Drag dynamics in one-dimensional Fermi systems

We study drag dynamics of several fermions in a fermion cloud in one-dimensional continuous systems, with particular emphasis on the non-trivial quantum many-body effects in systems whose parameters change gradually in real time. We adopt the Fermi--Hubbard model and the time-dependent density matrix renormalization group method to calculate the drag force on a trapped fermion cluster in a cloud of another fermion species with contact interaction. The simulation result shows that a non-trivial peak in the resistance force is observed in the high cloud density region, which implies a criterion of effective ways in diffusive transport in a fermion cloud. We compare the DMRG simulation result with a mean-field result, and it is suggested that some internal degrees of freedom have a crucial role in the excitation process when the cloud density is high. This work emphasizes the difference between the full-quantum calculation and the semiclassical calculation, which is the quantum effects, in slow dynamics of many-body systems bound in a fermion cloud.Comment: 7 pages, 8 figure

Collision of one-dimensional fermion clusters

We study cluster-cluster collisions in one-dimensional Fermi systems with particular emphasis on the non-trivial quantum effects of the collision dynamics. We adopt the Fermi-Hubbard model and the time-dependent density matrix renormalization group method to simulate collision dynamics between two fermion clusters of different spin states with contact interaction. It is elucidated that the quantum effects become extremely strong with the interaction strength, leading to the transmittance much more enhanced than expected from semiclassical approximation. We propose a concise model based on one-to-one collisions, which unveils the origin of the quantum effects and also explains the overall properties of the simulation results clearly. Our concise model can quite widely describe the one-dimensional collision dynamics with contact interaction. Some potential applications, such as repeated collisions, are addressed.Comment: 5 pages, 5 figure

Quantum effects on one-dimensional collision dynamics of fermion clusters

Recently, many experiments with cold atomic gases have been conducted from interest in the non-equilibrium dynamics of correlated quantum systems. Of these experiments, the mixing dynamics of fermion clusters motivates us to research cluster-cluster collision dynamics in one-dimensional Fermi systems. We adopt the one-dimensional Fermi-Hubbard model and apply the time-dependent density matrix renormalization group method. We simulate collisions between two fermion clusters of spin-up and spin-down, and calculate reflectance of the clusters R changing the particle number in each cluster and the interaction strength between two fermions with up and down spins. We also evaluate the quasi-classical (independent collision) reflectance R^{qc} to compare it with R. The quasi-classical picture is quantitatively valid in the limit of weak interaction, but it is not valid when interaction is strong.Comment: 3 pages, 4 figures, submitted to the proceedings for 26th International Conference on Low Temperature Physics (LT26

Non-traumatic Atypical Peri-implant Femoral Fracture at the Distal Screw after Short Femoral Nail Fixation for a Pertrochanteric Fracture

This is the second report of an atypical peri-implant femoral fracture occurring at the distal screw after intramedullary nail fixation of a pertrochanteric fracture. A 94-year-old Japanese female with a 5-year history of alendronate intake presented with prodromal pain in her right thigh after intramedullary nail fixation. Plain radiographs showed an incomplete noncomminuted transverse fracture at the distal screw, suggesting an atypical peri-implant femoral fracture. The pathogenesis of an atypical peri-implant femoral fracture could be a combined systemic bone metabolism disorder and repetitive overloading at the screw, similar to the pathogenesis of an atypical periprosthetic femoral fracture around stem implantation

Improvement of zone control induction heating equipment for high-speed processing of semiconductor devices

In order to process a semiconductor device of high quality, uniform heating is necessary, but it is not easy to heat uniformly with conventional induction heating equipment. To solve this problem, zone control induction heating equipment has been jointly developed. In this paper, we examine the effect of dividing an induction heater into several small coil groups having different current and frequency, using the finite-element method. We describe the heating characteristics of the zone control coil groups and show that nearly uniform heating is possible by controlling both current and frequency.</p

Extensive Bilateral Patellar Tendon Ossification in a Spinal Cord Injury Patient

This is the first report of extensive bilateral patellar tendon ossification occurring over a prolonged time after a unilateral knee injury. An 84-year-old Japanese man with a spinal cord injury caused by a burst fracture of the T12 vertebra presented with a bony hard prominence on the left knee, which was injured in a traffic accident when he was 77 years old. Radiography revealed extensive ossification of the bilateral patellar tendons. We review the English literature with a focus on the localization of bilateral heterotopic ossification of the knee in patients who had a central nervous system injury

Hip Fractures after Intramedullary Nailing Fixation for Atypical Femoral Fractures: Three Cases

Secondary hip fractures (SHFs) rarely occur after intramedullary nailing (IMN) fixation without femoral neck fixation for atypical femoral fractures (AFFs). We report three cases of older Japanese women who sustained SHFs presumably caused by osteoporosis and peri-implant stress concentration around the femoral neck after undergoing IMN without femoral neck fixation for AFF. All cases were fixed with malalignment. In AFF patients, postoperative changes due to postoperative femoral bone malalignment may affect the peri-implant mechanical environment around the femoral neck, which can result in insufficiency fractures. At the first AFF surgery, we recommend femoral neck fixation after adequate reduction is achieved

jaw osteonecrosis risk in hip fractures

Purpose : Antiresorptive agents, such as bisphosphonates, are useful for the prevention of the recurrence of hip fractures. However, their administration has a risk of antiresorptive agent-related osteonecrosis of the jaw (ARONJ), and risk factors include poor oral hygiene. It is difficult for an orthopedic surgeon to examine a patient’s oral condition thoroughly. This study evaluated the relationship between risk factors for ARONJ and intraoral findings in hip fracture patients. Materials and Methods : We evaluated 79 patients (average age of 82.2 years) with hip fracture surgery who underwent an oral assessment by dentists. The risk assessments of the intraoral findings were classified into four levels (levels 0-3), with levels 2 and 3 requiring dental treatment intervention. Data that could be extracted as risk factors of ARONJ were also examined. Results : Level 1 was found most frequently (54.4%), followed by level 0 (35.4%), level 2 (8.9%), level 3 (1.3%). The area under the receiver operating characteristic curve for the number of risk factors for the two groups (dental treatment intervention required and unnecessary) and oral findings were 0.732. When the cut-off value was set to two risk factors, the specificity and sensitivity was 53.5% and 87.5%. Conclusions : For hip fracture patients with a more than 2 risk factors, dental visits are recommended to prevent ARONJ. This is a useful evaluation method that can be used to screen for ONJ from data obtained from other risk factors, even if it is difficult to evaluate the oral condition in hospitals where dentists are absent

Aripiprazole augmentation to antidepressant therapy in Japanese patients with major depressive disorder: A randomized, double-blind, placebo-controlled study (ADMIRE study)

AbstractObjectiveThis randomized, placebo-controlled study evaluated the efficacy and safety of a fixed dose (3mg/day) and flexible dose (3–15mg/day) schedule of aripiprazole as augmentation therapy in Japanese patients with inadequate response to antidepressant therapy (ADT).MethodDuring an 8-week prospective treatment phase, patients experiencing a major depressive episode received clinicians' choice of ADT. Subjects with inadequate response to ADT were randomized to receive adjunctive treatment with placebo (n=195), fixed dose aripiprazole (n=197) or flexible dose aripiprazole (n=194) for 6 weeks. The primary efficacy endpoint was mean change in the Montgomery–Åsberg Depression Rating Scale (MADRS) total score from the end of prospective treatment (baseline) to the end of randomized treatment.ResultsMore than 90% of patients in all treatment groups completed the 6-week double-blind treatment phase. Mean MADRS total score was improved to a significantly greater extent with fixed dose aripiprazole and flexible dose aripiprazole (−10.5 and −9.6, respectively) than with placebo (−7.4). Aripiprazole was well tolerated. The incidence of akathisia observed in the flexible dose group may relate to a higher prevalence of the CYP2D6*10 allele in Asian populations.LimitationsSix weeks of adjunctive treatment is insufficient to draw conclusions about the long-term benefits of aripiprazole. Exclusion of patients with established medical comorbidities does not reflect real-world practice.ConclusionsAripiprazole augmentation at a fixed or flexible dose was superior to ADT alone and was reasonably well tolerated in Japanese patients with inadequate response to ADT.Clinical trials registrationClinicalTrials.gov identifier NCT00876343