•Appelmans protocol broadens host range of a phage cocktail targeting acinetobacter baumannii.•Prophage induction and recombination contributes to the broadening of the phage cocktail host ...range.•Recombination of prophages from encountered bacterial strains generates expanded host range phages.•Induced phages demonstrated limited stability, unsuitable for therapy.
Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) present significant healthcare challenges due to limited treatment options. Bacteriophage (phage) therapy offers potential as an alternative treatment. However, the high host specificity of phages poses challenges for their therapeutic application. To broaden the phage spectrum, laboratory-based phage training using the Appelmans protocol was employed in this study. As a result, the protocol successfully expanded the host range of a phage cocktail targeting CRAB. Further analysis revealed that the expanded host range phages isolated from the output cocktail were identified as recombinant derivatives originating from prophages induced from encountered bacterial strains. These findings provide valuable genetic insights into the protocol's mechanism when applied to phages infecting A. baumannii strains that have never been investigated before. However, it is noteworthy that the expanded host range phages obtained from this protocol exhibited limited stability, raising concerns about their suitability for therapeutic purposes.
In this study, we aimed to design a novel and effective bacteriophage cocktail that can target both wild-type bacteria and phage-resistant mutants. To achieve this goal, we isolated four phages ...(U2874, phi_KPN_H2, phi_KPN_S3, and phi_KPN_HS3) that recognized different bacterial surface molecules using phage-resistant bacteria. We constructed three phage cocktails and tested their phage resistance-suppressing ability against multidrug-resistant Klebsiella pneumoniae. We argue that the phage cocktail that induces resensitization of phage susceptibility exhibited superior phage resistance-suppressing ability. Moreover, we observed trade-off effects that manifested progressively in phage-resistant bacteria. We hypothesize that such trade-off effects can augment therapeutic efficacy. We also recommend collating phage host range data against phage-resistant mutants in addition to wild-type bacteria when establishing phage banks to improve the efficiency of phage therapy. Our study underscores the importance of phage host range data in constructing effective phage cocktails for clinical use.
The sliding mode controller has characteristics that ensure stability and robustness against system uncertainty and disturbance.
However, chattering occurs in the control inputs to compensate for ...system uncertainties and ensure that the system operates efficiently on the sliding surface. When the disturbance is large, using a sliding mode controller requires a large control gain value, which also increases chattering and reduces performance. Therefore, in this study, a nonlinear disturbance observer was used to compensate for external disturbances such as currents and waves and uncertainty in the control system for autonomous underwater vehicles. Accordingly, a robust controller can be implemented while reducing the control gain. The disturbance observer serves to ensure that the behavior of the actual system is closer to the nominal model by compensating for uncertainties between the actual system model and the nominal model during the control process. Therefore, the simulation results show that the performance and robustness of the autonomous underwater vehicle controller are improved by introducing a disturbance observer. KCI Citation Count: 0
Electrical metal contacts to two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) are found to be the key bottleneck to the realization of high device performance due to ...strong Fermi level pinning and high contact resistances (R c). Until now, Fermi level pinning of monolayer TMDCs has been reported only theoretically, although that of bulk TMDCs has been reported experimentally. Here, we report the experimental study on Fermi level pinning of monolayer MoS2 and MoTe2 by interpreting the thermionic emission results. We also quantitatively compared our results with the theoretical simulation results of the monolayer structure as well as the experimental results of the bulk structure. We measured the pinning factor S to be 0.11 and −0.07 for monolayer MoS2 and MoTe2, respectively, suggesting a much stronger Fermi level pinning effect, a Schottky barrier height (SBH) lower than that by theoretical prediction, and interestingly similar pinning energy levels between monolayer and bulk MoS2. Our results further imply that metal work functions have very little influence on contact properties of 2D-material-based devices. Moreover, we found that R c is exponentially proportional to SBH, and these processing parameters can be controlled sensitively upon chemical doping into the 2D materials. These findings provide a practical guideline for depinning Fermi level at the 2D interfaces so that polarity control of TMDC-based semiconductors can be achieved efficiently.
Ultrasound B-mode imaging provides anatomical images of the body with a high resolution and frame rate. Recently, to improve its flexibility, most ultrasound signal and image processing modules in ...modern ultrasound B-mode imaging systems have been implemented in software. In a software-based B-mode imaging system, an efficient processing technique for calculating a logarithm instruction is required to support its high computational burden. In this paper, we present a new method to efficiently implement a logarithm operation based on exponent bit extraction. In the proposed method, the exponent bit field is first extracted and then some algebraic operations are applied to improve its precision. To evaluate the performance of the proposed method, the peak signal-to-noise ratio (PSNR) and the execution time were measured. The proposed efficient logarithm operation method substantially reduced the execution time, i.e., eight times, compared to direct computation while providing a PSNR of over 50 dB. These results indicate that the proposed efficient logarithm computation method can be used for lowering the computational burden in software-based ultrasound B-mode ultrasound imaging systems while improving or maintaining the image quality.
Thermally activated delayed fluorescence (TADF) is beneficial for improving the efficiency of organic light‐emitting diodes (OLEDs) by providing pathways to convert non‐emissive triplet excitons into ...singlet excitons. To ensure TADF is efficient, it is critical to enhance the reverse intersystem crossing (RISC) rate. To this end, most approaches propose thus far have focused on reducing the energy difference between S1 and T1 states. The present study explores how incorporating the internal heavy atom (IHA) effect can impact the RISC and device performance. By introducing a series of halogen atoms to charge‐transfer molecules, TADF molecules exhibiting RISC over 7 × 107 s−1 are realized. These molecules are then applied to OLEDs, and the effect of incorporating these moieties is investigated. The results show that efficiency roll‐off is still significant even with RISC‐enhanced TADF emitters. Spectroscopic and theoretical results indicate that a fast RISC may not be the sole factor important for reducing efficiency roll‐off and that the spin‐flip cycles considering both T1→S1 and S1→T1 should be carefully taken into account to derive a complete picture of the IHA effect on efficiency roll‐off behavior.
This study explores how incorporating the internal heavy atom (IHA) effect can impact the reverse intersystem crossing (RISC) and device performance. The spectroscopic and theoretical results indicate that a fast RISC may not be the sole factor important for reducing efficiency roll‐off and that the spin‐flip cycles should be carefully considered to derive a complete picture of the IHA effect.
•A new adaptive beamformer based on unsupervised deep learning approach, i.e., deep coherence learning (DCL), is proposed for high-quality single plane wave (PW) ultrasound imaging.•The DCL leads the ...deep learning model to predict highly correlated signals from multiple PWs and it encourages high-image quality PW imaging from low-quality single PW data.•The DCL framework based on complex baseband signals enables a universal ultrasound beamformer.
Plane wave imaging (PWI) in medical ultrasound is becoming an important reconstruction method with high frame rates and new clinical applications. Recently, single PWI based on deep learning (DL) has been studied to overcome lowered frame rates of traditional PWI with multiple PW transmissions. However, due to the lack of appropriate ground truth images, DL-based PWI still remains challenging for performance improvements. To address this issue, in this paper, we propose a new unsupervised learning approach, i.e., deep coherence learning (DCL)-based DL beamformer (DL-DCL), for high-quality single PWI. In DL-DCL, the DL network is trained to predict highly correlated signals with a unique loss function from a set of PW data, and the trained DL model encourages high-quality PWI from low-quality single PW data. In addition, the DL-DCL framework based on complex baseband signals enables a universal beamformer. To assess the performance of DL-DCL, simulation, phantom and in vivo studies were conducted with public datasets, and it was compared with traditional beamformers (i.e., DAS with 75-PWs and DMAS with 1-PW) and other DL-based methods (i.e., supervised learning approach with 1-PW and generative adversarial network (GAN) with 1-PW). From the experiments, the proposed DL-DCL showed comparable results with DMAS with 1-PW and DAS with 75-PWs in spatial resolution, and it outperformed all comparison methods in contrast resolution. These results demonstrated that the proposed unsupervised learning approach can address the inherent limitations of traditional PWIs based on DL, and it also showed great potential in clinical settings with minimal artifacts.
Synapses in the brain utilize two distinct communication mechanisms: chemical and electrical. For a comprehensive investigation of neural circuitry, neural interfaces should be capable of both ...monitoring and stimulating these types of physiological interactions. However, previously developed interfaces for neurotransmitter monitoring have been limited in interaction modality due to constraints in device size, fabrication techniques, and the usage of flexible materials. To address this obstacle, we propose a multifunctional and flexible fiber probe fabricated through the microwire codrawing thermal drawing process, which enables the high-density integration of functional components with various materials such as polymers, metals, and carbon fibers. The fiber enables real-time monitoring of transient dopamine release in vivo, real-time stimulation of cell-specific neuronal populations via optogenetic stimulation, single-unit electrophysiology of individual neurons localized to the tip of the neural probe, and chemical stimulation via drug delivery. This fiber will improve the accessibility and functionality of bidirectional interrogation of neurochemical mechanisms in implantable neural probes.
Despite several years of research into graphene electronics, sufficient on/off current ratio / on // off in graphene transistors with conventional device structures has been impossible to obtain. We ...report on a three-terminal active device, a graphene variable-barrier "barristor" (GB), in which the key is an atomically sharp interface between graphene and hydrogenated silicon. Large modulation on the device current (on/off ratio of 10⁵) is achieved by adjusting the gate voltage to control the graphene-silicon Schottky barrier. The absence of Fermi-level pinning at the interface allows the barrier's height to be tuned to 0.2 electron volt by adjusting graphene's work function, which results in large shifts of diode threshold voltages. Fabricating GBs on respective 150-mm wafers and combining complementary p-and n-type GBs, we demonstrate inverter and half-adder logic circuits.
