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1.
Sci Rep ; 14(1): 19827, 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39191868

RESUMEN

Problems associated with dissimilar fusion welding are mainly originated from the differences in melting points, coefficients of thermal conductivity and thermal expansion, …etc., and carbon content when welding dissimilar ferrous materials. In this study, the problems associated with dissimilar fusion welding of stainless steel AISI304 with ductile cast iron DCI grade A536 were investigated. Using shielded metal arc welding (SMAW) process, various welding parameters were studied to investigate the successful/accepted dissimilar welded joint(s). Welding electrodes and welding techniques were the main studied parameters. Microstructural and mechanical investigations were carried out for welded joints under different welding parameters. Tensile, impact and hardness tests coupled with optical and scanning electron microscopic examinations with EDX analysis were made for metallurgical and mechanical evaluations of welded joints. This extensive study could solve the problem of dissimilar welding between ductile cast iron and 304 stainless steel. The main results showed that joints welded by ENiCrFe-3 electrode in root pass and ENiFe-CI in filling passes were the successful dissimilar welded joints with 422 MPa tensile strength which represents 104% of annealed DCI base metal and without any changes in toughness properties, where toughness at HAZ of DCI was 18 J. High Ni content in weld metal increased the strength, ductility and reduced the weld metal dilution.

2.
Ultrastruct Pathol ; : 1-16, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39166773

RESUMEN

Renal disease is a common cause of morbidity and mortality in patients with plasma cell dyscrasias. The serum-free light chain assay is used in patients, mostly older, with unexplained acute kidney injury to screen for potential myeloma cast nephropathy. This study consists of a systematic review of diagnostic features in myeloma cast nephropathy. The morphological features of tubular casts in patients with multiple myeloma have not been systematically analyzed. This study focuses on the morphology of these casts, emphasizing ultrastructural features, in a series of 23 patients with light chain ("myeloma") cast nephropathy and compared them with casts in 10 patients with various diseases. The immunofluorescence data were correlated with morphological findings to provide diagnostic assessments and practice guidelines. The ultrastructural features identified as diagnostic of casts associated with myeloma included: amyloid and crystals in the casts, multiple well-defined fracture planes forming a complex jigsaw puzzle arrangement of cast contents, indicative of the fragility of the immunoglobulin light chains involved, and reactive tubular cells lining the tubules with the casts. These features were seen in 95.2% of MCN cases and none of the casts in other renal conditions. Myeloma casts exhibited light chain monoclonality in a significant percentage of the MCN cases and often no staining for IgA or IgM. In contrast, the majority of non-myeloma casts stained for both kappa and lambda light chains, lgA, and lgM, and showed ultrastructurally a rather uniform finely to coarsely granular electron density occasionally admixed with cellular debris.

3.
Data Brief ; 55: 110723, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39156666

RESUMEN

The underwater environment is characterized by complex light traversal, encompassing effects such as color loss, contrast loss, water distortion, backscatter, light attenuation, and color cast, which vary depending on water purity, depth, and other factors. The dataset presented in this paper is prepared with 100 ground-truth images and 1,50,000 synthetic underwater images. This dataset approximates the effects of underwater environment with implementable combinations of color cast, blurring, low-light, and contrast reduction. These effects and their combinations, with different severity levels are applied to each ground-truth image to generate as many as 150 synthetic underwater images. In addition to the dataset of 1,50,100 images, a comprehensive set of 21 focus metrics, including the average contrast measure operator, Brenner's gradient-based metric, and many others, are calculated for each image.

4.
Environ Monit Assess ; 196(9): 787, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39103555

RESUMEN

Noise pollution is an unintentional consequence of mining activities, needing rigorous assessment, monitoring, and mitigation techniques to reduce its impact on local residents and ecosystems. The study specifically examines the noise pollution from rare earth mining activities in the Neendakara-Kayamkulam (NK) coastal belt, Kollam, Kerala, India, a region rich in ilmenite, rutile, sillimanite, zircon, and monazite. Despite the known environmental and health impacts of noise pollution, there is limited specific data on its magnitude and sources in this region, as well as a lack of effective mitigation strategies tailored to rare earth mining operations. Studies have indicated that mining operations, such as the movement of heavy mineral sands, considerably elevate noise levels, which have an effect on the environment's quality and public health. This study seeks to fill the gap by geospatial mapping and assessing the noise levels and recommend measures to effectively mitigate noise pollution. Systematic noise measurements were conducted at 48 suitable locations within the NK coastal belt, including residential, commercial, industrial, coastal, and silence zones. The noise levels vary from 49.1 dB(A) near a religious place to 82.4 dB(A) near the local industry. The study employs geospatial noise mapping and land cover superimposition to implement class-specific mitigation measures for noise pollution in a coastal vicinity mixed land use area, including natural and vegetative barriers, operational scheduling, zoning, and land use planning.


Asunto(s)
Monitoreo del Ambiente , Minería , Ruido , India , Monitoreo del Ambiente/métodos , Metales de Tierras Raras/análisis , Contaminación Ambiental/estadística & datos numéricos
5.
Front Surg ; 11: 1404746, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39086923

RESUMEN

Introduction: Ankle fractures require temporary fixation to allow swelling to subside prior to surgery; this is typically achieved using calcaneal distraction or cast immobilization. We compared the results of these methods in the treatment of Danis-Weber type C ankle fractures. Methods: This retrospective study analyzed the data of 86 patients with Danis-Weber type C ankle fractures, of whom 40 underwent calcaneal distraction and 46 underwent cast immobilization. Clinical measures including preoperative detumescence time, daily swelling value, skin condition, and pain, SF-36 Health Survey (SF-36) score and ankle scores were compared between the two groups. Results: Baseline characteristics did not differ significantly between the groups. Calcaneal distraction resulted in a lower preoperative detumescence time (6.22 ± 0.64 vs. 8.94 ± 0.82 days) and lower daily swelling values compared with cast immobilization, leading to a lower skin necrosis rate. Resting pain scores were significantly lower in the calcaneal distraction group than in the cast immobilization group at various postoperative time points (P < 0.05). Ankle function scores were higher in the calcaneal distraction group than in the cast immobilization group at 12 months postoperatively (P < 0.05), indicating improved outcomes. Additionally, the SF-36 quality of life scores of patients undergoing calcaneal distraction were notably superior to those in the cast immobilization group. Discussion: Calcaneal distraction is superior to cast immobilization in reducing soft tissue swelling, alleviating pain, and enhancing ankle function recovery in patients with Danis-Weber type C ankle fractures. Early calcaneal distraction upon hospital admission is recommended to optimize surgical outcomes.

6.
Cureus ; 16(7): e63572, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39087162

RESUMEN

Superior mesenteric artery (SMA) syndrome is a rare disease in which the third part of the duodenum between the SMA and the abdominal aorta is compressed, leading to small bowel obstruction. Treatment is usually conservative, such as parenteral and nasojejunal nutrition. The pathophysiology includes loss of the retroperitoneal fat layer and subsequent duodenal compression. We present a 53-year-old malnourished female patient who came with complaints of vomiting, constipation, abdominal pain, and distension for four days. This article highlights the diagnostic challenges associated with SMA syndrome and emphasizes the importance of early diagnosis and intervention.

7.
J Phys Ther Sci ; 36(8): 430-434, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39092413

RESUMEN

[Purpose] When fabricating metal strut ankle-foot orthoses, previous studies have reported that shape acquisition is more efficient with a plastic cast than with a plaster of Paris bandage; however, this has not been quantitatively evaluated. This study aimed to clarify the usefulness of plastic casts by quantitatively evaluating the time spent and body shape accuracy among different methods of shape acquisition. [Participants and Methods] We compared the time spent and acquired shapes among the plaster of Paris bandage, plastic cast, and trace methods in 30 limbs of 15 healthy participants. Three-dimensional scans of the lower legs of participants were used as references to compare the three methods. [Results] The plastic cast method required less time than the plaster of Paris bandage method and provided a more accurate shape than the trace method did. However, the plastic cast method resulted in an increased overall width and circumferential diameter owing to the thickness of the stockinette and plastic cast. [Conclusion] The plastic cast method may be useful in reducing the time and burden of fabricating metal strut ankle-foot orthoses. The use of slightly narrow dimensions during the metal strut bending process can account for the increased width and diameter.

8.
Artículo en Inglés | MEDLINE | ID: mdl-39099251

RESUMEN

Not applicable for Letter.

9.
Chemosphere ; 364: 143007, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39098347

RESUMEN

High-level radioactive waste needs to be safely stored for a long time in a deep geological repository by using a multi-barrier system. In this system, suitable barrier materials are selected that ideally show long-term stability to prevent early radionuclide release into the biosphere. In this study, different container matals (copper and cast iron) and pore water compositions (Opalinus Clay pore water and saline cap rock solution) were combined with Bavarian bentonite in static batch experiments to investigate microbial-influenced corrosion. The increasing concentration of iron and copper in the solution as well as detected corrosion products on the metal surface are indicative of anaerobic corrosion of the respective metals during an incubation of 400 days at 37 °C. However, although the intrinsic microbial bentonite community was stimulated with either lactate or H2, an acceleration of cast iron- and copper corrosion did not occur. Furthermore, neither corrosive bacteria nor conventional bacterial corrosion products, such as metal sulfides, were detected in any of the analyzed samples. The analyses of geochemical parameters (e.g. ferrous iron-, iron-, copper- and potassium concentrations as well as redox potentials) showed significant changes in some cast iron- and copper-containing setups, but these changes did not correlate with the microbial community structure in the respective microcosms, as confirmed by statistical analyses. Hence, the analyzed Bavarian bentonite (type B25) showed no significant contribution to cast iron and copper corrosion under the applied conditions after 400 days of incubation. From this perspective, bentonite B25 could be a suitable candidate as a geotechnical barrier in future repositories.

10.
Materials (Basel) ; 17(15)2024 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-39124406

RESUMEN

In this paper, enhancing the tribological characteristics of novel cast metallic materials-hybrid multi-component cast irons-by applying a strengthening heat treatment is described. The experimental materials were the cast alloys of a nominal composition (5 wt.% W, 5 wt.% Mo, 5 wt.% V, 10 wt.% Cr, 2.5 wt.% Ti, Fe is a balance) supplemented with 0.3-1.1 wt.% C and 1.5-2.5 wt.% B (total of nine alloys). The heat treatment was oil-quenching followed by 200 °C tempering. The quench temperature (QT) varied in the range of 900-1200 °C, with a step of 50 °C (with a 2-h holding at QT). The correlation of the QT with microstructure and properties was estimated using microstructure/worn surface characterization, differential scanning calorimetry, hardness measurement, and three-body-abrasive wear testing (using Al2O3 particles). The as-cast alloys had a multi-phase structure consisting of primary and/or eutectic borocarbide M2(B,C)5, carboborides M(C,B), M7(C,B)3, M3(C,B), and the matrix (ferrite, martensite, pearlite/bainite) in different combinations and volume fractions. Generally, the increase in the quenching temperature resulted in a gradual increase in hardness (maximally to 66-67 HRC) and a decrease in the wear rate in most alloys. This was due to the change in the phase-structure state of the alloys under quenching, namely, the secondary carboboride precipitation, and replacing ferrite and pearlite/bainite with martensite. The wear rate was found to be inversely proportional to bulk hardness. The maximum wear resistance was attributed to QT = 1150-1200 °C, when the wear rate of the alloys was lowered by three to six times as compared to the as-cast state. With the QT increase, the difference in the wear rate of the alloys decreased by three times. The highest abrasive resistance was attributed to the alloys with 1.1 wt.% C, which had a 2.36-3.20 times lower wear rate as compared with that of the reference alloy (13 wt.% Cr cast iron, hardness of 66 HRC). The effects of carbon and boron on hardness and wear behavior are analyzed using the regression models developed according to the factorial design procedure. The wear mechanisms are discussed based on worn surface characterization.

11.
Eur J Med Res ; 29(1): 410, 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39118170

RESUMEN

Superior mesenteric artery syndrome (SMAS) is a rare and unpredictable complication after correction spine surgery for adolescent idiopathic scoliosis (AIS). The management of this condition is poorly investigated, with controversial outcomes. This investigation systematically reviewed current evidence on pathogenesis, risk factors, management, and outcomes of SMAS following correction spine surgery for AIS. The present systematic review was conducted according to the 2020 PRISMA statement. All the included investigations reported SMAS presentation following scoliosis correction surgery in AIS. 29 articles with 61 eligible patients were included in this review. The mean age of the patients was 15.8 ± 7.2 years. The mean weight was 45.3 ± 8.0 kg, the mean height 159.6 ± 13.6 cm, and the mean BMI 16.5 ± 2.9 kg/m2. The mean duration of the treatment for SMAS was 21.6 ± 10.3 days. The mean interval between spine surgery and symptoms of SAMS was 69 days, with high between-studies variability (3 days to 4 years). Prompt identification of risk factors and an early diagnosis are necessary to manage SMAS and reduce the risk of complications. Additional investigations are required to establish risk factors and diagnostic criteria.Level of evidence Level IV, systematic review.


Asunto(s)
Escoliosis , Síndrome de la Arteria Mesentérica Superior , Humanos , Escoliosis/cirugía , Síndrome de la Arteria Mesentérica Superior/etiología , Adolescente , Complicaciones Posoperatorias/etiología , Factores de Riesgo
12.
Foot Ankle Int ; : 10711007241268147, 2024 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-39188121

RESUMEN

BACKGROUND: Charcot neuroosteoarthropathy (CNO) is characterized with increased osteoclastic activity that can be curbed with antiresorptive agents. Chronic kidney disease (CKD) precludes bisphosphonates but anti-receptor activator of nuclear factor-B ligand (anti-RANKL) antibody, denosumab, can be contemplated in CKD. We investigated denosumab for active CNO of foot in CKD for CNO remission. METHODS: During the study period, 446 persons of diabetes with unilateral, active CNO of foot and CKD were identified and 78 were finally enrolled. Patients received either 60 mg denosumab (single-dose, subcutaneous) along with standard of care (SoC) as total contact cast (TCC) (group A; n = 26) or SoC (group B; n = 52) only. Patients were followed every 4 weeks until CNO remission and subsequently every 8 weeks until 48 weeks following remission. Remission was defined as temperature difference <2 °C between 2 feet confirmed twice (4 weeks apart) with clinical resolution of signs of inflammation. The primary outcome studied was proportion of patients achieving remission within 48 weeks and the time to remission. RESULTS: Median age was 56.5 (48.8-65) and 57 (48.5-61.2) years, P = .57; duration of diabetes 16 (10-25.3) and 14.9 (10-19) years, P = .151; and estimated glomerular filtration rate 44.8 (21.1-65.6) and 45.7 (32.9-55.7) mL/min/1.73 m2, P = .771, in group A and B, respectively. Median temperature difference at presentation between the affected and opposite foot was 3.4 °C (2.7-6.9) and 3.2 °C (2.2-4.0), P = .119, respectively. All patients achieved remission in group A (100%) compared with 42 (80.8%) in group B (P = .006) (hazard ratio 0.52, 95% CI: 0.32-0.87; P = .012). The median time to remission was similar in the 2 groups (15 [11-25] and 17.5 [14-31.5] weeks, P = .229, respectively). 25-Hydroxyvitamin D3 >14 ng/mL was significantly associated (OR 9.5, 95% CI 1.04-87.5, P = .045) with remission. CONCLUSION: Anti-RANKL antibody added to SoC (TCC) induces remission of active foot CNO in greater proportions of patients with diabetes and CKD.

13.
Orthopadie (Heidelb) ; 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-39160373

RESUMEN

Tibialis spastic varus foot (TSVF) is an uncommon clinical entity primarily associated with tarsal coalition. This case report presents a rare instance of TSVF without tarsal coalition in an 8­year-old male patient. Successful treatment was achieved through a conservative approach involving botulinum toxin injections and a plaster cast, highlighting the potential of nonsurgical interventions for this rare condition.

14.
Int Orthod ; 22(4): 100903, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39181038

RESUMEN

PURPOSES: The aim of this study was to examine the effects of post material type and the presence of ferrules on the torque and intrusion load of the upper central tooth using finite element analysis. METHODS: The upper central tooth and surrounding tissues (cortical bone, cancellous bone, and periodontal ligament) were modelled in three dimensions using the Spaceclaim software. Five simulated models (SM) different modifications were made to this main model: metal cast post (SM1) and glass fiber post-core with zirconium crown and without a ferrule (SM2), metal cast (SM3) post and glass fiber post with a ferrule and zirconium crown (SM4) and only zirconium crown (SM5). In all five simulations, in order to simulate lingual root torque movement, a total load of 40 grams was applied to the bracket slot as 20 grams of force couples and in order to simulate intrusion movement, a load of 40 grams was applied to the superior wall of the bracket slot. The stress caused by the applied loads on the root surfaces was determined using finite element analysis. Maximum principal stress (MPS) value was used in the comparison. RESULTS: The highest root surface MPS values for both intrusion and torque loads belonged to SM2 (3.864 and 0.379MPa, respectively). The presence of ferrules in both intrusion and torque loads reduced the stress by approximately half (from 3.864 to 2.004MPa). In all five models, the radicular area with higher stress was located in the cervical third on the lingual surface when both torque and intrusion loads were applied. CONCLUSION: The amount and localization of stress was affected by the type of post material. The variation in stress values between the materials remains within a safe range (0.099 and 3.87MPa), making both materials suitable for use under orthodontic forces.

15.
Sci Total Environ ; : 175727, 2024 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-39181261

RESUMEN

Ultrafine particles (UFP) are the smallest atmospheric particulate matter linked to air pollution-related diseases. The extent to which UFP's physical and chemical properties contribute to its toxicity remains unclear. It is hypothesized that UFP act as carriers for chemicals that drive biological responses. This study explores robust methods for generating reference UFP to understand these mechanisms and perform toxicological tests. Two types of combustion-related UFP with similar elemental carbon cores and physical properties but different organic loads were generated and characterized. Human alveolar epithelial cells were exposed to these UFP at the air-liquid interface, and several toxicological endpoints were measured. UFP were generated using a miniCAST under fuel-rich conditions and immediately diluted to minimize agglomeration. A catalytic stripper and charcoal denuder removed volatile gases and semi-volatile particles from the surface. By adjusting the temperature of the catalytic stripper, UFP with high and low organic content was produced. These reference particles exhibited fractal structures with high reproducibility and stability over a year, maintaining similar mass and number concentrations (100 µg/m3, 2.0·105 #/cm3) and a mean particle diameter of about 40 nm. High organic content UFP had significant PAH levels, with benzo[a]pyrene at 0.2 % (m/m). Toxicological evaluations revealed that both UFP types similarly affected cytotoxicity and cell viability, regardless of organic load. Higher xenobiotic metabolism was noted for PAH-rich UFP, while reactive oxidation markers increased when semi-volatiles were stripped off. Both UFP types caused DNA strand breaks, but only the high organic content UFP induced DNA oxidation. This methodology allows modification of UFP's chemical properties while maintaining comparable physical properties, linking these variations to biological responses.

16.
Cureus ; 16(7): e64214, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39130933

RESUMEN

Pigment-induced acute kidney injury (AKI) is an important and preventable complication of rhabdomyolysis or hemolysis. It is characterized by the release of free heme pigment (myoglobin or hemoglobin) in the circulation, leading to direct injury of the proximal tubule and distal tubule obstruction by pigment cast. We are reporting eight cases of pigment-induced AKI, including six cases of myoglobin cast nephropathy and two cases of hemoglobin cast nephropathy. The causes of rhabdomyolysis were strenuous exercise, infection/febrile illness, and drug-induced neuroleptic malignant syndrome. Paroxysmal nocturnal hemoglobinuria and anti-tuberculosis treatment (rifampicin and isoniazid) had led to hemoglobin cast nephropathy each in one case. Seven cases had severe renal failure requiring dialysis. Short-term renal outcome was favorable. However, long-term follow-up is necessary to determine whether pigment-induced AKI has delayed sequelae. Therefore, clinicians should consider rhabdomyolysis or hemolysis as potential hidden causes of AKI in diverse clinical conditions, especially those of non-traumatic origin, to achieve an accurate diagnosis.

17.
Rozhl Chir ; 103(6): 219-223, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38991785

RESUMEN

INTRODUCTION: Volkmann's ischaemic contracture (VIC) is a disabling condition resulting from tissue necrosis due to impaired vascular supply to the limb. Over the years VIC has become rare in developed countries with many different aetiologies described. It was alarming to have high incidence of established VIC in our practice in Nepal. A detailed analysis was conducted to accurately describe this issue. METHODS: We collected 47 cases of VIC over six years and noted the age, sex, district of origin and cause of VIC, duration of injury to presentation, and the grade of VIC. Then we compared these characteristics of VIC of each Nepal province and created a map to show the problematic regions. RESULTS: Out of 47 patients, 46 could have been prevented by an early treatment. The most common cause was a tight cast in 25 patients (53.19%), followed by unintentionally self-caused VIC by applying tight bandages in 21 patients (44.68%). Most cases came from province 6 (29.78%). Our group included three mild (6.4%), 35 moderate (74.5%) and nine severe (19.1%) cases of VIC. Only 14 cases (29.78%) had a timely fasciotomy in the past. CONCLUSION: VIC is an irreversible complication of the compartment syndrome which is an easily preventable condition in the setting of developing countries. Our focus should, therefore, aim at preventing such disastrous conditions as 97.87% of cases we encountered could have been avoided by proper primary care. In the case of Nepal most cases came from province 6 and province 3.


Asunto(s)
Países en Desarrollo , Contractura Isquémica , Humanos , Masculino , Nepal/epidemiología , Femenino , Adulto , Contractura Isquémica/etiología , Persona de Mediana Edad , Adolescente , Niño , Extremidad Superior/irrigación sanguínea , Adulto Joven , Preescolar , Anciano
18.
Pediatr Dermatol ; 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38994911

RESUMEN

PLACK syndrome (OMIM 616295) is a rare genodermatosis associated with peeling skin, leukonychia, acral punctate keratosis, cheilitis, and knuckle pads and is caused by loss-of-function mutations in the CAST gene, which encodes calpastatin, a calcium-dependent protease. This case report highlights a case of PLACK syndrome presenting with the unique findings of striate hyperkeratosis on the palms as well as life-threatening cardiomyopathy. We review why CAST mutations might impact cardiac function and raise awareness of the potential association between PLACK syndrome and cardiac manifestations.

19.
Adv Med Educ Pract ; 15: 649-657, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39007125

RESUMEN

Purpose: To determine the effect of experience and tooth location on the finish line width and angle of crown preparations performed by undergraduate students. Methods: Eighty full metal crown preparations on typodont teeth were divided into four groups: Group 1: 20 preparations performed on mandibular first molar in the first semester. Group 2: 20 preparations performed on mandibular first molar in the second semester. Group 3: 20 preparations performed on mandibular second molar in the first semester. Group 4: 20 preparations performed on mandibular second molar in the second semester. All prepared teeth were scanned, and the finish line width and angles were measured at 8 different locations. Paired t-test in the SPSS software was used to compare and determine the effect of experience and tooth location on the students' performance. Results: There was a statistically significant difference in the mandibular first molar finish line width between the first and second semesters for the same student in the distal, distolingual, and mesiobuccal areas of the tooth. There was a statistically significant increase in finish line width between first and second molars in the distobuccal, distal, distolingual, lingual, and mesial side of the tooth. Regarding the finish line angle, there was a statistically significant difference between the first and second semesters on the distal side of the tooth. There was a statistically significant increase in finish line angle between first and second molars in the distobuccal side of the tooth. Conclusion: As students gain more experience in different types of tooth preparations, they tend to produce a wider finish line than that recommended for full metal crown preparation. The tooth location in the mouth influences the width and angle of the finish line hence the more inaccessible areas on the tooth have a wider finish line.

20.
Sci Total Environ ; 949: 174878, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39047841

RESUMEN

Earthworms are pivotal in soil ecosystems due to their crucial role in shaping soil characteristics through casts and burrow walls. Previous research has predominantly focused on the direct impact of soil pollution on live earthworms, overlooking the subsequent effects on earthworm-mediated soil, such as casts and burrow walls. Using 2D-terraria as incubation containers and the geophagous earthworm species Metaphire guillelmi, this study assessed the change in various properties of earthworm-mediated soil in both uncontaminated soils and Cd- and Pye-contaminated soils. Overall, both Cd and Pye overall improved the ammonium nitrogen (NH4+-N), Olsen's phosphorus (Olsen-P) levels, and invertase and catalase activities while decreasing catalase activities in earthworm-mediated soil. They also fluctuating affected the pH, soil organic matter (SOM) content, soil urease, alkaline phosphatase activities, and microbial functional genes in the cast and burrow walls. These results indicated that earthworms remained crucial "ecosystem engineers" even in polluted soil. Additionally, differences were observed in the responses of properties between casts and burrow walls, showing unequal contributions of transit-through-gut and burrowing processes to soil modification. Specifically, transit-through-gut was found to have a more significant influence on soil NH4+-N and Olsen-P content compared to burrowing behavior. Regarding the pattern of microbial functional genes in earthworm-associated compartments, results revealed that they differed significantly in casts from those in bulk soil and burrow walls under unpolluted conditions, with pollution-enhancing disparities among compartments. Furthermore, NH4+-N and Olsen-P content, urease, and catalase activities in burrow walls and/or casts were identified as potential biomarkers for soil pollution, exhibiting a clear dose-effect relationship. Developing such biomarkers could address ethical concerns related to conventional earthworm biomarkers that require sacrificing earthworms. This study provides insights into the consequences of soil pollution on earthworm-mediated soil components, highlighting the importance of considering the indirect effects of contaminants on soil ecosystems.


Asunto(s)
Cadmio , Oligoquetos , Pirenos , Contaminantes del Suelo , Suelo , Oligoquetos/fisiología , Animales , Contaminantes del Suelo/análisis , Suelo/química , Cadmio/análisis , Fósforo/análisis
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