Presynchronization with Double-Ovsynch improves fertility at first postpartum artificial insemination in lactating dairy cows

The objective of this study was to compare circulating progesterone (P4) profiles and pregnancies per AI (P/AI) in lactating dairy cows bred by timed artificial insemination (TAI) following Ovsynch-56 after 2 different presynchronization protocols: Double-Ovsynch (DO) or Presynch-Ovsynch (PS). Our main hypothesis was that DO would increase fertility in primiparous cows, but not in multiparous cows. Within each herd (n = 3), lactating dairy cows (n = 1,687; 778 primiparous, 909 multiparous) were randomly assigned to DO [n = 837; GnRH-7d-PGF_2α-3d-GnRH-7d-Ovsynch-56 (GnRH-7d-PGF_2α-56h-GnRH-16hTAI)] or PS (n = 850; PGF_2α-14d-PGF_2α-12d-Ovsynch-56). In 1 herd, concentrations of P4 were determined at the first GnRH (GnRH1) of Ovsynch-56 and at d 11 after TAI (n = 739). In all herds, pregnancy was diagnosed by palpation per rectum at 39 d. In 1 herd, the incidence of late embryo loss was determined at 74 d, and data were available on P/AI at the subsequent second service. Presynchronization with DO reduced the percentage of animals with low P4 concentrations (<0.50 ng/mL) at GnRH1 of Ovsynch-56 (5.4 vs. 25.3%, DO vs. PS). A lesser percentage of both primiparous and multiparous cows treated with DO had low P4 concentrations at GnRH1 of Ovsynch-56 (3.3 vs. 19.7%, DO vs. PS primiparous; and 8.8 vs. 31.9%, DO vs. PS multiparous). Presynchronization with DO improved P/AI at the first postpartum service (46.3 vs. 38.2%, DO vs. PS). Statistically, a fertility improvement could be detected for primiparous cows treated with DO (52.5 vs. 42.3%, DO vs. PS, primiparous), but only a tendency could be detected in multiparous cows (40.3 vs. 34.3%, DO vs. PS, multiparous), consistent with our original hypothesis. Presynchronization treatment had no effect on the incidence of late embryo loss after first service (8.5 vs. 5.5%, DO vs. PS). A lower body condition score increased the percentage of cows with low P4 at GnRH1 of Ovsynch-56 and reduced fertility to the TAI. In addition, P4 concentration at d 11 after TAI was reduced by DO. The method of presynchronization at first service had no effect on P/AI at the subsequent second service (34.7 vs. 36.5%, DO vs. PS). Thus, presynchronization with DO induced cyclicity in most anovular cows and improved fertility compared with PS, suggesting that DO could be a useful reproductive management protocol for synchronizing first service in commercial dairy herds.     

Characterization of solid embeddable reference electrodes for corrosion monitoring in reinforced concrete structures

Metal-metal oxide (MMO), graphite and laboratory-made Ag/AgCl electrodes were electrochemically characterized to be used as reference electrodes embedded in concrete structures. Electrodes were studied in both, aqueous solutions of pH ranging from 7 to 13.5 and embedded into cement mortars; and the electrochemical studies were carried out in the absence and presence of chloride ions. Potential evolution, polarization behaviour, galvanostatic pulse response and impedance characteristics of the electrodes were carried out in aqueous solutions. Besides, the electrochemical stability of the electrodes embedded in mortar was studied for an exposure period of 2 years. It was found that the MMO pseudo-reference electrode is pH-sensitive, the graphite pseudo-reference electrode is oxygen sensitive and the Ag/AgCl pseudo-reference electrode is chloride sensitive. In spite of the fact that any of them can be used to determine the corrosion rates of rebars because they do not depend on the absolute potential and/or the long-term stability of the reference electrode when using traditional electrochemical techniques, long-term drifts in the electrode potentials may lead to misinterpretations of the rebar state. In this context graphite electrodes are recommended because they provide conservative results regarding the active/passive state of the rebars.     

Zinc‐based compounds as smoke suppressant agents for an aerospace epoxy matrix

Smoke is considered to be the main hazard of fires involving epoxy resins but its production depends on many variables, principally the chemical character and the burning rate of the polymer plus the availability of oxygen. The work reported aimed to study the smoke suppressant effect and flammability performance of zinc‐based compounds (FR system) in epoxy matrix composites used in the aerospace and aeronautical industry. The flammability performance of neat and FR‐loaded systems was screened using microcombustion calorimetry, while smoke generation, in terms of carbon monoxide (CO) and carbon dioxide (CO₂) production, was analysed under dynamic conditions using cone calorimetry. Final results indicate that the dispersion of zinc borate and zinc hydroxystannate (ZHS) into epoxy matrices leads to a significant variation in flame retardant properties reducing both total heat release by about 25 and 30%, respectively, and heat release capacity by about 30 and 50%, respectively. The system containing ZHS shows an enhancement in all smoke suppressant properties; both tin compounds (zinc stannate (ZS) and ZHS) give a reduction of CO₂/CO ratio from 41 to 25 for ZS and from 41 to 36 for ZHS compared to neat matrix. Copyright © 2010 Society of Chemical Industry     

Synthesis of crystalline metal nitride and metal carbide nanostructures by sol–gel chemistry

Attention toward nanosized metal nitrides and carbides is rapidly increasing thanks to their chemical characteristics that make them as valid and sustainable alternatives to noble metals in catalysis and to air-sensitive metals or oxides for applications under harsh conditions. They are mostly used as bulk phase or micron sized powders, due to an intrinsic difficulty to synthesize them as nanoparticles in a systematic and scalable fashion. However, nanosized metal nitrides and carbides could exhibit improved performances, e.g. in catalysis due to a higher surface area, and can be shaped more easily than corresponding larger grains for further specific applications. Recently, sol–gel chemistry has closed this gap and now enables the simple, cheap, and sustainable production of metal nitride and carbide nanoparticles.In the present review we give an overview on recent sol–gel based pathways for the synthesis of metal nitride and carbide nanoparticles, believing that a better knowledge of the potentialities of these still hardly touched materials stimulates research interest and applications.     

The influence of Pt on the electrooxidation behaviour of carbon in phosphoric acid

The electrooxidation behaviour of Pt/C catalysts for phosphoric acid fuel cells (PAFC) has been investigated by potentiostatic tests in the potential range 0.6 ÷ 1.0 V (rhe). Results indicate that the corrosion rate increases with an increase in Pt content, and is most noticeable at 0.6 V. At higher potentials anodic dissolution of Pt takes place, thus no metal is available to catalyze the corrosion of carbon. It is concluded that a definite influence of the presence of the supported metal on the extent of carbon corrosion under practical conditions does exist, but the understanding of mechanisms involved in the Pt-promoted carbon corrosion requires further studies.     

Evaluation of the cochlear aqueduct patency: comparison of 2 noninvasive techniques

Variations in cephalo-rachidian fluid pressure can be transmitted to the middle ear through the cochlear aqueduct (CA). This gives us a non-invasive manner to evaluate any changes in fluid pressure by measuring middle ear impedance (impedancemetry). The present study compared two indirect methods for measuring intracranial pressure: a) impedancemetry during evoked jugulo-tympanic reflex (JTR) and b) study of the tympanic membrane (TM) fine motility using a MMS-10 analyzer. The latter is a new procedure involving the indirect evaluation of the fluid pressure. In fact, when the CA is open the labyrinthine fluid pressure is transmitted to the oval window, the stapes platina and, finally, to the tympanic membrane where it can be measured with an MMS-10 unit. This equipment can measure nanoliter shifts in the TM. In particular, comparison between the clinostatic and orthostatic tympanic motility measurements enable one to establish whether the CA is patent or not. In the present study 15 subjects were examined using both a) impedancemetry during jugular compression and b) analysis of the TM shift using an MMS-10 unit. In 14 of the 15 cases there was good correlation between the data obtained using both methods: in all but one case it proved possible to record a JTR-induced variation in impedance whenever the MMS-10 indicated that the CA was open. The results suggest that, in clinical practice, the two methods can be used in parallel for non-invasive monitoring of variations in intracranial pressure in patients with neurological involvement. On the other hand, in the E.N.T. field these techniques could be used to study inner ear pathologies causing dynamic alterations of the endolabyrinth fluids (endolymphatic hydrops, labyrinthine fistula).     

Critical Temperature Tuning of Ti/TiN Multilayer Films Suitable for Low Temperature Detectors

We present our current progress on the design and test of Ti/TiN multilayer for use in kinetic inductance detectors. Sensors based on sub-stoichiometric TiN film are commonly used in several applications. However, it is difficult to control the targeted critical temperature \(T_c\) , to maintain precise control of the nitrogen incorporation process and to obtain a production uniformity. To avoid these problems we investigated multilayer Ti/TiN films that show a high uniformity coupled with high quality factor, kinetic inductance and inertness of TiN. These features are ideal to realize superconductive microresonator detectors for astronomical instruments application but also for the field of neutrino physics. Using pure Ti and stoichiometric TiN, we developed and tested different multilayer configurations, in terms of number of Ti/TiN layers and in terms of different interlayer thicknesses. The target was to reach a critical temperature \(T_c\) around \((1{\div } 1.5)\)  K in order to have a low energy gap and slower recombination time (i.e. low generation–recombination noise). The results prove that the superconductive transition can be tuned in the \((0.5{\div } 4.6)\)  K temperature range by properly choosing the Ti thickness in the \((0{\div } 15)\)  nm range, and the TiN thickness in the \((5{\div } 100)\)  nm range.     

Study of the IC443 SNR with the Fermi LAT

During the first six months of data taking the Fermi satellite was capable to detect gamma ray emission of the nearby supernova remnant IC443 (G189.1+3.0). IC443 is a shell-type supernova remnant located in the anticenter region where observation can be made clean enough from possible foreground and background overlap, even though care has to be taken due to the vicinity of one of the brightest gamma-ray pulsars, Geminga. IC443 estimated age (20–30 kyr) and the observed two-shell morphology with different radii suggest that the SNR shell has been interacting with surrounding interstellar matter and a neighboring SNR shell. Also the detection of strong molecular emission lines and TeV gamma-ray emission support the idea that the blast has been interacting with dense molecular gas accelerating cosmic-ray particle. After the first year of data taking, Fermi will be surely capable to determine the spatial extension and resolve in much finer details the spectral shape of the gamma-ray emission produced by the accelerated cosmic rays in IC443 distinguished from those of galactic origin.     

Delivery of chemotropic proteins and improvement of dopaminergic neuron outgrowth through a thixotropic hybrid nano-gel

Chemotropic proteins guide neuronal projections to their final target during embryo development and are useful to guide axons of neurons used in transplantation therapies. Site-specific delivery of the proteins however is needed for their application in the brain to avoid degradation and pleiotropic affects. In the present study we report the use of Poly (ethylene glycol)-Silica (PEG-Si) nanocomposite gel with thixotropic properties that make it injectable and suitable for delivery of the chemotropic protein semaphorin 3A. PEG-Si gel forms a functional gradient of semaphorin that enhances axon outgrowth of dopaminergic neurons from rat embryos or differentiated from stem cells in culture. It is not cytotoxic and its properties allowed its injection into the striatum without inflammatory response in the short term. Long term implantation however led to an increase in macrophages and glial cells. The inflammatory response could have resulted from non-degraded silica particles, as observed in biodegradation assays.