Corona Mortis: Surgical Anatomy, Physiology and Clinical Significance

Corona mortis (CM) is classically defined as the arterial anastomosis between the obturator artery and the inferior epigastric artery that crosses the posterior aspect of the superior ramus of the symphysis pubis. Its clinical impact is considered great, as it lies within the surgical field of numerous specialties (general surgeons, orthopedists, gynecologists, urologists). Our systematic study of the literature revealed a diversity in the incidence of the Corona Mortis between cadaveric and patient studies. The new technological advances and especially the CT angiography, applied on the retropubic region vessels, have given the chance to obtain more precise depictions and thus estimations on the real incidence of corona mortis. This review intends to extract for the first time the corona mortisrsquo incidence from the major CT angiographic studies in bibliography and compare it with the incidence of CM in the major cadaveric studies. Special attention was given to the question whether this anastomosis is that important as its name implies (mortis) in the clinical setting or not

Finite-Element Model for Pretensioned Prestressed Concrete Girders

This paper presents a nonlinear model for pretensioned prestressed concrete girders. The model consists of three main components: a beam-column element that describes the behavior of concrete, a truss element that describes the behavior of prestressing tendons, and a bond element that describes the transfer of stresses between the prestressing tendons and the concrete. The model is based on a two-field mixed formulation, where forces and deformations are both approximated within the element. The nonlinear response of the concrete and tendon components is based on the section discretization into fibers with uniaxial hysteretic material models. The stress transfer mechanism is modeled with a distributed interface element with special bond stress-slip relation. A method for accurately simulating the prestressing operation is presented. Accordingly, a complete nonlinear analysis is performed at the different stages of prestressing. Correlation studies of the proposed model with experimental results of pretensioned specimens are conducted. These studies confirmed the accuracy and efficiency of the model

Effect of polyamines and synthetic polyamine-analogues on the expression of the E. coli ato operon and its regulatory genes

AbstractJournal URL: http://www.eie.gr/iopc-costb22/index.htm

Understanding motivation for implementing cooperative learning methods: a value-based approach.

The implementation of cooperative learning methods remains disparate in primary schools despite their widely recognised benefits. To explain this paradox, we first examined whether teachers' inclination towards cooperative methods is motivated by their values. Second, we tested whether motivational connections between personal values and cooperative methods are undermined when conflictual values are activated in context. Study 1 demonstrated that pre-service teachers strongly endorsed self-transcendence (ST) values (expressing compatible motivations with cooperation) relative to self-enhancement (SE) values (expressing conflictual motivations with cooperation). Adherence to ST values was also positively associated with their beliefs and attitudes regarding cooperative methods. In Studies 2, 3 and 4, educational sciences students were experimentally exposed to different contexts, wherein ST, SE or neutral values were promoted. Our findings indicate that when SE values were emphasised in the context, the positive association between ST values and beliefs/attitudes regarding cooperative methods disappeared. Although the results of Study 4 regarding the intention to use cooperative methods were not statistically significant, the pattern was similar. Finally, Study 5 showed that primary school teachers' ST values positively predicted the self-reported use of cooperative methods when they perceived their school to weakly endorse SE values, but not when they perceived it to strongly endorse them

X-ray absorption spectroscopy systematics at the tungsten L-edge

A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, has been interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W<sup>0</sup>(PMe<sub>3</sub>)<sub>6</sub>], [W<sup>II</sup>Cl<sub>2</sub>(PMePh<sub>2</sub>)<sub>4</sub>], [W<sup>III</sup>Cl<sub>2</sub>(dppe)<sub>2</sub>][PF<sub>6</sub>] (dppe = 1,2-bis(diphenylphosphino)ethane), [W<sup>IV</sup>Cl<sub>4</sub>(PMePh<sub>2</sub>)<sub>2</sub>], [W<sup>V</sup>(NPh)Cl<sub>3</sub>(PMe<sub>3</sub>)<sub>2</sub>], and [W<sup>VI</sup>Cl<sub>6</sub>] correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio (EBR) of the L<sub>3,2</sub>-edges and the L<sub>1</sub> rising-edge energy with metal Z<sub>eff</sub>, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [W<sup>IV</sup>(mdt)<sub>2</sub>(CO)<sub>2</sub>] and [W<sup>IV</sup>(mdt)<sub>2</sub>(CN)<sub>2</sub>]<sup>2–</sup> (mdt<sup>2–</sup> = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively W<sup>IV</sup> species. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: 1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Z<sub>eff</sub> in the species of interest; 2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS; 3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal-ligand distances, exaggerate the difference between formal oxidation state and metal Z<sub>eff</sub> or, as in the case of [W<sup>IV</sup>(mdt)<sub>2</sub>(CO)<sub>2</sub>], add other subtlety by modulating the redox level of other ligands in the coordination sphere

Regression spline bivariate probit models: A practical approach to testing for exogeneity

Bivariate probit models can deal with a problem usually known as endogeneity. This issue is likely to arise in observational studies when confounders are unobserved. We are concerned with testing the hypothesis of exogeneity (or absence of endogeneity) when using regression spline recursive and sample selection bivariate probit models. Likelihood ratio and gradient tests are discussed in this context and their empirical properties investigated and compared with those of the Lagrange multiplier and Wald tests through a Monte Carlo study. The tests are illustrated using two datasets in which the hypothesis of exogeneity needs to be tested

Capturing accelerometer outputs in healthy volunteers under normal and simulated-pathological conditions using ML classifiers

Wearable devices offer a possible solution for acquiring objective measurements of physical activity. Most current algorithms are derived using data from healthy volunteers. It is unclear whether such algorithms are suitable in specific clinical scenarios, such as when an individual has altered gait. We hypothesized that algorithms trained on healthy population will result in less accurate results when tested in individuals with altered gait. We further hypothesized that algorithms trained on simulated-pathological gait would prove better at classifying abnormal activity.We studied healthy volunteers to assess whether activity classification accuracy differed for those with healthy and simulated-pathological conditions. Healthy participants (n=30) were recruited from the University of Leeds to perform nine predefined activities under healthy and simulated-pathological conditions. Activities were captured using a wrist-worn MOX accelerometer (Maastricht Instruments, NL). Data were analyzed based on the Activity-Recognition-Chain process. We trained a Neural-Network, Random-Forests, k-Nearest-Neighbors (k-NN), Support-Vector-Machines (SVM) and Naive Bayes models to classify activity. Algorithms were trained four times; once with 'healthy' data, and once with 'simulated-pathological data' for each of activity-type and activity-task classification. In activity-type instances, the SVM provided the best results; the accuracy was 98.4% when the algorithm was trained and then tested with unseen data from the same group of healthy individuals. Accuracy dropped to 52.8% when tested on simulated-pathological data. When the model was retrained with simulated-pathological data, prediction accuracy for the corresponding test set was 96.7%. Algorithms developed on healthy data are less accurate for pathological conditions. When evaluating pathological conditions, classifier algorithms developed using data from a target sub-population can restore accuracy to above 95%.Clinical Relevance - This method remotely establishes health-related data of objective outcome measures of activities of daily living

Gender Bias in Surgical Oncology Fellowship Recommendation Letters: Gaining Progress

OBJECTIVE: Gender bias has been identified in letters of recommendation (LOR) in many different surgical training fields. Among surgeons, women comprise over 30% of the full-time faculty positions nationally and surgical oncology is one of the most gender diverse surgical subspecialties. We sought to determine if bias existed in LOR submitted to a Complex General Surgical Oncology (CGSO) fellowship. DESIGN: LOR for the CGSO fellowship were retrospectively analyzed from applicants at a single institution over an 8-year period (2013-2020). The linguistic content of the letters was analyzed using Linguistic Inquiry and Word Count (LIWC2015), a validated text analysis program. Using multivariable analysis, LOR were compared by gender of both applicant and letter writer to explore the association between gender and the characteristics of the applicants and letter writers. SETTING: University of North Carolina at Chapel Hill (UNC), Division of Surgical Oncology and Endocrine Surgery. PARTICIPANTS: Applicants interviewed for the CSGO fellowship program at the UNC from 2013 to 2020 as well as all applicants from the 2018 application cycle, regardless of interview status. RESULTS: About 841 letters from 219 interviewed applicants throughout the 2013 to 2020 surgical oncology fellowship application cycles were included. No difference in authenticity, clout, analytic thinking, or emotional tone of the letters was seen when comparing men and women applicants. Of the 41 word categories analyzed, only "references to achievement" in LOR written for women was significantly higher when compared to LOR written for men (p = 0.01). Interestingly, significantly more women applicants had at least 1 LOR written by a woman (p = 0.04). A subset analysis of all applicants regardless of interview status from the 2018 cycle included 294 LOR from 77 applicants. With the inclusion of noninterviewed applicants, LOR for men had more analytic tone than LOR for women (p = 0.02), otherwise there were no significant differences between the groups. CONCLUSIONS: Very few differences in LOR were found for applicants at a CGSO fellowship program based on applicant or letter writer gender. The lack of gender bias demonstrates progress within the field of surgical oncology, likely a result of recent work and educational effort in this area. Efforts to expand this progress into other surgical sub-specialties are necessary

Vertebral artery variations revised: origin, course, branches and embryonic development

Background: The vertebral artery originates from the subclavian artery and is divided into four segments. The aim of this study is to investigate the anatomical variations in the course and branches of the vertebral artery. Materials and methods: A research was performed via PubMed database, using the terms: “variations of vertebral artery AND cadaveric study”, “variations of vertebral artery AND cadavers” and “anomalies of vertebral artery AND cadavers”. Results: A total of 24 articles met the inclusion criteria, 13 of them referring to variations of the origin of the vertebral artery, 9 to variations of the course and 3 to variations of its branches. On a total sample of 1192 cadavers of different populations, origin of the left vertebral artery directly from the aortic arch was observed at 6.7%. In addition, among 311 cadavers, 17.4% were found with partially or fully ossified foramen of the atlas for the passage of the vertebral artery, while the bibliographic review also showed variants at the exit site of the artery from the transverse foramen of the axis. Conclusions: Despite the fact that variations of both the course and the branches of vertebral artery are in most cases asymptomatic, good knowledge of anatomy and its variants is of particular importance for the prevention of vascular complications during surgical and radiological procedures in the cervix area