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This paper proposes a novel modular cable-driven humanoid arm with anti-parallelogram mechanisms (APMs) and Bowden cables. The lightweight arm realizes the advantage of joint independence and the rational layout of the driving units on the base. First, this paper analyzes the kinematic performance of the APM and uses the rolling motion between two ellipses to approximate a pure-circular-rolling motion. Then, a novel type of one-degree-of-freedom (1-DOF) elbow joint is proposed based on this principle, which is also applied to design the 3-DOF wrist and shoulder joints. Next, Bowden cables are used to connect the joints and their driving units to obtain a modular cable-driven arm with excellent joint independence. After that, both the forward and inverse kinematics of the entire arm are analyzed. Last, a humanoid arm prototype was developed, and the assembly velocity, joint motion performance, joint stiffness, load carrying, typical humanoid arm movements, and repeatability were tested to verify the arm performance. [ABSTRACT FROM AUTHOR]

Late Paleozoic tectonic evolution of northeastern China is complicated by the interaction of the Central Asian Orogenic belt development and the initiation of subduction from the Pacific Ocean plate along the eastern margin of Asia. In this study, we elucidate this problem by collecting new geochemical and geochronological data from late Paleozoic bimodal igneous rocks from the eastern margin of the Jiamusi block. By LA–ICP–MS zircon U–Pb dating, the 206Pb/238U age of the granitoid sample is 313–279 Ma, and the diabase 206Pb/238U age is 298–276 Ma. Rock geochemical studies show that diabase and granitoid have obvious chemical differentiation characteristics, indicating that they are the products of non-homologous magmatic evolution. Zircon Lu–Hf isotopes indicate that diabase magma originates from the metasomatism of the mantle wedge by subducting oceanic crust melts, granitoid magma mainly comes from the lower crust and the new crust. Our results together with a synthesis of existing data show that bimodal magmatism occurred in the study area from the Late Carboniferous to Early Permian when the Jiamusi block was an active continental margin and in a stretching background. Our synthesis of the existing data places our new data into a regional tectonic framework, and our proposed tectonic model provides the following new insights: (1) the northward expansion of the Paleo-Tethys Ocean from the Late Carboniferous to the Early Triassic led to the overall northward drift of the Paleo-Asian Ocean and the Xing'an-Mongolian Orogenic belt, which marks the easternmost segment of the Central Asian Orogenic belt, (2) the Paleo-Asian Ocean continued Late Permian–Early Triassic subduction caused back extension that rifted the Jiamusi and Songnen blocks apart and formed the Mudanjiang Ocean. [ABSTRACT FROM AUTHOR]

Deep space exploration can satisfy humanity's curiosity about the origin of life and the evolution of the universe and enhance our understanding of the internal geological structure and climate change of extraterrestrial bodies. The most direct way to explore extraterrestrial bodies is to sample and analyze the regolith. Drilling is the most effective sampling method, and extraterrestrial regolith drills have helped humans acquire many samples in planetary exploration. Developing high applicable and flexible ERDs for extraterrestrial regolith penetration and sampling has attracted strong attention from scientists and engineers worldwide. This paper presents a detailed review of extraterrestrial drilling technologies. Firstly, the particularities of extraterrestrial drilling are introduced. Then, the ERDs utilized in previous planetary exploration missions and the latest advances are reviewed in detail, including the categories, historical context, and (dis)advantages. Next, the general characteristics of extraterrestrial drilling are summarized, including the mainstream approaches to studying the drilling mechanics and thermophysics. Then, the critical technologies of ERDs, from a conceptual design to a practical prototype, are analyzed in depth. Finally, the prospects for extraterrestrial drilling technology are presented, including water ice drilling, long tunnel boring, deep drilling, and intelligent drilling. [ABSTRACT FROM AUTHOR]

In this paper, the influence of different opening ratios and different opening directions of the windows on the natural smoke exhaust was studied through a series of real fire experiments and simulation analysis. Increasing the open area of the window could effectively improve the overall smoke exhaust effect. When the top windows were open and the opening ratio increased from 19.2% to 24.3%, the optical density was decreased by 12.4%. The average smoke exhaust rate per unit area of the window did not change significantly. Increasing the area of the natural smoke exhaust window could effectively increase the smoke exhaust rate and improve the overall effect of smoke extraction. When the top windows were open, the temperature rise on the top floor was 30.8%–47.5% lower while the visibility was 16.8%–21.9% higher than that when the side windows were open. [ABSTRACT FROM AUTHOR]

The clinical symptoms of perforating arteries differ, and responses to intravenous thrombolytic therapy are heterogeneous. Here, we investigated the effect of intravenous thrombolytic therapy and the related factors influencing acute perforating and non-perforating middle cerebral artery infarctions. We analyzed 320 patients with acute middle cerebral artery infarction who received alteplase thrombolysis within 4.5 h of onset at two stroke centers from January 2016 to December 2019. Outcome measures included rates of a favorable functional outcome (modified Rankin Scale scores of 0–2), distribution of modified Rankin Scale scores, intracranial hemorrhage, and symptomatic cerebral hemorrhage at 14 days, with comparisons between perforating artery and non-perforating artery cerebral infarction groups. In the perforating vessel disease group, 12 cases (17.4%) of intracranial hemorrhage occurred, with symptomatic cerebral hemorrhage in three cases (4.3%); there were no significant differences between the perforating and non-perforating vessel disease groups (all P > 0.05). In the perforating vessel disease group, the only significant prognostic factor was the National Institutes of Health Stroke Scale score before thrombolysis (Exp(B) = 1.365; 95% confidence interval [CI] 1.124–1.659; P = 0.002), and the only significant risk factor for hemorrhagic transformation was previous perforator disease (Exp(B) = 0.078; P = 0.038). Regardless of whether an acute infarction is perforating or non-perforating, intravenous thrombolytic therapy can yield a favorable outcome. Therefore, intravenous thrombolysis should be actively administered to treat perforating artery infarctions with a high risk of disability. [ABSTRACT FROM AUTHOR]

Human astrovirus (HAstV) is one of the common causes of acute gastroenteritis in children. The investigation of molecular epidemiology of HAstV is essential for monitoring the emergence and/or re-emergence of new HAstV genotypes, as well as understanding the evolution of HAstV circulating in children suffering from acute gastroenteritis. The present study aimed to investigate the prevalence and distribution of HAstVs strains circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand during 2017–2020. A total of 1500 fecal specimens collected from children with acute gastroenteritis were screened for HAstV by RT-PCR that targeted the partial RdRp in ORF1b and strains were characterized by sequencing and phylogenetic analysis. Of the 1500 fecal samples, 39 (2.6%) were positive for HAstV. Of these, both classic and novel HAstV genotypes, including classic HAstV1–HAstV5, novel HAstV-MLB1, MLB2, and HAstV-VA2, were detected. The data in this study revealed a high divergence of HAstV genotypes circulating in pediatric patients admitted to the hospitals with acute gastroenteritis in Chiang Mai, Thailand during 2017–2020. [ABSTRACT FROM AUTHOR]

Penetrating planetary regolith is extremely important to explore the secrets inside extraterrestrial celestial bodies. Applying the concept and method of bionics to endow planetary regolith-burrowing robots (PRBRs) with elegant and flexible mobility as natural creatures is gradually becoming a research hotspot in the field of planetary robotics. Compared with traditional penetrating methods, such as drilling and excavation, bioinspired burrowing methods are still seldom studied. This work presents a detailed review of the progress and perspective of bioinspired PRBRs. According to the burrowing mechanisms and strategies of creatures, the current bioinspired PRBRs are divided into seven categories, namely wriggling, undulating, dual-anchoring, grabbing-pushing, reciprocating, granular fluidizing methods inspired by animals, and root growth method inspired by plants. The general characteristics of these robots are summarized in-depth, and the advantages and disadvantages are compared. Then, the key technologies of determining the functionalities and performance of bioinspired PRBRs are comprehensively analyzed, including bioinspired mechanism design, motion control, robot-regolith interaction, and terrestrial validation. Finally, the development trend of bioinspired PRBRs is presented, including new mechanisms and materials, autonomous burrowing control, and intelligent perception and communication. [ABSTRACT FROM AUTHOR]

Hollow TiO2 microspheres and carbon/TiO2 (HC/T) composite microspheres have been synthesized by a one-pot synthesis approach. The complex permittivity result shows that the hollow TiO2/paraffin composites have weak polarized loss, and the permittivities of the hollow HC/T/paraffin composites can be easily tuned by the carbonization temperature. The result of reflection loss (RL) exhibits that the microwave absorption performances of HC/T composite are more excellent than hollow TiO2. The hollow HC/T composite carbonized at 800°C shows the most excellent microwave absorption performances because of suitable complex permittivity and impedance matching. [ABSTRACT FROM AUTHOR]

As a research hotspot in the field of robotics, Simultaneous localization and mapping (SLAM) has made great progress in recent years, but few SLAM algorithms take dynamic or movable targets in the scene into account. In this paper, a robust new RGB-D SLAM method with dynamic area detection towards dynamic environments named GMSK-SLAM is proposed. Most of the existing related papers use the method of directly eliminating the whole dynamic targets. Although rejecting dynamic objects can increase the accuracy of robot positioning to a certain extent, this type of algorithm will result in the reduction of the number of available feature points in the image. The lack of sufficient feature points will seriously affect the subsequent precision of positioning and mapping for feature-based SLAM. The proposed GMSK-SLAM method innovatively combines Grid-based Motion Statistics (GMS) feature points matching method with K-means cluster algorithm to distinguish dynamic areas from the images and retain static information from dynamic environments, which can effectively increase the number of reliable feature points and keep more environment features. This method can achieve a highly improvements on localization accuracy in dynamic environments. Finally, sufficient experiments were conducted on the public TUM RGB-D dataset. Compared with ORB-SLAM2 and the RGB-D SLAM, our system, respectively, got 97.3% and 90.2% improvements in dynamic environments localization evaluated by root-mean-square error. The empirical results show that the proposed algorithm can eliminate the influence of the dynamic objects effectively and achieve a comparable or better performance than state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Single-point incremental forming (SPIF) of polymers was started back in the first decade of twenty-first century; since then, substantial studies have been performed on this topic. The present article reviews these studies and compiles the developments in a comprehensive manner. The review entails a number of forming aspects of polymers, the more important of which are deformation mechanics, failure modes, formability, forming forces, springback, and post-forming material characteristics. The agreements and disagreements amongst the researchers are recognized and critical remarks are provided. The issues are identified, and areas of future work are proposed to further comprehend knowledge on the subject in order to successfully deploy the process on industrial scale. The differences in the characteristics of SPIF of polymers and SPIF of metals are also outlined and discussed in this article. The review concludes that the operating parameters and material are the key factors that affect the process performance. Further, the innovative technology must be adopted, and a larger database should be established to enhance industrial viability of the process. [ABSTRACT FROM AUTHOR]

Purpose: To compare transoral and endoscopic transnasal anterior release without odontoidectomy and posterior reduction and fixation to treat irreducible atlantoaxial dislocation (IAAD). Methods: From June 2006 to January 2017, 35 consecutive patients with IAAD underwent transoral (Tr-Oral group) or endoscopic transnasal (Tr-Nasal group) release and posterior fixation and fusion in our department. Clinical neurological recovery (Japanese Orthopedic Association (JOA) score) and radiological reduction parameters including atlantodontoid interval (ADI), space available for the cord (SAC) and cervicomedullary angle (CMA) were analyzed and compared. The operation duration, blood loss, length of intensive care unit (ICU)/hospital stay and complications were recorded. Results: All 35 patients (18 and 17 patients in the Tr-Oral and Tr-Nasal groups, respectively) were followed up for a mean of 36.4 months (range, 21–60 months). All patients achieved excellent anatomical reduction and clinical neurological recovery, with no significant differences between the two groups. The JOA score, ADI, SAC and CMA were not significantly different between the two groups at various postoperative points. Although the Tr-Oral group had shorter operation time and less blood loss than the Tr-Nasal group, the Tr-Nasal group tended to have a significantly shorter hospital/ICU stay, earlier extubation and earlier oral intake than the Tr-Oral group. Conclusion: The transoral and endoscopic transnasal approaches can achieve equivalent release and reduction effects when treating IAAD. Compared to the transoral approach, the endoscopic transnasal route is less invasive with earlier extubation and oral intake, shorter hospital/ICU stays and lower medical costs, which is conducive to enhanced recovery after surgery. [ABSTRACT FROM AUTHOR]

Incremental sheet forming (ISF) is an emerging cold forming process with a high economic payoff. In this study, the influence of the ISF process on the tensile properties of Cu-clad Steel sheet is analyzed experimentally. Depending on the forming conditions, the post-ISF values of yield strength, tensile strength, and ductility are found to range from 161 to 430, 288 to 449 MPa, and 4.93 to 16.62 pct, respectively. These properties show a strong dependence on several correlated quantities such as the applied plastic strain, grain size, and mean residual stress. As the plastic strain increases from 0.08 to 0.8, the width of the grain decreases from 8.11 to 5.78 µm and the residual stress increases from − 15 to − 131 MPa. In comparison to the unformed sheet, ISF enhances the yield strength (4.6 to 117 pct) and tensile strength (0.6 to 73 pct). The nature of change in ductility (− 67 to 117 pct), however, depends on the process conditions, especially the state of the unformed sheet (i.e., rolled/annealed) and the value of applied strain. In general, the rolled (or prestrained) sheet upon ISF experiences an increase in ductility. The annealed sheet, however, sees a drop in ductility when the forming strains are low (e.g., < 0.4) and an increase in ductility when the strains are high (e.g., > 0.4). X-ray diffraction (XRD) and electron dispersive spectroscopy (EDS) analyses confirm that no new phase formed during ISF. [ABSTRACT FROM AUTHOR]

Surface roughness affects the performance and service life of the formed components. To this end, efforts have been spent in the innovative incremental sheet forming (ISF) process. However, the researchers yet have not reached any agreement regarding the process effects on roughness. This demands further research to comprehend the knowledge in order to acquire a threshold level of understanding on surface roughening in the process. The present study investigates the processing effects upon the roughness of interior surfaces and on the friction indicator at the tool/sheet interface during forming of an aluminum sheet. Some of the sparsely studied parameters, namely flow stress, sheet thickness, and forming angle, are undertaken besides commonly considered ones (i.e., tool diameter and step size). The analysis of the results reveals that the friction indicator and roughness are analogous in respect of their response to parameter variations. Further, the roughness in general linearly increases with an increase in the friction indicator because the sheet abrasion correspondingly increases as revealed by the SEM-based surface morphology. A combination of parameters, among several attempted ones, namely dsinθ/2pt (where d is the tool diameter, θ is the forming angle, p is the step size, and t is the sheet thickness), is identified to have controlling influence on the roughness of interior surfaces. This combination is validated employing two materials namely Al1060 and Cu/Steel composite. In this combination, the factor d/2p followed by 1/t is found to have the greatest contribution towards the roughening of surfaces. Moreover, the value of this combination is proposed to keep low in order to produce components with good finish, say ≤ 50 mm−1 for Al10160 and 20 mm−1 for Cu/Steel composite. The present and past roughness studies in ISF are also compared, which reveals that the parameters effects are associated to the type of material. [ABSTRACT FROM AUTHOR]

Introduction: To investigate the short- and medium-term efficacy of inter-spinal distraction fusion (ISDF) for lumbar disc herniation with a spinal internal fixation device, the BacFuse Spinous Process Fusion Plate.Methods: Ninety-five patients who received ISDF between January 2014 and January 2015 were included for the current retrospective study. The symptoms and imaging results before surgery, immediately after surgery, at six months, and at the last follow-up were assessed using the leg visual analogue scale (VAS), Oswestry disability index (ODI), and 12-item short-form survey (SF-12). The intra-operative intervertebral angle (IA), anterior disk height (ADH), posterior disk height (PDH), foramina height (FH), foramina width (FW), and range of motion (ROM) were assessed using X-rays. The foramina and herniated disc area were assessed using computed tomography (CT).Results: The leg VAS, ODI, and SF-12 were significantly improved after surgery. All indices except ADH were also significantly improved after surgery. PDH and FH increased by 15.5% (P < 0.001) and 9.7% (P < 0.001) at the last follow-up. ROM was statistically different from before surgery. CT images indicated that the herniated disc area decreased by 3.1%, while the foramina areas increased by 5.7% at the last follow-up. 92.6% patients demonstrated successful outcome.Conclusions: ISDF significantly alleviated the clinical symptoms, improved spinal structure, and partially retracted the herniated disc. Our findings imply that ISDF is an effective minimally invasive procedure in the treatment of lumbar disc herniation. [ABSTRACT FROM AUTHOR]

A new constrained flow mode was developed to improve the machining stability in pulse electrochemical machining (PECM) of micro channel arrays on metallic bipolar plate. In electrochemical machining (ECM), the electrolyte flow field in the machining region is a key factor influencing processing stability and surface quality. In this study, a multifunctional cathode (MFC) was designed in the process, which was prepared with casting molding method. MFC acted as electrode, as well as sealing device and isolating individual machining regions. The channels of electrode were filled with elastic blocks, which were tightly pressed against the surface of workpiece during process to separate the large machining region into multiple independent machining regions. Therefore, the machining area would have sufficient electrolyte, and the flow field of each channel was independent from each other. 3-D flow field simulation was developed in this study to analyze the flow field of the channel arrays. It indicated that multiple independent machining regions could effectively improve the velocity uniformity of each channel. The experiments revealed that the uniformity of flow field had a positive role to prevent from spark discharge and short circuit, as well as the machining efficiency and machining stability. The channel arrays with 466-μm depth were machined on SS304 metallic BP within 2 min. [ABSTRACT FROM AUTHOR]

To solve the problems of poor forming and easy adhesion of the stainless steel, Cu alloyed layer on the stainless steels was prepared by the double glow plasma surface alloying technique. The experimental results indicated that the supersaturated copper dispersedly precipitated in grain interior and crystal boundaries and formed the vermicular structure. The tribological tests indicated that the friction coefficient of the Cu alloyed layer was lower than that of the stainless steels. The wear rate of stainless steel in the presence of Cu alloyed layer was approximately 2-fold lower than that in the absence of the alloyed layer. The results of the incremental forming indicated that the ploughing phenomenon was not observed on the stainless steel in the presence of Cu alloyed layer during the incremental forming, while the stainless steel presented the deep ploughing. Therefore, Cu alloyed layer on stainless steel exhibited excellent self-lubrication and forming properties. [ABSTRACT FROM AUTHOR]

Diapycnal mixing (DM) in the upper 600 m of the Pacific Ocean was estimated based on the huge amount of the observations from Global Temperature-Salinity Profile Programme (GTSPP), using the strain version of the finescale parameterization. It is found that DM in each season exhibits similar distribution pattern, but differs in details. The intensification of DM is related to bottom roughness, surface near-inertial energy, and proximity to the equator. The intensified DM caused by rough topography shows in the profiles near the Mendocino fracture zone in the northeast Pacific, and the heightened DM caused by wind-generated near-inertial energy appears in the westerly region of the Southern Ocean. As compared to previous estimates, the DM estimate in this work has better spatial coverage and finer resolution, and more importantly it contains the seasonal variability. Furthermore, the resulting DM dataset is gridded, rendering it suitable for modeling applications. [ABSTRACT FROM AUTHOR]

Author Correction: High divergence of human astrovirus genotypes circulating in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand, 2017-2020 Correction to: I Scientific Reports i https://doi.org/10.1038/s41598-021-02745-7, published online 01 December 2021 The original version of this Article contained errors in Table 1, where the percentage total (%) of "No. of HAstV co-infection" was incorrect. [Extracted from the article]

Single point incremental forming (SPIF) is an innovative sheet forming process with a high economic pay-off. The formability in this process can be maximized by executing forming with a tool of specific small radius, regarded as threshold critical radius. Its value has been reported as 2.2 mm for 1 mm thick sheet materials. However, with a change in the forming conditions specifically in the sheet thickness and step size, the critical radius is likely to alter due to a change in the bending condition. The main aim of the present study is to undertake this point into account and develop a relatively generic condition. The study is composed of experimental and numerical investigations. The maximum wall angle (θmax) without sheet fracturing is regarded as sheet formability. A number of sheet materials are formed to fracture and the trends correlating formability with normalized radius (i.e., R/To where R is the tool-radius and To is the sheet thickness) are drawn. These trends confirm that there is a critical tool-radius (Rc) that maximizes the formability in SPIF. Furthermore, it is found that the critical radius is not fixed rather it shows dependence on the sheet thickness such that Rc = βTo, where β varies from 2.2 to 3.3 as the thickness increases from 1 mm to 3 mm. The critical radius, however, remains insensitive to variation in step size ranging from 0.3 mm to 0.7 mm. This is also observed that the selection of tool with R < Rc narrows down the formability window not only on the higher side but also on the lower side. The higher limit, as revealed by the experimental and FEA results, diminishes due to excessive shearing because of in-plane biaxial compression, and the lower limit reduces due to pillowing in the bottom of part. The new tool-radius condition proposed herein study would be helpful in maximizing the formability of materials in SPIF without performing experimental trials. [ABSTRACT FROM AUTHOR]