Evolving spectrum of adenosine deaminase (ADA) deficiency: Assessing genotype pathogenicity according to expressed ADA activity of 46 variants.

BACKGROUND: Deficiency of adenosine deaminase (ADA or ADA1) has broad clinical and genetic heterogeneity. Screening techniques can identify asymptomatic infants whose phenotype and prognosis are indeterminate, and who may carry ADA variants of unknown significance. OBJECTIVE: We systematically assessed the pathogenic potential of rare ADA missense variants to better define the relationship of genotype to red blood cell (RBC) total deoxyadenosine nucleotide (dAXP) content and to phenotype. METHODS: We expressed 46 ADA missense variants in the ADA-deficient SØ3834 strain of Escherichia coli and defined genotype categories (GCs) ranked I to IV by increasing expressed ADA activity. We assessed relationships among GC rank, RBC dAXP, and phenotype in 58 reference patients with 50 different genotypes. We used our GC ranking system to benchmark AlphaMissense for predicting variant pathogenicity, and we used a minigene assay to identify exonic splicing variants in ADA exon 9. RESULTS: The 46 missense variants expressed ∼0.001% to ∼70% of wild-type ADA activity (40% had <0.05% of wild-type ADA activity and 50% expressed >1%). RBC dAXP ranged from undetectable to >75% of total adenine nucleotides and correlated well with phenotype. Both RBC dAXP and clinical severity were inversely related to total ADA activity expressed by both inherited variants. Our GC scoring system performed better than AlphaMissense in assessing variant pathogenicity, particularly for less deleterious variants. CONCLUSION: For ADA deficiency, pathogenicity is a continuum and conditional, depending on the total ADA activity contributed by both inherited variants as indicated by GC rank. However, in patients with indeterminate phenotype identified by screening, RBC dAXP measured at diagnosis may have greater prognostic value than GC rank.

Characterization and applicability of novel alkali-tolerant carbonatogenic bacteria as environment-friendly bioconsolidants for management of concrete structures and soil erosion.

Cracking and erosion are critical factors that reduce the mechanical properties and stability of concrete structures and soil, respectively. They are recognized worldwide as severe disasters causing the collapse of many structures including stone heritage and dams, and landslides. Therefore, it is essential to propose effective and environment-friendly management methods to prevent them. Carbonatogenesis has recently received considerable attention as a reliable biological process for remediating cracks in calcareous structures, stabilizing loose soils, and sequestering CO2 in the environment. Isolating and characterizing carbonatogenic bacteria with excellent performance is crucial for applying this process to the field of environmental and civil engineering. The aim of this study was to isolate new CaCO3-precipitating bacteria and investigate various properties for their use as bioconsolidants. Furthermore, the possibility of restoring damaged structures and stabilizing loose sandy soil using isolated strain was investigated. Strain LC13 with urease and CaCO3-precipitating activity was isolated from limestone cave soil in Korea and identified as Arthrobacter sulfureus by phenotypic characterization and 16S rRNA gene analysis. Although cell growth was observed after an adaptation period at pH 11, strain LC13 grew well at pH 7-11, indicating alkali tolerance. The optimal conditions for CaCO3 precipitation were 1.0% yeast extract, 2.5% urea, 0.35% NaHCO3, and 400 mM CaCl2, with an initial pH of 6.5 at 30 °C. Under optimized conditions, maximal CaCO3 (22.92 ± 0.14 g/l) precipitated after 3 days, which was 10.8-fold higher than the value in a urea-CaCl2 medium. CaCO3 precipitation by strain LC13 was associated with an increased pH due to ureolysis and protein deamination. Using an optimized medium as a cementation solution, strain LC13 completely remediated 340-760 µm wide cracks over 3 days, and also restored the spalling of concrete surfaces. Furthermore, the sand treated with LC13 solidified with a surface strength of 14.9 kPa. Instrumental analysis confirmed that the crystals precipitated were a mixture of CaCO3 polymorphs composed of rhombohedral calcite and spherical vaterite. These results suggest that A. sulfureus LC13 may be useful for implementing sustainable biorestoration and environmental management technologies such as the in situ remediation of structural cracks and in situ prevention of soil erosion.

Empagliflozin improved systolic blood pressure, endothelial dysfunction and heart remodeling in the metabolic syndrome ZSF1 rat.

BACKGROUND: Empagliflozin (empa), a selective sodium-glucose cotransporter (SGLT)2 inhibitor, reduced cardiovascular mortality and hospitalization for heart failure in patients with type 2 diabetes at high cardiovascular risk independent of glycemic control. The cardiovascular protective effect of empa was evaluated in an experimental model of metabolic syndrome, the obese ZSF1 rat, and its' lean control. METHODS: Lean and obese ZSF1 rats were either non-treated or treated with empa (30 mg/kg/day) for 6 weeks. Vascular reactivity was assessed using mesenteric artery rings, systolic blood pressure by tail-cuff sphygmomanometry, heart function and structural changes by echocardiography, and protein expression levels by Western blot analysis. RESULTS: Empa treatment reduced blood glucose levels from 275 to 196 mg/dl in obese ZSF1 rats whereas normoglycemia (134 mg/dl) was present in control lean ZSF1 rats and was unaffected by empa. Obese ZSF1 rats showed increased systolic blood pressure, and blunted endothelium-dependent relaxations associated with the appearance of endothelium-dependent contractile responses (EDCFs) compared to control lean rats. These effects were prevented by the empa treatment. Obese ZSF1 rats showed increased weight of the heart and of the left ventricle volume without the presence of diastolic or systolic dysfunction, which were improved by the empa treatment. An increased expression level of senescence markers (p53, p21, p16), tissue factor, VCAM-1, SGLT1 and SGLT2 and a down-regulation of eNOS were observed in the aortic inner curvature compared to the outer one in the control lean rats, which were prevented by the empa treatment. In the obese ZSF1 rats, no such effects were observed. The empa treatment reduced the increased body weight and weight of lungs, spleen, liver and perirenal fat, hyperglycemia and the increased levels of total cholesterol and triglycerides in obese ZSF1 rats, and increased blood ketone levels and urinary glucose excretion in control lean and obese ZSF1 rats. CONCLUSION: Empa reduced glucose levels by 28% and improved both endothelial function and cardiac remodeling in the obese ZSF1 rat. Empa also reduced the increased expression level of senescence, and atherothrombotic markers at arterial sites at risk in the control lean, but not obese, ZSF1 rat.

Effect of nitrogen-doping on drain current modulation characteristics of an indium-gallium-zinc oxide thin-film transistor.

The effect of nitrogen-doping (N-doping) in an indium-gallium-zinc oxide (IGZO) channel layer on the analog, linear, and reversible drain current modulation in thin-film transistors (TFTs) with Al-top-gate/SiOx/TaOx/IGZO stack is investigated for potential application to artificial synaptic devices. The N-doped devices exhibit a more linear increase of drain current upon repeating positive gate biasing, corresponding to synaptic potentiation, while the undoped device shows a highly non-linear and abrupt increase of drain current. Distinct from the increase of drain current at positive biasing for potentiation, the decrease of drain current for depression behavior at negative biasing is found to be the same. Whereas the increase of drain current becomes more linear, the channel conductance, the magnitude of its change, and its changing speed are decreased by the N-doping. The partial replacement of oxygen with nitrogen, having higher binding energy with metal-cations, suppresses oxygen vacancy formation, then decreases the channel conductance. It also retards the migration of oxygen ions, then leads to a linear increase of drain current. These results reveal that the characteristics of tunable drain current such as its linearity, dynamic range, and speed could be controlled by altering the internal state of the IGZO channel, which is crucial for application to an artificial synapse in a neuromorphic system.

Laser Light Therapy in Inflammatory, Musculoskeletal, and Autoimmune Disease.

PURPOSE OF REVIEW: The goal of this review is to summarize the field to date and to discuss strengths and limitations of low-level laser (light) therapy (LLLT) for the future investigation as a treatment of inflammatory disease. RECENT FINDINGS: LLLT is a promising therapeutic, particularly for those diseases of skin and joints because they are most accessible to treatment. Indeed, the known mechanisms of LLLT support its use for anti-inflammatory purposes, as well as stimulation of tissue growth and repair. Although the standard of care for the majority of inflammatory diseases is immunosuppressive agents such as corticosteroids with undesirable toxicities, LLLT offers a unique approach by being non-invasive and incurring minimal side effects. It is also relatively inexpensive and accessible and even has the possibility to be patient directed at home. There is evidence that LLLT is able to modulate the immune system at the skin and joint, and it has been shown to be efficacious in humans by affecting bacterial colonization as it may pertain to chronic rhinosinusitis. However, there is variability in the methods of laser application as well as a lack of evidence for laser type, dose-ranging studies, and wavelength selection that create barriers to the implementation of LLLT without further more rigorous and standardized study. The heterogeneity makes it difficult to draw strong conclusions about the efficacy of LLLT and its mechanisms.

Single- and double-gate synaptic transistor with TaO x gate insulator and IGZO channel layer.

We demonstrate single- and double-gate synaptic operations of a thin-film transistor (TFT) with double-gate stack consisting of an Al-top-gate/SiO x /TaO x /n-IGZO on a SiO2/n+-Si-bottom-gate substrate. This synaptic TFT exhibits a tunable drain current, mimicking synaptic weight modulation in the biological synapse, upon repeatedly applying gate and drain voltages. The drain current modulation features are analog, voltage-polarity dependently reversible, and strong with a dynamic range of multiple orders of magnitude (∼104). These features occur as a consequence of the changes in mobility of the IGZO channel, gate insulator capacitance, and threshold voltage. The drain current modulation responsive to the timing of the voltage application emulates synaptic potentiation, depression, paired-pulse facilitation, and memory transition behaviors depending on the voltage pulse amplitude, width, repetition number, and interval between pulses. The synaptic motions can be realized also by a double-gate operation that separately tunes the channel conductance by top-gate biasing and senses it by bottom-gate biasing. It provides the modulated synaptic weight with a wide level of synaptic weight through the read condition using a bottom-gate stack without read-disturbance. These results verify the potential application of TaO x /IGZO TFT with single- and double-gate operations to artificial synaptic devices.

A Smart Recommender Based on Hybrid Learning Methods for Personal Well-Being Services.

The main focus of the paper is to propose a smart recommender system based on the methods of hybrid learning for personal well-being services, called a smart recommender system of hybrid learning (SRHL). The essential health factor is considered to be personal lifestyle, with the help of a critical examination of various disciplines. Integrating the recommender system effectively contributes to the prevention of disease, and it also leads to a reduction in treatment cost, which contributes to an improvement in the quality of life. At the same time, there exist various challenges within the recommender system, mainly cold start and scalability. To effectively address the inefficiencies, we propose combined hybrid methods in regard to machine learning. The primary aim of this learning method is to integrate the most effective and efficient learning algorithms to examine how combined hybrid filtering can help to improve the cold star problem efficiently in the provision of personalized well-being in regard to health food service. These methods include: (1) switching among content-based and collaborative filtering; (2) identifying the user context with the integration of dynamic filtering; and (3) learning the profiles with the help of processing and screening of reflecting feedback loops. The experimental results were evaluated by using three absolute error measures, providing comparable results with other studies relative to machine learning domains. The effects of using the hybrid learning method are gathered with the help of the experimental results. Our experiments also show that the hybrid method improves accuracy by 14.61% of the average error predicted in the recommender systems in comparison to the collaborative methods, which mainly focus on the computation of similar entities.

A case of active incomplete biliary cirrhosis in an aged female Japanese macaque (Macaca fuscata).

We describe the first case of biliary cirrhosis in Japanese macaque. Clinical signs had not been detected. The liver was nodular. Histopathologically, portal-to-portal pattern of fibrosis might have indicated chronic cholestasis. Fibrotic septa were infiltrated with inflammatory cells. Therefore, this case could be diagnosed as active incomplete biliary cirrhosis.

An outbreak of toxoplasmosis in squirrel monkeys (Saimiri sciureus) in South Korea.

BACKGROUND: Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that can infect warm-blooded animals including humans. New World monkeys, such as squirrel monkeys, are more susceptible to T. gondii than Old World monkeys, often developing fatal disease. METHODS: In this study, seven of thirteen dead squirrel monkeys at Seoul Grand Park were tested to find the cause of sudden death. RESULTS: The main histopathological findings included interstitial pneumonia, necrotizing hepatitis, and splenitis. Periodic acid-Schiff staining of liver, spleen, and lung revealed cyst structures consistent with bradyzoites. Amplification of the B1 gene was detected in the liver or spleen of all monkeys. Additionally, a restriction fragment length polymorphism assay and phylogenetic analysis of the GRA6 amplicon revealed a consistent clustering with the type II strain of T. gondii. CONCLUSIONS: This study is the first report of T. gondii infection of squirrel monkeys in Korea, and the first report of type II T. gondii based on GRA6 analysis in Korea.

A study on the resistance switching of Ag2Se and Ta2O5 heterojunctions using structural engineering.

The resistive random access memory (RRAM) devices with heterostuctures have been investigated due to cycling stability, nonlinear switching, complementary resistive switching and self-compliance. The heterostructured devices can modulate the resistive switching (RS) behavior appropriately by bilayer structure with a variety of materials. In this study, the bipolar resistive switching characteristics of the bilayer structures composed of Ta2O5 and Ag2Se, which are transition-metal oxide (TMO) and silver chalcogenide, were investigated. The bilayer devices of Ta2O5 deposited on Ag2Se (Ta2O5/Ag2Se) and Ag2Se deposited on Ta2O5 (Ag2Se/Ta2O5) were fabricated for investigation of the RS characteristics by stacking sequence of Ta2O5 and Ag2Se. All operating voltages were applied to the Ag top electrode with the Pt bottom electrode grounded. The Ta2O5/Ag2Se device showed that a negative voltage sweep switched the device from high resistance state (HRS) to low resistance state (LRS) and a positive voltage sweep switched the device from LRS to HRS. On the contrary, for the Ag2Se/Ta2O5 device a positive voltage sweep switched the device from HRS to LRS, and a negative voltage sweep switched it from LRS to HRS. The polarity dependence of RS was attributed to the stacking sequence of Ta2O5 and Ag2Se. In addition, the combined heterostructured device of both bilayer stacks, Ta2O5/Ag2Se and Ag2Se/Ta2O5, exhibited the complementary switching characteristics. By using threshold switching devices, sneak path leakage can be reduced without additional selectors. The bilayer heterostructures of Ta2O5 and Ag2Se have various advantages such as self-compliance, reproducibility and forming-free stable RS. It confirms the possible applications of TMO and silver chalcogenide heterostructures in RRAM.

How Does Oyster Shell Immobilize Cadmium?

The exact mechanism of cadmium (Cd) immobilization by oyster shell (OS) has not been reported. The effect of OS on Cd immobilization and the exact mechanism should be known before applying remediation technology using OS to Cd contaminated soils. Therefore, the objective of this study was to elucidate the mechanism of Cd immobilization by OS. Three grams of OS (< 0.84 mm) was reacted with 30 mL of 0-3.56 mg Cd L-1 solution at 25 °C for 48 h. Cadmium adsorption increased with increasing initial concentration of Cd in solution. The X-ray diffraction patterns clearly demonstrated that precipitation of CdCO3 did not take place in suspensions of OS after reacting with up to 3.56 mol Cd L-1. Interestingly, we found formation of Ca0.67Cd0.33CO3 crystalline in suspension of OS after reacting with maximum initial Cd concentrations. Precipitation and chemisorption might contribute to Cd immobilization together. However, we feel confident that chemisorption is the major mechanism by which Cd immobilization occurs with OS. In conclusion, OS could be an effective bioadsorbent to immobilize Cd through formation of geochemically stable Cd mineral.

The occurrence of vascular displacement into intervertebral disc space following the compensated sagittal imbalance of the spine: a case report and review of literature.

BACKGROUND: It is known that sagittal compensating mechanisms are created for counteracting sagittal imbalance problems; however, they can sometimes be associated with incidents which affect the plan of management. PURPOSE: The purpose of this study was to report a case of the occurrence of common iliac vessel displacement into the intervertebral disc space following one of the spinal compensatory mechanisms. MATERIAL AND METHODS: The authors demonstrated this case by showing the patient history, physical examination, imaging studies, and treatment strategy as well as by reviewing some related literature. RESULTS: An 81-year-old woman presented with a long history of low back pain with claudication. An upright plain radiograph and flexion-extension study demonstrated a progressive local thoracolumbar kyphosis and losing of lumbar lordosis with significant widening of the intervertebral disc space of L4-L5. An MRI scan and 3D volume rendering spiral computed tomography (3D-CT) revealed an abnormal content which was depicted as common iliac vessels inside the disc space of L4-L5. Consequently, a rare case of the occurrence of common iliac vessel displacement into the intervertebral disc space following one of the spinal compensatory mechanisms was reported. CONCLUSION: The occurrence of vascular displacement into the intervertebral disc space related to lumbar hyperextension, as a compensating mechanism, is a rare incident but can occur. Consequently, when this mechanism presents with abnormal widening of the intervertebral disc space, especially at the low lumbar level, it should raise surgeon's concern about the probability of vascular injury when performing a disc procedure. Thorough investigation with imaging studies and selecting the optimum surgical treatment are warranted.

Intraoperative factors affecting conversion from cruciate retaining to cruciate substituting in total knee arthroplasty.

PURPOSE: The purpose of this study was to analyse the factors affecting the conversion from posterior cruciate ligament (PCL)-retaining (CR) to PCL-substituting (PS) prostheses during total knee arthroplasty (TKA). METHODS: A total of 920 TKAs, which had been preoperatively planned to undergo implantation of CR-type prostheses, were reviewed retrospectively. Of these, 83 knees (9.0 %) were converted intraoperatively to PS prostheses. The clinical and radiological factors of the non-converted (CR) and converted (PS) groups were compared. Clinically, age, gender, body mass index, angle of flexion contracture, size of the femoral component, and thickness of the polyethylene insert were compared between the CR and PS groups. Radiologically, the severity of the varus deformity and the posterior tibial slope angle (PSA) were compared between the CR and PS groups. RESULTS: No significant differences in age, gender, body mass index, range of motion, thickness of the polyethylene insert, or severity of varus deformity were identified. The average preoperative angle of flexion contracture was 5.9° ± 7.4° in the CR group and 8.1° ± 9.1° in the PS group (p = 0.002). The average preoperative PSA was 9.6° ± 4.0° in the CR group and 11.0° ± 5.0° in the PS group (p = 0.018). The conversion rates to a PS-type femoral component of size C, D, and E were 13.1, 7.0, and 6.3 %, respectively (p = 0.004). CONCLUSION: The conversion rate from CR- to PS-type prostheses was high in patients with severe flexion contracture, steep posterior slope, and a small femoral component size. These factors should be carefully considered for appropriate selection of prosthesis type. LEVEL OF EVIDENCE: IV.

Expression and immunogenic analysis of recombinant polypeptides derived from capsid protein VP1 for developing subunit vaccine material against hepatitis A virus.

Three recombinant polypeptides, VP1-His, VP1-3N-His, and 3D2-His, were produced by Escherichia coli expression system. Recombinant VP1-His, VP1-3N-His, and 3D2-His were expressed as bands with molecular weights of 32, 38, and 30 kDa, respectively. These were purified by affinity chromatography using Ni-NTA Fast-flow resin and/or ion-exchange chromatography using DEAE-Sepharose Fast-flow resin. Intraperitoneal immunizations of recombinant polypeptides successfully elicited the productions of VP1-His, VP1-3N-His, and 3D2-His specific IgG antibodies (IgG subclass distribution of IgG1>IgG2a>IgG2b>IgG3) in sera and induced the secretions of cytokines IFN-γ and IL-6 in spleen cells. Sera from recombinant VP1-His-, VP1-3N-His-, and 3D2-His-immunized mice neutralized the propagation of HAV. The highest neutralizing activity was shown in sera from recombinant VP1-3N-His-immunized mice. These results suggest that recombinant VP1-3N-His can be a useful source for developing hepatitis A virus (HAV) subunit vaccine candidates.

Thinning enhances forest soil C storage by shifting the soil toward an oligotrophic condition.

Forests are significant carbon reservoirs, with approximately one-third of this carbon stored in the soil. Forest thinning, a prevalent management technique, is designed to enhance timber production, preserve biodiversity, and maintain ecosystem functions. Through its influence on biotic and abiotic factors, thinning can profoundly alter soil carbon storage. Yet, the full implications of thinning on forest soil carbon reservoirs and the mechanisms underpinning these changes remain elusive. In this study, we undertook a two-year monitoring initiative, tracking changes in soil extracellular enzyme activities (EEAs), microbial communities, and other abiotic parameters across four thinning intensities within a temperate pine forest. Our results show a marked increase in soil carbon stock following thinning. However, thinning also led to decreased dissolved organic carbon (DOC) content and a reduced DOC to soil organic carbon (SOC) ratio, pointing toward a decline in soil carbon lability. Additionally, fourier transform infrared spectroscopy (FTIR) analysis revealed an augmented relative abundance of aromatic compounds after thinning. There was also a pronounced increase in absolute EEAs (per gram of dry soil) post-thinning, implying nutrient limitations for soil microbes. Concurrently, the composition of bacterial and fungal communities shifted toward oligotrophic dominance post thinning. Specific EEAs (per gram of soil organic matter) exhibit a significant reduction following thinning, indicating a deceleration in organic matter decomposition rates. In essence, our findings reveal that thinning transitions soil toward an oligotrophic state, dampening organic matter decomposition, and thus bolstering the soil carbon storage potential of forest. This study provides enhanced insights into the nuanced relationship between thinning practices and forest soil carbon dynamics, serving as a robust foundation for enlightened forest management strategies.

Net global warming potential index rather than soil carbon stock change could provide better understanding of the carbon balance in soil systems.

This study was conducted to determine the soil organic carbon (SOC) stock change factor for green manure crops that was developed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method and compare this with the net global warming potential (GWP) index that is used to evaluate the contribution of green manuring to global warming. Four treatments were barley (Hordeum vulgare L.; B), hairy vetch (Vicia villosa R.; HV), a barley/hairy vetch mixture (BHV) and a conventional treatment (C). The aboveground biomass of green manure crops was incorporated into the soil on 25 May 2018, 26 April 2019, 29 April 2020, 30 April 2021 and 2 May 2022. Maize (Zea mays L.) was transplanted as the subsequent crop after the incorporation of green manures. SOC stock decreased with green manures, even though carbon input with green manures, including B, HV and BHV, was greater than that with C. The mean value of the SOC stock change factor for green manure crops, including B, HV and BHV was 0.627 and was significantly lower than that of the C. However, the net GWP also decreased with the incorporation of green manure crops, and the mean value of the relative net GWP index across B, HV and BHV was 0.853. These conflicting results were caused by different estimation methods between annual SOC change (△SOC) and net GWP. The estimation of SOC stock change using △SOC suggested by the IPCC method may overestimate the contribution of green manure crops to global warming. The net GWP method with comprehensive input and output of carbon in the soil system could provide a better understanding of the carbon balance in soil systems. In the current study, the comparison of △SOC and net GWP was conducted for at one site of upland soil for 5 years. Therefore, further research on estimating the effect of green manure crops on net GWP in various types of soil for longer years should be conducted.

Peptide-Decorated Microneedles for the Detection of Microplastics.

The escalating utilization of plastics in daily life has resulted in pervasive environmental pollution and consequent health hazards. The challenge of detecting and capturing microplastics, which are imperceptible to the naked eye, is exacerbated by their diminutive size, hydrophobic surface properties, and capacity to absorb organic compounds. This study focuses on the application of peptides, constituted of specific amino acid sequences, and microneedles for the rapid and selective identification of microplastics. Peptides, due to their smaller size and greater environmental stability compared with antibodies, emerge as a potent solution to overcome the limitations inherent in existing detection methodologies. To immobilize peptides onto microneedles, this study employed microneedles embedded with gold nanorods, augmenting them with sulfhydryl (SH) groups at the peptides' termini. The sensor developed through this methodology exhibited efficient peptide binding to the microneedle tips, thereby facilitating the capture of microplastics. Raman spectroscopy was employed for the detection of microplastics, with the results demonstrating successful attachment to the microneedles. This novel approach not only facilitates localized analysis but also presents a viable strategy for the detection of microplastics across diverse environmental settings.

A Novel Passive Shoulder Exoskeleton Using Link Chains and Magnetic Spring Joints.

Work-related musculoskeletal disorders represent a major occupational disability issue, and 53.4% of these disorders occur in the back or shoulders. Various types of passive shoulder exoskeletons have been introduced to support the weight of the upper arm and work tools during overhead work, thereby preventing injuries and improving the work environment. The general passive shoulder exoskeleton is constructed with rigid links and joints to implement shoulder rotation, but there exists a challenge to align with the flexible joint movements of the human shoulder. Also, a force-generating part using mechanical springs require additional mechanical components to generate torque similar to the shoulder joint, resulting in increased overall volume and inertia to the upper arm. In this study, we propose a new type of passive shoulder exoskeleton that uses magnetic spring joint and link chain. The redundant degrees of freedom in the link chains enables to follow the shoulder joint movement in the horizontal direction, and the magnetic spring joint generates torque without additional parts in a compact form. Conventional exoskeletons experience a loss in the assisting torque when the center of shoulder rotation changed during arm elevation. Our exoskeleton minimizes the torque loss by customizing the installation height and initial angle of the magnetic spring joint. The performances of the proposed exoskeleton were verified by an electromyographic evaluation of shoulder-related muscles in overhead work and box lifting task.

Characteristics of Synaptic Function of Mesoporous Silica-Titania and Mesoporous Titania Lateral Electrode Devices.

In this paper, we have fabricated non-volatile memory resistive switching (RS) devices and analyzed analog memristive characteristics using lateral electrodes with mesoporous silica-titania (meso-ST) and mesoporous titania (meso-T) layers. For the planar-type device having two parallel electrodes, current-voltage (I-V) curves and pulse-driven current changes could reveal successful long-term potentiation (LTP) along with long-term depression (LTD), respectively, by the RS active mesoporous two layers for 20~100 µm length. Through mechanism characterization using chemical analysis, non-filamental memristive behavior unlike the conventional metal electroforming was identified. Additionally, high performance of the synaptic operations could be also accomplished such that a high current of 10-6 Amp level could occur despite a wide electrode spacing and short pulse spike biases under ambient condition with moderate humidity (RH 30~50%). Moreover, it was confirmed that rectifying characteristics were observed during the I-V measurement, which was a representative feature of dual functionality of selection diode and the analog RS device for both meso-ST and meso-T devices. The memristive and synaptic functions along with the rectification property could facilitate a chance of potential implementation of the meso-ST and meso-T devices to neuromorphic electronics platform.

Low Dielectric Constant Characteristics of Styrene and Maleimide Anhydride Copolymer with Modification for High Frequency Application of Printed Circuit Board.

Recently, due to the intensive and fast progress of the high frequency wireless communication environment, including 5th generation (5G) wireless communication, more robust substrate for printed circuit board (PCB) application, especially with less power consumption, is required. In this study, modified resins based on styrene-maleic anhydride (SMA) copolymer were prepared and evaluated as binder resin to accomplish a low dielectric constant or relative permittivity (εr: <3.0) substrate for the PCB application under ultrahigh frequencies (UHF; 1 GHz~9.4 GHz). The low εr dielectric characteristics of the modified SMA copolymer could be correlated with effects from the stereo-structure of carbon chains or conformational orientation, where the degree of crystallization was analyzed by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopies. Prepreg films of the low εr modified SMA copolymers and their compounds with epoxy resins were also characterized in terms of dielectric loss or dissipation factor (Df), which have shown more noticeable relation with their stereo-structures as well.