bluuebunny/crossref_metadata_2025 huggingface dataset:
Consensus Tracking Control of Multiple Unmanned Aerial Vehicles Subject to Distinct Unknown Delays
Authors: Campos-Martínez Sandy-Natalie , Hernández-González Omar , Guerrero-Sánchez María-Eusebia , Valencia-Palomo Guillermo , Targui Boubekeur , López-Estrada Francisco-Ronay
Published: May 2024

This article deals with the consensus tracking problem for multi-agent systems (MAS) under the influence of unknown time-varying delays. Each agent of the MAS is a quadrotor unmanned aerial vehicle (UAV) represented as a linear continuous-time system. The main objective of this paper is the stabilization of multi-agent systems where the control input is affected by unknown time-varying delays, which are assumed to be upper-bounded, and where these bounds are not required to be known. The proposed observer-based control scheme guarantees the consensus tracking of multi-UAV systems with the desired H∞ performance, which adds a further level of mitigation of unknown delays present in MAS systems by minimizing the H∞ norm, which measures the maximum gain from the disturbance to the controlled output of the system. For each UAV agent, an unknown input observer is employed to isolate the unknown time-varying delays in the state estimation process. With the use of an unknown input observer-based consensus tracking control, sufficient conditions are derived to ensure that all follower UAVs can reach a consensus with the leader, despite the presence of distinct unknown time-varying delays. The stability of the proposed scheme is proven using Lyapunov theory for the leader and follower agents. Finally, numerical examples are provided to illustrate the effectiveness of the proposed method.
Natural Characteristics of a Marine Two-Stage Tandem Hybrid Planetary System
Authors: Zhao Xingfu , Yue Zongxiang , Qu Jianjun , Dzianis Marmysh , Wang Yanzhong
Published: May 2024

This study focuses on a marine two-stage tandem hybrid planetary system. Natural frequencies and vibration modes are determined using a translational–torsional coupled dynamic model. Based on the motion characteristics of the transmission system, free vibration is categorized into three typical modes. The parameter sensitivity of natural frequencies is computed, and the effects of structural parameters such as unequally spaced planet, mesh stiffness, planet mass and rotational inertia on the natural frequencies are analyzed. Utilizing the coupling factor, the mode transition criterion for the natural frequencies response to parameters is formulated. The results demonstrate that the vibration modes of the two-stage tandem hybrid planetary system can be classified as the fixed-axis train vibration mode, the differential train vibration mode, and the coupled vibration mode. Unequally spaced planet primarily disrupts vibration modes without significantly affecting natural frequencies. In contrast, the effects of mesh stiffness, planet mass and rotational inertia on the modes are opposite to those of unequally spaced planets. The validity of the parameter sensitivity and mode transition criterion is substantiated through illustrative examples.
Static Bipartite Consensus Problems of Heterogeneous Signed Networks
Authors: Ma Yu , Zhang Yi , Li Jinchao , Du Mingjun , Ji Peng
Published: May 2024

This paper aims to study the distributed control problems of heterogeneous signed networks whose communication topologies are undirected. A distributed control protocol is designed based on neighboring state information. With this protocol be employed, the convergence results of the heterogeneous signed network are provided. It is shown that the heterogeneous signed network can achieve the static bipartite consensus (respectively, state stability) if and only if the signed graph is structurally balanced (respectively, unbalanced). The associated convergence analyses can be developed by constructing a suitable Lyapunov function. In addition, two simulation examples are presented to validate the correctness of the obtained results.
Atypic Retinitis Pigmentosa Clinical Features Associated with a Peculiar CRX Gene Mutation in Italian Patients
Authors: Piergentili Marco , Spagnuolo Vito , Murro Vittoria , Mucciolo Dario Pasquale , Giorgio Dario , Passerini Ilaria , Pelo Elisabetta , Giansanti Fabrizio , Virgili Gianni , Sodi Andrea
Published: May 2024

Purpose: To describe an atypical phenotypic pattern of late-onset retinitis pigmentosa (RP) due to the same specific c.425A>G (p.Tyr142Cys) heterozygous mutation in the cone–rod homeobox gene (CRX gene) in two unrelated Italian patients. Case 1: A 67-year-old woman (P.P.) was incidentally diagnosed with sector RP at the age of 50. The patient was initially asymptomatic and did not have any family history of retinal dystrophy. Fundus examination showed the presence of typical retinal pigmentary deposits with a peculiar pericentral/sector distribution. Genomic sequencing disclosed the missense mutation c.425A>G (p.Tyr142Cys) in the CRX gene. During the follow-up period of 7 years, the patient maintained good visual acuity and complained only of mild symptoms. Case 2: A 76-year-old man (P.E.) presented with nyctalopia and visual field constriction since the age of 50. Fundus examination showed the presence of retinal pigment deposits with a concentric pericentral and perimacular pattern. A full-field electroretinogram (ffERG) showed extinguished scotopic responses and reduced abnormal photopic and flicker cone responses. Genomic sequencing identified the same missense mutation, c.425A>G (p.Tyr142Cys), in the CRX gene. Similarly to the first case, during the whole follow-up of 7 years, the visual acuity remained stable, as did the visual field and the patient’s symptoms. Conclusions: We report the first cases of late-onset retinitis pigmentosa related to a specific heterozygous CRX gene mutation in exon 4. We also report two atypical phenotypic RP patterns related to mutations in the CRX gene.
Comparison of the Analgesic Effect of Pericapsular Nerve Group Block and Lumbar Erector Spinae Plane Block in Elective Hip Surgery
Authors: Küçük Onur , Sağ Fatih , Eyrice Ali , Karadayı Selman , Alagöz Ali , Çolak Alkin
Published: May 2024

Background and Objectives: The aim of this study was to compare the effectiveness of pericapsular nerve group (PENG) and lumbar erector spinae plane (L-ESP) blocks, both administered with a high volume (40 mL) of local anesthetic (LA), for multimodal postoperative analgesia in patients undergoing hip surgery. Materials and Methods: This was a prospective, double-blind, randomized study that included 75 adult patients who were divided into three equal groups: control, PENG, and L-ESP. The study compared pain intensity, morphine consumption, time to first morphine request, and postoperative satisfaction between the control group, which received standard multimodal analgesia, and the block groups, which received PENG or L-ESP block in addition to multimodal analgesia. The numerical rating scale (NRS) was used to measure pain intensity. Results: The results showed that the block groups had lower pain intensity scores and morphine consumption, a longer time to the first morphine request, and higher postoperative satisfaction compared to the control group. The median maximum NRS score during the first 12 h was four in the control group, two in the PENG group, and three in the L-ESP group. The control group (21.52 ± 9.63 mg) consumed more morphine than the two block groups (PENG, 11.20 ± 7.55 mg; L-ESP, 12.88 ± 8.87 mg) and requested morphine 6.8 h earlier and 5 h earlier than the PENG and L-ESP groups, respectively. The control group (median 3) had the lowest Likert satisfaction scores, while the PENG group (median 4) had the lowest NRS scores (L-ESP, median 4). Conclusions: The application of PENG or L-ESP blocks with high-volume LA in patients undergoing hip surgery reduces the need for postoperative analgesia and improves the quality of multimodal analgesia.
Racial Disparities in Cardiovascular and Cerebrovascular Adverse Events in Patients with Non-Hodgkin Lymphoma: A Nationwide Analysis
Authors: Uttam Chandani Kanishka , Agrawal Siddharth Pravin , Raval Maharshi , Siddiq Sajid , Nadeem Ahmed , Chintakuntlawar Ashish V. , Hashmi Shahrukh K.
Published: May 2024

Background and Objectives: Non-Hodgkin lymphoma (NHL) has the sixth-highest malignancy-related mortality in the United States (US). However, inequalities exist in access to advanced care in specific patient populations. We aim to study the racial disparities in major adverse cardiovascular and cerebrovascular events (MACCEs) in NHL patients. Materials and Methods: Using ICD-10 codes, patients with NHL were identified from the US National Inpatient Sample 2016–2019 database. Baseline characteristics, comorbidities, and MACCE outcomes were studied, and results were stratified based on the patient’s race. Results: Of the 777,740 patients with a diagnosis of NHL, 74.22% (577,215) were White, 9.15% (71,180) were Black, 9.39% (73,000) were Hispanic, 3.33% (25,935) were Asian/Pacific Islander, 0.36% (2855) were Native American, and 3.54% (27,555) belonged to other races. When compared to White patients, all-cause mortality (ACM) was significantly higher in Black patients (aOR 1.27, 95% CI 1.17–1.38, p < 0.001) and in Asian/Pacific Islander patients (aOR 1.27, 95% CI 1.12–1.45, p < 0.001). Sudden cardiac death was found to have a higher aOR in all racial sub-groups as compared to White patients; however, it was statistically significant in Black patients only (aOR 1.81, 95% CI 1.52–2.16, p < 0.001). Atrial fibrillation (AF) risk was significantly lower in patients who were Black, Hispanic, and of other races compared to White patients. Acute myocardial infarction (AMI) was noted to have a statistically significantly lower aOR in Black patients (0.70, 95% CI 0.60–0.81, p < 0.001), Hispanic patients (0.69, 95% CI 0.59–0.80, p < 0.001), and patients of other races (0.57, 95% CI 0.43–0.75, p < 0.001) as compared to White patients. Conclusions: Racial disparities are found in MACCEs among NHL patients, which is likely multifactorial, highlighting the need for healthcare strategies stratified by race to mitigate the increased risk of MACCEs. Further research involving possible epigenomic influences and social determinants of health contributing to poorer outcomes in Black and Asian/Pacific Islander patients with NHL is imperative.
Defining Trimester-Specific Reference Intervals for Thyroid Hormones: Insights from a Bulgarian Monocenter Study
Authors: Yanachkova Vesselina , Staynova Radiana , Naseva Emilia Krassimirova
Published: May 2024

Background and Objectives: Pregnancy introduces various interfering factors that, alongside individual variations, impact the assessment of thyroid function tests. This underscores the necessity of defining trimester-specific reference intervals for thyroid-stimulating hormone (TSH) levels. Differences in population characteristics, including ethnicity, socio-economic factors, iodine prophylaxis, and obesity, emphasize the need to establish trimester-specific TSH ranges for women of reproductive age in the respective region or center. The aim of the present study was to establish first- and second-trimester-specific reference intervals for TSH and free thyroxine (FT4) in a relevant pregnant population. Materials and Methods: A retrospective monocenter analysis utilized the electronic database of Ob/Gyn Hospital “Dr. Shterev”, Sofia, Bulgaria. The analysis involved data from 497 pregnant and 250 non-pregnant women, all without evidence of thyroid dysfunction or a family history thereof, no indication of taking medication interfering with thyroid function, no evidence of levothyroxine treatment, and no history of sterility treatment. To establish the limits of the TSH reference range, the percentile method was applied using a bootstrapping procedure following the recommendations of the International Federation of Clinical Chemistry (IFCC). Results: Trimester-specific reference intervals for TSH and FT4 in our center were established as follows: first trimester—0.38–2.91 mU/L, FT4-12.18–19.48 pmol/L; second trimester—0.72–4.22 mIU/L and 9.64–17.39 pmol/L, respectively. We also established the normal reference range for the non-pregnant control group, which is similar to that applicable in our laboratory. Conclusions: Our results differ from the fixed limits recommended by the American Thyroid Association, European Thyroid Association, and Endocrine Society Guidelines. Following the relevant established intervals would significantly impact timely diagnosis and therapy requirements for a substantial proportion of pregnant women.
Audiometric and Vestibular Function after Classic and Reverse Stapedotomy
Authors: Rebol Janez , Povalej Bržan Petra
Published: May 2024

Background and Objectives: Besides classical stapedotomy, reverse stapedotomy has been used for many years in the management of otosclerosis. Our study aims to investigate whether reversing the surgical steps in stapedotomy impacts vestibular function and hearing improvement. Materials and Methods: A cohort of 123 patients underwent either classic or reverse stapedotomy procedures utilizing a fiber–optic argon laser. Audiological assessments, following the guidelines of the Committee on Hearing and Equilibrium, were conducted, including pure tone average, air–bone (AB) gap, overclosure, and AB gap closure. Vestibular evaluation involved pre- and postoperative comparison of rotatory test parameters, including frequency, amplitude, and slow phase velocity of nystagmus. Results: The study demonstrated an overall median overclosure of 3.3 (3.3, 5.0) dB and a mean AB gap closure of 20.3 ± 8.8 dB. Postoperative median AB gap was 7.5 (7.5, 11.3) dB in the reverse stapedotomy group and 10.0 (10.0, 12.5) dB in the classic stapedotomy group. While overclosure and AB gap closure were marginally superior in the reverse stapedotomy group, these differences did not reach statistical significance. No significant disparities were observed in the frequency, slow phase velocity, or amplitude of nystagmus in the rotational test. Conclusions: Although not always possible, reverse stapedotomy proved to be a safe surgical technique regarding postoperative outcomes. Its adoption may mitigate risks associated with floating footplate, sensorineural hearing loss, and incus luxation/subluxation, while facilitating the learning curve for less experienced ear surgeons.
The Effect of “Proanthocyanidin” on Ischemia–Reperfusion Injury in Skeletal Muscles of Rats
Authors: Özer Abdullah , Koçak Başak , Sezen Şaban Cem , Arslan Mustafa , Kavutçu Mustafa
Published: May 2024

Background and Objectives: Lower limb skeletal muscle ischemia–reperfusion (IR) injury is associated with increased morbidity and mortality, and it is common in several clinical situations such as aortic aneurysms repairment, peripheral arterial surgery, vascular injury repairment, and shock. Although it is generally accepted that oxidative stress mediators have a significant role in IR injury, its precise mechanism is still unknown. Anecdotally, it is sustained not only by structural and functional changes in the organ it affects but also by damage to distant organs. The purpose of this report is to illustrate the effect of proanthocyanidin on IR injury. Materials and Methods: In our study, 18 male Wistar albino rats were used. The subjects were divided into three groups containing six mice each (control, C; ischemia–reperfusion, IR; ischemia–reperfusion and proanthocyanidin; IR-PRO). Intraperitoneal proanthocyanidin was given to the IR and proanthocyanidin groups 30 min before laparotomy, and 1 h ischemia led to these two groups. After one hour, reperfusion started. Muscle atrophy–hypertrophy, muscle degeneration–congestion, fragmentation–hyalinization, muscle oval-central nucleus ratio, leukocyte cell infiltration, catalase enzyme activity, and TBARS were all examined in lower-limb muscle samples after one hour of reperfusion. Results: When skeletal muscle samples were evaluated histopathologically, it was discovered that muscle atrophy–hypertrophy, muscle degeneration–congestion, fragmentation–hyalinization, and leukocyte cell infiltration with oval-central nucleus standardization were significantly higher in the IR group than in the C and IR-P groups. Oval-central nucleus standardization was significantly higher in the IR and IR-PRO groups than in the control group. TBARS levels were significantly higher in the IR group than in the control and IR-PRO groups, while catalase enzyme activity was found to be significantly lower in the IR group than in the control and IR-PRO groups. Conclusions: As a consequence of our research, we discovered that proanthocyanidins administered before IR have a protective impact on skeletal muscle in rats. Further research in this area is required.
Bariatric Surgery in Asthma: A Narrative Review
Authors: Mawlichanów Maciej , Tatara Paulina , Kwiatkowski Andrzej , Różańska-Walędziak Anna , Walędziak Maciej
Published: May 2024

Nearly 60% of asthmatics in the USA suffer from obesity. Asthma is a comorbid condition alongside obesity, commonly accompanied by conditions such as hypertension and type 2 diabetes. The positive effect of bariatric surgery on patients suffering from hypertension and type 2 diabetes, which leads to either a reduction in the dose of medication taken for the aforementioned diseases or the withdrawal of the disease, is quite well proven in the literature. Currently, the impact of bariatric operations on the control and course of bronchial asthma and pharmacological treatment has not been fully recognized and described, requiring further research; therefore, the following review of the literature was conducted.
HLA-DR and HLA-DQ Polymorphism Correlation with Sexually Transmitted Infection Caused by Chlamydia trachomatis
Authors: Pintea-Trifu Martina-Luciana , Vică Mihaela Laura , Bâlici Silvia-Ștefana , Leucuța Daniel-Corneliu , Coman Horia George , Nemeș Bogdan , Trifu Dragoș-Mihail , Siserman Costel-Vasile , Matei Horea-Vladi
Published: May 2024

Background and Objectives: Chlamydia trachomatis (C. trachomatis) represents one of the most prevalent bacterial sexually transmitted diseases. This study aims to explore the relationship between HLA alleles/genotypes/haplotypes and C. trachomatis infection to better understand high-risk individuals and potential complications. Materials and Methods: This prospective study recruited participants from Transylvania, Romania. Patients with positive NAAT tests for C. trachomatis from cervical/urethral secretion or urine were compared with controls regarding HLA-DR and -DQ alleles. DNA extraction for HLA typing was performed using venous blood samples. Results: Our analysis revealed that the presence of the DRB1*13 allele significantly heightened the likelihood of C. trachomatis infection (p = 0.017). Additionally, we observed that individuals carrying the DRB1*01/DRB1*13 and DQB1*03/DQB1*06 genotype had increased odds of C. trachomatis infection. Upon adjustment, the association between the DRB1*01/DRB1*13 genotype and C. trachomatis remained statistically significant. Conclusions: Our findings underscore the importance of specific HLA alleles and genotypes in influencing susceptibility to C. trachomatis infection. These results highlight the intricate relationship between host genetics and disease susceptibility, offering valuable insights for targeted prevention efforts and personalized healthcare strategies.
Can Storage Stability and Simulated Gastrointestinal Behavior Change the Cytotoxic Effects of Concentrated Guava Leaves Extract against Human Lung Cancer Cells?
Authors: Demaman Arend Giordana , Verruck Silvani , Zanchett Schneider Naira Fernanda , Oliveira Simões Cláudia Maria , Tres Marcus Vinícius , Prudêncio Elane Schwinden , Cunha Petrus José Carlos , Rezzadori Katia
Published: May 2024

The influence of storage stability and simulated gastrointestinal behavior of different extracts of guava leaves extracts (NC: not concentrated, and C10 and C20: concentrated by nanofiltration) was evaluated based on their total phenolic compound (TPC) contents and antioxidant activity as well as on their cytotoxic effects on A549 and Vero cells. The results showed that C10 and C20 presented high stability for 125 days probably due to their high TPC contents and antioxidant activity. The simulated gastrointestinal behavior modified their TPC contents; however, after all digestion steps, the TPC values were higher than 70%, which means that they were still available to exert their bioactivities. Additionally, the cytotoxic effects of these extracts were evaluated before and after the simulated gastrointestinal behavior or under different storage conditions. C10 presented the best selectivity indices (SI) values (IC50 Vero cells/IC50 A549 cells) at both conditions suggesting that it can be considered a potential extract to be developed as a functional food due to its resistance to the gastrointestinal digestion and storage conditions tested.
Microwave Treatment of Copper–Nickel Sulfide Ore for Promotion of Grinding and Flotation
Authors: Fang Xiaolei , Peng Zhiwei , Yin Tianle , Rao Mingjun , Li Guanghui
Published: May 2024

The effect of microwave treatment on the grinding and flotation performance of a typical copper–nickel sulfide ore was evaluated, based on the determination of its microwave absorption capability, grinding and flotation indexes such as crack percentage, mineral liberation degree, particle size distribution, relative work index (RWI), metal enrichment ratio and recovery. There were obvious differences between the microwave absorption capabilities of the main minerals in the ore, as demonstrated by their different microwave penetration depths. They also induced temperature differences between sulfide minerals and gangue minerals which could reach 418 °C after microwave treatment for 20 s. It was shown that microwave treatment could effectively improve the grindability of the ore, as proven by the increase in fine particles smaller than 0.074 mm and the decrease in RWI after grinding due to the higher crack percentage and mineral liberation degree. Moreover, microwave treatment affected the ore floatability because of the generation of cuprite, retgersite, and rozenite with poor floatability when the treatment time was extended. By microwave treatment for a proper time, 20 s, an optimal balance between the grindability and flotation performance could be achieved. Compared with the untreated ore, the RWI of the ore decreased by 11.5%. After flotation, the Cu and Ni enrichment ratios of the flotation concentrate increased by 0.3 and 0.2, respectively. Meanwhile, their corresponding recoveries increased by 4.2% and 3.1%. This study provides new insights for the treatment of copper–nickel sulfide ore to enhance the grinding and flotation process.
Comparison of Fluid Flow and Tracer Dispersion in Four-Strand Tundish under Fewer Strand Casting and Sudden Blockage of Strand Conditions
Authors: Song Jintao , Luo Yanzhao , Li Yuqian , Guo Zhijie , Wang Tianyang , Geng Mengjiao , Lin Wanming , Fan Jinping , Chen Chao
Published: May 2024

The study focuses on the four-strand tundish as the research object, aiming at the phenomenon of fewer strand casting (stable blockage) and sudden blockage of the tundish in industrial production. Numerical simulation methods are employed to compare the velocity vectors, flow fields, residence time distribution (RTD) curves, and outflow percentage curves under stable blockage and sudden blockage of the tundishes with a double-weir structure, U-shaped weir structure, and U-shaped weir structure with holes in the front. The results indicate that, after sudden blockage of the tundish strands, the flow field transitions from an unstable four-strand flow field to a stable three-strand flow field. Both the double-weir tundish and the U-shaped weir tundish reach a stable state after 200 s, while the U-shaped weir tundish with holes in the front reaches stability after 150 s. Additionally, compared to other structures, the tundish strands of the U-shaped weir with holes in the front are less affected by blockage, showing better consistency among strands and better adaptability under non-standard casting conditions.
Enhanced Hydrogen-Storage Properties of MgH2 Catalyzed via a Cerium Doped TiCrV BCC Alloy
Authors: Xiao Houqun , Zhang Xiaoxuan , Li Chenyu , Li Yuehai , Ma Chuanming , Wang Ruixiang , Yi Luocai , Chen Qingjun
Published: May 2024

In this work, Ce-doped Ti6Cr14V80 BCC hydrogen-storage alloys have been synthesized as catalysts to enhance the hydrogen-storage performance of MgH2 based on its room-temperature activation features and excellent durability. The Ti6Cr14V80Ce1 alloy was pre-ball milled under a hydrogen atmosphere into a Ti6Cr14V80Ce1Hx hydride. Different amounts of the Ti6Cr14V80Ce1Hx hydride were incorporated into MgH2 by ball milling to obtain the MgH2 + y wt%Ti6Cr14V80Ce1Hx (y = 0, 3, 5, 10, 15) nano-composites. With an optimization doping of 10 wt%Ti6Cr14V80Ce1Hx, the initial dehydrogenated temperature was decreased to 160 °C. Moreover, the composite can rapidly release 6.73 wt% H2 within 8 min at 230 °C. Also, it can absorb 2.0 wt% H2 within 1 h even at room temperature and uptake 4.86 wt% H2 within 10 s at 125 °C. In addition, the apparent dehydrogenated activation energy of the MgH2 + 10 wt%Ti6Cr14V80Ce1Hx composite was calculated to be 62.62 kJ mol−1 fitted by the JMAK model. The capacity retention was kept as 84% after 100 cycles at 300 °C. The ball milled Ti6Cr14V80Ce1Hx transformed from the initial FCC phase structure into a BCC phase after complete dehydrogenation and back into an FCC phase when fullly hydrogenated. A catalyst mechanism analysis revealed that the ‘autocatalytic effect’ originating in Ti6Cr14V80Ce1Hx plays a crucial role in boosting the de-/hydrogenation properties of MgH2. This work provides meaningful insights into rational designs of nano-compositing with different hydrogen-storage alloy catalyzed MgH2.
High Temperature Oxidation Behavior of High Al-Si Alloyed Vermicular Graphite Cast Iron for Internal Combustion Engine’s Hot-End Exhaust Components
Authors: Yilmaz Rifat , Bayata Fatma , Solak Nuri
Published: May 2024

This study investigated the influence of high silicon (4.2 wt%) and varying aluminum (3.5–4.8 wt%) content on the high temperature oxidation behavior and thermophysical properties of SiMoAl vermicular graphite cast iron for hot-end exhaust components. Isothermal oxidation tests at 800 °C and nonisothermal oxidation tests in a dry-air atmosphere were conducted on SiMo nodular iron, along with two SiMoAl vermicular graphite cast iron variants alloyed with 3.5 wt% Al and 4.8 wt% Al. The investigations revealed the formation of a thin duplex layer of oxide scale, consisting of an iron-rich external oxide layer and continuous aluminum oxide at the metal/oxide interface. Although aluminum oxide acted as a protective barrier by impeding the solid-state diffusion of oxygen, severe subsurface oxidation was observed due to the interconnected vermicular graphite covered by aluminum oxides after decarburization. Furthermore, based on nonisothermal oxidation experiments, the effective activation energy of oxidation was found to be significantly increased by the addition of aluminum, even though the oxidation activation energies of SiMoAl samples exhibited small changes in comparison to each other. Additionally, thermophysical analysis demonstrated a substantial decrease in the thermal conductivity and a slight increase in the thermal expansion with the addition of aluminum.
A Comprehensive Understanding of Thermal Barrier Coatings (TBCs): Applications, Materials, Coating Design and Failure Mechanisms
Authors: Bogdan Maria , Peter Ildiko
Published: May 2024

This review offers a comprehensive analysis of thermal barrier coatings (TBCs) applied to metallic materials. By reviewing the recent literature, this paper reports on a collection of technical information, involving the structure and role of TBCs, various materials and coating processes, as well as the mechanisms involved in the durability and failure of TBCs. Although TBCs have been successfully utilized in advanced applications for nearly five decades, they continue to be a subject of keen interest and ongoing study in the world of materials science, with overviews of the field’s evolution remaining ever relevant. Thus, this paper outlines the current requirements of the main application areas of TBCs (aerospace, power generation and the automotive and naval industries) and the properties and resistance to thermal, mechanical and chemical stress of the different types of materials used, such as zirconates, niobates, tantalates or mullite. Additionally, recent approaches in the literature, such as high-entropy coatings and multilayer coatings, are presented and discussed. By analyzing the failure processes of TBCs, issues related to delamination, spallation, erosion and oxidation are revealed. Integrating TBCs with the latest generations of superalloys, as well as examining heat transfer mechanisms, could represent key areas for in-depth study.
An Enhanced Approach for High-Strain Plasticity in Flat Anisotropic Specimens with Progressively Distorting Neck Sections
Authors: Mirone Giuseppe , Barbagallo Raffaele , Bua Giuseppe , Licignano Pietro , Tedesco Michele Maria
Published: May 2024

Characterizing the behavior of ductile metals at high strains is essential in various fields. In the case of thin sheets, rectangular cross-section specimens are used to characterize these materials, typically by tensile tests. Unlike cylindrical specimens, flat ones pose additional challenges for the hardening characterization at high strains, especially in the post-necking phase, which, for many high-strength steels, may cover most of the plastic strain range. After the onset of global necking, the rectangular cross-sections tend to distort with respect to their original shape, as their edges progressively curve and bulge inward. The localized necking occurring after the global one in thinner specimens, further distorts the necked zone. Additionally, sheet metals usually exhibit anisotropic characteristics that affect the derivation of the stress–strain curve and need to be dealt with. No exact method exists for the stress–strain characterization of ductile thin sheets at high strains from tensile tests. Although several approximate methods are available in the literature, they either discard the post-necking range or require highly advanced and complex experimental setups not suitable for industrial applications (e.g., 3D DIC). Then, this work proposes a relatively simple methodology for the experimental characterization of anisotropic thin sheet metals through tensile tests on rectangular cross-section specimens that delivers the true stress–strain curve of the material, extended over the necking range and up to fracture, accurately assessing the anisotropy and the distortion of the neck section. The proposed methodology, employing a standard single-camera experimental setup, is illustrated here, referring to four different steels for automotive applications with reference to a single material orientation; it is intended as representative of the repeated procedure involving tensile tests along 3 or more material directions in order to describe the whole anisotropic plastic response. A detailed comparison between the novel methodology and four other common approaches is carried out, highlighting the differences and the enhanced capabilities of the novel one proposed.
Overweight, Obesity, Hypertriglyceridemia, and Insulin Resistance Are Positively Associated with High Serum Copper Levels in Mexican Adults
Authors: Ramírez-Cruz Armando , Rios-Lugo María Judith , Soto-Sánchez Jacqueline , Juárez-Pérez Cuauhtémoc Arturo , Cabello-López Alejandro , Jiménez-Ramírez Carmina , Chang-Rueda Consuelo , Cruz Miguel , Hernández-Mendoza Héctor , Vazquez-Moreno Miguel
Published: May 2024

Recently, the role of trace elements in the pathophysiology of obesity, insulin resistance (IR), and metabolic diseases has been explored. In this cross-sectional study, we aimed to assess the association of overweight, obesity, and cardiometabolic traits with serum copper (Cu) levels in 346 Mexican adults. Serum Cu level was measured by inductively coupled plasma mass spectrometry (ICP-MS). Anthropometrical data were collected, and biochemical parameters were measured. The triglyceride-glucose (TyG) index was used as a surrogate marker to evaluate IR. Overweight and obesity status was positively associated with the serum Cu level (β = 19.434 ± 7.309, p = 0.008). Serum Cu level was observed to have a positive association with serum triglycerides level (β = 0.160 ± 0.045, p < 0.001) and TyG (β = 0.001 ± 0.001, p < 0.001). Additionally, high serum Cu level was positively associated with overweight and obesity status (odds ratio [OR] = 1.9, 95% confidence interval [95% CI] 1.1–3.4, p = 0.014), hypertriglyceridemia (OR = 3.0, 95% CI 1.7–5.3, p < 0.001), and IR (OR = 2.6, 95% CI 1.4–4.6, p = 0.001). In conclusion, our results suggest that overweight, obesity, hypertriglyceridemia, and IR are positively associated with serum Cu levels in Mexican adults.
A High-Energy, Wide-Spectrum, Spatiotemporal Mode-Locked Fiber Laser
Authors: Ge Boyuan , Lou Yajun , Guo Silin , Cai Yue , Zhang Xinhai
Published: May 2024

In this article, we demonstrate a high-energy, wide-spectrum, spatiotemporal mode-locked (STML) fiber laser. Unlike traditional single-mode fiber lasers, STML fiber lasers theoretically enable mode-locking with various combinations of transverse modes. The laser can deliver two different STML pulse sequences with different pulse widths, spectra and beam profiles, due to the different compositions of transverse modes in the output pulses. Moreover, we achieve a wide-spectrum pulsed output with a single-pulse energy of up to 116 nJ, by weakening the spectral filtering and utilizing self-cleaning. Strong spatial and spectral filtering are usually thought to be necessary for achieving STML. Our experiment verifies the necessity of spatial filtering for achieving STML, and we show that weakening unnecessary spectral filtering provides an effective way to increase the pulse energy and spectrum width of mode-locked fiber lasers.
Miniaturized and High Volumetric Energy Density Power Supply Device Based on a Broad-Frequency Vibration Driven Triboelectric Nanogenerator
Authors: Wu Liting , Ren Zewei , Wang Yanjun , Tang Yumin , Wang Zhong Lin , Yang Rusen
Published: May 2024

The widespread vibration is one of the most promising energy sources for IoT and small sensors, and broad-frequency vibration energy harvesting is important. Triboelectric nanogenerators (TENGs) can convert vibration energy into electrical energy through triboelectricity and electrostatic induction, providing an effective solution to the collection of broad-frequency vibration energy. Also, the power supply in constrained and compact spaces has been a long-standing challenge. Here, a miniaturized power supply (MPS) based on a broad-frequency vibration-driven triboelectric nanogenerator (TENG) is developed. The size of the MPS is 38 mm × 26 mm × 20 mm, which can adapt to most space-limited environments. The TENG device is optimized through theoretical mechanical modeling for the external stimuli, it can efficiently harvest vibrational energy in the frequency range of 1–100 Hz and has a high output power density of 134.11 W/cm3. The developed device demonstrates its practical application potential in powering small electronics like LEDs, watches, and timers.
Twinning Impact on the Structure and Hypotheses on the Growth Mechanism of Kermesite: Insights from Yunnan, China
Authors: Yu Hong , Wang Denghong , Zhu Zeying , Li Wenyuan , Wang Dong , Chen Zhenyu , Li Yike , Ke Changhui
Published: May 2024

Kermesite (Sb2S2O), a needle-like unstable secondary oxysulfide, has made visible advancements in optimizing its triclinic crystal system through twinning discovery. However, research on twinning behavior at micro and nano scales, including its growth mechanisms and impact on kermesite morphologies, remains notably scarce. Our study focuses on kermesite crystal clusters from a private collection in Yunnan, China, confirming the chemical formula as Sb2S1.97O1.03 through EPMA. Single-crystal XRD yielded refined unit cell parameters (a = 8.153(5) Å, b = 10.717(7) Å, c = 5.796(3) Å; α = 102.836(10)°, β = 110.556(8)°, γ = 100.999(12)°), revealing space group P1¯ with Z = 4 and indicating twinning with a ratio of 27.4%. Remarkably, a Transmission Electron Microscope (TEM) provided the first direct observation of twinning in natural kermesite, revealing rotational twins with varying widths and lengths (ranging from 100 nm to several millimeters). Analysis and simulation elucidated that rotational twins, generated by a 180° rotation, align with the mineral’s elongation direction along the [Sb2S2O4]n chains (a-axis), challenging the conventional long-axis direction (b-axis) for crystal growth. This study proposes a symbiotic relationship between kermesite growth and twinning, suggesting that the observed X-shaped growth in crystal clusters results from the collaboration of single crystals (growing along b) and twins (growing along a) in the unit cell. These findings contribute to our understanding of kermesite’s structural complexities and the potential growth and formation mechanism of crystal clusters.
Use of Natural Zeolite Clinoptilolite in the Preparation of Photocatalysts and Its Role in Photocatalytic Activity
Authors: Pavlović Jelena , Rajić Nevenka
Published: May 2024

The use of natural zeolite clinoptilolite in preparing photocatalysts and its function in photocatalysis are discussed in this review. The importance of advanced oxidation processes (AOPs) and the potential of heterogeneous photocatalysis in removing environmental pollutants are emphasized. The review focuses on the synergistic effects of clinoptilolite with semiconductors (TiO2, ZnO, CuO, SnO2, and NiO) to prepare stable and active photocatalysts, highlighting recent advancements in this field. It explores clinoptilolite’s structural characteristics, highlighting its microporous nature, adaptable framework, and improved textural properties due to acid and alkali treatments. Particle size, crystal phase, and calcination temperature are three key synthesis parameters that affect photocatalytic activity and are highlighted in the discussion of these parameters and their methods. A discussion is held regarding the processes and mechanisms of photocatalytic degradation of different organic compounds under varying irradiation conditions, including UV, visible, and ambient sunlight. Clinoptilolite is vital in improving supported semiconductor oxides’ photocatalytic efficiencies, which aid in pollutant degradation and environmental remediation.
Significance of Sonic Velocities in Limestones and Dolostones: A Comprehensive Study Revealing Limited Impact of Mineralogy
Authors: Weger Ralf J. , Baechle Gregor T. , Shen Shouwen , Eberli Gregor P.
Published: May 2024

Seismic reflection data and implicitly sonic velocity are undoubtedly the most important source of information for large-scale subsurface characterization. Yet, deriving reservoir and fluid flow properties from acoustic data is still challenging in carbonates, which display large acoustic velocity variations that contest many of the conventional assumptions regarding wave propagation in porous media. In this comprehensive study on 370 carbonate samples (247 limestones and 123 dolomites), we re-evaluate the impact of mineral velocity on bulk rock acoustic properties of dolomite and limestone by assessing the link between sonic velocity and the rock’s pore geometry. We quantify pore size and pore network complexity using parameters from both digital image analysis (DIA) and the extended Biot theory (EBT). We then compare DIA and EBT parameters to assess the impact of pore network geometry versus mineral velocity on the acoustic velocity of carbonate rocks. We explore the usefulness of EBT parameter γk in improving permeability estimates. Published values of velocity indicate that dolomites exhibit higher velocities than limestones at any given porosity. Our laboratory measurements of acoustic velocity, however, reveal that both dolomites and limestones show extreme variations in sonic velocities where samples with compressional velocity of ~5000 m/s may range in porosity from 5% to 25% and samples with porosity of ~20% may range in velocity from ~4000 m/s to 5700 m/s. Through the quantitative assessment of the pore network in our samples we document that pore network geometry has much more impact on the acoustic velocity of carbonates than variations in mineralogy, in this case dolomite and calcite. Most of the dolostone samples studied are dominated by small pores, resulting in relatively low velocities for their given porosity, while limestones with similar velocity–porosity values often possess simpler pore networks with larger pores. This pore size difference offsets the faster velocity of dolomite. The extended Biot theory parameter γk, captures this variation in pore size and internal geometry and exhibits a strong correlation to specific surface. Moreover, γk captures the impact of internal pore geometry on acoustic velocity, providing the basis for challenging existing assumptions regarding the importance of mineral velocity. By quantifying internal geometry, γk can improve permeability estimates in reservoir characterization and enhance evaluations of producibility and injectability. With that, it has direct implications on general geophysics, hydrocarbon exploration, and CCS initiatives.
Comparison of the Application of High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) and Collision/Reaction Cell Technology of Inductively Coupled Plasma Mass Spectrometry (ICP-CCT-MS) in the Determination of Selenium in Coal-Bearing Strata
Authors: Zhao Shumao , Jia Rongkun , Han Qiuchan , Shang Niande , Teng Kaiyan , Feng Jiawei
Published: May 2024

Selenium, a trace element of significant importance for human health and the environment, can be introduced into the environment through coal combustion. Accurate determination of selenium in coal and coal-bearing strata is essential for implementing effective management strategies and control measures to minimize potential risks to human health and the environment. This study introduces an improved approach for the determination of 77Se in the medium resolution mode using HR-ICP-MS, effectively separating interference from doubly charged ions and enabling precise determination of selenium in coal-bearing strata. The relative errors of the standard reference samples obtained by HR-ICP-MS are between 0.65% and 6.33%, comparing to that of ICP-CCT-MS (1.58%–17.27%), prove the reliability of this method. Additionally, the X (bar)—S control charts obtained from HR-ICP-MS compared to ICP-CCT-MS demonstrate the superior stability of HR-ICP-MS in continuous determination. Consequently, though ICP-CCT-MS has better instrumental stability reflected through the internal standard recovery (ICP-CCT-MS:104.81%; HR-ICP-MS:80.54%), HR-ICP-MS is recommended as the preferred method for selenium determination in coal-bearing strata because of its high accuracy and good stability.
Investigations of Antioxidant and Anti-Cancer Activities of 5-Aminopyrazole Derivatives
Authors: Rapetti Federica , Spallarossa Andrea , Russo Eleonora , Caviglia Debora , Villa Carla , Tasso Bruno , Signorello Maria Grazia , Rosano Camillo , Iervasi Erika , Ponassi Marco , Brullo Chiara
Published: May 2024

To further extend the structure-activity relationships (SARs) of 5-aminopyrazoles (5APs) and identify novel compounds able to interfere with inflammation, oxidative stress, and tumorigenesis, 5APs 1–4 have been designed and prepared. Some chemical modifications have been inserted on cathecol function or in aminopyrazole central core; in detail: (i) smaller, bigger, and more lipophilic substituents were introduced in meta and para positions of catechol portion (5APs 1); (ii) a methyl group was inserted on C3 of the pyrazole scaffold (5APs 2); (iii) a more flexible alkyl chain was inserted on N1 position (5APs 3); (iv) the acylhydrazonic linker was moved from position 4 to position 3 of the pyrazole scaffold (5APs 4). All new derivatives 1–4 have been tested for radical scavenging (DPPH assay), anti-aggregating/antioxidant (in human platelets) and cell growth inhibitory activity (MTT assay) properties. In addition, in silico pharmacokinetics, drug-likeness properties, and toxicity have been calculated. 5APs 1 emerged to be promising anti-proliferative agents, able to suppress the growth of specific cancer cell lines. Furthermore, derivatives 3 remarkably inhibited ROS production in platelets and 5APs 4 showed interesting in vitro radical scavenging properties. Overall, the collected results further confirm the pharmaceutical potentials of this class of compounds and support future studies for the development of novel anti-proliferative and antioxidant agents.
Immersive Virtual Colonography Viewer for Colon Growths Diagnosis: Design and Think-Aloud Study
Authors: Serras João , Duchowski Andrew , Nobre Isabel , Moreira Catarina , Maciel Anderson , Jorge Joaquim
Published: May 2024

Desktop-based virtual colonoscopy is a proven and accurate process for identifying colon abnormalities. However, it is time-consuming. Faster, immersive interfaces for virtual colonoscopy are still incipient and need to be better understood. This article introduces a novel design that leverages VR paradigm components to enhance the efficiency and effectiveness of immersive analysis. Our approach contributes a novel tool highlighting unseen areas within the colon via eye-tracking, a flexible navigation approach, and a distinct interface for displaying scans blended with the reconstructed colon surface. The path to evaluating and validating such a tool for clinical settings is arduous. This article contributes a formative evaluation using think-aloud sessions with radiology experts and students. Questions related to colon coverage, diagnostic accuracy, and time to complete are analyzed with different user profiles. Although not aimed at quantitatively measuring performance, the experiment provides lessons learned to guide other researchers in the field.
Prevalence and Antibiotic Resistance Profile of Clostridium perfringens Isolated from Pork and Chicken Meat in Vietnam
Authors: Duc Hoang Minh , Hoa Tran Thi Khanh , Ha Cam Thi Thu , Van Hung Le , Van Thang Nguyen , Minh Son Hoang , Flory Gary A.
Published: May 2024

Clostridium perfringens is one of the most important zoonotic pathogens as it can cause food poisoning in humans and necrotic enteritis in both animals and humans. Meat, especially pork and chicken meat, is considered the main vehicle for the transmission of C. perfringens from animals to humans. The purpose of this study was to determine the prevalence, toxinotype, and antimicrobial resistance profile of C. perfringens isolated from pork and chicken meat sold in Vietnam. The isolation results showed that 15/50 (30%) of pork samples and 8/50 (16%) of chicken meat samples were contaminated with C. perfringens. The isolates exhibited their highest resistance rate to tetracycline (21/23; 91.30%) and clindamycin (10/23; 43.48%). On the contrary, their lowest resistance rates were observed in response to imipenem (2/23; 8.70%) and cefoxitin (1/23; 4.35%). In particular, 34.78% (8/23) of C. perfringens isolates were identified to be multidrug-resistant strains. The results of toxin genotyping indicated that all isolates were positive for the cpa gene and belonged to type A.