bluuebunny/crossref_metadata_2025 huggingface dataset:
A hybrid encryption scheme based on optical scanning cryptography and Fibonacci–Lucas transformation
Authors: Cyriac A. Meril , M. K. B. Sheeja
Published: January 2021

This paper describes a new opto-hybrid technique of two-stage encryption for the secure transmission and reception of sensitive information contained in the form of images and data. An advanced encryption–decryption technique based on optical scanning holography (optical scanning cryptography) and Fibonacci–Lucas transformation is proposed. The first stage of this hybrid system includes a point spread function engineered optical scanning cryptographic system. A new key based on fused biometric array is used in this stage. A digital encryption strategy follows this stage. This hybrid encryption scheme can be used for the secure transfer and storage of medical images in the Internet, especially in cloud-based services. The quantitative analysis is performed using different figure of merits. The quantitative investigations have been conducted through computer simulations. The parameters analyzed for establishing the performance characteristics of this system are Structural Similarity Index, Correlation Coefficient, Maximum Absolute Deviation, etc. This system shows a remarkable performance improvement during encryption. The method can be explicitly used in the radiograph image transfer over the Internet for telemedicine applications.
Resonant-type piezoelectric inertial drive mechanism with asymmetric inertial masses
Authors: Pan Chengliang , Shi Chao , Feng Anhui , Hu Mingang , Shu Shuangbao , Xia Haojie
Published: January 2021

Resonant-type piezoelectric impact motors can improve the output capability effectively. A new construction of asymmetric inertial masses is proposed to synthesize approximate saw-tooth wave resonant vibration with matched anti-phase and in-phase modes. A prototype is designed, manufactured, and tested. With 40 Vp–p, 400 Hz exciting voltage for the anti-phase mode and 16 Vp–p, 800 Hz exciting voltage for the in-phase mode, the prototype provides a maximum no-load velocity of 17.2 mm/s and a maximum output power of 0.72 mW with 100 mN load. The velocity and output power of the prototype in the proposed resonant state are near three orders of magnitude higher than those in the traditional quasi-static state.
Dynamics of plasma formation and gas heating in a focused-microwave discharge in nitrogen
Authors: Saifutdinov A. I. , Kustova E. V.
Published: January 2021

A self-consistent extended fluid-dynamic model describing a focused microwave discharge in a molecular gas is developed, and numerical simulations of the formation of plasmoids in nitrogen in an experimentally operating cylindrical paraboloid focusing system are carried out. It is shown that, depending on the input power and gas pressure, plasmoids ranging from one to four can be formed. The main spatial–temporal parameters of the plasmoid formed at the main focus of the system are studied in the active phase and in the afterglow phase. The main channels of gas heating in the domain of plasmoid formation are investigated. The importance of taking into account gas heating in the self-quenching reactions of excited nitrogen molecules, both in the active phase and in the first microseconds of the afterglow phase, is shown. The main mechanism at long times in the afterglow phase is the release of energy in vibrational–translational relaxation.
The effects of turbulence and pressure gradients on vorticity transport in premixed bluff-body flames
Authors: Rising Cal J. , Morales Anthony J. , Geikie Marissa K. , Ahmed Kareem A.
Published: January 2021

The current study experimentally evaluates the effects of turbulence and pressure gradients on vorticity transport in premixed bluff-body flames. The flow field pressure gradient is modified using a variable-geometry test section. In tandem, a custom-designed turbulence generator is used to modulate the turbulence intensity in the test section. The objective of the combined pressure gradient and turbulence tailoring is to alter the balance between the individual terms of the vorticity transport equation and ultimately identify the subsequent impacts on the overall behavior of the flame and flow field. Simultaneous high-speed particle image velocimetry and CH* chemiluminescence are employed to measure the turbulent reacting flow field. The vorticity dynamics are analyzed using a mean, conditionally filtered, fluid element tracking method to calculate individual terms of the vorticity transport equation as fluid elements evolve across the flame front. The analysis shows that increasing the pressure gradient increases the reacting vorticity production for all vorticity terms. In contrast, the overall vorticity budget, or relative contribution of each vorticity term, is much more sensitive to turbulence effects. At low turbulence conditions, vorticity is dominated by baroclinic torque, regardless of the pressure gradient. As the turbulence intensity is increased, the exothermic effects of baroclinicity and dilatation are diminished, and the reacting flow field approaches that of a non-reacting turbulent flow. The relative balance of vorticity transport terms is shown to influence the overall flow field, as well as the structure and evolution of the flame front.
Hydrodynamic focusing in porous media and its ramifications on the critical penetration depth
Authors: Comiskey P. M. , Staszel C.
Published: January 2021

The effect of hydrodynamic focusing through a surface with multiple pores is investigated. The flow field of a single drop impacting a surface with n number of pores is established by solving the Laplace equation as a result of an instantaneous pressure impulse with complex analysis. The liquid velocity penetrating into the pores is derived and applied to find the critical penetration depth at which the impacting liquid ceases motion. It was found that the liquid penetration velocity rapidly diminishes as the number of pores increases. Implications for liquids splashing onto garments and the corresponding critical thickness such that liquid does not completely penetrate are discussed.
Ferrimagnetic insulators for spintronics: Beyond garnets
Authors: Emori Satoru , Li Peng
Published: January 2021

Ferrimagnetic insulators have gained much attention as material platforms with efficient magnetization dynamics. To date, epitaxial iron garnet thin films are the most widely used materials in the emerging field of “insulator spintronics.” However, further advances in this field require overcoming the disadvantages of garnets—e.g., their complex structure, high growth temperature, incompatibility with other crystalline materials, and relatively weak perpendicular magnetic anisotropy. In this Perspective, we make the case that epitaxial thin films of spinel ferrites and hexagonal ferrites are viable materials for insulator spintronics with complementary advantages over the oft-used garnets. Specifically, spinel ferrites have a simpler structure, can crystallize at lower temperatures, and are more amenable to coherent integration with various materials; hexagonal ferrites possess enormous perpendicular anisotropy of bulk origin, in contrast to garnets where the strength of anisotropy is restricted by interfacial strain. The expanded repertoire of materials for insulator spintronics will enable new physical insights and potential applications, beyond what is currently possible with garnets.
Robust data assimilation with noise: Applications to cardiac dynamics
Authors: Marcotte Christopher D. , Fenton Flavio H. , Hoffman Matthew J. , Cherry Elizabeth M.
Published: January 2021

Reconstructions of excitation patterns in cardiac tissue must contend with uncertainties due to model error, observation error, and hidden state variables. The accuracy of these state reconstructions may be improved by efforts to account for each of these sources of uncertainty, in particular, through the incorporation of uncertainty in model specification and model dynamics. To this end, we introduce stochastic modeling methods in the context of ensemble-based data assimilation and state reconstruction for cardiac dynamics in one- and three-dimensional cardiac systems. We propose two classes of methods, one following the canonical stochastic differential equation formalism, and another perturbing the ensemble evolution in the parameter space of the model, which are further characterized according to the details of the models used in the ensemble. The stochastic methods are applied to a simple model of cardiac dynamics with fast–slow time-scale separation, which permits tuning the form of effective stochastic assimilation schemes based on a similar separation of dynamical time scales. We find that the selection of slow or fast time scales in the formulation of stochastic forcing terms can be understood analogously to existing ensemble inflation techniques for accounting for finite-size effects in ensemble Kalman filter methods; however, like existing inflation methods, care must be taken in choosing relevant parameters to avoid over-driving the data assimilation process. In particular, we find that a combination of stochastic processes—analogously to the combination of additive and multiplicative inflation methods—yields improvements to the assimilation error and ensemble spread over these classical methods.
Transverse-mode control in VCSELs by electrically tunable liquid crystal mode filters
Authors: Shao Hongyan , Guan Baolu , Cui Lijie , Cui Ning , Zhang Yang , Zeng Yiping
Published: January 2021

A distinctive method is used to achieve transverse-mode control by building and integrating a tunable liquid crystal (LC) mode filter on top of traditional vertical-cavity surface-emitting lasers (VCSELs). An LC cell is fabricated by injecting a type of nematic LC material (E7) in an annular groove patterned by SiO2. By electrically tuning the refractive index of the LC, a spatially dependent reflectivity profile can be achieved and optimized, which directly influences the threshold modal gain of each transverse mode provided by oxide-confined VCSELs. The flexible and accurate control performance of the LC mode filter structure have been demonstrated by the simulation results and our analysis. This design is a completely novel method to realize VCSELs with an accurate and real-time controllable transverse-mode, and it will probably play a significant role in the future.
Correlated cation lattice symmetry and oxygen octahedral rotation in perovskite oxide heterostructures
Authors: Chen P. F. , Lan D. , Liu C. , Wu X. H. , Khandelwal A. , Li M. S. , Li C. J. , Yang P. , Yu X. J. , Chen J. S. , Pennycook S. J. , Ariando A. , Huang Z. , Chow G. M.
Published: January 2021

Recent studies have highlighted the collective rotations of corner-shared oxygen octahedra in ABO3 functional perovskite oxides. However, experimental methods that allow direct measurements of oxygen octahedra, especially for the multilayer containing different types of oxygen octahedral rotations in each layer, are still rare. In this report, the correlation between oxygen octahedral rotation and cation-lattice symmetry is discussed by studying the interface-engineered perovskite La2/3Sr1/3MnO3 layers. The out-of-phase octahedral rotations remove the orthogonality between corresponding axes of the cation lattice, leading to the asymmetric diffraction pattern recorded by the reciprocal space mapping. More importantly, in the La2/3Sr1/3MnO3-multilayer heterostructure, the reciprocal space mapping can identify different octahedral rotations for each La2/3Sr1/3MnO3 layer, explaining the appearance of multiple Curie temperatures and coercive fields. Our results reveal the new understanding of the old reciprocal space mapping-based technique, based on the correlation between oxygen octahedral rotation and cation-lattice symmetry. The application of reciprocal space mapping to the La2/3Sr1/3MnO3-multilayers not only showcases the advantage of this technique but also extends our understanding of oxygen octahedral rotation to the more complicated oxide heterostructures.
Solution processable poly(vinylidene fluoride)-based ferroelectric polymers for flexible electronics
Authors: Li Qingqing , Zhao Jinghua , He Baosheng , Hu Zhijun
Published: January 2021

Since the discovery of piezoelectricity in poly(vinylidene fluoride) (PVDF) 50 years ago, ferroelectric polymers have established their own areas for research and applications due to their unique properties in comparison to single crystals and inorganics. PVDF is a semicrystalline polymer that can crystallize into five different polymorphs. Among them, the polar β-phase is the most interesting one for electroactive properties because it has the highest dipolar moment and the highest piezoelectric response. In the early days, the β-PVDF was typically produced by melt processing, limiting its form to free-standing films. The rapid development of flexible electronics, however, highly requires β-PVDF fabricated from solutions under mild conditions. The objective of this perspective is to summarize the effective methods to produce β-PVDF from solution, to present the approaches for enhancing the electroactive properties through morphological controls, and to discuss the applications of PVDF-based ferroelectric polymers in flexible electronics. In addition, current challenges that may impede the further development of this field are pointed out.
Air bubbles play a role in shear thinning of non-colloidal suspensions
Authors: Lin Yuan , Wang Ying , Weng Zixin , Pan Dingyi , Chen Jiawang
Published: January 2021

Shear thinning of non-colloidal suspensions involving multi-scaled air bubbles is studied. It is observed that the presence of bubbles significantly affects the transition and equilibrium rheological behavior. Large bubbles enhance shear thinning of the system by increasing the particle loading at low shear rates, whereas nano-bubbles suppress shear thinning by introducing additional repulsive interactions between smooth solid spheres, which also hinder the shear thinning of the polymeric matrix at high shear rates. As to the transition behavior at low shear rates caused by the particle organization, nano-bubbles induce a more diffusive particle motion, leading to a larger critical strain accounting for the finish of the organization process. It shows that nano-bubbles shield the interaction between solid spheres. Therefore, a degassing process prior to the rheological experiment is essential in order to achieve reliable rheological properties of the two-phase suspension system.
High-speed operation of single-mode tunable quantum cascade laser based on ultra-short resonant cavity
Authors: Zhou Yuhong , Liu Junqi , Zhai Shenqiang , Zhuo Ning , Zhang Jinchuan , Liu Shuman , Wang Lijun , Liu Fengqi , Wang Zhanguo
Published: January 2021

We have demonstrated a room temperature, low power consumption, high-speed, and single-mode tunable quantum cascade laser at λ ∼ 4.6 µm. Combining a 300 µm buried hetero-structure ultra-short cavity with optimized facet coatings, a single-mode tuning range covering ∼40 nm is obtained at room temperature under low electrical power consumption below 1.1 W. The single-mode emission is observed with more than 25 dB side mode suppression ratio in the whole tuning range. The high frequency modulation is achieved with a microwave package, resulting in the −3 dB cutoff frequency of 5.6 GHz.
Diverse novel analytical and semi-analytical wave solutions of the generalized (2+1)-dimensional shallow water waves model
Authors: Chu Yuming , Khater Mostafa M. A. , Hamed Y. S.
Published: January 2021

This article studies the generalized (2 + 1)-dimensional shallow water equation by applying two recent analytical schemes (the extended simplest equation method and the modified Kudryashov method) for constructing abundant novel solitary wave solutions. These solutions describe the bidirectional propagating water wave surface. Some obtained solutions are sketched in two- and three-dimensional and contour plots for demonstrating the dynamical behavior of these waves along shallow water. The accuracy of the obtained solutions and employed analytical schemes is investigated using the evaluated solutions to calculate the initial condition, and then the well-known variational iterational (VI) method is applied. The VI method is one of the most accurate semi-analytical solutions, and it can be applied for high derivative order. The used schemes’ performance shows their effectiveness and power and their ability to handle many nonlinear evolution equations.
Calculation of the flow velocity of a siphon
Authors: Zheng Jun , Guo Jichao , Wang Jiongchao , Zhang Yingqiu , Lü Qing , Sun Hongyue
Published: January 2021

Siphons have been known and used since ancient times and are still widely used. We re-examine the siphon process and recognize that the existing classic formula of the flow velocity of a siphon is only applicable to continuous flow; however, the flow of a siphon may be discontinuous flow. This study proposes new formulas, which can cover continuous and discontinuous flow and can consider the influence of the release of air from liquid on the flow velocity. Sixteen experiments were performed to validate our proposed method. The main results show that (a) for some schemes, the calculated values from the existing formula have large errors and the maximum error rate reaches 96%, (b) our method not only calculates the flow velocity of a siphon well but also makes a good prediction of the bubbles observed in the experiments, and (c) Qup/Qw > 1 is an effective way to reduce bubble generation in a siphon pipe, where Qup and Qw are the volumetric flow rates of the liquid phase by analyzing the upward pipe and whole pipe using Bernoulli’s equation, respectively. Based on the above understanding, some new siphon systems could be designed to reduce bubble generation in a siphon; for example, a new siphon drainage system with variable diameters can be designed to reduce bubble generation and, hence, to weaken or even avoid cavitation in the process of a siphon.
Parameter identification of Preisach model based on velocity-controlled particle swarm optimization method
Authors: Chen Long , Yi Qiongyang , Ben Tong , Zhang Zeyu , Wang Youhua
Published: January 2021

The Preisach model is widely used to simulate the magnetic performance of transformers and motors in industrial applications. However, its parameter identification problem is still a complicated task. This paper proposed a new parameter identification method based on the velocity-controlled particle swarm optimization (VCPSO) algorithm combined with the closed-form Everett function. Firstly, the Preisach model is built through the closed-form Everett function, which gives an explicit form Preisach model. Secondly, the Preisach model’s parameter identification is realized by using the VCPSO algorithm, which only needs the limiting static hysteresis loop of the material. During the optimization process, the particle velocity is automatically adjusted to avoid falling into the optimal local solution. Finally, the obtained results are compared with the experimental hysteresis loop of the B30P150 silicon steel.
Domain structure and energy losses up to 10 kHz in grain-oriented Fe-Si sheets
Authors: Magni A. , Sola A. , de la Barrière O. , Ferrara E. , Martino L. , Ragusa C. , Appino C. , Fiorillo F.
Published: January 2021

We investigate in theory and experiment the frequency dependence of magnetic losses in Grain-Oriented 0.29 mm thick high-permeability steel sheets up to 10 kHz. Such an unusually broad frequency range, while responding to increasing trends towards high-frequency regimes in applications, is conducive to a complex evolution of the magnetization process, as imposed by increasing frequencies to a non-linear high-permeability saturable material. We show that the concept of loss decomposition, supported by observations of the domain wall dynamics through Kerr experiments, is effective in the assessment of the broadband frequency dependence of the energy loss. By calculating, in particular, the instantaneous and time averaged macroscopic induction profiles across the sheet thickness through the Maxwell’s diffusion equation, the classical loss component Wclass, versus frequency f and peak polarization Jp, is obtained. A simplified theoretical approach is pursued in this case by identifying the normal magnetization curve with the magnetic constitutive equation of the material. While the hysteresis loss Whyst is shown to invariably increase with frequency, the excess loss Wexc, the quantity directly associated with the eddy currents circulating around the moving domain walls, tends to vanish upon increasing both frequency and induction values. The Kerr experiments actually show that, while the oscillating 180° domain walls can adjust to the depth of the induction profile by bowing at low Jp values, the magnetization reversal at high inductions and high frequencies occurs by inward motion of symmetric fronts originating at the sheet surface, according to a classical framework.
105 Increasing fertility of interspecific hybrid males using biotechnological approaches
Authors: Vetokh A. , Tadzhieva A. , Iolchiev B. , Volkova N. , Bagirov V.
Published: January 2021

The results of AI depend on many factors, with the quality of semen being one of the most important. Not all male hybrids can meet the requirements for semen quality, because they often have reduced fertility following cryopreservation. Thus, it is necessary to improve semen processing before use in AI. The aim of the study was to evaluate the effectiveness of using the “swim-up” flotation method to improve sperm quality of hybrid males of the Ovis genus. Semen from interspecific hybrid rams (1/4 Argali×3/4 Romanov, n=15; 1/8 Argali×7/8 Romanov, n=15) was freshly obtained, frozen–thawed, and processed by the swim-up method. Evaluation of sperm motility was determined using computer-assisted semen analysis. Statistical analysis was performed using SPSS vs.15.0 (ANOVA and t-test; SPSS Inc.). Semen was collected during the breeding season (October–December) via artificial vagina. Assessment of acrosome integrity was determined using differential staining with a Diachem diff-quick kit (NPF ABRIS+). The degree of sperm DNA fragmentation was determined using the acridine-orange test. The sperm freezing/thawing cycle was accompanied by sperm damage and an increase in the proportion of immobile sperm from 10 to 58%, with non-progressive movement increasing from 9 to 19.3%. The number of spermatozoa with abnormal morphology doubled, and the DNA fragmentation index increased from 16 to 26%. Use of the swim-up procedure allowed us to sort progressively motile spermatozoa. The content of progressively motile spermatozoa in the samples obtained from the supernatant was 86%, which was 2.3 times higher than in frozen–thawed sperm (P≤0,01). The obtained results show the effective use of the swim-up procedure to determine the quality of semen in hybrid rams.
These studies were carried out with financial support from the Russian Science Foundation, grant No. 18-16-00079 and the Ministry of Science and Higher Education of the Russian Federation.
112 Follicular dynamics and oestrus response of Alpine goats with oestrus/ovulation synchronized during the early transitional reproductive phase using gonadotrophin given early or late
Authors: Loetz E. , Rojas M.
Published: January 2021

Oestrus and ovulation synchronization (E/OS) regimens for fixed-timed breeding are useful when consistently eliciting ovulation. Early synchronization in the reproductive season promotes unreliable oestrus behavioural and physiologic response due to insufficient ovarian priming. In ruminants, equine (eCG) or human chorionic gonadotrophin (hCG) has FSH bioactivity or elicits ovulation, correspondingly. Hence, 120 and 60IU of eCG and hCG, respectively, are included in goat E/OS regimes. This experiment addresses the time when eCG/hCG (CG) is given relative to progestagen (P4) withdrawal and its effect on oestrus and ovulation. Fourteen non-lactating, Alpine breed goats, ranging from 1 to 6 kiddings, averaging±s.d. 3.9±2.0 years of age, and 56.3±5.0kg of bodyweight (BW), and body condition score (BCS) of 2.6±0.2, were evaluated early in the transitional reproductive phase (12h daylight:12h darkness). E/OS was accomplished with 12 day of P4 (200 mg) exposure by intravaginal insert. Three treatments were evaluated: Traditional (T; n=4) did not receive CG and served as the control group; early (E; n=5) received CG 24h before P4 removal; and reverse (R; n=5) received PGF2α 24h before P4 withdrawal as well as CG concurrent with P4 withdrawal. Oestrus response to E/OS was evaluated 24h after breeding using epididymectomized bucks. Ovaries were scanned by transrectal ultrasound (Aloka SSD-500V/7.5-MHz linear array probe) for 4 consecutive days starting with the first i.m. injection of 1.0mL of PGF2α or 1.5mL of CG. Images were digitized (MediCapture™) for later morphometry. The absence of effect (P>0.05) from concomitant variables age, BW, BCS, and parity was ascertained using a logistic regression model (JMP/SAS v15; SAS Institute Inc.). Ovulation, defined as the disappearance of the largest (>7mm) preovulatory follicle on a subsequent observation, was 100, 80, and 100%; and the average±s.e. number of ovulations per goat was 2±0.41, 1±0.32, and 1.3±0.49 (P>0.05). Table 1 summarises follicular size documented of 122 observations of ovulatory areas. Graafian follicle location was not different for left or right ovaries (P>0.05). Oestrus behavioural response to each E/OS treatment (T, E, or L) up to 24h after P4 removal was 50, 80, and 80% (P>0.05), respectively. In summary, oestrus response and ovulation were not affected by the variables studied. In this experience the timing of CG was not relevant.

Table 1.
Mean diameter (±SE; mm) of nonovulatory and preovulatory follicles on left (L) and right (R) ovaries

E/OS protocol
Non- and preovulatory
Nonovulatory
Preovulatory

L
R
L
R
L
R

Traditional
6.4±0.6
5.5±0.6
4.8±0.4
4.5±0.4
7.7±0.4
8.9±0.3

Early
5.2±0.3
5.5±0.4
4.9±0.2
4.4±0.3
8.4±1.2
8.1±0.2

Reverse
6.6±0.5
5.3±0.6
5.1±0.4
4.4±0.5
8.7±0.3
8.1±0.2

Overall
5.7±0.19
4.7±0.14
8.3±0.14
116 Differences between 5- and 6-day progestogen-based oestrus induction protocol in Saanen and Toggenburg goats
Authors: Pinheiro J. B. S. , Souza-Fabjan J. M. G. , Correia L. F. L. , Oliveira M. E. F. , Fonseca J. F.
Published: January 2021

Hormonal oestrus induction treatment is an important tool for the success of reproductive biotechniques in anoestrus goats. In the nonbreeding season, oestrus induction can be performed by the use of several protocols, including those varying in their duration. This study aimed to compare short-term (for either 5 or 6 days) progestogen-based oestrus synchronization protocols in dairy [Toggenburg (n=12) and Saanen (n=12)] goats during the nonbreeding season. This study was performed in Minas Gerais State, Brazil (21°35′S and 43°15′W), with 12 nulliparous (12–14 months old) and 12 pluriparous (2–4 years old in final third of lactation) goats, all with body condition scores (BCS) of 3.0 to 3.5. They were equally assigned to both treatments according to their order of parturition, BCS, and breed. On a random day (Day 0), 24 goats received an intravaginal device of 60mg of medroxyprogesterone acetate (Progespon®, Zoetis) which remained for 5 (G5; n=12) or 6 (G6; n=12) days. On Day 5, goats from both groups received 30µg of cloprostenol intramuscularly (IM) (Prolise®, ARSA S.R.L.) and 200IU of equine chorionic gonadotrophin (eCG) IM (Novormon®, Schering Plough Animal Health). Both groups received cloprostenol and eCG on the same day (regardless of device removal) to ensure they were administered at the same follicular wave. Both device insertion and removal were performed in the morning. Ultrasound evaluations were performed every 12h from device removal to ovulation detection. Ovulations were considered as the average interval between the last observation of follicles and the first exam in which it was no longer seen. The normal distribution of variables was determined by Shapiro-Wilk test and homocedasticity by Levene’s test. All variables were not normally distributed and thus analysed by Mann–Whitney U test, with P<0.05 considered significantly different. Values are presented in median±interquartile range. There was no difference between G5 and G6, respectively, in the interval to oestrus (48.0±0.0 vs. 48.0±12.0h), interval from oestrus onset to ovulation (18.0±9.0 vs. 18.0±12.0h), interval from device removal to ovulation (66.0±18.0 vs. 66.0±24.0h), number of ovulated follicles (2.0±2.0 vs. 2.5±2.0), or mean diameter of ovulated follicles (6.6±1.6 vs. 6.6±1.4mm). All ovulations were detected in the morning. In conclusion, our data demonstrate that short-term hormonal treatment for 5 or 6 days is similarly efficient to induce synchronous oestrus in Saanen and Toggenburg goats.
This research was supported by EMBRAPA (Project 20.19.01.004.00.03.001) and CNPq (314952/2018-7).
127 Metabolomics analysis of human cumulus cells from oocytes exhibiting different developmental competence
Authors: Martínez-Moro Á. , Lamas-Toranzo I. , Bermejo-Álvarez P.
Published: January 2021

Cumulus cells play fundamental metabolic roles during folliculogenesis, being closely connected to the oocyte through transzonal projections. These oocyte-supporting cells are removed and discarded before intracytoplasmic sperm injection (ICSI), thereby constituting an interesting biological material on which to perform molecular analyses aimed to predict oocyte developmental potential. The objective of this study was to determine the possible differences in the amount of biochemical compounds in human cumulus cells from oocytes exhibiting different developmental competence: (1) oocytes not developing to blastocyst following ICSI (Bl−), (2) oocytes developing to blastocyst but failing to establish pregnancy following embryo transfer (P−), and (3) oocytes developing to blastocyst able to establish a pregnancy (P+). Cumulus cells were removed following conventional chemical and mechanical treatments before ICSI. Following cell dissociation, cumulus cells from individual oocytes were pelleted by centrifugation at 1500×g for 10min, snap frozen in liquid nitrogen, and kept at −80°C until analysis. Once the developmental potential was known, metabolomics analysis was performed in 12 samples per group, each composed of cumulus cells attached to an individual oocyte. Metabolomics analyses were performed by Metabolon Inc., which provides unbiased metabolite analyses based on ultra-high-performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS). Welch’s two-sample t-test was used to identify biochemicals that differed significantly between groups (P<0.05). The analysis identified 97 compounds of known identity in human cumulus cells, excluding xenobiotics. Of these, only 3 showed significant differences between groups: (1) cysteine, more abundant (1.5-fold increase) in P− compared with Bl−; (2) erythronate, more abundant (1.25-fold increase) in P+ compared with Bl−; and (3) malonate, more abundant (1.55-fold increase) in Bl− compared with P−. No differences were found in other comparisons for these compounds, although tendencies (0.05 < P <0.1) were noted for cysteine (1.68-fold increase in P+ vs. P−) and malonate (1.92-fold increase in P− vs. P+). These results suggest that metabolomics analysis of human cumulus cells provides a poor predictive value for the developmental potential of the enclosed oocyte.
130 Expression of selected biomarker candidate genes to confer invitro maturation in Indian buffaloes
Authors: Doultani S. , Mootapally C. , Nathani N. , Suthar V. , Highland H. , Patil D. , Joshi M. , Joshi C.
Published: January 2021

Invitro maturation (IVM) of oocytes is a crucial step and is directly related to better embryo production in buffaloes. Therefore, we planned to study gene expression of GDF9, HAS2, SPRY1, ARHGAP22, COL18A1, and GPC4 genes in IVM and immature cumulus–oocyte complexes (COCs). The COCs were recovered from follicles of slaughter origin ovaries of native buffaloes. COCs were observed under stereo zoom microscope and categorized in four grades according to morphology. Of the four grades, the first three grade COCs were considered and randomly allotted in two groups: immature treatment group (n=263) and IVM treatment group (n=272). IVM of COCs was carried out in 100-μL drops of BO-IVM medium overlaying embryo tested oil in a 35-mm petri dish under 5% CO2 in a 39.0°C incubator for 24h. Cumulus of COCs of both groups were removed by treating with 0.25% trypsin, and oocytes were stored in RNALater for future use. The expression of genes was evaluated using quantitative PCR, and the relative expression of each gene was calculated using the ΔΔCt method with efficiency correction. The logarithmic transformation of fold change (log2FC) of each candidate gene in the IVM oocyte group was computed against the immature oocyte group based on the observed cycle threshold values. Appropriate standard deviations were determined based on the observed deviations among the triplicates. The expression in the IVM treatment group of previously reported upregulated genes (GDF9, HAS2, SPRY1) was higher (up to 10-fold) compared with the immature treatment group (reference group). In the present study, relatively lower expression was observed for the other candidate genes (ARHGAP22, COL18A1, GPC4) in the bovine transcripts of oocyte, which were previously also reported as being downregulated.
132 Influence of oocyte retrieval methods and maturation media on invitro development of polar body extrusion in pig oocytes
Authors: Honneysett K. M. , Mphaphathi M. L. , Maqhashu A. M. , Webb E. C.
Published: January 2021

Oocyte recovery is a reproductive technology that can be done by using two techniques, aspiration and slicing. Invitro maturation (IVM) is an additional reproductive technology used to advance an oocyte to a maturation stage; thereafter, it may be used during IVF. The objectives of the present study were (1) to compare two different oocyte retrieval methods (aspiration and slicing) from pig ovaries on oocyte quality and quantity, and (2) to compare three different IVM media [NCSU 37, TCM-199, and modified porcine follicular fluid (mpFF=porcine follicular fluid+FSH+LH] on oocytes’ polar body extrusion. During aspiration, an 18G needle was attached to a 10-mL syringe and all visible follicles were aspirated. During slicing, a surgical blade was used to slice the ovaries held in mDPBS. Follicular fluid collected from both methods was assessed for the presence of oocytes with the aid of a microscope. The collected oocytes were then categorized as Grade A, B, or C: Grade A=oocytes with compacted, multilayered cumulus cells and a homogeneous ooplasm; Grade B=oocytes with a compact cumulus cell layer with homogeneous ooplasm; Grade C=oocytes with a less compact cumulus cell layer with irregular ooplasm containing dark granules. The IVM media were placed in a four-well multidish; thereafter Grades A and B oocytes were allocated per treatment groups and matured for 44h. The treatment means were compared using the Fisher’s protected t-test least significant difference. The results showed significant differences between the grades of oocytes (P<0.05) with Grade A and B oocytes accounting for 50.8% of total oocytes (193.8) for aspiration and 58.7% of total oocytes (488.6) for slicing. The oocytes polar body extrusion was recorded as 25.3, 84.2, and 73.8% for NCSU 37 (P<0.05) and TCM-199 and mpFF respectively (P>0.05). In conclusion, the slicing method proved to be better than aspiration with regards to the retrieval of Grades A and B oocytes as well as the total number of oocytes retrieved. The TCM-199 and mpFF media had a higher percentage of oocytes with polar body extrusion than NCSU 37.
134 Trichostatin A as an aging agent during invitro fertilization in pig oocytes
Authors: Arena H. A. , Hicks E. C. , Sprungl K. N. , Reynolds S. B. , Whitaker B. D.
Published: January 2021

An aged oocyte is one that was not fertilized during the optimal time window after ovulation and potentially has diminished fertilization and embryonic development success. Oocytes (n=2562) were matured with or without trichostatin A (TSA; 100ng mg−1), a known meiotic inhibitor, for 24 or 48h (OMI), then for an additional 16h (OMII) without TSA or hormones. Oocytes were measured for meiosis before maturation (n=95), after OMI (n=365), and after OMII (n=230) as well as cumulus cell expansion (CCE). Oocytes (n=800) were fertilized with frozen–thawed boar sperm and potential embryos were evaluated for IVF characteristics and cleavage and blastocyst formation 48 and 144h after IVF, respectively. Apoptosis was determined in the maturing oocytes by levels of reactive oxygen species (ROS; n=476), mitochondrial electrochemical potential gradient dissipation (n=405), caspase 3 (n=405), phosphatidylserine (n=453), and DNA breakdown (n=192). Data were analysed by ANOVA and Tukey’s test. Oocytes matured without TSA for 48h had a significantly higher (P<0.05) percentage of oocytes at the MI stage of meiosis compared to all other treatment groups (16.00±6.80) and oocytes matured without TSA for 24h had a significantly higher (P<0.05) percentage of oocytes at the MII stage of meiosis compared to all other treatment groups (14.7±11.30). Oocytes matured with or without TSA for 48h had significantly less (P<0.05) CCE compared to oocytes matured without TSA for 24h. Supplementation of TSA to OMI significantly decreased (P<0.05) fertilization penetration rates compared with not supplementing TSA for 24h. Percent of embryos cleaved by 48h and those reaching blastocyst by 144h after IVF were significantly higher (P<0.05) in oocytes matured for 24h compared with those matured for 48h. Oocytes matured without TSA for 24h generated significantly different (P<0.05) levels of ROS compared with oocytes matured with TSA for 48h. Oocytes matured without TSA for 48h had significantly higher (P<0.05) mitochondrial membrane potential compared with all other treatments. Levels of caspase 3 activation and phosphatidylserine (which translocates in response to apoptosis) differed (P<0.05) between treatments. Results from the TUNEL assay indicate oocytes matured through OMII with a short OMI and TSA supplemented (23.8±2.99%) and through OMI with a long OMI and TSA supplemented (24.3±1.11%) had significantly greater (P<0.05) percent of oocytes with fragmented DNA than the other treatments, except for oocytes matured through OMII with a long OMI and TSA supplemented (35.0±3.55%), which was significantly greater (P<0.05) than all other treatments. Results indicate that use of TSA to stimulate aging in pig oocytes is a valid and a reliable option.
137 Comparison of two invitro maturation media on polar body extrusion of cattle oocytes
Authors: Sithole S. M. , Mphaphathi M. L. , Sebopela M. D. , Nedambale T. L.
Published: January 2021

The invitro embryo production technique is one of the assisted reproduction technologies that has the potential in speeding up genetic improvement in cattle. The developmental competence of invitro-matured oocytes is influenced by several factors during invitro maturation (IVM), such as maturation environment, oocyte quality, type of media, and additives. The objective of the present study was to compare two IVM media (TCM-199 and BO-IVM) on cattle oocyte maturation rate invitro. Cattle ovaries were collected from local slaughterhouse and transported to the laboratory in a thermos flask containing 0.9% saline (Adcock Ingram Critical care) at 37°C. Oocytes were retrieved from the ovaries by the aspiration technique, and then matured invitro in 500µL of TCM-199 (supplemented with 10% fetal bovine serum, FSH, LH, and E2) or in 500µL of commercially available BO- IVM (Bioscience) medium, both covered with mineral oil for 22h at 38.5°C with 5% CO2 and 5% O2. After 22h of IVM, oocyte polar body extrusion was evaluated with the aid of Oosight Imaging System (Hamilton Thorne) connected to an inverted microscope. The total number of oocytes matured in TCM-199 and BO-IVM media were 401 and 396, respectively. The experiment was replicated 19 times. Data were analysed using the GenStat® program (VSN International). Means of different treatments were separated using Fisher’s protected t-test least significant difference at 5% level of significance. No difference was recorded for polar body extrusion rates in TCM-199 (50.6±13.9) and BO-IVM (47.3±13.7) media. In conclusion, TCM-199 and BO-IVM media did not differ in terms of maturation rate; thus, both can be used for successful cattle oocyte IVM.
141 Diet supplementation alters oocyte lipid content and developmental competence in mares
Authors: Catandi G. , Stokes J. , Maclellan L. , Broeckling C. , Carnevale E.
Published: January 2021

The equine oocyte is dense in lipids, which may serve as an energy source for oocyte maturation and later embryonic development. However, the association between lipid content and fertility remains to be determined, as does the extent that diet can modify oocyte lipids. We hypothesised that diet supplementation can alter the oocyte lipid profile and subsequent developmental potential. In Study 1, we examined if oocyte triglyceride (TG) relative abundance was affected by dietary supplementation. Mares (16–22 years, n=9) were fed grass/alfalfa hay and supplemented daily with a combination of commercially available feed additives designed to promote equine wellness and fertility [Equine GI™ (147g daily), Potency® (28g daily), Motility Plus® (23g daily), Healthy Weight Oil (60mL daily), Platinum Performance Inc.]. Oocytes were collected from the mares before (PRE) and after ≥8 weeks (POST) of supplementation during the natural breeding season. In Study 2, we compared oocyte developmental potential after injection of sperm into oocytes obtained from mares supplemented for ≥8 weeks with the same additives (ADD, 18–24 yr, n=5) or from a similar group of mares supplemented with a grain control diet (450g of grain mix and 60ml of corn oil daily, GRN, 19–23 years, n=5). Oocytes were collected from dominant follicles (≥35mm) during oestrus and at 20±2 h after induction of follicular maturation. In Study 1, oocytes were denuded of cumulus cells after collection, snap frozen, and assessed for TG composition by nontargeted liquid chromatography-mass spectrometry using an Acquity UPLC system (Waters). In Study 2, recovered oocytes were placed in maturation medium for 22±2h before being injected with sperm from one stallion, and blastocyst formation was assessed in 7 or 8 days. A total of 100 annotated TG species were identified. Normalized peak areas for PRE and POST oocyte TG were compared using two-tailed, paired t-tests. Blastocyst development rates were compared by Fisher’s exact test. Relative abundance of 71 TG species differed (P ≤ 0.05) between PRE and POST; all TG species as well as total relative abundance of TG were higher in oocytes from PRE compared with POST. Blastocyst rates per sperm-injected oocyte were greater (P=0.03) for ADD (40%, 6/15) than for GRN (5%, 1/19). Dietary supplementation of the complex mix of nutrients to middle-aged and older mares resulted in reduced relative abundance of TG in oocytes and improved developmental potential. We determined that oocyte lipid content can be modified through diet. The extent that diet supplementation improved oocyte competence by altering the lipid profile is still to be determined.
17 Increased inbreeding levels negatively affect sperm kinetics and motility in Purebred Spanish horses
Authors: Pirosanto Y. , Molina A. , Valera M. , Dorado J. , Terán E. , Azcona F. , Sebastian D. P.
Published: January 2021

Reproductive performance is one of the key factors in livestock production. It is well known that reproductive traits are influenced by several genetic factors, such as the increase of individual inbreeding levels, which are associated with changes in sperm motility and shape in several species. In horses, the increase in inbreeding is a common problem because of the reduction in effective population size and the increase in selection intensity observed in several breeds. However, studies assessing the effect of high levels of inbreeding on the sperm quality of stallions are scarce. In the present study, we aimed to determine the effect of increased inbreeding levels and age on the sperm motility patterns of Purebred Spanish horses (PRE). We performed kinetic characterisation of 557 sperm samples of 82 PRE stallions aged between 3 and16 years, using computer-assisted sperm analysis (Androvision™, Minitube). We evaluated 5 parameters in 6 different fields per sample: curved line velocity (VCL, µm/s), velocity average path (VAP, µm/s), velocity straight line (VSL, µm/s), amplitude of lateral head displacement (ALH, µm), and beat-cross frequency (BCF, Hz). We determined the pedigree-based inbreeding coefficient (Fped) based on ∼300,000 PRE pedigree records to evaluate the inbreeding effect. Individuals were separated into 2 groups: highly inbred (n=339) and lowly inbred (n=218) according to an F value of 12.5%. Differences between groups were analysed using a generalized linear model. The analysis did not show significant differences (P>0.05) in the variables analysed with respect to the age of stallions. However, VAP, VCL, and AHL were lower in highly inbred than in lowly inbred animals (P<0.05), suggesting less velocity and amplitude of head displacement. In the case of BCF, no significant differences (P>0.05) were observed between the two study groups. In conclusion, age did not affect sperm quality parameters in the age group of stallions analysed. In addition, we demonstrated that high inbreeding coefficient reduced the mean velocity and trajectory pattern of spermatozoa in PRE.