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1

Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study  

PubMed Central

Objective To examine the clinical pregnancy rate (CPR) and multiple pregnancy rate (MPR) in a large in vitro fertilisation (IVF) programme before and after the introduction of single blastocyst transfer (SBT) strategy in a selected group of women. Design A 3-year pre- and postintervention study. Setting A tertiary reproductive medicine and assisted conception unit in a London teaching hospital. Population Two thousand four hundred and fifty-one fresh IVF cycles performed between July 2004 and June 2007 at the Assisted Conception Unit at Guy’s and St Thomas’ Hospital NHS Foundation Trust were included in the study. Methods In January 2006, we implemented a multidisciplinary intervention involving the introduction of a selective day 5 SBT service together with an educational programme on the risks of multiple pregnancy and potential advantages of blastocyst transfer aimed at couples at high risk of multiple pregnancy. Main outcome measures The CPR per cycle started and MPR per clinical pregnancy achieved. Results A statistically significant increase in the CPR from 27% (324/1198) to 32% (395/1253) (risk difference [RD] 5%, risk ratio [RR] 1.17, 95% CI 1.03–1.32, P = 0.015) and reduction in the MPR per clinical pregnancy from 32% (103/272) to 17% (69/395) (RD 15%, RR 0.46, 95% CI 0.35–0.60, P < 0.001) were observed after introduction of the SBT service. Conclusion Selective SBT in women with good prognosis can reduce the MPR after IVF while maintaining the overall success rate of the IVF programme. Please cite this paper as:Khalaf Y, El-Toukhy T, Coomarasamy A, Kamal A, Bolton V, Braude P. Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study. BJOG 2008;115:385–390. PMID:18190376

Khalaf, Y; El-Toukhy, T; Coomarasamy, A; Kamal, A; Bolton, V; Braude, P

2008-01-01

2

Monozygotic twins and transfer at the blastocyst stage after ICSI.  

PubMed

The incidence of monozygotic twinning (MZT) is higher in pregnancies conceived after assisted reproduction than after natural conception. Alterations, produced by ovarian stimulation, in-vitro culture conditions and specifically alterations of zona pellucida are mentioned as possible causes of this phenomenon. A retrospective review was performed of the incidence of MZT in pregnancies generated in our centre during the period of January 1996 to December 1999. This variable was compared in 129 gestations that resulted from blastocyst transfer (occurring from September 1998 to August 1999) with 814 pregnancies produced by transfers of 4- to 8-cell embryos. Follicular development was induced with human menopausal gonadotrophin and urinary FSH during 1996 and 1997 and with recombinant FSH during 1998 and 1999. Blastocysts were cultured in sequential media using S1 or G1 up to 72 h and S2 or G2 to day 5. Five of the 129 pregnancies generated by blastocyst transfers were complicated by MZT gestation (3.9%). In comparison, only six of 814 pregnancies occurred from 4- to 8-cell transfers (0.7%), a difference that is statistically significant (P< 0.001 with Yates correction). The results confirm an increase of MZT in pregnancies from intracytoplasmic sperm injection as compared to the natural incidence. Moreover, the frequency of MZT was significantly higher when transfers were performed at the blastocyst stage, suggesting that extended in-vitro culture of embryos may be associated with alterations of the zona pellucida and the hatching process. PMID:11157829

da Costa AL, A L; Abdelmassih, S; de Oliveira, F G; Abdelmassih, V; Abdelmassih, R; Nagy, Z P; Balmaceda, J P

2001-02-01

3

Mosaic pregnancy after transfer of a “euploid” blastocyst screened by DNA microarray  

PubMed Central

Background High proportions of human embryos produced by in vitro fertilization are aneuploidy and mosaic. DNA microarray is one of the most practical screening methods to select euploid embryos for transfer. However, mosaic pregnancy is still possible due to embryonic mosacism. Here we report a successful pregnancy after transfer of a mosaic blastocyst with euploid inner cell mass. Methods A woman with a previous trisomy 13 pregnancy pursued infertility treatment with preimplantation genetic screening by a trophectoderm biopsy and DNA microarray. NimbleGen oligonucleotide DNA microarray was applied to biopsied samples from 13 blastocysts. A euploid blastocyst was transferred to the patient and subsequent prenatal cytogenetic tests were performed by FISH and/or G banding. Results Following DNA microarray, it was found that 5 blastocysts were euploid and 8 were aneuploidy. Transfer of one euploid blastocyst resulted in a clinical pregnancy. Prenatal cytogenetic tests of samples biopsied from chorionic villi sample showed both trisomy 21 (47 XX, +21) and euploid (46, XX) cells. Further prenatal cytogenetic test with a sample from amniotic fluid indicated that all cells were euploid (46, XX). The pregnancy was continued and a healthy girl was delivered after 41 weeks of gestation. Conclusions This is the first report to indicate a mosaic pregnancy after transfer of a “euploid” blastocyst that was screened by DNA microarray, and the case further confirms that mosaicism is present in human blastocysts produced by in vitro fertilization. PMID:24098936

2013-01-01

4

A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization  

Microsoft Academic Search

The effectiveness of blastocyst culture and transfer in human in-vitro fertilization (IVF) was evaluated in a prospective randomized trial in patients having a moderate to good response to gonadotrophin stimulation. Embryos were transferred either on day 3 after culture to around the 8-cell stage in Ham's F-10 medium supplemented with fetal cord serum, or on day 5 after culture to

David K. Gardner; William B. Schoolcraft; Lyla Wagley; Terry Schlenker; John Stevens; John Hesla

1999-01-01

5

Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs  

Microsoft Academic Search

Objective: To determine whether previously described advanced blastocyst development and high implantation rates are confirmed in an expanded multicenter trial.Design: Retrospective review.Setting: Two private assisted reproductive technology units.Patient(s): One hundred seventy-four patients who underwent blastocyst culture and transfer.Intervention(s): Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5) followed by ET.Main Outcome Measure(s): The number and

William B Schoolcraft; David K Gardner; Terry Schlenker; David R Meldrum

1999-01-01

6

Blastocyst transfer after aseptic vitrification of zygotes: an approach to overcome an impaired uterine environment.  

PubMed

In some IVF cycles, no fresh embryo transfer in the stimulated cycle is advisable. The cryopreservation of zygotes and the transfer of blastocysts in a cryo-embryo transfer is an option to circumvent an inadequate uterine environment due to risk of ovarian hyperstimulation syndrome, inappropriate endometrium build up, endometrial polyps or uterine myomas. For this strategy, highly secure and safe cryopreservation protocols are advisable. This study describes a protocol for aseptic vitrification of zygotes that results in high survival rates and minimizes the potential risk of contamination in liquid nitrogen during cooling and long-term storage. In mouse zygotes, there was no difference in efficiency as compared with a conventional open vitrification system. In IVF patients, aseptically vitrified zygotes showed no difference in blastocyst formation rate as compared with sibling zygotes kept in fresh culture. A clinical study comprising 173 cryo-cycles with a transfer of blastocysts originating from vitrified zygotes showed an ongoing pregnancy rate of 40.9%. The live birth rate per patient was 36.8%. A combination of good clinical results and increased safety conditions due to aseptic vitrification encourages the use of cryo-embryo transfer for patients with a suboptimal uterine environment in a fresh cycle. In stimulated IVF cycles, high doses of hormones are given to stimulate multifollicular growth. One drawback of the hormonal substitution is that the uterine environment is not at the same time optimally prepared for embryo implantation. A solution, which is increasingly under discussion, is to cryopreserve the embryos obtained in the stimulated cycle and to transfer them back into the optimal uterine environment in a subsequent cryo-cycle. This procedure requires highly secure and safe cryopreservation protocols in order to ensure benefits for both pregnancy and birth rates. We have established a protocol for the vitrification of zygote-stage embryos in aseptic devices, which minimize the potential risk of contamination during cooling and storage. The vitrified zygotes showed the same blastocyst development as compared with sibling zygotes in fresh culture. A clinical study comprising 173 cryo-cycles with transfer of blastocysts originating from vitrified zygotes shows an ongoing pregnancy rate of 40.9%. The live birth rate per patient was 36.8%. A combination of good clinical results and increased safety conditions due to aseptic vitrification conditions contributes to a change in transfer strategy and encourages us to increase the cryo-embryo transfer rate for an optimal uterine environment. PMID:23069744

Vanderzwalmen, Pierre; Zech, Nicolas H; Ectors, Fabien; Stecher, Astrid; Lejeune, Bernard; Vanderzwalmen, Sabine; Wirleitner, Barbara

2012-12-01

7

Monozygotic twins and transfer at the blastocyst stage after ICSI  

Microsoft Academic Search

MZT gestation (3.9%). In comparison, only six of 814 pregnancies occurred from 4- to 8-cell transfers (0.7%), a difference that is statistically significant (P < 0.001 with Yates correction). The results confirm an increase of MZT in pregnancies from intracytoplasmic sperm injection as compared to the natural incidence. Moreover, the frequency of MZT was significantly higher when transfers were performed

A. L. E. da Costa; S. Abdelmassih; F. G. de Oliveira; V. Abdelmassih; R. Abdelmassih; Z. P. Nagy; J. P. Balmaceda

2001-01-01

8

Aspects of in vivo oocyte production, blastocyst development, and embryo transfer in the cat.  

PubMed

A brief overview of the progress made during the past approximately 40 years on the development of methods for in vitro production of cat embryos and intra- and interspecies embryo transfer is described. The presentation is focused primarily on research done over the past 30 years at the Cincinnati Zoo (1980-1995) and at the Audubon Nature Institute, New Orleans (1996-present) beginning with original studies on determining optimal doses of porcine FSH for ovarian stimulation and uterine embryo recovery, cryopreservation, and transfer. A key early finding was the ability of cats to respond to multiple gonadotropin (porcine FSH) treatments by repeated stimulation of follicular development. With a ? 6-month interval between FSH treatments, over the past 15 years (1998-2013), we have done 1603 laparoscopic oocyte retrievals on 337 cats and recovered >38,000 mature oocytes (mean = 24.1 per laparoscopic oocyte retrieval). The limited information available on in vivo blastocyst development in the cat during the latter portion of the preimplantation period (approximately Days 8 to 12 after coitum or approximately Days 7 to 11 after ovulation) was assembled for the purpose of comparing and contrasting it with the growth, expansion, and zona functioning of in vitro-derived blastocysts. Also, results of transferring morulae and/or blastocysts into synchronous recipients are described to emphasize evidence that appears to allude to an essential role for an intact zona pellucida in successful implantation and subsequent development in the cat. Until 2003, our in vitro-derived embryos were transferred into the uterine horns of recipients to determine the feasibility of producing offspring from such primary methods as IVF, intracytoplasmic sperm injection, SCNT, and embryo cryopreservation. With the exception of SCNT embryos, pregnancy rates were satisfactory, but embryo survival rates were not. Subsequently, after finding that SCNT embryo survival rate could be improved using laparoscopic transfer of early cleavage stage embryos into the oviduct, we applied the technique to embryos derived using IVF with sex-sorted sperm, oocyte vitrification, and embryo cryopreservation. Overall, a pregnancy rate of 67% (14/21) has resulted. Most recently, with the oviductal embryo transfer technique, two litters of Black-Footed cat kittens have been born from intra- and interspecies transfer of cryopreserved embryos. PMID:24274417

Pope, C E

2014-01-01

9

Rare association of ovarian implantation site for patients with heterotopic and with primary ectopic pregnancies after ICSI and blastocyst transfer  

Microsoft Academic Search

Two cases of patients with ruptured ovarian pregnancies (P1 ovarian heterotopic and P2 primary ovarian ectopic) after intracytoplasmic sperm injection and blastocyst transfer are presented. Laparoscopy was performed on day 40 and day 27 after transfer in cases P1 and P2 respectively. In both cases the ectopic pregnancies were located on the left ovary and were successfully removed by laparoscopy

Flavio Garcia Oliveira; Vicente Abdelmassih; AndreLuiz Eigenheer Costa; JosePedro Balmaceda; Soraya Abdelmassih; Roger Abdelmassih

10

Blastocyst-stage versus cleavage-stage embryo transfer in women with high oestradiol concentrations: randomized controlled trial.  

PubMed

This prospective, randomized, controlled trial tested the hypothesis that delaying embryo transfer to the blastocyst stage can increase the probability of clinical pregnancy and live birth in women with high oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) undergoing intracytoplasmic sperm injection using the long protocol. A total of 200 women with oestradiol >3000 pg/ml on the HCG day with four or more good-quality, day-3 embryos were randomized in a 1:1 ratio to undergo day-3 or day-5 embryo transfer. Clinical pregnancy rates (CPR; 41% versus 59%; relative risk 0.70, 95% CI 0.52–0.93) and ongoing pregnancy/live-birth rates (35% versus 52%; relative risk 0.67, 95% CI 0.46–0.93) were lower in women undergoing cleavage-stage than blastocyst-stage embryo transfer. Using receiver operating characteristic curves, among women undergoing cleavage-stage embryo transfer, a detrimental cut-off value for not achieving pregnancy for oestradiol was 4200 pg/ml, with lower CPR and ongoing pregnancy/live-birth rates (P = 0.006 and 0.02, respectively). No detrimental cut-off value for oestradiol was identified among women undergoing blastocyst-stage embryo transfer. Delaying embryo transfer to the blastocyst stage can increase the probability of pregnancy in women with high oestradiol on the HCG day PMID:22050864

Elgindy, Eman A; Abou-Setta, Ahmed M; Mostafa, Magdy I

2011-12-01

11

Rare association of ovarian implantation site for patients with heterotopic and with primary ectopic pregnancies after ICSI and blastocyst transfer.  

PubMed

Two cases of patients with ruptured ovarian pregnancies (P1 = ovarian heterotopic and P2 = primary ovarian ectopic) after intracytoplasmic sperm injection and blastocyst transfer are presented. Laparoscopy was performed on day 40 and day 27 after transfer in cases P1 and P2 respectively. In both cases the ectopic pregnancies were located on the left ovary and were successfully removed by laparoscopy preserving the ovaries. In case P1 the intrauterine pregnancy was not affected. A healthy boy was born after 37 weeks of pregnancy. In this way, potential fertility of the patients and the intrauterine pregnancy were maintained. These cases occurred during a series of blastocyst transfers in which 129 pregnancies were obtained. There were no cases of ovarian ectopic/heterotopic pregnancies from January 1996 to September 1999 in 814 pregnancies obtained from day 2 or day 3 embryo transfers. Because the ovarian ectopic pregnancies occurred in patients with day 5 embryo transfer who otherwise did not have any predisposing factors for ectopic pregnancy, it is advisable to conduct a large scale analysis of future data about the possible association between blastocyst-stage embryo transfer and the somewhat higher risk of unexpected complications of clinical outcome. PMID:11574520

Oliveira, F G; Abdelmassih, V; Costa, A L; Balmaceda, J P; Abdelmassih, S; Abdelmassih, R

2001-10-01

12

Analysis of embryo morphokinetics, multinucleation and cleavage anomalies using continuous time-lapse monitoring in blastocyst transfer cycles  

PubMed Central

Background Time-lapse imaging combined with embryo morphokinetics may offer a non-invasive means for improving embryo selection. Data from clinics worldwide are necessary to compare and ultimately develop embryo classifications models using kinetic data. The primary objective of this study was to determine if there were kinetic differences between embryos with limited potential and those more often associated with in vitro blastocyst formation and/or implantation. We also wanted to compare putative kinetic markers for embryo selection as proposed by other laboratories to what we were observing in our own laboratory setting. Methods Kinetic data and cycle outcomes were retrospectively analyzed in patients age 39 and younger with 7 or more zygotes cultured in the Embryoscope. Timing of specific events from the point of insemination were determined using time-lapse (TL) imaging. The following kinetic markers were assessed: time to syngamy (tPNf), t2, time to two cells (c), 3c (t3), 4c ( t4), 5c (t5), 8c (t8), morula (tMor), start of blastulation (tSB); tBL, blastocyst (tBL); expanded blastocyst (tEBL). Durations of the second (cc2) and third (cc3) cell cycles, the t5-t2 interval as well as time to complete synchronous divisions s1, s2 and s3 were calculated. Incidence and impact on development of nuclear and cleavage anomalies were also assessed. Results A total of 648 embryos transferred on day 5 were analyzed. The clinical pregnancy and implantation rate were 72% and 50%, respectively. Morphokinetic data showed that tPNf, t2,t4, t8, s1, s2,s3 and cc2 were significantly different in embryos forming blastocysts (ET or frozen) versus those with limited potential either failing to blastulate or else forming poor quality blastocysts ,ultimately discarded. Comparison of embryo kinetics in cycles with all embryos implanting (KID+) versus no implantation (KID-) suggested that markers of embryo competence to implant may be different from ability to form a blastocyst. The incidence of multinucleation and reverse cleavage amongst the embryos observed was 25% and 7%, respectively. Over 40% of embryos exhibiting these characteristics did however form blastocysts meeting our criteria for freezing. Conclusions These data provide us with a platform with which to potentially enhance embryo selection for transfer. PMID:24951056

2014-01-01

13

Uncoupled Embryonic and Extra-Embryonic Tissues Compromise Blastocyst Development after Somatic Cell Nuclear Transfer  

PubMed Central

Somatic cell nuclear transfer (SCNT) is the most efficient cell reprogramming technique available, especially when working with bovine species. Although SCNT blastocysts performed equally well or better than controls in the weeks following embryo transfer at Day 7, elongation and gastrulation defects were observed prior to implantation. To understand the developmental implications of embryonic/extra-embryonic interactions, the morphological and molecular features of elongating and gastrulating tissues were analysed. At Day 18, 30 SCNT conceptuses were compared to 20 controls (AI and IVP: 10 conceptuses each); one-half of the SCNT conceptuses appeared normal while the other half showed signs of atypical elongation and gastrulation. SCNT was also associated with a high incidence of discordance in embryonic and extra-embryonic patterns, as evidenced by morphological and molecular “uncoupling”. Elongation appeared to be secondarily affected; only 3 of 30 conceptuses had abnormally elongated shapes and there were very few differences in gene expression when they were compared to the controls. However, some of these differences could be linked to defects in microvilli formation or extracellular matrix composition and could thus impact extra-embryonic functions. In contrast to elongation, gastrulation stages included embryonic defects that likely affected the hypoblast, the epiblast, or the early stages of their differentiation. When taking into account SCNT conceptus somatic origin, i.e. the reprogramming efficiency of each bovine ear fibroblast (Low: 0029, Med: 7711, High: 5538), we found that embryonic abnormalities or severe embryonic/extra-embryonic uncoupling were more tightly correlated to embryo loss at implantation than were elongation defects. Alternatively, extra-embryonic differences between SCNT and control conceptuses at Day 18 were related to molecular plasticity (high efficiency/high plasticity) and subsequent pregnancy loss. Finally, because it alters re-differentiation processes in vivo, SCNT reprogramming highlights temporally and spatially restricted interactions among cells and tissues in a unique way. PMID:22701625

Degrelle, Séverine A.; Jaffrezic, Florence; Campion, Evelyne; Lê Cao, Kim-Anh; Le Bourhis, Daniel; Richard, Christophe; Rodde, Nathalie; Fleurot, Renaud; Everts, Robin E.; Lecardonnel, Jérôme; Heyman, Yvan; Vignon, Xavier; Tian, Xiuchun C.; Lewin, Harris A.; Renard, Jean-Paul; Hue, Isabelle

2012-01-01

14

Improved blastocyst development of single cow OPU-derived presumptive zygotes by group culture with agarose-embedded helper embryos  

PubMed Central

Background The in vitro culture of presumed zygotes derived from single cow ovum pick-up (OPU) is important for the production of quality blastocysts maintaining pedigree. The aim of the present study was to evaluate the agar chip-embedded helper embryo coculture system for single cow OPU-derived zygotes by assessing embryo quality. Methods Cumulus oocyte complexes (COCs) were collected from Hanwoo cows with high genetic merit twice a week using the ultra-sound guided OPU technique and from slaughterhouse ovaries. The Hanwoo cow COCs and slaughterhouse ovaries were matured in vitro, fertilized in vitro with thawed Hanwoo sperm and cultured for 24 h. The presumed zygotes were subsequently placed in three different culture systems: (1) control OPU (controlOPU) with single cow OPU-derived presumed zygotes (2~8); (2) agar chip-embedded slaughterhouse helper embryo coculture (agarOPU) with ten presumed zygotes including all presumed zygotes from a cow (2~8) and the rest from agar chip-embedded slaughterhouse presumed zygotes (8~2); and (3) slaughterhouse in vitro embryo production (sIVP) with ten slaughterhouse ovary-derived presumed zygotes, each in 50 ?L droplets. Day 8 blastocysts were assayed for apoptosis and gene expression using real time PCR. Results The coculture system promoted higher blastocyst development in OPU zygotes compared to control OPU zygotes cultured alone (35.2 vs. 13.9%; P < 0.01). Genes predicted to be involved in implantation failure and/or embryo resorption were down-regulated (P < 0.05) in control OPU zygotes (CD9, 0.4-fold; AKRAB1, 0.3-fold) and in cocultured zygotes (CD9, 0.3-fold; AKRAB1, 0.3-fold) compared to sIVP blastocysts (1.0-fold). Moreover, genes involved in implantation and/or normal calf delivery were up-regulated (P < 0.05 to P < 0.01) in control OPU zygotes (PGSH2, 5.0-fold; TXN, 4.3-fold; PLAU, 1.7-fold) and cocultured zygotes (PGSH2, 14.5-fold; TXN, 3.2-fold; PLAU, 6.8-fold) compared to sIVP (1.0-fold) blastocysts. However, the expression of PLAC8, TGF-?1, ODC1, ATP5A1 and CASP3 did not differ between the three culture groups. Conclusions Results show that the agar chip-embedded helper embryo coculture system enhances developmental competence and embryo quality in cultures of limited numbers of high pedigree single cow OPU presumed zygotes. PMID:21864328

2011-01-01

15

Constitutive expression of the embryonic stem cell marker OCT4 in bovine somatic donor cells influences blastocysts rate and quality after nucleus transfer.  

PubMed

Nuclear transfer (NT) is associated with epigenetic reprogramming of donor cells. Expression of certain genes in these cells might facilitate their expression in the NT embryo. This research was aimed to investigate the effect of constitutive expression of OCT4 in bovine somatic cells used for NT on the developmental potential of derived cloned embryos as well as in the expression of pluripotency markers in the Day-7 resulting embryos. Cloned blastocysts were generated from five cell lines that expressed OCT4. Pools of blastocysts were screened to detect OCT4, SOX2, and NANOG by qPCR. In vitro-fertilized time-matched blastocysts were used as controls. The development potential was assessed on the basis of blastocysts rate; grading and total cell counts at Day 7. OCT4 expression in the cell lines positively correlates with blastocysts rate (r = 0.92; p = 0.02), number of grade I blastocysts (r = 0.96; p = 0.01), and total cell number (r = 0.98; p = 0.002). The high expression of OCT4 in the cell line did not improve the final outcome of cloning. Somatic expression of OCT4 lead to increased expression of OCT4 and SOX2 in cloned grade I blastocysts; however, there was a bigger variability in OCT4 and SOX2 (p = 0.03; p = 0.02) expression in the embryos generated from cells expressing highest levels of OCT4. Probably the higher variability in OCT4 expression in cloned embryos is due to incorrect reprogramming and incapability of the oocyte to correct for higher OCT4 levels. For that reason, we concluded that OCT4 expression in somatic cells is not a good prognosis marker for selecting cell lines. PMID:23846396

Rodríguez-Alvarez, Lleretny; Manriquez, Jose; Velasquez, Alejandra; Castro, Fidel Ovidio

2013-10-01

16

A comparative study between cleavage stage embryo transfer at day 3 and blastocyst stage transfer at day 5 in in-vitro fertilization/intra-cytoplasmic sperm injection on clinical pregnancy rates  

PubMed Central

OBJECTIVE: To evaluate the efficacy of blastocyst transfer in comparison with cleavage stage transfer. STUDY DESIGN: A randomized, prospective study was conducted in Infertility clinic, Department of Obstetrics and Gynecology, Mahatma Gandhi Hospital, Jaipur on 300 patients aged 25-40 years undergoing in-vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI) cycle from May 2010-April 2011. When three or more Grade-I embryos were observed on day 2 of culture, patients were divided randomly into two study groups, cleavage stage transfer and blastocyst transfer group having 150 patients each. Primary outcomes evaluated were, Clinical pregnancy rate and Implantation rate. The results were analyzed using proportions, standard deviation and Chi-square test. RESULTS: Both the groups were similar for age, indication and number of embryos transferred. Clinical pregnancies after blastocyst transfer were significantly higher 66 (44.0%) compared to cleavage stage embryo transfer 44 (29.33%) (P < 0.01). Implantation rate for blastocyst transfer group was also significantly higher (P < 0.001). CONCLUSION: Blastocyst transfer having higher implantation rate and clinical pregnancy rate lead to reduction in multiple pregnancies. PMID:25395745

Kaur, Prabhleen; Swarankar, M. L.; Maheshwari, Manju; Acharya, Veena

2014-01-01

17

Comparison between Cleavage Stage versus Blastocyst Stage Embryo Transfer in an Egyptian Cohort Undergoing in vitro Fertilization: A Possible Role for Laser Assisted Hatching  

PubMed Central

Background Extended in vitro embryo culture and blastocyst transfer have emerged as essential components of the advanced reproductive technology armamentarium, permitting selection of more advanced embryos considered best suited for transfer. Aim of study The aim of this study was to compare between cleavage stage and blastocyst stage embryo transfer in patients undergoing intracytoplasmic sperm injection, and to assess the role of assisted hatching technique in patients undergoing blastocyst transfer. Patients and methods This study was carried out on two groups. Group I: 110 patients who underwent 120 cycles of intracytoplasmic sperm injection with day 2–3 embryo transfer—for unexplained infertility or male factor within the previous 3 years. Their data obtained retrospectively from medical records. Group II: 46 age matched infertile female patients undergoing 51 intracytoplasmic sperm injection cycles for similar causes. Patients in Group II were further subdivided into 2 equal subgroups; Group IIa (23 patients), which had laser assisted hatching and Group IIb (23 patients), which did not have assisted hatching. All patients had an infertility workup including basal hormonal profile, pelvic ultrasound, hysterosalpingogram and/or laparoscope and semen analysis of the patient’s partner. All patients underwent controlled ovarian hyperstimulation: Using long protocol of ovulation induction. Laser assisted hatching was done for blastocysts of 23 patients. Results Comparison between both groups as regards the reproductive outcome showed a significant difference in pregnancy and implantation rates, both being higher in group II (P < 0.05) Comparison between both subgroups as regards the reproductive outcome showed a highly significant difference in pregnancy and implantation rates, both being higher in Group IIa (P < 0.01). There was also a significantly higher rate of multiple pregnancies among Group IIa (P < 0.05). Conclusion Blastocyst transfer is a successful and improved alternative for patients with multiple failed in vitro fertilization attempts, associated with a significant increase in pregnancy and implantation rates. Furthermore, laser assisted hatching increases implantation and clinical pregnancy rates. PMID:24453510

Hendawy, Sherif F.; Raafat, TA

2011-01-01

18

An Earlier Uterine Environment Favors the In Vivo Development of Fresh Pig Morulae and Blastocysts Transferred by a Nonsurgical Deep-uterine Method  

PubMed Central

This study aimed to evaluate the effect of recipient-donor estrous cycle synchrony on recipient reproductive performance after nonsurgical deep-uterine (NsDU) embryo transfer (ET). The transfers (N=132) were conducted in recipients sows that started estrus 24 h before (–24 h; N=9) or 0 h (synchronous; N=31), 24 h (+24 h; N=74) or 48 h (+48 h; N=18) after the donors. A total of 30 day 5 morulae or day 6 blastocysts (day 0=onset of estrus) were transferred per recipient. The highest farrowing rates (FRs) were achieved when estrus appeared in recipients 24 h later than that in the donors (81.1%), regardless of the embryonic stage used for the transfers. The FR notably decreased (P<0.05) when recipients were –24 h asynchronous (0%), synchronous (61.3%) or +48 h asynchronous (50%) relative to the donors. No differences in litter size (LS) and piglet birth weights were observed among the synchronous and +24 h or +48 h asynchronous groups. While a +24 h asynchronous recipient was suitable for transfers performed with either morulae (FR, 74.3%; LS, 9.2 ± 0.6 piglets) or blastocysts (FR, 84.6%; LS, 9.8 ± 0.6 piglets), a + 48 h asynchronous recipient was adequate for blastocysts (FR, 87.5%; LS, 10.4 ± 0.7 piglets) but not for morulae (FR, 30.0%; LS, 7.3 ± 2.3 piglets). In conclusion, this study confirms the effectiveness of the NsDU-ET technology and shows that porcine embryos tolerate better a less advanced uterine environment if they are nonsurgically transferred deep into the uterine horn. PMID:25030061

ANGEL, Miguel Angel; GIL, Maria Antonia; CUELLO, Cristina; SANCHEZ-OSORIO, Jonatan; GOMIS, Jesus; PARRILLA, Inmaculada; VILA, Jordi; COLINA, Ignacio; DIAZ, Marta; REIXACH, Josep; VAZQUEZ, Jose Luis; VAZQUEZ, Juan Maria; ROCA, Jordi; MARTINEZ, Emilio A.

2014-01-01

19

Passage number of porcine embryonic germ cells affects epigenetic status and blastocyst rate following somatic cell nuclear transfer.  

PubMed

Epigenetic instability of donor cells due to long-term in vitro culture may influence the success rate of subsequent somatic cell nuclear transfer (SCNT). Therefore, the present study was designed (1) to investigate the epigenetic changes after prolonged culture in vitro of porcine embryonic germ (EG) cells, including differences in expression levels of both DNA methylation and demethylation-related genes and catalyses of histone modifications, and (2) to assess the efficiency of SCNT using EG cells from different passages. Results showed that genes either associated with DNA demethylation including DNMTs and TET1 or genes related to histone acetylation including HDACs were highly expressed in EG cells at higher passages when compared to EG cells at lower passages. In addition, the expression level of H3K27me3 functional methylase EZH2 increased while no changes were observed on H3K27me3 demethylase JMJD3 in relation to passage number. Moreover, the expression levels of both the H3K4me3 methylase MLL1 and the H3K4me3 demethylase RBP2 were increased at high passages. By using lower passage (numbers 3-5) EG cells as donor cells, the SCNT efficiency was significantly lower compared with use of fetal fibroblast donor cells. However, similar blastocyst rates were achieved when using higher passage (numbers 9-12) EG cells as donor cells. In conclusion, the present study suggests that the epigenetic status of EG cells change with increasing passage numbers, and that higher passage number EG cells are better primed for SCNT. PMID:24726409

Li, Juan; Gao, Yu; Petkov, Stoyan; Purup, Stig; Hyttel, Poul; Callesen, Henrik

2014-06-10

20

DNA microarray reveals that high proportions of human blastocysts from women of advanced maternal age are aneuploid and mosaic.  

PubMed

Trophectoderm (TE) biopsy and DNA microarray have become the new technologies for preimplantation genetic diagnosis in humans. In this study, we comprehensively examined aneuploid formation in human blastocysts produced in vitro with microarray and investigated the clinical outcome after transfer of euploid embryos. Biopsied cells from either TE or inner cell mass (ICM) were processed for microarray to examine the errors in 23 pairs of chromosomes and the consistency between TE and ICM. It was found that 56.6% of blastocysts were aneuploid. Further analysis indicated that 62.3% of aneuploid blastocysts had single and 37.7% had multiple chromosomal abnormalities. Chromosome errors could occur in any chromosome, but errors in chromosome 21 accounted for the most (11.3%) among the 23 pairs of chromosomes. Transfer of array-screened blastocysts produced high pregnancy (70.2%) and implantation (63.5%) rates. Microarray of TE and ICM cells in the same blastocysts revealed that high proportions of aneuploid blastocysts (69.2%) were mosaic, including aneuploid TE and euploid ICM, inconsistent anomalies between ICM and TE, or euploid TE cells and aneuploid ICM in the same blastocyst. These results indicate that high proportions of human blastocysts produced in vitro from women of advanced maternal age are aneuploid and mosaic. Errors can occur in any of the 23 pairs of chromosomes in human blastocysts. Biopsy from TE in blastocysts does not exactly predict the chromosomal information in ICM if the embryos are aneuploid. Some mosaic blastocysts have euploid ICM, which may indicate important differentiate mechanism(s) of human preimplantation embryos. PMID:23136294

Liu, Jianqiao; Wang, Weihua; Sun, Xiaofang; Liu, Lian; Jin, Hua; Li, Man; Witz, Craig; Williams, Dan; Griffith, Jason; Skorupski, Josh; Haddad, Gus; Gill, Jimmy

2012-06-01

21

Selection of competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing for patients undergoing preimplantation genetic screening: a prospective study with sibling oocytes  

PubMed Central

Background Recent advances in time-lapse monitoring in IVF treatment have provided new morphokinetic markers for embryonic competence. However, there is still very limited information about the relationship between morphokinetic parameters, chromosomal compositions and implantation potential. Accordingly, this study aimed at investigating the effects of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing on pregnancy and implantation outcomes for patients undergoing preimplantation genetic screening (PGS). Methods A total of 1163 metaphase II (MII) oocytes were retrieved from 138 PGS patients at a mean age of 36.6 ± 2.4 years. These sibling MII oocytes were then randomized into two groups after ICSI: 1) Group A, oocytes (n = 582) were cultured in the time-lapse system and 2) Group B, oocytes (n = 581) were cultured in the conventional incubator. For both groups, whole genomic amplification and array CGH testing were performed after trophectoderm biopsy on day 5. One to two euploid blastocysts within the most predictive morphokinetic parameters (Group A) or with the best morphological grade available (Group B) were selected for transfer to individual patients on day 6. Ongoing pregnancy and implantation rates were compared between the two groups. Results There were significant differences in clinical pregnancy rates between Group A and Group B (71.1% vs. 45.9%, respectively, p = 0.037). The observed implantation rate per embryo transfer significantly increased in Group A compared to Group B (66.2% vs. 42.4%, respectively, p = 0.011). Moreover, a significant increase in ongoing pregnancy rates was also observed in Group A compared to Group B (68.9% vs. 40.5%. respectively, p = 0.019). However, there was no significant difference in miscarriage rate between the time-lapse system and the conventional incubator (3.1% vs. 11.8%, respectively, p = 0.273). Conclusions This is the first prospective investigation using sibling oocytes to evaluate the efficiency of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing for PGS patients. Our data clearly demonstrate that the combination of these two advanced technologies to select competent blastocysts for transfer results in improved implantation and ongoing pregnancy rates for PGS patients. PMID:24954518

2014-01-01

22

Establishment of a bovine blastocyst-derived cell line collection for the comparative analysis of embryos created in vivo and by in vitro fertilization, somatic cell nuclear transfer, or parthenogenetic activation.  

PubMed

Tools and methods for analyzing differences in embryos resulting from somatic cell nuclear transfer (NT) in comparison to those derived from normal fertilization are needed to define better the nature of the nuclear reprogramming that occurs after NT. To this end, a collection of bovine blastocyst-derived cell lines was created. In vitro expanded or hatched blastocysts, used as primary culture tissue, were from NT; in vitro maturation, fertilization, and culture (IVF); or parthenogenetic (P) activation. Also, five in vivo-fertilized and developed blastocysts were collected by uterine flushing on the eighth d postfertilization. Whole blastocysts were physically attached to STO feeder layers to initiate all of the cell lines generated. The majority of the cell lines in the collection are trophectoderm, 38 NT-derived, 6 in vivo-derived, 20 IVF-derived, and 13 P-derived. Trophectoderm identity was ascertained by morphology and, in many cases, interferon-tau production. Several visceral endoderm cell lines and putative parietal endoderm cell lines were also established. At approximately 5% efficiency, epiblast masses from NT and IVF blastocysts survived and were isolated in culture. Two epiblast masses were also isolated from P blastocysts. Spontaneous differentiation from the epiblast outgrowths resulted in the establishment of fibroblast cell lines. The use of the trophectoderm cell lines as a comparative in vitro model of bovine trophectoderm and placental function is discussed in relation to NT reprogramming. PMID:17570020

Talbot, Neil C; Powell, Anne M; Camp, Mary; Ealy, Alan D

2007-02-01

23

ESTABLISHMENT OF A BOVINE BLASTOCYST-DERIVED CELL LINE COLLECTION FOR THE COMPARATIVE ANALYSIS OF EMBRYOS CREATED IN VIVO AND BY IN VITRO FERTILIZATION, SOMATIC CELL NUCLEAR TRANSFER, OR PARTHENOGENETIC ACTIVATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tools and methods for analyzing differences in embryos resulting from somatic cell nuclear transfer (NT) in comparison to those derived from normal fertilization are needed to better define the nature of the nuclear reprogramming that occurs after NT. To this end, a collection of bovine blastocyst...

24

Comparison between oral and vaginal estrogen usage in inadequate endometrial patients for frozen-thawed blastocysts transfer  

PubMed Central

Endometrial preparation with exogenous estrogen is a common practice in frozen-thawed embryo transfer (FET) cycles. The objective of this study was to compare the clinical outcomes of two endometrial preparation groups, oral estradiol valerate tablets (OEV) group versus vaginal estradiol (VE) tablets group, in inadequate endometrium patients. This retrospective, single-center, cohort study of patients undergoing FET treatment between Jan. 2012 and Jun. 2013, at an academic IVF center, included 247 patients (cycles) with endometrial thickness < 8 mm on day 13 of the hormone replacement cycle: OEV group included 69 patients (cycles) who received continuous OEV from day 1 onwards up to the day of progesterone supplement, while VE group included 178 patients (cycles) who taken OEV from day 1 to day 12, and used VE tablets from day 13 till the day of progesterone supplement. Patients in VE group required more days and higher dosage of estradiol, but had thinner endometrium on the day of transfer. However, the increase of endometrial thickness was more, when compared to OEV-treated patients. The implantation rate and pregnancy rate were, though not significantly, higher in VE group. Conclusions: Longer time of administration and higher dosage of estradiol usage did not have adverse effects on the clinical pregnancy rate. VE tablets may promote endometrial development and pregnancy success in FET cycles could not verify. Further study is needed to confirm the vaginal estradiol action on frozen-thawed embryo transfer cycles. PMID:25400786

Liao, Xiuhua; Li, Zhou; Dong, Xiyuan; Zhang, Hanwang

2014-01-01

25

Comparative Genomic Hybridization Selection of Blastocysts for Repeated Implantation Failure Treatment: A Pilot Study  

PubMed Central

The aim of this study is to determine if the use of preimplantation genetic screening (PGS) by array comparative genomic hybridization (array CGH) and transfer of a single euploid blastocyst in patients with repeated implantation failure (RIF) can improve clinical results. Three patient groups are compared: 43 couples with RIF for whom embryos were selected by array CGH (group RIF-PGS), 33 couples with the same history for whom array CGH was not performed (group RIF NO PGS), and 45 good prognosis infertile couples with array CGH selected embryos (group NO RIF PGS). A single euploid blastocyst was transferred in groups RIF-PGS and NO RIF PGS. Array CGH was not performed in group RIF NO PGS in which 1-2 blastocysts were transferred. One monoembryonic sac with heartbeat was found in 28 patients of group RIF PGS and 31 patients of group NO RIF PGS showing similar clinical pregnancy and implantation rates (68.3% and 70.5%, resp.). In contrast, an embryonic sac with heartbeat was only detected in 7 (21.2%) patients of group RIF NO PGS. In conclusion, PGS by array CGH with single euploid blastocyst transfer appears to be a successful strategy for patients with multiple failed IVF attempts. PMID:24779011

Greco, Ermanno; Bono, Sara; Ruberti, Alessandra; Lobascio, Anna Maria; Greco, Pierfrancesco; Biricik, Anil; Spizzichino, Letizia; Greco, Alessia; Tesarik, Jan; Minasi, Maria Giulia; Fiorentino, Francesco

2014-01-01

26

Live birth after blastocyst transfer following only 2 days of progesterone administration in an agonadal oocyte recipient.  

PubMed

In oocyte donation cycles where hormone replacement is given to recipients, progesterone administration is necessary to induce the luteal phase and synchronize the endometrium with the embryo stage. Most studies suggest that 5-7 days of progesterone are needed to prepare the endometrium for a day-5 embryo transfer and provide optimal implantation rate. This paper reports a case where an agonadal oocyte recipient received only 2 days of progesterone prior to the embryo transfer of a day-5 embryo. She subsequently had a clinical pregnancy and a live birth. PMID:22868081

Theodorou, Efstathios; Forman, Robert

2012-10-01

27

Effect of knockout serum replacement supplementation to culture medium on porcine blastocyst development and piglet production.  

PubMed

We have previously developed chemically defined media suitable for in vitro production (IVP) of porcine embryos and subsequently generated piglets by nonsurgical embryo transfer. In this study, to further improve the culture conditions for IVP of porcine embryos, we evaluated the effect of knockout serum replacement (KSR), a substitute for serum or albumin, on the viability and development of porcine blastocysts. The addition of 5% (v:v) KSR to porcine blastocyst medium (PBM) on Day 5 (Day 0 = IVF) significantly increased the survival and hatching rates of blastocysts and the total cell number of Day-7 blastocysts compared with those in cultures without KSR or addition of 10% fetal bovine serum. Furthermore, the number of cells in the trophectoderm of Day-6 blastocysts and the ATP content of Day-7 blastocysts cultured with 5% KSR were significantly higher than those of blastocysts cultured without KSR. The mRNA expression of a rate-limiting enzyme in ?-oxidation, carnitine palmitoyltransferase 1, in Day-6 blastocysts, and a serine proteinase, urokinase-type plasminogen activator, in Day-7 blastocysts cultured in 5% KSR-PBM was significantly higher than that of blastocysts cultured in PBM alone. Four of eight recipients (50%), in which Day-5 blastocysts treated with 5% KSR were transferred nonsurgically, became pregnant. However, the efficiency of piglet production (percentage of piglets born based on the number of embryos transferred) was similar to recipients with transferred blastocysts treated without KSR. The present study demonstrated that the addition of KSR to PBM enhanced the in vitro viability of porcine blastocysts. In addition, our data suggest that KSR improved development to the hatching stage and blastocyst quality by increasing ATP content and hatching-related mRNA expression of blastocysts. PMID:25434774

Sakurai, Masahiro; Suzuki, Chie; Yoshioka, Koji

2015-03-01

28

Blastocyst culture and cryopreservation to optimize clinical outcomes of warming cycles.  

PubMed

Surplus embryos available for cryopreservation in fresh cycles are considered as having good potential for future use. However, the optimal stage of embryo cryopreservation remains unclear. In this study, 1190 patients with surplus embryos on day 3 were divided into two groups: cleavage-stage embryo cryopreservation (control group) and blastocyst cryopreservation (blastocyst group). The clinical outcomes of the subsequent warming cycles were evaluated. The proportion of cycles with blastocyst formation was 73.8% in the blastocyst group. Although in the blastocyst group, the cancellation rate of blastocyst transfer was increased due to lack of blastocysts available for cryopreservation, the blastocyst group achieved significantly higher rates of clinical pregnancy/cycle (43.2% versus 34.9%; P=0.003), pregnancy/transfer (59.5% versus 35.4%; P<0.001) and implantation (46.5% versus 22.2%; P<0.001) from the first warming cycle compared with the control group. In an embryo-number classified analysis, the clinical pregnancy rate was also higher in the blastocyst group. However, the cumulative pregnancy was similar between the two groups. Blastocyst culture as an embryo selection tool will not improve embryo viability but it will help patients to achieve pregnancy more quickly. Extended culture of surplus embryos to the blastocyst stage for cryopreservation optimizes the clinical outcomes. PMID:23769665

Zhu, Lixia; Xi, Qingsong; Zhang, Hanwang; Li, Yufeng; Ai, Jihui; Jin, Lei

2013-08-01

29

The Effects of 5-Aza-2?- Deoxycytidine and Trichostatin A on Gene Expression and DNA Methylation Status in Cloned Bovine Blastocysts  

PubMed Central

Abstract We previously found that treatment of both donor cells and early cloned embryos with combination of 5-aza-2?-deoxycytidine (5-aza-dC) and trichostatin A (TSA) significantly improve the in vitro and full-term development of nuclear transfer (NT) bovine embryos. To investigate how this treatment improved the epigenetic reprogramming of somatic cell nuclei, we compared the expression levels of DNA methylation-, chromatin structure-, and development-related genes in in vitro fertilized (IVF group), NT (C-NT group), and 5-aza-dC and TSA-treated NT (T-NT group) single blastocyst using quantitative real-time PCR. We also compared the DNA methylation status of satellite I among three groups using bisulfite sequencing analysis and combined bisulfite restriction analysis (COBRA). There were significantly lower levels of DNMT1, DNMT3b, HDAC2, and IGF2 transcripts in T-NT blastocysts than in C-NT blastocysts, whereas the relative abundance of OCT4 and SOX2 mRNA was significantly increased in T-NT blastocysts compared to C-NT blastocysts. In addition, the treatment also reduced the DNA methylation levels of NT blastocysts on satellite I sequence. It is likely that TSA may act synergistically with 5-aza-dC to exert such modifications in gene expression and DNA methylation, subsequently enhancing developmental potential (in vitro and full-term) of treated cloned embryos. PMID:21486115

Wang, Yongsheng; Su, Jianmin; Wang, Lijun; Xu, Wenbing; Quan, Fusheng; Liu, Jun

2011-01-01

30

Utility of FT-IR imaging spectroscopy in estimating differences between the quality of bovine blastocysts  

NASA Astrophysics Data System (ADS)

This study was conducted to verify whether the FT-IR spectroscopy and Focal Plane Array (FPA) imaging can be successfully applied to estimate the quality of bovine blastocysts (on the basis of the concentration of nucleic acids and amides). The FT-IR spectra of inner cell mass from blastocysts of three different culture systems were examined. The spectral changes between blastocysts were analyzed in DNA (spectral range of 1240-950 cm-1) and protein amides (1800-1400 cm-1). Blastocyst 1 (BL1-HA) was developed from the fertilized oocyte cultured with low concentration of hialuronian (HA), Blastocyst 2 and 3 were developed from the oocytes cultured in standard conditions. Cleavage stage blastocyst 2 (BL2-SOF) has been cultured in SOF medium while blastocyst 3 (BL3-VERO) was cultured in co-culture with VERO cells. The multivariate statistical analysis (Hierarchical Cluster Analysis - HCA and Principal Component Analysis - PCA) of single cells spectra showed high similarity of cells forming the inner cell mass within single blastocyst. The main variance between the three examined blastocysts was related to amides bands. Differences in the intensities of the amides' peaks between the bovine blastocysts derived from different culture systems indicated that specific proteins reflecting the appearance of a new phenotype were produced. However, for the three blastocysts, the ?-helix typical peak was twice more intensive than the ?-sheet typical peak suggesting that the differentiation processes had been started. Taking into account the quantitative and qualitative composition of the protein into examined blastocysts, it can be assumed, that the quality of the BL1-HA turned out much more similar to BL3-VERO than to BL2-SOF. FT-IR spectroscopy can be successfully applied in reproductive biology research for quality estimation of oocytes and embryos at varied stages of their development. Moreover this technique proved to be particularly useful when the quantity of the available material for research purposes is limited.

Wieche?, A.; Opiela, J.; Lipiec, E.; Kwiatek, W. M.

2013-10-01

31

Live birth after single embryo transfer of autologous cryopreserved oocytes from a patient with myelodysplastic syndrome who underwent allogenic peripheral blood stem cell transplantation.  

PubMed

We report a live birth after single embryo transfer derived from autologous cryopreserved oocytes of a patient with myelodysplastic syndrome who had undergone allogenic peripheral blood stem cell transplantation (PBSCT). In 2006, a 24-year-old female diagnosed with myelodysplastic syndrome was referred for fertility preservation before she underwent PBSCT. After controlled ovarian stimulation, 38 oocytes were retrieved for cryopreservation using a slow-freezing protocol. She was cured by PBSCT and entered menopause. After seven years, she requested thawing of the oocytes. She was prepared for a thawing cycle using hormone replacement therapy. Twenty-two cryopreserved oocytes were thawed, and 20 (91%) oocytes survived. Thirteen mature oocytes were inseminated by intracytoplasmic sperm injection. Ten (77%) oocytes were normally fertilized and 6 (60%) oocytes developed into blastocysts. Embryo transfer to her own uterus with one blastocyst was performed. Five blastocysts were vitrified. A sonographic exam at 7 weeks of gestation revealed one gestational sac with positive cardiac motion. A normal female baby weighing 2704 g was delivered at 40 weeks of gestation. A successful pregnancy from autologous cryopreserved oocytes is encouraging for cancer patients undergoing fertility preservation. For infertile cancer patients after PBSCT, we suggest the transfer of one embryo to reduce the risk of multiple pregnancies. PMID:25294099

Tsai, Yi-Yi; Chen, Shee-Uan; Shieh, Chia-Jen; Yao, Yi-Lin; Yang, Yu-Shih; Chen, Chin-Der

2014-12-01

32

Maternal and Genetic Effects on the Acoustic Startle Reflex and its Sensitization in C3H\\/HeN, DBA\\/2JHd and NMRI Mice Following Blastocyst Transfer  

Microsoft Academic Search

In the present study, reciprocal embryo transfers were conducted to examine genetic and maternal effects on the baseline and\\u000a fear-sensitized acoustic startle response (ASR) in the two inbred strains C3H\\/HeN and DBA\\/2JHd and the outbred strain NMRI.\\u000a The largest differences in the ASR were found in untreated strains (effect size 0.6). The transfer procedure per se had a\\u000a significant effect

Claudia Rose; Friedrich-Wilhelm Röhl; Joachim Hanke; Herbert Schwegler; Deniz M. Yilmazer-Hanke

2008-01-01

33

Single Molecule Spectroscopy of Electron Transfer  

SciTech Connect

The objectives of this research are threefold: (1) to develop methods for the study electron transfer processes at the single molecule level, (2) to develop a series of modifiable and structurally well defined molecular and nanoparticle systems suitable for detailed single molecule/particle and bulk spectroscopic investigation, (3) to relate experiment to theory in order to elucidate the dependence of electron transfer processes on molecular and electronic structure, coupling and reorganization energies. We have begun the systematic development of single molecule spectroscopy (SMS) of electron transfer and summaries of recent studies are shown. There is a tremendous need for experiments designed to probe the discrete electronic and molecular dynamic fluctuations of single molecules near electrodes and at nanoparticle surfaces. Single molecule spectroscopy (SMS) has emerged as a powerful method to measure properties of individual molecules which would normally be obscured in ensemble-averaged measurement. Fluctuations in the fluorescence time trajectories contain detailed molecular level statistical and dynamical information of the system. The full distribution of a molecular property is revealed in the stochastic fluctuations, giving information about the range of possible behaviors that lead to the ensemble average. In the case of electron transfer, this level of understanding is particularly important to the field of molecular and nanoscale electronics: from a device-design standpoint, understanding and controlling this picture of the overall range of possible behaviors will likely prove to be as important as designing ia the ideal behavior of any given molecule.

Michael Holman; Ling Zang; Ruchuan Liu; David M. Adams

2009-10-20

34

Identification of Inappropriately Reprogrammed Genes by Large-Scale Transcriptome Analysis of Individual Cloned Mouse Blastocysts  

PubMed Central

Although cloned embryos generated by somatic/embryonic stem cell nuclear transfer (SECNT) certainly give rise to viable individuals, they can often undergo embryonic arrest at any stage of embryogenesis, leading to diverse morphological abnormalities. In an effort to gain further insights into reprogramming and the properties of SECNT embryos, we performed a large-scale gene expression profiling of 87 single blastocysts using GeneChip microarrays. Sertoli cells, cumulus cells, and embryonic stem cells were used as donor cells. The gene expression profiles of 87 blastocysts were subjected to microarray analysis. Using principal component analysis and hierarchical clustering, the gene expression profiles were clearly classified into 3 clusters corresponding to the type of donor cell. The results revealed that each type of SECNT embryo had a unique gene expression profile that was strictly dependent upon the type of donor cells, although there was considerable variation among the individual profiles within each group. This suggests that the reprogramming process is distinct for embryos cloned from different types of donor cells. Furthermore, on the basis of the results of comparison analysis, we identified 35 genes that were inappropriately reprogrammed in most of the SECNT embryos; our findings demonstrated that some of these genes, such as Asz1, Xlr3a and App, were appropriately reprogrammed only in the embryos with a transcriptional profile that was the closest to that of the controls. Our findings provide a framework to further understand the reprogramming in SECNT embryos. PMID:20614022

Morita, Shinnosuke; Yamada, Kaori; Jincho, Yuko; Tane, Shouji; Sotomaru, Yusuke; Kono, Tomohiro

2010-01-01

35

Successful production of piglets derived from expanded blastocysts vitrified using a micro volume air cooling method without direct exposure to liquid nitrogen.  

PubMed

This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN?). Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol, 0.6 M trehalose and 2% (wt/vol) polyethylene glycol in 10% HEPES-buffered PZM-5. The blastocysts were collected from gilts and vitrified using the new device (MVAC) or a Cryotop (CT). Blastocysts were stored in LN? for at least 1 month. After warming, cryoprotective agents were removed using a single step. Survival of the embryos was assessed by in vitro culture (Experiment 1) and by embryo transfer to recipients (Experiment 2). In Experiment 1, the embryos vitrified by the MVAC or CT and fresh embryos without vitrification (Control) were used. The survival rates of embryos in the MVAC, CT and Control groups were 88.9% (32/36), 91.7% (33/36) and 100% (34/34), respectively, after 48 h culture, and the hatching rates of embryos after 48 h incubation were 69.4% (25/36), 63.9% (23/36) and 94.1% (32/34), respectively. In Experiment 2, 64 vitrified embryos were transferred to 5 recipient gilts, and 8 healthy piglets were produced from 3 recipients in the MVAC group. Similarly, 66 vitrified embryos were transferred to 5 recipient gilts, and 9 healthy piglets were produced from 2 recipients in the CT group. These results indicated that porcine expanded blastocysts can be cryopreserved using the MVAC method without potential pathogen contamination from LN?. PMID:23955236

Misumi, Koji; Hirayama, Yuri; Egawa, Sachiko; Yamashita, Shoko; Hoshi, Hiroyoshi; Imai, Kei

2013-12-17

36

Successful Production of Piglets Derived from Expanded Blastocysts Vitrified Using a Micro Volume Air Cooling Method without Direct Exposure to Liquid Nitrogen  

PubMed Central

Abstract This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN2). Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol, 0.6 M trehalose and 2% (wt/vol) polyethylene glycol in 10% HEPES-buffered PZM-5. The blastocysts were collected from gilts and vitrified using the new device (MVAC) or a Cryotop (CT). Blastocysts were stored in LN2 for at least 1 month. After warming, cryoprotective agents were removed using a single step. Survival of the embryos was assessed by in vitro culture (Experiment 1) and by embryo transfer to recipients (Experiment 2). In Experiment 1, the embryos vitrified by the MVAC or CT and fresh embryos without vitrification (Control) were used. The survival rates of embryos in the MVAC, CT and Control groups were 88.9% (32/36), 91.7% (33/36) and 100% (34/34), respectively, after 48 h culture, and the hatching rates of embryos after 48 h incubation were 69.4% (25/36), 63.9% (23/36) and 94.1% (32/34), respectively. In Experiment 2, 64 vitrified embryos were transferred to 5 recipient gilts, and 8 healthy piglets were produced from 3 recipients in the MVAC group. Similarly, 66 vitrified embryos were transferred to 5 recipient gilts, and 9 healthy piglets were produced from 2 recipients in the CT group. These results indicated that porcine expanded blastocysts can be cryopreserved using the MVAC method without potential pathogen contamination from LN2. PMID:23955236

MISUMI, Koji; HIRAYAMA, Yuri; EGAWA, Sachiko; YAMASHITA, Shoko; HOSHI, Hiroyoshi; IMAI, Kei

2013-01-01

37

Vitrification of zona-free rabbit expanded or hatching blastocysts: a possible model for human blastocysts  

Microsoft Academic Search

BACKGROUND: The purpose of this study was to test the effectiveness of one two-step (A) and two one-step (B1 and B2) vitrification procedures on denuded expanded or hatching rabbit blastocysts held in standard sealed plastic straws as a possible model for human blastocysts. The effect of blastocyst size was also studied on the basis of three size categories (I: diameter

R. P. Cervera; F. Garcia-Ximenez

2003-01-01

38

Forced collapse of the blastocoel cavity improves developmental potential in cryopreserved bovine blastocysts by slow-rate freezing and vitrification.  

PubMed

This study was conducted to evaluate the effectiveness of forced collapse of the blastocoel before slow-rate freezing and vitrification of bovine blastocysts. Cryopreservation of bovine blastocysts has been proposed as a tool to improve the feasibility of cattle production using the embryo transfer technique. However, the low efficiency of frozen-thawed embryos survival and further development is a crucial problem. In this study, bovine in vitro and in vivo blastocysts were slow-rate frozen and vitrified after forced blastocoele collapse (FBC) of the blastocyst cavity by puncturing the blastocoele with a pulled Pasteur pipet. Differences in the developmental potential of frozen-thawed blastocysts derived from FBC and non-FBC groups were found in both slow-rate freezing and vitrification. Furthermore, we found that the total cell number of blastocysts in FBC groups was increased and the index of apoptosis in FBC groups was decreased. Consistent with these results, real-time RT-PCR analysis data showed that expression of the anti-apoptotic Bcl-XL gene was significantly increased by FBC groups, whereas expression of the pro-apoptotic Bax gene was significantly decreased by FBC groups. Our results also showed that pregnancy outcomes in both slow-rate frozen and vitrified bovine in vivo blastocysts could be improved by reducing the fluid content after FBC of the blastocyst cavity. Therefore, we suggest that FBC of the blastocyst cavity with a pulled Pasteur pipet is an effective pre-treatment technique for both slow-rate freezing and vitrification of bovine blastocysts. PMID:24942049

Min, S-H; Kim, J-W; Lee, Y-H; Park, S-Y; Jeong, P-S; Yeon, J-Y; Park, H; Chang, K-T; Koo, D-B

2014-08-01

39

Cytotoxic Effects of Dillapiole on Embryonic Development of Mouse Blastocysts in Vitro and in Vivo  

PubMed Central

We examined the cytotoxic effects of dillapiole, a phenylpropanoid with antileishmanial, anti-inflammatory, antifungal, and acaricidal activities, on the blastocyst stage of mouse embryos, subsequent embryonic attachment and outgrowth in vitro, and in vivo implantation via embryo transfer. Blastocysts treated with 2.5–10 ?M dillapiole exhibited a significant increase in apoptosis and corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with dillapiole were lower than those of their control counterparts. Moreover, in vitro treatment with 2.5–10 ?M dillapiole was associated with increased resorption of post-implantation embryos and decreased fetal weight. Our results collectively indicate that dillapiole induces apoptosis and retards early post-implantation development, both in vitro and in vivo. However, the extent to which this organic compound exerts teratogenic effects on early human development is not known at present. Further studies are required to establish effective protection strategies against the cytotoxic effects of dillapiole. PMID:24933639

Chan, Wen-Hsiung

2014-01-01

40

Single Molecule Electron Transfer Process of Ruthenium Complexes.  

SciTech Connect

Transition metal complexes such as ruthenium complexes, having metal-to-ligand charge transfer states, are extensively used in solar energy conversion and electron transfer in biological systems and at interfaces. The dynamics of metal-to-ligand charge transfer and subsequent intermolecular, intramolecular, and interfacial electron transfer processes can be highly complex and inhomogeneous, especially when molecules are involved in interactions and perturbations from heterogeneous local environments and gated by conformation fluctuations. We have employed the single-molecule spectroscopy, a powerful approach for inhomogeneous systems to study the electron transfer dynamics of ruthenium complexes. We have applied a range of statistical analysis methods to reveal nonclassical photon emission behavior of the single ruthenium complex, i.e., photon antibunching, and photophysical ground-state recovering dynamics on a microsecond time scale. The use of photon antibunching to measure phosphorescence lifetimes and single-molecule electron transfer dynamics at room temperature is demonstrated.

Hu, Dehong; Lu, H PETER.

2006-03-01

41

Microtube liquid single-phase heat transfer in laminar flow  

Microsoft Academic Search

One of the main applications of microscale flow is miniature, high-efficiency heat transfer. The most simple and immediate solution to the problem of concentrated heat exchange is the use of small diameter channels with single-phase water flow, but there is a lack of publicised knowledge about the heat transfer performance in these conditions. In this article, an experimental investigation is

G. P. Celata; M. Cumo; V. Marconi; S. J. McPhail; G. Zummo

2006-01-01

42

Protein Conformational Dynamics Probed by Single-Molecule Electron Transfer  

Microsoft Academic Search

Electron transfer is used as a probe for angstrom-scale structural changes in single protein molecules. In a flavin reductase, the fluorescence of flavin is quenched by a nearby tyrosine residue by means of photo-induced electron transfer. By probing the fluorescence lifetime of the single flavin on a photon-by-photon basis, we were able to observe the variation of flavin-tyrosine distance over

Haw Yang; Guobin Luo; Pallop Karnchanaphanurach; Tai-Man Louie; Ivan Rech; Sergio Cova; Luying Xun; X. Sunney Xie

2003-01-01

43

Establishing three blastocyst lineages--then what?  

PubMed

Development of the mouse embryo to the blastocyst stage occurs over 3 to 4 days following fertilization of the oocyte. During this time, several molecular and morphological events take place that result in the formation of three distinct cell lineages: the trophectoderm, the epiblast, and the primitive endoderm. Many studies have investigated the processes that control lineage specification in the blastocyst including gene expression, cell signaling, cell-cell contact/positional relationships, and most recently, epigenetics. Here we review, at the molecular level, recent contributions to our understanding of the mechanisms that play a role in formation of these lineages. Additionally, we focus on the next steps in differentiation to highlight processes important in the development of those lineages that contribute to the extraembryonic tissues. In this context, we discuss the establishment of extraembryonic ectoderm and the contributions of parietal and visceral endoderm to yolk sac formation. PMID:21123814

Gasperowicz, Malgorzata; Natale, David R C

2011-04-01

44

Oxamflatin Significantly Improves Nuclear Reprogramming, Blastocyst Quality, and In Vitro Development of Bovine SCNT Embryos  

PubMed Central

Aberrant epigenetic nuclear reprogramming results in low somatic cloning efficiency. Altering epigenetic status by applying histone deacetylase inhibitors (HDACi) enhances developmental potential of somatic cell nuclear transfer (SCNT) embryos. The present study was carried out to examine the effects of Oxamflatin, a novel HDACi, on the nuclear reprogramming and development of bovine SCNT embryos in vitro. We found that Oxamflatin modified the acetylation status on H3K9 and H3K18, increased total and inner cell mass (ICM) cell numbers and the ratio of ICM?trophectoderm (TE) cells, reduced the rate of apoptosis in SCNT blastocysts, and significantly enhanced the development of bovine SCNT embryos in vitro. Furthermore, Oxamflatin treatment suppressed expression of the pro-apoptotic gene Bax and stimulated expression of the anti-apoptotic gene Bcl-XL and the pluripotency-related genes OCT4 and SOX2 in SCNT blastocysts. Additionally, the treatment also reduced the DNA methylation level of satellite I in SCNT blastocysts. In conclusion, Oxamflatin modifies epigenetic status and gene expression, increases blastocyst quality, and subsequently enhances the nuclear reprogramming and developmental potential of SCNT embryos. PMID:21912607

Li, Yanyan; Li, Ruizhe; Li, Qian; Wu, Yongyan; Quan, Fusheng; Liu, Jun; Guo, Zekun; Zhang, Yong

2011-01-01

45

Probing the interaction between two single molecules: fluorescence resonance energy transfer between a single donor and a single acceptor.  

PubMed Central

We extend the sensitivity of fluorescence resonance energy transfer (FRET) to the single molecule level by measuring energy transfer between a single donor fluorophore and a single acceptor fluorophore. Near-field scanning optical microscopy (NSOM) is used to obtain simultaneous dual color images and emission spectra from donor and acceptor fluorophores linked by a short DNA molecule. Photodestruction dynamics of the donor or acceptor are used to determine the presence and efficiency of energy transfer. The classical equations used to measure energy transfer on ensembles of fluorophores are modified for single-molecule measurements. In contrast to ensemble measurements, dynamic events on a molecular scale are observable in single pair FRET measurements because they are not canceled out by random averaging. Monitoring conformational changes, such as rotations and distance changes on a nanometer scale, within single biological macromolecules, may be possible with single pair FRET. Images Fig. 2 Fig. 4 PMID:8692803

Ha, T; Enderle, T; Ogletree, D F; Chemla, D S; Selvin, P R; Weiss, S

1996-01-01

46

Blastocyst rate of in vitro embryo production in sheep is affected by season.  

PubMed

It has been reported that the number and quality of in vitro produced embryos is season related. This study was conducted to assess the effect of season on cleavage, blastocyst and lambing rates of in vitro produced ovine embryos during 3 years of collection data. Ovaries of Sarda sheep were collected from a slaughterhouse. In total, 5035 oocytes were recovered and matured in TCM-199 with 4 mg/ml bovine serum albumin (BSA), 100 ?M cysteamine, 0.3 mM Na pyruvate, 0.1 UI/ml recombinant follicle-stimulating hormone (r-FSH), 0.1 UI/ml recombinant luteinising hormone (r-LH), and 1 ?g/ml estradiol-17?. Matured oocytes were fertilized with fresh semen in synthetic oviductal fluid (SOF) with 20% heat inactivated estrous sheep serum. The presumptive zygotes were cultured for 6-7 days (blastocyst stage) in SOF medium supplemented with 1% Basel Medium Eagle (BME), 1% Minimum Essential Medium, 1 mM glutamine and 8 mg/ml fatty acid-free BSA. The embryos produced were vitrified and a total of 165 blastocysts (80 from the breeding season and 85 from the anoestrous season) were transferred in pairs into recipient ewes during the reproductive period. There were no significant differences in cleavage rates between seasons in any of the 3 years examined (84% versus 83%, 81% versus 80% and 80% versus 79%, respectively). The blastocyst rate varied significantly between seasons in 2005 and 2007 (P < 0.05), and in 2006 (P < 0.001). There were no differences in pregnancy and lambing rates between embryos during anoestrous versus during the breeding season. In conclusion, only the blastocyst rate appeared to have been affected by season, possibly due to variation in the number of developmentally competent oocytes. PMID:23458093

Mara, L; Sanna, D; Casu, S; Dattena, M; Muñoz, I M Mayorga

2014-08-01

47

Correlated Single Quantum Dot Blinking and Interfacial Electron Transfer Dynamics  

PubMed Central

The electron transfer (ET) dynamics from core/multi-shell (CdSe/CdS3MLZnCdS2MLZnS2ML) quantum dots (QDs) to adsorbed Fluorescein (F27) molecules have been studied by single particle spectroscopy to probe the relationship between single QD interfacial electron transfer and blinking dynamics. Electron transfer from the QD to F27 and the subsequent recombination were directly observed by ensemble-averaged transient absorption spectroscopy. Single QD-F27 complexes show correlated fluctuation of fluorescence intensity and lifetime, similar to those observed in free QDs. With increasing ET rate (controlled by F27-to-QD ratio), the lifetime of on states decreases and relative contribution of off states increases. It was shown that ET is active for QDs in on states, the excited state lifetime of which reflects the ET rate, whereas in the off state QD excitons decay by Auger relaxation and ET is not a competitive quenching pathway. Thus, the blinking dynamics of single QDs modulate their interfacial ET activity. Furthermore, interfacial ET provides an additional pathway for generating off states, leading to correlated single QD interfacial ET and blinking dynamics in QD-acceptor complexes. Because blinking is a general phenomenon of single QDs, it appears that the correlated interfacial ET and blinking and the resulting intermittent ET activity are general phenomena for single QDs. PMID:21915369

Jin, Shengye; Hsiang, Jung-Cheng; Zhu, Haiming; Song, Nianhui; Dickson, Robert M.; Lian, Tianquan

2011-01-01

48

Expression of mRNA, before and after freezing, in bovine blastocysts cultured under different conditions.  

PubMed

Production methods and culture systems have been shown to affect blastocyst mRNA expression and cryopreservability, which may serve as sensitive indicators of embryo quality and developmental competence. In the present study, the impact of four established culture conditions for producing bovine blastocysts (in vitro production, IVP; gamete intra-fallopian transfer, GIFT; transfer of cleaved stages into the oviduct, CLVT; multiple ovulation embryo transfer, MOET) was assessed, in terms of both cryosurvival and levels of mRNA expression of several selected genes (occludin, desmocollin 2, solute carrier family 2 member 3, BAX, BCL-XL, heat shock protein 1A, aquaporin 3, DNA methyltransferase 1a) detected with RT-qPCR. At 24 hours post-thawing, blastocysts derived from in vitro production showed a significantly higher re-expansion rate compared to the other groups. At later times, this difference was no longer significant. Before freezing, embryos of the MOET group showed significantly more desmocollin 2 mRNA compared to embryos produced using other culture methods. After freezing, significant upregulation was found in transcripts of heat shock protein 1A in embryos of all groups; of solute carrier family 2 member 3, only in IVP derived embryos; of BAX, BCL-XL, occludin, desmocollin 2, only in the MOET and IVP groups. Aquaporin 3 and DNA methyltransferase 1a were neither up- nor downregulated in blastocysts of any group. In conclusion, these findings suggest that, after freezing, embryos seem to have switched on mRNA synthesis, an active metabolism, operational cell connections, and are prepared for hatching and beyond. PMID:21144573

Kuzmany, Anna; Havlicek, Vitezslav; Wrenzycki, Christine; Wilkening, Sandra; Brem, Gottfried; Besenfelder, Urban

2011-02-01

49

Technique of Coronary Transfer for TGA with Single Coronary Artery  

PubMed Central

An eight-day-old neonate was diagnosed with dextro-transposition of the great arteries, atrial septal defect, patent ductus arteriosus, and a single sinus origin of the coronary arteries. The single coronary artery originated from the left sinus (sinus 2), had a proximal left circumflex arterial branch, and passed anteriorly to the right side of the aorta, further branching into the right coronary and left anterior descending arteries. We successfully performed an arterial switch operation and coronary transfer by tube graft reconstruction with autologous aortic tissue to treat the dextro-transposition of the great arteries and atrial septal defect with a single-sinus origin of the coronary arteries.

Kim, Tae Ho; Jung, Jae Jun; Kim, Yong Han; Yang, Ji-Hyuk; Jun, Tae-Gook

2014-01-01

50

Spin-transfer torque in a single ferromagnet  

NASA Astrophysics Data System (ADS)

A spin polarized current, with sufficiently high current density, is able to switch a magnet or induce magnetization precession. This is the consequence of the ¡°spin-transfer torque¡+/- that originates from spin angular momentum transfer between conduction electrons and the magnetization. Previously most theories and experiments explore F/N/F trilayer and F/N multilayer structures, where F denotes a ferromagnet and N denotes a nonmagnetic metal. These structures have been generally presumed indispensable, since non-collinear magnetizations between a polarizing layer and a free layer are required to generate spin torques, and the GMR effect is essential in detecting magnetization variations. In this work, spin-transfer torque effects in a single ferromagnetic layer are demonstrated, using current injection through a point-contact at 4.2 K. Firstly, differential resistance peaks, generally regarded as signatures of spin-wave excitations, are observed in a single ferromagnetic layer in high magnetic fields [1]. The current values corresponding to the peak positions linearly depend on the external field in the range of 2 to 9 Tesla. Secondly, hysteretic current-induced switching is observed in a single ferromagnet in low magnetic fields. Both experiments can be interpreted by a simple model based on heterogeneous current distribution and domain wall scattering. Systematic variations between low field and high field regions have been investigated and the implications will be discussed. [1] Y. Ji, C. L. Chien and M. D. Stiles, Phys. Rev. Lett. 90, 106601 (2003)

Ji, Yi

2004-03-01

51

Single and multistep energy transfer processes within doped polymer nanoparticles.  

PubMed

Herein, we demonstrate the design of multiple fluorophores Coumarin 153 (C153) and Nile Red (NR) encapsulated in semiconducting poly[N-vinylcarbazole] (PVK) polymer nanoparticles (50-70 nm in diameter) by a simple re-precipitation technique, and elucidate their photophysical properties by steady-state and picosecond (ps) time resolved emission spectroscopy. It is interesting to note that multistep cascaded energy transfer occurs from the excited host PVK molecules to NR dye molecules through C153. The energy transfer time constants are found to be 180 ps for PVK?C153, 360 ps for PVK?NR, and 140 ps for the overall energy transfer process from PVK to NR through C153 dye molecules. The multistep energy transfer allows tuning of the wide range emission from 350 nm to 700 nm by changing the relative concentrations of the encapsulated dye molecules. Bright, stable, and white light emission of the dye doped polymer nanoparticles with a quantum yield of 14% is achieved at a particular concentration ratio of the C153?: NR dye. The generation of "cool" white emission in suspension and in the solid state film opens up new possibilities to obtain white light OLEDs based on single nanoparticles. PMID:24969364

Martin, Cristina; Bhattacharyya, Santanu; Patra, Amitava; Douhal, Abderrazzak

2014-09-01

52

Mouse embryo development in vitro: effects of inhibitors of RNA and protein synthesis on blastocyst and post-blastocyst embryos.  

PubMed

The effect of inhibitors of RNA synthesis (Cordycepin, Actinomycin D) and protein synthesis (Cycloheximide) on the development and growth of mouse blastocysts in vitro was explored. Blastocysts exposed in vitro for 24 hours to 50 mu-g/ml Cordycepin, 0.005 mu-g/ml Actinomycin D, or 0.1 mu-g/ml Cycloheximde grew and began to attach to the dish in the similar manner as did the controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Control blastocysts grown in vitro for six days attached to the dish, trophoblastic layer was spread and inner cell mass continued to grow and formed an egg-cylinder like structure. Blastocysts grown in constant presence of 50 mu-g/ml of Cordycepin in themedium or those exposed to inhibitor only for the first 24 hours failed to develop inner cell mass derivatives in culture, although the growth of trophoblastic cells was as in controls. The same results were obtained if blastocysts were exposed to 0.005 mu-g/ml of Actinomycin D or to 0.1 mu-g/ml of Cycloheximide either continuously or for the first 24 hours. Higher concentrations of Actinomycin D (0.05 mu-g/ml) or Cycloheximde (1 mu-g/ml) were toxic for the blastocysts causing their degeneration within 24-48 hours. Our results suggested that appropriate concentrations of RNA or protein synthesis inhibitors could prevent the development of inner cell mass derivatives with essentially no effect on the development of primary trophoblast. This would indicate that the process of differentiation of inner cell mass cells is much more sensitive to metabolic inhibitors than the differentiation of giant trophoblastic cells. PMID:1079529

Rowinski, J; Solter, D; Koprowski, H

1975-05-01

53

The Prevalence of Chromosomal Deletions Relating to Developmental Delay and/or Intellectual Disability in Human Euploid Blastocysts  

PubMed Central

Chromosomal anomalies in human embryos produced by in vitro fertilization are very common, which include numerical (aneuploidy) and structural (deletion, duplication or others) anomalies. Our previous study indicated that chromosomal deletion(s) is the most common structural anomaly accounting for approximately 8% of euploid blastocysts. It is still unknown if these deletions in human euploid blastocysts have clinical significance. In this study, we analyzed 15 previously diagnosed euploid blastocysts that had chromosomal deletion(s) using Agilent oligonucleotide DNA microarray platform and localized the gene location in each deletion. Then, we used OMIM gene map and phenotype database to investigate if these deletions are related with some important genes that cause genetic diseases, especially developmental delay or intellectual disability. As results, we found that the detectable chromosomal deletion size with Agilent microarray is above 2.38 Mb, while the deletions observed in human blastocysts are between 11.6 to 103 Mb. With OMIM gene map and phenotype database information, we found that deletions can result in loss of 81-464 genes. Out of these genes, 34–149 genes are related with known genetic problems. Furthermore, we found that 5 out of 15 samples lost genes in the deleted region, which were related to developmental delay and/or intellectual disability. In conclusion, our data indicates that all human euploid blastocysts with chromosomal deletion(s) are abnormal and transfer of these embryos may cause birth defects and/or developmental and intellectual disabilities. Therefore, the embryos with chromosomal deletion revealed by DNA microarray should not be transferred to the patients, or further gene map and/or phenotype seeking is necessary before making a final decision. PMID:24409323

He, Wenyin; Sun, Xiaofang; Liu, Lian; Li, Man; Jin, Hua; Wang, Wei-Hua

2014-01-01

54

Rescuing Human Embryonic Stem Cell Research: The Blastocyst Transfer Method  

Microsoft Academic Search

Despite the therapeutic potential of human embryonic stem (HES) cells, many people believe that HES cell research should be banned. The reason is that the present method of extracting HES cells involves the destruction of the embryo, which for many is the beginning of a person. This paper examines a number of compromise solutions such as parthenogenesis, the use of

S. Matthew Liao

2005-01-01

55

The rate of blastocysts production following vitrification with step-wise equilibration of immature mouse oocytes  

PubMed Central

Background: Cryopreservation and in vitro maturation (IVM) of oocyte is becoming an important technique in infertility treatment and fertility preservation. Also it has been proposed to establish a genetic resource bank for endangered or commercially important animal species. Objective: The aim of this study was to evaluate viability, maturation and fertilization rate of mouse immature oocytes after single and stepwise vitrification procedure. Materials and Methods: Oocytes were obtained from 4 weeks old female mice 48h after intraperitoneal injection of 7.5 IU pregnant mare serum gonadotropin (PMSG). Collected oocytes before vitrification were exposed to cryoprotectant, which was composed of 30% (v/v) ethylene glycol, 18% (w/v) Ficoll-70, and 0.3 M sucrose, either by single step or in a step-wise way. After vitrification and storage in liquid nitrogen, the oocytes were warmed and washed two times in medium TCM199 and then subjected to IVM, fertilization and subsequent development to blastocysts. Results: The oocytes survival rates after vitrifying-warming (88.96%), maturation rate (73.23%), the capacity of fertilization (57.80%) and embryonic development to blastocyst (16.41%) in the step-wise exposure were significantly higher (p<0.001) compared with corresponding rate in the single step procedure. Conclusion: The results suggest that vitrification with step-wise procedure has positive effects on maturation and developmental capacity of mice germinal vesicle oocytes in compare with single step vitrification procedure. PMID:25246911

Mahmoudi, Reza; Rajaei, Farzad; Ragardi Kashani, Iraj; Abbasi, Mehdi; Amidi, Fardin; Sobhani, Aligholi; Amiri, Iraj

2012-01-01

56

44 the effect of sucrose concentration for single-step dilution on the viability of cryotop-vitrified in vitro-produced bovine embryos.  

PubMed

The aim of this study was to test sucrose concentrations for single-step dilution on the viability of vitrified in vitro-produced bovine embryos. Blastocysts (n=173, 7 to 8 days after fertilization) were vitrified using the Cryotop (Kitazato, Tokyo, Japan) method placement by incubating the blastocysts in Dulbecco's phosphate buffered saline supplemented with 20% calf serum, 7.5% ethylene glycol, and 7.5% dimethyl sulfoxide for 3min and then transferring into vitrification solution (Dulbecco's phosphate buffered saline supplemented with 20% calf serum, 16.5% ethylene glycol, 16.5% dimethyl sulfoxide, and 0.5M sucrose). Each embryo was placed on a Cryotop with minimum volume of vitrification solution, and then the Cryotop was plunged into liquid nitrogen. Total time from placement in vitrification solution to plunging into liquid nitrogen was 1min. The blastocysts were warmed by incubation in the single-step dilution medium for 5min [0M sucrose (n=42), 0.25M sucrose (n=44), 0.5M sucrose (n=43), and 1.0M sucrose (n=44)] at 38.0°C. After dilution, the embryos were washed in TCM-199 supplemented with 20% calf serum and 0.1mM ?-mercaptoethanol and were cultured for 72h in the same medium at 38.5°C in an atmosphere of 5% CO2. The rates of re-expanded blastocysts and hatched blastocysts were determined at 24 and 72h after warming, respectively. Data were analysed using the chi-squared test. The percent of re-expanded blastocysts at 24h after warming in dilution medium supplemented with any level of sucrose was significantly higher (P<0.05) than in blastocysts warmed without sucrose (Table 1). The hatched blastocyst rate of embryos at 72h after warming in dilution medium with 0.5M sucrose was significant higher than that with no sucrose. There were no differences in hatched blastocyst rates between the sucrose concentrations supplemented to the dilution medium. These results suggest that embryos vitrified by the Cryotop method can be diluted in single-step dilution using 0.25, 0.5, or 1.0M sucrose supplemented to the medium. PMID:25472093

Kondo, S; Imai, K; Dochi, O

2014-12-01

57

Identification and expression analysis of genes associated with bovine blastocyst formation  

Microsoft Academic Search

BACKGROUND: Normal preimplantation embryo development encompasses a series of events including first cleavage division, activation of the embryonic genome, compaction and blastocyst formation. First lineage differentiation starts at the blastocyst stage with the formation of the trophectoderm and the inner cell mass. The main objective of this study was the detection, identification and expression analysis of genes associated with blastocyst

Karen Goossens; Ann Van Soom; Mario Van Poucke; Leen Vandaele; Jo Vandesompele; Alex Van Zeveren; Luc J Peelman

2007-01-01

58

Two cycles with single embryo transfer versus one cycle with double embryo transfer: a randomized controlled trial  

Microsoft Academic Search

BACKGROUND: With the aim of reducing the number of multiple pregnancies after IVF we investigated the effectiveness of two cycles with single embryo transfer (SET) and one cycle with double embryo transfer (DET) after IVF and calculated the cost-effectiveness of both strategies. Methods: A randomized controlled trial was performed in 107 women, aged <35 years, in their first IVF cycle,

H. G. M. Lukassen; D. D. M. Braat; A. M. M. Wetzels; G. A. Zielhuis; E. M. M. Adang; E. Scheenjes; J. A. M. Kremer

2005-01-01

59

Two cycles with single embryo transfer versus one cycle with double embryo transfer: a randomized controlled trial  

Microsoft Academic Search

BACKGROUND: With the aim of reducing the number of multiple pregnancies after IVF we investigated the effectiveness of two cycles with single embryo transfer (SET) and one cycle with double embryo transfer (DET) after IVF and calculated the cost-effectiveness of both strategies. Methods: A randomized controlled trial was per- formed in 107 women, aged <35 years, in their first IVF

H. G. M. Lukassen; D. D. Braat; Alex M. M. Wetzels; Gerhard A. Zielhuis; Eddy M. M. Adang; Eduard Scheenjes; Jan A. M. Kremer

2004-01-01

60

Day 3 versus day 5 embryo transfer: a prospective randomized study  

Microsoft Academic Search

Transfer of embryos at the blastocyst stage has been associated with exceptionally high implantation rates. There are, however, only a few prospective randomized studies comparing day 3 versus day 5 embryo transfer. Furthermore, the number of embryos replaced in the day 3 group transfer is often higher than the number of blastocysts replaced, thereby affecting implantation rates. A total of

M Bungum; L Bungum; P Humaidan; C Yding Andersen

2003-01-01

61

Controlling energy transfer between multiple dopants within a single nanoparticle  

PubMed Central

Complex core-shell architectures are implemented within LaF3 nanoparticles to allow for a tailored degree of energy transfer (ET) between different rare earth dopants. By constraining specific dopants to individual shells, their relative distance to one another can be carefully controlled. Core-shell LaF3 nanoparticles doped with Tb3+ and Eu3+ and consisting of up to four layers were synthesized with an outer diameter of ?10 nm. It is found that by varying the thicknesses of an undoped layer between a Tb3+-doped layer and a Eu3+-doped layer, the degree of ET can be engineered to allow for zero, partial, or total ET from a donor ion to an acceptor ion. More specifically, the ratio of the intensities of the 541-nm Tb3+ and 590 nm Eu3+ peaks was tailored from <0.2 to ?2.4 without changing the overall composition of the particles but only by changing the internal structure. Further, the emission spectrum of a blend of singly doped nanoparticles is shown to be equivalent to the spectra of co-doped particles when a core-shell configuration that restricts ET is used. Beyond simply controlling ET, which can be limiting when designing materials for optical applications, this approach can be used to obtain truly engineered spectral features from nanoparticles and composites made from them. Further, it allows for a single excitation source to yield multiple discrete emissions from numerous lanthanide dopants that heretofore would have been quenched in a more conventional active optical material. PMID:18250307

DiMaio, Jeffrey R.; Sabatier, Clément; Kokuoz, Baris; Ballato, John

2008-01-01

62

Isolation and characterization of a bovine visceral endoderm cell line derived from a parthenogenetic blastocyst.  

PubMed

A cell line, BPE-1, was derived from a parthenogenetic 8-d in vitro-produced bovine blastocyst that produced a cell outgrowth on STO feeder cells. The BPE-1 cells resembled visceral endoderm previously cultured from blastocysts produced by in vitro fertilization (IVF). Analysis of the BPE-1 cells demonstrated that they produced serum proteins and were negative for interferon-tau production (a marker of trophectoderm). Transmission electron microscopy revealed that the cells were a polarized epithelium connected by complex junctions resembling tight junctions in conjunction with desmosomes. Rough endoplasmic reticulum was prominent within the cells as were lipid vacuoles. Immunocytochemistry indicated the BPE-1 cells had robust microtubule networks. These cells have been grown for over 2 yr for multiple passages at 1:10 or 1:20 split ratios on STO feeder cells. The BPE-1 cell line presumably arose from embryonic cells that became diploid soon after parthenogenetic activation and development of the early embryo. However, metaphase spreads prepared at passage 41 indicated that the cell population had a hypodiploid (2n = 60) unimodal chromosome content with a mode of 53 and a median and mean of 52. The cell line will be of interest for functional comparisons with bovine endoderm cell lines derived from IVF and nuclear transfer embryos. PMID:16153145

Talbot, Neil C; Caperna, Thomas J; Powell, Anne M; Ealy, Alan D; Blomberg, Le Ann; Garrett, Wesley M

2005-01-01

63

Single-phase heat transfer in microchannels: The importance of scaling effects  

Microsoft Academic Search

Microscale single-phase heat transfer is widely used in industrial and scientific applications and for this reason, many related papers have been published in the last two decades. Nevertheless, inconsistencies between published results still exist and there is no generally accepted model for the prediction of single-phase heat transfer in microchannels. This paper presents a review of the experimental and numerical

P. Rosa; T. G. Karayiannis; M. W. Collins

2009-01-01

64

Single-element Electron-transfer Optical Detector System  

NASA Technical Reports Server (NTRS)

An optical detector system includes an electrically resistive screen that is substantially transparent to radiation energy having a wavelength of interest. An electron transfer element (e.g., a low work function photoactive material or a carbon nanotube (CNT)-based element) has a first end and a second end with its first end spaced apart from the screen by an evacuated gap. When radiation energy passes through the screen with a bias voltage being applied thereto, transfer of electrons through the electron transfer element is induced from its first to its second end such that a quantity indicative of the electrons transferred can be detected.

Jordan, Jeffrey D. (Inventor)

2004-01-01

65

The accuracy of chromosomal microarray testing for identification of embryonic mosaicism in human blastocysts  

PubMed Central

Background Most previous studies of chromosomal mosaicism in IVF embryos were performed by fluorescence in situ hybridization (FISH) methods. While there are reports implicating chromosome aneuploidy in implantation failure following transfer and pregnancy loss by spontaneous miscarriage, the significance of mosaicism for the developmental potential of growing embryos is unknown. However, the low prevalence of chromosomal mosaicism in chorionic villus sampling and amniotic fluid specimens suggests the presence of selection against mosaic embryos for implantation and early pregnancy. The absence of evidence for selective allocation of abnormal cells to the trophectoderm (TE) of mosaic blastocysts permits these cells to be a good proxy for embryonic mosaicism detection by chromosomal microarrays (CMA). The purpose of this study was to establish the limits of detection and the prevalence of chromosome mosaicism in day 5/6 human embryos using CMA with TE biopsies. Results From reconstitution experiments we established log2 ratio thresholds for mosaicism detection. These studies indicated that chromosomal mosaicism at levels as low as between 25-37% can be consistently identified. Follow-up studies by FISH on non-transferred abnormal embryos confirmed the diagnostic accuracy of CMA testing. The number of cells in a TE biopsy can influence mosaicism detection. Conclusions Chromosomal microarrays can detect mosaicism in TE biopsies when present at levels as low as between 25-37% and the prevalence of day 5/6 blastocysts which were mosaic and had no other abnormalities reached 15% among a cohort of 551 embryos examined. Validated protocols for establishing detection thresholds for mosaicism are important to reduce the likelihood of transferring abnormal embryos. PMID:24581286

2014-01-01

66

Aseptic minimum volume vitrification technique for porcine parthenogenetically activated blastocyst.  

PubMed

Minimum volume vitrification may provide extremely high cooling and warming rates if the sample and the surrounding medium contacts directly with the respective liquid nitrogen and warming medium. However, this direct contact may result in microbial contamination. In this work, an earlier aseptic technique was applied for minimum volume vitrification. After equilibration, samples were loaded on a plastic film, immersed rapidly into factory derived, filter-sterilized liquid nitrogen, and sealed into sterile, pre-cooled straws. At warming, the straw was cut, the filmstrip was immersed into a 39 degree C warming medium, and the sample was stepwise rehydrated. Cryosurvival rates of porcine blastocysts produced by parthenogenetical activation did not differ from control, vitrified blastocysts with Cryotop. This approach can be used for minimum volume vitrification methods and may be suitable to overcome the biological dangers and legal restrictions that hamper the application of open vitrification techniques. PMID:21468455

Lin, Lin; Yu, Yutao; Zhang, Xiuqing; Yang, Huanming; Bolund, Lars; Callesen, Henrik; Vajta, Gábor

2011-01-01

67

Single crystal to single crystal transformation and hydrogen-atom transfer upon oxidation of a cerium coordination compound.  

PubMed

Trivalent and tetravalent cerium compounds of the octamethyltetraazaannulene (H2omtaa) ligand have been synthesized. Electrochemical analysis shows a strong thermodynamic preference for the formal cerium(IV) oxidation state. Oxidation of the cerium(III) congener Ce(Homtaa)(omtaa) occurs by hydrogen-atom transfer that includes a single crystal to single crystal transformation upon exposure to an ambient atmosphere. PMID:23534677

Williams, Ursula J; Mahoney, Brian D; Lewis, Andrew J; DeGregorio, Patrick T; Carroll, Patrick J; Schelter, Eric J

2013-04-15

68

Relationship between reactive oxygen species and autophagy in dormant mouse blastocysts during delayed implantation  

PubMed Central

Objective Under estrogen deficiency, blastocysts cannot initiate implantation and enter dormancy. Dormant blastocysts live longer in utero than normal blastocysts, and autophagy has been suggested as a mechanism underlying the sustained survival of dormant blastocysts during delayed implantation. Autophagy is a cellular degradation pathway and a central component of the integrated stress response. Reactive oxygen species (ROS) are produced within cells during normal metabolism, but their levels increase dramatically under stressful conditions. We investigated whether heightened autophagy in dormant blastocysts is associated with the increased oxidative stress under the unfavorable condition of delayed implantation. Methods To visualize ROS production, day 8 (short-term dormancy) and day 20 (long-term dormancy) dormant blastocysts were loaded with 1-µM 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA). To block autophagic activation, 3-methyladenine (3-MA) and wortmannin were used in vivo and in vitro, respectively. Results We observed that ROS production was not significantly affected by the status of dormancy; in other words, both dormant and activated blastocysts showed high levels of ROS. However, ROS production was higher in the dormant blastocysts of the long-term dormancy group than in those of the short-term group. The addition of wortmannin to dormant blastocysts in vitro and 3-MA injection in vivo significantly increased ROS production in the short-term dormant blastocysts. In the long-term dormant blastocysts, ROS levels were not significantly affected by the treatment of the autophagy inhibitor. Conclusion During delayed implantation, heightened autophagy in dormant blastocysts may be operative as a potential mechanism to reduce oxidative stress. Further, ROS may be one of the potential causes of compromised developmental competence of long-term dormant blastocysts after implantation. PMID:25309857

Shin, Hyejin; Choi, Soyoung

2014-01-01

69

Limitations of a time-lapse blastocyst prediction model: a large multicentre outcome analysis.  

PubMed

The goal of embryo selection models is to select embryos with the highest reproductive potential, whilst minimizing the rejection of viable embryos. Ultimately, any embryo selection model must be tested on clinical outcome. We therefore retrospectively tested a published blastocyst prediction model on a large combined set of transferred embryos with known clinical outcome. The model was somewhat effective in that we found a relative increase of 30% for implantation in the model-selected group of embryos. There was, however, a concomitant large rejection of embryos from our test cohort, which actually resulted in pregnancy. This hypothetical experiment highlights the limitations of predicting blastulation only. Crucially, it illustrates that both sensitivity and specificity are important parameters when developing embryo selection models for prospective clinical use. PMID:24912418

Kirkegaard, Kirstine; Campbell, Alison; Agerholm, Inge; Bentin-Ley, Ursula; Gabrielsen, Anette; Kirk, John; Sayed, Shabana; Ingerslev, Hans Jakob

2014-08-01

70

Single and pair neutron transfers at sub-barrier energies  

SciTech Connect

Multinucleon transfer cross sections in the {sup 96}Zr+{sup 40}Ca system have been measured, in inverse kinematics, at bombarding energies ranging from the Coulomb barrier to {approx}25% below. Targetlike recoils have been identified in A, Z and velocity with the large solid angle magnetic spectrometer PRISMA. The experimental data for one- and two-neutron transfer channels have been compared with semiclassical microscopic calculations. For the two-neutron transfer channels the relevance of the transitions to the ground state and to the 0{sup +} excited states of {sup 42}Ca are discussed by employing, for the reaction mechanism, the successive approximation. It is found that the transition to the 0{sup +} state at {approx}6 MeV, whose wave function is dominated by the two neutrons in the 2p{sub 3/2} shell, is much larger than the ground state one. The comparison with the inclusive data reveals that transitions to states with high multipolarity and non-natural parity are important. This suggests that more complex two-particle correlations have to be incorporated in the treatment of the transfer process.

Corradi, L.; Fioretto, E.; Michelagnoli, C.; Stefanini, A. M.; Valiente-Dobon, J. J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Szilner, S. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Ruder Boskovic Institute, HR-10 001 Zagreb (Croatia); Pollarolo, G. [Dipartimento di Fisica Teorica, Universita di Torino, and Istituto Nazionale di Fisica Nucleare, I-10125 Torino (Italy); Colo, G. [Dipartimento di Fisica, Universita degli Studi di Milano and Istituto Nazionale di Fisica Nucleare, I-20133 Milano (Italy); Mason, P.; Farnea, E.; Montagnoli, G.; Montanari, D.; Scarlassara, F.; Ur, C. A. [Dipartimento di Fisica, Universita di Padova, and Istituto Nazionale di Fisica Nucleare, I-35131 Padova (Italy); Gadea, A. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Haas, F. [Institut Pluridisciplinaire Hubert Curien, CNRS-IN2P3, Universite de Strasbourg, F-67037 Strasbourg (France); Jelavic-Malenica, D.; Soic, N. [Ruder Boskovic Institute, HR-10 001 Zagreb (Croatia); Marginean, N. [Horia Hulubei National Institute of Physics and Nuclear Engineering, R-077125, Bucharest-Magurele (Romania)

2011-09-15

71

Single-phase convective heat transfer in rod bundles  

Microsoft Academic Search

The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod

Mary V. Holloway; Donald E. Beasley; Michael E. Conner

2008-01-01

72

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel  

E-print Network

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel July 2008 Keywords: Boiling Microchannels Visualisation Flow boiling instabilities Heat transfer a b s t r a c t Boiling in microchannels is widely considered as one of the front runners in process

Aussillous, Pascale

73

The transfer matrix: A tool for comparing single stellar population models  

NASA Astrophysics Data System (ADS)

We present the transfer matrix, an analytical tool designed for the study of the model-induced systematic errors in star formation history reconstructions. It is a generalization of the resolution matrix well known in linear inverse problems theory. An application of the transfer matrix is given using the González-Delgado et al. (2005) single stellar population models.

Ocvirk, P.

2005-12-01

74

Energy Transfer from Nucleic Acids to Tb(III): Selective Emission Enhancement by Single DNA Mismatches  

E-print Network

Energy Transfer from Nucleic Acids to Tb(III): Selective Emission Enhancement by Single DNA energy transfer (EnT) from nucleic acids to Tb3+ has been utilized to investigate the binding of the ions in nucleic acid hybridization assays with applications that range from the determination of genetic

Turro, Claudia

75

Single-node orbit analsyis with radiation heat transfer only  

NASA Technical Reports Server (NTRS)

The steady-state temperature of a single node which dissipates energy by radiation only is discussed for a nontime varying thermal environment. Relationships are developed to illustrate how shields can be utilized to represent a louver system. A computer program is presented which can assess periodic temperature characteristics of a single node in a time varying thermal environment having energy dissipation by radiation only. The computer program performs thermal orbital analysis for five combinations of plate, shields, and louvers.

Peoples, J. A.

1977-01-01

76

GATA6 levels modulate primitive endoderm cell fate choice and timing in the mouse blastocyst.  

PubMed

Cells of the inner cell mass (ICM) of the mouse blastocyst differentiate into the pluripotent epiblast or the primitive endoderm (PrE), marked by the transcription factors NANOG and GATA6, respectively. To investigate the mechanistic regulation of this process, we applied an unbiased, quantitative, single-cell-resolution image analysis pipeline to analyze embryos lacking or exhibiting reduced levels of GATA6. We find that Gata6 mutants exhibit a complete absence of PrE and demonstrate that GATA6 levels regulate the timing and speed of lineage commitment within the ICM. Furthermore, we show that GATA6 is necessary for PrE specification by FGF signaling and propose a model where interactions between NANOG, GATA6, and the FGF/ERK pathway determine ICM cell fate. This study provides a framework for quantitative analyses of mammalian embryos and establishes GATA6 as a nodal point in the gene regulatory network driving ICM lineage specification. PMID:24835466

Schrode, Nadine; Saiz, Néstor; Di Talia, Stefano; Hadjantonakis, Anna-Katerina

2014-05-27

77

Gene expression profiles of vitrified in vitro- and in vivo-derived bovine blastocysts.  

PubMed

Vitrification is becoming a preferred method for pre-implantation embryo cryopreservation. The objective of this study was to determine the differentially expressed genes of in vivo- and in vitro-produced bovine embryos after vitrification. In vitro- (IVF) and in vivo-derived (IVV) bovine blastocysts were identified as follows: in vitro-produced fresh (IVF-F), in vitro-produced vitrified (IVF-V), in vivo-derived fresh (IVV-F), in vivo-derived vitrified (IVV-V). The microarray results showed that 53 genes were differentially regulated between IVF and IVV, and 121 genes were differentially regulated between fresh and vitrified blastocysts (P?blastocysts (P?blastocysts. Significantly up-regulated KEGG pathways included ribosome, oxidative phosphorylation, spliceosome, and oocyte meiosis in the fresh IVF blastocyst samples, while sphingolipid and purine metabolisms were up-regulated in the vitrified IVF blastocyst. The results showed that in vitro bovine blastocyst production protocols used in this study caused no major gene expression differences compared to those of in vivo-produced blastocysts. After vitrification, however, in vitro-produced blastocysts showed major gene expression differences compared to in vivo blastocysts. This study suggests that in vitro-produced embryos are of comparable quality to their in vivo counterparts. Vitrification of in vitro blastocysts, on the other hand, causes significant up-regulation of genes that are involved in stress responses. PMID:22778065

Aksu, Digdem Aktoprakligil; Agca, Cansu; Aksu, Soner; Bagis, Haydar; Akkoc, Tolga; Caputcu, Arzu Tas; Arat, Sezen; Taskin, Ali Cihan; Kizil, Sedat H; Karasahin, Tahir; Akyol, Numan; Satilmis, Muharrem; Sagirkaya, Hakan; Ustuner, Burcu; Nur, Zekeriya; Agca, Yuksel

2012-09-01

78

The Influence of Polyvinylpyrrolidone on Freezing of Bovine IVF Blastocysts Following Biopsy  

Microsoft Academic Search

A study was conducted to develop a better freezing protocol for in vitro developed biopsied bovine blastocysts. Biopsied blastocysts were exposed to 1.8 M ethylene glycol (EG) + 0.05 M trehalose (T) and different concentration (5, 10, and 20%) of polyvinylpyrrolidone (PVP). Exposure to the solutions alone did not affect their in vitro development (Experiment 1). Experiments 2, 3, and

T. Suzuki; S. Saha; C. Sumantri; M. Takagi; A. Boediono

1995-01-01

79

Uterine Micro-Environment and Estrogen-Dependent Regulation of Osteopontin Expression in Mouse Blastocyst  

PubMed Central

Embryo implantation is a highly synchronized bioprocess between an activated blastocyst and a receptive uterus. In mice, successful implantation relies on the dynamic interplay of estrogen and progesterone; however, the key mediators downstream of these hormones that act on blastocyst competency and endometrium receptivity acquisition are largely unknown. In this study, we showed that the expression of osteopontin (OPN) in mouse blastocysts is regulated by ovarian estrogen and uterine micro-environment. OPN mRNA is up-regulated in mouse blastocyst on day 4 of pregnancy, which is associated with ovarian estrogen secretion peak. Hormone treatment in vivo demonstrated that OPN expression in a blastocyst is regulated by estrogen through an estrogen receptor (ER). Our results of the delayed and activated implantation model showed that OPN expression is induced after estrogen injection. While estrogen treatment during embryo culture in vitro showed less effect on OPN expression, the tubal ligation model on day 3 of pregnancy confirmed that the regulation of estrogen on OPN expression in blastocyst might, through some specific cytokines, have existed in a uterine micro-environment. Collectively, our study presents that estrogen regulates OPN expression and it may play an important role during embryo implantation by activating blastocyst competence and facilitating the endometrium acceptable for active blastocyst. PMID:23852023

Xie, Qing-Zhen; Qi, Qian-Rong; Chen, Ying-Xian; Xu, Wang-Ming; Liu, Qian; Yang, Jing

2013-01-01

80

Uterine micro-environment and estrogen-dependent regulation of osteopontin expression in mouse blastocyst.  

PubMed

Embryo implantation is a highly synchronized bioprocess between an activated blastocyst and a receptive uterus. In mice, successful implantation relies on the dynamic interplay of estrogen and progesterone; however, the key mediators downstream of these hormones that act on blastocyst competency and endometrium receptivity acquisition are largely unknown. In this study, we showed that the expression of osteopontin (OPN) in mouse blastocysts is regulated by ovarian estrogen and uterine micro-environment. OPN mRNA is up-regulated in mouse blastocyst on day 4 of pregnancy, which is associated with ovarian estrogen secretion peak. Hormone treatment in vivo demonstrated that OPN expression in a blastocyst is regulated by estrogen through an estrogen receptor (ER). Our results of the delayed and activated implantation model showed that OPN expression is induced after estrogen injection. While estrogen treatment during embryo culture in vitro showed less effect on OPN expression, the tubal ligation model on day 3 of pregnancy confirmed that the regulation of estrogen on OPN expression in blastocyst might, through some specific cytokines, have existed in a uterine micro-environment. Collectively, our study presents that estrogen regulates OPN expression and it may play an important role during embryo implantation by activating blastocyst competence and facilitating the endometrium acceptable for active blastocyst. PMID:23852023

Xie, Qing-Zhen; Qi, Qian-Rong; Chen, Ying-Xian; Xu, Wang-Ming; Liu, Qian; Yang, Jing

2013-01-01

81

Gigahertz single-hole transfer in Si tunable-barrier pumps  

NASA Astrophysics Data System (ADS)

We report high-speed single-hole (SH) transfer using Si tunable-barrier pumps comprising p-type metal-oxide-semiconductor field-effect transistors. A clear SH-transfer-current plateau with the current level of about 160 pA was observed when a clock signal having a frequency of 1 GHz was applied to one of the gates. Temperature dependence measurements of the transfer current reveal that the transfer probability is dominated by non-equilibrium SH escape by thermal hopping from the electrically formed charge island. The lower bound of the relative error rate for the 1-GHz transfer is about 10-3 at a temperature of about 17 K. In addition, we investigate the frequency dependence of the transfer, where we discuss possible sources causing the change in the error rate. These results pave the way for accurate manipulation of SHs and its application to metrological current standards.

Yamahata, Gento; Karasawa, Takeshi; Fujiwara, Akira

2015-01-01

82

Chemical reaction fouling model for single-phase heat transfer  

SciTech Connect

A fouling model was developed on the premise that the chemical reaction for generation of precursor can take place in the bulk fluid, in the thermalboundary layer, or at the fluid/wall interface, depending upon the interactive effects of flu id dynamics, heat and mass transfer, and the controlling chemical reaction. The analysis was used to examine the experimental data for fouling deposition of polyperoxides produced by autoxidation of indene in kerosene. The effects of fluid and wall temperatures for two flow geometries were analyzed. The results showed that the relative effects of physical parameters on the fouling rate would differ for the three fouling mechanisms; therefore, it is important to identify the controlling mechanism in applying the closed-flow-loop data to industrial conditions.

Panchal, C.B. [Argonne National Lab., IL (United States); Watkinson, A.P. [British Columbia Univ., Vancouver, BC (Canada)

1993-08-01

83

Accumulation of RNA in blastocysts during embryonic diapause and the periimplantation period in the western spotted skunk  

Microsoft Academic Search

The in vivo incorporation of TH-uridine into RNA was studied in delayed implanting and activated blastocysts obtained from 33 western spotted skunks. TH-uridine was incorporated into RNA by all blastocysts; however, significantly more label was incorporated as blastocyst diameter increased. Activated blastocysts with diameters of 1.6 mm or greater on average incorporated 65 times more TH-precursor in 5 hr than

Rodney A. Mead; A. W. Rourke

1985-01-01

84

Poisson-distributed electron-transfer dynamics from single quantum dots to C60 molecules.  

PubMed

Functional quantum dot (QD)-based nanostructures are often constructed through the self-assembly of QDs with binding partners (molecules or other nanoparticles), a process that leads to a statistical distribution of the number of binding partners. Using single QD fluorescence spectroscopy, we probe this distribution and its effect on the function (electron-transfer dynamics) in QD-C60 complexes. Ensemble-averaged transient absorption and fluorescence decay as well as single QD fluorescence decay measurements show that the QD exciton emission was quenched by electron transfer from the QD to C60 molecules and the electron-transfer rate increases with the C60-to-QD ratio. The electron-transfer rate of single QD-C60 complexes fluctuates with time and varies among different QDs. The standard deviation increases linearly with the average of electron-transfer rates of single QD-C60 complexes, and the distributions of both quantities obey Poisson statistics. The observed distributions of single QD-C60 complexes and ensemble-averaged fluorescence decay kinetics can be described by a model that assumes a Poisson distribution of the number of adsorbed C60 molecules per QD. Our findings suggest that, in self-assembled QD nanostructures, the statistical distribution of the number of adsorbed partners can dominate the distributions of the averages and standard deviation of their interfacial dynamical properties. PMID:21190376

Song, Nianhui; Zhu, Haiming; Jin, Shengye; Zhan, Wei; Lian, Tianquan

2011-01-25

85

Anomalous small charge transfer in doped single wall carbon nanohorn aggregates with Li, K and Br  

NASA Astrophysics Data System (ADS)

Single wall carbon nanohorns (SWNHs) produced by CW CO2 laser vaporization of a carbon target are examined for their ability to undergo charge transfer reactions. A typical SWNH has been shown by HRTEM to be a short ( ~ 40 nm) ~ 2 nm diameter nanotube with a conical tip ( ~ 20 ^circ full cone angle). Charge transfer chemical doping of SWNHs with K and Br was examined by vapor phase reaction and studied by Raman scattering. Electrochemical Li ion doping was also carried out. All these experiments indicate that an anomalously small charge transfer occurs for SWNHs in sharp contrast to the behavior observed for single wall carbon nanotube bundles and graphite. This rather remarkable result is not understood at present. The Raman spectrum (488 nm excitation) exhibits a pair of surprisingly narrow bands at 1350 and 1580 cm -1 with nearly equal intensity. These bands shift due to charge transfer.

Bandow, S.; Iijima, S.; Rao, A. M.; Sumanasekera, G. U.; Eklund, P. C.; Kokai, F.; Takahashi, K.; Yudasaka, M.

2000-03-01

86

Nanophotonic enhancement of the F\\"orster resonance energy transfer rate on single DNA molecules  

E-print Network

Nanophotonics achieves accurate control over the luminescence properties of a single quantum emitter by tailoring the light-matter interaction at the nanoscale and modifying the local density of optical states (LDOS). This paradigm could also benefit to F\\"orster resonance energy transfer (FRET) by enhancing the near-field electromagnetic interaction between two fluorescent emitters. Despite the wide applications of FRET in nanosciences, using nanophotonics to enhance FRET remains a debated and complex challenge. Here, we demonstrate enhanced energy transfer within single donor-acceptor fluorophore pairs confined in gold nanoapertures. Experiments monitoring both the donor and the acceptor emission photodynamics at the single molecule level clearly establish a linear dependence of the FRET rate on the LDOS in nanoapertures. These findings are applied to enhance the FRET rate in nanoapertures up to six times, demonstrating that nanophotonics can be used to intensify the near-field energy transfer and improve t...

Ghenuche, Petru; Moparthi, Satish Babu; Grigoriev, Victor; Wenger, Jérôme

2014-01-01

87

Solving the atmospheric scattering optical transfer function using the multi-coupled single scattering method  

NASA Astrophysics Data System (ADS)

The atmospheric scattering optical transfer function (OTF) is solved by applying the multi-coupled single scattering (MCSS) method to the three-dimensional radiative transfer equation (RTE) under the periodic ground condition. This approach is a direct hit to the atmospheric scattering OTF using the same original context of modulation transfer function (MTF) measurement, i.e., images of sinusoidal grating at different spatial frequencies. Both the amplitude and phase shift of the OTF at various zenith and azimuth angles can be obtained at an arbitrary spatial frequency.

Sun, Bin; Hong, Jin; Sun, Xiao-Bing

2014-09-01

88

Time-resolved energy transfer from single chloride-terminated nanocrystals to graphene  

SciTech Connect

We examine the time-resolved resonance energy transfer of excitons from single n-butyl amine-bound, chloride-terminated nanocrystals to two-dimensional graphene through time-correlated single photon counting. The radiative biexponential lifetime kinetics and blinking statistics of the individual surface-modified nanocrystal elucidate the non-radiative decay channels. Blinking modification as well as a 4× reduction in spontaneous emission were observed with the short chloride and n-butylamine ligands, probing the energy transfer pathways for the development of graphene-nanocrystal nanophotonic devices.

Ajayi, O. A., E-mail: oaa2114@columbia.edu, E-mail: cww2104@columbia.edu; Wong, C. W., E-mail: oaa2114@columbia.edu, E-mail: cww2104@columbia.edu [Optical Nanostructures Laboratory, Center for Integrated Science and Engineering, Solid-State Science and Engineering, Columbia University, New York, New York 10027 (United States); Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States); Anderson, N. C.; Wolcott, A.; Owen, J. S. [Department of Chemistry, Columbia University, New York, New York 10027 (United States); Cotlet, M. [Brookhaven National Laboratory, Upton, New York, New York 11973 (United States); Petrone, N.; Hone, J. [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States); Gu, T.; Gesuele, F. [Optical Nanostructures Laboratory, Center for Integrated Science and Engineering, Solid-State Science and Engineering, Columbia University, New York, New York 10027 (United States)

2014-04-28

89

Time-resolved energy transfer from single chloride-terminated nanocrystals to graphene  

NASA Astrophysics Data System (ADS)

We examine the time-resolved resonance energy transfer of excitons from single n-butyl amine-bound, chloride-terminated nanocrystals to two-dimensional graphene through time-correlated single photon counting. The radiative biexponential lifetime kinetics and blinking statistics of the individual surface-modified nanocrystal elucidate the non-radiative decay channels. Blinking modification as well as a 4× reduction in spontaneous emission were observed with the short chloride and n-butylamine ligands, probing the energy transfer pathways for the development of graphene-nanocrystal nanophotonic devices.

Ajayi, O. A.; Anderson, N. C.; Cotlet, M.; Petrone, N.; Gu, T.; Wolcott, A.; Gesuele, F.; Hone, J.; Owen, J. S.; Wong, C. W.

2014-04-01

90

Expression of HSG is essential for mouse blastocyst formation  

SciTech Connect

It has been shown recently that hyperplasia suppressor gene (HSG) is a powerful regulator for cell proliferation and has a critical role in mitochondrial fusion in many cells. However, little is known about its expression, localization, and function during oocyte maturation and early embryogenesis. In this study, with indirect immunofluorescent staining and Western blotting, we found that HSG was expressed in mouse oocytes and preimplantation embryos which primarily exhibited a submembrane distribution pattern in the cytoplasm. Moreover, HSG mainly associated with {beta}-tubulin during oocyte maturation and early embryonic development. When mouse zygotes were injected with HSG antisense plasmid and cultured in vitro, their capacity to form blastocysts was severely impaired. Our results indicate that HSG plays an essential role in mouse preimplantation development.

Jiang Guangjian [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China); Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017 (China); Department of Biochemistry and Molecular Biology, North China Coal Medical College, Tangshan 063000 (China); Pan Lei [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100080 (China); Huang Xiuying [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China); Han Mei [Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017 (China); Wen Jinkun [Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017 (China)]. E-mail: wjk@hebmu.edu.cn; Sun Fangzhen [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: fzsun@genetics.ac.cn

2005-09-23

91

Accumulation of RNA in blastocysts during embryonic diapause and the periimplantation period in the western spotted skunk  

SciTech Connect

The in vivo incorporation of TH-uridine into RNA was studied in delayed implanting and activated blastocysts obtained from 33 western spotted skunks. TH-uridine was incorporated into RNA by all blastocysts; however, significantly more label was incorporated as blastocyst diameter increased. Activated blastocysts with diameters of 1.6 mm or greater on average incorporated 65 times more TH-precursor in 5 hr than diapausing blastocysts with diameters of 1.1 mm or less. Polyadenylated RNA was likewise synthesized by delayed implanting and activated skunk blastocysts; however, the proportion of polyadenylated RNA synthesized by the former was greater than in the latter. The data suggest that the transition from embryonic diapause to fully activated blastocysts first occurs gradually for several days before entering a 1-2-day period of rapid development characterized by an abrupt increase in RNA accumulation.

Mead, R.A.; Rourke, A.W.

1985-07-01

92

Spectroscopy of single phycoerythrocyanin monomers: dark state identification and observation of energy transfer heterogeneities.  

PubMed Central

Phycoerythrocyanin (PEC) is part of the light harvesting system of cyanobacteria. The PEC monomer contains one phycoviolobilin chromophore, which transfers excitation energy onto two phycocyanobilin chromophores. Many spectroscopical methods have been used in the past to study the bulk properties of PEC. These methods average over many molecules. Therefore, differences in the behavior of individual molecules remain hidden. The energy transfer within photosynthetic complexes is however sensitive to changes in the spectroscopic properties of the participating subunits. Knowledge about heterogeneities is therefore important for the description of the energy transfer in photosynthetic systems. Here, the recording of the fluorescence emission of single PEC molecules is used as a tool to obtain such information. Spectrally resolved detection as well as double resonance excitation of single PEC molecules is used to investigate their bleaching behavior. The trans isomer of the phycoviolobilin chromophore is identified as a short-lived dark state of monomeric PEC. Polarization sensitive single molecule detection is used for the direct observation of the energy transfer in individual PEC molecules. The experiments reveal that more than one-half of the PEC molecules exhibit an energy transfer behavior significantly different from the bulk. These heterogeneities persist on a time scale of several seconds. Model calculations lead to the conclusion that they are caused by minor shifts in the spectra of the chromophores. PMID:12080129

Zehetmayer, P; Hellerer, Th; Parbel, A; Scheer, H; Zumbusch, A

2002-01-01

93

Frictional and heat transfer characteristics of single-phase microchannel liquid flows  

Microsoft Academic Search

In this paper, we review the literature on flow frictional and heat transfer characteristics of single-phase liquid flows through microchannels. The work accentuates the existing discord between experimental observations of microscale transport process characteristics and the corresponding theoretical predictions on the basis of the classical paradigms. The role of microscale effects in inducing such disparity between experimental and theoretical frameworks,

Ranabir Dey; Tamal Das; Suman Chakraborty

2011-01-01

94

Frictional and Heat Transfer Characteristics of Single-Phase Microchannel Liquid Flows  

Microsoft Academic Search

In this paper, we review the literature on flow frictional and heat transfer characteristics of single-phase liquid flows through microchannels. The work accentuates the existing discord between experimental observations of microscale transport process characteristics and the corresponding theoretical predictions on the basis of the classical paradigms. The role of microscale effects in inducing such disparity between experimental and theoretical frameworks,

Ranabir Dey; Tamal Das; Suman Chakraborty

2012-01-01

95

Single-molecule protein folding: Diffusion fluorescence resonance energy transfer studies  

E-print Network

Single-molecule protein folding: Diffusion fluorescence resonance energy transfer studies for protein folding studies and has been extensively stud- ied, both experimentally (at the ensemble level concentration. It is shown that new infor- mation about different aspects of the protein folding reaction can

Croquette, Vincent

96

Single Transferable Vote with Borda Elimination: A New Vote Counting System  

Microsoft Academic Search

Dummett (1997) notes particular difficulties with single transferable vote (STV) and proposes an alternative vote counting system called “Quota\\/Borda system” (QBS) to remedy specific difficulties. I propose an alternative system, structurally related to QBS, which accomplishes similar solutions but has some significant differences. This alternative system is identical to STV in all aspects except one. It eliminates candidates in reverse

Chris Geller

2002-01-01

97

Near-resonant vibration. -->. vibration energy transfer under single-collision conditions. [Propynal  

SciTech Connect

Energy transfer in single collisions of propynal (HC triple bond C-CHO) subsequent to ir multiphonon absorption (CO/sub 2/ laser) was studied. SiF/sub 4/, CH/sub 3/F, CCl/sub 4/, and CH/sub 4/ were added. (DLC)

Breener, D M

1981-01-01

98

137 splitting of ivp bovine blastocyst affects morphology and global gene expression of resulting demi-embryos during elongation.  

PubMed

Embryo splitting has been used since the early 1980s to produce identical twins and increase the pregnancy rate per available embryo. However, very little is known about the effect of splitting on embryo development and competence. Indeed splitting could provoke a negative effect on embryo survival and it can be presumed that each demi-embryo might respond differently to the injury. In this sense, even when embryos are genetically and morphologically identical at the moment of splitting, their developmental potential and molecular characteristics might change as a consequence of the intense manipulation or epigenetic differences due to the interaction with the environment. We have proposed an approach to evaluate the effect of blastocyst splitting on the morphological and gene expression in in vivo development up to the filamentous stage. For that, the effect of splitting on bovine embryo development was evaluated during the elongation period by transferring split and nonsplit IVF-derived blastocysts to cattle recipients and collecting them at Day 17 of development. The number of collected embryos, embryo size, and global gene expression was compared between both groups. Collected elongated embryos derived from split blastocyst were compared with time matched collected control embryos. From 14 transferred hemi-embryos, 5 (35.7%) were collected while 9 elongated from 17 controls were recovered (52.9%). Neither the recovery rate nor the average length of the elongated embryos was significantly different between the two treatments. However, when embryos were rated depending on their size, more than 50% of embryos from the control group had a length surpassing 100mm, while only 33% of the split embryos reached that size. Global gene expression was performed using 2-colour microarray-based gene expression analysis. This was a whole-genome microarray study comparing 10 individual elongated embryos derived from split and nonsplit IVF blastocysts. Genes were considered differentially expressed if the fold change is greater than 2 (up or down-regulation) with P?0.05. A total of 29585 transcripts were detected in all embryos. From those, 449 (1.5%) were differentially expressed between elongated embryos derived from split and nonsplit IVF blastocysts, among them, 248 (0.83%) genes were down-regulated and 201 (0.67%) genes were up-regulated in split embryos. Gene ontology analysis identified deregulated genes related with intrinsic component of membrane (ELOVL7, GJA1, LAPTM4B, LDLR, SLC18A2, SLC1A3, SLC38A5, TSPAN13), lipid transporter activity (RBP4, APOA1, MTTP), and organophosphate ester transport (GJA1, GJB1, ATP9B). In conclusion, we showed that splitting affect the in vivo developmental capability and gene expression profile during the elongation period of bovine embryos. However, further studies are needed to determine the long-term effect of this technique to produce viable offspring. PMID:25472186

Velásquez, A E; Veraguas, D; Cox, J F; Castro, F O; Rodriguez, L L

2014-12-01

99

86 birth of healthy calves after intrafollicular oocyte transfer.  

PubMed

The in vitro production (IVP) of bovine embryos is a well-established technique that has been available for nearly 20 years. However, there remain major differences between IVP-derived blastocysts and their in vivo-derived counterparts. Many studies have pointed out that most of these differences are due to the in vitro developmental environment. To circumvent these negative effects due to in vitro culture conditions, a new method - intrafollicular oocyte transfer (IFOT) - was established in the present study. Using modified ovum pick-up (OPU) equipment, in vitro-matured oocytes derived from slaughterhouse ovaries were injected into the dominant preovulatory follicle of synchronised heifers (follicular recipients) enabling subsequent ovulation, in vivo fertilization, and in vivo development. A total of 810 in vitro-matured oocytes were transferred into 14 heifers. Subsequently, 222 embryos (27.3%) were recovered after uterine flushing at Day 7. Based on the number of cleaved embryonic stages, 64.2% developed to the blastocyst stage, which did not differ from the IVP-derived embryos (58.2%). Interestingly, lipid content of IFOT-derived blastocysts did not differ from the fully in vivo-produced embryos, whereas IVP-derived blastocysts showed significantly higher lipid droplet accumulation compared with fully in vivo-derived and IFOT-derived blastocysts (P<0.05). Accordingly, IFOT blastocysts showed significantly higher survival rates after cryopreservation than complete IVP-derived embryos (77% v. 10%), which might be attributed to a lower degree of lipid accumulation. In agreement, transfer of frozen-thawed IFOT blastocysts to synchronized recipients (uterine recipients) resulted in much higher pregnancy rates compared with transfer of IVP-derived blastocysts (42.1 v. 13.8%) but did not differ from frozen-thawed ex vivo blastocysts (52.4%). Of these presumed IFOT pregnancies, 7 went to term, and microsatellite analysis confirmed that 5 calves were indeed derived from IFOT, whereas 2 were caused by fertilization of the follicular recipient's own oocyte after AI. Taken together, IFOT-derived blastocysts closely resemble in vivo-derived blastocysts, confirming earlier suggestions that the ability to develop to the blastocyst stage is already determined in the matured oocyte, whereas the quality in terms of lipid content and survival rate after cryopreservation is affected by the environment thereafter. However, to the best of our knowledge, this is the first study reporting healthy calves after intrafollicular transfer of in vitro-matured oocytes. PMID:25472135

Hoelker, M; Kassens, A; Held, E; Wrenzycki, C; Besenfelder, U; Havlicek, V; Sieme, H; Tesfaye, D; Schellander, K

2014-12-01

100

The roles of wetting liquid in the transfer process of single layer graphene onto arbitrary substrates.  

PubMed

Wet transfer is crucial for most device structures of the proposed applications employing single layer graphene in order to take advantage of the unique physical, chemical, bio-chemical and electrical properties of the graphene. However, transfer methodologies that can be used to obtain continuous film without voids, wrinkles and cracks are limited although film perfectness critically depends on the relative surface tension of wetting liquids on the substrate. We report the importance of wetting liquid in the transfer process with a systematic study on the parameters governing film integrity in single layer graphene grown via chemical vapor deposition. Two different suspension liquids (in terms of polar character) are tested for adequacy of transfer onto SiO2 and hexamethyldisiloxane (HMDS). We found that the relative surface tension of the wetting liquid on the surfaces of the substrate is related to transfer quality. In addition, dimethyl sulfoxide (DMSO) is introduced as a good suspension liquid to HMDS, a mechanically flexible substrate. PMID:24245262

Kim, Ju Hun; Yi, Junghwa; Jin, Hyeong Ki; Kim, Un Jeong; Park, Wanjun

2013-11-01

101

Single mutations that redirect internal proton transfer in the ba3 oxidase from Thermus thermophilus  

PubMed Central

The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound proton pump. Results from earlier studies have shown that with the aa3-type oxidases proton uptake to the catalytic site and “pump site” occur simultaneously. However, with the ba3 oxidase the pump site is loaded before proton transfer to the catalytic site because the proton transfer to the latter is slower than with the aa3 oxidases. In addition, the timing of formation and decay of catalytic intermediates is different in the two types of oxidases. In the present study, we have investigated two mutant ba3 CytcOs in which residues of the proton pathway leading to the catalytic site as well as the pump site were exchanged, Thr312Val and Tyr244Phe. Even though the ba3 CytcO uses only a single proton pathway for transfer of the substrate and “pumped” protons, the amino-acid residue substitutions had distinctly different effects on the kinetics of proton transfer to the catalytic site and the pump site, respectively. The results indicate that the rates of these reactions can be modified independently by replacement of single residues within the proton pathway. Furthermore, the data suggest that the Thr312Val and Tyr244Phe mutations interfere with a structural rearrangement in the proton pathway that is rate limiting for proton transfer to the catalytic site. PMID:24004023

Smirnova, Irina; Chang, Hsin-Yang; von Ballmoos, Christoph; Ädelroth, Pia; Gennis, Robert B.; Brzezinski, Peter

2014-01-01

102

Indoor demonstration of free-space picosecond two-way time transfer on single photon level  

NASA Astrophysics Data System (ADS)

The practical demonstration of an optical two-way time transfer based on single photon signal level has been completed. This approach enables to reach extreme timing stabilities and minimal systematic errors using existing electrooptic technologies. The crucial condition to almost eliminate systematic errors and to reach picosecond time transfer accuracy over free space communication channel is the maximum symmetry in experimental setup. In our indoor experiment we have achieved sub-picosecond precison and 3 ps accuracy. The entire system is compact and relatively simple.

Blazej, Josef; Prochazka, Ivan; Kodet, Jan; Linhart, Pavel

2014-10-01

103

On-demand single-electron transfer between distant quantum dots.  

PubMed

Single-electron circuits of the future, consisting of a network of quantum dots, will require a mechanism to transport electrons from one functional part of the circuit to another. For example, in a quantum computer decoherence and circuit complexity can be reduced by separating quantum bit (qubit) manipulation from measurement and by providing a means of transporting electrons between the corresponding parts of the circuit. Highly controlled tunnelling between neighbouring dots has been demonstrated, and our ability to manipulate electrons in single- and double-dot systems is improving rapidly. For distances greater than a few hundred nanometres, neither free propagation nor tunnelling is viable while maintaining confinement of single electrons. Here we show how a single electron may be captured in a surface acoustic wave minimum and transferred from one quantum dot to a second, unoccupied, dot along a long, empty channel. The transfer direction may be reversed and the same electron moved back and forth more than sixty times-a cumulative distance of 0.25 mm-without error. Such on-chip transfer extends communication between quantum dots to a range that may allow the integration of discrete quantum information processing components and devices. PMID:21938065

McNeil, R P G; Kataoka, M; Ford, C J B; Barnes, C H W; Anderson, D; Jones, G A C; Farrer, I; Ritchie, D A

2011-09-22

104

In vitro development of OPU-derived bovine embryos cultured either individually or in groups with the silk protein sericin and the viability of frozen-thawed embryos after transfer.  

PubMed

The optimization of single-embryo culture conditions is very important, particularly in the in vitro production of bovine embryos using the ovum pick-up (OPU) procedure. The purpose of this study was to examine the development of embryos derived from oocytes obtained by OPU that were cultured either individually or in groups in medium supplemented with or without sericin and to investigate the viability of the frozen-thawed embryos after a direct transfer. When two-cell-stage embryos were cultured either individually or in groups for 7 days in CR1aa medium supplemented with or without 0.5% sericin, the rates of development to blastocysts and freezable blastocysts were significantly lower for the embryos cultured individually without sericin than for the embryos cultured in groups with or without sericin. Moreover, the rate of development to freezable blastocysts of the embryos cultured individually with sericin was significantly higher than that of the embryos cultured without sericin. When the frozen-thawed embryos were transferred directly to recipients, the rates of pregnancy, abortion, stillbirth and normal calving in the recipients were similar among the groups, irrespective of the culture conditions and sericin supplementation. Our findings indicate that supplementation with sericin during embryo culture improves the quality of the embryos cultured individually but not the viability of the frozen-thawed embryos after transfer to recipients. PMID:25488699

Isobe, Tomohiro; Ikebata, Yoshihisa; Do, Lanh Thi Kim; Tanihara, Fuminori; Taniguchi, Masayasu; Otoi, Takeshige

2014-12-01

105

Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques.  

PubMed

The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND's size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques. PMID:25181280

Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

2014-09-26

106

Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques  

NASA Astrophysics Data System (ADS)

The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND’s size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques.

Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

2014-09-01

107

Light-induced heat and mass transfer in a single-component gas in a capillary  

SciTech Connect

A theoretical analysis is presented of light-induced heat and mass transfer in a single-component gas in a capillary tube at arbitrary Knudsen numbers. Surface and collisional mechanisms of transfer are analyzed, due to differences in accommodation coefficient and collision cross section between excited-and ground-state particles, respectively. Analytical expressions for kinetic coefficients characterizing the gas drift and heat transfer in a capillary tube are obtained in the limits of low and high Knudsen numbers. Numerical computations are performed for intermediate Knudsen numbers. Both drift and heat fluxes are determined as functions of the light beam frequency. In the case of an inhomogeneously broadened absorption line, the light-induced fluxes are found to depend not only on the sign, but also on the amount, of light beam detuning from the absorption line center frequency.

Chermyaninov, I. V., E-mail: vladimir.chernyak@usu.ru; Chernyak, V. G.; Vilisova, E. A. [Ural State University (Russian Federation)

2007-10-15

108

Single electron transfer between selectfluor and chloride: A mass spectrometric and theoretical study  

NASA Astrophysics Data System (ADS)

The reaction between 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis-tetrafluoroborate (selectfluor) and chloride has been studied experimentally and modeled computationally at the ab initio levels. Based on the interception experiments by electrospray ionization-mass spectrometry (ESI-MS), it is found that only 5,5-dimethyl-l-pyrroline N-oxide (DMPO) succeeds in trapping the chlorine free radical. This result indicates that the single electron transfer (SET) is likely to occur between selectfluor and chloride. According to the Marcus' theory, the activation and reaction free energies for this electron transfer have been calculated. The theoretical study shows that the electron transfer reaction is both thermodynamically and kinetically beneficial, which is consistent with the experiment.

Zhang, Xiang

2013-10-01

109

Charge transfer dynamics from adsorbates to surfaces with single active electron and configuration interaction based approaches  

NASA Astrophysics Data System (ADS)

We employ wavepacket simulations based on many-body time-dependent configuration interaction (TD-CI), and single active electron theories, to predict the ultrafast molecule/metal electron transfer time scales, in cyano alkanethiolates bonded to model gold clusters. The initial states represent two excited states where a valence electron is promoted to one of the two virtual ?? molecular orbitals localized on the cyanide fragment. The ratio of the two time scales indicate the efficiency of one charge transfer channel over the other. In both our one-and many-electron simulations, this ratio agree qualitatively with each other as well as with the previously reported experimental time scales (Blobner et al., 2012), measured for a macroscopic metal surface. We study the effect of cluster size and the description of electron correlation on the charge transfer process.

Ramakrishnan, Raghunathan; Nest, Mathias

2015-01-01

110

Passive techniques for the enhancement of convective heat transfer in single phase duct flow  

NASA Astrophysics Data System (ADS)

This review presents the main results of the experimental campaign on passive techniques for the enhancement of forced convective single phase heat transfer in ducts, performed in the last years at the Laboratory of the Industrial Engineering Department of the University of Parma by the Applied Physics research group. The research was mainly focused on two passive techniques, widely adopted for the thermal processing of medium and high viscosity fluids, based on wall corrugation and on wall curvature. The innovative compound heat transfer enhancement technique that couples together the effect of wall curvature and of wall corrugation has been investigated as well. The research has been mainly focused on understanding the causal relationship between the heat transfer surface modification and the convection enhancement phenomenon, by accounting the effect of the fluid Prandtl number. The pressure loss penalties were also evaluated. The principal results are presented and discussed.

Rainieri, S.; Bozzoli, F.; Cattani, L.

2014-11-01

111

Single Transition-to-single Transition Polarization Transfer (ST2-PT) in [15N,1H]-TROSY.  

PubMed

This paper describes the use of single transition-to-single transition polarization transfer (ST2-PT) in transverse relaxation-optimized spectroscopy (TROSY), where it affords a [Formula: see text] sensitivity enhancement for kinetically stable amide 15N-1H groups in proteins. Additional, conventional improvements of [15N,1H]-TROSY include that signal loss for kinetically labile 15N-1H groups due to saturation transfer from the solvent water is suppressed with the 'water flip back' technique and that the number of phase steps is reduced to two, which is attractive for the use of [15N,1H]-TROSY as an element in more complex NMR schemes. Finally, we show that the impact of the inclusion of the 15N steady-state magnetization (Pervushin et al., 1998) on the signal-to-noise ratio achieved with [15N,1H]-TROSY exceeds by up to two-fold the gain expected from the gyromagnetic ratios of 1H and 15N. PMID:21136330

Pervushin, K V; Wider, G; Wüthrich, K

1998-08-01

112

LOAD TRANSFER AND MECHANICAL PROPERTIES OF CHEMICALLY DERIVED SINGLE LAYER GRAPHENE REINFORCEMENTS IN POLYMER COMPOSITES  

PubMed Central

We report load transfer and mechanical properties of chemically derived single layer graphene (SLG) as reinforcements in poly (dimethyl) siloxane (PDMS) composites. Mixing single layer graphene in polymers resulted in the marked decrease of the G’ or 2D band intensity due to doping and functionalization. A Raman G mode shift of 11.2 cm?1/% strain in compression and 4.2 cm?1/% strain in tension is reported. An increase in elastic modulus of PDMS by ~42%, toughness by ~39%, damping capability by ~673%, and strain energy density of ~43% by the addition of 1 wt. % SLG in PDMS is reported. PMID:23196792

Xu, Peng; Loomis, James; Panchapakesan, Balaji

2013-01-01

113

Electron Transfer-Based Single Molecule Fluorescence as a Probe for Nano-Environment Dynamics  

PubMed Central

Electron transfer (ET) is one of the most important elementary processes that takes place in fundamental aspects of biology, chemistry, and physics. In this review, we discuss recent research on single molecule probes based on ET. We review some applications, including the dynamics of glass-forming systems, surface binding events, interfacial ET on semiconductors, and the external field-induced dynamics of polymers. All these examples show that the ET-induced changes of fluorescence trajectory and lifetime of single molecules can be used to sensitively probe the surrounding nano-environments. PMID:24496314

Chen, Ruiyun; Wu, Ruixiang; Zhang, Guofeng; Gao, Yan; Xiao, Liantuan; Jia, Suotang

2014-01-01

114

Heat transfer characteristics of a single circular air jet impinging on a concave hemispherical shell  

NASA Technical Reports Server (NTRS)

An experimental study was made of the local and average heat-transfer characteristics of a single turbulent air jet impinging on the concave surface of a hemisphere. Correlations were developed for expressing the effects of a number of dimensionless variables on the local and average Nusselt numbers. Results of the present study are compared with those from a similar study concerning a concave surface of a semicylindrical shell.

Livingood, J. N. B.; Gauntner, J. W.

1973-01-01

115

Distance dependence of the energy transfer rate from a single semiconductor nanostructure to graphene.  

PubMed

The near-field Coulomb interaction between a nanoemitter and a graphene monolayer results in strong Förster-type resonant energy transfer and subsequent fluorescence quenching. Here, we investigate the distance dependence of the energy transfer rate from individual, (i) zero-dimensional CdSe/CdS nanocrystals and (ii) two-dimensional CdSe/CdS/ZnS nanoplatelets to a graphene monolayer. For increasing distances d, the energy transfer rate from individual nanocrystals to graphene decays as 1/d(4). In contrast, the distance dependence of the energy transfer rate from a two-dimensional nanoplatelet to graphene deviates from a simple power law but is well described by a theoretical model, which considers a thermal distribution of free excitons in a two-dimensional quantum well. Our results show that accurate distance measurements can be performed at the single particle level using graphene-based molecular rulers and that energy transfer allows probing dimensionality effects at the nanoscale. PMID:25607231

Federspiel, François; Froehlicher, Guillaume; Nasilowski, Michel; Pedetti, Silvia; Mahmood, Ather; Doudin, Bernard; Park, Serin; Lee, Jeong-O; Halley, David; Dubertret, Benoît; Gilliot, Pierre; Berciaud, Stéphane

2015-02-11

116

Maternal diabetes impairs gastrulation and insulin and IGF-I receptor expression in rabbit blastocysts.  

PubMed

Women with type 1 diabetes are subfertile. Diabetes negatively affects pregnancy by causing early miscarriage and poor prenatal outcomes. In this study we examine consequences of maternal type 1 diabetes on early embryo development, metabolic gene expression, and the pattern of insulin receptor (IR) and IGF-I receptor (IGF-IR) distribution in rabbit blastocysts. In female rabbits, type 1 diabetes was induced by alloxan treatment. Six-day-old blastocysts were recovered and assessed for receptor distribution and metabolic gene expression. In vitro culture of blastocysts was performed in medium containing 1 mm, 10 mm, or 25 mm glucose, simulating normo- and hyperglycemic developmental condition in vitro. The fertility rate of the diabetic rabbits clearly mirrored subfertility with a drop in blastocyst numbers by 40% (13.3 blastocysts in diabetic vs. 21.9 in control females). In blastocysts onset and progression of gastrulation was delayed and expression of IR and IGF-IR and their metabolic target genes (hexokinase, phosphoenolpyruvate carboxykinase), both in vivo and in vitro, was down-regulated. The amount of apoptotic cells in the embryonic disc was increased, correlating closely with the reduced transcription of the bcl-x(L) gene. Blastocyst development is clearly impaired by type 1 diabetes during early pregnancy. Insulin-stimulated metabolic genes and IR and IGF-IR are down-regulated, resulting in reduced insulin and IGF sensitivity and a delay in development. Dysregulation of the IGF system and embryonic glucose metabolism are potential reasons for diabetogenous subfertility and embryopathies and start as soon as during the first days of life. PMID:20631000

Ramin, Nicole; Thieme, René; Fischer, Sünje; Schindler, Maria; Schmidt, Thomas; Fischer, Bernd; Navarrete Santos, Anne

2010-09-01

117

Conjugate heat transfer measurements with single-phase and water flow boiling in a single-side heated monoblock flow channel  

Microsoft Academic Search

Optimized and robust designs of one-side heated plasma-facing components and other heat flux removal components are dependent on conjugate heat transfer. In the present case, the conjugate heat transfer involved measuring the local distributions of the inside wall temperature and heat flux in a single-side heated monoblock flow channel with: (1) peripheral (radial and circumferential) heat transfer; and, (2) coupled

Ronald D. Boyd; Hongtao Zhang

2006-01-01

118

Requirement of inner cell mass for efficient chorionic gonadotrophin secretion by blastocysts of common marmosets (Callithrix jacchus).  

PubMed

The role of the inner cell mass in the induction of chorionic gonadotrophin synthesis and secretion by the trophoblast of the peri-implantation primate blastocyst was studied in common marmoset monkeys. An in vitro system for the culture of blastocysts commencing with blastocysts collected 8 days after conception was developed. Chorionic gonadotrophin measured in the spent culture fluid was first detected in most blastocysts after 3 or 4 days (day 11 or 12) of culture at a time equivalent to implantation in vitro. Initial secretion of chorionic gonadotrophin coincided with development of parietal endoderm and histological appearance of syncytiotrophoblast in the polar trophoblast. Little chorionic gonadotrophin was secreted by blastocysts with a poorly developed, or absent, inner cell mass. Mural trophoblast removed from blastocysts after 2 days of culture (day 10) grew in vitro as a unilaminar vesicle but failed to secrete significant amounts of chorionic gonadotrophin. However, mural trophoblast from older blastocysts (days 13 and 14) after chorionic gonadotrophin secretion had commenced continued to secrete chorionic gonadotrophin, with trophoblast from day 14 blastocysts secreting significantly more than that from day 13. It was concluded from these studies that while mural trophoblast from marmoset blastocysts will proliferate in vitro in the absence of an inner cell mass, efficient induction of chorionic gonadotrophin secretion requires the presence of the inner cell mass or its derivatives. Once chorionic gonadotrophin secretion has commenced, secretion will continue in the absence of the inner cell mass. PMID:8501702

Summers, P M; Taylor, C T; Miller, M W

1993-03-01

119

Metal-etching-free direct delamination and transfer of single-layer graphene with a high degree of freedom.  

PubMed

A method of graphene transfer without metal etching is developed to minimize the contamination of graphene in the transfer process and to endow the transfer process with a greater degree of freedom. The method involves direct delamination of single-layer graphene from a growth substrate, resulting in transferred graphene with nearly zero Dirac voltage due to the absence of residues that would originate from metal etching. Several demonstrations are also presented to show the high degree of freedom and the resulting versatility of this transfer method. PMID:25104479

Yang, Sang Yoon; Oh, Joong Gun; Jung, Dae Yool; Choi, HongKyw; Yu, Chan Hak; Shin, Jongwoo; Choi, Choon-Gi; Cho, Byung Jin; Choi, Sung-Yool

2015-01-01

120

Qubit fidelity of a single atom transferred among the sites of a ring optical lattice  

NASA Astrophysics Data System (ADS)

We demonstrate the transfer of a single atom in a ring optical lattice with the aid of an auxiliary moving tweezer and investigate the influences on fidelity of the qubit encoded in the atom. When the tweezer has deeper trap depth and moves across the lattice, it is observed that an atom in one site follows the movement. The transfer efficiency of one atom to the destination site reaches up to 95%. This scheme is suitable for scalable quantum registers because of no influence on the other sites. We obtain atomic qubit fidelity during the transfer process by using quantum state tomography. Extracted fidelity indicates that the eigenstate is well preserved, while the superposition state is influenced. In combination with spin-echo measurement, dephasing mechanisms in this process are analyzed and discussed in detail. Loss of qubit fidelity is found to result from heating effects induced by this process and pointing instabilities of the trap laser. Our results pave the way for quantum computation with single atoms trapped in a scalable optical lattice.

Yu, Shi; Xu, Peng; Liu, Min; He, Xiaodong; Wang, Jin; Zhan, Mingsheng

2014-12-01

121

Ooplast transfer of triploid pronucleus zygote improve reconstructed human-goat embryonic development.  

PubMed

Poor development of the interspecies somatic cell nuclear transfer (iSCNT) embryos was due to nuclear-mitochondrial incompatibility. In humans, it has been known that ooplast transfer (OT) could support normal fertilization, the development of embryos and prevents the transmission of mtDNA disease. To investigate whether OT could support development of the iSCNT embryos, the ooplast of Triploid Pronucleus (3PN) zygote which would be discarded in IVF lab was transferred into the enucleated goat oocytes to construct humanized iSCNT embryos in our study. The results showed the 3PN-OT could significantly improve the early development of humanized iSCNT embryos. The percentage of blastocyst development of OT group was also higher than that of the control group. Interestingly, the morphology of some OT-iSCNT blastocysts was similar to normal human blastocysts in vitro fertilization, while the morphology of iSCNT blastocysts from control group was similar to goat blastocysts. Importantly, the pluripotent marker Oct4 of the OT-iSCNT blastocyst was expressed stronger than that of the control group. These results suggested that 3PN-OT could improve the developmental potency of human iSCNT embryos and would facilitate establishing ESCs from iSCNT blastocysts. PMID:25419417

Yao, Ling; Wang, Pu; Liu, Jia; Chen, Jianquan; Tang, Hailiang; Sha, Hongying

2014-01-01

122

Ooplast transfer of triploid pronucleus zygote improve reconstructed human-goat embryonic development  

PubMed Central

Poor development of the interspecies somatic cell nuclear transfer (iSCNT) embryos was due to nuclear-mitochondrial incompatibility. In humans, it has been known that ooplast transfer (OT) could support normal fertilization, the development of embryos and prevents the transmission of mtDNA disease. To investigate whether OT could support development of the iSCNT embryos, the ooplast of Triploid Pronucleus (3PN) zygote which would be discarded in IVF lab was transferred into the enucleated goat oocytes to construct humanized iSCNT embryos in our study. The results showed the 3PN-OT could significantly improve the early development of humanized iSCNT embryos. The percentage of blastocyst development of OT group was also higher than that of the control group. Interestingly, the morphology of some OT-iSCNT blastocysts was similar to normal human blastocysts in vitro fertilization, while the morphology of iSCNT blastocysts from control group was similar to goat blastocysts. Importantly, the pluripotent marker Oct4 of the OT-iSCNT blastocyst was expressed stronger than that of the control group. These results suggested that 3PN-OT could improve the developmental potency of human iSCNT embryos and would facilitate establishing ESCs from iSCNT blastocysts. PMID:25419417

Yao, Ling; Wang, Pu; Liu, Jia; Chen, Jianquan; Tang, Hailiang; Sha, Hongying

2014-01-01

123

Charge transfer processes and ultraviolet induced absorption in Yb:YAG single crystal laser materials  

NASA Astrophysics Data System (ADS)

Charge transfer (CT) transitions and UV induced color centers in Yb:YAG single crystals have been investigated. A simultaneous pair formation of a stable Yb2+ ion and a hole related (O-) color center (hole polaron) are observed through a CT-process. Slightly different types of hole related color centers are formed in Yb:YAG crystals containing small levels of iron impurities. Furthermore, excitation spectroscopy on the UV irradiated Yb:YAG samples could confirm an energy transfer process between Yb3+ and Yb2+ ions. The findings are important for an increased knowledge of the physical loss mechanisms observed in Yb-doped laser materials, such as the nonlinear decay process in Yb:YAG crystals as well as the photodarkening phenomenon in Yb-doped fiber lasers.

Rydberg, S.; Engholm, M.

2013-06-01

124

Single-stage reconstruction of flexor tendons with vascularized tendon transfers.  

PubMed

The reconstruction of finger flexor tendons with vascularized flexor digitorum superficialis (FDS) tendon grafts (flaps) based on the ulnar vessels as a single stage is not a popular technique. We reviewed 40 flexor tendon reconstructions (four flexor pollicis longus and 36 finger flexors) with vascularized FDS tendon grafts in 38 consecutive patients. The donor tendons were transferred based on the ulnar vessels as a single-stage procedure (37 pedicled flaps, three free flaps). Four patients required composite tendon and skin island transfer. Minimum follow-up was 12 months, and functional results were evaluated using a total active range of motion score. Multiple linear regression analysis was performed to evaluate the factors that could be associated with the postoperative total active range of motion. The average postoperative total active range of motion (excluding the thumbs) was 178.05° (SD 50°). The total active range of motion was significantly lower for patients who were reconstructed with free flaps and for those who required composite tendon and skin island flap. Age, right or left hand, donor/motor tendon and pulley reconstruction had no linear effect on total active range of motion. Overall results were comparable with a published series on staged tendon grafting but with a lower complication rate. Vascularized pedicled tendon grafts/flaps are useful in the reconstruction of defects of finger flexor tendons in a single stage, although its role in the reconstructive armamentarium remains to be clearly established. PMID:24436359

Cavadas, P C; Pérez-García, A; Thione, A; Lorca-García, C

2014-01-15

125

Conditional deletion of MSX homeobox genes in the uterus inhibits blastocyst implantation by altering uterine receptivity  

PubMed Central

An effective bidirectional communication between an implantation-competent blastocyst and the receptive uterus is a prerequisite for mammalian reproduction. The blastocyst will implant only when this molecular cross-talk is established. Here we show that the muscle segment homeobox gene (Msh) family members Msx1 and Msx2, which are two highly conserved genes critical for epithelial-mesenchymal interactions during development, also play crucial roles in embryo implantation. Loss of Msx1/Msx2 expression correlates with altered uterine luminal epithelial cell polarity and affects E-cadherin/?-catenin complex formation through the control of Wnt5a expression. Application of Wnt5a in vitro compromised blastocyst invasion and trophoblast outgrowth on cultured uterine epithelial cells. The finding that Msx1/Msx2 genes are critical for conferring uterine receptivity and readiness to implantation could have clinical significance, because compromised uterine receptivity is a major cause of pregnancy failure in IVF programs. PMID:22100262

Daikoku, Takiko; Cha, Jeeyeon; Sun, Xiaofei; Tranguch, Susanne; Xie, Huirong; Fujita, Tomoko; Hirota, Yasushi; Lydon, John; DeMayo, Francesco; Maxson, Robert; Dey, Sudhansu K.

2011-01-01

126

Structural Variability of Nucleosomes Detected by Single-Pair Forster Resonance Energy Transfer: Histone Acetylation, Sequence Variation, and Salt Effects  

E-print Network

Structural Variability of Nucleosomes Detected by Single-Pair Fo¨rster Resonance Energy Transfer¨rster resonance energy transfer (spFRET) measurements of the distance between fluorescently labeled bases detuned detection" (D3 ). This permits the separation of subpopulations in the samples even for the low

Langowski, Jörg

127

Membrane conductance in trained and untrained subjects using either steady state or single breath measurements of NO transfer  

Microsoft Academic Search

The aim of this work was to define the relationship between membrane conductance for NO (Dm) and physical activity by using either the steady state NO transfer (TLNOSS) or the single breath method (TLNOSB), making the hypothesis that NO transfer is only limited by the membrane. Alterations in TLNOSS with lung volume during tidal ventilation were measured in six subjects

Stéphane N. Glénet; Claire M. M. de Bisschop; Rim Dridi; Hervé J. P. Guénard

2006-01-01

128

COBRA-SFS predictions of single assembly spent fuel heat transfer data  

SciTech Connect

The study reported here is one of several efforts to evaluate and qualify the COBRA-SFS computer code for use in spent fuel storage system thermal analysis. The ability of COBRA-SFS to predict the thermal response of two single assembly spent fuel heat transfer tests was investigated through comparisons of predictions with experimental test data. From these comparisons, conclusions regarding the computational treatment of the physical phenomena occurring within a storage system can be made. This objective was successfully accomplished as reasonable agreement between predictions and data were obtained for the 21 individual test cases of the two experiments.

Lombardo, N.J.; Michener, T.E.; Wheeler, C.L.; Rector, D.R.

1986-04-01

129

Expression of stemness markers in mouse parthenogenetic-diploid blastocysts is influenced by slight variation of activation protocol adopted.  

PubMed

The importance of obtaining stem cells through alternative methods has increased progressively in the recent years due to the potential role that embryonic stem (ES) cells play in the field of regenerative medicine. In this regard, generation of parthenogenetic blastocysts allows the production of ethic-free ES cells without the need to manipulate normal embryos. Our work was aimed at clarifying whether variations in the method adopted to generate diploid parthenogenetic blastocysts could determine differences in the quality of blastocysts produced. In vitro development of mouse oocytes activated with three protocols, using Sr2+ and cytochalasin for different time, was compared with that of in vivo fertilized embryos. We have evaluated the efficiency of blastocyst formation and analysed the expression pattern of the stemness markers OCT4, CDX2, and NANOG. Our results indicate that the yield of diploid parthenogenotes and the segregation of the stemness marker OCT4 in the developing blastocyst are influenced by the parthenogenetic protocol adopted. Particularly, even if all methods tested allowed the production of blastocysts in vitro, the correct segregation of OCT4 occurred only in blastocysts developed from oocytes concomitantly treated for 4 h with Sr2+ and cytochalasin D. Our results indicate that the protocol employed to develop parthenogenetic blastocysts in vitro affects the quality of cells in the inner cell mass. PMID:20376706

Bianchi, Enrica; Geremia, Raffaele; Sette, Claudio

2010-07-01

130

Controlling intramolecular hydrogen transfer in a porphycene molecule with single atoms or molecules located nearby.  

PubMed

Although the local environment of a molecule can play an important role in its chemistry, rarely has it been examined experimentally at the level of individual molecules. Here we report the precise control of intramolecular hydrogen-transfer (tautomerization) reactions in single molecules using scanning tunnelling microscopy. By placing, with atomic precision, a copper adatom close to a porphycene molecule, we found that the tautomerization rates could be tuned up and down in a controlled fashion, surprisingly also at rather large separations. Furthermore, we extended our study to molecular assemblies in which even the arrangement of the pyrrolic hydrogen atoms in the neighbouring molecule influences the tautomerization reaction in a given porphycene, with positive and negative cooperativity effects. Our results highlight the importance of controlling the environment of molecules with atomic precision and demonstrate the potential to regulate processes that occur in a single molecule. PMID:24345945

Kumagai, Takashi; Hanke, Felix; Gawinkowski, Sylwester; Sharp, John; Kotsis, Konstantinos; Waluk, Jacek; Persson, Mats; Grill, Leonhard

2014-01-01

131

Quick Cooling and Filling Through a Single Port for Cryogenic Transfer Operations  

NASA Technical Reports Server (NTRS)

Improved technology for the efficient transfer of cryogens is needed for future on-orbit fueling and remote Lunar/Mars operations. The cooling and filling of a liquid nitrogen (LN2) test vessel through a single port were investigated in a series of experiments. A new 'in-space' transfer tube design concept was used to demonstrate the ability to quickly cool and load cryogens through a single feed-through connection. Three different fill tube configurations with three different diameters were tested. The tubes providing the quickest cooldown time and the quickest fill time for the test article tank were determined. The results demonstrated a clear trade-off between cooling time and filling time for the optimum tube design. This experimental study is intended to improve technology for future flight tank designs by reducing fill system size, complexity, heat leak rate, and operations time. These results may be applied to Space Shuttle Power Reactant Storage and Distribution (PRSD) System upgrades and other future applications. Further study and experimental analysis for optimization of the fill tube design are in progress.

Jones, J. R.; Fesmire, James E.; MacDowell, L. G. (Technical Monitor)

2001-01-01

132

Synthesis, characterization, and photoinduced electron transfer in functionalized single wall carbon nanohorns.  

PubMed

Single-wall carbon nanohorns (SWNHs) are a new class of material that is closely related to single-wall carbon nanotubes. Here, we describe the synthesis and characterization of a series of SWNHs functionalized with ethylene glycol chains and porphyrins. Functionalization of carbon nanohorns has been achieved using two different synthetic protocols: (1) direct attack of a free amino group on the nanohorn sidewalls (nucleophilic addition) and (2) amidation reaction of the carboxylic functions in oxidized nanohorns. The nanohorn derivatives have been characterized by a combination of several techniques, and the electronic properties of the porphyrin/nanohorn assemblies (SWNH/H2P) have been investigated by electrochemistry, spectroelectrochemistry, and a series of steady-state and time-resolved spectroscopy. The cyclic voltammetry curve of nanohorn/porphyrin conjugate 6 showed a continuum of faradic and pseudocapacitive behavior, which is associated with multiple-electron transfers to and from the SWNHs. Superimposed on such a pseudocapacitive current, the curve also displays three discrete reduction peaks at -2.26, -2.57, and -2.84 V and an oxidation peak at 1.12 V (all attributed to the porphyrin moiety). Steady-state and time-resolved fluorescence demonstrated a quenching of the fluorescence of the porphyrin in SWNH/H2P conjugates 5 and 6 compared to the reference free base porphyrin. Transient absorption spectra permitted the electron-transfer process between the porphyrins and the carbon nanostructures to be highlighted. PMID:17343379

Cioffi, Carla; Campidelli, Stéphane; Sooambar, Chloé; Marcaccio, Massimo; Marcolongo, Gabriele; Meneghetti, Moreno; Paolucci, Demis; Paolucci, Francesco; Ehli, Christian; Rahman, G M Aminur; Sgobba, Vito; Guldi, Dirk M; Prato, Maurizio

2007-04-01

133

Single PWR spent fuel assembly heat transfer data for computer code evaluations  

SciTech Connect

The descriptions and results of two separate heat transfer tests designed to investigate the dry storage of commercial PWR spent fuel assemblies are presented. Presented first are descriptions and selected results from the Fuel Temperature Test performed at the Engine Maintenance and Disassembly facility on the Nevada Test Site. An actual spent fuel assembly from the Turkey Point Unit Number 3 Reactor with a decay heat level of 1.17 KW, was installed vertically in a test stand mounted canister/liner assembly. The boundary temperatures were controlled and the canister backfill gases were alternated between air, helium and vacuum to investigate the primary heat transfer mechanisms of convection, conduction and radiation. The assembly temperature profiles were experimentally measured using installed thermocouple instrumentation. Also presented are the results from the Single Assembly Heat Transfer Test designed and fabricated by Allied General Nuclear Services, under contract to the Department of Energy, and ultimately conducted by the Pacific Northwest Laboratory. For this test, an electrically heated 15 x 15 rod assembly was used to model a single PWR spent fuel assembly. The electrically heated model fuel assembly permitted various ''decay heat'', levels to be tested; 1.0 KW and 0.5 KW were used for these tests. The model fuel assembly was positioned within a prototypic fuel tube and in turn placed within a double-walled sealed cask. The complete test assembly could be positioned at any desired orientation (horizontal, vertical, and 25/sup 0/ from horizontal for the present work) and backfilled as desired (air, helium, or vacuum). Tests were run for all combinations of ''decay heat,'' backfill, and orientation. Boundary conditions were imposed by temperature controlled guard heaters installed on the cask exterior surface.

Bates, J.M.

1986-01-01

134

A model of groundwater seepage and heat transfer for single-well ground source heat pump systems  

Microsoft Academic Search

In China, for the limitation of land, many buildings intending to utilize ground source heat pump systems install “single-well” systems, which drill only one well for both the pumping and reinjection of the groundwater. A model of groundwater seepage and heat transfer for single-well ground source heat pump systems has been established and validated against the experiment conducted in Denmark.

Long Ni; Haorong Li; Yiqiang Jiang; Yang Yao; Zuiliang Ma

2011-01-01

135

Correlation of developmental differences of nuclear transfer embryos cells to the methylation profiles of nuclear transfer donor cells in Swine.  

PubMed

Methylation of DNA is the most commonly studied epigenetic mechanism of developmental competence and somatic cell nuclear transfer (SCNT). Previous studies of epigenetics and the SCNT procedures have examined the effects of different culture media on donor cells and reconstructed embryos, and the methylation status of specific genes in the fetus or live offspring. Here we used a microarray based approach to identify the methylation profiles of SCNT donor cells including three clonal porcine fetal fibroblast-like cell sublines and adult somatic cells selected from kidney and mammary tissues. The methylation profiles of the donor cells were then analyzed with respect to their ability to direct development to the blastocyst stage after nuclear transfer. Clonal cell lines A2, A7 and A8 had blastocyst rates of 11.7%(a), 16.7%(ab) and 20.0%(b), respectively ((ab) p < 0.05). Adult somatic cells included kidney, mammary (large), and mammary (small) also had different blastocyst rates (ab p < 0.05) of 4.2% (a), 10.7% (ab) and 18.3% (b), respectively. For clonal donor cells and for adult somatic cell groups the donor cells with the highest blastocyst rates also had methylation profiles with the lowest similarity to the methylation profiles of the in vivo-produced blastocysts. Conversely, the donor cells with the lowest blastocyst rates had methylation profiles with the highest similarity to the methylation profiles of the in vivo-produced blastocysts. Our findings show there is an inverse correlation to the similarity of the methylation profiles of the donor cells and the in vivo-produced embryos, and to the blastocyst rates following SCNT. PMID:17965590

Bonk, Aaron J; Cheong, Hee-Tae; Li, Rongfeng; Lai, Liangxue; Hao, Yanhong; Liu, Zhonghua; Samuel, Melissa; Fergason, Emily A; Whitworth, Kristin M; Murphy, Clifton N; Antoniou, Eric; Prather, Randall S

2007-09-01

136

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo)  

E-print Network

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo 19 July 2005; accepted 30 October 2005 Abstract Embryo transfer (ET) to recipient females of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts

Engelhardt, John F.

137

Transgenesis by means of Blastocyst-Derived Embryonic Stem Cell Lines  

Microsoft Academic Search

This study demonstrates that blastocyst-derived embryonic stem cells (ED cells) can be used as a vehicle for transgenesis. The method is nearly as efficient as other methods, and the introduced neomycin phosphotransferase (neo) gene is stably transmitted through several generations with no apparent loss in G418 resistance. An important factor contributing to the efficiency of this process is the rigorous

Achim Gossler; Thomas Doetschman; Reinhard Korn; Edgar Serfling; Rolf Kemler

1986-01-01

138

Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro  

Microsoft Academic Search

We describe the derivation of pluripotent embryonic stem (ES) cells from human blastocysts. Two diploid ES cell lines have been cultivated in vitro for extended periods while maintaining expression of markers characteristic of pluripotent primate cells. Human ES cells express the transcription factor Oct-4, essential for development of pluripotential cells in the mouse. When grafted into SCID mice, both lines

Benjamin E. Reubinoff; Chui-Yee Fong; Alan Trounson; Ariff Bongso; Martin F. Pera

2000-01-01

139

Apoptosis affects integration frequency: Adult stem cells injected in blastocysts show high caspase-3 activity  

Microsoft Academic Search

Chimeric organisms are commonly generated by injecting stem cells into blastocysts. Embryonic stem cells injected into the blastocoel cavity participate in the further development of the embryo. Adult stem cells have also been used in injection experiments to study their potential plasticity.In this study we focused on the early fate of injected human adult hematopoietic stem cells (HSCs). HSCs were

S. Koestenbauer; P. Vanderzwalmen; A. Hammer; L. Schoonjans; S. Danloy; H. Zech; G. Dohr; N. H. Zech

2007-01-01

140

Zonula occludens-1 (ZO-1) is involved in morula to blastocyst transformation in the mouse.  

PubMed

It is unknown whether or not tight junction formation plays any role in morula to blastocyst transformation that is associated with development of polarized trophoblast cells and fluid accumulation. Tight junctions are a hallmark of polarized epithelial cells and zonula occludens-1 (ZO-1) is a known key regulator of tight junction formation. Here we show that ZO-1 protein is first expressed during compaction of 8-cell embryos. This stage-specific appearance of ZO-1 suggests its participation in morula to blastocyst transition. Consistent with this idea, we demonstrate that ZO-1 siRNA delivery inside the blastomeres of zona-weakened embryos using electroporation not only knocks down ZO-1 gene and protein expressions, but also inhibits morula to blastocyst transformation in a concentration-dependent manner. In addition, ZO-1 inactivation reduced the expression of Cdx2 and Oct-4, but not ZO-2 and F-actin. These results provide the first evidence that ZO-1 is involved in blastocyst formation from the morula by regulating accumulation of fluid and differentiation of nonpolar blastomeres to polar trophoblast cells. PMID:18423437

Wang, Hehai; Ding, Tianbing; Brown, Naoko; Yamamoto, Yasutoshi; Prince, Lawrence S; Reese, Jeff; Paria, B C

2008-06-01

141

Ultrastructural characterization of in vivo-produced ovine morulae and blastocysts.  

PubMed

Summary The ultrastructure of in vivo-produced ovine embryos, at the morula, early blastocyst and late blastocyst stages, was evaluated using transmission electron microscopy. Embryonic cells were characterized by the presence of intact intercellular junctions, numerous mitochondria, smooth endoplasmic reticulum cisternae and light vesicles. Polyribosomes, rough endoplasmic reticulum cisternae, secondary lysosomes, Golgi complexes and lipid droplets were also observed in the cytoplasm. The nucleus was well defined and organized, with an intact envelope rich in nuclear pore complexes, and one or more reticular nucleoli. Microvilli were present in external blastomeres of morulae and became more abundant in trophectoderm cells of early and late blastocysts. Light vesicles seemed to be associated with small cisternae of Golgi and endoplasmic reticulum origin. These cisternae fused and created light vesicles with engulfed heterogeneous cytosolic structures, small cisternae and vesicles. Their labile membrane enabled them to rapidly coalesce into medium-sized vesicles that began to engulf mitochondria and lipid droplets, forming giant vacuoles mostly filled with fat. Incomplete matured secretory vesicles were observed to exocytose into the perivitelline space of morulae, whereas fully matured secretory vesicles appeared only in trophectoderm cells, being exocytosed into the blastocoelic cavity. These observations suggested that these endoplasmic-/Golgi-derived vesicles behave as active autophagic organelles presenting probably a maturation process from compact morulae to blastocyst. PMID:25076424

Bettencourt, E M V; Bettencourt, C M V; E Silva, J N Chagas; Ferreira, P; Oliveira, E; Romão, R; Rocha, A; Sousa, M

2014-07-30

142

ISOLATION AND CHARACTERIZATION OF PORCINE VISCERAL ENDODERM CELL LINES DERIVED FROM IN VIVO 11-DAY BLASTOCYSTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two porcine cell lines of yolk-sac visceral endoderm, designated PE-1 and PE-2, were derived from in vivo 11-day porcine blastocysts that were either ovoid (PE-1) or at the early tubular stage of elongation (PE-2). Primary and secondary culture of cell lines was done on STO feeder cells. The PE-1 ...

143

Messenger RNAs in metaphase II oocytes correlate with successful embryo development to the blastocyst stage.  

PubMed

The mRNAs accumulated in oocytes provide support for embryo development until embryo genomic activation. We hypothesized that the maternal mRNA stock present in bovine oocytes is associated with embryo development until the blastocyst stage. To test our hypothesis, we analyzed the transcriptome of the oocyte and correlated the results with the embryo development. Our goal was to identify genes expressed in the oocyte that correlate with its ability to develop to the blastocyst stage. A fraction of oocyte cytoplasm was biopsied using micro-aspiration and stored for further expression analysis. Oocytes were activated chemically, cultured individually and classified according to their capacity to develop in vitro to the blastocyst stage. Microarray analysis was performed on mRNA extracted from the oocyte cytoplasm fractions and correlated with its ability to develop to the blastocyst stage (good quality oocyte) or arrest at the 8-16-cell stage (bad quality oocyte). The expression of 4320 annotated genes was detected in the fractions of cytoplasm that had been collected from oocytes matured in vitro. Gene ontology classification revealed that enriched gene expression of genes was associated with certain biological processes: 'RNA processing', 'translation' and 'mRNA metabolic process'. Genes that are important to the molecular functions of 'RNA binding' and 'translation factor activity, RNA binding' were also enriched in oocytes. We identified 29 genes with differential expression between the two groups of oocytes compared (good versus bad quality). The content of mRNAs expressed in metaphase II oocytes influences the activation of the embryonic genome and enables further develop to the blastocyst stage. PMID:23046986

Biase, Fernando Henrique; Everts, Robin Edward; Oliveira, Rosane; Santos-Biase, Weruska Karyna Freitas; Fonseca Merighe, Giovana Krempel; Smith, Lawrence Charles; Martelli, Lúcia; Lewin, Harris; Meirelles, Flávio Vieira

2014-02-01

144

Timing of cell division in human cleavage-stage embryos is linked with blastocyst formation and quality.  

PubMed

Noninvasive markers of embryo quality are being sought to improve IVF success. The present study aimed to discover possible associations between embryo division kinetics in the cleavage stage, the subsequent ability of human embryos to reach the blastocyst stage and the resulting blastocyst morphology. A retrospective cohort study analysed 834 embryos from 165 oocyte donation couples using a time-lapse monitoring system that allowed the recording of the exact timings for key events related to embryo development. Timing parameters were categorized into four quartiles. The probability of an embryo developing to a blastocyst was linked to a strict chronology of development. To further evaluate the relationships between these morphokinetic parameters and subsequent blastocyst formation, the ensuing blastocyst morphology was compared with a viability score based on a hierarchical classification of the cleavage-stage morphokinetic parameters. It is concluded that the kinetics of early embryo development and the potential for human embryos to develop to the blastocyst stage on day 5 are closely related and that time-lapse-based evaluation of the exact timing of early events in embryo development is a promising tool for the prediction of blastocyst formation and quality according to the proposed model. PMID:22877944

Cruz, María; Garrido, Nicolás; Herrero, Javier; Pérez-Cano, Inmaculada; Muñoz, Manuel; Meseguer, Marcos

2012-10-01

145

Heavy ion linear energy transfer measurements during single event upset testing of electronic devices  

SciTech Connect

A heavy ion beam diagnostic system installed at the Brookhaven Single Event Upset Test Facility is described. Calibration of the system with the help of {alpha}-particles, essential for linear energy transfer (LET) measurements, is discussed. Measured LET values for 20 different ions, including {sup 7}Li, {sup 9}B, {sup 12}C, {sup 16}O, {sup 19}F, {sup 28}Si, {sup 32}S, {sup 35}Cl, {sup 40}Ca, {sup 45}Sc, {sup 48}Ti, {sup 56}Fe, {sup 58}Ni, {sup 63}Cu, {sup 74}Ge, {sup 79}Br, {sup 107}Ag, {sup 127}I, {sup 197}Au, and {sup 235}U, with energies between 0.5 and 8.5 MeV/AMU but not exceeding 400 MeV for the heaviest ions, are presented in both graphical and numerical forms. Results are compared to predictions of the TRIM-90 simulation program, with an average difference between the measured and calculated values of 2 {+-} 6%.

Zajic, V.; Thieberger, P. [Brookhaven National Lab., Upton, NY (United States)] [Brookhaven National Lab., Upton, NY (United States)

1999-02-01

146

Photoinduced charge transfer and acetone sensitivity of single-walled carbon nanotube-titanium dioxide hybrids.  

PubMed

The unique physical and chemical properties of single-walled carbon nanotubes (SWNTs) make them ideal building blocks for the construction of hybrid nanostructures. In addition to increasing the material complexity and functionality, SWNTs can probe the interfacial processes in the hybrid system. In this work, SWNT-TiO2 core/shell hybrid nanostructures were found to exhibit unique electrical behavior in response to UV illumination and acetone vapors. By experimental and theoretical studies of UV and acetone sensitivities of different SWNT-TiO2 hybrid systems, we established a fundamental understanding on the interfacial charge transfer between photoexcited TiO2 and SWNTs as well as the mechanism of acetone sensing. We further demonstrated a practical application of photoinduced acetone sensitivity by fabricating a microsized room temperature acetone sensor that showed fast, linear, and reversible detection of acetone vapors with concentrations in few parts per million range. PMID:23734594

Ding, Mengning; Sorescu, Dan C; Star, Alexander

2013-06-19

147

Enhanced enzyme activity through electron transfer between single-walled carbon nanotubes and horseradish peroxidase  

PubMed Central

Better understanding of electron transfer (ET) taking place at the nano-bio interface can guide design of more effective functional materials used in fuel cells, biosensors, and medical devices. Single-walled carbon nanotube (SWCNT) coupled with biological enzymes serves as a model system for studying the ET mechanism, as demonstrated in the present study. SWCNT enhanced the activity of horseradish peroxidase (HRP) in the solution-based redox reaction by binding to HRP at a site proximate to the enzyme’s activity center and participating in the ET process. ET to and from SWCNT was clearly observable using near-infrared spectroscopy. The capability of SWCNT in receiving electrons and the direct attachment of HRP to the surface of SWCNT strongly affected the enzyme activity due to the direct involvement of SWCNT in ET. PMID:22228910

Ren, Lei; Yan, Dong; Zhong, Wenwan

2011-01-01

148

Single embryo transfer: the role of natural cycle/minimal stimulation IVF in the future.  

PubMed

There are several good reasons to assume that single embryo transfer (SET) eventually will become the norm internationally in IVF treatments. A tendency is clearly visible, as demonstrated in the latest IVF World Report. The Nordic countries and Belgium have been leading the way. Sweden at present has 70% SET, with 5% twins and a pregnancy rate per transfer remaining constant at about 30%. As a consequence, recent data show a drastic reduction of the risk of prematurity and therefore of child morbidity and perinatal mortality. It is now time to discuss alternatives to the current clinical policy of quite an aggressive ovarian stimulation in settings where SET is the norm. When and at what proportion could natural cycle/soft stimulation be used? What group of patients would benefit? What will the consequences be in terms of efficacy, safety, cost, time and quality of life? Selection of the most beneficial, rather than the most aggressive, ovarian stimulation protocol by clinicians and by the couples themselves in the future may well include a much wider use of natural cycle/soft stimulation in IVF. PMID:17509206

Nygren, Karl-Gösta

2007-05-01

149

5. Only a single coil is in the ground 6. Heat transfer up to the coil wall is axially symmetrical. /  

E-print Network

#12;SURFACE - 5. Only a single coil is in the ground 6. Heat transfer up to the coil wall be Figure 1. Diagram of ground coil. derived for the system shown in Figure i. Heat exchange between,). (2) O 9 2 r ar a, at Tf= Tfi(x) Heat transfer in the soil: T = Tp,(x, r) 2 T,~ I aT, I ~2 Ts,~I OT 3

Oak Ridge National Laboratory

150

Ultrafast single-electron transfer in coupled quantum dots driven by a few-cycle chirped pulse  

SciTech Connect

We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrödinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation.

Yang, Wen-Xing, E-mail: wenxingyang2@126.com [Department of Physics, Southeast University, Nanjing 210096 (China); Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Chen, Ai-Xi [Department of Applied Physics, School of Basic Science, East China Jiaotong University, Nanchang 330013 (China); Bai, Yanfeng [Department of Physics, Southeast University, Nanjing 210096 (China); Lee, Ray-Kuang [Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

2014-04-14

151

Complete replacement of the mitochondrial genotype in a Bos indicus calf reconstructed by nuclear transfer to a Bos taurus oocyte.  

PubMed Central

Due to the exclusively maternal inheritance of mitochondria, mitochondrial genotypes can be coupled to a particular nuclear genotype by continuous mating of founder females and their female offspring to males of the desired nuclear genotype. However, backcrossing is a gradual procedure that, apart from being lengthy, cannot ascertain that genetic and epigenetic changes will modify the original nuclear genotype. Animal cloning by nuclear transfer using host ooplasm carrying polymorphic mitochondrial genomes allows, among other biotechnology applications, the coupling of nuclear and mitochondrial genotypes of diverse origin within a single generation. Previous attempts to use Bos taurus oocytes as hosts to transfer nuclei from unrelated species led to the development to the blastocyst stage but none supported gestation to term. Our aim in this study was to determine whether B. taurus oocytes support development of nuclei from the closely related B. indicus cattle and to examine the fate of their mitochondrial genotypes throughout development. We show that indicus:taurus reconstructed oocytes develop to the blastocyst stage and produce live offspring after transfer to surrogate cows. We also demonstrate that, in reconstructed embryos, donor cell-derived mitochondria undergo a stringent genetic drift during early development leading, in most cases, to a reduction or complete elimination of B. indicus mtDNA. These results demonstrate that cross-subspecies animal cloning is a viable approach both for matching diverse nuclear and cytoplasmic genes to create novel breeds of cattle and for rescuing closely related endangered cattle. PMID:11333243

Meirelles, F V; Bordignon, V; Watanabe, Y; Watanabe, M; Dayan, A; Lôbo, R B; Garcia, J M; Smith, L C

2001-01-01

152

Connecting Rare DNA Conformations and Surface Dynamics using Single-Molecule Resonance Energy Transfer  

PubMed Central

A mechanistic understanding of single-stranded DNA (ssDNA) behavior in the near-surface environment is critical to advancing DNA-directed self-assembled nanomaterials. A new approach is described that uses total internal reflection fluorescence microscopy to measure resonance energy transfer at the single-molecule level, providing a mechanistic understanding of the connection between molecular conformation and interfacial dynamics near amine-modified surfaces. Large numbers (>105) of ssDNA trajectories were observed, permitting dynamic correlation of molecular conformation with desorption and surface mobility. On the basis of dynamic behavior, molecules could be designated as members of the more common coiled population or a rare, weakly bound conformation. Molecules in the coiled state generally exhibited slow diffusion and conformational fluctuations that decreased with increasing average end-to-end distance. Lattice simulations of adsorbed self-avoiding polymers successfully predicted these trends. In contrast, the weakly bound conformation, observed in about 5% of molecules, had a large end-to-end distance but demonstrated conformational fluctuations that were much higher than predicted by simulations for adsorbed flexible chains. This conformation correlated positively with desorption events and led to fast diffusion, indicating weak surface associations. Understanding the role of the weakly bound conformation in DNA hybridization, and how solution conditions and surface properties may favor it, could lead to improved self-assembled nanomaterials. PMID:21942411

Kastantin, Mark; Schwartz, Daniel K.

2011-01-01

153

The application of single photon detector technique in laser time transfer for Chinese navigation satellites  

NASA Astrophysics Data System (ADS)

The first Chinese mission of Laser Time Transfer (LTT) between ground and Chinese Navigation Satellites was successfully implemented by Shanghai Astronomical Observatory of Chinese Academy of Sciences. Because of LTT payloads onboard the High Earth Orbiting (HEO) satellites with orbit altitude of 21,500 to 36,000 km, the photon counting technology was adopted to increase the success rate of laser signal detection on satellites. The detection chip operates in a Geiger Mode with single photon sensitivity. It has a diameter of 40 um, it is produced by Czech Technical University. In order to reduce the background noise in space, the gated mode and two separated channels with different Field Of View (FOV) were used for the detector. The improvements for the next version of the LTT detector resulted in a lower background noise and better laser detection rate. It is also been demonstrated in the onboard experiments that the photon counting detector works well after sunlight directly entered into its optical window. Finally the LTT experiments result on Chinese Navigation Satellites are present in this paper. The clock and relative frequency difference were obtained with the single shot measuring resolution of about 300ps and 30 ps precision.

Meng, Wendong; Zhang, Haifeng; Zhang, Zhongping; Prochazka, Ivan

2013-05-01

154

Complete transfer of populations from a single state to a preselected superposition of states using piecewise adiabatic passage: Experiment  

SciTech Connect

We demonstrate a method of adiabatic population transfer from a single quantum state into a coherent superposition of states. The transfer is executed with femtosecond pulses, spectrally shaped in a simple and intuitive manner, which does not require iterative feedback-controlled loops. In contrast to nonadiabatic methods of excitation, our approach is not sensitive to the exact value of laser intensity. We show that the population transfer is complete, and analyze the possibility of controlling the relative phases and amplitudes of the excited eigenstates. We discuss the limitations of the proposed control methods due to the dynamic level shifts and suggest ways of reducing their influence.

Zhdanovich, S. [Departments of Physics and Astronomy, University of British Columbia, Vancouver (Canada); Laboratory for Advanced Spectroscopy and Imaging Research (LASIR), University of British Columbia, Vancouver (Canada); Shapiro, E. A. [Department of Chemistry, University of British Columbia, Vancouver (Canada); Hepburn, J. W.; Shapiro, M.; Milner, V. [Departments of Physics and Astronomy, University of British Columbia, Vancouver (Canada); Department of Chemistry, University of British Columbia, Vancouver (Canada); Laboratory for Advanced Spectroscopy and Imaging Research (LASIR), University of British Columbia, Vancouver (Canada)

2009-12-15

155

Repeated growth and bubbling transfer of graphene with millimetre-size single-crystal grains using platinum  

PubMed Central

Large single-crystal graphene is highly desired and important for the applications of graphene in electronics, as grain boundaries between graphene grains markedly degrade its quality and properties. Here we report the growth of millimetre-sized hexagonal single-crystal graphene and graphene films joined from such grains on Pt by ambient-pressure chemical vapour deposition. We report a bubbling method to transfer these single graphene grains and graphene films to arbitrary substrate, which is nondestructive not only to graphene, but also to the Pt substrates. The Pt substrates can be repeatedly used for graphene growth. The graphene shows high crystal quality with the reported lowest wrinkle height of 0.8 nm and a carrier mobility of greater than 7,100 cm2 V?1 s?1 under ambient conditions. The repeatable growth of graphene with large single-crystal grains on Pt and its nondestructive transfer may enable various applications. PMID:22426220

Gao, Libo; Ren, Wencai; Xu, Huilong; Jin, Li; Wang, Zhenxing; Ma, Teng; Ma, Lai-Peng; Zhang, Zhiyong; Fu, Qiang; Peng, Lian-Mao; Bao, Xinhe; Cheng, Hui-Ming

2012-01-01

156

NUMERICAL STUDY OF HEAT TRANSFER OF A SINGLE U-TUBE IN VERTICAL GROUND-COUPLED HEAT PUMP SYSTEMS  

Microsoft Academic Search

The heat transfer rate of a single U-tube ground heat exchanger was studied numerically. First, a 3D 60-m full scale computational model of a working single U-tube ground heat exchanger was built and numerical simulation was performed. The simulation was validated by comparing numerically calculated results with experimental results. After that, two models are built to compute the heat extraction

C F Ma; Y T Wu

157

Aerosol single scattering albedo retrieved from measurements of surface UV irradiance and a radiative transfer model  

NASA Astrophysics Data System (ADS)

Aerosol single scattering albedo (?), the ratio of aerosol scattering coefficient to total aerosol extinction coefficient, at UV wavelengths is an important aerosol radiative parameter in determining surface UV irradiance. Surface measurements of total and diffuse UV irradiance in the summer and fall of 1999 at the seven narrowband wavelength channels of an UV multifilter rotating shadowband radiometer (UVMFR-SR) at Black Mountain, N. C., were coupled with a tropospheric ultraviolet radiative transfer model to produce values of ?. Its value ranged from 0.65 to 0.91 at 300 nm, 0.71 to 0.96 at 305.5 nm, 0.73 to 0.97 at 311.4 nm, 0.74 to 0.91 at 317.6 nm, 0.76 to 0.96 at 325.4 nm, 0.77 to 0.97 at 332.4 nm, and 0.80 to 0.99 at 368 nm. Error in this procedure decreases with increasing aerosol optical depth (AOD), from ±0.63 at AOD = 0.05 to ±0.04 at AOD = 1.0 averaged over the seven wavelengths. The current values of ? have a slightly wider variation than values reported from a previous study at the same site. The lower values of ? could indicate that, over the site, preferential absorption of UV radiation by black carbon aerosols could be occurring. More values of ? in the UV spectrum will allow for better estimation of this parameter for UV radiative transfer modeling and will lessen error in estimation of surface UV irradiances.

Petters, J. L.; Saxena, V. K.; Slusser, J. R.; Wenny, B. N.; Madronich, Sasha

2003-05-01

158

Electron Transport, Energy Transfer, and Optical Response in Single Molecule Junctions  

NASA Astrophysics Data System (ADS)

The last decade has seen incredible growth in the quality of experiments being done on single molecule junctions. Contemporary experimental measurements have expanded far beyond simple electron transport. Measurement of vibronic eects, quantum interference and decoherence eects, molecular optical response (Raman spectroscopy), and molecular spintronics are just some of the continuing areas of research in single molecule junctions. Experimental advancements demand advanced theoretical treatments, which can be used accurately within appropriate physical regimes, in order to understand measured phenomena and predict interesting directions for future study. In this dissertation we will study systems with strong intra-system interactions using a many-body states based approach. We will be focused on three related processes in molecular junctions: electron transport, electronic energy transfer, and molecular excitation. Inelastic electron transport in the regime of strong and nonlinear electron-vibration coupling within and outside of the Born-Oppenheimer regime will be investigated. To understand their appropriateness, we will compare simple semi-classical approximations in molecular redox junctions and electron-counting devices to fully quantum calculations based on many-body system states. The role of coherence and quantum interference in energy and electron transfer in molecular junctions is explored. Experiments that simultaneously measure surface enhanced Raman scattering and electron conduction have revealed a strong interaction between conducting electrons and molecular excitation. We investigate the role of the molecular response to a classical surface plasmon enhanced electric eld considering the back action of the oscillating molecular dipole. Raman scattering is quantum mechanical by nature and involves strong interaction between surface plasmons in the contacts and the molecular excitation. We develop a scheme for treating strong plasmon-molecular excitation interactions quantum mechanically within nonequilibrium molecular junctions. Finally we perform preliminary calculations of the Raman spectrum of a three-ring oligophenylene vinylene terminating in amine functional groups molecule in a molecular junction and compare our results to experimental measurements. This work is the rst steps towards full calculations of the optical response of current-carrying molecular junction, which should combine classical calculations of the plasmon enhanced electric field with quantum calculations for the plasmon-molecular exciton interaction and nonequilibrium Raman scattering.

White, Alexander James

159

Effects of lead on the male mouse as investigated by in vitro fertilization and blastocyst culture  

SciTech Connect

Long-term exposure of male mice to inorganic lead (lead chloride, 1 g/liter) in the drinking water reduces their fertility. The cause of this reduction, expressed as a decrease in the number of mated females showing inplantations, was investigated, using an in vivo fertilization method. It was found that spermatozoa from lead-exposed males had a significantly lower ability to fertilize mouse eggs than those from unexposed males. Preimplantation embryos, isolated from uterine horns of mice mated with lead-exposed males. Preimplantation embryos, isolated from uterine horns of mice mated with lead-exposed males, were examined. No morphologically abnormal embryos were found. However, when cultured in vitro over the implantation period, blastocysts of the group mated with lead-exposed males showed an increased frequency of delayed hatching from the zona pellucida or an inability to hatch. Among blastocysts from this group a decreased frequency of inner cell mass development was also found.

Johansson, L.; Sjoeblom, P.; Wide, M.

1987-02-01

160

HIPPO Pathway Members Restrict SOX2 to the Inner Cell Mass Where It Promotes ICM Fates in the Mouse Blastocyst  

PubMed Central

Pluripotent epiblast (EPI) cells, present in the inner cell mass (ICM) of the mouse blastocyst, are progenitors of both embryonic stem (ES) cells and the fetus. Discovering how pluripotency genes regulate cell fate decisions in the blastocyst provides a valuable way to understand how pluripotency is normally established. EPI cells are specified by two consecutive cell fate decisions. The first decision segregates ICM from trophectoderm (TE), an extraembryonic cell type. The second decision subdivides ICM into EPI and primitive endoderm (PE), another extraembryonic cell type. Here, we investigate the roles and regulation of the pluripotency gene Sox2 during blastocyst formation. First, we investigate the regulation of Sox2 patterning and show that SOX2 is restricted to ICM progenitors prior to blastocyst formation by members of the HIPPO pathway, independent of CDX2, the TE transcription factor that restricts Oct4 and Nanog to the ICM. Second, we investigate the requirement for Sox2 in cell fate specification during blastocyst formation. We show that neither maternal (M) nor zygotic (Z) Sox2 is required for blastocyst formation, nor for initial expression of the pluripotency genes Oct4 or Nanog in the ICM. Rather, Z Sox2 initially promotes development of the primitive endoderm (PE) non cell-autonomously via FGF4, and then later maintains expression of pluripotency genes in the ICM. The significance of these observations is that 1) ICM and TE genes are spatially patterned in parallel prior to blastocyst formation and 2) both the roles and regulation of Sox2 in the blastocyst are unique compared to other pluripotency factors such as Oct4 or Nanog. PMID:25340657

Frum, Tristan; Hirate, Yoshikazu; Lang, Richard A.; Sasaki, Hiroshi; Ralston, Amy

2014-01-01

161

Unsteady conjugate heat transfer for a single particle and in multi-particle systems at low Reynolds numbers  

Microsoft Academic Search

Two cases of the transient conjugate heat transfer in fluid-particle systems are analysed. The first refers to the single rigid spherical particle at particle Reynolds numbers greater than one. The subject of the second is the assemblages of rigid spherical particles at low particle Reynolds numbers, i.e. Re ? 20. In this case the classical cell models are used to

G. H. Juncu

1998-01-01

162

Influence of temperature on mass transfer in an incomplete trapping single hollow fibre supported liquid membrane extraction of triazole fungicides  

Microsoft Academic Search

The influence of temperature in a single hollow fibre supported liquid membrane extraction of triazole fungicides with a stagnant acceptor phase was investigated. The mass transfer parameters such as diffusion coefficient, flux and apparent viscosity were determined at temperature ranging from 278K to 313K. Increase in temperature led to an increase in diffusion coefficient and flux. The apparent viscosity also

Monika Michel; Luke Chimuka; Ewa Cukrowska; Piotr Wieczorek; Bogus?aw Buszewski

2009-01-01

163

Single-scattering properties of tri-axial ellipsoidal mineral dust aerosols: A database for application to radiative transfer calculations  

E-print Network

Single-scattering properties of tri-axial ellipsoidal mineral dust aerosols: A database Optical properties Database a b s t r a c t This paper presents a user-friendly database software package transfer calculations in a spectral region from ultraviolet (UV) to far-infrared (far-IR). To expand

Liou, K. N.

164

Evidence of electron-transfer in the SERS spectra of a single iron-protoporphyrin IX molecule  

E-print Network

Evidence of electron-transfer in the SERS spectra of a single iron-protoporphyrin IX molecule Anna molecule iron-protoporphyrin IX, adsorbed on silver colloidal surfaces. If on one hand, drastic, random molecule detection [5,6]. A drastic increase, up to 1014 , of the Raman cross section can be achieved

Tuscia, Università Degli Studi Della

165

Dimensional feature weighting utilizing multiple kernel learning for single-channel talker location discrimination using the acoustic transfer function.  

PubMed

This paper presents a method for discriminating the location of the sound source (talker) using only a single microphone. In a previous work, the single-channel approach for discriminating the location of the sound source was discussed, where the acoustic transfer function from a user's position is estimated by using a hidden Markov model of clean speech in the cepstral domain. In this paper, each cepstral dimension of the acoustic transfer function is newly weighted, in order to obtain the cepstral dimensions having information that is useful for classifying the user's position. Then, this paper proposes a feature-weighting method for the cepstral parameter using multiple kernel learning, defining the base kernels for each cepstral dimension of the acoustic transfer function. The user's position is trained and classified by support vector machine. The effectiveness of this method has been confirmed by sound source (talker) localization experiments performed in different room environments. PMID:23363107

Takashima, Ryoichi; Takiguchi, Tetsuya; Ariki, Yasuo

2013-02-01

166

Targeted organ generation using mixl1-inducible mouse pluripotent stem cells in blastocyst complementation.  

PubMed

Generation of functional organs from patients' own cells is one of the ultimate goals of regenerative medicine. As a novel approach to creation of organs from pluripotent stem cells (PSCs), we employed blastocyst complementation in organogenesis-disabled animals and successfully generated PSC-derived pancreas and kidneys. Blastocyst complementation, which exploits the capacity of PSCs to participate in forming chimeras, does not, however, exclude contribution of PSCs to the development of tissues-including neural cells or germ cells-other than those specifically targeted by disabling of organogenesis. This fact provokes ethical controversy if human PSCs are to be used. In this study, we demonstrated that forced expression of Mix-like protein 1 (encoded by Mixl1) can be used to guide contribution of mouse embryonic stem cells to endodermal organs after blastocyst injection. We then succeeded in applying this method to generate functional pancreas in pancreatogenesis-disabled Pdx1 knockout mice using a newly developed tetraploid-based organ-complementation method. These findings hold promise for targeted organ generation from patients' own PSCs in livestock animals. PMID:25192056

Kobayashi, Toshihiro; Kato-Itoh, Megumi; Nakauchi, Hiromitsu

2015-01-15

167

Introduction of blastocyst culture and transfer for all patients in an in vitro fertilization program  

Microsoft Academic Search

Objective: To evaluate the nonselective application of extended embryo culture on the outcome of IVF.Design: Retrospective analysis.Setting: Private practice assisted reproductive technology center.Patient(s): Seven hundred ninety nonselected patients undergoing IVF with controlled ovarian stimulation.Intervention(s): For day 3 ET, multicell embryos were cultured in human tubal fluid medium and 12% synthetic serum substitute. For day 5 ET, embryos were cultured for

Del Marek; Martin Langley; David K Gardner; Nils Confer; Kathleen M Doody; Kevin J Doody

1999-01-01

168

The use of the Brinkman number for single phase forced convective heat transfer in microchannels  

Microsoft Academic Search

From a survey on studies on convective heat transfer in microchannels, the Brinkman number is proposed as a parameter for correlating the convective heat transfer parameters in microchannels. The proposal emerges from a dimensional analysis of the variables influencing the laminar forced convection in microchannels and it can explain the unusual behaviour of convective heat transfer in the laminar regime

C. P. Tso; S. P. Mahulikar

1998-01-01

169

Collapse of a long axis: single-molecule Förster resonance energy transfer and serpin equilibrium unfolding.  

PubMed

The energy required for mechanical inhibition of target proteases is stored in the native structure of inhibitory serpins and accessed by serpin structural remodeling. The overall serpin fold is ellipsoidal with one long and two short axes. Most of the structural remodeling required for function occurs along the long axis, while expansion of the short axes is associated with misfolded, inactive forms. This suggests that ellipticity, as typified by the long axis, may be important for both function and folding. Placement of donor and acceptor fluorophores approximately along the long axis or one of the short axes allows single-pair Förster resonance energy transfer (spFRET) to report on both unfolding transitions and the time-averaged shape of different conformations. Equilibrium unfolding and refolding studies of the well-characterized inhibitory serpin ?1-antitrypsin reveal that the long axis collapses in the folding intermediates while the monitored short axis expands. These energetically distinct intermediates are thus more spherical than the native state. Our spFRET studies agree with other equilibrium unfolding studies that found that the region around one of the ? strands, s5A, which helps define the long axis and must move for functionally required loop insertion, unfolds at low denaturant concentrations. This supports a connection between functionally important structural lability and unfolding in the inhibitory serpins. PMID:24749911

Liu, Lu; Werner, Michael; Gershenson, Anne

2014-05-13

170

Current Status of Comprehensive Chromosome Screening for Elective Single-Embryo Transfer  

PubMed Central

Most in vitro fertilization (IVF) experts and infertility patients agree that the most ideal assisted reproductive technology (ART) outcome is to have a healthy, full-term singleton born. To this end, the most reliable policy is the single-embryo transfer (SET). However, unsatisfactory results in IVF may result from plenty of factors, in which aneuploidy associated with advanced maternal age is a major hurdle. Throughout the past few years, we have got a big leap in advancement of the genetic screening of embryos on aneuploidy, translocation, or mutations. This facilitates a higher success rate in IVF accompanied by the policy of elective SET (eSET). As the cost is lowering while the scale of genome characterization continues to be up over the recent years, the contemporary technologies on trophectoderm biopsy and freezing-thaw, comprehensive chromosome screening (CCS) with eSET appear to be getting more and more popular for modern IVF centers. Furthermore, evidence has showen that, by these avant-garde techniques (trophectoderm biopsy, vitrification, and CCS), older infertile women with the help of eSET may have an opportunity to increase the success of their live birth rates approaching those reported in younger infertility patients. PMID:24991216

Wu, Ming-Yih; Chao, Kuang-Han; Chen, Chin-Der; Chang, Li-Jung; Chen, Shee-Uan; Yang, Yu-Shih

2014-01-01

171

Single-crystal organic charge-transfer interfaces probed using Schottky-gated heterostructures  

NASA Astrophysics Data System (ADS)

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the heterointerfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN2 single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behaviour from room temperature to ~150?K, and remains as high as ~1?cm2?V-1?s-1 at 30?K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively on the basis of the heterostructure band diagram. These results elucidate the electronic structure of rubrene/PDIF-CN2 interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.

Lezama, Ignacio Gutiérrez; Nakano, Masaki; Minder, Nikolas A.; Chen, Zhihua; di Girolamo, Flavia V.; Facchetti, Antonio; Morpurgo, Alberto F.

2012-09-01

172

81 jak-stat signalling is critical for inner cell mass development in bovine blastocysts.  

PubMed

The inner cell mass (ICM) of mammalian blastocysts comprises 2 transient lineages, namely hypoblast and epiblast, which develop into extra-embryonic and embryonic tissues, respectively. In the mouse, epiblast cells autocrinally secrete fibroblast growth factor (FGF) to induce hypoblast differentiation, and pharmacological FGF/mitogen-activated protein kinase (MAPK) signal inhibition converts all ICM cells into epiblast. We conducted a chemical screen for additional signal enhancers of epiblast identity in bovine Day 8 blastocysts. From the morula stage onwards, in vitro-fertilised (IVF) embryos were cultured in the presence of 9 small molecule inhibitors, targeting 9 principal signal pathway components. Inhibitors included SB431542, LDN193189, BIBF1120, Forskolin, BI-D1870, A66/TGX 221/ZSTK474, and AZD1480, targeting TGF?-RI, BMP-RI, VEGFR/PDGFR/FGFR, adenylate cyclase, ribosomal S6 kinase (RSK), PI3K, and JAK2 signalling, respectively. Using (1) blastocyst quality (by morphological grading), (2) cell numbers (by differential stain), and (3) lineage-specific candidate gene expression (by quantitative PCR) as readouts, we sought to identify positive and negative regulators of ICM development and lineage determination. Based on our previous digital mRNA profiling data (McLean et al. 2014 Biol. Reprod., in press), we selected discriminatory epiblast-specific (FGF4, NANOG) and hypoblast-specific (PDGFR?, SOX17) markers for qPCR analysis. Each inhibitor was compared, alone or in combination, to an appropriately diluted dimethylsulfoxide (DMSO) vehicle control in at least 3 biological replicates. Statistical significance was determined using a generalised linear mixed model with binomial distribution and logit link for developmental data and REML for log cell counts and log gene expression data, applying fixed treatment effects and random run and sample within run effects. Blocking TGF?1-, BMP- or VEGF-/PDGF-/FGF-signalling did not affect blastocyst development, ICM v. trophectoderm (TE) cell numbers, or gene expression. Repression of PI3K signals via AG66 and TGX, but not ZSTK alone, modestly decreased grade 1-2 blastocyst development (P<0.05) but had no effect on cell numbers or gene expression. Stimulating adenylate cyclase activity increased NANOG levels (2.5-fold; P<0.05), while RSK inhibition reduced FGF4 and PDGFR? expression (4-fold and 2-fold, respectively; P<0.05). Suppressing JAK-STAT signalling, on the other hand, consistently compromised grade 1-2 blastocyst development and ICM numbers relative to DMSO controls (18/235=7% v. 59/159=29%, n=5 IVF runs; 12 v. 47 ICM cells, N=25 and N=7 embryos counted, respectively; P<0.0001). Epiblast and hypoblast markers were up to 40-fold reduced (FGF4, NANOG, SOX17; P<0.0001) or completely abolished (PDGFR?; P<0.0001). This effect was specific to the ICM because TE numbers and TE-specific gene expression (CDX2, KTR8) were not significantly altered. In summary, we have established Day 8 blastocysts as a useful chemical screening platform and demonstrated that bovine ICM development critically depends on JAK-STAT signalling. PMID:25472130

Meng, F; Forrester-Gauntlett, B; Henderson, H; Oback, B

2014-12-01

173

Single collision gas-surface vibrational energy transfer in reactive systems. Variation of initial energy distribution  

SciTech Connect

The initial vibrational energy distribution of molecules that collide with a hot surface has been varied. The effect of the variation on the collisional reaction probability (P/sub c/) has been studied under single collision conditions. These experiments provide a more sensitive test of the relative suitability of various analytical forms for the collisional transition probability matrix P than has been achieved previously in earlier VEM experiments. The reaction system is the isomerization of cyclobutene to 1, 3-butadiene. A seasoned fused quartz surface was used over the temperature range T/sub r/ = 600--900 K. Variation of the initial vibrational energy population vector of cyclobutene molecules was made by change of their initial temperature T/sub c/ in the range 273--620 K. The experimental collisional efficiency ..beta../sub 1/ declined from 0.31 to 0.013 over the combination temperature ranges T/sub r/, T/sub c/ = 600,500 to 900,273. Stochastic models of the vibrational transition probability were fitted to the data and provided values for the average amount of energy (<..delta..E'>/sub E//sub 0/) transferred from the hot molecules in a down transition from the threshold energy level E/sub 0/; Gaussian or Boltzmann exponential forms of P prove to be the most suitable to fit the data. Calculated values, <..delta..E'>/sub E//sub 0/ on the basis of a Gaussian function model for P declined from 5600 to 3700 cm/sup -1/ with increase in the surface temperature from 600 to 900 K.

Arakawa, R.; Kelley, D.F.; Rabinovitch, B.S.

1982-03-01

174

The Effect of Single Embryo Transfer on Perinatal Outcomes in Japan  

PubMed Central

Objective: In 2007 and 2008, the Japan Society for Reproductive Medicine and the Japan Society of Obstetrics and Gynecology issued a recommendation for single embryo transfer (SET). Thereafter, SET was implemented in 73% of in vitro fertilization (IVF) cases in Japan. The purpose of this study was to evaluate the effects of compliance with the SET recommendation on perinatal outcomes. Methods: An electronic audit of the perinatal database of the Japanese Society of Obstetrics and Gynecology was conducted from 2001 through 2010. The database comprised data of 610,726 women. Totally, 20,923 women conceived through IVF. To compare perinatal outcomes, these women were categorized into two study groups depending on whether they conceived before (2004-2005, n = 3,865) or after (2009-2010, n = 6,842) the SET recommendation statement was issued. Results: The proportion of women who conceived through IVF increased from 1.3% in 2001 to 4.8% in 2010. Compliance with the SET recommendation led to a decrease in the incidence of twin pregnancies (33.9% versus 13%, p < 0.01), incidence of preterm delivery (odds ratio [OR]: 0.54, 95% confidence interval [CI]: 0.50-0.59), low birth weight (OR: 0.42, 95% CI: 0.39-0.45), and neonatal intensive care unit admission (OR 0.70, 95% CI 0.65-0.76), but an increase in the incidence of monochorionic twins (1.6% versus 2.5%, p < 0.01). Conclusion: Compliance with the SET recommendation improved perinatal outcomes by reducing the incidence of twin pregnancies. PMID:25552919

Hayashi, Masako; Satoh, Shoji; Matsuda, Yoshio; Nakai, Akihito

2015-01-01

175

Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction.  

PubMed

Much recent progress has been made by assisted reproductive technology (ART) professionals toward minimizing the incidence of multiple pregnancy following ART treatment. While a healthy singleton birth is widely considered to be the ideal outcome of such treatment, a vocal minority continues a campaign to advocate the benefits of multiple embryo transfer as treatment and twin pregnancy as outcome for most ART patients. Proponents of twinning argue four points: that patients prefer twins, that multiple embryo transfer maximizes success rates, that the costs per infant are lower with twins and that one twin pregnancy and birth is associated with no higher risk than two consecutive singleton pregnancies and births. We find fault with the reasoning and data behind each of these tenets. First, we respect the principle of patient autonomy to choose the number of embryos for transfer but counter that it has been shown that better patient education reduces their desire for twins. In addition, reasonable and evidentially supported limits may be placed on autonomy in exchange for public or private insurance coverage for ART treatment, and counterbalancing ethical principles to autonomy exist, especially beneficence (doing good) and non-maleficence (doing no harm). Second, comparisons between success rates following single-embryo transfer (SET) and double-embryo transfers favor double-embryo transfers only when embryo utilization is not comparable; cumulative pregnancy and birth rates that take into account utilization of cryopreserved embryos (and the additional cryopreserved embryo available with single fresh embryo transfer) consistently demonstrate no advantage to double-embryo transfer. Third, while comparisons of costs are system dependent and not easy to assess, several independent studies all suggest that short-term costs per child (through the neonatal period alone) are lower with transfers of one rather than two embryos. And, finally, abundant evidence conclusively demonstrates that the risks to both mother and especially to children are substantially greater with one twin birth compared with two singleton births. Thus, the arguments used by some to promote multiple embryo transfer and twinning are not supported by the facts. They should not detract from efforts to further promote SET and thus reduce ART-associated multiple pregnancy and its inherent risks. PMID:23904468

Stillman, Robert J; Richter, Kevin S; Jones, Howard W

2013-10-01

176

Single-particle studies of band alignment effects on electron transfer dynamics from semiconductor hetero-nanostructures to single-walled carbon nanotubes.  

PubMed

We utilize single-molecule spectroscopy combined with time-correlated single-photon counting to probe the electron transfer (ET) rates from various types of semiconductor hetero-nanocrystals, having either type-I or type-II band alignment, to single-walled carbon nanotubes. A significantly larger ET rate was observed for type-II ZnSe/CdS dot-in-rod nanostructures as compared to type-I spherical CdSe/ZnS core/shell quantum dots and to CdSe/CdS dot-in-rod structures. Furthermore, such rapid ET dynamics can compete with both Auger and radiative recombination processes, with significance for effective photovoltaic operation. PMID:22136306

Yuan, Chi-Tsu; Wang, Yong-Gang; Huang, Kuo-Yen; Chen, Ting-Yu; Yu, Pyng; Tang, Jau; Sitt, Amit; Banin, Uri; Millo, Oded

2012-01-24

177

Vortex pattern of the turbulent flow around a single cube on a flat surface and its heat transfer at different attack angles  

Microsoft Academic Search

Experimental results on convective heat transfer from a single cube on a flat surface are presented for different attack angles\\u000a to the incident flow and Reynolds numbers. The character of vortex formation and the effect of flow structure on heat transfer\\u000a at detached flow around a cube were studied by visualization. Local heat transfer and heat transfer averaged over the

V. I. Terekhov; A. I. Gnyrya; S. V. Korobkov

2010-01-01

178

Validity ranges of three analytical solutions to heat transfer in the vicinity of single boreholes  

Microsoft Academic Search

In ground-coupled heat pump systems, accurate prediction of transient ground heat transfer is important to establish the required borehole length and to determine precisely the resulting fluid temperature. Three analytical solutions to transient heat transfer in the vicinity of geothermal boreholes are presented. These solutions are referred to as the infinite line source (ILS), the infinite cylindrical source (ICS) and

Mikael Philippe; Michel Bernier; Dominique Marchio

2009-01-01

179

Friction and metal transfer for single-crystal silicon carbide in contact with various metals in vacuum  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with single-crystal silicon carbide in contact with transition metals (tungsten, iron, rhodium, nickel, titanium, and cobalt), copper, and aluminum. Results indicate the coefficient of friction for a silicon carbide-metal system is related to the d bond character and relative chemical activity of the metal. The more active the metal, the higher the coefficient of friction. All the metals examined transferred to the surface of silicon carbide in sliding. The chemical activity of metal to silicon and carbon and shear modulus of the metal may play important roles in metal transfer and the form of the wear debris. The less active and greater resistance to shear the metal has, with the exception of rhodium and tungsten, the less transfer to silicon carbide.

Miyoshi, K.; Buckley, D. H.

1978-01-01

180

Cross sections for single electron capture, transfer ionization and direct ioniza-tion in Li3+- Ne collisions  

NASA Astrophysics Data System (ADS)

Multiple ionization cross sections of Ne atoms are reported for Li3+ impact in the energy range of 2 to 5.8MeV. The neon ionization cross sections were separated into three collision channels, namely; direct ionization (DI), single capture (SC) and transfer ionization (TI). The direct ionization data is compared to CDW-EIS calculations as well as to other projectiles with charge state q = 3+. The single capture is compared to a modified Bohr-Lindhard semi classical model.

Luna, H.; Junger, I.; Pinto Cordeiro, A. C.; Wolff, W.; Montenegro, E. C.; Montanari, C. C.; Miraglia, J. E.

2012-11-01

181

Experimental and numerical study of pressure drop and heat transfer in a single-phase micro-channel heat sink  

Microsoft Academic Search

The pressure drop and heat transfer characteristics of a single-phase micro-channel heat sink were investigated both experimentally and numerically. The heat sink was fabricated from oxygen-free copper and fitted with a polycarbonate plastic cover plate. The heat sink consisted of an array of rectangular micro-channels 231?m wide and 713?m deep. Deionized water was employed as the cooling liquid and two

Weilin Qu; Issam Mudawar

2002-01-01

182

Influence of heat and mass transfer on the ignition and NO x formation in single droplet combustion  

Microsoft Academic Search

The effect of heat and mass transfer on the ignition, and in a second step on the nitrogen oxide (NO\\u000a x\\u000a ) generation, of single burning droplets is examined in a numerical study. Spherical symmetry with no gravity and no forced\\u000a convection is presumed; ambient temperature is set at 500 K, below the auto-ignition point. The essentials of a forced

Klaus G. MoeslJoachim; Joachim E. Schwing; Wolfgang J. Fenninger; Thomas Sattelmayer

183

78 noninvasive cell lineage tracing in bovine embryos from 2-cell stage up to blastocyst stage.  

PubMed

The first lineage specification occurs during pre-implantation mammalian development. At the blastocyst stage, 2 cell lineages can be distinguished: the inner cell mass (ICM) and the trophectoderm (TE). The exact timing when embryo cells are skewed to these lineages is not clearly determined in mammalian species. In murine embryos, it has been suggested that the first cleavage plane might be related to the embryonic-abembryonic (Em-Ab) axis at blastocyst stage. Thus, the daughter cells of the 2-cell embryo might already be predisposed to a specific cell lineage further on development. The objective of the present study was to observe how the first cleavage in bovine embryos may be related to cell lineage allocation at the blastocyst stage, using a noninvasive tracing approach. Bovine oocytes were harvested, in vitro matured, and fertilised. At the 2-cell stage, embryos were injected in one blastomere with the membrane tracer DiI. At the blastocyst stage, embryos (n=346) were classified as orthogonal when the Em-Ab axis was orthogonally divided by the borderline between labelled and non-labelled cells; as deviant if the borderline was overlapping the Em-Ab axis; and as random when the labelled and non-labelled cells were randomly distributed. Total cell count (TCC) and the ICM/TE ratio was allowed by DNA staining with 4',6-diamidino-2-phenylindole (DAPI) and by immunostaining of the ICM with Sox2 antibody. Analysis of variance was performed by one-way ANOVA employing IBM SPSS v21 (SPSS Inc., Chicago, IL, USA) to determine any difference between the cell lineage allocation patterns, TCC, and the ICM/TE ratio. P-values=0.05 were considered significant. All values are reported as mean ± standard error of mean. Within 40 repetitions, the blastocyst classification was as follows: orthogonal 14.9% (±2.32, n=56), deviant 22.2% (±2.58, n=80), and random 62.9% (±2.64, n=210). A significant difference was found in the incidence between the random group against the orthogonal and deviant, but not between the latter two. Regarding TCC, a significant difference was observed only between the orthogonal (99.6±11.7 cells, n=15) and deviant (135±7.3 cells, n=25) groups, but not with random embryos (116±5.5 cells, n=42). Finally, no significant difference was found among the groups concerning the ICM/TE ratio (0.43±0.07 for orthogonal, n=7; 0.54±0.06 for deviant, n=14; and 0.40±0.03 for random embryos, n=26). In conclusion, bovine embryos present a marked tendency for a random distribution of the daughter cells derived from the 2-cell blastomeres. However, around 37% of the blastocysts present a patterned cell division, where the daughter cells remain together through pre-implantation development. The effect of these cell lineage allocation patterns on implantation and further embryo development needs to be addressed. PMID:25472127

Sepulveda-Rincon, L P; Dube, D; Adenot, P; Laffont, L; Ruffini, S; Gall, L; Maalouf, W E; Duranthon, V; Beaujean, N

2014-12-01

184

Effect of Hyaluronan on Developmental Competence and Quality of Oocytes and Obtained Blastocysts from In Vitro Maturation of Bovine Oocytes  

PubMed Central

The objective of the present study was to evaluate the effect of hyaluronan (HA) during IVM on meiotic maturation, embryonic development, and the quality of oocytes, granulosa cells (GC), and obtained blastocysts. COCs were matured in vitro in control medium and medium with additional 0.035% or 0.07% of exogenous HA. The meiotic maturity did not differ between the analysed groups. The best rate and the highest quality of obtained blastocysts were observed when 0.07% HA was used. A highly significant difference (P < 0.001) was noted in the mean number of apoptotic nuclei per blastocyst and in the DCI between the 0.07% HA and the control blastocysts (P < 0.01). Our results suggest that addition of 0.035% HA and 0.07% HA to oocyte maturation media does not affect oocyte nuclear maturation and DNA fragmentation. However, the addition of 0.07% HA during IVM decreases the level of blastocysts DNA fragmentation. Finally, our results suggest that it may be risky to increase the HA concentration during IVM above 0.07% as we found significantly higher Bax mRNA expression levels in GC cultured with 0.07% HA. The final concentration of HA being supplemented to oocyte maturation media is critical for the success of the IVP procedure. PMID:24689043

Opiela, Jolanta; Romanek, Joanna; Lipi?ski, Daniel; Smor?g, Zdzis?aw

2014-01-01

185

Comparison of Blastocyst and Sage Media for In Vitro Maturation of Human Immature Oocytes.  

PubMed

In vitro maturation (IVM) of human oocytes is an attractive alternative to conventional assisted reproductive technology (ART) treatment, as it involves no or minimal ovarian stimulation. Currently, commercialized media specifically designed for IVM are often used. These media are expensive, have limited shelf life, and must be ordered in advance. If standard culture media can be used in place of the specialized IVM media, it would simplify management and make IVM more feasible and more widely employed in ART centers around the world, especially in developing countries where resources are scarce. This study was, therefore, conducted to test the hypothesis that blastocyst medium was as good as commercial IVM medium to support maturation and developmental competence of human immature oocytes as previously shown in the mouse system. Immature oocytes were obtained by needle aspiration from 89 pregnant women during cesarean deliveries between April 2012 and February 2013. Sibling oocytes were allocated to Sage IVM media (512 oocytes) or blastocyst medium (520 oocytes) and assessed for maturation 36 hours later. Mature oocytes were inseminated by intracytoplasmic sperm injection and cultured up to 144 hours. There was no difference in maturation rate (65.0% vs 68.7%; P = .218) or fertilization rate (66.9% vs 66.4%; P = .872) of oocytes matured in vitro in both media. There was also no difference in the formation of good-quality blastocysts (46.6% vs 45.9%; P = .889) in the 2 groups. Further study should be done to ascertain implantation and pregnancy potential of these embryos. PMID:25015901

Pongsuthirak, Pallop; Songveeratham, Sorramon; Vutyavanich, Teraporn

2014-07-11

186

Effects of Trichostatin A on In vitro Development of Porcine Embryos Derived from Somatic Cell Nuclear Transfer  

PubMed Central

Many different approaches have been developed to improve the efficiency of animal cloning by somatic cell nuclear transfer (SCNT), one of which is to modify histone acetylation levels using histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA). In the present study, we examined the effect of TSA on in vitro development of porcine embryos derived from SCNT. We found that TSA treatment (50 nM) for 24 h following oocyte activation improved blastocyst formation rates (to 22.0%) compared with 8.9% in the non-treatment group and total cell number of the blastocysts for determining embryo quality also increased significantly (88.9?114.4). Changes in histone acetylation levels as a result of TSA treatment were examined using indirect immunofluorescence and confocal microscopy scanning. Results showed that the histone acetylation level in TSA-treated embryos was higher than that in controls at both acetylated histone H3 lysine 9 (AcH3K9) and acetylated histone H4 lysine 12 (AcH4K12). Next, we compared the expression patterns of seven genes (OCT4, ID1; the pluripotent genes, H19, NNAT, PEG1; the imprinting genes, cytokeratin 8 and 18; the trophoblast marker genes). The SCNT blastocysts both with and without TSA treatment showed lower levels of OCT4, ID1, cytokeratin 8 and 18 than those of the in vivo blastocysts. In the case of the imprinting genes H19 and NNAT, except PEG1, the SCNT blastocysts both with and without TSA treatment showed higher levels than those of the in vivo blastocysts. Although the gene expression patterns between cloned blastocysts and their in vivo counterparts were different regardless of TSA treatment, it appears that several genes in NT blastocysts after TSA treatment showed a slight tendency toward expression patterns of in vivo blastocysts. Our results suggest that TSA treatment may improve preimplantation porcine embryo development following SCNT. PMID:25049758

Jeong, Yeon Ik; Park, Chi Hun; Kim, Huen Suk; Jeong, Yeon Woo; Lee, Jong Yun; Park, Sun Woo; Lee, Se Yeong; Hyun, Sang Hwan; Kim, Yeun Wook; Shin, Taeyoung; Hwang, Woo Suk

2013-01-01

187

Effects of Trichostatin A on In vitro Development of Porcine Embryos Derived from Somatic Cell Nuclear Transfer.  

PubMed

Many different approaches have been developed to improve the efficiency of animal cloning by somatic cell nuclear transfer (SCNT), one of which is to modify histone acetylation levels using histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA). In the present study, we examined the effect of TSA on in vitro development of porcine embryos derived from SCNT. We found that TSA treatment (50 nM) for 24 h following oocyte activation improved blastocyst formation rates (to 22.0%) compared with 8.9% in the non-treatment group and total cell number of the blastocysts for determining embryo quality also increased significantly (88.9?114.4). Changes in histone acetylation levels as a result of TSA treatment were examined using indirect immunofluorescence and confocal microscopy scanning. Results showed that the histone acetylation level in TSA-treated embryos was higher than that in controls at both acetylated histone H3 lysine 9 (AcH3K9) and acetylated histone H4 lysine 12 (AcH4K12). Next, we compared the expression patterns of seven genes (OCT4, ID1; the pluripotent genes, H19, NNAT, PEG1; the imprinting genes, cytokeratin 8 and 18; the trophoblast marker genes). The SCNT blastocysts both with and without TSA treatment showed lower levels of OCT4, ID1, cytokeratin 8 and 18 than those of the in vivo blastocysts. In the case of the imprinting genes H19 and NNAT, except PEG1, the SCNT blastocysts both with and without TSA treatment showed higher levels than those of the in vivo blastocysts. Although the gene expression patterns between cloned blastocysts and their in vivo counterparts were different regardless of TSA treatment, it appears that several genes in NT blastocysts after TSA treatment showed a slight tendency toward expression patterns of in vivo blastocysts. Our results suggest that TSA treatment may improve preimplantation porcine embryo development following SCNT. PMID:25049758

Jeong, Yeon Ik; Park, Chi Hun; Kim, Huen Suk; Jeong, Yeon Woo; Lee, Jong Yun; Park, Sun Woo; Lee, Se Yeong; Hyun, Sang Hwan; Kim, Yeun Wook; Shin, Taeyoung; Hwang, Woo Suk

2013-12-01

188

Periimplantation-like growth and development of mouse blastocysts in medium containing horse serum.  

PubMed

Horse serum (HS) supported growth and differentiation of blastocysts as well as or better than fetal bovine serum (FBS) (p less than 0.01) as measured by a) the onset of trophoblastic outgrowth, b) the size of the resultant outgrowths, c) the size of nuclei in trophoblasts after their outgrowth and d) the size of the inner cell mass in outgrowths. Moreover, polyamines were found to be approximately 10-100 times less toxic to embryos when added to medium containing HS than when the medium contained FBS. PMID:6547912

Van Winkle, L J; Campione, A L

1984-09-15

189

Mothers, Workers and Students: Examining the Experiences of Single Mothers Transferring from Community Colleges into Universities  

ERIC Educational Resources Information Center

Single parent households are on the rise, and female headed households are more likely to live in poverty than other single parent households (Holyfield, 2002). Many single mothers who do not have an undergraduate degree see education as a way out of poverty (Holyfield, 2002; Heller & Bjorklund, 2004). This research was undertaken to highlight…

Robinson, Emily Erin Peterson

2010-01-01

190

Electronic Coupling Dependence of Ultrafast Interfacial Electron Transfer on Nanocrystalline Thin Films and Single Crystal  

SciTech Connect

The long-term goal of the proposed research is to understand electron transfer dynamics in nanoparticle/liquid interface. This knowledge is essential to many semiconductor nanoparticle based devices, including photocatalytic waste degradation and dye sensitized solar cells.

Lian, Tianquan

2014-04-22

191

Effect of Culture System on Developmental Competence, Cryosurvival and DNA-Fragmentation of In Vitro Bovine Blastocysts  

PubMed Central

Background This study investigated the effect of two in vitro embryo culture systems (co-culture system versus cell-free sequential-media) on developmental competence, cryosurvival and DNA- fragmentation of in vitro developed bovine blastocysts. Materials and Methods Bovine presumptive zygotes were cultured in Ménézo's B2 (B2) plus vero-cells or sequential synthetic oviductal fluid (SOF) for eight days. Subsequently, half of the expanded blastocysts developed in both groups were vitrified, warmed within 30 minutes and post- warming embryos along with their corresponding non-vitrified embryos were cultured for two additional days in the same medium used before vitrification. Embryo development, cryosurvival and apoptosis were compared between the groups. Results For non-vitrified embryos, culture in SOF significantly promoted the potency of embryos to develop into blastocysts compared with the co-culture system. The difference in post vitrification survival rate of SOF blastocysts (83.3%) was insignificant compared with co-culture (84.3%). However, while total cell number of warmed blastocysts in the co-culture system was significantly higher in the co-culture versus the sequential system (215.4 vs. 170.4), the quality of survived embryos in terms of hatching ability and apoptosis was adversely affected by co-culture compared with SOF (65.0% vs. 74.3%, and 13.5% vs. 10.0%, respectively; p<0.05). Conclusion Although co-culture system may increase the viability of embryos following cryopreservation, the potency and dynamics of blastocyst formation significantly increased with sequential media compared to the co-culture system which can compensate for the lower efficiency of sequential media for vitrification/warming purposes. PMID:24917920

Hajian, Mahdi; Hosseini, Seyed Morteza; Asgari, Vajiheh; Ostadhoosseini, Somayyeh; Forouzanfar, Mohsen; Nasr Esfahani, Mohammad Hossein

2011-01-01

192

The interfering effects of superovulation and vitrification upon some important epigenetic biomarkers in mouse blastocyst.  

PubMed

Appropriate epigenetic changes in preimplantation embryos are critical for embryonic development and successful pregnancy. The aim of this study was to evaluate the effects of some assisted reproductive techniques (ARTs) on a panel of epigenetic biomarkers by immunofluorescence staining at blastocyst stage. For this purpose, four treatment groups were designed: control (C), superovulation (S), superovulation+in vitro culture (SI), and superovulation+vitrification+in vitro culture (SVI). Results showed that vitrification decreased the developmental competence of embryos cultured in vitro (P<0.05). Semi-quantitative analysis revealed that vitrification decreased the fluorescence intensity of global DNA methylation in the inner cell mass (ICM), in SVI Group in comparison to C group (P<0.05). Superovulation, elevated the level of H3K9acetylation of trophectoderm (TE) in comparison to C and SI groups (P<0.05). Furthermore, ARTs manipulations influenced H3K9acetylation in the ICM (P<0.05). The fluorescence intensity of H4K12acetylation in TE for SVI group was higher than C and S (P<0.05). For H3K4tri-methylation, S group had higher fluorescence intensity in the ICM in comparison to SI and SVI (P<0.05). Finally, in vitro culture decreased Pou5f1 protein signal in comparison to in vivo-derived embryos at blastocyst stage (P<0.05). In conclusion, ART manipulations may have important influences on multiple epigenetic biomarkers. PMID:25307438

Bakhtari, Azizollah; Rahmani, Hamid-Reza; Bonakdar, Elham; Jafarpour, Farnoosh; Asgari, Vajiheh; Hosseini, Sayyed-Mortaza; Hajian, Mehdi; Edriss, Mohammad-Ali; Nasr-Esfahani, Mohammad-Hossein

2014-12-01

193

Lysophosphatidic Acid Signaling in Late Cleavage and Blastocyst Stage Bovine Embryos  

PubMed Central

Lysophosphatidic acid (LPA) is a known cell signaling lipid mediator in reproductive tissues. In the cow, LPA is involved in luteal and early pregnancy maintenance. Here, we evaluated the presence and role of LPA in bovine early embryonic development. In relevant aspects, bovine embryos reflect more closely the scenario occurring in human embryos than the mouse model. Transcription of mRNA and protein expression of enzymes involved in LPA synthesis (ATX and cPLA2) and of LPA receptors (LPAR1–4) were detected in Days 5 and 8 in vitro produced embryos. Embryonic LPA production into culture medium was also detected at both stages of development. Supplementation of culture medium with LPA (10?5?M) between Days 2 and 8 had no effect on embryo yield and quality and on blastocyst relative mRNA abundance of genes involved in prostaglandin synthesis (PTGS2, PGES, and PGFS) and steroidogenesis (3?HSD). However, LPA treatment affected transcription levels of embryo quality markers, decreasing BAX (apoptotic) and increasing BCL2 (antiapoptotic) and IGF2R (growth marker) gene transcription levels. Blastocyst transcription of OCT4 (pluripotency marker) was not affected by LPA stimulation. In conclusion, LPA is an early bovine embryonic autocrine/paracrine signaling mediator, and LPA action may be relevant in early embryo-maternal interactions leading to embryonic survival. PMID:24833815

Torres, Ana Catarina; Boruszewska, Dorota; Batista, Mariana; Kowalczyk-Zieba, Ilona; Sinderewicz, Emilia; Saulnier-Blache, Jean Sebastian; Woclawek-Potocka, Izabela; Lopes-da-Costa, Luis

2014-01-01

194

Transcriptome Profiling of Rabbit Parthenogenetic Blastocysts Developed under In Vivo Conditions  

PubMed Central

Parthenogenetic embryos are one attractive alternative as a source of embryonic stem cells, although many aspects related to the biology of parthenogenetic embryos and parthenogenetically derived cell lines still need to be elucidated. The present work was conducted to investigate the gene expression profile of rabbit parthenote embryos cultured under in vivo conditions using microarray analysis. Transcriptomic profiles indicate 2541 differentially expressed genes between parthenotes and normal in vivo fertilised blastocysts, of which 76 genes were upregulated and 16 genes downregulated in in vivo cultured parthenote blastocyst, using 3 fold-changes as a cut-off. While differentially upregulated expressed genes are related to transport and protein metabolic process, downregulated expressed genes are related to DNA and RNA binding. Using microarray data, 6 imprinted genes were identified as conserved among rabbits, humans and mice: GRB10, ATP10A, ZNF215, NDN, IMPACT and SFMBT2. We also found that 26 putative genes have at least one member of that gene family imprinted in other species. These data strengthen the view that a large fraction of genes is differentially expressed between parthenogenetic and normal embryos cultured under the same conditions and offer a new approach to the identification of imprinted genes in rabbit. PMID:23251477

Naturil-Alfonso, Carmen; Saenz-de-Juano, María dels Desamparats; Peñaranda, David S.

2012-01-01

195

Insulin growth factor adjustment in preimplantation rabbit blastocysts and uterine tissues in response to maternal type 1 diabetes.  

PubMed

Insulin-like growth factors (IGFs) are well-known regulators of embryonic growth and differentiation. IGF function is closely related to insulin action. IGFs are available to the preimplantation embryo through maternal blood (endocrine action), uterine secretions (paracrine action) and by the embryo itself (autocrine action). In rabbit blastocysts, embryonic IGF1 and IGF2 are specifically strong in the embryoblast (ICM). Signalling of IGFs and insulin in blastocysts follows the classical pathway with Erk1/2 and Akt kinase activation. The aim of this study was to analyse signalling of IGFs in experimental insulin dependent diabetes (exp IDD) in pregnancy, employing a diabetic rabbit model with uterine hypoinsulinemia and hyperglycaemia. Exp IDD was induced in female rabbits by alloxan treatment prior to mating. At 6 days p.c., the maternal and embryonic IGFs were quantified by RT-PCR and ELISA. In pregnant females, hepatic IGF1 expression and IGF1 serum levels were decreased while IGF1 and IGF2 were increased in endometrium. In blastocysts, IGF1 RNA and protein was approx. 7.5-fold and 2-fold higher, respectively, than in controls from normoglycemic females. In cultured control blastocysts supplemented with IGF1 or insulin in vitro for 1 or 12 h, IGF1 and insulin receptors as well as IGF1 and IGF2 were downregulated. In cultured T1D blastocysts activation of Akt and Erk1/2 was impaired with lower amounts of total Akt and Erk1/2 protein and a reduced phosphorylation capacity after IGF1 supplementation. Our data show that the IGF axis is severely altered in embryo-maternal interactions in exp IDD pregnancy. Both, the endometrium and the blastocyst produce more IGF1 and IGF2. The increased endogenous IGF1 and IGF2 expression by the blastocyst compensates for the loss of systemic insulin and IGF. However, this counterbalance does not fill the gap of the reduced insulin/IGF sensitivity, leading to a developmental delay of blastocysts in exp IDD pregnancy. PMID:22465205

Thieme, René; Schindler, Maria; Ramin, Nicole; Fischer, Sünje; Mühleck, Britta; Fischer, Bernd; Navarrete Santos, Anne

2012-07-01

196

Use of the 2A Peptide for Generation of Multi-Transgenic Pigs through a Single Round of Nuclear Transfer  

PubMed Central

Multiple genetic modifications in pigs can essentially benefit research on agriculture, human disease and xenotransplantation. Most multi-transgenic pigs have been produced by complex and time-consuming breeding programs using multiple single-transgenic pigs. This study explored the feasibility of producing multi-transgenic pigs using the viral 2A peptide in the light of previous research indicating that it can be utilized for multi-gene transfer in gene therapy and somatic cell reprogramming. A 2A peptide-based double-promoter expression vector that mediated the expression of four fluorescent proteins was constructed and transfected into primary porcine fetal fibroblasts. Cell colonies (54.3%) formed under G418 selection co-expressed the four fluorescent proteins at uniformly high levels. The reconstructed embryos, which were obtained by somatic cell nuclear transfer and confirmed to express the four fluorescent proteins evenly, were transplanted into seven recipient gilts. Eleven piglets were delivered by two gilts, and seven of them co-expressed the four fluorescent proteins at equivalently high levels in various tissues. The fluorescence intensities were directly observed at the nose, hoof and tongue using goggles. The results suggest that the strategy of combining the 2A peptide and double promoters efficiently mediates the co-expression of the four fluorescent proteins in pigs and is hence a promising methodology to generate multi-transgenic pigs by a single nuclear transfer. PMID:21603633

Deng, Wei; Yang, Dongshan; Zhao, Bentian; Ouyang, Zhen; Song, Jun; Fan, Nana; Liu, Zhaoming; Zhao, Yu; Wu, Qinghong; Nashun, Bayaer; Tang, Jiangjing; Wu, Zhenfang; Gu, Weiwang; Lai, Liangxue

2011-01-01

197

Single-phase convective heat transfer in microchannels: a review of experimental results  

Microsoft Academic Search

A bibliographical review on the convective heat transfer through microchannels is presented. The available experimental works quoted in the open literature are critically analysed in order to highlight the main results obtained on the friction factor, on the laminar-to-turbulent transition and on the Nusselt number in channels having a hydraulic diameter less than 1 mm. A comparison of the experimental

Gian Luca Morini

2004-01-01

198

Single crystalline BaTiO3 thin films synthesized using ion implantation induced layer transfer  

E-print Network

microscopy shows that the layer transferred thin films are ferroelectric, with domain structures.1063/1.2786915 I. INTRODUCTION Ferroelectric materials have attracted increased attention as device materials to large displace- ment and high output force during actuation.2 Many different methods have been studied

Atwater, Harry

199

HMM-BASED SEPARATION OF ACOUSTIC TRANSFER FUNCTION FOR SINGLE-CHANNEL SOUND SOURCE LOCALIZATION  

E-print Network

this estimation without measuring impulse responses. The frame sequence of the acoustic transfer function of a room impulse response. Then, for each test data set, we find a maximum-likelihood GMM from among arrays have been tried in order to localize sound sources. Conventional techniques, such as MUSIC, CSP

Takiguchi, Tetsuya

200

Oxidative catalysis using the stoichiometric oxidant as a reagent: an efficient strategy for single-electron-transfer-induced tandem anion-radical reactions.  

PubMed

Oxidative single-electron transfer-catalyzed tandem reactions consisting of a conjugate addition and a radical cyclization are reported, which incorporate the mandatory terminal oxidant as a functionality into the product. PMID:25070407

Kafka, František; Holan, Martin; Hidasová, Denisa; Pohl, Radek; Císa?ová, Ivana; Klepetá?ová, Blanka; Jahn, Ullrich

2014-09-01

201

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging  

PubMed Central

Microbial fuel cells (MFCs) represent a promising approach for sustainable energy production as they generate electricity directly from metabolism of organic substrates without the need for catalysts. However, the mechanisms of electron transfer between microbes and electrodes, which could ultimately limit power extraction, remain controversial. Here we demonstrate optically transparent nanoelectrodes as a platform to investigate extracellular electron transfer in Shewanella oneidensis MR-1, where an array of nanoholes precludes or single window allows for direct microbe-electrode contacts. Following addition of cells, short-circuit current measurements showed similar amplitude and temporal response for both electrode configurations, while in situ optical imaging demonstrates that the measured currents were uncorrelated with the cell number on the electrodes. High-resolution imaging showed the presence of thin, 4- to 5-nm diameter filaments emanating from cell bodies, although these filaments do not appear correlated with current generation. Both types of electrodes yielded similar currents at longer times in dense cell layers and exhibited a rapid drop in current upon removal of diffusible mediators. Reintroduction of the original cell-free media yielded a rapid increase in current to ?80% of original level, whereas imaging showed that the positions of > 70% of cells remained unchanged during solution exchange. Together, these measurements show that electron transfer occurs predominantly by mediated mechanism in this model system. Last, simultaneous measurements of current and cell positions showed that cell motility and electron transfer were inversely correlated. The ability to control and image cell/electrode interactions down to the single-cell level provide a powerful approach for advancing our fundamental understanding of MFCs. PMID:20837546

Jiang, Xiaocheng; Hu, Jinsong; Fitzgerald, Lisa A.; Biffinger, Justin C.; Xie, Ping; Ringeisen, Bradley R.; Lieber, Charles M.

2010-01-01

202

A simplified one-step nuclear transfer procedure alters the gene expression patterns and developmental potential of cloned porcine embryos  

PubMed Central

Various somatic cell nuclear transfer (SCNT) techniques for mammalian species have been developed to adjust species-specific procedures to oocyte-associated differences among species. Species-specific SCNT protocols may result in different expression levels of developmentally important genes that may affect embryonic development and pregnancy. In the present study, porcine oocytes were treated with demecolcine that facilitated enucleation with protruding genetic material. Enucleation and donor cell injection were performed either simultaneously with a single pipette (simplified one-step SCNT; SONT) or separately with different pipettes (conventional two-step SCNT; CTNT) as the control procedure. After blastocysts from both groups were cultured in vitro, the expression levels of developmentally important genes (OCT4, NANOG, EOMES, CDX2, GLUT-1, PolyA, and HSP70) were analyzed by real-time quantitative polymerase chain reaction. Both the developmental rate according to blastocyst stage as well as the expression levels CDX2, EOMES, and HSP70 were elevated with SONT compared to CTNT. The genes with elevated expression are known to influence trophectoderm formation and heat stress-induced arrest. These results showed that our SONT technique improved the development of SCNT porcine embryos, and increased the expression of genes that are important for placental formation and stress-induced arrest. PMID:23820223

Park, Sang Kyu

2014-01-01

203

The performance of single-and multi-proxy transfer functions (testate amoebae, bryophytes, vascular plants) for reconstructing mire surface wetness and pH  

E-print Network

The performance of single- and multi-proxy transfer functions (testate amoebae, bryophytes amoebae Transfer function Quantitative paleoecology Monitoring Water table depth pH Peatlands are widely to infer peatland depth to the water table (DWT) and pH based on testate amoeba (percentages, or presence

Bern, Universität

204

Recent advances in the chemoselective reduction of functional groups mediated by samarium(II) iodide: a single electron transfer approach.  

PubMed

Recently, samarium(II) iodide reductants have emerged as powerful single electron donors for the highly chemoselective reduction of common functional groups. Complete control of the product formation can be achieved on the basis of a judicious choice of a Sm(II) complex/proton donor couple, even in the presence of extremely sensitive functionalities (iodides, aldehydes). In most cases, the reductions are governed by thermodynamic control of the first electron transfer, which opens up new prospects for unprecedented transformations via radical intermediates under mild regio-, chemo- and diastereoselective conditions that are fully orthogonal to hydrogenation or metal-hydride mediated processes. PMID:24013846

Szostak, Michal; Spain, Malcolm; Procter, David J

2013-12-01

205

Theoretical and simulation tools for electron transfer and chain reactions in single walled carbon nanotubes  

E-print Network

Single walled carbon nanotubes (SWNT) are cylindrical sheets of graphene whose electronic structures and diameters are determined by their chiralities. Current synthetic methods produce batches of nanotubes containing a ...

Nair, Nitish

2009-01-01

206

Harvesting and Transferring Vertical Pillar Arrays of Single-Crystal Semiconductor Devices to Arbitrary Substrates  

Microsoft Academic Search

Development of devices that can be fabricated on amorphous substrates using multiple single-crystal semiconductors with different physical, electrical, and optical characteristics is important for highly efficient portable and flexible electronics, optoelectronics, and energy conversion devices. Reducing the use of single-crystal substrates can contribute to low-cost and environmentally benign devices covering a large area. We demonstrate a technique to harvest and

V. J. Logeeswaran; Aaron M. Katzenmeyer; M. Saif Islam

2010-01-01

207

Transfer of self-aligned spacer patterns for single-digit nanofabrication.  

PubMed

We report the transfer of sub-10 nm half-pitch grating patterns created through a combination of block copolymer directed self-assembly and sidewall spacer-based self-aligned double patterning into Si substrates. Low substrate bias reactive ion etching of TiOx conformally deposited onto carbon mandrels using atomic layer deposition renders distinct, pitch-halved spacers with minimal etch byproduct redeposition. Independent spacer and mandrel width control and the use of an underlying CrNx hard mask deposited by reactive sputtering facilitates etching of Si lines with low roughness and fine placement control. The insights into pattern transfer presented here are directly applicable to the fabrication of rectangular bit pattern nanoimprint templates at densities above 1.5 Td in(-2). PMID:25656564

Doerk, Gregory S; Gao, He; Wan, Lei; Lille, Jeff; Patel, K C; Chapuis, Yves-Andre; Ruiz, Ricardo; Albrecht, Thomas R

2015-02-27

208

Blocking Single-Stranded Transferred DNA Conversion to Double-Stranded Intermediates by Overexpression of Yeast DNA REPLICATION FACTOR A.  

PubMed

Agrobacterium tumefaciens delivers its single-stranded transferred DNA (T-strand) into the host cell nucleus, where it can be converted into double-stranded molecules. Various studies have revealed that double-stranded transfer DNA (T-DNA) intermediates can serve as substrates by as yet uncharacterized integration machinery. Nevertheless, the possibility that T-strands are themselves substrates for integration cannot be ruled out. We attempted to block the conversion of T-strands into double-stranded intermediates prior to integration in order to further investigate the route taken by T-DNA molecules on their way to integration. Transgenic tobacco (Nicotiana benthamiana) plants that overexpress three yeast (Saccharomyces cerevisiae) protein subunits of DNA REPLICATION FACTOR A (RFA) were produced. In yeast, these subunits (RFA1-RFA3) function as a complex that can bind single-stranded DNA molecules, promoting the repair of genomic double strand breaks. Overexpression of the RFA complex in tobacco resulted in decreased T-DNA expression, as determined by infection with A. tumefaciens cells carrying the ?-glucuronidase intron reporter gene. Gene expression was not blocked when the reporter gene was delivered by microbombardment. Enhanced green fluorescent protein-assisted localization studies indicated that the three-protein complex was predominantly nuclear, thus indicating its function within the plant cell nucleus, possibly by binding naked T-strands and blocking their conversion into double-stranded intermediates. This notion was further supported by the inhibitory effect of RFA expression on the cell-to-cell movement of Bean dwarf mosaic virus, a single-stranded DNA virus. The observation that RFA complex plants dramatically inhibited the transient expression level of T-DNA and only reduced T-DNA integration by 50% suggests that double-stranded T-DNA intermediates, as well as single-stranded T-DNA, play significant roles in the integration process. PMID:25424309

Dafny-Yelin, Mery; Levy, Avner; Dafny, Raz; Tzfira, Tzvi

2015-01-01

209

TallyHO obese female mice experience poor reproductive outcomes and abnormal blastocyst metabolism that is reversed by metformin.  

PubMed

Obese women experience worse reproductive outcomes than normal weight women, specifically infertility, pregnancy loss, fetal malformations and developmental delay of offspring. The aim of the present study was to use a genetic mouse model of obesity to recapitulate the human reproductive phenotype and further examine potential mechanisms and therapies. New inbred, polygenic Type 2 diabetic TallyHO mice and age-matched control C57BL/6 mice were superovulated to obtain morula or blastocyst stage embryos that were cultured in human tubal fluid (HTF) medium. Deoxyglucose uptake was determined for individual insulin-stimulated blastocysts. Apoptosis was detected by confocal microscopy using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay and Topro-3 nuclear dye. Embryos were scored for TUNEL-positive as a percentage of total nuclei. AMP-activated protein kinase (AMPK) activation, tumour necrosis factor (TNF)-? expression and adiponectin expression were analysed by western immunoblot and confocal immunofluorescent microscopy. Lipid accumulation was assayed by BODIPY. Comparisons were made between TallyHO morulae cultured to blastocyst embryos in either HTF medium or HTF medium with 25?gmL(-1) metformin. TallyHO mice developed whole body abnormal insulin tolerance, had decreased litter sizes and increased non-esterified fatty acid levels. Blastocysts from TallyHO mice exhibited increased apoptosis, decreased insulin sensitivity and decreased AMPK. A possible cause for the insulin resistance and abnormal AMPK phosphorylation was the increased TNF-? expression and lipid accumulation, as detected by BODIPY, in TallyHO blastocysts and decreased adiponectin. Culturing TallyHO morulae with the AMPK activator metformin led to a reversal of all the abnormal findings, including increased AMPK phosphorylation, improved insulin-stimulated glucose uptake and normalisation of lipid accumulation. Women with obesity and insulin resistance experience poor pregnancy outcomes. Previously we have shown in mouse models of insulin resistance that AMPK activity is decreased and that activators of AMPK reverse poor embryo outcomes. Here, we show for the first time using a genetically altered obese model, not a diet-induced model, that metformin reverses many of the adverse effects of obesity at the level of the blastocyst. Expanding on this we determine that activation of AMPK via metformin reduces lipid droplet accumulation, presumably by eliminating the inhibitory effects of TNF-?, resulting in normalisation of fatty acid oxidation and HADH2 (hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), alpha subunit) activity. Metformin exposure in vitro was able to partially reverse these effects, at the level of the blastocyst, and may thus be effective in preventing the adverse effects of obesity on pregnancy and reproductive outcomes. PMID:25472042

Louden, Erica D; Luzzo, Kerri M; Jimenez, Patricia T; Chi, Tiffany; Chi, Maggie; Moley, Kelle H

2014-12-01

210

Quantitative description of the lie-to-sit-to-stand-to-walk transfer by a single body-fixed sensor.  

PubMed

Sufficient capacity and quality of performance of complex movement patterns during daily activity, such as standing up from a bed, is a prerequisite for independent living and also may be an indicator of fall risk. Until now, the transfer from lying-to-sit-to-stand-to-walk (LSSW) was investigated by functional testing, subjective rating or for activity classification of subtasks. The aim of this study was to use a single body-fixed inertial sensor to describe the complex movement of the LSSW transfer. Fifteen older patients of a geriatric rehabilitation clinic (median age 81 years) and ten young, healthy persons (median age 37 years) were instructed to stand up from bed in a continuous movement and to start walking. Data acquisition was performed using an inertial measurement unit worn on the lower back. Parameters extracted from the sensor outputs were able to correctly classify the subjects into a correct group with sensitivity and specificity between 90% and 100%. ICCs 3,1 of the descriptive parameters ranged between 0.85 and 0.95 in the cohort of older patients. The different strategies adopted to transfer from lying to standing up were estimated through an extended Kalman filter. The results obtained in this study suggest the usability of the instrumented LSSW test in clinical settings. PMID:23221832

Bagalà, Fabio; Klenk, Jochen; Cappello, Angelo; Chiari, Lorenzo; Becker, Clemens; Lindemann, Ulrich

2013-07-01

211

SCC-DFTB Energy Barriers for Single and Double Proton Transfer Processes in the Model Molecular Systems Malonaldehyde and Porphycene  

SciTech Connect

Self-consistent charge-density functional tight-binding SCC-DFTB is a computationally efficient method applicable to large (bio)molecular systems in which (bio)chemical reactions may occur. Among these reactions are proton transfer processes. This method, along with more advanced ab initio techniques, is applied in this study to compute intramolecular barriers for single and double proton transfer processes in the model systems, malonaldehyde and porphycene, respectively. SCC-DFTB is compared with experimental data and higher-level ab initio calculations. For malonaldehyde, the SCC-DFTB barrier height is 3.1 kcal/mol in vacuo and 4.2 kcal/mol in water solution. In the case of porphycene, the minimum energy pathways for double intramolecular proton transfer were determined using the conjugate peak refinement (CPR) method. Six isomers of porphycene were ordered according to energy. The only energetically allowed pathway was found to connect two symmetrical trans states via an unstable cis-A isomer. The SCC-DFTB barrier heights are 11.1 kcal/mol for the trans-cis-A process, and 7.4 kcal/mol for the reverse cis-A-trans one with the energy difference of 3.7 kcal/mol between the trans- and cis-A states. The method provides satisfactory energy results when compared with reference ab initio and experimental data.

Walewski, L. [Warsaw University; Krachtus, D [University of Heidelberg; Fischer, S. [University of Heidelberg; Smith, Jeremy C [ORNL; Bala, P. [Institute of Physics, Nicolaus Copernicus University, Toru?, Poland; Lesyng, B. [Warsaw University

2005-09-01

212

Photofragmentation in linked donor-acceptor molecules. Intramolecular single electron transfer induced cleavage of a 1,2-diamine  

SciTech Connect

Two intramolecular donor-acceptor molecules which fragment by a single electron transfer initiated cation radical carbon-carbon bond cleavage have been synthesized and their photoreactivity studied. The intramolecular [open quotes]diads[close quotes] consist of a 1,2-diamine linked via an ester bond to either an anthraquinone or a 9,10-dicyanoanthracene electron-acceptor chromophore. As the covalent linkage between the donor and acceptor chromophores prevents solvent separation of the photogenerated radical ion pair, these systems provide a [open quotes]clock[close quotes] to examine directly competition between fragmentation and back electron transfer. The linked anthraquinone molecule fragments efficiently, with quantum yields approaching 80%, despite the inability of the photoproduced radical ions to separate. These high yields may be attributed to a slow, spin-forbidden back electron transfer and a rapid fragmentation. In contrast, the quantum yields for the dicyanoanthracene diad (reactive singlet) are markedly lower, less than 0.001 in benzene. The reactivity of comparable intermolecular donor-acceptor combinations is also reported. 54 refs., 3 figs., 2 tabs.

Leon, J.W.; Whitten, D.G. (Univ. of Rochester, NY (United States))

1993-09-08

213

Serial transfer of single-cell-derived immunocompetence reveals stemness of CD8(+) central memory T cells.  

PubMed

Maintenance of immunological memory has been proposed to rely on stem-cell-like lymphocytes. However, data supporting this hypothesis are focused on the developmental potential of lymphocyte populations and are thus insufficient to establish the functional hallmarks of stemness. Here, we investigated self-renewal capacity and multipotency of individual memory lymphocytes by in vivo fate mapping of CD8(+) T cells and their descendants across three generations of serial single-cell adoptive transfer and infection-driven re-expansion. We found that immune responses derived from single naive T (Tn) cells, single primary, and single secondary central memory T (Tcm) cells reached similar size and phenotypic diversity, were subjected to comparable stochastic variation, and could ultimately reconstitute immunocompetence against an otherwise lethal infection with the bacterial pathogen Listeria monocytogenes. These observations establish that adult tissue stem cells reside within the CD62L(+) Tcm cell compartment and highlight the promising therapeutic potential of this immune cell subset. PMID:25035956

Graef, Patricia; Buchholz, Veit R; Stemberger, Christian; Flossdorf, Michael; Henkel, Lynette; Schiemann, Matthias; Drexler, Ingo; Höfer, Thomas; Riddell, Stanley R; Busch, Dirk H

2014-07-17

214

An experimental investigation of heat transfer and flow friction characteristics of louvered fin surfaces by the modified single blow technique  

NASA Astrophysics Data System (ADS)

This paper describes the development of an experimental facility to determine the heat transfer and flow friction characteristics of heat exchange surfaces by the modified single blow technique and the application of this transient technique to evaluate the performance characteristics of louvered fin heat exchangers. The reliability of implementing the modified single blow technique on the developed test facility is borne out by the good agreement in the heat transfer and flow friction data for the parallel plate test core when compared with theoretical and empirical correlations available in the literature. Performance evaluation of two louvered fin surfaces used mainly for cooling of large land and marine based electrical power generator sets is carried out and compared with similar louvered fin surfaces available in the literature. On the basis of dimensionless area and power factors, it was found that the flat fin is slightly superior in overall performance than its corrugated counterpart for low Reynolds numbers. Both surfaces are however inferior in performance when compared with the flat fin surface of Achaichia and Cowell and the corrugated fin surface of Davenport. Use of the j/f ratio as an approximate figure of merit led to an inaccurate assessment of the performance of the louvered fin heat exchanger surfaces evaluated in this study.

Leong, K. C.; Toh, K. C.

215

Study of Sequential Dexter Energy Transfer in High Efficient Phosphorescent White Organic Light-Emitting Diodes with Single Emissive Layer  

PubMed Central

In this study, we report our effort to realize high performance single emissive layer three color white phosphorescent organic light emitting diodes (PHOLEDs) through sequential Dexter energy transfer of blue, green and red dopants. The PHOLEDs had a structure of; ITO(1500 Å)/NPB(700 Å)/mCP:Firpic-x%:Ir(ppy)3-0.5%:Ir(piq)3-y%(300 Å)/TPBi(300 Å)/Liq(20 Å)/Al(1200 Å). The dopant concentrations of FIrpic, Ir(ppy)3 and Ir(piq)3 were adjusted and optimized to facilitate the preferred energy transfer processes attaining both the best luminous efficiency and CIE color coordinates. The presence of a deep trapping center for charge carriers in the emissive layer was confirmed by the observed red shift in electroluminescent spectra. White PHOLEDs, with phosphorescent dopant concentrations of FIrpic-8.0%:Ir(ppy)3-0.5%:Ir(piq)3-0.5% in the mCP host of the single emissive layer, had a maximum luminescence of 37,810?cd/m2 at 11?V and a luminous efficiency of 48.10?cd/A at 5?V with CIE color coordinates of (0.35, 0.41). PMID:25388087

Kim, Jin Wook; You, Seung Il; Kim, Nam Ho; Yoon, Ju-An; Cheah, Kok Wai; Zhu, Fu Rong; Kim, Woo Young

2014-01-01

216

Amino Acid Supplementation Affects Imprinted Gene Transcription Patterns in Parthenogenetic Porcine Blastocysts  

PubMed Central

To determine whether exogenous amino acids affect gene transcription patterns in parthenogenetic porcine embryos, we investigated the effects of amino acid mixtures in culture medium. Parthenogenetic embryos were cultured in PZM3 medium under four experimental conditions: 1) control (no amino acids except L-glutamine and taurine); 2) nonessential amino acids (NEAA); 3) essential amino acids (EAA); and 4) NEAA and EAA. The rate of development of embryos to the four-cell stage was not affected by treatment. However, fewer (P<0.05) embryos cultured with EAA (12.8%) reached the blastocyst stage as compared with the control group (25.6%) and NEAA group (30.3%). Based on these findings, we identified genes with altered expression in parthenogenetic embryos exposed to medium with or without EAAs. The results indicated that EAA influenced gene expression patterns, particularly those of imprinted genes (e.g., H19, IGF2R, PEG1, XIST). However, NEAAs did not affect impaired imprinted gene expressions induced by EAA. The results also showed that mechanistic target of rapamycin (MTOR) mRNA expression was significantly increased by EAA alone as compared with control cultures, and that the combined treatment with NEAA and EAA did not differ significantly from those of control cultures. Our results revealed that gene transcription levels in porcine embryos changed differentially depending on the presence of EAA or NEAA. However, the changes in the H19 mRNA observed in the parthenogenetic blastocysts expression level was not related to the DNA methylation status in the IGF2/H19 domain. The addition of exogenous amino acid mixtures affected not only early embryonic development, but also gene transcription levels, particularly those of imprinted genes. However, this study did not reveal how amino acids affect expression of imprinted genes under the culture conditions used. Further studies are thus required to fully evaluate how amino acids affect transcriptional regulation in porcine embryos. PMID:25180972

Park, Chi-Hun; Jeong, Young-Hee; Jeong, Yeun-Ik; Kwon, Jeong-Woo; Shin, Taeyoung; Hyun, Sang-Hwan; Jeung, Eui-Bae; Kim, Nam-Hyung; Seo, Sang-Kyo; Lee, Chang-Kyu; Hwang, Woo-Suk

2014-01-01

217

Charge Transfer in Single Chains of a Donor–Acceptor Conjugated Tri-Block Copolymer  

E-print Network

. Experimental: A central poly-(4-(9,9-dioctyl-9H-fluoren-2-yl)benzo[c][1,2,5]-thiadiazole) (F8BT) electron- accepting block was synthesised by Suzuki condensation, followed by endcapping with trimethylsilylpheny groups and reaction with ICl. The block size... to theoretical patterns calculated as described elsewhere.29,30 Results and discussion: Donor-acceptor block copolymers must have appropriate energy levels and redox properties to allow for effective charge transfer; in this case from the electron donor...

Hooley, Emma N.; Jones, David J.; Greenham, Neil C.

2014-11-24

218

Probing Single-Neutron Levels in 127,129Sn via Transfer Reactions  

NASA Astrophysics Data System (ADS)

The (d,p) reaction was measured with radioactive ion beams of 126Sn and 128Sn (~5 MeV/u) in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, utilizing the SuperORRUBA silicon detector array. Angular distributions of reaction protons were measured for several states in 127Sn and 129Sn in order to determine angular momentum transfers and deduce spectroscopic factors. Combined with previous experiments on 130Sn and 132Sn, these results provide a complete set of (d,p) reaction data on even tin isotopes between stable 124Sn and doubly magic 132Sn.

Manning, B.; Cizewski, J. A.; Howard, M. E.; O'Malley, P. D.; Ratkiewicz, A.; Kozub, R. L.; Ahn, S.; Jones, K. L.; Pittman, S. T.; Allmond, J. M.; Bardayan, D. W.; Beene, J. R.; Galindo-Uribarri, A.; Liang, J. F.; Nesaraja, C. D.; Pain, S. D.; Radford, D. C.; Schmitt, K. T.; Shapira, D.; Smith, M. S.; Chae, K. Y.; Chipps, K. A.; Matos, M.; Padilla-Rodal, E.; Peters, W. A.

2014-09-01

219

Studies of Nuclei Close to 132Sn Using Single-Neutron Transfer Reactions  

SciTech Connect

Neutron transfer reactions were performed in inverse kinematics using radioactive ion beams of 132Sn, 130Sn, and 134Te and deuterated polyethylene targets. Preliminary results are presented. The Q-value spectra for 133Sn, 131Sn and 135Te reveal a number of previously unobserved peaks. The angular distributions are compatible with the expected lf7/2 nature of the ground state of 133Sn, and 2p3/2 for the 3.4 MeV state in 131Sn.

Jones, K. L. [University of Tennessee, Knoxville (UTK); Pain, S. D. [Rutgers University; Kozub, R. L. [Tennessee Technological University; Adekola, Aderemi S [ORNL; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Catford, Wilton N [ORNL; Chae, K. Y. [University of Tennessee, Knoxville (UTK); Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Erikson, Luke [Colorado School of Mines, Golden; Gaddis, A. L. [Furman University; Greife, U. [Colorado School of Mines, Golden; Grzywacz, R. K. [University of Tennessee, Knoxville (UTK); Harlin, Christopher W [ORNL; Hatarik, Robert [Rutgers University; Howard, Joshua A [ORNL; James, J. [Colorado School of Mines, Golden; Kapler, R. [University of Tennessee, Knoxville (UTK); Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Ma, Zhanwen [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O'Malley, Patrick [Rutgers University; Patterson, N. P. [University of Surrey, UK; Paulauskas, Stanley [University of Tennessee, Knoxville (UTK); Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Sikora, M. [Rutgers University; Sissom, D. J. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University; Wilson, Gemma L [ORNL

2009-01-01

220

Transcervical Embryo Transfer in Horses: An Application in an Equestrian Teaching Center  

PubMed Central

Embryo transfer was used in an equestrian teaching center in order to produce as many foals as possible from their preferred mares during a single breeding season. Embryo collection by uterine lavage was attempted in five donor mares on 25 occasions 6.5 days after ovulation. Sixteen of the collection attempts (64%) yielded a total of 17 blastocysts. Of these 17 embryos, 13 were immediately transferred transcervically into recipient mares that had ovulated within two days of the time of ovulation in the donors, three were frozen for later transfer, and one was lost. Eight of the freshly transferred embryos (61%) developed and were detected on ultrasonography on day 11.5; five of these continued to develop normally and gave rise to healthy foals (38%), but three were lost at 14.5, 22.5 and 24.5 days gestation. Two of the frozen embryos were judged viable when thawed the following year and produced one additional pregnancy after transcervical transfer. Thus the five donor mares have produced five foals and a sixth 90-day pregnancy1 with only a three-month interruption of their use for competition and teaching. 1While this paper was in press, the sixth pregnancy also terminated in the production of a healthy foal. ImagesFigure 1.Figure 2. PMID:17422935

Sirois, Jean; Betteridge, Keith J.; Brault, A.

1987-01-01

221

Single-drop reactive extraction/extractive reaction with forced convective diffusion and interphase mass transfer  

NASA Technical Reports Server (NTRS)

An algorithm has been developed for the forced convective diffusion-reaction problem for convection inside and outside a droplet by a recirculating flow field hydrodynamically coupled at the droplet interface with an external flow field that at infinity becomes a uniform streaming flow. The concentration field inside the droplet is likewise coupled with that outside by boundary conditions at the interface. A chemical reaction can take place either inside or outside the droplet or reactions can take place in both phases. The algorithm has been implemented and results are shown here for the case of no reaction and for the case of an external first order reaction, both for unsteady behavior. For pure interphase mass transfer, concentration isocontours, local and average Sherwood numbers, and average droplet concentrations have been obtained as a function of the physical properties and external flow field. For mass transfer enhanced by an external reaction, in addition to the above forms of results, we present the enhancement factor, with the results now also depending upon the (dimensionless) rate of reaction.

Kleinman, Leonid S.; Reed, X. B., Jr.

1995-01-01

222

Single-drop reactive extraction/extractive reaction with forced convective diffusion and interphase mass transfer  

NASA Technical Reports Server (NTRS)

An algorithm has been developed for time-dependent forced convective diffusion-reaction having convection by a recirculating flow field within the drop that is hydrodynamically coupled at the interface with a convective external flow field that at infinity becomes a uniform free-streaming flow. The concentration field inside the droplet is likewise coupled with that outside by boundary conditions at the interface. A chemical reaction can take place either inside or outside the droplet, or reactions can take place in both phases. The algorithm has been implemented, and for comparison results are shown here for the case of no reaction in either phase and for the case of an external first order reaction, both for unsteady behavior. For pure interphase mass transfer, concentration isocontours, local and average Sherwood numbers, and average droplet concentrations have been obtained as a function of the physical properties and external flow field. For mass transfer enhanced by an external reaction, in addition to the above forms of results, we present the enhancement factor, with the results now also depending upon the (dimensionless) rate of reaction.

Kleinman, Leonid S.; Red, X. B., Jr.

1995-01-01

223

Molecular cytogenetic analysis of human blastocysts andcytotrophoblasts by multi-color FISH and Spectra Imaging analyses  

SciTech Connect

Numerical chromosome aberrations in gametes typically lead to failed fertilization, spontaneous abortion or a chromosomally abnormal fetus. By means of preimplantation genetic diagnosis (PGD), we now can screen human embryos in vitro for aneuploidy before transferring the embryos to the uterus. PGD allows us to select unaffected embryos for transfer and increases the implantation rate in in vitro fertilization programs. Molecular cytogenetic analyses using multi-color fluorescence in situ hybridization (FISH) of blastomeres have become the major tool for preimplantation genetic screening of aneuploidy. However, current FISH technology can test for only a small number of chromosome abnormalities and hitherto failed to increase the pregnancy rates as expected. We are in the process of developing technologies to score all 24 chromosomes in single cells within a 3 day time limit, which we believe is vital to the clinical setting. Also, human placental cytotrophoblasts (CTBs) at the fetal-maternal interface acquire aneuploidies as they differentiate to an invasive phenotype. About 20-50% of invasive CTB cells from uncomplicated pregnancies were found aneuploidy, suggesting that the acquisition of aneuploidy is an important component of normal placentation, perhaps limiting the proliferative and invasive potential of CTBs. Since most invasive CTBs are interphase cells and possess extreme heterogeneity, we applied multi-color FISH and repeated hybridizations to investigate individual CTBs. In summary, this study demonstrates the strength of Spectral Imaging analysis and repeated hybridizations, which provides a basis for full karyotype analysis of single interphase cells.

Weier, Jingly F.; Ferlatte, Christy; Baumgartner, Adolf; Jung,Christine J.; Nguyen, Ha-Nam; Chu, Lisa W.; Pedersen, Roger A.; Fisher,Susan J.; Weier, Heinz-Ulrich G.

2006-02-08

224

On the definition of dominant force regimes for flow boiling heat transfer by using single mini-tubes  

NASA Astrophysics Data System (ADS)

Recent increase in the size of space platforms requires the management of larger amount of waste heat under high heat flux conditions and the transportation of it along a long distance to the radiator. Flow boiling applied to the thermal management system in space attracts much attention as promising means to realize high-performance heat transfer and transport because of large latent heat of vaporization. In microgravity two-phase flow phenomena are quite different from those under 1-g condition because buoyancy effects are significantly reduced and surface tension becomes dominant. By the similar reason, flow boiling characteristics in mini channels are not the same as those in channels of normal sizes. In the present stage, however, the boundary between the regimes of body force dominated and of surface tension dominated is not clear. The design of space thermal devices, operated under the conditions where no effect of gravity is expected, will improve the reliability of their ground tests, provided that the boundaries of dominant force regimes are clarified quantitatively in advance. In flow boiling in mini channels or in parallel channels, back flow could be occurred because of rapid growth of bubbles in a confined space, resulting flow rate fluctuation. Flow boiling heat transfer characteristics in mini channels can be changed considerably by the existence of inlet flow rate fluctuation. It is important to pay attention to experimental accuracy and to use a single circular mini-tube to compare heat transfer characteristics with those of normal size tubes. In the present paper, effects of tube orientations, i.e. vertical upward flow, vertical downward flow and horizontal flow, on flow boiling heat transfer characteristics is investigated for FC72 flowing in single mini-tubes with inner diameters of 0.13 and 0.51 mm to establish a reliable dominant force regime map. If the regime map is described by using dimensionless groups of Bond, Weber and Froude numbers, the boundary of dominant forces of inertia and body force is examined by using the mini-tube of the larger diameter at constant Bond number Bo = 0.51, and the boundary of inertia and surface tension by using the mini-tube of smaller diameter at Bo = 0.033. The influence of inertia is varied by the change of vapor quality, i.e. ratio of vapor mass flow rate to the total, under constant mass velocities, where the velocity of liquid-vapor mixtures is increased with increasing vapor quality. For the tube diameter of 0.51 mm, under low inertia conditions at Froude number Fr < 5, heat transfer coefficients were influenced by the tube orientation, while the heat transfer coefficients were almost independent of the orientation for Fr > 5. The results indicated that the boundary between the body force dominated and the inertia force dominated regimes was given by Froude number as Fr ˜ 5. On the other hand, for tube diameter of 0.13 mm, almost no effect of tube = orientation was observed for all combinations of mass velocity and vapor quality, and heat transfer coefficients were independent of vapor quality under low inertia conditions at Weber number We < 5, and vice versa. The results implied the boundary between the surface tension dominated and the inertia force dominated regimes was represented by We ˜ 5. = In addition, by the reflection of both results on the two-dimensional regime map, the boundary between the surface tension dominated and the body force dominated regimes was approx-imately evaluated as Bo ˜ 0.25 from the crossing point of two boundary lines. This value = located in the range of 0.033 < Bo < 0.51 is consistent with the boundaries between the sur-face tension dominated and the body force dominated regimes classified for the smaller and larger mini-tubes, respectively, under low inertia conditions.

Baba, Soumei; Sawada, Kenichiro; Kubota, Chisato; Kawanami, Osamu; Asano, Hitoshi; Inoue, Koichi; Ohta, Haruhiko

225

Electron transfer between cytochrome c and cytochome c peroxidase in single crystals.  

PubMed

Cytochrome c (Cc) and cytochrome c peroxidase (CcP) form an important redox pair for understanding interprotein electron transfer (ET). Measurements of ET rates from photoexcited CcP substituted with Zn porphyrin to either yeast Fe(III)Cc or horse Fe(III)Cc in crystals reveal that the molecular associations found in the respective crystal structures determine solution reactivity. Similar forward rates for yeast isozyme-1 Cc (yCc) and yCc homologue horse Cc (hCc), despite different orientations relative to CcP, suggest small-amplitude conformational gating of ET even in the crystalline state; faster back ET in the yCc compared to the hCc complex agrees with the relative coupling between redox sites predicted by the structures. PMID:15339156

Kang, Seong A; Marjavaara, Pieti J; Crane, Brian R

2004-09-01

226

Optical characterization of nonlocal spin transfer torque acting on a single nanomagnet  

NASA Astrophysics Data System (ADS)

Time-resolved scanning Kerr microscopy (TRSKM) has been used to examine the effect of nonlocal spin transfer torque (NL-STT) within a two-terminal current perpendicular-to-plane nonlocal spin valve. A combination of Oersted field and NL-STT was used to excite and control the magnetization dynamics. By comparison with a macrospin model, the strength of the NL-STT was quantified and found to be comparable to that achieved by direct injection of spin-polarized current. The sensitivity of the magneto-optical probe to small out-of-plane deflections of the magnetization also allows the NL-STT to be quantified in quasi-dc measurements, greatly simplifying the investigation of STT phenomena.

Keatley, P. S.; Aziz, A.; Ali, M.; Hickey, B. J.; Blamire, M. G.; Hicken, R. J.

2014-03-01

227

Single nanoparticle collisions at microfluidic microband electrodes: the effect of electrode material and mass transfer.  

PubMed

We report on the effect of convection on electrochemically active collisions between individual Pt nanoparticles (PtNPs) and Hg and Au electrodes. Compared to standard electrochemical cells utilizing Hg and Au ultramicroelectrodes (UMEs) used in previous studies of electrocatalytic amplification, microelectrochemical devices offer two major advantages. First, the PtNP limit of detection (0.084 pM) is ?8 times lower than the lowest concentration measured using UMEs. Second, convection enhances the mass transfer of PtNPs to the electrode surface, which enhances the collision frequency from ?0.02 pM(-1) s(-1) on UMEs to ?0.07 pM(-1) s(-1) in microelectrochemical devices. We also show that the size of PtNPs can be measured in flowing systems using data from collision experiments and then validate this finding using multiphysics simulations. PMID:25360826

Alligrant, Timothy M; Anderson, Morgan J; Dasari, Radhika; Stevenson, Keith J; Crooks, Richard M

2014-11-11

228

Extracorporeal circulatory systems in the interhospital transfer of critically ill patients: experience of a single institution  

PubMed Central

BACKGROUND AND OBJECTIVES: Critically ill patients with acute circulatory failure cannot be moved to other institutions unless stabilized by mechanical support systems. Extracorporeal heart and lung assist systems are increasingly used as a bridge to end-organ recovery or transplantation, and as an ultimate rescue tool in cardiopulmonary resuscitation. PATIENTS AND METHODS: From July 2001 to April 2008, we had 38 requests for extracorporeal support for interhospital transfer carried out by the air medical service. Respiratory failure was present in 29 patients, who were provided with pumpless extracorporeal lung assist (PECLA) or veno-venous extracorporeal membrane oxygenation (ECMO). Cardiac failure dominated in 9 patients, who underwent implantation of extracorporeal life support (ECLS). Underlying diseases were acute respiratory distress syndrome in 15 patients, pneumonia in 7, prior lung transplant status in 4, cardiogenic shock in 7, and septic shock in 4. RESULTS: All assist systems were connected via peripheral vessels by the Seldinger technique. Transport was uneventful in all cases with no technical failures. On arrival at the specialized care hospital, two patients had leg ischemia and underwent relocation of the arterial cannula. After a mean (SD) support of 5.1 (3.0) days for PECLA, 3.5 (2.9) days for ECLS, and 7.3 (5.8) days for ECMO, 60%, 66%, and 66% of patients, respectively, could be successfully weaned from the systems. Discharge rates were 45% for PECLA, 44% for ECLS, and 56% for ECMO. CONCLUSION: Our experience proves that minimized extracorporeal assist devices allow safe assistance of patients with isolated or combined heart and lung failure in need of interhospital transfer. Critically ill patients get a chance to reach a center of maximum medical care. PMID:19318758

Haneya, Assad; Philipp, Alois; Foltan, Maik; Mueller, Thomas; Camboni, Daniele; Rupprecht, Leopold; Puehler, Thomas; Hirt, Stephan; Hilker, Michael; Kobuch, Reinhard; Schmid, Christof; Arlt, Matthias

2009-01-01

229

Radiant heat transfer from flames in a single tubular turbojet combustor / Leonard Topper  

NASA Technical Reports Server (NTRS)

An experimental investigation of thermal radiation from the flame of a single tubular turbojet-engine combustor to the combustor liner is presented. The effects of combustor inlet-air pressure, air mass flow, and fuel-air ratio on the radiant intensity and the temperature and emissivity of the flame are reported. The total radiation of the "luminous" flames (containing incandescent soot particles) was much greater (4 to 21 times) than the "nonluminous" molecular radiation. The intensity of radiation from the flame increased rapidly with an increase in combustor inlet-air pressure; it was affected to a lesser degree by variations in fuel-air ratio and air mass flow.

Topper, Leonard

1952-01-01

230

Combination of oocyte and zygote selection by brilliant cresyl blue (BCB) test enhanced prediction of developmental potential to the blastocyst in cattle.  

PubMed

The cumulus oocyte complexes (COCs) were obtained from local abattoir. After aspiration, the COCs were allotted into four treatments to evaluation of brilliant cresyl blue (BCB) test. Control treatment (C): oocytes were cultured directly (without exposure to BCB) after recovery in in vitro production (IVP) process. Oocyte treatment (OBCB): immediately after aspiration, COCs were incubated in modified Dulbecco's phosphate-buffered saline (mDPBS) supplemented with 26?M of BCB for 90min and classified into two classes: oocytes with blue cytoplasm coloration (OBCB+: more competent oocytes) and oocytes without blue cytoplasm coloration (OBCB-: low competent oocytes). Directly after classification, the oocytes were maintained undisrupted in the IVP process. Zygote treatment (ZBCB): After oocyte collection, maturation and fertilization, zygotes were stained with BCB for 10min and categorized into three ways, according to whether they were highly stained (ZBCB++: low competent zygotes), moderately stained (ZBCB+: moderate competent zygotes) and unstained (ZBCB-: more competent zygotes). Directly after classification, the zygotes were maintained undisrupted in the culture process. Oocyte and zygote treatments (OBCB/ZBCB): COCs were stained with BCB after recovery and classified into two classes (OBCB+ and OBCB-). After fertilization, the zygotes produced from OBCB+ and OBCB- oocytes were further stained with BCB for 10min and categorized six ways (OBCB+/ZBCB++, OBCB+/ZBCB+, OBCB+/ZBCB-, OBCB-/ZBCB++, OBCB-/ZBCB+ and OBCB-/ZBCB-). Directly after classification, the zygotes were maintained undisrupted in the culture process. The selection rate produced from OBCB treatment (OBCB+; 54.3%) was greater (P<0.05) than ZBCB treatment (ZBCB-; 44.3%). In addition, the selection rate produced from double application (combination of oocyte and zygote selection) of BCB test (OBCB+/ZBCB-: 28.8%) was less (P<0.01) than single application of BCB test (ZBCB-: 44.3%or OBCB+: 54.3%). The percentage of blastocyst production from OBCB+ oocytes (35.7%) and ZBCB- zygotes (36.6%) were greater (P<0.05) than that from C oocytes (25.7%), OBCB- oocytes (16.5%), ZBCB++ (13.5%) and ZBCB+ zygotes (21.3%). However, there were no significant differences (P>0.05) in the percentages of blastocyst production between OBCB+ oocytes (35.7%) and ZBCB- zygotes (36.6%). The proportion of blastocyst production from double application of BCB test (OBCB+/ZBCB-: 48.0%) was greater (P<0.05) than that from single application of BCB test (OBCB+: 35.7% or ZBCB-: 36.6%). In conclusion, current results confirmed that combination of oocyte and zygote selection by BCB test enhanced the efficiency of selecting for high quality embryos, compared to the single BCB test. PMID:23228698

Mirshamsi, S M; Karamishabankareh, H; Ahmadi-Hamedani, M; Soltani, L; Hajarian, H; Abdolmohammadi, A R

2013-01-30

231

Optical horn antennas for efficiently transferring photons from a quantum emitter to a single-mode optical fiber.  

PubMed

We theoretically demonstrate highly efficient optical coupling between a single quantum emitter and a monomode optical fiber over remarkably broad spectral ranges by extending the concept of horn antenna to optics. The optical horn antenna directs the radiation from the emitter toward the optical fiber and efficiently phase-matches the photon emission with the fiber mode. Numerical results show that an optical horn antenna can funnel up to 85% of the radiation from a dipolar source within an emission cone semi-angle as small as 7 degrees (antenna directivity of 300). It is also shown that 50% of the emitted power from the dipolar source can be collected and coupled to an SMF-28 fiber mode over spectral ranges larger than 1000 nm, with a maximum energy transfer reaching 70 %. This approach may open new perspectives in quantum optics and sensing. PMID:23389160

Grosjean, T; Mivelle, M; Burr, G W; Baida, F I

2013-01-28

232

A single gold nanorod as a plasmon resonance energy transfer based nanosensor for high-sensitivity Cu(II) detection.  

PubMed

Plasmon resonance energy transfer (PRET) has been widely applied in the detection of bio-recognition, heavy metal ions and cellular reactions with high sensitivity, based on the overlap between the plasmon resonance scattering band of nanoparticles and the absorption band of the surface-modified chromophore molecules. Previous sensors based on PRET were all implemented on gold nanospheres with scattering light in the range of 530 to 600 nm. In this work, a PRET-based nanosensor was developed on a thiol-di(2-picolyl)amine-modified single gold nanorod for the detection of Cu(2+) ions in aqueous solution with high sensitivity and selectivity. Compared to nanospheres, gold nanorods with tunable and wide plasmon resonance bands from the near-infrared to the infrared region exhibit promising potential for development as sensing probes. PMID:25338009

Jing, Chao; Shi, Lei; Liu, Xiaoyuan; Long, Yi-Tao

2014-12-21

233

Biological construction of single-walled carbon nanotube electron transfer pathways in dye-sensitized solar cells.  

PubMed

We designed and mass-produced a versatile protein supramolecule that can be used to manufacture a highly efficient dye-sensitized solar cell (DSSC). Twelve single-walled carbon-nanotube (SWNT)-binding and titanium-mineralizing peptides were genetically integrated on a cage-shaped dodecamer protein (CDT1). A process involving simple mixing of highly conductive SWNTs with CDT1 followed by TiO2 biomineralization produces a high surface-area/weight TiO2 -(anatase)-coated intact SWNT nanocomposite under environmentally friendly conditions. A DSSC with a TiO2 photoelectrode containing 0.2?wt?% of the SWNT-TiO2 nanocomposite shows a current density improvement by 80% and a doubling of the photoelectric conversion efficiency. The SWNT-TiO2 nanocomposite transfers photon-generated electrons from dye molecules adsorbed on the TiO2 to the anode electrode swiftly. PMID:25111295

Inoue, Ippei; Watanabe, Kiyoshi; Yamauchi, Hirofumi; Ishikawa, Yasuaki; Yasueda, Hisashi; Uraoka, Yukiharu; Yamashita, Ichiro

2014-10-01

234

SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications  

SciTech Connect

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

Onar, Omer C [ORNL] [ORNL; Tang, Lixin [ORNL] [ORNL; Chinthavali, Madhu Sudhan [ORNL] [ORNL; Campbell, Steven L [ORNL] [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC] [JNJ-Miller PLC

2014-01-01

235

Platinum and Palladium transfer to milk, organs and tissues after a single oral administration to lactating goats.  

PubMed

Platinum (Pt) and Palladium (Pd) are massively used in catalytic converters, emitted with exhaust fumes and deposited on roadsides in particle sizes. If they are ingested by ruminants grazing in agricultural fields located along roads they may enter the food chain. The objective of this study is to assess the potential transfer of Pt (PtCl(2)) and Pd (PdCl(2)) towards milk, tissues (muscle) and organs (kidney, liver and mammary gland). Three lactating goats received orally a single dose of 200mg of Pd and 200mg of Pt at the beginning of the experiment. The milk was collected each day during eight days. On the eighth day, organs and tissues were sampled to analyse the metal concentrations by ICP-MS (quantification limit of 0.25ng/g for Pd and Pt, detection limit of 0.08ng/g). The experiment demonstrated a significant transfer of Pd and Pt to kidney. The detected concentration was, respectively, of 73.9ng/g DW and 268.5n/g DW (factor 22 and factor 73 compared to the control kidney). The amounts of metals were : in the liver,18.1ng/g DW for the Pd and 8.1ng/g DW for the Pt, in the mammary gland, 14.9ng/g DW fort the Pd and 2.5ng/g DW for the Pt and in the muscle, 4.9ng/g DW for the Pd and 0.6ng/g DW for the Pt. The Pd concentration detected in milk was higher (from 5ng/g DW to 9ng/g DW) than in control milk but the transfer factor remained very low (0.02%). The Pt in milk could not be detected because it was below the quantification limit (<0.25ng/g DW). PMID:17336367

Ducoulombier-Crépineau, Cécile; Feidt, Cyril; Rychen, Guido

2007-06-01

236

Phase transfer catalysts drive diverse organic solvent solubility of single-walled carbon nanotubes helically wrapped by ionic, semiconducting polymers.  

PubMed

Use of phase transfer catalysts such as 18-crown-6 enables ionic, linear conjugated poly[2,6-{1,5-bis(3-propoxysulfonicacidsodiumsalt)}naphthylene]ethynylene (PNES) to efficiently disperse single-walled carbon nanotubes (SWNTs) in multiple organic solvents under standard ultrasonication methods. Steady-state electronic absorption spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) reveal that these SWNT suspensions are composed almost exclusively of individualized tubes. High-resolution TEM and AFM data show that the interaction of PNES with SWNTs in both protic and aprotic organic solvents provides a self-assembled superstructure in which a PNES monolayer helically wraps the nanotube surface with periodic and constant morphology (observed helical pitch length = 10 ± 2 nm); time-dependent examination of these suspensions indicates that these structures persist in solution over periods that span at least several months. Pump-probe transient absorption spectroscopy reveals that the excited state lifetimes and exciton binding energies of these well-defined nanotube-semiconducting polymer hybrid structures remain unchanged relative to analogous benchmark data acquired previously for standard sodium dodecylsulfate (SDS)-SWNT suspensions, regardless of solvent. These results demonstrate that the use of phase transfer catalysts with ionic semiconducting polymers that helically wrap SWNTs provide well-defined structures that solubulize SWNTs in a wide range of organic solvents while preserving critical nanotube semiconducting and conducting properties. PMID:20809609

Deria, Pravas; Sinks, Louise E; Park, Tae-Hong; Tomezsko, Diana M; Brukman, Matthew J; Bonnell, Dawn A; Therien, Michael J

2010-10-13

237

Large-Eddy Simulation of Heat Transfer from a Single Cube Mounted on a Very Rough Wall  

NASA Astrophysics Data System (ADS)

The local thermal effects in the wake of a single cube with a strong heated rear face, representing a large building in an urban area, are studied using large-eddy simulations (LES) for various degrees of heating, which are characterized by the local Richardson number, Ri. New wall models are implemented for momentum and temperature and comparison of the flow and thermal fields with the wind-tunnel data of Richards et al. (J Wind Eng Ind Aerodyn 94, 621-636, 2006) shows fair agreement. Buoyancy effects are quite evident at low Ri and a significant increase in the turbulence levels is observed for such flows. Apart from the comparisons with experiments, further analysis included the estimation of the thermal boundary-layer thickness and heat transfer coefficient for all Ri. For sufficiently strong heating, the heat transfer coefficient at the leeward face is found to be higher than the roof surface. This suggests that, beyond a certain Ri value, buoyancy forces from the former surface dominate the strong streamwise convection of the latter. Quadrant analysis along the shear layer behind the cube showed that the strength of sweeps that contribute to momentum flux is considerably enhanced by heating. The contribution of different quadrants to the heat flux is found to be very different to that of the momentum flux for lower Ri.

Boppana, V. B. L.; Xie, Zheng-Tong; Castro, Ian P.

2013-06-01

238

Kinetic analysis of electron transfer across single water-microdroplet/oil and oil-microdroplet/water interfaces.  

PubMed

Using techniques comprising laser trapping, microcapillary injection/manipulation, fluorescence microspectroscopy and electrochemistry of single microdroplets, we kinetically investigated the electron transfer (ET) reaction between decamethylferrocene in tributyl phosphate and hexacyanoferrate(III) in water. In the oil-microdroplet/water system, the overall ET reaction rate significantly depended on the droplet radius (r(d), 0.5 microm < r(d) < 10 microm) and on the potential-determining ion concentration in the oil phase. The interfacial ET reaction rate constant determined in the water-microdroplet (r(d) = 21 microm)/oil system agreed very well with that in the oil-microdroplet (r(d) > 2 microm)/water system. The rate constant values were extremely small in the Gibbs free energy (DeltaG) range of -10 to -25 kJ mol(-1), with DeltaG consisting of the Galvani potential difference between the water and oil phases and the redox potential difference of the solutes. The characteristic ET reaction was discussed in terms of the ion transfer and the ET across the interfacial mixed layer with nanometer-sized thickness. PMID:19212051

Nakatani, Kiyoharu; Uchino, Mitsuharu; Suzuki, Shingo; Negishi, Takayuki; Osakai, Toshiyuki

2009-02-01

239

Heat transfer and oil flow studies on a single-stage-to-orbit control-configured winged entry vehicle  

NASA Technical Reports Server (NTRS)

Results are presented for oil flow and phase change paint heat transfer tests conducted on a 0.006 scale model of a proposed single stage to orbit control configured vehicle. The data were taken at angles of attack up to 40 deg at a free stream Mach number of 10 for Reynolds numbers based on model length of 0.5 x 10 to the 6th power, 1.0 x 10 to the 6th power and 2.0 x 10 to the 6th power. The magnitude and distribution of heating are characterized in terms of angle of attack and Reynolds number aided by an analysis of the flow data which are used to suggest the presence of various three dimensional flow structures that produce the observed heating patterns. Of particular interest are streak heating patterns that result in high localized heat transfer rates on the wing windward surface at low to moderate angles of attack. These streaks are caused by the bow-shock/wing-shock interaction and formation of the wing-shock. Embedded vorticity was found to be associated with these interactions.

Helms, V. T., III; Bradley, P. F.

1984-01-01

240

Experimental and theoretical studies of the He(2+)-He system - Differential cross sections for direct, single-, and double-charge-transfer scattering at keV energies  

NASA Technical Reports Server (NTRS)

Measurements and calculations of differential cross sections for direct scattering, single-charge transfer, and double-charge transfer in collisions of 1.5-, 2.0-, 6.0-, and 10.0-keV (He-3)2+ with an He-4 target are reported. The measurements cover laboratory scattering angles below 1.5 deg with an angular resolution of about 0.03 deg. A quantum-mechanical molecular-state representation is employed in the calculations; in the case of single-charge transfer a two-state close-coupling calculation is carried out taking into account electron-translation effects. The theoretical calculations agree well with the experimental results for direct scattering and double-charge transfer. The present calculation identifies the origins of oscillatory structures observed in the differential cross sections.

Gao, R. S.; Dutta, C. M.; Lane, N. F.; Smith, K. A.; Stebbings, R. F.; Kimura, M.

1992-01-01

241

Charge transfer over localized states in a TlS single crystal  

NASA Astrophysics Data System (ADS)

It is revealed that TlS single crystals exhibit a variable range hopping conduction along a normal to their natural layers at temperatures T ? 230 K in a dc electric field and a nonactivated hopping conduction at low temperatures in strong electric fields. Estimates are made for the density of states near the Fermi level ( N F = 2.8 × 1020 eV-1 cm-3 and their energy spread (? W = 0.02 eV), the localization radius ( a = 33 Å), the average jump distance in the region of activated ( R av( T) = 40 Å) and nonactivated ( R av( F) = 78 Å) hopping conduction, and also the drop in the charge carrier potential energy along the jump distance in an electric field F: eFR = 0.006 and 0.009 eV at F = 7.50 × 103 and 1.25 × 104 V/cm, respectively.

Mustafaeva, S. N.; Asadov, M. M.; Ismailov, A. A.

2008-11-01

242

In situ superexchange electron transfer through a single molecule: A rectifying effect  

PubMed Central

An increasingly comprehensive body of literature is being devoted to single-molecule bridge-mediated electronic nanojunctions, prompted by their prospective applications in molecular electronics and single-molecule analysis. These junctions may operate in gas phase or electrolyte solution (in situ). For biomolecules, the latter is much closer to their native environment. Convenient target molecules are aromatic molecules, peptides, oligonucleotides, transition metal complexes, and, broadly, molecules with repetitive units, for which the conducting orbitals are energetically well below electronic levels of the solvent. A key feature for these junctions is rectification in the current–voltage relation. A common view is that asymmetric molecules or asymmetric links to the electrodes are needed to acquire rectification. However, as we show here, this requirement could be different in situ, where a structurally symmetric system can provide rectification because of the Debye screening of the electric field in the nanogap if the screening length is smaller than the bridge length. The Galvani potentials of each electrode can be varied independently and lead to a transistor effect. We explore this behavior for the superexchange mechanism of electron transport, appropriate for a wide class of molecules. We also include the effect of conformational fluctuations on the lowest unoccupied molecular orbital (LUMO) energy levels; that gives rise to non-Arrhenius temperature dependence of the conductance, affected by the molecule length. Our study offers an analytical formula for the current–voltage characteristics that demonstrates all these features. A detailed physical interpretation of the results is given with a discussion of reported experimental data. PMID:16641101

Kornyshev, Alexei A.; Kuznetsov, Alexander M.; Ulstrup, Jens

2006-01-01

243

Day 3 versus day 5 embryo transfer: a prospective randomized study.  

PubMed

Transfer of embryos at the blastocyst stage has been associated with exceptionally high implantation rates. There are, however, only a few prospective randomized studies comparing day 3 versus day 5 embryo transfer. Furthermore, the number of embryos replaced in the day 3 group transfer is often higher than the number of blastocysts replaced, thereby affecting implantation rates. A total of 118 patients undergoing standard IVF/intracytoplasmic sperm injection who had developed at least three 8-cell embryos showing <20% extracellular fragmentation on day 3 were randomized for day 3 or day 5 transfer. A maximum of two embryos were replaced. In this prospective, randomized study the implantation and pregnancy potential of embryos transferred on day 3 or day 5 were compared. Equal numbers of embryos were replaced in the two groups. There was no statistically significant difference between day 3 and day 5 transfer regarding positive human chorionic gonadotrophin rates (70 versus 67%), clinical pregnancy rates (61 versus 51%), implantation rates (44 versus 37%), twinning rates (42 versus 41%) and rates of early pregnancy loss (15 versus 29%). Transfer of embryos on day 3 or 5 showed similar implantation rates when equal numbers of embryos were transferred. Embryo transfer at the blastocyst stage seems to have no advantage over day 3 transfer in patients with more than two 8-cell embryos showing less than 20% fragmentation on day 3. PMID:12930586

Bungum, M; Bungum, L; Humaidan, P; Yding Andersen, C

2003-01-01

244

Melatonin Improves the Quality of In Vitro Produced (IVP) Bovine Embryos: Implications for Blastocyst Development, Cryotolerance, and Modifications of Relevant Gene Expression  

PubMed Central

To evaluate the potential effects of melatonin on the kinetics of embryo development and quality of blastocyst during the process of in vitro bovine embryo culture. Bovine cumulus–oocyte complexes (COCs) were fertilized after in vitro maturation. The presumed zygotes were cultured in in vitro culture medium supplemented with or without 10?7 M melatonin. The cleavage rate, 8-cell rate and blastocyst rate were examined to identify the kinetics of embryo development. The hatched blastocyst rate, mortality rate after thawing and the relevant transcript abundance were measured to evaluate the quality of blastocyst. The results showed that melatonin significantly promoted the cleavage rate and 8-cell embryo yield of in vitro produced bovine embryo. In addition, significantly more blastocysts were observed by Day 7 of embryo culture at the presence of melatonin. These results indicated that melatonin accelerated the development of in vitro produced bovine embryos. Following vitrification at Day 7 of embryo culture, melatonin (10?7 M) significantly increased the hatched blastocyst rate from 24 h to 72 h and decreased the mortality rate from 48 h to 72 h after thawing. The presence of melatonin during the embryo culture resulted in a significant increase in the gene expressions of DNMT3A, OCC, CDH1 and decrease in that of AQP3 after thawing. In conclusion, melatonin not only promoted blastocyst yield and accelerated in vitro bovine embryo development, but also improved the quality of blastocysts which was indexed by an elevated cryotolerance and the up-regulated expressions of developmentally important genes. PMID:24695534

Wang, Feng; Tian, XiuZhi; Zhou, YanHua; Tan, DunXian; Zhu, ShiEn; Dai, YunPing; Liu, GuoShi

2014-01-01

245

Communication: Adjusting charge transfer state energies for configuration interaction singles: without any parameterization and with minimal cost.  

PubMed

In a recent article, we showed that configuration interaction singles (CIS) has a systematic bias against charge-transfer (CT) states: CT vertical excitation energies are consistently too high (by 1-2 eV) as compared with non-CT energies [J. E. Subotnik, J. Chem. Phys. 137, 071104 (2011)]. We now show that this CIS error can be corrected approximately by performing a single Newton-Raphson step to reoptimize orbitals, thus establishing a new set of orbitals which better balances ground and excited state energies. The computational cost of this correction is exactly that of one coupled-perturbed Hartree-Fock calculation, which is effectively the cost of the CIS calculation itself. In other words, for twice the computational cost of a standard CIS calculation, or roughly the same cost as a linear-response time-dependent Hartree-Fock calculation, one can achieve a balanced, size-consistent description of CT versus non-CT energies, ideally with the accuracy of a much more expensive doubles CIS(D) calculation. PMID:22559462

Liu, Xinle; Fatehi, Shervin; Shao, Yihan; Veldkamp, Brad S; Subotnik, Joseph E

2012-04-28

246

Characterization of a novel embryonic stem cell line from an ICSI-derived blastocyst in the African green monkey.  

PubMed

Several cell types from the African green monkey (Cercopithecus aethiops), such as red blood cells, primary culture cells from kidney, and the Vero cell line, are valuable sources for biomedical research and testing. Embryonic stem (ES) cells that are established from blastocysts have pluripotency to differentiate into these and other types of cells. We examined an in vitro culture system of zygotes produced by ICSI in African green monkeys and attempted to establish ES cells. Culturing with and without a mouse embryonic fibroblast (MEF) cell monolayer resulted in the development of ICSI-derived zygotes to the blastocyst stage, while culturing with a buffalo rat liver cell monolayer yielded no development (3/14, 21.4% and 6/31, 19.4% vs 0/23, 0% respectively; P<0.05). One of the nine blastocysts, which had been one of the zygotes co-cultured with MEF cells, formed flat colonies consisting of cells with large nuclei, similar to other primate ES cell lines. The African green monkey ES (AgMES) cells expressed pluripotency markers, formed teratomas consisting of three embryonic germ layer tissues, and had a normal chromosome number. Furthermore, expression of the germ cell markers CD9 and DPPA3 (STELLA) was detected in the embryoid bodies, suggesting that AgMES cells might have the potential ability to differentiate into germ cells. The results suggested that MEF cells greatly affected the quality of the inner cell mass of the blastocysts. In addition, AgMES cells would be a precious resource for biomedical research such as other primate ES cell lines. PMID:19955206

Shimozawa, Nobuhiro; Nakamura, Shinichiro; Takahashi, Ichiro; Hatori, Masanori; Sankai, Tadashi

2010-03-01

247

Trophoblast adhesion of the peri-implantation mouse blastocyst is regulated by integrin signaling that targets phospholipase C  

Microsoft Academic Search

Integrin signaling modulates trophoblast adhesion to extracellular matrices during blastocyst implantation. Fibronectin (FN)-binding activity on the apical surface of trophoblast cells is strengthened after elevation of intracellular Ca2+ downstream of integrin ligation by FN. We report here that phosphoinositide-specific phospholipase C (PLC) mediates Ca2+ signaling in response to FN. Pharmacological agents used to antagonize PLC (U73122) or the inositol phosphate

Jun Wang; Linda Mayernik; D. Randall Armant

2007-01-01

248

Maternal-zygotic knockout reveals a critical role of Cdx2 in the morula to blastocyst transition  

PubMed Central

The first lineage segregation in the mouse embryo generates the inner cell mass (ICM), which gives rise to the pluripotent epiblast and therefore the future embryo, and the trophectoderm (TE), which will build the placenta. The TE lineage depends on the transcription factor Cdx2. However, when Cdx2 first starts to act remains unclear. Embryos with zygotic deletion of Cdx2 develop normally until the late blastocyst stage leading to the conclusion that Cdx2 is important for the maintenance but not specification of the TE. In contrast, down-regulation of Cdx2 transcripts from the early embryo stage results in defects in TE specification before the blastocyst stage. Here, to unambiguously address at which developmental stage Cdx2 becomes first required, we genetically deleted Cdx2 from the oocyte stage using a Zp3-Cre/loxP strategy. Careful assessment of a large cohort of Cdx2 maternal-zygotic null embryos, all individually filmed, examined and genotyped, reveals an earlier lethal phenotype than observed in Cdx2 zygotic null embryos that develop until the late blastocyst stage. The developmental failure of Cdx2 maternal-zygotic null embryos is associated with cell death and failure of TE specification, starting at the morula stage. These results indicate that Cdx2 is important for the correct specification of TE from the morula stage onwards and that both maternal and zygotic pools of Cdx2 are required for correct pre-implantation embryogenesis. PMID:25512302

Jedrusik, Agnieszka; Cox, Andy; Wicher, Krzysztof; Glover, David M.; Zernicka-Goetz, Magdalena

2015-01-01

249

Maternal-zygotic knockout reveals a critical role of Cdx2 in the morula to blastocyst transition.  

PubMed

The first lineage segregation in the mouse embryo generates the inner cell mass (ICM), which gives rise to the pluripotent epiblast and therefore the future embryo, and the trophectoderm (TE), which will build the placenta. The TE lineage depends on the transcription factor Cdx2. However, when Cdx2 first starts to act remains unclear. Embryos with zygotic deletion of Cdx2 develop normally until the late blastocyst stage leading to the conclusion that Cdx2 is important for the maintenance but not specification of the TE. In contrast, down-regulation of Cdx2 transcripts from the early embryo stage results in defects in TE specification before the blastocyst stage. Here, to unambiguously address at which developmental stage Cdx2 becomes first required, we genetically deleted Cdx2 from the oocyte stage using a Zp3-Cre/loxP strategy. Careful assessment of a large cohort of Cdx2 maternal-zygotic null embryos, all individually filmed, examined and genotyped, reveals an earlier lethal phenotype than observed in Cdx2 zygotic null embryos that develop until the late blastocyst stage. The developmental failure of Cdx2 maternal-zygotic null embryos is associated with cell death and failure of TE specification, starting at the morula stage. These results indicate that Cdx2 is important for the correct specification of TE from the morula stage onwards and that both maternal and zygotic pools of Cdx2 are required for correct pre-implantation embryogenesis. PMID:25512302

Jedrusik, Agnieszka; Cox, Andy; Wicher, Krzysztof; Glover, David M; Zernicka-Goetz, Magdalena

2015-02-15

250

Induction of arylhydrocarbon receptor expression in embryoblast cells of rabbit preimplantation blastocysts upon degeneration of Rauber's polar trophoblast.  

PubMed

The arylhydrocarbon receptor (AhR) is a ligand-activated transcription factor and mediates carcinogenic, teratogenic, and toxic effects of xenobiotics such as dioxin and coplanar polychlorinated biphenyls. The AhR nuclear translocator (ARNT) is involved in AhR signal transduction. We have analyzed the expression of AhR and ARNT mRNA and AhR protein in Day 3 pc (postcoitum) rabbit morulae and Days 4 and 6 pc blastocysts using RT-PCR, nested PCR, whole mount in situ hybridization, and whole mount immunohistochemistry with subsequent confocal laser scanning analysis. AhR and ARNT transcripts were detected in all stages investigated, indicating coexpression of both transcription factors. AhR protein was localized in the cytoplasm. It was detected in Day 3 pc morulae and in blastocysts. In Day 4 pc blastocysts, only trophoblast cells but not embryoblast cells were immunopositive. However, at Day 6 pc, the embryoblast cells also expressed AhR protein and this expression was correlated with the degeneration of Rauber's trophoblast layer. PMID:10366545

Tscheudschilsuren, G; Küchenhoff, A; Klonisch, T; Tetens, F; Fischer, B

1999-06-01

251

Osteopontin Is Expressed in the Mouse Uterus during Early Pregnancy and Promotes Mouse Blastocyst Attachment and Invasion In Vitro  

PubMed Central

Embryo implantation into the maternal uterus is a decisive step for successful mammalian pregnancy. Osteopontin (OPN) is a member of the small integrin-binding ligand N-linked glycoprotein family and participates in cell adhesion and invasion. In this study, we showed that Opn mRNA levels are up-regulated in the mouse uterus on day 4 and at the implantation sites on days 5 and 8 of pregnancy. Immunohistochemistry localized the OPN protein to the glandular epithelium on day 4 and to the decidual zone on day 8 of pregnancy. OPN mRNA and proteins are induced by in vivo and in vitro decidualization. OPN expression in the endometrial stromal cells is regulated by progesterone, a key regulator during decidualization. As a secreted protein, the protein level of OPN in the uterine cavity is enriched on day 4, and in vitro embryo culturing has indicated that OPN can facilitate blastocyst hatching and adhesion. Knockdown of OPN attenuates the adhesion and invasion of blastocysts in mouse endometrial stromal cells by suppressing the expression and enzymatic activity of matrix metalloproteinase-9 in the trophoblast. Our data indicated that OPN expression in the mouse uterus during early pregnancy is essential for blastocyst hatching and adhesion and that the knockdown of OPN in mouse endometrial stroma cells could lead to a restrained in vitro trophoblast invasion. PMID:25133541

Qi, Qian-Rong; Xie, Qing-Zhen; Liu, Xue-Li; Zhou, Yun

2014-01-01

252

Gene expression analysis of bovine blastocysts produced by parthenogenic activation or fertilisation.  

PubMed

The processes underlying the very first moments of embryonic development are still not well characterised in mammals. To better define the kinetics of events taking place following fertilisation, it would be best to have perfect synchronisation of sperm entry. With fertilisation occurring during a time interval of 6 to 12h in the same group of fertilised oocytes, this causes a major variation in the time of activation of embryonic development. Bovine parthenogenesis could potentially result in better synchronisation and, if so, would offer a better model for studying developmental competence. In the present study, bovine oocytes were either parthenogenetically activated or fertilised and cultured in vitro for 7 days. Gene expression analysis for those two groups of embryos at early and expanded stages was performed with BlueChip, a customised 2000-cDNA array developed in our laboratory and enriched in clones from various stages of bovine embryo development. The microarray data analysis revealed that only a few genes were differentially expressed, showing the relative similarity between those two kinds of embryos. Nevertheless, the fact that we obtained a similar diversity of developmental stages with parthenotes suggests that synchronisation is more oocyte-specific than sperm entry-time related. We then analysed our data with Ingenuity pathway analysis. Networks of genes involved in blastocyst implantation but also previous stages of embryo development, like maternal-to-embryonic transition, were identified. This new information allows us to better understand the regulatory mechanisms of embryonic development associated with embryo status. PMID:21557926

Labrecque, Rémi; Sirard, Marc-André

2011-01-01

253

Description of electron transfer in the ground and excited states of organic donor-acceptor systems by single-reference and multi-reference density functional methods  

NASA Astrophysics Data System (ADS)

Electron transfer in the ground and excited states of a model donor-acceptor (D-A) system is investigated using the single-reference and multi-reference density functional theory (DFT) methods. To analyze the results of the calculations, a simple two-site multi-reference model was derived that predicts a stepwise electron transfer in the S0 state and a wave-like dependence of the S1 electron transfer on the external stimulus. The standard single-reference Kohn-Sham (KS) DFT approach and the time-dependent DFT (TDDFT) method failed to describe the correct dependence of the S0 and S1 electron transfer on the external electric field applied along the donor-acceptor system. The multi-reference DFT approach, the spin-restricted ensemble-referenced KS (REKS) method, was able to successfully reproduce the correct behavior of the S0 and S1 electron transfer on the applied field. The REKS method was benchmarked against experimentally measured gas phase charge transfer excitations in a series of organic donor-acceptor complexes and displayed its ability to describe this type of electronic transitions with a very high accuracy, mean absolute error of 0.05 eV with the use of the standard range separated density functionals. On the basis of the calculations undertaken in this work, it is suggested that the non-adiabatic coupling between the S0 and S1 states may interfere with the electron transfer in a weakly coupled donor-acceptor system. It is also suggested that the electronic excitation of a D+-A- system may play a dual role by assisting the further electron transfer at certain magnitudes of the applied electric field and causing the backward transfer at lower electric field strengths.

Filatov, Michael

2014-09-01

254

The performance of single- and multi-proxy transfer functions (testate amoebae, bryophytes, vascular plants) for reconstructing mire surface wetness and pH  

NASA Astrophysics Data System (ADS)

Peatlands are widely exploited archives of paleoenvironmental change. We developed and compared multiple transfer functions to infer peatland depth to the water table (DWT) and pH based on testate amoeba (percentages, or presence/absence), bryophyte presence/absence, and vascular plant presence/absence data from sub-alpine peatlands in the SE Swiss Alps in order to 1) compare the performance of single-proxy vs. multi-proxy models and 2) assess the performance of presence/absence models. Bootstrapping cross-validation showing the best performing single-proxy transfer functions for both DWT and pH were those based on bryophytes. The best performing transfer functions overall for DWT were those based on combined testate amoebae percentages, bryophytes and vascular plants; and, for pH, those based on testate amoebae and bryophytes. The comparison of DWT and pH inferred from testate amoeba percentages and presence/absence data showed similar general patterns but differences in the magnitude and timing of some shifts. These results show new directions for paleoenvironmental research, 1) suggesting that it is possible to build good-performing transfer functions using presence/absence data, although with some loss of accuracy, and 2) supporting the idea that multi-proxy inference models may improve paleoecological reconstruction. The performance of multi-proxy and single-proxy transfer functions should be further compared in paleoecological data.

Mitchell, Edward A. D.; Payne, Richard J.; van der Knaap, Willem O.; Lamentowicz, ?ukasz; G?bka, Maciej; Lamentowicz, Mariusz

2013-01-01

255

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?  

33 ? Navigation and Navigable Waters ? 2 ? 2014-07-01 ? 2014-07-01 ? false ? When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water? ? 150.445 ? Section 150.445 ? Navigation and Navigable Waters ? COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ?...

2014-07-01

256

A Newton-Raphson method for calculating condenser performance based on ASME single tube heat transfer data  

SciTech Connect

The calculation of condenser performance should include the response of the LP stage of the turbo-generator. The set of operating conditions for this subsystem, given a set of boundary conditions (e.g. MW load, cooling water inlet temperature and/or flow rate), recognizes the simultaneous presence of three heat transport mechanisms. Under steady state conditions, (1) the latent heat to be removed from the vapor equals; (2) the amount of heat transferred through the thermal resistances consisting of the tube walls and film boundary layers; and this must also equal; and (3) the amount of heat acquired by the cooling water. This set of simultaneous equations is non-linear and is most readily solved by using the Newton-Raphson algorithm. With fossil plants the objective is to calculate the change in condenser duty due to fouling, given the present generated load. However, with nuclear plants the change in condenser duty now reflects a certain amount of generated power which has had to be foregone. In both cases, a reduction in condenser duty translates into a reduction in unit heat rate. With both types of plant there are a number of condenser configurations, including single compartment condensers with either single or double passes; and multi-compartment condensers, often with each compartment operating at a different pressure. Clearly, the equation set must be adjusted to take these variations into account. The attractiveness of the Newton-Raphson approach is that accurate loss estimates for any configuration can be achieved by merely modifying the set of variables and equations involved in the calculations, and adjusting the associated set of input/output data displays to suit. In this way the same basic software structure can be used to solve this whole family of problems. 12 refs., 4 figs., 8 tabs.

Putman, R.E.; Saxon, G.E. Jr. [Conco Consulting Corp., Verona, PA (United States)

1996-08-01

257

A newton-Raphson method for calculating condenser performance based on the ASME single tube heat transfer data  

SciTech Connect

The calculation of condenser performance should include the response of the LP stage of the turbo-generator. The set of operating conditions for this subsystem, given a set of boundary conditions (e.g. MW load, cooling water inlet temperature and/or flow rate), recognizes the simultaneous presence of three heat transport mechanisms. Under steady state conditions, (1) the latent heat to be removed from the vapor equals (2) the amount of heat transferred through the thermal resistances consisting of the tube walls and film boundary layers; and this must also equal (3) the amount of heat acquired by the cooling water. This set of simultaneous equations is non-linear and is most readily solved by using the Newton-Raphson algorithm. With fossil plants the objective is to calculate the change in condenser duty due to fouling, given the present generated load. However, with nuclear plants the change in condenser duty now reflects a certain amount of generated power which has had to be foregone. In both cases, a reduction in condenser duty translates into a reduction in unit heat rate. With both types of plant there are a number of condenser configurations, including single compartment condensers with either single or double passes; and multi-compartment condensers, often with each compartment operating at a different pressure. Clearly, the equation set must be adjusted to take these variations into account. The attractiveness of the Newton-Raphson approach is that accurate loss estimates for any configuration can be achieved by merely modifying the set of variables and equations involved in the calculations, and adjusting the associated set of input/output data displays to suit. In this way the same basic software structure can be used to solve this whole family of problems.

Putman, R.E.; Saxon, G.E. Jr. [Conco Consulting Corp., Verona, PA (United States)

1996-05-01

258

Studies of single- and two-phase heat transfer in a blocked four-rod bundle. Final report. [PWR  

Microsoft Academic Search

Correlations have been developed for the heat transfer coefficient in the vicinity of flow blockages in rod bundles. The heat transfer data have been obtained on a four rod bundle with sleeve-type blockages for a Reynolds number range of 230 to 6900 and void fractions up to 0.15. Significant enhancement of the heat transfer coefficient has been observed downstream of

M. Drucker; V. K. Dhir

1984-01-01

259

Structural variability of nucleosomes detected by single-pair Förster resonance energy transfer: histone acetylation, sequence variation, and salt effects.  

PubMed

Nucleosomes were reconstituted from 170 bp long fragments of 5S rDNA and an optimal positioning sequence, the Selex 601, with recombinant histones. In free-solution single pair Förster resonance energy transfer (spFRET) measurements of the distance between fluorescently labeled bases in the nucleosomal DNA, the samples exhibited structural diversity. The structural heterogeneity correlated with the stability of the complexes and depended on the DNA sequence and histone acetylation. The stability of the nucleosomes was assessed via dilution-driven disruption: histone acetylation decreased nucleosome stability. The spFRET experiments used a new approach for data acquisition and analysis that we term "deliberately detuned detection" (D3). This permits the separation of subpopulations in the samples even for the low-FRET regime characteristic for the linker-DNA labeled nucleosomes. Thus, it became possible to study in more detail histone acetylation- and salt-dependent structural variations using either end- or internally labeled DNAs on the nucleosome. We found that the distance distribution of the fluorophore pairs on the linker DNA ends was much more sensitive to histone acetylation or sequence variation than that of labels on the internal part of the DNA, which was more tightly associated with the histone core. spFRET on freely diffusing nucleosomes allows us therefore to localize the influence of histone modifications and DNA sequence variations on the nucleosome structure and dynamics. PMID:18950220

Gansen, Alex; Tóth, Katalin; Schwarz, Nathalie; Langowski, Jörg

2009-03-01

260

Electron-transfer sensitization of H2 oxidation and CO2 reduction catalysts using a single chromophore.  

PubMed

Energy-storing artificial-photosynthetic systems for CO2 reduction must derive the reducing equivalents from a renewable source rather than from sacrificial donors. To this end, a homogeneous, integrated chromophore/two-catalyst system is described that is thermodynamically capable of photochemically driving the energy-storing reverse water-gas shift reaction (CO2 + H2 ? CO + H2O), where the reducing equivalents are provided by renewable H2. The system consists of the chromophore zinc tetraphenylporphyrin (ZnTPP), H2 oxidation catalysts of the form [Cp(R)Cr(CO)3](-), and CO2 reduction catalysts of the type Re(bpy-4,4'-R2)(CO)3Cl. Using time-resolved spectroscopic methods, a comprehensive mechanistic and kinetic picture of the photoinitiated reactions of mixtures of these compounds has been developed. It has been found that absorption of a single photon by broadly absorbing ZnTPP sensitizes intercatalyst electron transfer to produce the substrate-active forms of each. The initial photochemical step is the heretofore unobserved reductive quenching of the low-energy T1 state of ZnTPP. Under the experimental conditions, the catalytically competent state decays with a second-order half-life of ?15 ?s, which is of the right magnitude for substrate trapping of sensitized catalyst intermediates. PMID:24961370

La Porte, Nathan T; Moravec, Davis B; Hopkins, Michael D

2014-07-01

261

Calibration of ? single hexagonal NaI(Tl) detector using a new numerical method based on the efficiency transfer method  

NASA Astrophysics Data System (ADS)

Gamma-ray detector systems are important instruments in a broad range of science and new setup are continually developing. The most recent step in the evolution of detectors for nuclear spectroscopy is the construction of large arrays of detectors of different forms (for example, conical, pentagonal, hexagonal, etc.) and sizes, where the performance and the efficiency can be increased. In this work, a new direct numerical method (NAM), in an integral form and based on the efficiency transfer (ET) method, is used to calculate the full-energy peak efficiency of a single hexagonal NaI(Tl) detector. The algorithms and the calculations of the effective solid angle ratios for a point (isotropic irradiating) gamma-source situated coaxially at different distances from the detector front-end surface, taking into account the attenuation of the gamma-rays in the detector's material, end-cap and the other materials in-between the gamma-source and the detector, are considered as the core of this (ET) method. The calculated full-energy peak efficiency values by the (NAM) are found to be in a good agreement with the measured experimental data.

Abbas, Mahmoud I.; Badawi, M. S.; Ruskov, I. N.; El-Khatib, A. M.; Grozdanov, D. N.; Thabet, A. A.; Kopatch, Yu. N.; Gouda, M. M.; Skoy, V. R.

2015-01-01

262

Poly(N-isopropylacrylamide) brushes grafted from cellulose nanocrystals via surface-initiated single-electron transfer living radical polymerization.  

PubMed

Cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with thermoresponsive macromolecules. The CNCs were grafted with poly(N-isopropylacrylamide) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SET-LRP) under various conditions at room temperature. The grafting process was confirmed via Fourier transform IR spectroscopy and X-ray photoelectron spectroscopy and the different molecular masses of the grafts were quantified and found to depend on the initiator and monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. It is expected that suspension stability, interfacial interactions, friction, and other properties of grafted CNCs can be controlled by changes in temperature and provide a unique platform for further development of stimuli-responsive nanomaterials. PMID:20843063

Zoppe, Justin O; Habibi, Youssef; Rojas, Orlando J; Venditti, Richard A; Johansson, Leena-Sisko; Efimenko, Kirill; Osterberg, Monika; Laine, Janne

2010-10-11

263

Expression of the Alpha Tocopherol Transfer Protein gene is regulated by Oxidative Stress and Common Single Nucleotide Polymorphisms  

PubMed Central

Vitamin E (?-tocopherol) is the major lipid soluble antioxidant in most animal species. By controlling the secretion of vitamin E from the liver, the ?-tocopherol transfer protein (?TTP) regulates whole-body distribution and levels of this vital nutrient. However, the mechanism(s) that regulate the expression of this protein are poorly understood. Here we report that transcription of the TTPA gene in immortalized human hepatocytes (IHH) is induced by oxidative stress and by hypoxia, by agonists of the nuclear receptors PPAR? and RXR, and by increased cAMP levels. The data show further that induction of TTPA transcription by oxidative stress is mediated by an already-present transcription factor, and does not require de novo protein synthesis. Silencing of the cAMP response element binding (CREB) transcription factor attenuated transcriptional responses of the TTPA gene to added peroxide, suggesting that CREB mediates responses of this gene to oxidative stress. Using a 1.9 Kb proximal segment of the human TTPA promoter together with site-directed mutagenesis approach, we found that single nucleotide polymorphisms (SNPs) that are commonly found in healthy humans dramatically affect promoter activity. These observations suggest that oxidative stress and individual genetic makeup contribute to vitamin E homeostasis in humans. These findings may explain the variable responses to vitamin E supplementation observed in human clinical trials. PMID:23079030

Ulatowski, Lynn; Dreussi, Cara; Noy, Noa; Barnholtz-Sloan, Jill; Klein, Eric; Manor, Danny

2012-01-01

264

A homogeneous single-label quenching resonance energy transfer assay for a ?-opioid receptor-ligand using intact cells.  

PubMed

This study, a homogeneous assay system for delta opioid receptor binding ligands has been developed using Quenching Resonance Energy Transfer (QRET). The QRET system allows receptor-ligand binding assays on intact cells using a single-label approach and a nonspecific quenching mechanism. Binding of antagonists or agonists to the receptor can be defined using a europium(III) labeled ligand. In the presence of the unlabeled ligand the labeled ligand is displaced and remains in solution. The non-bound labeled ligand is not protected by the target receptor, and the luminescence signal is quenched. For this objective, a Eu(III) labeled peptide molecule with three different linkers (AX0, AX1 and AX2) was designed. Peptides were evaluated using the homogeneous QRET technique, radioligand binding assays and the heterogeneous time-resolved luminescence (TRL) technique. Using the Eu-AX0 peptide and the QRET method, a panel of opioid compounds (naltrexone, naltrindole, SCN-80, DPDPE and DAMGO) was tested to prove the assay performance. The signal-to-background ratio for the tested opioid ligand ranged from 3.3 to 12.0. The QRET method showed prominent performance also in high DMSO concentrations. QRET is a homogenous and a non-radioactive detection system for screening and this is the first attempt to utilize peptide ligands in the QRET concept. PMID:23800721

Kopra, Kari; Shweta; Martikkala, Eija; Hänninen, Pekka; Petäjä-Repo, Ulla; Härmä, Harri

2013-09-01

265

Charge transfer of single laser crystallized intrinsic and phosphorus-doped Si-nanocrystals visualized by Kelvin probe force microscopy  

NASA Astrophysics Data System (ADS)

Isolated intrinsic and phosphorus doped (P-doped) Si-nanocrystals (Si-NCs) on n- and p-Si substrates are fabricated by excimer laser crystallization techniques. The formation of Si-NCs is confirmed by atomic force microscopy (AFM) and conductive AFM measurements. Kelvin probe force microscopy (KPFM) is then carried out to visualize the trapped charges in a single Si-NC dot which derives from the charge transfer between Si-NCs and Si substrates due to their different Fermi levels. The laser crystallized P-doped Si-NCs have a similar Fermi level around the mid-gap to the intrinsic counterparts, which might be caused by the inactivated impurity atoms or the surface states-related Fermi level pinning. A clear rise of the Fermi level in P-doped Si-NCs is observed after a short time thermal annealing treatment, indicating the activation of dopants in Si-NCs. Moreover, the surface charge quantity can be estimated using a simple parallel plate capacitor model for a quantitative understanding of the KPFM results at the nanoscale.

Xu, Jie; Xu, Jun; Lu, Peng; Shan, Dan; Li, Wei; Chen, Kunji

2014-10-01

266

A high-yield two-step transfer printing method for large-scale fabrication of organic single-crystal devices on arbitrary substrates.  

PubMed

Single-crystal organic nanostructures show promising applications in flexible and stretchable electronics, while their applications are impeded by the large incompatibility with the well-developed photolithography techniques. Here we report a novel two-step transfer printing (TTP) method for the construction of organic nanowires (NWs) based devices onto arbitrary substrates. Copper phthalocyanine (CuPc) NWs are first transfer-printed from the growth substrate to the desired receiver substrate by contact-printing (CP) method, and then electrode arrays are transfer-printed onto the resulting receiver substrate by etching-assisted transfer printing (ETP) method. By utilizing a thin copper (Cu) layer as sacrificial layer, microelectrodes fabricated on it via photolithography could be readily transferred to diverse conventional or non-conventional substrates that are not easily accessible before with a high transfer yield of near 100%. The ETP method also exhibits an extremely high flexibility; various electrodes such as Au, Ti, and Al etc. can be transferred, and almost all types of organic devices, such as resistors, Schottky diodes, and field-effect transistors (FETs), can be constructed on planar or complex curvilinear substrates. Significantly, these devices can function properly and exhibit closed or even superior performance than the device counterparts fabricated by conventional approach. PMID:24942458

Deng, Wei; Zhang, Xiujuan; Pan, Huanhuan; Shang, Qixun; Wang, Jincheng; Zhang, Xiaohong; Zhang, Xiwei; Jie, Jiansheng

2014-01-01

267

A High-yield Two-step Transfer Printing Method for Large-scale Fabrication of Organic Single-crystal Devices on Arbitrary Substrates  

NASA Astrophysics Data System (ADS)

Single-crystal organic nanostructures show promising applications in flexible and stretchable electronics, while their applications are impeded by the large incompatibility with the well-developed photolithography techniques. Here we report a novel two-step transfer printing (TTP) method for the construction of organic nanowires (NWs) based devices onto arbitrary substrates. Copper phthalocyanine (CuPc) NWs are first transfer-printed from the growth substrate to the desired receiver substrate by contact-printing (CP) method, and then electrode arrays are transfer-printed onto the resulting receiver substrate by etching-assisted transfer printing (ETP) method. By utilizing a thin copper (Cu) layer as sacrificial layer, microelectrodes fabricated on it via photolithography could be readily transferred to diverse conventional or non-conventional substrates that are not easily accessible before with a high transfer yield of near 100%. The ETP method also exhibits an extremely high flexibility; various electrodes such as Au, Ti, and Al etc. can be transferred, and almost all types of organic devices, such as resistors, Schottky diodes, and field-effect transistors (FETs), can be constructed on planar or complex curvilinear substrates. Significantly, these devices can function properly and exhibit closed or even superior performance than the device counterparts fabricated by conventional approach.

Deng, Wei; Zhang, Xiujuan; Pan, Huanhuan; Shang, Qixun; Wang, Jincheng; Zhang, Xiaohong; Zhang, Xiwei; Jie, Jiansheng

2014-06-01

268

Heat-transfer resistance at solid-liquid interfaces: a tool for the detection of single-nucleotide polymorphisms in DNA.  

PubMed

In this article, we report on the heat-transfer resistance at interfaces as a novel, denaturation-based method to detect single-nucleotide polymorphisms in DNA. We observed that a molecular brush of double-stranded DNA grafted onto synthetic diamond surfaces does not notably affect the heat-transfer resistance at the solid-to-liquid interface. In contrast to this, molecular brushes of single-stranded DNA cause, surprisingly, a substantially higher heat-transfer resistance and behave like a thermally insulating layer. This effect can be utilized to identify ds-DNA melting temperatures via the switching from low- to high heat-transfer resistance. The melting temperatures identified with this method for different DNA duplexes (29 base pairs without and with built-in mutations) correlate nicely with data calculated by modeling. The method is fast, label-free (without the need for fluorescent or radioactive markers), allows for repetitive measurements, and can also be extended toward array formats. Reference measurements by confocal fluorescence microscopy and impedance spectroscopy confirm that the switching of heat-transfer resistance upon denaturation is indeed related to the thermal on-chip denaturation of DNA. PMID:22356595

van Grinsven, Bart; Vanden Bon, Natalie; Strauven, Hannelore; Grieten, Lars; Murib, Mohammed; Monroy, Kathia L Jiménez; Janssens, Stoffel D; Haenen, Ken; Schöning, Michael J; Vermeeren, Veronique; Ameloot, Marcel; Michiels, Luc; Thoelen, Ronald; De Ceuninck, Ward; Wagner, Patrick

2012-03-27

269

Lipid transfer between small unilamellar vesicles and single bilayers on a solid support: self-assembly of supported bilayers with asymmetric lipid distribution.  

PubMed

The transfer of lipids between small unilamellar vesicles of either dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidylglycerol (DMPG), or dioctadecyl diammonium bromide (DODAB) and a single bilayer on a solid support of chain perdeuterated DMPC-d54 has been studied by time-resolved ATR infrared spectroscopy, deuterium NMR, and DSC. The IR method was used for measuring the transfer kinetics and the amount of lipid transferred to the supported bilayer, while NMR was employed for the assessment of molecular order and for the occurrence of lipid asymmetries due to the transfer. We find that the composition of a supported planar dimyristoylphosphatidylcholine (DMPC-d54) bilayer can be modified by incubation with high concentrations of sonicated vesicles consisting of the donor lipid. Three cases were studied. First, the incubation was done with DMPC as donor lipid. The kinetics of this process is double exponential and comparatively slow, with a half-time in the range of several hours. The activation energy was estimated as 50 +/- 2 kJ/mol. In a second set of measurements, cationic DODAB or anionic DMPG was used as donor lipid. The kinetics of this transfer is 1 order of magnitude faster than for DMPC and can be described by a single exponential. For DMPG transfer, we obtained an activation energy of 35 +/- 2 kJ/mol. Independent of the headgroup charge of the donor lipid, 25-35% of the (acceptor) DMPC in the supported bilayer is not accessible for exchange with the donor lipid. The transfer of either DMPG or DODAB causes drastic changes of the phase transition behavior of the supported bilayer without significantly altering the lipid packing density of the lipids.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7947819

Reinl, H M; Bayerl, T M

1994-11-29

270

Oct4 is required for lineage priming in the developing inner cell mass of the mouse blastocyst  

PubMed Central

The transcription factor Oct4 is required in vitro for establishment and maintenance of embryonic stem cells and for reprogramming somatic cells to pluripotency. In vivo, it prevents the ectopic differentiation of early embryos into trophoblast. Here, we further explore the role of Oct4 in blastocyst formation and specification of epiblast versus primitive endoderm lineages using conditional genetic deletion. Experiments involving mouse embryos deficient for both maternal and zygotic Oct4 suggest that it is dispensable for zygote formation, early cleavage and activation of Nanog expression. Nanog protein is significantly elevated in the presumptive inner cell mass of Oct4 null embryos, suggesting an unexpected role for Oct4 in attenuating the level of Nanog, which might be significant for priming differentiation during epiblast maturation. Induced deletion of Oct4 during the morula to blastocyst transition disrupts the ability of inner cell mass cells to adopt lineage-specific identity and acquire the molecular profile characteristic of either epiblast or primitive endoderm. Sox17, a marker of primitive endoderm, is not detected following prolonged culture of such embryos, but can be rescued by provision of exogenous FGF4. Interestingly, functional primitive endoderm can be rescued in Oct4-deficient embryos in embryonic stem cell complementation assays, but only if the host embryos are at the pre-blastocyst stage. We conclude that cell fate decisions within the inner cell mass are dependent upon Oct4 and that Oct4 is not cell-autonomously required for the differentiation of primitive endoderm derivatives, as long as an appropriate developmental environment is established. PMID:24504341

Le Bin, Gloryn Chia; Muñoz-Descalzo, Silvia; Kurowski, Agata; Leitch, Harry; Lou, Xinghua; Mansfield, William; Etienne-Dumeau, Charles; Grabole, Nils; Mulas, Carla; Niwa, Hitoshi; Hadjantonakis, Anna-Katerina; Nichols, Jennifer

2014-01-01

271

Three-dimensional analysis of heat transfer in a micro-heat sink with single phase flow  

Microsoft Academic Search

A detailed numerical simulation of forced convection heat transfer occurring in silicon-based microchannel heat sinks has been conducted using a simplified three-dimensional conjugate heat transfer model (2D fluid flow and 3D heat transfer). The micro-heat sink model consists of a 10 mm long silicon substrate, with rectangular microchannels, 57 ?m wide and 180 ?m deep, fabricated along the entire length.

J. Li; G. P. Peterson; P. Cheng

2004-01-01

272

Chemiluminescence resonance energy transfer imaging on magnetic particles for single-nucleotide polymorphism detection based on ligation chain reaction.  

PubMed

A novel ligation chain reaction (LCR) methodology for single-nucleotide polymorphism (SNP) detection was developed based on luminol-H2O2-horseradish peroxidase (HRP)-mimicking DNAzyme-fluorescein chemiluminescence resonance energy transfer (CRET) imaging on magnetic particles. For LCR, four unique target-complement probes (X and X(?), YG and Y(?)) for the amplification of K-ras (G12C) were designed by modifying G-quadruplex sequence at 3'-end of YG and fluorescein at 5'-end of Y(?). After the LCR, the resulting products of XYG/X(?)Y(?) with biotin-labeled X(?) were captured onto streptavidin-coated magnetic particles (SA-MPs) via specific biotin-SA interaction, which stimulated the CRET reaction from hemin/G-quadruplex-catalyzed luminol-H2O2 CL system to fluorescein. By collecting signals by a cooled low-light CCD, a CRET imaging method was proposed for visual detection and quantitative analysis of SNP. As low as 0.86fM mutant DNA was detected by this assay, and positive mutation detection was achieved with a wild-type to mutant ratio of 10,000:1. This high sensitivity and specificity could be attributed to not only the exponential amplification and excellent discrimination of LCR but also the employment of SA-MPs. SA-MPs ensured the feasibility of the proposed strategy, which also simplified the operations through magnetic separation and separated the reaction and detection procedures to improve sensitivity. The proposed LCR-CRET imaging strategy extends the application of signal amplification techniques to SNP detection, providing a promising platform for effective and high-throughput genetic diagnosis. PMID:25461149

Bi, Sai; Zhang, Zhipeng; Dong, Ying; Wang, Zonghua

2014-10-17

273

Influence of heat and mass transfer on the ignition and NO x formation in single droplet combustion  

NASA Astrophysics Data System (ADS)

The effect of heat and mass transfer on the ignition, and in a second step on the nitrogen oxide (NO x ) generation, of single burning droplets is examined in a numerical study. Spherical symmetry with no gravity and no forced convection is presumed; ambient temperature is set at 500 K, below the auto-ignition point. The essentials of a forced droplet ignition by an external energy source are introduced. Two methods are applied: heat introduction at a fixed radial position r and heat introduction at a fixed local equivalence ratio ? r . This study's distinctiveness compared to previous research is its focus on and its combination of partially pre-vaporized droplets and detailed chemistry, both being technically relevant in kerosene and diesel fuel combustion. The fuel of choice is n-decane (C10H22), and NO x production is studied exemplarily as a representative group of pollutant emissions. The conducted simulations show a decrease of NO x formation with an increase of the pre-vaporization rate Uppsi. This decrease is generally valid for both methods of heat introduction. However, results on flame stabilization and NO x production reveal a high sensitivity to parameters of the ignition model. The burning behavior during the initial stages is dominated by the ignition position. Extracting heat from the exhaust gas region of burning droplets shows no impact on the flame position nor on the relative NO x production. As a consequence, a well-founded modeling of the investigated droplet regime needs to resort to an iterative adaptation of the heat introduction parameters based on the findings of droplet burning and exhaust gas production.

Moesl, Klaus G.; Schwing, Joachim E.; Fenninger, Wolfgang J.; Sattelmayer, Thomas

2011-08-01

274

Production, freezing and transfer of bovine IVF embryos and subsequent calving results  

Microsoft Academic Search

Ultrasound-guided oocyte aspirations were performed repeatedly, on a weekly basis, on 155 different cows. An average of 4.9 oocytes with 4.1 classified as usable were collected. Following in vitro maturation (IVM), fertilization (IVF) and culture (IVC), a few Day 7 morulae, and all Day 7 and most Day 8 blastocysts were either transferred or frozen. The transfer of 2268 fresh

J. F. Hasler; W. B. Henderson; P. J. Hurtgen; Z. Q. Jin; A. D. McCauley; S. A. Mower; B. Neely; L. S. Shuey; J. E. Stokes; S. A. Trimmer

1995-01-01

275

Experimental Analysis of the Single-Phase Heat Transfer and Friction Factor inside the Horizontal Internally Micro-Fin Tube  

E-print Network

of tube is widely used in high flow rate applications because the heat transfer enhancement in high flow rates (turbulent region) is more pronounced than that in the low flow rates (laminar region). Khanpara and shell-side condensers to increase heat transfer. This enables water chillers to reach high efficiency

Ghajar, Afshin J.

276

Statistics and kinetics of single-molecule electron transfer dynamics in complex environments: A simulation model study  

Microsoft Academic Search

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments

Luciana C. Paula; Jin Wang; Vitor B. P. Leite

2008-01-01

277

Response of blastocyst-endometrium interactions in albino rats to sublethal doses of biological and synthetic insecticides.  

PubMed

The present study compared morphological, histochemical and histomorphometric characteristics of the sublethal effects of XenTari® and deltamethrin in blastocyst-endometrium interactions in female rats. Pregnant rats received 185, 1850 and 3700mg of XenTari® or 1.0, 2.0 and 4.0mg of deltamethrin (all doses per kg of body weight) and were sacrificed on the seventh day of pregnancy. The rats treated with the higher doses of insecticides exhibited a significant reduction in the number of implantation sites, vacuolated trophoblast cells, rare cytotrophoblasts, accentuated leukocyte infiltration, increase in vascularization of sites and blood in the uterine lumen. The decidua was more fibrous, particularly in the rats treated with the highest dose of XenTari®. In conclusion, sublethal doses of both XenTari® and deltamethrin produced qualitative/quantitative alterations in the blastocyst-endometrium interaction in female rats, thereby compromising the implantation process. Further studies are needed particularly at verifying the effects of these insecticides in the pregnancy to term in rats, order to investigate possible correlated effects on women working or living near agricultural fields. PMID:21745526

Lemos, Ana Janaína Jeanine M; Wanderley-Teixeira, Valeria; Teixeira, Alvaro Aguiar C; Silva, Fernanda das Chagas A; Oliveira, José V; de Siqueira, Herbert Álvaro A

2011-10-01

278

Long term costs and effects of reducing the number of twin pregnancies in IVF by single embryo transfer: the TwinSing study  

PubMed Central

Background Pregnancies induced by in vitro fertilisation (IVF) often result in twin gestations, which are associated with both maternal and perinatal complications. An effective way to reduce the number of IVF twin pregnancies is to decrease the number of embryos transferred from two to one. The interpretation of current studies is limited because they used live birth as outcome measure and because they applied limited time horizons. So far, research on long-term outcomes of IVF twins and singletons is scarce and inconclusive. The objective of this study is to investigate the short (1-year) and long-term (5 and 18-year) costs and health outcomes of IVF singleton and twin children and to consider these in estimating the cost-effectiveness of single embryo transfer compared with double embryo transfer, from a societal and a healthcare perspective. Methods/Design A multi-centre cohort study will be performed, in which IVF singletons and IVF twin children born between 2003 and 2005 of whom parents received IVF treatment in one of the five participating Dutch IVF centres, will be compared. Data collection will focus on children at risk of health problems and children in whom health problems actually occurred. First year of life data will be collected in approximately 1,278 children (619 singletons and 659 twin children). Data up to the fifth year of life will be collected in approximately 488 children (200 singletons and 288 twin children). Outcome measures are health status, health-related quality of life and costs. Data will be obtained from hospital information systems, a parent questionnaire and existing registries. Furthermore, a prognostic model will be developed that reflects the short and long-term costs and health outcomes of IVF singleton and twin children. This model will be linked to a Markov model of the short-term cost-effectiveness of single embryo transfer strategies versus double embryo transfer strategies to enable the calculation of the long-term cost-effectiveness. Discussion This is, to our knowledge, the first study that investigates the long-term costs and health outcomes of IVF singleton and twin children and the long-term cost-effectiveness of single embryo transfer strategies versus double embryo transfer strategies. PMID:20961411

2010-01-01

279

Optically enhanced charge transfer between C60 and single-wall carbon nanotubes in hybrid electronic devices.  

PubMed

In this article we probe the nature of electronic interactions between the components of hybrid C60-carbon nanotube structures. Utilizing an aromatic mediator we selectively attach C60 molecules to carbon nanotube field-effect transistor devices. Structural characterization via atomic force and transmission electron microscopy confirm the selectivity of this attachment. Charge transfer from the carbon nanotube to the C60 molecules is evidenced by a blue shift of the Raman G(+) peak position and increased threshold voltage of the transistor transfer characteristics. We estimate this charge transfer to increase the device density of holes per unit length by up to 0.85 nm(-1) and demonstrate further optically enhanced charge transfer which increases the hole density by an additional 0.16 nm(-1). PMID:24241690

Allen, Christopher S; Liu, Guoquan; Chen, Yabin; Robertson, Alex W; He, Kuang; Porfyrakis, Kyriakos; Zhang, Jin; Briggs, G Andrew D; Warner, Jamie H

2014-01-01

280

PREDICTION OF UNLEARNED POSITION BASED ON LOCAL REGRESSION FOR SINGLE-CHANNEL TALKER LOCALIZATION USING ACOUSTIC TRANSFER FUNCTION  

E-print Network

techniques, such as MUSIC, CSP, and so on (e.g., [1, 2]), use simultaneous phase information from micro of impulse responses is not required. Us- ing the separated acoustic transfer function, the talker's position

Takiguchi, Tetsuya

281

Patient-Specific Embryonic Stem Cells Derived from Human SCNT Blastocysts  

Microsoft Academic Search

Patient-specific, immune-matched human embryonic stem cells (hESCs) are anticipated to be of great biomedical importance for studies of disease and development and to advance clinical deliberations regarding stem cell transplantation. Eleven hESC lines were established by somatic cell nuclear transfer (SCNT) of skin cells from patients with disease or injury into donated oocytes. These lines, nuclear transfer (NT)-hESCs, grown on

Woo Suk Hwang; Sung Il Roh; Byeong Chun Lee; Sung Keun Kang; Dae Kee Kwon; Sue Kim; Sun Jong Kim; Sun Woo Park; Hee Sun Kwon; Chang Kyu Lee; Jung Bok Lee; Jin Mee Kim; Curie Ahn; Sun Ha Paek; Sang Sik Chang; Jung Jin Koo; Hyun Soo Yoon; Jung Hye Hwang; Youn Young Hwang; Ye Soo Park; Sun Kyung Oh; Hee Sun Kim; Jong Hyuk Park; Shin Yong Moon; Gerald Schatten

2005-01-01

282

Heat transfer characteristics from an array of thin strips pin fins due to their exposures to a single downward jet impingement  

NASA Astrophysics Data System (ADS)

This paper investigates the heat transfer characteristics from thin strips pin fins due to their exposure to a single circular downward air jet impingement. Five aluminum specimens were considered; each one has a rectangular base of 84 mm × 78 mm and it has an array of about 300 thin strips pin fins. A test rig consists mainly of air compressor; nozzle and protractor mechanism was setup. Experiments were done to find out the effects of attack angle, Reynolds number, nozzle-to-target spacing, lateral pitch and parallel pitch among the fins on the heat transfer characteristics. Empirical correlations were deduced to describe the experimental data. A CFD-numerical model was introduced to monitor the flow characteristics on a scale of more details than that possible in the experimental work. The comparison among the results of the present work and those by the literature shows about 50% improvement in heat transfer characteristics rather than the single jet impingement onto flat plates, cylindrical surfaces, ribbed walls and multiple jets impingement onto flat plates.

Eid, Eldesouki I.; Gomaa, Abdalla G.; Gomaa, Mohamed E.

2011-02-01

283

Establishment of bovine trophoblast stem-like cells from in vitro-produced blastocyst-stage embryos using two inhibitors.  

PubMed

The trophoblast (TR) is the first to differentiate during mammalian embryogenesis and play a pivotal role in the development of the placenta. We used a dual inhibitor system (PD0325901 and CHIR99021) with mixed feeders to successfully obtain bovine trophoblast stem-like (bTS) cells, which were similar in phenotype to mouse trophoblast stem cells (TSCs). The bTS cells that were generated using this system continually proliferated, displayed a normal diploid karyotype, and had no signs of altered morphology or differentiation even after 150 passages. These cells exhibited alkaline phosphatase (AP) activity and expressed pluripotency markers, such as OCT4, NANOG, SOX2, SSEA-1, SSEA-4, TRA-1-60, and TRA-1-81, and TR lineage markers such as CDX2, as determined by both immunofluorescence and reverse transcription-polymerase chain reaction (RT-PCR). Additionally, these cells generated dome-like structures, formed teratomas when injected into NOD-SCID mice, and differentiated into placenta TR cells in vitro. The microarray analysis of bTS cells showed high expression levels of many TR markers, such as TEAD4, EOMES, GATA3, ETS2, TFAP2A, ELF5, SMARCA4 (BRG1), CDH3, MASH2, HSD17B1, CYP11A1, PPARG, ID2, GCM1, HAND1, TDK, PAG, IFN-?, and THAP11. The expression of many pluripotency markers, such as OCT4, SOX2, NANOG, and GDF3, was lower in bTS cells compared with in vitro-produced blastocysts; however, compared with bovine fetal fibroblasts, the expression of these pluripotency markers was elevated in bTS cells. The DNA methylation status of the promoter regions of OCT4, NANOG, and SOX2 was investigated, which were significantly higher in bTS cells (OCT4 23.90%, NANOG 74.40%, and SOX2 8.50%) compared with blastocysts (OCT4 8.90%, NANOG 34.4%, and SOX2 3.80%). In contrast, two promoter regions of CDX2 were hypomethylated in bTS cells (13.80% and 3.90%) compared with blastocysts (18.80% and 9.10%). The TSC lines that were established in this study may be used either for basic research that is focused on peri-implantation and placenta development or as donor cells for transgenic animal production. PMID:24605918

Huang, Xianghua; Han, Xuejie; Uyunbilig, Borjigin; Zhang, Manling; Duo, Shuguang; Zuo, Yongchun; Zhao, Yuhang; Yun, Ting; Tai, Dapeng; Wang, Chen; Li, Jinhua; Li, Xueling; Li, Rongfeng

2014-07-01

284

Novel energy transfer mechanism in single-phased color-tunable Sr2CeO4:Eu3+ phosphors for WLEDs  

NASA Astrophysics Data System (ADS)

A series of color-tunable Sr2CeO4:Eu3+ phosphors have been successfully synthesized. The Rietveld refinement was firstly used to probe the phase purity and the structure of Sr2CeO4:Eu3+. The photoluminescence excitation spectra exhibit that the phosphors show a broad excitation band from 200 to 400 nm, which concurs well with the commercial near-UV LED. The photoluminescence spectra vary with the dopant content due to the energy transfer and the tunable blue-red color can be simply achieved by altering the doped Eu3+ ions concentrations. On the basis of the Inokuti-Hirayama theory, we obtained that the dipole-dipole interaction type takes charge for the energy transfer from the Ce4+-O2- charge-transfer state transition to Eu3+ ions and the schematic was plotted to illuminate the possible energy transfer process. The experimental results indicate that Sr2CeO4:Eu3+ phosphors may be potentially used as promising single-phased phosphors for near-UV white light-emitting diodes applications.

Li, Haifeng; Jia, Yonglei; Sun, Wenzhi; Zhao, Ran; Fu, Jipeng; Jiang, Lihong; Zhang, Su; Pang, Ran; Li, Chengyu

2014-09-01

285

Fluorescence probing of nucleic acids: I. Singly and doubly labeled dithymidine phosphate: fluorescence and energy transfer studies.  

PubMed Central

Dithymidine phosphate labeled at its 5' end with a naphthalene-carbamate has been prepared,DTpT. It is shown to exist in several conformations which are characterized by chromatography and absorption and fluorescence measurements. Models for three possible conformers where the dye is solvated, stacked on the first thymine or intercalated between the two thymines are given with their absorption and fluorescence spectra. The doubly labeled molecule,DTpTA, where D and A form a donor-acceptor energy transfer pair has also been prepared. The energy transfer rate has been measured from the donor fluorescence lifetime decay. Images PMID:1178519

Tournon, J

1975-01-01

286

Extending light-harvesting of poly(3-hexylthiophene) through efficient energy transfer from infra-red absorbing nanocrystals: Single nanoparticle study  

NASA Astrophysics Data System (ADS)

We report on single nanocrystal fluorescence microscopy of blends composed of colloidal up-converting NaYF4 nanocrystals doped with rare-earth ions embedded in poly(3-hexylthiophene) (P3HT) polymer. By probing both steady-state and time-resolved fluorescence properties of individual nanocrystals excited with infra-red 980 nm laser, we demonstrate that upon up-conversion to the visible spectral range, the energy is efficiently transferred from the nanocrystals to P3HT. From the analysis of fluorescence lifetimes, the energy transfer efficiency for 550 nm emission of the nanocrystals was estimated to be 60%. This observation renders the up-converting nanocrystals as potential structures for improving light-harvesting efficiency of polymers in the near-infrared spectral region.

Grzelak, Justyna; Ciszak, Kamil; Nyk, Marcin; Mackowski, Sebastian; Piatkowski, Dawid

2014-10-01

287

Novel diode laser-compatible fluorophores and their application to single molecule detection, protein labeling and fluorescence resonance energy transfer immunoassay.  

PubMed

We describe a series of new long-wave absorbing and fluorescing cyanine dyes and labels (based on a general logic for the design of such dyes), their spectra, covalent and noncovalent linkage to proteins, their use in single molecule detection (SMD) and as donors and acceptors, respectively, in fluorescence resonance energy transfer studies. The new labels represent water-soluble and reactive fluorophores whose quantum yields increase substantially if noncovalently or covalently bound to proteins. Due to their strong absorptions between 550 and 700 nm they are excitable by light-emitting diodes or diode lasers. Their high absorbances (epsilon around 100,000) and adequate fluorescence quantum yields (phi up to 0.68 if bound to proteins) along with their availability as reactive NHS esters make them viable labels for proteins and oligomers, e.g. in context with SMD or fluorescence energy transfer immunoassay which is demonstrated for the system HSA/anti-HSA. PMID:11547561

Oswald, B; Gruber, M; Böhmer, M; Lehmann, F; Probst, M; Wolfbeis, O S

2001-08-01

288

On the definition of dominant force regimes for flow boiling heat transfer by using single mini-tubes  

Microsoft Academic Search

Recent increase in the size of space platforms requires the management of larger amount of waste heat under high heat flux conditions and the transportation of it along a long distance to the radiator. Flow boiling applied to the thermal management system in space attracts much attention as promising means to realize high-performance heat transfer and transport because of large

Soumei Baba; Kenichiro Sawada; Chisato Kubota; Osamu Kawanami; Hitoshi Asano; Koichi Inoue; Haruhiko Ohta

2010-01-01

289

Epigenetic control of cell-fate in mouse blastocysts: role of covalent histone modifications and chromatin remodeling  

PubMed Central

Summary The first cell fate decision in mammalian preimplantation embryos is the segregation of the inner cell mass (ICM) and trophectoderm (TE) cell lineages. The ICM develops into the embryo proper, whereas the TE ensures embryo implantation and is the source of the extra-embryonic trophoblast cell lineages, which build the functional co-units of the placenta. The development of a totipotent zygote into a multilineage blastocyst is associated with the generation of distinct transcriptional programs. Several key transcription factors participate in the ICM and TE-specific transcriptional networks and recent studies indicate that post-translational histone modifications as well as ATP-dependent chromatin remodeling complexes converge with these transcriptional networks to regulate ICM and TE lineage specification. This review will discuss our current understanding and future perspectives related to transcriptional and epigenetic regulatory mechanisms that are implicated in first mammalian lineage commitment in mice. PMID:23893501

Paul, Soumen; Knott, Jason G.

2014-01-01

290

Transfer-printing of single DNA molecule arrays on graphene for high resolution electron imaging and analysis  

PubMed Central

Graphene represents the ultimate substrate for high-resolution transmission electron microscopy, but the deposition of biological samples on this highly hydrophobic material has until now been a challenge. We present a reliable method for depositing ordered arrays of individual elongated DNA molecules on single-layer graphene substrates for high resolution electron beam imaging and electron energy loss spectroscopy analysis. This method is a necessary step towards the observation of single elongated DNA molecules with single base spatial resolution to directly read genetic and epigenetic information. PMID:21919532

Cerf, Aline; Alava, Thomas; Barton, Robert A.; Craighead, Harold G.

2011-01-01

291

Single electron transfer (SET) activity of the dialkyl-amido sodium zincate [(TMEDA)·Na(?-TMP)(?-tBu)Zn(tBu)] towards TEMPO and chalcone.  

PubMed

More usually thought of as a base, the sodium zincate [(TMEDA)·Na(?-TMP)(?-(t)Bu)Zn((t)Bu)] 1 can undergo single electron transfer with TEMPO to give [(TMEDA)·Na(?-TMP)(?-TEMPO(-))Zn((t)Bu)] 2 and [(TMEDA)·Na(?-TEMPO(-))(2)Zn((t)Bu)] 3; and with chalcone [PhCOCH=CHPh] gives [{(TMEDA)·Na(?-TMP)Zn((t)Bu)}(2)(?-OCPhCH=CHPhCHPhCH=CPh-?-O)] which contains two chalcone units C-C coupled though their benzylic C atoms. PMID:21687848

Armstrong, D R; Balloch, L; Crawford, J J; Fleming, B J; Hogg, L M; Kennedy, A R; Klett, J; Mulvey, R E; O'Hara, Charles T; Orr, S A; Robertson, S D

2012-02-01

292

Significant improvement of mouse cloning technique by treatment with trichostatin A after somatic nuclear transfer  

SciTech Connect

The low success rate of animal cloning by somatic cell nuclear transfer (SCNT) is believed to be associated with epigenetic errors including abnormal DNA hypermethylation. Recently, we elucidated by using round spermatids that, after nuclear transfer, treatment of zygotes with trichostatin A (TSA), an inhibitor of histone deacetylase, can remarkably reduce abnormal DNA hypermethylation depending on the origins of transferred nuclei and their genomic regions [S. Kishigami, N. Van Thuan, T. Hikichi, H. Ohta, S. Wakayama. E. Mizutani, T. Wakayama, Epigenetic abnormalities of the mouse paternal zygotic genome associated with microinsemination of round spermatids, Dev. Biol. (2005) in press]. Here, we found that 5-50 nM TSA-treatment for 10 h following oocyte activation resulted in more efficient in vitro development of somatic cloned embryos to the blastocyst stage from 2- to 5-fold depending on the donor cells including tail tip cells, spleen cells, neural stem cells, and cumulus cells. This TSA-treatment also led to more than 5-fold increase in success rate of mouse cloning from cumulus cells without obvious abnormality but failed to improve ES cloning success. Further, we succeeded in establishment of nuclear transfer-embryonic stem (NT-ES) cells from TSA-treated cloned blastocyst at a rate three times higher than those from untreated cloned blastocysts. Thus, our data indicate that TSA-treatment after SCNT in mice can dramatically improve the practical application of current cloning techniques.

Kishigami, Satoshi [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan)]. E-mail: kishigami@cdb.riken.jp; Mizutani, Eiji [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Ohta, Hiroshi [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Hikichi, Takafusa [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Thuan, Nguyen Van [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Wakayama, Sayaka [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Bui, Hong-Thuy [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan); Wakayama, Teruhiko [Laboratory for Genomic Reprogramming, Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima-minamimachi, Kobe 650-0047 (Japan)

2006-02-03

293

Reduced Dielectric Screening and Enhanced Energy Transfer in Single- and Few-Layer MoS2  

NASA Astrophysics Data System (ADS)

We report highly efficient non-radiative energy transfer from cadmium selenide (CdSe) quantum dots to monolayer and few-layer molybdenum disulfide (MoS2). The quenching of the donor quantum dot photoluminescence increases as the MoS2 flake thickness decreases, with the highest efficiency (>95%) observed for monolayer MoS2. This counterintuitive result arises from reduced dielectric screening in thin layer semiconductors having unusually large permittivity and a strong in-plane transition dipole moment, as found in MoS2. Excitonic energy transfer between a 0D emitter and a 2D absorber is fundamentally interesting and enables a wide range of applications including broadband optical down-conversion, optical detection, photovoltaic sensitization, and color shifting in light-emitting devices.

Prins, Ferry; Goodman, Aaron J.; Tisdale, William A.

2014-11-01

294

Cytochrome P450-catalyzed dealkylation of atrazine by Rhodococcus sp. strain NI86/21 involves hydrogen atom transfer rather than single electron transfer.  

PubMed

Cytochrome P450 enzymes are responsible for a multitude of natural transformation reactions. For oxidative N-dealkylation, single electron (SET) and hydrogen atom abstraction (HAT) have been debated as underlying mechanisms. Combined evidence from (i) product distribution and (ii) isotope effects indicate that HAT, rather than SET, initiates N-dealkylation of atrazine to desethyl- and desisopropylatrazine by the microorganism Rhodococcus sp. strain NI86/21. (i) Product analysis revealed a non-selective oxidation at both the ?C and ?C-atom of the alkyl chain, which is expected for a radical reaction, but not SET. (ii) Normal (13)C and (15)N as well as pronounced (2)H isotope effects (?carbon: -4.0‰ ± 0.2‰; ?nitrogen: -1.4‰ ± 0.3‰, KIEH: 3.6 ± 0.8) agree qualitatively with calculated values for HAT, whereas inverse (13)C and (15)N isotope effects are predicted for SET. Analogous results are observed with the Fe(iv)[double bond, length as m-dash]O model system [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin-iron(iii)-chloride + NaIO4], but not with permanganate. These results emphasize the relevance of the HAT mechanism for N-dealkylation by P450. PMID:24851834

Meyer, Armin H; Dybala-Defratyka, Agnieszka; Alaimo, Peter J; Geronimo, Inacrist; Sanchez, Ariana D; Cramer, Christopher J; Elsner, Martin

2014-08-28

295

Experimental investigation of fluid flow and heat transfer in a single-phase liquid flow micro-heat exchanger  

Microsoft Academic Search

This work presents an experimental analysis of the hydrodynamic and thermal performance of micro-heat exchangers. Two micro-heat exchangers, characterized by microchannels of 100×100 and 200×200?m square cross-sections, were designed for that purpose. The fluid used was deionized water and there was no phase change along the fluid circuit. The fluid pressure drop along the heat exchanger and the heat transfer

N. García-Hernando; A. Acosta-Iborra; U. Ruiz-Rivas; M. Izquierdo

2009-01-01

296

Experimental and numerical investigation of single-phase heat transfer using a hybrid jet-impingement\\/micro-channel cooling scheme  

Microsoft Academic Search

Experimental and numerical methods were used to explore the cooling performance of a new hybrid device consisting of a slot jet impinging into a micro-channel, thus capitalizing upon the merits of both cooling configurations. The three-dimensional heat transfer characteristics of this device were analyzed using the standard k–? turbulent model. Numerical predictions for liquid PF-5052 show excellent agreement with experimental

Myung Ki Sung; Issam Mudawar

2006-01-01

297

The effect of estrogen administration during early pregnancy upon the survival of single implanted pig embryos.  

PubMed

In the present study, we investigated the influence of exogenous estrogen on embryo survival after transfer into prepubertal gilts in which estrus had been induced. In the first experiment, estrus was induced in prepubertal gilts by the administration of 1,000 IU of eCG and 750 IU of hCG every 72 h. Several blastocysts were recovered on d 6 (d 0 is the day of hCG administration), and 1 embryo was transferred to the tip of 1 side of the uterine horn on d 6 (Control). In treated groups, after embryo transfer, 5 mg of estradiol benzoate (EB) was administered on d 11 (EB5mg-1) or d 11, d 13, and d 15 (EB5mg-3) or d 11, 12, 13, 14, and 15 (EB5mg-5) or 20 mg of estradiol dipropionate (EDP) was administered on d 11 (EDP20mg-1) or d 11 and d 14 (EDP20mg-2). Autopsy examinations were performed on d 53 to 60. Although nontreated gilts did not become pregnant, gilts in each of the estradiol-treated groups became pregnant. The greatest pregnancy rate (77.8%, 7/9) was obtained with EDP20mg-2 (EDP20mg-2 > control: P < 0.05). In a second experiment, 1 blastocyst was transferred to prepubertal gilts and treated with EDP20mg-2. Pregnancy in recipient pigs was confirmed by ultrasonography, and pigs were allowed to farrow. Embryo survival rate was high on d 30 of pregnancy (75%, 9/12) but had a tendency (P = 0.0995) to decline from d 30 to delivery (33.3%, 4/12). In a third experiment, prepubertal gilts were administered 5 mg of EDP on d 11 (EDB5mg-1) and d 11 and d 14 (EDP5mg-2). Autopsy examinations were performed on d 53 to 58. Pseudopregnancy rate was high for EDP5mg-2 (63.6%, 7/11) compared with EDP5mg-1 (0%, 0/11; P < 0.05). In a fourth experiment, prepubertal gilts were transferred 1 blastocyst and treated with EDP5mg-2. Pregnancy was confirmed in recipient pigs by ultrasonography, and pigs were subsequently allowed to farrow. Embryo survival rate remained unchanged from d 30 of pregnancy to delivery (66.7%; 8/12). One piglet died from dystocia, and 1 suffered from deformity involving double-breasted hooves and died 6 d after birth. There was no difference (P > 0.05) in survival rate on d 30 of pregnancy and weaning (50%, 6/12). Body weight at birth and at weaning did not differ from that reported in previous studies. In conclusion, this study showed that EDP5mg-2 treatment during early pregnancy leads to full-term development of a single embryo. PMID:22829621

Kawarasaki, T; Enya, S; Otsu, Y

2012-12-01

298

200 mm wafer-scale epitaxial transfer of single crystal Si on glass by anodic bonding of silicon-on-insulator wafers  

NASA Astrophysics Data System (ADS)

We report a low-temperature (350 °C) anodic bonding followed by grind/etch-back method for a 200 mm wafer-scale epitaxial transfer of ultrathin (1.9 kÅ) single crystalline Si on Pyrex glass. Standard back-end-of-line 3 kÅ SiN/3 kÅ undoped silicon glass passivating films were used as the buffer layers between the silicon-on-insulator wafer and the glass wafer. The quality and strain-free state of the transferred transparent Si film to glass was characterized by cross-sectional transmission electron microscopy, x-ray diffraction (XRD), and high-resolution XRD. Complete removal of the bulk Si after bonding was ascertained by Auger electron spectroscopy spectra and depth profiling. Strong adhesion between the transferred film and the glass wafer was verified by standard tape adhesion tests. This process will pave the way for future generations of Si-based microelectronics including bioelectronics.

Teh, W. H.; Trigg, Alastair; Tung, C. H.; Kumar, R.; Balasubramanian, N.; Kwong, D. L.

2005-08-01

299

Single-chain surfactant monolayer on carbon paste electrode and its application for the studies on the direct electron transfer of hemoglobin.  

PubMed

A variety of single-chain surfactants with different charge properties and tail lengths can spontaneously adsorb on the hydrophobic surface of carbon paste electrode and form stable monolayers on the electrode surface. Hemoglobin (Hb) was successfully immobilized on these surfactant monolayers to form stable protein-surfactant composite films regardless of the charge and the tail length of surfactants. The resulting surface-confined Hb exhibited well-defined direct electron-transfer behaviors in all positively, neutrally and negatively charged surfactant films, suggesting the important role of hydrophobic interactions in the adsorption of Hb on surfactant films. When the density of surfactant monolayers was controlled to be the same, Hb was found to possess a better direct electron-transfer behavior on monolayers of cationic surfactants with a longer tail length. This, in combination with the tunneling effect in the direct electron transfer of Hb on surfactant films, demonstrated that the adsorption of Hb on surfactant monolayers may be mainly achieved by the partial intercalation of Hb in the loose structures of surfactant films through hydrophobic interactions between the alkane chains of surfactants and the hydrophobic regions of Hb. The native conformation of Hb adsorbed on these surfactant films was proved to be unchanged, reflected by the unaltered ultraviolet-visible (UV-vis) and reflection-absorption infrared (RAIR) spectra, and by the catalytic activity toward hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) in comparison with the free Hb molecules. PMID:18938113

Xu, Yanxia; Hu, Chengguo; Hu, Shengshui

2009-02-01

300

Enhanced Förster Resonance Energy Transfer on Single Metal Particle. 2. Dependence on Donor–Acceptor Separation Distance, Particle Size, and Distance from Metal Surface  

PubMed Central

We studied the effect of metal particles on Förster resonance energy transfer (FRET) between nearby donor–acceptor pairs. The studies included the effect of donor–acceptor distance, silver particle size, and distance from the metal surface. The metal particles were synthesized with average diameters of 15, 40, and 80 nm, respectively. A Cy5-labeled oligonucleotide was chemically bound to a single silver particle with a distance of 2 or 10 nm from the surface of metal core. A Cy5.5-labeled complementary oligonucleotide was bound to the particle-conjugated oligonucleotide by hybridization. The spacer length between donor–acceptor was adjusted by the number of base pairs. FRET between the donor–acceptor pair was investigated by dual-channel single-molecule fluorescence detection. Both the emission intensities and lifetimes indicated that FRET was enhanced efficiently by the metal particles. The results showed an increase of apparent energy transfer distance with the size of silver particle and distance from the metal core. Simulations by finite-difference time-domain (FDTD) calculations were used to compare with the experimental results. The local fields at the location of the donor–acceptor pair appeared to correlate with the FRET efficiency. These results will aid in the design of metal particles for using FRET to determine biomolecule proximity at distances beyond the usual Förster distance. PMID:19890406

Zhang, Jian; Fu, Yi; Chowdhury, Mustafa H.; Lakowicz, Joseph R.

2009-01-01

301

Effect of melatonin treatment on developmental potential of somatic cell nuclear-transferred mouse oocytes in vitro.  

PubMed

The beneficial effect of supplementing culture medium with melatonin has been reported during in vitro embryo development of species such as mouse, bovine and porcine. However, the effect of melatonin on mouse somatic cell nuclear transfer remains unknown. In this study, we assessed the effects of various concentrations of melatonin (10-6 to 10-12 M) on the in vitro development of mouse somatic cell nuclear transfer embryos for 96 h. Embryos cultured without melatonin were used as control. There was no significant difference in cleavage rates between the groups supplemented with melatonin, dimethyl sulphoxide (DMSO) and the control. The rate of development to blastocyst stage was significantly higher in the group supplemented with 10-12 M melatonin compared with the control group (P < 0.05). Thus, our data demonstrated that adding melatonin to pre-implantation mouse nuclear-transferred embryos can accelerate blastocyst formation. PMID:24040915

Salehi, Mohammad; Kato, Yoko; Tsunoda, Yukio

2014-05-01

302

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo).  

PubMed

Embryo transfer (ET) to recipient females is a foundational strategy for a number of assisted reproductive technologies, including cloning by somatic cell nuclear transfer. In an attempt to develop efficient ET in domestic ferrets, factors affecting development of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts in the oviduct or uterus was evaluated in recipient nulliparous or primiparous females. Developing fetuses were collected from recipient animals 21 days post-copulation and examined. The percentage of fetal formation was different (P<0.05) for unilateral and bilateral transfer of zygotes (71%) in nulliparous females with bilateral transfer (56%) in primiparous recipients. The percentage (90%) of fetal formation in nulliparous recipients following unilateral transfer of blastocysts was higher (P<0.05) than that observed in primiparous recipients with bilateral ET (73%). Notably, the percentage of fetal formation was higher (P<0.05) when blastocyts were transferred as compared to zygotes (90% versus 71%). Transuterine migration of embryos occurred following all unilateral transfers and also in approximately 50% of bilateral transfers with different number of embryos in each uterine horn. These data will help to facilitate the development of assisted reproductive strategies in the ferret and could lead to the use of this species for modeling human disease and for conservation of the endangered Mustelidae species such as black-footed ferret and European mink. PMID:16330092

Li, Ziyi; Sun, Xingshen; Chen, Juan; Leno, Gregory H; Engelhardt, John F

2006-07-15

303

Heat and mass transfer at a free surface with diabatic boundaries in a single-species system under microgravity conditions  

NASA Astrophysics Data System (ADS)

In this paper, we analyzed the heat and mass transfer at a free surface under microgravity conditions. The SOURCE-II (Sounding Rocket COMPERE Experiment) experiment was performed on a suborbital flight in February 2012 from Esrange in North Sweden. It provided representative data with respect to solid, liquid, and vapor temperatures as well as the visible surface position. The objectives were to quantify the deformation of the free liquid surface and to correlate the apparent contact angle to a characteristic temperature difference between subcooled liquid and superheated wall. Furthermore, the influence of evaporation and condensation at the liquid/vapor interface and at the superheated wall must be taken into account to analyze heat and mass fluxes due to a characteristic temperature difference. In the following, we show evidently that the magnitude of the apparent contact angle depends on the exerted specific pressurizations of the vapor phase during the experiment and hence on the change in the saturation temperature at the free surface. The characteristic temperature difference is defined with respect to the wall temperature in the vicinity of the contact line and the saturation temperature. Therefore, apparent contact angle and temperature difference can be correlated and indicate a specific characteristic. Concerning the heat and mass transfer at the free liquid surface and the contact line, two different methods are presented to evaluate the net mass due to phase change within a certain time interval. In the first approach, the mass flow rate is calculated by means of the ideal gas law and its derivatives with respect to temperature and pressure. The second approach calculates the heat flux as well as the mass flux at the wall and in the region of the free liquid surface. In these cases, a specific heat transfer coefficient and a thermal boundary layer thickness are used.

Fuhrmann, Eckart; Dreyer, Michael E.

2014-06-01

304

Large aperture deformable mirror with a transferred single-crystal silicon membrane actuated using large-stroke PZT Unimorph Actuators  

NASA Technical Reports Server (NTRS)

We have demonstrated a large aperture (50 mm x 50 mm) continuous membrane deformable mirror (DM) with a large-stroke piezoelectric unimorph actuator array. The DM consists of a continuous, large aperture, silicon membrane 'transferred' in its entirety onto a 20 x 20 piezoelectric unimorph actuator array. A PZT unimorph actuator, 2.5 mm in diameter with optimized PZT/Si thickness and design showed a deflection of 5.7 [m at 20V. An assembled DM showed an operating frequency bandwidth of 30 kHz and influence function of approximately 30%.

Hishinumat, Yoshikazu; Yang, Eui - Hyeok (EH)

2005-01-01

305

Microjet array single-phase and flow boiling heat transfer with R134a Eric A. Browne a  

E-print Network

of a submerged microjet array was conducted with R134a. The staggered array of seventeen 112-lm diameter orifices studies have been performed [25­30] but mostly with single jets. This study employs an array of submerged the pressure in the loop. Pre- scribed inlet temperatures were achieved

Peles, Yoav

306

Statistics and kinetics of single-molecule electron transfer dynamics in complex environments: a simulation model study.  

PubMed

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments can be revealed. We consider real experimental conditions with finite observation time windows. At high temperatures, exponential kinetics is observed and there are multiple kinetic paths leading to the product state. At and below an intermediate temperature, nonexponential kinetics starts to appear, revealing the nature of the distribution of local traps on the landscape. Discrete kinetic paths emerge. At very low temperatures, nonexponential kinetics continues to be observed. We point out that the size of the observational time window is crucial in revealing the intrinsic nature of the real kinetics. The mean first-passage time is defined as a characteristic time. Only when the observational time window is significantly larger than this characteristic time does one have the opportunity to collect enough statistics to capture rare statistical fluctuations and characterize the kinetics accurately. PMID:19071925

Paula, Luciana C; Wang, Jin; Leite, Vitor B P

2008-12-14

307

Statistics and kinetics of single-molecule electron transfer dynamics in complex environments: A simulation model study  

SciTech Connect

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments can be revealed. We consider real experimental conditions with finite observation time windows. At high temperatures, exponential kinetics is observed and there are multiple kinetic paths leading to the product state. At and below an intermediate temperature, nonexponential kinetics starts to appear, revealing the nature of the distribution of local traps on the landscape. Discrete kinetic paths emerge. At very low temperatures, nonexponential kinetics continues to be observed. We point out that the size of the observational time window is crucial in revealing the intrinsic nature of the real kinetics. The mean first-passage time is defined as a characteristic time. Only when the observational time window is significantly larger than this characteristic time does one have the opportunity to collect enough statistics to capture rare statistical fluctuations and characterize the kinetics accurately.

Paula, Luciana C. [Departamento de Fisica, Instituto de Biociencias Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto, Sao Paulo 15054-000 (Brazil); Departamento de Estudos Basicos e Instrumentais, Universidade Estadual do Sudoeste da Bahia, Itapetinga, Bahia 45700-000 (Brazil); Wang Jin [Department of Chemistry, Physics and Applied Mathematics, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry of Chinese Academy of Sciences, Changchun 130022 (China); Leite, Vitor B. P. [Departamento de Fisica, Instituto de Biociencias Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto, Sao Paulo 15054-000 (Brazil)

2008-12-14

308

341 feline embryonic stem-like cells derived from in vitro-produced blastocysts retain in vitro differentiation potential.  

PubMed

Embryonic stem (ES) cells are pluripotent cells that can differentiate into all 3 germ layers, including endoderm, mesoderm, and ectoderm. Embryonic stem cells are generally divided into 2 types, naïve and primed-state, depending on their signaling pathways. Domestic cat is a useful animal model for the study of human diseases because many genetic and infectious diseases in the cat are analogous with similar aetiology to human diseases. The cat can also be used as a research model for reproductive physiology and conservation of wild felids. Until recently, information on establishment of feline ES cells is limited. The objectives of this study were to isolate cat ES cells from in vitro-produced blastocysts and to examine the effect of different concentrations of basic fibroblast growth factor (bFGF) on the expression of pluripotent genes. Inner cell masses (ICM) from cat blastocysts (n=40, Day 7 after in vitro fertilization) that were matured, fertilized, and cultured entirely in vitro, were isolated by immunosurgery and plated on mitmycin-treated mouse embryonic fibroblasts. The ICM (n=20) were then cultured in embryonic stem cell medium containing 1000IUmL(-1) of leukemia inhibitory factor (LIF) and different bFGF concentrations (0, 4, 10, and 20ngmL(-1)). The ICM outgrowths at 7 days postplating were collected and analysed for expression of pluripotent genes (SOX-2, OCT-4, and NANOG). Results showed that transcription levels of all 3 pluripotent genes were higher in ICM outgrowths cultured in 20ngmL(-1) of bFGF compared with the lower concentrations. For isolation of ES cells, ICM (n=20) were cultured in embryonic stem cell medium supplemented with 1000IUmL(-1) of LIF and 20ngmL(-1) of bFGF due to the results obtained from the above experiment. Established ES cells were characterised by detecting alkaline phosphatase (AP) activity and expression of ES markers (SOX-2, OCT-4, SSEA-4) at protein level, and karyotyped at passage 20 and 40. In vitro differentiation into embryoid bodies (EB) was induced by the hanging drop technique, and EB samples (n=5 for each time point) were tested for the expression of TTR, AFP, T (Bracyury), NKX2.5, MAP-2, and NESTIN genes at 0, 7, and 14 days of culture. A total of 3 ES-like cell lines were established with a typical ES morphology, such as a well-defined colony, a large nucleus to cytoplasm ratio with 1 to 2 prominent nucleoli. The 3 ES-like cell lines were passaged up to 40 times with a normal diploid karyotype (n=38). They were strongly positive for AP, SOX-2, OCT-4, and SSEA-4. Following EB culture, cell aggregation and cystic-like structure were observed. The EB samples also expressed all differentiation markers. This study reports that feline ES-like cell lines can be generated from in vitro-produced feline blastocysts. The ES cell lines can be repeatedly passaged indicating self-renewal ability, and gene expression of the EB demonstrates cellular differentiation into all 3 germ layers. PMID:25472389

Tharasanit, T; Tiptanavattana, N; Phakdeedindan, P; Techakumphu, M

2014-12-01

309

Single-stage surgery combining nerve and tendon transfers for bilateral upper limb reconstruction in a tetraplegic patient: case report.  

PubMed

A 39-year-old tetraplegic patient had paralysis of elbow, thumb, and finger extension and thumb and finger flexion. We transferred axillary nerve branches to the triceps long and upper medial head motor branches, supinator motor branches to the posterior interosseous nerve, and brachioradialis tendon to the flexor pollicis longus and flexor superficialis of the index finger. Surgery was performed bilaterally 18 months after spinal cord injury. At 12 months after surgery, we performed bilateral distal radioulnar arthrodesis percutaneously. By 22 months postoperatively, we observed triceps strength scoring M3 bilaterally and full metacarpophalangeal joint extension scoring M4 bilaterally. The thumb span was 53 and 66 mm from the proximal index phalanx on the right and left sides, respectively. Pinch strength measured 1.5 kg on the left side and 2.0 kg on the right. Before surgery, the patient was incapable of grasping; after surgery, a useful grasp had been restored bilaterally. PMID:23751324

Bertelli, Jayme Augusto; Ghizoni, Marcos Flávio

2013-07-01

310

Modified transfer matrix method model for a fiber Bragg grating strain sensor in polarization maintaining single mode optical fiber  

NASA Astrophysics Data System (ADS)

Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, EMI immunity, high sensitivity, and multiple multiplexing schemes, as compared to conventional electricity based strain sensors. FBG sensors written in Polarization Maintaining (PM) optical fiber offer an additional dimension of strain measurement simplifying sensor implementation within a structure. This simplification however, adds complexity to the detection of the sensor's optical response to its corresponding applied strain. We propose a modified Transfer Matrix Method model to simulate a fiber Bragg grating (FBG) in a polarization maintaining optical fiber. We study the effects of the reflected Bragg wavelength to the changes in shape of the optical fiber core waveguide and compare the results to the existing literature.

Quintana, Joel; Rumpf, Raymond; Gonzalez, Virgilio

2014-03-01

311

In vitro development of porcine transgenic nuclear-transferred embryos derived from newborn Guangxi Bama mini-pig kidney fibroblasts.  

PubMed

Porcine transgenic cloning has potential applications for improving production traits and for biomedical research purposes. To produce a transgenic clone, kidney fibroblasts from a newborn Guangxi Bama mini-pig were isolated, cultured, and then transfected with red and green fluorescent protein genes using lipofectamine for nuclear transfer. The results of the present study show that the kidney fibroblasts exhibited excellent proliferative capacity and clone-like morphology, and were adequate for generation of somatic cell nuclear transfer (SCNT)-derived embryos, which was confirmed by their cleavage activity and blastocyst formation rate of 70.3% and 7.9%, respectively. Cells transfected with red fluorescent protein genes could be passed more than 35 times. Transgenic embryos cloned with fluorescent or blind enucleation methods were not significantly different with respect to cleavage rates (92.5% vs. 86.8%, p?>?0.05) and blastocyst-morula rates (26.9% vs. 34.0%, p?>?0.05), but were significantly different with respect to blastocyst rates (3.0% vs. 13.2%, p??0.05), blastocyst (14.1%, 16.1% vs. 23.1%, p?>?0.05) and morula/blastocyst rates (43.5%, 47.0% vs. 57.6%, p?>?0.05) were not significantly different between the groups of transgenic cloned embryos, cloned embryos, and parthenogenetic embryos. This indicates that long-time screening by G418 caused no significant damage to kidney fibroblasts. Thus, kidney fibroblasts represent a promising new source for transgenic SCNT, and this work lays the foundation for the production of genetically transformed cloned Guangxi Bama mini-pigs. PMID:24879084

Liu, Hongbo; Lv, Peiru; Zhu, Xiangxing; Wang, Xianwei; Yang, Xiaogan; Zuo, Erwei; Lu, Yangqing; Lu, Shengsheng; Lu, Kehuan

2014-10-01

312

Transfer of melamine from feed to milk and from milk to cheese and whey in lactating dairy cows fed single oral doses.  

PubMed

A study was conducted to evaluate the excretion pattern, after a single oral dose, of melamine from feed into milk, and the subsequent transfer to cheese and whey. The transfer of cyanuric acid was also investigated. Twenty-four lactating Holstein cows were randomly allocated to 4 treatments and received single doses of melamine as follows: 0.05, 0.50, 5.00, and 50.00 g/cow for groups D1, D2, D3, and D4, respectively. Individual milk samples were collected for melamine and cyanuric acid analyses on d 1, 2, 3, 4, 5, and 7. Milk collected individually from the second milking after melamine ingestion was used to make cheese on a laboratory scale. Melamine and cyanuric acid were extracted using a solid-phase extraction cartridge, and analyses were carried out by liquid chromatography-mass spectrometry/mass spectrometry. Maximal melamine concentrations occurred between 6 and 18 h after treatment and increased with log dose (linear and quadratic), ranging from 0.019 to 35.105 mg/kg. More than 60% of the melamine that was transferred to the milk was observed within 30 h after melamine ingestion. Melamine was not detected (limit of detection was 0.002 mg/kg) in milk 5 d after treatment in group D1, and 7 d after treatment in groups D2, D3, and D4. Blood urea nitrogen was not influenced by melamine ingestion. During cheese making, melamine was transferred mainly to the whey fraction. Cyanuric acid was not detected in any of the samples (milk, cheese, or whey). The excretion pattern of melamine in milk and whey may represent a health concern when cows ingest more than 0.50 g of melamine/d. However, only at intake levels of 5 and 50 g/d did cheese exceed the limits as set forth by the European Union. The results confirmed that melamine contamination of milk and milk products may be related not only to direct contamination, but also to adulteration of animal feeds. PMID:20965350

Battaglia, M; Cruywagen, C W; Bertuzzi, T; Gallo, A; Moschini, M; Piva, G; Masoero, F

2010-11-01

313

Comparison of male chimeric mice generated from microinjection of JM8.N4 embryonic stem cells into C57BL/6J and C57BL/6NTac blastocysts  

PubMed Central

To identify ways to improve the efficiency of generating chimeric mice via microinjection of blastocysts with ES cells, we compared production and performance of ES-cell derived chimeric mice using blastocysts from two closely related and commonly used sub-strains of C57BL/6. Chimeras were produced by injection of the same JM8.N4 (C57BL/6NTac) derived ES cell line into blastocysts of mixed sex from either C57BL/6J (B6J) or C57BL/6NTac (B6NTac) mice. Similar efficiency of production and sex-conversion of chimeric animals was observed with each strain of blastocyst. However, B6J chimeric males had fewer developmental abnormalities involving urogenital and reproductive tissues (1/12, 8%) compared with B6NTac chimeric males (7/9, 78%). The low sample size did not permit determination of statistical significance for many parameters. However, in each category analyzed the B6J-derived chimeric males performed as well, or better, than their B6NTac counterparts. Twelve of 14 (86%) B6J male chimeras were fertile compared with 6 of 11 (55%) B6NTac male chimeras. Ten of 12 (83%) B6J chimeric males sired more than 1 litter compared with only 3 of 6 (50%) B6NTac chimeras. B6J male chimeras produced more litters per productive mating (3.42 ± 1.73, n=12) compared to B6NTac chimeras (2.17 ± 1.33, n=6). Finally, a greater ratio of germline transmitting chimeric males was obtained using B6J blastocysts (9/14; 64%) compared with chimeras produced using B6NTac blastocysts (4/11; 36%). Use of B6J host blastocysts for microinjection of ES cells may offer improvements over blastocysts from B6NTac and possibly other sub-strains of C57BL/6 mice. PMID:22422470

Fielder, Thomas J.; Yi, Charles S.; Masumi, Juliet; Waymire, Katrina G.; Chen, Hsiao-Wen; Wang, Shuling; Shi, Kai-Xuan; Wallace, Douglas C.; MacGregor, Grant R.

2012-01-01

314

A single-phased tunable emission phosphor MgY2Si3O10: Eu(3+), Bi(3+) with efficient energy transfer for white LEDs.  

PubMed

A novel single-phased tunable emitting phosphor MgY2Si3O10: Bi(3+), Eu(3+) has been synthesized by a conventional high temperature solid-state method. X-ray diffraction (XRD), photoluminescence emission and excitation spectra were utilized to characterize the as-synthesized samples. Under UV-light pumping, MgY2Si3O10: Bi(3+) showed characteristic blue emission corresponding to the (3)P1?(1)S0 transition of Bi(3+) ions, and MgY2Si3O10: Eu(3+) showed characteristic red emission corresponding to the (5)D0?(7)FJ (J = 1, 2, 3, 4) transition of Eu(3+) ions. Spectra indicate that Bi(3+) ions occupy two nonequivalent sites in the MgY2Si3O10 matrix, namely, Bi(3+)(i) and Bi(3+)(ii). The two sites (Bi(3+)(i) and Bi(3+)(ii)) exhibit broad emission peaks at 411 nm and 490 nm, respectively. Efficient energy transfer between these two Bi(3+) sites has been proven using the spectra. The spectral overlap between the emission spectrum of Bi(3+) and the excitation spectrum of Eu(3+) allows for resonance-type energy transfer to occur from Bi(3+) to Eu(3+). The efficient energy transfer from Bi(3+) to Eu(3+)via a dipole-quadrupole interaction mechanism is significantly demonstrated by comparing experimental data with theoretical calculations. According to the concentration quenching-method, the critical distance of energy transfer from Bi(3+) to Eu(3+) is calculated to be 13.2 Å. As it is a new phosphor, CIE coordinates and CCT temperature, in addition to efficient energy transfer have been also investigated in detail. White light emission for MgY2Si3O10: n Bi(3+), m Eu(3+) can be realized through controlling the concentrations of Bi(3+) and Eu(3+). All of the results indicate that MgY2Si3O10: n Bi(3+), m Eu(3+) is a potential phosphor for white light UV-LEDs. PMID:25409734

Zhou, Hongpeng; Jin, Ye; Jiang, Mingsong; Wang, Qingping; Jiang, Xingxing

2015-01-21

315

Tracer Tests in a Fractured Dolomite: 3. Analysis of Mass Transfer in Single-Well Injection-Withdrawal Tests  

SciTech Connect

We investigated multiple-rate diffusion as a possible explanation for observed behavior in a suite of single-well injection-withdrawal (SWIW) tests conducted in a fractured dolomite. We first investigated the ability of a conventional double-porosity model and a multirate diffusion model to explain the data. This revealed that the multirate diffusion hypothesis/model is most consistent with all available data, and is the only model to date that is capable of matching each of the recovery curves entirely. Second, we studied the sensitivity of the SWIW recovery curves to the distribution of diffusion rate coefficients and other parameters. We concluded that the SWIW test is very sensitive to the distribution of rate coefficients, but is relatively insensitive to other flow and transport parameters such as advective porosity and dispersivity. Third, we examined the significance of the constant double-log late-time slopes ({minus}2. 1 to {minus}2.8), which are present in several data sets. The observed late-time slopes are significantly different than would be predicted by either conventional double-porosity or single-porosity media, and are found to be a distinctive feature of multirate diffusion under SWIW test conditions. Fourth, we found that the estimated distributions of diffusion rate coefficients are very broad, with the distributions spanning a range of at least 3.6 to 5.7 orders of magnitude.

Haggerty, R.; Fleming, S.W.; Meigs, L.C.; McKenna, S.A.

1999-03-04

316

Synthesis, transfer printing, electrical and optical properties, and applications of materials composed of self-assembled, aligned single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Super growth of single-walled carbon nanotubes (SWNTs) has emerged as a unique method for synthesizing self-assembled, pristine, aligned SWNT materials composed of ultra-long (millimeter-long) nanotubes. This thesis focuses on novel routes of synthesizing such self-assembled SWNTs and the challenges that arise in integrating this material into next-generation applications. First of all, this work provides unique insight into growth termination of aligned SWNTs, emphasizing the mechanism that inhibits the growth of infinitely long nanotubes. Exhaustive real-time growth studies, combined with ex-situ and in-situ TEM characterization emphasizes that Ostwald ripening and subsurface diffusion of catalyst particles play a key role in growth termination. As a result, rational steps to solving this problem can enhance growth, and may ultimately lead to the meter or kilometer-long SWNTs that are necessary for a number of applications. In addition, other novel synthesis routes are discussed, such as the ability to form macroscopic fibrils of SWNTs, called "flying carpets" from 40 nm thick substrates, and the ability to achieve supergrowth of SWNTs that are controllably doped with nitrogen. In the latter case, molecular heterojunctions of doped and undoped sections in a single strand of ultralong SWNTs are demonstrated Secondly, as supergrowth is conducted on alumina coated SiO2 substrates, any applications will require that one can transfer the SWNTs to host surfaces with minimal processing. This work demonstrates a unique contact transfer route by which both patterned arrays of SWNTs, or homogenous SWNT carpets, can be transferred to any host surface. In the first case, the SWNTs are grown vertically aligned, and transferred in patterns of horizontally aligned SWNT. This transfer process relies on simple water-vapor etching of amorphous carbons at the catalyst following growth, and strong van der Waals adhesion of the high surface-area SWNT to host surfaces (gecko effect). Next, as the SWNTs produced in supergrowth are notably large in diameter (2-5 nm), this work provides the first characterization of these SWNTs using combined microscopy and infrared polarized absorption studies. Perfectly aligned SWNTs are transferred to infrared optical windows and mounted in a rotatable vacuum cell in which polarization dependent characterization is carried out. By modeling features observed in absorption to expected optical excitonic transition energies, diameter distributions are rapidly extracted. In addition, other concepts of optical characterization in ultra-long aligned SWNTs are explored. For example, the concept of using polarized near-IR characterization for such SWNT samples is inadequate to characterize the bulk alignment due to the mismatch of the excitation wavelength and the SWNT length. Therefore, comparing anisotropy in polarized near-IR Raman or absorption gives substantially different results than anisotropic electrical transport measurements. In addition to optical characterization, this work uniquely finds that the electrical transport properties of SWNTs is ultimately limited by SWNT-SWNT junctions. This is evident in temperature-dependent DC and AC conductivity measurements that emphasize localization-induced transport characteristics. A number of non-classical electrical transport features are observed that can simply be related to the sensitivity of electrical transport to SWNT-SWNT junctions. This means that despite the incredible electrical properties of individual SWNTs, it is necessary to focus on the growth and processing of ultra-long SWNTs in order to realistically make nanotube-based materials comparable in transport characteristics to conventional materials. Finally, this work concludes by demonstrating progress on the fabrication of new SWNT-based applications. First of all, a new type of solid-state supercapacitor material is fabricated where vertically aligned SWNT are coated with metal-oxide dielectric and counterelectrode layers to form efficient supercapacitors. This design benefits from the

Pint, Cary L.

317

Saturation of power transfer between two copropagating laser beams by ion-wave scattering in a single-species plasma  

SciTech Connect

Experiments show that power is transferred between two copropagating 351 nm laser beams crossing in an Al plasma when the frequency of the driven ion wave is shifted by a Mach 1 flow. The resonant amplification of a low-intensity ({<=}2.5x10{sup 14} W/cm{sup 2}) beam intersected by a high-intensity (7.0x10{sup 14} W/cm{sup 2}) pump beam is determined by comparing the transmitted beam power to that measured in experiments where the plasma flow direction is reversed and the ion wave is evidently detuned. The polarization of the amplified light is also observed to align to the pump polarization consistent with ion-wave scattering. The amplification is found to reduce with probe-beam intensity demonstrating a nonlinear saturation mechanism that is effective when the ion-wave damping is weak, which is modeled with a calculation including both the nonlinear ion-wave frequency shifts due to ion trapping and whole-beam pump depletion.

Kirkwood, R.K.; Williams, E.A.; Cohen, B.I.; Divol, L.; Dorr, M.R.; Hittinger, J.A.; Langdon, A.B.; Niemann, C.; Moody, J.; Suter, L.J.; Landen, O.L. [Lawrence Livermore National Laboratory, Mail Stop L-473, P.O. Box 808, Livermore, California 94551 (United States)

2005-11-15

318

Solar radiative transfer in cirrus clouds. I - Single-scattering and optical properties of hexagonal ice crystals. II - Theory and computations of multiple scattering in an anisotropic medium  

NASA Technical Reports Server (NTRS)

The light scattering and absorption programs of Cai and Liou (1982) and Takano and Jaweera (1985) are extended to include hexagonal ice crystals randomly and horizontally oriented in space. The scattering and polarization results for the ice crystals are calculated. The results are compared with measurement data. The single-scattering properties for horizontally oriented columns and plates are presented and used to explain halos and arcs observed in the atmopshere. In the second section, the theory and computations for multiple scattering in cirrus clouds containing oriented ice crystals are presented. The radiative transfer in clouds composed of horizontally oriented ice crystals is formulated. Also, reflected and transmitted intensities, planetary albedo, and polarization in multiple scattering by ice crystals are discussed.

Takano, Yoshihide; Liou, Kuo-Nan

1989-01-01

319

Expression of transduced genes in mice generated by infecting blastocysts with avian leukosis virus-based retroviral vectors.  

PubMed Central

Transgenic mouse lines have been developed that express the tv-a receptor under the control of the chicken beta-actin promoter. These mice express the tv-a receptor in most or all tissues and in the early embryo. An avian leukosis virus (ALV)-based retroviral vector system was used for the efficient delivery of genes into preimplantation mouse embryos from these transgenic lines. Experimental animals could be generated quickly and easily by infecting susceptible blastocysts with ALV-based retroviral vectors. Expression of the delivered genes was controlled by either the constitutive viral promoter contained in the long terminal repeat or an internal nonviral tissue-specific promoter. Mating the infected founder chimeric animals produced animals that carry the ALV provirus as a transgene. A subset of the integrated proviruses expressed the chloramphenicol acetyltransferase reporter gene from either the promoter in the long terminal repeat or an internal promoter, which we believe indicates that many of the sites that are accessible to viral DNA insertion in preimplantation embryos are incompatible with expression in older animals. This approach should prove useful for studies on murine cell lineage and development, providing models for studying oncogenesis, and testing gene therapy strategies. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8643506

Federspiel, M J; Swing, D A; Eagleson, B; Reid, S W; Hughes, S H

1996-01-01

320

Cell colony formation induced by Xenopus egg extract as a marker for improvement of cloned blastocyst formation in the pig.  

PubMed

Treatment with cytoplasmic extracts from Xenopus laevis eggs represents a potential tool for universal cellular reprogramming. However, the biochemical activity and quality of the extract vary from batch to batch. This study aimed to evaluate three different extract batches prepared by the same method based on the colony formation of cells after extract treatment, and subsequent in vitro cloning efficiency using treated cells as chromatin donors. Porcine fetal fibroblasts were treated with each batch of extract, and cultured in embryonic stem cell (ES) medium for 12 days. The number of forming colonies in treated cells was counted on Day 7 after extract treatment and significant variability was detected between different batches of extract. Similarly, when using cells from colonies at Days 7 to 8 after treatment for handmade cloning, increased blastocyst formation rates were observed after the cells were treated with a batch showing higher colony formation. In conclusion, assessment of cell colony formation may be used as selection marker for Xenopus egg extract used for pretreatment of donor cells prior to cloning. PMID:22043808

Liu, Ying; Østrup, Olga; Li, Juan; Vajta, Gábor; Kragh, Peter M; Purup, Stig; Callesen, Henrik

2011-12-01

321

Qualitative estimation of the single-electron transfer step energetics mediated by samarium(II) complexes: a "SOMO-LUMO gap" approach.  

PubMed

Lanthanide II organometallic complexes usually initiate reactions via a single-electron transfer (SET) from the metal to a bonded substrate. Extensive mechanistic studies were carried out for lanthanide III complexes in which no change of oxidation state is involved. Some case-dependent strategies were reported by our group in order to account for a SET event in organometallic computed studies. In the present study, we show that analysis of DFT orbital spectra allows differentiating between exothermic and endothermic electron transfer. This methodology appears to be general; it allows differentiating between lanthanide centers and substituent effects on metallocenes. For that purpose, we considered mainly various samarocene adducts as well as a SmI2 complex explicitly solvated by THF. Comparison between DFT methods and ab initio (CAS-SCF and HF) computational level revealed that the SOMO-LUMO gap computed at the DFT B3PW91 level, in combination with small-core RECPs and standard basis sets, offers a qualitative estimation of the energetics of the SET that is in line with both CAS-SCF calculations and experimental results when available. This orbital-based approach, based on DFT calculation, affords a fast and efficient methodology for pioneer exploration of the reactivity of lanthanide(II) mediated by SET. PMID:24620762

Kefalidis, Christos E; Essafi, Stéphanie; Perrin, Lionel; Maron, Laurent

2014-04-01

322

A beta-(1-->3)-arabinopyranosyltransferase that transfers a single arabinopyranose onto arabino-oligosaccharides in mung bean (Vigna radiate) hypocotyls.  

PubMed

Arabinopyranosyltransferase (ArapT) activity that results in the transfer of a single arabinopyranose (Arap) residue from UDP-beta-L-arabinopyranose (UDP-Arap) to exogenous (1-->5)-linked alpha-L-arabino-oligosaccharides labeled with 2-aminobenzamide (2-AB) at their reducing ends was identified in a particulate preparation obtained from 3-day-old mung bean (Vigna radiate L. Wilezek) hypocotyls. The transferred Ara residue was shown to be beta-(1-->3)-linked to O-3 of the non-reducing terminal Araf residues of the oligosaccharide using nuclear magnetic resonance spectroscopy together with glycosyl composition and glycosyl linkage composition analyses. The 2AB-labeled arabino-octasaccharide was the most effective acceptor substrate analyzed, although arabino-oligosaccharides with a degree of polymerization between 4 and 7 were also acceptor substrates. Maximum ArapT activity was obtained at pH 6.5-7.0, and 20 degrees C in the presence of 25 mM Mn(2+) and 0.5% Triton X-100. PMID:16171834

Ishii, Tadashi; Konishi, Teruko; Ito, Yuki; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Maeda, Ikuko

2005-10-01

323

Rapid charge-transfer in polypyrrole-single wall carbon nanotube complex counter electrodes: Improved photovoltaic performances of dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, high efficiency, good durability, and easy fabrication. However, enhancement of power conversion efficiency and high cost of Pt counter electrode are still significant issues in commercial application of DSSCs. Herein, pyrrole-single wall nanotube (pyrrole-SWCNT) complexes are pioneerly synthesized by a reflux technique and subsequently in-situ polymerized and employed as counter electrodes (CEs) for DSSCs. Different from traditional polypyrrole/SWCNT (PPy/SWCNT) composites, the resultant PPy-SWCNT complexes are expected to fulfill the good electrical-conduction of SWCNT and electrocatalytic behaviors of PPy in accelerating electrochemical activity and charge transfer owing to the covalent bond between PPy (N atoms) and SWCNT (C atoms). The DSSCs employing PPy-SWCNT complex CEs exhibit significantly enhanced photovoltaic performances, in which a promising power conversion efficiency of 8.30% is obtained from PPy-2 wt‰ SWCNT complex CE in comparison with 6.31% from PPy-only CE. The high conversion efficiency, rapid charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PPy-SWCNT complexes in robust DSSCs.

He, Benlin; Tang, Qunwei; Luo, Jinghuan; Li, Qinghua; Chen, Xiaoxu; Cai, Hongyuan

2014-06-01

324

Excitation energy transfer in natural photosynthetic complexes and chlorophyll trefoils: hole-burning and single complex/trefoil spectroscopic studies  

SciTech Connect

In this project we studied both natural photosynthetic antenna complexes and various artificial systems (e.g. chlorophyll (Chl) trefoils) using high resolution hole-burning (HB) spectroscopy and excitonic calculations. Results obtained provided more insight into the electronic (excitonic) structure, inhomogeneity, electron-phonon coupling strength, vibrational frequencies, and excitation energy (or electron) transfer (EET) processes in several antennas and reaction centers. For example, our recent work provided important constraints and parameters for more advanced excitonic calculations of CP43, CP47, and PSII core complexes. Improved theoretical description of HB spectra for various model systems offers new insight into the excitonic structure and composition of low-energy absorption traps in very several antenna protein complexes and reaction centers. We anticipate that better understanding of HB spectra obtained for various photosynthetic complexes and their simultaneous fits with other optical spectra (i.e. absorption, emission, and circular dichroism spectra) provides more insight into the underlying electronic structures of these important biological systems. Our recent progress provides a necessary framework for probing the electronic structure of these systems via Hole Burning Spectroscopy. For example, we have shown that the theoretical description of non-resonant holes is more restrictive (in terms of possible site energies) than those of absorption and emission spectra. We have demonstrated that simultaneous description of linear optical spectra along with HB spectra provides more realistic site energies. We have also developed new algorithms to describe both nonresonant and resonant hole-burn spectra using more advanced Redfield theory. Simultaneous description of various optical spectra for complex biological system, e.g. artificial antenna systems, FMO protein complexes, water soluble protein complexes, and various mutants of reaction centers continues; this work is supported by the new DOE BES grant.

Ryszard Jankowiak, Kansas State University, Department of Chemistry, CBC Bldg., Manhattan KS, 66505; Phone: (785) 532-6785

2012-09-12

325

Superovulation and embryo transfer in wood bison (Bison bison athabascae).  

PubMed

Two experiments were done to develop an effective superovulatory treatment protocol in wood bison for the purpose of embryo collection and transfer. In experiment 1, donor bison were assigned randomly to four treatment groups (N = 5 per group) to examine the effects of method of synchronization (follicular ablation vs. estradiol-progesterone treatment) and ovarian follicular superstimulation (single slow-release vs. split dose of FSH). Recipient bison were synchronized with donor bison by either follicular ablation (N = 8) or estradiol-progesterone treatment (N = 9). In experiment 2, bison were assigned randomly to four treatment groups (N = 5 per group) to examine the ovarian response to two versus four doses of FSH, and the effect of progesterone (ovarian superstimulation with or without an intravaginal progesterone-releasing device). Donor bison were inseminated with fresh chilled wood bison semen 12 and 24 hours after treatment with GnRH (experiment 1) or LH (experiment 2). The ovarian response was assessed using ultrasonography. In experiment 1, the number of large follicles (? 7 mm) increased in response to both FSH treatments, but the diameter of the largest follicle detected 4 and 5 days after the start of ovarian superstimulation was greater in bison treated with a single dose of FSH than in those treated with two doses (P < 0.05). A total of 10 ova and/or embryos were collected. One blastocyst was transferred to each of five recipient bison resulting in the birth of two live wood bison calves. In experiment 2, two doses of FSH resulted in a greater number of large follicles (? 9 mm) on Days 4, 5, and 6 (P < 0.05) after beginning of superstimulation (Day 0), and more ovulations than four doses of FSH (11.2 ± 2.4 vs. 6.4 ± 0.8; P < 0.05). Embryo collection was performed on only five donors, and a total of 19 ova and/or embryos were recovered. In summary, fewer FSH treatments were as good or better than multiple treatments, consistent with the notion that minimizing handling stress improves the superovulatory response in bison. Follicular ablation and estradiol plus progesterone treatment were effective for inducing ovarian synchronization in embryo donor and recipient bison, and an intravaginal progesterone-releasing device during superstimulatory treatment did not influence the superovulatory response or embryo collection. Delaying ovulation-inducing treatment (GnRH or LH) to 5 days after superstimulatory treatment resulted in a greater number of ovulations and improved embryo collection efficiency (experiment 2). Embryo collection and transfer resulted in live offspring from wild wood bison. PMID:23831114

Toosi, Behzad M; Tribulo, Andres; Lessard, Carl; Mastromonaco, Gabriela F; McCorkell, Robert B; Adams, Gregg P

2013-09-15

326

Single therapeutic and supratherapeutic doses of anacetrapib, a cholesteryl ester transfer protein inhibitor, do not prolong the QTcF interval in healthy volunteers.  

PubMed

Anacetrapib is a cholesteryl ester transfer protein inhibitor in Phase III development. This double-blind, double-dummy, randomized, placebo- and active-comparator-controlled, 4-period, balanced crossover study evaluated the effects of anacetrapib (100?mg and 800?mg) on QTcF interval in healthy subjects. QTcF measurements were made up to 24?h following administration of single doses of anacetrapib 100 or 800?mg, moxifloxacin 400?mg, or placebo in the fed state. The primary hypothesis was supported if the 90% CI for the least squares (LS) mean differences between anacetrapib 800?mg and placebo in QTcF interval change from baseline were entirely <10 msec at every post-dose time point (1, 2, 2.5, 3, 4, 5, 6, 8, 12, and 24?h). The upper bounds of the 90% CIs for LS mean differences from placebo in changes from baseline in QTcF intervals for anacetrapib 100 and 800?mg were <5 msec at every time point. In conclusion, single doses of anacetrapib 100 and 800?mg do not prolong the QTcF interval to a clinically meaningful degree relative to placebo and are generally well tolerated in healthy subjects. PMID:24615657

Lauring, Brett; Liu, Yang; Li, Xiujiang Susie; Larson, Patrick; Moreau, Allison; Farmer, H Frank; Johnson-Levonas, Amy O; Wagner, John A; Lai, Eseng

2014-07-01

327

Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area  

SciTech Connect

Single-well injection-withdrawal (SWIW) tracer tests involve injection of traced fluid and subsequent tracer recovery from the same well, usually with some quiescent time between the injection and withdrawal periods. SWIW are insensitive to variations in advective processes that arise from formation heterogeneities, because upon withdrawal, fluid parcels tend to retrace the paths taken during injection. However, SWIW are sensitive to diffusive processes, such as diffusive exchange of conservative or reactive solutes between fractures and rock matrix. This paper focuses on SWIW tests in which temperature itself is used as a tracer. Numerical simulations demonstrate the sensitivity of temperature returns to fracture-matrix interaction. We consider thermal SWIW response to the two primary reservoir improvements targeted with stimulation, (1) making additional fractures accessible to injected fluids, and (2) increasing the aperture and permeability of pre-existing fractures. It is found that temperature returns in SWIW tests are insensitive to (2), while providing a strong signal of more rapid temperature recovery during the withdrawal phase for (1).

Pruess, K.; Doughty, C.

2010-01-15

328

Live embryo imaging to follow cell cycle and chromosomes stability after nuclear transfer.  

PubMed

Nuclear transfer (NT) into mouse oocytes yields a transcriptionally and functionally heterogeneous population of cloned embryos. Most studies of NT embryos consider only embryos at predefined key stages (e.g., morula or blastocyst), that is, after the bulk of reprogramming has taken place. These retrospective approaches are of limited use to elucidate mechanisms of reprogramming and to predict developmental success. Observing cloned embryo development using live embryo cinematography has the potential to reveal otherwise undetectable embryo features. However, light exposure necessary for live cell cinematography is highly toxic to cloned embryos. Here we describe a protocol for combined bright-field and fluorescence live-cell imaging of histone H2b-GFP expressing mouse embryos, to record cell divisions up to the blastocyst stage. This protocol, which can be adapted to observe other reporters such as Oct4-GFP or Nanog-GFP, allowed us to quantitatively analyze cleavage kinetics of cloned embryos. PMID:25287344

Balbach, Sebastian T; Boiani, Michele

2015-01-01

329

Graphene: metal-etching-free direct delamination and transfer of single-layer graphene with a high degree of freedom (small 2/2015).  

PubMed

A novel transfer process with an elastomeric stamp is described on page 175 by S.-Y. Choi and co-workers. It includes the metal-etching free, direct delamination of graphene from a copper growth substrate and transfer to a flexible substrate. The capabilities of the developed transfer process, such as large-area transfer onto a flexible substrate, multi-layer stacking of graphene, and transfer onto a structured electrode surface are demonstrated. PMID:25580691

Yang, Sang Yoon; Oh, Joong Gun; Jung, Dae Yool; Choi, HongKyw; Yu, Chan Hak; Shin, Jongwoo; Choi, Choon-Gi; Cho, Byung Jin; Choi, Sung-Yool

2015-01-01

330

Effects of in-vitro or in-vivo matured ooplasm and spindle-chromosome complex on the development of spindle-transferred oocytes.  

PubMed

To study the effects of in-vitro matured ooplasm and spindle-chromosome complex (SCC) on the development of spindle-transferred oocytes, reciprocal spindle transfer was conducted between in-vivo and in-vitro matured oocytes. The reconstructed oocytes were divided into four groups according to their different ooplasm sources and SCC, artificially activated and cultured to the blastocyst stage. Oocyte survival, activation and embryo development after spindle transfer manipulation were compared between groups. Survival, activation, and cleavage rates of reconstructed oocytes after spindle transfer manipulation did not differ significantly among the four groups. The eight-cell stage embryo formation rates on day 3 and the blastocyst formation rate on day 6 were not significantly different between the in-vitro and in-vivo matured SCC groups when they were transplanted into in-vivo matured ooplasm. The rate of eight-cell stage embryo formation with in-vitro matured ooplasm was significantly lower (P < 0.05) than that of embryos with in-vivo matured ooplasm, and none of the embryos developed to the blastocyst stage. Therefore, SCC matured in vitro effectively supported the in-vitro development of reconstructed oocytes. Ooplasm matured in vitro, however, could not support the development of reconstructed oocytes, and may not be an appropriate source of ooplasm donation for spindle transfer. PMID:25444504

Ding, Chenhui; Li, Tao; Zeng, Yanhong; Hong, Pingping; Xu, Yanwen; Zhou, Canquan

2014-12-01

331

Sensitive efficiency of photoinduced electron transfer to band gaps of semiconductive single-walled carbon nanotubes with supramolecularly attached zinc porphyrin bearing pyrene glues.  

PubMed

Photoinduced electron transfer in self-assembled single-walled carbon nanotube (SWNT)/zinc porphyrin (ZnP) hybrids utilizing (7,6)- and (6,5)-enriched SWNTs has been investigated. Toward this, first, zinc porphyrin was covalently functionalized to possess four pyrene entities (ZnP(pyr)(4)). Exfoliation of the semiconducting nanotube bundles occurred due to pi-pi-type interactions with the pyrene and porphyrin entities in organic solvents. The nanohybrids thus formed were isolated and characterized by TEM, UV-visible-near-IR, and Raman spectroscopy. Free-energy calculations suggested the possibility of electron transfer in both the (7,6)- and (6,5)-possessing ZnP(pyr)(4)/SWNT nanohybrids. Accordingly, fluorescence studies revealed efficient quenching of the singlet excited state of ZnP in the nanohybrids, originating from the charge separation, as confirmed by observation of a ZnP pi-cation radical in transient absorption spectra. The rates of charge separation were found to be slightly higher for (7,6)-SWNT-derived hybrids compared to the (6,5)-SWNT-derived hybrids. Charge recombination revealed an opposite effect, indicating that the (7,6)-SWNTs are slightly better for charge stabilization compared to the (6,5)-SWNTs. The present nanohybrids were further utilized to photochemically reduce the hexyl viologen dication in the presence of a sacrificial electron donor in an electron-pooling experiment, offering additional proof for the occurrence of photoinduced charge separation and potential utilization of these materials in light-energy-harvesting applications. Finally, solar cells constructed using the ZnP/SWNT hybrids revealed higher efficiency for the ZnP(pyr)(4)/(7,6)-SWNT hybrid with narrower nanotube band gap compared with the ZnP(pyr)(4)/(6,5)-SWNT having a relatively wider band gap. PMID:20499875

Maligaspe, Eranda; Sandanayaka, Atula S D; Hasobe, Taku; Ito, Osamu; D'Souza, Francis

2010-06-16

332

Reduced heterogeneity of electron transfer into polycrystalline TiO{<_2} films: site specific kinetics revealed by single-particle spectroscopy.  

SciTech Connect

The presenting surface of TiO{sub 2} is one of the key factors that influence the photoinduced charge injection process from covalently bound chromophores. However, the dependence of electron transfer (ET) on TiO{sub 2} surface properties (structure, defects, and facets) remains poorly understood due to the difficulties of deconvoluting the signal from a multitude of surface binding sites in highly heterogeneous ET systems. In an effort to correlate TiO{sub 2} surface features with ET, we compare the photoinduced ET dynamics from single quantum dots (QDs) to polycrystalline TiO{sub 2} thin films (pc-TiO{sub 2}) grown by atomic layer deposition (ALD) with that of porous TiO{sub 2} nanoparticle films (np-TiO{sub 2}) by utilizing single-particle fluorescence spectroscopy. Unlike the broad distribution of ET rates (deduced from fluorescence lifetimes) on np-TiO{sub 2}, QDs on pc-TiO{sub 2} exhibit two narrowly distributed ET rates that we attribute to reduced site heterogeneity. Variable temperature pc-TiO{sub 2} annealing studies suggest that the double-peaked distribution of ET rates is related to TiO{sub 2} surface defects, where QDs undergo more rapid ET. Further modification of pc-TiO{sub 2} with a submonolayer of Al{sub 2}O{sub 3} enables the selective exclusion of the more rapid ET pathway. More generally, this study provides insight into the role of surface defects in photoinduced ET into crystalline semiconductor oxides.

Jin, S.; Martinson, A. B. F.; Wiederrecht, G. P. (Center for Nanoscale Materials); ( MSD); (Northwestern Univ.)

2012-01-01

333

Production of good-quality blastocyst embryos following IVF of ovine oocytes vitrified at the germinal vesicle stage using a cryoloop.  

PubMed

The cryopreservation of immature oocytes at the germinal vesicle (GV) stage would create an easily accessible, non-seasonal source of female gametes for research and reproduction. The present study investigated the ability of ovine oocytes vitrified at the GV stage using a cryoloop to be subsequently matured, fertilised and cultured in vitro to blastocyst-stage embryos. Selected cumulus-oocyte complexes obtained from mature ewes at the time of death were randomly divided into vitrified, toxicity and control groups. Following vitrification and warming, viable oocytes were matured in vitro for 24 h. Matured oocytes were either evaluated for nuclear maturation, spindle and chromosome configuration or fertilised and cultured in vitro for 7 days. No significant differences were observed in the frequencies of IVM (oocytes at the MII stage), oocytes with normal spindle and chromatin configuration and fertilised oocytes among the three groups. Cleavage at 24 and 48 h post insemination was significantly decreased (P<0.01) in vitrified oocytes. No significant differences were observed in the proportion of blastocyst development between vitrified and control groups (29.4% v. 45.1%, respectively). No significant differences were observed in total cell numbers, the number of apoptotic nuclei or the proportion of diploid embryos among the three groups. In conclusion, we report for the first time that ovine oocytes vitrified at the GV stage using a cryoloop have the ability to be matured, fertilised and subsequently developed in vitro to produce good-quality blastocyst embryos at frequencies comparable to those obtained using fresh oocytes. PMID:23336581

Moawad, Adel R; Zhu, Jie; Choi, Inchul; Amarnath, Dasari; Chen, Wenchao; Campbell, Keith H S

2013-01-01

334

Phosphatidylcholine and sphingomyelin profiles vary in Bos taurus indicus and Bos taurus taurus in vitro- and in vivo-produced blastocysts.  

PubMed

Lipid droplets, subspecies (Bos taurus indicus vs. Bos taurus taurus), and in vitro culture are known to influence cryopreservation of bovine embryos. Limited information is available regarding differences in membrane lipids in embryo, such as phosphatidylcholines (PC) and sphingomyelins (SM). The objective of the present study was to compare the profiles of several PC and SM species and relate this information to cytoplasmic lipid levels present in Nellore (B. taurus indicus) and Simmental (B. taurus taurus) blastocysts produced in vitro (IVP) or in vivo (ET). Simmental and IVP embryos had more cytoplasmic lipid content than Nellore and ET embryos (n = 30). Blastocysts were submitted to matrix-assisted laser desorption/ionization mass spectrometry. Differences in the PC profile were addressed by principal component analysis. The lipid species with PC (32:1) and PC (34:1) had higher ion abundances in Nellore embryos, whereas PC (34:2) was higher in Simmental embryos. IVP embryos had less abundant ions of PC (32:1), PC (34:2), and PC (36:5) compared to ET embryos. Moreover, ion abundance of PC (32:0) was higher in both Nellore and Simmental IVP embryos compared to ET embryos. Therefore, mass spectrometry profiles of PC and SM species significantly differ with regard to unsaturation level and carbon chain composition in bovine blastocysts due to subspecies and in vitro culture conditions. Because PC abundances of Nellore and Simmental embryos were distinct (34:1 vs. 34:2), as were those of IVP and ET embryos (32:0 vs. 36:5), they are potential markers of postcryopreservation embryonic survival. PMID:23053436

Sudano, Mateus J; Santos, Vanessa G; Tata, Alessandra; Ferreira, Christina R; Paschoal, Daniela M; Machado, Rui; Buratini, José; Eberlin, Marcos N; Landim-Alvarenga, Fernanda D C

2012-06-01

335

OSL and photo-transferred TL of quartz single crystals sensitized by high-dose of gamma-radiation and moderate heat-treatments.  

PubMed

This study investigates the optically stimulated luminescence (OSL) and the photo-transferred thermoluminescence (PTTL) signals in quartz single crystals showing a strong TL peak near 300°C after being sensitized by irradiation with 25kGy of gamma rays and heating at 400°C. Natural and sensitized samples were prepared from two crystals with different sensitivity levels in the 300°C TL region. Continuous-wave (CW) and linearly-modulated (LM) OSL signals were stimulated with blue light-emitting diodes during 40 and 1000s, respectively. Two components were isolated from the CW-OSL signals of sensitized samples. These components were clearly seen in LM-OSL measurements together with two long-term components. LM-OSL showed that the sensitization process considered in this study sensitized an ultrafast OSL component of these crystals. The similar behavior found for the thermal stabilities of OSL and TL signals and the dependence of these signals with sample origins suggested that the trapping site related to the ultrafast component is also related to the TL process of the sensitized peak. The PTTL signal induced by blue LEDs increased the intensity of the sensitized glow peak. On the other hand, a remarkable reduction in the intensity of this peak as a result of the accumulated effect of blue light exposure was clearly seen in both kinds of crystals. These results were explained by a mechanism of competition between optically unstable deep traps and trap levels responsible to the sensitized TL peak. PMID:25151496

Ferreira de Souza, Leonardo B; Guzzo, Pedro L; Khoury, Helen J

2014-12-01

336

Dendritic, transferable, strictly monolayer MoS2 flakes synthesized on SrTiO3 single crystals for efficient electrocatalytic applications.  

PubMed

Controllable synthesis of macroscopically uniform, high-quality monolayer MoS2 is crucial for harnessing its great potential in optoelectronics, electrocatalysis, and energy storage. To date, triangular MoS2 single crystals or their polycrystalline aggregates have been synthesized on insulating substrates of SiO2/Si, mica, sapphire, etc., via portable chemical vapor deposition methods. Herein, we report a controllable synthesis of dendritic, strictly monolayer MoS2 flakes possessing tunable degrees of fractal shape on a specific insulator, SrTiO3. Interestingly, the dendritic monolayer MoS2, characterized by abundant edges, can be transferred intact onto Au foil electrodes and serve as ideal electrocatalysts for hydrogen evolution reaction, reflected by a rather low Tafel slope of ?73 mV/decade among CVD-grown two-dimensional MoS2 flakes. In addition, we reveal that centimeter-scale uniform, strictly monolayer MoS2 films consisting of relatively compact domains can also be obtained, offering insights into promising applications such as flexible energy conversion/harvesting and optoelectronics. PMID:25033228

Zhang, Yu; Ji, Qingqing; Han, Gao-Feng; Ju, Jing; Shi, Jianping; Ma, Donglin; Sun, Jingyu; Zhang, Yanshuo; Li, Minjie; Lang, Xing-You; Zhang, Yanfeng; Liu, Zhongfan

2014-08-26

337

Self-assembled single-walled carbon nanotube:zinc-porphyrin hybrids through ammonium ion-crown ether interaction: construction and electron transfer.  

PubMed

An ammonium ion-crown ether interaction has been successfully used to construct porphyrin-single-walled carbon nanotube (SWNT) donor-acceptor hybrids. The [18]crown-6 to alkyl ammonium ion binding strategy resulted in porphyrin-SWNT nanohybrids that are stable and soluble in DMF. The porphyrin-SWNT hybrids were characterized by spectroscopic, TEM, and electrochemical techniques. Both steady-state and time-resolved emission studies revealed efficient quenching of the singlet excited state of the porphyrins and free-energy calculations suggested that electron-transfer quenching occurred. Nanosecond transient absorption spectral results supported the charge-separation quenching process. Charge-stabilization was also observed for the nanohybrids in which the lifetime of the radical ion pairs was around 100 ns. The present nanohybrids were also used to reduce the hexyl viologen dication (HV2+) and to oxidize 1-benzyl-1,4-dihydronicotinamide in solution in an electron-pooling experiment. Accumulation of the radical cation (HV.+) was observed in high yields, which provided additional proof for the occurrence of photoinduced charge separation. The present study demonstrates that a hydrogen-bonding motif is a successful self-assembly method to build SWNTs bearing donor-acceptor nanohybrids, which are useful for light-energy harvesting and photovoltaic applications. PMID:17625800

D'Souza, Francis; Chitta, Raghu; Sandanayaka, Atula S D; Subbaiyan, Navaneetha K; D'Souza, Lawrence; Araki, Yasuyuki; Ito, Osamu

2007-01-01

338

Live Birth Sex Ratio after In Vitro Fertilization and Embryo Transfer in China - An Analysis of 121,247 Babies from 18 Centers  

PubMed Central

In order to study the impact of procedures of IVF/ICSI technology on sex ratio in China, we conducted this multi-center retrospective study including 121,247 babies born to 93,895 women in China. There were 62,700 male babies and 58,477 female babies, making the sex ratio being 51.8% (Male: Female ?=?107?100). In univariate logistic regression analysis, sex ratio was imbalance toward females of 50.3% when ICSI was preformed compared to 47.7% when IVF was used (P<0.01). The sex ratio in IVF/ICSI babies was significantly higher toward males in transfers of blastocyst (54.9%) and thawed embryo (52.4%) when compared with transfers of cleavage stage embryo (51.4%) and fresh embryo (51.5%), respectively. Multiple delivery was not associated with sex ratio. However, in multivariable logistic regression analysis after controlling for related factors, only ICSI (adjusted OR?=?0.90, 95%CI: 0.88–0.93; P<0.01) and blastocyst transfer (adjusted OR?=?1.14, 95% CI: 1.09–1.20; P<0.01) were associated with sex ratio in IVF/ICSI babies. In conclusion, the live birth sex ratio in IVF/ICSI babies was influenced by the use of ICSI, which may decrease the percentage of male offspring, or the use of blastocyst transfer, which may increase the percentage of male offspring. PMID:25412419

Bu, Zhiqin; Chen, Zi-Jiang; Huang, Guoning; Zhang, Hanwang; Sun, Haixiang; Sun, Yingpu

2014-01-01

339

Transfer form  

Cancer.gov

10/02 Transfer Investigational Agent Form This form is to be used for an intra-institutional transfer, one transfer/form. Division of Cancer Prevention National Cancer Institute National Institutes of Health TRANSFER FROM: Investigator transferring agent:

340

[Identification of nm23-M2/NDPK B expression during the blastocyst adhesiveness in the mouse endomerium by two-dimentional electrophoresis and MALDI-TOF-MASS spectrometry].  

PubMed

The nm23 gene family was involved in cellular multiphysiopathological processes including differentiation, development, apoptosis and cancer promotion, progression or metastasis. Some data indicate that nm23 plays an important role in regulating reproductive processes. In the present study, we analyzed the proteome of the implantation sites and the peri-implantation sites in NIH. mice on Day 5 of gestation by using two-Dimensional gel electrophoresis (2-D PAGE), while the virgin mice as the control. A protein spot with pI 7.1, Mr 18 kDa showed up-regulated expression in endometrium during the blastocysts adhesiveness. Using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), this protein was identified as nm23-M2/NDPK B. The nm23-M2 expression in mice endometrium was shown progressive increase on Day 5 of gestation by RT-PCR, which was consistent with the result obtained by immunohistochemistry. These findings suggest that nm23-M2/NDPK B was involved in the process of blastocyst implantation. PMID:16011243

Pan, Wei; Wang, Ying Xiong; Li, Gang; Weng, Ya Guang; Liu, Fang; Yu, Qui Bo

2005-04-01

341

Selection of reference genes for quantitative real-time PCR in equine in vivo and fresh and frozen-thawed in vitro blastocysts  

PubMed Central

Background Application of reverse transcription quantitative real-time polymerase chain reaction is very well suited to reveal differences in gene expression between in vivo and in vitro produced embryos. Ultimately, this may lead to optimized equine assisted reproductive techniques. However, for a correct interpretation of the real-time PCR results, all data must be normalized, which is most reliably achieved by calculating the geometric mean of the most stable reference genes. In this study a set of reliable reference genes was identified for equine in vivo and fresh and frozen-thawed in vitro embryos. Findings The expression stability of 8 candidate reference genes (ACTB, GAPDH, H2A/I, HPRT1, RPL32, SDHA, TUBA4A, UBC) was determined in 3 populations of equine blastocysts (fresh in vivo, fresh and frozen-thawed in vitro embryos). Application of geNorm indicated UBC, GAPDH, ACTB and HPRT1 as the most stable genes in the in vivo embryos and UBC, RPL32, GAPDH and ACTB in both in vitro populations. When in vivo and in vitro embryos were combined, UBC, ACTB, RPL32 and GAPDH were found to be the most stable. SDHA and H2A/I appeared to be highly regulated. Conclusions Based on these results, the geometric mean of UBC, ACTB, RPL32 and GAPDH is to be recommended for accurate normalization of quantitative real-time PCR data in equine in vivo and in vitro produced blastocysts. PMID:20003356

2009-01-01

342

Enhancing effects of serum-rich and cytokine-supplemented culture conditions on developing blastocysts and deriving porcine parthenogenetic embryonic stem cells  

PubMed Central

The present study was conducted to develop an effective method for establishment of porcine parthenogenetic embryonic stem cells (ppESCs) from parthenogenetically activated oocyte-derived blastocysts. The addition of 10% fetal bovine serum (FBS) to the medium on the 3rd day of oocyte culturing improved the development of blastocysts, attachment of inner cell masses (ICMs) onto feeder cells, and formation of primitive ppESC colonies. ICM attachment was further enhanced by basic fibroblast growth factor, stem cell factor, and leukemia inhibitory factor. From these attached ICMs, seven ppESC lines were established. ppESC pluripotency was verified by strong enzymatic alkaline phosphatase activity and the expression of pluripotent markers OCT3/4, Nanog, and SSEA4. Moreover, the ppESCs were induced to form an embryoid body and teratoma. Differentiation into three germ layers (ectoderm, mesoderm, and endoderm) was confirmed by the expression of specific markers for the layers and histological analysis. In conclusion, data from the present study suggested that our modified culture conditions using FBS and cytokines are highly useful for improving the generation of pluripotent ppESCs. PMID:24962410

Jung, Soo-Kyung; Kim, Hyun-Jung; Kim, Chan-Lan; Lee, Joo-Hyeong; You, Jin-Young; Lee, Eun-Song; Lim, Jeong-Mook; Yun, Seon Jong; Song, Jae-Young

2014-01-01

343

Enhancing effects of serum-rich and cytokine-supplemented culture conditions on developing blastocysts and deriving porcine parthenogenetic embryonic stem cells.  

PubMed

The present study was conducted to develop an effective method for establishment of porcine parthenogenetic embryonic stem cells (ppESCs) from parthenogenetically activated oocyte-derived blastocysts. The addition of 10% fetal bovine serum (FBS) to the medium on the 3rd day of oocyte culturing improved the development of blastocysts, attachment of inner cell masses (ICMs) onto feeder cells, and formation of primitive ppESC colonies. ICM attachment was further enhanced by basic fibroblast growth factor, stem cell factor, and leukemia inhibitory factor. From these attached ICMs, seven ppESC lines were established. ppESC pluripotency was verified by strong enzymatic alkaline phosphatase activity and the expression of pluripotent markers OCT3/4, Nanog, and SSEA4. Moreover, the ppESCs were induced to form an embryoid body and teratoma. Differentiation into three germ layers (ectoderm, mesoderm, and endoderm) was confirmed by the expression of specific markers for the layers and histological analysis. In conclusion, data from the present study suggested that our modified culture conditions using FBS and cytokines are highly useful for improving the generation of pluripotent ppESCs. PMID:24962410

Jung, Soo-Kyung; Kim, Hyun-Jung; Kim, Chan-Lan; Lee, Joo-Hyeong; You, Jin-Young; Lee, Eun-Song; Lim, Jeong-Mook; Yun, Seon Jong; Song, Jae-Young; Cha, Sang-Ho

2014-12-01

344

ICSI and day 5 embryo transfers: higher implantation rates and lower rate of multiple pregnancy with prolonged culture.  

PubMed

This retrospective review study, carried out in a private IVF clinic, compared pregnancy and implantation rates with day 3 versus day 5 embryo transfers in a selected group of patients. Participants were patients who failed to achieve pregnancy in at least one previous attempt with embryo transfer on days 2 or 3, and had more than five oocytes fertilized. A total of 296 patients who had undergone day 3 (group A) transfers were compared with 154 who had undergone day 5 transfers (group B). Interventions were intracytoplasmic sperm injection (ICSI), day 3 and day 5 embryo transfer. Outcome measures were pregnancy, implantation, multiple gestation and blastocyst formation rates. Overall, 86.4% of embryos were at the six- to eight-cell stage at 72 h and 30% developed to blastocyst by day 5. The mean number of embryos transferred was 4.0 on day 3 and 3.0 on day 5. Pregnancy and implantation rates were 34.8 and 11.5% in group A, versus 45.3 and 18.5% in group B. Multiple gestation rate was 47.1% in group A and 28.5% in group B. Prolonging embryo culture in vitro to day 5 improved embryo selection and implantation rates. A significant decrease in high order gestations was achieved by reducing the number of embryos transferred, without compromising the pregnancy rates. PMID:12513858

Abdelmassih, Vicente; Balmaceda, Jose P; Nagy, Zsolt P; Abdelmassih, Soraya; Abdelmassih, Roger

2001-01-01

345

Fabricating metal-oxide-semiconductor field-effect transistors on a polyethylene terephthalate substrate by applying low-temperature layer transfer of a single-crystalline silicon layer by meniscus force  

SciTech Connect

A low-temperature local-layer technique for transferring a single-crystalline silicon (c-Si) film by using a meniscus force was proposed, and an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) was fabricated on polyethylene terephthalate (PET) substrate. It was demonstrated that it is possible to transfer and form c-Si films in the required shape at the required position on PET substrates at extremely low temperatures by utilizing a meniscus force. The proposed technique for layer transfer was applied for fabricating high-performance c-Si MOSFETs on a PET substrate. The fabricated MOSFET showed a high on/off ratio of more than 10{sup 8} and a high field-effect mobility of 609 cm{sup 2} V{sup ?1} s{sup ?1}.

Sakaike, Kohei; Akazawa, Muneki; Nakamura, Shogo [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan)] [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan); Higashi, Seiichiro [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan) [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan); Research Institute for Nanodevice and Bio Systems, Hiroshima University, Kagamiyama 1-4-2, Higashihiroshima, Hiroshima 739-8527 (Japan)

2013-12-02

346

Prevention of multiple pregnancies in couples with unexplained or mild male subfertility: randomised controlled trial of in vitro fertilisation with single embryo transfer or in vitro fertilisation in modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation  

PubMed Central

Objectives To compare the effectiveness of in vitro fertilisation with single embryo transfer or in vitro fertilisation in a modified natural cycle with that of intrauterine insemination with controlled ovarian hyperstimulation in terms of a healthy child. Design Multicentre, open label, three arm, parallel group, randomised controlled non-inferiority trial. Setting 17 centres in the Netherlands. Participants Couples seeking fertility treatment after at least 12 months of unprotected intercourse, with the female partner aged between 18 and 38 years, an unfavourable prognosis for natural conception, and a diagnosis of unexplained or mild male subfertility. Interventions Three cycles of in vitro fertilisation with single embryo transfer (plus subsequent cryocycles), six cycles of in vitro fertilisation in a modified natural cycle, or six cycles of intrauterine insemination with ovarian hyperstimulation within 12 months after randomisation. Main outcome measures The primary outcome was birth of a healthy child resulting from a singleton pregnancy conceived within 12 months after randomisation. Secondary outcomes were live birth, clinical pregnancy, ongoing pregnancy, multiple pregnancy, time to pregnancy, complications of pregnancy, and neonatal morbidity and mortality Results 602 couples were randomly assigned between January 2009 and February 2012; 201 were allocated to in vitro fertilisation with single embryo transfer, 194 to in vitro fertilisation in a modified natural cycle, and 207 to intrauterine insemination with controlled ovarian hyperstimulation. Birth of a healthy child occurred in 104 (52%) couples in the in vitro fertilisation with single embryo transfer group, 83 (43%) in the in vitro fertilisation in a modified natural cycle group, and 97 (47%) in the intrauterine insemination with controlled ovarian hyperstimulation group. This corresponds to a risk, relative to intrauterine insemination with ovarian hyperstimulation, of 1.10 (95% confidence interval 0.91 to 1.34) for in vitro fertilisation with single embryo transfer and 0.91 (0.73 to 1.14) for in vitro fertilisation in a modified natural cycle. These 95% confidence intervals do not extend below the predefined threshold of 0.69 for inferiority. Multiple pregnancy rates per ongoing pregnancy were 6% (7/121) after in vitro fertilisation with single embryo transfer, 5% (5/102) after in vitro fertilisation in a modified natural cycle, and 7% (8/119) after intrauterine insemination with ovarian hyperstimulation (one sided P=0.52 for in vitro fertilisation with single embryo transfer compared with intrauterine insemination with ovarian hyperstimulation; one sided P=0.33 for in vitro fertilisation in a modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation). Conclusions In vitro fertilisation with single embryo transfer and in vitro fertilisation in a modified natural cycle were non-inferior to intrauterine insemination with controlled ovarian hyperstimulation in terms of the birth of a healthy child and showed comparable, low multiple pregnancy rates. Trial registration Current Controlled Trials ISRCTN52843371; Nederlands Trial Register NTR939. PMID:25576320

Bensdorp, A J; Tjon-Kon-Fat, R I; Bossuyt, P M M; Koks, C A M; Oosterhuis, G J E; Hoek, A; Hompes, P G A; Broekmans, F J M; Verhoeve, H R; de Bruin, J P; van Golde, R; Repping, S; Cohlen, B J; Lambers, M D A; van Bommel, P F; Slappendel, E; Perquin, D; Smeenk, J M; Pelinck, M J; Gianotten, J; Hoozemans, D A; Maas, J W M; Eijkemans, M J C; van der Veen, F; Mol, B W J

2015-01-01

347

Embryo transfer and embryonic capsules in the bobcat (Lynx rufus).  

PubMed

Bobcats (Lynx rufus) (n=22) were used to test a surgical embryo transfer protocol for wild felines. Five blastocysts were collected 8-14 days post-initial copulation (PIC). Translucent capsule-like structures were recovered at 12 days PIC and are the first report of such a structure in a felid. Endometrial fibrosis was observed in one cat but, in general, post-surgical fibrosis of the uterus did not seem to impede ova or embryo transport. One embryo underwent cryopreservation and this embryo plus two other transferrable embryos were placed in recipient cats during the course of the study. No pregnancies were maintained; but one non-cryopreserved embryo was detected by ultrasound examination at 2 weeks post-transfer. This study provides valuable groundwork for future studies and warrants optimism for continued research in this area. PMID:12047248

Miller, D L; Waldhalm, S J; Leopold, B D; Estill, C

2002-04-01

348

Study of turbulent single-phase heat transfer and onset of nucleate boiling in high aspect ratio mini-channels to support the MITR LEU conversion/  

E-print Network

Heat transfer in high aspect ratio mini-channels has important applications for materials test reactors using plate-type fuel. These fuel plates typically possess coolant channels with hydraulic diameters on the order of ...

Forrest, Eric Christopher

2014-01-01

349

1 pathways and cellular functions influenced by insulin treatment during oocyte maturation - a transcriptome study of in vitro-produced bovine day 8 blastocysts.  

PubMed

Insulin as a key metabolic hormone has crucial functions in metabolic regulation in all mammals. Deviation of its physiological concentration occurs in metabolic disorders as obesity and diabetes in humans or negative energy balance and overfeeding in the cow. As these metabolic disorders are strongly correlated with reproductive disturbances, we investigated the effect of insulin during oocyte maturation on gene expression of bovine Day 8 blastocysts (BC8) by transcriptome analysis. Abattoir-derived oocytes (n=882) were divided into 3 groups and in vitro matured for 22h by adding insulin (H: High 10µgmL(-1); L: Low 0.1µgmL(-1) and Z: Zero, control). This was followed by standard in vitro production (IVP) and evaluation of developmental rates up to blastocyst stage. BC8 (n=120) were pooled in groups of 10 and total RNA was extracted by parallel gDNA and total RNA-extraction (AllPrepDNA/RNA micro kit, cat no. 80284, Qiagen®, Valencia, CA, USA) for analyses of the transcriptome. All samples (4 biological replicates/group) resulted in RIN-values >7.5. RNA amplification, cDNA synthesis, purification, and labelling were performed and 825ng of Cy3- and Cy5-labelled linearly amplified aRNA was hybridized on the Agilent-manufactured EmbryoGENE-slides in a 2-colour dye swap design. An empirical Bayes moderated t-test was applied to search for the differentially expressed transcripts (DET) between control and insulin-treated groups, using the 'limma' package in R (www.r-project.org). The DET were defined as having a 1.5-fold change difference between treatment and control and P<0.05. Pathways and molecular functions influenced by insulin treatment were analysed by using Ingenuity Pathway Analysis (IPA; Ingenuity® Systems, www.ingenuity.com). As a global pattern, insulin treatment induced an up-regulation of genes. In total, 202 DET in the H and 142 DET in the L group were found where 104 DET were common in both insulin groups. Fifteen selected candidate genes chosen for qPCR validation and 12 (80%) showed similar expression patterns as the microarray data. DET relevant for following cellular functions were found in H: Cell Cycle, Cellular Compromise, Lipid Metabolism, Molecular Transport, Small Molecule Biochemistry respective L: Cell Morphology, Cellular Growth and Proliferation, Cell Cycle, Carbohydrate Metabolism and Cellular Assembly and Organization. The top canonical pathways influenced were Epithelial Adherens Junction Signalling and Remodelling, Germ Cell Sertoli Cell Junction Signalling and NRF2-mediated Oxidative Stress Response. Correlatively, blastocyst rates on Day 8 were significantly lower in H and L v. Z (P<0.05). The transcriptome data could explain the mechanisms behind the impaired development, as genes involved in cellular growth and energy metabolism in Day 8 blastocysts were affected. The fact that transcripts related to NRF2-mediated oxidative stress response and lipid metabolism are up-regulated suggests that insulin induces dysregulation of cellular functions and energy metabolism leading to impaired embryo developmental potential. PMID:25472050

Laskowski, D; Sjunnesson, Y; Båge, R; Sirard, M A; Gustafsson, H; Andersson, G; Humblot, P

2014-12-01

350

Transgenic Chicken, Mice, Cattle, and Pig Embryos by Somatic Cell Nuclear Transfer into Pig Oocytes  

PubMed Central

Abstract This study explored the possibility of producing transgenic cloned embryos by interspecies somatic cell nuclear transfer (iSCNT) of cattle, mice, and chicken donor cells into enucleated pig oocytes. Enhanced green florescent protein (EGFP)-expressing donor cells were used for the nuclear transfer. Results showed that the occurrence of first cleavage did not differ significantly when pig, cattle, mice, or chicken cells were used as donor nuclei (p>0.05). However, the rate of blastocyst formation was significantly higher in pig (14.9±2.1%; p<0.05) SCNT embryos than in cattle (6.3±2.5%), mice (4.2±1.4%), or chicken (5.1±2.4%) iSCNT embryos. The iSCNT embryos also contained a significantly less number of cells per blastocyst than those of SCNT pig embryos (p<0.05). All (100%) iSCNT embryos expressed the EGFP gene, as evidenced by the green florescence under ultraviolet (UV) illumination. Microinjection of purified mitochondria from cattle somatic cells into pig oocytes did not have any adverse effect on their postfertilization in vitro development and embryo quality (p>0.05). Moreover, NCSU23 medium, which was designed for in vitro culture of pig embryos, was able to support the in vitro development of cattle, mice, and chicken iSCNT embryos up to the blastocyst stage. Taken together, these data suggest that enucleated pig oocytes may be used as a universal cytoplast for production of transgenic cattle, mice, and chicken embryos by iSCNT. Furthermore, xenogenic transfer of mitochondria to the recipient cytoplast may not be the cause for poor embryonic development of cattle–pig iSCNT embryos. PMID:23808879

Gupta, Mukesh Kumar; Das, Ziban Chandra; Heo, Young Tae; Joo, Jin Young; Chung, Hak-Jae; Song, Hyuk; Kim, Jae-Hwan; Kim, Nam-Hyung; Lee, Hoon Taek; Ko, Dae Hwan

2013-01-01

351

Preimplantation development and expression of Hsp-70 and Bax genes in bovine blastocysts derived from oocytes matured in alpha-MEM supplemented with growth factors and synthetic macromolecules.  

PubMed

In vitro culture conditions affect both the maternal and embryonic expression of genes and is likely to alter both oocyte and embryo developmental competence. The search for better and less variable culture conditions simulating those in vivo has led to the development of defined culture media, with lower impact on the molecular reprogramming of oocytes and embryos. We evaluated embryo development and relative abundance (RA) of Hsp-70 and Bax transcripts in bovine blastocysts produced from oocytes matured in a chemically defined IVM system with synthetic polymers. Immature cumulus oocyte complexes (COCs) were matured for 22-24h in alpha-MEM supplemented with IGF-1, insulin, 0.1% polyvinyl alcohol (PVA), or 0.1% polyvinylpyrrolidone (PVP), but without FSH or LH. The control group consisted of COCs matured in TCM plus FSH and 10% estrous cow serum. After fertilization, presumptive zygotes were co-cultured with cumulus cells until 224 h post-insemination. Total RNA was isolated from embryo pools, reverse transcribed into cDNA, and subjected to transcript analysis by real-time PCR. Cleavage rate was higher (P<0.05) for the control group (68.3%) than for the PVA (54.4%) and PVP-40 (58.3%) groups. Nevertheless, there was no difference among the PVA, PVP-40 and control groups in blastocyst or hatching rates. Similarly, no difference in relative abundance of Hsp-70 and Bax transcripts was detected in comparison to the control group. We inferred that bovine oocytes can be matured in serum- and gonadotrophin-free medium supplemented with PVA or PVP, enriched with IGF-I and insulin, without altering post-cleavage development and relative abundance of some genes associated with stress and apoptosis. PMID:18962879

Vireque, A A; Camargo, L S A; Serapião, R V; Rosa E Silva, A A M; Watanabe, Y F; Ferreira, E M; Navarro, P A A S; Martins, W P; Ferriani, R A

2009-03-01

352

THE EFFECT OF PORCINE OVIDUCTAL FLUID ON IN VITRO DEVELOPMENT TO BLASTOCYST STAGE BY HOMOLOGOUS AND HETEROLOGOUS EMBRYOS  

Technology Transfer Automated Retrieval System (TEKTRAN)

In vitro fertilization rates for aspirated human oocytes are approximately 80 - 90%; however, implantation rates among these embryos are low, probably due to asynchronous transfers of cleavage stage embryos into the uterus. Improvement of in vitro culture conditions for the production of morulae/bl...

353

Comparison of the Interferon-tau Expression from Primary Trophectoderm Outgrowths Derived from IVP, NT, and Parthenogenote Bovine Blastocysts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine interferon-tau (IFN-tau) is the “maternal recognition of pregnancy” hormone produced by trophectoderm cells of the pre-implantation stage bovine embryo. The expression of IFN-tau is essential for bovine embryo survival in the uterus, and, because somatic cell nuclear transfer (NT) embryos ap...

354

Opine catabolism and conjugal transfer of the nopaline Ti plasmid pTiC58 are coordinately regulated by a single repressor.  

PubMed Central

The Ti plasmids of Agrobacterium tumefaciens are conjugal elements whose transfer is strongly repressed. Transfer is induced by the conjugal opines, a group of unique carbon compounds synthesized in crown gall tumors. The opines also induce Ti plasmid-encoded genes required by the bacteria for opine catabolism. We have cloned and sequenced a gene from the Ti plasmid pTiC58, whose product mediates the opine-dependent regulation of conjugal transfer and catabolism of the conjugal opines, agrocinopines A and B. The gene, accR, is closely linked to the agrocinopine catabolic locus. A spontaneous mutant Ti plasmid, pTiC58Trac, which constitutively expresses conjugal transfer and opine catabolism, was complemented in trans by a clone of wild-type accR. Comparative sequence analysis identified a 5-base-pair deletion close to the 5' end of the mutant accR allele from pTiC58Trac. Analysis of lacZ fusions in conjugal transfer and opine catabolic structural genes demonstrated that the accR-encoded function is a transcriptional repressor. accR can encode a 28-kDa protein. This protein is related to a class of repressor proteins that includes LacR, GutR, DeoR, FucR, and GlpR that regulate sugar catabolic systems in several bacterial genera. Images PMID:1731335

Beck von Bodman, S; Hayman, G T; Farrand, S K

1992-01-01

355

Benchmark full configuration interaction and equation-of-motion coupled-cluster model with single and double substitutions for ionized systems results for prototypical charge transfer systems: Noncovalent ionized dimers  

NASA Astrophysics Data System (ADS)

Benchmark full configuration interaction and equation-of-motion coupled-cluster model with single and double substitutions for ionized systems (EOM-IP-CCSD) results are presented for prototypical charge transfer species. EOM-IP-CCSD describes these doublet systems based on the closed-shell reference and thus avoids the doublet instability problem. The studied quantities are associated with the quality of the potential energy surface (PES) along the charge transfer coordinate and distribution of the charge between fragments. It is found that EOM-IP-CCSD is capable of describing accurately both the charge-localized and charge-delocalized systems, yielding accurate charge distributions and energies. This is in stark contrast with the methods based on the open-shell reference, which overlocalize the charge and produce a PES cusp when the fragments are indistinguishable.

Pieniazek, Piotr A.; Arnstein, Stephen A.; Bradforth, Stephen E.; Krylov, Anna I.; Sherrill, C. David

2007-10-01

356

Bacteroides fragilis Transfer Factor Tn5520: the Smallest Bacterial Mobilizable Transposon Containing Single Integrase and Mobilization Genes That Function in Escherichia coli  

PubMed Central

Many bacterial genera, including Bacteroides spp., harbor mobilizable transposons, a class of transfer factors that carry genes for conjugal DNA transfer and, in some cases, antibiotic resistance. Mobilizable transposons are capable of inserting into and mobilizing other, nontransferable plasmids and are implicated in the dissemination of antibiotic resistance. This paper presents the isolation and characterization of Tn5520, a new mobilizable transposon from Bacteroides fragilis LV23. At 4,692 bp, it is the smallest mobilizable transposon reported from any bacterial genus. Tn5520 was captured from B. fragilis LV23 by using the transfer-deficient shuttle vector pGAT400?BglII. The termini of Tn5520 contain a 22-bp imperfect inverted repeat, and transposition does not result in a target site repeat. Tn5520 also demonstrates insertion site sequence preferences characterized by A-T-rich nucleotide sequences. Tn5520 has been sequenced in its entirety, and two large open reading frames whose predicted protein products exhibit strong sequence similarity to recombinase-integrase enzymes and mobilization proteins, respectively, have been identified. The transfer, mobilization, and transposition properties of Tn5520 have been studied, revealing that Tn5520 mobilizes plasmids in both B. fragilis and Escherichia coli at high frequency and also transposes in E. coli. PMID:10198023

Vedantam, Gayatri; Novicki, Thomas J.; Hecht, David W.

1999-01-01

357

Heat transfer enhancement in single-phase forced convection with blockages and in two-phase pool boiling with nano-structured surfaces  

E-print Network

the average heat (mass) transfer by up to 8.5 and 7.0 times that for fully developed turbulent flow through a smooth channel at the same mass flow rate, respectively, in the smaller and larger hole-to-blockage area ratio (or smaller and larger hole diameter...

Ahn, Hee Seok

2007-09-17

358

Effects of pendant ligand binding affinity on chain transfer for 1-hexene polymerization catalyzed by single-site zirconium amine bis-phenolate complexes.  

PubMed

The kinetics of 1-hexene polymerization using a family of five zirconium amine bis-phenolate catalysts, Zr[tBu-ON(X)O]Bn2 (where X = THF (1), pyridine (2), NMe2 (3), furan (4), and SMe (5)), has been investigated to uncover the mechanistic effect of varying the pendant ligand X. A model-based approach using a diverse set of data including monomer consumption, evolution of molecular weight, and end-group analysis was employed to determine each of the reaction specific rate constants involved in a given polymerization process. The mechanism of polymerization for 1-5 was similar and the necessary elementary reaction steps included initiation, normal propagation, misinsertion, recovery from misinsertion, and chain transfer. The latter reaction, chain transfer, featured monomer independent ?-H elimination in 1-3 and monomer dependent ?-H transfer in 4 and 5. Of all the rate constants, those for chain transfer showed the most variation, spanning 2 orders of magnitude (ca. (0.1-10) × 10(-3) s(-1) for vinylidene and (0.5-87) × 10(-4) s(-1) for vinylene). A quantitative structure-activity relationship was uncovered between the logarithm of the chain transfer rate constants and the Zr-X bond distance for catalysts 1-3. However, this trend is broken once the Zr-X bond distance elongates further, as is the case for catalysts 4 and 5, which operate primarily through a different mechanistic pathway. These findings underscore the importance of comprehensive kinetic modeling using a diverse set of multiresponse data, enabling the determination of robust kinetic constants and reaction mechanisms of catalytic olefin polymerization as part of the development of structure-activity relationships. PMID:23517426

Steelman, D Keith; Xiong, Silei; Pletcher, Paul D; Smith, Erin; Switzer, Jeffrey M; Medvedev, Grigori A; Delgass, W Nicholas; Caruthers, James M; Abu-Omar, Mahdi M

2013-04-24

359

Three-day-old human unfertilized oocytes after in vitro fertilization/intracytoplasmic sperm injection can be activated by calcium ionophore a23187 or strontium chloride and develop to blastocysts.  

PubMed

Our objective was to observe the effectiveness of the calcium ionophore A23187 or strontium chloride on the activation and subsequent embryonic development of 3-day-old human unfertilized oocytes after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). A total of 279 3-day-old unfertilized oocytes after IVF or ICSI were randomized to be activated by the calcium ionophore A23187 (n=138) or strontium chloride (n=141). The activated oocytes were cultured in vitro for 3-5 days. Activation rate, pronucleus formation, cleavage rate, and developmental potential of parthenotes during culture were evaluated. A total of 170 unfertilized oocytes were activated; 65 developed to cleavage stage, 19 developed to greater than the eight-cell stage, and five blastocysts were obtained. The activation rate of the calcium ionophore A23187 group was higher than that of the strontium chloride group (75.4% and 46.8%, respectively; p<0.05); there was significant difference between two groups (p<0.05). Among the 44 cleaved oocytes in the calcium ionophore A23187 group, eight developed to the two- to four-cell stage, 17 developed to the five- to eight-cell stage, 15 developed to greater than the eight-cell stage, and four blastocysts were obtained. Among the 21 cleaved oocytes in the strontium chloride group, six developed to the two- to four- cell stage, 10 developed to the five- to eight-cell stage, four developed to greater than the eight-cell stage, and one blastocyst was obtained. Three-day-old unfertilized human oocytes after IVF or ICSI could be activated by the calcium ionophore A23187 or strontium chloride, and a small part of parthenogenetic embryos developed into blastocysts. The treatment with the calcium ionophore A23187 was better than that of strontium chloride in respect to the activation rate of 3-day-old unfertilized human oocytes after IVF or ICSI. PMID:24960285

Liu, Ying; Han, Xiao-Jie; Liu, Ming-Hui; Wang, Shu-Yu; Jia, Chan-Wei; Yu, Lan; Ren, Guoqing; Wang, Li; Li, Wei

2014-08-01

360

Neutron single-particle states above the N=164 subshell in {sub 98}{sup 251}Cf and {sub 96}{sup 249}Cm studied by neutron transfer reactions  

SciTech Connect

Single-particle state assignments in {sup 251}Cf and {sup 249}Cm at {approx}1 MeV excitation have been deduced from cross sections previously measured for the {sup 250}Cf(d,p){sup 251}Cf and {sup 248}Cm({sup 4}He,{sup 3}He){sup 249}Cm reactions. The assignments are supported by observed cross-section signatures and intraband level spacings. The observed energies of these single-particle states, after pairing effects are removed, are in good agreement with values calculated using a Woods-Saxon single-particle potential. Neutron level diagrams, showing level spacings as a function of {nu}{sub 2},{nu}{sub 4}, and {nu}{sub 6}, are extended to include neutron orbitals above N=164.

Ahmad, I.; Chasman, R. R. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2009-12-15

361

156 laparoscopic uterine embryo transfer in the cat.  

PubMed

In the first successful transfer of cat embryos (Theriogenology 11, 51-62), the uterus was accessed by midventral laparotomy. That surgical approach was the most widely used method for transferring cat embryos for more than two decades. Then, 10 to 15 years ago pregnancies were reported after early cleavage stage embryos were transferred to the oviduct of recipients using a laparoscopic technique. Even though laparoscopic oviducal embryo transfer has produced higher survival/pregnancy rates than were obtained previously there are valid reasons for establishing a minimally invasive, technically simple method for depositing morulae and blastocysts into the uterus of recipients. Thus, the purpose of the present project was to develop a technique for laparoscopic uterine embryo transfer in the cat. Recipients (n=4) were gonadotropin-treated females (Theriogenology 81, 126-37) from which prevoulatory oocytes (n=27-42/retrieval) had been recovered 7 or 8 days previously. The procedure for accessing the reproductive tract has been described (Theriogenology 71, 864-71). Briefly, after abdominal insufflation via a Veress needle, two 5-mm ports were inserted in the midline - one ~2.5cm anterior to the umbilicus and the other between the two most posterior teats. An endoscope/camera and a Babcock forceps were placed in the anterior and posterior ports, respectively. After the left uterine horn was stabilised with the Veress needle, the Babcock forceps were gently applied at ~2-3cm from the anterior tip. In the first two attempts, a 16 g×5cm thin-walled stainless steel (s.s.) trocar/cannula was inserted transabdominally such that it aligned with the anterior portion of the left uterine horn when elevated with the forceps. Then, either a 14-cm, 3.5 Fr tom cat catheter with a s.s. sharp-tipped stylette or a 20/22 g×6cm indwelling catheter was passed through the s.s. cannula and inserted into the uterine horn. In each case, the length of the s.s. cannula restricted depth of insertion of the catheter into the horn. Polyethylene tubing (PE10) containing the embryos was threaded through the catheter and embryos were expelled with a 1-mL threaded-plunger syringe. The failure to establish pregnancies after transfer of five or six Day 7 or Day 8 IVF-derived "fresh" embryos into the first two recipients was attributed to technical difficulties. So, for the third and fourth procedures, we shortened the s.s. trocar/cannula to 2.5cm and, for insertion into the horn, a 20/22 g×6cm indwelling catheter was used. With the third procedure, in which cryopreserved d 8 IVF blastocysts were transferred into a Day 7 recipient, the failure was possibility due sub-optimal in vitro development of embryos after thawing on d 7. For the fourth transfer, 6 "fresh" Day 8 IVF blastocysts - 2 expanding and 4 in the early stages of emerging from the zona pellucida - were auto-transferred into a 3-year-old recipient. A singleton pregnancy was diagnosed by ultrasonography on Day 28 and a live, healthy male kitten (119g) was born on Day 67. In summary, we demonstrated the feasibility of transferring in vitro-derived cat embryos into the uterus of recipients by the minimally invasive technique of laparoscopy. PMID:25472205

Pope, C E; Galiguis, J H; Dumas, C; Gómez, M C

2014-12-01

362

Nonsurgical Embryo Transfer Device Compared with Surgery for Embryo Transfer in Mice  

PubMed Central

The use of a murine nonsurgical embryo transfer (NSET) device had been described previously for the transfer of blastocysts, morulae, DNA-microinjected embryos, and embryonic stem cell-containing embryos to create genetically modified mice. However, physiologic effects of the NSET device and traditional surgical methods had not been compared directly. Here we used electrocardiography and fecal corticosterone levels to monitor pseudopregnant mice that underwent anesthesia only, the NSET procedure with or without anesthesia, or surgery. These procedures were performed without the use of actual embryos, to focus on effects of the procedures themselves rather than on any physiologic effects due to the deposition of embryos. As compared with surgery and anesthesia, the NSET procedure was associated with less fluctuation in cardiac rhythm and lower levels of the stress biomarker fecal corticosterone. These results indicate that use of the NSET device avoids these physiological perturbations as well as other disadvantages of surgery (for example, postoperative pain and need for postoperative analgesia) and therefore provides a valuable refinement of existing mouse embryo transfer procedures. PMID:23562028

Steele, Kendra H; Hester, James M; Stone, Barbara J; Carrico, Kimberly M; Spear, Brett T; Fath-Goodin, Angelika

2013-01-01

363

Exciton generation/dissociation/charge-transfer enhancement in inorganic/organic hybrid solar cells by robust single nanocrystalline LnPxOy (Ln = Eu, Y) doping.  

PubMed

Low-temperature solution-processed photovoltaics suffer from low efficiencies because of poor exciton or electron-hole transfer. Inorganic/organic hybrid solar cell, although still in its infancy, has attracted great interest thus far. One of the promising ways to enhance exciton dissociation or electron-hole transport is the doping of lanthanide phosphate ions. However, the underlying photophysical mechanism remains poorly understood. Herein, by applying femtosecond transient absorption spectroscopy, we successfully distinguished hot electron, less energetic electron, hole transport from electron-hole recombination. Concrete evidence has been provided that lanthanide phosphate doping improves the efficiency of both hot electron and "less energetic" electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 12.7 ps, that is, more than 60% faster than pure TiO2 acceptor. Such improvement was ascribed to the facts that the conduction band (CB) edge energy level of TiO2 has been elevated by 0.2 eV, while the valence band level almost remains unchanged, thus not only narrowing the energy offset between CB levels of TiO2 and P3HT, but also meanwhile enlarging the band gap of TiO2 itself that permits one to inhibit electron-hole recombination within TiO2. Consequently, lanthanide phosphate doped TiO2/P3HT bulk-heterojunction solar cell has been demonstrated to be a promising hybrid solar cell, and a notable power conversion efficiency of 2.91% is therefore attained. This work indicates that lanthanide compound ions can efficiently facilitate exciton generation, dissociation, and charge transport, thus enhancing photovoltaic performance. PMID:24835845

Jin, Xiao; Sun, Weifu; Chen, Zihan; Wei, Taihuei; Chen, Chuyang; He, Xingdao; Yuan, Yongbiao; Li, Yue; Li, Qinghua

2014-06-11

364

Microstructure and properties of single crystal BaTiO3 thin films synthesized by ion implantation-induced layer transfer  

E-print Network

extensively reported. Single crystal ferroelectric thin films can be used in applications such as actuator Institute of Physics. [DOI: 10.1063/1.1773373] Ferroelectric thin films have been widely explored, and have promise for high work/volume mechanical actuators in microelectromechanical systems (MEMS

Atwater, Harry

365

Important aspects of placental-specific gene transfer.  

PubMed

The placenta is a unique and highly complex organ that develops only during pregnancy and is essential for growth and survival of the developing fetus. The placenta provides the vital exchange of gases and wastes, the necessary nutrients for fetal development, acts as immune barrier that protects against maternal rejection, and produces numerous hormones and growth factors that promote fetal maturity to regulate pregnancy until parturition. Abnormal placental development is a major underlying cause of pregnancy-associated disorders that often result in preterm birth. Defects in placental stem cell propagation, growth, and differentiation are the major factors that affect embryonic and fetal well-being and dramatically increase the risk of pregnancy complications. Understanding the processes that regulate placentation is important in determining the underlying factors behind abnormal placental development. The ability to manipulate genes in a placenta-specific manner provides a unique tool to analyze development and eliminates potentially confounding results that can occur with traditional gene knockouts. Trophoblast stem cells and mouse embryos are not overly amenable to traditional gene transfer techniques. Most viral vectors, however, have a low infection rate and often lead to mosaic transgenesis. Although the traditional method of embryo transfer is intrauterine surgical implantation, the methodology reported here, combining lentiviral blastocyst infection and nonsurgical embryo transfer, leads to highly efficient and placental-specific gene transfer. Numerous advantages of our optimized procedures include increased investigator safety, a reduction in animal stress, rapid and noninvasive embryo transfer, and higher a rate of pregnancy and live birth. PMID:25110063

Kaufman, Melissa R; Albers, Renee E; Keoni, Chanel; Kulkarni-Datar, Kashmira; Natale, David R; Brown, Thomas L

2014-10-15

366

Effects of Multimodal Analgesia on the Success of Mouse Embryo Transfer Surgery  

PubMed Central

Multimodal analgesia is promoted as the best practice pain management for invasive animal research procedures. Universal acceptance and incorporation of multimodal analgesia requires assessing potential effects on study outcome. The focus of this study was to assess effects on embryo survival after multimodal analgesia comprising an opioid and nonsteroidal antiinflammatory drug (NSAID) compared with opioid-only analgesia during embryo transfer procedures in transgenic mouse production. Mice were assigned to receive either carprofen (5 mg/kg) with buprenorphine (0.1 mg/kg; CB) or vehicle with buprenorphine (0.1 mg/kg; VB) in a prospective, double-blinded placebo controlled clinical trial. Data were analyzed in surgical sets of 1 to 3 female mice receiving embryos chimeric for a shared targeted embryonic stem-cell clone and host blastocyst cells. A total of 99 surgical sets were analyzed, comprising 199 Crl:CD1 female mice and their 996 offspring. Neither yield (pups weaned per embryo implanted in the surgical set) nor birth rate (average number of pups weaned per dam in the set) differed significantly between the CB and VB conditions. Multimodal opioid–NSAID analgesia appears to have no significant positive or negative effect on the success of producing novel lines of transgenic mice by blastocyst transfer. PMID:21838973

Parker, John M.; Austin, Jamie; Wilkerson, James; Carbone, Larry

2011-01-01

367

Synthesis, transfer printing, electrical and optical properties, and applications of materials composed of self-assembled, aligned single-walled carbon nanotubes  

Microsoft Academic Search

Super growth of single-walled carbon nanotubes (SWNTs) has emerged as a unique method for synthesizing self-assembled, pristine, aligned SWNT materials composed of ultra-long (millimeter-long) nanotubes. This thesis focuses on novel routes of synthesizing such self-assembled SWNTs and the challenges that arise in integrating this material into next-generation applications. First of all, this work provides unique insight into growth termination of

Cary L. Pint

2010-01-01

368

Vitamin C enhances in vitro and in vivo development of porcine somatic cell nuclear transfer embryos  

SciTech Connect

Highlights: {yields} Report for the first time that vitamin C has a beneficial effect on the development of porcine SCNT embryos. {yields} The level of acH4K5 and Oct4 expression at blastocyst-stage was up-regulated after treatment. {yields} A higher rate of gestation and increased number of piglets born were harvested in the treated group. -- Abstract: The reprogramming of differentiated cells into a totipotent embryonic state through somatic cell nuclear transfer (SCNT) is still an inefficient process. Previous studies revealed that the generation of induced pluripotent stem (iPS) cells from mouse and human fibroblasts could be significantly enhanced with vitamin C treatment. Here, we investigated the effects of vitamin C, to our knowledge for the first time, on the in vitro and in vivo development of porcine SCNT embryos. The rate of blastocyst development in SCNT embryos treated with 50 {mu}g/mL vitamin C 15 h after activation (36.0%) was significantly higher than that of untreated SCNT embryos (11.5%). The enhanced in vitro development rate of vitamin C-treated embryos was associated with an increased acetylation level of histone H4 lysine 5 and higher Oct4, Sox2 and Klf4 expression levels in blastocysts, as determined by real-time PCR. In addition, treatment with vitamin C resulted in an increased pregnancy rate in pigs. These findings suggest that treatment with vitamin C is beneficial for enhancement of the in vitro and in vivo development of porcine SCNT embryos.

Huang, Yongye; Tang, Xiaochun; Xie, Wanhua; Zhou, Yan; Li, Dong; Zhou, Yang; Zhu, Jianguo; Yuan, Ting; Lai, Liangxue [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China)] [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China); Pang, Daxin, E-mail: pdx@jlu.edu.cn [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China)] [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China); Ouyang, Hongsheng, E-mail: ouyh@jlu.edu.cn [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China)] [Jilin Province Key Laboratory of Animal Embryo Engineering, College of Animal Science and Veterinary Medicine, Jilin University, 5333 Xi An DaLu, Changchun 130062 (China)

2011-07-29

369

Ovine induced pluripotent stem cells are resistant to reprogramming after nuclear transfer.  

PubMed

Induced pluripotent stem cells (iPSCs) share similar characteristics of indefinite in vitro growth with embryonic stem cells (ESCs) and may therefore serve as a useful tool for the targeted genetic modification of farm animals via nuclear transfer (NT). Derivation of stable ESC lines from farm animals has not been possible, therefore, it is important to determine whether iPSCs can be used as substitutes for ESCs in generating genetically modified cloned farm animals. We generated ovine iPSCs by conventional retroviral transduction using the four Yamanaka factors. These cells were basic fibroblast growth factor (bFGF)- and activin A-dependent, showed persistent expression of the transgenes, acquired chromosomal abnormalities, and failed to activate endogenous NANOG. Nonetheless, iPSCs could differentiate into the three somatic germ layers in vitro. Because cloning of farm animals is best achieved with diploid cells (G1/G0), we synchronized the iPSCs in G1 prior to NT. Despite the cell cycle synchronization, preimplantation development of iPSC-NT embryos was lower than with somatic cells (2% vs. 10% blastocysts, p<0.01). Furthermore, analysis of the blastocysts produced demonstrated persistent expression of the transgenes, aberrant expression of endogenous SOX2, and a failure to activate NANOG consistently. In contrast, gene expression in blastocysts produced with the parental fetal fibroblasts was similar to those generated by in vitro fertilization. Taken together, our data suggest that the persistent expression of the exogenous factors and the acquisition of chromosomal abnormalities are incompatible with normal development of NT embryos produced with iPSCs. PMID:25513856

German, Sergio D; Campbell, Keith H S; Thornton, Elisabeth; McLachlan, Gerry; Sweetman, Dylan; Alberio, Ramiro

2015-02-01

370

Transcriptional regulators TRIM28, SETDB1, and TP53 are aberrantly expressed in porcine embryos produced by in vitro fertilization in comparison to in vivo- and somatic-cell nuclear transfer-derived embryos  

PubMed Central

In vitro embryo production is important for research in animal reproduction, embryo transfer, transgenics, and cloning. Yet, in vitro-fertilized (IVF) embryos are generally developmentally delayed and are inferior to in vivo-derived (IVV) embryos; this discrepancy is likely a result of aberrant gene expression. Transcription of three genes implicated to be important in normal preimplantation embryo development, TRIM28, SETDB1, and TP53, was determined by quanitative PCR in IVF, somatic-cell nuclear transfer (SCNT), parthenogenetic, and IVV porcine oocytes and embryos. There was no difference in TRIM28 or SETDB1 abundance between oocytes matured in vitro versus in vivo (P > 0.05), whereas TP53 levels were higher in in vitro-matured oocytes. TRIM28 increased from metaphase-II oocytes to the 4-cell and blastocyst stages in IVF embryos, whereas IVV embryos showed a reduction in TRIM28 abundance from maturation throughout development. The relative abundance of TP53 increased by the blastocyst stage in all treatment groups, but was higher in IVF embryos compared to IVV and SCNT embryos. In contrast, SETDB1 transcript levels decreased from the 2-cell to blastocyst stage in all treatments. For each gene analyzed, SCNT embryos of both hard-to-clone and easy-to-clone cell lines were more comparable to IVV than IVF embryos. Knockdown of TRIM28 also had no effect on blastocyst development or expression of SETDB1 or TP53. Thus, TRIM28, SETDB1, and TP53 are dynamically expressed in porcine oocytes and embryos. Furthermore, TRIM28 and TP53 abundances in IVV and SCNT embryos are similar, but different from quantities in IVF embryos. Mol. Reprod. Dev. 81: 552–556, 2014. © 2014 The Authors. Published by Wiley Periodicals, Inc. PMID:24659575

Hamm, Jennifer; Tessanne, Kim; Murphy, Clifton N; Prather, Randall S

2014-01-01

371

Phase behavior of block copolymers in compressed carbon dioxide and as single domain-layer, nanolithographic etch resists for sub-10 nm pattern transfer  

NASA Astrophysics Data System (ADS)

Diblock copolymers have many interesting properties, which first and foremost include their ability to self-assemble into various ordered, regularly spaced domains with nanometer-scale feature sizes. The work in this dissertation can be logically divided into two parts -- the first and the majority of this work describes the phase behavior of certain block copolymer systems, and the second discusses real applications possible with block copolymer templates. Many compressible fluids have solvent-like properties dependent on fluid pressure and can be used as processing aids similar to liquid solvents. Here, compressed CO2 was shown to swell several thin homopolymer films, including polystyrene and polyisoprene, as measured by high pressure ellipsometry at elevated temperatures and pressures. The ellipsometric technique was modified to produce accurate data at these conditions through a custom pressure vessel design. The order-disorder transition (ODT) temperatures of several poly(styrene-bisoprene) diblock copolymers were also investigated by static birefringence when dilated with compressed CO2. Sorption of CO2 in each copolymer resulted in significant depressions of the ODT temperature as a function of fluid pressure, and the data above was used to estimate the quantitative amount of solvent in each of the diblock copolymers. These depressions were not shown to follow dilution approximation, and showed interesting, exaggerated scaling of the ODT at near-bulk polymer concentrations. The phase behavior of block copolymer surfactants was studied when blended with polymer or small molecule additives capable of selective hydrogen bonds. This work used small angle X-ray scattering (SAXS) to identify several low molecular weight systems with strong phase separation and ordered domains as small as 2--3 nanometers upon blending. One blend of a commercially-available surfactant with a small molecule additive was further developed and showed promise as a thin-film pattern transfer template. In this scenario, block copolymer thin films on domain thick with self-assembled feature sizes of only 6--7 nm were used as plasma etch resists. Here the block copolymer's pattern was successfully transferred into the underlying SiO2 substrate using CF4--based reactive ion etching. The result was a parallel, cylindrical nanostructure etched into SiO2.

Chandler, Curran Matthew

372

Utero-tubal embryo transfer and vasectomy in the mouse model.  

PubMed

The transfer of preimplantation embryos to a surrogate female is a required step for the production of genetically modified mice or to study the effects of epigenetic alterations originated during preimplantation development on subsequent fetal development and adult health. The use of an effective and consistent embryo transfer technique is crucial to enhance the generation of genetically modified animals and to determine the effect of different treatments on implantation rates and survival to term. Embryos at the blastocyst stage are usually transferred by uterine transfer, performing a puncture in the uterine wall to introduce the embryo manipulation pipette. The orifice performed in the uterus does not close after the pipette has been withdrawn, and the embryos can outflow to the abdominal cavity due to the positive pressure of the uterus. The puncture can also produce a hemorrhage that impairs implantation, blocks the transfer pipette and may affect embryo development, especially when embryos without zona are transferred. Consequently, this technique often results in very variable and overall low embryo survival rates. Avoiding these negative effects, utero-tubal embryo transfer take advantage of the utero-tubal junction as a natural barrier that impedes embryo outflow and avoid the puncture of the uterine wall. Vasectomized males are required for obtaining pseudopregnant recipients. A technique to perform vasectomy is described as a complement to the utero-tubal embryo transfer. PMID:24637845

Bermejo-Alvarez, Pablo; Park, Ki-Eun; Telugu, Bhanu P

2014-01-01

373

A Global View of 54,001 Single Nucleotide Polymorphisms (SNPs) on the Illumina BovineSNP50 BeadChip and Their Transferability to Water Buffalo  

E-print Network

The Illumina BovineSNP50 BeadChip features 54,001 informative single nucleotide polymorphisms (SNPs) that uniformly span the entire bovine genome. Among them, 52,255 SNPs have locations assigned in the current genome assembly (Btau_4.0), including 19,294 (37%) intragenic SNPs (i.e., located within genes) and 32,961 (63%) intergenic SNPs (i.e., located between genes). While the SNPs represented on the Illumina Bovine50K BeadChip are evenly distributed along each bovine chromosome, there are over 14,000 genes that have no SNPs placed on the current BeadChip. Kernel density estimation, a non-parametric method, was used in the present study to identify SNP-poor and SNP-rich regions on each bovine chromosome. With bandwidth = 0.05 Mb, we observed that most regions have SNP densities within 2 standard deviations of the chromosome SNP density mean. The SNP density on chromosome X was the most dynamic, with more than 30 SNP-rich regions and at least 20 regions with no SNPs. Genotyping ten water buffalo using the Illumina BovineSNP50 BeadChip revealed that 41,870 of the 54,001 SNPs are fully scored on all ten water buffalo, but 6,771 SNPs are partially scored on one to nine animals. Both fully scored and partially/no

Vanessa N. Michelizzi; Xiaolin Wu; Michael V. Dodson; Jennifer J. Michal; Jorge Zambrano-varon; Derek J. Mclean; Zhihua Jiang

374

Successful Non-Surgical Deep Uterine Transfer of Porcine Morulae after 24 Hour Culture in a Chemically Defined Medium  

PubMed Central

Excellent fertility and prolificacy have been reported after non-surgical deep uterine transfers of fresh in vivo-derived porcine embryos. Unfortunately, when this technology is used with vitrified embryos, the reproductive performance of recipients is low. For this reason and because the embryos must be stored until they are transferred to the recipient farms, we evaluated the potential application of non-surgical deep uterine transfers with in vivo-derived morulae cultured for 24 h in liquid stage. In Experiment 1, two temperatures (25°C and 37°C) and two media (one fully defined and one semi-defined) were assessed. Morulae cultured in culture medium supplemented with bovine serum albumin and fetal calf serum at 38.5°C in 5% CO2 in air were used as controls. Irrespective of medium, the embryo viability after 24 h of culture was negatively affected (P<0.05) at 25°C but not at 37°C compared with the controls. Embryo development was delayed in all experimental groups compared with the control group (P<0.001). Most of the embryos (95.7%) cultured at 37°C achieved the full or expanded blastocyst stage, and unlike the controls, none of them hatched at the end of culture. In Experiment 2, 785 morulae were cultured in the defined medium at 37°C for 24 h, and the resulting blastocysts were transferred to the recipients (n?=?24). Uncultured embryos collected at the blastocyst stage (n?=?750) were directly transferred to the recipients and used as controls (n?=?25). No differences in farrowing rates (91.7% and 92.0%) or litter sizes (9.0±0.6 and 9.4±0.8) were observed between the groups. This study demonstrated, for the first time, that high reproductive performance can be achieved after non-surgical deep uterine transfers with short-term cultured morulae in a defined medium, which opens new possibilities for the sanitary, safe national and international trade of porcine embryos and the commercial use of embryo transfer in pigs. PMID:25118944

Martinez, Emilio A.; Angel, Miguel Angel; Cuello, Cristina; Sanchez-Osorio, Jonatan; Gomis, Jesus; Parrilla, Inmaculada; Vila, Jordi; Colina, Ignaci; Diaz, Marta; Reixach, Josep; Vazquez, Jose Luis; Vazquez, Juan Maria; Roca, Jordi; Gil, Maria Antonia

2014-01-01

375

Controlling the Energy Transfer via Multi Luminescent Centers to Achieve White Light/Tunable Emissions in a Single-Phased X2-Type Y2SiO5:Eu(3+),Bi(3+) Phosphor For Ultraviolet Converted LEDs.  

PubMed

So far, more than 1000 UV converted phosphors have been reported for potential application in white light-emitting diodes (WLEDs), but most of them (e.g., Y2O2S:Eu, YAG:Ce or CaAlSiN3:Eu) suffer from intrinsic problems such as thermal instability, color aging or re-absorption by commixed phosphors in the coating of the devices. In this case, it becomes significant to search a single-phased phosphor, which can efficiently convert UV light to white lights. Herein, we report a promising candidate of a white light emitting X2-type Y2SiO5:Eu(3+),Bi(3+) phosphor, which can be excitable by UV light and address the problems mentioned above. Single Bi(3+)-doped X2-type Y2SiO5 exhibits three discernible emission peaks at ?355, ?408, and ?504 nm, respectively, upon UV excitation due to three types of bismuth emission centers, and their relative intensity depends tightly on the incident excitation wavelength. In this regard, proper selection of excitation wavelength can lead to tunable emissions of Y2SiO5:Bi(3+) between blue and green, which is partially due to the energy transfer among the Bi centers. As a red emission center Eu(3+) is codoped into Y2SiO5:Bi(3+), energy transfer has been confirmed happening from Bi(3+) to Eu(3+) via an electric dipole-dipole (d-d) interaction. Our experiments reveal that it is easily realizable to create the white or tunable emissions by adjusting the Eu(3+) content and the excitation schemes. Moreover, a single-phased white light emission phosphor, X2-type Y1.998SiO5:0.01Eu(3+),0.01 Bi(3+), has been achieved with excellent resistance against thermal quenching and a QE of 78%. At 200 °C, it preserves >90% emission intensity of that at 25 °C. Consequent three time yoyo experiments of heating-cooling prove no occurrence of thermal degradation. A WLED lamp has been successfully fabricated with a CIE chromaticity coordinate (0.3702, 0.2933), color temperature 4756 K, and color rendering index of 65 by applying the phosphor onto a UV LED chip. PMID:25607723

Kang, Fengwen; Zhang, Yi; Peng, Mingying

2015-02-16

376

Xenopus egg extract treatment reduced global DNA methylation of donor cells and enhanced somatic cell nuclear transfer embryo development in pigs.  

PubMed

The efficiency to produce offspring by somatic cell nuclear transfer (SCNT) is low. It has been showed that treatment of donor cells with Xenopus oocyte extract increased live births in ovine and handmade cloned embryo development in pigs. Scriptaid treatment after oocyte activation is another approach to improve SCNT efficiency. The present study was carried out to investigate (a) the effects of treatment of donor cells with Xenopus egg extract on donor cell DNA methylation at days 0 and 4 with two digitonin permeabilization concentrations (10 and 15??g/mL), (b) the effects of treatment of donor cells with Xenopus egg extract on early development of cloned embryos, and (c) the effects of combined treatments, treating donor cells with extract before nuclear transfer and treatment of cloned embryos with scriptaid after oocyte activation, on embryo development. Compared to the control, a decrease of DNA methylation in donor cells was observed at 2.5?h after extract treatment. However, this effect was not observed after the cells were cultured for four more days. More embryos developed into blastocysts in the Xenopus egg extract-treated group than in the control (13.4±1.9% vs. 9.1±1.9%, p=0.01). Furthermore, scriptaid treatment of cloned embryos further increased the frequency of development to blastocyst, compared to the control reconstructed with the same extract-treated cells (22.5±0.9% vs. 15.3±0.9%, p<0.01). In addition, egg extract treatments increased the cell number in the blastocysts. This study demonstrated that Xenopus egg extract treatment reduced donor cell DNA methylation and enhanced the SCNT embryo development. Moreover, the combined treatments of donor cells with egg extract before nuclear transfer and of cloned embryos with scriptaid could improve cloned embryo development additively. PMID:23515109

Yang, Xiaoyu; Mao, Jiude; Walters, Eric M; Zhao, Ming-Tao; Teson, Jennifer; Lee, Kiho; Prather, Randall S

2012-04-01

377

Supplementing culture and vitrification-warming media with l-ascorbic acid enhances survival rates and redox status of IVP porcine blastocysts via induction of GPX1 and SOD1 expression.  

PubMed

The present study sought to determine the effect of adding l-ascorbic acid (AC) to (1) in vitro culture medium and (2) vitrification and warming solutions on redox status and developmental ability and quality of IVP porcine embryos. In both experiments, embryo quality was analysed in terms of total cell number (TCN), DNA fragmentation, intracellular peroxide levels and expression of three oxidative stress-related genes: glutathione peroxidase 1 (GPX1), superoxide dismutase 1 (SOD1) and 2 (SOD2). In the first experiment, fresh blastocysts were found to upregulate SOD1 expression when cultured with medium supplemented 100 ?M AC. No differences were found between culture groups in the other analysed parameters. In the second experiment, blastocysts cultured with or without AC were divided into two groups: vitrified and warmed with solutions containing 0 or 100 ?M AC. Addition of AC during culture and vitrification-warming upregulated the expression of GPX1 and SOD1 genes, enhanced survival rates and decreased peroxide levels at 24h post-warming. In addition, peroxide levels were negatively correlated with relative GPX1- and SOD1-transcript abundances, whereas GPX1 was positively correlated with embryo survival at 24h post-warming. No effects of AC-supplementation were seen for TCN, DNA fragmentation or relative SOD2-transcript abundance in vitrified blastocysts. In conclusion, the addition of AC to culture and vitrification-warming media increases gene expression of antioxidant enzymes SOD1 and GPX1. This appears to improve redox balance and is suggested to ultimately enhance embryo cryosurvival. PMID:24657197

Castillo-Martín, Miriam; Bonet, Sergi; Morató, Roser; Yeste, Marc

2014-06-01

378

Embryo collection and transfer in the dog  

E-print Network

in TC Medium 199 containing fetal calf serum and antibiotics. Their data indicate that canine oocytes will mature in culture but, capacitated sperm are capable of penetration of the zona pellucida and vitellus and decon- densation of the sperm... Norula Early Blastocyst Late Blastocyst 18 23 Hatched 22 Empty Zona Pellucida Unfertilized 22 29 TABLE 2. Numbers of corpora lutea estimated by ovarian palpation and actual number of embryos collected. Animal No. 8139 5493 7561 88851...

Kinney, Gail Marie

2012-06-07

379

Transfer factor.  

PubMed

Transfer factor, a natural substance of the immune system, was discovered in 1949. More than 3,000 scientific articles have established it as an effective treatment for many diseases, usually those related to the immune system. In China, more than six million people have used transfer factor as a prophylaxis for hepatitis. Information on ordering articles on transfer factor, olive leaf extract, and coconut oil is included. PMID:11366549

1998-01-01

380

Heat Transfer  

NSDL National Science Digital Library

Students explore heat transfer and energy efficiency using the context of energy efficient houses. They gain a solid understanding of the three types of heat transfer: radiation, convection and conduction, which are explained in detail and related to the real world. They learn about the many ways solar energy is used as a renewable energy source to reduce the emission of greenhouse gasses and operating costs. Students also explore ways in which a device can capitalize on the methods of heat transfer to produce a beneficial result. They are given the tools to calculate the heat transferred between a system and its surroundings.

Integrated Teaching and Learning Program,

381

Interspecies somatic cell nuclear transfer and preliminary data for horse-cow/mouse iSCNT.  

PubMed

Nuclear transfer (NT) experiments in mammals have demonstrated that adult cells are genetically equivalent to early embryonic cells and the reversal of the differentiated state of a cell to another that has characteristics of the undifferentiated embryonic state can be defined as nuclear reprogramming. The feasibility of interspecies somatic cell NT (iSCNT) has been demonstrated by blastocyst formation and the production of offspring in a number of studies. Embryo and oocyte availability is a major limiting factor in conducting NT to obtain, blastocysts for both reproductive NT studies in genetically endangered animals and in embryonic stem cell derivation for species such as the horse and human. One approach to generate new embryonic stem cells in human as disease models, or in species where embryos and oocytes are not widely available, is to use oocytes from another species. Utilization of oocytes for recipient cytoplasts from other species that are accessible and abundant, such as the cow and rabbit, would greatly benefit ongoing research on reprogramming and stem cell sciences. The use of iSCNT is an exciting possibility for species with limited availability of oocytes as well as for endangered or exotic species where assisted reproduction is needed. However, the mechanisms involved in nuclear reprogramming by the oocyte are still unknown and the extent of the "universality" of ooplasmic reprogramming of development remains under investigation. PMID:17848714

Tecirlioglu, R Tayfur; Guo, Jitong; Trounson, Alan O

2006-01-01

382

Development and calcium level changes in pre-implantation porcine nuclear transfer embryos activated with 6-DMAP after fusion.  

PubMed

This study investigated the effect of treatment with 6-dimethylaminopurine (6-DMAP) following fusion on in vitro development of porcine nuclear transfer (NT) embryos. Frozen thawed ear skin cells were transferred into the perivitelline space of enucleated oocytes. Reconstructed oocytes were fused and activated with electric pulse in 0.3 M mannitol supplemented with either 0.1 or 1.0 mM CaCl(2). In each calcium concentration, activated oocytes were divided into three groups. Two groups of them were exposed to either ionomycin (I + 6-DMAP or 6-DMAP alone. In experiment 2, fused NT embryos in 0.3 M mannitol containing 1.0 mM CaCl(2) were exposed to 6-DMAP either immediately or 20 min after fusion/activation. For 0.1 mM CaCl(2), oocytes activated with either I + 6-DMAP or 6-DMAP alone showed a higher (P < 0.05) developmental rate to the blastocyst stage than those activated with an electric pulse alone (26.7 and 22.5 vs. 12.5%). For 1.0 mM CaCl(2), oocytes activated with either I + 6-DMAP or 6-DMAP alone showed significantly higher (P < 0.05) developmental rate to the blastocyst stage (35.6 and 28.3 vs. 19.8%). Developmental rate to the blastocyst stage was (P < 0.05) increased in NT embryos activated with 6-DMAP 20 min after fusion. 6-DMAP made a higher and wider Ca(2+) transient compared to that induced by electric pulses (Fig. 3). The fluctuation lasted during the time that oocytes were cultured in 6-DMAP. Regardless of Ca(2+) concentration in fusion medium, activation with 6-DMAP following electric pulses supported more development of porcine NT embryos. Activation of NT embryos with 6-DMAP after fusion in the presence of 1.0 mM CaCl(2) could support better developmental rate to the blastocyst stage. PMID:17366547

Im, Gi-Sun; Samuel, Melissa; Lai, Liangxue; Hao, Yanhong; Prather, Randall S

2007-09-01

383

Hollow fiber vitrification: a novel method for vitrifying multiple embryos in a single device.  

PubMed

Current embryo vitrification methods with proven efficacy are based on the minimum volume cooling (MVC) concept by which embryos are vitrified and rewarmed ultrarapidly in a very small amount of cryopreserving solution to ensure the high viability of the embryos. However, these methods are not suitable for simultaneously vitrifying a large number of embryos. Here, we describe a novel vitrification method based on use of a hollow fiber device, which can easily hold as many as 40 mouse or 20 porcine embryos in less than 0.1 ?l of solution. Survival rates of up to 100% were obtained for mouse embryos vitrified in the presence of 15% DMSO, 15% ethylene glycol and 0.5 M sucrose using the hollow fiber vitrification (HFV) method, regardless of the developmental stage of the embryos (1-cell, 2-cell, morula or blastocyst; n = 50/group). The HFV method was also proven to be effective for vitrifying porcine in vitro- and in vivo-derived embryos that are known to be highly cryosensitive. For porcine embryos, the blastocyst formation rate of in vitro maturation (IVM)-derived parthenogenetic morulae after vitrification (48/65, 73.8%) did not decrease significantly compared with non-vitrified embryos (59/65, 90.8%). Transfer of 72 in vivo-derived embryos vitrified at the morula/early blastocyst stages to 3 recipients gave rise to 29 (40.3%) piglets. These data demonstrate that the HFV method enables simultaneous vitrification of multiple embryos while still adhering to the MVC concept, and this new method is very effective for cryopreserving embryos of mice and pigs. PMID:22785381

Matsunari, Hitomi; Maehara, Miki; Nakano, Kazuaki; Ikezawa, Yuka; Hagiwara, Yui; Sasayama, Norihisa; Shirasu, Akio; Ohta, Hisayoshi; Takahashi, Masashi; Nagashima, Hiroshi

2012-01-01

384

Characterization of the Altered Gene Expression Profile in Early Porcine Embryos Generated from Parthenogenesis and Somatic Cell Chromatin Transfer  

PubMed Central

The in vitro production of early porcine embryos is of particular scientific and economic interest. In general, embryos produced from in vitro Assisted Reproductive Technologies (ART) manipulations, such as somatic cell chromatin transfer (CT) and parthenogenetic activation (PA), are less developmentally competent than in vivo–derived embryos. The mechanisms underlying the deficiencies of embryos generated from PA and CT have not been completely understood. To characterize the altered genes and gene networks in embryos generated from CT and PA, comparative transcriptomic analyses of in vivo (IVV) expanded blastocysts (XB), IVV hatched blastocyst (HB), PA XB, PA HB, and CT HB were performed using a custom microarray platform enriched for genes expressed during early embryonic development. Differential expressions of 1492 and 103 genes were identified in PA and CT HB, respectively, in comparison with IVV HB. The “eIF2 signalling”, “mitochondrial dysfunction”, “regulation of eIF4 and p70S6K signalling”, “protein ubiquitination”, and “mTOR signalling” pathways were down-regulated in PA HB. Dysregulation of notch signalling–associated genes were observed in both PA and CT HB. TP53 was predicted to be activated in both PA and CT HB, as 136 and 23 regulation targets of TP53 showed significant differential expression in PA and CT HB, respectively, in comparison with IVV HB. In addition, dysregulations of several critical pluripotency, trophoblast development, and implantation-associated genes (NANOG, GATA2, KRT8, LGMN, and DPP4) were observed in PA HB during the blastocyst hatching process. The critical genes that were observed to be dysregulated in CT and PA embryos could be indicative of underlying developmental deficiencies of embryos produced from these technologies. PMID:24633136

Zhou, Chi; Dobrinsky, John; Tsoi, Stephen; Foxcroft, George R.; Dixon, Walter T.; Stothard, Paul; Verstegen, John; Dyck, Michael K.

2014-01-01

385

Telomere length in human blastocysts.  

PubMed

This is a retrospective study aiming to assess telomere length in human embryos 4 days post fertilization and to determine whether it is correlated to chromosomal ploidy, embryo developmental rate and patient age. Embryos were donated from patients undergoing treatment in the assisted conception unit. Seven couples took part, generating 35 embryos consisting of 1130 cells. Quantitative fluorescent in-situ hybridization (FISH) measured the telomere length of every cell using a pan-telomeric probe. Conventional FISH on six chromosomes was used to assess aneuploidy in the same cells. Maternal and paternal age, referral reason, embryo developmental rate and type of chromosomal error were taken into account. Chromosomally abnormal cells were associated with shorter telomeres than normal cells for embryos that were developmentally slow. Cells produced by women of advanced maternal age and those with a history of repeated miscarriage tended to have substantially shorter telomeres. There was no significant difference in telomere length with respect to the rate of embryo development 5 days post fertilization. Telomeres play an important role in cell division and shorter telomeres may affect embryonic ploidy. Reduced telomere length was associated with aneuploid cells and embryos from women of advanced maternal age. PMID:24581987

Mania, Anastasia; Mantzouratou, Anna; Delhanty, Joy D A; Baio, Gianluca; Serhal, Paul; Sengupta, Sioban B

2014-05-01

386

"Transfer Shock" or "Transfer Ecstasy?"  

ERIC Educational Resources Information Center

The alleged characteristic drop in grade point average (GPA) of transfer students and the subsequent rise in GPA was investigated in this study. No statistically significant difference was found in first term junior year GPA between junior college transfers and native Florida State University students after the variance accounted for by the…

Nickens, John M.

387

Heat-transfer augmentation in rod bundles near grid spacers  

Microsoft Academic Search

Heat-transfer augmentation by straight grid spacers in rod bundles is studied for single-phase flow and for post-critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single-phase flow is also examined. Governing heat-transfer mechanisms are analyzed, and predictive formulations are established. For single-phase flow, the local heat transfer at a straight spacer and at its upstream

S. C. Yao; L. E. Hochreiter; W. J. Leech

1982-01-01

388

Development of in vitro matured, in vitro fertilized domestic cat embryos following cryopreservation, culture and transfer.  

PubMed

The ability of embryos to successfully survive cryopreservation is dependent on both morphological and developmental characteristics. Domestic cat oocytes matured in vitro exhibit alterations in nuclear and cytoplasmic maturation that may affect developmental competence, particularly after cryopreservation. In Experiment 1, we evaluated the developmental competence of in vitro produced (IVM/IVF) cat embryos after cryopreservation on Days 2, 4 or 5 of IVC. In Experiment 2, in vivo viability was examined by transfer of cryopreserved embryos into recipient queens. Oocytes recovered from minced ovaries were cultured in TCM-199 with hCG/eCG and EGF at 38 degrees C in 5% O(2), 5% CO(2), 90% N(2) for 24h. In Experiment 1, after IVM/IVF, on Day 2 (n=56), Day 4 (n=48) and Day 5 (n=42) of IVC, embryos were equilibrated for 10 min at 22 degrees C in HEPES (15m M) Tyrode's (HeTy) with 1.4M propylene glycol (PG), 0.125 M sucrose (S), 10% dextran and 10% FBS, loaded into 0.25 ml straws, cooled at 2.0 degrees C/min to -6.0 degrees C and held for 10 min. After seeding, cooling resumed at 0.3 degrees C/min to -30 degrees C and after a 10 min hold, straws were plunged into liquid nitrogen (LN(2)). Straws were thawed in air for 2 min and cryoprotectant was removed by a five-step rinse consisting of 3 min each in HeTY with 0.95 M PG/0.25 M S; 0.95 M PG/0.125 M S; 0.45 M PG/0.125 M S; 0 PG/0.125 M S; 0 PG/0.0625 M S. Contemporary IVM/IVF embryos were used as nonfrozen controls (Day 2, n=14; Day 4, n=26; Day 5, n=35). After 8 days of IVC, the number of embryos developing to blastocysts was recorded and blastocyst cell numbers were counted after staining with Hoechst 33342. In Experiment 1, developmental stage did not affect the survival rate after thawing (Day 2=79%, Day 4=90%, Day 5=98%) and was not different from that of controls (Day 2=89%, Day 4=88%, Day 5=96%). Blastocyst development was similar among days both after cryopreservation (Day 2=59%, Day 4=54%, Day 5=63%) and in controls (Day 2=55%, Day 4=54%, Day 5=58%). Mean (+/-S.D.) cell number of blastocysts was slightly lower (NS) in cryopreserved embryos (Day 2=152+/-19, Day 4=124+/-20, Day 5=121+/-24) than in controls (Day 2=141+/-25, Day 4=169+/-21, Day 5=172+/-19). In Experiment 2, embryos frozen on Day 2 (n=68), Day 4 (n=49) or Day 5 (n=73) were thawed and cultured for 3, 1, or 0 days before transfer by laparotomy to 5 (mean=12.6+/-2.4), 4 (mean=12.2+/-3.7) and 6 (mean=12.0+/-1.6) recipients, respectively. Four recipients were pregnant on Day 21; two from embryos frozen on Day 4 and two from Day 5. Two live kittens were born at 66 days, a third kitten died during parturition at 64 days and a fourth pregnancy aborted by Day 45. In summary, we have shown that a controlled rate cryopreservation technique can be successfully applied to cat embryos produced by IVM/IVF. In vitro development to the blastocyst stage was not affected by the age of embryos at cryopreservation. The births of live kittens after ET of cryopreserved embryos is additional validation of progress toward applying assisted reproductive technology to preservation of endangered felids. PMID:12749937

Gómez, Martha C; Pope, Earle; Harris, Rebecca; Mikota, Susan; Dresser, Betsy L

2003-07-01