Search Results (14)

The evolution of baleen whales (Mysticeti) comprises two main phases, namely, (i) a Paleogene phase, which saw the diversification of stem lineages, and (ii) a Neogene phase, dominated by modern-looking, toothless, baleen-bearing forms in the monophyletic group Chaeomysticeti. These two phases are separated by a global turnover event coinciding with a gap—or “dark age”—in the mysticete fossil record. This dark age occurred between 23 and ~18 Ma and is apparently detected worldwide, except in Zealandia. Here, we report on a new mysticete fossil from the Lower Miocene (Burdigalian: ~19.2 Ma) strata of the Chilcatay Formation cropping out at the newly discovered locality of Cerro Tiza (East Pisco Basin, Peru), which represents a limited but precious testament from the last phase of the baleen whale dark age. Two previously mentioned, slightly geologically younger fossils from the same formation are also reappraised herein, revealing the occurrence of at least another baleen whale taxon in the upper Chilcatay strata—one that belongs in the mysticete crown group. Although the Early Miocene remains a problematic time interval for the fossil record of baleen whales, our new results encourage the search for mysticete fossils in the Lower Miocene strata of the East Pisco Basin, whose basin fill preserves a cornucopia of extraordinarily informative marine vertebrate fossils of the Cenozoic age, as well as in coeval deposits worldwide. Full article

The toothless oil stirring disk is vital in modern transmission technology, particularly in fields like aviation, aerospace, and nuclear power, significantly impacting equipment performance. Oil-stirring lubrication is widely used in internal systems due to its simplicity and high reliability, but oil-stirring losses during lubrication contribute to increased system temperatures, affecting lifespan and performance. Accurate simulation of the two-phase flow during the lubrication process of high-speed toothless oil stirring disks is crucial for extending the lubrication system service life. This paper proposes a dynamic modeling approach for the lubrication of high-speed toothless oil stirring disks, integrating the volume of fluid (VOF) model and the RNG k-ε turbulence model, alongside spring smoothing and dynamic mesh reconstruction techniques. The model explores fluid flow and oil distribution in high-speed, toothless oil stirring pans, investigating the effects of different stirring pan speeds and oil heights on lubrication performance. Results indicate that stirring pan speed and oil height are key to improving lubrication efficiency. At high speeds, centrifugal force and gravity cause the lubricating oil to detach from the stirring pan surface, continuing to splash due to inertia. At 3200 r/min and an oil level of 20 mm, a stable oil film forms in the gearbox. Higher stirring pan speeds generate greater turbulence, enhancing lubrication effectiveness. The findings offer theoretical insights for dynamic lubrication system modeling and support gearbox design and optimization in aerospace and similar fields. Full article

People who suffer from body integrity dysphoria (BID) feel a strong need to be disabled. The most common desire is for amputation or paralysis. Objectives: This study aims to gather the opinion of experts on which types of disabilities are included in BID, which therapies are useful and whether those affected should be supported in obtaining a disability. Methods: A questionnaire with 62 items and a flow chart were developed and sent to experts who have published work with regard to BID. Participants: 22 experts from 11 countries, mostly with an academic title and with an average age of 48.5 years, responded. Results: As expected, amputations and paralysis were clearly attributed to BID, other disabilities (toothlessness, incontinence, diabetes) received rather uncertain or negative scores. On average, those affected were not classified as mentally or psychiatrically ill. Neurological misconnection was considered the most likely cause. Experts did not think it was helpful to inform the health system or even the police about the desire to be disabled. Almost all experts supported the surgical solution of amputation by doctors. All participants believed that BID patients are aware of the limitations imposed by the desired disability. Finally, a flow chart is presented for diagnosis and therapy. Conclusions: The experts assume that the surgical solution is currently acceptable if it has been proven that the BID-affected person does not suffer from another mental disorder, there is a high level of suffering due to BID, other therapies have not been of any use and it is clear that the quality of life will actually increase as a result of achieving the disability. Full article

During the harvesting of cut-stem vegetables, the structural parameters of cutters have an important influence on the harvesting effect. Structural parameters of stalks directly affect the cutting effect of the cutter. The thickness of the stalk xylem has a strong influence on the cutting stability and cutting surface effect of the cutter. In this paper, the effect of the broccoli stalk xylem on conventional toothless cutters was investigated using broccoli stalks as the cutting object. It was found that a thicker xylem leads to shear force fluctuations, which in turn affects the smooth operation of the cutting device. Taking locust mouthparts as the research object, a bionic multi-tooth cutting method is proposed in this paper to obtain the contour curve based on the locust upper jaw cutting tooth lobe. By establishing the regression equation, the contour curve of the cutting teeth is fitted accurately. The cutter edge is designed with the locust’s maxillary incisive lobe as the bionic object. ANSYS software was used to simulate the cutting of a double disc cutter and broccoli stalk. The effect of each factor was analyzed by response-surface regression to determine the optimal cutter speed, machine forward speed, cutting inclination, blade overlap, and optimal cutting position. The cutting test is verified via broccoli stalks and a cutting test bench to further determine the cutting device operating parameters. The optimal operating parameters of the cutting device were 0.239 m/s forward speed, 30.974-degree cutting edge angle, 10.066 mm blade overlap, and 467.511 rpm. Full article

In this study, the process of ligating blood vessels via biodegradable Mg alloy hemostatic clips with toothless, transverse teeth, and embedded teeth was simulated through finite element analysis (FEA). The results showed that the transverse tooth clip caused the minimum stress (0.81489 MPa) to blood vessels. Furthermore, the effects of clips with transverse teeth of different parameters, including lower tooth length, tooth height, and tooth pitch, on clamped blood vessels were studied. The numerical simulation results showed that the three optimal parameters for clips with transverse teeth were 0.2, 0.1, and 0.1 mm, respectively. Then, the optimally designed clip based on the Mg–Nd–Zn–Zr alloy was manufactured and evaluated using immersion tests. Results from the corrosion behavior study showed that closed clips (0.118 ± 0.041 mg·cm⁻²·day⁻¹) corroded slightly faster than open clips (0.094 ± 0.041 mg·cm⁻²·day⁻¹). Moreover, micromorphological observations showed that no cracks appeared on the closed clips, indicating that the Mg alloy had excellent performance and avoided stress corrosion cracking (SCC). Thus, the new type of Mg alloy clip kept good blood vessel closure during FEA and exhibited no corrosion cracking during the degradation process, making it a promising candidate for applications with biodegradable hemostatic clips. Full article

Geometric morphometry has been widely used in decapods’ studies for taxonomic needs, and for eco-morphological adaptation and intraspecific variations recordings. Among the 40 species of the genus Hippolyte, the Mediterranean endemic Hippolyte sapphica is the only one with two distinct conspecific morphotypes, without intermediate forms: morph-A with a long, dentate and morph-B with a very short, toothless rostrum. Previous studies have shown that the “rostral loss” in morph-B seems to be controlled by a single pair of alleles, with a complete dominance of allele b, expressed in morph-B. We aim to elucidate morphotypes’ rostral pattern in relation to size, sex, and season. Shrimps were collected during two different (dry/wet) seasons from two sites: s.1 with a mixed (morph-A and B) and s.2 with a pure, unmixed (morph-A) species populations. After morph and sex identification, individuals were photographed and geometric morphometric analysis of rostrum was carried out on a set of landmarks. The data suggest that only morph-A rostral shape seems to be influenced by shrimp’s size, sex, and time of the year. Interestingly, two distinct morph-B clusters appear, which probably correspond to the homozygous and heterozygous state (BB and BA) of the gene site that controls the species morphotypes’ phenology. Full article

Background: Premature loss of primary teeth can occur as a consequence of dental trauma, neonatal tooth extraction, early childhood caries, or periodontal problems, or it can be a manifestation of systemic disease. This review aims to present systemic disorders that can lead to premature loss of deciduous teeth in children and to provide a comprehensive resource for clinical practice for both physicians and dentists. Methods: This study is a narrative review of original studies and case reports published in English and Polish between 1957 and 2021 that was conducted by searching electronic scientific resources: PubMed, Google Scholar, Web of Science, and Science Direct. The schema of the qualification process is represented by a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). In total, 196 articles were identified; after provisional assessment of the titles and abstracts by two reviewers, 46 were found to be relevant to the topic, including 1 review, 16 original papers, and 27 case reports regarding systemic disease resulting in premature tooth loss. Results: In this study, 16 systemic diseases were linked to premature primary tooth loss in children: Papillon–Lefèvre syndrome, mucocutaneous dyskeratosis, Coffin–Lowry syndrome, congenital adrenal hyperplasia, Langerhans cell histiocytosis, cherubism, hypophosphatasia, acatalasia, Chediak–Higashi syndrome, cyclic neutropenia, erythromelalgia, Down syndrome, Hajdu–Cheney syndrome, short bowel syndrome, leukocyte adhesion deficiency type 1 (LAD-1), and Wiedemann–Steiner syndrome (WSS). Full article

Brushless direct current (BLDC) permanent magnet (PM) synchronous motors are in high demand for ventilator applications owing to their high speed, high efficiency, and other significant features. However, it has become an important problem in eddy current loss calculations with high-speed motors, which leads to low motor (ventilator) life and PM demagnetization. This paper focuses on the eddy current loss calculation and the structure improvement design for the two-pole 90 W, 47,000 r/min toothless BLDC motor. First, the influencing factors of eddy current loss are comprehensively investigated, and a multiparameter improvement methodology is proposed accordingly. Second, by finite element analysis (FEA), the effective winding length ratio and the number of parallel wires were mainly researched for the winding, and the influence on the eddy current loss and the efficiency was determined, providing a reference for BLDC high-speed motors. This study has resulted in a 34.75% reduction in the winding losses, and a 4.6% increase in the efficiency of the improved model compared with the original design. Third, the new rotor structure is proposed, saving PM volume 15% more than original. THD of gap flux density is decreased 20.97%; the eddy current loss in the new rotor is decreased 22% more than original. Furthermore, by coupling simulation of the magnetic–thermal field, the maximum temperature of winding of the improved model is 13.4% lower than that of the original model at the thermal steady state. Finally, the electromagnetic and thermal properties simulation results were verified by testing the prototype. It is of great significance to the structure design and efficiency improvement of the BLDC high-speed motor. Full article

This paper presents an alternative system called the axial-flux dual-stator toothless permanent magnet machine (AFDSTPMM) system for flywheel energy storage. This system lowers self-dissipation by producing less core loss than existing structures; a permanent magnet (PM) array is put forward to enhance the air–gap flux density of the symmetrical air gap on both sides. Moreover, its vertical stability is strengthened through the adoption of an axial-flux machine, so expensive active magnetic bearings can be replaced. The symmetry configuration of the AFDSTPMM system is shown in this paper. Then, several parts of the AFDSTPMM system are optimized thoroughly, including stator windings, number of pole pairs and the PM parameters. Further, the performance of the proposed PM array, including back-EMFs, air–gap flux density, average torque, torque ripple and over-load capacity, are compared with the Halbach PM array and spoke PM array, showing the superiority of proposed configuration. Finally, 3D simulations were made to testify for the 2D analyses. Full article

This article is a literature review aimed at presenting the general state of knowledge in manufacturing engineering and materials engineering to develop engineering materials applied for endodontic treatment as filling materials. Particular attention was paid to theoretical analyses concerning the selection of methods for developing and obturating root canals and discussing the results of experimental studies available in the literature. These activities aimed to compare the importance of the most commonly used endodontic filling materials based on gutta-percha or polymeric polyester materials, commonly known as resilon, respectively. The motivation to take up this complex, multi-faceted topic in this paper is the extent of caries, periodontal disease, and other oral diseases in 3 to 5 billion people, often affecting toothlessness and contributing to an increase in the index of disability-adjusted life years (number). Endodontics is an important element of the authors’ concept of Dentistry Sustainable Development (DSD) > 2020. The principles of qualifying patients for endodontic treatment are discussed. The introduction of rotary tools, especially manufactured from Nitinol alloy, to develop root canals and the latest thermohydraulic and condensation techniques for obturation guarantee progress in endodontics. The “Digital Twins” methodology was used, rooted in the idea of Industry 4.0 and the resulting idea of Dentistry 4.0, as well as knowledge management methods, to perform experimental research in virtual space, concerning methods of developing and obturating the root canal and assessing the tightness of fillings. Microscopic visualization methods were also used. Significant factors determining the effectiveness of endodontic obturation are the selection of the filling material and the appropriate obturation method. The generalized dendrological matrix of endodontic filling materials considers the criteria of mechanical strength influencing the potential root fracture and the quality of root canal filling. The results of the SWOT point analysis (strengths and weaknesses, opportunities, threats) were also compared. For both filling materials, the weaknesses are much less than the strengths, while the threats are slightly less than the opportunities for the gutta-percha-based material, while for resilon the opportunities are much smaller than the threats. It requires the application of an appropriate development strategy, i.e., MAXI-MAXI in the case of a filling material based on gutta-percha and MAXI-MINI in the case of resilon. Therefore, the analysis of these experimental data does not indicate the real competitiveness of resilon for the gutta-percha-based material. This material deservedly maintains its strong position as the “Gold Standard of Endodontics”. Full article

Decision-makers, planners and administrators involved in different policy domains at different governance levels face the important challenge of fostering more balanced, sustainable and territorially integrated development. Well-designed, multi-level, multi-sector and multi-actor governance arrangements can play a key role in this process through orchestrating the interplay between different spheres, activities, actors and interests. In this paper, we examine the role of spatial planning in improving the relations between rural, peri-urban and urban areas. We analyse the strengths and limitations of spatial planning and explore the connections with territorial development. The methodology used for this analysis combines regional case studies in seven European locations—Ede, Frankfurt/Rhein-Main, Styria/Graz, Helsinki, Lisbon, Lucca and Mid Wales, with rapid appraisals, the analysis of published data, expert judgement and triangulation. We ask under which conditions spatial planning can induce more balanced, sustainable territorial relations, and look at the contribution planning can make to achieving sustainable development goals. The problem of ineffective (or toothless) plan implementation provides the entry point into the analysis and discussion. We illustrate why mutually beneficial relations between urban, peri-urban and rural communities (and territories) cannot simply be planned. Instead, these relationships need to be supported by strategies, policy instruments and governance arrangements that foster synergies between different actors and activities. The planning process itself needs to become more transparent and participatory. We conclude that the questions addressed in this article in an exploratory fashion merit further research especially as a more sustainable and territorially integrated development is becoming increasingly important in European policy making. Full article

This paper concerns the assessment of the current state of dentistry in the world and the prospects of its sustainable development. A traditional Chinese censer was adopted as the pattern, with a strong and stable support on three legs. The dominant diseases of the oral cavity are caries and periodontal diseases, with the inevitable consequence of toothlessness. From the caries 3.5–5 billion people suffer. Moreover, each of these diseases has a wide influence on the development of systemic complications. The territorial range of these diseases and their significant differentiation in severity in different countries and their impact on disability-adjusted life years index are presented (DALY). Edentulousness has a significant impact on the oral health-related quality of life (OHRQoL). The etiology of these diseases is presented, as well as the preventive and therapeutic strategies undertaken as a result of modifying the Deming circle through the fives’ rules idea. The state of development of Dentistry 4.0 is an element of the current stage of the industrial revolution Industry 4.0 and the great achievements of modern dental engineering. Dental treatment examples from the authors’ own clinical practice are given. The systemic safety of a huge number of dentists in the world is discussed, in place of the passive strategy of using more and more advanced personal protective equipment (PPE), introducing our own strategy for the active prevention of the spread of pathogenic microorganisms, including SARS-CoV-2. The ethical aspects of dentists’ activity towards their own patients and the ethical obligations of the dentist community towards society are discussed in detail. This paper is a polemic arguing against the view presented by a group of eminent specialists in the middle of last year in The Lancet. It is impossible to disagree with these views when it comes to waiting for egalitarianism in dental care, increasing the scope of prevention and eliminating discrimination in this area on the basis of scarcity and poverty. The views on the discrimination of dentistry in relation to other branches of medicine are far more debatable. Therefore, relevant world statistics for other branches of medicine are presented. The authors of this paper do not agree with the thesis that interventional dental treatment can be replaced with properly implemented prophylaxis. The final remarks, therefore, present a discussion of the prospects for the development of dentistry based on three pillars, analogous to the traditional Chinese censer obtaining a stable balance thanks to its three legs. The Dentistry Sustainable Development (DSD) > 2020 model, consisting of Global Dental Prevention (GDP), Advanced Interventionist Dentistry 4.0 (AID 4.0), and Dentistry Safety System (DSS), is presented. Full article

Dental deficiencies coexist with hearing loss, and dental treatment can improve hearing acuity. To prove that different dentition affects the transmission of acoustic vibrations through bone conduction, we prepared six dry human skulls to reconstruct teeth and soft tissues. We measured the transmission of vibrations from the maxilla to the cochlea, in the toothless jaw (TJ), jaw with lateral defects with frame dentures (FD), toothless jaw with complete dentures (CD), and jaw with reconstructed dentition (RD). Each skull was flexibly suspended. The maxilla was stimulated with the bone vibrator Radioear B71. The vibrations of the pyramid were measured perpendicularly using the Polytec PSV-400-M2 scanning vibrometer. Characteristics of frequencies differed simultaneously on the left (l) and right (r) side of each skull. In all states (from 234 Hz to 5 kHz), we identified 10–21 resonant (R) and 9–21 antiresonant (AR) frequencies unilaterally (+/− 5%). In about 30% of cases, they were each time inconsistent with the “physiological” state-RD. In the 500 Hz–2 kHz frequency range (necessary for understanding speech), the effective vibrations velocities vRMS (mm/s) near cochlea were significantly lower in RD than in tree states, where (depending on the dentures) the least energy reached cochlea in FD and the most in TJ. Full article

Access to justice is an irreplaceable complementary right. Without enforcement, environmental law would be ‘toothless’ in practice. Recently, China has made some significant progress in protecting the relevant parties’ right to access to justice in environmental matters. However, there are still some problems and challenges in the protection of this right in theory and in practice. To effectively realize this right, it is necessary to analyze the present situations and problems of the right in China from a legal perspective. This is done by introducing and analyzing the laws, regulations, policies, and practice concerning the right to access to justice in environmental matters in China. Specifically, this paper discusses the present situations of this right from several aspects. Based thereon, a brief problems analysis will be made. Some possible suggestions on how to better protect the right in China will be proposed from the perspectives of engaging, effectiveness and efficiency. These suggestions include empowering various parties with more capacity and possibilities; establishing a legal aid system and special fund; improving the exemption system and attorney fee transfer system; establishing a pre-litigation examination mechanism; and stimulating various parties’ potential roles. Full article