Memristive Switching Mechanism in Colloidal InP/ZnSe/ZnS Quantum Dot-Based Synaptic Devices for Neuromorphic Computing.

Quantum dots (QDs) have garnered a significant amount of attention as promising memristive materials owing to their size-dependent tunable bandgap, structural stability, and high level of applicability for neuromorphic computing. Despite these advantageous properties, the development of QD-based memristors has been hindered by challenges in understanding and adjusting the resistive switching (RS) behavior of QDs. Herein, we propose three types of InP/ZnSe/ZnS QD-based memristors to elucidate the RS mechanism, employing a thin poly(methyl methacrylate) layer. This approach not only allows us to identify which carriers (electron or hole) are trapped within the QD layer but also successfully demonstrates QD-based synaptic devices. Furthermore, to utilize the QD memristor as a synapse, long-term potentiation/depression (LTP/LTD) characteristics are measured, resulting in a low nonlinearity of LTP/LTD at 0.1/1. On the basis of the LTP/LTD characteristics, single-layer perceptron simulations were performed using the Extended Modified National Institute of Standards and Technology, verifying a maximum recognition rate of 91.46%.

Observation of electronic modes in open cavity resonator.

The resemblance between electrons and optical waves has strongly driven the advancement of mesoscopic physics, evidenced by the widespread use of terms such as fermion or electron optics. However, electron waves have yet to be understood in open cavity structures which have provided contemporary optics with rich insight towards non-Hermitian systems and complex interactions between resonance modes. Here, we report the realization of an open cavity resonator in a two-dimensional electronic system. We studied the resonant electron modes within the cavity and resolved the signatures of longitudinal and transverse quantization, showing that the modes are robust despite the cavity being highly coupled to the open background continuum. The transverse modes were investigated by applying a controlled deformation to the cavity, and their spatial distributions were further analyzed using magnetoconductance measurements and numerical simulation. These results lay the groundwork to exploring matter waves in the context of modern optical frameworks.

Development of three-dimensional canine hepatic tumor model based on computed tomographic angiography for simulation of transarterial embolization.

Introduction: Transarterial embolization (TAE) is one of the treatment options for liver masses that are not suitable for surgery and they have been applied in veterinary medicine for about 20 years, but surgical resection is considered as the first treatment option, and only a few case reports and articles about TAE in dogs have been published. Although understanding of vascular anatomy for the procedure is important, previous studies lack of the information about hepatic artery anatomy in small and toy-breed dogs. Due to the introduction of 3D print in veterinary medicine, it is now possible to make 3D models for preoperative planning. The purpose of this study is to understand the hepatic arterial vascular structure of various sizes and breeds of dogs, and to develop 3D-printed canine artery models with and without hepatic tumors to simulate TAE procedure. Methods: CT images of a total of 84 dogs with normal hepatic arteries were analyzed, and the mean value and standard deviation of body weight, celiac artery size, and hepatic artery size were 6.47 ± 4.44 kg, 3.28 ± 0.77 mm, and 2.14 ± 0.43 mm, respectively. Results: It was established that type 2-2-1, which has two separate hepatic branches-the right medial and left branch and the right lateral branch that runs to the right lateral lobe and caudate process-is the most prevalent of the hepatic artery branch types, as it was in the previous study. The review of 65 CT images of dogs with hepatic tumors showed that 44.6% (29/65) had multifocal lesions in multiple lobes, for which TAE can be recommended. Discussion: Based on the result, a 3D model of the normal canine hepatic artery and the hepatic tumor was made using one representative case from each group, and despite the models having some limitations in reflecting the exact tactile and velocity of blood vessels, TAE procedure was successfully simulated using both models.

Robust quantum point contact via trench gate modulation.

Quantum point contacts (QPC) are a primary component in mesoscopic physics and have come to serve various purposes in modern quantum devices. However, fabricating a QPC that operates robustly under extreme conditions, such as high bias or magnetic fields, still remains an important challenge. As a solution, we have analyzed the trench-gated QPC (t-QPC) that has a central gate in addition to the split-gate structure used in conventional QPCs (c-QPC). From simulation and modelling, we predicted that the t-QPC has larger and more even subband spacings over a wider range of transmission when compared to the c-QPC. After an experimental verification, the two QPCs were investigated in the quantum Hall regimes as well. At high fields, the maximally available conductance was achievable in the t-QPC due to the local carrier density modulation by the trench gate. Furthermore, the t-QPC presented less anomalies in its DC bias dependence, indicating a possible suppression of impurity effects.

Vertebral osteomyelitis caused by non-tuberculous mycobacteria: Predisposing conditions and clinical characteristics of six cases and a review of 63 cases in the literature.

Background Several case series have reported on clinical and radiographic characteristics of patients with vertebral osteomyelitis (VO) caused by non-tuberculous mycobacteria (NTM). However, only a few patients were included, and systematic reviews are still lacking. The aim of this study was to update and summarise the pre-disposing conditions, clinical and radiographic characteristics of such cases due to NTM. Methods In this study, a systematic review was conducted of the English-language literature from 1961-2014 to investigate the pre-disposing conditions and characteristics of cases of VO due to NTM. Also, six additional cases diagnosed in the study hospitals were described; these cases are included in an analysis of a total of 69 cases of NTM VO. Results The most common species, regardless of the presence of HIV co-infection, was M. avium Complex followed by M. xenopi. Ten cases with HIV infection had a median CD4 lymphocyte count of 320/mm(3) (range = 41-465/mm(3)) at the time of diagnosis of NTM VO. The VO in the cases with HIV infections occurred at an earlier age and more often involved the thoracic spine than in the cases without HIV infection. Pre-disposing trauma or surgery was reported in 14.5% (10/69) of the cases. A variety of immunosuppressive diseases were observed in 49.3% of the patients, including the 10 with HIV infections and corticosteroids were used in 27.5% of the cases. Surgery was performed in 67.6% and improvement was reported in 80.6%. Conclusion NTM should be considered in immunocompromised patients with indolent VO without confirmation of tuberculosis.

Clinical Risk Factors for Upper Gastrointestinal Bleeding after Percutaneous Coronary Intervention: A Single-Center Study.

BACKGROUND/AIMS: Percutaneous coronary intervention (PCI) is often performed therapeutically, and antithrombotic treatment is required for at least 12 months after stent implantation. However, the development of post-PCI upper gastrointestinal bleeding (UGIB) increases morbidity and mortality. We investigated the incidence and risk factors for UGIB in Korean patients within 1 year after PCI. METHODS: The medical records of 3,541 patients who had undergone PCI between January 2006 and June 2012 were retrospectively reviewed. We identified 40 cases of UGIB. We analyzed the incidence and clinical risk factors associated with UGIB occurring within 1 year after PCI by comparing the results for each case to matched controls. The propensity score matching method using age and sex was utilized. RESULTS: UGIB occurred in 40 patients (1.1%). Two independent risk factors for UGIB were a history of peptic ulcer disease (odds ratio [OR], 12.68; 95% confidence interval [CI], 2.70 to 59.66; p=0.001) and the use of anticoagulants (OR, 7.76; 95% CI, 2.10 to 28.66; p=0.002). CONCLUSIONS: UGIB after PCI occurred at a rate of 1.1% in the study population. Clinicians must remain vigilant for the possibility of UGIB after PCI and should consider performing timely endoscopy in patients who have undergone PCI and are suspected of having an UGIB.

Inappropriateness of quinolone in scrub typhus treatment due to gyrA mutation in Orientia tsutsugamushi Boryong strain.

The use of quinolone for treatment of rickettsial diseases remains controversial. Recent clinical studies suggest that quinolone is not as effective as others in patients with rickettsial diseases including scrub typhus, although the mechanism is not well understood. In this study, we evaluated the mutation in gyrA associated with quinolone resistance. We prospectively enrolled scrub typhus patients, collected blood samples and clinical data from October, 2010 to November, 2011. Among the 21 patients enrolled, one initially received ciprofloxacin for 3 days but was switched to doxycycline due to clinical deterioration. We obtained the gyrA gene of Orientia tsutsugamushi from 21 samples (20 Boryong strain, 1 Kato strain) and sequenced the quinolone resistance-determining region. All of 21 samples had the Ser83Leu mutation in the gyrA gene, which is known to be associated with quinolone resistance. This suggests that quinolones may be avoided for the treatment of serious scrub typhus.

Clinical prognostic factors for locally advanced esophageal squamous carcinoma treated after definitive chemoradiotherapy.

PURPOSE: Locally advanced esophageal cancers are generally treated with neoadjuvant chemoradiotherapy, followed by surgery in operable candidates. However, even if the patients were diagnosed as operable disease, surgery could not be performed on patients with poor condition or other comorbidity. In this case, definitive chemoradiotherapy (dCRT) is the other option for localized esophageal cancer. Therefore, the purpose of this study was to evaluate the efficacy and clinical prognostic factors for dCRT in locally advanced esophageal cancer. MATERIALS AND METHODS: We conducted a review of patients who received dCRT for locally advanced squamous esophageal cancer from 2004 to 2010, focusing on stages III and IVa. All patients received at least two cycles of platinum-based chemotherapy during radiation, and all tumor burdens were included in the radiation field. The treatment results were analyzed for patterns of failure and prognostic factors associated with survival. RESULTS: In total, 63 patients were enrolled in this study. The overall response rate was 84.1%. Relief from dysphagia after dCRT was achieved in 48 patients. The most frequent failure was local recurrence. The median overall survival (OS) was 23.0 months, and the 2-year survival rate was 45.4%. Similar results were observed for elderly study patients. Significant prognostic factors for OS were duration of smoking, high grade of dysphagia (score of 3 or 4), and shorter duration of progression-free and dysphagia-free survival. Maintenance chemotherapy after dCRT did not influence OS. However, "good risk" patients receiving maintenance chemotherapy showed better OS than those who did not receive maintenance chemotherapy (30.4 months vs. 12.0 months, p=0.002). CONCLUSION: dCRT has a major role in improving survival and palliation of dysphagia in inoperable advanced esophageal cancer, even in elderly patients. Maintenance chemotherapy after dCRT may be effective in prolonging survival in "good risk" patients.