The application of scanning near field optical imaging to the study of human sperm morphology

BackgroundThe morphology of spermatozoa is a fundamental aspect to consider in fertilization, sperm pathology, assisted reproduction and contraception. Head, neck, midpiece, principal and terminal part of flagellum are the main sperm components to investigate for identifying morphological features and related anomalies. Recently, scanning near-field optical microscopy (SNOM), which belongs to the wide family of nanoscopic techniques, has opened up new routes for the investigation of biological systems. SNOM is the only technique able to provide simultaneously highly resolved topography and optical images with a resolution beyond the diffraction limit, typical of conventional optical microscopy. This offers the advantage to obtain complementary information about cell surface and cytoplasmatic structures.ResultsIn this work human spermatozoa both healthy and with morphological anomalies are analyzed by SNOM, to demonstrate the potentiality of such approach in the visualization of sperm morphological details. The combination of SNOM topography with optical (reflection and transmission) images enables to examine typical topographic features of spermatozoa together with underlying cytoplasmic structures. Indeed the head shape and inner components as acrosome and nucleus, and the organization of mitochondria in the midpiece region are observed. Analogously for principal tract of the tail, the ridges and the columns are detected in the SNOM topography, while their internal arrangement can be observed in the corresponding SNOM optical transmission images, without requiring specific staining procedures or invasive protocols.ConclusionsSuch findings demonstrate that SNOM represents a versatile and powerful tool to describe topographical and inner structural details of spermatozoa simultaneously. This analysis could be helpful for better characterizing several morphological anomalies, often related to sperm infertility, which cannot be examined by conventional techniques all together

Agronomic-productive Characteristics of Two Genotype of Stevia Rebaudiana in Central Italy

Stevia rebaudiana Bertoni produces a variety of high-potency low calorie sweeteners in its' leaf tissue. The aim of this work was to evaluate the productive potential of two different Stevia rebaudiana genotypes and the characteristics of the production of the plant obtained through different cultivation methods, in central Italy. For several years (1992-2000) agronomic trials on Stevia rebaudiana cultivated in the littoral area near Pisa (Italy) carried out. In 1992 two different genotypes of Stevia (B1 and B2) transplanted in silt-loam soil; in 1996 other plants from B2 genotype, produced by vegetative process (micropropagation), were transplanted in the same field. In the period from 1992-1999 the production of leaves from both genotypes increase as of the third year and the ratio leaf-aerial plant, after the peak in the third year, tends to diminish. Except the first year (1997) there were not recorded statistically significant differences between the two propagation methods employed in relation to leaf production. The quantity of leaves produced from a single harvest was less than resulting from two cuttings and the micropropagation plants produced a larger amount of leaves than those from cutting. The leaf-stem ratio was to become an interesting morphological and production characteristic parameter of the plant. Stevia rebaudiana appears particularly suited for the cultivation environment of central Italy. A particular positive aspect that must be considered in these regions is that Stevia can be grown successfully as poliannual species because crop survival over the winter is high. The results obtained show that this species is economically profitable until the 5th or 6th year of cultivation. At our latitudes is also necessary to establish a program of genetic improvement in order to develop earlier varieties that can guaranty an optimum qualitative and quantitative seed production

Digitalizing Whom? On the Early Adopters of Smart Energy Technology

editorial reviewedU-AGR-7257 - BRIDGES/2022/IS/17742284/FlexBeAM - FRIDGEN Gilbert9. Industry, innovation and infrastructur

From Awareness to Action: Energy Literacy and Household Energy Use

peer reviewe

AFM macro-probes to investigate whole 3D cardiac spheroids

In its many applications, the Atomic Force Microscope (AFM) is a promising tool in cardiac mechanobiology because it can unravel the viscoelastic and mechano-dynamic properties of individual cardiomyocytes. However, the biophysical investigation of more accurate 3D models is hampered by commercial probes, which typically operate at the cell sub-compartmental resolution. We have previously shown how flat macro-probes can overcome these limitations by extending the AFM mechanical measurements to multicellular aggregates. Such macro-probes are fabricated by standard micromachining and carry a flat polymeric wedge to offset the AFM mounting tilt. Therefore, the AFM is upgraded to a micro-parallel plate rheometer with unmatched force range and sensitivity. In this article, we show how these macro-probes can be applied to reveal the global rheology of primary cardiomyocytes spheroids, by performing stress-relaxation tests. More importantly, we demonstrate that these macro-probes can be used as passive sensors capable of monitoring the spheroid beating force and beating pattern, and to perform a “micro-CPR” on the spheroid itself

The Residential Perception of Real-time Electricity Tariffs

peer reviewedThis study explores household perceptions of realtime pricing tariffs, focusing on the influence of energy-related financial literacy and perceived tariff complexity. We conducted a large-scale survey with 1,005 participants in a small European country and analyzed the results using hierarchical multiple regression. Our findings indicate that higher financial literacy correlates with increased perceptions of risks over benefits toward real-time pricing tariffs. However, perceived complexity significantly influences this relationship, reducing the impact of financial literacy. Additionally, demographic factors, including photovoltaic ownership, education level, age, and gender, play significant roles in shaping perceptions. We highlight the importance of simplifying real-time pricing tariffs or providing supportive technologies to enhance consumer acceptance. These insights challenge conventional assumptions about energy literacy and suggest that addressing perceived tariff complexity is crucial for aligning consumer behavior with the goals of the green energy transition.7. Affordable and clean energy9. Industry, innovation and infrastructure11. Sustainable cities and communitie

The local mechanosensitive response of primary cardiac fibroblasts is influenced by the microenvironment mechanics

Cardiac fibroblasts (CFs) are essential for preserving myocardial integrity and function. They can detect variations in cardiac tissue stiffness using various cellular mechanosensors, including the Ca2+ permeable mechanosensitive channel Piezo1. Nevertheless, how CFs adapt the mechanosensitive response to stiffness changes remains unclear. In this work we adopted a multimodal approach, combining the local mechanical stimulation (from 10 pN to 350 nN) with variations of culture substrate stiffness. We found that primary rat CFs cultured on stiff (GPa) substrates showed a broad Piezo1 distribution in the cell with particular accumulation at the mitochondria membrane. CFs displayed a force-dependent behavior in both calcium uptake and channel activation probability, showing a threshold at 300 nN, which involves both cytosolic and mitochondrial Ca2+ mobilization. This trend decreases as the myofibroblast phenotype within the cell population increases, following a possible Piezo1 accumulation at focal adhesion sites. In contrast, the inhibition of fibroblasts to myofibroblasts transition with soft substrates (kPa) considerably reduces both mechanically- and chemically-induced Piezo1 activation and expression. Our findings shed light on how Piezo1 function and expression are regulated by the substrate stiffness and highlight its involvement in the environment-mediated modulation of CFs mechanosensitivity

Atomic force spectroscopy-based essay to evaluate oocyte postovulatory aging

Postovulatory aging is a process occurring in the mature (MII) oocyte leading the unfertilized ones to apoptosis. The optimal time window of fertility for different mammalian species after oocytes maturation depends on its timeliness: the higher the time elapsed from the accomplishment of the MII stage, the lower are the chances of fertilization and of development of a viable embryo. In the in vitro fertilization, the selection of competent oocytes for intracytoplasmic sperm injection (ICSI) is mostly made by the visual inspection of the MII oocyte morphology, which does not allow to determine the oocyte postovulatory age. On the other hand, more specific tests usually involve some kind of staining, thus compromising the viability of the oocyte for reproductive purposes. Hence, the need of a noninvasive analysis of oocyte aging to improve the success rate of in vitro fertilization procedures. Here, we exploit atomic force microscopy to examine the evolution of the mechanical properties of mouse oocytes during in vitro postovulatory aging. Three hours before the occurrence of any visual morphological feature related to degradation, we observe a sudden change of the mechanical parameters: the elastic modulus doubles its initial value, while the viscosity decreases significantly. These mechanical variations are temporally correlated with the release of the cortical granules, investigated by fluorescence microscopy. Interestingly, the oocyte mechanics correlates as well with the yield of embryo formation, evaluated up to the blastocyst formation stage. These results demonstrate that minimally invasive mechanical measurements are very sensitive to the aging of the oocyte and can be used as a label-free method to detect the age of the postovulatory oocytes

Effects of Temperature, Light and Pre-Chilling on Seed Germination of Stevia rebaudiana (Bertoni) Bertoni Accessions

Stevia rebaudiana (Bertoni) Bertoni is a perennial shrub of the Asteraceae family native to Paraguay and Brazil where it has been used for several years as a sweetener. It is a short-day species, with a critical light requirement for flowering of roughly 13 hours. In plants whose biological cycle is strongly photoperiod-dependent, latitude is one of the major factors influencing reproduction. Late flowering may adversely affect seed production if this occurs during a season that is unfavorable to pollination. At Italian latitudes, this species often gives scanty seed production, with low germination rate and poor germination energy of seeds produced. In 2001 four accessions have been grown for seed production in a field plot experiment in Central Italy. The various accessions were found to exhibit noticeably different photoperiod requirements, which affected flowering time (from late August to the end of September) and consequently also the conditions of achene filling and ripening. Late flowering and seed ripening occurred during autumn season, unfavourable to complete seed formation, leading to an increase in the empty seed percentage recorded for each accession. Detailed germination trials were therefore undertaken using seeds collected from plants of the different accessions in order to assess the quality of the seeds produced. Various germination methods have been tested in a controlled environment adopting four different temperatures (20° C, 25° C constant temperature and 15/25° C, 20/30° C (16/8h) alternating temperature) in light or darkness with or without pre-chilling. Germination rates varied over an extensive range (germination percentage from 9 to 83%), mainly due to the divergent specific characteristics of the material examined and the different treatments studied. At all temperatures tested, the most earlier accession, showed the higher germination percentages (54-83%) while the latest accession was among those with the lowest germination values (9-44%). Overall, at the constant temperatures assayed, pre-chilling gave a higher germination percentage as compared to no pre-chilling, while at alternating temperatures higher germination rates were obtained in the absence of pre-chilling. The great variability observed between accessions for photoperiodic requirement as well as in seed germinative characteristics was probably due to the fact that this species was not subjected to any genetic improvement program