Solanum okadae clone were characterized. Each mitogenome was assembled and annotated from Pacific Biosciences (PacBio) long reads and 10X genomics short reads. The results show that each mitogenome consists of multiple circular molecules with similar structure and gene organization, though two groups  could be distinguished, and two mitogenomes (clone 10908-06 and OKA15) were not consistent with those or with each other. Significant differences in the repeat structure of the 10 mitogenomes were found, as was recombination events leading to multiple sub-genomic circles. Comparison between individual molecules revealed a translocation of ∼774 bp region located between a short repeat of 40 bp in molecule 3 of each mitogenome, and an insertion of the same in molecule 2 of the 10908-06 mitogenome. Finally, phylogenetic analyses revealed a close relationship between the mitogenomes of these clones and previously published potato mitogenomes.The potato mitogenome is complex and to understand various biological functions and nuclear–cytoplasmic interactions, it is important to characterize its gene content and structure. In this study, the complete mitogenome sequences of nine diploid potato clones along with a diploid  Given the diversity within the potato mitogenome, it is necessary to utilize the latest technologies to better understand its landscape of genetic variation, evolution and structural rearrangements.The potato mitochondrial genome is also complicated and often reported as a multichromosomal type architecture with both circular and linear DNA molecules.S. tuberosum) and one clone of Solanumokadae. The results show that these mitogenomes exist as multiple individual molecules with intra-molecular recombination events leading to multiple isoforms and sub-genomic circles. We have also identified key differences in these mitogenomes through comparative analyses. Finally, we have investigated the relationships between these clones and publicly available potato mitogenomes of diverse taxa through phylogenetic analyses.In the present study, we have used long-read and short-read data to successfully assemble and analyse recombination in nine diploid potato clones  and a wild relative https://www.10xgenomics.com/) and PacBio SMRT  sequencing technology.Total genomic DNA was extracted from the leaves of each clone using the DNeasy Plant Mini Kit (Qiagen) following the manufacturer’s instructions for plant tissue. Sequencing of the ten clones was carried out using both 10X Genomics’ GemCode technology  for each clone. In addition, the same 33 genes from 13 published mitogenomes of a panel of diverse taxa,,S. tuberosum cultivars (Cicero and Désirée)http://tree.bio.ed.ac.uk/software/figtree/). Furthermore, a plastome phylogeny was constructed for the same genomes except Cicero and Désirée (their plastome assemblies are not available) to determine congruency between both phylogenetic trees.,Insilco PCR experiments.A phylogenetic tree was constructed from the coding sequences of the 33-common protein-coding genes (S. tuberosum) for which the plastomes were recently assembledS. okadae. The results reveal a multichromosomal nature of their mitochondrial DNA, as each mitogenome was assembled into multiple individual molecules. The clones 07506-01, DW84-1457, 08675-21 and H412-1 were assembled into four circular molecules , nine NADH dehydrogenases , 11 ribosomal proteins , four cytochrome C biogenesis group genes , three cytochrome c oxidases , two succinate dehydrogenases , one cytcochrome c reductase (cob), one maturase (matR), and a transport membrane protein (mttB). All 10 mitogenomes have a functional cob gene while a truncated cob gene copy is also present in all but the OKA15 mitogenome. Three types of rRNAs , and 22 tRNAs (corresponding to 16 amino acids) are present in each mitogenome  is very different compared with the rest of the mitogenomes (from S. tuberosum clones)  is not observed in any of these mitogenomes.cox2, rpl16, rps19, rps3 and orf102, though in OKA15 the R2 repeat is reduced, resulting in a truncated copy of the second cox2 gene.Repeats are an integral part of plant mitogenomes and they range from several hundred bp to several thousand bp. clones) . We have,Recombination in plant mitochondria is very frequent because of the high repeat content, resulting in multiple isoforms, loss of synteny and genomic rearrangements.rpl10 and rpl2 genes in group B and OKA15 . An interesting region of observation is the arrangement of the nd rps10 . In 1090A short repeat sequence of 40 bp was found on both sides of the translocated region in each molecule 3 . Interes,The green arrows in S. tuberosum cultivars.S. tuberosum cultivars Cicero and Désirée closer to group A clones corelates with the sequence similarity found between them. Similarly, group B mitogenomes are also clustered together in one clade along with S. phureja (PHU), S. stenotomum subsp. stenotomum (STN), S. stenotomum subsp. goniocalyx (GON1), S. stenotomum subsp. goniocalyx (GON2), Solanumcurtilobum (CUR), and Solanumbukasovii (BUK1). There is a close relationship between 10908-06 and S. tuberosum subsp. tuberosum (TBR), as well as between OKA15 and S. bukasovii (BUK2). A plastome phylogenetic tree was built for the same species to observe the similarities/differences that could account for potential paternal mitochondrial DNA leakage. However, all the mitogenomes have similar groupings in both phylogenetic trees, except for Solanumjuzepczukii (JUZ), which is grouped with Solanumajanhuiri (AJH) in the plastome phylogeny but is closer to group A genomes in the mitogenome phylogeny . There were three clones where the paternal clone was also included in the study—12625-02, 08675-21 and 10908-06 (Supplementary Table S1). While 10908-06 clustered away from its paternal parent clone (H412-1), 12625-02 and 08675-21 did cluster together with their paternal parent clones, 11379-03 and 07506-01, respectively. Cytoplasms are inherited maternally, and similarity of paternal mitogenomes with progeny clones suggests potential leakage of paternal mitogenomes.A phylogenetic tree was constructed for these 10 mitogenomes with an additional 13 previously published mitogenomes of diverse potato taxa,,S. okadae is completely different from the rest of the mitogenomes in this study and those in previously reported studies.In this study, the mitogenomes of 10 diploid potato clones were assembled, annotated, and compared to explore their genetic diversity. Multichromosomal type arrangement in these mitogenomes were observed, consistent with the results from previous studies on potato mitogenomes.dsab009_Supplementary_DataClick here for additional data file.


Journal of Materials Science: Materials in Medicine (2020) 31:80Correction to: 10.1007/s10856-020-06418-1.In Section 2.2 Surgery; the 3rd sentence contains a minor typographical error. The sentence should read as follows: ‘Following gaseous anaesthesia, 11 × 20 mm defects were created into the cancellous bone of the distal femur and proximal tibia.’


The development of atherosclerosis was considered as the common cause of the stenosis of coronary artery grafts. Left internal mammary artery (LIMA) was the best artery graft for further effectiveness of coronary artery bypass grafting (CABG). We sought to assess the impact of known conventional cardiovascular risk factors (RFs) on LIMA graft stenosis.A retrospective study including 618 participants, who had recurrence of chest pain after CABG, aged ≥18 years, hospitalized for coronary angiography in Beijing Anzhen hospital between 2010 and 2017 was performed. All the participants were confirmed to have LIMA graft. Multivariate analysis was conducted to determine the relationship between conventional RFs and LIMA graft stenosis.Of the study, 220 (35.6%) participants continued to smoke, 504 (81.6%) were overweight or obese, and 411 (66.5%) and 242 (39.2%) reported concomitant hypertension and diabetes, respectively. LIMA graft stenosis occurred in 161 participants (26.1%). Postoperative smoking, a CABG duration of ≥10 years and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis, the odds ratio (OR) was 1.86 [95% confidence interval (CI): 1.26–2.78], 2.24 (95%CI:1.33–3.478), and 2.44(95% CI:1.39–4.32), respectively. Statin use  and low-density lipoprotein cholesterol (LDL-C) < 1.8 mmol/L  had a significantly decreased risk of LIMA graft stenosis. While, only 15.4% (95/618) achieved the target LDL-C level.Postoperative smoking and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis. Statin use and LDL-C <1.8 mmol/L decreased the risk. Coronary artery bypass graft (CABG) surgery is the most complete and durable treatment of left main coronary artery and three-vessel coronary severe stenosis or occlusion disease and has been an established therapy for nearly 50 years. Following CABG, effects should be done to reduce the recurrence of cardiovascular event. Studies have shown that the recurrence rate of angina is 17% in 1 year after CABG and 63% in 10 years after CABG .The grafts were saphenous vein (SV), left internal mammary artery (LIMA), right internal mammary artery (RIMA) and radial artery (RA). Using graft from LIMA to the left anterior descending artery (LAD) improves the effectiveness of CABG with high long-term patency rate . The greThe patency rate of grafts rapidly increases within the first year after CABG and then slowly,which was attributed to anastomotic site stenosis between 1 month and 1 year and atherosclerosis development of the bypass graft 1 year later . DyslipiThis study was based on a retrospective, single-center analysis of patients who had recurrence of chest pain after CABG and had subsequent coronary angiographic findings in the Department of Cardiology of Beijing Anzhen Hospital from January 2010 to December 2017. All the participants were enrolled through the hospital's electronic record system. The inclusion criteria were an age of ≥18 years; recurrence of chest pain after CABG; completed electronic medical records and coronary angiographic findings; underwent LIMA-LAD graft. The exclusion criteria were CABG within 1 year before the start of the study; second CABG; renal insufficiency requiring dialysis treatment; and/or cancer.Data regarding the patients' demographics, conventional RFs for CVD, coronary angiographic findings and medication intake were collected from the hospital records by trained abstractors, using physician notes, laboratory reports, patient histories, and discharge summaries. A structured questionnaire was developed. Demographic information consisted of gender, age; conventional RFs included Overweight/obese, medical history of hypertension and diabetes, LDL-C level and smoking details. Basic medication therapy for secondary prevention to cardiovascular events included the usage of aspirin, β-blocker, angiotensin receptor blockers (ARB)/angiotensin-converting enzyme inhibitors (ACEI) and statins (dosage and type of those drugs were not obtained in the study). Height, weight, and blood pressure were measured in ward and recorded. The fasting plasma glucose (FPG) and LDL-C concentrations were examined while the patients were hospitalized. Coronary angiographic findings was reviewed, occlusion or stenosis of the native coronary arteries  and artery grafts were recorded. Number and stenosis of SV graft was not collected in this study.2, an overweight status was defined as a BMI of 24.0 to 27.9 kg/m2, and obese was defined as a BMI of ≥ 28.0 kg/m2. Ideal target of LDL-C was defined as an LDL-C concentration of <1.8 mmol/L (70 mg/dl). Ideal target of blood glucose was defined as an FPG of <7 mmol/L (126 mg/dl). The presence of hypertension or diabetes was defined by a previous diagnosis of hypertension or diabetes in the document of diagnosis on admission or summary of history. Nonsmokers were defined as patients who had never smoked, ever-smokers who stopped smoking at least 6 months, and current smokers were defined as those who were smoking every day or some days after CABG or stopped smoking <6 months at the time of interview.Chest pain was identified based on induction factor, position pain, feature of pain, pain duration, radiating pain and remission. We defined severe stenosis for native coronary artery as stenosis of ≥50% for left main, ≥70% for left anterior descending, circumflex, and right coronary arteries; defined artery graft disease as stenosis of ≥50%, and at least 1 stenosis was measure in LIMA based on angiography. Uncontrolled blood pressure was defined as SBP of ≥140 mmHg and / or DBP of ≥90 mmHg, and controlled blood pressure was defined as SBP of <140 mmHg and DBP of <90 mmHg. The body mass index (BMI) was calculated as body mass in kilograms divided by height in meters squared. Normal weight was defined as a BMI of <24.0 kg/mt-test was used to compare two independent samples. Categorical variables are expressed as proportions. The chi-square test was used to compare the differences in proportions between different groups. Multiple backward stepwise logistic regressions were performed to identify the association between risk factors and artery graft disease. All significant variables based on the chi-square test were entered into a multivariate model. All reported P values were two-tailed, and P < 0.05 were considered statistically significant.The statistical analysis was performed with SPSS software for Windows, version 18.0 . Normally distributed continuous variables are presented as means ± standard deviations. A student's n = 500, female: n = 118), 13 (2.1%) together with RIMA graft and 4 (0.65%) together with RA graft. The age ranged from 37 to 75 years . Mean interval after CABG was 6.4 ± 3.5 years (range from 1 to 18 years), and 83.8% of them had undergone CABG <10 years prior to the study. The prevalence of conventional RFs was postoperative smoking 220 (35.6%), overweight or obese 504 (81.6%), hypertension 411 (66.5%), diabetes 242 (39.2%), and 15.4% (95 of 618) achieved LDL-C target level of <1.8 mmol/L. Recurrent angina was the most common presentation . According to the cut-off point of coronary artery stenosis, 298 (48.2%) patients had a left main disease, 473 (76.5%), 383 (62.0%), and 269 (43.5%) had a severe stenosis in LAD, circumflex coronary artery, and right coronary artery, respectively. LIMA graft stenosis occurred in 161 participants (26.1%). Main characteristics of the overall sample are presented in A total of 618 participants . For mean level of SBP, DBP, FPG and BMI, no correlation with LIMA graft stenosis were observed . Higher proportion of patients with LDL-C <1.8 mmol/L was observed in patients without LIMA graft stenosis than that in those with LIMA graft stenosis . There were significant differences in the proportion of FPG <7.0 mmol/L and smoking cessation across LIMA graft stenosis groups (P <0.05). There were no significant differences of in the proportion of BMI <24 kg/m2 and BP <140/90 mmHg between the two groups . It was more frequent among patients without history of diabetes who had an FPG≥7.0 mmol/L, with postoperative smoking, or with a duration of CABG≥10 years ; lower prevalence was observed among patients with LDL-C <1.8 mmol/L and taking statin (P = 0.001). Multivariate logistic regression analysis was performed to identify the association between conventional RFs and LIMA graft disease. LIMA graft disease correlated with high blood glucose without diabetes , postoperative smoking  and duration of CABG≥10 years , LDL-C achieved target level  and statin use . Details are given in Of 618 patients, 161 (26.1%) developed LIMA graft stenosis, which did not vary by sex, age group, BP group, BMI group, and use of aspirin, ACEI/ARB and β-blocker . In total, 95 patients (15.4%) achieved target LDL-C level, and the figure was 17.4% (72/413) in treated patients. Regardless of the treated patients or the overall sample, the frequency of achieving target LDL-C level of patients with LIMA graft stenosis was lower than that of patients without LIMA graft stenosis  were taking statins, there was no significant difference in statin use among different duration of CABG, but it appeared to be lower in women, patients aged ≥65 years, and patients with LIMA graft stenosis  of 22.3% for CVD . But it Diabetes is an important predictor of CVD , its infLDL-C lowering reduced the risk of recurrent ischemic cardiovascular events, guidelines on the management of blood cholesterol recommended a target LDL-C concentration of <1.8 mmol/L for patients with CVD to reduce recurrent risk  even <1.Although some cross-sectional studies did not show the association between postoperative smoking and coronary artery graft lesions , follow-The major limitation of this study is a single center and retrospective analysis, all the information was absorbed from the hospital electronic medical records, detail information about diet, physical inactivity and dosage of medication was not collected, therefore it is likely that there is a selection and recall bias related to the inquiry of medical history and the structured questionnaire. The sample size of the present study was also limited. In addition, we aimed to evaluate the effect of traditional RFs for CVD on artery graft stenosis, other RFs  that migThis study provides more evidence for the RFs of coronary artery grafts artery, not all conventional risk factors were positively associated with artery graft stenosis. Long duration after CABG and postoperative smoking were identified as a potential risk factor, hyperglycemia without diabetes, it should be noted, had a high prevalence of artery graft stenosis. Statin use and LDL-C <1.8 mmol/L might be protective. The results will help clinicians to take both lifestyle and pharmacological interventions to reduce artery graft lesions risk.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding authors.The studies involving human participants were reviewed and approved by the Institutional Review Boards of Beijing Anzhen Hospital, Capital Medical University, Beijing, China. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.H-JZ and X-TS conceived and designed the study. H-JZ and H-XY prepared the database, performed the analysis, interpreted results, and drafted the manuscript. NN and J-WW prepared the database. X-TS interpreted results and performed critical revision of the manuscript. All authors read and approved the final version of the manuscript.This research received a research grant from Beijing Municipal Science and Technology (No. Z16110000016139).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The presented works were reported in part at the BGRS (Bioinformatics of Genome Regulation and Structure/Systems Biology) traditional biannual computational biology meeting in Novosibirsk, highlighting recent advances in genomics, bioinformatics, systems biology, and biotechnology areas. This collection continues the studies in the field of bioinformatics that were presented initially in the Frontiers in Genetics journal [PeerJ journal  [International Journal of Molecular Sciences [https://www.mdpi.com/journal/ijms/special_issues/Medical_Genetics_Bioinformatics, assessed on 8 November 2021). This Special Issue is related to the topics on computational genomics in model organisms for biotechnology, discussing genomics and bioinformatics approaches for life sciences. This Special Issue, “Life: Computational Genomics”, presents research articles on systems biology applications, computational genomics, and bioinformatics methods in life sciences. The molecular mechanisms of human disease progression, as well as gene expression in laboratory animal models are studied now based on sequencing technologies and genotyping tools. This Special Issue continues the collection of papers that were published in MDPI IJMS journal “Bioinformatics of Gene Regulations and Structure”  , and recThe series of post-conference Special Issues started with a coverage of Bioinformatics of Genome Regulation and Structure (BGRS) ,6,7 confWe open this collection of papers by Bo Song et al.  presentiThe next group of papers presents applications in animal genomics. Alexander Igoshin et al.  considerFTO (fat mass and obesity-associated) gene. Associations of the FTO gene polymorphic variants were in shown [FTO gene is related to high obesity risk for in human populations [BioMed Central [Evgeniya Poltavskaya et al.  presentein shown . Note thulations . These m Central ,7. The analysis of genetics backgrounds and pathways in complex diseases such as schizophrenia, metabolic syndrome, and autism spectrum disorders demands the development of genomics and system biology methods ,26. The https://www.ancestry.com/dna/, assessed on 8 November 2021). The distinct genetic variants were found to be associated with pathways that govern host immunity, such as interferon, interleukin, and cytokine signalling, as well as known COVID-19 comorbidities, such as obesity and cholesterol metabolism [Priyanka Upadhyai et al.  discussetabolism .IJMS special issue on bioinformatics of gene regulation [https://bgrssb.icgbio.ru/2022/, assessed on 8 November 2021), and consider the next special journal issues on the genomics technologies applications at MDPI IJMS “Plant Biology and Biotechnology: Focus on Genomics and Bioinformatics” , as well as “Molecular Mechanisms of Transcriptional Regulation in Tumor Cell” at Genes journals .Overall, we are proud of the continuing Life Special Issue that we have collated together as well as gulation . We hope


We present the design, implementation, and experimental evaluation of a low-cost, customizable, easy-to-use transradial hand prosthesis capable of adapting its compliance. Variable stiffness actuation (VSA) of the prosthesis is based on antagonistically arranged tendons coupled to nonlinear springs driven through a Bowden cable based power transmission. Bowden cable based antagonistic VSA can, not only regulate the stiffness and the position of the prosthetic hand but also enables a light-weight and low-cost design, by the opportunistic placement of motors, batteries, and controllers on any convenient location on the human body, while nonlinear springs are conveniently integrated inside the forearm. The transradial hand prosthesis also features tendon driven underactuated compliant fingers that allow natural adaption of the hand shape to wrap around a wide variety of object geometries, while the modulation of the stiffness of their drive tendons enables the prosthesis to perform various tasks with high dexterity. The compliant fingers of the prosthesis add inherent robustness and flexibility, even under impacts. The control of the variable stiffness transradial hand prosthesis is achieved by an sEMG based natural human-machine interface. Versatile grasping and manipulation in unstructured environments are challenging tasks, actively investigated in robotics. Multi-fingered robot hands have been developed both in academia  , the impedance change is physical and is valid for the whole frequency spectrum, including frequencies well above the controllable bandwidth of the actuators. Furthermore, this approach consumes energy only when the impedance is being modulated; hence, is energy efficient.Achieving human level dexterity with fully actuated, high degrees of freedom prosthetic hands requires the use of complex control algorithms  and with various properties  without damaging them. In this study, we ensure dexterity by designing an underactuated hand that can mimic the opening/closing sequence of human fingers to adapt to a wide variety of geometries and by enabling the stiffness of the prosthesis to be actively modulated based on the task.The primary requirement for a hand prosthesis is ease-of-use. The control of the device should be intuitive, allowing amputees to use the device without being exposed to long training periods. Moreover, the hand prosthesis should be energy efficient and its batteries should be easily swappable for user friendliness. In this study, the use of an underactuated design simplifies the control of the device, as only the position and impedance of the drive tendon need to be controlled. The tele-impedance controller reviewed in Section II-B provides a natural sEMG interface for the control of the device, where the impedance modulation takes place automatically, allowing the amputee only to focus on the position control of the hand. Energy efficiency is ensured by hardware based impedance modulation, where no energy is wasted to maintain a desired impedance level. Finally, Bowden cable based actuation enables batteries to be opportunistically placed anywhere on the body, making them easily re-sizeable or swappable.The secondary requirements for the device are high robustness and low cost. In this study, the compliant fingers and the VSA provide built-in physical compliance that provides inherent robustness to impacts. Besides, all parts of the prosthesis are simple to manufacture and customizable. Furthermore, since Bowden cable based actuation allows for motors, drivers, and batteries of the system to be remotely located, the cost of these parts can be kept low, as strict size and weight constraints do not apply to these parts.The tele-impedance control architecture consists of two modules, as depicted in Given that transradial upper extremity amputees lack the muscle groups responsible for hand and forearm motions, sEMG signals for the position control of the hand prosthesis are measured from chest and shoulder muscles, while sEMG signals used for stiffness regulation are measured from the muscle pairs on the upper arm. The estimation of the hand position and stiffness from sEMG signals involves modeling of hand motion/stiffness based on sEMG signals, empirical determination of the parameters of these models for use in real time control, and incorporation of fatigue compensation.Conditioned sEMG signals are discretized into several levels to map them to the physical stiffness range of the VSA and the range of motion of the fingers. A calibration procedure is performed for sEMG signals before each use, to customize the maximum voluntary contraction (MVC) levels for the user, as commonly done for commercial prosthetic hands. Since the MVC levels of the sEMG signals vary in time and are specific to users, the sEMG signals have to be normalized before each use to present accurate reference data to the controller shown in the second module in The sEMG based tele-impedance control interface, together with the VSA, enables an amputee to modulate the stiffness of the prosthetic hand to properly match the requirements of the task while performing ADL under visual feedback. The regulation of stiffness is managed through the stiffness measurements of the intact upper arm, and this control takes place automatically as the amputee interacts with the environment. The position of the hand prosthesis is controlled intentionally by the amputee through the position of the shoulder, estimated using SEMG signals. This natural human-robot interface is advantageous since the impedance regulation takes place naturally without requiring amputees' attention and diminishing their functional capability. Consequently, the proposed interface does not require long training periods or interfere with the control of intact body segments and is easy to use. Details of the controller and its experimental verification are presented in Hocaoglu and Patoglu .To satisfy the design objectives, an anthropomorphic, VSA integrated, underactuated, compliant hand prosthesis is developed as follows.An antagonistic VSA is utilized to control the position and the stiffness of a four-fingered, underactuated, compliant prosthetic hand. Tendon based antagonistic arrangement is preferred since it allows for the elastic elements and actuators to be conveniently placed away from the fingers of the prosthesis. Furthermore, VSA is driven by a Bowden cable based transmission that enables motors, drivers, and batteries to be located at any suitable place on the body of the amputee. This not only results in a light-weight design but also enables easy customization of these parts, e.g., force output or battery capacity, for any user.It is well-established that an antagonistic VSA can mimic the independent stiffness and position control of a human limb joint under quasi-static conditions if the antagonistic spring elements of the VSA have nonlinear  deflection-force characteristics , the parameters required to design expanding contour are a, b, c and the spring constant k of the linear springs. It can be shown that a, b, and c are directly dependent on the maximum Smax and the minimum Smin stiffness values of the VSA as follows , the joint stiffness level is regulated to its minimum level Smin. In addition to this, when the linear springs reach their maximum stretch (xcon = xmax), the joint stiffness is regulated at its maximum level Smax.where S and θ represent joint stiffness and angle, respectively. As a result of the physical compliant elements in its mechanical design, the VSA is advantageous as it alleviates the need for force/impedance control and allows robust motion control of actuators to be utilized to achieve high performance interaction control.The position and the stiffness of the VSA are controlled through position control of Bowden cables driven by two geared DC motors. S of the VSA can be calculated asUnder quasi-static conditions , (7) and the motors are motion controlled to these values.via VSA. Several conditions are tested using the set-up shown in To experimentally verify the control performance of VSA, an antagonistic VSA is implemented using expanding contour cams shown in In Robust motion controllers implemented with high gains and at high control rates keep the motion tracking error of the motors low, indicating that the estimated stiffness and position of the pivot can be controlled with good performance, even under the high friction forces induced by the Bowden cables. While the estimated stiffness and position of the pivot can be controlled with high precision, there exist other sources of errors, such as unmodelled dynamics of the VSA  and the elasticity of the cable. The experimental results indicate that the position and stiffness tracking the performance of VSA are sufficiently high for use in a prosthetic hand, given that the position and the stiffness references will be provided in an amputee-in-the-loop fashion  and discrete reference levels are required as discussed in Section 2.2. In particular, precise control of these values is not crucial, as evidence in the literature suggests that even a few discrete  levels of stiffness can significantly improve the performance of typical manipulations  to ensure proper force distribution of the tendons. As expected, the grasp type and the motion of each finger depending on the shape of the object and the relative configuration of the prosthesis.The proposed hand prosthesis is designed to feature compliant underactuated fingers. Compliant construction results in physical flexibility of the fingers, increasing their adaptability to the environment and robustness toward impacts. Underactuated kinematics with three compliant joints per finger increases the dexterity of the hand, by allowing it to wrap around a wide variety of objects. Underactuation also enables size, weight, and cost reduction for each finger, since the actuators are typically the largest, heaviest, and most expensive components of the device.The underactuated compliant fingers are designed to mimic the closing sequence of human fingers, such that a coordinated motion of the phalanges is achieved. In particular, the stiffness of each compliant joint is adjusted such that they maintain the second and third phalanges of the finger in the fully extended configuration until the first phalanx comes in contact with an obstacle or reaches its mechanical limit. When the mechanism is free of contacts and within joint limits, it behaves like a single rigid body. When the motion of a phalanx is resisted, the force generated by the tendon overcomes the spring preload, and the adjacent phalanx initiates motion. The motion continues sequentially until movements of all phalanges are resisted, due to either contacting with an object or reaching the joint limits. Hence, each compliant finger is capable of producing many of the natural finger trajectories of a human hand, and the tendon force is properly distributed over all phalanges.The selection of appropriate material to cover the rigid phalanges and compliant joints is important to achieve robust fingers with a soft delicate touch. Selection of a high viscous silicon rubber results in high force requirements from the tendon and increases the energy consumption during bending, while the selection of a less viscous silicon rubber causes easy cracking of the material, decreasing the robustness of the finger. After testing many different materials, SILASTOSIL® 28-700 FG is evaluated to provide the best compromise among polyurethane materials to serve as the base material for the underactuated compliant fingers.Implementation of proper stiffness for the compliant joints plays a crucial role in achieving the desired coordinated motion of the anthropomorphic fingers. Phalanges are fabricated with ABS plastic through rapid prototyping, while the compliant joints are fabricated using polyurethane material. Even though the polyurethane material is proper to serve as the base material to cover the compliant fingers, including the phalanges and compliant joints, it is necessary to further adjust the stiffness of each compliant joint to implement the desired coordinated motion and to anisotropically strengthen these joints against twisting and bending. Along these lines, carbon fiber strips are embedded inside each compliant joint. Lightweight carbon fiber strips not only act as leaf springs used to implement the desired level of compliance at each joint but also help support the joints by structurally reinforcing them against twisting and undesired bending forces.Fabrication of compliant fingers consists of several stages as presented in In the second step, finger molds are used for the precise arrangement of phalanges, compliant joints, and fingers. Epoxy resin infused carbon fiber sheets are incorporated into the design as in In the third step, highly-adhesive silicone rubber is injected into the mold in its liquid form as depicted in As a consequence of injecting silicon rubber into the mold, air bubbles occur inevitably, which may cause inhomogeneous material distribution, adversely affecting the stiffness of each joint; hence, the coordinated motion of the finger. In the fourth step, degassing is implemented with –0.2 to –0.5 bar pressure to remove air bubbles from the silicone material, as presented in In the fifth step, the fingers are removed from the molds and tendons responsible for force transmission are inserted into their routes, as shown in In the final step shown in Force transmission of the compliant fingers is achieved through the flexion and the extension tendons. Due to the inherent stiffness of each compliant joint, higher forces are required while closing the fingers. To facilitate easier closing of the fingers, flexion cable channels are implemented with 120° angles, such that larger moment arms are implemented for the flexion, increasing the moments acting on the phalanges. The hand prosthesis consists of three main components: VSA, forearm, and compliant fingers. The expanding contour cams of VSA, the forearm in which the nonlinear springs of VSA are embedded on linear sliders, and device covers are fabricated through additive manufacturing, while the palm is constructed using a laser cut aluminum sheet. Since the actuators, motor drivers, and batteries of the Bowden cable driven VSA can be placed remotely anywhere on the body, e.g., can be kept inside a backpack, they are not integrated inside the prosthesis. This decision helps keep the device weight and cost low, as it provides extensive design flexibility while choosing/customizing these components according to the needs of the amputee. Sizing of the actuators should be decided considering the friction induced by Bowden cables. Note that, integration of this component into the forearm is also possible but induces challenging size and weight constraints for these components.The specifications required from the drive train are characterized as follows. The maximum force required on the drive tendon such that a 1.5 kg object can be lifted at the maximum stiffness level is verified as 160 N. The force required to close the hand at the lowest stiffness level with no object in the hand is characterized as 20 N. The maximum speed required on the drive tendon is characterized as 20 mm/s, such that all fingers reach their joint limits within 2 s when the fingers are free to move.Geared DC motors that satisfy the maximum force and speed requirements are selected to implement the drive train. With these motors, the minimum and the maximum stiffness of the drive tendon are experimentally characterized as 135 and 545 Nmm/rad, respectively. The overall weight of the device  is 1.1 kg, which is lower than the natural weight of the corresponding part of the human limb  joint is set to 0°, while the stiffness of VSA is adjusted to three distinct stiffness values that correspond to low, intermediate, and high stiffness levels for the fingers. The stiffness of the fingers is experimentally determined by applying a linearly increasing force to flex the fingers and recording their deflection.During the second task, the stiffness of the VSA is kept constant at its intermediate level, while the position of the VSA is adjusted to three distinct position values that correspond to low, intermediate, and high flexion of the fingers. The position of the fingers is determined by recording the position of the linear actuator under zero force control, while the stiffness of the fingers is determined by applying a constant force to resist flexion of the fingers at the equilibrium position and recording the resulting deflection.kl=0.091 N/mm, ki=0.17 N/mm, and kh=1.8 N/mm, respectively. The R values for these linear fits are evaluated to be higher than 0.98.R values for these linear fits are evaluated to be higher than 0.98.Experimental results provide strong evidence that the stiffness and the position of the transradial hand prosthesis can be controlled independently, with high repeatability while executing predefined tasks. The impedance characteristics of the compliant fingers of the VSA prosthesis closely match the characteristics of human fingers as presented in Howe et al. . The chaGiven that only the position and the stiffness of the driven tendon are directly regulated by the VSA, in general, the resulting position and stiffness of the fingers depending on the interaction. To test the usefulness of the variable stiffness transradial hand prosthesis, the device is attached to six volunteers, as shown in https://hmi.sabanciuniv.edu/VSA_hand_prosthesis.mp4.In particular, sEMG signals measured from the surface of the upper arm, chest, and shoulder were used to automatically adjust the stiffness level of the prosthesis to that of the upper arm, while the position regulation was intentionally controlled by the volunteers by moving their shoulder muscles. With this natural control interface, the volunteers were asked to grasp 16 objects with a wide variety of shapes  and compliance levels . Participants were asked to grasp and hold the objects for a while, then release them back onto the surface. In the same manner as in Section 3, the required stiffness level of VSA to safely grasp each object depended on the interaction. The volunteers were successful at modulating their impedance and grasping a wide variety of objects with the sEMG interface, as shown in The current prototype emphasizes simplicity, ease of use, and adaptability; hence, implements a two-degree-of-freedom underactuated power transmission to allow for the position and stiffness change of the prosthetic hand. Successful employment of the prosthesis depends on the amputee making proper decisions on how to interact with the object. Our extensive experiments with volunteers indicate that humans are very skillful at learning how to interact with the environment.On average, it took 3.2±1.3 min for a volunteer to get used to the device and successfully complete the required manipulation tasks. The time elapsed for grasping and releasing the 15 objects in the video are calculated as 1.22±0.56 s and 0.82±0.48 s, respectively. The time required to make a fist is about 2 s. The grasping performance of the proposed prosthesis prototype is comparable to commercial ones (Touch Bionics Inc., The robustness of the hand prosthesis is also tested during the user studies. During the user studies, volunteers repeatedly impacted the fingers to various surfaces. Compliant fingers made of silicon rubber and ABS material were robust to such impacts and did not sustain any damage.In the current research prototype, passive support is preferred to oppose the fingers, instead of an active thumb. This decision helps keep the system and the controller simple. Our experiences with the volunteers indicate that the passive support is adequate for implementing a wide variety of functional grasps. During post trial interviews, none of our volunteers complained about the functionality of this support.In this study, the design, implementation, and experimental evaluation of a low-cost, customizable, easy-to-use variable stiffness transradial hand prosthesis have been presented. User studies indicate that the device is dexterous enough to successfully interact with a wide variety of environments.tele-impedance control, in Hocaoglu and Patoglu (Please note that the classification of the design objectives, as presented in Section 2.1, is subjective. In general, it is up to the designer to prioritize the users' needs. Based on different prioritization of these objectives, it is possible to come up with different designs, catering to various user types. In our design, the goal has been to achieve a dexterous, anthropomorphic, adaptable, robust, low-cost mechatronic system design. Achieving such a mechatronic system design is only the half of the story toward achieving an ideal prosthesis, where the design of an easy-to-use control interface for the mechatronic system is the other half. We present such a human-machine interface, called  Patoglu .The goal of our design is to provide a fulfilling functionality to amputees through stiffness modulation while decreasing or even reversing the relatively high abandonment rate for current high-tech prosthetics. While some of the commercial devices provide many extra functions including active thumb and wrist movements, these devices require special training and long rehabilitation periods, which discourage the majority of amputees from continually using such devices. It is possible to add a thumb to the tendon driven power transmission of the proposed prosthesis; however, substantial effort is required for the intricate control of thumb orientation and stiffness, such that it becomes functional and enhances the grasping performance. Alternatively, to achieve an anthropomorphic look with an aesthetically pleasing appearance, a compliant unactuated thumb can be added to the system. Furthermore, prosthesis gloves can be worn over the transradial hand prosthesis to achieve the natural appearance of human skin.Our ongoing research study includes testing the efficacy of the variable stiffness hand prosthesis and its control interface (Hocaoglu and Patoglu, Our future study will focus on improving the anthropomorphism and functionality by the inclusion of active thumb, wrist, and auto pre-tension mechanisms to the hand prosthesis, providing a customized sizing and weight distribution of the design, evaluating the grasping performance of the hand prosthesis on the same objects by setting the stiffness of the hand to different levels, conducting comprehensive testing with larger healthy populations and also amputees to provide evidence of the effectiveness of variable stiffness actuation, and refinement of the prosthesis based on the feedback collected from amputees.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.The studies involving human participants were reviewed and approved by University Research Ethics Council of Sabancı University. The patients/participants provided their written informed consent to participate in this study.EH was responsible for the design, fabrication, and experimental evaluation of the variable stiffness hand prosthesis. VP conceived and supervised the study. Both authors contributed to the editing and scientific presentation of the article.This work has been partially supported by Tubitak Grants 219M586, 111M186, 115M698 and Marie Curie IRG Rehab-DUET.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The aim of this work was to evaluate the effects of application time of an acid mixture solution on the surface roughness, phase transformation, and biaxial flexural strength of 3Y-TZP after sintering or air abrasion. For the biaxial flexural strength measurement, 220 3Y-TZP disk-shaped specimens were prepared after as-sintering or air abrasion. The etching solution comprised a mixture of hydrofluoric acid, sulfuric acid, hydrogen peroxide, methyl alcohol, and purified water. The samples were divided into 11 subgroups according to the etching times . The results showed that acid treatment on both as-sintered and air-abraded 3Y-TZP surfaces increased the surface roughness. However, it had no significant effects on the monoclinic phase or flexural strength of as-sintered zirconia. The monoclinic phase and flexural strength of air-abraded zirconia increased sharply after air abrasion; however, they gradually decreased after acid treatment, to a similar level to the case of the untreated surface. Surface treatment with acid mixture increased the roughness, but the lack of increase of monoclinic phase is thought to be because the loose monoclinic particles remaining on the surface were removed through the etching process. For many years, the metal ceramic crown has been the most commonly used dental crown in aesthetic prosthetic restoration. However, its use has recently declined owing to problems such as its metal framework color, having an opaque shade compared to natural teeth, and patient metal allergies ,2. RecenAlthough zirconia is chemically and biologically inert, predictive bonding with zirconia is difficult to achieve in clinical applications ,12. SurfOther studies reported that creating surface roughness using air-abrasion methods on zirconia surfaces is useful and yields good results in bonding; nevertheless, this technique has several limitations. Firstly, air abrasion can cause stress-induced transformation of zirconia ceramics ,19. StabAcid treatments have also been attempted to roughen the material surface and improve the bond to resin cement or porcelain. Surface etching using hydrofluoric acid has mainly been performed on glass ceramics. This approach removes the silica-containing glassy matrix and exposes the crystalline phase ,32. HoweIn order to increase the mechanical interlocking between luting agents or veneered porcelain and zirconia surfaces and to achieve an efficient performance of predictive dental restoration, it is essential to minimize the damage of zirconia surfaces and to increase their roughness, while maintaining their strength and tetragonal phase. The purpose of this study was therefore to evaluate the effects of acid mixtures containing hydrofluoric acid, sulfuric acid, hydrogen peroxide, and other compounds on the surface roughness, phase transformation, and biaxial flexural strength of 3Y-TZP after as-sintering or air abrasion. The null hypothesis of this study is that neither etching using acid mixture nor the combination pretreatment with air abrasion and etching significantly influences the biaxial flexural strength of zirconia surfaces.3 and a purity of >99%  specimens were milled  in a pre-sintered state. The fabricated specimens were sintered according to manufacturer guidelines. The final dimensions were obtained with disk-shaped specimens having a 15-mm diameter and a 2-mm thickness after sintering. Then, the surface was uniformly polished using SiC abrasive paper up to 1200 grit. As outlined in For the biaxial flexural strength measurement, 220 3Y-TZP with a density of 6.08 g/cmAs-sintered zirconia group: The specimens were sintered and then surface-treated by acid etching. The etching solution comprised a mixture of 25% hydrofluoric acid, 16% sulfuric acid, hydrogen peroxide, methyl alcohol, and purified water. For the preparation of the etching solution, hydrofluoric acid: sulfuric acid: catalyst: methyl alcohol was mixed in a volume ratio of 7:5:1:2, and the preparation was completed by mixing the etchant composition and purified water at a ratio of 1:1. After heating the etching solution to 80 °C, surface treatment was performed on the zirconia specimen. This group was divided into 11 subgroups (n = 10 each) according to etching time .Air-abraded zirconia group: After sintering was completed, the specimens of this group were subjected to air abrasion at a distance of 10 mm and 0.3 MPa of pressure using aluminum oxide particles. The surface was treated by acid etching using the same etching solution. Air abrasion was applied to all specimens using the same technique. This group was likewise divided into 11 subgroups (n = 10 each) according to etching time .For each specimen group, data were measured  five times to obtain the surface roughness data. The average of the data was obtained using calculation software based on the data peaks and valleys. The arithmetic mean (Ra) data were thereby obtained.The phase transformation by the surface treatment of each group was analyzed by measuring the peak intensity ratio of the zirconia specimens using a high-resolution X-ray diffractometer  under Cu-Kα (1.54 Å) irradiation, 45 kV, 200 mA, 20–90°, and a 0.02° step size. The monoclinic peak intensity ratio (Xm) was calculated by the method described by Garvie and Nicholson , as follThe surface morphology was observed and analyzed using field-emission scanning electron microscopy . The specimens were analyzed under high vacuum at 5 kV and observed at 20,000× magnification.In accordance with ISO 6872, biaxial flexural strength tests were performed on a universal testing machine  using the piston-on-three-ball technique. Three 5-mm-diameter stainless steel balls were arranged to form a support circle with a diameter of 12 mm and an angle of 120° to each other. The specimen was placed exactly in the center. The load piston was applied (1.4-mm diameter) at a crosshead speed of 1.0 mm/min. The fracture load of each specimen was measured, and the biaxial flexural strength was calculated according to the following formula:P is the fracture load (N), and h represents the thickness of the disk at the fracture origin (mm). X and Y are determined by the following formula:u is Poisson’s ratio (0.25), r1 is the radius of the support circle, r2 is the radius of the load piston, and r3 is the specimen radius.Here, FS denotes biaxial flexural strength (MPa), σ0) and Weibull modulus (m) were calculated according to Equation:fP is the probability of failure (between zero and one), σ is the flexural strength in MPa, and σ0 is the Weibull characteristic strength in MPa (63.2% of specimen failure).The Weibull characteristic strength . All statistics were analyzed using statistical analysis software .Shapiro–Wilk’s test and Levene’s test were performed to confirm data normality and variance homogeneity. Surface roughness and biaxial flexural strength values were analyzed using one-way ANOVA and the post-hoc Tukey–Kramer test (α = 0.05). A paired p < 0.001). After 15 min, the roughness was approximately 0.2 µm, which is similar to that of the surface after air abrasion. In the air-abraded zirconia specimens, there was no significant change in roughness at the beginning of the application of the etching solution. However, the roughness increased after 10 min (p = 0.016) and showed a roughness average (Ra) value of more than 0.3 µm after 20 min (p = 0.016). The roughness of the air-abraded zirconia samples was high at all times. It was confirmed that the Rz value also showed a tendency to increase as the etching time increased, similar to Ra.The zirconia surface roughness data following the pretreatment method were obtained using surface profiler equipment, as shown in 2 were observed on the as-sintered zirconia surface  in the region of 2θ = 30° significantly increased to 0.55. The FWHM shows a unique finding, i.e., the width gradually decreased with an increase in the etching time.t and (110)t. However, as the etching time increased, they recovered to the same shape as those without air abrasion (The air-abraded zirconia control specimens showed a reversed intensity of peaks (002)abrasion B. With rabrasion . After 1The XRD pattern with diffraction degree ranging from 20 to 90 degrees and the XRD pattern with the y-axis scale changed to logarithmic are presented in the supplement information .p = 0.086). A flexural strength in the range of 946.4–1062.0 MPa was evident.The biaxial flexural strengths of the as-sintered and air-abraded zirconia groups in accordance with etching times are shown in The air-abraded zirconia samples that were not subjected to etching showed a high flexural strength of 1438.1 MPa. However, as the etching time increased, the flexural strength gradually decreased. The flexural strength of the air-abraded zirconia samples subjected to etching for more than 12 min showed no significant difference compared to that of the as-sintered zirconia samples subjected to etching for 12 min.In the as-sintered zirconia group, there was no significant correlation between the Weibull modulus (m) and Weibull characteristic strength (σ0) according to the etching time. However, in the air-abraded zirconia group, the Weibull modulus increased in the 20 and 30 min etching groups, and the Weibull characteristic strength (σ0) value continuously decreased with the etching time .p < 0.001).The weights of as-sintered zirconia and air-abraded zirconia were evaluated before and after the etching process . Before In this study, the effects of acid mixtures containing hydrofluoric acid, sulfuric acid, hydrogen peroxide, and other compounds on the surface roughness, phase transformation, and biaxial flexural strength of as-sintered and air-abraded 3Y-TZP were evaluated. The etching process using acid mixtures increased the surface roughness of both as-sintered and air-abraded zirconia groups. However, the as-sintered zirconia samples showed a slight increase of monoclinic-phase contents, even when the etching time was increased. On the other hand, in the air-abraded zirconia group, the monoclinic phase was greatly increased owing to the t-m phase transformation after air abrasion, and it decreased during the etching process. Similarly, in the case of the as-sintered zirconia samples, the biaxial flexural strength did not change significantly as the etching time increased. On the other hand, in the air-abraded zirconia group, the biaxial flexural strength markedly increased immediately after air abrasion. After 20 min of etching, the flexural strength decreased significantly compared to the samples subjected to air-abrasion only. These results show that the hypothesis of this study was rejected.The SEM results of the surface treatment method and etching time showed that after acid treatment, the grains of the zirconia samples became highly irregular and the grain size decreased for both the as-sintered and air-abraded zirconia specimens. Since the crystal boundary was more chemically reactive and dissolved faster, it is believed that irregular grooves formed around the crystal and the grain size was reduced . MoreoveThe roughness of the zirconia specimens continued to increase in both as-sintered and air-abraded zirconia. However, it is known that sulfuric acid or hydrogen peroxide among the components of the acid mixture does not significantly increase the roughness ,50. Prevt broadened in the 2θ = 30° region; finally, a reversal in the intensities of peaks (002)t and (110)t was observed. In addition, the monoclinic phase volume increased by 12.09%.The XRD findings of the air-abraded zirconia control group in this study corroborated the findings of previous studies that reported the three characteristics that appear after the air-abrasion surface treatment of zirconia samples : first, t, and the peak reversal disappeared in (002)t and (110)t regions, all of which were unique features not previously observed in other studies. Similar findings of regeneration firing, i.e., reverse transformation, were reported in previous studies. Regeneration firing was primarily observed when thermal annealing was performed in furnaces at temperatures above 900 °C for manufacturing zirconia [However, as the etching time increased in the air-abraded zirconia specimen, the monoclinic phase contents decreased, the FWHM decreased in tetragonal peak (111)zirconia ,52. The zirconia ,52. Simizirconia . In the zirconia .On the other hand, Ding et al.  showed tIn the as-sintered zirconia group, a monoclinic volume of 3.08–6.02% was observed depending on the etching time. Nonetheless, it was not statistically significant and was very small compared to the values reported in other studies. This result is very similar to that of Xie et al. , who rep2O3 particles significantly increased the Y-TZP flexural strength through transformation toughening. In addition, many researchers have published studies supporting the increase in flexural strength when air abrasion is performed on zirconia surfaces [Various studies were conducted on the effect of air abrasion on the zirconia flexural strength with alumina oxide particles. Chintapalli et al.  reportedsurfaces ,40,42. IOn the other hand, the control group of air-abraded zirconia showed the highest flexural strength, which then gradually decreased as the etching progressed. Iijima et al.  similarlIn addition, the hydroxyl (OH) group generated by treating hydrofluoric acid with zirconia could penetrate the Y-TZP surface stress zone to increase lattice spacing and accelerate low-temperature degradation (LTD) . In thisIn this study, the effects of acid mixture on the as-sintered and air-abraded 3Y-TZP surfaces were investigated in terms of respective topography, XRD, and biaxial flexural strength analyses of the surfaces. Surface roughness increased in accordance with etching time in all groups. In the XRD and biaxial flexural strength analyses, the etching effect on the as-sintered zirconia was weak, while the monoclinic phase contents and flexural strength decreased for the air-abraded zirconia. Nevertheless, this study has some limitations. Because only one acid-mixture combination was used in this study, and the zirconia surface was not analyzed based on the acid concentration difference or acid-mixing ratio. In addition, the effects of LTD through the aging process and acid etching for longer than 30 min were not confirmed. To confirm the long-term clinical performance of the zirconia prosthesis and to reach a more definitive conclusion, it is necessary to study the effects of LTD and to analyze the effects of various parameters of the acid mixture and longer acid treatment.Surface treatment using acid mixture on both as-sintered and air-abraded 3Y-TZP surfaces further increased the surface roughness.Surface treatment using acid mixture of the as-sintered zirconia surface produced a slight increase of the monoclinic-phase contents. On the surface of air-abraded zirconia, the monoclinic phase content increased considerably after air abrasion; however, the removal of loose monoclinic particles was occurred with the increase in acid treatment time.Surface treatment using acid mixture of the as-sintered zirconia surface did not significantly affect the biaxial flexural strength. The flexural strength of the air-abraded zirconia surface increased significantly; however, as the acid treatment time increased, the biaxial flexural strength gradually decreased to almost the same strength as that of the untreated surface.Considering the study limitations described above, the following conclusions were drawn:Therefore, it was confirmed that surface treatment of as-sintered zirconia and air-abraded zirconia samples with acid mixtures increased the surface roughness of the zirconia samples without adversely affecting their flexural strength. Surface treatment with acid mixtures may thus be helpful in clinical applications involving the use of zirconia surfaces with luting agents or veneered ceramics.


The Editors decided to retract this paper to avoid further damage to the scientific community.The Brazilian Journal of Medical and Biological Research remains vigilant to prevent misconduct and reinforces the Journal’s commitment to good scientific practices. We regret the unprofessional behavior of the authors involved.zhangweiwei3832@126.com>Correspondence: Weiwei Zhang: <


We are now approaching the end of the second year of the coronavirus disease 2019 (COVID-19) pandemic, and we are still living differently from our usual lives. We have had to make adaptations to our working, teaching, research and our interactions with colleagues, friends and families. Everyone has made sacrifices, some more than most, as we learn to navigate the travails of this pandemic. This year has been as difficult as 2020 with two waves of the virus. Having said that, it is important to remember that we can be vaccinated against the virus, and that the more people there are who are vaccinated, the more control of the pandemic there will be.Despite the difficulties that we are all experiencing, the journal has continued to thrive. For this, we are thankful to our authors who keep the submissions rolling in, our reviewers who do a sterling job in carefully considering the merits and the issues in the submissions, and our publishers who keep the publication process on track.We are delighted to welcome Prof. Verusia Chetty from the University of KwaZulu-Natal as our new Associate Editor. Prof. Josè Franz is taking a well-earned rest after many years at the helm of our journal.Again, I am glad to report that we are receiving submissions from an increasingly wide range of authors from South Africa and other countries. In addition, we have accepted several articles from other healthcare professionals who have submitted articles relevant to our profession. I hope that this trend persists as it means that our journal has much broader appeal. We are also publishing a special edition this year namely, ‘Spinal Deformities – Evidence and Patient Safety in Management’ from a group of international researchers who work in the management of spinal deformities.there is a need for our assessments and interventions to be appropriate and context specific for our many communities that have such stark -socio-economic and cultural differences (paraphrased). These changes to the way in which we manage our patients should be grounded in appropriate studies that determine the effectiveness of interventions that take into consideration the cultural, socio-economic and geographical context of our patients. How can the relatively few physiotherapists in South Africa contribute meaningfully to our total population requiring our expertise? Should we be considering more home programmes, more involvement of the families and caregivers of patients with long-term disabilities, more use of telemedicine and task shifting to name but a few ways of managing patients appropriately in our environment. These are the questions and issues that I hope our researchers and clinicians start considering as we always seek to ensure that we are providing healthcare that is appropriate and relevant to our own population. I hope to see increasing numbers of submissions to our journal that reflect our researchers’ efforts to modify our interventions so that we ensure that our expertise gets to our population that needs it most. This is a worthwhile challenge and one, which I believe our researchers and clinicians need to engage in.Prof. Saul Cobbing from the University of KwaZulu-Natal made an important point in his state-of-the-art article published this year Cobbing : there iSouth African Journal of Physiotherapy is going from strength to strength; but to keep improving we need good quality submissions, careful reviewers and continual improvement of the publication systems. The South African Society of Physiotherapy financially sponsors our journal, which is an enormous contribution to its viability. We have a unique opportunity to develop the journal even further as we publish studies that grapple with the given issues and that provide appropriate answers to ensure the relevancy of our profession within our South African healthcare sector.The Our best wishes for 2022 with the hope that the new year does indeed bring some relief from the COVID-19 pandemic. Editor-in-ChiefSouth African Journal of PhysiotherapyProf. Aimée Stewart


Xanthosoma sagittifolium), as an unconventional source of starch, was evaluated using the hydrothermal treatment of autoclaving. The physicochemical characterization of RS3 made from malanga flour was carried out through the evaluation of the chemical composition, color attributes, and thermal properties. In addition, the contents of the total starch, available starch, resistant starch, and retrograded resistant starch were determined by in vitro enzymatic tests. A commercial corn starch sample was used to produce RS3 and utilized to compare all of the analyses. The results showed that native malanga flour behaved differently in most of the evaluations performed, compared to the commercial corn starch. These results could be explained by the presence of minor components that could interfere with the physicochemical and functional properties of the flour; however, the RS3 samples obtained from malanga flour and corn starch were similar in their thermal and morphological features, which may be related to their similarities in the content and molecular weight of amylose, in both of the samples. Furthermore, the yields for obtaining the autoclaved powders from corn starch and malanga flour were similar (≈89%), which showed that the malanga flour is an attractive raw material for obtaining RS3 with adequate yields, to be considered in the subsequent research.The feasibility of obtaining resistant starch type III (RS3) from malanga flour ( Xanthosoma sagittifolium L. Schott) is the common name for one of the most popular and widely consumed aroid cultivars. The other names for this corm include yautia, taioba, tanni, or new cocoyam, depending on the country of origin [Malanga ; and RS4, which is obtained by the chemical modification of native starch [Most of the native starch is completely digested and absorbed in the small intestine; however, a small fraction of the starch, known as resistant starch (RS), cannot be hydrolyzed to free glucose, since it resists the hydrolytic attack of digestive enzymes . RS arricer risk ,11. RS ie starch . RS is ce starch ,12,13. Ae starch . RS3 doee starch ,17,18,19Several studies have been published on obtaining resistant starch type-III (RS3) from corms and tubers starches, such as taro starch , purple p < 0.05) in the protein, lipid, and total dietary fiber contents. MF had a protein content (≈2.8%) that was 1.5, 3, and 7 times greater than AMF, CS, and ACS, respectively. Cocoyam flours have been reported as a poor source of protein, with values ranging from 7.5 to 2.1% [The chemical composition of malanga flour (MF), corn starch (CS), and their respective resistant type III starches  and autoclaved corn starch (ACS)) are shown in content ≈.8% that  to 2.1% .The moisture contents of MF (15.65%) and CS (14.36%) were higher than other studies reported for malanga flours (8.87 to 10.67%) . The abop > 0.05) in the ash content, although the ash content values were high (6%), suggesting that they may have significant amounts of the above elements. The phosphorus content is important in the functional properties of starches, and their content is mainly attributed to the presence of ester phosphate groups [MF and AMF showed no significant differences  of the samples are presented in soma sp. ,24,35,36soma sp. ,37,38.Xanthosoma sagittifolium) from white and red flesh, which was 63.47 and 69.16%, respectively, and similar to taro flour (Colocasia esculenta L. Schott) from different varieties, ranging from 82.1 to 86.6% [p > 0.05) on the TS content of MF and CS samples after the autoclave treatment, while the AS content decreased at 14.16 and 9.96% in MF and CS, respectively. The apparent amylose content and the average amylose molecular weight (p < 0.05) by the hydrothermal treatment. The reduction in amylose molecular weight is consistent with the decrease in AS content , available starch (AS), resistant starch (RS), and retrograded resistant starch (RRS) are shown in to 86.6% . There wr weight  were sig content a and the content b. The diThe indigestible fractions of starch (RS and RRS) are shown in The color attributes lightness (L*), chroma (C*), and hue angle (°h) of MF, CS and their respective autoclaved powders are shown in o = 75.14 °C), peak temperature (Tp = 84.56 °C), conclusion temperature (Tc = 92.03 °C), and enthalpy change (ΔH = 12.49 J/g) of gelatinization, compared to the CS sample , and Hoyos-Leyva et al. [Colocasia esculenta and Xanthosoma sagittifolium varieties (Tp = 80.6–84.8 °C). p > 0.05) between them in any of the thermal variables analyzed, but they presented higher values of To, Tp and Tc compared to their corresponding native sample, CS and MF, respectively. The results indicate that these native samples, when subjected to the hydrothermal process of autoclaving with high pressure, apparently lose their native granular structure, giving rise to structures with greater thermal stability. Shah et al. [o, Tp and Tc parameters.Differential scanning calorimetry (DSC) is used to monitor changes in thermal energy, associated with physical and chemical transformations of materials, as a function of temperature. The results of the thermal analysis of the samples are presented in S sample . The Tp z et al.  for cocore Tc = 9.03 °C, ah et al.  reportedn = 1/λ) of 3400, 2929, 1500, 1600 and 620–527 cm−1, which correspond to the functional groups of poly-OH, -CH2, C–O–C , carboxylate ion (COO−), and skeletal modes of the pyranose ring structure, respectively [−1, which evidenced the breakdown of the glycosidic bond caused by the high temperature and pressure of the autoclave treatment.The FTIR analysis performed on the samples is shown in ectively ,15,38. A−1) in MF, probably due to other minor components, mainly fibers and some plant pigments. The samples submitted to the autoclaved treatment, ACS and AMF, showed similarities in the position of some characteristic peaks. The differences between the sources of RS3 that are consist with an extension of the peaks located at 3400 cm−1 suggest an increase in the crystalline region, as reported by Garcia-Rosas et al. [s et al.  and Shahs et al. .Xanthosoma sagittifolium) was obtained using the dehydration of corms from plants cultivated in the municipality of San Fernando . Corms were washed, disinfected with water and soap, and their shells were removed and cut into slices with a 5 mm thickness. The slices were placed in a 5% citric acid solution for 15 min, subsequently placed in trays, and underwent a conventional drying process for eight hours at 60 °C. The dried slices were ground and sifted with a mesh number 80, and the flour obtained was vacuum packed. All the chemical reagents used were analytical grade and were acquired from Sigma-Aldrich .Commercial corn starch  was acquired at a local market . Malanga flour  and corn starch (CS) to obtain autoclaved malanga flour (AMF) and autoclaved corn starch (ACS) powders rich in retrograded resistant starch (RRS), according to the method used by Berry . First, The chemical composition of samples comprised the determination of crude protein (N × 6.25) (method 954.01), total lipid (method 920.39), moisture content (method 934.01), and ash content (method 942.05) using the official procedures of the AOAC . In addiv/v) for 24 h. The samples were washed with ethanol and recovered by filtration. The affinities of defatted starches to the iodine reagent were measured using an automatic potentiometer . The apparent amylose content was determined by dividing the iodine affinity of defatted starches by 20%, as reported by Takeda and Hizukuri [Apparent amylose content was determined by the method reported by Espinosa-Solis et al. . SamplesHizukuri . The anaThe color of native and modified samples was evaluated according to the methodology reported by Flores-Peña et al.  using a The thermal properties of the samples were determined with a differential scanning calorimeter (DSC)  according to the procedure described by Paredes-Lopez et al. . Two mg The morphology of the starch granules was evaluated by scanning electron microscopy (SEM). A JEOL microscope was used . The powders samples were attached to a double-adhesion graphite tape in a metal sample holder and covered with a layer of gold to make it conductive. Finally, under the microscope, images were taken at an acceleration potential of 10 kV.® Plus, Bayer de Mexico, S.A. de C.V.). The TS content was calculated as glucose (mg) × 0.9, using potato starch as a reference. The analysis was performed in triplicate for each sample.Total starch (TS) content was determined under the method reported by Goñi et al. . For thiAvailable starch (AS) was determined according to the method reported by Holm et al. . Five huFor the determination of resistant starch (RS) content in the samples, the methodology described by Goñi et al. was performed . This teg, discarding the supernatant, and the pellet was washed with ethanol and acetone. Finally, the pellet was re-suspended with 2 M KOH and incubated with amyloglucosidase, and centrifuged for 15 min at 3000× g, and the supernatant was collected. Fifty µL of supernatant was taken to determine glucose content using the GOD/POD test, reading the optical densities of the samples at 510 nm.The determination of retrograded resistant starch (RRS) followed the methodology described by Saura-Calixto et al. . One hun6, 3.8 × 105, 1.8 × 105, 1.0 × 105, 4.8 × 104, and 1.2 × 104 g/mol). Amylose was isolated from native and modified malanga flour and corn starch following Torruco-Uco et al. [The weight-average molar mass of amylose was determined by HPSEC-RI, for this purpose, a calibration line was obtained using pullulan standards of various molar masses  within the mid-infrared. An average of 34 sweeps per sample was recorded with a resolution of 4 cm−1 in the region of 400 to 4000 cm−1. The molecular spectral data of samples were collected and corrected with the air background and further analyzed with Spectrum Two software version 10.4. The analysis was performed in triplicate for each sample. Spectral analysis of each of the samples was selected. Therefore, the reported spectra are representative of each of the individual samples.The FTIR analysis of the samples was performed according to the methodology recently reported by Tirado-Gallegos et al.  using a p ≤ 0.05) was used to apply the SigmaStat statistical program, version 2.03 [p ≤ 0.05) [The experiments were conducted using a completely randomized design. A one-way variance analysis  .The physicochemical, morphological, and FTIR analyses showed, in the malanga flour, the presence of minor components other than the starch. These components influenced the color and thermal properties of the malanga flour and its respective autoclave samples. The autoclaving treatment modified the physicochemical, morphological, and thermal properties, which were similar in both of the native samples . The autoclaving treatment increased the RS and RRS contents in the malanga flour. These results potentiate malanga flour by obtaining food with the content of dietary fiber and mineral salts practically equal to that of native flour, and with a greater presence of RS, proteins, and lipids than that observed in native and resistant starch from a commercial source, such as corn starch. Malanga flour can be considered as a feasible raw material for obtaining resistant starch type III (RS3), with physicochemical, morphological, and thermal properties similar to RS3 obtained from commercial corn starch.


Newly developed graft failure negatively affects the short- and long-term outcomes of patients who experience coronary artery bypass grafting (CABG) surgery. This study explored the value of transit time flow measurement (TTFM) parameters for predicting the risk of newly developed graft failure that occurs within 1 year after CABG, as well as investigated the relationship between newly developed graft failure and adverse cardiovascular events.A total of 134 patients who underwent CABG and had CT angiography (CTA) data (1 year post-operatively) were divided into two groups: the patient group, in which patients did not have newly developed graft failure, and the occluded group, in which patients developed newly developed graft failure between 1 and 12 months after CABG. The patency rate of grafts in different targets was analyzed. The correlations between graft failure and TTFM parameters and between graft failure and the occurrence of adverse cardiovascular events were investigated.P = 0.007), a lower mean graft flow (MGF) , and a lower diastolic flow fraction (DF)  than the patent group. The cut-off value for predicting newly developed graft failure was PI > 2.75 (P = 0.007), MGF < 23.5 ml/min (P = 0.03), and DF < 65.5% (P = 0.019). Compared with the patent group, the newly developed graft failure group had higher rates of recurrent angina  and revascularization intervention (9.1 vs. 0% P = 0.026). However, there were no differences in death, cardiac death, myocardial infarction, and cerebral infarction after CABG operation between these two groups (P > 0.05).The overall rate of newly developed graft failure was 7.2%, the venous graft failure was 10.8%, and the arterial graft failure was 0.7%. The occluded group had a higher pulse index (PI) (2.9 vs. 2.4, A high PI and low MGF and DF are risk factors for newly developed graft failure. The patients with newly developed graft failure had higher rates of recurrent angina and revascularization intervention. TTFM parameters may be used to predict the occurrence of newly developed graft failure in patients after CABG surgery. The first coronary artery bypass graft surgery in patients with coronary heart disease in 1961 was carried out by Robert Goetz . HoweverTransit-time flow measurement (TTFM) is a fast and reliable technique for the intraoperative evaluation of grafts and is thus frequently applied during CABG . The valThis study investigated the predictive value of TTFM parameters for newly developed graft failure occurring within 1 year after successful CABG, as determined by CTA, and investigated the relationship between newly developed graft failure and adverse cardiovascular events (ACEs) during postoperative follow-up.Data of patients who underwent isolated CABG were retrospectively collected between July 1, 2018, and December 31, 2019, from the database at Qingdao Municipal Hospital Affiliated with Qingdao University. A total of 176 patients underwent CABGs. Among these patients, 14 with no CTA data and 28 who developed graft failure before discharge were excluded from this study. Hence, this study enrolled a total of 134 patients, who were divided into two groups: the patent group, which was defined as having patent anastomoses, and the occluded group, which included newly developed graft failure defined by at least one occluded anastomosis. The Institutional Review Board and Ethics Committee at our hospital approved the study protocol. Informed consent from patients was waived owing to the retrospective nature of this study. The use of data at the time of operative consent was approved.Coronary artery bypass graft surgery (CABG) was performed on all patients through a median full sternotomy. A tissue stabilizer  was used to stabilize the target coronary arteries. An intra-coronary shunt  was used during off-pump CABG. In on-pump CABG, cardiopulmonary bypass was generated following standard cannulation of the ascending aorta and cavo-atrial cannulation. The surgeon measured each bridge first, and when the patient's blood pressure was relatively stable at (90–120)/(70–90) mmHg and did not require circulatory support or medication, the blood pressure was measured three times, and the average was used for this study. All distal anastomoses were carried out after cardiac arrest.The VeriQ system TTFM device  was used to measure TTFM parameters, which included the diastolic flow fraction (DF), the pulse index (PI), and the mean graft flow volume (MGF). The criteria for assessment of satisfactory blood flow parameters were as follows: the morphology of the blood flow waveform was reproducible and stable; MGF > 15 ml/min and PI < 5. If a sufficient graft flow was not obtained, grafts were revisited to rule out technical complications. In latter cases, the TTFM parameters that were collected at the last measurement were used.Patients who underwent CABG without contraindications underwent cardiac CTA before discharge. The location, number, and patency of bypass grafts were assessed using Axial, 3D multi-planar, and volume-rendered reconstructed images. Two radiologists assessed graft patency. An occluded graft was defined as one that had no visualization or had visualization as a stump-like structure. CTA was rechecked 4–25 days after surgery and before discharge. The median CTA after surgery was 15 days, and the median of CTA postoperative recheck was 382 days.Adverse cardiovascular events (ACEs) included recurrent angina, revascularization intervention, cardiac death, myocardial infarction, and cerebral infarction.U-test between two groups. Pearson's χ2 test or Fischer's exact test was used to comparing binary data as appropriate. Uni-and multi-variate models using Logistic regression and odds ratios (ORs) were used to analyze the TTFM parameters to define the independent predictors of risk of graft failure. The optimal cutoff values of PI, MGF, and DF were determined using the receiver operating characteristic (ROC) curve to predict newly developed graft failure. A P < 0.05 was considered statistically significant. All analyses were performed with SPSS version 23  and GraphPad Prism 5 .Abnormally distributed continuous variables are presented as the median and interquartile range (IQR). Nominal and categorical variables are expressed as proportions (%) and absolute numbers. Numerical data were compared using the Mann–Whitney P = 0.03).A total of 134 patients were included in this study. Among these 134 patients, 22 (16.41%) had newly developed graft occlusion within 1 year after CABG. Demographic and baseline clinical characteristics of patients in both the patent and the occluded groups are shown in P > 0.05; In addition, there were no differences in baseline procedural characteristics and postoperative complications between the patent and occluded groups (P = 0), and that the failure rate of the composite graft was significantly higher than that of arterial graft . Additionally, the patency of the venous graft in the circumflex and right coronary system was worse than that in the anterior descending system.Detailed results of CTA examination 1 year after CABG are shown in P = 0.007), a lower MGF , and a lower DF  than the patent group. ROC curve analysis showed that the cut-off value for predicting the overall newly developed graft failure was a PI > 2.75 (P = 0.007), a MGF < 23.5 ml/min (P = 0.03), and a DF < 65.5%  and re-vascularization intervention (9.1 vs. 0% P = 0.026). However, there were no differences with regard to death, cardiac death, myocardial infarction, and cerebral infarction after operation between these two groups  surgery is the most frequently performed procedure worldwide . HoweverIn our center, CTA examination is routinely performed postoperatively on patients to determine if any newly developed graft failure 1–12 months after CABG. In the present study, we investigated the predictive value of TTFM parameters for newly developed graft failure occurring within 1 year after successful CABG, as determined by CTA, and investigated the relationship between newly developed graft failure and ACEs during postoperative follow-up. We excluded patients with grafts that failed before discharge. We found that the overall newly developed graft failure was 7.2% and that the venous graft failure was 10.8%, which were consistent with the results reported in previous studies , 19. HowSome clinical studies have suggested that TTFM is a useful technique to evaluate graft function following CABG . HoweverWe reported in this study that the overall rate of newly developed graft failure between 1 and 12 months after CABG was 7.2%, the venous graft failure was 10.8%, and the arterial graft failure was 0.7%. A high PI and low MGF and DF are risk factors for newly developed graft failure. Patients with newly developed graft failure have higher rates of recurrent angina and re-vascularization intervention. Our findings suggested that TTFM parameters may be used to predict the occurrence of newly developed graft failure in patients after CABG surgery.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.ZL conceived the study and participated in its design and coordination. YQ, WS, and YC helped to draft the manuscript. All authors have read and approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. 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