Mechanism and Control of Continuous-State Coupled Elastic Actuation

Focusing on the physical interaction between people and machines within safety constraints in versatile situations, this paper proposes a new, efficient, coupled elastic actuation (CEA) to provide future human-machine systems with an intrinsically programmable stiffness capacity to shape the output force corresponding to the deviation between human motions and the set positions of the system. As a possible CEA system, a prototype of a two degrees of freedom (2-DOF) continuous-state coupled elastic actuator (CCEA) is designed to provide a compromise between performance and safety. Using a pair of antagonistic four-bar linkages, the inherent stiffness of the system can be adjusted dynamically. In addition, the optimal control in a simple various stiffness model is used to illustrate how to find the optimal stiffness and force trajectories. Using the optimal control results, the shortest distance control is proposed to control the stiffness and force trajectory of the CCEA. Compared to state-of-the-art variable stiffness actuators, the CCEA system is unique in that it can achieve near-zero mechanical stiffness efficiently and the shortest distance control provides an easy way to control various stiffness mechanisms. Finally, a CCEA exoskeleton is built for elbow rehabilitation. Simulations and experiments are conducted to show the desired properties of the proposed CCEA system and the performance of the shortest distance control.National Science Council (China) (grants NSC 100-2221-E-002-127-MY3 and NSC 100-2221-E-002-077- MY3

Potency of exosomes from Adult-derived human liver stem cells (ADHLSCs) to treat Crigler Najjar syndrome

Background and aims Extracellular vesicles, EVs (MP, microparticles; and EXO, exosomes) are nano-size vesicles released by many cell types. They mediate intracellular communication by delivering proteins, lipids and/or genetic information (coding and non-coding RNAs) to recipient cells. Adult-derived human liver stem cells (ADHLSCs) are currently in clinical development for the treatment of liver diseases. Clinical and preclinical data seem to indicate a higher clinical effect than what could be expected from the number of cells that have engrafted, suggesting that other mechanisms may be at play. Therefore, we aim to know whether the EVs have therapeutic effects and whether they can contribute to ADHLSC-mediated correction of Crigler Najjar syndrome. Methods ADHLSCs were cultured for 2 days in DMEM supplemented with 10% EXO free FBS and 1% P/S. The conditioned medium was collected, and MP and EXO fractions were harvested by serial centrifugation. FACS and western blotting were used to evaluate the presence of MP and EXO using specific markers. RT-qPCR was performed on RNA extracted from the MP and EXO to investigate the presence of mRNAs of interest in each sample. Results We demonstrated that CD40L, a specific marker of MP, is expressed in ADHLSC-derived MP, while ALIX and CD9, which are specific EXO markers, are expressed in ADHLSC-derived EXO. ALIX was also highly expressed in the EXO fraction derived from a metabolic donor suffering from Crigler-Najjar syndrome, showing that this “EXO marker” can be found in EXO from both healthy and metabolic sources. In order to analyze the EXO fraction by flow cytometry, EXO were incubated with EXO-specific beads and stained for CD9. Using this method, we were able to confirm the expression of CD9 at the surface of the EXO. Characterization of the mRNA by qPCR showed a high expression of UGT1A1 in EXO. This finding supports the hypothesis that EXO may play a role in ADHLSC-mediated correction of Crigler-Najjar syndrome. Conclusions In summary, our study shows that we are able to isolate and characterize MP and EXO released by ADHLSCs. High expression of UGT1A1 mRNA in EXO may support a potential role for ADHLSC-derived EXO in the treatment of Crigler-Najjar syndrome. Further work will be needed to confirm this hypothesis. Keywords ADHLSCs, Extracellular vesicles, Exosomes, Crigler-Najjar, UGT1A

Contribution of extracellular vesicles from Adult-derived human liver stem cells to the correction of Urea Cycle Disorders

Introduction Adult-derived human liver stem cells (ADHLSCs) are currently in clinical development for the treatment of Urea Cycle Disorders (UCD). Clinical and preclinical data seem to indicate a higher clinical effect than what could be expected from the number of cells that have engrafted, suggesting that other mechanisms may be at play. We have previously demonstrated that ADHLSCs produce Extracellular Vesicles, EVs (MP, microparticles; and EXO, exosomes), which have been shown to mediate intracellular communication in other systems by delivering proteins, lipids and/or genetic information (coding and non-coding RNAs) to recipient cells. Therefore, the aim of this study was to determine the precise role of EVs in ADHLSC-mediated correction of UCD. Methods ADHLSCs were cultured for 2 days in DMEM supplemented with 10% EXO-free FBS and 1% P/S. The conditioned medium was collected, and MP and EXO fractions were harvested by serial ultracentrifugation. Transmission electron microscopy (TEM), western blotting and nanoparticle tracking analysis were used to evaluate the presence, purity and abundance of MP and EXO. RNA from EVs was stained with SytoRNA, which only fluoresces upon integration into RNA, to investigate RNA transfer from EVs to rat hepatocytes. Droplet digital PCR (ddPCR) was performed on RNA extracted from the MP and EXO as well as rat hepatocytes previously incubated with EVs to investigate the presence of human mRNAs of interest. Results We confirmed that ADHLSCs produce both MP and EXO. Characterization of the mRNA by ddPCR showed expression of ASL, ASS, and CPS1 in EVs, mainly in MPs. SytoRNA staining of the EV RNA allowed us to show transfer of EV RNA to over 60% of rat hepatocytes in vitro. Finally, we demonstrated transfer of human mRNAs of interest from EVs to rat hepatocytes using ddPCR. Summary/Conclusion In summary, our study shows that ADHLSC-derived EVS contain mRNA encoding for some of the deficient enzymes in UCD and are capable of transfering their mRNA content to recipient cells. mRNA transfer via EVs may therefore be one of the modes of action of ADHLSCs in UCD

CHA2DS2VASc score predicts risk of end stage renal disease in patients with atrial fibrillation: Long-term follow-up study

Background: End stage renal disease (ESRD) is an increasing worldwide epidemic disease. CHA2DS2-VASc score is a well-established predictor of cardiovascular outcome among atrial fibrillation (AF) patients. Objective: The aim of this study was to test whether CHA2DS2-VASc score is a good predictor for incident ESRD events. Methods: This is a retrospective cohort study (from January 2010 to December 2020) with median follow-up of 61.7 months. Clinical parameters and baseline characteristics were recorded. The endpoint was defined as ESRD with dialysis dependent. Results: The study cohort comprised 29,341 participants. Their median age was 71.0 years, 43.2% were male, 21.5% had diabetes mellitus, 46.1% had hypertension, and mean CHA2DS2-VASc score was 2.89. CHA2DS2-VASc score was incrementally associated with the risk of ESRD status during follow-up. Using the univariate Cox model, we found a 26% increase in ESRD risk with an increase of one point in the CHA2DS2-VASc score (HR 1.26 [1.23–1.29], P < 0.001). And using the multi-variate Cox model adjusted by initial CKD stage, we still observed a 5.9% increase in risk of ESRD with a one-point increase in the CHA2DS2-VASc score (HR 1.059 [1.037–1.082], P < 0.001). The CHA2DS2-VASC score and the initial stage of CKD were associated with the risk of ESRD development in patients with AF. Conclusions: Our results first confirmed the utility of CHA2DS2-VASC score in predicting progression to ESRD in AF patients. The efficiency is best in CKD stage 1

Manipulating ATP supply improves in situ CO2 recycling by reductive TCA cycle in engineered Escherichia coli

The reductive tricarboxylic acid (rTCA) cycle was reconstructed in Escherichia coli by introducing pGETS118KAFS, where kor (encodes α-ketoglutarate:ferredoxin oxidoreductase), acl (encodes ATP-dependent citrate lyase), frd (encodes fumarate reductase), and sdh (encodes succinate dehydrogenase) were tandemly conjugated by the ordered gene assembly in Bacillus subtilis (OGAB). E. coli MZLF (E. coli BL21(DE3) Δzwf, Δldh, Δfrd) was employed so that the C-2/C-1 [(ethanol + acetate)/(formate + CO2)] ratio can be used to investigate the effectiveness of the recombinant rTCA for in situ CO2 recycling. It has been shown that supplying ATP through the energy pump (the EP), where formate donates electron to nitrate to form ATP, elevates the C-2/C-1 ratio from 1.03 ± 0.00 to 1.49 ± 0.02. Similarly, when ATP production is increased by the introduction of the heterologous ethanol production pathway (pLOI295), the C-2/C-1 ratio further increased to 1.79 ± 0.02. In summary, the ATP supply is a rate-limiting step for in situ CO2 recycling by the recombinant rTCA cycle. The decrease in C-1 is significant, but the destination of those recycled C-1 is yet to be determined

An Artificial Intelligence-Enabled ECG Algorithm for the Prediction and Localization of Angiography-Proven Coronary Artery Disease

(1) Background: The role of using artificial intelligence (AI) with electrocardiograms (ECGs) for the diagnosis of significant coronary artery disease (CAD) is unknown. We first tested the hypothesis that using AI to read ECG could identify significant CAD and determine which vessel was obstructed. (2) Methods: We collected ECG data from a multi-center retrospective cohort with patients of significant CAD documented by invasive coronary angiography and control patients in Taiwan from 1 January 2018 to 31 December 2020. (3) Results: We trained convolutional neural networks (CNN) models to identify patients with significant CAD (&gt;70% stenosis), using the 12,954 ECG from 2303 patients with CAD and 2090 ECG from 1053 patients without CAD. The Marco-average area under the ROC curve (AUC) for detecting CAD was 0.869 for image input CNN model. For detecting individual coronary artery obstruction, the AUC was 0.885 for left anterior descending artery, 0.776 for right coronary artery, and 0.816 for left circumflex artery obstruction, and 1.0 for no coronary artery obstruction. Marco-average AUC increased up to 0.973 if ECG had features of myocardial ischemia. (4) Conclusions: We for the first time show that using the AI-enhanced CNN model to read standard 12-lead ECG permits ECG to serve as a powerful screening tool to identify significant CAD and localize the coronary obstruction. It could be easily implemented in health check-ups with asymptomatic patients and identifying high-risk patients for future coronary events

A genomic-augmented multivariate prognostic model for the survival of Natural-killer/T-cell lymphoma patients from an international cohort.

10.1002/ajh.26636Am J Hemato