In the original article, there was an error in the reported percentage and number of A24b/M2 axons with activity onsets that precede running onset. The percentage of A24b/M2 axons with significant running onset responses that precede running onset is 30% (508 of 1,675). All analysis based on these numbers and Figure S2, which shows the same data, were correct. This error does not affect any of the conclusions of the study. In addition, there was an error in the methods in the description of the timing of the injection of the ibotenic acid for the chronic lesions of A24b. Ibotenic acid was injected 24 hr prior to the imaging experiments. The authors regret these errors and any confusion that may have arisen as a result of them. These errors have now been corrected in the article online.

A unitary bioresorbable cage/core bone graft substitute consisting of a stiff cage and a softer core with interconnected porosity is offered for spinal arthrodesis. Polycaprolactone, PCL, was used as the matrix and hydroxyapatite, HA, and β-tricalcium phosphate, TCP, were used in the formulation of the cage layer to impart modulus increase and osteoconductivity while the core consisted solely of PCL. The crystallinity, biodegradation rate (under accelerated conditions) and mechanical properties, i.e., the uniaxial compression, relaxation modulus upon step compression and cyclic compressive fatigue properties, of the co-extruded cage/core bone graft substitutes could be manipulated by changes in the concentration of HA/TCP in the cage layer. The cyclic fatigue behavior of the cage/core bone graft substitutes were also compared to the behavior of bovine vertebral cancellous bone characterized under similar testing conditions. The biocompatibility of the cage/core bone graft substitutes were assessed via in vitro culturing of human bone marrow derived stromal cells, BMSCs. The cell proliferation rates, time dependencies of the alkaline phosphates (ALP) activity and the expressions of bone markers, i.e., Runx2, ALP, collagen type I, osteopontin and osteocalcin, and the collected μ-CT images demonstrated the differentiation of BMSCs via osteogenic lineage and formation of mineralized bone tissue to indicate the biocompatibility of the cage/core bone graft substitutes.

We introduce a silicon metal-oxide-semiconductor quantum dot architecture based on a single polysilicon gate stack. The elementary structure consists of two enhancement gates separated spatially by a gap, one gate forming a reservoir and the other a quantum dot. We demonstrate, in three devices based on two different versions of this elementary structure, that a wide range of tunnel rates is attainable while maintaining single-electron occupation. A characteristic change in slope of the charge transitions as a function of the reservoir gate voltage, attributed to screening from charges in the reservoir, is observed in all devices, and is expected to play a role in the sizable tuning orthogonality of the split enhancement gate structure. The all-silicon process is expected to minimize strain gradients from electrode thermal mismatch, while the single gate layer should avoid issues related to overlayers (e.g., additional dielectric charge noise) and help improve yield. Finally, reservoir gate control of the tunnel barrier has implications for initialization, manipulation and readout schemes in multi-quantum dot architectures.Silicon (Si) quantum dots (QDs) are strong contenders for the realization of spin qubits. 1,2 Silicon germanium heterostructure (Si/SiGe) platforms with integrated micromagnets 3 have produced the highest performance qubits, 4-6 with fidelities over 99.9%, 7 while metal-oxidesemiconductor (MOS) platforms have also achieved fault tolerant fidelities. 8 Most of the high performance systems mentioned above are enhancement mode devices comprising at least two layers of control gates. The overlapping gates ensure strong confinement and the highest electrostatic control over regions surrounding the QDs. These current multi-stack devices have therefore achieved excellent tunability, thanks in part to an independant control of reservoirs, dots and tunnel barriers through respectively dedicated gates. On the other hand, single-layer enhancement mode devices are being explored for ease of fabrication and potentially higher yield, in both Si/SiGe and MOS systems. [9][10][11][12][13] In particular, all-silicon MOS single-layer devices are expected to avoid thermal mismatch and additional dielectric charge noise from overlayers. 14,15 These single-layer devices generally use a single gate to form a source-dot-drain channel, relying on constrictions and lateral depletion gates to shape the confinement potential. 9,16 Reservoir filling, dot charge occupation and tunnel rates are therefore controlled differently than in multi-gate stack architectures. Various architectures and methods of tunnel barrier control impact tunability differently, and understanding those differences will influence choices of multi-QDs initialization, manipulation and readout schemes, including automatic tuning procedures, 17,18 as well as reproducibility, versatility and scalability of devices. 19 Here we explore a single gate stack structure featuring a split gate for dot and reservoir formation. The tunnel barrier is a) S. Rochet...

Conventional electrospinning is a simple process, suitable for the processing of solvated polymers at relatively low rates. It lacks the capabilities of conveying of solids, mixing of polymeric resins and devolatilization and has limited capabilities in melting and incorporation of fillers, including nanoparticles. The use of a twin screw extruder as the front end of the electrospinning process provides these capabilities but only becomes feasible at relatively high throughput rates. Such high rates of electrospinning can only be achieved by using multi‐nozzle spinnerets. However, the dynamics of electrospinning processes using multi‐nozzle spinnerets has not been well studied. Here a multi‐nozzle spinneret attached to a hybrid twin screw extrusion and electrospinning apparatus was employed for the characterization of the dynamics in terms of the electrospun mesh thickness distributions of poly(caprolactone), PCL, as a function of the principal parameters of the electrospinning process, i.e., applied voltage, distance of separation between the spinneret die, and the collector, i.e., a conductive mandrel, and its rotational speed. PCL fiber diameter and orientation distributions, as well as the thickness, crystallinity, and mechanical properties of the non‐woven meshes, were characterized to gain a basic understanding of how the electrospun mesh properties develop as a function of process parameters in the multi‐nozzle configuration. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

High-fidelity single-shot readout of spin qubits requires distinguishing states much faster than the T1 time of the spin state. One approach to improving readout fidelity and bandwidth (BW) is cryogenic amplification, where the signal from the qubit is amplified before noise sources are introduced and room-temperature amplifiers can operate at lower gain and higher BW. We compare the performance of two cryogenic amplification circuits: a current-biased heterojunction bipolar transistor circuit (CB-HBT), and an AC-coupled HBT circuit (AC-HBT). Both circuits are mounted on the mixing-chamber stage of a dilution refrigerator and are connected to silicon metal oxide semiconductor (Si-MOS) quantum dot devices on a printed circuit board (PCB). The power dissipated by the CB-HBT ranges from 0.1 to 1 μW whereas the power of the AC-HBT ranges from 1 to 20 μW. Referred to the input, the noise spectral density is low for both circuits, in the 15 to 30 fA/ range. The charge sensitivity for the CB-HBT and AC-HBT is 330 μe/ and 400 μe/, respectively. For the single-shot readout performed, less than 10 μs is required for both circuits to achieve bit error rates below 10−3, which is a putative threshold for quantum error correction.