bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions between intersubunit transmembrane domains regulate the chaperone-dependent degradation of an oligomeric membrane protein
Authors: Buck Teresa M. , Jordahl Alexa S. , Yates Megan E. , Preston G. Michael , Cook Emily , Kleyman Thomas R. , Brodsky Jeffrey L.
Published: December 2016

In the kidney, the epithelial sodium channel (ENaC) regulates blood pressure through control of sodium and volume homeostasis, and in the lung, ENaC regulates the volume of airway and alveolar fluids. ENaC is a heterotrimer of homologous α-, β- and γ-subunits, and assembles in the endoplasmic reticulum (ER) before it traffics to and functions at the plasma membrane. Improperly folded or orphaned ENaC subunits are subject to ER quality control and targeted for ER-associated degradation (ERAD). We previously established that a conserved, ER lumenal, molecular chaperone, Lhs1/GRP170, selects αENaC, but not β- or γ-ENaC, for degradation when the ENaC subunits were individually expressed. We now find that when all three subunits are co-expressed, Lhs1-facilitated ERAD was blocked. To determine which domain–domain interactions between the ENaC subunits are critical for chaperone-dependent quality control, we employed a yeast model and expressed chimeric α/βENaC constructs in the context of the ENaC heterotrimer. We discovered that the βENaC transmembrane domain was sufficient to prevent the Lhs1-dependent degradation of the α-subunit in the context of the ENaC heterotrimer. Our work also found that Lhs1 delivers αENaC for proteasome-mediated degradation after the protein has become polyubiquitinated. These data indicate that the Lhs1 chaperone selectively recognizes an immature form of αENaC, one which has failed to correctly assemble with the other channel subunits via its transmembrane domain.
Dysphagia in the Aging Head and Neck Cancer Population
Authors: Lazarus Cathy
Published: December 2016

This article reviews the types of swallow impairment and side effects seen after head and neck cancer treatment. Treatments include surgery, specifically, oral and oropharyngeal cancer surgery, partial laryngectomy, total laryngectomy, and primary chemoradiotherapy. Normal changes to the swallowing mechanism with age are discussed, including potential negative effects on swallowing and outcomes. Other variables that can have an impact on swallow function and quality of life in older head and neck cancer patients are discussed including sensory changes, depression, and presence of a partner.
Low‐complexity precoding for MIMO channels with finite alphabet input
Authors: Cao Kuo , Wu Yongpeng , Yang Weiwei , Cai Yueming , Cao Kuo
Published: December 2016

Low‐complexity precoding design without iteration for multiple‐input multiple‐output channels with finite alphabet input is studied. Contrast to the iterative gradient method for finding the globally optimal precoder, which is time‐consuming and computationally complicated, this work studies low‐complexity precoding design with high performance. The problem of optimising the mutual information is identical to maximising the minimum Euclidean distance of the input vector at high total power. Hence, the precoding design can be formulated as semi‐definite programming problem and thus can be optimally solved. Numerical examples show that the proposed scheme achieves good tradeoff between the computational complexity and high performance compared with the conventional counterparts.
Non‐cooperative interference alignment for multicell multiuser MIMO uplink channels
Authors: Pham Khanh , Lee Kyungchun
Published: December 2016

Linear interference alignment (IA) is considered a promising interference management technique for future cellular networks. However, its application to practical cellular networks still faces many challenges, two of which are the overhead of sharing global channel state information (CSI) and the cost of signalling dimensionality. These two challenges are resolved in this study via a new linear IA scheme that not only prevents global CSI sharing but also keeps the number of signalling dimensions manageable. While making linear IA more applicable, the proposed scheme provides comparable degrees of freedom to the existing IA schemes in symmetric multicell multiuser multiple‐input multiple‐output (MIMO) uplink channels.
Polarisation reconfigurable, centre‐fed, and low‐profile Archimedean spiral antennas with unidirectional broadside patterns
Authors: Mehrabani Ali , Shafai Lotfollah
Published: December 2016

A low‐profile, dual circularly polarised, and centre‐fed four‐arm Archimedean spiral antenna with broadside radiation patterns is investigated in this paper. It is shown that both right‐ and left‐hand circular polarisations (CPs) are generated in the four‐arm spiral antenna, whose circumference is less than three wavelengths, by properly exciting the spiral arms from their inner ends. Similar analogy can be used to extend the concept to any multi‐arm spiral antenna. The proposed compact antenna, which is backed by a planar reflector surface, is designed and extensively investigated to study main antenna specifications including gain, cross polarisation, and pattern symmetry, for dual‐polarised wireless communication systems. A 3 dB axial ratio frequency bandwidth of about 1.8–5.3 GHz is realised for both clockwise and counter‐clockwise CP with axial beams. Furthermore, superior pattern symmetry with equal beamwidths is attained for both senses of polarisation. A prototype antenna is fabricated and tested. Excellent agreement between the measured and computed results is observed. An asymptotic equation is also developed to estimate the antenna peak gain over the frequency band for both senses of CPs.
DSTATCOM employing hybrid neural network control technique for power quality improvement
Authors: Panda Kumar Anup , Mangaraj Mrutyunjaya
Published: December 2016

A new hybrid control technique called gradient descent back propagation (GDBP)‐based for a three phase two‐level distribution static compensator (DSTATCOM) to perform the functions such as harmonic mitigation, power factor correction under reactive loads, which further reduces the DC link voltage across the self‐supported capacitor of voltage source converter (VSC). The weighted value of fundamental active and reactive components of load currents are extracted using the proposed control technique to generate the reference source currents. Furthermore, these currents are used to trigger the VSC of the DSTATCOM. The effectiveness of this control technique is demonstrated through simulation using MATLAB/SIMULINK and sim power system tool boxes. The real‐time implementation of DSTATCOM is also realised by real‐time digital simulator. These results reveal the robustness of the proposed DSTATCOM as it is showing outstanding harmonic compensation capabilities under the various loading conditions and keeping the total harmonics distortion of the source current well <5%, the limit imposed by IEEE‐519 standard.
Remote Cerebellar Hemorrhage Following Lumboperitoneal Shunt Insertion: A Rare Case Report
Authors: Ayvalık Fatih , Ozay Rafet , Turkoglu Erhan , Balkan Mehmet , Şekerci Zeki
Published: December 2016

Idiopathic intracranial hypertension is characterized by high intracranial pressure without hydrocephalus or intracranial mass. Surgical treatment includes optic nerve fenestration and insertion of ventriculoperitoneal and lumboperitoneal (LP) shunts. For decreasing intracranial pressure, cerebrospinal fluid (CSF) LP shunt is widely used for the surgical management; it also carries complications such as shunt migration, venous sinus thrombosis, subarachnoid hemorrhage, and subdural and intracerebral hematoma. A 52-year-old man was admitted to the neurosurgery clinic with severe headache, retro-orbital pain, and blurred vision. Lumbar puncture demonstrated that the CSF opening pressure was 32 cm H2O. A nonprogrammable LP shunt with two distal slit valves was inserted. Shortly after the surgery, his condition deteriorated and he became comatose. Immediate computed tomography scan revealed cerebellar hemorrhage and acute hydrocephalus. Development of remote cerebellar hemorrhage following LP shunt is rare. We discuss this rare event and the applicable literature.
Numerical simulations of the ablative Rayleigh-Taylor instability in planar inertial-confinement-fusion targets using the FastRad3D code
Authors: Bates J. W. , Schmitt A. J. , Karasik M. , Zalesak S. T.
Published: December 2016

The ablative Rayleigh-Taylor (RT) instability is a central issue in the performance of laser-accelerated inertial-confinement-fusion targets. Historically, the accurate numerical simulation of this instability has been a challenging task for many radiation hydrodynamics codes, particularly when it comes to capturing the ablatively stabilized region of the linear dispersion spectrum and modeling ab initio perturbations. Here, we present recent results from two-dimensional numerical simulations of the ablative RT instability in planar laser-ablated foils that were performed using the Eulerian code FastRad3D. Our study considers polystyrene, (cryogenic) deuterium-tritium, and beryllium target materials, quarter- and third-micron laser light, and low and high laser intensities. An initial single-mode surface perturbation is modeled in our simulations as a small modulation to the target mass density and the ablative RT growth-rate is calculated from the time history of areal-mass variations once the target reaches a steady-state acceleration. By performing a sequence of such simulations with different perturbation wavelengths, we generate a discrete dispersion spectrum for each of our examples and find that in all cases the linear RT growth-rate γ is well described by an expression of the form γ=α [kg/(1+ϵ kLm)]1/2−βkVa, where k is the perturbation wavenumber, g is the acceleration of the target, Lm is the minimum density scale-length, Va is the ablation velocity, and ϵ is either one or zero. The dimensionless coefficients α and β in the above formula depend on the particular target and laser parameters and are determined from two-dimensional simulation results through the use of a nonlinear curve-fitting procedure. While our findings are generally consistent with those of Betti et al. (Phys. Plasmas 5, 1446 (1998)), the ablative RT growth-rates predicted in this investigation are somewhat smaller than the values previously reported for the same target and laser parameters. It is speculated that differences in the equation-of-state and opacity models are largely responsible for the discrepancy. Resolution of this issue awaits the development of better experimental diagnostics capable of measuring small-wavelength (5–20 μm) perturbation growth due to the ablative RT instability in the linear regime.
Connecting point defect parameters with bulk properties to describe diffusion in solids
Authors: Chroneos A.
Published: December 2016

Diffusion is a fundamental process that can have an impact on numerous technological applications, such as nanoelectronics, nuclear materials, fuel cells, and batteries, whereas its understanding is important across scientific fields including materials science and geophysics. In numerous systems, it is difficult to experimentally determine the diffusion properties over a range of temperatures and pressures. This gap can be bridged by the use of thermodynamic models that link point defect parameters to bulk properties, which are more easily accessible. The present review offers a discussion on the applicability of the cBΩ model, which assumes that the defect Gibbs energy is proportional to the isothermal bulk modulus and the mean volume per atom. This thermodynamic model was first introduced 40 years ago; however, consequent advances in computational modelling and experimental techniques have regenerated the interest of the community in using it to calculate diffusion properties, particularly under extreme conditions. This work examines recent characteristic examples, in which the model has been employed in semiconductor and nuclear materials. Finally, there is a discussion on future directions and systems that will possibly be the focus of studies in the decades to come.
Simultaneous ohmic contacts to p- and n-type 4H-SiC by phase segregation annealing of co-sputtered Pt-Ti
Authors: Okojie R. S. , Lukco D.
Published: December 2016

A new concept, Phase Segregation Annealing (PSA), was investigated for implementing simultaneous ohmic contacts (SOCs) to p- and n-type 4H-SiC. Test structures with selected ratio compositions of co-sputtered Pt:Ti contacts were fabricated in p-type 4H-SiC epitaxial layers having aluminum acceptor concentrations, Na = 2 × 1019, 7 × 1019, and 2.5 × 1020 cm−3, and a nitrogen doped n-type epitaxial layer having donor concentration, Nd = 7 × 1018 cm−3. The ratios of the co-sputtered Pt-Ti metallization were 80:20, 50:50, and 30:70 at. %. After rapid thermal annealing (RTA) ranging between 800 and 1200 °C in vacuum and confirming SOCs by linear current-voltage (I-V) measurement, the specific contact resistance (ρc) values were extracted using the Transfer Length Measurement method. SOCs were realized with the Pt80:Ti20 composition starting from 1000 °C, and the Pt30:Ti70 composition from 1100 °C, with both exhibiting eutectic and segregated phases. The Pt50:Ti50 composition produced no SOC and eutectic and segregated phases were absent. The Pt80:Ti20 composition had the lowest pair of average ρc values of 7 × 10−5 Ω cm2 and 7.3 × 10−4 Ω cm2 on the highest doped p-type and the n-type samples after RTA at 1000 °C, respectively. Auger electron spectroscopy and focused ion beam field emission scanning electron microscopy with energy dispersive x-ray spectroscopy indicated distinct phase segregation via the eutectic-liquidus-eutectic transitions, the coalescence of likely Pt3Si and Pt2Si binary phases, and solid phases of Ti3Si, Ti5Si3, and TiC, with all the active phases maintaining intimate contact to both the p- and n-type 4H-SiC surfaces. The SOC formation was attributed to the disparate work functions of these phases, which was in good agreement with the proposed PSA model.
The stability of 1-D soliton in transverse direction
Authors: Verma Deepa , Bera Ratan Kumar , Das Amita , Kaw Predhiman
Published: December 2016

The complete characterization of the exact 1-D solitary wave solutions (both stationary and propagating) for light plasma coupled system have been studied extensively in the parameter space of light frequency and the group speed [Poornakala et al., Phys. Plasmas 9(5), 1820 (2002)]. It has been shown in 1-D that solutions with single light wave peak and paired structures are stable and hence long lived. However, solutions having multiple peaks of light wave are unstable due to Raman scattering instability [Saxena et al., Phys. Plasmas 14, 072307 (2007)]. Here, we have shown with the help of 2-D fluid simulation that single peak and paired solutions too get destabilized by the transverse filamentation instability. The numerical growth rates obtained from simulations is seen to compare well with the analytical values. It is also shown that multiple peaks solitons first undergo the regular 1-D forward Raman scattering instability. Subsequently, they undergo a distinct second phase of destabilization through transverse filamentation instability. This is evident from the structure as well as the plot of the perturbed energy which shows a second phase of growth after saturating initially. The growth rate of the filamentation instability being comparatively slower than the forward Raman instability this phase comes quite late and is clearly distinguishable.
Substrate selectivity in the low temperature atomic layer deposition of cobalt metal films from bis(1,4-di-tert-butyl-1,3-diazadienyl)cobalt and formic acid
Authors: Kerrigan Marissa M. , Klesko Joseph P. , Rupich Sara M. , Dezelah Charles L. , Kanjolia Ravindra K. , Chabal Yves J. , Winter Charles H.
Published: December 2016

The initial stages of cobalt metal growth by atomic layer deposition are described using the precursors bis(1,4-di-tert-butyl-1,3-diazadienyl)cobalt and formic acid. Ruthenium, platinum, copper, Si(100), Si–H, SiO2, and carbon-doped oxide substrates were used with a growth temperature of 180 °C. On platinum and copper, plots of thickness versus number of growth cycles were linear between 25 and 250 cycles, with growth rates of 0.98 Å/cycle. By contrast, growth on ruthenium showed a delay of up to 250 cycles before a normal growth rate was obtained. No films were observed after 25 and 50 cycles. Between 100 and 150 cycles, a rapid growth rate of ∼1.6 Å/cycle was observed, which suggests that a chemical vapor deposition-like growth occurs until the ruthenium surface is covered with ∼10 nm of cobalt metal. Atomic force microscopy showed smooth, continuous cobalt metal films on platinum after 150 cycles, with an rms surface roughness of 0.6 nm. Films grown on copper gave rms surface roughnesses of 1.1–2.4 nm after 150 cycles. Films grown on ruthenium, platinum, and copper showed resistivities of <20 μΩ cm after 250 cycles and had values close to those of the uncoated substrates at ≤150 cycles. X-ray photoelectron spectroscopy of films grown with 150 cycles on a platinum substrate showed surface oxidation of the cobalt, with cobalt metal underneath. Analogous analysis of a film grown with 150 cycles on a copper substrate showed cobalt oxide throughout the film. No film growth was observed after 1000 cycles on Si(100), Si–H, and carbon-doped oxide substrates. Growth on thermal SiO2 substrates gave ∼35 nm thick layers of cobalt(ii) formate after ≥500 cycles. Inherently selective deposition of cobalt on metallic substrates over Si(100), Si–H, and carbon-doped oxide was observed from 160 °C to 200 °C. Particle deposition occurred on carbon-doped oxide substrates at 220 °C.
Dispersion in a broadband terahertz quantum cascade laser
Authors: Bachmann Dominic , Rösch Markus , Scalari Giacomo , Beck Mattias , Faist Jérôme , Unterrainer Karl , Darmo Juraj
Published: December 2016

We present dispersion data of a broadband terahertz quantum cascade laser with a heterogeneous active region. The experimental method to extract the group velocity dispersion of the entire laser cavity, including the contributions of the active region, the semiconductor material, and the waveguide relies on a time-domain spectroscopy system. The obtained group velocity dispersion curves exhibit oscillations with amplitudes up to 1 × 105 fs2/mm between 2.0 and 3.0 THz and strongly depend on the driving conditions of the laser. This indicates that the group velocity dispersion is mainly determined by the intersubband gain in the active region. The obtained dispersion data are compared to a dispersion model based on multiple Drude-Lorentz gain media yielding a significant correlation.
Reaping the benefits of ferroelectricity in selectively precipitated lithium niobate microcrystals in silica matrix for photocatalysis
Authors: Rastogi Monisha , Chauhan Aditya , Kushwaha Himmat Singh , Kumar Ramachandran Vasant , Vaish Rahul
Published: December 2016

Microcrystals of LiNbO3 (size ∼200 nm) can be selectively precipitated in a glass matrix which can assist in the photocatalytic activity through ferroelectricity. Glass with the composition 30SiO2-35Li2CO3-35Nb2O5 was utilized for the process. A remarkably high Estriol (E3) degradation rate of 232.54 min−1 m−2 was obtained. The degradation was monitored using fluorescence spectroscopy with a detection limit in nanomolar (nM) range. From the fitting of fluorescence intensity versus time, it was observed that degradation of estriol follows a pseudo first-order reaction kinetics. The results indicate that LiNbO3 based glass-ceramics have a great potential to be employed as a well embedded photocatalyst.
Exciton delocalization incorporated drift-diffusion model for bulk-heterojunction organic solar cells
Authors: Wang Zi Shuai , Sha Wei E. I. , Choy Wallace C. H.
Published: December 2016

Modeling the charge-generation process is highly important to understand device physics and optimize power conversion efficiency of bulk-heterojunction organic solar cells (OSCs). Free carriers are generated by both ultrafast exciton delocalization and slow exciton diffusion and dissociation at the heterojunction interface. In this work, we developed a systematic numerical simulation to describe the charge-generation process by a modified drift-diffusion model. The transport, recombination, and collection of free carriers are incorporated to fully capture the device response. The theoretical results match well with the state-of-the-art high-performance organic solar cells. It is demonstrated that the increase of exciton delocalization ratio reduces the energy loss in the exciton diffusion-dissociation process, and thus, significantly improves the device efficiency, especially for the short-circuit current. By changing the exciton delocalization ratio, OSC performances are comprehensively investigated under the conditions of short-circuit and open-circuit. Particularly, bulk recombination dependent fill factor saturation is unveiled and understood. As a fundamental electrical analysis of the delocalization mechanism, our work is important to understand and optimize the high-performance OSCs.
Memory operations in Au nanoparticle single-electron transistors with floating gate electrodes
Authors: Azuma Yasuo , Sakamoto Masanori , Teranishi Toshiharu , Majima Yutaka
Published: December 2016

Floating gate memory operations are demonstrated in a single-electron transistor (SET) fabricated by a chemical assembly using the Au nanogap electrodes and the chemisorbed Au nanoparticles. By applying pulse voltages to the control gate, phase shifts were clearly and stably observed both in the Coulomb oscillations and in the Coulomb diamonds. Writing and erasing operations on the floating gate memory were reproducibly observed, and the charges on the floating gate electrodes were maintained for at least 12 h. By considering the capacitance of the floating gate electrode, the number of electrons in the floating gate electrode was estimated as 260. Owing to the stability of the fabricated SET, these writing and erasing operations on the floating gate memory can be applied to reconfigurable SET circuits fabricated by a chemically assembled technique.
Nonlinear frequency shift in Raman backscattering and its implications for plasma diagnostics
Authors: Kaganovich D. , Hafizi B. , Palastro J. P. , Ting A. , Helle M. H. , Chen Y.-H. , Jones T. G. , Gordon D. F.
Published: December 2016

Raman backscattered radiation of intense laser pulses in plasmas is investigated for a wide range of intensities relevant to laser wakefield acceleration. The weakly nonlinear dispersion relation for Raman backscattering predicts an intensity and density dependent frequency shift that is opposite to that suggested by a simple relativistic consideration. This observation has been benchmarked against experimental results, providing a novel diagnostic for laser-plasma interactions.
Electrical characteristics of MoSe2 TFTs dependent on the Al2O3 capping layer
Authors: Lee Hyunjea , Kim Ji Heon , Lee Cheol Jin
Published: December 2016

Back-gated MoSe2 thin-film transistors (TFTs) with an Al2O3-capping layer were fabricated, and the device characteristics of the MoSe2 TFTs that are dependent on the Al2O3-capping-layer passivation were investigated. The output drain current was doubled, the fluctuation of the output current was suppressed, and the threshold voltage of the MoSe2 TFTs was negatively shifted with the Al2O3-capping layer. The on/off-current ratio of the MoSe2 TFTs is approximately six decades regardless of the Al2O3-capping layer, but the field-effect mobility was greatly increased from 2.86 cm2/Vs to 10.26 cm2/Vs after the deposition of the Al2O3-capping layer. According to the results of this study, the Al2O3-capping layer can enhance the device characteristics of MoSe2 TFTs.
Chemistry Nobel honors mechanical bonds, molecular machines
Authors: Miller Johanna L.
Published: December 2016

The laureates laid the foundations for an emerging array of gadgets at the nanometer scale.
Exotic forms of silicon
Authors: Taylor P. Craig
Published: December 2016

The element’s complex free-energy landscape allows such structural motifs as rings, cages, and channel-like holes to emerge in extreme or unusual conditions.
Potato processing waste in beef finishing diets; effects on performance, carcass and meat quality
Authors: Duynisveld J. L. , Charmley E.
Published: December 2016

Potato by-products are frequently fed to cattle in many parts of the World. This paper considered the effect of feeding very high proportions of potato processing waste (PPW) to finishing beef cattle. One-hundred crossbred steers (Continental × British) were assigned to one of five finishing diets where rolled barley was replaced by PPW to give diets containing 0%, 20%, 40%, 60% or 80% PPW in the dry matter. Diets were fed ad libitum for 79, 107 or 135 days before steers were slaughtered and assessed for carcass and meat quality characteristics. Increasing the proportion of PPW in the diet resulted in a positive quadratic response in liveweight gain (P = 0.027). Inclusion level of PPW had no effect on carcass traits, although carcass weights declined linearly from 327 to 312 kg as PPW level in the diet increased (P = 0.016). Overall, effects of increasing the level of PPW on physical and sensory characteristics of meat were small and considered unlikely to affect consumer acceptance. Potentially due to inherent genetic variation in the cattle, some grew more slowly and were on feed for longer. Thus there was a linear decline in liveweight gain (P = 0.001) and a linear increase in grade fat (P = 0.039) as days to finish increased. Steers finished after 107 days had smaller loin eye area and lean meat yield, which resulted in negative quadratic effects for these characteristics (P = 0.014 and 0.024, respectively). We conclude that PPW can fully substitute for rolled barley in finishing diets without any negative implications for growth performance or meat quality and that the effect of days to finish were more important than the effect of the proportion of PPW in the diet.
Potential role of microRNAs in mammalian female fertility
Authors: Tesfaye Dawit , Salilew-Wondim Dessie , Gebremedhn Samuel , Sohel Md Mahmodul Hasan , Pandey Hari Om , Hoelker Michael , Schellander Karl
Published: December 2016

Since the first evidence for the involvement of microRNAs (miRNAs) in various reproductive processes through conditional knockout of DICER, several studies have been conducted to investigate the expression pattern and role of miRNAs in ovarian follicular development, oocyte maturation, embryo development, embryo–maternal communication, pregnancy establishment and various reproductive diseases. Although advances in sequencing technology have fuelled miRNA studies in mammalian species, the presence of extracellular miRNAs in various biological fluids, including follicular fluid, blood plasma, urine and milk among others, has opened a new door in miRNA research for their use as diagnostic markers. This review presents data related to the identification and expression analysis of cellular miRNA in mammalian female fertility associated with ovarian folliculogenesis, oocyte maturation, preimplantation embryo development and embryo implantation. In addition, the relevance of miRNAs to female reproductive disorders, including polycystic ovary syndrome (PCOS), endometritis and abnormal pregnancies, is discussed for various mammalian species. Most importantly, the mechanism of release and the role of extracellular miRNAs in cell–cell communication and their potential role as non-invasive markers in female fertility are discussed in detail. Understanding this layer of regulation in female reproduction processes will pave the way to understanding the genetic regulation of female fertility in mammalian species.
Emerging role of extracellular vesicles in communication of preimplantation embryos in vitro
Authors: Pavani Krishna C. , Alminana Carmen , Wydooghe Eline , Catteeuw Maaike , Ramírez Miguel A. , Mermillod Pascal , Rizos Dimitrios , Van Soom Ann
Published: December 2016

In vitro, efficient communication between mammalian embryos in groups or between embryos and cocultured somatic cells implies that there is a sender, a message and a receiver that is able to decode the message. Embryos secrete a variety of autocrine and paracrine factors and, of these, extracellular vesicles have recently been implicated as putative messengers in embryo–embryo communication, as well as in communication of the embryo with the maternal tract. Extracellular vesicles (EVs) are membrane-bound vesicles that are found in biofluids and in culture media conditioned by the presence of embryos or cells. EVs carry and transfer regulatory molecules, such as microRNAs, mRNAs, lipids and proteins. We conducted a systematic search of the literature to review and present the currently available evidence regarding the possible roles of EVs in in vitro embryo communication and embryo development. It is important to note that there is limited information available on the molecular mechanisms and many of the biologically plausible functions of EVs in embryo communication have not yet been substantiated by conclusive experimental evidence. However, indirect evidence, such as the use of media conditioned by embryos or by somatic cells with improved embryo development as a result, may indicate that EVs can be an important asset for the development of tailor-made media, allowing better embryo development in vitro, even for single embryo culture.
Effects of dry matter and energy intake on quality of oocytes and embryos in ruminants
Authors: Sartori Roberto , Spies Camila , Wiltbank Milo C.
Published: December 2016

The success of herd fertility involves the development of healthy follicles, viable oocytes and embryos capable of establishing and maintaining a pregnancy. Herein we discuss how nutrition interacts with reproduction throughout follicle development and pregnancy establishment, focusing on dry matter and energy intake. High feed intake, especially associated with moderate to high body condition, before and through superstimulation protocols, natural or induced single-ovulations or before ovum pick-up has detrimental effects on the quality of oocytes or embryos. Feed restriction or high energy supply can be used strategically to obtain either more or better quality oocytes or embryos. Altering diets that provide different concentrations of circulating insulin may improve ovarian status, oocyte quality, embryo development and pregnancy establishment and maintenance. Some sources of fat can positively affect reproductive performance, such as polyunsaturated fatty acids, improving embryo quality and pregnancy. In contrast, fat supplementation in the diet may compromise embryo cryotolerance. Finally, nutrition can alter concentrations of circulating or intrafollicular hormones and metabolites and the expression of genes in cattle oocytes and embryos. For an adequate feeding program to benefit reproductive performance, factors such as genetic group, source of energy, metabolic status, physiological status and level of feed intake must be taken into account.
154 COMPARISON OF DIFFERENT CULTURE MEDIA AND INCUBATION METHODS ON CULTURING MURINE EMBRYOS IN VITRO USING STRAW AS A RECEPTACLE
Authors: Madzhie L. R. , Raseona M. A. , Nethenzheni L. P. , Ajao O. , Mphaphathi M. L. , Barry D. M. , Nedambale T. L.
Published: December 2016

In vitro fertilization in the straw system might increase the efficiency of fertilization and the quality of blastocyst formation as compared with micro-drops-IVF systems. The aim of the study was to in vitro fertilize mouse oocytes and culture the resulting zygotes in bi-gas incubator and in a goat vagina and compare the in vitro embryo developmental stages in TCM-199 and Ham’s F10 culture media until the blastocyst-stage of development. F1 generations (Balb C × C57) were used to harvest oocytes and spermatozoa. The fresh sperm were capacitated in different incubation methods (bi-gas incubator and in the vagina of a goat). A volume of 2–4 µL of Ham’s F10 containing capacitated sperm (~8 × 106 per mL) were placed into Ham’s F10 fertilization drops under the oil, containing 10 oocytes and penicillamine, hypotaurine, and epinephrine for enhancing sperm motility and penetration of oocytes. The same procedure was used with the TCM-199 medium and IVF drops without oil (both TCM-199 and Ham’s F10) for straw filling. The presumptive embryos in Ham’s F10 and TCM-199 were divided into different groups: first group were cultured in micro-drops, second group the embryos were aspirated in semen straws and placed in the incubator (incubator straws) for culture, and other straws were covered with a sponge and inserted in the vagina of a goat (vaginal straws) for culture. The resulted blastocysts were stained using Hoechst 33528 solution and blastomeres were counted on a fluorescent UV light inverted microscope at 400× magnification (Nikon Eclipse TI, Narishige Co., Ltd., Amityville, NY, USA). The results were analysed by 2 × 2 factorial designs and Student’s t-test was used to separate the mean. There was no statistical difference (P > 0.05) between the media and incubators on the stage of murine embryo development. The overall fertilization rate was 94 to 99%. The incubator straws with Ham’s F10 (80.5%) had the highest rate of embryos that reached the blastocyst stage, followed by incubator straws with TCM-199 (77.0%), and vaginal straws with Ham’s F10 (60.0%) had the lowest rate of embryos that reached the blastocyst stage. The overall mean number of blastomeres in the blastocyst stage of the embryos ranged from 85 ± 9 to 90 ± 9 cells in all receptacles and incubators. It was concluded that the fertilization and culturing of murine embryos are possible in straws incubated in a bi-gas incubator and in the goat vagina as an alternative method of fertilizing oocytes and culturing murine embryos. In addition, Ham’s F10 and TCM-199 can both be used to fertilize oocytes and culture murine embryos until blastocyst formation embryo in vitro, incubated in a bi-gas incubator or in the vagina.
18 SEMENRATE: THE USE OF COMPUTER-ASSISTED SEMEN ANALYSIS AND FLOW CYTOMETRY FOR OBJECTIVE BOVINE SEMEN ANALYSIS IN THE UNITED KINGDOM
Authors: Spilman M. W. , Burton K. L. , Statham J. M. E.
Published: December 2016

Routine assessment of bovine semen consists of a subjective assessment of morphology, motility and concentration. This subjective approach used during quality control at semen production centres (SPC) or investigations of poor reproductive performance in veterinary practice has been shown to be relatively inaccurate, imprecise, and operator dependent (Vincent, et al. 2012 Anim. Reprod. 9, 153–165). Assessment of frozen semen samples in a dedicated laboratory aimed to establish variations in multiple parameters associated with fertility using computer-assisted semen analysis and flow cytometry and evaluate their relationship to semen performance in the field. This has developed into a commercial service that is available to veterinarians and farmers across the United Kingdom. AI semen from 50 farms across Yorkshire, UK, that had been stored on farm was assessed for factors associated with fertility (motility, progressive motility, intact acrosome, viability, and polarised mitochondria). Data ranges and mean values for each parameter have been analysed. This analysis is ongoing as the dataset continues to expand and significance will be assessed. For frozen semen (n = 79), % viable sperm (max = 67.64, min = 0.00, mean = 43.44), % sperm with polarised mitochondria (max = 72.50, min = 0.26, mean = 38.56), % sperm with acrosome intact (max = 68.82, min = 0.06, mean = 35.29), % motile sperm (max = 66.90, min = 0.00, mean = 37.44) and % progressively motile sperm (max = 59.00, min = 0.00, mean = 26.11). 25% of the samples fell below the cut off for release of 30% motile sperm set by SPCs. For sexed AI semen (n = 9), % viable sperm (max = 66.31, min = 17.08, mean = 43.57), % polarised mitochondria (max = 26.74, min = 13.40, mean = 19.96), % intact acrosome (max = 52.62, min = 15.34, mean = 37.00), % motile (max = 38.00, min = 9.40, mean = 24.88) and % progressively motile (max = 22.80, min = 3.90, mean = 13.15). Objective semen analysis before beginning an embryo collection programme allows informed decisions to be made regarding semen choice and dosage depending on compensable v. non-compensable defects detected (Hudson et al. 2012 Dairy Herd Health 73–111; CABI Publishing). Use of semen that falls below the 30% cut off for SPCs is unlikely to perform as expected in the field (Phillips et al. 2004 Anim. Reprod. Sci. 80, 47–61). A European collaboration aims to establish correlations between semen quality parameters and fertility outcomes for UK cattle herds, providing unique data for the industry (Sellem et al. 2015 Theriogenology 84, 1447–1454.e5). These data should highlight to stakeholders in the industry how imperative optimal semen quality is and highlight the benefits to herd fertility and financial performance.
186 SUPPLEMENTATION WITH LOW DOSES OF DIMETHYL SULFOXIDE DURING IN VITRO MATURATION RESULTS IN IMPROVED IN VITRO EMBRYO PRODUCTION IN CATTLE
Authors: Ynsaurralde A. E. , Suvá M. , Bevacqua R. , Munilla S. , Luchetti C. , Salamone D. F.
Published: December 2016

Oocyte in vitro maturation (IVM) is crucial for subsequent in vitro embryo production. It involves acquisition of competence for fertilization and embryo development. Therefore, its optimization could have a direct impact on in vitro embryo development. Dimethyl sulfoxide (DMSO) is commonly used as solvent or vehicle, but also increases the membrane permeability and behaves as a scavenger of cytotoxic free radicals. The aim of this study was to evaluate the effect of DMSO supplementation during bovine oocyte maturation on subsequent in vitro embryo development and to determine the optimal usage dose with no toxic effect. To this aim, cumulus-oocyte complexes were collected from slaughterhouse ovaries and IVM in TCM 199 containing 10% fetal bovine serum, 10 µg mL−1 of FSH, 0.3 mM sodium pyruvate, 100 mM cysteamine, and 2% antibiotic-antimycotic. The oocytes were incubated for 24 h at 6.5% CO2 in humidified air at 38.5°C. For Experiment 1, IVM medium was supplemented with DMSO at concentrations of 0, 0.1, 0.5, 1, or 10% (vol/vol) DMSO (n = 241, 195, 42, 192, 172 oocytes) and IVM rate was determined by presence of the first polar body. For Experiment 2, 0, 0.1, 0.25, 0.5, 0.75, 1, or 10% (vol/vol) DMSO (n = 446, 322, 65, 194, 77, 250, 39 oocytes) was supplemented to IVM medium and cleavage and blastocyst rates were determined to establish the optimal usage dose. In vitro fertilization was performed according to Brackett and Oliphant (1975), with 16 × 106 spermatozoa/mL for 5 h. Afterwards, presumptive zygotes were cultured in SOF for 7 days at 38.5°C and 5% O2. Cleavage and blastocyst rates were determined on Days 2 and 7, respectively. Results were statistically analysed using Fisher’s exact test by GraphPad Prism software (GraphPad Software Inc., La Jolla, CA, USA). Also, the percentage of blastocyst was adjusted to DMSO concentration using the R software quadratic regression model. The optimum usage dose was determined by calculating the maximum of the estimated predictive equation. In vitro maturation in 10% DMSO resulted in significantly lower first polar body extrusion rates (0% = 74%a, 0.1% = 73%a, 0.5% = 83%a, 1% = 66%a, and 10% = 8%b; different letters indicate statistical differences) and lower cleavage rates (0% = 75%a, 0.1% = 77%a, 0.25% = 80%a, 0.5% = 79%a, 0.75% = 78%a, 1% = 77%a, and 10% = 3%b) than the other treatments. Furthermore, blastocyst production was higher for the 0.25 and 0.5% (vol/vol) supplemented DMSO groups (0% = 26%b, 0.1% = 37%ab, 0.25% = 40%a, 0.5% = 41%a, 0.75% = 34%ab, 1% = 23%b, and 10% = 0%c). The predictive equation results indicate that the maximum percentage of blastocysts is obtained with a concentration of 0.458% (vol/vol) of DMSO. In conclusion, DMSO supplementation during IVM of bovine oocytes had a positive effect on in vitro development. Further studies will be carried out to elucidate its mechanism of action.
199 EFFECTS OF REPROGRAMMING-CONDITIONED MEDIUM ON ULTRAVIOLET RAY A–DAMAGED HUMAN DERMAL FIBROBLASTS
Authors: Kang J. , Lee S. G. , Kang J. H. , Park S.-M. , Heo S. Y. , Lee S. Y. , Kim S. , Lo E. , Ahn K. S. , Shim H.
Published: December 2016

Ultraviolet ray A (UVA) is an electromagnetic light with a long wavelength from the sun. The penetration of UVA deep into the human dermis causes changes in cells, such as DNA fragmentation, apoptosis, and senescence, eventually leading a decline of proliferation and wound-healing ability. These changes induced by UVA exposure are similar to those seen in the process of stem cell differentiation. We postulated that the condition that reverses cellular differentiation may alleviate the UVA-induced damage in skin cells. Human dermal fibroblasts (HDF) could be reprogrammed to induced pluripotent stem cells (iPSC). Conditioned medium (CM) was prepared during the process of iPSC reprogramming (referred to as Repro-CM). The UVA-irradiated HDF were cultured in Repro-CM for 24 h. In comparison with CM prepared from the culture of normal HDF and iPSC (referred to as HDF-CM and iPSC-CM, respectively), effects of Repro-CM on UVA-irradiated cells were investigated. Viability, wound-healing ability, apoptosis, and senescence of HDF were analysed by WST-1 assay, scratch assay, Annexin V assay, and senescence-associated β-galactosidase assay, respectively. Upon recovering from the UVA-induced damage, viability and wound-healing ability of HDF were significantly different (P < 0.05) among the treatments in the order of Repro-, HDF-, and iPSC-CM. In the same context, apoptosis and senescence were significantly different (P < 0.05) in the order of iPSC-, HDF-, and Repro-CM. Interestingly, iPSC-CM did not substantially ameliorate UVA-induced damage, suggesting that the conditions optimized to pluripotent stem cells may not be suitable for the recovery from damage in terminally differentiated cells, such as fibroblasts. The RNA-seq analysis was performed to assess the genome-wide transcriptional profile in the process of recovery. Repro- and HDF-CM were categorized more closely than iPSC-CM in hierarchical cluster analysis. In comparison with iPSC-CM, the up-regulated genes by Repro-CM treatment were related to regulation of cell proliferation and cell metabolism, whereas down-regulated genes were related to antiapoptosis and response to stimulation of chemical and organic substances. Overall, providing an environment of reprogramming, as shown by Repro-CM in the present study, may assist recovery of HDF from UVA-induced damage. The results of the study may be applicable in developing pharmaceuticals to treat aging and wrinkling of the skin caused by UVA irradiation.
31 EFFICIENT GENERATION OF klotho MUTATIONS IN PORCINE SOMATIC CELL NUCLEAR TRANSFER EMBRYOS USING A DELIVERY OF Cas9 RIBONUCLEOPROTEINS
Authors: Lee S. , Jung M. H. , Oh H. J. , Koo O.-J. , Lee B. C.
Published: December 2016

Pigs are useful models for studying human diseases because of the similarity of their anatomy and physiology. Recent advances in genome editing techniques such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeat-associated Cas9 system (CRISPR/Cas9) have made it possible to produce animals for specific purposes. Especially, recent application of the CRISPR/Cas9 system improved the efficiency of genome editing in pigs with higher targeting efficiency or percentage of desired mutation compared to other meganucleases (ZFNs and TALENs). The klotho deficiency in small animals such as mice is characterised by an extremely shortened life span with multiple aging-like phenotypes similar to human premature-aging syndromes. However, limited information is available on the function of klotho in large animals such as pigs. The objective of this study was to determine whether the use of non-selected porcine fibroblasts electroporated with Cas9/sgRNA ribonucleoproteins, targeting the klotho gene, for somatic cell nuclear transfer (SCNT) results in high mutation rates in embryos. A CRISPR sgRNA specific for the klotho gene was designed and sgRNA (targeting exon 3 of klotho) and type 2 Cas9 RNPs (total 36 μg, 1:4 ratio, respectively) were transfected into porcine fibroblasts via Neon (Life Technologies) with a single DC pulse of 1400 V for 30 ms. Then, transfected fibroblasts were cultured for 1 day and used randomly for SCNT without selection. SCNT was performed by enucleation of in vitro-matured porcine oocyte, followed by injection of non-selected donor cells, fusion with a single DC pulse of 200 V/mm for 30 μs using an electro cell fusion generator (LF101; Nepa Gene Co.), and electrical activation with a single DC pulse of 150 V/mm for 60 μs using a BTX Electro-Cell Manipulator 2001 (BTX Inc.). The SCNT embryos were cultured in PZM5 culture medium to Day 7 and analysed for the presence of modifications to the klotho gene. Blastocysts were classified as modified if they contained an INDEL as measured by both T7E1 assay and deep sequencing of PCR amplicons spanning the targeted exon. The klotho modification rate was 65% (n = 13), of which 38.5% (n = 5) of the embryos contained biallelic modifications. In conclusion, SCNT with non-selected donor cells transfected with Cas9/sgRNA RNPs might be an efficient and simple tool to produce klotho deficient pigs as models for human diseases. Further studies are required to generate klotho deficient pigs by performing embryo transfer to the recipients.
This study was supported by Korea Institute of Planning and Evaluation for Technology in food, agriculture, forestry and fisheries (#311011–05–5-SB010, #114059–03–2-SB010), Research Institute for Veterinary Science, TS Corporation and the BK21 plus program.