Benefit of a Contralateral Routing of Signal Device for Unilateral Cochlear Implant Users.

Objective: To investigate objective and subjective effects of an adjunctive contralateral routing of signal (CROS) device at the untreated ear in patients with a unilateral cochlear implant (CI). Design: Prospective study of 10 adult experienced unilateral CI users with bilateral severe-to-profound hearing loss. Speech in noise reception (SNR) and sound localization were measured with and without the additional CROS device. SNR was measured by applying speech signals at the untreated/CROS side while noise signals came from the front (S90N0). For S0N90, signal sources were switched. Sound localization was measured in a 12-loudspeaker full circle setup. To evaluate the subjective benefit, patients tried the device for 2 weeks at home, then filled out the abbreviated Speech, Spatial and Qualities of Hearing Scale as well as the Bern benefit in single-sided deafness questionnaires. Results: In the setting S90N0, all patients showed a highly significant SNR improvement when wearing the additional CROS device (mean 6.4 dB, p < 0.001). In the unfavorable setting S0N90, only a minor deterioration of speech understanding was noted (mean -0.66 dB, p = 0.54). Sound localization did not improve substantially with CROS. In the two questionnaires, 12 of 14 items showed an improvement in mean values, but none of them was statistically significant. Conclusion: Patients with unilateral CI benefit from a contralateral CROS device, particularly in a noisy environment, when speech comes from the CROS ear side. © 2014 S. Karger AG, Basel.

Quality standards for bone conduction implants.

CONCLUSION Bone conduction implants are useful in patients with conductive and mixed hearing loss for whom conventional surgery or hearing aids are no longer an option. They may also be used in patients affected by single-sided deafness. OBJECTIVES To establish a consensus on the quality standards required for centers willing to create a bone conduction implant program. METHOD To ensure a consistently high level of service and to provide patients with the best possible solution the members of the HEARRING network have established a set of quality standards for bone conduction implants. These standards constitute a realistic minimum attainable by all implant clinics and should be employed alongside current best practice guidelines. RESULTS Fifteen items are thoroughly analyzed. They include team structure, accommodation and clinical facilities, selection criteria, evaluation process, complete preoperative and surgical information, postoperative fitting and assessment, follow-up, device failure, clinical management, transfer of care and patient complaints.

Design, Calibration, and Evaluation of Depth-of-Interaction-Capable PET Detector Modules

High-resolution, small-bore PET systems suffer from a tradeoff between system sensitivity, and image quality degradation. In these systems long crystals allow mispositioning of the line of response due to parallax error and this mispositioning causes resolution blurring, but long crystals are necessary for high system sensitivity. One means to allow long crystals without introducing parallax errors is to determine the depth of interaction (DOI) of the gamma ray interaction within the detector module. While DOI has been investigated previously, newly available solid state photomultipliers (SSPMs) well-suited to PET applications and allow new modules for investigation. Depth of interaction in full modules is a relatively new field, and so even if high performance DOI capable modules were available, the appropriate means to characterize and calibrate the modules are not. This work presents an investigation of DOI capable arrays and techniques for characterizing and calibrating those modules. The methods introduced here accurately and reliably characterize and calibrate energy, timing, and event interaction positioning. Additionally presented is a characterization of the spatial resolution of DOI capable modules and a measurement of DOI effects for different angles between detector modules. These arrays have been built into a prototype PET system that delivers better than 2.0 mm resolution with a single-sided-stopping-power in excess of 95% for 511 keV g's. The noise properties of SSPMs scale with the active area of the detector face, and so the best signal-to-noise ratio is possible with parallel readout of each SSPM photodetector pixel rather than multiplexing signals together. This work additionally investigates several algorithms for improving timing performance using timing information from multiple SSPM pixels when light is distributed among several photodetectors.

Anaerobic methanotrophic archaea-2 and Desulfosarcina/Desulfococcus group in sediments at different stations

The anaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor is mediated by consortia of methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). In sediment samples from Hydrate Ridge, the Isis Mud Volcano and the Gulf of Mexico, DSS cells accounted for 3-6% of all DAPI-stained single cells. Out of these, 8-17% were labelled with probe SEEP1a-1441. This translated into relative abundances of single SEEP-SRB1a cells of 0.3% to 0.7%. Contrastingly, in a sediment sample from the Gullfaks oil field, DSS cells accounted for 18% and SEEP-SRB1a for 9% of all single cells. This sediment sample also featured an unusually high abundance of single ANME-2 cells and only very few ANME-2/DSS aggregates in comparison with other AOM habitats. Considering also the nature of the sample, it is likely that the high number of single ANME-2 and SEEP-SRB1a cells were an artifact of sample preparation. Here, harsher sonication was required to remove the microorganisms from coarse sand prior to CARD-FISH analysis.

Nanotechnology for more efficient photovoltaics: the quantum dot intermediate band solar cell

The intermediate band solar cell [1] has been proposed as a concept able to substantially enhance the efficiency limit of an ordinary single junction solar cell. If a band permitted for electrons is inserted within the forbidden band of a semiconductor then a novel path for photo generation is open: electron hole pairs may be formed by the successive absorption of two sub band gap photons using the intermediate band (IB) as a stepping stone. While the increase of the photovoltaic (PV) current is not a big achievement —it suffices to reduce the band gap— the achievement of this extra current at high voltage is the key of the IB concept. In ordinary cells the voltage is limited by the band gap so that reducing it would also reduce the band gap. In the intermediate band solar cell the high voltage is produced when the IB is permitted to have a Quasi Fermi Level (QFL) different from those of the Conduction Band (CB) and the Valence Band (VB). For it the cell must be properly isolated from the external contacts, which is achieved by putting the IB material between two n- and p-type ordinary semiconductors [2]. Efficiency thermodynamic limit of 63% is obtained for the IB solar cell1 vs. the 40% obtained [3] for ordinary single junction solar cells. Detailed information about the IB solar cells can be found elsewhere [4].

Real-time reliability test for a CPV module based on a power degradation model

Models based on degradation are powerful and useful tools to evaluate the reliability of those devices in which failure happens because of degradation in the performance parameters. This paper presents a procedure for assessing the reliability of concentrator photovoltaic (CPV) modules operating outdoors in real-time conditions. With this model, the main reliability functions are predicted. This model has been applied to a real case with a module composed of GaAs single-junction solar cells and total internal reflection (TIR) optics

Understanding experimental characterization of intermediate band solar cell

An intermediate band solar cell is a novel photovoltaic device with the potential to exceed the efficiency of single gap solar cells. In the last few years, several prototypes of these cells, based on different technologies, have been reported. Since these devices do not yet perform ideally, it is sometimes difficult to determine to what extent they operate as actual intermediate band solar cells. In this article we provide the essential guidelines to interpret conventional experimental results (current-voltage plots, quantum efficiency, etc.) associated with their characterization. A correct interpretation of these results is essential in order not to mislead the research efforts directed towards the improvement of the efficiency of these devices.

Guide to intermediate band solar cell research

The intermediate band solar cell (IBSC) is a solar cell that, in order to increase its efficiency over that of single gap solar cells, takes advantage of the absorption of below-bandgap energy photons by means of an intermediate band (IB) located in the semiconductor bandgap. For this process to improve the solar cell performance, the belowbandgap photon absorption has to be effective and the IB cannot limit the open-circuit voltage of the cell. In this paper we provide a guide to the new researcher interested in the idea in order he can quickly become familiar with the concept and updated with the most relevant experimental results.

Max Bill: variaciones sobre la búsqueda de la belleza

Max Bill es un artista lógico. Quince variaciones sobre el mismo tema 1938, podría ser el epítome de la lógica de Bill: la obra como resultado de la aplicación de leyes distintas sobre una estructura de orden. La gran diversidad formal de la obra de Max Bill –entre sus diseños de objetos, su tipografía, su pintura, su escultura o su arquitectura no parece haber líneas formales evidentes- se debe a que, para él, cada tarea es diferente y depende de medios y leyes propios. Una diversidad que podría ser erróneamente interpretada como un tipo de eclecticismo. Su conferencia en el Werkbund suizo de 1948 “belleza de la función, belleza como función”, se aleja del discurso funcionalista al proponer la belleza como una igual al resto de funciones. Cada obra ha de satisfacer la finalidad para la que ha sido construida y cumplir todas las funciones que en ella intervienen pero, además, ha de ser bella. La particularidad de Bill estriba en que, reconociéndose a sí mismo como un artista lógico, incluye la belleza como una más de las funciones a cumplir por cualquier objeto. Su famoso aforismo en relación a la configuración del entorno, desde la cuchara a la ciudad, incluiría la arquitectura en el ámbito de los objetos que han de cumplir esta nueva función. La búsqueda de la belleza será una constante en su obra. No una belleza generalizable y determinada a priori, sino una belleza entendida como predicado singular, individualizada para cada tarea. De este modo, podemos analizar, alternativamente, la belleza lógica de sus construcciones geométricas y la belleza simbólica de sus monumentos; la belleza del espacio sin fin en las superficies de una sola cara y la belleza prefabricada en sus más austeras realizaciones; la belleza elemental de sus esculturas y la belleza corriente con que sus arquitecturas se integran en la ciudad. Podemos plantearnos la posibilidad de una belleza de la estructura y entender simultáneamente la belleza cruda de su obra maestra, los edificios de la Escuela de Ulm. La búsqueda de la belleza nos ayudará a entender que, en la obra de Bill, la razón intuitiva -como modo de conocimiento- toma mayor importancia de la que parece. La forma como suma de todas las funciones en unidad armónica, será el resultado de un adecuado equilibrio entre razón lógica y razón intuitiva. ABSTRACT Max Bill is a logical artist. We could consider “Fitfteen variations on the same theme”, 1938, as the Bill’s logic epitome: the work as a result of the application of different tectonic laws on the order structure. The variety of the form in Bill’s work –his designed objects, his typography, his painting, his sculpture, or his architecture do not seem to have, between them, a direct line connecting the form- is due to the fact that, for him, each task is different and it depends on the own means and tectonic laws. A kind of diversity that could be misinterpreted like certain type of eclecticism. His lecture at the Suisse Werkbund (1948) “beauty from function and as function” is far from the functionalist speech, when proposing beauty as an equal to the rest of functions. In his own words, each work has to satisfy the purpose it was built for and fulfill all functions, and furthermore it has to be beautiful. Seeing himself as a logical artist, Bill however introduces beauty as one more of the functions that any object has to fulfill. His famous aphorism related to the environment management, from the spoon to the city, would include architecture as one more of the objects that have to satisfy this new function. The pursuit of beauty is a constant in his work. It won’t be a general beauty determined in advance, but a singular predicate, individualized for each task. That way, we can analyze, alternatively, the logical beauty of his geometric constructions and the symbolical beauty of his monuments; the beauty of the endless space in the single-sided surfaces and the prefabricated beauty in his most stricts constructions; the elemental beauty of his sculptures and the ordinary beauty with which some of his architectures are integrated in the city. We can also try the possibility of a beauty from the structure and understand, at the same time, the raw beauty of his architectural masterpiece, the buildings of the Ulm School of Design. The pursuit of beauty in Bill’s work will help us to understand that intuitive reason, as a way of knowledge, takes more importance than it seems. Form, as the harmonious expression of the sum of all functions, will be the result of an appropriate balance between logical and intuitive reason.

Ultra high temperature latent heat energy storage and thermophotovoltaic energy conversion

A conceptual energy storage system design that utilizes ultra high temperature phase change materials is presented. In this system, the energy is stored in the form of latent heat and converted to electricity upon demand by TPV (thermophotovoltaic) cells. Silicon is considered in this study as PCM (phase change material) due to its extremely high latent heat (1800 J/g or 500 Wh/kg), melting point (1410 C), thermal conductivity (~25 W/mK), low cost (less than $2/kg or $4/kWh) and abundance on earth. The proposed system enables an enormous thermal energy storage density of ~1 MWh/m3, which is 10e20 times higher than that of lead-acid batteries, 2e6 times than that of Li-ion batteries and 5e10 times than that of the current state of the art LHTES systems utilized in CSP (concentrated solar power) applications. The discharge efficiency of the system is ultimately determined by the TPV converter, which theoretically can exceed 50%. However, realistic discharge efficiencies utilizing single junction TPV cells are in the range of 20e45%, depending on the semiconductor bandgap and quality, and the photon recycling efficiency. This concept has the potential to achieve output electric energy densities in the range of 200-450 kWhe/m3, which is comparable to the best performing state of the art Lithium-ion batteries.

Slow cycling of unphosphorylated myosin is inhibited by calponin, thus keeping smooth muscle relaxed

A key unanswered question in smooth muscle biology is whether phosphorylation of the myosin regulatory light chain (RLC) is sufficient for regulation of contraction, or if thin-filament-based regulatory systems also contribute to this process. To address this issue, the endogenous RLC was extracted from single smooth muscle cells and replaced with either a thiophosphorylated RLC or a mutant RLC (T18A/S19A) that cannot be phosphorylated by myosin light chain kinase. The actin-binding protein calponin was also extracted. Following photolysis of caged ATP, cells without calponin that contained a nonphosphorylatable RLC shortened at 30% of the velocity and produced 65% of the isometric force of cells reconstituted with the thiophosphorylated RLC. The contraction of cells reconstituted with nonphosphorylatable RLC was, however, specifically suppressed in cells that contained calponin. These results indicate that calponin is required to maintain cells in a relaxed state, and that in the absence of this inhibition, dephosphorylated cross-bridges can slowly cycle and generate force. These findings thus provide a possible framework for understanding the development of latch contraction, a widely studied but poorly understood feature of smooth muscle.

Identification of an early T cell progenitor for a pathway of T cell maturation in the bone marrow

We have identified a rare (≈0.05–0.1%) population of cells (Thy-1hiCD16+CD44hiCD2−TCRαβ−B220−Mac-1−NK1.1−) in the adult mouse bone marrow that generates CD4+ and CD8+ TCRαβ+ T cells after tissue culture for 48 hr in the presence of Ly5 congenic marrow cells. The essential stages in the maturation of the progenitors were determined; the stages included an early transition from CD2−CD16+CD44hiTCRαβ− to CD2+CD16int/−CD44int/−TCRαβ− cells, and a later transition to CD4+CD8+TCRαβ+ double-positive T cells that rapidly generate the CD4+ and CD8+ single-positive T cells. The maturation of the progenitors is almost completely arrested at the CD2+TCRαβ− stage by the presence of mature T cells at the initiation of cultures. This alternate pathway is supported by the marrow microenvironment; it recapitulates critical intermediary steps in intrathymic T cell maturation.

Deciphering a neural code for vision

Deciphering the information that eyes, ears, and other sensory organs transmit to the brain is important for understanding the neural basis of behavior. Recordings from single sensory nerve cells have yielded useful insights, but single neurons generally do not mediate behavior; networks of neurons do. Monitoring the activity of all cells in a neural network of a behaving animal, however, is not yet possible. Taking an alternative approach, we used a realistic cell-based model to compute the ensemble of neural activity generated by one sensory organ, the lateral eye of the horseshoe crab, Limulus polyphemus. We studied how the neural network of this eye encodes natural scenes by presenting to the model movies recorded with a video camera mounted above the eye of an animal that was exploring its underwater habitat. Model predictions were confirmed by simultaneously recording responses from single optic nerve fibers of the same animal. We report here that the eye transmits to the brain robust “neural images” of objects having the size, contrast, and motion of potential mates. The neural code for such objects is not found in ambiguous messages of individual optic nerve fibers but rather in patterns of coherent activity that extend over small ensembles of nerve fibers and are bound together by stimulus motion. Integrative properties of neurons in the first synaptic layer of the brain appear well suited to detecting the patterns of coherent activity. Neural coding by this relatively simple eye helps explain how horseshoe crabs find mates and may lead to a better understanding of how more complex sensory organs process information.

New Alleles of the Yeast MPS1 Gene Reveal Multiple Requirements in Spindle Pole Body Duplication

In Saccharomyces cerevisiae, the Mps1p protein kinase is critical for both spindle pole body (SPB) duplication and the mitotic spindle assembly checkpoint. The mps1–1 mutation causes failure early in SPB duplication, and because the spindle assembly checkpoint is also compromised, mps1–1 cells proceed with a monopolar mitosis and rapidly lose viability. Here we report the genetic and molecular characterization of mps1–1 and five new temperature-sensitive alleles of MPS1. Each of the six alleles contains a single point mutation in the region of the gene encoding the protein kinase domain. The mutations affect several residues conserved among protein kinases, most notably the invariant glutamate in subdomain III. In vivo and in vitro kinase activity of the six epitope-tagged mutant proteins varies widely. Only two display appreciable in vitro activity, and interestingly, this activity is not thermolabile under the assay conditions used. While five of the six alleles cause SPB duplication to fail early, yielding cells with a single SPB, mps1–737 cells proceed into SPB duplication and assemble a second SPB that is structurally defective. This phenotype, together with the observation of intragenic complementation between this unique allele and two others, suggests that Mps1p is required for multiple events in SPB duplication.

Two-dimensional confocal images of organization, density, and gating of focal Ca2+ release sites in rat cardiac myocytes

In cardiac myocytes Ca2+ cross-signaling between Ca2+ channels and ryanodine receptors takes place by exchange of Ca2+ signals in microdomains surrounding dyadic junctions, allowing first the activation and then the inactivation of the two Ca2+-transporting proteins. To explore the details of Ca2+ signaling between the two sets of receptors we measured the two-dimensional cellular distribution of Ca2+ at 240 Hz by using a novel confocal imaging technique. Ca2+ channel-triggered Ca2+ transients could be resolved into dynamic “Ca2+ stripes” composed of hundreds of discrete focal Ca2+ releases, appearing as bright fluorescence spots (radius ≅ 0.5 μm) at reproducible sites, which often coincided with t-tubules as visualized with fluorescent staining of the cell membrane. Focal Ca2+ releases triggered stochastically by Ca2+ current (ICa) changed little in duration (≅7 ms) and size (≅100,000 Ca ions) between −40 and +60 mV, but their frequency of activation and first latency mirrored the kinetics and voltage dependence of ICa. The resolution of 0.95 ± 0.13 reproducible focal Ca2+ release sites per μm3 in highly Ca2+-buffered cells, where diffusion of Ca2+ is limited to 50 nm, suggests the presence of about one independent, functional Ca2+ release site per half sarcomere. The density and distribution of Ca2+ release sites suggest they correspond to dyadic junctions. The abrupt onset and termination of focal Ca2+ releases indicate that the cluster of ryanodine receptors in individual dyadic junctions may operate in a coordinated fashion.