Neuromorphic System Using Memcapacitors and Autonomous Local Learning.

Artificial intelligence is used for various applications and is promising as an indispensable infrastructure in future societies. Neural networks are representative technologies that imitate human brains and exhibit various advantages. However, the size is bulky, the power is huge, and some advantages are not demonstrated because they are executed on Neumann-type computers. Neuromorphic systems are biomimetic systems from the hardware level to implement neuron and synapse elements, and the size is compact, the power is low, and the operation is robust. However, because the conventional ones are not composed of fully optimized hardware, the power is not yet minimal, and extra control circuits must be used. In this article, we developed a neuromorphic system using memcapacitors and autonomous local learning. By using memcapacitors, the power can be minimal, and by using autonomous local learning, the control circuits to handle the synapse elements can be deleted. First, the memcapacitors are completed in a cross-bar array, where the ferroelectric layers are sandwiched between the horizontal and perpendicular electrodes. The polarization and capacitance exhibit hysteresis due to the dielectric polarization. Next, autonomous local learning is introduced as follows. During the training phase, associative patterns to be memorized are directly sent, relatively high voltages are applied, and dielectric polarizations are induced. During the operation phase, relatively low voltages are applied, and input signals are weighted with the capacitances of the memcapacitors, summed, and transferred as the output signals. Finally, the experimental system is set up, and the experimental results are acquired. The memorized patterns during the training phase, distorted patterns as the input signals during the operation phase, and retrieved patterns as the output signals in the operation phase are shown. Researchers found that the retrieved patterns are completely the same as the memorized patterns. This means that the neuromorphic system works as an associative memory.

Miniaturization of Respiratory Measurement System in Artificial Ventilator for Small Animal Experiments to Reduce Dead Space and Its Application to Lung Elasticity Evaluation.

A respiratory measurement system composed of pressure and airflow sensors was introduced to precisely control the respiratory condition during animal experiments. The flow sensor was a hot-wire thermal airflow meter with a directional detection and airflow temperature change compensation function based on MEMS technology, and the pressure sensor was a commercially available one also produced by MEMS. The artificial dead space in the system was minimized to the value of 0.11 mL by integrating the two sensors on the same plate (26.0 mm × 15.0 mm). A balloon made of a silicone resin with a hardness of A30 was utilized as the simulated lung system and applied to the elasticity evaluation of the respiratory system in a living rat. The inside of the respiratory system was normally pressurized without damage, and we confirmed that the developed system was able to evaluate the elasticity of the lung tissue in the rat by using the pressure value obtained at the quasi-static conditions in the case of the ventilation in the animal experiments.

Effects of Transplanted Human Cord Blood-Mononuclear Cells on Pulmonary Hypertension in Immunodeficient Mice and Their Distribution.

OBJECTIVES: To investigate the effects of human umbilical cord blood-derived mononuclear cell (hUCB-MNC) transplantation on pulmonary hypertension (PH) induced by monocrotaline (MCT) in immunodeficient mice and their distribution. METHODS: MCT was administered to BALB/c Slc-nu/nu mice, and PH was induced in mice 4 weeks later. Fresh hUCB-MNCs harvested from a human donor after her delivery were injected intravenously into those PH mice. The medial thickness of pulmonary arterioles, ratio of right ventricular to septum plus left ventricular weight (RV/S+LV), and ratio of acceleration time to ejection time of pulmonary blood flow waveform (AT/ET) were determined 4 weeks after hUCB-MNC transplantation. To reveal the incorporation into the lung, CMTMR-labeled hUCB-MNCs were observed in the lung by fluorescent microscopy. DiR-labeled hUCB-MNCs were detected in the lung and other organs by bioluminescence images. RESULTS: Medial thickness, RV/S+LV and AT/ET were significantly improved 4 weeks after hUCB-MNC transplantation compared with those in mice without hUCB-MNC transplantation. CMTMR-positive hUCB-MNCs were observed in the lung 3 hours after transplantation. Bioluminescence signals were detected more strongly in the lung than in other organs for 24 hours after transplantation. CONCLUSIONS: The results indicate that hUCB-MNCs are incorporated into the lung early after hUCB-MNC transplantation and improve MCT-induced PH. J. Med. Invest. 64: 43-49, February, 2017.

[Experience of Mitral Valve Replacement Using a Pulmonary Autograft (Ross II Operation) in an Infant;Report of a Case].

A 24-day-old boy suddenly developed progressive heart failure and was transported to our hospital. Echocardiography showed massive mitral regurgitation due to chordal rupture. Mitral valve repair was performed at 28 days of life, but postoperative valvular function was not satisfactory. A mechanical valve was implanted in the supra-annular position at 37 days of life. Two months after valve replacement, the mechanical valve was suddenly stuck. Emergent redo valve replacement was performed, but the prosthetic valve became stuck again 2 months after the 3rd operation, despite sufficient anti-coagulation therapy. At the 4th operation (6 months after birth), we implanted a pulmonary autograft in the mitral position instead of another mechanical valve in an emergent operation. The right ventricular outflow tract was reconstructed with a valved conduit. A postoperative catheter examination, which was performed 1 year after the Ross II operation, showed mild mitral stenosis with no regurgitation. Previous reports of Ross II operations in infants are rare and long-term results are unknown. However, we advocate that this procedure should be a rescue operation for mitral valve dysfunction in the early period of infants.

[Experience of 3 successfully treated cases of tracheo-innominate artery fistula and significance of preventive surgery].

Tracheo-innominate artery fistula (TIF) is a rare but fatal complication after tracheostomy. Necessary lifesaving measures include proper ventilation, temporary hemostasis, and surgery. Recently, we successfully managed 3 cases of TIF. Ventilation and temporary hemostasis were secured by a long endotracheal tube and overinflated cuff. Division of the innominate artery, restoration of the tracheal fistula with an autologous pericardial patch or direct closure, and aorto-innominate bypass grafting or extra-anatomical bypass grafting with a polytetrafluoroethylene (PTFE) graft were performed through an emergency median sternotomy. All 3 patients recovered with no problems. After TIF occurs, the patient's condition rapidly worsens, and the risk of bacterial contamination in the operative field may increase. Surgical intervention should be performed for patients with tracheal stenosis who are judged to be at high risk for TIF. This preventive surgery includes bypass grafting to divide the innominate artery and partial resection of the anterior bony thorax(upper sternum, medial part of clavicles, and anterior part of upper ribs if necessary). We believe that this procedure will improve tracheal stenosis and minimize the risk of TIF. Thus far, 10 patients have undergone this operation, and their mid-term results are satisfactory.

A novel Doppler echocardiographic score reflecting cardiac functional status can predict adverse outcome in acute myocardial infarction.

BACKGROUND: E/e' and s' are thought to reflect left ventricular diastolic and systolic function, respectively. However, there are no reports on the combined use of E/e' and s' in predicting the outcome in acute myocardial infarction (AMI). METHODS: For 20 months beginning in October 2006, we enrolled 65 AMI patients who had undergone Swan-Ganz (SG) catheterization and echocardiography just after reperfusion therapy. We measured the cardiac index (CI) and the pulmonary capillary wedge pressure (PCWP) via an SG catheter and determined routine echocardiographic indices, including transmitral flow velocity (E), mitral annulus velocities at systole (s') and early diastole (e'), and E/e'. In addition, we rounded off the values of s' (cm/s) and E/e' (ratio of cm/s to cm/s) to the nearest integer, and designated them the s'-score and E/e'-score, respectively. We also defined the cardiac status score as the s'-score subtracted from the E/e'-score. In Study 1, we investigated the relationships between hemodynamic parameters (CI and PCWP) and echocardiographic indices, including the cardiac status score. In Study 2, we excluded patients with Killip class ≥II, yielding a final study population of 55 patients in whom we investigated whether the cardiac status score could predict adverse cardiac events. RESULTS: Only the cardiac status score significantly correlated with both the PCWP and the CI. In the Cox proportional hazards model, significant predictors were the left ventricular ejection fraction (LVEF), estimated glomerular filtration rate (eGFR), and cardiac score ≥3.0. CONCLUSIONS: The novel score achieved in this study by subtracting the s'-score from the E/e'-score could be highly useful for predicting outcomes in AMI with Killip class I.

Successful early resection of cardiac papillary fibroelastomas.

Two adult patients with previous transient cerebral ischemic attacks (TIAs) or chest oppression were referred for further investigation. A swaying pedicled tumor was detected in the left atrium of the former patient and in the left coronary cusp of the latter by echocardiography. The TIA, or angina-like attack, was anticipated to be caused by thromboembolism of the tumor. Both patients underwent tumor extirpation. The histological findings demonstrated that both tumors were benign papillary fibroelastoma limited to the endocardium/endothelium layer. In conclusion, early surgical resection of a cardiac papillary fibroelastoma should be performed.

Syngeneic bone marrow mononuclear cells improve pulmonary arterial hypertension through vascular endothelial growth factor upregulation.

BACKGROUND: We investigated the effects and possible mechanism of syngeneic bone marrow mononuclear cell (BM-MNC) transplantation on pulmonary arterial hypertension induced by monocrotaline. METHODS: Monocrotaline (80 mg/kg body weight) was administrated to C57BL/6 mice, and pulmonary arterial hypertension was induced 4 weeks later. Bone marrow mononuclear cells harvested from syngeneic donor mice were injected intravenously into those mice 4 weeks after monocrotaline administration. The ratio of right ventricular to septum plus left ventricular weight, the number of small pulmonary arteries, and medial thickness of pulmonary arteries were measured. Western immunoblotting of the lung tissue was performed to observe vascular endothelial growth factor and its receptor expression 1 week after BM-MNC transplantation. Vascular endothelial growth factor receptor-2 inhibitor was administered to pulmonary arterial hypertension mice simultaneously with BM-MNC transplantation. RESULTS: The ratio of right ventricular to septum plus left ventricular weight increased, the number of pulmonary arteries decreased, and medial thickness increased significantly 4 weeks after monocrotaline injection compared with those of vehicle-injected mice. These indices of monocrotaline-injected mice improved significantly 4 weeks after BM-MNC transplantation compared with those of mice at 8 weeks after monocrotaline injection (0.22 +/- 0.02 versus 0.31 +/- 0.02; 17.1 +/- 2.6 versus 8.2 +/- 1.7; 7.7% +/- 2.2% versus 20% +/- 2.1%, respectively; p < 0.01). However, BM-MNCs were not incorporated into the lung at 1 week after transplantation, and significant vascular endothelial growth factor upregulation and without receptor expression was observed in lung tissue 1 week after transplantation. Improvement of pulmonary arterial hypertension was inhibited by simultaneous administration of vascular endothelial growth factor receptor-2 inhibitor with BM-MNC transplantation. CONCLUSIONS: These results indicate that syngeneic BM-MNC transplantation improves monocrotaline-induced pulmonary arterial hypertension by favorable pulmonary artery remodeling through vascular endothelial growth factor upregulation.

Significance of peritoneal fluid drainage in management after repair of complex heart defects in infancy: cytokine dynamics in vivo.

BACKGROUND: In vivo redundancy of pro-inflammatory cytokines results in a vicious cycle of systemic inflammatory response syndrome and low cardiac output syndrome (LOS). The purpose of this study was to elucidate the influence of peritoneal fluid (PF) drainage on cytokine dynamics in vivo and the significance of early induction for infants with LOS. METHODS AND RESULTS: Seven infants, who underwent early PF drainage to manage LOS after repair of complex heart defects under cardiopulmonary bypass, were enrolled. The serum and PF levels of the pro- and antiinflammatory cytokines, interleukin (IL)-6, -8, -10 and tumor necrosis factor (TNF)-alpha, were measured during the perioperative period. Clinical outcomes were observed simultaneously. There were no cases of early or late death, or infectious complications. Drainage volume of PF peaked just after operation, and decreased completely. The amount of proinflammatory cytokines in the PF increased for 3 days after operation. Of the proinflammatory cytokines in the PF IL-6 increased the earliest and cleared the fastest. The amount of cleared IL-8 and TNF-alpha peaked on the 3rd postoperative day and resembled the course of C-reactive protein (CRP). Serum levels of CRP and proinflammatory cytokines in patients with PF drainage decreased significantly more than those without PF drainage. CONCLUSIONS: Early initiation of PF drainage is useful in the postoperative critical care of infants with LOS by improving cytokine dynamics in vivo, although there are differences between the severity of patients undergoing PF drainage and those who do not.