Design of inductive electrostatic boom spray system based on embedded closed electrode structure and droplet distribution test in soybean field.

The large water demand, insufficient deposition on the back of the leaf and the uneven distribution of droplets are the problems of traditional agricultural ground plant protection machinery, which leads to low agricultural control efficiency. Combined with the advantages of electrostatic spray technology and the characteristics of high working efficiency and low probability of droplets drift of ground sprayer, an inductive electrostatic boom spray system based on embedded electrode structure is designed and mounted on a large self-propelled boom sprayer for field testing. Based on the working characteristics of the fan nozzle and the analysis of the theory of charge, the inductive electrostatic spray device is designed. The performance of the device is tested and the rationality of the system design is verified by COMSOL numerical simulations, charge-to-mass ratio, and particle size distribution measurements. The spray deposition scanning software and the Box-Behnken experimental design method are used to analyze the spray droplet deposition rate and coverage density of the sprayer on the front and back of the target leaves. The results show that the embedded closed electrode structure designed in this paper can avoid the problem of electrode wetting, and the electric field generated by it is mainly concentrated in the spray liquid film area, and the intensity reaches 6~7 V/m. At the conventional application height (500 mm), the maximum charge-to-mass ratio is 2.91 mC/kg, and the average particle size is 168.22 µm, which is 12.87% lower than that of ordinary spray, when the spray pressure is 0.3 MPa and the electrostatic voltage is 12 kV. The results of field experiments show that the optimum combination of the working parameters with the spray speed is 8.40 m/s, the spray pressure is 0.35 MPa, the charging voltage is 11.50 kV, the amount of droplet deposition in the lower dorsal area of the blade is 1.44 µL·cm-2. This study can provide a certain basis for the application of electrostatic spray technology in ground sprayers.

Dynamics and ecological reassembly of the human gut microbiome and the host metabolome in response to prolonged fasting.

Introduction: Prolonged fasting is an intervention approach with potential benefits for individuals with obesity or metabolic disorders. Changes in gut microbiota during and after fasting may also have significant effects on the human body. Methods: Here we conducted a 7-days medically supervised water-only fasting for 46 obese volunteers and characterized their gut microbiota based on whole-metagenome sequencing of feces at five timepoints. Results: Substantial changes in the gut microbial diversity and composition were observed during fasting, with rapid restoration after fasting. The ecological pattern of the microbiota was also reassembled during fasting, reflecting the reduced metabolic capacity of diet-derived carbohydrates, while other metabolic abilities such as degradation of glycoproteins, amino acids, lipids, and organic acid metabolism, were enhanced. We identified a group of species that responded significantly to fasting, including 130 fasting-resistant (consisting of a variety of members of Bacteroidetes, Proteobacteria, and Fusobacteria) and 140 fasting-sensitive bacteria (mainly consisting of Firmicutes members). Functional comparison of the fasting-responded bacteria untangled the associations of taxon-specific functions (e.g., pentose phosphate pathway modules, glycosaminoglycan degradation, and folate biosynthesis) with fasting. Furthermore, we found that the serum and urine metabolomes of individuals were also substantially changed across the fasting procedure, and particularly, these changes were largely affected by the fasting-responded bacteria in the gut microbiota. Discussion: Overall, our findings delineated the patterns of gut microbiota alterations under prolonged fasting, which will boost future mechanistic and clinical intervention studies.

Error assessment and correction for extrusion-based bioprinting using computer vision method.

299Bioprinting offers a new approach to addressing the organ shortage crisis. Despite recent technological advances, insufficient printing resolution continues to be one of the reasons that impede the development of bioprinting. Normally, machine axes movement cannot be reliably used to predict material placement, and the printing path tends to deviate from the predetermined designed reference trajectory in varying degrees. Therefore, a computer vision-based method was proposed in this study to correct trajectory deviation and improve printing accuracy. The image algorithm calculated the deviation between the printed trajectory and the reference trajectory to generate an error vector. Furthermore, the axes trajectory was modified according to the normal vector approach in the second printing to compensate for the deviation error. The highest correction efficiency that could be achieved was 91%. More significantly, we discovered that the correction results, for the first time, were in a normal distribution instead of a random distribution.

Corrigendum: Bio-high entropy alloys: Progress, challenges, and opportunities.

[This corrects the article DOI: 10.3389/fbioe.2022.977282.].

Bio-high entropy alloys: Progress, challenges, and opportunities.

With the continuous progress and development in biomedicine, metallic biomedical materials have attracted significant attention from researchers. Due to the low compatibility of traditional metal implant materials with the human body, it is urgent to develop new biomaterials with excellent mechanical properties and appropriate biocompatibility to solve the adverse reactions caused by long-term implantation. High entropy alloys (HEAs) are nearly equimolar alloys of five or more elements, with huge compositional design space and excellent mechanical properties. In contrast, biological high-entropy alloys (Bio-HEAs) are expected to be a new bio-alloy for biomedicine due to their excellent biocompatibility and tunable mechanical properties. This review summarizes the composition system of Bio-HEAs in recent years, introduces their biocompatibility and mechanical properties of human bone adaptation, and finally puts forward the following suggestions for the development direction of Bio-HEAs: to improve the theory and simulation studies of Bio-HEAs composition design, to quantify the influence of composition, process, post-treatment on the performance of Bio-HEAs, to focus on the loss of Bio-HEAs under actual service conditions, and it is hoped that the clinical application of the new medical alloy Bio-HEAs can be realized as soon as possible.

Medical high-entropy alloy: Outstanding mechanical properties and superb biological compatibility.

Medical metal implants are required to have excellent mechanical properties and high biocompatibility to handle the complex human environment, which is a challenge that has always existed for traditional medical metal materials. Compared to traditional medical alloys, high entropy alloys (HEAs) have a higher design freedom to allow them to carry more medical abilities to suit the human service environment, such as low elastic modulus, high biocompatible elements, potential shape memory capability. In recent years, many studies have pointed out that bio-HEAs, as an emerging medical alloy, has reached or even surpassed traditional medical alloys in various medical properties. In this review, we summarized the recent reports on novel bio-HEAs for medical implants and divide them into two groups according the properties, namely mechanical properties and biocompatibility. These new bio-HEAs are considered hallmarks of a historic shift representative of a new medical revolution.

Computer Vision-Aided 2D Error Assessment and Correction for Helix Bioprinting.

Bioprinting is an emerging multidisciplinary technology for organ manufacturing, tissue repair, and drug screening. The manufacture of organs in a layer-by-layer manner is a characteristic of bioprinting technology, which can also determine the accuracy of constructs confined by the printing resolution. The lack of sufficient resolution will result in defect generation during the printing process and the inability to complete the manufacture of complex organs. A computer vision-based method is proposed in this study to detect the deviation of the printed helix from the reference trajectory and calculate the modified reference trajectory through error vector compensation. The new printing helix trajectory resulting from the modified reference trajectory error is significantly reduced compared with the original helix trajectory and the correction efficiency exceeded 90%.

Computer vision-aided bioprinting for bone research.

Bioprinting is an emerging additive manufacturing technology that has enormous potential in bone implantation and repair. The insufficient accuracy of the shape of bioprinted parts is a primary clinical barrier that prevents widespread utilization of bioprinting, especially for bone design with high-resolution requirements. During the last five years, the use of computer vision for process control has been widely practiced in the manufacturing field. Computer vision can improve the performance of bioprinting for bone research with respect to various aspects, including accuracy, resolution, and cell survival rate. Hence, computer vision plays a substantial role in addressing the current defect problem in bioprinting for bone research. In this review, recent advances in the application of computer vision in bioprinting for bone research are summarized and categorized into three groups based on different defect types: bone scaffold process control, deep learning, and cell viability models. The collection of printing parameters, data processing, and feedback of bioprinting information, which ultimately improves printing capabilities, are further discussed. We envision that computer vision may offer opportunities to accelerate bioprinting development and provide a new perception for bone research.

Bathing and toileting difficulties of older adults in rural China: the role of environment.

BACKGROUND: For older adults, difficulties in bathing and toileting are often the most prevalent in the index of Activities of daily living (ADL). This study aims to examine how environmental factors are associated with difficulty of bathing and toileting among older adults in rural China. METHOD: The data are from the 2014 Thousand-Village Survey (TVS), a national survey of Chinese rural residents of old age. The sample consists of 10,689 subjects, 55 years or older, from 536 villages across all provinces of China. Logistic regressions were applied to examine how difficulty of bathing and toileting was related to environmental factors such as geographic location, neighbourhood amenity, and related facilities of bathing and toileting. RESULTS: Older adults living in the Southern regions of China had lesser difficulty in bathing and toileting than those living in Northern China, controlling for other confounders. Better neighbourhood conditions also reduced the likelihood of having such disabilities. Persons who bathed indoors without showering facilities, in public facilities, and outdoors were significantly more likely to have bathing disability than those who showered indoors with facility. Rural older adults who used pedestal pans and indoor buckets for toileting were more likely to have toileting disability than those who used indoor squatting facilities. CONCLUSION: Environmental barriers were associated with functional disability among older adults in rural China, but the disabled individuals may change their environments to adapt to their functional capabilities. Our findings suggest that it is imperative to promote the use of showering facilities and pedestal pans for toileting in rural China.

Leisure Activity Engagement Among the Oldest Old in China, 1998-2018.

Objectives. To examine the trends of leisure activity engagement among the oldest old in China for the past 2 decades.Methods. Our panel data came from the Chinese Longitudinal Healthy Longevity Survey, which systematically asked respondents about their current participation in leisure activities over a 20-year period. The final sample contained 66 789 interviews from 1998 to 2018. We applied generalized estimating equations regression models in our analysis.Results. Compared with 1998, odds ratios of television watching among Chinese oldest old individuals increased by about 2 to 3 times in 2018. Meanwhile, the odds ratio of exercise declined by 24%, mostly in men; playing cards and mah-jongg declined by about 30% for men. Results also showed that reading became less popular in the oldest old, and Chinese women tended to do more housework than before.Conclusions. Our findings indicated that Chinese oldest old persons have become more sedentary and solitary in the past 2 decades. The negative trend in leisure activity engagement among the elderly Chinese population warrants policy attention, and the urgent development of public health interventions is required to reverse such trends.

Metabolite profiling of Huaiyang Medicago polymorpha with different mowing crops.

The main purpose of our study was to identify and compare secondary metabolites due to different mowing in order to make better use of Huaiyang Medicago polymorpha. The metabolite profiling of Huaiyang Medicago polymorpha with two mowing crops was performed using a rapid resolution liquid chromatography system with quadrupole time-of-flight mass spectrometer (RRLC-QTOFMS) followed by multivariate statistical analyses. Principal Component Analysis (PCA) results showed a clear distinction between two mowing crops. The major metabolites that contributed to mowing discrimination were identified. The results also showed that the content of major active compounds in Medicago polymorpha from the second crop are higher significantly than the first crop. This study suggests that the strategy is a reliable and simple method for the rapid discrimination of subtle variations due to different mowing crops.

Mechanical Respond and Failure Mode of Large Size Honeycomb Sandwiched Composites under In-Plane Shear Load.

The present work focuses on the in-plane shear respond and failure mode of large size honeycomb sandwich composites which consist of plain weave carbon fabric laminate skins and aramid paper core. A special size specimen based on a typical element of aircraft fuselage was designed and manufactured. A modified in-plane shear test method and the corresponding fixture was developed. Three large size specimens were tested. The distributed strain gauges were used to monitor the mechanical response and ultimate bearing capacity. The results show that a linear respond of displacement and strain appears with the increase of the load. The average shear failure load reaches 205.68 kN with the shear failure occurring on the face sheet, and the maximum shear strain monitored on the composite plate is up to 16,115 µÎµ. A combination of theoretical analysis and finite element method (FEM) was conducted to predict the shear field distribution and the overall buckling load. The out-of-plane displacement field distribution and in-plane shear strain field distribution under the pure shear loading were revealed. The theoretical analysis method was deduced to obtain the variation rule of the shear buckling load. A good agreement was achieved among the experiment, theoretical analysis, and FEM results. It can be concluded that the theoretical analysis method is relatively conservative, and the FEM is more accurate in case of deformation and strain. The results predicted by h element and p element methods are very close. The results of the study could provide data support for the comprehensive promotion of the design and application of honeycomb sandwich composites.

Twelve-week study of moxa smoke: occupational exposure in female rats.

OBJECTIVE: To assess the toxicity of moxa smoke in rats. METHODS: Forty-eight female Wister rats were randomly divided into 4 groups (n = 12/group) to simulate moxa smoke exposure in Chinese medicine clinics (CMCs): the control group, and three moxa-smoke exposed groups of PM10 mass concentrations 3-5, 7-9 and 27-30 mg/m3 , respectively. These concentrations were 1 × , 2-3 × , and 7-9 × fold the concentrations found in CMCs. Exposures continued for 12 weeks (200 min/d, 5 d/week). RESULTS: No deaths were noted. After the exposure, the body weights, ratios of organ weight to body weight, urinary parameters, hematological parameters, clinical chemistry parameters and microscopic examinations revealed no obvious toxicity. CONCLUSION: Moxa smoke did not induce toxic effects in female rats in the study. These findings provide new evidence to the toxicity of moxa smoke.

Repeated exposure to moxa-burning smoke: its acute and chronic toxicities in rats.

OBJECTIVE: To assess toxicities of the air in Chinese medicine clinics polluted by moxa-burning smoke due to moxibustion-derived burning products (MBP). METHODS: Both acute and chronic toxicity studies were conducted. For the acute toxicity study, five groups of Wistar rats (n = 16/group, male: female = 1∶1) were exposed to five different concentrations (95%, 90%, 85%, 80% and 75%, respectively) of MBP for 2 h. For the chronic toxicity study, another three groups of male rats (n = 21/group) were exposed to MBP in three concentrations (10%, 40% and 70%, respectively) and one control group exposed to clean air 20 min/d for 144 d. Routine examinations were performed and analyzed by analysis of variance and dose-response relationship. RESULTS: In the acute toxicity study, the number of dead rats in the 95%, 90%, 85%, 80% and 75% groups were 16, 13, 7, 6 and 3, respectively, with LD50 of 86.274% after or during the 2 h exposure. In the chronic toxicity study, MBP exposure induced a decline in activity of the rats. Rats in the 10% group showed no signs of toxicity, while those in the 40% MBP group showed toxicity effects on the body weights (P < 0.05) and lung. Rats in the 70% MBP group also presented with reversible damage in the blood coagulation system (P < 0.05). CONCLUSION: Exposure to 10% MBP, which is equivalent to 27.45 mg/m3, was under the critical threshold for male rats' safety. Exposure to MBP above that limit induced lung damage. MBP in clinics need to be reduced to a safe level with enhanced ventilation.

[Analysis and evaluation on the nutrition components of Huaiyang Medicago polymorpha with different mowing crops].

OBJECTIVE: Analyze and evaluate systematically on the nutrient component variations of Huaiyang Medicago polymorpha cultivated in autumn greenhouse with different mowing crops. METHODS: Cultivated all the Medicago polymorpha grops in six greenhouses in November 2013, mowed totally six times with every 30 days, finally collected all the mature part of the whole grass on the ground (seeds before and after threshing) and straws which amount to nine crops. After vacuum dried at low temperature then grinded into superfine powder. Details of sample moisture have been recorded during the whole process. Standard food nutrition ingredient detection method was adopted to make systematically comparative analysis on the nutrients. RESULTS: All the protein contents in the first six mowing edible crops of Huaiyang Medicago polymorpha were above 28. 5%. It contained 18 amino acids, 9 kinds of essential amino acids which amino acid pattern was close to human beings, limiting amino acids here were referred to tryptophan and methionine. The ultimate dietary fiber was between 24.6% and 28.4%, the fat content was between 4.0% and 6.0%. The crops also contained abundant vitamins, minerals and trace elements. The protein content of the first three mowing crops powder were 38.6%, 37.9% and 35.9%, the contents of fat content were 4.3%, 5.1% and 5.0%, the content of dietary fiber were 25.4%, 24.6% and 27.2%. CONCLUSION: The first six mowing crops of the Huaiyang Medicago polymorpha which cultivated in autumn greenhouse contained abundant nutrient ingredients especially high protein, high dietary fiber and low fat. And the corresponding nutrition ingredients and contents have not changed significantly with the increased mowed crops. The nutrient contents of all the crops in the seed mature period and hay straw fell sharply and showed no directly edible value.

[Effects of Blood Activating Wind Dissipating Acupuncture on Blood Pressure of Prehypertension Patients].

OBJECTIVE: To observe the effects of blood activating wind dissipating acupuncture (BAWDA) on blood pressure (BP) of prehypertension (PHT) patients. METHODS: Totally 60 PHT patients were assigned to the control group and the acupuncture group according to random digit table, 30 in each group. All patients were intervened by life style. BAWDA was additionally performed in patients in the acupuncture group for 6 weeks (30 times). The improvement of BP after intervened by acupuncture was observed. BP success rates and the proportion of PHT progressing to hypertension (HT) were also observed after 6-week intervention of acupuncture and at 1-year follow-up. RESULTS: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased after 6-week intervention in the acupuncture. The BP control rate was 56.7% (17/30 cases) in the acupuncture group vs.10.0% (3/30 cases) in the control group with statistical difference (chi2 = 14.70, P < 0.01). At 1-year follow-up BP success rate was 36.7% (11/30 cases) in the acupuncture group, remarkably higher than that of the control group [13.3%, (4/30 cases)] (chi2 = 4.36, P < 0.05). CONCLUSIONS: BAWDA showed BP regulating roles in a gradually stable decreasing tendency. It also could elevate BP success rate of PHT, and reduce the risk of PHT progressing to HT.

The effect of procyanidin on expression of STAT1 in type 2 diabetes mellitus SD rats with focal cerebral ischemia.

OBJECTIVES: Diabetes with cerebral infarction is a common disease that severely impacts health. This study investigated the effect of procyanidin (PC) on the expression of signal transducers and activators of transcription (STAT1) in type 2 diabetes mellitus SD rats with focal cerebral ischemia. We then explored the protective mechanisms of PC in type 2 diabetes mellitus SD rats with focal cerebral ischemia, to provide theory evidence for its clinical application. METHODS: We set up a type 2 diabetes mellitus-MCAO model, evaluated neurological function, and used immunohistochemistry methods to measure the activity of STAT1. RESULTS: The brain expression of STAT1 in rats of the sham-operation group was low, but more STAT1 positive cells were found in normal rats with ischemia and in rats with both type 2 diabetes and ischemia when groups were compared with the sham-operation group (p<0.01). Compared with rats that had type 2 diabetes and ischemia, the numbers of STAT1 positive cells after low, medium and high-doses of PC were all decreased (p<0.01), whereby the mid and high-dose groups showed a more substantial decrease (p<0.01) and with no variance between the two groups (p>0.05). CONCLUSIONS: These results indicate that PC has a neuroprotective effect on type 2 diabetes mellitus-MCAO; this may be through decreasing the expression of STAT1, which influences the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway that may inhibit apoptosis to relieve neurological impairment.