Research on a Precision Calibration Model of a Flexible Strain Sensor Based on a Variable Section Cantilever Beam.

The flexible strain sensor's measuring range is usually over 5000 µÎµ, while the conventional variable section cantilever calibration model has a measuring range within 1000 µÎµ. In order to satisfy the calibration requirements of flexible strain sensors, a new measurement model was proposed to solve the inaccurate calculation problem of the theoretical strain value when the linear model of a variable section cantilever beam was applied to a large range. The nonlinear relationship between deflection and strain was established. The finite element analysis of a variable section cantilever beam with ANSYS shows that the linear model's relative deviation is as high as 6% at 5000 µÎµ, while the relative deviation of the nonlinear model is only 0.2%. The relative expansion uncertainty of the flexible resistance strain sensor is 0.365% (k = 2). Simulation and experimental results show that this method solves the imprecision of the theoretical model effectively and realizes the accurate calibration of a large range of strain sensors. The research results enrich the measurement models and calibration models for flexible strain sensors and contribute to the development of strain metering.

Transcriptome analysis reveals the molecular mechanisms of adaptation to high temperatures in Gracilaria bailinae.

Global warming causes great thermal stress to macroalgae and those species that can adapt to it are thought to be better able to cope with warmer oceans. Gracilaria bailinae, a macroalgae with high economic and ecological values, can survive through the hot summer in the South China Sea, but the molecular mechanisms underlying its adaptation to high temperatures are unclear. To address this issue, the present study analyzed the growth and transcriptome of G. bailinae after a 7-day exposure to 15°C (LT: low temperature), 25°C (MT: middle temperature), and 35°C (HT: high temperature). Growth analysis showed that the HT group had the highest relative growth rate (RGR = 2.1%) with the maximum photochemical quantum yield of PSII (F v/F m = 0.62) remaining within the normal range. Transcriptome analysis showed more differentially expressed genes (DEGs) in the comparison between MT and HT groups than in that between MT and LT, and most of these DEGs tended to be downregulated at higher temperatures. The KEGG pathway enrichment analysis showed that the DEGs were mainly enriched in the carbohydrate, energy, and lipid metabolisms. In addition, the genes involved in NADPH and ATP synthesis, which are associated with photosynthesis, the Calvin cycle, pyruvate metabolism, and the citrate cycle, were downregulated. Downregulation was also observed in genes that encode enzymes involved in fatty acid desaturation and alpha-linolenic acid metabolism. In summary, G. bailinae regulated the synthesis of NADPH and ATP, which are involved in the above-mentioned processes, to reduce unnecessary energy consumption, and limited the synthesis of enzymes in the metabolism of unsaturated fatty acids and alpha-linolenic acid to adapt to high environmental temperatures. The results of this study improve our understanding of the molecular mechanisms underlying the adaptation of G. bailinae to high temperatures.

Calibration Model Optimization for Strain Metrology of Equal Strength Beams Using Deflection Measurements.

Strain sensors, especially fiber Bragg grating (FBG) sensors, are of great importance in structural health monitoring, mechanical property analysis, and so on. Their metrological accuracy is typically evaluated by equal strength beams. The traditional strain calibration model using the equal strength beams was built based on an approximation method by small deformation theory. However, its measurement accuracy would be decreased while the beams are under the large deformation condition or under high temperature environments. For this reason, an optimized strain calibration model is developed for equal strength beams based on the deflection method. By combining the structural parameters of a specific equal strength beam and finite element analysis method, a correction coefficient is introduced into the traditional model, and an accurate application-oriented optimization formula is obtained for specific projects. The determination method of optimal deflection measurement position is also presented to further improve the strain calibration accuracy by error analysis of the deflection measurement system. Strain calibration experiments of the equal strength beam were carried out, and the error introduced by the calibration device can be reduced from 10 µÎµ to less than 1 µÎµ. Experimental results show that the optimized strain calibration model and the optimum deflection measurement position can be employed successfully under large deformation conditions, and the deformation measurement accuracy is improved greatly. This study is helpful to effectively establish metrological traceability for strain sensors and furthermore improve the measurement accuracy of strain sensors in practical engineering scenarious.

Investigation on the Impact of Excitation Amplitude on AFM-TM Microcantilever Beam System's Dynamic Characteristics and Implementation of an Equivalent Circuit.

Alterations in the dynamical properties of an atomic force microscope microcantilever beam system in tapping mode can appreciably impact its measurement precision. Understanding the influence mechanism of dynamic parameter changes on the system's motion characteristics is vital to improve the accuracy of the atomic force microscope in tapping mode (AFM-TM). In this study, we categorize the mathematical model of the AFM-TM microcantilever beam system into systems 1 and 2 based on actual working conditions. Then, we analyze the alterations in the dynamic properties of both systems due to external excitation variations using bifurcation diagrams, phase trajectories, Lyapunov indices, and attraction domains. The numerical simulation results show that when the dimensionless external excitation g < 0.183, the motion state of system 2 is period 1. When g < 0.9, the motion state of system 1 is period 1 motion. Finally, we develop the equivalent circuit model of the AFM-TM microcantilever beam and perform related software simulations, along with practical circuit experiments. Our experimental results indicate that the constructed equivalent circuit can effectively analyze the dynamic characteristics of the AFM-TM microcantilever beam system in the presence of complex external environmental factors. It is observed that the practical circuit simulation attenuates high-frequency signals, resulting in a 31.4% reduction in excitation amplitude compared to numerical simulation results. This provides an essential theoretical foundation for selecting external excitation parameters for AFM-TM cantilever beams and offers a novel method for analyzing the dynamics of micro- and nanomechanical systems, as well as other nonlinear systems.

Mechanism of macroalgae Gracilaria bailiniae responding to cadmium and lanthanum.

Macroalgae can accumulate a wide array of metals, leading to their appliance as biomonitors of aquatic environments. With the rapid development of industrial and agricultural-based activities, Cd pollution in aquatic environments is considered an increasingly severe problem worldwide. Although La could alleviate the Cd stress in higher terrestrial plants, the response mechanisms of macroalgae to Cd and La are unknown. Along these lines, in this work, Cd significantly affected the growth, internal cellular structure, photosynthesis, pigment content, antioxidant enzyme activity, and lipid peroxidation level of G. bailiniae. However, the presence of La alleviated these adverse effects from Cd. Furthermore, the response mechanism of G. bailiniae to Cd was attributed to the self-antioxidant ability enhancement, membrane defense, and programmed-cellular regulation. However, the presence of La mediated the biosynthesis of both flavonoids and lipids, which inhibited the Cd accumulation, modulated algal stress signalling networks, renewed the impaired chlorophyll molecule, maintained the activity of the crucial enzyme, enhanced antioxidant ability, and maintained the stabilization of redox homeostasis, alleviating the adverse impact from Cd and improve the growth of G. bailiniae. The experimental results successfully demonstrate a new detoxicant to alleviate Cd stress, promoting a more comprehensive array of macroalgal applications.

Land-use transition and its driving forces in a minority mountainous area: a case study from Mao County, Sichuan Province, China.

Land-use change is an important research topic in global environmental change. Analyzing land-use change and its driving factors can aid in the evaluation of the current and the determination of future land-use policies. This study took Mao County, Southwest China, as the study area and used the land-use change and statistical data surveyed in 2009 and 2019. With the help of geographic information system technology, a land-use transfer matrix was used to comprehensively analyze the characteristics of spatiotemporal differentiation of land use, while the driving mechanism was analyzed by constructing the influencing factors using a geographical detector model. The results showed that the change in land use in Mao County was drastic. The increasing land types included orchards, grasslands, built-up lands, and water bodies, whereas the decreasing land types included croplands, forestlands, and unused lands. The main driving factors of land-use transition depended on the type of land-use change. Elevation, distance from the county government, and population were the main driving factors of land-use change. Road density, distance from the river, distance from the town/township government, and gross domestic product also affected land-use change to a certain extent, whereas relief and slope had less impact.

Mechanism of the allelopathic effect of macroalgae Gracilaria bailiniae on Nitzschia closterium.

With the rapid development of the seaweed industry in China, the scale and production of its commercial seaweed are ranked among the most significant worldwide. Consequently, the control of algal blooms, especially fouling diatoms, during macroalgae industrialisation is an important issue. Many diatom bloom studies have focused on physical and chemical controls, with limited economic and eco-friendly biological controls reported. In our study, Gracilaria bailiniae fresh thalli and aqueous extract profoundly suppressed Nitzschia closterium growth (50% inhibition concentration of the fourth day (IC50-4 day) was 0.667 × 10-3 g·mL-1 and 3.889 × 10-3 g·mL-1, respectively). The cellular morphology changes of N. closterium exposed to the G. bailiniae aqueous extract were severe atrophies and plasmolysis and dissolution of endocellular structures. To explore more potential allelochemicals to control N. closterium, the intracellular compounds of G. bailiniae were detected and screened. Three organic acids (citrate, hydroxyethanesulfonic acid (HA) and taurine) had allelopathic potential against N. closterium. Our results showed that citrate and HA markedly suppressed N. closterium (IC50-4 day: 1.035 mM and 1.151 mM, respectively); however, taurine poorly suppressed N. closterium (IC50-4 day: 2.500 mM). Therefore, HA is one of the main allelopathic compounds in G. bailiniae. Further, the allelopathic mechanism of HA against the N. closterium photosynthetic system broke its photosynthetic apparatus (oxygen-evolving complex, reaction centres, the effective antenna size and the donor side of photosystem II) and hindered electron transport. The experimental results provide a new and eco-friendly strategy to control diatom blooms.

The complete mitochondrial genome of a Green macroalgae species: Ulva meridionalis (Ulvales: Ulvaceae).

Ulva meridionalis, a green macroalgae, is one of the causal species for green tides in Japan and spread into the coast of China. During this research, we sequenced the complete mitochondrial genome of U. meridionalis. The mitogenome is 62,887 bp in length, including 28 encoding genes and 29 tRNA genes. Compared with the Ulva species from mitogenome, the gene order and organization of this mitogenome are similar to most of other determined Ulva mitogenomes, with the nucleotide base composition of A 33.6%, T 32.2%, C 16.2%, and G 18.0%. Phylogenetic analysis shows U. meridionalis is closely related to Ulva flexuosa.

IPDN-China promotes the development of pediatric dialysis in China.

BACKGROUND: In mainland China, dialysis for children with end-stage renal disease (ESRD) was not introduced until the 1980s. To describe the development of pediatric dialysis in different regions of China, a national pediatric dialysis network, namely, International Pediatric Dialysis Network-China (IPDN-China) ( www.pedpd.org.cn ), was launched in 2012. METHODS: Original and updated information from the renal centers registered with the IPDN-China was collected between 2012 and 2016 from two sources, namely, the registry and the survey, and demographic features were analyzed. RESULTS: Due to promotion by the IPDN-China, the number of registered renal centers increased from 12 to 39 between 2012 and 2016, with a significant increase in the coverage of the Chinese administrative divisions (from 26.5 to 67.6%) (p < 0.01); and the coverage of the pediatric (0~14 years old) population increased to nearly 90% in 2016. The distribution of renal centers indicated that East China had the highest average number of registered centers per million population (pmp) 0~14-year-old age group. Seventeen relatively large dialysis centers were distributed across 14 divisions. Various modalities of renal replacement therapy (RRT) were available in most centers. The IPDN-China has promoted collaborations between dieticians, psychologists, and social workers on dialysis teams to provide better service to children with ESRD and their families. The proportion of centers with all three types of paramedic support (i.e., dieticians, psychologists, and social workers) as well as the proportion of centers with a partial paramedic team significantly increased between 2012 (25.0%) and 2016 (69.2%) (p < 0.05). In terms of the point prevalent cases of patients (aged < 18 years), data from the survey of 39 registered centers revealed that the number of children with ESRD who were on RRT was 578 (49% received a kidney transplant) at the end of 2016, which was more than that reported in previous surveys. Data from the registry showed that 349 dialysis patients had been enrolled as of the end of 2016. The median age at RRT start was 9.5 years, and the leading cause of ESRD was congenital abnormalities of the kidney and urinary tract (CAKUT). CONCLUSIONS: The IPDN-China has helped to promote the development of pediatric dialysis for ESRD in China by improving the organization of care for dialysis patients and increasing the availability and the quality of RRT for patients who need it. To improve knowledge about the epidemiology and outcomes of pediatric RRT around the country, a sustained effort needs to be made by the IPDN-China to increase the enrollment of dialysis patients and increase the number of registered centers in the future.

Reproductive strategy of the floating alga Ulva prolifera in blooms in the Yellow Sea based on a combination of zoid and chromosome analysis.

Green algal blooms have occurred in the Yellow Sea for 13 consecutive years since 2007. However, little is known about the reproductive strategy of the dominant species Ulva prolifera in the field. In particular, it is not clear whether the floating Ulva species are sporophytes or gametophytes, and if their life history is sexual or asexual. In this study, the life history type was determined based on the size, phototactic response, and flagella number for the zoids in at least two successive generations. In addition, chromosome observations were conducted to distinguish the gametophytes and sporophytes in the floating Ulva species. The results showed that the floating Ulva species were all sporophytes with sexual reproductive patterns, thereby indicating that this Ulva species always maintains vegetative growth from April to June during the early stage of the blooms. In addition, we found that the chromosome numbers were 18 for the diploid sporophytes and nine for the haploid male and female gametophytes. These results provide useful information to help understand the explosive growth of these green algal blooms.

Wearable Sensors Integrated with Virtual Reality: A Self-Guided Healthcare System Measuring Shoulder Joint Mobility for Frozen Shoulder.

Frozen shoulder is a common clinical shoulder condition. Measuring the degree of shoulder joint movement is crucial to the rehabilitation process. Such measurements can be used to evaluate the severity of patients' condition, establish rehabilitation goals and appropriate activity difficulty levels, and understand the effects of rehabilitation. Currently, measurements of the shoulder joint movement degree are typically conducted by therapists using a protractor. However, along with the growth of telerehabilitation, measuring the shoulder joint mobility on patients' own at home will be needed. In this study, wireless inertial sensors were combined with the virtual reality interactive technology to provide an innovative shoulder joint mobility self-measurement system that can enable patients to measure their performance of four shoulder joint movements on their own at home. Pilot clinical trials were conducted with 25 patients to confirm the feasibility of the system. In addition, the results of correlation and differential analyses compared with the results of traditional measurement methods exhibited a high correlation, verifying the accuracy of the proposed system. Moreover, according to interviews with patients, they are confident in their ability to measure shoulder joint mobility themselves.

Annual patterns of macroalgal blooms in the Yellow Sea during 2007-2017.

The world's largest macroalgal blooms caused by Ulva prolifera have occurred in the Yellow Sea for 11 consecutive years. The area covered by blooms has been approximately 500 km2 in previous years, while in 2017, the maximum area decreased significantly to 312 km2. In this study, we concluded that species competition between Ulva and Sargassum (fast rise of the golden tides), extreme high sea surface temperature and harvest for floating Ulva macroalgae were the three critical factors influencing the sharp reduction in covered area for blooms in 2017. In addition, analysis of annual variations of Pyropia aquaculture area in the Southern Yellow Sea over the past two decades revealed that a great expansion in "Sansha" regions was mainly responsible for the initial blooms in 2007, and that this expansion supported the great biomass of the blooms in following years. Based on these findings, we suggest comprehensive utilization of the macroalgal blooms is a feasible way to control them.

Rapid expansion of Ulva blooms in the Yellow Sea, China through sexual reproduction and vegetative growth.

Green algal blooms have occurred in the Yellow Sea for 11 consecutive years since 2007. A "seed bank" comprising micro-propagules including gametes, meiospores, and zygotes, played an important role in the rapid formation of a green tide. In the present study, germination differences among zygotes, meiospores, and gametes were examined. The growth ability and maturation period of alternating generations of sexual Ulva prolifera strains were also assessed. The zygote and meiospore germination rate was 91.67% and 80.29%, respectively, approximately three times greater than that of gametes (30%). In addition, the highest daily growth rate of sporophytes and gametophytes was 266.7% and 288.1%, respectively, and the maturation period of sporophytes and gametophytes was 35.7 and 31.3 days, respectively. These results indicate that sexual reproduction and vegetative growth are mainly responsible for the rapid expansion of macroalgal blooms in the Yellow Sea.

Variations of dominant free-floating Ulva species in the source area for the world's largest macroalgal blooms, China: Differences of ecological tolerance.

Species composition and seasonal variations of free-floating Ulva species were investigated in the source area of the world's largest macroalgal blooms during 2009-2015. Based on a combination of a morphological analysis and sequences of nuclear-encoded ITS and 5S rDNA spacer regions, the dominant species in the free-floating Ulva community at the early stage of green tides were Ulva compressa, Ulva flexuosa, and Ulva linza. The first appearance of Ulva prolifera on the sea surface was in mid-May and it dominated the floating Ulva community in June from 2009 to 2011. From 2012-2015, U. prolifera was not only the first species to appear on the sea surface but also the dominant species during the whole early stage of green tides. To explain the successional mechanism, the effects of environmental factors on the growth of four Ulva species were examined in the laboratory under different combinations of light intensity and temperature. It was found that the highest growth rate of U. prolifera was 44.9%/d, which was much higher than the other three Ulva species. The strong tolerance of U. prolifera to extreme conditions also helps it survive and bloom in the Yellow Sea.

The Effect of Augmented Reality and Virtual Reality on Inducing Anxiety for Exposure Therapy: A Comparison Using Heart Rate Variability.

Claustrophobia is an anxiety disorder characterized by the fear of enclosed spaces. Although medication treatment can effectively control symptoms, the effects quickly disappear once medication is discontinued. Many studies have shown that combining psychotherapy and medication is more efficacious than solely using medication. However, the weaknesses of the traditional psychotherapy are that it is time-consuming and expensive. Alternatively, vivo exposure therapy is proposed in which anxiety is gradually triggered with stimuli. Targeting claustrophobia is diagnosed using the traditional method, and this study established virtual reality (VR) and augmented reality (AR) environments consistent with claustrophobic characteristics, comparing the two using an experimental process to examine whether VR and AR environments are equally capable of triggering anxiety in participants. This study further analysed the efficacies of VR and AR by measuring changes in participant's heart rates variability (HRV) and examining data from survey questionnaires. HRV results indicated that the proposed VR system and AR system were both able to trigger anxiety. Furthermore, the AR environment produced a stronger experience for the participants and caused physiological reactions more evident than those caused by the VR environment. Regarding the anxiety questionnaire, the participants suggested that their anxiety was significantly higher in the VR environment than in the AR environment.

[Brain Protection of Muscone in Rats with Brain Injury].

OBJECTIVE: To observe cerebral protective effect of muscone (nasal administration) on traumatic brain injury model rats. METHODS: SD rats were divided into the sham-operation group, the model group, and the treatment groups according to random digit table, 50 in each group. Traumatic brain injury model was established by controlled cortical strike. Rats in the sham-operation group received surgery and anesthesia procedures only, with no strike. Muscone (1.8 mg/kg) was delivered to rats in the treatment group using in situ nasal perfusion, 30 min each time, twice daily for 7 successive days. Water content of brain tissue was detected in each group before intervention (T1), at day 3 of intervention (T2), day 5 of intervention (T3), and after intervention (T4), respectively. Expression levels of brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were detected using immunohistochemical analysis. RESULTS: Compared with the sham-operated group, water content of brain tissue increased (P < 0.05), and expression levels of NGF and BDNF decreased in the model group at T1, T2, T3, and T4 (P <0. 01). Compared with the model group, water content of brain tissue decreased (P < 0.05), and expression levels of NGF and BDNF increased (P < 0.01) in the treatment group at T1, T2, and T3. CONCLUSION: Nasal administration of muscone could reduce water content of brain tissue, alleviate cerebral edema, promote secretion of BDNF and NGF by olfactory ensheathing cells in traumatic brain injury rats.

Bone marrow mesenchymal stromal cells ameliorate angiogenesis and renal damage via promoting PI3k-Akt signaling pathway activation in vivo.

OBJECTIVE: The objective of this study was to investigate the effects of the intravenous transplantation of bone marrow mesenchymal stromal cells (BM-MSCs) on the repair of glomerular endothelia and angiogenesis in rats with chronic renal failure (CRF). Furthermore, the mechanism of BM-MSCs promoting angiogenesis was explored by detection of Akt and P-Akt protein expression in rat kidney tissue. MATERIAL AND METHODS: A rat model with CRF was established by adenine. Immature male Wistar rats were randomly divided into control group, model group and treatment group. Model group rats were injected with phosphate-buffered saline (PBS) via tail vein 24 h after the successful modeling, whereas the treatment group rats were injected with BM-MSCs. Eight weeks later, urine and blood were collected to assess 24-h proteinuria, serum creatinine (Scr) and blood urea nitrogen (BUN). We identified glomerular capillaries density using JG12 immunostaining. Levels of vascular endothelial growth factor (VEGF) were assayed using enzyme-linked immunosorbant assay (ELISA). We used Western blot to determine protein expression of p-Akt and Akt in renal tissues. RESULTS: Adenine induced chronic renal damage, as indicated by the mass proteinuria, deterioration of renal function and the histopathologic injury in tubules and interstitium. BM-MSCs signficantly increased capillary density and improved renal function and serum VEGF. Additionally, activation of Akt (i.e., P-Akt significantly increased) in the treatment group was increased obviously. CONCLUSION: BM-MSCs could alleviate the renal damages of adenine-induced CRF, reduce the excretion of proteinuria, increase the glomerular capillaries density, promote the secretion of VEGF and finally contribute to improve renal function. VEGF-induced angiogenesis is mediated through activating PI3k-Akt signaling pathway.

Adaptability of free-floating green tide algae in the Yellow Sea to variable temperature and light intensity.

In this study, the influence of temperature and light intensity on the growth of seedlings and adults of four species of green tide algae (Ulvaprolifera, Ulvacompressa, Ulva flexuosa and Ulvalinza) from the Yellow Sea was evaluated. The results indicated that the specific growth rate (SGR) of seedlings was much higher than that of adults for the four species. The adaptability of U. prolifera is much wider: Adult daily SGRs were the highest among the four species at 15-20 °C with 10-600 µmol · m(-2) · s(-1) and 25-30 °C with 200-600 µmol · m(-2) · s(-1). SGRs were 1.5-3.5 times greater than the other three species at 15-25 °C with 200-600 µmol · m(-2) · s(-1). These results indicate that U. prolifera has better tolerance to high temperature and light intensity than the other three species, which may in part explain why only U. prolifera undergoes large-scale outbreaks and floats to the Qingdao coast while the other three species decline and disappear at the early stage of blooming.

Traceable nano geometric structure measurement and international comparison.

The accuracy of geometric structure plays a key role to guarantee high quality of the nano function device and electronic device. In June 1998, the Consultative Committee for Length (CCL) of International Committee for Weights and Measures decided to carry out international comparisons of five different types of artifacts: Step height standards, 1D-gratings, line scales, 2D-gratings and line width standards. The paper described the activity of NIM in the international comparison measurement of first three items, include the characters of artifacts, the working principle of instruments, the measuring procedures, the calculation methods, the comparison results and the measurement uncertainty.

[Immunosuppression induced by measles virus in adult patients is not related to CD4+ CD25+ regulatory T cell induction].

OBJECTIVE: To investigate of the relationship of the immunosuppression induced by Measles virus in adult patients and CD4+ CD25+ regulatory T cell. METHODS: Thirty-four patients with measles and 27 healthy control subjects were included in this study. The whole blood was collected and CD4+ CD25+ cell and FoxP3+ cell were analyzed by flow cytometry, and CD4+ CD25- and CD4+ CD25+ T lymphocytes were isolated from PBMCs of patients with measles or healthy donors, CD4+ CD25- T cells were cultured in absence or presence of anti-CD3, or BCG, or live attenuated MV. The cell culture supernatant was collected after 72 hours and the concentration of IFN-gamma and IL-10 was determined. RESULTS: Compared to healthy donors, we observed a reduction of the number of white blood cells and lymphocytes in patients with measles, but there was not significantly different in the frequency of CD4+ CD25+ T cells and CD4+ CD25high T cells within the total CD4+ population in the blood. Treg from both measles patients and healthy controls significantly inhibited IFN-gamma production by CD4+ CD25- T cells in response to anti-CD3 stimulation. CONCLUSION: Induction and expansion of Treg may not represent a mechanism involved in the establishment of immune suppression by MV.