A Case Series of Very Slow Atrioventricular Nodal Reentrant Tachycardia Resembling Junctional Tachycardia

Introduction: The surface EKG of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R’ in V1 and typical heart rates ranging from 150-220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. Methods: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; 1) evidence of dual atrioventricular nodal conduction, 2) tachycardia initiation by atrial drive train with A-H-A response, 3) septal ventriculoatrial (VA) time < 70 ms, and 4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with post pacing interval-tachycardia cycle length (PPI-TCL) > 115ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. Results: We found 11 patients (Age 20-78 years old, 6 female) who met the above-mentioned criteria. The TCL ranged from 560ms to 782ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and PPI-TCL over 115ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. Conclusions: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Atrioventricular Nodal Reentrant Tachycardia Ablation Using Mini-Electrode Recordings

Catheter ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT) is mainly performed using anatomical landmarks. We sought to see whether a new ablation catheter equipped with mini-electrodes may facilitate the mapping of slow pathway potentials for AVNRT ablation. We prospectively included patients referred for AVNRT in our center. Mapping and ablation were performed using an irrigated catheter equipped with 3 insulated mini-electrodes on the distal tip. Thirteen consecutive patients were included (85% female, median age 46 years). Slow pathway potentials could be identified in 77% of cases on mini-electrode bipolar tracings, versus 15% on conventional bipolar tracings (p = 0.0009). At the end of the procedure, double potentials on the ablation line were identified in all patients, only on mini-electrode bipolar tracings. Following ablation, an interval separating double potentials in sinus rhythm ≥15% of baseline tachycardia cycle length was associated with non-inducibility in all patients (p < 0.0001). No recurrence occurred during 1 year of follow-up. The use of mini-electrodes may help target slow pathway potentials during AVNRT ablation. Identification of sufficiently split double potentials on the ablation line might represent an electrophysiological endpoint in these patients.

Crop Cycle Length Determines Optimal Transplanting Date for Seedlings from Hybrid True Potato Seeds

The technology of hybrid breeding in diploid potatoes creates opportunities to design novel and improved cultivation systems based on hybrid true potato seeds. A promising cultivation pathway to produce seed or ware tubers is by transplanting greenhouse-raised seedlings into the field. This study explored the effects of transplanting date and seedling age on tuber yield, using greenhouse-raised seedlings. Field trials with experimental hybrid genotypes were conducted in three consecutive years. In 2017 and 2018, 4- and 6-week-old seedlings were transplanted at four dates: March, April, May and June. In 2019, transplanting dates included April, May and June and seedling age was 5 weeks. In 2018, the March planting experienced severe frost during the initial field period resulting in crop failure. In 2017 and 2019, plants could withstand shorter and less severe frost events. Seedling age did not significantly affect tuber parameters. Transplanting in June resulted in lower marketable yield (> 28 mm) compared with earlier transplanting dates when crops were harvested in September. At full crop senescence, no differences in marketable yield were observed. The optimal transplanting window, taking into account weather-related risks, is approximately between early April and end May. For some genotypes, crop cycle length was observed to be a more important yield-determining factor than transplanting date.

Association between serum 25-hydroxy vitamin D level and menstrual cycle length and regularity: A cross-sectional observational study

Background: Research examining the role of vitamin D deficiency and the development of menstrual disorders in women is of widespread interest. Studies have been published showing that supplementation with high-dose vitamin D can lead to the restoration of the menstrual cycle. We lack adequate information regarding the effect of vitamin D levels on the physiology of menstruation and further on fertility in women of reproductive age due to the contradictory results reported by studies. Objective: To study the association of 25-hydroxy vitamin D with menstrual cycle characteristics including long and short cycle length and cycle irregularity. Materials and Methods: In this cross-sectional study, serum vitamin D levels of 166 women attending an outpatient department with menstrual irregularities after excluding all obvious causes of menstrual disorders (n = 83) between April-June 2019 were measured and were compared with women of similar profiles with complaints other than menstrual irregularities (n = 83). Results: A decreased level of vitamin D was associated with a 13.3 times odds of an irregular cycle (OR (95% CI): 13.30 (5.79-30.60), p < 0.001). 25-hydroxy vitamin D was not associated with age or body mass index. We found a significant difference (p < 0.001) in mean vitamin D levels among the females with irregular cycles vs. regular cycles. Conclusion: Vitamin D plays a role in the physiology of reproduction specific to the menstrual cycle and ovulation. Long-term prospective studies assessing the exact cutoff value and the exact dose of supplementation required are needed. Key words: Menstrual disturbances, Ovulation, Reproductive period, Vitamin D deficiency, Dietary supplements, Polycystic ovarian syndrome.

Minimizing Power Peaking Factor of BEAVRS-based Reactor Using Polar Bear Optimization Algorithms

Fuel loading pattern optimization is a complex problem because there are so many possibilities for combinatorial solutions, and it will take time to try it one by one. Therefore, the Polar Bear Optimization Algorithm was applied to find an optimum PWR loading pattern based on BEAVRS. The desired new fuel loading pattern is the one that has the minimum Power Peaking Factor (PPF) value without compromising the operating time. Operating time is proportional to the multiplication factor (k eff ). These parameters are usually contradictive with each other and will make it hard to find the optimum solution. The reactor was modelled with the Standard Reactor Analysis Code (SRAC) 2006. Fuel pins and fuel assemblies are modelled with the PIJ module for cell calculations. One-fourth symmetry was used with the CITATION X-Y module for core calculations. The optimization was done with 200 populations and 50 iterations. The PPF value for the selected solution should never exceed 2.0 in every burn-up step. Out of 28 solutions, the best optimal fuel loading pattern had a maximum value PPF of 1.458 and a k eff of 0.916 at day 760 of calculated time (corresponding to a cycle length of 479 days). Therefore, the maximum PPF value was 27.1% lower than the safety factor, and the same operating time as the standard loading pattern has been achieved.

Diet and Stress Impair Ovarian Function in Mid-life, Increasing Risk of Chronic Diseases of Aging in Primates

Ovarian dysfunction increases risk for chronic diseases of aging including cardiovascular disease, depression, cognitive impairment, and bone and muscle loss which promote frailty. Psychosocial stress disrupts ovarian function and recent observations suggest that Western diet may also. Determination of causal relationships among diet, psychosocial stress, and ovarian physiology is difficult in humans. Nonhuman primates provide relevant opportunities to investigate diet and psychosocial effects on ovarian physiology and aging because, like humans, they have monthly menstrual cycles and recapitulate many aging-related processes similar to humans. We examined ovarian function in 38 socially housed, middle-aged females fed either a Western or Mediterranean diet for 26 months (~ an 8-year period for humans). During the last 12 months, we examined cycle length, peak progesterone per cycle, and frequency of anovulatory cycles using blood sampling (3/week) and vaginal swabbing (6/week). Repeated measures analysis revealed that like middle-aged women, cycle length increased, and progesterone levels fell over time, suggesting that ovarian dysfunction generally increased in our sample with time. In addition, both Western diet and the stress of low social status reduced progesterone levels, disrupting ovarian function, and increasing risk of chronic diseases of aging. This study demonstrates the additive negative effects of poor diet and psychosocial stress on ovarian physiology in mid-life and lays the groundwork for future investigations to uncover associated metabolic signatures of accelerated aging. The results also suggest that a Mediterranean diet may exert a protective influence against ovarian dysfunction and its pathologic sequelae.