Natural Cycle Research Articles

Anthropic-Induced Variability of Greenhouse Gasses and Aerosols at the WMO/GAW Coastal Site of Lamezia Terme (Calabria, Southern Italy): Towards a New Method to Assess the Weekly Distribution of Gathered Data

The key to a sustainable future is the reduction in humankind’s impact on natural systems via the development of new technologies and the improvement in source apportionment. Although days, years and seasons are arbitrarily set, their mechanisms are based on natural cycles driven by Earth’s orbital periods. This is not the case for weeks, which are a pure anthropic category and are known from the literature to influence emission cycles and atmospheric chemistry. For the first time since it started data gathering operations, CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane) and eBC (equivalent black carbon) values detected by the Lamezia Terme WMO/GAW station in Calabria, Southern Italy, have been evaluated via a two-pronged approach accounting for weekly variations in absolute concentrations, as well as the number of hourly averages exceeding select thresholds. The analyses were performed on seven continuous years of measurements from 2016 to 2022. The results demonstrate that the analyzed GHGs (greenhouse gasses) and aerosols respond differently to weekly cycles throughout the seasons, and these findings provide completely new insights into source apportionment characterization. Moreover, the results have been combined into a new parameter: the hereby defined WDWO (Weighed Distribution of Weekly Outbreaks) normalizes weekly trends in CO, CO2, CH4 and eBC on an absolute scale, with the scope of providing regulators and researchers alike with a new tool meant to better evaluate anthropogenic pollution and mitigate its effects on the environment and human health.

Connecting Education and Nature: The Benefits of Direct Contact with the Natural Environment for the Holistic Development of Ninth-Grade Students at the Municipal School Prof. Dr. Amaro Fernandes de Oliveira Sobrinho

This study examined the benefits of direct contact with nature for ninth-grade students at Escola Municipal Prof. Dr. Amaro Fernandes de Oliveira Sobrinho. It emphasized hands-on experiences, such as visits to farms, the establishment of vegetable gardens, and the revitalization of existing gardens. These activities were designed to enhance academic learning and promote the holistic development of students. Interaction with the environment provided a deeper understanding of ecosystems and sustainable practices, enabling students to directly engage with concepts such as natural cycles and environmental impacts. In addition to the academic advantages, outdoor experiences have been shown to improve students' emotional well-being by reducing stress and fostering a sense of overall wellness. The activities also cultivated social skills, including communication and collaboration, by involving students in group projects. Immersion in nature contributed to a more collaborative and inclusive atmosphere, while sustainability practices heightened environmental awareness. The findings underscore the importance of integrating natural experiences into the school curriculum to facilitate more meaningful learning and prepare students to become responsible and well-rounded citizens in an increasingly urban and digital world.

Mechanical Properties of Permeable Concrete Reinforced with Polypropylene Fibers for Different Water–Cement Ratios

Permeable concrete is a material that allows water filtration, reduces surface runoff, and maintains the natural water cycle. Previous studies have shown that its mechanical properties, particularly its compressive and flexural tensile strengths, are generally lower than those of conventional concrete, with significant variability observed among similar tests. This study investigates the compressive strength, flexural strength, and permeability of polypropylene fiber-reinforced permeable concrete specimens at two water–cement ratios (0.30 and 0.35). The mix design was conducted using the ACI 522R-10 method. Forty-eight cylinders measuring 200 mm × 100 mm were fabricated for permeability and compression tests. Additionally, 12 beams measuring 100 mm × 100 mm × 350 mm were produced and subjected to simple flexural testing in accordance with ASTM C78 guidelines. Compressive strength versus permeability and load versus deflection graphs were plotted, and the fracture energy was calculated for various deflections. The results indicate that the addition of fibers increased permeability and tensile strength but decreased compressive strength. Furthermore, an increase in the water–cement ratio led to higher compressive and flexural tensile strengths.

Characterization of Silica Sand-Based Pervious Bricks and Their Performance under Stormwater Treatment

The acceleration of urbanization has disrupted natural water cycles, resulting in increased impervious urban surfaces and non-point source pollution from stormwater runoff. Addressing urban stormwater recharge has become crucial. This study introduces a novel silica sand-based permeable filtration material, investigating its surface characteristics, pore structure, permeability, and pollutant interception capabilities. The results demonstrate that hydrophilic binder coating modification of the permeable surface sand aggregate, combined with hydrophilic inorganic additives, having a porous structure with an average pore size of less than 50 μm and a porosity between 15% and 35%, significantly enhances surface hydrophilicity, achieving a permeation rate of up to 6.8 mL/(min·cm²). Moreover, it shows exceptional filtration and anti-clogging properties, achieving over 98% suspended solids interception and strong resistance to fouling. Dynamic biofilm formation experiments using simulated rain and domestic wastewater explore biofilm morphology and function on silica sand filtration well surfaces. Mature biofilms sustain COD removal efficiency exceeding 70%, with levels consistently below 50 mg/L, NH4+ decreasing to 2 mg N/L, and total nitrogen maintained below 10 mg N/L. The system features anoxic, anoxic, and aerobic zones, fostering synergistic organic matter and nitrogen removal by diverse microorganisms, enhancing pollutant mitigation. Silica sand-based permeable filtration material effectively mitigates urban stormwater runoff pollutants—suspended solids, organic matter, and nitrogen—offering an innovative solution for sponge city development and rainwater resource management.

Optimizing trigeneration energy systems: Biogas-centric methanol production via direct CO2 hydrogenation with advanced integration of PEM electrolyzer and LNG cold technology

Biogas, a sustainable alternative to fossil fuels, addresses issues of non-renewability and accessibility. Its structural similarity to fossil fuels makes it a potent option for energy systems. With this in mind, this paper discusses a novel trigeneration system that utilizes biogas and Liquefied natural gas cooling to produce methanol, electricity, cold water, hot water, oxygen, and natural gas. The system integrates various components such as a biogas burner, Kalina cycle, organic Rankine cycle, liquefied natural gas liquid gasification cycle, proton exchange membrane electrolyzer, and methanol synthesis unit. Simulation via Aspen HYSYS software includes an analysis of energy, exergy, economic, and environmental aspects. Efficiency assessment in single generation, cogeneration, trigeneration, and chemical trigeneration modes concludes chemical trigeneration as most efficient, with the proton exchange membrane electrolyzer being the most efficient subsystem. Key variables like Kalina cycle evaporator temperature, gas flow rate to the methanol reactor, and organic Rankine cycle working fluid pressure are assessed. Predictions on thermodynamic, environmental, and economic behaviors, along with their fluctuations, are made. Using a thermoeconomic approach, the economic analysis determines an exergy unit cost of 59.79 $/GJ and a total cost rate of 2764 $/h. Overall, this work presents a novel and efficient chemical trigeneration system that utilizes biogas and LNG cooling to produce multiple products.

Mercury isotope fractionation and mercury source analysis in coal

Understanding the sources of mercury (Hg) in coal is crucial for understanding the natural Hg cycle in the Earth's system, as coal is a natural Hg reservoir. We conducted analyses on the mass-dependent fractionation (MDF), reported as δ202Hg, and mass-independent fractionation (MIF), reported as Δ199Hg, of Hg isotopes among individual Hg species and total Hg (THg) in Chinese coal samples. This data, supplemented by a review of prior research, allowed us to discern the varying trend of THg isotope fractionation with coal THg content. The Hg isotopic composition among identified Hg species in coal manifests notable disparities, with species exhibiting higher thermal stability tending to have heavier δ202Hg values, whereas HgS species typically display the most negative Δ199Hg values. The sources of Hg in coal are predominantly attributed to Hg accumulation from the original plant material and subsequent input from hydrothermal activity. Hg infiltrates peat swamps via vegetation debris, thus acquiring a negative Δ199Hg isotopic signature. Large-scale lithospheric Hg recycling via plate tectonics facilitates the transfer of Hg with a positive Δ199Hg from marine reservoirs to the deep crust. The later-stage hydrothermal input of Hg with a positive Δ199Hg enhances coal Hg content. This process has resulted in an upward trend of Δ199Hg values corresponding with the increase in coal THg content, ultimately leading to near-zero Δ199Hg in high-Hg coals. Coal Hg reservoirs are affected by large-scale natural Hg cycling, which involves the exchange of Hg between continents and seas.

Eco-Friendly synergistic energy generation: Co-Ni2S4 nanoparticles with S-g-C3N4 as a dual-action electrocatalyst for sustainable water splitting

The most appealing technique for producing hydrogen fuel is electrochemical water splitting, which uses natural water cycle capabilities from renewable sources. The transition metal sulfide family includes nickel sulfide (NiS), which is promising for electrochemical water splitting as an exceptionally efficient, stable, and active electrocatalyst. Nickel sulfide (NiS), a series of cobalt-doped nickel sulfide (CoNi2S4) by varying weight percentages of Co (2, 4, 6, 8, wt %) and a series of sulfur-doped graphitic carbon nitride (SGCN) composite with 6 % CoNi2S4 by varying weight percentage of SGCN (10, 30, 50, 70, 90, wt %) were all synthesized using one-pot hydrothermal method. Structural morphologies and composition of the synthesized nanoparticles (NPs) and nanocomposites (NCs) were investigated using SEM, EDX, FTIR, and XRD characterization techniques. The electrochemical performance was examined via voltammetric, electrochemical impedance, and chronoamperometric studies. Outcomes suggest that composite 70 % SGCN@6 % CNS is the best electrocatalyst with the smaller Tafel slope (107 mVdec-1), lowest overpotentials (440 mV@10 mAcm−2), and minor charge transfer resistance (15 Ω) as electrode materials for electrochemical water splitting. The present research provides a workable approach for creating efficient bifunctional electrocatalysts for total water splitting, it can be inferred from the data.

Dog ectoparasites as sentinels for pathogenic Rickettsia and Bartonella in rural Guatemala

Fleas and ticks serve as vectors of multiple pathogens in the genera Rickettsia and Bartonella that cause diseases in humans and other animals. Although human rickettsiosis and bartonellosis have been reported in all countries in Central America, limited research has been conducted to investigate the natural cycles of flea- and tick-borne rickettsiosis and bartonellosis, especially in Guatemala. We evaluated dog parasites as sentinels for zoonotic disease risk in rural Guatemala by sampling ticks and fleas from dogs, which were then identified and individually screened for Rickettsia and Bartonella. A total of 77 households were surveyed and 80.5 % of them had dogs. Overall, 133 dogs were examined for fleas and ticks, of which 68.4 % had fleas and 35.3 % had ticks. A total of 433 fleas and 181 ticks were collected from the infested dogs, with an additional 33 ticks collected from house walls. Three flea species were identified: Ctenocephalides felis (70.0 %), Echidnophaga gallinacea (11.8 %), and Pulex sp. (17.8 %). Among the collected ticks, 97 % were identified as Rhipicephalus sanguineus sensu lato with the rest being Amblyomma cajennense, A. auricularium, and A. ovale. Rickettsia felis were detected in six C. felis, in one Pulex sp., and in two R. sanguineus sensu lato, while Candidatus R. senegalensis was detected in one C. felis. Bartonella was detected only in fleas, including three Pulex sp. infected with B. vinsonii subsp. berkhoffii, B. henselae, and Bartonella sp., respectively, and 11 C. felis infected with B. henselae. This study reports Candidatus R. senegalensis and B. vinsonii subsp. berkhoffii in Guatemala for the first time, and indicates the potential risk of human and dog exposure to Rickettsia and Bartonella species. These results show that dogs provide critical information relevant to managing human potential exposure to flea- and tick-borne pathogens in rural Guatemala. This approach can potentially be expanded to other regions in Central America where domestic dogs are abundant and suffer from ectoparasite infestation.

Outcomes of IVF treatments in women with antiphospholipid antibodies or antiphospholipid syndrome

BackgroundOvulation induction for in vitro fertilization (IVF) may increase intravascular thromboses among patients with antiphospholipid autoantibodies (aPLs) or antiphospholipid syndrome (APS) due to the high estrogen levels. While natural or modified natural IVF treatment cycles (MNC) are sometimes used instead of stimulated cycles with empiric anticoagulant treatment among these infertile patients, their efficacy is unclear. Materials and methodsA retrospective cohort study including all IVF cycles of patients diagnosed with aPLs or APS in a tertiary, university-affiliated hospital between 2012 and 2022. The outcomes of stimulated cycles with anticoagulants and MNC and natural IVF cycle attempts were compared. Results121 oocyte retrievals from 38 women were analyzed: 93 stimulated and 28 MNC or natural IVF cycles. The rates of cycle cancellation (0 % vs. 17.9 %, p < 0.001) and cycles in which no oocytes were retrieved (0 % vs. 43.5 %, p < 0.001) were significantly lower following stimulated cycles vs. natural and MNC. In parallel, positive β-hCG (31.9 % vs. 10.9 %, p = 0.03), clinical pregnancy rate (23.6 % and 3.6 %, p < 0.001) and live birth rates (18.1 % vs. 3.6 %, p = 0.01) were significantly higher following stimulated cycles. No thrombotic events or bleeding occurred in any cycle. ConclusionOvarian stimulation for IVF is more effective for successful pregnancy and delivery than natural cycles and MNC and can be safely undertaken in aPLs or APS women undergoing IVF. Rates of complication from hormonal treatment are not increased when treated with LMWH during ovarian stimulation.

CD26 Is Differentially Expressed throughout the Life Cycle of Infantile Hemangiomas and Characterizes the Proliferative Phase.

Infantile hemangiomas (IHs) are benign vascular neoplasms of childhood (prevalence 5-10%) due to the abnormal proliferation of endothelial cells. IHs are characterized by a peculiar natural life cycle enclosing three phases: proliferative (≤12 months), involuting (≥13 months), and involuted (up to 4-7 years). The mechanisms underlying this neoplastic disease still remain uncovered. Twenty-seven IH tissue specimens (15 proliferative and 12 involuting) were subjected to hematoxylin and eosin staining and a panel of diagnostic markers by immunohistochemistry. WT1, nestin, CD133, and CD26 were also analyzed. Moreover, CD31pos/CD26pos proliferative hemangioma-derived endothelial cells (Hem-ECs) were freshly isolated, exposed to vildagliptin (a DPP-IV/CD26 inhibitor), and tested for cell survival and proliferation by MTT assay, FACS analysis, and Western blot assay. All IHs displayed positive CD31, GLUT1, WT1, and nestin immunostaining but were negative for D2-40. Increased endothelial cell proliferation in IH samples was documented by ki67 labeling. All endothelia of proliferative IHs were positive for CD26 (100%), while only 10 expressed CD133 (66.6%). Surprisingly, seven involuting IH samples (58.3%) exhibited coexisting proliferative and involuting aspects in the same hemangiomatous lesion. Importantly, proliferative areas were characterized by CD26 immunolabeling, at variance from involuting sites that were always CD26 negative. Finally, in vitro DPP-IV pharmacological inhibition by vildagliptin significantly reduced Hem-ECs proliferation through the modulation of ki67 and induced cell cycle arrest associated with the upregulation of p21 protein expression. Taken together, our findings suggest that CD26 might represent a reliable biomarker to detect proliferative sites and unveil non-regressive IHs after a 12-month life cycle.

Effects of acute estradiol administration on perimenstrual worsening of working memory, verbal fluency, and inhibition in patients with suicidal ideation: A randomized, crossover clinical trial

Accumulating evidence indicates that most female patients with suicidal ideation (SI) experience a dimensional worsening of depressive symptoms and SI in the perimenstrual phase of the menstrual cycle. Experimental trials demonstrate that acute perimenstrual administration of estradiol (E2; with or without progesterone/P4), can prevent these recurring episodes of increased risk. In this archival sample drawn from one of these clinical trials, we examined whether these beneficial E2 effects extend to specific types of cognition. For a double-blind, placebo-controlled experiment, we recruited transdiagnostic psychiatric outpatients with natural menstrual cycles who experienced past-month SI (N(per-protocol sample)=23; N(intent-to-treat sample)=44). In each of two counterbalanced conditions (perimenstrual administration of 0.1mg/d transdermal E2 vs. placebo), participants completed three cognitive tasks in three menstrual cycle phases (mid-luteal, perimenstrual, mid-follicular). Multilevel models revealed a significant interaction of condition and phase: E2 administration prevented mid-luteal-to-perimenstrual drops in working memory (p=.006) and verbal fluency (p=.005) observed under placebo. No effects were found for inhibitory control. In conclusion, we find perimenstrual declines in working memory and verbal fluency in patients with SI, which can be prevented by administering E2. This study contributes to our understanding of the hormone-brain pathways involved in the cyclical worsening of suicidality.

Assessment of the Restoration Potential of Forest Vegetation Coverage in the Alxa Desert Region of China.

To scientifically evaluate the sustainability of tree planting and afforestation in the Alxa Desert region, this study, grounded in the principles of water balance within the natural water cycle, employed multi-source remote sensing products and ground-based measurements to construct a quantitative response relationship model. This model links evapotranspiration (ET) with meteorological variables and the Enhanced Vegetation Index (EVI). Furthermore, the study estimated the recovery thresholds and potential of forest and grassland vegetation coverage in the Alxa Desert region under various precipitation scenarios. The findings reveal that ET exhibited an increasing trend in 84.17% of the Alxa Desert region, with a significant increase observed in 61.53% of the area, indicating positive outcomes from the implementation of the Three-North Shelterbelt Forest Program. Notably, however, ET in the southeastern plain region demonstrated a decreasing trend, which is strongly associated with human activities. The response relationship model demonstrated that linear relationship areas constituted 47.52%, while nonlinear relationship areas accounted for 45.51% of the total. The overall model exhibited an R2 value of 0.69, indicating a high level of predictive accuracy. Analysis of forest and grassland coverage revealed that, under wet year scenarios, the vegetation coverage showed a significant trend of recovery, with an average recovery threshold of (75.4 ± 12.5)% and an average recovery potential of (8.5 ± 3.6)%. It is noteworthy that the vegetation coverage in 31.25% of the area had already surpassed the recovery threshold. The outcomes of this study provide a theoretical foundation for the formulation of more scientifically rigorous ecological restoration strategies in the future.

Altered Expression of C4BPA and CXCL1 Genes in the Endometrium of Patients with Recurrent Implantation Failure after In Vitro Fertilization and Thin Endometrium.

Currently, recurrent implantation failure (RIF) after in vitro fertilization is a problem that is commonly faced by reproductive specialists. The phenomenon of a thin endometrium in RIF patients is not yet completely understood or sufficiently treated. This study aimed to reveal the dysregulated expression of selected genes between RIF patients with a thin endometrium and fertile women. Endometrial samples were collected in the implantation window (21-24 days of the natural menstrual cycle) from RIF patients (n = 20) and fertile women (n = 14). Ten genes were chosen as target genes regarding their possible relations with the implantation process. The endometrial gene expression levels showed differences in RIF samples compared to fertile samples. Significant downregulation was observed for the CXCL1 (p = 0.005) and C4BPA (p = 0.03) genes. There was no statistically significant difference between the RIF group and the fertile group in the expression of eight genes: CXCL8, HPRT1, MMP10, INFG, VEGFB, HAND2, IL-15, and TNC (p > 0.05). The use of a combination of two markers (C4BPA + CXCL1) allows for the good discrimination of RIF patients from fertile women (AUC 0.806).

Biomimetic Entropy-Dominant Molecular Hinges with Picomolar Affinity.

Molecular hinges are ubiquitous in both natural and artificial supramolecular systems. A major challenge to date, however, has been simultaneously achieving high thermodynamic and kinetic stability. Here, we employ host-enhanced intramolecular charge-transfer interactions to mediate entropy-favored complexation between a flexible AB2-type guest and a macrocyclic host, forming a new type of molecular hinge with an ultrahigh picomolar binding affinity (Ka > 1012 M-1). This entropy-promoted hinge modulates photoisomerization, exhibiting a substantial preference for the E-isomer, which is further demonstrated to mirror the natural retinal-opsin cycle, promoting the sensitization of visible light. This work unveils an efficient approach to exploit entropy-dominant architectures for the design of hierarchical molecular systems.

Assessing Carbon Capture and Carbonation in Recycled Concrete Aggregates: A Holistic Life Cycle Assessment Perspective with Simulation at Industrial Scale

This work explores a life cycle assessment (LCA) concerning carbon capture and carbonation of recycled concrete aggregates (RCA), addressing the growing challenges posed by increased carbon emissions in power generation and ecological concerns tied to construction waste. We propose an integrated solution involving the capture of low-concentration carbon dioxide (CO2) from natural gas combined cycle (NGCC) power plants through aqueous ammonia absorption and sequestration by mineralization of RCA. The cradle-to-gate LCA focuses on an industrial-scale scenario for capturing 200 kilotonnes of CO2 annually, with functional unit per tonne of carbonated RCA output. The findings reveal a net positive carbon abatement of 21.42 kg CO2 eq., with heat production and electricity consumption being the major contributors to global warming potential (GWP). Within the spectrum of environmental impact categories under study, Marine Aquatic Ecotoxicity Potential (MAETP) exhibits a significant impact, primarily influenced by sulfur production. Human Toxicity Potential (HTP) follows as the second-worst contributor, with 96.80% of its impact attributed to heat and sulfur production. Subsequently, Acidification Potential (AP) follows, arising from sulfur and sulfuric acid production. Sensitivity analysis and Monte Carlo simulation introduce a ±20% standard deviation to electricity and thermal energy consumption. Scenario analysis demonstrates a net carbon-positive abatement potential of 286.66 kg CO2 eq. per tonne of CO2 input. Employing carbon mineralization for CO2 capture not only reduces emissions but also repurposes waste materials, providing a comprehensive and sustainable solution for effective CO2 management, contributing to reduced sand mining, and offering cost advantages through the production of carbonated RCA.

Research on Operation Characteristics of Passive Containment Heat Removal System in Typical Accident Conditions

In order to verify the feasibility of the design of the third generation of nuclear power plant independently developed in China, this study investigated the operation characteristics of the passive containment heat removal system under five working conditions using the passive containment heat removal system general performance verification facility: the design conditions, low water level conditions, low pressure conditions in the containment, extreme accidents conditions and resistance increasing conditions are analyzed, and the thermal characteristics, power requirements and thermal parameters of the containment under different operating conditions are analyzed. The results show that the heat dissipation capacity of the passive containment heat removal system exceeds the design requirements under the design conditions. Under off-design low pressure conditions, the pressure in the system is significantly affected. The decrease in the cooling water tank’s water level not only did not adversely affect the operation of the system but instead led to a significant increase in the system’s heat dissipation power. In the case of extreme accidents, the system may initially stall, but a stable natural cycle can then be established. As the system resistance coefficient increases, the heat dissipation power of the passive containment heat removal system exhibits an approximate linear decreasing trend.

Biophilia and Adolescents’ Sense of Place in Australian Vertical Schools

This article describes the place relationships adolescents have with natural elements in recently developed ‘vertical schools’ in Australia: a relatively new school typology in the country, generally considered to be over four storeys high. Vertical schools are being built in Australia’s largest cities in response to the need for new schools where land is scarce. Drawing on qualitative research into the place relationships that adolescents have with their learning environments in two Australian vertical schools, this article explores the ways young people seek closer associations with nature in multi-storey educational settings. The research adopted a phenomenological approach to ‘place research’, asking what makes a place a place? Further, it recognised that places have the capacity to shape the ‘becoming’ of a person, that ‘becoming’ happens when there is a certain resonance between a place’s cycles, and that identity is created out of difference. As such, ‘place as complex adaptive assemblage theory’ was employed to study the interplay between location and experience in selected vertical schools, also drawing on the earlier theoretical work of Relph (1976), who suggested that the essence of a place lies in the unselfconscious intentionality that defines places as profound centres of human existence. Photovoice was employed as a method to elicit insights into the relationships adolescents have with their school as place. Students created photo essays to document their place relationships, revealing deeply insightful personal reflections on their school as place and the meanings they associate with it. Specifically, the article reports on what thirteen adolescent students communicated about the biophilic experiences afforded by their vertical school, including how it influenced their ‘becoming’. The findings demonstrated that the participating students not only valued relationships with natural elements, but actively sought biophilic experiences on a regular basis. The desire for more frequent and more significant interactions with natural materials and cycles was common across most students, indicating that the relatively limited biophilic experiences available to students in vertical schools is a challenge that should be addressed in future multi-level educational environments.

Impact of overweight and obesity on live birth rate in single euploid frozen embryo transfers: the key is in the preparation protocol!

Research questionDoes endometrial preparation using a natural cycle (NC) lead to higher live birth rates (LBR) in single euploid frozen embryo transfers (seFET) compared to programmed cycles (PC), for women across normal, overweight, and obese body mass index (BMI) categories? DesignRetrospective study of 845 seFETs. Patients were stratified by BMI into 3 categories (Normal weight, Overweight, and Obesity Class I/II). Outcome was LBR. ResultsA total of 845 seFET cycles of 688 couples were included in the analysis. After achieving covariate (female age, AMH, embryo quality and infertility type) balance in each stratum, the effective sample size was 481 and 262 for the PC and NC, respectively. The PC approach, in which patients received vaginal luteal phase support with 3×100 mg micronized vaginal progesterone (MVP)/day, were associated with significantly lower LBR in the weighted regression analysis of the cohort (RR: 0.80, 95%CI: 0.73 – 0.88, p<0.001), compared to the NC approach. The effect was significantly modified by BMI (P=0.003). While the effect was significant for all BMI categories, the reduction in live birth was less pronounced in patients with normal or overweight BMI (RR: 0.87, 95%CI: 0.78-0.97, p=0.014) compared to patients with class I/II obesity (RR: 0.61, 95%CI: 0.49-0.75, p<0.001). ConclusionA natural cycle endometrial preparation approach leads to overall better live birth rates in single euploid FET, and the most significant difference is observed in women with higher BMI. Furthermore, overweight / obese patients in a PC may require a higher dosage of progesterone for luteal phase support.

Progesterone Concentrations on Blastocyst Transfer Day in Modified Natural Cycle Frozen Embryo Transfer Cycles

Progesterone Concentrations on Blastocyst Transfer Day in Modified Natural Cycle Frozen Embryo Transfer Cycles

Similar accuracy and patient experience with different one-step ovulation predictor kits

To examine the accuracy of five different at home ovulation predictor kits (OPKs), and to understand patient experience with the use of those kits. Prospective cohort study. Single academic fertility practice. Patients with regular menses undergoing monitored natural cycle frozen embryo transfer, timed intercourse, and intrauterine insemination cycles involving daily blood luteinizing hormone (LH) level monitoring between 2022 and 2024. Use of five commercially available OPKs for the first five days of blood LH monitoring with a daily experience survey. The primary outcome was accuracy of the ovulation predictor kits defined as concordance between test result (positive or negative) and blood LH level (above or below 25mIU/ml). Secondary outcomes included positive predictive value, negative predictive value, sensitivity, and specificity of OPK surge detection. We also examined patient report regarding clarity of kit instructions, confidence in kit results, and likelihood of future purchase and use. 23 patients completed 97 total days of ovulation predictor kit testing and 13 patients had a documented blood LH surge during their testing. OPK surge detection accuracy when compared to blood LH surge was similar across the five kits (Easy@Home 95.88%, Wondfo 94.85%, Pregmate 96.90%, Clearblue 91.75%, Clinical Guard 91.75%, p-value 0.06). Sensitivity was slightly better for Easy@ Home (75.00%), Wondfo (69.23%) and Pregmate (76.92%) than for Clearblue (61.54%) and Clinical Guard (38.46%). There were no clinically significant differences between the five OPKs regarding positive predictive value, negative predictive value, or specificity of surge detection. Participant experience was qualitatively similar across all five OPKs with exception of slightly fewer patients reporting that they were likely to purchase and use Clinical Guard again in the future. All five tested at home one step OPKs were highly accurate and performed similarly regarding patient experience despite variation in price.