Boosting computational power through spatial multiplexing in quantum reservoir computing

Quantum reservoir computing provides a framework for exploiting the natural dynamics of quantum systems as a computational resource. It can implement real-time signal processing and solve temporal machine learning problems in general, which requires memory and nonlinear mapping of the recent input stream using the quantum dynamics in computational supremacy region, where the classical simulation of the system is intractable. A nuclear magnetic resonance spin-ensemble system is one of the realistic candidates for such physical implementations, which is currently available in laboratories. In this paper, considering these realistic experimental constraints for implementing the framework, we introduce a scheme, which we call a spatial multiplexing technique, to effectively boost the computational power of the platform. This technique exploits disjoint dynamics, which originate from multiple different quantum systems driven by common input streams in parallel. Accordingly, unlike designing a single large quantum system to increase the number of qubits for computational nodes, it is possible to prepare a huge number of qubits from multiple but small quantum systems, which are operationally easy to handle in laboratory experiments. We numerically demonstrate the effectiveness of the technique using several benchmark tasks and quantitatively investigate its specifications, range of validity, and limitations in detail.Comment: 15 page

Hospital physicians perform five types of work duties in Japan: An observational study

BACKGROUND: Physicians are expected to perform three unique roles as a clinician, educator, and researcher in university hospitals. However, the actual practices of physicians performing different duties are relatively unknown. Therefore, the authors conducted an observational study at a university hospital to examine physicians’ work activities. METHODS: Between 2011 and 2013, ten observers shadowed 20 physicians from different specialties for a day at the Tokyo Women’s Medical University Hospital. Observers recorded physicians’ activities every 30 seconds that were subsequently categorized into work types. The number of work types and activity changes performed by a physician in one observational period were counted. RESULTS: Authors categorized physicians’ work activities into five groups: patient care (direct and indirect), education, research, professional development, and administration. All physicians performed at least one type of activity in addition to patient care. Activity change occurred 1.86 times per hour, on average. The median time-distribution of 20 physicians was 173.8 minutes, 213.8 minutes, 3.3 minutes, 5.0 minutes, 0 minutes, and 0.8 minutes for direct patient care, indirect patient care, education, research, professional development, and administration, respectively. CONCLUSION: Japanese hospital physicians performed multiple work duties including professional development and administrative activities in addition to triple duties. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1472-6963-14-375) contains supplementary material, which is available to authorized users

Novel Autologous Therapy for Long-Gap Peripheral Nerve Injury Using Human Sk-SCs

Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs) to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34) and CD34-/45-/29+ (Sk-DN/29+) cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm) bridging an acellular conduit. After 8-12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells) were also observed. A significant tetanic tension recovery (over 90%) of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap) was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon) and functional (80% vs. 60% in tetanus) recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks) of recovery was observed in both groups with the expression of key factors (mRNA and protein levels), suggesting the paracrine effects to angiogenesis. These results suggested that the human Sk-SCs may be a practical source for autologous stem cell therapy following severe peripheral nerve injury

FED surgery for L5 radiculopathy

In this report, we presented a 65 year-old male case having right leg pain due to L5 radiculopathy. Based on the radiological examination including CT, MRI and radiculography, double crash impingement of L5 nerve root due to L4-5 lateral recess and L5-S foraminal stenosis was diagnosed. Because of the strong pain, he could not work anymore. His job was a general manager of big hospital, he needed to return to job as soon as possible. We decided to conduct the full-endoscopic decompression surgery of ventral facetectomy (FEVF) for L4-5 lateral recess stenosis and foraminoplasty (FELF) for L5-S foraminal stenosis. The technique can be done under the local anesthesia with only 8 mm skin incision; thus, it must be the least invasive spine surgery. Soon after the surgery, he could return to the original job as a general manager. In conclusion, the full-endoscopic decompression surgery for the spinal canal stenosis such as FELF and FEVF would be minimally invasive procedure and it enable patients the quick return to the original activity

CHAC1 overexpression in human gastric parietal cells with Helicobacter pylori infection in the secretory canaliculi

Background Cation transport regulator 1 (CHAC1), a newly discovered enzyme that degrades glutathione, is induced in Helicobacter pylori (H. pylori)‐infected gastric epithelial cells in culture. The CHAC1‐induced decrease in glutathione leads to an accumulation of reactive oxygen species and somatic mutations in TP53. We evaluated the possible correlation between H. pylori infection and CHAC1 expression in human gastric mucosa. Materials and Methods Both fresh‐frozen and formalin‐fixed paraffin‐embedded tissue samples of gastric mucosa with or without H. pylori infection were obtained from 41 esophageal cancer patients that underwent esophago‐gastrectomy. Fresh samples were used for real‐time polymerase chain reaction for H. pylori DNA and CHAC1 mRNA, and formalin‐fixed samples were used for immunohistochemistry with anti‐CHAC1 and anti‐H. pylori monoclonal antibodies. Double‐enzyme or fluorescence immunohistochemistry and immuno‐electron microscopy were used for further analysis. Results Significant CHAC1 overexpression was detected in H. pylori‐infected parietal cells that expressed the human proton pump/H,K‐ATPase α subunit, whereas a constitutively low level of CHAC1 mRNA expression was observed in the other samples regardless of the H. pylori infection status, reflecting the weak CHAC1 expression detected by immunohistochemistry in the fundic‐gland areas. Immuno‐electron microscopy revealed intact H. pylori cells in the secretory canaliculi of infected parietal cells. Some parietal cells exhibited positive nuclear signals for Ki67 in the neck zone of the gastric fundic‐gland mucosa with H. pylori infection. Conclusion Cation transport regulator 1 overexpression in H. pylori‐infected parietal cells may cause the H. pylori‐induced somatic mutations that contribute to the development of gastric cancer.This work was supported by the Japan Society for the Promotion of Science KAKENHI (16K19077), and by the Practical Research for Innovative Cancer Control from Japan Agency for Medical Research and development, AMED