Mechanical Behavior of PET-G Tooth Aligners Under Cyclic Loading

Invisible aligners are medical devices, which allow repositioning of teeth through a treatment designed by the orthodontists. During this orthodontic treatment, patients use several aligners each for a couple of weeks. The aligner will apply a system of forces on the teeth to shift them to desired position. Since aligners exert forces thanks to their particular shape, it is important that during lifetime's service they do not undergo significant deformations. This research aims to study the mechanical behavior of invisible aligners made by polyethylene terephthalate-glycol (PET-G), which is one of most used the plastic materials to produce such devices. In this study, cyclic compression tests in atmospheric environment (∼25°C) as well as in the presence of saliva (to simulate intraoral environment) were performed. The mechanical behavior of aligners with two different thicknesses (0.75 and 0.88 mm) was studied. In particular, each aligner was subjected to 22500 load cycles from 0 to 50 N. The chosen number of load cycles simulates the average load history to which an aligner is subjected during its lifetime. The tests were performed on a testing machine, using a hard resin dental cast properly fixed to the machine. Analysis of the results shows that the stiffness of the aligners increases during the cyclic test. In particular, a gradual reduction of the crosshead displacement was observed during the test, highlighting the occurrence of cyclic hardening phenomena. It was also found that the aligners show a residual strain recovery after removing the applied load. Moreover, in the analyzed range of load rate, the aligners show a low tendency to accumulate residual strains as loading cycles progress

Lagrangian supersymmetries depending on derivatives. Global analysis and cohomology

Lagrangian contact supersymmetries (depending on derivatives of arbitrary order) are treated in very general setting. The cohomology of the variational bicomplex on an arbitrary graded manifold and the iterated cohomology of a generic nilpotent contact supersymmetry are computed. In particular, the first variational formula and conservation laws for Lagrangian systems on graded manifolds using contact supersymmetries are obtained.Comment: 28 pp., appears in 'Communications in Mathematical Physics

Dehydroepiandrosterone (DHEA) supplementation improves in vitro fertilization outcomes of poor ovarian responders, especially in women with low serum concentration of DHEA-S: a retrospective cohort study

Background: Dehydroepiandrosterone (DHEA) is now widely used as an adjuvant for in vitro fertilization (IVF) cycles in poor ovarian responders (PORs). Several studies showed that DHEA supplementation could improve IVF outcomes of PORs. However, most of the PORs do not respond to DHEA clinically. Therefore, the aim of this study is to confirm the beneficial effects of DHEA on IVF outcomes of PORs and to investigate which subgroups of PORs can best benefit from DHEA supplementation. Methods: This retrospective cohort study was performed between January 2015 and December 2017. A total of 151 PORs who fulfilled the Bologna criteria and underwent IVF cycles with the gonadotropin-releasing hormone antagonist protocol were identified. The study group (n = 67) received 90 mg of DHEA daily for an average of 3 months before the IVF cycles. The control group (n = 84) underwent the IVF cycles without DHEA pretreatment. The basic and cycle characteristics and IVF outcomes between the two groups were compared using independent t-tests, Chi-Square tests and binary logistic regression. Results: The study and control groups did not show significant differences in terms of basic characteristics. The study group demonstrated a significantly greater number of retrieved oocytes, metaphase II oocytes, fertilized oocytes, day 3 embryos and top-quality embryos at day 3 and a higher clinical pregnancy rate, ongoing pregnancy rate and live birth rate than those measures in the control group. The multivariate analysis revealed that DHEA supplementation was positively associated with clinical pregnancy rate (OR = 4.93, 95% CI 1.68–14.43, p = 0.004). Additionally, in the study group, the multivariate analysis showed that serum dehydroepiandrosterone-sulfate (DHEA-S) levels < 180 μg/dl were significantly associated with a rate of retrieved oocytes > 3 (OR = 5.92, 95% CI 1.48–23.26, p = 0.012). Conclusions: DHEA supplementation improves IVF outcomes of PORs. In PORs with DHEA pretreatment, women with lower DHEA-S level may have greater possibility of attaining more than 3 oocytes

A phase II study of cetuximab/irinotecan in patients with heavily pretreated metastatic colorectal cancer: Predictive value of early specific toxicities

Background: This study was designed to evaluate the predictive value of early specific toxicities on efficacy of weekly irinotecan/cetuximab administered as salvage therapy in patients with metastatic colorectal cancer (CRC) refractory to oxaliplatin and irinotecan. Patients and Methods: Seventy patients received a regimen composed of weekly irinotecan 125 mg/m(2) as a 1-hour intravenous infusion and cetuximab 400 mg/m(2) infused over 2 hours as the initial dose and 250 mg/m(2) infused over 1 hour for subsequent administrations. A single treatment cycle was composed of 4 weekly irinotecan infusions followed by 2 weeks of rest.The predictive value of adverse events (AEs) attributable to cetuximab (rash) and major toxicities attributable to irinotecan (gastrointestinal [GI] and hematologic) were observed after the first cycle of treatment and, therefore, correlated to activity and efficacy of cetuximab and weekly irinotecan. Results: Sixty-six of 70 patients received >= 1 cycle of chemotherapy and were therefore evaluable for response. Overall, toxicity observed was generally mild and manageable. According to an intent-to-treat analysis, a partial response was exhibited in 15.7% of patients, with a median progression-free survival (PFS) and median overall survival time of 4 months and 9 months, respectively. As expected, PFS (P =.01) and median survival (P =.04) correlated strongly with the presence and severity of the rash. Surprisingly, the presence of at least moderate hematologic and GI toxicity was associated with improved PFS (P =.03). Conclusion: Our data suggest that irinotecan-induced AEs might predict a better outcome in advanced CRC.This finding would identify a different subset of patients-those likely to benefit from a renewed sensitivity to irinotecan induced by cetuximab

Hysteroscopy in the management of endometrial hyperplasia and cancer in reproductive aged women: new developments and current perspectives

Over the last twenty years, the incidence of early endometrial cancer (EC) and atypical endometrial hyperplasia (AEH) among women of reproductive age is increasing rapidly, likely due to a combination of factors including increased prevalence of obesity and delayed of childbirths. Regarding preoperative diagnosis of endometrial neoplasia, it is still debated which is the most accurate and reliable method to obtain endometrial histopathological samples with fractional dilatation and curettage (D&C) having been considered, for a long time, as the method of choice. Nowadays, the advent of in-office endometrial biopsy with or without hysteroscopy has radically changed the approach, giving the opportunity to perform the endometrial biopsy under direct visualization. However, the lack of agreement about its diagnostic accuracy is still relevant. Since a significant number of women with AEH and/or EC are of childbearing age, a fertility-sparing diagnostic and therapeutic approach should be considered in all cases. The feasibility, safety and efficacy of fertility-sparing strategies involving hysteroscopic focal resections in conjunction with hormonal therapies have been evaluated and beneficial effects have been confirmed in several studies and one meta-analysis. Both local and systemic administration of hormonal therapies are currently used. Oral progestin, including medroxyprogesterone acetate (MPA) and megestrol acetate, are the most commonly used therapies. Nowadays, new therapeutic approaches, such as levonorgestrel intrauterine systems (LNG-IUS), gonadotropin-releasing hormone (GnRH) agonists, combined megestrol acetate and metformin, and other combinations of therapies are also used as first line therapies or after the hysteroscopic resection of the lesion. However, it is still unclear which approach provides higher clinical response with lower relapse rate, in addition to preserving fertility in women desiring to conceive. The aim of this narrative review is to summarize the available evidence regarding the evaluation and management with fertility-sparing treatments options of women with AEC and EC

Pregnancy-induced hypertension is an independent risk factor for meconium aspiration syndrome: A retrospective population based cohort study

Objective: Meconium aspiration syndrome (MAS), possibly resulting from fetal hypoxia, is a respiratory distress disorder in the infant. Pregnancy-induced hypertension (PIH) can cause placental dysfunction and lead to fetal hypoxia, which may induce the development of MAS. Therefore, the aim of this study was to determine the association between PIH and MAS and to identify the predictive risk factors. Materials and methods: This was a retrospective cohort study. We selected patients with newly diagnosed PIH and a matched cohort group from the Taiwan National Health Insurance Research Database (NHIRD), from January 1, 2000 till December 31, 2013. For each patient in the PIH cohort, 4 subjects without PIH, matched for age and year of delivery, were randomly selected as the comparison cohort. The incidence of meconium aspiration syndrome was assessed in both groups. Results: Among the 23.3 million individuals registered in the NHIRD, 29,013 patients with PIH and 116,052 matched controls were identified. Patients who experienced PIH had a higher incidence of MAS than did those without PIH. According to a multivariate analysis, PIH (odds ratio [OR] = 1.70, 95% confidence interval [CI] = 1.49–1.93, p < 0.0001) was independently associated with increased risk of MAS. Additionally, age ≥30 years (OR = 1.26, 95% CI = 1.12–1.42, p = 0.0001), nulliparity (OR = 1.13, 95% CI = 1.01–1.27, p = 0.0367) and patients with diabetes mellitus (OR = 3.09, 95% CI = 1.35–7.09, p = 0.0078) were also independent risk factors of MAS. Conclusion: Patients with PIH obtained higher subsequent risk for the development of MAS than those without PIH. Besides, age ≥30 years, nulliparity and patients with diabetes mellitus are the independent risk factors of developing MAS. Keywords: Pregnancy-induced hypertension, Hypertension in pregnancy, Gestational hypertension, Preeclampsia, Meconium aspiration syndrom

Upfront HIPEC and bevacizumab-containing adjuvant chemotherapy in advanced epithelial ovarian cancer

Introduction: In advanced epithelial ovarian cancer patients, the standard of care is primary debulking surgery, followed by first-line chemotherapy often with bevacizumab addiction. In this context, some experiences have shown that a comprehensive treatment approach to surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) could improve the prognosis. Objective: This is a study aimed to explore the feasibility of primary debulking surgery and HIPEC upfront followed by first-line therapy with bevacizumab. Study Design: Phase II monocentric, open label, non-randomised and single-arm study. Forty patients affected by advanced ovarian cancer submitted to primary debulking surgery with HIPEC were enrolled in the study. After surgery, all patients underwent systemic chemotherapy with bevacizumab addiction. Results: Complete cytoreduction (RT = 0) was achieved in all cases. Treatment-related early complications were observed in 23 patients and in 15 cases were G1–G2. Major complications were reported in 8 patients. No postoperative death was recorded. Subsequent chemotherapy was administered in all cases. Median time between surgery and first cycle of chemotherapy was 42 days (range 30–76). Concomitant bevacizumab was administered in 34 patients (85%). Maintenance with bevacizumab was feasible in 33 patients (82.5%) and its withdrawal was necessary for 1 patient (2.5%) due to G3 hypertension. Conclusion: Our data suggest that HIPEC can be safely introduced in the upfront therapy of advanced ovarian cancer