Natural Cycle Research Articles

The impact of Artificial Light at Night (ALAN) on biodiversity: flora and fauna at Kebun Raya Bogor

Background: Artificial light at night (ALAN) poses significant ecological challenges by altering the natural light environment. Plants and animals have evolved to depend on natural light cycles for their physiological and behavioral processes. This study investigates the impact of ALAN on the biodiversity of flora and fauna at Kebun Raya Bogor (KRB), a key site for understanding these effects. Methods: This research employs a literature review approach to analyze the effects of ALAN on flora and fauna. By examining existing studies and data, the review focuses on changes in plant physiology, including photosynthesis and growth patterns, as well as alterations in animal behavior, such as foraging, mating, and migration. The review synthesizes findings from various sources to assess the impact of ALAN on biodiversity at KRB. Results: Findings indicate that ALAN disrupts plant photosynthesis and growth, particularly affecting deciduous trees and altering reproductive and growth patterns. For fauna, ALAN significantly impacts the behavior of nocturnal species such as bats and birds, affecting their feeding, mating, and migratory patterns. The disruption in natural light cycles due to ALAN leads to ecological imbalances and may compromise the biodiversity of KRB.

Harmonizing Nature, Education, Engineering and Creativity: An Interdisciplinary Educational Exploration of Engineered Living Materials, Artistry and Sustainability Using Collaborative Mycelium Brick Construction.

This study presents an innovative approach to interdisciplinary education by integrating biology, engineering and art principles to foster holistic learning experiences for middle-schoolers aged 11-12. The focus lies on assembling mycelium bricks as engineered living materials, with promising applications in sustainable construction. Through a collaborative group task, children engage in the hands-on creation of these bricks, gaining insights into mycology, biomaterials engineering and artistic expression. The curriculum introduces fundamental concepts of mycelial growth and its potential in sustainable material development. Children actively participate in fabricating 3D forms (negative and positive) using mycelium bricks, thereby gaining practical knowledge in shaping and moulding living materials. This hands-on experience enhances their understanding of biological processes and cultivates an appreciation for sustainable design principles. The group task encourages teamwork, problem-solving and creativity as children collaboratively compose structures using mycelium bricks. Integrating art into the activity adds a creative dimension, allowing participants to explore aesthetic aspects while reinforcing the project's interdisciplinary nature. Conversations about the material's end-of-life and decomposition are framed within the broader context of Nature's cycles, facilitating an understanding of sustainability. This interdisciplinary pedagogical approach provides a model for educators seeking to integrate diverse fields of knowledge into a cohesive and engaging learning experience. The study contributes to the emerging field of nature-inspired education, illustrating the potential of integrating living materials and 3D-understanding activities to nurture a holistic understanding of science, engineering and artistic expression in young learners.

Thermodynamic analysis of the air separation unit and CO2 purification unit in the semi-closed supercritical CO2 cycle with nearly zero emission

The natural gas-fired semi-closed supercritical CO2 cycle is an efficient oxyfuel combustion power generation technology featuring nearly zero emissions. This study investigated the interaction of the semi-closed supercritical CO2 power unit with the air separation unit (ASU), which supplies O2 for combustion and adiabatic compression heat for the heat recovery process in the power unit, and the CO2 purification unit (CPU), which refines the CO2 in the exhaust gas to 99.97% for enhanced oil recovery (EOR) applications. The detailed thermodynamic models of the power unit, ASU, and CPU have been constructed to explore the impact of variations in oxygen purity and excess oxygen coefficient on the overall thermodynamic performance of the system. The results demonstrate that the net electric efficiency peaks at an oxygen purity of 98%, and a one percent decrease in oxygen purity reduces the net electrical efficiency by approximately 0.36% to 0.97% points. Moreover, the net electric efficiency decreased by 0.10% points when the excess oxygen coefficient increased from 3.00% to 13.67%. These findings may offer valuable guidance for developing oxyfuel combustion power generation technologies.

Emotion and birth control: Emotion regulation ERPs differ based on menstrual cycle phase and hormonal contraceptive use

While hormonal contraceptives (HCs) like oral contraceptive pills (OCs) and intrauterine devices (IUDs) can reportedly influence mood, the evidence is mixed, and the mechanisms remain unclear. Emotion reactivity and regulation processes may be hormone-sensitive and underlie these mood changes. This study sought to investigate the role of the menstrual cycle and HC use in emotion regulation using ERP measures during an emotion regulation paradigm. Participants with a natural cycle (NC) were measured in the mid-follicular and mid-luteal phase (within-subject design, n = 26), and compared with OC (n = 36) and IUD (n = 25) users. The centroparietal late positive potential (LPP) reflected negative emotion reactivity and its modulation by cognitive reappraisal served as a marker for emotion regulation processing. NC participants had a lower LPP amplitude in the mid-luteal compared to the mid-follicular phase. Reactivity to negative emotional stimuli decreased over time in the mid-luteal phase, whereas the HC groups showed sustained LPP activation. Reappraisal led only to significant LPP changes in the mid-follicular phase, and not in the mid-luteal phase or HC groups. Our results showed a specific left frontal activity (FR-LPP) in the contrast that reflected emotion regulation processing. This activity was highest in the mid-follicular phase, and was significantly different from the OC users but not from the IUD group. Higher self-reported PMS symptoms were associated with stronger effects on the reduced mid-luteal LPP activity and with lower FR-LPP amplitude in the mid-follicular phase. No effect of OC phase (active pill use versus pill pause) was found. These findings add insights into the neurophysiological underpinnings of hormone-related mood changes and demonstrate the importance of considering hormonal status and PMS symptoms in emotion research.

Electrochemical membrane systems for remediating ammonium-containing wastewater via coupling capacitance adsorption and oxygen reduction

As the main nitrogen-containing pollutant of industrial and agricultural wastewater, ammonium (NH4+) is obtainable from the natural nitrogen cycle and industrial emission. Electrochemical recovering nitrogen (N) from nitrate-polluted wastewater to produce ammonia (NH3) is a promising route to mitigate pollution risks and create economic values. Since side reactions at the electrodes are inevitable, and the competition mechanism between electric double layer capacitance (EDLC) behavior and side reactions is still unclear. Herein, electrochemical selective NH4+ recovery from wastewater was achieved by coupling NH4+ adsorption and side oxygen reduction reaction (ORR) in a novel electrochemical membrane extraction system using Ti3C2TX-based gas-diffusion cathodes. Batch experiments showcase simultaneous NH4+ removal and recovery, with TiOX/TiC-C exhibiting the highest removal capability of 408 mgN g−1. In situ Raman spectroscopy revealed the critical role of the four-electron transfer ORR reaction in the conversion of NH4+ to NH3. Density functional theory (DFT) showed that excellent electron-donating ability for NH4+ of TiOX/TiC-C electrode (1.97 eV) facilitated NH4+ diffusion onto electrode interface. The study sheds light on the intricate interplay between NH4+ adsorption and ORR, highlighting the significance of tailored support and vacancy engineering in advancing wastewater treatment and resource recovery.

Temporalities of oxytocin for labour augmentation: a mixed-methods study of time factors shaping labour practices in a busy maternity unit in Tanzania

BackgroundHigh rates of labour augmentation with oxytocin have been found in some low- and lower-middle-income countries, causing potential perinatal harm. It is critical to understand the reasons for this overuse. Aim was to explore factors that shape practices around using oxytocin for labour augmentation in a high-volume labour ward in Dar es Salaam, Tanzania.MethodsMixed-methods data collection was conducted from March 2021 to February 2022, including structured observations of 234 births, 220 h of unstructured labour ward observations and 13 individual in-depth interviews with birth attendants. Thematic network analysis and descriptive statistics were used to analyse data. We used a time-lens to understand practices of oxytocin for labour augmentation in time-pressured labour wards.ResultsBirth attendants constantly had to prioritise certain care practices over others in response to time pressure. This led to overuse of oxytocin for augmentation to ensure faster labour progression and decongestion of the, often overburdened, ward. Simultaneously, birth attendants had little time to monitor foetal and maternal condition. Surprisingly, while oxytocin was used in 146 out of 234 (62.4%) structured labour observations, only 9/234 (4.2%) women had active labour lasting more than 12 h. Correspondingly, 21/48 (43.8%) women who were augmented with oxytocin in the first stage of labour had uncomplicated labour progression at the start of augmentation. While the partograph was often not used for decision-making, timing of starting oxytocin often correlated with natural cycles of ward-rounds and shift-turnovers instead of individual women’s labour progression. This resulted in co-existence of ‘too early’ and ‘too late’ use of oxytocin. Liberal use of oxytocin for labour augmentation was facilitated by an underlying fear of prolonged labour and low alertness of oxytocin-related risks.ConclusionsTime scarcity in the labour ward often made birth attendants deviate from clinical guidelines for labour augmentation with oxytocin. Efforts to navigate time pressure resulted in too many women with uncomplicated labour progression receiving oxytocin with little monitoring of labour. Fear of prolonged labour and low alertness to oxytocin-mediated risks were crucial drivers. These findings call for research into safety and benefits of oxytocin in low-resource settings and interventions to address congestion in labour wards to prevent using oxytocin as a time-management tool.

Political Economic Role in Natural Quality Management and its Impact on Plant Ecology: Why Arar-Juniper Plants Disappeared

Wadi-Arar is a unique region that has lost some of its most important natural features within 200 years, including plants, geographical lakes, and valleys. The study aimed to investigate the disappearance of the juniper plant, a vital species in Saudi Arabia, in recent decades. The research highlighted various factors influencing the quality of life for the juniper plant and its habitats. It sought to identify the primary factors causing changes in the natural conditions of the plant and those influencing its growth. The findings indicated a significant impact of the Suez Canal on the Arar region, the sole connection between Africa and Asia, and Europe. This influence extends beyond geopolitical factors in the surrounding area, as the existence of the Suez Canal disrupted the natural life cycle of many animal species over thousands of years of migrations and coexistence across Earth's continents. These animals previously provided natural organic fertilizer to the soil, supporting plant growth. However, due to low rainfall resulting in low natural nutrients and high salinity, the plants' viability has diminished, reflecting a history of administrative and geopolitical decisions.

Comparative assessment of fluoride and arsenic mobilization mechanisms among the groundwater of the major affected river basins of India

ABSTRACT The high exposure of fluoride and arsenic in the groundwater of India is a serious challenge that is currently threatening human health, agriculture, livestock, and livelihood. The increased dependency on groundwater due to monsoonal uncertainties amplifies the risk by several folds. Due to the high population density in the affected regions, policies on prevention, monitoring, and mitigation have become extremely challenging to implement. The pursuit of improved human health in the affected regions cannot be completed until and unless there is sufficient urbanization and industrialization to support the livelihood, which again aggravates the situation due to improper disposal of anthropogenic contaminants owing to the lack of knowledge about the natural cycle of contaminants. The present review article is an attempt to understand the problem of fluoride and arsenic in the scenario of Indian floodplains by first explaining the globally identified mobilization mechanisms of these contaminants and then developing a compendium of knowledge through which the risk on the Indian floodplains can be analysed. Then the study compares the similarity/dissimilarity in the enrichment mechanism followed by a detailed investigation of the available mitigation techniques. In totality, the present study adds a new dimension to our understanding of the risk due to contaminants.

Is there an association between the ‘October 7th’ events and IVF outcomes in Israel?

Research questionIs there an association between the ‘October 7th’ 2023 events and IVF outcomes in Israel? Designin this retrospective cohort study the study group was women treated during the 4 weeks after ‘October 7th’, compared with a matched control group treated between 1 January 2021 and 6 October 2023. Each study group participant was matched with three separate control subjects of the same female age at oocyte retrieval, with a matching body mass index (BMI), IVF cycle number and ovarian reserve parameters. ResultsThe study included 580 patients. The 145 women who underwent oocyte retrieval or frozen embryo transfer after 7 October 2023 were compared with 435 women treated before 7 October. The mean age of the study group was 35.6 ± 6 years, and the mean BMI 24.7 ± 5.3 kg/m2. Pregnancy rates per embryo transfer were similar between the groups (22.4% versus 30.5%, P = 0.28 in fresh cycles; 16.9% versus 27.1%, P = 0.12 in frozen embryo transfers). Among women who underwent oocyte retrieval there were no differences in the ovarian stimulation protocols (P = 0.95), number of oocytes retrieved (P = 0.16) or number of fertilized oocytes (P = 0.34). There was no difference in the rate of good-quality embryos between groups (P = 0.053). Among women who underwent frozen embryo transfers, during the study period more patients had natural cycles (52.5% versus 24%, P < 0.001), and there was no difference in maximal endometrial thickness before embryo transfer (P = 0.33). ConclusionsIt appears that there is no association between the ‘October 7’ events and IVF outcomes.

Measuring the Surface Tension of Atmospheric Particles and Relevant Mixtures to Better Understand Key Atmospheric Processes.

Aerosol and aqueous particles are ubiquitous in Earth's atmosphere and play key roles in geochemical processes such as natural chemical cycles, cloud and fog formation, air pollution, visibility, climate forcing, etc. The surface tension of atmospheric particles can affect their size distribution, condensational growth, evaporation, and exchange of chemicals with the atmosphere, which, in turn, are important in the above-mentioned geochemical processes. However, because measuring this quantity is challenging, its role in atmospheric processes was dismissed for decades. Over the last 15 years, this field of research has seen some tremendous developments and is rapidly evolving. This review presents the state-of-the-art of this subject focusing on the experimental approaches. It also presents a unique inventory of experimental adsorption isotherms for over 130 mixtures of organic compounds in water of relevance for model development and validation. Potential future areas of research seeking to better determine the surface tension of atmospheric particles, better constrain laboratory investigations, or better understand the role of surface tension in various atmospheric processes, are discussed. We hope that this review appeals not only to atmospheric scientists but also to researchers from other fields, who could help identify new approaches and solutions to the current challenges.

Multifunctional silver nanoparticle embedded eri silk cocoon scaffolds against burn wounds-associated infection.

Antimicrobial wound dressings offer enhanced efficacy compared to conventional dressing platforms by limiting bacterial infections, expediting the healing process, and creating a barrier against additional wound contamination. The use of silk derived from silkworm cocoons in wound healing applications is attributed to its exceptional characteristics. Compared to mulberry silk, sericin from non-mulberry cocoons has higher water exchange mobility and moisture retention. Eri, a non-mulberry silkworm, is an unexplored source of silk with an eco-friendly nature of production where the natural life cycle of silkworms is not disrupted, and no moths are sacrificed. This work reports on an eri silk cocoon-based scaffold decorated with silver nanoparticles as a wound dressing material effective against burn-wound-associated multiple-drug-resistant bacteria. The UV-vis spectroscopy showed maximum absorbance at 448 nm due to the surface plasmon resonance of silver nanoparticles. FT-IR spectra exhibited the functional groups in the eri silk proteins accountable for the reduction of Ag+ to Ag0 in the scaffold. SEM-EDX analysis revealed the presence of elemental silver, and XRD analysis confirmed their particle size of 5.66-8.82 nm. The wound dressing platform showed excellent thermal stability and hydrophobicity, fulfilling the criteria of a standard waterproof dressing material, and anticipating the prevention of bacterial biofilm formation in chronic wounds. The scaffold was found to be effective against both Staphylococcus aureus (MTCC 87) and Pseudomonas aeruginosa (MTCC 1688) multiple-drug-resistant pathogens. Electron microscopy revealed the bacterial cell damage, suggesting its bactericidal property. The results further revealed that the scaffold was both hemocompatible and cytocompatible, suggesting its potential application in chronic wounds such as burns. As an outcome, this study presents a straightforward, cost-effective, and sustainable way of developing a multifunctional wound dressing platform, suggesting its significant therapeutic potential in clinical and biomedical sectors and facile commercialization.

Hydrovoltaic Effects from Mechanical-Electric Coupling at the Water-Solid Interface.

The natural water cycle on the Earth carries an enormous amount of energy as thirty-five percent of solar energy reaching the Earth's surface goes into water. However, only a very marginal part of the contained energy, mostly kinetic energy of large volume bulk water, is harvested by hydroelectric power plants. Natural processes in the water cycle, such as rainfall, water evaporation, and moisture adsorption, are widespread but have remained underexploited in the past due to the lack of appropriate technologies. In the past decade, the emergence of hydrovoltaic technology has provided ever-increasing opportunities to extend the technical capability for energy harvesting from the water cycle. Featuring electricity generation from mechanical-electric coupling at the water-solid interface, hydrovoltaic technology embraces almost all dynamic processes associated with water, including raining, waving, flowing, evaporating, and moisture adsorbing. This versatility in dealing with various forms of water and associated energy renders hydrovoltaic technology a solution for fossil fuel-caused environmental problems. Here, we review the current progress of hydrovoltaic energy harvesting from water motion, evaporation, and ambient moisture. Device configuration, energy conversion mechanism mediated by mechanical-electric coupling at various water-solid interfaces, as well as materials selection and functionalization are discussed. Useful strategies guided by established mechanisms for device optimization are then covered. Finally, we provide an outlook on this emerging field and outline the challenges of improving output performance toward potential practical applications.

Mapping Topic Evolution across the 40-Year-Old Long-Term Ecological Research MareChiara Site in the Gulf of Naples, Italy

The forty-year-old Long-Term Ecological Research MareChiara (LTER-MC) program started on 26 January 1984, with fortnightly oceanographic sampling until 1991 and then, from 1995, with weekly sampling up to the present time. LTER-MC produced &gt;150 publications that have been cited by thousands of other studies. In this scoping review, we analyzed this corpus using a semantic approach based on topic modeling, a machine-driven procedure to identify and map topics and their interactions. Understanding the causes behind the evolution of scientific topics, their emergence, splitting, hybridization, or merging within a scientific community is an important step in science policy in managing collaborative research and bringing it into the future. Across different topics, mainly represented by studies on Natural History, Biodiversity, Phenology, Life Cycles, and Community Ecology, the LTER-MC work expanded the knowledge on planktonic organisms, describing in detail their lifestyles and delineating their relationships with environmental conditions. In presenting these results, the potential strengths, weaknesses, opportunities, and threats connected to the overall scientific dimension of LTER-MC are discussed. Finally, the upcoming effort is envisioned in reinforcing internal collaboration to integrate basic and applied research around scientific investigations suitable for establishing a stronger interaction between science and policy, as indicated by the United Nations Decade of Ocean Science for Sustainable Development.

Corporate credit mismatch, financial leverage and corporate investment efficiency

We empirically test the relationship between credit mismatch and corporate investment efficiency. The study analyzes the heterogeneity of mismatch direction, corporate nature, and corporate life cycle. Results reveal that corporate credit mismatch has a significant negative impact on corporate investment efficiency; corporate financial leverage fully mediates this impact, indicating that corporations may increase their financial leverage to bridge financing gaps in cases of credit mismatch. This practice, however, may bring about greater financial risk and affect corporate investment efficiency. This study provides an important reference for enterprises and financial institutions for optimizing the financing environment, ensuring the effective allocation of financing resources, promoting the sustainable development of enterprises, thereby enhancing overall economic efficiency. This study also provides new ideas and future directions for studying corporate financing and investment behavior.

Investigating Different Interpolation Methods for High-Accuracy VTEC Analysis in Ionospheric Research

The dynamic structure of the ionosphere and its changes play an important role in comprehending the natural cycle by linking earth sciences and space sciences. Ionosphere research includes a variety of fields like meteorology, radio wave reflection from the atmosphere, atmospheric anomaly detection, the impact on GNSS (Global Navigation Satellite Systems) signals, the exploration of earthquake precursors, and the formation of the northern lights. To gain further insight into this layer and to monitor variations in the total electron content (TEC), ionospheric maps are created using a variety of data sources, including satellite sensors, GNSS data, and ionosonde data. In these maps, data deficiencies are addressed by using interpolation methods. The objective of this study was to obtain high-accuracy VTEC (Vertical Total Electron Content) information to analyze TEC anomalies as precursors to earthquakes. We propose an innovative approach: employing alternative mathematical surfaces for VTEC calculations, leading to enhanced change analytical interpretation for anomaly detections. Within the scope of the application, the second-degree polynomial method, kriging (point and block model), the radial basis multiquadric, and the thin plate spline (TPS) methods were implemented as interpolation methods. During a 49-day period, the TEC values were computed at three different IGS stations, generating 1176 hourly grids for each interpolation model. As reference data, the ionospheric maps produced by the CODE (Center for Orbit Determination in Europe) Analysis Center were used. This study’s findings showed that, based on statistical values, the TPS model offered more accurate results than other methods. Additionally, it has been observed that the peak values in TEC calculations based on polynomial surfaces are eliminated in TPSs.

Deciphering the importance of morphological aspects in drought tolerance in eucalyptus progenies

Water limitation is one of the factors that most impact plant growth and productivity, especially for Eucalyptus. For commercial eucalyptus plantations to develop properly, it is essential to select clones with drought-tolerant characteristics, especially in areas with low rainfall and well-defined dry periods. Accordingly, climate change, mainly related to increases in mean annual temperature, can lead to a more severe water deficit and ultimately harm plant development. Thus, the identification of indicators related to climatic variables enables the selection of clones with drought tolerance characteristics. Here, we used 27 families of eucalyptus progenies from crosses of plants with previously selected characteristics associated with drought tolerance, which were planted in a region characterized by high water deficiency. Sample harvesting was performed at 6, 18, and 30 months after planting, at the end of natural drought cycles. Meteorological data coupled with physiological analyses allow the early selection of Eucalyptus clones that are better able to tolerate recurrent drought events. Specific leaf area (SLA), leaf area (LA), length (L), width (W), and leaf water potential (ΨL) were analyzed. The parameters SLA, LA, and ΨL proved to be good bioindicators of Eucalyptus drought tolerance. Specific clones and progenies (e.g., GG2673, VM1, GG1923, GG1980, GG3389XGG4302, GG918XVS62, AEC2034xLR831, I3000XVM1, VM4XCAM, and VM1xVM4) were characterized by physiological adjustments and showed higher average annual volumetric increment (IMAvol) values and were assumed as genetic materials with potential drought tolerance.

Assessment of the influence of natural thermal cycles on dolomitic limestone rock columns: A 10-year monitoring study

Rock instabilities hazards can lead to major risks. Even if different external factors such as precipitation, seismic activity or freezing, are known to trigger rockfalls, it is more and more assumed that thermal cycling has a role in rock mass deformation, displacement and, moreover cracking initiation or propagation. Here we present 10 years monitoring of a 50-meter-high dolomitic cliff, located above an important highway in the south of France to support this thinking. Local rock surface temperature and joint apertures were recorded on eleven sensors. Their evolution is studied separately and together to characterise the influence of temperature variation on joint apertures. During small time periods, a reversible and proportional behaviour is observed, that can be attributed to thermoelasticity, but over the whole period, a significant drift in displacements is measured, meaning that at least a viscoplastic or fatigue behaviour should be considered.

Use of hCG for luteal support in natural frozen-thawed blastocyst transfer cycles: a cohort study.

In the realm of natural frozen-thawed embryo transfer (FET) cycles, the application of luteal phase support (LPS) is a prevalent practice, primarily due to its beneficial impact on reproductive outcomes. Among the various LPS medications, human chorionic gonadotropin (hCG) is one that exerts its function on both the corpus luteum and the endometrium. To evaluate the effect of hCG administration as LPS on reproductive outcomes in natural FET cycles. This study was a retrospective cohort analysis conducted at a tertiary care hospital. It included women who underwent natural FET treatment from January 2018 to December 2022. Participants were divided into the hCG LPS group and the non-hCG LPS group on the basis of whether they used hCG as LPS after blastocyst transfer. The primary outcome was the clinical pregnancy and live birth rates. The secondary outcomes included the early miscarriage rate (before 12th gestational week) and total miscarriage rate. A total of 4762 women were included in the analysis, and 1910 received hCG LPS and 2852 received no hCG LPS (control group). In the general cohort, the clinical pregnancy and live birth rates in the hCG LPS group were significantly lower than those in the control group (63.82% vs 66.41%, aOR 0.872, 95% CI 0.765-0.996, P=0.046; 53.98% vs 57.15%, aOR 0.873, 95% CI 0.766-0.991, P=0.035, respectively). The early miscarriage and total miscarriage rates were similar between the two groups. In a subgroup analysis, in women who received an hCG trigger, there was no significant difference in the clinical pregnancy rate or live birth rate between the two groups. However, in women who ovulated spontaneously, the clinical pregnancy and live birth rates in the hCG LPS group were significantly lower than those in the control group (60.99% vs 67.21%, aOR 0.786, 95% CI 0.652-0.946, P=0.011; 50.56% vs 57.63%, aOR 0.743, 95% CI 0.619-0.878, P=0.001, respectively). Among women undergoing natural cycle frozen-thawed blastocyst transfer, hCG LPS is associated with lower clinical pregnancy and live birth rates. Additionally, the adverse effect of hCG LPS is more pronounced in women who ovulate spontaneously.

Aging promotes accumulation of senescent and multiciliated cells in human endometrial epithelium.

What changes occur in the endometrium during aging, and do they impact fertility? Both the transcriptome and cellular composition of endometrial samples from women of advanced maternal age (AMA) are significantly different from that of samples from young women, suggesting specific changes in epithelial cells that may affect endometrial receptivity. Aging is associated with the accumulation of senescent cells in aging tissues. Reproductive aging is mostly attributed to the decline in ovarian reserve and oocyte quality, whereas the endometrium is a unique complex tissue that is monthly renewed under hormonal regulation. Several clinical studies have reported lower implantation and pregnancy rates in oocyte recipients of AMA during IVF. Molecular studies have indicated the presence of specific mutations within the epithelial cells of AMA endometrium, along with altered gene expression of bulk endometrial tissue. Endometrial transcriptome profiling was performed for 44 women undergoing HRT during the assessment of endometrial receptivity before IVF. Patients younger than 28 years were considered as the young maternal age (YMA) group (age 23-27 years) and women older than 45 years were considered as the AMA group (age 47-50 years). Endometrial biopsies were obtained on Day 5 of progesterone treatment and RNA was extracted. All endometrial samples were evaluated as being receptive based on the expression of 68 common endometrial receptivity markers. Endometrial samples from another 24 women classified into four age groups (YMA, intermediate age group 1 (IMA1, age 29-35), intermediate age group 2 (IMA2, age 36-44), and AMA) were obtained in the mid-secretory stage of a natural cycle (NC) and used for validation studies across the reproductive lifespan. A total of 24 HRT samples (12 YMA and 12 AMA) were subject to RNA sequencing (RNA-seq) and differential gene expression analysis, 20 samples (10 YMA and 10 AMA) were used for qPCR validation, and 24 NC samples (6 YMA, 6 IMA1, 6 IMA2 and 6AMA) were used for RNA-seq validation of AMA genes across the woman's reproductive lifespan. Immunohistochemistry (IHC) was used to confirm some expression changes at the protein level. Computational deconvolution using six endometrial cell type-specific transcriptomic profiles was conducted to compare the cellular composition between the groups. Comparisons between YMA and AMA samples identified a lower proportion of receptive endometria in the AMA group (P = 0.007). Gene expression profiling identified 491 differentially expressed age-sensitive genes (P adj < 0.05) that revealed the effects of age on endometrial epithelial growth and receptivity, likely contributing to decreased reproductive performance. Our results indicate that changes in the expression of the cellular senescence marker p16INK4a and genes associated with metabolism, inflammation, and hormone response are involved in endometrial aging. Importantly, we demonstrate that the proportion of multi-ciliated cells, as discovered based on RNA-seq data deconvolution and tissue IHC results, is affected by endometrial aging, and propose a putative onset of age-related changes. Furthermore, we propose that aging has an impact on the transcriptomic profile of endometrial tissue in the context of endometrial receptivity. The raw sequencing data reported in this article are deposited at the Gene Expression Omnibus under accession code GSE236128. This retrospective study identified changes in the endometrium of patients undergoing hormonal replacement and validated these changes using samples obtained during a NC. However, future studies must clarify the importance of these findings on the clinical outcomes of assisted reproduction. The findings reported in this study have important implications for devising future strategies aimed at improving fertility management in women of advanced reproductive age. This research was funded by the Estonian Research Council (grant no. PRG1076), Horizon 2020 innovation grant (ERIN, grant no. EU952516), Enterprise Estonia (grant no. EU48695), MSCA-RISE-2020 project TRENDO (grant no. 101008193), EU 874867 project HUTER, the Horizon Europe NESTOR grant (grant no. 101120075) of the European Commission, the EVA specialty program (grant no. KP111513) of the Maastricht University Medical Center (MUMC+), MICIU/AEI/10.13039/501100011033 and FEDER, EU projects Endo-Map (grant no. PID2021-12728OB-100), ROSY (grant no. CNS2022-135999), and the National Science Fund of Bulgaria (grant no. KII-06 H31/2). The authors declare no competing interests.

Trivariate copula functions for constructing a comprehensive atmosphere-land surface-hydrology drought index: A case study in the Yellow River basin

The current univariate and multivariate drought indices cannot fully reflect the multiple processes of meteorological-hydrological-agricultural drought. So it is important to construct a comprehensive drought index for drought monitoring in a changing environment from the perspective of the whole process of the natural water cycle “atmosphere-land surface-hydrology”. In this study, based on the standardized indices (SCI) framework and trivariate Copula functions, a multi-scale comprehensive drought index (SPERSI) integrating rainfall, temperature, runoff and soil moisture is proposed, which can synthetically reflect meteorological, hydrological and agricultural droughts. The spatial and temporal variations of drought in the Yellow River Basin (YRB) from 1961 to 2019 were investigated, and then the links between SPERSI and some remotely correlated factors were revealed by using the multiple cross wavelet transform technique. Results show that: (1) the SPERSI constructed by fusing rainfall-temperature-runoff-soil moisture information can sensitively and effectively capture the onset, persistence and termination of drought; (2) the SPERSI exhibits good performance in detecting integrated drought events in the YRB with probability of detection (POD) > 0.75, false alarm rate (FAR) < 0.04 and critical success index (CSI) > 0.73; (3) From 1961 to 2019, drought in different time scales of above Longyangxia (AL) and Longyangxia to Lanzhou (LL) zones in the YRB both show a slight mitigation trend, while the drought in remaining subzones show a trend of intensification; (4) Multiple cross-wavelet results indicate that AO is the dominant factor of drought in the Yellow River Basin, followed by ENSO. In general, SPERSI results are reliable and can provide basis for drought decision-making.