Changes In Cycle Length Research Articles

Atrial Topology for a Unified Understanding of Typical and Atypical Flutter.

Macroreentry stands as the predominant mechanism of typical and atypical flutter. Despite advances in mapping, many aspects of macroreentrant atrial tachycardia remain unsolved. In this translational study, we applied principles of topology to understand the activation patterns, entrainment characteristics, and ablation responses in a large clinical macroreentrant atrial tachycardia database. Because the atrium can be topologically seen as a closed sphere with holes, we used a computational fixed spherical mesh model with a finite number of holes to induce and analyze macroreentrant atrial tachycardia. The ensuing insights were used to interpret high-density activation maps, postpacing interval-tachycardia cycle length values (difference between postpacing interval and tachycardia cycle length), and ablation response in 131 cases of typical and atypical flutter (n=106 left atrium, n=25 right atrium). Modeling of macroreentrant atrial tachycardia revealed that reentry on closed surfaces consistently manifests itself as paired rotation and that an odd number of critical boundaries is mathematically impossible. Together with mathematical confirmation by the index theorem, this led to a unifying construct that could explain the number of loops, difference between postpacing interval and tachycardia cycle length values, and ablation outcomes (termination, no change, or prolongation in tachycardia cycle length) in all 131 cases. Combining topology with the index theorem offers a novel and cohesive framework for understanding and managing typical and atypical flutter.

7299 An Eucaloric High-Fat Diet Suppresses Urinary Estrogen and Progesterone Metabolites, Mimicking Reprometabolic Syndrome in Normal Weight Women

Abstract Disclosure: K. Kuhn: None. A.P. Bradford: Consulting Fee; Self; Amazon. N.F. Santoro: Advisory Board Member; Self; Menogenix, Astellas, Que Oncology, Amazon. Consulting Fee; Self; Ansh. Introduction: Reprometabolic syndrome is associated with relative hypogonadotropic hypogonadism, reduced fecundability, and increased pregnancy loss in women with obesity. We employed a eucaloric, high-fat diet (HFD) to attempt to reproduce the decreased urinary estrogen and progesterone metabolites, characteristic of this phenotype, in healthy women of normal BMI. Materials and Methods: 18 women with normal BMI (18-24.9kg/m²), mean age 29.1±6.3, were recruited for a four-month study including a prescribed 30-day, eucaloric, high-fat, dietary intervention (48% calories from fat). Women collected daily morning urine for 4 menstrual cycles. Daily urinary estrone conjugate (E1c) and pregnanediol-3-glucuronide (Pdg) levels were measured by immunoassay before, during and after the HFD. Paired t tests were used to compare average urinary E1c and Pdg levels and area under the curve (AUC) to determine the impact of the HFD. Cycles were aligned by LH peak (day 0). Results: Participants were weight stable throughout the 4 month study period with no change in BMI (pre-diet BMI 21.46±1.95 kg/m2 and post-diet BMI 21.35±1.81 kg/m2). Average mid cycle E1c peak was significantly lower during (32.4 ng/mg creatinine) and after the HFD (26.5 ng/mg creatinine), compared to pre-diet levels (43.2 ng/mg creatinine; p< 0.001). Post-diet urinary Pdg (AUC) was also significantly lower than pre-diet (p< 0.01). Follicular (days -14 to 0) and luteal phase (days 2-14) E1c AUC was significantly decreased post HFD (p< 0.05). Follicular and luteal phase Pdg levels were also significantly decreased post HFD (p<0.001, both). No significant changes in menstrual cycle length were observed throughout the study. Conclusion: Consumption of a high-fat diet for one month was sufficient to induce a significant reduction in E1c and Pdg, characteristic of Reprometabolic Syndrome of obesity, in normal weight, eumenorrheic women. This finding provides important insights regarding the mechanisms underlying reproductive dysfunction in obesity and indicates that a dietary intervention may be an effective strategy to mitigate sub-optimal reproductive hormone levels in women with obesity-related subfertility. Presentation: 6/1/2024

The prevalence of menstrual changes in COVID-19 vaccinated women: A cross-sectional study

BackgroundThis study aimed to examine the prevalence of menstrual cycle changes (MCs) and their patterns among healthy Syrian women following the administration of the first and second doses of a vaccine. MethodsA cross-sectional online survey following campaigns for COVID-19 vaccines was conducted in 2022 from June 26 to August 3. Data collected included the participants’ demographic characteristics, vaccination status, and multiple-choice questions for MCs changes after the first and second doses. ResultsOf 236, 89.8% completed all shots of the vaccine. After the first dose, 36.9% reported MCs, and 35% after the second dose. Most women did not experience changes in menstrual cycle frequency—81.8% after the first dose and 83.4% after the second dose. Similarly, most women did not observe changes in cycle length, or menstrual flow quantity—5.5% after the first dose and 8% after the second dose reported spotting. Dysmenorrhea was reported by 15.7% and 14.1% of women after the first and second doses, respectively. ConclusionMCs are a potential symptom that a healthy woman at childbearing age could have after a different type of COVID-19 vaccine. MCs patterns do not significantly differ following vaccine doses.

Nucleotide depletion promotes cell fate transitions by inducing DNA replication stress

Control of cellular identity requires coordination of developmental programs with environmental factors such as nutrient availability, suggesting that perturbing metabolism can alter cell state. Here, we find that nucleotide depletion and DNA replication stress drive differentiation in human and murine normal and transformed hematopoietic systems, including patient-derived acute myeloid leukemia (AML) xenografts. These cell state transitions begin during S phase and are independent of ATR/ATM checkpoint signaling, double-stranded DNA break formation, and changes in cell cycle length. In systems where differentiation is blocked by oncogenic transcription factor expression, replication stress activates primed regulatory loci and induces lineage-appropriate maturation genes despite the persistence of progenitor programs. Altering the baseline cell state by manipulating transcription factor expression causes replication stress to induce genes specific for alternative lineages. The ability of replication stress to selectively activate primed maturation programs across different contexts suggests a general mechanism by which changes in metabolism can promote lineage-appropriate cell state transitions.

The association of COVID-19 vaccination and menstrual health: A period-tracking app-based cohort study

BackgroundIn initial COVID-19 clinical trials, menstrual health was not formally monitored, yet anecdotal reports of menstruation changes surfaced on social media. This study aims to assess the association between COVID-19 vaccines and menstruation using Clue, a period-tracking application. Study designA survey assessing demographics, menstrual health, stress levels, and COVID-19 vaccination was sent to Clue users between 12/7/2021 and 2/9/2022. Inclusion criteria were (1) 18 years or older (2) currently menstruating (3) not pregnant or breastfeeding since 1/2020. Menstrual data was collected for each participant. Users with cycle lengths more than 90 days were excluded. Cycle lengths were calculated for the 6-month average pre-vaccination (PRIOR), the cycle during which vaccination was administered (DURING), the cycle following DURING (AFTER1), and the cycle following AFTER1 (AFTER2). For periods, individuals were stratified based on whether vaccination was received during their menstrual period (DURING). Period lengths were additionally calculated for the 6-month average pre-vaccination (PRIOR), the first period following vaccination (AFTER1), and the period following AFTER1 (AFTER2). For unvaccinated participants, an index date (4/1/2022) was used to similarly designate menstrual cycles and periods. For each participant, cycle length changes for DURING, AFTER1, and AFTER2 compared to PRIOR were determined. Student’s t-test compared the mean of these changes between vaccinated and unvaccinated groups. ResultsOf 7,559 participants, 6,897 (91 %) were vaccinated. Compared to PRIOR, individuals vaccinated during their menstrual period demonstrated a statistically significant increase in the DURING period length, but not AFTER1 (p = 0.463) and AFTER2 (p = 0.692). No statistically significant changes were observed in period lengths of those vaccinated in between periods or in cycle lengths overall. ConclusionA small but statistically significant change in period length was observed only in individuals vaccinated for COVID-19 during their menstrual period. Providers can better counsel menstruating individuals to reduce vaccine misinformation.

Clinical assessment of the efficacy of Ayurvedic management in PCOS: Study protocol for a randomized open-label standard control trial

Abstract INTRODUCTION: Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, typically characterized by anovulation, hormonal imbalances, obesity, infertility, and associated features, with a significant impact on the physiological and psychological wellbeing of females belonging to the reproductive age group. Due to the multifactorial etiology, treatment is often personalized with specific targets, and monotherapy is rarely used. In the present study, the efficacy of an Ayurveda regimen, comprising the Ayush-SSM tablet (a coded Ayurvedic formulation) administered after Virechana therapy (purgation), is being explored against conventional standard care. MATERIALS AND METHODS: This study is an open-label, randomized, controlled clinical trial consisting of 180 participants diagnosed with PCOS. The participants in the trial group will receive Ayurvedic treatment consisting of Virechana therapy followed by administration of Ayush-SSM (500 mg), two tablets twice a day for 6 months. The participants in the control group will receive metformin tablet 500 mg once a day in the first week, 500 mg twice a day in the second week, 500 mg thrice a day in the third week, and 850 mg twice a day from the fourth week till 6 months. The primary outcome is the proportion of study participants who attain normal menstrual cycle length (21–35 days) or ovulation and change in hirsutism as per the modified Ferriman–Gallwey (FG) Score. The secondary outcomes are change in acne score and acanthosis nigricans; change in abdominal girth, waist circumference, and BMI; and clinical safety of the trial interventions. CONCLUSION: The findings of the study could potentially demonstrate that the Ayurveda regimen, including Virechana therapy followed by administration of the Ayush-SSM tablet, may be as effective as conventional standard care. Trial registration: Clinical Trial Registry of India (CTRI/2022/09/045478, dated August 4, 2022).

Timing of Coronavirus Disease 2019 (COVID-19) Vaccination and Effects on Menstrual Cycle Changes.

To assess whether menstrual cycle timing (follicular or luteal phase) of coronavirus disease 2019 (COVID-19) vaccine administration is associated with cycle length changes. We used prospectively collected (2021-2022) menstrual cycle tracking data from 19,497 reproductive-aged users of the application "Natural Cycles." We identified whether vaccine was delivered in the follicular or luteal phase and also included an unvaccinated control group. Our primary outcome was the adjusted within-individual change in cycle length (in days) from the average of the three menstrual cycles before the first vaccination cycle (individuals in the unvaccinated control group were assigned a notional vaccine date). We also assessed cycle length changes in the second vaccination cycle and whether a clinically significant change in cycle length (8 days or more) occurred in either cycle. Most individuals were younger than age 35 years (80.1%) and from North America (28.6%), continental Europe (33.5%), or the United Kingdom (31.7%). In the vaccinated group, the majority received an mRNA vaccine (63.8% of the full sample). Individuals vaccinated in the follicular phase experienced an average 1-day longer adjusted cycle length with a first or second dose of COVID-19 vaccine compared with their prevaccination average (first dose: 1.00 day [98.75% CI, 0.88-1.13], second dose: 1.11 days [98.75% CI, 0.93-1.29]); those vaccinated in the luteal phase and those in the unvaccinated control group experienced no change in cycle length (respectively, first dose: -0.09 days [98.75% CI, -0.26 to 0.07], second dose: 0.06 days [98.75% CI, -0.16 to 0.29], unvaccinated notional first dose: 0.08 days [98.75% CI, -0.10 to 0.27], second dose: 0.17 days [98.75% CI, -0.04 to 0.38]). Those vaccinated during the follicular phase were also more likely to experience a clinically significant change in cycle length (8 days or more; first dose: 6.8%) than those vaccinated in the luteal phase or unvaccinated (3.3% and 5.0%, respectively; P <.001). COVID-19 vaccine-related cycle length increases are associated with receipt of vaccination in the first half of the menstrual cycle (follicular phase).

Prolongation of the Menstrual Cycle After Receipt of the Primary Series and Booster Doses of mRNA Coronavirus Disease 2019 (COVID-19) Vaccination.

To quantitatively evaluate the effect of a booster vaccination dose against coronavirus disease 2019 (COVID-19) on menstrual cycle in a large-scale retrospective cohort study using a menstrual cycle tracking smartphone application (app). Prospectively or retrospectively recorded data, including the start and finish dates of menstrual cycles, were collected with the app. Detailed data on vaccinations, side effects, and participants' characteristics were retrospectively collected from a questionnaire on the app. For each COVID-19 vaccination shot (first, second, and third), within-individual changes in menstrual cycle length up to the fourth postvaccination cycle were evaluated. Among the 7,376 and 6,873 participants who had the first and second COVID-19 vaccine doses in different menstrual cycles, respectively, menstrual cycles immediately after the vaccination (first postvaccination cycles) were an average of 0.22 days (95% CI, 0.06-0.39) and 0.37 days (95% CI, 0.20-0.54) longer than the prevaccination cycle. In contrast, among the 1,672 participants who received the first and second doses in the same cycle, the first postvaccination cycle was an average of 4.21 days (95% CI, 3.69-4.72) longer. The second to fourth postvaccination cycles returned to the level of the prevaccination cycle. However, among the 4,768 participants who had the third COVID-19 vaccine dose, the menstrual cycle immediately after the vaccination was an average of 1.20 days (95% CI, 1.00-1.40) longer, with prolongation of cycles of 0.27 days (95% CI, 0.10-0.44) to 0.41 days (95% CI, 0.22-0.59) persisting from the second to the fourth postvaccination cycle. The booster shot against COVID-19 may have a greater and longer-lasting effect on menstrual cycles than the primary-series shots. Although the effect size was small, evidence on the side effects of immunization on menstruation should be accumulated.

The electrical restitution of the non-propagated cardiac ventricular action potential.

Sudden changes in pacing cycle length are frequently associated with repolarization abnormalities initiating cardiac arrhythmias, and physiologists have long been interested in measuring the likelihood of these events before their manifestation. A marker of repolarization stability has been found in the electrical restitution (ER), the response of the ventricular action potential duration to a pre- or post-mature stimulation, graphically represented by the so-called ER curve. According to the restitution hypothesis (ERH), the slope of this curve provides a quantitative discrimination between stable repolarization and proneness to arrhythmias. ER has been studied at the body surface, whole organ, and tissue level, and ERH has soon become a key reference point in theoretical, clinical, and pharmacological studies concerning arrhythmia development, and, despite criticisms, it is still widely adopted. The ionic mechanism of ER and cellular applications of ERH are covered in the present review. The main criticism on ERH concerns its dependence from the way ER is measured. Over the years, in fact, several different experimental protocols have been established to measure ER, which are also described in this article. In reviewing the state-of-the art on cardiac cellular ER, I have introduced a notation specifying protocols and graphical representations, with the aim of unifying a sometime confusing nomenclature, and providing a physiological tool, better defined in its scope and limitations, to meet the growing expectations of clinical and pharmacological research.

Menstrual cycle alterations in reproductive age women after anti COVID-19 vaccination. A survey in 419 Italian women and quality of life and sexual function evaluation.

Pharmacovigilance agencies did not collect data regarding menstrual changes after COVID-19 vaccination even if many women experienced it. Our aim was to evaluate whether COVID-19 vaccination is associated with secondary changes in menstrual cycle and to assess both quality of life (QoL) and sexual function (SF). This study is a retrospective analysis referred to our Department from January 2021 to December 2021. The study cohort responded to same questionnaires before the second dose of vaccination (referring to previous 3 months) and 3 months after that (referring to three menstrual cycles after full-dose vaccination). The surveys administered were FSFI, FSDS, SF-36, MEDI-Q and the VAS-scale for dysmenorrhea. Four-hundred-nineteen vaccinated women were included in the study. The survey did not show a significant change in menstrual cycle length before and after COVID-19 vaccine (5.88±3.67 vs. 4.97±2.89, P=0.21); the interval between periods was significantly higher after a full-cycle vaccination (28.32±7.34 vs. 32.38±7.45, P<0.02); 32 patients (7.6%) developed amenorrhea after the second dose; VAS Scale did not change significantly (median range 3 (3-5) vs. 4 (3-6), P=0.20). MEDI-Q did not show significant variations before and after the vaccination (43.21±11.65 vs. 40.28±9.88, P=0.35). QoL and SF did not change significantly (FSFI median 27 [24-29] vs. 28 [25-30], P=0.12, FSDS median 9 [5-11] vs. 8 [4-12], P=0.22), SF-36 median 81 [70-85] vs. 82 [72-86], P=0.43). COVID-19 vaccination is associated with a significant change in intervals between menstrual cycles without other alterations in menstrual characteristics, in QoL or SF.

Associations Among Menstrual Cycle Length, Coronavirus Disease 2019 (COVID-19), and Vaccination.

To assess whether coronavirus disease 2019 (COVID-19) is associated with menstrual cycle length changes and, if so, how that compares with those undergoing vaccination or no event (control). We conducted a retrospective cohort analysis in which we analyzed prospectively tracked cycle-length data from users of a period tracker application who also responded to a survey regarding COVID-19 symptoms and vaccination. We restricted our sample to users aged 16-45 years, with normal cycle lengths (24-38 days) and regular tracking behavior during the five cycles around COVID-19 symptoms or vaccination or a similar time period for those experiencing no event (control group). We calculated the within-user change in cycle length (days) from the three consecutive cycles preevent average (either vaccination, disease, or neither; cycles 1-3) to the event (cycle 4) and postevent (cycle 5) cycles. We used mixed-effects models to estimate the age- and country-adjusted difference in change in cycle length across the groups. We included 6,514 users from 110 countries representing 32,570 cycles (COVID-19 symptoms: 1,450; COVID-19 vaccination: 4,643; control: 421). The COVID-19 cohort experienced a 1.45-day adjusted increase in cycle length during cycle 4 (COVID-19) compared with their three preevent cycles (95% CI 0.86-2.04). The vaccinated group experienced a 1.14-day adjusted increase in cycle length during cycle 4 (COVID-19 vaccine) compared with their preevent average (95% CI 0.60-1.69). The control group (neither vaccine nor disease) experienced a 0.68-day decrease (95% CI -1.18 to -0.19) in a similar time period. Post hoc tests showed no significant differences in the magnitude of changes between the COVID-19 and vaccination cohorts. In both cohorts, cycle length changes disappeared in the postevent cycle. Experiencing COVID-19 is associated with a small change in cycle length similar to COVID-19 vaccination. These changes resolve quickly within the next cycle.

Effect of COVID-19 vaccinations on menstrual cycle and postmenopausal bleeding among health care workers: A cross-sectional study.

To determine the effect of coronavirus disease 2019 (COVID-19) vaccination and its association with sociodemographic factors on the menstrual cycle in premenopausal women and on postmenopausal bleeding. This is a retrospective cross-sectional study conducted between September 22, 2022, and November 30, 2022, via a questionnaire distributed to 359 health care workers (HCWs) at Lebanese American University Medical Center-Rizk Hospital and St John's Hospital. Inclusion criteria included female Lebanese HCWs who were vaccinated and aged 18 to 65 years. Change in cycle length was significantly associated with age (P = 0.025 after the first dose and P = 0.017 after the second dose), level of education (P = 0.013 after the first dose and P = 0.012 after the second dose), and fibroids (P = 0.006 after the second dose and P = 0.003 after the third dose). The change in cycle flow was significantly associated with age (P = 0.028), fibroids (P = 0.002 after the second dose and P = 0.002 after the third dose), bleeding disorders (P = 0.000), and chronic medications (P = 0.007). The change in symptoms was associated with polycystic ovary syndrome (P = 0.021), chronic medications (P = 0.019 after the second dose and P = 0.045 after the third dose), and fibroids (P = 0.000). COVID-19 vaccination can influence the menstrual cycle. Age, body mass index, level of education, underlying comorbidities, and use of chronic medications are significantly associated with changes in menstrual length, flow, and symptoms following vaccination.

AP-452681-2 6 MONTH FOLLOW-UP OF A SUCCESSFUL FLUOROLESS PEDIATRIC GANGLIONATED PLEXI ABLATION

Cardioneuroablation (CNA) has been shown to treat vagally mediated bradyarrhythmias and vasovagal syncope. In this case, an 8-year-old female with Down’s Syndrome, duodenal atresia, and intermittent nocturnal AV block status post pacemaker without significant cardiopathy underwent successful ganglionated plexi ablation. To discuss the novel use of CNA in pediatric patients for symptomatic vasovagal syncope which can significantly reduce the volume of pacemakers implanted and obviate the need for subsequent lifelong generator replacements and lead revisions. CNA and GP locations were described and reviewed by Garcia et al for cardioinhibitory syncope treatment and prevention.1 Guidelines followed for CNA were well defined by Pachon2 and Aksu3. Localized assessments were performed at areas of complex fractionated signals at main ganglionated plexi (GP) locations. GP/cardiac insertion points are defined through high frequency (HF) EGM analysis with fractionation mapping software (NAVX, Abbott), as 3-5 deflections within the atrial cardiac cycle. Higher frequency signals were localized during mapping and correlated with traditional EGM analysis of 30-500Hz. All catheter positions were visualized with vascular ultrasound and NAVX 3-D mapping. Pacing the vagus nerve 50 Hz/50 microseconds provoked sinus slowing on the left and AV block on the right (figure 2). Fluoroscopy was not utilized. Standard RF targets were set at 60°C with maximum power of 50W. RF lesions were applied to previously defined GP1-4, targeting areas of HF signals4 for a maximum of 60 seconds. HR increase was noted with RF at GP1(18%), and this persisted throughout the case. Wenckebach cycle length change was 13%. Post ablation, HR remained unchanged during stimulation of bilateral vagal nerves. Additionally, there was no change in HR with atropine administration. At 6 month follow up, device check shows 0% pacing. Holter monitor demonstrated transient Wenckebach during sleep. Successful fluoroless GP ablation was performed for recurrent severe cardioinhibitory bradycardia. 6 month follow-up device check 0% pacing burden re-demonstrates sustained success of CNA. Future plans include another 6 months of monitoring followed by pacemaker deactivation and extraction discussion.

COVID-19 Vaccinations and Menstrual Cycle Alteration

The rapid development of safe and effective vaccines against Coronavirus Disease 2019 (COVID-19) has been a triumph of medical sciences, but vaccines only work if people take them. COVID-19 vaccination may be associated with a change in menstrual cycle length following vaccination. Although there is extensive evidence that COVID-19 vaccination does not affect fertility, misinformation is that it could have been a major source of vaccine hesitancy among young women. As the vaccination program was rolled out to younger age groups, some people noticed menstrual changes after the COVID-19 vaccination, and many members of the public found these reports concerning. The research was needed to generate robust data to inform healthcare professionals and the public about these potential side effects. Menstrual changes have been reported in association with a variety of vaccines, including those against pathogens other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), so this work aims to describe SARS-CoV-2 infection and the menstrual cycle changes because of it.

Long COVID-A New Challenge in Medicine: Focus on Pregnancy and Breastfeeding

Long COVID (coronavirus disease) has been described as anew multi-organ disease, which appears to be more prevalent in women than in men. Pregnant and breastfeeding women are aspecial subgroup of patients to consider with long COVID, as only scarce data have been collected to date. Menstrual changes are commonly observed during or after COVID-19; some studies also attribute slight changes of cycle length to previous inoculation against the virus. Pregnant women who have asymptomatic infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) are at ahigher risk for adverse outcomes and pregnancy-associated complications. Moreover, more and robust data are required to evaluate vertical transmission. COVID vaccines are the most effective tool against the pandemic, as they prevent infection, but also appear to be able to ease long COVID symptoms. Vaccines have been proven safe and effective in both pregnant and breastfeeding women. This article aims to present current data on long COVID in pregnant and breastfeeding women and elucidate risk factors and possible treatment options.

Advanced fuel and burnable absorbers designed for long-cycle operation of BNPP

The present study is based on the facts that are happening for the Bushehr Nuclear Power Plant (BNPP) and coincides with the operational changes and step-by-step modifications of the BNPP in the near future. Bushehr reactor core will change from BNPP core to TVS-2M core. In other words, a new fuel, called the TVS-2M, is being used by the Russians to upgrade WWER-1000 reactors to reduce power generation costs, increase cycle length and fuel consumption. The neutronic analysis performed in this work is in line with this change. It provides a feasibility study of BA change and increase of cycle length in BNPP reactor without changing the initial structure of the reactor core. This research provides a new core configuration that can achieve the stated goals to a large extent without changing the BNPP core to the TVS-2M core. This research provides a feasibility study of Integrated burnable absorber (IBA) change by maintaining the initial neutronic conditions and a new high-performance configuration aiming for a long-cycle operation in Iran's nuclear power reactor. In Water-Water Energetic Reactors (WWER) reactors, two alternatives to CrB2Al (current burnable absorber in BNPP) are gadolinia (Gd2O3-UO2), and erbia (Er2O3-UO2). The benefits of the combinational IBA concept are expected by compensating weak points of each other. The main contribution of this research is the use of two cylindrical coaxial IBA layers with the same volume of gadolinium pins plus erbium (separated by a thin layer of zirconium alloy (Zr + 1% Nb)) and gadolinium pins. A neutronic evaluation has been conducted to investigate the variations of effective multiplication factor versus burnup, reactivity swing, power peaking distribution, moderator temperature coefficient (MTC), critical boron concentration (CBC), and cycle length. The result shows that the cycle length can be extended from 296 days in the BNPP core to 366 days in the proposed core, which is comparable to the cycle length of the TVS-2M core. The average BA concentration in the proposed core is 5%, which is lower than the average BA concentration of 5%–8% in the TVS-2M core. Regarding the gain of 73.90 days in cycle length, the revenue is estimated to be around 19,503,000 USD, making it worth the implementation considering the number of gadolinium and erbium pins in the proposed core.

Covid-19 Vaccinations and Menstrual Cycle Alteration

The rapid development of safe and effective vaccines against Coronavirus Disease 2019 (COVID-19) has been a triumph of medical sciences, but vaccines only work if people take them. COVID-19 vaccination may be associated with change in menstrual cycle length following vaccination. Although there is extensive evidence that COVID-19 vaccination does not affect fertility, misinformation that it could has been a major source of vaccine hesitancy among young women. As the vaccination program was rolled out to younger age groups, some people noticed menstrual changes after COVID-19 vaccination, and many members of the public found these reports concerning. Research was needed to generate robust data to inform healthcare professionals and the public about these potential side effects. Menstrual changes have been reported in association with a variety of vaccines, including those against pathogens other than severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), so the aim of this work is to describe SARS-CoV-2 infection and the menstrual cycle changes because of it.

Covid-19 vaccination and menstrual cycle length in the Apple Women’s Health Study

COVID-19 vaccination may be associated with change in menstrual cycle length following vaccination. We estimated covariate-adjusted differences in mean cycle length (MCL), measured in days, between pre-vaccination cycles, vaccination cycles, and post-vaccination cycles within vaccinated participants who met eligibility criteria in the Apple Women’s Health Study, a longitudinal mobile-application-based cohort of people in the U.S. with manually logged menstrual cycles. A total of 9652 participants (8486 vaccinated; 1166 unvaccinated) contributed 128,094 cycles (median = 10 cycles per participant; inter-quartile range: 4–22). Fifty-five percent of vaccinated participants received Pfizer-BioNTech’s mRNA vaccine, 37% received Moderna’s mRNA vaccine, and 8% received the Johnson & Johnson/Janssen (J&J) vaccine. COVID-19 vaccination was associated with a small increase in MCL for cycles in which participants received the first dose (0.50 days, 95% CI: 0.22, 0.78) and cycles in which participants received the second dose (0.39 days, 95% CI: 0.11, 0.67) of mRNA vaccines compared with pre-vaccination cycles. Cycles in which the single dose of J&J was administered were, on average, 1.26 days longer (95% CI: 0.45, 2.07) than pre-vaccination cycles. Post-vaccination cycles returned to average pre-vaccination length. Estimated follicular phase vaccination was associated with increased MCL in cycles in which participants received the first dose (0.97 days, 95% CI: 0.53, 1.42) or the second dose (1.43 days, 95% CI: 1.06, 1.80) of mRNA vaccines or the J&J dose (2.27 days, 95% CI: 1.04, 3.50), compared with pre-vaccination cycles. Menstrual cycle change following COVID-19 vaccination appears small and temporary and should not discourage individuals from becoming vaccinated.

OR15-6 Epidemic of Subclinical Ovulatory Disturbances During SARS-COV2 Pandemic—an Experiment of Nature

Abstract During the SARS-COV2 pandemic (COVID-19) many studies have examined changes in women's stress, depression/anxiety, reproduction, plus post-vaccination cycle/flow changes1. Although there are retrospective basal temperature data2, we lack menstrual cycle and ovulation information during the pandemic. This analysis compared two independent, similar-design, convenience/community-based, single-cycle cohort studies 13 years apart: Menstruation Ovulation Study (MOS3, n=301, 2007-8) and MOS2 (n=112) during the pandemic. With MOS as a control, and given evidence subclinicalovulatory disturbances (SOD; short luteal phase/anovulatory menstrual cycles of normal lengths) occur before changed cycle lengths4 5, we hypothesized MOS2 would have increased SOD but similar cycle lengths as MOS. Methods In both studies, recruitment of menstruating women ages 19-35 years, not using systemic or combined hormonal contraceptives (CHC) used posters/eblasts/social media. In MOS, ovulation was assessed by 3-fold increased follicular (FP)-to-luteal (LP/premenstrual) urinary progesterone (PdG); in MOS2, by validated Quantitative Basal Temperature© (QBT)6 7 (normal LP=10+ days). We performed the same interviewer-administered (CaMos©) questionnaire for demographics, SES, and reproduction, measured anthropomorphic variables, plus collected daily Menstrual Cycle Diary© (Diary) for all. FP and LP/premenstrual PdG or salivary progesterone (Ps) samples were respectively collected. Participants in MOS2 were not different from MOS in: average age 29, menarche age 12.5, BMI 24, living situation and education (≥75% university graduates). Cohorts also differed: MOS2 women were less likely to to be White (56% vs 76%), work fulltime, ever use CHC (68% vs 79%) or to be parous (8% vs 20%); they were younger at starting CHC (17.9 vs 18.6 years). Results MOS2 and MOS had similar cycle (30.3 vs 29.9 days, P =.306) and flow lengths (median 6.0 days; P=.055). MOS2 recorded significantly more SOD cycles (&amp;gt;50% anovulatory) vs MOS3 (63% vs 10%; P&amp;lt;.001). MOS2 Diary analyses by Principal Components Analysis showed significantly increased anxiety/depression/frustration (negative moods) and "outside stresses" plus sleep problems and headaches vs MOS (all P&amp;lt;.001). Discussion This is the first evidence that ovulatory disturbances without cycle length changes may be associated with the multidimensional stresses women experience during the pandemic. Increased SOD may also relate to greater nulliparity, younger CHC teen use and more non-White women in MOS2, as well higher prevalence of negative moods, outside stresses and sleep problems. Salivary progesterone, cortisol and estradiol levels remain pending. Prevalent SOD cycles, if persistent/recurrent, risk increased infertility, bone loss5, early heart attacks, and breast and endometrial cancers8. In this 'experiment of nature,' the pandemic was associated with disturbed ovulation rather than menstrual cycles. 1Edelman AB Ob Gyn 2022; 2Nguyen JK PLOS ONE 2021; 3Prior JC IJERPH 2018; 4Prior JC NEJM 1990; 5Li D Epidiol Rev 2014; 6Prior JC Clin Invest. Med 1990; 7Bedford JL Eur J ObGyn Reprod Biol 2009; 8Prior JC DDDM 2020. Presentation: Sunday, June 12, 2022 12:15 p.m. - 12:30 p.m.

Sensitivity Analysis of Cardiac Alternans and Tachyarrhythmia to Ion Channel Conductance Using Population Modeling.

Action potential duration (APD) alternans, an alternating phenomenon between action potentials in cardiomyocytes, causes heart arrhythmia when the heart rate is high. However, some of the APD alternans observed in clinical trials occurs under slow heart rate conditions of 100 to 120 bpm, increasing the likelihood of heart arrhythmias such as atrial fibrillation. Advanced studies have identified the occurrence of this type of APD alternans in terms of electrophysiological ion channel currents in cells. However, they only identified physiological phenomena, such as action potential due to random changes in a particular ion channel's conductivity through ion models specializing in specific ion channel currents. In this study, we performed parameter sensitivity analysis via population modeling using a validated human ventricular physiology model to check the sensitivity of APD alternans to ion channel conductances. Through population modeling, we expressed the changes in alternans onset cycle length (AOCL) and mean APD in AOCL (AO meanAPD) according to the variations in ion channel conductance. Finally, we identified the ion channel that maximally affected the occurrence of APD alternans. AOCL and AO meanAPD were sensitive to changes in the plateau Ca2+ current. Accordingly, it was expected that APD alternans would be vulnerable to changes in intracellular calcium concentration.