Size, shape and orientation of macro-sized substrate protrusions affect the toe and foot adhesion of geckos

Geckos are excellent climbers using compliant, hierarchically arranged adhesive toes to negotiate diverse terrains varying in roughness at multiple size scales. Here, we complement advancements at smaller size scales with measurements at the macro scale. We studied the attachment of a single toe and whole foot of geckos on macroscale rough substrates by pulling them along, across and off smooth rods and spheres mimicking different geometric protrusions of substrates. When we pulled a single toe along rods, the force increased with the rod diameter, whereas the attachment force of dragging toes across rods increased from about 60% on small diameter rods relative to a flat surface to ∼100% on larger diameter rods, but showed no further increase as rod diameter doubled. Toe force also increased as the pulling changed from along-rod loading to across-rod loading. When toes were pulled off spheres, the force increased with increasing sphere diameter as observed for along-rod pulling. For feet with separated toes, attachment on spheres was stronger than that on rods with the same diameter. Attachment force of a foot decreased as rod and sphere size increased but remained sufficient to support the body weight of geckos. These results provide a bridge to the macroscale roughness seen in nature by revealing the importance of the dimension, shape and orientation of macroscale substrate features for compliant toe and foot function of geckos. Our data not only enhance our understanding of geckos' environmental adaptive adhesion but can also provide inspiration for novel robot feet in development.

A Comparative Study of Adaptive Interlimb Coordination Mechanisms for Self-Organized Robot Locomotion

Walking animals demonstrate impressive self-organized locomotion and adaptation to body property changes by skillfully manipulating their complicated and redundant musculoskeletal systems. Adaptive interlimb coordination plays a crucial role in this achievement. It has been identified that interlimb coordination is generated through dynamical interactions between the neural system, musculoskeletal system, and environment. Based on this principle, two classical interlimb coordination mechanisms (continuous phase modulation and phase resetting) have been proposed independently. These mechanisms use decoupled central pattern generators (CPGs) with sensory feedback, such as ground reaction forces (GRFs), to generate robot locomotion autonomously without predefining it (i.e., self-organized locomotion). A comparative study was conducted on the two mechanisms under decoupled CPG-based control implemented on a quadruped robot in simulation. Their characteristics were compared by observing their CPG phase convergence processes at different control parameter values. Additionally, the mechanisms were investigated when the robot faced various unexpected situations, such as noisy feedback, leg motor damage, and carrying a load. The comparative study reveals that the phase modulation and resetting mechanisms demonstrate satisfactory performance when they are subjected to symmetric and asymmetric GRF distributions, respectively. This work also suggests a strategy for the appropriate selection of adaptive interlimb coordination mechanisms under different conditions and for the optimal setting of their control parameter values to enhance their control performance.

Metabolomic evaluation of serum metabolites of geese reared at different stocking densities

1. Stocking density is an issue for poultry production. High stocking density can impact biochemical parameters, production, and reproductive performance; however, information regarding the effects of stocking density on serum metabolites in geese is limited.2. Twenty-day-old, Sanhua male geese (n = 240) were allocated to one of two experimental groups for 50 days. One group was housed under a low stocking density (LSD; two birds per m²) and one under a high stocking density (HSD; five birds per m²). Body weight and feed intake were recorded every 10 d. Eight serum samples per group were used for metabonomic analysis by liquid chromatography-mass spectrometry.3. Stocking density did not affect the spleen, liver, thymus, or bursa of Fabricius weights after 50 d. Feed intake and body weight was significantly lower in geese from the HSD group versus the LSD group (P < 0.05). Thirty-six differential serum metabolites were identified (P < 0.05), indicating altered amino acid, carbohydrate, lipid and vitamin cofactor metabolism.4. The results demonstrated that high-density stocking impacts geese, and provides insights into the mechanisms underlying the adverse health effects associated with HSD.

Angular variables of climbing geckos in two lateral undulation patterns

Geckos demonstrate flexible and agile locomotion on diverse terrains and surfaces. The lateral undulation pattern referring to the trunk-limbs coordination gives animals advantages in terms of motion speed, dynamical stability, and highly efficient movement. Quantitative analysis of the angular variables of the trunk and limbs was proposed to compare the kinematics of Gekko gecko on the vertical plane in the standing wave and traveling wave of lateral undulation patterns. Thirteen angular variables were measured to illustrate the kinematic characteristics of trunk flexion, girdles rotation, scapula rotation, trunk deflection, femoral/humeral protraction-retraction, abduction-adduction, and rotation around their axes, and knee/elbow flexion-extension. One-way analysis of variance (ANOVA) tested for mean differences between patterns for maximum value, minimum value, and range value of each angular variable. The geckos adapted to the changes in locomotion velocity by dynamically adjusting the joints angular variables. Twenty of the thirty-nine angular values showed a significant pattern effect that presented the variation of angular values or the timing of the peak of the angle curve in two different lateral undulation patterns. The climbing stability of a gecko is tightly associated with the coordination between the body and the limbs.

Percutaneous transluminal septal myocardial ablation markedly reduces energy loss in hypertrophic obstructive cardiomyopathy: a four-dimensional flow magnetic resonance imaging study

Background

Functional follow-up modalities of hypertrophic obstructive cardiomyopathy (HOCM) subjected to percutaneous transluminal septal myocardial ablation (PTSMA) are limited mainly to echocardiography and catheterization. Recent advancements in four-dimensional (4D) flow magnetic resonance imaging (MRI) have enabled us to assess patients from the perspective of fluid dynamics by visualising blood flow and calculating quantitative parameters such as wall shear stress and energy loss within cardiac chambers or blood vessels. Several reports have demonstrated that the intra-cardiac energy loss decreased along with improvement of cardiac function achieved by treatment of cardiac diseases. Whether changes in energy loss occur along with PTSMA in HOCM patients and the underlying mechanism remain unknown.

Purpose

This study sought to investigate the influence of PTSMA in patients with HOCM on energy loss in the left ventricle (LV) and aortic root measured by 4D flow MRI.

Methods

We retrospectively recruited HOCM patients who underwent PTSMA at a referral centre from May to November 2019. Patients who underwent 4D flow MRI both before and after PTSMA were included. We collected demographic and clinical data from electronic health records. MRI scans implemented two-dimensional phase-contrast imaging of the three-chamber plane with three-directional velocity, using a 1.5 T scanner. Furthermore, 4D blood flow analysis was performed on off-line saved data, using iTFlow version 1.9. We assessed energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root (area surrounded by the LV endocardium, sinotubular junction, and mitral annulus).

Results

This study finally included 12 patients, whose mean age was 66±12 years, and 5 (42%) of whom were men. The pressure gradient between the LV apex and ascending aorta was 81±32 mmHg before and 20±22 mmHg immediately after PTSMA (P&lt;0.005, paired). Before PTSMA, 6 patients were in New York Heart Association functional class III and the other 6 in class II. However, after PTSMA, 10 patients improved to class I and 2 to class II. PTSMA reduced energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root, from 79±36 mJ/m to 55±19 mJ/m (P=0.001, paired).

Conclusions

PTSMA in patients with HOCM reduced energy loss within the LV and aortic root, indicating significant decrease with cardiac workload. Four-dimensional flow MRI of the three-chamber plane to assess energy loss within the LV and aortic root is a time-efficient and reproducible quantitative method to evaluate the effects of PTSMA. Given its non-invasive nature, it also enables to sequentially follow-up HOCM patients who underwent PTSMA.

Periprocedural changes of energy loss

Funding Acknowledgement

Type of funding source: None

Influence of carbon dioxide plasma treatment on the dry adhesion of vertical aligned carbon nanotube arrays

Vertical aligned carbon nanotube (VACNT) arrays used as dry adhesive materials have broad prospects in the applied fields of space, medicine and electronics. The adhesion of VACNT arrays is believed to be related not only to the nano-array structure and a clean surface, but also to chemical composition. Here, radio-frequency (RF) carbon dioxide (CO₂) plasma treatment is introduced as an effective method for purifying and functionalizing the surface to improve the dry adhesive performance of VACNT arrays. Scanning electron microscopy showed that the VACNT arrays retained the alignment architecture with minimal damage at low power. X-ray photoelectron spectroscopy and contact angle tests revealed that the content of non-polar components (C = C bonds) decreased after treatment, while the content of polar groups (C = O and O-C = O bonds) increased, which changed the surface polarity of the VACNT arrays. Raman analyses and transmission electron microscopy demonstrated that amorphous carbon can be selectively removed with increasing time (0-18 min), but was continuously generated with increasing power (30-90 W). The best adhesive strength of 18 N cm^-2 (increased by 39%) was obtained after CO₂ plasma treating for 10 min at 30 W power, which was attributed to the combined action of purification and polarization.

Role of multiple, adjustable toes in distributed control shown by sideways wall-running in geckos

Remarkable progress has been made characterizing one of nature's most integrated, hierarchical structures--the fibrillar adhesive system of geckos. Nonetheless, we lack an understanding of how multiple toes coordinate to facilitate geckos' acrobatic locomotion. Here, we tested the control function of gecko toes by running them on vertical substrates varying in orientation, friction and roughness. Sideways wall-running geckos realigned the toes of their top feet upward to resist gravity. Toe contact area was not compromised, but redistributed. Geckos aligned all toes upward to resist slipping when encountering low-friction patches during sideways wall-running. Negotiation of intermittent slippery strips showed an increased contribution of particular toes to compensate for toes that lost adhesion. Increasing substrate roughness using discrete rods perpendicular to sideways locomotion resulted in geckos bending and/or rotating toes to conform to and even grasp the rods, with potential forces more than five times body weight. Geckos increase their effectiveness of manoeuvrability in demanding environments by taking advantage of the distributed control afforded by multiple toes. Our findings provide insight on biological attachment and offer inspiration to advance gecko-inspired robotics and other biomimetic applications.

Small-Sized Reconfigurable Quadruped Robot With Multiple Sensory Feedback for Studying Adaptive and Versatile Behaviors

Self-organization of locomotion characterizes the feature of automatically spontaneous gait generation without preprogrammed limb movement coordination. To study this feature in quadruped locomotion, we propose here a new open-source, small-sized reconfigurable quadruped robot, called Lilibot, with multiple sensory feedback and its physical simulation. Lilibot was designed as a friendly quadrupedal platform with unique characteristics, including light weight, easy handling, modular components, and multiple real-time sensory feedback. Its modular components can be flexibly reconfigured to obtain features, such as different leg orientations for testing the effectiveness and generalization of self-organized locomotion control. Its multiple sensory feedback (i.e., joint angles, joint velocities, joint currents, joint voltages, and body inclination) can support vestibular reflexes and compliant control mechanisms for body posture stabilization and compliant behavior, respectively. To evaluate the performance of Lilibot, we implemented our developed adaptive neural controller on it. The experimental results demonstrated that Lilibot can autonomously and rapidly exhibit adaptive and versatile behaviors, including spontaneous self-organized locomotion (i.e., adaptive locomotion) under different leg orientations, body posture stabilization on a tiltable plane, and leg compliance for unexpected external load compensation. To this end, we successfully developed an open-source, friendly, small-sized, and lightweight quadruped robot with reconfigurable legs and multiple sensory feedback that can serve as a generic quadrupedal platform for research and education in the fields of locomotion, vestibular reflex-based, and compliant control.

Overexpression of miR-146a inhibits the apoptosis of hippocampal neurons of rats with cerebral hemorrhage by regulating autophagy

In this study, to investigate the effect of overexpression of miR-146a on autophagy of hippocampal neurons in rats with intracerebral hemorrhage (ICH), 72 Sprague-Dawley rats were randomly divided into the sham, ICH, miR-146a agomir, and miR-146a agomir control groups. The ICH model was constructed by injection of collagenase VII. The apoptosis of hippocampal neurons was measured by TUNEL assay. The levels of LC3 and Beclin 1 were analyzed by immunohistochemistry. Mitochondrial autophagy was examined by transmission electron microscopy. The levels of LC3A, LC3B, Beclin 1, Bax, Bcl-2, and cleaved caspase 3 were examined by Western blot. Western blot was also used to evaluate the expression of nuclear factor κB signaling pathway-related factors. To examine the effect of autophagy inhibitor (3-methyladenine (3-MA)) on miR-146a-regulated apoptotic protein expression, 30 rats were further divided into the sham, ICH, miR-146a agomir, 3-MA, and miR-146a + 3-MA groups. The levels of Bax, Bcl-2, and cleaved caspase 3 were examined by Western blot. Compared with the sham group, the nerve function scores, brain water content, the percentage of apoptotic cells, and the expression levels of LC3, Beclin 1, Bax, cleaved caspase 3, and p-P65 in the hippocampus of rats in the ICH group were all significantly increased (p < 0.05), whereas the expression levels of miR-146a, Bcl-2, and p-IκBα were markedly decreased (p < 0.05). Mitochondrial autophagy was also evident. Furthermore, compared with the ICH group, the results of the abovementioned tests in the miR-146a agomir group were reversed. The overexpression of miR-146a inhibited the autophagy of hippocampal neurons in rats with ICH.

[Reflections on the orientation of public health physicians]

Public health physician is one of the four statutory types of physicians in China, but there is no consensus on their connotation. The main problems are that public health physician is confused with those who perform public health tasks, the relationship between public health physician and clinician and the connotation of prescription right is not clear, and there is limitation in public health education and relevant laws and regulations. Public health physician is positioned as professionals who monitor, investigate, evaluate, and intervene in population health-related issues. It is suggested to retain the practicing qualification of public health physicians and highlight the attribute of public health physicians' prescribing the prescriptions for community health. Encourage public health physicians to obtain qualification for clinicians to individual prescription, Encourage clinicians to access to public health physician qualification. Improve public health school education, take the pilot of public health physician standardization training, cultivate "prevention and treatment combined" physician.

P1643An exploratory analysis for the optimal monitoring interval of N-terminal pro-B-type natriuretic peptide in patients with stable heart failure

Background

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a potential biomarker for monitoring the status of heart failure. However, the optimal monitoring interval is unknown. This study aims to investigate minimal informative monitoring interval of NT-proBNP in patients with stable chronic heart failure.

Methods

In this retrospective open cohort study, adult patients followed up at a tertiary hospital for chronic heart failure with NT-proBNP measurements were included if they had been previously admitted due to acute heart failure and were free from readmission over 6 months after discharge. We analyzed NT-proBNP measured between 6 months after discharge and the timepoint of an alteration of medication regimen or readmission due to worsening of heart failure. To distinguish actual progression of the disease from biological variability and measurement error, the signal-to-noise ratio method was applied with a random-effects model. Stratified analysis was performed according to underlying risks.

Results

In this analysis, 368 patients were included with NT-proBNP measured between July 2009 and December 2017. The patients had 6.0 times of NT-proBNP measurements in median (interquartile range [IQR] 4.0–10.0) during the follow-up period (median 12.0 months [IQR 6.0–27.0]). In the estimates of the random-effects model, signal (i.e. actual progression of the disease) exceeded noise (i.e. biological variability and measurement error) at 8.1 months (95% confidence interval [CI]: 5.7–10.1) after the index measurement. In a subgroup analysis according to the AHEAD risk score, the minimal informative monitoring interval was shortened as the risk score increased (0–1 point: 12.3 months [95% CI: 10.3–14.5]; 2–3 points: 8.0 months [95% CI: 6.8–9.7]; 4–5 points: 3.3 months [95% CI: 3.0–3.8]; Figure).

Informative intervals stratified by risk

Conclusion

In patients with stable chronic heart failure, the overall minimal informative monitoring interval of NT-proBNP measurement was 8.1 months, which varies by underlying risk. The optimal monitoring interval could be lengthened especially for patients at lower risk.

Identification of key pathways and genes changes in pancreatic cancer cells (BXPC-3) after cross-talk with primary pancreatic stellate cells using bioinformatics analysis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with poor prognosis, and the interaction between activated pancreatic stellate cells (PSCs) and PDAC cells plays an important role in the development of PDAC. The aim of this study was to identify gene changes in BXPC-3 after cross-talk with PSCs and reveal their potential mechanisms. The gene expression profiling analysis of BXPC-3 was completed after co-culture with primary PSCs for 48 h. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed, and the differentially expressed genes (DEGs) were identified by Agilent GeneSpring GX software. In total, 3657 DEGs were identified in BXPC-3, including 1881 up-regulated genes and 1776 downregulated genes. GO analysis results showed that upregulated DEGs were significantly enriched in biological processes (BP), including peptide metabolic process, response to stress and electron transport chain; the downregulated DEGs were significantly enriched in biological processes, including signaling, multicellular organism development and anatomical structure development. KEGG pathway analysis revealed that 19 pathways were upregulated and 32 pathways were downregulated, and that upregulated DEGs were enriched in protein export and glutathione metabolism, while the downregulated DEGs were enriched in axon guidance and focal adhesion. The top 10 upregulated genes and the top 10 downregulated genes were identified. By constructing PPI network, we selected out 10 key genes (TP53, SRC, IL6, JUN, ISG15, CAD, STAT1, OAS3, OAS1, VIM) and significant pathways. The associated survival analysis was performed and the SRC, IL-6, ISG15, STAT1, OAS3, OAS1 and VIM were proved to be related to worse overall survival time of PDAC patients. In conclusion, the present study indicated that the identified DEGs promote our understanding of the molecular mechanisms underlying the interaction between pancreatic cancer cells and PSCs and might be used as molecular targets in the future to study the role of tumor microenvironment in the progression of PDAC.

Kaempferol attenuates imiquimod-induced psoriatic skin inflammation in a mouse model

Psoriasis is an immune-mediated inflammatory skin disease that mainly affects the skin barrier. Treatment for psoriasis mainly includes conventional immunosuppressive drugs. However, long-term treatment with global immunosuppressive agents may cause a variety of side effects, including nephrotoxicity and infections. Kaempferol, a natural flavonol present in various plants, is known to possess potent anti-inflammatory, anti-oxidant and anti-cancerous properties. However, it is unknown whether kaempferol is also anti-psoriatic. Here we established an imiquimod (IMQ)-induced psoriatic mouse model to explore the potential therapeutic effects of kaempferol on psoriatic skin lesions and inflammation. In this study, we demonstrated that treatment with kaempferol protected mice from developing psoriasis-like skin lesions induced by topical administration of IMQ. Kaempferol reduced CD3⁺ T cell infiltration and gene expression of major proinflammatory cytokines, including interleukin (IL)-6, IL-17A and tumor necrosis factor (TNF)-α, in the psoriatic skin lesion. It also down-regulated proinflammatory nuclear factor kappa B (NF-κB) signaling in the skin. The therapeutic effects were associated with a significant increase in CD4⁺ forkhead box protein 3 (FoxP3)⁺ regulatory T cell (T_reg ) frequency in the spleen and lymph nodes as well as FoxP3-positive staining in the skin lesion. Conversely, depletion of CD4⁺ CD25⁺ T_regs reversed the therapeutic effects of kaempferol on the skin lesion. Kaempferol also lowered the percentage of IL-17A⁺ CD4⁺ T cells in the spleen and lymph nodes of IMQ-induced psoriatic mice. Finally, kaempferol suppressed the proliferation of T cells in vitro and their mTOR signaling. Thus, our findings suggest that kaempferol may be a therapeutic drug for treating human psoriasis in the near future.

[A survey of attitudes to and demands on internship in graduates majoring in preventive medicine in 6 colleges and universities in China]

Objective: To understand the internship of students majoring in preventive medicine in 6 colleges and universities in China, and provide reference suggestions for the improvement of internship arrangement. Methods: By using the method of combined clustering and convenient sampling, the fifth grades students majoring in preventive medicine in six universities in the eastern, central and western China were surveyed by using questionnaires to collect the information of their attitudes (to) and suggestions for clinical and public health internships. Results: A total of 596 students were surveyed. In terms of the benefits of clinical internship and public health internship, students who thought that the internship was fruitful accounted for >88%, and more students thought that reform is needed in clinical internship compared with public health internship. In clinical internship, the students through that the time arrangement was not appropriate enough (95, 39.58%), the content should be more detailed and in-depth (73, 30.42%) and the content did not conform to the professional direction (54, 22.50%). In public health internship, the students thought that the time arrangement was not appropriate (77, 45.56%), the content should be more detailed and standardized (65, 38.46%) and the types of internship bases should be more diversified (20, 11.83%). Conclusions: The undergraduates majoring in preventive medicine felt to be benefited from clinical practice and public health internships and thought they are of necessity. At the same time, there are still many problems which needs to be improved in the two types of internships. It is necessary to make joint efforts from students, teachers, colleges and practice bases to promote the continuous improvement of undergraduate internship.

Identification of key pathways and genes changes in pancreatic cancer cells (BXPC-3) after cross-talked with primary pancreatic stellate cells using bioinformatics analysis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with poor prognosis, and the interaction between activated pancreatic stellate cells (PSCs) and PDAC cells plays an important role in the development of PDAC. The aim of this study was to identify gene changes in BXPC-3 after cross-talked with PSCs and reveal their potential mechanisms. The gene expression profiling analysis of BXPC-3 was completed after co-cultured with primary PSCs for 48 h. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed, and the differentially expressed genes (DEGs) were identified by Agilent GeneSpring GX software. In total, 3657 DEGs were identified in BXPC-3, including 1881 up-regulated genes and 1776 downregulated genes. GO analysis results showed that up-regulated DEGs were significantly enriched in biological processes (BP), including peptide metabolic process, response to stress, and electron transport chain; the down-regulated DEGs were significantly enriched in biological processes, including signaling, multicellular organismal development, and anatomical structure development. KEGG pathway analysis revealed that 19 pathways were upregulated and 32 pathways were downregulated, and that up-regulated DEGs were enriched in protein export and glutathione metabolism, while the down-regulated DEGs were enriched in axon guidance and focal adhesion. The top 10 up-regulated genes, and the top 10 down-regulated genes were identified. By constructing PPI network, we selected out 10 key genes (TP53, SRC, IL6, JUN, ISG15, CAD, STAT1, OAS3, OAS1, VIM) and significant pathways. The associated survival analysis was performed and the SRC, IL-6, ISG15, STAT1, OAS3, OAS1 and VIM were proved to be related to worse overall survival time of PDAC patients. In conclusion, the present study indicated that the identified DEGs promote our understanding of the molecular mechanisms underlying the interaction between pancreatic cancer cells and PSCs and might be used as molecular targets in the future to study the role of tumor microenvironment in the progression of PDAC.