Focal cooling: An alternative treatment for drug-resistant epilepsy in a mesial temporal lobe epilepsy primate model-A preliminary study.

OBJECTIVE: Focal cooling is emerging as a relevant therapy for drug-resistant epilepsy (DRE). However, we lack data on its effectiveness in controlling seizures that originate in deep-seated areas like the hippocampus. We present a thermoelectric solution for focal brain cooling that specifically targets these brain structures. METHODS: A prototype implantable device was developed, including temperature sensors and a cannula for penicillin injection to create an epileptogenic zone (EZ) near the cooling tip in a non-human primate model of epilepsy. The mesial temporal lobe was targeted with repeated penicillin injections into the hippocampus. Signals were recorded from an sEEG (Stereoelectroencephalography) lead placed 2 mm from the EZ. Once the number of seizures had stabilized, focal cooling was applied, and temperature and electroclinical events were monitored using a customized detection algorithm. Tests were performed on two Macaca fascicularis monkeys at three temperatures. RESULTS: Hippocampal seizures were observed 40-120 min post-injection, their duration and frequency stabilized at around 120 min. Compared to the control condition, a reduction in the number of hippocampal seizures was observed with cooling to 21°C (Control: 4.34 seizures, SD 1.704 per 20 min vs Cooling to 21°C: 1.38 seizures, SD 1.004 per 20 min). The effect was more pronounced with cooling to 17°C, resulting in an almost 80% reduction in seizure frequency. Seizure duration and number of interictal discharges were unchanged following focal cooling. After several months of repeated penicillin injections, hippocampal sclerosis was observed, similar to that recorded in humans. In addition, seizures were identified by detecting temperature variations of 0.3°C in the EZ correlated with the start of the seizures. SIGNIFICANCE: In epilepsy therapy, the ultimate aim is total seizure control with minimal side effects. Focal cooling of the EZ could offer an alternative to surgery and to existing neuromodulation devices.

Let's twist again: elasto-capillary assembly of parallel ribbons.

We show the self-assembly through twisting and bending of side by side ribbons under the action of capillary forces. Micro-ribbons made of silicon nitride are batch assembled at the wafer scale. We study their assembly as a function of their dimensions and separating distance. Model experiments are carried out at the macroscopic scale where the tension in ribbons can easily be tuned. The process is modeled considering the competition between capillary, elastic and tension forces. Theory shows a good agreement for macroscale assemblies, while the accuracy is within 30% at the micrometer scale. This simple self-assembly technique yields highly symmetric and controllable structures which could be used for batch fabrication of functional 3D micro-structures.

The nurse scheduling problem in real-life.

The aim of this paper is to study the scheduling process for two types of nursing teams, regular teams from care units and the float team that covers for shortages in the hospital. When managers address this problem, they either use a manual approach or have to invest in expensive commercial tool. We propose a simple heuristic approach, flexible and easy enough to be implemented on spreadsheets, and requiring almost no investment. The approach leads to streamlined process and higher-quality schedules for nurses. The multi-objective model and heuristics are presented, and additional analysis is performed to compare the performance of the approach. We show that our approach compares very well with an optimization software (CPLEX solver) and may be implemented at no cost. It addresses the lack of choice between either manual solution method or a commercial package at a high cost.

Straightforward Integration Flow of a Silicon-Containing Block Copolymer for Line-Space Patterning.

A promising alternative for the next-generation lithography is based on the directed self-assembly of block copolymers (BCPs) used as a bottom-up tool for the definition of nanometric features. Herein, a straightforward integration flow for line-space patterning is reported for a silicon BCP system, that is, poly(1,1-dimethylsilacyclobutane)-b-poly(styrene) (PDMSB-b-PS), able to define sub 15 nm features. Both in-plane cylindrical (L0 = 20.7 nm) and out-of-plane lamellar structures (L0 = 23.2 nm) formed through a rapid thermal annealing-10 min at 180 °C-were successfully integrated using graphoepitaxy to provide a long-range ordering of the BCP structure without the use of underlayers or top coats. Subsequent deep transfer into the silicon substrate using the hardened oxidized PDMSB domains as a mask is demonstrated. Combining a rapid self-assembly behavior, straightforward integration, and an excellent etching contrast, PDMSB-b-PS may become a material of choice for the next-generation lithography.

Elasto-Capillary Folding Using Stop-Programmable Hinges Fabricated by 3D Micro-Machining.

We show elasto-capillary folding of silicon nitride objects with accurate folding angles between flaps of (70.6 ± 0.1)° and demonstrate the feasibility of such accurate micro-assembly with a final folding angle of 90°. The folding angle is defined by stop-programmable hinges that are fabricated starting from silicon molds employing accurate three-dimensional corner lithography. This nano-patterning method exploits the conformal deposition and the subsequent timed isotropic etching of a thin film in a 3D shaped silicon template. The technique leaves a residue of the thin film in sharp concave corners which can be used as an inversion mask in subsequent steps. Hinges designed to stop the folding at 70.6° were fabricated batchwise by machining the V-grooves obtained by KOH etching in (110) silicon wafers; 90° stop-programmable hinges were obtained starting from silicon molds obtained by dry etching on (100) wafers. The presented technique has potential to achieve any folding angle and opens a new route towards creating structures with increased complexity, which will ultimately lead to a novel method for device fabrication.

Online stochastic optimization of radiotherapy patient scheduling.

The effective management of a cancer treatment facility for radiation therapy depends mainly on optimizing the use of the linear accelerators. In this project, we schedule patients on these machines taking into account their priority for treatment, the maximum waiting time before the first treatment, and the treatment duration. We collaborate with the Centre Intégré de Cancérologie de Laval to determine the best scheduling policy. Furthermore, we integrate the uncertainty related to the arrival of patients at the center. We develop a hybrid method combining stochastic optimization and online optimization to better meet the needs of central planning. We use information on the future arrivals of patients to provide an accurate picture of the expected utilization of resources. Results based on real data show that our method outperforms the policies typically used in treatment centers.