Observation and analysis of diving beetle movements while swimming

The fast swimming speed, flexible cornering, and high propulsion efficiency of diving beetles are primarily achieved by their two powerful hind legs. Unlike other aquatic organisms, such as turtle, jellyfish, fish and frog et al., the diving beetle could complete retreating motion without turning around, and the turning radius is small for this kind of propulsion mode. However, most bionic vehicles have not contained these advantages, the study about this propulsion method is useful for the design of bionic robots. In this paper, the swimming videos of the diving beetle, including forwarding, turning and retreating, were captured by two synchronized high-speed cameras, and were analyzed via SIMI Motion. The analysis results revealed that the swimming speed initially increased quickly to a maximum at 60% of the power stroke, and then decreased. During the power stroke, the diving beetle stretched its tibias and tarsi, the bristles on both sides of which were shaped like paddles, to maximize the cross-sectional areas against the water to achieve the maximum thrust. During the recovery stroke, the diving beetle rotated its tarsi and folded the bristles to minimize the cross-sectional areas to reduce the drag force. For one turning motion (turn right about 90 degrees), it takes only one motion cycle for the diving beetle to complete it. During the retreating motion, the average acceleration was close to 9.8 m/s2 in the first 25 ms. Finally, based on the diving beetle's hind-leg movement pattern, a kinematic model was constructed, and according to this model and the motion data of the joint angles, the motion trajectories of the hind legs were obtained by using MATLAB. Since the advantages of this propulsion method, it may become a new bionic propulsion method, and the motion data and kinematic model of the hind legs will be helpful in the design of bionic underwater unmanned vehicles

Dynamics and hydrodynamic efficiency of diving beetle while swimming

Diving beetle, an excellent biological prototype for bionic underwater vehicles, can achieve forward swimming, backward swimming, and flexible cornering by swinging its two powerful hind legs. An in-depth study of the propulsion performance of them will contribute to the micro underwater vehicles. In this paper, the kinematic and dynamic parameters, and the hydrodynamic efficiency of the diving beetle are studied by analysis of swimming videos using Motion Capture Technology, combined with CFD simulations. The results show that the hind legs of diving beetle can achieve high propulsion force and low return resistance during one propulsion cycle at both forward and backward swimming modes. The propulsion efficiencies of forward and backward swimming are 0.47 and 0.30, respectively. Although the efficiency of backward swimming is lower, the diving beetle can reach a higher speed in a short time at this mode, which can help it avoid natural enemies. At backward swimming mode, there is a long period of passive swing of hind legs, larger drag exists at higher speed during the recovery stroke, which reduces the propulsion efficiency to a certain extent. Reasonable planning of the swing speed of the hind legs during the power stroke and the recovery stroke can obtain the highest propulsion efficiency of this propulsion method. This work will be useful for the development of a bionic propulsion system of micro underwater vehicle

Relationship between accumulated temperature and quality of paddy

In this paper, a model for controlling paddy drying by incorporating accumulated temperature is introduced and defined. Drying experiments using freshly harvested paddy were conducted at different levels of drying air parameters including temperature (T = 27°C, 31°C, 35°C, 39°C, and 43°C), relative humidity (RH = 45%, 50%, 55%, 60%, and 65%), initial moisture content (M0 = 17%, 19%, 21%, 23%, and 25%) and airspeed (V = 0.4, 0.5, 0.6, 0.7, and 0.8 m s−1). When T = 31°C, RH = 60%, M0 = 19%, and V = 0.5 ms−1, the crack additional percentage reached a minimum value of 0.508%, with the average precipitation rate at 0.719%·h. Further, an accumulated temperature and quality chart was provided in this paper. The x-coordinate of this chart is temperature, and the initial moisture content represents the y-coordinate. It covers the drying conditions of the actual dryer well and has a wide range of applicability for real-world environment. The model developed in this study not only provides a scientific reference for precise drying and intelligent control of paddy but also guide the actual drying operation

HPV prevalence and genotype distribution among women in Shandong Province, China: Analysis of 94,489 HPV genotyping results from Shandong's largest independent pathology laboratory.

BackgroundData regarding human papillomavirus (HPV) prevalence and genotype distribution are limited in Shandong Province, China. Therefore, we investigated the recent HPV prevalence and genotype distribution among females in Shandong and aimed to provide comprehensive data to guide HPV-based cervical cancer screening and HPV vaccination for this population of Chinese women.MethodsHPV testing results of 94,489 females were retrospectively reviewed and extracted from the database of Jinan KingMed Diagnostics, the largest independent pathology laboratory in Shandong Province, China. HPV was detected by a HPV genotyping panel from January 2011 to June 2017. The overall prevalence, age-specific prevalence, and genotype distribution were analyzed.ResultsA total of 26,839 cases (28.4%) were HPV-positive, with 4.3% positive for low- or undetermined-risk HPV (lr-/urHPV)-only, 18.1% positive for high-risk HPV (hrHPV)-only, and 6.1% positive for mixed lr-/urHPV and hrHPV infections. Single HPV infections accounted for 62.8%, while the rest were multiple HPV infections of two or more genotypes. HPV16 (5.8%), HPV52 (5.1%), HPV58 (3.5%), HPV51 (2.6%), and HPV56 (2.3%) were the five most common hrHPV genotypes; while HPV81 (2.8%), HPV53 (2.8%), and HPV6 (2.3%) were the three most common lr-/urHPV genotypes. HPV18 (1.7%) was only the ninth most common hrHPV genotype. HPV16 but not HPV52 was more common in single infections than in multiple infections. The distribution of both mixed lr-/urHPV and hrHPV as well as overall HPV infections demonstrated a bimodal pattern across age groups, of which the first peak appeared in the younger group and the second peak was found in older women. A similar age-specific distribution was observed in multiple infections of three or more subtypes as well. Moreover, the proportion of mixed lr-/urHPV and hrHPV infection significantly increased, while those of lr-/urHPV-only and hrHPV-only infections declined as the number of co-infections increased during the study period.ConclusionThis large daily clinical practice report shows that HPV prevalence and genotype distribution are different in this population, who had limited cervical cancer screening service, compared to those in developed countries. Therefore, different strategies should be developed for HPV-based cervical cancer screening and vaccine-based HPV prevention in Shandong Province

Previous cervical cytology and high-risk human papillomavirus testing in a cohort of patients with invasive cervical carcinoma in Shandong Province, China.

Currently, available data regarding previous cervical cytology and high-risk human papillomavirus (hrHPV) test results to detect invasive cervical cancer are limited and controversial in China. Therefore, this retrospective study in a population of Chinese women with invasive cervical carcinoma aimed to gain further insight into the roles of cytology and hrHPV testing in cervical cancer screening.A total of 1214 cases with a histological diagnosis of invasive cervical cancer were retrieved from the Pathology Database of Jinan KingMed Diagnostics (JKD) over a 5-year period. Previous cytology and hrHPV test results of 469 patients carried out within the year before cancer diagnosis were documented.A higher percentage of patients who had undergone prior screening had micro-invasive cervical carcinoma than patients who had no prior screening (25.4% vs. 12.1%, P < 0.001). Of the 469 patients with available prior screening results, 170 had cytology alone, 161 had hrHPV testing alone, and 138 had both cytology and hrHPV testing. There was a significantly lower percentage of hrHPV-positive cases with adenocarcinoma than with squamous cell carcinoma (77.8% vs. 96.4%, P = 0.001). The hrHPV test showed a significantly higher sensitivity than cytology alone (94.4% vs. 85.3%, P = 0.006). The overall sensitivity of the combination of cytology and hrHPV testing (98.6%) was much higher than that of cytology alone (P < 0.001) but only marginally higher than that of hrHPV testing alone (P = 0.058).The results revealed that prior cervical screening can detect a significantly larger number of micro-invasive cervical cancers. The hrHPV test can provide a more sensitive and efficient strategy than cytology alone. As the addition of cytology to hrHPV testing can only marginally increase the efficiency of the hrHPV test, hrHPV testing should be used as the primary screening approach, especially in the low-resource settings of China

Precession-driven changes in air-sea CO2 exchange by East Asian summer monsoon in the Western Tropical Pacific since MIS 6

Surface waters of the modern Western Tropical Pacific (WTP) are in equilibrium with atmospheric CO2. However, air-sea exchange of CO2 in this region may have been modulated in the past by oceanic-atmospheric fluctuations in the tropical Pacific such as the East Asian monsoon and the El Niño-Southern Oscillation (ENSO) and extratropical mode waters such as Antarctic Intermediate Water. Thus, understanding controls on the sea-surface carbonate system in the WTP is important for forecasting future carbon-cycle changes in this region. Here, we reconstruct sea-surface pH and pCO2 since Marine Isotope Stage 6 (MIS 6; 155 ka) based on B/Ca ratios of the planktic foraminifer Globigerinoides ruber (white) in sediment Core MD06–3052 from the western Philippine Sea, and we then calculate the difference between oceanic and atmospheric pCO2 (ΔpCO2(sw-atm)) in order to evaluate the history of air-sea CO2 exchange. ΔpCO2(sw-atm) changes were strongly modulated by the ~20-kyr precession cycle. The results of cross-spectral analysis demonstrate a close connection between the East Asian summer monsoon (EASM) and air-sea CO2 exchange since MIS 6, demonstrating that precession-driven EASM can affect air-sea CO2 exchange through regulation of surface productivity and thermocline depth. In contrast, the East Asian winter monsoon (EAWM) and ENSO-like conditions are not major influences on air-sea CO2 exchange in the study area at precession-band frequencies. In addition, enhanced upwelling of Southern Ocean-sourced deepwater rich in dissolved inorganic carbon (DIC) affected the upper water column during transitions from cold to warm stages (i.e., deglaciations). In conclusion, these findings suggest that orbital precession influences can affect oceanic conditions not only through climate change and biological processes but also through sea-surface carbonate chemistry

Cervical cancer histological subtypes in the current study.

<p>Cervical cancer histological subtypes in the current study.</p

Results of the combination of cytology and hrHPV testing within the year prior to the histological diagnosis of invasive cervical cancer.

<p>Results of the combination of cytology and hrHPV testing within the year prior to the histological diagnosis of invasive cervical cancer.</p

Comparison of the results of cytology, hrHPV testing, and their combination within the year prior to the histological diagnosis of invasive cervical cancer.

<p>Comparison of the results of cytology, hrHPV testing, and their combination within the year prior to the histological diagnosis of invasive cervical cancer.</p