Tripod Type Research Articles

A comparison of machine learning models for predicting urinary incontinence in men with localized prostate cancer.

Urinary incontinence (UI) is a common side effect of prostate cancer treatment, but in clinical practice, it is difficult to predict. Machine learning (ML) models have shown promising results in predicting outcomes, yet the lack of transparency in complex models known as "black-box" has made clinicians wary of relying on them in sensitive decisions. Therefore, finding a balance between accuracy and explainability is crucial for the implementation of ML models. The aim of this study was to employ three different ML classifiers to predict the probability of experiencing UI in men with localized prostate cancer 1-year and 2-year after treatment and compare their accuracy and explainability. We used the ProZIB dataset from the Netherlands Comprehensive Cancer Organization (Integraal Kankercentrum Nederland; IKNL) which contained clinical, demographic, and PROM data of 964 patients from 65 Dutch hospitals. Logistic Regression (LR), Random Forest (RF), and Support Vector Machine (SVM) algorithms were applied to predict (in)continence after prostate cancer treatment. All models have been externally validated according to the TRIPOD Type 3 guidelines and their performance was assessed by accuracy, sensitivity, specificity, and AUC. While all three models demonstrated similar performance, LR showed slightly better accuracy than RF and SVM in predicting the risk of UI one year after prostate cancer treatment, achieving an accuracy of 0.75, a sensitivity of 0.82, and an AUC of 0.79. All models for the 2-year outcome performed poorly in the validation set, with an accuracy of 0.6 for LR, 0.65 for RF, and 0.54 for SVM. The outcomes of our study demonstrate the promise of using non-black box models, such as LR, to assist clinicians in recognizing high-risk patients and making informed treatment choices. The coefficients of the LR model show the importance of each feature in predicting results, and the generated nomogram provides an accessible illustration of how each feature impacts the predicted outcome. Additionally, the model's simplicity and interpretability make it a more appropriate option in scenarios where comprehending the model's predictions is essential.

Open Source Repository and Online Calculator of Prediction Models for Diagnosis and Prognosis in Oncology.

(1) Background: The main aim was to develop a prototype application that would serve as an open-source repository for a curated subset of predictive and prognostic models regarding oncology, and provide a user-friendly interface for the included models to allow online calculation. The focus of the application is on providing physicians and health professionals with patient-specific information regarding treatment plans, survival rates, and side effects for different expected treatments. (2) Methods: The primarily used models were the ones developed by our research group in the past. This selection was completed by a number of models, addressing the same cancer types but focusing on other outcomes that were selected based on a literature search in PubMed and Medline databases. All selected models were publicly available and had been validated TRIPOD (Transparent Reporting of studies on prediction models for Individual Prognosis Or Diagnosis) type 3 or 2b. (3) Results: The open source repository currently incorporates 18 models from different research groups, evaluated on datasets from different countries. Model types included logistic regression, Cox regression, and recursive partition analysis (decision trees). (4) Conclusions: An application was developed to enable physicians to complement their clinical judgment with user-friendly patient-specific predictions using models that have received internal/external validation. Additionally, this platform enables researchers to display their work, enhancing the use and exposure of their models.

Radiomics models for preoperative prediction of microvascular invasion in hepatocellular carcinoma: a systematic review and meta-analysis.

To assess the methodological quality and to evaluate the predictive performance of radiomics studies for preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Publications between 2017 and 2021 on radiomic MVI prediction in HCC based on CT, MR, ultrasound, and PET/CT were included. The risk of bias was assessed using the prediction model risk of bias assessment tool (PROBAST). Methodological quality was assessed through the radiomics quality score (RQS). Fourteen studies classified as TRIPOD Type 2a or above were used for meta-analysis using random-effects model. Further analyses were performed to investigate the technical factors influencing the predictive performance of radiomics models. Twenty-three studies including 4947 patients were included. The risk of bias was mainly related to analysis domain. The RQS reached an average of (37.7 ± 11.4)% with main methodological insufficiencies of scientific study design, external validation, and open science. The pooled areas under the receiver operating curve (AUC) were 0.85 (95% CI 0.82-0.89), 0.87 (95% CI 0.83-0.92), and 0.74 (95% CI 0.67-0.80), respectively, for CT, MR, and ultrasound radiomics models. The pooled AUC of ultrasound radiomics model was significantly lower than that of CT (p = 0.002) and MR (p < 0.001). Portal venous phase for CT and hepatobiliary phase for MR were superior to other imaging sequences for radiomic MVI prediction. Segmentation of both tumor and peritumor regions showed better performance than tumor region. Radiomics models show promising prediction performance for predicting MVI in HCC. However, improvements in standardization of methodology are required for feasibility confirmation and clinical translation.

Covid19Risk.ai: An Open Source Repository and Online Calculator of Prediction Models for Early Diagnosis and Prognosis of Covid-19

Background: The current pandemic has led to a proliferation of predictive models being developed to address various aspects of COVID-19 patient care. We aimed to develop an online platform that would serve as an open source repository for a curated subset of such models, and provide a simple interface for included models to allow for online calculation. This platform would support doctors during decision-making regarding diagnoses, prognoses, and follow-up of COVID-19 patients, expediting the models’ transition from research to clinical practice. Methods: In this pilot study, we performed a literature search in the PubMed and WHO databases to find suitable models for implementation on our platform. All selected models were publicly available (peer reviewed publications or open source repository) and had been validated (TRIPOD type 3 or 2b). We created a method for obtaining the regression coefficients if only the nomogram was available in the original publication. All predictive models were transcribed on a practical graphical user interface using PHP 8.0.0, and were published online together with supporting documentation and links to the associated articles. Results: The open source website currently incorporates nine models from six different research groups, evaluated on datasets from different countries. The website will continue to be populated with other models related to COVID-19 prediction as these become available. This dynamic platform allows COVID-19 researchers to contact us to have their model curated and included on our website, thereby increasing the reach and real-world impact of their work. Conclusion: We have successfully demonstrated in this pilot study that our website provides an inclusive platform for predictive models related to COVID-19. It enables doctors to supplement their judgment with patient-specific predictions from externally validated models in a user-friendly format. Additionally, this platform supports researchers in showcasing their work, which will increase the visibility and use of their models.

Spatial focusing of surface polaritons based on cross-phase modulation

We theoretically study the spatial focusing of surface polaritons (SPs) in a negative index metamaterial-atomic gas interface waveguide system, based on cross phase modulation (XPM) in a tripod type double electromagnetically induced transparency (EIT) scheme. In the linear region, we realize the low-loss stable propagation of SPs, and the group velocities of the probe and signal fields are well matched via double EIT. In the nonlinear region, we show that giant enhancement of the XPM can be obtained. Using a narrow optical soliton in free space, we realize spatial focusing of the SPs solitons, including bright, multi bright, and gray solitons. The full width at the half-maximum of the SPs soliton can be compressed to about ten nanometers, thus, even nanofocusing can be obtained. The results obtained her e have certain theoretical significance for nano-scale sensing, spectral enhancement and precision measurement.

Synthesis of a tertiary amine by direct reductive amination of a carbonyl compound to form a scorpionate ligand; formation of Mn (II), Zn (II) and Cd (II) complexes, DFT calculations and, molecular docking studies

A hexadentate, asymmetric tripodal scorpionate type ligand, [[N1-Pyridin-2-ylmethyl-N1-[2-(4-pyridine-2-ylmethyl-piperazine-1-yl)-ethyl]-ethane-1,2-diamine]] (L) has been prepared. To form this ligand, the direct reductive amination of a carbonyl compound by NaBH4 was used for the synthesis of tertiary amine. The complexes [MnL])ClO4(2, [CdL])ClO4(2, [ZnL])ClO4(2 have also been prepared. The synthesized compounds were characterized by elemental analyses, FT-IR, ESI-MS and, NMR spectroscopy. An X-ray crystal structure of [MnL] (ClO4)2, shows that the coordination environment around the manganese is a distorted trigonal prism. The nature of metal–ligand bonding in the complexes was investigated by Natural Bond Orbital analysis, Energy Decomposition Analysis and Energy Decomposition Analysis using Natural Orbitals for Chemical Valence variation. Molecular docking has been used for the biological evaluation of the anticancer and antioxidant activities of the synthesized compounds. The docking results indicated that the Cd, Mn, and Zn-complexes had the highest binding affinity (MolDock Score) for the binding sites of cytochrome P450, myeloperoxidase, and cytochrome P450, respectively.

Value of 18F-FDG PET/CT radiomic features to distinguish solitary lung adenocarcinoma from tuberculosis.

To develop a predictive model by 18F-FDG PET/CT radiomic features and to validate the predictive value of the model for distinguishing solitary lung adenocarcinoma from tuberculosis. A total of 235 18F-FDG PET/CT patients with pathologically or follow-up confirmed lung adenocarcinoma (n = 131) or tuberculosis (n = 104) were retrospectively and randomly divided into a training (n = 163) and validation (n = 72) cohort. Based on the Transparent Reporting of Multivariable Prediction Model for Individual Prognosis or Diagnosis (TRIPOD), this work was belonged to TRIPOD type 2a study. The Mann-Whitney U test and least absolute shrinkage and selection operator (LASSO) algorithm were used to select the optimal predictors from 92 radiomic features that were extracted from PET/CT, and the optimal predictors were used to build the radiomic model in the training cohort. The meaningful clinical variables comprised the clinical model, and the combination of the radiomic model and clinical model was a complex model. The performances of the models were assessed by the area under the receiver operating characteristic curve (AUC) in the training and validation cohorts. In the training cohort, 9 radiomic features were selected as optimal predictors to build the radiomic model. The AUC of the radiomic model was significantly higher than that of the clinical model in the training cohort (0.861 versus 0.686, p < 0.01), and this was similar in the validation cohort (0.889 versus 0.644, p < 0.01). The AUC of the radiomic model was slightly lower than that of the complex model in the training cohort (0.861 versus 0.884, p > 0.05) and validation cohort (0.889 versus 0.909, p > 0.05), but there was no significant difference. 18F-FDG PET/CT radiomic features have a significant value in differentiating solitary lung adenocarcinoma from tuberculosis.

Kinematic analysis of a new 3-PRRS tripod type parallel manipulator

Kinematic analysis of a new 3-PRRS tripod type parallel manipulator

External Validation of Radiation-Induced Dyspnea Models on Esophageal Cancer Radiotherapy Patients.

Purpose: Radiation-induced lung disease (RILD), defined as dyspnea in this study, is a risk for patients receiving high-dose thoracic irradiation. This study is a TRIPOD (Transparent Reporting of A Multivariable Prediction Model for Individual Prognosis or Diagnosis) Type 4 validation of previously-published dyspnea models via secondary analysis of esophageal cancer SCOPE1 trial data. We quantify the predictive performance of these two models for predicting the maximal dyspnea grade ≥ 2 within 6 months after the end of high-dose chemo-radiotherapy for primary esophageal cancer.Materials and methods: We tested the performance of two previously published dyspnea risk models using baseline, treatment and follow-up data on 258 esophageal cancer patients in the UK enrolled into the SCOPE1 multi-center trial. The tested models were developed from lung cancer patients treated at MAASTRO Clinic (The Netherlands) from the period 2002 to 2011. The adverse event of interest was dyspnea ≥ Grade 2 (CTCAE v3) within 6 months after the end of radiotherapy. As some variables were missing randomly and cannot be imputed, 212 patients in the SCOPE1 were used for validation of model 1 and 255 patients were used for validation of model 2. The model parameter Forced Expiratory Volume in 1 s (FEV1), as a predictor to both validated models, was imputed using the WHO performance status. External validation was performed using an automated, decentralized approach, without exchange of individual patient data.Results: Out of 258 patients with esophageal cancer in SCOPE1 trial data, 38 patients (14.7%) developed radiation-induced dyspnea (≥ Grade 2) within 6 months after chemo-radiotherapy. The discrimination performance of the models in esophageal cancer patients treated with high-dose external beam radiotherapy was moderate, area under curve (AUC) of 0.68 (95% CI 0.55–0.76) and 0.70 (95% CI 0.58–0.77), respectively. The curves and AUCs derived by distributed learning were identical to the results from validation on a local host.Conclusion: We have externally validated previously published dyspnea models using an esophageal cancer dataset. FEV1 that is not routinely measured for esophageal cancer was imputed using WHO performance status. Prediction performance was not statistically different from previous training and validation sets. Risk estimates were dominated by WHO score in Model 1 and baseline dyspnea in Model 2. The distributed learning approach gave the same answer as local processing, and could be performed without accessing a validation site's individual patients-level data.

Syntheses, structure and properties of dinuclear Co complexes with bis(catecholate) ligands – Effect of a quinoline ring in the terminal group

Two types of biscatechol, namely H4L1 (5,5′-(buta-1,3-diyne-1,4-diyl)bis(3-t-butylcatechol)) and H4L2 (5,5′-(ethyne-1,2-diyl)bis(3-t-butylcatechol)) were synthesized. In these ligands, two redox active catechol moieties are connected by one or two triple bonds. Also, tpa (tris(2-pyridylmethyl) amine), bpqa (bis(2-pyridylmethyl)(2-quinolylmethyl)amine) and pbqa ((2-pyridylmethyl)bis(2-quinolylmethyl)amine) were synthesized as terminal ligands of the tetracoordinated tripod type. In total, six dinuclear Co complexes were synthesized from these biscatechol and terminal ligands as follows: [Co2(L1)(tpa)2](BF4)2 (1), [Co2(L1)(bpqa)2](PF6)2 (2), [Co2(L1)(pbqa)2](PF6)2 (3), [Co2(L2)(tpa)2](BF4)2 (4), [Co2(L2)(bpqa)2](PF6)2 (5), [Co2(L2)(pbqa)2](PF6)2 (6). Of the six dinuclear Co complexes, complex 6, which was isolated as a mixed valent state CoII(HS)-[SQ-Cat]-CoIII(LS) compound, showed an absorption intensity at around 703 nm (MLCT bands) that increased with increasing temperature in acetonitrile solution. In addition, an investigation of the magnetic properties of the complex 6 with SQUID showed that the χMT value gradually increased as the temperature increased from 150 to 380 K. This suggests that a transition from CoIII(LS) (S = 0) to CoII(HS) (S = 3/2) accompanies the temperature rise. This means the steric hindrance and electronic effect of the quinolyl groups around the Co ion produce a coordination atmosphere weaker than that of pyridyl groups, with the result that the CoIII ions easily convert to CoII ions.

Extraction of scandium and other rare earth elements with a tricarboxylic acid derivative of tripodal pseudcalix[3]arene prepared from a new phenolic tripodal framework

We prepared a phenolic tripodal type extraction reagent to investigate the extraction of a series of rare earth metal ions. The extraction reaction and equilibrium extraction constants for rare earth ions with the tripodal extractant were evaluated using slope analysis and Job’s method. The tripodal reagent exhibited remarkably high extraction ability compared with a corresponding monopodal compound, and exhibited different extraction selectivities for rare earth metal ions than a calix[4]arene derivative because of the different size of the coordination site. The developed phenolic tripodal extraction reagent provides a new framework with a different size coordination site to those in calix[4]arene and alkyltrimethylol type tripodal compounds.

A real time wear measurement system for tripod type constant velocity joints

A real-time wear measurement system for tripod type Constant Velocity (CV) joints is proposed in this study. Adhesive wear on tripod type CV joints is very crucial to the life time of CV joints but it is very difficult to measure the wear depth of a tripod type CV joint separate from the drive shaft assembly. The wear measurement system developed in this study can measure the wear depth of a tripod type CV joint in real-time as it applies kinematics and forces to the CV joint.In order to apply the same motions as the motions of an actual CV joint, kinematics of the CV joint has been analyzed. As a result, reciprocating stroke and yaw motions have been completely implemented in the system. The wear measurement system comprises four parts. The first part is for applying normal forces to a set of spherical roller and housing track. One servo motor, spur gear and ball screw sets were employed to generate and augment the normal forces. The second and third parts are for applying reciprocating stroke and yaw motions, respectively. These parts synchronize with each other to make the same motion profiles as the actual CV joint. The fourth part is for measurement. This part consists of load cell and rotary encoder to measure the surge normal forces caused by the flaking phenomena and the wear depth caused by the adhesive wear. In the case of the encoder, the wear depth is augmented by the ball screw and spur gear sets so 0.18°/μm of measurement resolution can be achieved.For the validation of the system, a tripod type CV joint was selected, and its wear depth was measured by the system and the results were compared with the wear depth measured by a profilometer.

A new life model of tripod type Constant Velocity Joint using accelerated life test

Abstract This study proposes a new wear life model, focusing on the adhesive wear phenomena that occur in tripod type CVJs. For the development of the wear life model, kinematic analysis was performed to derive the relative coordinates of components and contact points. Then, the normal pressure at the contact points were calculated. In order to investigate the wear amount of each contact point, an Accelerated Life Testing (ALT) based on a reliability analysis theory was employed. In this study, a new experimental system was built to experiment the wear of CVJ components, which enables to measure the wear amount under much harsher conditions than actual driving conditions. The experimental results from the ALT were analyzed and organized for the wear life model. Finally, the developed model was verified by comparing the estimated results with the experimental results under an actual driving condition.

Study on the friction in the tripod type couplings with external contacts

One of the basic criteria which is influencing the choosing process of a tripod coupling in a mechanical transmission is the friction. Due to their, construction the elements being in contact between the driver and the driven elements, are suppose to be optimized; this optimization it could be according to the shape or/and according to the materials. In the paper there are performed tests for the case of the line type contacts between the driver and the driven elements, in analogy with the tripod coupling with the cylinder on cylinder contacts. There are studied two cases: steel pin on steel disk and steel pin on PA66 polyamide type contacts. The test are performed for a set of rotational speeds of 500, 1000, 2000 and 3000 rpm and a set of normal forces as 3, 5, 7 and 9 N, in non-lubricated conditions. There are identified conclusions regarding the friction coefficient evolution and values in the case of steel on steel and steel on PA66 polyamide type contacts.

Study on the loading capacity of the tripod type couplings with external contacts

The paper presents the study of the contact pressure of the tripod couplings with external contacts, in order to identify the geometries of the contact elements which assure higher loading capacities. The article starts with the study of the literature; there are identified the main conclusions regarding the loading capacity, the life time and the forces which are acting between the elements. For the geometrical modelling of the tripod coupling with external contacts there are considered three variants for the shape of the elements which are in contact: cylinder on cylinder, parabolic on parabolic and hyperbolic on hyperbolic. The pressure contacts are determined by achieving a finite element analysis for all the geometric variants. The finite element analyses is performed for a set of values for the contact force as 100 N, 200 N, 300 N, 400 N and a set of values for the angle between the input and the output shaft as 0°, 10°, 20°, 30°. Finally there are identified conclusions regarding the variation of the contact pressure with the applied normal force and with the angle between shafts; it is identified the variant of the contact geometry which assure the highest loading capacity.

Evaluation of influence on shape design of floating offshore wind turbine substructures

The increase of demand and the depletion of energy resources have led to a rising demand of renewable energy. Among them, wind turbine has been researched because of wide generality with high resource potential. Despite these advantages, onshore wind turbine has a spatial constraint. To solve these problems, offshore wind turbine has been researched and the installation area of onshore structures has been expanded to offshore field. The design of the substructure is one of the most important issues in case of motion characteristics in the ocean rather than on the coast. Tri-pod type is attracting attention because it is easy to manufacture and efficient to reduce environmental load. However, the motion characteristics of these types of structures have not been clarified yet and are currently studied. In order to improve the float performance, it is necessary to apply the optimal float design such as size, weight, water plane area, and mooring to each design. In this study, we have described tri-pod type model and evaluated the model test to find the effects of the ratio of the diameter to draft in dynamic motions of the structures on the basis of the floating column design. Since each design variables are determined, experimental RAO results have analysed through motion analysis of 6 degrees of freedom.

Motion analysis of a six-legged robot using Bennett's linkage as leg

ABSTRACTAlthough legged robots are considered as the most versatile type of robot due to their major capability of moving on uneven terrain, the robots which have been studied do not have much mobility. In general, this lack of mobility is related to the high number of degrees of freedom that makes it difficult to solve their mathematical model and to apply it to the control system. This problem gives them a low operational speed. It was not possible to solve this problem on mobile robots whose legs are based on parallel structures either. One alternative is to use simpler mechanisms, obtaining a small number of degrees of freedom for the legs. The solution that is analyzed in this article uses Bennett's linkage for a six legged robot. From the kinematic analysis of each leg, the robot motion is analyzed for two kinds of movements: the tripod type and the tetrapod type. In the present work, the kinematic analysis of the robot's behavior is examined in order to know in advance what can occur to the robot when it walks. After the analysis, some studies to make the robot able to move smoothly are proposed, even considering its dynamics.

Synthesis and Properties of Novel Tripod Type Multi-benzimidazole Quaternary Ammonium Compounds

Synthesis and Properties of Novel Tripod Type Multi-benzimidazole Quaternary Ammonium Compounds

Electro- and photocatalytic hydrogen evolution by a cobalt complex based on a tripodal iminopyridine ligand

A cobalt complex based on the tripodal iminopyridine type ligand (2E)-2-N-(pyridin-2-ylmethylidene)-1-N,1-N-bis({2-[(E)-(pyridin-2-ylmethylidene)amino]phenyl})benzene-1,2-diamine (L1), namely, [CoL1](BF4)2 (1a), was synthesized and characterized by FT-IR, UV–Vis spectroscopy, magnetic moment and elemental analysis. X-ray structural study of 1a shows that the complex is coordinatively saturated and contains the uncoordinated bridgehead nitrogen atom. Electrochemical studies reveal that the complex 1a has an electrocatalytic proton reduction activity in acetonitrile, when using acetic acid as a proton source with icat/ip∼3.3. Therefore we estimate that the complex 1a could give the highest TOF of 2.3s−1 for the reduction of proton to hydrogen. Furthermore, under visible-light irradiation, an optimized H2 evolution system containing 1a (0.1mM), [Ir(ppy)2(bpy)](PF6) (0.1mM), and 10vol% TEA in CH3CN–H2O (1/1, v/v) mixed solvents at pH 10 gives a highest turnover number of 34. For comparison, an electron-withdrawing ester group (CO2CH2CH3) is introduced into the pyridine moiety of the ligand as in L2, however, which leads to its corresponding cobalt complex 2a less active than the complex 1a for electro- and photocatalytic H2 evolution. Additionally, the control experiment establishes that the isostructural zinc complex [ZnL1](BF4)2 (1b) is ineffective for H2 generation.

Not only “nurture”, but also “nature”, influence the outcome of zygoma repair

The present study aims to elucidate the relationship between preoperative deviation patterns of fractured zygomas and treatment outcomes. Forty-five randomly selected patients with tri-pod type zygoma fractures were classified into a medial rotation group and a lateral rotation group, depending on preoperative deviation patterns. A minimum of 6 months after the operation, symmetry of the cheek was evaluated by three plastic surgeons using a VAS system. The evaluated scores were compared between the two groups. Furthermore, simulation of postoperative secondary deformity was performed by applying hypothetically defined relapse forces on CAD models produced by referring to the CT data of 20 patients. The deviation values obtained by the simulation were compared between the two groups. The results demonstrate that VAS scores were higher for the lateral rotation group than for the medial rotation group and that the deviation values were higher for the medial rotation group than for the lateral rotation group. It is concluded that treatment outcomes of zygoma fractures are affected by preoperative deviation patterns. Cases with medial rotation are likely to present poorer outcomes than those with lateral rotation.