Round Head Research Articles

Experimental investigation of equilibrium and temporal scour around the round head of the rubble mound breakwater in case of breaking and non-breaking waves

In this study, local sediment movements caused by regular wave effects around the head section of rubble mound breakwater were investigated experimentally. The experiments were performed in a wave channel with a length of 33 m, a width of 3.6 m and a depth of 1.2 m. A plunger-type wave generator was located at the offshore side, generating regular waves of varying heights and periods. Uniform sandbed material of three different grain sizes was used, alongside two distinct breakwater slopes and six different wave characteristics. Experiments were performed under both breaking and non-breaking wave conditions. Time-dependent scour depth and water level measurements were determined by using measuring equipment working with an ultrasonic method. In the paper, new empirical relations were derived for temporal relative scour depths and the non-dimensional time scale parameter and the non-dimensional time scale parameter. The determination coefficient and scatter index of these derived relations were calculated and evaluated statistically. It was observed that the relations are in good agreement with those obtained from experiments. Additionally, the findings indicate that wave breaking significantly reduces the equilibrium scour depth.

Structure Design And Optimization Approach For Low RCS Screws

With the rapid development of radar stealth and detection technology, large numbers of screws and rivets have become a major factor that affecting the aircraft’s invisibility. This is because these components have a significant impact on the overall radar cross section of the aircraft, when the electromagnetic scattering characteristic of strong scattering sources is greatly reduced. By analyzing the scattering contribution of the head and body to the screw, it has been obtained that the geometric structure of the head plays a primary role in influencing the overall radar cross section of the screw. According to the scattering mechanism and stealth principle, a shape design method for the low RCS screw is proposed, and then we investigated the scattering characteristic of the octagonal, hexadecagonal, and circular head screws respectively. Furthermore, a structure optimization approach for low RCS screws is introduced which takes the angle of the incident wave into account. This has resulted in the development of a corresponding triangular screw with low detection capabilities. The simulation results show that within the operating frequency band of radar, the triangular head screw has a maximum RCS reduction of approximately 30.1dB compared to a traditional round head screw in [-90°,90°]. On average, there is a reduction of 12.6dB. The simulated results demonstrate the effectiveness and feasibility of the proposed design and optimization method for low RCS screw structures

Exploring Skull Shape Variation and Allometry Across Different Chicken Breeds

This study investigates skull shape variation and allometry among three different chicken breeds: Broiler, Lohman Brown, and Leghorn. Geometric morphometric analysis was employed to analyze skull morphology, focusing on facial bones and the neurocranium. The study aims to understand how skull shape differs between these breeds and how it relates to size variation. Results show significant differences in skull morphology among the chicken breeds. Broiler chickens exhibit a distinct skull shape, characterized by a more rounded head and a higher neurocranium compared to the other breeds. In contrast, Lohman Brown and Leghorn chickens show similarities in skull shape, with a more elongated appearance. Broiler chickens were found to be the smallest among the breeds studied, with statistical analysis confirming their distinguishability based on centroid size. In contrast, Lohman Brown and Leghorn chickens exhibited similar sizes, with no significant difference between them. Allometric analysis reveals that skull shape changes with size, particularly in the neurocranium and facial bones. These findings suggest that evolutionary adaptations and breeding practices have influenced the skull morphology of these chicken breeds. Overall, this study provides insights into the skull shape variation and allometry of different chicken breeds, highlighting the importance of considering both genetic and environmental factors in understanding morphological diversity in poultry.

The Etiology of Neuromuscular Hip Dysplasia and Implications for Management: A Narrative Review.

This study summarizes the current knowledge of the etiology of hip dysplasia in children with neuromuscular disease and the implications for management. This article is based on a review of development of the hip joint from embryology through childhood growth. This knowledge is then applied to selective case reviews to show how the understanding of these developmental principles can be used to plan specific treatments. The development of the hip joint is controlled by genetic shape determination, but the final adult shape is heavily dependent on the mechanical environment experienced by the hip joint during growth and development. Children with neuromuscular conditions show a high incidence of coxa valga, hip dysplasia, and subluxation. The etiology of hip pathology is influenced by factors including functional status, muscular tone, motor control, child's age, and muscle strength. These factors in combination influence the development of high neck-shaft angle and acetabular dysplasia in many children. The hip joint reaction force (HJRF) direction and magnitude determine the location of the femoral head in the acetabulum, the acetabular development, and the shape of the femoral neck. The full range of motion is required to develop a round femoral head. Persistent abnormal direction and/or magnitude of HJRF related to the muscular tone can lead to a deformed femoral head and a dysplastic acetabulum. Predominating thigh position is the primary cause defining the direction of the HJRF, leading to subluxation in nonambulatory children. The magnitude and direction of the HJRF determine the acetabular shape. The age of the child when these pathomechanics occur acts as a factor increasing the risk of hip subluxation. Understanding the risk factors leading to hip pathology can help to define principles for the management of neurologic hip impairment. The type of neurologic impairment as defined by functional severity assessed by Gross Motor Function Classification System and muscle tone can help to predict the risk of hip joint deformity. A good understanding of the biomechanical mechanisms can be valuable for treatment planning.

Effect of a powered and a manual toothbrush in subjects susceptible to gingival recession: A 36-month randomized controlled clinical study.

The objective of this long-term clinical study was to evaluate the influence of a newly developed powered toothbrush (PT) on the size and number of pre-existing gingival recessions (GR) in comparison to a manual toothbrush (MT). This was a prospective, single-blind, parallel-group, randomized controlled clinical study. Participants without periodontitis, but with at least two teeth (index teeth) showing GR ≥2 mm were randomized to brush either twice daily with a MT or with a PT with a linear magnetic drive causing the round brush head to produce gentle micro vibrations along with oscillating-rotating movements. Primary outcome parameter was the mean change of GR at the index teeth over 36 months. Totally 87 out of 92 participants completed the study (MT/PT: n = 42/n = 45). At the 36-month evaluation the mean (standard deviation) change of GR at index teeth differed significantly between MT 0.17 (0.77) and PT -0.10 (0.63) (p = 0.013). Furthermore, the amount of GR sites which improved ≥1 mm or remained stable during the study period did not differ between MT and PT, but the number of sites worsened ≥1 mm was significantly in favour for PT (MT 23 (25.5%) versus PT 10 (10.6%); p = 0.009). A binary logistic regression identified tooth type (OR = 2.991 for pre-/molar (1.096 [95% CI 1.002-8.933]; p = 0.050)) and manual brushing (OR = 3.341 (1.206 [95% CI 1291-8648]; p = 0.013)) as risk factors for recession impairment at the index teeth. There were no differences between groups for adverse events. In a population with pre-existing gingival recessions and consequently a high risk of developing further recession the PT seems to be favourable with regard to further development of GR.

Minimal Social Cues, Body Proportion, Head Shape, and Participant’s Gender on the Trustworthiness of Social Robots

Exploring and validating factors that may influence the trustworthiness of social robots is of great significance to improving the effect of human-robot interaction. The purpose of this study was to explore the impact of several design factors on people’s perceptions of the trustworthiness of social robots. The research variables were social cues (ie, watching-eyes configuration, control configuration, and neutral configuration), head shape (ie, round head and rectangular head), body proportion (ie, low body proportion and high body proportion), and participant’s gender (ie, male and female). Twelve static synthetic social robots were created and presented to the participants as digital pictures. A total of 175 participants took part in the experiment through the online survey via the convenience sampling method. The generated results were as follows: (1) The robots with round heads appear to be more trustworthy than those with rectangular heads. (2) Robots with high body proportion are considered to be more trustworthy than robots with low body proportion. (3) Minimal social cues and body proportion of robots also have a significant interaction effect on improving the trustworthiness of robots. In the watching-eyes configuration, high body proportion is considered more trustworthy than low body proportion. On one hand, the results of this study can provide a good reference for the appearance form of social robots in human-robot interaction to serve human beings, and on the other hand, it also lays a foundation for further exploring the influence of social cues elicited by a series of social robot appearances and social behaviors regarding the trustworthiness of social robots.

The Effect of the Lateral First Metatarsal Head Shape on Hallux Valgus in Forced Turnout in Pre-Pointe Female Ballet Dancers: A Pilot Study.

A rounded lateral first metatarsal head shape is associated with higher rates of hallux abducto valgus recurrence following corrective surgery; however, the effect of the lateral first metatarsal head shape on the hallux abduction angle (HAA) has not yet been explored in a nonpathologic, pre-pointe ballet dancer population. The primary purpose of this study was to investigate the effect of the lateral first metatarsal head shape on the HAA when pre-pointe female dancers force their turnout. Seventeen female, pre-pointe ballet students (mean age, 10.8 ± 0.95 years) participated in this study. Fluoroscopic images of each dancer's dominant foot were taken, and the lateral first metatarsal head shape was classified visually. Each dancer performed three consecutive stances of natural double-leg upright posture: both functional and forced turnout. HAAs were obtained by marking medial bony landmarks on paper and were compared to photographic measurements. No significant difference was found between the round and angular lateral first metatarsal head shape for the change in HAA from natural double-leg upright posture to forced turnout. Hallux abduction angle significantly increased by 4.6° (P < .001) in forced turnout compared to the natural double-leg upright posture for the photographic method, whereas the paper method demonstrated an increase of 2.6° (P = .007). No statistical differences were found between the paper and photographic methods in measuring the HAA for all stances. Our findings suggest no association between the HAA and lateral first metatarsal head shape; however, HAA does increase when a dancer assumes forced turnout. The paper method demonstrated similar reliability to the photographic method and shows the potential for future use as a clinical tool in assessing hallux abducto valgus.

离散元法 (EDEM) 仿真与参数优化： 低损高效玉米脱粒装置的设计与试验

Aiming at the problems of low threshing efficiency and high damage rate of current threshing devices. In this study, the operational form of the threshing drum and the structure of the threshing element were innovated, and a new threshing drum with low damage and high efficiency was designed. Using EDEM software, flexible body modeling of corn kernels, cobs and whole ears was carried out. The dynamic analysis of the corn threshing process was completed and the simulation parameters were further optimized. The optimum operating parameters were analyzed by orthogonal rotational tests and response surface method with a speed of 800 r/min for the threshing drum, a clearance of 10 mm for the concave plate and 30 mm for the threshing drum. The radius of the round head of the threshing element was 5 mm. The height of the threshing element was 60 mm. The final threshing efficiency was 98.78% and the damage rate of threshing was 0.62%. The results show that the new threshing device can meet the requirements of low-loss threshing devices for corn combine harvesters and can provide a theoretical basis for the development of the theory and technical system of corn plot combine harvesters in the future.

Comparative Evaluation of Different Endodontic Access Cavity Designs with Different Burs-An in vitro Experimental Insight into the Aspect of Fracture Resistance.

In vitro fracture resistance of extracted mandibular molars treated with various access cavity designs, including traditional endodontic cavity (TradAC), conservative/contracted endodontic cavity (ConsAC), ninja endodontic cavity (UltraAC), truss endodontic cavity (TrussAC), caries-driven access cavity (CariesAC), and intact teeth, is the focus of this study. Six groups of 20 mandibular molars, totaling 120, were used in the investigation. While the other five groups underwent various access cavity preparations, chemomechanical preparation, and obturation procedures before being repaired with composite resin, Group 1 was left unaltered (the control). A 6 mm round head tip was used to apply the fracture force, which was measured in newtons, at a crosshead speed of 1 mm/min until fracture developed. According to the current study, the intact control group had the maximum fracture resistance. The access cavity groups' mean values were maximum in CariesAC followed by ConsAC, TrussAC, UltraAC, and TraditonalAC respectively. While among the four minimally invasive designs, CariesAC showed a higher fracture resistance despite the results being statistically insignificant, TradAC had a significantly lower resistance than other conservative access cavity designs.

FRI668 Insulinoma As A Cause Of New Onset Hypoglycemic Episodes

Abstract Disclosure: S. Zahra: None. M.A. Abbas: None. R. Subramani: None. F. Manas: None. S. Yavuz: None. 37 years old female with a past medical history of hypothyroidism presented with complaints of shakiness, lightheadedness, and palpitations, relieved by eating. The physical examination was unremarkable. Fasting blood work showed low glucose of 41 mg/dl (70-99 mg/dl), normal insulin levels of 8.4 UIU/ ml (normal:1.9-23 UIU/ml), elevated proinsulin 21.1 pmol/ L (normal:&amp;lt;8.0 pmol/L), normal C Peptide 2.5 ng/ ml (normal:1.1-4.4 ng/ml), and negative for insulin antibody. Serum ACTH and cortisol levels were normal. Blood testing for hypoglycemia-inducing medications was negative. CT and MRI abdomen pelvis contrast was normal. She was prescribed to wear Dexcom to monitor her blood glucose round the clock. She continued to have low blood glucose, sometimes without symptoms and was rescued by the alarm. She underwent endoscopic ultrasound and was found to have a 10mm x 9mm ill-defined rounded pancreatic head mass with diffuse echogenicity of the pancreas. Biopsy of the mass revealed clusters of epithelial cells with neuroendocrine differentiation, compatible with insulinoma. She underwent surgical resection of the mass. She was also referred to genetic testing due to the association of pancreatic tumors with MEN syndrome. The diagnosis of Insulinomas is clinical as well as biochemical with presenting symptoms of Whipple’s Triad along with the presence of the following lab findings: hypoglycemia with plasma glucose of less than 50mg /dl, insulin greater than 5 UIU/L, C-Peptide greater than 0.2 nmol/L (0.6 ng/mL), Insulin/C-Peptide ratio of greater than 1.0, Proinsulin greater than 20pmol/L, and the absence of sulfonylurea metabolites in plasma or urine. Insulinoma is the most common pancreatic neuroendocrine and functional endocrine tumor of the beta cells of the pancreas with a prevalence of 1-4 people per million with equal gender distribution. They are mainly seen in the fifth decade of life but can occur at any age. They can occur sporadically or can be associated with MEN 1. Insulinomas are mostly benign, about 5-10% can be malignant. When to do medical vs surgical management? For benign insulinomas, surgical resection is preferred. For locally invasive and malignant tumors, aggressive surgical resection is performed, unless surgery is contraindicated for any other reason or patient refuses it. Medical treatment is reserved for the patients with diffuse Beta cell disease, multiple insulinoma and unresected malignant insulinoma. In the presence of unresectable metastatic disease; radiofrequency ablation, selective embolization, intraarterial chemotherapy, alone or in combination has been shown to be effective in controlling hypoglycemic episodes and improving quality of life. Octreotide, via inhibiting insulin secretion, normalizes the blood glucose levels. For better detection of hypoglycemia and adequate response to medical therapy, continuous glucose monitoring is helpful. Presentation: Friday, June 16, 2023

Ontogenetic skull variation in a shovel-headed amphisbaenian species.

Leposternon microcephalum is a species belonging to the Amphisbaenia, a group of burrowing reptiles. Amphisbaenia present various morphological and physiological adaptations that allow them to penetrate the ground and live underground, through a system of galleries and permanent chambers that they build themselves. Among the morphological adaptations in this group, those of the skull stand out as it serves as the main excavation tool. Four basic skull shapes are recognized: rounded, keeled, shovel-shaped, and spade-shaped. The skull of L. microcephalum belongs to this last type, which is considered the most specialized. The species inhabits soils that are highly compacted and difficult to penetrate. Among the species of Leposternon present in South America, L. microcephalum has the widest distribution, being found in all Brazilian biomes and neighboring countries such as Bolivia, Argentina, Paraguay, and Uruguay. The analysis of the skull of this species was carried out using three-dimensional geometric morphometrics (3D-GMM), a technique that allows comparative analysis, through robust statistical methods, of shape and its variations, using Cartesian coordinate data from a configuration of homologous landmarks. The technique allows the size and shape components of a structure to be analyzed separately. From an ontogenetic point of view, this methodology had also been used to investigate variations in Cynisca leucura, a member of the Amphisbaenidae with a rounded head. Our hypothesis is that the patterns of morphological differentiation in the skull, mainly in the intermediate and occipital regions, are similar in different Amphisbaenia species. Therefore, the objective of this study was to analyze cranial morphological variations in an ontogenetic series of L. microcephalum using 3D-GMM. Computed Tomographic scans of 13 specimens were analyzed: juveniles (N = 8) and adults (N = 5), based on 20 landmarks that characterize the skull. Principal components and regression analyses between shape (dependent variable) and size (independent variable) showed a clear difference between the cranial morphological pattern of juvenile individuals and that of adults. For instance, young specimens tend to have a dorsoventrally tall neurocranium, with the tip of the snout more anteriorly oriented and its dorsal border subtly curved. Dorsally, the parietal region is thicker and smoothly dome-shaped in juveniles. As in C. leucura, the variation was strongly correlated with the size change from juvenile to adult, indicating a dominant role for ontogenetic allometry in determining skull shape.

Role of Flexible Bronchoscopy using Biopsy Forceps as the Initial Attempt for Headscarf Pin Aspiration Extraction.

Flexible bronchoscopy is a less invasive procedure for extracting foreign bodies from the airways. However, studies on the extraction of headscarf pins are still very limited to determine the efficacy and safety of headscarf pin extraction using flexible bronchoscopy with biopsy forceps. This retrospective study was conducted at Persahabatan Hospital, Jakarta, Indonesia, on patients who had been treated in this hospital for headscarf pin extraction between January 2013 and February 2023. Fibreoptic bronchoscopy was performed under general anaesthesia. The pin was removed using Radial Jaw 4 mm single-use pulmonary biopsy forceps. The impacted sharp tip of the pin was freed first, and the proximal part of the pin body was gripped using biopsy forceps. Once a firm hold of the sharp end or the proximal part of the pin was secured, the bronchoscope and forceps were both slowly withdrawn under direct vision. Thirty-two cases with headscarf pin aspiration were managed by fibreoptic bronchoscopy. A total of 12 patients (37.5%) came without any respiratory complaints; however, an equal number complained of cough and 6 cases (18.7%) of haemoptysis. All the cases in which the pins were visible in the airway were found with the round head down and the sharp tip oriented superiorly in the airway and impacted in the mucosa. Fibreoptic bronchoscopy extraction succeeded in 31 cases (96.8%). Only one case was converted to surgery. There were no major complications. Fibreoptic bronchoscopy with biopsy forceps under general anaesthesia is safe and effective for the removal of headscarf pin aspiration.

The Effect of Neck and Shoulder Stabilization Exercises Using Slings on Posture of Women in Their 20s with Round Shoulder and Forward Head Posture

The Effect of Neck and Shoulder Stabilization Exercises Using Slings on Posture of Women in Their 20s with Round Shoulder and Forward Head Posture

P-039 Pregnancy outcomes and genetic analysis of globozoospermic patients: A case series and review of the literature

Abstract Study question How should men with globozoospermia be managed in Assisted Reproductive Technologies (ART)? Summary answer IMSI (intracytoplasmic morphologically selected sperm injection), without oocyte activators (OA) allows to obtain a live birth, even when there is a mutation of DPY19L2 gene. What is known already Globozoospermia is a rare syndrome found in less than 0.1% of the infertile population. It is characterized by the presence of spermatozoa with round heads devoid of acrosomes. Two main genes are involved in the transmission of the disease: SPATA 16 and DPY19L2. Only Assisted Reproductive Technologies (ART) such as ICSI (intra-cytoplasmic sperm injection) and IMSI, with or without OA allow these couples to obtain pregnancies. There are no live births described after IMSI without OA in patients with a DPY19L2 mutation. Study design, size, duration Four infertile couples followed in the Department of ART at the Poissy Hospital Center, were studied between 2011 and 2022.All patients had total globozoospermia. Three patients were tested for the DPY19L2 gene mutation. Patients were managed in ART with the IMSI technique without the use of OA. Participants/materials, setting, methods The first patient had a homozygous mutation of the DPY19L2 gene. Two live births were obtained after IMSI. The second patient was not DPY19L2 mutated. 2 IMSI were performed, resulting in a biochemical pregnancy. The third patient had a homozygous mutation of the DPY19L2 gene. An IMSI was performed without obtaining a pregnancy, a second attempt is scheduled soon. The fourth patient refused genetic testing and IMSI management. Sperm donation was performed without achieving pregnancy. Main results and the role of chance In this case series, we present the management of four globozoosperm couples in the Reproductive Biology and Andrology Department at the Poissy Hospital Center. We also present the first two live births after performing an IMSI, without OA, in a globozoospermic patient with a homozygous mutation of DPY19L2 gene. In fact, according to our review of the literature, 53 case reports or articles of patients having benefited from ART with or without OA have been reported in globozoospermic patients. In these couples, 60 children were born. However, no live births had been reported until now in couples managed in IMSI without OA, where men had globozoospermia with DPY19L2 mutation. Limitations, reasons for caution The use of OA to increase the membrane permeability of oocyte to calcium and increase fertilization rates. The highest number of live births in the globozoosperm population occurs after ICSI or IMSI with OA. There is no described live birth without the use of OA in a DPY19L2 mutated patient. Wider implications of the findings The use of OA remains debated and is not authorized in some countries. Although our study found low fertilization rates after IMSI, it’s possible to obtain live births. The selection of spermatozoa with an acrosome outline at high magnification is thus an interesting alternative to the use of oocyte activators. Trial registration number not applicable

Effects of the launch parameters on trans-phase stability performance and mechanism for submarine-launched missiles model

The impact of missile head shape, launch angle, and Fr number on the stability of trans-phase missiles was investigated, providing both experimental and theoretical support for designing diverse ballistic trans-phase weapons and aircraft. Through water-to-air trans-phase experiments and numerical calculations of missiles, deflection angle, velocity, and trajectory are obtained, while statistical and flow-field analyses reveal associated stability mechanisms. The research results indicate a good agreement between the experimental and numerical results. As the Fr number increases for the same head shape, the variations in transient deflection angle decrease. The deflection angle shows notable variations for different head shapes under the same Fr number. Specifically, the flat head demonstrates the highest deflection angle, followed by the 120° conical head, the 90° conical head, and finally the round head shape. Different head shapes lead to varying water film deformations and turbulent kinetic energy dissipations, resulting in differences in shedding vortex intensity and frequency. Launch angles cause variable component wall shear forces and fluid resistances, while changing the Fr number affects initial kinetic energy and energy dissipation, leading to missile model stability differences.

Study on the spatial regularity of rammed pits of the Ming Great Wall using 3D scanning technique and Random Forest algorithm

In Northwestern China, the Ming Great Wall generally involves multiple layers of rammed earth, and rammed pits with regular spatial characteristics are always distributed on the horizontal interfaces between rammed layers. Obviously, the spatial regularity of rammed pits cannot only reflect the level of ramming technique in the Ming dynasty, but also control the geotechnical properties of rammed layer interfaces (RLIs). Hence, in the present study, one typical RLI with visible rammed pits was obtained from the Ming Great Wall in Yongchang County, Northwestern China, and the corresponding point cloud data were collected by 3D scanning technique. Then, this RLI was reconstructed using numerous micro slopes in ArcGIS, and the distribution maps of micro-slope heights, angles, plan curvatures and profile curvatures were produced as well. Based on these distribution maps and Random Forest (RF) algorithm, those micro slopes which can reflect the true rammed pit morphology (called the representative micro slopes) were identified, and ten zones where the representative micro slopes concentrate were selected as effective analysis domains. Furthermore, within effective analysis domains, the contour lines were generated to show the outline features of rammed pits, and the values of micro-slope heights, angles, plan curvatures and profile curvatures were statistically analyzed to reveal the surface features of rammed pits. Moreover, the distribution features of rammed pits were exhibited by their centroid positions, which can be calculated by the corresponding contour line shapes. Ultimately, this study indicates that rammed pits of the Ming Great Wall show more regularity than randomness in terms of geometric shapes and spatial distribution. Concretely, the outlines of most rammed pits approximate the circular or elliptical shapes. All the rammed pit surfaces are rough rather than smooth, and most of them can be mathematically expressed by quadratic polynomial equations. As for the distribution features, rammed pits are overall distributed in the triangular shapes, and distances between the equivalent centroids of adjacent rammed pits range from 8.95 cm to 17.86 cm. These findings prove that standardized ramming technique was applied in the Ming dynasty, resulting in high-quality construction of the Great Wall. Meanwhile, the rammers used to compact earthen materials possess rounded heads. However, the imperfect polishing of rammers and the inevitable operational errors could also lead to slight spatial randomness of rammed pits.

基于 EDEM 的顶杆输送带式取苗机构优化设计

In the seedling extraction mechanism of the ejection type, because the ejector rod is in direct contact with the seedling substrate, the fragmentation rate of the seedling is high, the success rate is low, and the seedling effect is poor. In order to solve this problem, combined with the interaction between the ejector rod and the bowl seedling, this paper analyzes the working principle of the ejector rod conveyor belt seedling harvesting mechanism, and optimizes the design of the ejector rod conveyor belt seedling harvesting mechanism. By using the method of EDEM simulation analysis and orthogonal experiment, taking the breaking rate and success rate of bowl seedling as the test response index, the effects of ejector rod end form, ejector rod diameter and seedling extraction speed were studied, and the results were analyzed by range analysis and variance analysis to analyze the influence law of the interaction of various factors on bowl seedling extraction. The simulation results show that the crushing rate of bowl seedlings increases with the increase of seedling speed and the decrease of ejector diameter. Among the three different types of ejectors, the effect of round head ejector is the best. The best parameter combination of the seedling mechanism is the diameter of the ejector rod 10mm, the seedling speed 2m/s, and the ejector rod in the form of round head ejector rod. The verification experiment shows that the seedling extraction effect of the optimized seedling extraction mechanism is better than that of the original seedling extraction mechanism. The results show that when the best combination of working parameters is used to collect seedlings, the qualified rate of seedlings is not less than 90%, the fragmentation rate is not higher than 20%, and the seedling performance is relatively stable. The optimized seedling extraction mechanism can be used in the automatic dryland bowl seedling transplanter to meet the operational requirements of the automatic transplanter.

Preparation and evaluation in vitro release of sodium alginate/chitosan polyelectrolyte microparticles containing rifampicin and theoretical study using DFT methods

In this work, rifampicin-loaded sodium alginate/chitosan polyelectrolyte microparticles were prepared by the ionotropic gelation technique using CaCl2 as a cross-linking agent. The influence of different sodium alginate and chitosan concentrations on particle size, surface properties, and in vitro release behavior was studied. An infrared spectroscopy investigation verified the lack of any drug–polymer interaction. The microparticles prepared using (30, 50) mg of sodium alginate were spherical while when using 75 mg of sodium alginate, vesicles with round heads and tapered tails were formed. The results showed that the microparticle diameters were between (11.872–35.3645) µm. The amount of rifampicin released and the kinetics of drug release from microparticles were studied, and the results showed that by increasing the concentration of the polymer, the release of the rifampicin from the microparticles decreased. The findings showed that rifampicin release followed zero-order kinetics and that drug release from these particles is frequently influenced by diffusion. The electronic structure and characteristics of the conjugated polymers (sodium alginate/Chitosan) were examined using density functional theory (DFT) and PM3 calculations with Gaussian 9, using the B3LYP, and electronic structure calculations using 6–311 G (d,p). The HOMO and LUMO energy levels are determined as the HOMO's maximum and the LUMO's minimum, respectively. Communicated by Ramaswamy H. Sarma

Aviation Rivet Classification and Anomaly Detection Based on Deep Learning

The shortage of personnel and the high cost have become a major pain point in the current safety supervision work of the inspectors. Aiming at the problem that the aircraft maintenance inspector could not visit the scene in person during the epidemic, a remote safety supervision platform was built based on intelligent glasses and 5G network, and the real-time monitoring of the aircraft skin rivet status was realized. And a method of aviation rivet classification and anomaly detection based on deep learning algorithm was proposed. Firstly, according to the appearance of rivet head, the aviation rivet is classified, the data set of aviation rivet is made, and the aviation rivet classification and anomaly detection model are constructed. Evaluate the detection results from such indicators as confidence, precision, recall rate, and mAP and compare the algorithm with the detection results of Yolox-s, Yolox-m, Yolov5-s, Yolov5-m, and Yolov4. The results show that (1) the algorithm proposed in this paper can realize the classification of aviation rivets and the detection of abnormal conditions, the confidence of the detection results is more than 90%, and the average precision, recall, and AP value are above 95%, 85%, and 88%, respectively. (2) The order of rivet classification and abnormal detection effect from good to bad is Philips screws, round head rivets, flat head rivets, countersunk head rivets, blind rivets, and abnormal condition. (3) Compared with other algorithms, the aviation rivet classification abnormal target detection based on deep learning has absolute advantages in accuracy and speed.

Front Cover: Ligand‐Free Pd‐Catalyzed Reductive Mizoroki‐Heck Reaction Strategy for the One‐Pot Synthesis of Functionalized Oxygen Heterocycles in Deep Eutectic Solvents (Eur. J. Org. Chem. 3/2023)

The Front Cover illustrates the reaction conditions for the straightforward synthesis of oxygen heterocycles in Deep Eutectic Solvents. Similar to dandelions, which are objects of great natural beauty, design and efficiency in delivering fruits from their round heads, two Pd-catalysts work synergistically and efficiently in a choline chloride-based eutectic mixture to allow telescoped, one-pot reductive Mizoroki–Heck reactions between DHF or DHP and (hetero)aryl halides to successfully provide tetrahydrofuran or tetrahydropyran derivatives in up to 95 % yield. More information can be found in the Research Article by F. M. Perna, V. Capriati et al.