with a polarization induced by ordinary director fluctuations in the nematic phase. However, the SH scattering collected in the BCN exhibits a different temperature and angular dependence. We discuss how these differences could arise from the effects of short-range correlated, smectic-C-type molecular clusters, which have been detected in recent studies on various BCN materials.

First measurement of Bose-Einstein correlations in proton-proton collisions at √s=0.9 and 2.36 TeV at the LHC

Bose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed in the form of an enhancement of pairs of same-sign charged particles with small relative four-momentum. The size of the correlated particle emission region is seen to increase significantly with the particle multiplicity of the event.

Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at square root of s = 7 TeV

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at square root of s = 7  TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/dη|(|η|<0.5) = 5.78 ± 0.01(stat) ± 0.23(syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from square root of s = 0.9 to 7 TeV is [66.1 ± 1.0(stat) ± 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 ± 0.005(stat) ± 0.015(syst)  GeV/c. The results are compared with similar measurements at lower energies.

Primary structure of the M subunit of the reaction center from Rhodopseudomonas sphaeroides

The reaction center is a membrane-bound bacteriochlorophyll-protein complex that mediates the primary photochemical events in the photosynthetic bacterium Rhodopseudomonas sphaeroides. The previously determined amino-terminal sequences of the three subunits of the reaction center protein were used to design synthetic mixed oligonucleotide probes for the structural genes encoding the subunits. One of these probes was used to isolate and clone a fragment of DNA from R. sphaeroides that contained the gene encoding the M subunit. The nucleotide sequence of this gene was determined by the dideoxy method. In addition, a number of tryptic and chymotryptic peptides from the M protein were isolated and subjected to sequence analysis, and the sequence of the carboxyl terminus was determined. Together with the amino-terminal sequence, the data establish the primary structure of the M protein. The distribution of hydrophobic residues in the amino acid sequence suggests the presence of five membrane-spanning segments. A significant homology was found between the amino acid sequence of the M subunit and a thylakoid membrane protein (M(r) 32,000) from spinach that has been implicated in herbicide and quinone binding.

Biomechanical comparison of techniques to reduce the bulk of lacerated flexor tendon ends within digital sheaths of the porcine forelimb

PURPOSE

Zone II flexor tendon repairs may create a bulging effect with increased bulk and resistance to tendon gliding. A biomechanical time 0 study was performed to assess 2 methods of tendon antibulking for work of flexion and strength characteristics.

METHODS

We placed 24 fresh-frozen porcine forelimb tendons in a custom jig. Deep flexor tendon was sectioned just distal to the intact A1 and A2 pulleys. Specimens were divided into 3 groups before repair: group 1, nonmodified tendon; group 2, 30 degrees bilateral notch excised from both tendon ends; and group 3, triangular longitudinal central wedge excised from both tendon ends. All repairs used a 4-strand modified Kessler core suture and running circumferential epitendinous suture. Work of flexion, 2-mm gap formation, and ultimate load to failure were tested.

RESULTS

Both antibulking techniques (groups 2 and 3) had significantly less work of flexion than group 1 (36.3 and 34.9 J vs 142.9 J, p < .001). There was no significant change in work of flexion between groups 2 and 3 (p > .05). There was no significant difference in terms of 2-mm gap formation among the 3 groups (p > .05). Groups 1 and 3 exhibited a significantly higher load to failure compared with group 2 (p < .05).

CONCLUSIONS

The antibulking repair techniques used in this study decrease the work of flexion with no significant change in force to 2-mm gap formation. Group 2, however, did have significantly lower load to failure. These techniques might be beneficial in zone II flexor tendon injury, in which the tight annular pulley system restricts tendon gliding. However, this is a time 0 study and the potential adverse effects of increase tendon manipulation and trauma were not analyzed, which might increase adhesions and scar during the healing phase of tendon repair.

Evaluation of a modified Fitts law brain-computer interface target acquisition task in able and motor disabled individuals

A brain-computer interface (BCI) is a communication system that takes recorded brain signals and translates them into real-time actions, in this case movement of a cursor on a computer screen. This work applied Fitts' law to the evaluation of performance on a target acquisition task during sensorimotor rhythm-based BCI training. Fitts' law, which has been used as a predictor of movement time in studies of human movement, was used here to determine the information transfer rate, which was based on target acquisition time and target difficulty. The information transfer rate was used to make comparisons between control modalities and subject groups on the same task. Data were analyzed from eight able-bodied and five motor disabled participants who wore an electrode cap that recorded and translated their electroencephalogram (EEG) signals into computer cursor movements. Direct comparisons were made between able-bodied and disabled subjects, and between EEG and joystick cursor control in able-bodied subjects. Fitts' law aptly described the relationship between movement time and index of difficulty for each task movement direction when evaluated separately and averaged together. This study showed that Fitts' law can be successfully applied to computer cursor movement controlled by neural signals.

The receptor tyrosine kinase MerTK regulates dendritic cell production of BAFF

The MerTK receptor tyrosine kinase is an important negative regulator of dendritic cell function and is required to prevent B cell autoimmunity in vivo. It is not currently known however, if any causal relationship exists between these two aspects of MerTK function. We sought to determine if dendritic cells (DC) from mice lacking MerTK (mertk(- / - ) mice) have characteristics that may aid in the development of B cell autoimmunity. Specifically, we found that mertk(- / - ) mice contain an elevated number of splenic DC, and this population contains an elevated proportion of cells secreting the critical B cell pro-survival factor, B cell activating factor (BAFF). Elevated numbers of BAFF-secreting cells were also detected among mertk(- / - ) bone marrow-derived dendritic cell (BMDC) populations. This was observed in both resting BMDC, and BMDC stimulated with lipopolysaccharide (LPS) or treated with exogenous apoptotic cells. We also found that DC in general have a pro-survival effect on resting B cells in co-culture. However, despite containing more BAFF-secreting cells, mertk(- / - ) BMDC were not superior to C57BL/6 or baff-deficient BMDC at promoting B cell survival. Furthermore, using decoy receptors, we show that DC may promote B cell survival and autoimmunity through a BAFF-and a proliferation-inducing ligand-independent mechanism.

Noh voice quality

In Noh, a traditional performing art of Japan, extremely expressive voice quality is used to convey an emotional message. A periodicity of voice appears responsible for these special effects. Acoustic signals were recorded for selected portions of dramatic singing in order to study the acoustic effects of delicate voice control by a master of the Konparu school. Using a signal analysis-synthesis algorithm, TANDEM-STRAIGHT, to represent multiple candidates for pitch perception, signals deviating from the harmonic structure have been successfully displayed, corresponding to auditory impressions of pitch movements, even when narrow-band spectrograms failed to show the perceived events. Strong interaction between vocal tract resonance and vocal fold vibration seems to play a major role in producing these expressive voice qualities.

EPR, ENDOR, and special TRIPLE measurements of P(*+) in wild type and modified reaction centers from Rb. sphaeroides

The influence of the protein environment on the primary electron donor, P, a bacteriochlorophyll a dimer, of reaction centers from Rhodobacter sphaeroides, has been investigated using electron paramagnetic resonance and electron nuclear double resonance spectroscopy. These techniques were used to probe the effects on P that are due to alteration of three amino acid residues, His L168, Asn L170, and Asn M199. The introduction of Glu at L168, Asp at L170, or Asp at M199 changes the oxidation/reduction midpoint potential of P in a pH-dependent manner (Williams et al. (2001) Biochemistry 40, 15403-15407). For the double mutant His L168 to Glu and Asn at L170 to Asp, excitation results in electron transfer along the A-side branch of cofactors at pH 7.2, but at pH 9.5, a long-lived state involving B-side cofactors is produced (Haffa et al. (2004) J Phys Chem B 108, 4-7). Using electron paramagnetic resonance spectroscopy, the mutants with alterations of each of the three individual residues and a double mutant, with changes at L168 and L170, were found to have increased linewidths of 10.1-11.0 G compared to the linewidth of 9.6 G for wild type. The Special TRIPLE spectra were pH dependent, and at pH 8, the introduction of aspartate at L170 increased the spin density ratio, rho (L)/rho (M), to 6.1 while an aspartate at the symmetry related position, M199, decreased the ratio to 0.7 compared to the value of 2.1 for wild type. These results indicate that the energy of the two halves of P changes by about 100 meV due to the mutations and are consistent with the interpretation that electrostatic interactions involving these amino acid residues contribute to the switch in pathway of electron transfer.

Comparison of bacterial reaction centers and photosystem II

In photosynthetic organisms, the utilization of solar energy to drive electron and proton transfer reactions across membranes is performed by pigment-protein complexes including bacterial reaction centers (BRCs) and photosystem II. The well-characterized BRC has served as a structural and functional model for the evolutionarily-related photosystem II for many years. Even though these complexes transfer electrons and protons across cell membranes in analogous manners, they utilize different secondary electron donors. Photosystem II has the unique ability to abstract electrons from water, while BRCs use molecules with much lower potentials as electron donors. This article compares the two complexes and reviews the factors that give rise to the functional differences. Also discussed are the modifications that have been performed on BRCs so that they perform reactions, such as amino acid and metal oxidation, which occur in photosystem II.

Exclusive branching-fraction measurements of semileptonic tau decays into three charged hadrons, into phipi(-)nu tau, and into phi K(-)nu tau

Using a data sample corresponding to an integrated luminosity of 342 fb(-1) collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy near 10.58 GeV, we measure B(tau(-)--> pi(-)pi(-)pi+nu(tau)(ex.K(S0))=(8.83+/-0.01+/-0.13)%, B(tau(-) -->K(-)pi(-)pi+nu tau(ex.K(S0))=(0.273+/-0.002+/-0.009)%, B(tau(-) -->K(-)pi(-)K+nu tau)=(0.1346+/-0.0010+/-0.0036)%, and B(tau(-) -->K(-)K(-)K+nu tau)=(1.58+/-0.13+/-0.12)x10;{-5}, where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B(tau(-) -->K(-)K(-)K+nu tau) in which no resonance structure is assumed. We also report a first measurement of B(tau(-) -->var phi(-)nu tau)=(3.42+/-0.55+/-0.25)x10(-5), a new measurement of B(tau(-) -->var phi K(-)nu tau)=(3.39+/-0.20+/-0.28)x10(-5) and a first upper limit on B(tau(-) -->K(-)K(-)K+nu tau(ex.var phi)).

Three-dimensional hydrogel cultures for modeling changes in tissue impedance around microfabricated neural probes

One limitation to the use of neuroprosthestic devices for chronic application, in the treatment of disease, is the reactive cell responses that occur surrounding the device after insertion. These cell and tissue responses result in increases in device impedance and failure of the device to interact with target populations of neurons. However, few tools are available to assess which components of the reactive response contribute most to changes in tissue impedance. An in vitro culture system has been developed that is capable of assessing individual components of the reactive response. The system utilizes alginate cell encapsulation to construct three-dimensional architectures that approach the cell densities found in rat cortex. The system was constructed around neuroNexus acute probes with on-board circuitry capable of monitoring the electrical properties of the surrounding tissue. This study demonstrates the utility of the system by demonstrating that differences in cell density within the three-dimensional alginate constructs result in differences in resistance and capacitance as measured by electrochemical impedance spectroscopy. We propose that this system can be used to model components of the reactive responses in brain tissue, and that the measurements recorded in vitro are comparable to measurements recorded in vivo.

Bias voltages at microelectrodes change neural interface properties in vivo

Rejuvenation of iridium microelectrode sites, which involves applying a 1.5 V bias for 4 s, has been shown to reduce site impedances of chronically implanted microelectrode arrays. This study applied complex impedance spectroscopy measurements to an equivalent circuit model of the electrode-tissue interface. Rejuvenation was found to cause a transient increase in electrode conductivity through an IrO2 layer and a decrease in the surrounding extracellular resistance by 85 +/- 1% (n=73, t-test p < 0.001) and a decrease in the immediate site resistance by 44 +/- 7% (n=73, t-test p<0.001). These findings may be useful as an intervention strategy to prolong the lifetime of chronic microelectrode implants for neuroprostheses.

Multilayer PDMS microfluidic chamber for controlling brain slice microenvironment

A novel three-layer microfluidic polydimethylsiloxane (PDMS) device was constructed with two fluid chambers that holds a brain slice in place with microposts while maintaining laminar perfusate flow above and below the slice. Our fabrication technique permits rapid production of PDMS layers that can be applied to brain slices of different shapes and sizes. In this study, the device was designed to fit the shape and thickness (530-700 microm) of a medullary brain slice taken from P0-P4 neonatal rats. Medullary slices in this chamber spontaneously produced rhythmic, respiratory-related motor output for up to 3 h, thereby demonstrating that brain slice viability was maintained for prolonged periods. This design is unique in that it achieves independent control of fluids through multiple channels in two separate fluid chambers. The laminar flow exhibited by the microfluidic chamber allows controlled solutions to target specific areas of the brain slice based on the input flow rates. To demonstrate this capability, a stream of Na(+)-free solution was focused on one half of a medullary slice to abolish spontaneous neural activity in only that half of the brain slice, while the other half remained active. We also demonstrated that flow of different solutions can be focused over the midline of the brain slice. The multilayer brain slice chamber design can integrate several traditional types of electrophysiology tools that are commonly used to measure neurophysiological properties of brain slices. Thus, this new microfluidic chamber is advantageous for experiments that involve controlled drug or solution delivery at high spatiotemporal resolution.

Evidence of a broad structure at an invariant mass of 4.32 GeV/c2 in the reaction e+e- --> pi+pi-psi(2S) measured at BABAR

We present a measurement of the cross section of the process e(+)e(-)-->pi(+)pi(-)psi(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the SLAC PEP-II e(+)e(-) storage rings. The study is based on 298 fb(-1) of data recorded with the BABAR detector. A structure is observed in the cross section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the Y(4260) previously reported by this experiment.

Measurement of branching fractions and mass spectra of B-->Kpipigamma

We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B-->Kpipigamma in the range m(Kpipi)<1.8 GeV/c(2). We reconstruct four final states: K(+)pi(-)pi(+)gamma, K(+)pi(-)pi(0)gamma, K(S)(0)pi(-)pi(+)gamma, and K(S)(0)pi(+)pi(0)gamma, where K(S)(0)-->pi(+)pi(-). Using 232 x 10(6) e(+)e(-)-->BB events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B(+)-->K(+)pi(-)pi(+)gamma)=[2.95+/-0.13(stat)+/-0.20(syst)] x 10(-5), B(B(0)-->K(+)pi(-)pi(0)gamma)=[4.07+/-0.22(stat)+/-0.31(syst)] x 10(-5), B(B(0)-->K(0)pi(+)pi(-)gamma)=[1.85+/-0.21(stat)+/-0.12(syst)] x 10(-5), and B(B(+)-->K(0)pi(+)pi(0)gamma)=[4.56+/-0.42(stat)+/-0.31(syst)] x 10(-5).