Additional Switching Research Articles

Phenotypic Switching and Filamentation in Candida haemulonii, an Emerging Opportunistic Pathogen of Humans.

ABSTRACTPhenotypic plasticity is a common strategy adopted by fungal pathogens to adapt to diverse host environments. Candida haemulonii is an emerging multidrug-resistant human pathogen that is closely related to Candida auris. Until recently, it was assumed that C. haemulonii is incapable of phenotypic switching or filamentous growth. In this study, we report the identification of three distinct phenotypes in C. haemulonii: white, pink, and filament. The white and pink phenotypes differ in cellular size, colony morphology, and coloration on phloxine B- or CuSO4-containing agar. Switching between the white and pink cell types is heritable and reversible and is referred to as “the primary switching system.” The additional switch phenotype, filament, has been identified and exhibits obviously filamentous morphology when grown on glycerol-containing medium. Several unique characteristics of the filamentous phenotype suggest that switching from or to this phenotype poses as a second yeast-filament switching system. The yeast-filament switch is nonheritable and temperature-dependent. Low temperatures favor the filamentous phenotype, whereas high temperatures promote filament-yeast transition. We further demonstrated that numerous aspects of the distinct cell types differ in numerous biological aspects, including their high temperature response, specific gene expression, CuSO4 tolerance, secreted aspartyl protease (SAP) activity, and virulence. Therefore, transition among the three phenotypes could enable C. haemulonii to rapidly adapt to, survive, and thrive in certain host niches, thereby contributing to its virulence.IMPORTANCE The capacity to switch between distinct cell types, known as phenotypic switching, is a common strategy adopted by Candida species to adapt to diverse environments. Despite considerable studies on phenotypic plasticity of various Candida species, Candida haemulonii is considered to be incapable of phenotypic switching or filamentous growth. Here, we report and describe filamentation and three distinct phenotypes (white, pink, and filament) in C. haemulonii. The three cell types differ in cellular and colony appearance, gene expression profiles, CuSO4 tolerance, and virulence. C. haemulonii cells switch heritably and reversibly between white and pink cell types, which is referred to as the “primary switching system.” Switching between pink and filamentous phenotypes is nonheritable and temperature-dependent, representing a second switching system. As in other Candida species, switching among distinct morphological types may provide C. haemulonii with phenotypic plasticity for rapid responses to the changing host environment, and may contribute to its virulence.

A Novel Fully Controllable Rotary Switch for Electrical Installation in Buildings

In an electrical installation in buildings, electromechanical switches are mostly used to turn on and off a load. However, sometimes there are two or more switches in the same circuit intended to control the same load. Thus, a conflict can happen between multi-users who are trying to overtake the control of the load (such as turning it on or off). To solve the problem, this paper proposes a novel switch called “Fully Controllable Rotary Switch” (FCRS) in which it can fully control not only the load but also other switches by blocking them or giving them limited or full access over the electrical circuit and the loads. For validation purposes, the utilization of FCRS in buildings is compared to the traditional switches under the same functionality and conditions. Results show that FCRS has the ability to control many electrical loads simultaneously, control other switches in the circuit, increase the satisfaction, security, and privacy of the users. Finally, it reduces the conflict between multi-users and the investment cost by avoiding installing additional switches and protection devices.

A NOVEL FULLY CONTROLLABLE ROTARY SWITCH FOR ELECTRICAL INSTALLATION IN BUILDINGS

In an electrical installation in buildings, electromechanical switches are mostly used to turn on and off a load. However, sometimes there are two or more switches in the same circuit intended to control the same load. Thus, a conflict can happen between multi-users who are trying to overtake the control of the load (such as turning it on or off). To solve the problem, this paper proposes a novel switch called “Fully Controllable Rotary Switch” (FCRS) in which it can fully control not only the load but also other switches by blocking them or giving them limited or full access over the electrical circuit and the loads. For validation purposes, the utilization of FCRS in buildings is compared to the traditional switches under the same functionality and conditions. Results show that FCRS has the ability to control many electrical loads simultaneously, control other switches in the circuit, increase the satisfaction, security, and privacy of the users. Finally, it reduces the conflict between multi-users and the investment cost by avoiding installing additional switches and protection devices.

Optimized Modulation Method for Common-Mode Voltage Reduction in H7 Inverter

The three-phase H7 inverter topology installs an additional power semiconductor switch to the positive or negative node of the DC-link for reducing the common-mode voltage (CMV) by disconnecting the inverter from the DC source during the zero-voltage vectors. The conventional CMV reduction method for the three-phase H7 inverter uses modified discontinuous pulse width modulation (MDPWM) and generates a switching signal for the additional switch using logical operations. However, the conventional method is unable to eliminate the CMV for the entire dwell time of the zero-voltage vectors. It only has the effect of reducing the CMV in a limited area of the space vector where the V7 zero voltage vector is applied. Therefore, this paper proposes an optimized modulation method that can reduce the CMV during the entire dwell time of zero-voltage vectors. The proposed method moves the switching patterns by adding an offset voltage to guarantee that only one kind of zero-voltage vector, V7, is applied in the system. It then turns off the seventh switch only during the zero-voltage vector to disconnect the inverter from the DC source. As a result, the CMV and the leakage current are attenuated for the entire dwell time of the zero-voltage vector. Simulation and experimental results confirm the validity of the proposed method.

Safety, Immunogenicity and Interchangeability of Biosimilar Monoclonal Antibodies and Fusion Proteins: A Regulatory Perspective.

BackgroundBiosimilars have been used for 15 years in the European Union (EU), and have been shown to reduce costs and increase access to important biological medicines. In spite of their considerable exposure and excellent safety record, many prescribers still have doubts on the safety and interchangeability of biosimilars, especially monoclonal antibodies (mAbs) and fusion proteins.ObjectivesThe aim of this study was to analyse the short- and long-term safety and interchangeability data of biosimilar mAbs and fusion proteins to provide unbiased information to prescribers and policy makers.MethodsData on the safety, immunogenicity and interchangeability of EU-licensed mAbs and fusion proteins were examined using European Public Assessment Reports (EPARs) and postmarketing safety surveillance reports from the European Medicines Agency (EMA). As recent biosimilar approvals allow self-administration by patients by the subcutaneous route, the administration devices were also analyzed.ResultsPrelicensing data of EPARs (six different biosimilar adalimumabs, three infliximabs, three etanercepts, three rituximabs, two bevacizumabs, and six trastuzumabs) revealed that the frequency of fatal treatment-emergent adverse events (TEAEs), TEAEs leading to discontinuation of treatment, serious adverse events (SAEs), and main immune-mediated adverse events (AEs) were comparable between the biosimilars and their reference products. The availability of new biosimilar presentations and administration devices may add to patient choice and be an emerging factor in the decision to switch patients. Analysis of postmarketing surveillance data covering up to 7 years of follow-up did not reveal any biosimilar-specific adverse effects. No product was withdrawn for safety reasons. This is in spite of considerable exposure to biosimilars in treatment-naïve patients and in patients switched from the reference medicinal product to the biosimilar. Analysis of data from switching studies provided in regulatory submissions showed that single or multiple switches between the originator and its biosimilar versions had no negative impact on efficacy, safety or immunogenicity.ConclusionsIn line with previous reports of prelicensing studies of biosimilar mAbs and etanercepts, this study demonstrated comparable efficacy, safety, and immunogenicity compared with the reference products. This is the first study to comprehensively analyze postmarketing surveillance data of the biosimilar mAbs and etanercept. An analysis of more than 1 million patient-treatment years of safety data raised no safety concerns. Based on these data, we argue that biosimilars approved in the EU are highly similar to and interchangeable with their reference products. Thus, additional systematic switch studies are not required to support the switching of patients.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40265-021-01601-2.

Soft-Switching Mechanism for a High-Gain, Interleaved Hybrid Boost Converter

In this article, an auxiliary circuit-based soft-switching mechanism for a high-gain, nonisolated, four-phase interleaved hybrid boost converter is presented. The auxiliary circuit consists of only a single additional switch, four diodes, and a small auxiliary inductor, and ensures zero voltage transition (ZVT) of all four phases. Two variations of the ZVT circuit application are presented in this article, each having its own advantages and can be implemented without any significant modifications in the auxiliary circuit. The auxiliary switch operates with zero current switching, ensuring that the power loss in the auxiliary circuit is low for both cases. The timing of the ZVT circuit is adaptively controlled with changing load conditions. The proposed concepts are validated through a 2.5 kW hardware prototype operating at 100 kHz and achieving a high gain conversion from 46 V input to 850-V output. The converter is able to achieve a peak efficiency of 98.3% with silicon devices as main switches at 100-kHz switching frequency.

Simulation of Different Third Harmonic Injected PWM Strategies for 5-Level Diode-Clamped Multilevel Inverter

Multilevel Inverters (MLI) have widespread use in industrial drive applications, HVDC transmission with Uninterruptable Power Supply systems. They also have applications in the stand-alone and the grid connected renewable energy systems. Multi-level Inverters also find optimum application in Stand-alone and Grid-connected Systems. Majority of losses i.e. switching losses are considered with constrained device rating, the traditional two-level inverters face limits especially when operating at high frequency. The solution which is optimum and appropriate by many power quality researchers is the use of MLIs. Among various MLI topologies the Diode-Clamped Multilevel Inverter (DCMLI) give a promising solution as they can give better voltage performance for different switching frequencies and an improved total harmonic distortion (THD) profile without the use of filter. To meet the voltage and frequency requirement various modulation techniques are applied to MLIs. The additional switching states created by these topologies provide greater flexibility to control more circuit breakers. This paper presents the comparison of a 5-level DCMLIs with several modulation schemes. The simulation results are discussed in detail and the comparison table is presented in terms of Output voltage and THD.

Effect of COVID-19 pandemic on the treatment process and adherence to treatment of the patients receiving allergen-specific immunotherapy

Aim: During the COVID-19 pandemic, the number of hospital admissions has significantly decreased, due to both the risk of transmission and the restrictions imposed. The most adversely affected ones are patients who need to admit to a hospital due to their chronic diseases, such as those receiving allergen im-munotherapy. Material and Methods: Files of the patients who were administered subcutaneous immunotherapy (SCIT) regularly, were retrospectively reviewed. At first outpatient clinic visits during the period of so-called normalization process (June-July-August 2020), the patients were asked to fill a mini questionnaire and validated coronavirus anxiety questionnaire. Results: A total of 151 patients receiving SCIT were included in the study. The most common government-related factors hindering outpatient clinic visits of the patients were travel restrictions (40.6%) and the most common patient-related factors were fear of contracting SARS-CoV-2 (39.7%). Overall adherence to treatment during the 3-month period from March to April-May 2020 was determined to be 54.3%. The duration of immunotherapy, increased allergic symptoms, the need for additional treatment and treatment switch in SCIT because of the pandemic were significantly higher in patients non-adherent to SCIT treatment compared to adherent ones (p: 0.031, p: 0.001, p: 0.001 and p: 0.001, respectively). Discussion: Access to allergen immunotherapy, applicability, and maintenance of the immunotherapy should be a priority during the COVID-19 pandemic. Considering both patient-related and government-related factors in the administration of immunotherapy, the process of immunotherapy should be continued, minimizing the risk of SARS-CoV-2 transmission. Furthermore, patients’ worry and anxiety levels may be reduced with these measures and their adherence to treatment may be promoted.

Control system for a frequency synchronized asynchronous electric drive

THE PURPOSE. In controlled AC drives used on continuous-action mechanisms, which include conveyors, conveyors, cranes, the most widespread are asynchronous motors with a phase rotor, controlled mainly along the rotor circuit using various regulators with low energy efficiency. To improve the energy efficiency of an electric drive based on ADFR, it is proposed to develop a control system that combines the principles of frequency control of the motor along the stator circuit and powering the rotor circuit with constant voltage, which allows the electric drive to be considered synchronized. METHODS. The presence of a DC link in the frequency converter makes it possible in principle to connect the rotor winding in series to this link. However, in order to ensure the frequency principle of regulating the output characteristics of the electric drive, it will be necessary to regulate the rectified current at the input of the inverter and, accordingly, in the rotor windings, which will require a significant change in the standard control system of the frequency converter. The use of an additional adjustable switch in the DC link is proposed. RESULTS. The study of the proposed non-standard control system for a frequency asynchronous synchronized electric drive was carried out by the method of simulation modeling in the Matlab Simulink software package. CONCLUSION. A control system for a frequency asynchronous synchronized electric drive has been developed and investigated on a computer model. A correction system is proposed that allows maintaining a constant value of the load angle in the starting mode. The scalar system of relay frequency control of the electric drive is supplemented with vector correction of the variables, which makes it possible to continuously provide the necessary mutual orientation of the stator current vectors and the rotor flux linkage.

Control system for a frequency synchronized asynchronous electric drive

THE PURPOSE. In controlled AC drives used on continuous-action mechanisms, which include conveyors, conveyors, cranes, the most widespread are asynchronous motors with a phase rotor, controlled mainly along the rotor circuit using various regulators with low energy efficiency. To improve the energy efficiency of an electric drive based on ADFR, it is proposed to develop a control system that combines the principles of frequency control of the motor along the stator circuit and powering the rotor circuit with constant voltage, which allows the electric drive to be considered synchronized. METHODS. The presence of a DC link in the frequency converter makes it possible in principle to connect the rotor winding in series to this link. However, in order to ensure the frequency principle of regulating the output characteristics of the electric drive, it will be necessary to regulate the rectified current at the input of the inverter and, accordingly, in the rotor windings, which will require a significant change in the standard control system of the frequency converter. The use of an additional adjustable switch in the DC link is proposed. RESULTS. The study of the proposed non-standard control system for a frequency asynchronous synchronized electric drive was carried out by the method of simulation modeling in the Matlab Simulink software package. CONCLUSION. A control system for a frequency asynchronous synchronized electric drive has been developed and investigated on a computer model. A correction system is proposed that allows maintaining a constant value of the load angle in the starting mode. The scalar system of relay frequency control of the electric drive is supplemented with vector correction of the variables, which makes it possible to continuously provide the necessary mutual orientation of the stator current vectors and the rotor flux linkage.

Hierarchical Electrode Switching Device Design for Distributed Single-Channel Electrical Resistivity Tomography System

An electrode switching device (ESD) is one of the most important components of electrical resistivity tomography (ERT). It is a ligament and relay between a testing circuit and testing electrodes. Existing ESD uses a plane structure to realize the interconnection between ports and testing electrodes. Taking Wenner testing as an example, each electrode needs four additional switches. In this report, a new hardware saving ESD (HESD) is made with a hierarchical structure for a single-channel distributed ERT. HESD has two-layered switches to realize the conversion process. The first layer of 16 switches can realize four pairs of unrepeated connection between four ports—AMNB and four Lines—L1–L4. The second layer establishes the non-overlapping joints between four lines—L1–L4 and four testing electrodes. Each electrode only needs one switch for an 1D test, which has been wildly used in soil science, ocean probing, and contaminated surveys, and an odd number layer test. With the newly designed HESD, three fourths of the cost of hardware (switch) was saved compared with the conventional ESD. In addition, with two more switches, HESD was able to complete a 2D survey. The new two-layer HESD saves hardware costs and shows advantages in maintenance, system tests, and miniaturization, especially when many electrodes are required in an ERT system, which is very common in practice.

An Intrinsically Switched Tunable CABW/CFBW Bandpass Filter

In this paper, a novel intrinsically switched tunable bandpass filter based on a dual-mode T-shaped varactor-loaded resonator is presented. The varactors loaded in the T-shaped resonator are capable of efficiently tuning the resonant frequencies of the even and odd modes, as well as the transmission-zero frequency. Without any additional RF switches, the passband of the filter can be intrinsically switched off by adjusting the transmission zero to the resonant frequencies. In the switch-on state, the constant absolute bandwidth (CABW) or constant fractional bandwidth (CFBW) passband can be achieved by controlling the frequency space between the two resonances. For a demonstration, a 0.8–1.1 GHz intrinsically switched tunable bandpass filter with 74 MHz CABW or 8.5% CFBW was fabricated and tested. In the whole operating band with |S11| < 10 dB, the insertion losses for CABW and CFBW are better than 3.3 dB and 3 dB, respectively, and the isolations are better than 20 dB in the switch-off state. The measured results have a good agreement with simulated results, which verifies the design theory.

Z-source converter integrated dc electric spring for power quality improvement in dc microgrid

Increasing penetration of renewable energy sources reveals the concept of dc microgrid which has the advantages of low cost and low losses because of the elimination of the AC/DC conversion processes. The most frequently encountered power quality problem in DC microgrid is voltage fluctuations due to the intermittent nature of renewable energy sources. Direct current (DC) electric spring (DCES), which is an emerging power quality device in DC microgrids, is employed in order to mitigate the effect of the related problem. In this paper, z source converter integrated DCES topology (zDCES) is proposed to provide a wide compensation voltage range with lower duty cycle range and a remarkable decrease in the battery nominal voltage in comparison with conventional systems. The proposed system composed of full-bridge converter, z source converter and battery pack. zDCES provides high voltage gain by using z source converter with passive components without any need for additional switches. The shoot-through control, which is used to achieve high gain in z source converter, is implemented using existing full-bridge switches. The performance of the proposed system is compared with the traditional DCES system. The performance of the zDCES is validated with a case study with different voltage fluctuation states.

Thermal switching requirements for solid state magnetic refrigeration

Magnetic refrigeration, based on the magnetocaloric effect, is an attractive alternative to the conventional vapor-compression technology. In a solid state magnetic refrigerator the traditional alternated fluid flow is replaced by two solid thermal switches (TSs) that control the heat flux. These TSs are materials, or devices, whose thermal conductivity changes with an external stimulus. Here, we numerically investigate how the performance of a solid state magnetic refrigerator depends on the TS thermal conductivities (k) and corresponding k-variations (Δk) with the magnetic field. Two different scenarios were considered: a single TS and a double TS magnetic refrigerator. We have numerically varied the thermal conductivity of the thermal switches, operating frequency and working temperature. The use of only one thermal switch with near-ideal Δk is enough if the required performance does not overcome half of the adiabatic temperature change (ΔTad) of the magnetocaloric material. To overcome this value the device must use two effective thermal switches. Using an additional thermal switch is only beneficial when ΔTad needs to be overcome, or when the first thermal switch shows a modest Δk. These results simplify the operability control, which will increase the interest for magnetically activated thermal switches operating at acceptable magnetic fields.

Probabilistic switching can solve the problem of costly prosocial exclusion

Public Goods Game (PGG) originates from “the Tragedy of Commons”, which is argued by the American scholar Hardin. PGG is a type of evolution game that these individuals in this game can affect each other, and reached a stable state. This paper demonstrates a new version PGG model which is an exclusion PGG model. Besides, combing Parrondo’s Paradox with this PGG model, and it also shows a similar “winning” outcome. Parrondo’s Paradox shows that two individual-losing games, when alternate, yield a winning outcome. Moreover, the additional periodic switching mechanism also applies to the PGG model and obtains a similar result when compared with that of conventional Parrondo’s Paradox. The biggest contribution of this paper is that Parrondo’s Paradox can fully applicable to the exclusion PGG model, and that simulation result also presents an effective result.

GaN-Based Multiple Output Flyback Converter With Independently Controlled Outputs

Several techniques are proposed in the literature to improve the cross-regulation performance of a multiple output flyback converter (MOFC). However, some drawbacks exist, first, inability to completely eliminate cross-regulation, second, reduction of power density due to a high number of additional components, third, increased losses. To overcome these challenges, this article presents a scheme to independently control the outputs of an MOFC, thereby achieving an excellent cross-regulation performance over a wide range of loads, without any additional switching or magnetic component. The unique gate dependent reverse conduction characteristics of gallium nitride (GaN) high electron mobility transistor is utilized to control the flow of current to each of the output capacitors. The operational principle and the steady-state analysis are provided in detail. Moreover, design considerations, such as the switching frequency, GaN gate bias, leakage inductances, and output capacitance, are discussed, focusing on their impacts on the key design goals, particularly the efficiency, power density, and output voltage ripple. Furthermore, SPICE simulations are used to demonstrate the improvement in cross-regulation over existing schemes. Finally, a 40 W dual output laboratory prototype is built to verify the analysis. The measured maximum cross-regulation is 0.2%, which validates the effectiveness of the scheme.

A Novel High-Power-Factor Electrolytic-Capacitorless LED Driver Based on Ripple Port

In this article, a novel high-power-factor electrolytic-capacitorless light-emitting diode (LED) driver based on the use of a ripple port is presented. The ripple port consists of adding an extra power processing circuit at the output of the converter that injects energy to compensate for the output current and voltage ripples. In this work, the main converter is built by using a flyback converter operating in the discontinuous conduction mode (DCM). The ripple port is implemented by adding an extra winding to the flyback coupled inductors, together with an extra switch, a capacitor, and an inductor. The additional switch is used to inject energy to the output in the time intervals, in which the flyback output current is low, thus reducing the output current ripple. The proposed converter is analyzed in detail, and a design methodology is proposed. A design example for a 27-V/1-A LED lamp is presented. Simulation and laboratory experiments have also been carried out. It is demonstrated that the proposed solution can achieve a reduction on the output current ripple of around 65% compared to the solution without ripple port for the same total capacitance and maintain a high power factor of 0.994.

H ∞ bipartite consensus of nonlinear multi-agent systems over a directed signed graph with a leader of non-zero input

This paper examines the bipartite tracking consensus for nonlinear multi-agents over a directed signed graph under bounded disturbances and a non-zero bounded input of the leader. For dealing with disturbances, the control theory has been adopted to develop a robust bipartite tracking consensus protocol. An additional switching control action is proposed to counteract the bounded matching input of the leader. The proposed control ensures the asymptotic convergence of the consensus error for known matching bounded input at the leader without disturbances, and an performance criterion from bounded disturbances to the consensus error has been provided. Contrary to the traditional consensus frameworks, our approach considers the nonlinear agents to resolve the bipartite consensus, disturbances for a robust distributed control, directed signed graphs, and bounded non-zero input at the leader for dealing with a realistic consensus scenario. Two simulation examples are provided for illustration.

Cueing effects of colour on attention management in multiple-view visualisations: evidence from eye-tracking by using a dual-task paradigm

ABSTRACT Multiple-view visualisation leads to additional switching cost on attention management between viewports. In this study, we compare the cueing effect of chromatic and achromatic colours on mitigating viewport switching cost in multiple-view visualisations through the dual-task paradigm. There is a concurrent need for managing attention within and between viewports, and performing a three single-digit mental addition task, which poses challenge for the capacity-limited working memory (WM). Response time and total fixation count support the benefit of chromatic colours in within-viewport attention management. First-pass progressive fixation time reveals that chromatic colours lead to better coherence within the viewport than achromatic colours, and there exist a correction process for attention misguidance in invalid cueing conditions. We employed re-visitation count and duration as direct measures of WM reinstatement. Fewer re-visitation count and shorter duration in the valid chromatic cueing condition indicate that more WM resources were freed up for the primary task, and reduced resources were depleted on overcoming the viewport switching cost. The positive role of valid chromatic colour cues become increasingly evident when more viewports presented simultaneously. The study provides eye movement evidence that chromatic cues can effectively lessen the switching cost on attention management in multiple-view visualisations.

Nonlinear vibrations of beams with bilinear hysteresis at supports: interpretation of experimental results

Experimental vibration responses of beams with nonlinear boundary conditions were interpreted using a bilinear spring model. Two systems of beams were considered: one is a single rod and the second one is a cluster of parallel rods linked together. The boundary conditions at the beam ends, for both systems, were provided by spacer grids, which are specific supports used in nuclear industry. The experiments were conducted with the beams immersed in still water. The nonlinear boundary conditions imposed to the beams by the spacer grids were experimentally characterized. The boundary conditions changed from having a rotational linear stiffness at low vibration amplitudes to bilinear with hysteresis at higher vibration amplitudes. The bilinear stiffness was found to be of the softening type. A bilinear stiffness model with viscous damping was used to interpret the forced vibration response of the beams. The stiffness and damping ratio used in the model were identified at any excitation level by minimizing, in the frequency domain, the weighted distance between the set of experimental points and the corresponding numerical results. The equivalent viscous damping of the system grew with the vibration amplitude. Very good agreement between numerical and experimental results was obtained for both the beam systems studied in the frequency and force-displacement domains. The model was further refined by using a piecewise linear stiffness function with additional switching points and introducing nonlinear damping. The identified model was capable of reproducing the experimental results with accuracy and without the requirement to adjust the parameters at different excitation levels.