bluuebunny/crossref_metadata_2025 huggingface dataset:
269 EXPRESSION PATTERN OF STRESS MARKER GENES IN BOVINE OOCYTES MATURED IN VITRO IN MEDIA WITH DIFFERENT HORMONE COMPOSITION
Authors: Cánepa M. J. , Mutto A. A.
Published: August 2011

Evaluation and prediction of oocyte quality are 2 critical issues in assisted reproductive technologies. The lack of reliable and objective predictors of oocyte developmental competence, and subsequent embryonic development, negatively affects the efficiency of assisted reproductive technologies. The aim of this work was to study the effect of different bovine oocyte maturation protocols on the relative transcript abundance from genes involved in cellular stress (70-kDa heat shock proteins), endoplasmic reticulum (ER) stress (Bip: immunoglobulin heavy chain binding protein and proteasome subunit β-5 protease), and apoptosis (Bax and Caspase-3). Oocytes were matured in 5 different media that varied in the composition of hormones and cysteamine: 1) porcine FSH (Folltropin®, Bioniche Animal Health, Belleville, Ontario, Canada) and cysteamine, 2) epidermal growth factor (EGF), 3) EGF and cysteamine, 4) recombinant human FSH (rhFSH), and 5) rhFSH and cysteamine. Three groups of 10 matured oocytes in each of the 5 different maturation media were analysed by real-time RT-PCR. The results were normalized to the expression of the endogenous control (glyceraldehyde-3-phosphate dehydrogenase). Messenger RNA abundance data were analysed using the InfoStat software (Universidad Nacional de Córdoba, Argentina). One-way ANOVA, followed by Tukey multiple comparison test, was used for the analysis of differences in mRNA abundance. The abundance of the β-5 subunit of the proteasome mRNA increased 70% (P < 0.05) in oocytes matured in medium supplemented with porcine FSH and cysteamine compared with that in the oocytes matured in the other maturation media supplemented with rhFSH and EGF with or without cysteamine. The expression of the ER chaperone, Bip, increased 120% (P < 0.05) in oocytes that were matured in the same medium, compared with that in those matured in medium supplemented with rhFSH and cysteamine. The results suggest that maturation of oocytes in medium supplemented with porcine FSH and cysteamine induced ER stress, which is reflected by the increased abundance of the chaperone Bip and β-5 protease. Given that the abundance of the cytoplasmic chaperone Hsp70 was not altered in any of the treatments, there was no evidence of widespread cellular stress. However, it seemed that these conditions were not stressful enough to induce apoptosis because Bax and Caspase-3 markers were not modified. This study could complement morphological analysis to help develop an effective and accurate technique to diagnose oocyte quality during assisted reproductive technologies.
273 CONSEQUENCE OF HIGH NONESTERIFIED FATTY ACID CONCENTRATIONS DURING BOVINE OOCYTE IN VITRO MATURATION ON mRNA TRANSCRIPT ABUNDANCE OF BLASTOCYSTS
Authors: Van Hoeck V. , Bermejo-Álvarez P. , Rizos D. , Gutierrez-Adan A. , Andries S. , Bols P. E. J. , Leroy J. L. M. R.
Published: August 2011

In recent years, high nonesterified fatty acid (NEFA) concentrations have been intensively discussed as an important metabolic cue linking negative energy balance in high yielding dairy cows early postpartum to disappointing fertility. Previous research has shown that high NEFA concentrations during in vitro oocyte maturation not only induce significant negative effects on the developmental capacity of oocytes but also reduce the quality and viability of the subsequent embryos that do survive until 7 days post-insemination. Because NEFA are known to regulate gene expression, the objective of this study was to investigate the effect of NEFA exposure during bovine in vitro oocyte maturation on the relative transcript abundance in the resultant day 7 blastocysts. This study focused on key genes related to embryonic quality, apoptosis, adaptation to stress, metabolism, DNA methylation, growth factors, and fatty acid synthesis. During a serum-free maturation period of 24 h, bovine cumulus–oocyte complexes were exposed to maturation medium (0.75% BSA) supplemented with 1) physiological NEFA concentrations (control; 150 μM of total NEFA, i.e. oleic, stearic, and palmitic acid), 2) elevated stearic acid concentrations (HSA; 75 μM of stearic acid), and 3) elevated NEFA concentrations (HCOMBI; 425 μM of total NEFA). Following IVF using semen from a bull of proven fertility, zygotes were cultured in SOF (+5% of FCS) medium for 7 days. Studied mRNA transcripts were quantified by real-time quantitative RT-PCR. Experiments were conducted to determine levels of each transcript relative to H2AZ in every sample. Relative mRNA abundance differences among groups were analysed by one-way ANOVA. Significant increases (P < 0.05) in relative mRNA abundance of the HCOMBI embryos were found for genes related to DNA methylation (DNMT3A), growth factors (IGF2R), glucose transport (SLC2A1), and fatty acid synthesis (ACSL1 and ACACA) compared with control embryos. Furthermore, HCOMBI embryos revealed a significantly higher expression (P < 0.05) of IGF2R and ACSL1 than did HSA embryos. The level of transcripts of genes related to mitochondrial biogenesis (TFAM) and the adaptation to stress (MNSOD) also tended to be increased in HCOMBI embryos compared with control embryos (P = 0.09 and P = 0.10, respectively). In conclusion, there is ample evidence that embryos originating from oocytes matured under negative energy balance conditions show aberrant transcriptional activities. These results might improve our current understanding of the possible mechanisms through which NEFA exposure during oocyte maturation affects the developmental capacity, quality, and viability of the resultant embryo.
297 DERIVATION AND CHARACTERIZATION OF THE TRANSGENIC SOMATIC CELL NUCLEAR TRANSFER-DERIVED BOVINE EMBRYONIC STEM CELLS
Authors: Jeong S. H. , Kim H. S. , Lee H. , Uh K. J. , Hyun S. H. , Kim Y. W. , Shin T. , Jung E.-B. , Hwang W. S.
Published: August 2011

Bovine transgenic embryonic stem (ES) cells have not been reported yet because it seems that the derivation methods and the culture conditions for the inner cell mass are neither consistent nor optimized. Isolation of inner cell mass and primary culture of ES colonies is a critical step toward the establishment of authentic bovine ES cell lines. Herein, we reconstructed somatic cell nuclear transferred (SCNT) bovine blastocysts carrying a vector expressing the human INF-α gene, and isolated inner cell masses to derive transgenic bovine embryonic stem cells. In addition, we added 2 inhibitors, inhibition (2i system) of the mitogen-activated protein kinase (Erk1/2) cascade, PD0325901(3 Î1/4M), and of glycogen synthase kinase 3, CHIR99021 (1 Î1/4M), in the inner cell mass primary culture to check reliability of the 2i system for bovine ES culture. The 2 inhibitors made the morphology of colonies more intact, and primary colonies were better maintained in early passages. However, there were no significant effects on the attachment rate and maintenance in late passages (percent of percent over 3 passages: 2i system, 21/38 (55.3%); control, 22/42 (33.3%); P < 0.05). Inner cell masses were isolated mechanically and subcultured by an enzymatic in primary inner cell mass culture. Massive growth of trophoblast cells appears to inhibit inner cell mass growth, so hatching and hatched blastocysts were cut with a needle to remove trophoblast cells. Poor quality blastocysts were attached by the whole seeding method, and the margin trophoblast cells were consecutively removed in early passages. Established bovine ES cells express alkaline phosphatase, Oct-4, SSEA1, SSEA4, Tra-1–60, and Tra-1–81. We confirmed pluripotent gene expression of bovine ES like cells; Oct-4, SSEA1, and Rex 1 were positive, but trophoblast marker CDX2 was negative. This study shows that the 2i system is a reasonable method for use during inner cell mass culture in early passages. We established 6 transgenic nuclear transfer bovine ES cell lines with the 2i system and 4 in vitro fertilized bovine ES cell lines (all were over 10 passages).
315 MELATONIN EFFECTS ON THE PROLIFERATION AND DIFFERENTIATION OF MOUSE EMBRYONIC STEM CELLS
Authors: Yoo Y.-M. , Jeung E.-B.
Published: August 2011

Mouse embryonic stem (ES) cells constitute a versatile biological system that can facilitate major advances in the fields of cell and developmental biology. Several studies have been performed to determine whether melatonin can affect ex vivo and in vitro proliferation and differentiation of stem cells (mesenchymal and neural stem cells derived human, rats, and mice), but its effect on ES cells is largely unknown. Thus, we further examined in this study the effects of melatonin at biological or pharmacological concentrations (100 or 200 μM) on the proliferation and differentiation of ES cells (ES-E14TG2a cells) using an in vitro culture system (n = 3) by Western blot analysis and real-time PCR. We found that melatonin at 100 and 200 μM resulted in cellular proliferation and phosphorylation of ERK and Akt, respectively. Melatonin treatment also increased Bcl-2 expression and suppressed Bax gene expression and increased phosphorylation of GSK α/β. The transcription factor Oct-4, which contains the POU (N-terminal to homeobox) domain, and the transcription factor Sox2, the zinc finger transcription factor Zfp206, and the zinc finger gene REX-1 (Znf42), which contain the high mobility group domain, are all important for cellular pluripotency and preimplantation development. In this study, melatonin (100 μM) treatment induced Oct-4 and REX-1 expression at day 1 but not at days 2 and 3. In addition, Sox2 and Zfp206 expressions were not altered following melatonin treatment. Taken together, these results suggest that melatonin may affect Akt phosphorylation and stem cell proliferation at biological or pharmacological concentrations.
35 EFFECTIVENESS OF MICROWELL-BASED IN VITRO CULTURE SYSTEMS FOR BOVINEZONA-FREE CLONED EMBRYOS
Authors: Feltrin C. , Machado M. , Queiroz L. M. V. , Peixer M. A. S. , Malard P. F. , Santana G. M. , Bertolini M. , Wheeler M. , Rodrigues J. L.
Published: August 2011

In vitro embryo production by handmade cloning (HMC) usually requires individual embryo culture, because zona-free embryos cannot be grouped in standard in vitro culture (IVC) protocols. The aim of this study was to evaluate the developmental potential of bovine embryos produced by HMC (Ribeiro et al. 2009 Cloning Stem Cells 11, 377–386) after in vitro culture (IVC) in 3 microwell (WOW) systems. After in vitro maturation, oocytes were denuded and incubated in demecolcine (Ibáñez et al. 2003 Biol. Reprod. 68, 1249–1258), followed by zona pellucida removal, oocyte bisection, embryo reconstruction, electrofusion, and chemical activation. Cloned embryos were allocated to 1 of 3 IVC groups: cWOW: conventional microwells (250 μm, round; Vajta et al. 2000 Mol. Reprod. Dev. 55, 256–264); mWOW: modified microwells (130 μm, conical; Feltrin et al. 2006 Reprod. Fert. Dev. 18, 126); and WOW-PDMS: microwells in polydimethylsiloxane chips (170 μm, cylindrical with microchannels); IVF embryos were used as controls (Bertolini et al. 2004 Reproduction 128, 341–354). Cleavage (Day 2), blastocyst (Day 7), and pregnancy (Day 30) rates were analysed by the chi-square test, for P < 0.05. Results are shown in Table 1. Cleavage rates were similar between groups, but development to the blastocyst stage was higher in IVF controls than cloned embryo groups. Among cloned embryo groups, blastocyst rate was higher in the mWOW group than the conventional and the PMDS-based microchannels. Nevertheless, in vivo development to Day 30 of pregnancy was not different between cloned groups. Our results for in vitro embryo development indicated that the mWOW provided more suitable conditions for embryo development to the blastocyst stage when compared with cWOW or even WOW-PDMS. Among some possible reasons include the physical advantage of a smaller microwell that may better mimic the constraining effect of the zona pellucida on the developing embryo. That may also provide greater blastomere stability, favouring the aggregation state during the first rounds of cleavages, also aiding compaction and subsequent cavitation. The narrower microwell system appeared to have promoted better in vitro development than the conventional and the DMPS-based microwell systems, with no impact on subsequent in vivo development. However, the IVC in the WOW-PDMS system supported reasonable rates of development, in accordance with the current literature.

Table 1.In vitro development of bovine IVF and cloned embryos produced after the in vitro culture in distinct IVC systems
48 DEVELOPMENTAL COMPETENCE OF CLONED OR PARTHENOGENETICALLY ACTIVATED PORCINE EMBRYOS: EFFECT OF DIAMETER OF PREPUBERTAL GILT OOCYTES
Authors: Li J. , Adamsen J. , Li R. , Pedersen H. , Liu Y. , Purup S. , Vajta G. , Callesen H.
Published: August 2011

One of the primary factors influencing the developmental ability of cloned embryos is the oocyte′s diameter (Hirao et al. 1994 J. Reprod. Fertil. 100, 333–339). However, the oocyte donor's age (i.e. its sexual maturity) is also important to consider, because a high proportion of immature oocytes can be expected (Ikeda and Takahashi 2003 Reprod. Fertil. Dev. 15, 215–221). The present study was to investigate the effect of diameter of oocytes collected from prepubertal gilts weighing 100 to 120 kg on the developmental ability of cloned and parthenogenetically activated (PA) embryos. Cumulus–oocyte complexes collected from ovaries of prepubertal gilts were in vitro matured for 42 to 44 h as described for sow oocytes (Li et al. 2008 Theriog 70, 800–808). After removal of the cumulus cells, the matured oocytes were sorted into 2 groups based on visual inspection: large (L) and small (S) oocytes, whereas non-sorted oocytes were used as control (C). In addition, 1 batch from each of the 3 groups of oocytes had their mean size measured. Subsequently, all 3 groups were used for handmade cloning (HMC; Li et al. 2009 Reprod. Domest. Anim. 44, 122–127) or parthenogenetic activation (PA; Kragh et al. 2005 Theriogenology 64, 1536–1545). Then a chemical activation with 5 μg mL–1 cytochalasin B and 10 μg mL–1 cycloheximide in PZM-3 medium was applied for 4 h on both HMC and PA embryos. Finally, the activated embryos were washed and cultured in PZM-3 medium using the WOW system. The embryo development was evaluated by cleavage rate (Day 2), blastocyst rate (Day 6), and total cell number in blastocysts. Data were analysed by ANOVA with single factor in Excel (Microsoft Excel 2007, Redmond, WA, USA). The results showed (Table 1) that by simple visual observation, oocytes could be easily sorted into the following groups: L group (mean diameter 110 μm, from 105 to 116 μm), S group (mean diameter 101 μm, from 93 to 106 μm) and C group (mean diameter 107 μm, from 93 to 116 μm). Cleavage rates and total cell number were similar in the 3 groups. However, the blastocyst rate in L group either for HMC or PA was higher than S group. The data confirm that prepubertal gilt oocytes are useful for cloning and PA, but developmental rates can be increased by selection of large oocytes by simple visual observation.

Table 1.Data analysis results
64 MACROGLOSSIA IN CLONED PIGLETS IS ASSOCIATED WITH HYPOMETHYLATION AT THE KCNQ-OT1 CpG ISLAND
Authors: Li C. , O'Gorman C. , Prather R. S. , Green J. A. , Wells K. D.
Published: August 2011

Beckwith-Wiedeman Syndrome (BWS) is a loss of imprinting (LOI) condition that is associated with macroglossia, midline abdominal defects, and neonatal gigantism among other symptoms. These symptoms have also been seen in animals produced by SCNT. A common feature of BWS is the loss of methylation at the KCNQ-OT1 differentially methylated region. We hypothesised that this locus would show a similar LOI in cloned piglets that display macroglossia. DNA sequence for the porcine KCNQ-OT1 region was assembled in silico from public genome sequencing data. A CpG island was noted as being similarly located in the swine sequence as one which has been described for the human differentially differentiated region. Primers were designed to amplify a portion of this region from bisulfite converted genomic DNA. The amplimer spanned 32 CpG sites. To confirm imprinting status of KCNQ-OT1 in swine, a non-cloned pig was evaluated as to the methylation status across this region using DNA isolated from muscle (M) and the proportion hypermethylated was evaluated by chi-square tests. As seen in humans, this region was hypermethylated in approximately half (12 of 24, P = 1) of the cloned, sequenced amplimers. This observation is consistent with a parent of origin imprint at this locus. Next, 2 cloned piglets that appeared normal were assessed for methylation at KCNQ-OT1. M DNA from each of these animals was consistent with normal methylation at this locus, (7 of 16 and 8 of 18 cloned, sequenced amplimers, P > 0.40). Next, M DNA was isolated from 2 cloned litter mates where 1 piglet presented with macroglossia and the other did not. The non-presenting piglet’s M DNA was methylated in approximately half of the cloned sequenced amplimers (9 of 17, P = 0.67) whereas the macroglossia piglet M DNA was devoid of the methylated allele (0 of 14, P < 0.001). An additional pair of macroglossia presenting and non-presenting cloned littermates was identified. In this pair, the non-presenting piglet showed a normal distribution of methylation at this allele (8 of 19, P = 0.77) and the macroglossia piglet deviated somewhat from normal (6 of 20, P < 0.05). These 2 case studies are consistent with the conclusion that the appearance of macroglossia in cloned pigs may be associated with hypomethylation at KCNQ-OT1 and may model BSW. However, additional abnormal pigs will need to be assessed to completely characterise the LOI in cloned piglets.
7 ESTRUS LENGTH AND INTENSITY IN BOS TAURUS (HOLSTEIN) v. BOS INDICUS (NELORE) NONLACTATING COWS
Authors: Bastos M. R. , Meschiatti M. A. P. , Surjus R. S. , Prata A. B. , Lemes A. P. , Guardieiro M. M. , Santos F. A. P. , Sartori R.
Published: August 2011

The aim of this study was to compare the length and intensity of oestrus in nonlactating Bos taurus (Holstein; n = 11) v. nonlactating Bos indicus (Nelore; n = 13) cows. The cows were kept in a single pen to allow interaction between them and were daily fed a maintenance diet according to the NRC (2000), containing 42.8% sugarcane bagasse, 45.7% corn, 3.2% soybean meal, 1.2% urea, 5.7% molasses, and 1.4% mineral salt, totaling 71% dry matter (DM) in the diet. The intake of DM per kg of body weight (BW) was 1.45%. Body condition score and BW were 3.5 ± 0.1 and 3.0 ± 0.2 (range 1 to 5), and 549.5 ± 14.3 and 625.5 ± 20.5 kg for Nelore and Holstein cows, respectively. All females had the emergence of follicular wave synchronized with an intravaginal progesterone device (Sincrogest, Ourofino Agronegócio, São Paulo, Brazil), 2 mg of oestradiol benzoate (Sincrodiol, Ourofino; IM) and 0.150 mg PGF2α (Sincrocio, Ourofino; IM). Ten days after initiation of the protocol, the intravaginal device was removed and another treatment with 0.150 mg PGF2α was given. Thereafter, cows were evaluated for oestrus by continuous visual observation 24 h a day for 5 days. The number of the cow that was mounting and the number of the cow that was standing was recorded for each event, as well as the time of the event. To confirm ovulation, ultrasound examination was performed between 5 and 7 days after oestrus detection. Data were analysed by Student’s t-test and Fisher’s exact test or Chi-square and data are presented as mean ± SE or percentage. Ten of 13 (76.9%) and 11 of 11 (100%) Nelore and Holstein cows, respectively, were detected in standing oestrus and ovulated (P > 0.10). On average, Holstein cows tended to start oestrus earlier than Nelore cows after device removal (40.4 ± 2.9 v. 47.7 ± 2.8 h; P = 0.09). There was no difference in intensity and duration of oestrus between Bos taurus and Bos indicus cows. Oestrus length was 14.7 ± 1.0 h (range 8.3 to 19.0 h) in Holstein cows and 12.4 ± 0.8 h (range 8.6 to 17.1 h) in Nelore cows (P > 0.10). Moreover, the average number of times that cows accepted mounts was 32.2 ± 6.1 and 36.3 ± 5.3 for Holstein and Nelore cows, respectively (P > 0.10). Only 9.1% of the mounts accepted by Nelore cows were performed by Holstein cows and only 3.8% of the mounts accepted by Holstein cows were done by Nelore cows (P < 0.05). We concluded that Bos taurus and Bos indicus cows managed under similar environment and nutritional conditions exhibit oestrus with the same intensity and duration. However, there was very little interaction during oestrus between Nelore and Holstein cows, showing a breed segregation pattern.

This work was financially supported by CNPq, FAPESP, and Ourofino Agronegócio of Brazil.
9 EVALUATION OF FERTILITY TRAITS OF HOLSTEIN CATTLE IN ARGENTINA
Authors: Di Croce F. A. , Saxton A. M. , Casanova D. , Schrick F. N.
Published: August 2011

Impaired fertility is the primary reason for culling in the United States (26.5% of all disposals) and fertility rates have steadily declined during the past 30 years. The objectives of this study were 1) estimate genetic parameters and evaluate genetic correlations for fertility traits based on data from milk recording programs, and 2) evaluate genetic fertility trends in Holstein cattle in Argentina. Data representing 3 282 843 lactations and 1 622 088 animals (cows and bulls from 1936 to 2007) were used for the analysis and obtained from official records maintained by the Argentinean Holstein Association (ACHA). Lactations were standardized to 305 DIM for milk, protein, and fat. Days open (DO), calving interval (CI), age to first calving (AFC), and daughter pregnancy rate (DPR) were selected for genetic parameter estimation. Daughter pregnancy rate was calculated as described by (Kuhn et al. 2004 J. Dairy Sci. 87, 2277–2284). Animal models by lactation for each fertility trait included contemporary group (dairy herd and calving year), calving month, animal effect, milk production as a covariate, and error term. Multiple-trait derivative-free restricted maximum likelihood (MTDFREML) was used to estimate covariance components. Solutions for fixed effects, breeding values, and sampling variances (accuracies) were obtained for each trait. The fertility index ($F = –0.28 × AFC ± 4.9 × CI) was calculated using the economic rates as reported by (Gonzalez-Recio et al. 2004 J. Dairy Sci. 87, 3053–3061). First lactation/parities were utilised for estimating correlations among BLUPs for DO, CI, DPR, AFC, and $F. In general, moderate and high genetic correlations were observed (from 0.238 to 0.999; P < 0.001). Days open and calving interval showed high negative associations with DPR (–0.999, –0.648) and $F (–0.612, Q0.981). Results from the correlation analysis suggest that CI and $F are qualified indicators of fertility in lactating dairy Holstein and relate well with all the other traits. The index, $F, benefits by including AFC as a measure of initial reproductive efficiency followed by the inclusion of CI which measures success of inseminations. Genetic trend for AFC showed a decrease of 2.76 days per year between 1970 and 2000 for sires. Similarly, trends for CI resulted in decreases of 0.45 days per year between 1970 and 2000 for sires. During the same period, DPR increased by 0.02 percent per year in sires. Using current dollars values, $F increased 2.99 dollars per year for sires. Results indicate progress in the genetic trend for fertility traits in the Holstein population of Argentina, with higher improvement in sires compared with dams. Trends visually showed faster improvement after 1980, possibly due to extensive importation of US and Canadian bulls and semen (72% of bulls born after 1986) and selection for productive life introduced in 1993.

Supported by Asociacion Criadores de Holando Argentino (ACHA).
92 EFFECT OF LOW-DENSITY LIPOPROTEIN ON THE QUALITY OF CRYOPRESERVED RAM SEMEN
Authors: Snoeck P. P. N. , Silva M. C. , Moura L. C. O. , Neves M. M. , Henry M.
Published: August 2011

Egg yolk is the most widely used cryoprotectant in the composition of extenders for cryopreservation of mammalian spermatozoa; yet, efforts have been made to find ways to substitute it due to the possibility of transporting pathogenic microorganisms, the lack of standardization, and the presence of substances that inhibit metabolic exchanges or decrease the motility of sperm. The protective effect of egg yolk was attributed to the presence of low density lipoproteins (LDL) that prevent cholesterol efflux by increasing membrane stability and resistance to low temperatures. (Moussa et al. 2002 Theriogenology 57, 1695–1706) demonstrated that the purification of LDL is possible, thereby allowing its use as a replacement for integral egg yolk in extender. Then, this study aimed to evaluate the effect of substitution of egg yolk by different LDL concentrations during cryopreservation of ram semen. A total of 6 sheep, 3 ejaculates per animal, were collected. After collection, the ejaculates were evaluated and diluted in different extenders: E1) Tris, glucose, 15% egg yolk, and 5% glycerol; E2) Tris, glucose, 5% LDL (Moussa et al. 2002 Theriogenology 57, 1695–1706), and 5% glycerol; E3) Tris, glucose, 10% LDL, and 5% glycerol; and E4) Tris, glucose, 20% LDL, and 5% glycerol. The samples were adjusted to a final concentration of 600 × 106 sptz mL–1 and filled into 0.25-mL straws and frozen in a TK 4000® machine. After thawing, sperm motility and spermatic vigor were evaluated, and the test of thermo-resistance (TTR) was conducted. Functional and structural integrity of the spermatic membrane were evaluated through the hypoosmotic test and the use of fluorescent dyes. The kinetic parameters of sperm were assessed by the computerized system (CASA). The statistical analysis was performed using the statistical program SAS (Statistical Analysis System), and the averages were compared using the Duncan multiple test. No difference (P > 0.05) was found between extenders for progressive motility after thawing. After 3 h of TTR, E1 showed higher values (P < 0.05) than E2, not differing from E4. The percentage of cells reactive to the hypoosmotic test was lower with the use of E2 (P < 0.05) than with other groups. Regarding the fluorescence technique, the average percentage of cells with intact membrane after thawing was higher in samples preserved in the extenders E1, E3, and E4 (P < 0.05) than in E2. Velocity average pathway (VAP), velocity straight line (VSL), and linearity of cryopreserved ram semen were (P < 0.05) significantly higher in E1 than in E2 and E3. The other kinetic parameters were similar in all groups tested. The results indicate that the extenders containing 10 and 20% of LDL are capable of protecting the spermatic cells during cryopreservation.

Research supported by the FAPESB.
Scenario analysis of alternative vegetation management options on the greenhouse gas budget of two grazing businesses in north-eastern Australia
Authors: Bray S. G. , Golden R.
Published: August 2011

The emerging carbon economy will have a major impact on grazing businesses because of significant livestock methane and land-use change emissions. Livestock methane emissions alone account for ~11% of Australia’s reported greenhouse gas emissions. Grazing businesses need to develop an understanding of their greenhouse gas impact and be able to assess the impact of alternative management options. This paper attempts to generate a greenhouse gas budget for two scenarios using a spread sheet model.
The first scenario was based on one land-type ‘20-year-old brigalow regrowth’ in the brigalow bioregion of southern-central Queensland. The 50 year analysis demonstrated the substantially different greenhouse gas outcomes and livestock carrying capacity for three alternative regrowth management options: retain regrowth (sequester 71.5 t carbon dioxide equivalents per hectare, CO2-e/ha), clear all regrowth (emit 42.8 t CO2-e/ha) and clear regrowth strips (emit 5.8 t CO2-e/ha). The second scenario was based on a ‘remnant eucalypt savanna-woodland’ land type in the Einasleigh Uplands bioregion of north Queensland. The four alternative vegetation management options were: retain current woodland structure (emit 7.4 t CO2-e/ha), allow woodland to thicken increasing tree basal area (sequester 20.7 t CO2-e/ha), thin trees less than 10 cm diameter (emit 8.9 t CO2-e/ha), and thin trees <20 cm diameter (emit 12.4 t CO2-e/ha).
Significant assumptions were required to complete the budgets due to gaps in current knowledge on the response of woody vegetation, soil carbon and non-CO2 soil emissions to management options and land-type at the property scale. The analyses indicate that there is scope for grazing businesses to choose alternative management options to influence their greenhouse gas budget. However, a key assumption is that accumulation of carbon or avoidance of emissions somewhere on a grazing business (e.g. in woody vegetation or soil) will be recognised as an offset for emissions elsewhere in the business (e.g. livestock methane). This issue will be a challenge for livestock industries and policy makers to work through in the coming years.
People seeking health information about human papillomavirus via the internet have a very high level of anxiety
Authors: Verhoeven Veronique , Baay Marc , Baay Pieter
Published: August 2011

A website with evidence-based information on human papillomavirus (HPV) has been developed at the University of Antwerp, Belgium. Visitors were asked to fill in a web-based form, including the State-Trait Anxiety Inventory (STAI), to obtain information on their profile. During the study period, 232 of 3638 (6.4%) visitors filled in the form. In our study, people looking for HPV information on the internet showed high anxiety levels. Three determinants contributed to the STAI score: a previous HPV-test, young age, and not feeling reassured by the website’s content. It is warranted that physicians counsel their patients on HPV-related issues in the context of cervical cancer screening.
Spatial and temporal patterns of feral pig diggings in rainforests of north Queensland
Authors: Mitchell J. , Dorney W. , Mayer R. , McIlroy J.
Published: August 2011

Feral pigs (Sus scrofa) are believed to have a severe negative impact on the ecological values of tropical rainforests in north Queensland, Australia. Most perceptions of the environmental impacts of feral pigs focus on their disturbance of the soil or surface material (diggings). Spatial and temporal patterns of feral pig diggings were identified in this study: most diggings occurred in the early dry season and predominantly in moist soil (swamp and creek) microhabitats, with only minimal pig diggings found elsewhere through the general forest floor. The overall mean daily pig diggings were 0.09% of the rainforest floor. Most diggings occurred 3–4 months after the month of maximum rainfall. Most pig diggings were recorded in highland swamps, with over 80% of the swamp areas dug by pigs at some time during the 18-month study period. These results suggest that management of feral pig impacts should focus on protecting swamp and creek microhabitats in the rainforest, which are preferred by pigs for digging and which have a high environmental significance.
Effects of a cooling collar on affect, ratings of perceived exertion, and running performance in the heat
Authors: Minniti Antoinette , Tyler Christopher J. , Sunderland Caroline
Published: August 2011

During prolonged exercise, ratings of perceived exertion (RPE) and affect (pleasure; activation) play an important role in performance, especially in hot conditions. Although various mechanisms have been tried to manage the effects of heat (e.g. cooling jackets), the purpose of the current research was to assess the effect of a cooling collar on RPE, affect, thermal sensation, and running performance in the heat. Participants (n =8) wore a cold collar, uncooled collar or no collar as they completed three 90‐min preloaded treadmill time‐trials in the heat (30.5±0.1°C), which included 75 min at ∼60% [Vdot]O2max followed by a 15‐min time‐trial. Affect, RPE, and thermal sensation were measured throughout. Performance during the time‐trial was significantly improved in the cold collar compared with the uncooled collar and no‐collar trials; however, pleasure and activation ratings were highest for the no‐collar trial. Findings suggest that a cooling collar may improve performance, but not necessarily “feel good”. Practically, it seems necessary to ensure sufficient education about the benefits, on balance, of the cold collar, while the performance improvements outweighed the reported discomfort of athletes in this study. In addition, the cold collar may prove quite beneficial for individuals who work in hot climates and or conditions, as it may be effective in minimizing discomfort associated with heat for other groups as well.
Comparison of anthropometric characteristics and sprint start performance between elite adolescent and adult sprint athletes
Authors: Aerenhouts Dirk , Delecluse Christophe , Hagman Friso , Taeymans Jan , Debaere Sofie , Van Gheluwe Bart , Clarys Peter
Published: August 2011

The aim of this study was to examine the physical characteristics and somatotype of junior and senior athletes in relation to sprint start and acceleration performance. Nineteen female junior, 23 male junior, 9 female senior, and 16 male senior sprint athletes performed three maximal 20‐m sprints. The starting blocks were instrumented to measure forward propulsion forces. Running velocity was measured by a laser positioned behind the athlete at 1 m height. Anthropometric measures were used to calculate somatotype and skeletal muscle mass. Body composition was estimated by underwater weighing densitometry. Junior and senior athletes were of similar height in both sexes. Male seniors were heavier, had larger limb circumferences, and a higher skeletal muscle mass than male juniors. Only the limb circumferences of the female seniors were larger than those of the female juniors. Female juniors were balanced ectomorphs, while female seniors were situated centrally on the somatochart (2.7–2.2–3.9 vs. 2.6–3.1–3.1; P=0.772, 0.047, and 0.066 respectively). Male juniors were mesomorphic ectomorphs, while male seniors were ectomorphic mesomorphs (1.8–3.3–3.6 vs. 1.6–4.2–2.8; P=0.148, 0.002, and 0.002 respectively). All sprint starts were similar for the junior and senior athletes of both sexes. Senior athletes accelerated more than the junior athletes, which resulted in higher running velocities after 5 m (senior vs. junior: females, 5.51±0.32 vs. 6.01±0.27 m · s–1, P=0.001; males, 5.85±0.38 vs. 6.13±0.44 m · s–1, P=0.043). The greater muscularity of senior compared with junior athletes did not result in better sprint start dynamics, but they did accelerate more and ran faster. These results show that late‐adolescent boys in particular are still developing their muscularity. The technical complexity of the sprint start and the negative influence of a higher body mass may partly explain the comparable sprint start dynamics of the junior and senior athletes. We suggest that strength training should be combined with sufficient attention to technical skills to allow a positive transfer.
Secondary warm‐up following stretching on vertical jumping, change of direction, and straight line speed
Authors: Pearce Alan J. , Latella Christopher , Kidgell Dawson J.
Published: August 2011

The aim of this study was to build on previous conflicting research on performance following stretching and secondary activity post‐stretching. Using a randomized, cross‐over design, 15 male participants completed a 5‐min warm‐up jog, followed by a maximal vertical jump (VJ1) and a repetitive five‐repetition jump (VJ5) on a force mat, an intervention (static stretching, dynamic range of movement stretching, or no‐stretching control), then a second maximal vertical jump and repetitive five‐repetition jump, followed by a change of direction test (505 test) and a straight line sprint (20‐m). Two‐way analysis of variance with repeated measures showed significant time and group × time interaction effects for both mean maximal VJ1 and VJ5 jump heights (P<0.001). Time course changes showed VJ1 jump height following static stretching was significantly reduced (7%) compared with the dynamic and control conditions, which improved by 5.0% and 3.9% (P = 0.02 and P = 0.04) respectively. Following the second bout of movement activity, VJ1 jump height had improved, but was not significantly different from baseline value (P = 0.11). Similarly, VJ5 jump height following static stretching was significantly reduced (6.2%) compared with the dynamic and control conditions, which showed improvements of 6.7% and 7.5% (P = 0.04 and P = 0.01) respectively. After the second bout of movement activity, mean VJ5 jump height for the static stretching group returned to baseline values (P = 0.84), while further improvements were observed in the dynamic (3.2%) and control groups (2.2%) (P = 0.01 and P = 0.04 respectively). Significant improvements in the 505 test were observed in the dynamic and control conditions, in both legs (range 2.45–3.67%; P<0.001), compared with the static stretching condition. Although sprint time improved following the second bout of movement activity, no differences were observed in the 20‐m sprint between conditions. The results of this study confirm previous findings that static stretching reduces vertical jump height that is not reversed with follow‐up movement activity. Moreover, the results show that activities requiring rapid changes of direction and speed may also be affected if preceded by a bout of static stretching, and is not reversed with follow‐up movement activities.
Maximal lactate steady‐state and anaerobic thresholds from different methods in cyclists
Authors: Grossl Talita , De Lucas Ricardo Dantas , De Souza Kristopher Mendes , Antonacci Guglielmo Luiz Guilherme
Published: August 2011

The lactate anaerobic threshold (AT) determined during an incremental test has been used generally to estimate the maximal lactate steady‐state intensity (MLSSint) in several sports. Furthermore, this index could be useful to predict the time‐trial cycling performance and also to prescribe training intensity to enhance aerobic capacity. The aim of this study was to compare three different AT estimations with actual MLSSint in trained cyclists. Fourteen trained cyclists participated in this study. They had previously performed a maximal incremental cycling test (35 W increments each 3 min) in a laboratory followed by three to five visits to measure the MLSSint (30‐min tests). Blood lactate concentration ([La]), oxygen uptake ([Vdot]O2), and heart rate (HR) were measured during all tests. Based on the incremental test, we calculated three ATs using different proposed methods: AT1‐intensity corresponds to fixed [La]; AT2‐minimum equivalent of the blood lactate‐power output relationship plus 1.5 mmol·L−1; AT3‐power output of the stage antecedent to the second lactate increase of at least 0.5 mmol·L−1 above the previous values, where the second increase was greater than the first. The MLSSint was determined for each participant as the highest power output that could be maintained with [La] fluctuating less than 1 mmol·L−1 during the final 20 min of the steady‐state tests. ANOVA with repeated measures was used to compare physiological variables in the different methods. The relationship between the MLSSint and the power output of AT1, AT2, and AT3 was analysed using Pearson product‐moment correlation coefficients. In addition, we calculated the bias and limits of agreement between the three different methods with actual MLSSint. The mean±s values of power output related to MLSSint, AT1, AT2, and AT3 were 247±33 W, 258±39 W, 248±35 W, and 230±36 W, respectively. The results showed that AT3 underestimated (P <0.05) the MLSSint for most of the participants and provided lower mean values compared with AT1 and AT2. Furthermore, AT2 seems to be more accurate to estimate MLSSint than other methods here verified when we analysed the mean values, correlation coefficient (r = 0.94), and Bland‐Altman limits of agreement (± 9.5%). The AT1 also provided good prediction values, although it presented with a trend to overestimate MLSSint. Therefore, considering the methods analysed in the current study and the importance of this submaximal aerobic index to flat time‐trials and prolonged uphill cycling performance, the AT2 method could be used with good accuracy by coaches and athletes.
Ion beam guiding with straight and curved Teflon tubes
Authors: Kojima Takao M , Ikeda Tokihiro , Kanai Yasuyuki , Yamazaki Yasunori , Esaulov Vladimir A
Published: August 2011

In an effort to develop a flexible ion beam guiding scheme, the guiding capabilities of straight and curved Teflon tubes were tested with 8 keV Ar8+ ions. The tubes used were about 50 mm long and of 1 mm/2 mm inner and outer diameters. One was straight, and the others were bent with different radii of curvature corresponding to bending angles from 9.6° to 26.7°. Transmission of several tens of per cent of the injected beam was observed for the curved tubes, while transmission through the tilted straight tube vanished when the tilt was more than 7°. This demonstrates the possibility of efficient ion beam guiding with flexible insulator tubes.
Role of N2 molecules in pulse discharge production of I atoms for a pulsed chemical oxygen–iodine laser
Authors: Kochetov I V , Napartovich A P , Vagin N P , Yuryshev N N
Published: August 2011

A pulsed electric discharge is the most effective means to turn chemical oxygen–iodine laser (COIL) operation into the pulse mode by fast production of iodine atoms. Experimental studies and numerical simulations are performed on a pulsed COIL initiated by an electric discharge in a mixture CF3I : N2 : O2(3
X) : O2(a 
1Δg) flowing out of a chemical singlet oxygen generator. A transverse pulsed discharge is realized at various iodide pressures. The model comprises a system of kinetic equations for neutral and charged species, the electric circuit equation, the gas thermal balance equation and the photon balance equation. Reaction rate coefficients for processes involving electrons are repeatedly re-calculated by the electron Boltzmann equation solver when the plasma parameters are changed. The processes accounted for in the Boltzmann equation include direct and stepwise excitation and ionization of atoms and molecules, dissociation of molecules, electron attachment processes, electron–ion recombination, electron–electron collisions and second-kind collisions. The last processes are particularly important because of a high singlet oxygen concentration in gas flow from the singlet oxygen chemical generator. A conclusion is drawn about satisfactory agreement between the theory and the experiment.
Schottky barrier effect on the electrical properties of Fe3O4/ZnO and Fe3O4/Nb : SrTiO3 heterostructures
Authors: Yang Kiwon , Kim D H , Dho Joonghoe
Published: August 2011

The current–voltage (I–V) characteristics of Fe3O4/Nb-doped SrTiO3(Nb : STO) and Fe3O4/ZnO junctions prepared by pulsed laser deposition were investigated as a function of temperature. The rectifying behaviour was more distinctive in Fe3O4/Nb : STO than in the Fe3O4/ZnO. Contrary to Fe3O4/Nb : STO, remarkably, the current flow in Fe3O4/ZnO was slightly larger for negative bias voltages than for positive bias voltages. The threshold voltage in Fe3O4/Nb : STO dramatically shifted to a higher voltage by decreasing the temperature, and hysteresis behaviour with a cyclic voltage sweep appeared below 120 K. Upon cooling, the rectifying behaviour in Fe3O4/ZnO gradually disappeared within the measurement range. The observed difference between Fe3O4/Nb : STO and Fe3O4/ZnO could be explained by the shape and height of the Schottky barrier which was determined by the relative magnitude of the work functions of the two contact materials. The formation of the Schottky barrier presumably resulted from an upward shift of the interface band in Fe3O4/Nb : STO, while a little downward shift of the interface band occurred in Fe3O4/ZnO. In addition, Al-doping into ZnO induced a complete disappearance of the Schottky barrier in the Fe3O4/Al-doped ZnO junction.
Optimization mechanism of CaSi2O2N2 : Eu2+phosphor by La3+ion doping
Authors: Yang L X , Xu X , Hao L Y , Wang Y F , Yin L J , Yang X F , He W , Li Q X
Published: August 2011

La3+(lanthanide 3+) ion doping may significantly improve the photoluminescence properties of CaSi2O2N2 : Eu2+, a potential yellow–green phosphor for ultraviolet or blue light-emitting diodes. The optimization mechanism was studied in detail by the case of La3+doping. The La3+ions could stabilize Ca2+vacancies, inhibit the oxidization of Eu2+to Eu3+, based on x-ray photoelectron spectroscopy, x-ray absorption near-edge structure measurements and first-principles calculations. Consequently, not only could the total number of activators be increased, but also the non-radiative transition probability between Eu2+and Eu3+could be reduced as a result of La3+doping. It was also observed that the photoluminescence of CaSi2O2N2 : Eu2+phosphors could be enhanced by the addition of many La3+ions, but not Sm3+and Yb3+ions, which confirmed the mechanism.
AlGaN/GaN-based HEMTs for electrical stimulation of neuronal cell cultures
Authors: Witte H , Warnke C , Voigt T , de Lima A , Ivanov I , Vidakovic-Koch T R , Sundmacher K , Krost A
Published: August 2011

Unipolar source–drain voltage pulses of GaN/AlGaN-high electron mobility transistors (HEMTs) were used for stimulation of cultured neuronal networks obtained from embryonic rat cerebral cortex. The HEMT sensor was grown by metal organic vapour phase epitaxy on a 2 inch sapphire substrate consisting of 10 single HEMTs concentrically arranged around the wafer centre. Electrolytic reactions between the HEMT sensor surface and the culture medium were not detected using cyclic voltammetry.

During voltage pulses and resulting neuronal excitation, capacitances were recharged giving indications of the contributions of the AlGaN and AlO
x
isolation layers between the two-dimensional electron gas channel and the neuron culture. The resulting threshold current for stimulation of neuron activity strongly depended on the culture and HEMT position on the sensor surface under consideration which was caused by different impedances of each neuron culture and position within the culture. The differences of culture impedances could be explained by variations of composition, thickness and conductivity of the culture areas.
Novel rapid shutdown strategies for runaway electron suppression in DIII-D
Authors: Commaux N. , Baylor L.R. , Combs S.K. , Eidietis N.W. , Evans T.E. , Foust C.R. , Hollmann E.M. , Humphreys D.A. , Izzo V.A. , James A.N. , Jernigan T.C. , Meitner S.J. , Parks P.B. , Wesley J.C. , Yu J.H.
Published: August 2011

New rapid shutdown strategies have been recently tested in the DIII-D tokamak to mitigate runaway electrons (REs). Disruptions in ITER are predicted to generate multi-MeV REs that could damage the machine. The RE population in large tokamaks is expected to be dominated by avalanche amplification which can be mitigated at high density levels by collisional drag. Particle injection schemes for collisional suppression of RE have been developed and tested in ITER-relevant scenarios: massive gas injection, shattered pellet injection (SPI) and shell pellet injection. The results show an improved penetration of particles injected with the SPI. Another strategy has been developed to harmlessly deconfine REs by applying a non-axisymmetric magnetic perturbation to worsen their confinement. This technique appeared to deconfine seed RE before the avalanche process could amplify the RE beam. The last method tested was to use the plasma position control system on the RE beam to prevent it from contacting the wall. This proved effective in preventing high current RE beam from touching the wall and providing more time to mitigate an existing RE beam but a successful ‘soft landing’ (without fast final losses) of the RE has not been observed yet.