Experimental study of guided waves propagation characteristics under the changing temperatures

Structural Health Monitoring (SHM) plays an important role in ensuring the safe use of aerospace, architecture and other fields. At present, SHM based on piezoelectric and guided waves is a hot spot for real-time monitoring and nondestructive testing. However, the effect of environmental temperatures may mask the signal changes caused by damage and lead to failure of guided wave SHM methods. In this paper, the influence mechanism of the changing temperatures on the propagation characteristics of the guided wave is analyzed. Piezoelectric constants changed with the changing temperatures due to the amplitude variation of the guided wave with the changing temperatures. The effect of temperature on material properties of the plate structures will result in the influence of the guided wave propagation speed. An experiment is performed to study the propagation characteristics of the guided wave on an aluminium plate under changing temperatures. The experimental results indicate that the temperature can change the guide wave amplitude and velocity. At the same time, the temperature effect has the same variation trend at different frequencies, and the slopes of the linear fitting of the propagation characteristics of guided waves with the changing temperatures are also almost consistent

Growing Business in Live Commerce: A Tripartite Perspective and Product Heterogeneity

Live streaming becomes an important channel helping organizations and individual sellers boost their sales. Our research takes an integrated perspective and examines the simultaneous influences of streamers-, consumers-, and products-related factors on sales volume in live commerce. We apply multiple linear regression to analyze a panel data set collected from Taobao live in Double 11, 2020, which contained 34,925 product sales records. We find that streamers’ social capital, consumers’ engagement, and products’ live demonstration all significantly contribute to product sales volume. In addition, product heterogeneity matters in live commerce such that the effects of streamers’ social capital and products’ live demonstration on sales volume work only for experience products (not for search products) and for the products with less popular brands (not for the products with popular brands). Our research offers comprehensive insights for both researchers and practitioners on how to grow business in live commerce

Upscaling Stem to Community-Level Transpiration for Two Sand-Fixing Plants: Salix Gordejevii and Caragana Microphylla

The information on transpiration is vital for sustaining fragile ecosystem in arid/semiarid environment, including the Horqin Sandy Land (HSL) located in northeast China. However, such information is scarce in existing literature. The objectives of this study were to: (1) measure sap flow of selected individual stems of two sand-fixing plants, namely Salix gordejevii and Caragana microphylla, in HSL; and (2) upscale the measured stem-level sap flow for estimating the community-level transpiration. The measurements were done from 1 May to 30 September 2015 (i.e., during the growing season). The upscaling function was developed to have one dependent variable, namely sap flow rate, and two independent variables, namely stem cross-sectional area of Salix gordejevii and leaf area of Caragana microphylla. The results indicated that during the growing season, the total actual transpiration of the Salix gordejevii and Caragana microphylla communities was found to be 287 31 and 197 24 mm, respectively, implying that the Salix gordejevii community might consume 1.5 times more water than the Caragana microphylla community. For this same growing season, based on the Penman-Monteith equation, the total actual evapotranspiration for these two communities was estimated to be 323 and 229 mm, respectively. The daily transpiration from the upscaling function was well correlated with the daily evapotranspiration by the Penman-Monteith equation (coefficient of determination R2 0.67), indicating the applicability of this upscaling function, a useful tool for managing and restoring sand-fixing vegetations. 2017 by the authors

Molecular characterization and phylogenetic analysis of unusual x-type hmw glutenin subunits from 1s(l) genome of aegilops longissima

Wheat related diploid species Ae. longissima (2n=2x=14, (SSl)-S-l) has extensive storage protein variations that may provide useful gene resources for wheat quality improvement. In this work, five novel 1S(l)-encoded x-type high molecular glutenin subunits (HMW-GS) were identified and designated as 1S(l)x-123, 1S(l)x-129, 1S(l)x1-136, 1S(l)x2-136 and 1S(l)x2.2, respectively. Their complete open reading frames (ORFs) were cloned and sequenced by AS-PCR, which contained 2874 bp (956 aa) for 1S(l)x-123, 2946 bp (979 aa) for 1S(l)x-129, 2901 bp (965 aa) for 1S(l)x1-136, 2982bp (991 aa) for 1S(l)x2-136 and 2928 bp (974 aa) for 1S(l)x2.2. Molecular characterization demonstrated that five unusual subunits had greater repetitive domains resulted from a larger fragment insertion (74-113 aa). Particularly, 1S(l)x-129 had an extra cysteine residue at the position 109 due to a TAT -> TGT dot mutation, which may improve the formation of superior gluten macropolymer. Our results suggest that these unusual HMW-GS could be served as potential superior gene resources for improving wheat gluten quality. Phylogenetic analysis revealed that HMW-GS genes from Glu-1Sx genomes had close evolutionary relationships with those of Glu-1Dx genome while sequences from Ae. speltoides aligned with those of B genome

Spatiotemporal Distribution of Eutrophication in Lake Tai as Affected by Wind

One common hypothesis is that wind can affect concentrations of nutrients (i.e., nitrogen and phosphorus) and chlorophyll-a (Chl-a) in shallow lakes. However, the tests of this hypothesis have yet to be conclusive in existing literature. The objective of this study was to use long-term data to examine how wind direction and wind speed affect the spatiotemporal variations of total nitrogen (TN), total phosphorus (TP) and Chl-a in Lake Tai, a typical shallow lake located in east China. The results indicated that the concentrations of nutrients and Chl-a tended to decrease from the northwest to the southeast of Lake Tai, with the highest concentrations in the two leeward bays (namely Meiliang Bay and Zhushan Bay) in the northwestern part of the lake. In addition to possible artificial reasons (e.g., wastewater discharge), the prevalent southeastward winds in warm seasons (i.e., spring and summer) and northwestward winds in cool seasons (i.e., fall and winter) might be the major natural factor for such a northwest-southeast decreasing spatial pattern. For the lake as a whole, the concentrations of TN, TP and Chl-a were highest for a wind speed between 2.1 and 3.2 m·s-1, which can be attributed to the idea that the wind-induced drifting and mixing effects might be dominant in the bays while the wind-induced drifting and resuspension effects could be more important in the other parts of the lake. Given that the water depth of the bays was relatively larger than that of the other parts, the drifting and mixing effects were likely dominant in the bays, as indicated by the negative relationships between the ratios of wind speed to lake depth, which can be a surrogate for the vertical distribution of wind-induced shear stress and the TN, TP and Chl-a concentration. Moreover, the decreasing temporal trend of wind speed in combination with the ongoing anthropogenic activities will likely increase the challenge for dealing with the eutrophication problem of Lake Tai. © 2017 by the authors

Osteogenesis Capability and Degradation Property Evaluation of Injectable Biomaterials: Comparison of Computed Tomography and Ultrasound

Injectable biomaterials, which can be physically inserted into a target site without the use of surgery, have received increasing attention in tissue engineering during the last decade. There is also a growing need for quantitative evaluation of the injectable biomaterial directly and noninvasively. The objectives of this study are to originate a quantitative noninvasive technique for evaluation of in situ forming bone biomaterials and to validate the feasibility of diagnostic ultrasound images analysis technique. The potential of ultrasound for quantitative evaluation of tissue development was compared with computed tomography (CT) in vivo. A strong correlation was witnessed between ultrasound gray-scale values (GV) and volumetric mean of CT value (HUm) (r=0.95). Meanwhile, the volume of the material area could be estimated by ultrasound maximum cross-section pixel, which demonstrates a certain consistency with CT mask volume in 3D reconstruction images (r=0.87). In conclusion, ultrasound imaging, which is corresponding with the traditional CT, can be used to evaluate osteogenesis capability and degradation property of injectable biomaterials. It may be a noninvasive, nonradioactive, and effective aid to monitor ossification and reconstruction of biomaterials at the implant region for bone defect repair

Assessment of cataract surgical outcomes in settings where follow-up is poor: PRECOG, a multicentre observational study

Background Poor follow-up after cataract surgery in developing countries makes assessment of operative quality uncertain. We aimed to assess two strategies to measure visual outcome: recording the visual acuity of all patients 3 or fewer days postoperatively (early postoperative assessment), and recording that of only those patients who returned for the fi nal follow-up examination after 40 or more days without additional prompting. Methods Each of 40 centres in ten countries in Asia, Africa, and Latin America recruited 40–120 consecutive surgical cataract patients. Operative-eye best-corrected visual acuity and uncorrected visual acuity were recorded before surgery, 3 or fewer days postoperatively, and 40 or more days postoperatively. Clinics logged whether each patient had returned for the fi nal follow-up examination without additional prompting, had to be actively encouraged to return, or had to be examined at home. Visual outcome for each centre was defi ned as the proportion of patients with uncorrected visual acuity of 6/18 or better minus the proportion with uncorrected visual acuity of 6/60 or worse, and was calculated for each participating hospital with results from the early assessment of all patients and the late assessment of only those returning unprompted, with results from the fi nal follow-up assessment for all patients used as the standard. Findings Of 3708 participants, 3441 (93%) had fi nal follow-up vision data recorded 40 or more days after surgery, 1831 of whom (51% of the 3581 total participants for whom mode of follow-up was recorded) had returned to the clinic without additional prompting. Visual outcome by hospital from early postoperative and fi nal follow-up assessment for all patients were highly correlated (Spearman’s rs=0·74, p<0·0001). Visual outcome from fi nal followup assessment for all patients and for only those who returned without additional prompting were also highly correlated (rs=0·86, p<0·0001), even for the 17 hospitals with unprompted return rates of less than 50% (rs=0·71, p=0·002). When we divided hospitals into top 25%, middle 50%, and bottom 25% by visual outcome, classifi cation based on fi nal follow-up assessment for all patients was the same as that based on early postoperative assessment for 27 (68%) of 40 centres, and the same as that based on data from patients who returned without additional prompting in 31 (84%) of 37 centres. Use of glasses to optimise vision at the time of the early and late examinations did not further improve the correlations. Interpretation Early vision assessment for all patients and follow-up assessment only for patients who return to the clinic without prompting are valid measures of operative quality in settings where follow-up is poor

Clinical characteristics and related influencing factors of common rheumatic diseases concomitant with tuberculosis

ObjectiveTo explore the clinical characteristics and risk factors of common systemic rheumatism concomitant with tuberculosis (TB).MethodsA total of 3,906 patients of RA, SLE, and SS diagnosed in the People's Hospital of Sichuan Province from January 2007 to January 2017 were collected. One hundred and five patients with TB were included as TB group, including 42 RA, 41 SLE, and 22 SS patients. In the non-TB group, 84 RA, 82 SLE, and 44 SS patients were randomly selected during the same period.ResultsFever was the most common symptom among RA, SLE, and SS patients with TB, accounting for 83.3%, 92.7%, and 68.2%, respectively. Cough, weight loss or fatigue were the next common. RA patients with TB were mostly pulmonary TB (PTB), accounting for 64.3%. The proportion of PTB for SLE and SS were 46.3%, 59.01%, respectively. In TB group, 59% RA, 57% SLE, and 62% SS with PTB had two or more chest CT findings. There were 48 TB cases received both Interferon Gamma Release Assay (IGRA) and Tuberculin skin test (TST) with positive rates of 91.8%, 45.8%, respectively. The daily average dose of glucocorticoids within 1 year in TB group was higher than that in non-TB group of SLE patients, lower counts of CD4+ T cell count were found in TB group (P &lt; 0.05), while no such differences were found in RA and SS patients.ConclusionRA patients with TB are mainly pulmonary TB. For SLE and SS patients, the chance of PTB and extrapulmonary tuberculosis is similar. Daily average dose of glucocorticoids within 1 year may be a common risk factor for RA, SLE and SS patients developing TB. Decreased CD4+ T cell count may also be a risk factor for SLE patients with TB. Symptoms of RA, SLE, SS with TB, are similar with the primary disease or other infection. It is recommended to conduct both TST and IGRA to help diagnose TB

Microbiome and Metabolomics Reveal the Effects of Different Feeding Systems on the Growth and Ruminal Development of Yaks

The change in the feeding system can greatly improve the growth performance of the yak (Bos grunniens), an important livestock species in the plateau region. Here, we comprehensively compared the effects of different feeding systems on the growth performance and ruminal development of yaks, and investigated the effects of ruminal microorganisms and metabolites using the 16S rRNA gene sequencing and liquid chromatograph–mass spectrometer (LC-MS) technologies. We found that compared to traditional grazing feeding, house feeding significantly improved the growth performance (such as average daily gain and net meat weight) and rumen development of the yaks. At the genus level, the abundance of Rikenellaceae RC9 Gut group, Christensenellaceae R-7 group, Lachnospiraceae NK3A20 group, Ruminococcaceae UCG-014, and Prevotellaceae UCG-003 showed significant differences and was closely related to rumen development in the two distinct feeding systems. Also, metabolomics revealed that the change in the feeding system significantly affected the concentration and metabolic pathways of the related rumen metabolites. The metabolites with significant differences were significantly enriched in purine metabolism (xanthine, adenine, inosine, etc.), tyrosine metabolism (L-tyrosine, dopaquinone, etc.), phenylalanine metabolism (dihydro-3-caumaric acid, hippuric acid, etc.), and cAMP signaling pathway [acetylcholine, (-)-epinephrine, etc.]. This study scientifically support the house fattening feeding system for yaks. Also, our results provide new insights into the composition and function of microbial communities that promote ruminal development and in general growth of the yaks