Identification of tea quality at different picking periods: A hyperspectral system coupled with a multibranch kernel attention network

The material content and nutritional composition of tea vary during different picking periods, leading to variations in tea quality. The absence of rapid evaluation methods for identifying tea quality at different picking periods hinders the smooth operation and maintenance of agricultural production and market sales. In this work, hyperspectral technology combined with the multibranch kernel attention network (MBKA-Net) is proposed to identify the overall quality of tea during different picking periods. First, spectral information of six different tea picking periods is obtained using a hyperspectral system. Second, the multibranch kernel attention (MBKA) method is proposed, which effectively mines spectral features through multiscale adaptive extraction and achieves classification of tea at different picking periods. Finally, MBKA-Net achieves outstanding performance with 96.18% accuracy, 97.14% precision, and 97.18% recall. In conclusion, MBKA-Net combined with a hyperspectral system provides an effective detection method for identifying the quality of tea at different picking periods.

Identification of white degradable and non-degradable plastics in food field: A dynamic residual network coupled with hyperspectral technology

In the food field, with the improvement of people's health and environmental protection awareness, degradable plastics have become a trend to replace non-degradable plastics. However, their appearance is very similar, making it difficult to distinguish them. This work proposed a rapid identification method for white non-degradable and degradable plastics. Firstly, a hyperspectral imaging system was used to collect the hyperspectral images of the plastics in visible and near-infrared bands (380-1038 nm). Secondly, a residual network (ResNet) was designed according to the characteristics of hyperspectral information. Finally, a dynamic convolution module was introduced into the ResNet to establish a dynamic residual network (Dy-ResNet) to adaptively mine the data features and realize the classification of the degradable and non-degradable plastics. Dy-ResNet had better classification performance than the other classical deep learning methods. The classification accuracy of the degradable and non-degradable plastics was 99.06%. In conclusion, hyperspectral imaging technology was combined with Dy-ResNet to identify the white non-degradable and degradable plastics effectively.

FBANet: An Effective Data Mining Method for Food Olfactory EEG Recognition

At present, the sensory evaluation of food mostly depends on artificial sensory evaluation and machine perception, but artificial sensory evaluation is greatly interfered with by subjective factors, and machine perception is difficult to reflect human feelings. In this article, a frequency band attention network (FBANet) for olfactory electroencephalogram (EEG) was proposed to distinguish the difference in food odor. First, the olfactory EEG evoked experiment was designed to collect the olfactory EEG, and the preprocessing of olfactory EEG, such as frequency division, was completed. Second, the FBANet consisted of frequency band feature mining and frequency band feature self-attention, in which frequency band feature mining can effectively mine multiband features of olfactory EEG with different scales, and frequency band feature self-attention can integrate the extracted multiband features and realize classification. Finally, compared with other advanced models, the performance of the FBANet was evaluated. The results show that FBANet was better than the state-of-the-art techniques. In conclusion, FBANet effectively mined the olfactory EEG data information and distinguished the differences between the eight food odors, which proposed a new idea for food sensory evaluation based on multiband olfactory EEG analysis.

A study on prenucleation and heterogeneous nucleation in liquid Pb on solid Al using molecular dynamics simulations

In this paper, we investigate prenucleation and heterogeneous nucleation in the liquid Pb/solid Al system as an example of systems with large lattice misfit using molecular dynamics simulation. Solid Pb and Al have a large positive lattice misfit (f) of 18.2% along the densely packed [110] direction. This study reveals that prenucleation occurs at 600 K (an undercooling of 15 K), and a 2-dimensional (2D) ordered structure forms at the interface with a coincidence site lattice (CSL) between the first Pb and first Al layers. The CSL accommodates the major part of the f, and only a small residual lattice misfit (f_r) of 1.9% remains. The formation of the CSL transforms the original substrate into a considerably potent nucleant, where the first Pb layer becomes the new surface layer of the substrate. At an undercooling of about 22 K, nucleation proceeds by merging 2D ordered structure through structural templating: the second Pb layer is epitaxial to the CSL Pb layer, the third Pb layer largely accommodates the f_r, and the fourth Pb layer is a nearly perfect crystalline plane. Further analysis indicates that the interface with the CSL has a lower interfacial energy than with a cube-to-cube orientation relationship. For the first time, we established that the CSL was an effective mechanism to accommodate the f for systems with a large positive misfits. Heterogeneous nucleation is governed not by a single mechanism (misfit dislocations in Turnbull's model), but instead by various mechanisms depending on f. This study sheds new light on the atomistic mechanism of heterogeneous nucleation.

A residual network with attention module for hyperspectral information of recognition to trace the origin of rice

In this work, a neural network framework for hyperspectral information recognition was proposed, combined with residual block and convolutional block attention module (CBAM) to enhance the detection performance of hyperspectral for tracing the rice quality. Firstly, the hyperspectral image system was used to obtain the hyperspectral information of the rice. Secondly, due to the small data set, the structure of the residual network was designed based on the characteristics of the hyperspectral information to prevent overfitting the model. Finally, the CBAM was introduced to calculate the channel and spatial attention to redistribute the weight parameter and enhance the classification performance of the model. The results showed that our (Res-CBAM) model had better classification performance than other classification methods. The classification accuracy of the rice was 96.33%. This study provided a strategy to enhance the detection performance of hyperspectral, and an intelligent technology to trace the rice quality.

A modified feature fusion method for distinguishing seed strains using hyperspectral data

Precise classification of seeds is important for agriculture. Due to the slight physical and chemical difference between different types of wheat and high correlation between bands of images, it is easy to fall into the local optimum when selecting the characteristic band of using the spectral average only. In this paper, in order to solve this problem, a new variable fusion strategy was proposed based on successive projection algorithm and the variable importance in projection algorithm to obtain a comprehensive and representative variable feature for higher classification accuracy, within spectral mean and spectral standard deviation, so the 25 feature bands obtained are classified by support vector machine, and the classification accuracy rate reached 83.3%. It indicates that the new fusion strategy can mine the effective features of hyperspectral data better to improve the accuracy of the model and it can provide a theoretical basis for the hyperspectral classification of tiny kernels.

Salivary Cortisol Determination on Smartphone-Based Differential Pulse Voltammetry System

Cortisol is commonly used as a significant biomarker of psychological or physical stress. With the accelerated pace of life, non-invasive cortisol detection at the point of care (POC) is in high demand for personal health monitoring. In this paper, an ultrasensitive immunosensor using gold nanoparticles/molybdenum disulfide/gold nanoparticles (AuNPs/MoS2/AuNPs) as transducer was explored for non-invasive salivary cortisol monitoring at POC with the miniaturized differential pulse voltammetry (DPV) system based on a smartphone. Covalent binding of cortisol antibody (CORT-Ab) onto the AuNPs/MoS2/AuNPs transducer was achieved through the self-assembled monolayer of specially designed polyethylene glycol (PEG, SH-PEG-COOH). Non-specific binding was avoided by passivating the surface with ethanolamine. The miniaturized portable DPV system was utilized for human salivary cortisol detection. A series current response of different cortisol concentrations decreased and exhibited a linear range of 0.5-200 nM, the detection limit of 0.11 nM, and high sensitivity of 30 μA M-1 with a regression coefficient of 0.9947. Cortisol was also distinguished successfully from the other substances in saliva. The recovery ratio of spiked human salivary cortisol and the variation of salivary cortisol level during one day indicated the practicability of the immunosensor based on the portable system. The results demonstrated the excellent performance of the smartphone-based immunosensor system and its great potential application for non-invasive human salivary cortisol detection at POC.

Fuzzy Evaluation Output of Taste Information for Liquor Using Electronic Tongue Based on Cloud Model

As a taste bionic system, electronic tongues can be used to derive taste information for different types of food. On this basis, we have carried forward the work by making it, in addition to the ability of accurately distinguish samples, be more expressive by speaking evaluative language like human beings. Thus, this paper demonstrates the correlation between the qualitative digital output of the taste bionic system and the fuzzy evaluation language that conform to the human perception mode. First, through principal component analysis (PCA), backward cloud generator and forward cloud generator, two-dimensional cloud droplet groups of different flavor information were established by using liquor taste data collected by electronic tongue. Second, the frequency and order of the evaluation words for different flavor of liquor were obtained by counting and analyzing the data appeared in the artificial sensory evaluation experiment. According to the frequency and order of words, the cloud droplet range corresponding to each word was calculated in the cloud drop group. Finally, the fuzzy evaluations that originated from the eight groups of liquor data with different flavor were compared with the artificial sense, and the results indicated that the model developed in this work is capable of outputting fuzzy evaluation that is consistent with human perception rather than digital output. To sum up, this method enabled the electronic tongue system to generate an output, which conforms to human's descriptive language, making food detection technology a step closer to human perception.

Evaluation of Food Fineness by the Bionic Tongue Distributed Mechanical Testing Device

In this study, to obtain a texture perception that is closer to the human sense, we designed eight bionic tongue indenters based on the law of the physiology of mandibular movements and tongue movements features, set up a bionic tongue distributed mechanical testing device, performed in vitro simulations to obtain the distributed mechanical information over the tongue surface, and preliminarily constructed a food fineness perception evaluation model. By capturing a large number of tongue movements during chewing, we analyzed and simulated four representative tongue movement states including the tiled state, sunken state, raised state, and overturned state of the tongue. By analyzing curvature parameters and the Gauss curvature of the tongue surface, we selected the regional circle of interest. With that, eight bionic tongue indenters with different curvatures over the tongue surface were designed. Together with an arrayed film pressure sensor, we set up a bionic tongue distributed mechanical testing device, which was used to do contact pressure experiments on three kinds of cookies-WZ Cookie, ZL Cookie and JSL Cookie-with different fineness texture characteristics. Based on the distributed mechanical information perceived by the surface of the bionic tongue indenter, we established a food fineness perception evaluation model by defining three indicators, including gradient, stress change rate and areal density. The correlation between the sensory assessment and model result was analyzed. The results showed that the average values of correlation coefficients among the three kinds of food with the eight bionic tongue indenters reached 0.887, 0.865, and 0.870, respectively, that is, a significant correlation was achieved. The results illustrate that the food fineness perception evaluation model is effective, and the bionic tongue distributed mechanical testing device has a good practical significance for obtaining food texture mouthfeel information.

Odor Fingerprint Analysis Using Feature Mining Method Based on Olfactory Sensory Evaluation

In this paper, we aim to use odor fingerprint analysis to identify and detect various odors. We obtained the olfactory sensory evaluation of eight different brands of Chinese liquor by a lab-developed intelligent nose. From the respective combination of the time domain and frequency domain, we extract features to reflect the samples comprehensively. However, the extracted feature combined time domain and frequency domain will bring redundant information that affects performance. Therefore, we proposed data by Principal Component Analysis (PCA) and Variable Importance Projection (VIP) to delete redundant information to construct a more precise odor fingerprint. Then, Random Forest (RF) and Probabilistic Neural Network (PNN) were built based on the above. Results showed that the VIP-based models achieved better classification performance than PCA-based models. In addition, the peak performance (92.5%) of the VIP-RF model had a higher classification rate than the VIP-PNN model (90%). In conclusion, odor fingerprint analysis using a feature mining method based on the olfactory sensory evaluation can be applied to monitor product quality in the actual process of industrialization.

Comparison of SVM, RF and ELM on an Electronic Nose for the Intelligent Evaluation of Paraffin Samples

Paraffin odor intensity is an important quality indicator when a paraffin inspection is performed. Currently, paraffin odor level assessment is mainly dependent on an artificial sensory evaluation. In this paper, we developed a paraffin odor analysis system to classify and grade four kinds of paraffin samples. The original feature set was optimized using Principal Component Analysis (PCA) and Partial Least Squares (PLS). Support Vector Machine (SVM), Random Forest (RF), and Extreme Learning Machine (ELM) were applied to three different feature data sets for classification and level assessment of paraffin. For classification, the model based on SVM, with an accuracy rate of 100%, was superior to that based on RF, with an accuracy rate of 98.33-100%, and ELM, with an accuracy rate of 98.01-100%. For level assessment, the R² related to the training set was above 0.97 and the R² related to the test set was above 0.87. Through comprehensive comparison, the generalization of the model based on ELM was superior to those based on SVM and RF. The scoring errors for the three models were 0.0016-0.3494, lower than the error of 0.5-1.0 measured by industry standard experts, meaning these methods have a higher prediction accuracy for scoring paraffin level.

Mining Feature of Data Fusion in the Classification of Beer Flavor Information Using E-Tongue and E-Nose

Multi-sensor data fusion can provide more comprehensive and more accurate analysis results. However, it also brings some redundant information, which is an important issue with respect to finding a feature-mining method for intuitive and efficient analysis. This paper demonstrates a feature-mining method based on variable accumulation to find the best expression form and variables’ behavior affecting beer flavor. First, e-tongue and e-nose were used to gather the taste and olfactory information of beer, respectively. Second, principal component analysis (PCA), genetic algorithm-partial least squares (GA-PLS), and variable importance of projection (VIP) scores were applied to select feature variables of the original fusion set. Finally, the classification models based on support vector machine (SVM), random forests (RF), and extreme learning machine (ELM) were established to evaluate the efficiency of the feature-mining method. The result shows that the feature-mining method based on variable accumulation obtains the main feature affecting beer flavor information, and the best classification performance for the SVM, RF, and ELM models with 96.67%, 94.44%, and 98.33% prediction accuracy, respectively.

Down-regulation of DAB2IP promotes colorectal cancer invasion and metastasis by translocating hnRNPK into nucleus to enhance the transcription of MMP2

DOC-2/DAB2 interacting protein (DAB2IP) is a RasGAP protein that shows a suppressive effect on cancer progression. Our previous study showed the involvement of transcription regulation of DAB2IP in metastasis of colorectal cancer (CRC). However, the molecular mechanisms of DAB2IP in regulating the progression of CRC need to be further explored. Here, we identified heterogeneous nuclear ribonucleoprotein K (hnRNPK) and matrix metalloproteinase 2 (MMP2) as vital downstream targets of DAB2IP in CRC cells by two-dimensional fluorescence difference gel electrophoresis and cDNA microassay, respectively. Mechanistically, down-regulation of DAB2IP increased the level of hnRNPK through MAPK/ERK signaling pathway. Subsequently, translocation of hnRNPK into nucleus enhanced the transcription activity of MMP2, and therefore promoted invasion and metastasis of CRC. Down-regulation of DAB2IP correlated negatively with hnRNPK and MMP2 expressions in CRC tissues. In conclusion, our study elucidates a novel mechanism of the DAB2IP/hnRNPK/MMP2 axis in the regulation of CRC invasion and metastasis, which may be a potential therapeutic target.

Robust topology optimization of three-dimensional photonic-crystal band-gap structures

We perform full 3D topology optimization (in which "every voxel" of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, including fcc (including diamond), bcc, and simple-cubic lattices. Even without imposing the constraints of any fabrication process, the resulting optimal gaps are only slightly larger than previous hand designs, suggesting that current photonic crystals are nearly optimal in this respect. However, optimization can discover new structures, e.g. a new fcc structure with the same symmetry but slightly larger gap than the well known inverse opal, which may offer new degrees of freedom to future fabrication technologies. Furthermore, our band-gap optimization is an illustration of a computational approach to 3D dispersion engineering which is applicable to many other problems in optics, based on a novel semidefinite-program formulation for nonconvex eigenvalue optimization combined with other techniques such as a simple approach to impose symmetry constraints. We also demonstrate a technique for robust topology optimization, in which some uncertainty is included in each voxel and we optimize the worst-case gap, and we show that the resulting band gaps have increased robustness to systematic fabrication errors.

Emerging applications of sperm, embryo and somatic cell cryopreservation in maintenance, relocation and rederivation of swine genetics

Advances in porcine assisted reproductive technology (ART) make it possible to use cryopreserved sperm, embryos and somatic cells in the maintenance, relocation and regeneration of swine genetics. In this review, development of key application-limiting technology is discussed in each cell type, focusing on the efficiencies, ease of storage and transportation, and minimization of pathogen transmission. Methods to regenerate swine genetics and/or models using frozen sperm, embryos and somatic cells in combination with other porcine ARTs, such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and somatic cell nuclear transplantation (SCNT), are also discussed. The applications of these ARTs utilizing cryopreserved cells will greatly increase the efficiency as well as biosecurity for maintenance, relocation and rederivation of swine genetics/models.

Electronic nose based on an optimized competition neural network

In view of the fact that there are disadvantages in that the class number must be determined in advance, the value of learning rates are hard to fix, etc., when using traditional competitive neural networks (CNNs) in electronic noses (E-noses), an optimized CNN method was presented. The optimized CNN was established on the basis of the optimum class number of samples according to the changes of the Davies and Bouldin (DB) value and it could increase, divide, or delete neurons in order to adjust the number of neurons automatically. Moreover, the learning rate changes according to the variety of training times of each sample. The traditional CNN and the optimized CNN were applied to five kinds of sorted vinegars with an E-nose. The results showed that optimized network structures could adjust the number of clusters dynamically and resulted in good classifications.

Design of photonic crystals with multiple and combined band gaps

We present and use an algorithm based on convex conic optimization to design two-dimensional photonic crystals with large absolute band gaps. Among several illustrations we show that it is possible to design photonic crystals which exhibit multiple absolute band gaps for the combined transverse electric and magnetic modes. The optimized crystals show complicated patterns which are far different from existing photonic crystal designs. We employ subspace approximation and mesh adaptivity to enhance computational efficiency. For some examples involving two band gaps, we demonstrate the tradeoff frontier between two different absolute band gaps.

Birth of piglets from in vitro-produced, zona-intact porcine embryos vitrified in a closed system

As the importance of swine models in biomedical research increases, it is essential to develop low-cost, high-throughput systems to cryopreserve swine germplasm for maintenance of these models. However, porcine embryos are exceedingly sensitive to low temperature and successful cryopreservation is generally limited to the use of vitrification in open systems that allow direct contact of the embryos with liquid nitrogen (LN(2)). This creates a high risk of pathogen transmission. Therefore, cryopreservation of porcine embryos in a "closed" system is of very high importance. In this study, in vitro-produced (IVP) porcine embryos were used to investigate cryosurvival and developmental potential of embryos cryopreserved in a closed system. Optimal centrifugal forces to completely disassociate intracellular lipids from blastomeres were investigated using Day-4 embryos. Cryosurvival of delipidated embryos was investigated by vitrifying the embryos immediately after centrifugation, or after development to blastocysts. In this study, centrifugation for 30 min at 13,000 g was adequate to completely delipidate the embryos; furthermore, these embryos were able to survive cryopreservation at a rate comparable to those centrifuged for only 12 min. When delipidated embryos were vitrified at the blastocyst stage, there was no difference in survival between embryos vitrified using OPS and 0.25 mL straws. Some embryos vitrified by each method developed to term. These experiments demonstrated that porcine embryos can be cryopreserved in a closed system after externalizing their intracellular lipids. This has important implications for banking swine models of human health and disease.

305 INCREASED MONOSPERMIC PENETRATION OF PORCINE OOCYTES USING A VISCOUS IN VITRO FERTILIZATION SYSTEM

The high incidence of polyspermy remains a major problem in porcine IVF systems. The high number of sperm bound to the oocyte is one of the major causes for pathological polyploidy (Funahashi 2003 Reprod. Fertil. Dev. 15, 167–177). In this experiment, we tested the hypothesis that limiting the number of competent sperm able to participate in fertilization during IVF will result in a reduction in polyspermic penetration. Combinations of various sperm (3 levels) and Percoll concentrations (3 levels) were used in a modified Tris-buffered medium (mTBM) with 3% polyvinylpyrrolidone supplementation to find the optimal combination that could result in a significant reduction in polyspermy rate compared with that resulting from the current porcine IVF system (Abeydeera and Day 1997 Theriogenology 48, 537–544). In vitro-matured gilt oocytes (n = 844) were randomly allocated into 1 of 10 treatment groups in groups of 30. Motile sperm were selected from frozen–thawed samples by density gradient centrifugation using a discontinuous Percoll gradient consisting of 3 mL of 54% Percoll in PBS on top of 1 mL of 72% Percoll in a 15-mL conical tube at 600g for 15 min. After centrifugation, the supernatant was removed as much as possible without disturbing the sperm pellet. Sperm stock solutions were made in a manner that resulted in the desired final concentration of sperm when 5 µL of the sperm solution were added to 95 µL of fertilization medium. During IVF, the sperm stock solutions were placed at one side of an IVF droplet so that most sperm were trapped inside the viscous Percoll solution and only a limited number of sperm, with high progressive motility, were capable of fertilizing the oocytes. A group of oocytes fertilized using our standard IVF protocol with a sperm concentration of 5 × 105 sperm mL−1 in mTBM served as a control. Pronuclear formation after 12 h of fertilization was used to assess sperm penetration. The data from 3 replicates were analyzed by standard ANOVA procedures using the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA). The treatment group of 5 × 105 sperm mL−1 + 10% Percoll resulted in a significantly higher monospermy rate than the control or the treatment group of 1 × 106 sperm mL−1 + 30% Percoll (Table 1; P < 0.05). These data support the hypothesis that the polyspermy rate in a porcine IVF system can be reduced by limiting the number of competent sperm fertilizing the oocytes. Table 1.Monospermy rates in a viscous IVF system (mean ± SEM%) This project was supported by NIH U42 RR 018877.

169 FORSKOLIN INDUCED INCREASE IN LIPOLYTIC ACTIVITY I PORCINE EMBRYOS PRODUCED IN VITRO

The sensitivity of porcine embryos to cryopreservation is largely due to their high level of intracellular lipid content (Polge and Willadsen 1978 Cryobiology 15, 370-373). Delipation through centrifugation and micromanipulation resulted in a significant proportion of porcine embryos produced in vivo being able to survive cryopreservation and produce live births (Nagashima et al. 1995 Nature 374, 416). However, due to the intense resources needed for delipation via micromanipulation, this approach has limited practical value. In this experiment, we tested the hypothesis that delipation can be achieved through chemical stimulation of intracellular lipolysis in porcine embryos produced in vitro. Day 6 porcine blastocysts cultured in the presence of 10 �M forskolin, a lipolytic agent (Ho and Shi 1982 Biochem. Biophys. Res. Commun. 107, 157-164), in a group of 101-202 blastocysts per 50 �L of NCSU-23 + 4 mg/mL BSA (Sigma-Aldrich, St. Louis, MO, USA) yielded approximately 125 000-250 000 cells/mL (Zalatan et al. 2001 Endocrinology 142, 3783-3790). Blastocysts cultured in 50 �L NCSU-23 + 4 mg/mL BSA without the supplementation of forskolin served as control. Samples (12 �L) of the media were taken from culture at 0, 3, and 6 h and frozen at -20�C for lipolytic assay. Because the major content of intracellular lipids in porcine embryos is triacylglycerol and the hydrolysis of triacylglycerol results in the production of fatty acid and glycerol, therefore, the lipolytic activity in porcine blastocysts was measured by detection of glycerol concentration in the culture media. A commercially available Free Glycerol Regent (Sigma) was used with modifications. This kit only measures free glycerol released into the media as a result of endogenous lipase activity because the kit itself doesn't contain lipase. Ten �L of sample medium was mixed with 80 �L of Free Glycerol Regent and incubated in a 37�C water bath for 5 min. The resulting samples were read using a Cary 50 UV Spectrophotometer (Varian, Inc., Palo Alto, CA, USA). The actual concentration of glycerol in the culture medium was calculated using the glycerol standard curve. The glycerol concentration at 0 h was regarded as 0 for both the treatment group and the control group. The glycerol concentrations at other time points were calculated accordingly. The measurement was conducted four times for the treatment group and three times for the control group. The data were analyzed using a Student's t-test. Glycerol concentrations in the treatment group at 3 h and 6 h were 5.99 � 1.74 (mean � SEM) �M, and 10.49 � 0.81 �M, respectively, and both values were significantly different from their counterparts in the control group, which were 0.95 � 0.62 �M and 4.43 � 1.31 �M, respectively. These results indicate that the hydrolysis of intracellular lipids in porcine embryos can be stimulated by lipolytic agents and result in the partial reduction of the intracellular lipid content. This approach may be used for designing a better protocol for the cryopreservation of porcine embryos produced in vitro. This project was supported by a grant from the National Institutes of Health (U42 RR 018877).

155 QUALITY OF PORCINE EMBRYO PRODUCED IN TWO EMBRYO CULTURE MEDIA AS ASSESSED BY TOTAL CELL NUMBER AND TIME COURSE OF BLASTOCYST HATCHING

The ability to produce porcine embryos of good quality will have a significant impact on a number of porcine assisted reproductive technologies, such as cloning, intracytoplasmic sperm injection, and embryo cryopreservation. However, porcine embryos resulting from current serum-free embryo culture systems differ significantly both structurally and functionally from those derived in vivo (Wang et al. 1999 Mol. Reprod. Dev. 53, 99-107). In this experiment, the quality of porcine embryos produced by North Carolina State University (NCSU)-23 medium (Petters and Wells 1993 J. Reprod. Fertil. Suppl. 1993, 48, 61-73) and porcine zygote medium (PZM)-1 (Yoshioka et al. 2002 Biol. Reprod. 66, 112-119) were compared by assessing the total cell number and the time course of in vitro blastocyst hatching. Porcine embryos were produced by in vitro maturation and fertilization using serum-free systems. After fertilization, presumptive zygotes were randomly allocated to either PZM-1 or NCSU-23 for subsequent development. On Day 4 of culture, the embryo culture media were supplemented with 10% fetal bovine serum (FBS). Day 6 blastocysts from each group were counted and the blastocysts were subsequently fixed in 4% formalin for counting the total cell number. The cell number in each embryo was determined by counting the nuclei after staining with bisbenzimide (Hoechst 33342). To assess the hatching ability of blastocysts, Day 6 blastocysts were cultured until Day 9 and hatched blastocysts were counted daily. Day 6 blastocyst rates (ratio of blastocysts to oocytes) and total cell number count were replicated three times. The time course of blastocyst hatching experiment was repeated four times. The data were analyzed using a chi-square test, Fisher's exact test, or Student's t-test. The blastocyst rate from culture in PZM-3 was 19.4 � 0.96% (mean � SEM), which was similar to that (16.7 � 3.2%) resulting from culture in NCSU-23 (P > 0.05). However, the total cell number in Day 6 blastocysts cultured in PZM-3 was significantly higher than for blastocysts cultured in NCSU-23 (57 � 3.1 vs. 46 � 1.7; P < 0.01). The total hatching rates (ratio of hatched blastocysts to total blastocysts) by Day 9 were similar between the two culture systems (50.1 � 9.1% vs. 50.7 � 4.1%; P > 0.05). However, on Day 6, 2.1% of blastocysts from PZM-3 culture hatched whereas no blastocysts from NCSU-23 culture hatched. The cumulative hatching rates from PZM-3 culture on Day 7 were significantly higher than those from NCSU-23 culture (15.1 � 3.8% vs. 2.6 � 1.1%; P < 0.01). In conclusion, these data suggest that blastocysts produced in PZM-3 medium have better quality than blastocysts produced in the NCSU-23 culture system as assessed by the total cell number and the time course of blastocyst hatching. This project was supported by a grant from the National Institutes of Health (U42 RR 018877).

110OSMOTIC STRESS ON THE CELLULAR ACTIN FILAMENT ORGANIZATION OF IN VITRO PRODUCED PORCINE EMBRYOS

Disruption of the actin cytoskeleton is one of the leading causes in low survival of pig embryos after cryopreservation (Dobrinsky et al., 2000 Biol. Reprod. 62, 564–570). In this study, the effect of osmotic stress on cellular actin filament organization in porcine embryos produced in vitro was studied. Excellent quality Day 6 (fertilization=Day 0) porcine blastocysts were randomly exposed to 6 different anisosmotic sucrose solutions (75, 150, 210, 600, 1200, 2400mOsm) for 10min. Embryos were then returned to embryo culture medium (NCSU-23) after washing with NCSU-23, and cultured under 38.5°C, 5% CO2 in air with maximal humidity for them to recover. Blastocysts cultured in NCSU-23 medium (280mOsm) served as a control for embryos with intact actin filament organization. Blastocysts treated with 7.5μgmL−1 cytochalasin-b for 60min served as a control for embryos with F-actin depolymerization. Eighteen hours post-anisosmotic treatments, all blastoysts were fixed in 3.7% paraformaldehyde in PBS for 60min and stored in PBS with 0.1% Triton X-100 and 0.2% sodium azide at 4°C. Staining of actin filaments was performed according to procedures described earlier (Wang et al., 1999 Biol. Reprod. 60, 1020–1028). Embryos were blocked in PBS with 20mgmL−1 BSA and 150mM glycine for 30min. After being washed in PBS with 0.1% Tween 20 for 60min, embryos were stained with 10UmL−1 Alexa Fluor 488 phalloidin in PBS with 0.1% Tween 20 at 38.5°C for 60min, and then washed twice in PBS with 0.1% Tween 20 for 60min each. The status of actin filaments in embryonic cells was examined by confocal microscopy. Integrity of cellular actin filaments was classified as either intact or disrupted according to the distribution within embryonic cells. Blastocysts were then classified according to the status of actin filaments in embryonic cells. Data were analyzed using logistic regression. Results from 7 replicates are displayed in Table 1. There was a significant relationship between osmotic treatment levels and the probability of blastocysts with disrupted cellular actin filaments (P&lt;0.0001). These data support the hypothesis that porcine embryos are very sensitive to osmotic changes. Ongoing experiments will assess the extent of actin disruption required to significantly reduce developmental competence of pig blastocysts. This study was supported by Monsanto Company. Table 1 Cellular actin filament integrity of in vitro produced porcine blastocysts after being treated with sucrose solutions with different osmolalities (mOsm)

Detection of DNA damage in bovine metaphase II oocytes resulting from cryopreservation

Developmental competence of mammalian oocytes is compromised by currently available oocyte cryopreservation protocols. Experiments were designed to examine the effect of three cryopreservation protocols on the integrity of bovine oocyte DNA. In vitro matured bovine oocytes were cryopreserved either by slow cooling, vitrification in 0.25 ml straws, or in open pulled straws. After thawing/warming, recovered oocytes were immediately subjected to morphological evaluation. Morphologically intact oocytes underwent comet assay to detect cryoinjury at DNA level. All cryopreservation protocols resulted in significant morphological damage as well as DNA damage compared to unfrozen control. Among the morphologically intact oocytes, there was no difference among protocols in the number of oocytes displaying DNA damage. However, oocytes that had been cryopreserved by slow cooling or by vitrification in open pulled straws exhibited more damage than those vitrified in 0.25 ml straws in the extent of DNA damage. If we combine the number of oocytes with morphological damage and oocytes with DNA damage, oocytes cooled by slow cooling resulted in the most damage. This experiment demonstrated that oocyte DNA is a target of cryoinjury and different protocols result in different degrees of damage.