産卵鶏卵巣の自然免疫システムにおけるサイトカインと抗菌ペプチドの役割に関する研究

広島大学(Hiroshima University)博士(学術)Doctor of Philosophydoctora

Three-phase ac-dc buck-boost converter with a reduced number of switches

A single-switch, single-stage, three-phase ac-dc buck-boost converter suitable for medium-voltage applications is proposed. Basic relations that govern steady-state converter operation are established, confirmed using PSCAD/EMTDC simulations, and substantiated experimentally. Simulation and experimental results establish that the proposed converter has good dynamic performance in buck and boost modes, with near unity input power factor

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Current source based wind energy conversion system

This thesis considers the use of a full-scale back-to-back pulse width modulated current source converter (BTB-PWM-CSC) as an interfacing converter for a variable-speed wind energy conversion system (WECS) that uses a permanent magnet synchronous generator (PMSG). It has been shown that the proposed current source converter based WECS can operate successfully under maximum power point tracking and meet all grid requirements such as ac fault ride-through and power quality aspects at the point of common coupling. This thesis presents three different CSC based WECSs. The first WECS is based on a back-to-back dual pulse width modulated current source converter (BTB-DPWM-CSC) as an interface for a dual three-phase PMSG, with two stator windings, shifted by 30°. Both the generator and grid side dual PWM rectifier and inverters (CSR and CSI) of the WECS are controlled using selective harmonic elimination (SHE) for low semiconductor loss operation. The grid side CSI is connected to the ac grid through a three-winding phase-shift transformer to benefit from cancellation of the low-order harmonics in the primary winding, which is connected to the ac grid side. The secondary and tertiary windings, which are connected to the upper and lower halves of the dual PWM-CSI, are delta and wye connected; thus, SHE is only needed to eliminate the 11th and 13th harmonics. The SHE modulation employed to control both the dual PWM-CSR and CSI has one unique pattern, which is characterised by continuous pulse angle changes and a fixed switching frequency over the full modulation index range. These attributes show that the proposed BTB-DPWM-CSC WECS is suited for multi-megawatt applications. The second and third WECSs are based on modified three-phase and dual three-phase BTB-PWM-CSCs. These configurations are developed to address the main drawbacks of the conventional CSC employed in the first proposal, such as transient over-voltages experienced by the converter switches during commutation and semiconductor loss reduction. The latter is achieved by using a dedicated high frequency synchronization method that ensures zero current switching at the CSI terminal; thus, nearly zero switching loss is achieved. The proposed WECSs offer the following additional advantages: reduced power circuit and control complexity; reduced switching frequency; applicable to fixed and variable frequency operation, hence, allowing maximum power point tracking with independent control of active and reactive powers delivered to the ac grid; and low-voltage ride-through capability. Viability of the proposed WECSs are assessed using simulations performed in PSCAD/EMTDC and confirmed experimental, with results from scaled down prototypes, assessed in steady-state and dynamically under different operating conditions. It is shown that continuous and discontinuous operation of the second and third configurations provide trade-offs between overall weight and size of the WECS and high current and voltage stresses in the semiconductor switches.This thesis considers the use of a full-scale back-to-back pulse width modulated current source converter (BTB-PWM-CSC) as an interfacing converter for a variable-speed wind energy conversion system (WECS) that uses a permanent magnet synchronous generator (PMSG). It has been shown that the proposed current source converter based WECS can operate successfully under maximum power point tracking and meet all grid requirements such as ac fault ride-through and power quality aspects at the point of common coupling. This thesis presents three different CSC based WECSs. The first WECS is based on a back-to-back dual pulse width modulated current source converter (BTB-DPWM-CSC) as an interface for a dual three-phase PMSG, with two stator windings, shifted by 30°. Both the generator and grid side dual PWM rectifier and inverters (CSR and CSI) of the WECS are controlled using selective harmonic elimination (SHE) for low semiconductor loss operation. The grid side CSI is connected to the ac grid through a three-winding phase-shift transformer to benefit from cancellation of the low-order harmonics in the primary winding, which is connected to the ac grid side. The secondary and tertiary windings, which are connected to the upper and lower halves of the dual PWM-CSI, are delta and wye connected; thus, SHE is only needed to eliminate the 11th and 13th harmonics. The SHE modulation employed to control both the dual PWM-CSR and CSI has one unique pattern, which is characterised by continuous pulse angle changes and a fixed switching frequency over the full modulation index range. These attributes show that the proposed BTB-DPWM-CSC WECS is suited for multi-megawatt applications. The second and third WECSs are based on modified three-phase and dual three-phase BTB-PWM-CSCs. These configurations are developed to address the main drawbacks of the conventional CSC employed in the first proposal, such as transient over-voltages experienced by the converter switches during commutation and semiconductor loss reduction. The latter is achieved by using a dedicated high frequency synchronization method that ensures zero current switching at the CSI terminal; thus, nearly zero switching loss is achieved. The proposed WECSs offer the following additional advantages: reduced power circuit and control complexity; reduced switching frequency; applicable to fixed and variable frequency operation, hence, allowing maximum power point tracking with independent control of active and reactive powers delivered to the ac grid; and low-voltage ride-through capability. Viability of the proposed WECSs are assessed using simulations performed in PSCAD/EMTDC and confirmed experimental, with results from scaled down prototypes, assessed in steady-state and dynamically under different operating conditions. It is shown that continuous and discontinuous operation of the second and third configurations provide trade-offs between overall weight and size of the WECS and high current and voltage stresses in the semiconductor switches

Assessment of a wind energy conversion system based on a six-phase permanent magnet synchronous generator with a twelve-pulse PWM current source converter

The steady-state and dynamic performances of a new high-power variable speed wind-energy conversion system (WECS) that uses a six-phase permanent magnet synchronous generator (PMSG) with twelve-pulse back-to-back pulse width modulated current source converters is assessed. The proposed WECS inherently has all the features of existing systems based on voltage source converters, such as voltage control and fault ride-through capability, but with increased reliability and improved ac side waveform quality, benefiting from the three-winding phase shifting transformer for further attenuation of the low-order harmonics. PSCAD/EMTDC simulation is used to assess the steady-state and dynamic behaviours of the proposed system under different operating conditions. Experimental results, obtained using a prototype grid side dual current source inverter (CSI), are presented to validate the proposed technique

Public Security Surveillance System Using Blockchain Technology and Advanced Image Processing Techniques

National security is a top priority to mitigate intrusions and criminal acts. Governments require robust national surveillance system that can cover all geographical areas, including the blind spots that may hold violence and criminal incidents' triggers i.e. malls, stadiums, airports, and other key sites. Integrating existing surveillance infrastructures rather than creating centralized solutions will have great potential on scalability as well as providing more liberal framework that is not run by a single point of control. However, this definitely requires establishing secure communication and mutual trust amongst these entities, which is a real challenge. Towards this end, we propose an efficient smart surveillance architecture that combines machine learning and Blockchain technologies to facilitate the exchange of relevant surveillance events as admitted transactions into a permissioned Hyperledger fabric Blockchain. We conducted comprehensive analysis to demonstrate the feasibility of blockchain and the efficiency of the machine learning-based face recognition and matching for real-time surveillance of suspects using heterogeneous surveillance infrastructure. The proposed architecture proved scalability and real-time behavior after putting the system through multiple test cases. With very high matching accuracy, and end-to-end latency of less than 12.8 seconds, the system proves to be scalable, and fast enough for a smart surveillance use case. 2020 IEEE.Scopu

Parietin Cyclodextrin-Inclusion Complex as an Effective Formulation for Bacterial Photoinactivation

Multidrug resistance in pathogenic bacteria has become a significant public health concern. As an alternative therapeutic option, antimicrobial photodynamic therapy (aPDT) can successfully eradicate antibiotic-resistant bacteria with a lower probability of developing resistance or systemic toxicity commonly associated with the standard antibiotic treatment. Parietin (PTN), also termed physcion, a natural anthraquinone, is a promising photosensitizer somewhat underrepresented in aPDT because of its poor water solubility and potential to aggregate in the biological environment. This study investigated whether the complexation of PTN with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) could increase its solubility, enhance its photophysical properties, and improve its phototoxicity against bacteria. At first, the solubilization behavior and complexation constant of the PTN/HP-β-CD inclusion complexes were evaluated by the phase solubility method. Then, the formation and physicochemical properties of PTN/HP-β-CD complexes were analyzed and confirmed in various ways. At the same time, the photodynamic activity was assessed by the uric acid method. The blue light-mediated photodegradation of PTN in its free and complexed forms were compared. Complexation of PTN increased the aqueous solubility 28-fold and the photostability compared to free PTN. PTN/HP-β-CD complexes reduce the bacterial viability of Staphylococcus saprophyticus and Escherichia coli by > 4.8 log and > 1.0 log after irradiation, respectively. Overall, the low solubility, aggregation potential, and photoinstability of PTN were overcome by its complexation in HP-β-CD, potentially opening up new opportunities for treating infections caused by multidrug-resistant bacteria

Comparative study between the trachlight and SensaScope intubation in normal patients scheduled for elective surgery

Introduction: Airway management is a core stone and remains a challenge of every anesthetist. Visual control may facilitate tracheal intubation. Rigid video-laryngoscopes are emerging among the devices suggested as alternatives to direct laryngoscopy. Among the many alternative devices to choose for tracheal intubation, semi-rigid fibrescopes and lighted stylets can alternate rigid laryngoscopy in endotracheal intubation. Aim of the work: The aim of the study was to clarify the efficacy and hemodynamic responses associated with tracheal intubation using trachlight technique (blind object) compared to SensaScope technique in patients subjected to elective surgery. Patients and methods: Thirty patients were randomly allocated to either the trachlight (TL) or SensaScope (SS) group, (15 patients in each group). All endotracheal intubations were performed after induction of general anesthesia. Evaluation of technique, performance, duration of intubation, number of attempts at intubation, success rate of intubation with each device, hemodynamic changes [heart rate (HR), mean arterial blood pressure (MAP)] and oxygen saturation (SpO2) were recorded. Results: The duration of the intubation procedures was shorter in the SS group (64.86 ± 54.166 s) than in the TL group (68.53 ± 50.89 s) but without statistical significance, while no significant difference in the numbers of intubation attempts between the two groups. HR and MAP showed transient increase without statistical significance between both groups. Conclusion: The endotracheal intubation was effectively using either trachlight or SensaScope, while the SensaScope (SS) group showed shorter time and attenuation of the hemodynamic changes produced by tracheal intubation without significant postoperative complications except 13% complaining of hoarseness of voice after extubation