-
Materials (Basel, Switzerland) Jun 2024The article discusses the phenomena and destructive mechanisms occurring on the surface of 1.2344 steel dies used during the hot forging of disc-type forgings....
Increasing the Working Time of Forging Tools Used in the Industrial Process of Producing a Disk-Type Forging Assigned for a Gearbox through the Application of Hybrid Layers.
The article discusses the phenomena and destructive mechanisms occurring on the surface of 1.2344 steel dies used during the hot forging of disc-type forgings. Preliminary research has shown that gas nitriding alone, used so far, is insufficient due to the occurrence of destructive mechanisms other than abrasive wear, such as thermal and thermomechanical fatigue, which cause the average durability of such tools to be approximately 5000 forgings. Analyses were also carried out to assess the load on forging tools using numerical modeling (Forge 3.0NxT), which confirmed the occurrence of large and cyclically changing thermal and mechanical loads during the forging process. Therefore, in order to increase operational durability, it was decided to use two types of hybrid layers, differing in the PVD coating used: TiCrAlN and CrN, and then subjected to gas nitriding (GN). The obtained results showed that, depending on the area of the tool and the current working conditions, the applied PVD coatings protect the surface layer of the tool against the dominant destructive mechanisms. In both cases, the strength increased to the level of 7000 forgings, the tools could continue to work, and globally, slightly better results were obtained for the GN+TiCrAlN layer. The CrN-type layer protects the tool more against thermal fatigue, while the TiCrAlN layer is more resistant to abrasive wear. In areas where the hybrid layer was worn, a decrease in hardness was observed from 1300 HV to 600-700 HV, and in places of intense material flow (front-point 2 and tool bridge-point 9) the hardness dropped to below 400 HV, which may indicate local tempering of the material. Moreover, the research has shown that each process and tool should be analyzed individually, and the areas in the tool where particular destructive mechanisms dominate should be identified, so as to further protect the forging tool by using appropriate protective coatings in these areas.
PubMed: 38930374
DOI: 10.3390/ma17123005 -
Materials (Basel, Switzerland) Jun 2024In this study, the ball-on-disk sliding wear and tribocorrosion behavior in the HSO and HCl solution of NiCoCrMoCu alloys with carbon additions of 0.2, 1, 1.5, and 2...
In this study, the ball-on-disk sliding wear and tribocorrosion behavior in the HSO and HCl solution of NiCoCrMoCu alloys with carbon additions of 0.2, 1, 1.5, and 2 wt.% with the AlO ball as a counterpart was investigated systematically. Obvious tribocorrosion antagonistic effects were found after wear in both aqueous solutions. Compared with dry sliding wear conditions, the lubrication effect of the aqueous solution significantly reduces the wear rate of the alloy, and the reduction effect in the HSO aqueous solution was more obvious than that in HCl. The antagonistic effects of the 0.2C and 1C alloys decrease with the load and sliding rate, while those of the 1.5C and 2C alloys increase. The (coefficient of friction) COF and wear rate under different loads and sliding rates were analyzed using the response surface analysis (RSM) method. It was found that the COF mainly showed dependence on the sliding rate, while the wear rate showed dependence on load and sliding speed.
PubMed: 38930340
DOI: 10.3390/ma17122971 -
Journal of Clinical Medicine Jun 2024: Lumbar disc herniation, a complex challenge in spinal health, significantly impacts individuals across diverse age groups. This article delves into the intricacies of...
: Lumbar disc herniation, a complex challenge in spinal health, significantly impacts individuals across diverse age groups. This article delves into the intricacies of this condition, emphasising the pivotal role of anatomical considerations in its understanding and management. Additionally, lumbar discectomy might be considered an "easy" surgery; nevertheless, it carries significant risks. The aim of the study was to present a groundbreaking "three-step approach" with some anatomical insight derived from our comprehensive clinical experiences, designed to systematise the surgical approach and optimise the outcomes, especially for young spine surgeons. We highlighted the purpose of the study and introduced our research question(s) and the context surrounding them. : This retrospective study involved patients treated for lumbar disc herniation at a single institution. The patient demographics, surgical details, and postoperative assessments were meticulously recorded. All surgeries were performed by a consistent surgical team. : A total of 847 patients of the 998 patients initially included completed the follow-up period. A three-step approach was performed for every patient. The recurrence rate was 1.89%. Furthermore, the incidence of lumbar instability and the need for reoperation were carefully examined, presenting a holistic view of the outcomes. : The three-step approach emerged as a robust and effective strategy for addressing lumbar disc herniation. This structured approach ensures a safe and educational experience for young spinal surgeons.
PubMed: 38930100
DOI: 10.3390/jcm13123571 -
Journal of Clinical Medicine Jun 2024: Standard oblique cages cannot cover endplates side-to-side, which is an important biomechanical factor for reducing the risk of cage subsidence and for restoring...
New Axially Expandable Oblique Cage Designed for Anterior to Psoas (ATP) Approach: Indications-Surgical Technique and Clinical-Radiological Outcomes in Patients with Symptomatic Degenerative Disc Disease.
: Standard oblique cages cannot cover endplates side-to-side, which is an important biomechanical factor for reducing the risk of cage subsidence and for restoring correct segmental lordosis. The aim of this study is to evaluate the radiological and clinical results of a new oblique lumbar interbody fusion (OLIF) axially expandable cage. : This is a prospective observational case-control study. From March 2018 to June 2020, 28 consecutive patients with lumbar degenerative disease underwent an ATP approach, with the insertion of a new axially expandable cage, which was used as a stand-alone procedure or followed by posterior percutaneous pedicle fixation. : Twenty-eight patients in both groups met the inclusion criteria. The mean follow-up time was 31.2 months (range of 13-37). The clinical results were not significantly different, although in the control group, two major intraoperative complications were recorded, and slight improvements in ODI and SF-36 scores were observed in the study group. The radiological results showed a less frequent incidence of subsidence and a higher rate of fusion in the study group compared to controls. : The axially expandable oblique cage for lumbar inter body fusion, specifically designed for the ATP approach, represents an innovation and a technical improvement. The insertion and the axial expansion technique are safe and easy. The large footprint could obtain solid and effective arthrodesis, potentially reducing the risk of subsidence.
PubMed: 38929973
DOI: 10.3390/jcm13123444 -
Antibiotics (Basel, Switzerland) Jun 2024With the increasing burden of carbapenem-resistant (CR-Kp), including high rates of healthcare-associated infections, treatment failure, and mortality, a good...
UNLABELLED
With the increasing burden of carbapenem-resistant (CR-Kp), including high rates of healthcare-associated infections, treatment failure, and mortality, a good therapeutic strategy for attacking this multi-resistant pathogen is one of the main goals in current medical practice and necessitates the use of novel antibiotics or new drug combinations.
OBJECTIVES
We reviewed the clinical and microbiological outcomes of seven patients treated at the "Agrippa Ionescu" Clinical Emergency Hospital between October 2023 and January 2024, aiming to demonstrate the synergistic activity of the ceftazidime-avibactam (C/A) plus aztreonam (ATM) combination against the co-producers of NDM + OXA-48-like CR-Kp.
MATERIAL AND METHODS
Seven CR-Kp with NDM and OXA-48 as resistance mechanisms were tested. Seven patients treated with C/A + ATM were included. The synergistic activity of C/A + ATM was proven through double-disk diffusion in all seven isolates. Resistance mechanisms like KPC, VIM, OXA-48, NDM, IMP, and CTX-M were assessed through immunochromatography.
RESULTS
With a mean of nine days of treatment with the synergistic combination C/A + ATM, all patients achieved clinical recovery, and five achieved microbiological recovery.
CONCLUSIONS
With the emerging co-occurrence of OXA-48 and NDM among in Romania, the combination of C/A and ATM could be a promising therapeutic option.
PubMed: 38927216
DOI: 10.3390/antibiotics13060550 -
Antibiotics (Basel, Switzerland) Jun 2024Dental caries is a global health problem that requires better prevention measures. One of the goals is to reduce the prevalence of the cariogenic Gram-positive bacterium...
Dental caries is a global health problem that requires better prevention measures. One of the goals is to reduce the prevalence of the cariogenic Gram-positive bacterium . We have recently shown that naturally occurring arachidonic acid (AA) has both anti-bacterial and anti-biofilm activities against this bacterium. An important question is how these activities are affected by other anti-bacterial compounds commonly used in mouthwashes. Here, we studied the combined treatment of AA with chlorhexidine (CHX), cetylpyridinium chloride (CPC), triclosan, and fluoride. Checkerboard microtiter assays were performed to determine the effects on bacterial growth and viability. Biofilms were quantified using the MTT metabolic assay, crystal violet (CV) staining, and live/dead staining with SYTO 9/propidium iodide (PI) visualized by spinning disk confocal microscopy (SDCM). The bacterial morphology and the topography of the biofilms were visualized by high-resolution scanning electron microscopy (HR-SEM). The effect of selected drug combinations on cell viability and membrane potential was investigated by flow cytometry using SYTO 9/PI staining and the potentiometric dye DiOC2(3), respectively. We found that CHX and CPC had an antagonistic effect on AA at certain concentrations, while an additive effect was observed with triclosan and fluoride. This prompted us to investigate the triple treatment of AA, triclosan, and fluoride, which was more effective than either compound alone or the double treatment. We observed an increase in the percentage of PI-positive bacteria, indicating increased bacterial cell death. Only AA caused significant membrane hyperpolarization, which was not significantly enhanced by either triclosan or fluoride. In conclusion, our data suggest that AA can be used together with triclosan and fluoride to improve the efficacy of oral health care.
PubMed: 38927206
DOI: 10.3390/antibiotics13060540 -
Science Advances Jun 2024Mechanical computing encodes information in deformed states of mechanical systems, such as multistable structures. However, achieving stable mechanical memory in most...
Mechanical computing encodes information in deformed states of mechanical systems, such as multistable structures. However, achieving stable mechanical memory in most multistable systems remains challenging and often limited to binary information. Here, we report leveraging coupling kinematic bifurcation in rigid cube-based mechanisms with elasticity to create transformable, multistable mechanical computing metastructures with stable, high-density mechanical memory. Simply stretching the planar metastructure forms a multistable corrugated platform. It allows for independent mechanical or magnetic actuation of individual bistable element, serving as pop-up voxels for display or binary units for various tasks such as information writing, erasing, reading, encryption, and mechanologic computing. Releasing the pre-stretched strain stabilizes the prescribed information, resistant to external mechanical or magnetic perturbations, whereas re-stretching enables editable mechanical memory, akin to selective zones or disk formatting for information erasure and rewriting. Moreover, the platform can be reprogrammed and transformed into a multilayer configuration to achieve high-density memory.
PubMed: 38924402
DOI: 10.1126/sciadv.ado6476 -
Veterinary Medicine and Science Jul 2024Although salmonellosis is considered to be a foodborne zoonotic disease, pets can play a significant role in the dissemination of antimicrobial-resistant Salmonella...
BACKGROUND
Although salmonellosis is considered to be a foodborne zoonotic disease, pets can play a significant role in the dissemination of antimicrobial-resistant Salmonella organisms to humans because of close contact with their owners.
OBJECTIVES
To determine the prevalence, risk factors, virulence factors, serotypes, and antimicrobial resistance profile of Salmonella in pet dogs and cats in Turkey and to assess the public health risk. Furthermore, to perform macroscopic comparison of lactic acid bacteria (LAB) in Salmonella-positive and Salmonella-negative animals.
METHODS
International Standards Organization (ISO) 6579-1:2017 and Food and Drug Administration (FDA) methods were used to compare the effectiveness of culture methods in the identification of Salmonella in 348 rectal swabs. Positive isolates were serotyped using the slide agglutination method according to the White-Kauffmann-Le Minor scheme and the presence of virulence genes (invA and stn) were evaluated by polymerase chain reaction (PCR). Antimicrobial activity was tested by Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines.
RESULTS
Salmonella prevalence was 5.73% (9/157) in dogs and 0.0% (0/191) in cats. Eight (8/9) isolates were cultured with the ISO method and 5 (5/9) isolates were cultured with the FDA method. Macroscopic results revealed that Salmonella agents had no effect on LAB. Three different serotypes were detected and all isolates were positive for virulence genes. Antibiotic resistance profiling indicated that 11.1% of the isolates were MDR and the highest resistance was found for ciprofloxacin. MDR-resistant S. Virchow and carbapenem-resistant S. Enteritidis were detected from dog isolates. There was a significant difference between raw meat consumption and Salmonella carriage (p < 0.01).
CONCLUSIONS
Dogs could be potential carriers of Salmonella infection. The isolation of Salmonella in healthy dogs instead of dogs suffering from diarrhoea indicates that attention should be paid to asymptomatic carriage. The emergence of resistance among zoonotic Salmonella isolates poses a significant threat to public health.
Topics: Salmonella; Dog Diseases; Salmonella Infections, Animal; Turkey; Cat Diseases; Pets; Prevalence; Serogroup; Rectum; Virulence Factors; Risk Factors; Risk Assessment; Anti-Bacterial Agents; Drug Resistance, Bacterial; Lactobacillales; Animals; Cats; Dogs
PubMed: 38924270
DOI: 10.1002/vms3.1513 -
Pathogens (Basel, Switzerland) May 2024The occurrence of antibiotic-resistant bacteria in foodstuff involves a human health risk. Edible insects are a precious resource; however, their consumption raises food...
The occurrence of antibiotic-resistant bacteria in foodstuff involves a human health risk. Edible insects are a precious resource; however, their consumption raises food safety issues. In this study, the occurrence of antibiotic resistant bacteria in laboratory-reared fresh mealworm larvae ( L.) and frass was assessed. Antibiotics were not used during the rearing. and enterococci were isolated from 17 larvae and eight frass samples. In total, 62 and 69 isolates presumed to belong to and spp., respectively, were obtained and tested for antibiotic susceptibility via disk diffusion. Based on the results, isolates were grouped, and representative resistant isolates were identified at species level through gene sequencing. For enterococci resistance, percentages higher than 15% were observed for vancomycin and quinupristin-dalfopristin, whereas resistance higher than 25% was found against cefoxitin, ampicillin, and amoxicillin-clavulanic acid. Based on the species identification, the observed resistances seemed to be intrinsic both for enterococci and , except for some β-lactams resistance in (cefoxitin and aztreonam). These could be due to transferable genetic elements. This study suggests the need for further investigations to clarify the role of edible insects in the spreading of antibiotic resistance determinants through the food chain.
PubMed: 38921754
DOI: 10.3390/pathogens13060456 -
Insects Jun 2024The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is...
The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for the cultivation of the darkling beetle (Fabricius, 1775) (Coleoptera: Tenebrionidae) in laboratory conditions as a model object for studying the biology of saproxylophagous beetles. To assess the influence of the diet, a number of physiological parameters were measured, including development time, body size, and weight of all stages of the beetle's life cycle, as well as its immune status. The immune status of was assessed on the basis of larval hemolymph antibacterial activity against six different bacterial strains assessed using disk-diffusion and photometric tests. Our findings show that the FD reduces development time and boosts the immune status as compared to beetles reared on a standard diet (SD). Samples from FD-reared larvae had pronounced antibacterial activity as compared to samples from SD-reared larvae. This work is of fundamental importance for understanding the correlations between nutrition and development of saproxylic Coleoptera and is the first report on immune status regulation in this group of insects.
PubMed: 38921150
DOI: 10.3390/insects15060435