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Το αντικείμενο της έρευνας αυτής είναι η μελέτη των φαινομένων μεταφοράς θερμότητας καιμάζας μεταξύ του αέρα, του αφυγραντικού υλικού και του νερού που συντελούνται στακλιματιστικά συστήματα ανοικτού εξατμιστικού κύκλου με υγρά προσροφητικά υλικά. Ηέρευνα υλοποιείται τόσο σε θεωρητικό όσο και σε πειραματικό επίπεδο και εξετάζει τηνενεργειακή απόδοση του αφυγραντή και του αναγεννητή. Αρχικά, αποκτάται το θεωρητικόυπόβαθρο σχετικά με τις θερμοδυναμικές ιδιότητες των πιο διαδεδομένων αφυγραντικώνυδατικών διαλυμάτων (Χλωριούχο Λίθιο, Βρωμιούχο Λίθιο, Χλωριούχο Ασβέστιο). Η γνώσηαυτή χρησιμοποιείται ως βάση για την ανάπτυξη των μαθηματικών μοντέλων του αφυγραντήκαι του αναγεννητή. Τα μοντέλα αφορούν τρεις διαφορετικές διατάξεις: την αδιαβατικήσυσκευή με το πληρωτικό υλικό, τη μη αδιαβατική συσκευή με το σωληνοειδή εναλλάκτη καιτη μη αδιαβατική συσκευή με τον πλακοειδή εναλλάκτη. Όλα τα μοντέλα συγκρίνονται μεπειραματικά δεδομένα από την ήδη υπάρχουσα βιβλιογραφία και δείχνουν αξιόπιστησυμπεριφορά, παρουσιάζοντας μικρές αποκλίσεις μεταξύ τους. Η εκτενής παραμετρικήανάλυση που διεξάγεται σε κάθε επικυρωμένο μαθηματικό μοντέλο υποδεικνύει τουςσημαντικότερους παράγοντες που επηρεάζουν την ενεργειακή απόδοση του αφυγραντή καιτου αναγεννητή. Η πειραματική διαδικασία που διεξάγεται στα πλαίσια της εργασίας αυτήςπροσφέρει πολύτιμες γνώσεις για τη λειτουργία αυτών των κλιματιστικών συσκευών. Ταπειραματικά αποτελέσματα δείχνουν ότι ο ρυθμός αφύγρανσης του αέρα κυμαίνεται από 6.99έως 11.90 kg νερού/ώρα και η ενεργειακή κατανάλωση του αναγεννητή κυμαίνεται από 6.93kWh έως 26.22 kWh, ανάλογα με τις εκάστοτε συνθήκες λειτουργίας. Ικανοποιητική απόδοσητου αναγεννητή επιτυγχάνεται ακόμη και με θερμοκρασία θερμού νερού 46.11 oC. Η χαμηλήθερμοκρασία που απαιτείται για τη λειτουργία αυτών των κλιματιστικών μονάδων ευνοεί τηχρήση ανανεώσιμων πηγών ενέργειας, αποκτώντας έτσι περιβαλλοντικά και οικονομικάπλεονεκτήματα έναντι των συμβατικών κλιματιστικών συστημάτων συμπίεσης ατμού.

Study question Can oocytes isolated from transgender men after oophorectomy support embryonic development? Summary answer Embryo developmental arrest at 4–8cell stage (day 3 embryos) indicates poor quality of in vitro matured oocytes from transgender men. What is known already Gender affirming surgery for transgender men leads to permanent infertility, as it involves bilateral oophorectomy. Current approaches for fertility preservation, such as oocyte freezing following ovarian hyperstimulation, may interfere with the wanted masculine characteristics and enhance gender dysphoria. In vitro matured oocytes (IVM) isolated following oophorectomy have been proposed as a source of potential gametes to ensure fertility preservation for transgender men with a child wish. From previous studies, it has been shown that these oocytes are able to undergo maturation and display normal spindles, but their competence to be fertilized and support embryonic development has not been addressed yet. Study design, size, duration We evaluated the quality of in vitro matured oocytes isolated from ovaries of transgender men by applying calcium imaging and monitoring fertilization and embryonic development following intracytoplasmic sperm injection (ICSI). Ovaries were collected in cold (4oC) or warm (37oC) medium, to investigate the best collection procedure. So far, results from four transgender men have been included. Participants/materials, setting, methods: Ovaries from four transgender men undergoing testosterone treatment were collected after oophorectomy in cold or warm medium. Cumulus oocyte complexes (COCs) were isolated and cultured in maturation medium for 48hrs. Mature oocytes were injected with donated sperm and assessed either by calcium imaging, measuring the total calcium release following injection, or following embryonic development. Donated in vitro matured oocytes, germinal vesicle(GV) or metaphase I(MI) origin, from other patients undergoing IVF treatment were used as controls. Main results and the role of chance In total, 179 COCs were collected from ovaries (n = 8) of four transgender men. From the COCs collected in warm medium, 73/105(69%) survived and 33/73(45%) reached metaphase II (MII). Of 21 MII injected with sperm, 13/21(62%) fertilized, 9/21(43%) formed 2 pronuclei (PN), 8/9(89%) reached the 2-cell stage, 3/9(33%) reached 4–8cell stage but arrested. From 74 COCs isolated in cold medium, 57/74(77%) survived and 28/57(49%) matured. Of the 11 MII injected with sperm, 7/11(64%) fertilized, 6/11(54%) formed 2PN, 6/6(100%) reached the 2-cell stage, 4/6(67%) reached 4–8cell but arrested. In the control group, 10/13 oocytes injected with the same sperm sample, were normally fertilized (77%), 8/10(80%) reached the 2-cell stage, 7/10(70%) reached the 4–8cell stage and 4/10(40%) became blastocysts. From the warm, cold and control conditions, respectively 12,14 and 17 MII oocytes were used for calcium imaging. The product of amplitude and frequency of calcium peaks, representing total calcium release, was calculated. Oocytes showed an average release of 0.66AU and 1.69AU for the warm and cold condition, respectively. The average value for control oocytes was 2.19AU. Limitations, reasons for caution One major limitation of our study is the lack of ovaries from cis women as control group. Our control oocytes originated from women undergoing IVF treatment and have undergone ovarian stimulation. Furthermore, the number of oocytes analysed and number of patients per group was limited and is being increased. Wider implications of the findings: Our data indicate that in vitro matured oocytes from transgender men ovaries display poor quality, as demonstrated by the poor embryonic development. In the future, we will apply nuclear transfer technology as a mean to overcome embryonic developmental arrest in this group of oocytes. Trial registration number Not applicable

Fetuses that have not achieved their full growth potential are associated with adverse perinatal and long-term outcomes; thus, it is essential to identify environmental factors that can potentially impair normal intrauterine development. Endocrine disrupting compounds (EDCs), substances capable of altering the homeostasis of the endocrine system, are thought to play a role in restriction of growth velocity, with phthalates being among the most common EDCs to which pregnant women are exposed. Such exposure can potentially lead to changes to the epigenome, placental structure, and hormone function and trigger oxidative stress. Given that these pathways have been linked to fetal growth restriction, we reviewed the literature on the relationship between phthalates and fetal growth. The majority of the studies, which used birth weight as an indicator of intrauterine development, showed contradictory results, the main reason being the EDCs' rapid metabolism. However, we can draw more consistent conclusions when phthalates are quantified at more than one time point during pregnancy. In this narrative review, we present current data indicating the role of phthalates, and especially di-(2-ethylhexyl) phthalate (DEHP), in abnormal fetal growth velocity.

The historical and future impacts of atmospheric deposition of inorganic nitrogen (N) and phosphorus (P) on the marine ecosystem in the east Mediterranean Sea are investigated by using a 1D coupled physical– biogeochemical model, set up for the Cretan Sea as a representative area of the basin. For the present-day simulation (2010), the model is forced by observations of atmospheric deposition fluxes at Crete, while for the hindcast (1860) and forecast (2030) simulations, the changes in atmospheric deposition calculated by global chemistry–transport models are applied to the present-day observed fluxes. The impact of the atmospheric deposition on the fluxes of carbon in the food chain is calculated together with the contribution of human activities to these impacts. The results show that total phytoplanktonic biomass increased by 16% over the past 1.5 centuries. Small fractional changes in carbon fluxes and planktonic biomasses are predicted for the near future. Simulations show that atmospheric deposition of N and P may be the main mechanism responsible for the anomalous N:P ratio observed in the Mediterranean Sea.

Atmospheric deposition of nitrogen and phosphorus represents an important source of nutrients, enhancing the marine productivity in oligotrophic areas, e.g., the Mediterranean. A comprehensive biogeochemical model (ERSEM) was setup and customized to simulate a mesocosm experiment, where dissolved inorganic nitrogen and phosphorus by means of atmospheric dust (single addition/SA and repetitive addition/RA in three successive doses) was added in controlled tanks and compared with a control (blank), all with Cretan Sea (Eastern Mediterranean) water. Observations on almost all components of the pelagic ecosystem in a ten-day period allowed investigating the effect of atmospheric deposition and the pathways of the added nutrients. The model was able to reasonably capture the observed variability of different ecosystem components and reproduce the main features of the experiment. An enhancement of primary production and phytoplankton biomass with added nutrients was simulated, in agreement with observations. A significant increase of bacterial production was also reproduced, while the model underestimated the observed increase and variability in bacterial biomass, but this deviation could be partly removed considering a lower carbon conversion factor from cell abundance data. A slightly stronger overall response was simulated with the single dust addition, compared to the repetitive that showed a few days delay. The simulated carbon pathways indicated that nutrient additions did not modify the microbial food web structure, but just increased its trophic status. Changes in model assumptions and parameter set that were necessary to reproduce the observed variability in the mesocosm experiment were discussed through a series of sensitivity simulations. Bacterial production was assumed to be mostly affected by the in situ produced labile organic matter, while it was further stimulated by the addition of inorganic nutrients, adopting a function of external nutrient concentrations for bacteria nutrient limitation. The effective increase in phytoplankton nutrient uptake rate was necessary, in order to reproduce the observed primary production, under such low nutrient concentrations, as also the increase of the grazers growth rate. The model was thus tuned to better work under very low nutrient concentrations, such as those found in the Eastern Mediterranean.

The effect of episodicity of Saharan dust deposition on the pelagic microbial food web was studied in the oligotrophic Eastern Mediterranean by means of a mesocosm experiment in May 2014. Two different treatments in triplicates (addition of natural Saharan dust in a single-strong pulse or in three smaller consecutive doses of the same total quantity), and three unamended controls were employed; chemical and biological parameters were measured during a 10-day experiment. Temporal changes in primary (PP) and bacterial (BP) production, chlorophyll a (Chl a) concentration and heterotrophic bacteria, Synechococcus and mesozooplankton abundance were studied. The results suggested that the auto- and hetero-trophic components of the food web (at least the prokaryotes) were enhanced by the dust addition (and by the nitrogen and phosphorus added through dust). Furthermore, a 1-day delay was observed for PP, BP, and Chl a increases when dust was added in three daily doses; however, the maximal values attained were similar in the two treatments. Although, the effect was evident in the first osmotrophic level (phytoplankton and bacteria), it was lost further up the food web, masked under the impact of grazing exerted by predators such as heterotrophic flagellates, ciliates and dinoflagellates. This was partly proved by two dilution experiments. This study demonstrates the important role of atmospheric deposition and protist grazing when evaluating the effect on oligotrophic systems characterized by increased numbers of trophic levels.

To investigate hypoxia-inducible factor-1α (HIF-1α) expression in placentae of women with iron-deficiency anemia and β-thalassemia trait and to correlate the results with hematological parameters as well as with parameters associated with the outcome of pregnancy.About 126 women who delivered in the Larissa University Hospital were divided in three groups: iron-deficiency anemia (n = 39), β-thalassemia trait carriers (n = 53) and control group (n = 34). HIF-1α expression was assessed with immunochemical assays and statistical analysis was performed with chi-squared test and ANOVA.HIF-1α immunostaining was intense in the two groups of anemia. A statistically significant association was found between HIF-1α immunoreactivity and hematocrit (p 0.001), hemoglobin (p 0.001), MCV (p 0.001), transferrin (p 0.001) and its receptors (p = 0.040), whereas no significant correlations were observed between HIF-1α, iron serum levels (p = 0.256) and ferritin (p = 0.232). We found no association between HIF-1α and birthweight (p = 0.256), placental weight (p = 0.870) and Apgar score at 1' (p = 0.210) and 5' (p = 0.400).HIF-1α expression is affected by anemia, although this factor has no important direct effect on the perinatal outcome.

Atmospheric deposition provides significant amounts of nutrients to the continental and marine ecosystems. Using the mesoscale WRF/CMAQ modeling system, the nitrogen (N) and sulfur (S) atmospheric deposition fluxes over the Mediterranean and the Black seas and continental Europe are evaluated for the year 2008. The annual N and S deposition fluxes are calculated to be 4.89 Tg(N) yr −1 and 2.07 Tg(S) yr −1 over continental Europe, 0.92 Tg(N) yr −1 and 0.52 Tg(S) yr −1 over West Mediterranean, 1.10 Tg(N) yr −1 and 0.84 Tg(S) yr −1 over East Mediterranean and 0.36 Tg(N) yr −1 and 0.17 Tg(S) yr −1 over the Black Sea. Inorganic N deposition fluxes are calculated to be about 3 times higher than gaseous organic N deposition fluxes. Comparison to available observations associates the annual mean model estimates with about 40 ± 30% of uncertainty depending on location. Dry deposition dominates over wet deposition for both N and S in agreement with the observations. Results suggest that an important fraction of the N deposited over the Mediterranean basin can be attributed to transported N species while S deposition is dependent more on the local emissions. In Black Sea and West Mediterranean Sea waters the calculated atmospheric N inputs are comparable to the N export measured by sediment traps whereas in the East Mediterranean N input exceeds by a factor of about 5 the N export. Our simulations show that the critical N load of 1 g(N) m −2 yr −1 is exceeded over 84% of the European forested areas.

This study investigates the impact of atmospheric deposition on the marine ecosystem of the East Mediterranean Sea. Atmospheric deposition has been suggested to be more important than land inputs of nutrients to the East Mediterranean Sea. For the first time, atmospheric deposition measurements of dissolved inorganic phosphorous and nitrogen over Crete are used together with marine ecosystem observations in the Cretan Sea and a one-dimension physical/biogeochemical marine model. The adopted model configuration successfully reproduces observations of production rates and biomasses of phytoplankton and bacteria in the region. The atmospheric deposition of N and P to the East Mediterranean is shown to increase the primary production by 1–35% depending on season with the maximum impact calculated for summer and fall. Biomasses subsequently increase by 2–26% for phytoplankton and up to 7% for bacteria. The total organic carbon integrated year-around in the first 200 m of the water column increases by about 30%. The results also show the importance of the rate of P preferential to N remineralization in the upper sea water layer for the marine productivity. Simulations indicate that continuous atmospheric inputs of nutrients over several decades can maintain the anomalously high N-to-P ratio observed in the East Mediterranean seawater.

Liquid desiccant air conditioning systems have recently been attracting attention due to their capability of handling the latent load without super-cooling and then reheating, as happens in the conventional compression-type air conditioning systems. In liquid desiccant cooling cycles, a sorbent solution is employed to dehumidify the air, circulating between the two critical components; the dehumidifier and the regenerator. As the strong desiccant solution is sprayed on top of the internally cooled dehumidifier, it flows down by gravity and comes in contact with the process air. The desiccant solution which, by definition, has a strong affinity for water vapor absorbs moisture from the air. The end of the process finds the air cool and dehumidified and the solution diluted. The diluted desiccant solution enters the regenerator in order to retrieve its initial concentration. Hot water derived from a low temperature source supplies the necessary heat to the solution and the excessive water content is evaporated. At the end of the process, the hot humid air is rejected to the ambient and the concentrated solution is driven to the dehumidifier. The complex heat and mass transfer phenomena, occurring both in the dehumidifier and regenerator, has been the subject of earlier work by the authors. Based on the knowledge gained, a liquid desiccant system was installed at the National Technical University of Athens, Laboratory of Applied Thermodynamics, for experimental purposes. The liquid desiccant system was constructed by the German company L-DCS [1]. The main components of the system are the dehumidifier, the regenerator and the evaporative cooler. The system uses water as the cooling medium and LiCl solution as the desiccant. It also employs two storage tanks, one for the concentrated solution and one for the diluted. The purpose of this publication is to present the newly installed liquid desiccant system, to predict the performance of the dehumidifier and to carry out preliminary design optimization.

Liquid desiccant air conditioning systems have recently been attracting attention, owing to their merits in handling the latent heat. Desiccant systems avoid not only the energy penalty caused by overcooling and reheating, but also the bacteria generation caused by condensed water. They can also significantly reduce the electricity peak load caused by conventional compression type air conditioning systems, especially in hot and humid regions. Desiccant systems are thus more energy efficient, healthy and environmentally friendly than conventional mechanical cooling. This paper presents the results from a theoretical study of a liquid desiccant system that provides air conditioning to a typical office building. A coupled heat and mass transfer analytical model was developed, based on the Runge-Kutta fixed step method, to predict the performance of the device under Mediterranean conditions. A parametric analysis was implemented to investigate the effects of ambient temperature and humidity ratio on the dehumidification mass rate, the load coverage and the thermal COP of the system. Simulation results showed that under hot and humid weather, the COP reaches its maximum value, 1.075. However, as the weather becomes more humid, the latent load coverage of the system is decreased and as it becomes hotter, the sensible load coverage of the system is decreased. The maximum latent load coverage, 91.8%, happened at 40°C, 0.011kgw/kgdα. Results can be useful for researchers and engineers.Copyright © 2012 by ASME

Liquid desiccant systems are emerging as promising alternatives to achieve humidity control in a variety of applications with high latent loads and low humidity requirements. Their advantage lies on their ability to handle the latent load without super-cooling and then reheating the air, as happens in a conventional compression-type air conditioning system. This paper presents the results from a study of the performance of a counter flow internally heated liquid desiccant regenerator. A tubular heat exchanger is proposed as the internally heated element of the regenerator and water as the heating fluid. The desiccant solution is sprayed into the internally heated regenerator from the top and flows down by gravity. At the same time, ambient air is blown from the bottom, counter-flowing with the desiccant solution. The desiccant is in direct contact with the air, allowing for heat and mass transfer. The water, flowing inside the tubes of the regenerator, provides the necessary heat for regeneration. A heat and mass transfer theoretical model has been developed, based on the RungeKutta fixed step method, to predict the performance of the device under various operating conditions. Experimental data from previous literature have been used to validate the model. Excellent agreement has been found between experimental tests and the theoretical model, with the deviation not exceeding ±6.1%. Following the validation of the mathematical model, the dominating effects on the desorption process have been discussed in detail. The three most commonly used liquid desiccant solutions (LiCl, LiBr, CaCl2) and two different flows (DDU: water downward – desiccant downward – air upward, UDU: water upward – desiccant downward – air upward) have been also evaluated against each other. Considering the flow analysis, the type of flow does not affect the regeneration capacity as much as the type of the desiccant solution. It has been concluded that high regeneration rate can be achieved under DDU flow (water downward – desiccant downward – air upward), low solution concentration, high air inlet temperature, high solution inlet temperature, low air inlet humidity ratio and CaCl2 as the desiccant solution.

Liquid desiccant air conditioning systems have recently been attracting attention due to their capability of handling the latent load without super-cooling and then reheating the air, as happens in a conventional compression-type air conditioning system. This paper presents the results from a study of the performance of an internally cooled liquid desiccant dehumidifier. A plate heat exchanger is proposed as the internally cooled element of the dehumidifier and water as the cooling fluid. The desiccant solution is sprayed into the internally cooled dehumidifier from the top and flows down by gravity. At the same time, fresh humid air is blown from the bottom or top, counter-flowing or co-flowing with the desiccant solution. The desiccant is in direct contact with the air, allowing for heat and mass transfer. The cooling water, flowing inside the plates of the dehumidifier, carries out the heat of the crossed air and solution. A heat and mass transfer theoretical model has been developed, based on the Runge-Kutta fixed step method, to predict the performance of the device under various operating conditions. Experimental data from previous literature have been used to validate the model. Excellent agreement has been found between experimental tests and the theoretical model, with the deviation not exceeding ±4.1% for outlet air temperature and ±4.0% for outlet humidity ratio. Following the validation of the mathematical model, the dominating effects on the absorption process have been discussed in detail. Namely, effects of flow configuration, air inlet temperature, humidity and flow rate, as well as desiccant inlet temperature, concentration and flow rate have been investigated against the dehumidification rate and the cooling efficiency. The two most commonly used liquid desiccant solutions, namely LiCl and LiBr have been also evaluated against each other. The results suggested that high dehumidification mass rate can be achieved under counter flow between air and solution, low air mass flow rates, low cooling water temperature, low desiccant temperature and LiCl as the desiccant solution.Copyright © 2012 by ASME

Hybrid Liquid Desiccant Cooling / Vapour Compression Systems is an environmentally friendly technology used to condition the internal environment of buildings. In contrast to conventional vapor compression air conditioning systems, in which the electrical energy drives the cooling cycle, desiccant cooling is heat driven; therefore, hybrid LDC/VCS have the potential to utilise cleaner energy sources such as gas, hot water, waste heat or solar thermal energy. In hybrid LDC/VCS, the latent cooling load is handled by the desiccant dehumidifier, while the sensible is handled by a conventional VCS. Hybrid systems combining liquid desiccant cooling with Vapor Compression Systems, Vapor Absorption Systems and Solar Collectors use less electrical energy compared to conventional air-conditioning alone, while these savings rise as the latent load increases. Unlike other surveys on desiccant cooling, this review focuses on a detailed coverage of the hybrid LDC/VC systems. Commonly used liquid desiccants are compared towards their physical properties. Hybrid LDC/VCS employing various components and features are summarized, while different system configurations are schematically presented. Key factors for the hybrid system performance are the desiccant material, the design variables and the conduction of experiments prior to operation.Copyright © 2008 by ASME

The Nernst and Hall effects in single crystals of very pure gallium were measured at 4.2 and 1.71K in magnetic fields up to about 40 kG. The Nernst effect shows oscillations when the magnetic field lies along, or very near, the c axis and the temperature gradient Del T is parallel to the b axis, while the Hall effect does not exhibit any oscillation in the same orientations.