Oocyte meiotic-stage-specific differences in spindle depolymerization in response to temperature changes monitored with polarized field microscopy and immunocytochemistry

Objective: To compare the polymerization status of mouse oocyte spindles exposed to various temperatures at various stages of meiosis. Design: Experimental animal study. Setting: University animal laboratory. Animal(s): CF1 mice. Intervention(s): Immature oocytes matured to metaphase I (MI), telophase I (TI), and metaphase II (MII) were incubated at 37 degrees C (control), room temperature (RT), or 4 degrees C for 0, 10, 30, and 60 minutes. Spindle analysis subsequently was performed using polarized field microscopy and immunocytochemistry. Spindles of TI and MII oocytes that underwent vitrification and warming were analyzed also by immunocytochemistry. Main Outcome Measure(s): Detection of polymerized meiotic spindles. Result(s): At RT, and after 60 minutes at 4 degrees C, a significant time-dependent decrease in the percentage of polymerized meiotic spindles was observed in MI and MII oocytes, but not in TI oocytes. The polymerization of TI spindles at 4 degrees C was similar to that of TI spindles at 4 degrees C that underwent vitrification and warming. Conclusion(s): Significant differences in the microtubule dynamics of MI, TI, and MII oocytes incubated at different temperatures were observed. In particular, meiotic spindles in TI oocytes exhibited less depolymerization than did metaphase spindles. (Fertil Steril (R) 2012; 97: 714-9. (C) 2012 by American Society for Reproductive Medicine.)

The Influence of Environmental Temperature and Air Humidity on the Maintenance of Sterility of Surgical Instruments Sterilized in Different Wraps

State of Sao Paulo Research Foundation (FAPESP), Brazil

Can postural control performance be an indicator of truck drivers' sleep deprivation?

Long-haul drivers work in irregular schedules due to load delivery demands. In general, driving and sleeping occur at irregular times and, consequently, partial sleep deprivation and/or circadian misalignment may emerge and result in sleepiness at the wheel. In this way, the aim of this study was to verify changes in the postural control parameters of professional drivers after one-night working. Eight male truck drivers working at night - night drivers (ND) and nine day drivers (DD) volunteered to participate in this study. The night drivers' postural stability was assessed immediately before and after an approximately 430 km journey by two identical force platforms at departure and arrival sites. The DD group was measured before and after a day's work. An interaction effect of time of day and type of shift in both conditions: eyes open (p < 0.01) and eyes closed (p < 0.001) for amplitude of mediolateral movements was observed. Postural stability, measured by force platform, is affected by a night of work, suggesting that it could be an effect of circadian and homeostatic influences over postural control.

The migration of Mn2+ ions in Cd1-xMnxS nanocrystals: Thermal annealing control

This work reports evidence of the induced migration of Mn2+ ions in Cd(1-x)MnxS nanocrystals (NCs) by selecting a specific thermal treatment for each sample. The growth and characterization of these magnetic dots were investigated by atomic force microscopy (AFM), optical absorption (OA), and electronic paramagnetic resonance (EPR) techniques. The comparison of experimental and simulated EPR spectra confirms the incorporation of Mn2+ ions both in the core and at the dot surface regions. The thermal treatment of a magnetic sample, via selected annealing temperature and/or time, affects the fine and hyperfine interaction constants which modify the shape and the intensity of the EPR transition spectrum. The identification of these changes has allowed tracing the magnetic ion migration from core to surface regions of a dot as well as inferring the local density of the magnetic impurity ions. (C) 2011 Elsevier Ltd. All rights reserved.

Biological Characteristics and Thermal Requirements of the Biological Control Agent Telenomus remus (Hymenoptera: Platygastridae) Reared on Eggs of Different Species of the Genus Spodoptera (Lepidoptera: Noctuidae)

The biological characteristics of Telenomus remus Nixon, 1937 (Hymenoptera: Platygastridae) on eggs of Spodoptera albula (Walker, 1857); S. cosmioides Walker 1858, S. eridania (Cramer, 1782); and S. frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) were evaluated under different temperatures (19, 22, 25, 28, 31, and 34 degrees C +/- 1 degrees C). The duration of the T remus egg-to-adult period on eggs of all four Spodoptera species and the longevity of adults of T. remus were both inversely proportional to the increase in temperature. Parasitoid emergence was higher than 80% at temperatures from 19 to 28 degrees C when the parasitoid was reared on eggs of S. eridania and S. frugiperda. Differently, when the parasitoid was reared on eggs of S. albula and S. cosmioides, T. remus emergence at rates of 80% or higher just occurred from 22 to 25 degrees C and at 22 degrees C, respectively. At 34 degrees C, this parameter was lower than 30% for T reams reared in all hosts. The sex ratio was 64-86% females, except for T. remus in S. cosmioides eggs at 34 C, in which temperature it was 39%. The estimated thermal requirements of T. remus, for the thermal constant (K) and the base temperature (T(base)), were: 125.39 DD and 15.139 degrees C; 125.56 DD and 14.912 degrees C; 142.98 DD and 14.197 degrees C; and 149.16 DD and 13.846 degrees C, for S. cosmioides, S. frugiperda, S. albula, and S. eridania, respectively. In general, T. remus showed good parasitism potential on all the hosts, although eggs of S. frugiperda, S. eridania, and S. albula proved to be the most suitable for mass rearing of T reams in the laboratory. Eggs of S. cosmioides are less suitable because of the lower parasitoid emergence observed at most of the temperatures with exception of 22 degrees C.

Effects of light intensity and temperature on Cylindrospermopsis raciborskii (Cyanobacteria) with straight and coiled trichomes: growth rate and morphology

Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju (Ordem Nostocales) is one of the most troublesome bloom-forming species in Brazil. Understanding the population dynamics of the different morphotypes of C. raciborskii (straight and coiled) could assist in the prediction of favourable conditions for the proliferation of this potentially toxin-producing species. The aim of the present study was to assess the effects of two different light intensities and temperatures on the growth rate and morphology of the trichomes of the straight and coiled morphotypes. For such, two non-toxin producing strains of C. raciborskii were used - one with a coiled trichome (ITEP31) and another with a straight trichome (ITEP28). The strains were cultured in BG-11 medium in a climatic chamber under controlled conditions. Two light intensities (30 and 90 mu mol.m(-2).s(-1)) were combined at temperatures of 21 and 31 degrees C and the growth rate and morphological changes were analysed. The morphotypes responded differently to the different temperatures and light intensities. Both strains exhibited faster growth velocities when submitted to higher light intensity and temperature. The lower temperature and higher luminosity hampered the development of both strains. Variations in cellular morphology and an absence of akinetes in both strains were related to the lower temperature (21 C). The coiled morphotype demonstrated considerable phenotype plasticity, changing the morphology of trichome throughout its growth curve. Although molecular analysis does not sustain the separation of the morphotypes as distinct species, their different eco-physiological responses should be considered further knowledge of extreme importance for the population control of these potentially toxic organisms.

An electrochemical gas sensor based on paper supported room temperature ionic liquids

A sensitive and fast-responding membrane-free amperometric gas sensor is described, consisting of a small filter paper foil soaked with a room temperature ionic liquid (RTIL), upon which three electrodes are screen printed with carbon ink, using a suitable mask. It takes advantage of the high electrical conductivity and negligible vapour pressure of RTILs as well as their easy immobilization into a porous and inexpensive supporting material such as paper. Moreover, thanks to a careful control of the preparation procedure, a very close contact between the RTIL and electrode material can be achieved so as to allow gaseous analytes to undergo charge transfer just as soon as they reach the three-phase sites where the electrode material, paper supported RTIL and gas phase meet. Thus, the adverse effect on recorded currents of slow steps such as analyte diffusion and dissolution in a solvent is avoided. To evaluate the performance of this device, it was used as a wall-jet amperometric detector for flow injection analysis of 1-butanethiol vapours, adopted as the model gaseous analyte, present in headspace samples in equilibrium with aqueous solutions at controlled concentrations. With this purpose, the RTIL soaked paper electrochemical detector (RTIL-PED) was assembled by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide as the wicking RTIL and printing the working electrode with carbon ink doped with cobalt(II) phthalocyanine, to profit from its ability to electrocatalyze thiol oxidation. The results obtained were quite satisfactory (detection limit: 0.5 mu M; dynamic range: 2-200 mu M, both referring to solution concentrations; correlation coefficient: 0.998; repeatability: +/- 7% RSD; long-term stability: 9%), thus suggesting the possible use of this device for manifold applications.

Endophytic fungi from Vitis labrusca L. ('Niagara Rosada') and its potential for the biological control of Fusarium oxysporum

We investigated the diversity of endophytic fungi found on grape (Vitis labrusca cv. Niagara Rosada) leaves collected from Salesopolis, SP, Brazil. The fungi were isolated and characterized by amplified ribosomal DNA restriction analysis, followed by sequencing of the ITS1-5.8S-ITS2 rDNA. In addition, the ability of these endophytic fungi to inhibit the grapevine pathogen Fusarium oxysporum f. sp herbemontis was determined in vitro. We also observed that the climatic factors, such as temperature and rainfall, have no effect on the frequency of infection by endophytic fungi. The endophytic fungal community that was identified included Aporospora terricola, Aureobasidium pullulans, Bjerkandera adusta, Colletotrichum boninense, C. gloeosporioides, Diaporthe helianthi, D. phaseolorum, Epicoccum nigrum, Flavodon flavus, Fusarium subglutinans, F. sacchari, Guignardia mangiferae, Lenzites elegans, Paraphaeosphaeria pilleata, Phanerochaete sordida, Phyllosticta sp, Pleurotus nebrodensis, Preussia africana, Tinctoporellus epiniltinus, and Xylaria berteri. Among these isolates, two, C. gloeosporioides and F. flavus, showed potential antagonistic activity against F. oxysporum f. sp herbemontis. We suggest the involvement of the fungal endophyte community of V. labrusca in protecting the host plant against pathogenic Fusarium species. Possibly, some endophytic isolates could be selected for the development of biological control agents for grape fungal disease; alternatively, management strategies could be tailored to increase these beneficial fungi.

The impact of rising sea temperature on innate immune parameters in the tropical subtidal sea urchin Lytechinus variegatus and the intertidal sea urchin Echinometra lucunter

Ocean temperatures are rising throughout the world, making it necessary to evaluate the impact of these temperature changes on sea urchins, which are well-known bioindicators. This study evaluated the effect of an increase in temperature on the immune response of the subtidal Lytechinus variegatus and the intertidal Echinometra lucunter sea urchins. Both species were exposed to 20 (control), 25 and 30 °C temperatures for 24 h, 2, 7 and 14 days. Counting of coelomocytes and assays on the phagocytic response, adhesion and spreading of coelomocytes were performed. Red and colorless sphere cells were considered biomarkers for heat stress. Moreover, a significant decrease in the phagocytic indices and a decrease in both cell adhesion and cell spreading were observed at 25 and 30 °C for L. variegatus. For E. lucunter, the only alteration observed was for the cell proportions. This report shows how different species of sea urchins respond immunologically to rising temperatures

On the respiratory metabolism of marine plankton: its application in assessing carbon fluxes and the role of substrates in its biochemical control

Programa de doctorado en Oceanografía. La fecha de publicación es la fecha de lectura

Characterisation of probiotic strains for the control and prevention of enteropathogens in the food chain

60 strains (belonging to the genera Lactobacillus, Bifidobacterium, Leuconostoc and Enterococcus) were tested for their capacity to inhibit the growth of 3 strains of Campylobacter jejuni: Lactobacilli and bifidobacteria were left to grow in MRS or TPY broth at 37°C overnight in anaerobic conditions; Campylobacter jejuni was inoculated in blood agar plates at 37°C for 24-48 hours in microaerophilic conditions. The inhibition experiments were carried out in vitro using ”Spot agar test” and “Well diffusion assay” techniques testing both cellular activity and that of the surnatant. 11 strains proved to inhibit the growth of Campylobacter jejuni. These strains were subsequently analised analised in order to evaluate the resistance to particular situations of stress which are found in the gastrointestinal tract and during the industrial transformation processes (Starvation stress, osmotic stress, heat stress, resistance to pH and to bile salts). Resistance to starvation stress: all strains seemed to resist the stress (except one strain). Resistance to osmotic stress: all strains were relatively resistant to the concentrations of 6% w/v of NaCl (except one strain). Resistance to heat stress: only one strain showed little resistance to the 55°C temperature. Resistance to pH: In the presence of a low pH (2.5), many strains rapidly lost their viability after approximately 1 hour. Resistance to bile salts: Except for one strain, all strains seemed to be relatively resistant to the 2% w/v concentration of bile salts. Afterward, strains were identified by using phenotipic and molecular techniques. Phenotipic identification was carried out by using API 50 CHL (bioMérieux) and API 20 STREP identification system (bioMérieux); molecular identification with species-specific PCR: the molecular techniques confirmed the results by phenotipic identification. For testing the antibiotic resistance profile, bacterial strains were subcultured in MRS or TPY broth and incubated for 18 h at 37°C under anaerobic conditions. Antibiotics tested (Tetracycline, Trimethoprim, Cefuroxime, Kanamycin, Chloramphenicol, Vancomycin, Ampycillin, Sterptomycin, Erythromycin) were diluted to the final concentrations of: 2,4,8,16,32,64,128,256 mg/ml. Then, 20 μl fresh bacterial culture (final concentration in the plates approximately 106 cfu/ml) were added to 160 μl MRS or TPY broth and 20 μl antibiotic solution. As positive control the bacterial culture (20 ul) was added to broth (160 ul) and water (20 ul). Test was performed on plates P96, that after the inoculum were incubated for 24 h at 37oC, then the antibiotic resistance was determined by measuring the Optical Density (OD) at 620 nm with Multiscan EX. All strains showed a similar behaviour: resistance to all antibiotic tested. Further studies are needed.

Diffusivity and enzymatic activity control the exchange of carbonyl sulfide (COS) between soils and the atmosphere

Carbonylsulfid (COS) ist eines der stabilsten reduzierten schwefelhaltigen Spurengase in der Atmosphäre. In der gut durchmischten Troposphäre bewegt sich seine Konzentration um 500 ppt. COS spielt eine wichtige Rolle in der Produktion von stratosphärischem Aerosol und im Ozon Zyklus. Dieses Spurengas hat eine Vielfalt an natürlichen und anthropogenen Quellen, denen gleichstarke Senken, darunter die dominanten wie Vegetation und Boden, gegenüber stehen. Die Stärke der Senken ist trotz langjähriger Forschungen immer noch Gegenstand der Diskussionen. Daher ist es wichtig die kontrollierenden Parameter zu charakterisieren. Alle Austauschmessungen vor 1990 vermuteten Böden als Quelle von COS, was aber durch Castro and Galloway (1991) klar widerlegt wurde. Heute werden Böden in Ergänzung zur Vegetation grundsätzlich als Senke betrachtet. Vor diesem Hintergrund wurden Bodenproben auf den Austausch von Carbonylsulfid mit der Atmosphäre unter verschiedenen Umgebungsbedingungen untersucht. Drei Ackerböden aus Deutschland, China und Finnland und zwei Waldböden aus Sibirien und Surinam konnten parametrisiert werden in Relation zur atmosphärischen Umgebungskonzentration, Temperatur und Bodenfeuchte (WC). Neben Umgebungskonzentration und Bodenfeuchte, scheinen Bodenstruktur und enzymatische Aktivität die Richtung und Größe des Austauschflusses zu kontrollieren. Die übereinstimmenden Optima für boreale Böden in Relation zum wassergefüllten Porenvolumen des Bodens (WFPS) und die Linearität zwischen Depositionsgeschwindigkeit (Vd) und Bulk density lassen auf eine Dominanz der Abhängigkeit der COS-Aufnahme von der durch WFPS bestimmten Diffusionsfähigkeit schließen. WFPS ist abhängig von WC, Bodenstruktur und Bodenporosität. In Ergänzung zu diesen eher physikalischen Parametern konnte die Carboanhydrase (CA) als kontrollierendes Enzym in Böden identifiziert werden. Erste Versuche zur direkten Bestimmung der CA in den untersuchten Böden erlaubten eine erste, aber noch sehr ungenaue Abschätzung der Enzymaktivität.

Model predictive control in thermal management of multiprocessor systems-on-chip

MultiProcessor Systems-on-Chip (MPSoC) are the core of nowadays and next generation computing platforms. Their relevance in the global market continuously increase, occupying an important role both in everydaylife products (e.g. smartphones, tablets, laptops, cars) and in strategical market sectors as aviation, defense, robotics, medicine. Despite of the incredible performance improvements in the recent years processors manufacturers have had to deal with issues, commonly called “Walls”, that have hindered the processors development. After the famous “Power Wall”, that limited the maximum frequency of a single core and marked the birth of the modern multiprocessors system-on-chip, the “Thermal Wall” and the “Utilization Wall” are the actual key limiter for performance improvements. The former concerns the damaging effects of the high temperature on the chip caused by the large power densities dissipation, whereas the second refers to the impossibility of fully exploiting the computing power of the processor due to the limitations on power and temperature budgets. In this thesis we faced these challenges by developing efficient and reliable solutions able to maximize performance while limiting the maximum temperature below a fixed critical threshold and saving energy. This has been possible by exploiting the Model Predictive Controller (MPC) paradigm that solves an optimization problem subject to constraints in order to find the optimal control decisions for the future interval. A fully-distributedMPC-based thermal controller with a far lower complexity respect to a centralized one has been developed. The control feasibility and interesting properties for the simplification of the control design has been proved by studying a partial differential equation thermal model. Finally, the controller has been efficiently included in more complex control schemes able to minimize energy consumption and deal with mixed-criticalities tasks

Chiral properties of two-flavour QCD at zero and non-zero temperature

Lattice Quantum Chromodynamics (LQCD) is the preferred tool for obtaining non-perturbative results from QCD in the low-energy regime. It has by nowrnentered the era in which high precision calculations for a number of phenomenologically relevant observables at the physical point, with dynamical quark degrees of freedom and controlled systematics, become feasible. Despite these successes there are still quantities where control of systematic effects is insufficient. The subject of this thesis is the exploration of the potential of todays state-of-the-art simulation algorithms for non-perturbativelyrn$\mathcal{O}(a)$-improved Wilson fermions to produce reliable results in thernchiral regime and at the physical point both for zero and non-zero temperature. Important in this context is the control over the chiral extrapolation. Thisrnthesis is concerned with two particular topics, namely the computation of hadronic form factors at zero temperature, and the properties of the phaserntransition in the chiral limit of two-flavour QCD.rnrnThe electromagnetic iso-vector form factor of the pion provides a platform to study systematic effects and the chiral extrapolation for observables connected to the structure of mesons (and baryons). Mesonic form factors are computationally simpler than their baryonic counterparts but share most of the systematic effects. This thesis contains a comprehensive study of the form factor in the regime of low momentum transfer $q^2$, where the form factor is connected to the charge radius of the pion. A particular emphasis is on the region very close to $q^2=0$ which has not been explored so far, neither in experiment nor in LQCD. The results for the form factor close the gap between the smallest spacelike $q^2$-value available so far and $q^2=0$, and reach an unprecedented accuracy at full control over the main systematic effects. This enables the model-independent extraction of the pion charge radius. The results for the form factor and the charge radius are used to test chiral perturbation theory ($\chi$PT) and are thereby extrapolated to the physical point and the continuum. The final result in units of the hadronic radius $r_0$ is rn$$ \left\langle r_\pi^2 \right\rangle^{\rm phys}/r_0^2 = 1.87 \: \left(^{+12}_{-10}\right)\left(^{+\:4}_{-15}\right) \quad \textnormal{or} \quad \left\langle r_\pi^2 \right\rangle^{\rm phys} = 0.473 \: \left(^{+30}_{-26}\right)\left(^{+10}_{-38}\right)(10) \: \textnormal{fm} \;, $$rn which agrees well with the results from other measurements in LQCD and experiment. Note, that this is the first continuum extrapolated result for the charge radius from LQCD which has been extracted from measurements of the form factor in the region of small $q^2$.rnrnThe order of the phase transition in the chiral limit of two-flavour QCD and the associated transition temperature are the last unkown features of the phase diagram at zero chemical potential. The two possible scenarios are a second order transition in the $O(4)$-universality class or a first order transition. Since direct simulations in the chiral limit are not possible the transition can only be investigated by simulating at non-zero quark mass with a subsequent chiral extrapolation, guided by the universal scaling in the vicinity of the critical point. The thesis presents the setup and first results from a study on this topic. The study provides the ideal platform to test the potential and limits of todays simulation algorithms at finite temperature. The results from a first scan at a constant zero-temperature pion mass of about 290~MeV are promising, and it appears that simulations down to physical quark masses are feasible. Of particular relevance for the order of the chiral transition is the strength of the anomalous breaking of the $U_A(1)$ symmetry at the transition point. It can be studied by looking at the degeneracies of the correlation functions in scalar and pseudoscalar channels. For the temperature scan reported in this thesis the breaking is still pronounced in the transition region and the symmetry becomes effectively restored only above $1.16\:T_C$. The thesis also provides an extensive outline of research perspectives and includes a generalisation of the standard multi-histogram method to explicitly $\beta$-dependent fermion actions.

Quality control of virgin olive oils with regard to different storage and shipment conditions

Virgin olive oil(VOO) is a product characterized by high economic and nutritional values, because of its superior sensory characteristics and minor compounds (phenols and tocopherols) contents. Since the original quality of VOO may change during its storage, this study aimed to investigate the influence of different storage and shipment conditions on the quality of VOO, by studying different solutions such as filtration, dark storage and shipment inside insulated containers to protect it. Different analytical techniques were used to follow-up the quality changes during virgin olive oil storage and simulated shipments, in terms of basic quality parameters, sensory analysis and evaluation of minor components (phenolic compounds, diglycerides, volatile compounds). Four main research streams were presented in this PhD thesis: The results obtained from the first experimental section revealed that the application of filtration and/or clarification can decrease the unavoidable quality loss of the oil samples during storage, in comparison with unfiltered oil samples. The second section indicated that the virgin olive oil freshness, evaluated by diglycerides content, was mainly affected by the storage time and temperature. The third section revealed that fluctuation in temperature during storage may adversely affect the virgin olive oil quality, in terms of hydrolytic rancidity and oxidation quality. The fourth section showed that virgin olive oil shipped inside insulated containers showed lower hydrolytic and oxidation degradation than those without insulation cover. Overall, this PhD thesis highlighted that application of adequate treatment, such as filtration or clarification, in addition to a good protection against other external variables, such as temperature and light, will improve the stability of virgin olive oil during storage.