Complexities And Potential Pitfalls Of Clinical Study Design And Data Analysis In Assisted Reproduction

Purpose of review: The purpose of the current review is to describe the common pitfalls in design and statistical analysis of reproductive medicine studies. It serves to guide both authors and reviewers toward reducing the incidence of spurious statistical results and erroneous conclusions. Recent findings: The large amount of data gathered in IVF cycles leads to problems with multiplicity, multicollinearity, and over fitting of regression models. Furthermore, the use of the word \u27trend\u27 to describe nonsignificant results has increased in recent years. Finally, methods to accurately account for female age in infertility research models are becoming more common and necessary. Summary: The pitfalls of study design and analysis reviewed provide a framework for authors and reviewers to approach clinical research in the field of reproductive medicine. By providing a more rigorous approach to study design and analysis, the literature in reproductive medicine will have more reliable conclusions that can stand the test of time

Exploration of Charge Recycling DC-DC Conversion Using a Switched Capacitor Regulator

The increasing popularity of DVFS (dynamic voltage frequency scaling) schemes for portable low power applications demands highly efficient on-chip DC-DC converters. The primary aim of this work is to enable increased efficiency of on-chip DC-DC conversion for near-threshold operation of multicore chips. The idea is to supply nominal (high) off-chip voltage to the cores which are then “voltage-stacked” to generate the near-threshold (low) voltages based on Kirchhoff’s voltage law through charge recycling. However, the effectiveness of this implicit down-conversion is affected by the current imbalance among the cores. The paper presents a design methodology and optimization strategy for highly efficient charge recycling on-chip regulation using a push-pull switched capacitor (SC) circuit. A dual-boundary hysteretic feedback control circuit has been designed for stacked loads. A stacked-voltage domain with its self-regulation capability combined with a SC converter has shown average efficiency of 78%–93% for 2:1 down-conversion with ILoad (max) of 200 mA and workload imbalance varying from 0–100%

Virtual reality-based training for the diagnosis of prostate cancer

Prostate malignancies are the second leading cause of cancer deaths among men. The most common method of detecting this disease is digital rectal examination (DRE). Current DRE training is inadequate, since the number of patients that students can practice on is limited. Furthermore, allied care personnel do not train in screening for prostate cancer. Finally, there is no objective way to follow the improvement in DRE skills for medical personnel. This paper presents a virtual reality-based simulator that addresses the above problems. The prototype consists of a PHANToM haptic interface which provides feedback to the trainee's index finger, a motion restricting board, and an SGI workstation, which renders the patient's anatomy. Four types of prostates were modeled--normal, enlarged with no tumor, incipient malignancy (single tumor), and advanced malignancy (tumor cluster). Human factors studies were conducted on both nonmedical students and urology residents in order to quantify the system usefulness. After only five minutes of training, nonmedical students had a 67% correct diagnosis rate of malignant versus nonmalignant cases. This compared with 56% for urology residents in the same trials. Subjective evaluation by the residents pointed out the need to improve the virtual prostate model realism. A control group formed of urology residents performed the same trials on a modified Merck Procar simulator. The control group scored significantly better (96% correct diagnosis of malignancies). We conclude that the virtual prostate palpation simulator, while promising, needs significant improvement in both model realism and haptic interface hardware

Virtual Reality Training for the Diagnosis of Prostate Cancer

Prostate cancer is the second leading cause of cancer death among men (25% of men with prostate cancer will die of the disease). The most common method of detecting this malignancy is digital rectal examination (DRE). Current DRE training requires medical students to examine a large number of patients before attaining adequate experience. We propose to solve this problem using a virtual reality digital rectal examination simulation. The prototype system consists of a PHANToM haptic interface which provides feedback to the trainee's index finger, a motion restricting board and an SGI workstation, which renders the patient 's anatomy in the region of interest. Four types of prostate were modeled using OpenGL and GHOST haptic library-- normal, enlarged with no tumor, incipient malignancy (single tumor), and advanced malignancy (tumor cluster). Results of initial human factors studies are encouraging, while pointing out the need for more realistic physical modeling. 1 Introduction Prosta..

Three-dimensional ultrasound diagnosis of adenomyosis is not associated with adverse pregnancy outcome following single thawed euploid blastocyst transfer: prospective cohort study.

OBJECTIVES: The objectives of this study were (1) to assess the prevalence of ultrasound (US) features of adenomyosis in an infertile population undergoing in-vitro fertilization (IVF), (2) to define the inter- and intrarater agreement of three-dimensional (3D) US assessment of adenomyosis, and (3) to evaluate sonographic features of adenomyosis with respect to pregnancy outcome following transfer of a single thawed euploid blastocyst. METHODS: This was a prospective cohort study. Subjects scheduled to undergo a single thawed euploid blastocyst transfer between April and December 2017 at a large IVF center were eligible for inclusion. Enrolled subjects underwent endometrial preparation for frozen embryo transfer. 3D-US was performed on the day prior to embryo transfer, with images stored for subsequent evaluation. Subjects then underwent transfer of a single thawed euploid blastocyst, and pregnancy outcomes were collected. All 3D-US volumes were de-identified and reviewed independently by five reproductive endocrinologists/infertility specialists with expertise in gynecological US for the presence of seven sonographic features of adenomyosis: global uterine enlargement, myometrial wall asymmetry, heterogeneous echogenicity, irregular junctional zone, myometrial cysts, fan-shaped shadowing and ill-defined myometrial lesions. Adenomyosis was considered to be present if the majority of the reviewers noted at least one of the seven sonographic features. Inter- and intrarater agreement was evaluated using Fleiss\u27s kappa. Clinical and cycle characteristics of subjects with and those without adenomyosis were compared. The primary outcome of interest was live birth rate. Secondary outcomes included clinical pregnancy rate and miscarriage rate. Logistic regression analysis was performed to account for potential confounders. RESULTS: A total of 648 subjects were included. The prevalence of adenomyosis on US was 15.3% (99/648). On retrospective chart review, very few patients with adenomyosis had symptoms. The inter- and intrarater agreement amongst five independent specialists conducting the 3D-US assessments of adenomyosis were poor (κ = 0.23) and moderate (κ = 0.58), respectively. Subjects with adenomyosis were older (37.1 vs 35.9 years, P = 0.02) and more likely to undergo a gonadotropin-releasing hormone agonist downregulation protocol when compared with those without adenomyosis (12.1% vs 5.1%, P = 0.02). Clinical pregnancy (80.0% vs 75.0%) and live birth (69.5% vs 66.5%) rates were similar between the groups. When adjusting for potential confounders, there was no difference in the rate of clinical pregnancy (adjusted odds ratio (aOR), 1.47 (95% CI, 0.85-2.56)), miscarriage (aOR, 1.3 (95% CI, 0.62-2.72)) or live birth (aOR, 1.28 (95% CI, 0.78-2.08)) between subjects with and those without adenomyosis. No individual sonographic marker of adenomyosis was predictive of pregnancy outcome. CONCLUSIONS: The inter-rater agreement of 3D-US assessment of adenomyosis is poor. Furthermore, sonographic markers of adenomyosis in asymptomatic patients may not be associated with altered pregnancy outcome following transfer of a single thawed euploid blastocyst. These findings suggest that routine screening for asymptomatic adenomyosis in an unselected infertile patient population undergoing frozen embryo transfer may not be warranted. © 2020 International Society of Ultrasound in Obstetrics and Gynecology