Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 286
Filter
2.
Article in English | MEDLINE | ID: mdl-38748935

ABSTRACT

OBJECTIVE: Our primary aim was to identify radiomic ultrasound features that can distinguish benign from malignant adnexal masses with solid ultrasound morphology, and primary invasive from metastatic solid ovarian masses, and to develop ultrasound-based machine learning models that include radiomics features to discriminate between benign and malignant solid adnexal masses. Our secondary aim was to compare the diagnostic performance of our radiomics models with that of the ADNEX model and subjective assessment by an experienced ultrasound examiner. METHODS: This is a retrospective observational single center study. Patients with a histological diagnosis of an adnexal tumor with solid morphology at preoperative ultrasound examination performed between 2014 and 2021 were included. The patient cohort was split into training and validation sets with a ratio of 70:30 and with the same proportion of benign and malignant (borderline, primary invasive and metastatic) tumors in the two subsets. The extracted radiomic features belonged to two different families: intensity-based statistical features and textural features. Models to predict malignancy were built based on a random forest classifier, fine-tuned using 5-fold cross-validation over the training set, and tested on the held-out validation set. The variables used in model building were patient's age, and those radiomic features that were statistically significantly different between benign and malignant adnexal masses (Wilcoxon-Mann-Whitney Test with Benjamini-Hochberg correction for multiple comparisons) and assessed as not redundant based on the Pearson correlation coefficient. We describe discriminative ability as area under the receiver operating characteristics curve (AUC) and classification performance as sensitivity and specificity. RESULTS: 326 patients were identified and 775 preoperative ultrasound images were analyzed. 68 radiomic features were extracted, 52 differed statistically significantly between benign and malignant tumors in the training set, and 18 features were selected for inclusion in model building. The same 52 radiomic features differed statistically significantly between benign, primary invasive malignant and metastatic tumors. However, the values of the features manifested overlap between primary malignant and metastatic tumors and did not differ statistically significantly between them. In the validation set, 25/98 tumors (25.5%) were benign, 73/98 (74.5%) were malignant (6 borderline, 57 primary invasive, 10 metastases). In the validation set, a model including only radiomics features had an AUC of 0.80, and 78% sensitivity and 76% specificity at its optimal risk of malignancy cutoff (68% based on Youden's index). The corresponding results for a model including age and radiomics features were 0.79, 86% and 56% (cutoff 60% based on Youden's method), while those of the ADNEX model were 0.88, 99% and 64% (at 20% malignancy cutoff). Subjective assessment had sensitivity 99% and specificity 72%. CONCLUSIONS: Even though our radiomics models had discriminative ability inferior to that of the ADNEX model, our results are promising enough to justify continued development of radiomics analysis of ultrasound images of adnexal masses. This article is protected by copyright. All rights reserved.

3.
Viruses ; 16(5)2024 05 06.
Article in English | MEDLINE | ID: mdl-38793617

ABSTRACT

The cacao swollen shoot disease (CSSD) caused by a complex of badnavirus species presents a major challenge for cacao production in West Africa, especially Ghana and Côte d'Ivoire. In this study, CSSD species detection efficiency, diversity, and geographic distribution patterns in cacao plantations in Ghana and Côte d'Ivoire were investigated through field surveillance, PCR detection assays, sequencing of positive amplicons, and phylogeographic clustering. Cumulatively, the detection efficiency of the tested CSSD primer sets that were targeting the movement protein domain of the virus ranged from 0.15% (CSSD-3 primer) to 66.91% (CSSD-1 primer) on all the symptomatic cacao leaf samples assessed. The identified CSSD species differed phylogenetically and overlapped in distribution, with the cacao swollen shoot Togo B virus (CSSTBV) (n = 588 sequences) being the most prevalent and widely distributed compared to the other CSSD species that were encountered in both countries. Geographically, the cacao swollen shoot CE virus (CSSCEV) species (n = 124 sequences) that was identified was largely restricted to the bordering regions of Ghana and Côte d'Ivoire. These results provide updated knowledge of the geographic distribution of the key CSSD species and their diagnostic efficiency and, thus, provide guidance in identifying locations for structured testing of cacao germplasm and optimal diagnostics for the predominant CSSD species in Ghana and Côte d'Ivoire.


Subject(s)
Badnavirus , Cacao , Phylogeny , Plant Diseases , Cacao/virology , Cote d'Ivoire/epidemiology , Ghana/epidemiology , Badnavirus/genetics , Badnavirus/isolation & purification , Badnavirus/classification , Plant Diseases/virology , Prevalence , Phylogeography
4.
Article in English | MEDLINE | ID: mdl-38477179

ABSTRACT

OBJECTIVES: The aim is to evaluate the ability of the Assessment of Different NEoplasias in the adneXa model (ADNEX) and the International Ovarian Tumour Analysis (IOTA) two-step strategy to predict malignancy in adnexal masses detected in an outpatient low-risk setting, and to estimate the risk of complications in masses with benign ultrasound morphology managed with clinical and ultrasound follow-up. METHODS: This single center (Hospital Universitari Dexeus Barcelona) study was performed using interim data of the ongoing prospective observational IOTA phase 5 study. The primary aim of the IOTA 5 study is to describe the cumulative incidence of complications during follow-up of adnexal masses classified as benign on ultrasound. Consecutive patients with adnexal masses detected between June 2012 and September 2016 in a private center offering screening for gynecological cancers were included and followed-up until February 2020. Tumors were classified as benign or malignant based on histology (if patients underwent surgery) or outcome of clinical and ultrasound follow-up at 12 (±2) months. Multiple imputation was used when follow-up information was uncertain. The ability of the ADNEX model without CA125 and of the IOTA two-step strategy to distinguish benign from malignant masses was evaluated retrospectively using the prospectively collected data. We describe performance as discrimination (area under the receiver operating characteristic curve, AUC), calibration, classification (sensitivity and specificity) and clinical utility (Net Benefit). In the group of patients with a benign looking mass selected for conservative management we evaluated the occurrence of spontaneous resolution or any mass complication during the first 5 years of follow-up by assessing the cumulative incidence for malignancy, torsion, cyst rupture, or minor mass complications (inflammation, infection, or adhesions) and the time to occurrence of an event. RESULTS: A total of 2654 patients were recruited to the study. After application of exclusion criteria, 2039 patients with a newly detected mass were included for the model validation. 1684 (82.6%) masses were benign, 49 (2.4%) masses were malignant and for 306 (15.0%) masses the outcome was uncertain and imputed. The AUC was 0.95 (95% CI 0.89-0.98) for ADNEX and 0.94 (95% CI 0.88-0.97) for the two-step strategy. Calibration performance could not be meaningfully interpreted due to few malignancies resulting in very wide confidence intervals. The two-step strategy had better clinical utility than ADNEX at malignancy risk thresholds < 3%. 1472 (72%) patients had a mass judged to be benign based on pattern recognition by an experienced ultrasound examiner and were managed with clinical and ultrasound follow-up. In this group, the 5-year cumulative incidence was 66% for spontaneous resolution of the mass (95% CI 63-69), 0% for torsion (95%CI 0-0.002), 0.1% for cyst rupture (<0.1-0.6), 0.2% for a borderline tumor (<0.1-0.6), and 0.2% (0.1-0.6) for invasive malignancy. CONCLUSIONS: The ADNEX model and IOTA two-step strategy performed well to distinguish benign from malignant adnexal masses detected in a low-risk population. Conservative management is safe for masses with benign ultrasound appearance in such a population. This article is protected by copyright. All rights reserved.

5.
Proc Natl Acad Sci U S A ; 121(8): e2320764121, 2024 Feb 20.
Article in English | MEDLINE | ID: mdl-38346192

ABSTRACT

Many animal species rely on the Earth's magnetic field during navigation, but where in the brain magnetic information is processed is still unknown. To unravel this, we manipulated the natural magnetic field at the nest entrance of Cataglyphis desert ants and investigated how this affects relevant brain regions during early compass calibration. We found that manipulating the Earth's magnetic field has profound effects on neuronal plasticity in two sensory integration centers. Magnetic field manipulations interfere with a typical look-back behavior during learning walks of naive ants. Most importantly, structural analyses in the ants' neuronal compass (central complex) and memory centers (mushroom bodies) demonstrate that magnetic information affects neuronal plasticity during early visual learning. This suggests that magnetic information does not only serve as a compass cue for navigation but also as a global reference system crucial for spatial memory formation. We propose a neural circuit for integration of magnetic information into visual guidance networks in the ant brain. Taken together, our results provide an insight into the neural substrate for magnetic navigation in insects.


Subject(s)
Ants , Animals , Ants/physiology , Learning/physiology , Brain , Neuronal Plasticity/physiology , Magnetic Phenomena , Homing Behavior/physiology , Cues , Desert Climate
6.
Biomimetics (Basel) ; 9(1)2024 Jan 17.
Article in English | MEDLINE | ID: mdl-38248626

ABSTRACT

The quasi-static regime of friction between a rigid steel indenter and a soft elastomer with high adhesion is studied experimentally. An analysis of the formally calculated dependencies of a friction coefficient on an external load (normal force) shows that the friction coefficient monotonically decreases with an increase in the load, following a power law relationship. Over the entire range of contact loads, a friction mode is realized in which constant shear stresses are maintained in the tangential contact, which corresponds to the "adhesive" friction mode. In this mode, Amonton's law is inapplicable, and the friction coefficient loses its original meaning. Some classical works, which show the existence of a transition between "adhesive" and "normal" friction, were analyzed. It is shown that, in fact, there is no such transition. A computer simulation of the indentation process was carried out within the framework of the boundary element method, which confirmed the experimental results.

7.
Ultrasound Obstet Gynecol ; 63(3): 399-407, 2024 03.
Article in English | MEDLINE | ID: mdl-37774092

ABSTRACT

OBJECTIVE: To describe the clinical and ultrasound characteristics of recurrent granulosa cell and Sertoli-Leydig cell tumors. METHODS: This was a retrospective observational study performed at Fondazione Policlinico Universitario A. Gemelli, Istituto di Ricovero e Cura a Carattere Scientifico, IRCCS, Rome (Gemelli center), Italy. Patients with a histological diagnosis of recurrent granulosa cell tumor or Sertoli-Leydig cell tumor were identified from the database of the Department of Gynecological Oncology. Those who had undergone a preoperative ultrasound examination at the Gemelli center between 2012 and 2020 were included, and the data retrieved from the original ultrasound reports. In all of these reports, the recurrent tumors were described using International Ovarian Tumor Analysis (IOTA) terminology. If a patient had more than one episode of relapse, information from all episodes was collected. If there was more than one recurrent tumor at the same ultrasound examination, all tumors were included. One expert sonographer also reviewed all available ultrasound images to identify typical ultrasound patterns using pattern recognition. RESULTS: We identified 30 patients with a histological diagnosis of recurrent granulosa cell tumor (25 patients, 55 tumors) or Sertoli-Leydig cell tumor (five patients, seven tumors). All 30 had undergone at least one preoperative ultrasound examination at the Gemelli center and were included. These women had a total of 66 episodes of relapse, of which a preoperative ultrasound examination had been performed at the Gemelli center in 34, revealing 62 recurrent lesions: one in 22/34 (64.7%) episodes of relapse, two in 4/34 (11.8%) episodes and three or more in 8/34 (23.5%) episodes. Most recurrent granulosa cell tumors (38/55, 69.1%) and recurrent Sertoli-Leydig tumors (6/7, 85.7%) were classified as solid or multilocular-solid tumors, while 8/55 (14.5%) recurrent granulosa cell tumors and 1/7 (14.3%) recurrent Sertoli-Leydig cell tumors were unilocular cysts and 9/55 (16.4%) recurrent granulosa cell tumors were multilocular cysts. The nine unilocular cysts had contents that were anechoic (n = 2) or had low-level echogenicity (n = 7), had either smooth (n = 4) or irregular (n = 5) internal cyst walls, and ranged in largest diameter from 8 to 38 mm, with three being < 20 mm and five being 20-30 mm. On retrospective review of the images, two typical ultrasound patterns were described: small solid tumor measuring < 2 cm (15/62, 24.2%) and tumor with vascularized echogenic ground-glass-like content (12/62, 19.4%). CONCLUSIONS: Some granulosa cell and Sertoli-Leydig cell recurrences manifest one of two typical ultrasound patterns, while some appear as unilocular cysts. These are usually classified as benign, but in patients being followed up for a granulosa cell tumor or Sertoli-Leydig cell tumor, a unilocular cyst should be considered suspicious of recurrence. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Cysts , Genital Diseases, Female , Granulosa Cell Tumor , Ovarian Neoplasms , Sertoli-Leydig Cell Tumor , Sex Cord-Gonadal Stromal Tumors , Pregnancy , Male , Humans , Female , Sertoli-Leydig Cell Tumor/diagnostic imaging , Granulosa Cell Tumor/diagnostic imaging , Neoplasm Recurrence, Local/diagnostic imaging , Ultrasonography , Ovarian Neoplasms/diagnostic imaging , Sex Cord-Gonadal Stromal Tumors/diagnostic imaging , Recurrence , Stromal Cells
8.
Ultrasound Obstet Gynecol ; 63(4): 556-563, 2024 04.
Article in English | MEDLINE | ID: mdl-37927006

ABSTRACT

OBJECTIVES: To assess the ability of the International Endometrial Tumor Analysis (IETA)-1 polynomial regression model to estimate the risk of endometrial cancer (EC) and other intracavitary uterine pathology in women without abnormal uterine bleeding. METHODS: This was a retrospective study, in which we validated the IETA-1 model on the IETA-3 study cohort (n = 1745). The IETA-3 study is a prospective observational multicenter study. It includes women without vaginal bleeding who underwent a standardized transvaginal ultrasound examination in one of seven ultrasound centers between January 2011 and December 2018. The ultrasonography was performed either as part of a routine gynecological examination, during follow-up of non-endometrial pathology, in the work-up before fertility treatment or before treatment for uterine prolapse or ovarian pathology. Ultrasonographic findings were described using IETA terminology and were compared with histology, or with results of clinical and ultrasound follow-up of at least 1 year if endometrial sampling was not performed. The IETA-1 model, which was created using data from patients with abnormal uterine bleeding, predicts four histological outcomes: (1) EC or endometrial intraepithelial neoplasia (EIN); (2) endometrial polyp or intracavitary myoma; (3) proliferative or secretory endometrium, endometritis, or endometrial hyperplasia without atypia; and (4) endometrial atrophy. The predictors in the model are age, body mass index and seven ultrasound variables (visibility of the endometrium, endometrial thickness, color score, cysts in the endometrium, non-uniform echogenicity of the endometrium, presence of a bright edge, presence of a single dominant vessel). We analyzed the discriminative ability of the model (area under the receiver-operating-characteristics curve (AUC); polytomous discrimination index (PDI)) and evaluated calibration of its risk estimates (observed/expected ratio). RESULTS: The median age of the women in the IETA-3 cohort was 51 (range, 20-85) years and 51% (887/1745) of the women were postmenopausal. Histology showed EC or EIN in 29 (2%) women, endometrial polyps or intracavitary myomas in 1094 (63%), proliferative or secretory endometrium, endometritis, or hyperplasia without atypia in 144 (8%) and endometrial atrophy in 265 (15%) women. The endometrial sample had insufficient material in five (0.3%) cases. In 208 (12%) women who did not undergo endometrial sampling but were followed up for at least 1 year without clinical or ultrasound signs of endometrial malignancy, the outcome was classified as benign. The IETA-1 model had an AUC of 0.81 (95% CI, 0.73-0.89, n = 1745) for discrimination between malignant (EC or EIN) and benign endometrium, and the observed/expected ratio for EC or EIN was 0.51 (95% CI, 0.32-0.82). The model was able to categorize the four histological outcomes with considerable accuracy: the PDI of the model was 0.68 (95% CI, 0.62-0.73) (n = 1532). The IETA-1 model discriminated very well between endometrial atrophy and all other intracavitary uterine conditions, with an AUC of 0.96 (95% CI, 0.95-0.98). Including only patients in whom the endometrium was measurable (n = 1689), the model's AUC was 0.83 (95% CI, 0.75-0.91), compared with 0.62 (95% CI, 0.52-0.73) when using endometrial thickness alone to predict malignancy (difference in AUC, 0.21; 95% CI, 0.08-0.32). In postmenopausal women with measurable endometrial thickness (n = 848), the IETA-1 model gave an AUC of 0.81 (95% CI, 0.71-0.91), while endometrial thickness alone gave an AUC of 0.70 (95% CI, 0.60-0.81) (difference in AUC, 0.11; 95% CI, 0.01-0.20). CONCLUSION: The IETA-1 model discriminates well between benign and malignant conditions in the uterine cavity in patients without abnormal bleeding, but it overestimates the risk of malignancy. It also discriminates well between the four histological outcome categories. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Endometrial Hyperplasia , Endometrial Neoplasms , Endometritis , Polyps , Uterine Neoplasms , Female , Humans , Young Adult , Adult , Middle Aged , Aged , Aged, 80 and over , Male , Endometritis/pathology , Retrospective Studies , Endometrial Neoplasms/diagnostic imaging , Endometrial Neoplasms/pathology , Endometrium/diagnostic imaging , Endometrium/pathology , Uterine Neoplasms/diagnostic imaging , Uterine Neoplasms/pathology , Uterine Hemorrhage/diagnostic imaging , Uterine Hemorrhage/pathology , Ultrasonography , Endometrial Hyperplasia/diagnostic imaging , Endometrial Hyperplasia/pathology , Polyps/diagnostic imaging , Polyps/pathology , Atrophy/pathology
9.
Biomimetics (Basel) ; 8(6)2023 Oct 07.
Article in English | MEDLINE | ID: mdl-37887608

ABSTRACT

In reported experiments, a steel indenter was pressed into a soft elastomer layer under varying inclination angles and subsequently was detached under various inclination angles too. The processes of indentation and detachment were recorded with a video camera, and the time dependences of the normal and tangential components of the contact force and the contact area, as well as the average contact pressure and average tangential stresses, were measured as functions of the inclination angle. Based on experimental results, a simple theoretical model of the indentation process is proposed, in which tangential and normal contacts are considered independently. Both experimental and theoretical results show that at small indentation angles (when the direction of motion is close to tangential), a mode with elastomer slippage relative to the indenter is observed, which leads to complex dynamic processes-the rearrangement of the contact boundary and the propagation of elastic waves (similar to Schallamach waves). If the angle is close to the normal angle, there is no slipping in the contact plane during the entire indentation (detachment) phase.

10.
Sensors (Basel) ; 23(12)2023 Jun 10.
Article in English | MEDLINE | ID: mdl-37420645

ABSTRACT

Thermal stability is an important feature of the materials used as components and parts of sensors and other devices of nanoelectronics. Here we report the results of the computational study of the thermal stability of the triple layered Au@Pt@Au core-shell nanoparticles, which are promising materials for H2O2 bi-directional sensing. A distinct feature of the considered sample is the raspberry-like shape, due to the presence of Au nanoprotuberances on its surface. The thermal stability and melting of the samples were studied within classical molecular dynamics simulations. Interatomic forces were computed within the embedded atom method. To investigate the thermal properties of Au@Pt@Au nanoparticles, structural parameters such as Lindemann indexes, radial distribution functions, linear distributions of concentration, and atomistic configurations were calculated. As the performed simulations showed, the raspberry-like structure of the nanoparticle was preserved up to approximately 600 K, while the general core-shell structure was maintained up to approximately 900 K. At higher temperatures, the destruction of the initial fcc crystal structure and core-shell composition was observed for both considered samples. As Au@Pt@Au nanoparticles demonstrated high sensing performance due to their unique structure, the obtained results may be useful for the further design and fabrication of the nanoelectronic devices that are required to work within a certain range of temperatures.


Subject(s)
Gold , Metal Nanoparticles , Hydrogen Peroxide , Molecular Dynamics Simulation
12.
Metabolites ; 13(5)2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37233650

ABSTRACT

Metabolomic analysis methods were employed to determine biomarkers for various chronic kidney diseases (CKDs). Modern analytical methods were developed and applied successfully to find a specific metabolomic profile in urine samples from CKD and Balkan endemic nephropathy (BEN) patients. The aim was to explore a specific metabolomic profile defined by feasible/easy-to-identify molecular markers. Urine samples were collected from patients with CKDs and BEN, and from healthy subjects from endemic and nonendemic areas in Romania. Metabolomic analysis of urine samples, extracted by the liquid-liquid extraction (LLE) method, was performed by gas chromatography-mass spectrometry (GC-MS). The statistical exploration of the results was performed through a principal component analysis (PCA) evaluation. Urine samples were statistically analyzed using a classification based on six types of metabolites. Most urinary metabolites are distributed in the center of a loading plot, meaning that these compounds do not represent significant markers for BEN. One of the most frequent and higher-concentration urinary metabolites in BEN patients was p-Cresol, a phenolic compound that implies a severe injury of the renal filtration function. The presence of p-Cresol was associated with protein-bound uremic toxins, which have specific functional groups such as indole and phenyl. In prospective studies for future investigation, prevention, and disease treatment, we suggest a larger sample size, sample extraction using other methods, and analysis using other chromatography techniques coupled with mass spectrometry, which can generate a more significant data set for statistical analysis.

13.
Front Med (Lausanne) ; 10: 1134786, 2023.
Article in English | MEDLINE | ID: mdl-36960336

ABSTRACT

Osteoarthritis is one of the most severe diseases of the human musculoskeletal system, and therefore, for many years, special attention has been paid to the search for effective methods of its treatment. However, even the most modern methods only in a limited number of cases in the early or intermediate stages of osteoarthritis lead to positive treatment results. In the later stages of development, osteoarthritis is practically incurable and most often ends with disability or the need for joint replacement for a large number of people. One of the main reasons hindering the development of osteoarthritis treatment methods is the peculiarities of articular cartilage, in which there is practically no vascular network and tissue homeostasis is carried out mainly due to the diffusion of nutrients present in the synovial fluid. In modern medicine, for the treatment of osteoarthritis, tissue engineering strategies have been developed based on the implantation of scaffolds populated with chondrogenic cells into the area of the defect. In vitro studies have established that these cells are highly mechanosensitive and, under the influence of mechanical stimuli of a certain type and intensity, their ability to proliferate and chondrogenesis increases. This property can be used to improve the efficiency of regenerative rehabilitation technologies based on the synergistic combination of cellular technologies, tissue engineering strategies, and mechanical tissue stimulation. In this work, using a regenerative rehabilitation mathematical model of local articular cartilage defects, numerical experiments were performed, the results of which indicate that the micro-and macro environment of the restored tissue, which changes during mechanical stimulation, has a significant effect on the formation of the extracellular matrix, and, consequently, cartilage tissue generally. The results obtained can be used to plan strategies for mechanical stimulation, based on the analysis of the results of cell proliferation experimental assessment after each stimulation procedure in vivo.

14.
Sage Open ; 13(1): 21582440221146135, 2023.
Article in English | MEDLINE | ID: mdl-36650826

ABSTRACT

Worldwide, an increase in cases and severity of domestic violence (DV) has been reported as a result of social distancing measures implemented to decrease the spreading of the Coronavirus Disease (COVID-19). As one's language can provide insight in one's mental health, this pre-registered study analyzed word use in a DV online support group, aiming to investigate the impact of the COVID-19 pandemic on DV victims in an ex post facto research design. Words reflecting social support and leisure activities were investigated as protective factors against linguistic indicators of depression in 5,856 posts from the r/domesticviolence subreddit and two neutral comparison subreddits (r/changemyview & r/femalefashionadvice). In the DV support group, the average number of daily posts increased significantly by 22% from pre- to mid-pandemic. Confirmatory analysis was conducted following a registered pre-analysis plan. DV victims used significantly more linguistic indicators of depression than individuals in the comparison groups. This did not change with the onset of COVID-19. The use of negative emotion words was negatively related to the use of social support words (Spearman's rho correlation coefficient [rho] = -0.110) and words referring to leisure activities (rho = -0.137). Pre-occupation with COVID-19 was associated with the use of negative emotion words (rho = 0.148). We conclude that language of DV victims is characterized by indicators of depression and this characteristic is stable over time. Concerns with COVID-19 could contribute to negative emotions, whereas social support and leisure activities could function to some degree as protective factors. A potential weakness of this study is its cross-sectional design and the lack of experimental control. Future studies could make use of natural language processing and other advanced methods of linguistic analysis to learn about the mental health of DV victims.

15.
Sensors (Basel) ; 23(1)2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36617054

ABSTRACT

Herein, we describe the design of a laboratory setup operating as a high-precision tribometer. The whole design procedure is presented, starting with a concept, followed by the creation of an exact 3D model and final assembly of all functional parts. The functional idea of the setup is based on a previously designed device that was used to perform more simple tasks. A series of experiments revealed certain disadvantages of the initial setup, for which pertinent solutions were found and implemented. Processing and correction of the data obtained from the device are demonstrated with an example involving backlash and signal drift errors. Correction of both linear and non-linear signal drift errors is considered. We also show that, depending on the research interests, the developed equipment can be further modified by alternating its peripheral parts without changing the main frame of the device.


Subject(s)
Adhesives
16.
Ultrasound Obstet Gynecol ; 61(2): 231-242, 2023 02.
Article in English | MEDLINE | ID: mdl-36178788

ABSTRACT

OBJECTIVE: Previous work has suggested that the ultrasound-based benign simple descriptors (BDs) can reliably exclude malignancy in a large proportion of women presenting with an adnexal mass. This study aimed to validate a modified version of the BDs and to validate a two-step strategy to estimate the risk of malignancy, in which the modified BDs are followed by the Assessment of Different NEoplasias in the adneXa (ADNEX) model if modified BDs do not apply. METHODS: This was a retrospective analysis using data from the 2-year interim analysis of the International Ovarian Tumor Analysis (IOTA) Phase-5 study, in which consecutive patients with at least one adnexal mass were recruited irrespective of subsequent management (conservative or surgery). The main outcome was classification of tumors as benign or malignant, based on histology or on clinical and ultrasound information during 1 year of follow-up. Multiple imputation was used when outcome based on follow-up was uncertain according to predefined criteria. RESULTS: A total of 8519 patients were recruited at 36 centers between 2012 and 2015. We excluded patients who were already in follow-up at recruitment and all patients from 19 centers that did not fulfil our criteria for good-quality surgical and follow-up data, leaving 4905 patients across 17 centers for statistical analysis. Overall, 3441 (70%) tumors were benign, 978 (20%) malignant and 486 (10%) uncertain. The modified BDs were applicable in 1798/4905 (37%) tumors, of which 1786 (99.3%) were benign. The two-step strategy based on ADNEX without CA125 had an area under the receiver-operating-characteristics curve (AUC) of 0.94 (95% CI, 0.92-0.96). The risk of malignancy was slightly underestimated, but calibration varied between centers. A sensitivity analysis in which we expanded the definition of uncertain outcome resulted in 1419 (29%) tumors with uncertain outcome and an AUC of the two-step strategy without CA125 of 0.93 (95% CI, 0.91-0.95). CONCLUSION: A large proportion of adnexal masses can be classified as benign by the modified BDs. For the remaining masses, the ADNEX model can be used to estimate the risk of malignancy. This two-step strategy is convenient for clinical use. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Adnexal Diseases , Ovarian Neoplasms , Female , Humans , Retrospective Studies , Ovarian Neoplasms/pathology , Adnexal Diseases/pathology , Ultrasonography/methods , CA-125 Antigen , Sensitivity and Specificity , Diagnosis, Differential
17.
Micromachines (Basel) ; 13(7)2022 Jul 19.
Article in English | MEDLINE | ID: mdl-35888958

ABSTRACT

Serious tool wear occurs very often during machining due to the reinforcing phases in the workpiece. In this study, micro-pit-textures were prepared on the surfaces of PCD tools with a nanosecond laser to improve their cutting performance on SiCp/Al composites. The micro-pits were designed with rounded corners to improve the chip flow. The location and size of the texture were determined by analyzing the tool-chip contact area of the non-textured tool. The cutting performance of these textured PCD tools was investigated through orthogonal cutting experiments. It was found that the optimal cutting performance of the textured tools was achieved with the proper distance of the texture from the main cutting edge (35 µm) and the pit spacing (60 µm), aa a result of which the main cutting force reduced by about 14%, and the tool wear and surface adhesion significantly reduced. This texture was then applied in the micro-turning experiments of the PCD tool on the SiCp/Al composites. The cutting force in this experiment reduced by 22%, and the textured tool provided better chip transfer and tool anti-tipping. In this study, the role of SiC particles as a third body between the tool and the chip surface is discussed.

18.
Ultrasound Obstet Gynecol ; 60(2): 243-255, 2022 08.
Article in English | MEDLINE | ID: mdl-35385178

ABSTRACT

OBJECTIVES: The primary aim of this study was to describe the ultrasound features of various endometrial and other intracavitary pathologies in women without abnormal uterine bleeding (AUB) using the International Endometrial Tumor Analysis (IETA) terminology. The secondary aim was to compare our findings with published data on women with AUB. METHODS: This was a prospective observational study of women presenting at one of seven centers specialized in gynecological ultrasonography, from 2011 until 2018, for indications unrelated to AUB. All patients underwent transvaginal ultrasound using the IETA examination and measurement techniques. Ultrasonography was performed as part of routine gynecological examination or follow-up of non-endometrial pathology, or as part of the work-up before undergoing treatment for infertility, uterine prolapse or ovarian pathology. Ultrasound findings were described using the IETA terminology. Endometrial sampling was performed after the ultrasound scan. The histological endpoints were endometrial atrophy, proliferative or secretory endometrium, endometrial hyperplasia without atypia, endometrial polyp, intracavitary leiomyoma, endometrial intraepithelial neoplasia (EIN), endometrial cancer (EC) and insufficient tissue. The findings in our cohort of women without AUB were compared with those in a published cohort of women with AUB who were examined with transvaginal ultrasound between 2012 and 2015 using the same IETA examination technique and terminology. RESULTS: In this study (IETA3), we included 1745 women without AUB who underwent a standardized transvaginal ultrasound examination followed by either endometrial sampling with histological diagnosis (n = 1537) or at least 1 year of clinical and ultrasound follow-up (n = 208). Of these, 858 (49.2%) women were premenopausal and 887 (50.8%) were postmenopausal. Histology showed the presence of EC and/or EIN in 29 (1.7%) women, endometrial polyps in 1028 (58.9%), intracavitary myomas in 66 (3.8%), proliferative or secretory changes or hyperplasia without atypia in 144 (8.3%), endometrial atrophy in 265 (15.2%) and insufficient tissue in five (0.3%). Most cases of EC or EIN (25/29 (86.2%)) were diagnosed after menopause. The mean endometrial thickness in women with EC or EIN was 11.2 mm (95% CI, 8.9-13.6 mm), being on average 2.4 mm (95% CI, 0.3-4.6 mm) thicker than their benign counterparts. Women with malignant endometrial pathology manifested more frequently non-uniform echogenicity (22/29 (75.9%)) than did those with benign endometrial pathology (929/1716 (54.1%)) (difference, +21.8% (95% CI, +4.2% to +39.2%)). Moderate to abundant vascularization (color score 3-4) was seen in 31.0% (9/29) of cases with EC or EIN compared with 12.8% (220/1716) of those with a benign outcome (difference, +18.2% (95% CI, -0.5% to +36.9%)). Multiple multifocal vessels were recorded in 24.1% (7/29) women with EC or EIN vs 4.0% (68/1716) of those with a benign outcome (difference, +20.2% (95% CI, +4.6% to +35.7%)). A regular endometrial-myometrial junction was seen less frequently in women with EC or EIN (19/29 (65.5%)) vs those with a benign outcome (1412/1716 (82.3%)) (difference, -16.8% (95% CI, -34.2% to +0.6%)). In women with endometrial polyps without AUB, a single dominant vessel was the most frequent vascular pattern (666/1028 (64.8%)). In women with EC, both in those with and those without AUB, the endometrium usually manifested heterogeneous echogenicity, but the endometrium was on average 8.6 mm (95% CI, 5.2-12.0 mm) thinner and less intensely vascularized (color score 3-4: difference, -26.8% (95% CI, -52.2% to -1.3%)) in women without compared to those with AUB. In both pre- and postmenopausal women, asymptomatic endometrial polyps were associated with a thinner endometrium, and they manifested more frequently a bright edge, a regular endometrial-myometrial junction and a single dominant vessel than did polyps in symptomatic women, and they were less intensely vascularized. CONCLUSIONS: We describe the typical ultrasound features of EC, polyps and other intracavitary histologies using IETA terminology in women without AUB. Our findings suggest that the presence of asymptomatic polyps or endometrial malignancy may be accompanied by thinner and less intensely vascularized endometria than their symptomatic counterparts. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Endometrial Hyperplasia , Endometrial Neoplasms , Polyps , Uterine Diseases , Uterine Neoplasms , Atrophy/pathology , Endometrial Hyperplasia/pathology , Endometrial Neoplasms/diagnostic imaging , Endometrial Neoplasms/pathology , Endometrium/diagnostic imaging , Endometrium/pathology , Female , Humans , Male , Polyps/diagnostic imaging , Polyps/pathology , Ultrasonography , Uterine Diseases/pathology , Uterine Hemorrhage/diagnostic imaging , Uterine Hemorrhage/etiology , Uterine Hemorrhage/pathology , Uterine Neoplasms/diagnostic imaging , Uterine Neoplasms/pathology
19.
Ultrasound Obstet Gynecol ; 60(4): 549-558, 2022 10.
Article in English | MEDLINE | ID: mdl-35316568

ABSTRACT

OBJECTIVE: To describe the clinical and ultrasound features of ovarian mature cystic teratomas (MCTs). METHODS: This was a retrospective study. From the International Ovarian Tumor Analysis (IOTA) database, we identified patients with a histologically confirmed diagnosis of MCT who had undergone transvaginal ultrasound examination between 1999 and 2016 (IOTA phases 1, 2, 3 and 5) in one of five centers. Ultrasound was performed by an experienced examiner who used the standardized IOTA examination technique and terminology. In addition to extracting data from the IOTA database, available two-dimensional grayscale and color or power Doppler images were reviewed retrospectively to identify typical ultrasound features of MCT described previously and detect possible new features using pattern recognition. All images were reviewed by two independent examiners and further discussed with two ultrasound experts to reach consensus. RESULTS: Included in the study were 454 patients with histologically confirmed MCT. Median age was 33 (range, 8-90) years and 66 (14.5%) patients were postmenopausal. Most MCTs were described by the original ultrasound examiner as unilocular (262/454 (57.7%)) or multilocular (70/454 (15.4%)) cysts with mixed echogenicity of cystic fluid (368/454 (81.1%)), acoustic shadowing (328/454 (72.2%)) and no or little vascularization on color Doppler (color score 1, 240/454 (52.9%); color score 2, 123/454 (27.1%)). The median largest lesion diameter was 66 (range, 15-310) mm. A correct preoperative diagnosis of MCT was suggested by the original ultrasound examiner in 372/454 (81.9%) cases. On retrospective review of ultrasound images of 334 MCTs that had quality sufficient for assessment, 'dots and/or lines' and/or 'echogenic white ball' (typical features according to the literature) were present in 271/334 (81.1%) masses. We identified four new ultrasound features characteristic of MCT: 'cotton wool tufts', 'mushroom cap sign', 'completely hyperechogenic lesion' and 'starry sky sign'. At least one classical or novel ultrasound feature was present in 315/334 (94.3%) MCTs. Twenty-nine (8.7%) MCTs manifested vascularized solid tissue, of which seven exhibited no typical features. CONCLUSION: We provide a comprehensive overview of conventional and newly described ultrasound features of MCTs. Only a small proportion of MCTs did not manifest any of the typical features. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Genital Diseases, Female , Ovarian Neoplasms , Teratoma , Adult , Female , Humans , Ovarian Neoplasms/pathology , Pregnancy , Retrospective Studies , Teratoma/diagnostic imaging , Ultrasonography , Ultrasonography, Doppler, Color/methods
20.
PLoS One ; 17(3): e0265237, 2022.
Article in English | MEDLINE | ID: mdl-35298510

ABSTRACT

Hypselodont (ever-growing) teeth of lagomorphs or rodents have higher wear rates (of a magnitude of mm/week), with compensating growth rates, compared to the non-ever-growing teeth of ungulates (with a magnitude of mm/year). Whether this is due to a fundamental difference in enamel hardness has not been investigated so far. We prepared enamel samples (n = 120 per species) from incisors of cattle (Bos primigenius taurus) and nutria (Myocastor coypus, hypselodont incisors) taken at slaughterhouses, and submitted them to indentation hardness testing. Subsequently, samples were split into 4 groups per species (n = 24 per species and group) that were assessed for abrasion susceptibility by a standardized brush test with a control (no added abrasives) and three treatment groups (using fine silt at 4 ±1 µm particle size, volcanic ash at 96 ±9 µm, or fine sand at 166 ±15 µm as abrasives), in which enamel abrasion was quantified as height loss by before-and-after profilometry. The difference in enamel hardness between the species was highly significant, with nutria enamel achieving 78% of the hardness of cattle enamel. In the control and the fine sand group, no enamel height loss was evident, which was attributed to the in vitro system in the latter group, where the sand particles were brushed out of the test slurry by the brushes' bristles. For fine silt and volcanic ash, nutria enamel significantly lost 3.65 and 3.52 times more height than cattle. These results suggest a relationship between enamel hardness and susceptibility to abrasion. However, neither the pattern within the species nor across the species indicated a monotonous relationship between hardness and height loss; rather, the difference was due to qualitative step related to species. Hence, additional factors not measured in this study must be responsible for the differences in the enamel's susceptibility to abrasion. While the in vitro brush system cannot be used to rank abrasive test substances in terms of their abrasiveness, it can differentiate abrasion susceptibility in dental tissue of different animal species. The results caution against considering enamel wear as a similar process across mammals.


Subject(s)
Tooth Abrasion , Tooth Erosion , Animals , Cattle , Dental Enamel , Hardness , Incisor , Mammals , Sand , Toothbrushing
SELECTION OF CITATIONS
SEARCH DETAIL
...