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1

Association between blastocyst morphology and outcome of single-blastocyst transfer.  

PubMed

The aim of this study was to assess the ability of three individual blastocyst morphology parameters - expansion and hatching (EH) stage, inner cell mass (ICM) grade and trophectoderm grade - to predict outcome of a cycle with single-blastocyst transfer. The study was a secondary analysis of data prospectively collected in a large multicentre trial. A total of 618 intracytoplasmic sperm injection patients undergoing ovarian stimulation in a gonadotrophin-releasing hormone antagonist cycle with compulsory single-blastocyst transfer on day 5 were included. In the simple logistic regression analysis, all three blastocyst morphology parameters were statistically significantly (P<0.005 for each) associated with positive human chorionic gonadotrophin, clinical and ongoing pregnancy rates and live birth rates, while only the ICM grade was significantly (P=0.033) associated with early pregnancy loss rate. Blastocyst EH stage was the only significant predictor of live birth (P=0.002) in the multiple logistic regression. In conclusion, although all three blastocyst morphology parameters were related to treatment outcome of fresh single-blastocyst cycles, selection of high-quality blastocysts for transfer should consider first the EH stage. Transfer of a blastocyst with ICM grade A may reduce the risk of early pregnancy loss. Choosing the embryo(s) with the best implantation potential is essential for securing each couple the highest chance of achieving pregnancy after assisted reproduction. The selection of embryo(s) for transfer at the blastocyst stage is based on morphology parameters of expansion and hatching stage, inner cell mass grade and trophectoderm grade. The aim of this study was to assess the relative impact of each parameter in predicting the probability of a successful outcome. The study was a secondary analysis of data prospectively collected in a large multicentre trial. A total of 618 patients who underwent single-blastocyst transfer on day 5 were included. Statistical analysis showed that all three blastocyst morphology parameters were significantly associated with positive human chorionic gonadotrophin (?HCG), clinical and ongoing pregnancy rates and live birth rates. Only the inner cell mass grade was significantly associated with early pregnancy loss between the positive ?HCG test and confirmation of ongoing pregnancy 10-11weeks after transfer. The expansion and hatching stage was the only significant predictor of live birth in the multiple logistic regression analysis. In conclusion, although all three blastocyst morphology parameters were related to treatment outcome of fresh single-blastocyst cycles, selection of high-quality blastocysts for transfer should consider first the expansion and hatching stage. Transfer of a blastocyst with inner cell mass grade A may reduce the risk of early pregnancy loss. PMID:23953585

Van den Abbeel, Etienne; Balaban, Basak; Ziebe, Søren; Lundin, Kersti; Cuesta, Maria José Gómez; Klein, Bjarke Mirner; Helmgaard, Lisbeth; Arce, Joan-Carles

2013-07-18

2

Clinical outcome of frozen blastocyst transfer; single vs. double transfer  

Microsoft Academic Search

Purpose  Frozen embryo transfer has been established as an indispensable ART procedure for both the effective use of surplus embryos\\u000a and the prevention of ovarian hyperstimulation syndrome. The frequency of frozen embryo transfer is increasing in our clinic,\\u000a and we report that frozen embryo transfer is effective for patients with repeat failures. We present our clinical outcome\\u000a of frozen blastocyst transfer

Atsushi Yanaihara; Takeshi Yorimitsu; Hiroshi Motoyama; Motohiro Ohara; Toshihiro Kawamura

2008-01-01

3

Blastocyst transfer and monozygotic twinning  

Microsoft Academic Search

Objective: To report two cases of monozygotic twinning after IVF-blastocyst transfer.Design: Case report.Setting: Private practice in an assisted reproductive technology clinic.Patient(s): Two women treated with IVF-ET at the blastocyst stage.Intervention(s): Pituitary down-regulation with luteal leuprolide acetate, ovulation induction with gonadotropins, IVF, sequential culture, blastocyst transfer, and P for luteal support.Main Outcome Measure(s): Levels of hCG, pelvic ultrasound examination, amniocentesis, obstetric

Braulio Peramo; Elisabetta Ricciarelli; Jorge M. Cuadros-Fernández; Eva Huguet; Eleuterio Rodrigo Hernández

1999-01-01

4

Developmental stage on day-5 and fragmentation rate on day-3 can influence the implantation potential of top-quality blastocysts in IVF cycles with single embryo transfer  

Microsoft Academic Search

BACKGROUND: In IVF-ICSI cycles with single embryo transfer (SET), embryo selection for transfer is of crucial importance. The present study aimed to define which embryo parameters might be related to the implantation potential of advanced blastocysts. METHODS: Overall, in 203 cycles with SET, developmental characteristics of 93 implanted (group A) and 110 non-implanted (group B) advanced blastocysts of good quality

Tiziana della Ragione; Greta Verheyen; Evangelos G Papanikolaou; Lisbet Van Landuyt; Paul Devroey; Andre Van Steirteghem

2007-01-01

5

Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study  

PubMed Central

Background Single embryo transfer (SET) remains underutilized as a strategy to reduce multiple gestation risk in IVF, and its overall lower pregnancy rate underscores the need for improved techniques to select one embryo for fresh transfer. This study explored use of comprehensive chromosomal screening by array CGH (aCGH) to provide this advantage and improve pregnancy rate from SET. Methods First-time IVF patients with a good prognosis (age <35, no prior miscarriage) and normal karyotype seeking elective SET were prospectively randomized into two groups: In Group A, embryos were selected on the basis of morphology and comprehensive chromosomal screening via aCGH (from d5 trophectoderm biopsy) while Group B embryos were assessed by morphology only. All patients had a single fresh blastocyst transferred on d6. Laboratory parameters and clinical pregnancy rates were compared between the two groups. Results For patients in Group A (n?=?55), 425 blastocysts were biopsied and analyzed via aCGH (7.7 blastocysts/patient). Aneuploidy was detected in 191/425 (44.9%) of blastocysts in this group. For patients in Group B (n?=?48), 389 blastocysts were microscopically examined (8.1 blastocysts/patient). Clinical pregnancy rate was significantly higher in the morphology?+?aCGH group compared to the morphology-only group (70.9 and 45.8%, respectively; p?=?0.017); ongoing pregnancy rate for Groups A and B were 69.1 vs. 41.7%, respectively (p?=?0.009). There were no twin pregnancies. Conclusion Although aCGH followed by frozen embryo transfer has been used to screen at risk embryos (e.g., known parental chromosomal translocation or history of recurrent pregnancy loss), this is the first description of aCGH fully integrated with a clinical IVF program to select single blastocysts for fresh SET in good prognosis patients. The observed aneuploidy rate (44.9%) among biopsied blastocysts highlights the inherent imprecision of SET when conventional morphology is used alone. Embryos randomized to the aCGH group implanted with greater efficiency, resulted in clinical pregnancy more often, and yielded a lower miscarriage rate than those selected without aCGH. Additional studies are needed to verify our pilot data and confirm a role for on-site, rapid aCGH for IVF patients contemplating fresh SET.

2012-01-01

6

Blastocyst transfer in frozen-thawed cycles  

PubMed Central

Objective It is well known that fresh blastocyst transfer results in better pregnancy outcomes with a smaller number of transferred embryos compared with cleavage stage embryo transfer. However, in terms of frozen-thawed blastocyst transfer, only a few studies are available. We aimed to evaluate clinical outcomes of frozen-thawed embryo transfer (FET) with blastocysts. Methods Retrospective analysis of FET cycles with blastocysts (B-FET) between Jan 2007 and June 2009 was performed. Age-matched FET cycles with cleavage stage embryos (C-FET) during the same period were collected as controls. A total of 58 B-FET cycles were compared with 172 C-FET cycles and also compared with those of post-thaw extended culture blastocysts from frozen pronuclear stage embryos (22 cycles). Results There was no difference in the patient characteristics of each group. The embryos' survival rates after thawing were comparable (>90%) and there was no difference in the implantation rate or clinical and ongoing pregnancy rate among the three groups. Conclusion In FET, blastocyst transfers may not present better pregnancy outcomes than cleavage stage embryo transfers. A further large-scale prospective study is needed.

Han, Ae Ra; Lee, Hyoung-Song; Yang, Kwang Moon; Song, In Ok; Koong, Mi Kyoung

2012-01-01

7

Blastocyst quality affects the success of blastocyst-stage embryo transfer  

Microsoft Academic Search

Objective:To determine the relationship between blastocyst quality and the results of embryo transfer at the blastocyst stage.Design:Retrospective case analysis.Setting:Tertiary care private hospital IVF center.Patient(s):A total of 350 blastocyst-stage embryo transfer cycles.Intervention(s):In vitro culture to the blastocyst stage was undertaken in 350 ICSI cycles where four or more cleavage-stage embryos were available on day 3.Main Outcome Measure(s):Relationship between blastocyst quality and

Basak Balaban; Bulent Urman; Aycan Sertac; Cengiz Alatas; Senai Aksoy; Ramazan Mercan

2000-01-01

8

Gene expression profiling of individual bovine nuclear transfer blastocysts  

Microsoft Academic Search

During somatic cell nuclear transfer the gene expression profile of the donor cell has to be changed or reprogrammed extensively to reflect that of a normal embryo. In this study we focused on the switching on of embryonic genes by screening with a microarray consisting of 5000 independent cDNA isolates derived from a bovine blastocyst library which we constructed for

Joanna Somers; Craig Smith; Martyn Donnison; David N Wells; Harold Henderson; Lance McLeay; P L Pfeffer

2006-01-01

9

In vitro fertilization and blastocyst transfer for carriers of chromosomal translocation  

Microsoft Academic Search

Blastocyst transfers (BT), may benefit chromosomal translocation-carrier couples who suffer multiple miscarriages or are unable to achieve pregnancy following classical ART techniques. In vitro culture applies an additional selection pressure, so that those embryos which achieve blastocyst formation have higher survival probability as healthy balanced translocation carriers or unaffected embryos.Sixteen IVF cycles were performed in 11 patients. When blastocyst are

Yves Ménézo; Jacques Chouteau; Anna Veiga

2001-01-01

10

Dichorionic twins and monochorionic triplets after the transfer of two blastocysts  

PubMed Central

Purpose To describe a unique case of MZ dichorionic twins and MZ monochorionic triplets in a quintuplet gestation after intracytoplasmatic sperm injection (ICSI) and blastocyst transfer. Methods Case report. A 24-year-old woman underwent ICSI and received two blastocysts transferred. A quintuplet gestation was established .Transvaginal ultrasonography was performed sequentially during early pregnancy. Results Three intrauterine gestational sacs were revealed at about 5th week. At the 7th week, five gestational sacs presenting heart beats were detected and a quintuplet pregnancy consisting of two monozygotic (MZ) dichorionic twins and three MZ monochorionic triplets was determined. At the 10th week, a single gestational sac with heart beats was detected. The prenatal course was uneventful. A healthy baby was born at 36th week. Conclusion Few other reports have described the occurrence of a quintuplet gestation after the transfer of two blastocysts generated by ICSI. Our case is unique in that the two blastocysts underwent two different splitting processes, which occurred possibly at a similar time giving rise to MZ dichorionic twins and MZ monochorionic triplets.

Ferreira, Marcelo; Hoher, Marcos; Frantz, Nilo

2010-01-01

11

RNA-seq analysis of single bovine blastocysts  

PubMed Central

Background Use of RNA-Seq presents unique benefits in terms of gene expression analysis because of its wide dynamic range and ability to identify functional sequence variants. This technology provides the opportunity to assay the developing embryo, but the paucity of biological material available from individual embryos has made this a challenging prospect. Results We report here the first application of RNA-Seq for the analysis of individual blastocyst gene expression, SNP detection, and characterization of allele specific expression (ASE). RNA was extracted from single bovine blastocysts (n = 5), amplified, and analyzed using high-throughput sequencing. Approximately 38 million sequencing reads were generated per embryo and 9,489 known bovine genes were found to be expressed, with a high correlation of expression levels between samples (r > 0.97). Transcriptomic data was analyzed to identify SNP in expressed genes, and individual SNP were examined to characterize allele specific expression. Expressed biallelic SNP variants with allelic imbalances were observed in 473 SNP, where one allele represented between 65-95% of a variant’s transcripts. Conclusions This study represents the first application of RNA-seq technology in single bovine embryos allowing a representation of the embryonic transcriptome and the analysis of transcript sequence variation to describe specific allele expression.

2013-01-01

12

[Heterotopic pregnancy with intrauterine dizygotic twins following embryo transfer in the blastocyst phase].  

PubMed

Ectopic pregnancy is a common complication of in vitro fertilization and embryo transfer (IVF-ET). On other hand, heterotopic pregnancy complicates 1-2% of all IVF-ET pregnancies. Tubal damage as reason for treatment and multiple embryo transfer might predispose patients to this complication. We present a successful treated case of an infertile patient that developed simultaneous twin intra- and single extra- uterine pregnancy after blastocyst-stage embryo transfer. In IVF-ET patients presence of an intrauterine gestation not exclude the possibility of a concomitant extrauterine pregnancy. Awareness of the possibility of heterotopic pregnancy after IVF-ET plays an important role in the successful treatment of this reproductive complication. Transfer of good quality embryos can be a risk factor to develop heterotopic pregnancy. PMID:10363416

Barrón Vallejo, J; Ortega Díaz, R; Kably Ambe, A

1999-04-01

13

Aberrant DNA Methylation in Porcine in vitro-, Parthenogenetic-, and Somatic Cell Nuclear Transfer-Produced Blastocysts  

PubMed Central

Early embryonic development in the pig requires DNA methylation remodeling of the maternal and paternal genomes. Aberrant remodeling, which can be exasperated by in vitro technologies, is detrimental to development and can result in physiological and anatomic abnormalities in the developing fetus and offspring. Here, we developed and validated a microarray based approach to characterize on a global scale the CpG methylation profiles of porcine gametes and blastocyst stage embryos. The relative methylation in the gamete and blastocyst samples showed that 18.5% (921/4992) of the DNA clones were found to be significantly different (P<0.01) in at least one of the samples. Furthermore, for the different blastocyst groups, the methylation profile of the in vitro-produced blastocysts was less similar to the in vivo-produced blastocysts as compared to the parthenogenetic- and somatic cell nuclear transfer (SCNT)-produced blastocysts. The microarray results were validated by using bisulfite sequencing for 12 of the genomic regions in liver, sperm, and in vivo-produced blastocysts. These results suggest that a generalized change in global methylation is not responsible for the low developmental potential of blastocysts produced by using in vitro techniques. Instead, the appropriate methylation of a relatively small number of genomic regions in the early embryo may enable early development to occur.

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

2008-01-01

14

Optimization of cryopreservation of buffalo (Bubalus bubalis) blastocysts produced by in vitro fertilization and somatic cell nuclear transfer.  

PubMed

The objective of this study was to optimize cryopreservation conditions for buffalo in vitro produced (IVP) embryos. The in vitro fertilized (IVF) and somatic cell nuclear transferred (SCNT) blastocysts were vitrified with either 40% ethylene glycol (EG), 25% EG + 25% dimethylsulfoxide (DMSO), or 20% EG + 20% DMSO + 0.5 m sucrose, and the IVF blastocysts produced from abattoir-derived ovaries were also slow-frozen with either 10% EG or 0.05 m trehalose dehydrate + 1.8% EG + 0.4% BSA. Cryosurvival rates of blastocysts harvested on various days or at various developmental stages were also examined. In this study: (1) vitrification with 20% EG + 20% DMSO + 0.5 m sucrose had the best cryopreservation efficiency; (2) IVF and SCNT blastocysts had similar cryotolerance (P > 0.05); (3) after thawing, slow-frozen blastocysts reexpanded earlier than the vitrified blastocysts (P < 0.01); (4) cryosurvival rate of expanded blastocysts was higher than that of early blastocysts (P < 0.05); (5) cryosurvival rates of Days 5 to 7 blastocysts (Day 0 = day of IVF or SCNT) were higher than those of Days 8 to 9 blastocysts (P < 0.01); and (6) after embryo transfer, pregnancy rates for fresh and cryopreserved blastocysts were not different (P > 0.05). In conclusion, vitrification of Days 6 to 7 expanded blastocysts with 20% EG + 20% DMSO + 0.5 m sucrose was optimal for cryopreservation of buffalo IVP embryos. PMID:22925650

Yang, C Y; Pang, C Y; Yang, B Z; Li, R C; Lu, Y Q; Liang, X W

2012-08-24

15

Retrospective analysis of outcomes following transfer of previously cryopreserved oocytes, pronuclear zygotes and supernumerary blastocysts  

Microsoft Academic Search

Oocyte cryopreservation still bears the experimental label. Remarkable innovation in this field has led to immense improvement in clinical outcomes and has even resulted in outcomes comparable to those achieved following fresh embryo transfers. Such success has prompted this centre to investigate outcomes of cryopreservation options (oocyte versus pronuclear zygote versus supernumerary day-5 blastocyst after fresh embryo transfer). This study

Brooke Hodes-Wertz; Nicole Noyes; Christine Mullin; Caroline McCaffrey; Jamie A. Grifo

2011-01-01

16

Developmentally retarded frozen blastocysts can be rescued by synchronizing culture prior to transfer  

Microsoft Academic Search

Asynchrony between embryo development and endometrial differentiation is the limiting step of successful pregnancy in assisted reproduction. The aim of this study was to investigate whether or not post-thaw synchronization culture of day 5–6 frozen embryos, prior to transfer, with endometrial differentiation resulted in pregnancy. A total of 142 cycles of 134 patients were transferred in three protocols. Blastocysts with

Takafumi Utsunomiya; Hiroko Ito; Kaori Hirai; Eiko Otsu; Hirohiko Watanabe; Takahide Mori

2006-01-01

17

CLINICAL ASSISTED REPRODUCTION: Births After Transfer of Zona-Free Blastocysts in Oocyte Donation Cycles  

Microsoft Academic Search

Purpose: Oocyte donation is a well-established method of assisted reproduction for women with irreversible infertility and with previous implantation failures after in vitro fertilization. Although the pregnancy rates are very high, sometimes implantation does not occur even after various attempts. We report the first two cases of transfer of zona-free blastocysts in oocyte donation cycles that developed to normal pregnancies

Marcos A. C. Sampaío; Selmo Geberw

2001-01-01

18

Derivation of a human blastocyst after heterologous nuclear transfer to donated oocytes  

Microsoft Academic Search

This paper describes the derivation of a blastocyst following heterologous nuclear transfer (NT) into a human oocyte. It also demonstrates that a major obstacle to continuing research in human NT is the availability of suitable human oocytes. In this study, 36 oocytes were donated by 11 women undergoing four different treatments and their developmental potential was evaluated after NT. The

Stojkovic Miodrag; Stojkovic Petra; Leary Christine; Jane Hall Vanessa; Armstrong Lyle; Herbert Mary; Nesbitt Maria; Lako Majlinda; Murdoch Alison

2005-01-01

19

The effect of pronuclear morphology on embryo quality parameters and blastocyst transfer outcome  

Microsoft Academic Search

BACKGROUND: Embryo quality may be accurately assessed as early as the pronuclear zygote phase, as shown in recent studies. However, it is not known whether good quality zygotes are destined to become good quality cleavage stage embryos and blastocysts. METHODS: In this retrospective study, 86 intracytoplasmic sperm injection-embryo transfer cycles were studied where each available embryo was scored from the

Basak Balaban; Bulent Urman; Aycan Isiklar; Cengiz Alatas; Senai Aksoy; Ramazan Mercan; Alper Mumcu; Alp Nuhoglu

2001-01-01

20

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

2012-09-16

21

Totipotency and Normal Differentiation of Single Teratocarcinoma Cells Cloned by Injection into Blastocysts  

Microsoft Academic Search

A definitive test for developmental totipotency of mouse malignant teratocarcinoma cells was conducted by cloning singly injected cells in genetically marked blastocysts. Totipotency was conclusively shown in an adult mosaic female whose tumor-strain cells had made substantial contributions to all of the wide range of its somatic tissues analyzed; the clonally propagated cell lineage had therefore differentiated in numerous normal

Karl Illmensee; Beatrice Mintz

1976-01-01

22

Selection of euploid blastocysts for cryopreservation with array comparative genomic hybridization (aCGH) results in increased implantation rates in subsequent frozen and thawed embryo transfer cycles  

PubMed Central

Background In assisted reproductive treatments, embryos remaining after fresh embryo transfer are usually selected for cryopreservation based on traditional morphology assessment. Our previous report has demonstrated that array comparative genomic hybridization (aCGH) screening for IVF patients with good prognosis significantly improves clinical and ongoing pregnancy rates in fresh embryo transfer cycles. The current study further investigates the efficiency of applying aCGH in the selection of euploid embryos for cryopreservation as related to pregnancy and implantation outcomes in subsequent frozen embryo transfer (FET) cycles. Methods First-time IVF patients with good prognosis undergoing fresh single embryo transfer and having at least one remaining blastocyst for cryopreservation were prospectively randomized into two groups: 1) Group A patients had embryos assessed by morphology first and then by aCGH screening of trophectoderm cells and 2) Group B patients had embryos evaluated by morphology alone. All patients had at least one blastocyst available for cryopreservation after fresh embryo transfer. There were 15 patients in Group A and 23 patients in Group B who failed to conceive after fresh embryo transfer and completed the FET cycles. Blastocyst survival and implantation rates were compared between the two groups. Results There were no significant differences in blastocyst survival rates between Group A and Group B (90.9% vs. 91.3%, respectively; p >0.05). However, a significantly higher implantation rate was observed in the morphology assessment plus aCGH screening group compared to the morphology assessment alone group (65.0% vs. 33.3%, respectively; p?=?0.038). There was no miscarriage observed in Group A while a 16.7% miscarriage rate was recorded in Group B (0% vs. 16.7%, respectively; p >0.05). Conclusions While aCGH screening has been recently applied to select euploid blastocysts for fresh transfer in young, low-risk IVF patients, this is the first prospective study on the impact of aCGH specifically on blastocyst survival and implantation outcomes in the subsequent FET cycles of IVF patients with good prognosis. The present study demonstrates that aCGH screening of blastocysts prior to cryopreservation significantly improves implantation rates and may reduce the risk of miscarriage in subsequent FET cycles. Further randomized clinical studies with a larger sample size are needed to validate these preliminary findings.

2013-01-01

23

Selection of developmentally competent oocytes through brilliant cresyl blue stain enhances blastocyst development rate after bovine nuclear transfer  

Microsoft Academic Search

The aim of the present investigation was to study the effect of oocyte selection on the efficiency of bovine nuclear transfer in terms of increased blastocyst production. For this purpose, prior to in vitro maturation (IVM), oocytes were selected for their developmental competence on the basis of glucose-6-phosphate dehydrogenase (G6PDH) activity indicated by brilliant cresyl blue (BCB) staining. It has

S. Bhojwani; H. Alm; H. Torner; W. Kanitz; R. Poehland

2007-01-01

24

Gene expression regulating blastocyst formation  

Microsoft Academic Search

Development of embryos to the blastocyst stage is a critical event in the early lives of all eutherian mammalian species. Blastocyst formation is essential for implantation and is the principal morphological determinant of embryo quality prior to embryo transfer. The physiological events and roles of specific gene families that regulate blastocyst formation are subjects of intense research. Recent findings have

A. J Watson; M. E Westhusin; P. A De Sousa; D. H Betts; L. C Barcroft

1999-01-01

25

Selection of developmentally competent oocytes through brilliant cresyl blue stain enhances blastocyst development rate after bovine nuclear transfer.  

PubMed

The aim of the present investigation was to study the effect of oocyte selection on the efficiency of bovine nuclear transfer in terms of increased blastocyst production. For this purpose, prior to in vitro maturation (IVM), oocytes were selected for their developmental competence on the basis of glucose-6-phosphate dehydrogenase (G6PDH) activity indicated by brilliant cresyl blue (BCB) staining. It has been hypothesized that growing oocytes have a higher level of active G6PDH in comparison to the mature oocytes. Compact cumulus oocyte complexes (COCs) were recovered from slaughterhouse-collected bovine ovaries and classified either as control group, which were placed immediately into culture without exposure to BCB stain, or treatment group, which were stained with BCB for 90min before culture. Treated oocytes were then divided into BCB- (colourless cytoplasm, increased G6PDH) and BCB+ (coloured cytoplasm, low G6PDH) based on their ability to metabolize the stain. After IVM, oocytes were subjected to nuclear transfer procedure for the production of cloned embryos which were then cultured for a period of 8 days to determine the blastocyst rate. The BCB+ oocytes yielded a significantly higher blastocyst rate (39%) than the control (21%) or BCB- oocytes (4%). These results show that the staining of bovine cumulus-oocyte complexes with BCB before in vitro maturation could be used to select developmentally competent oocytes for nuclear transfer. In addition, G6PDH activity could prove to be a useful marker for determining the oocyte quality in future. PMID:16999988

Bhojwani, S; Alm, H; Torner, H; Kanitz, W; Poehland, R

2006-09-26

26

Development of single mouse blastomeres into blastocysts, outgrowths and the establishment of embryonic stem cells.  

PubMed

The recently developed technique of establishing embryonic stem (ES) cell lines from single blastomeres (BTMs) of early mouse and human embryos has created significant interest in this source of ES cells. However, sister BTMs of an early embryo might not have equal competence for the development of different lineages or the derivation of ES cells. Therefore, single BTMs from two- and four-cell embryos of outbred mice were individually placed in sequential cultures to enhance the formation of the inner cell mass (ICM) and the establishment of embryonic outgrowth. The outgrowths were then used for the derivation of ES cell lines. Based on the expression of ICM (Sox2) and trophectoderm (Cdx2) markers, it was determined that ICM marker was lacking in blastocysts derived from 12% of BTMs from two-cell stage and 20% from four-cell stage. Four ES cell lines (5.6%; 4/72) were established ater culture of single BTMs from two-cell embryos, and their pluripotency was demonstrated by their differentiation into neuronal cell types. Our results demonstrate that sister BTMs of an early embryo are not equally competent for ICM marker expression. However, we demonstrated the feasibility of establishing ES cells from a single BTM of outbred mice. PMID:18502895

Lorthongpanich, Chanchao; Yang, Shang-Hsun; Piotrowska-Nitsche, Karolina; Parnpai, Rangsun; Chan, Anthony W S

2008-06-01

27

Forced collapse of the blastocoel enhances survival of cryotop vitrified bovine hatching/hatched blastocysts derived from in vitro fertilization and somatic cell nuclear transfer.  

PubMed

Freezing of bovine blastocysts has been widely used to improve the feasibility of cattle production by the embryo transfer technique. However, the low survival of vitrified-warmed embryos and their further development are crucial problems. Particularly, the production of offspring in vitrified-warmed bovine hatching/hatched blastocysts derived from in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) is very low. Thus, we examined the effects of forced blastocoel collapse (FBC) before vitrification of bovine IVF- and SCNT-derived hatching/hatched embryos on the survival rate and apoptosis index after warming. Under optimal conditions, the overall survival rates in vitrified-warmed bovine IVF- and SCNT-derived hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). The total cell numbers of vitrified-warmed hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). Otherwise, the number of apoptotic positive cells of vitrified-warmed hatching/hatched blastocysts was lower in FBC groups than in non-FBC groups (p<0.05). Taken together, these findings suggest that forced collapse of the blastocoel using a pulled Pasteur pipette is an effective pretreatment technique for vitrification of bovine IVF- and SCNT-derived hatching/hatched blastocysts. PMID:23376491

Min, Sung-Hun; Lee, Enok; Son, Hyeong-Hoon; Yeon, Ji-Yeong; Koo, Deog-Bon

2013-01-30

28

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.

2011-01-01

29

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

2013-07-12

30

Different perspectives of patients and health care professionals on the potential benefits and risks of blastocyst culture and multiple embryo transfer  

Microsoft Academic Search

BACKGROUND: A trade-off exists between the risk of multiple pregnancy and prospects of pregnancy itself in assisted reproduction. Blastocyst culture and embryo transfer after ~5 days may be one method of reconciling this dilemma, although a controversial one. METHODS AND RESULTS: We presented a questionnaire to groups of patients, embryologists and clinicians to solicit views on the potential benefits and

G. M. Hartshorne; R. J. Lilford

2002-01-01

31

EFFECT OF ROSCOVITINE OF FIBROBLAST'S ABILITY TO FORM BLASTOCYSTS AND PREGNANCIES AFTER BOVINE NUCLEAR TRANSFER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cloning efficiency of fibroblast nuclear transfer is dependent on donor cell chromatin status. Chromatin status is commonly regulated by serum starvation or contact inhibition. We have tested a third method of synchronizing chromatin activity, roscovitine exposure (in MEM + 10% serum) for 24 h, with...

32

Production of transgenic blastocyst by nuclear transfer from different types of somatic cells in cattle  

Microsoft Academic Search

The present study examined the effects of genetic manipulation to the donor cell and different types of transgenic donor cells\\u000a on developmental potential of bovine nuclear transfer (NT) embryos. Four types of bovine somatic cells, including granulosa\\u000a cells, fetal fibroblasts, fetal oviduct epithelial cells and fetal ovary epithelial cells, were transfected with a plasmid\\u000a (pCE-EGFP-Ires-Neo-dNdB) containing the enhanced green fluorescent

Guochun Gong; Yunping Dai; Baoliang Fan; Huabing Zhu; Haiping Wang; Lili Wang; Changge Fang; Rong Wan; Ying Liu; Rong Li; Ning Li

2004-01-01

33

Caffeine treatment prevents age-related changes in ovine oocytes and increases cell numbers in blastocysts produced by somatic cell nuclear transfer.  

PubMed

Maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) are key regulators of both meiotic and mitotic cycles. Oocytes arrested at metaphase of the second meiotic division (MII) contain high levels of both kinases; however, these activities decline with age. Caffeine (an inhibitor of Myt1/Wee1 activity) can increase MPF and MAPK activities in ovine oocytes; however, the effects of caffeine treatment on the activation, nuclear configuration and developmental potential of ovine SC nuclear transfer (SCNT) embryos were unknown. We examined the effects of aging and caffeine treatment on MPF and MAPK activities, activation, development, and nuclear remodeling of SCNT embryos. Both kinases reached maximum activities at 24-h postonset of maturation (hpm) and then decreased with time. The decline in MPF activity occurred rapidly, whereas MAPK activity declined more slowly. Caffeine treatment (10.0 mM) of aging oocytes prevented the decline in activities associated with both kinases and prevented the acquisition of activation competence by a single activation stimulus. However, treatment of aged oocytes with caffeine could not increase kinase activities or reverse the acquisition of activation competence. Enucleation did not affect kinase activities, but caffeine treatment significantly increased both. Caffeine treatment did not affect the decline in MPF or MAPK activities following activation or significantly affect development of parthenogenetically activated oocytes. When SCNT reconstructed embryos were treated with caffeine following fusion, no increase in the frequency of development to blastocyst was observed; however, a significant increase in the occurrence of nuclear envelope break-down (NEBD) and an increase in total cell numbers occurred. PMID:18673075

Lee, Joon-Hee; Campbell, Keith H S

2008-09-01

34

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

2012-12-27

35

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...

36

Comprehensive chromosome screening of trophectoderm with vitrification facilitates elective single-embryo transfer for infertile women with advanced maternal age.  

PubMed

The universal goal of assisted reproduction technologies is a singleton delivery of a healthy full-term baby. For younger women (<35 years of age) single-embryo transfer is a viable option resulting in clinical success similar to multiple-embryo transfers. In contrast, older women have significantly lower pregnancy rates following single-embryo transfer. To provide effective single-embryo transfer options for older women, improved methods of embryo selection are required to overcome the marked differences in outcome of single- versus double-embryo transfer. With the development of comprehensive chromosome screening, blastocyst vitrification, and trophectoderm biopsy techniques, older women have the opportunity of elective single-embryo transfer with live birth rates as high as those reported for younger good-prognosis infertility patients. PMID:23993664

Schoolcraft, William B; Katz-Jaffe, Mandy G

2013-09-01

37

Changes in the DNA methylation status of bovine embryos from the blastocyst to elongated stage derived from somatic cell nuclear transfer.  

PubMed

The epigenetic reprogramming of the donor cell nucleus is an important factor in the development of embryos and production of normal offspring derived by somatic cell nuclear transfer (NT-SC). During early development, a dramatic reduction in methylation levels occurs in mouse. In early embryos, this process makes it possible to erase gamete-specific methylation patterns and induce de novo methylation at defined developmental time-points. To clarify changes in DNA methylation in bovine NT-SC embryos, we examined satellite I sequences in bovine embryos derived in vivo (Vivo) and by NT-SC at the blastocyst (BC) and elongated (EL) stages. Because the EL stage embryo consists of the embryo disc (ED) and trophectoderm (TE), the methylation status of each part was analyzed with respect to the progress of differentiation. DNA methylation levels in Vivo embryos were increased during the elongation stage. In contrast, DNA methylation levels in NT-SC embryos remained unchanged in the ED and significantly decreased in the TE. Real-time PCR analysis showed that Dnmt-1 expression in BC embryos derived by NT-SC was significantly lower than that in Vivo embryos; thus, differences in the DNA methylation status may reflect transcript levels of Dnmt-1. Our results suggest that the aberrant methylation level of bovine NT-SC embryos in the satellite I region is corrected as a result of demethylation and retention of methylation as the embryo develops and differentiates. PMID:19780699

Sawai, Ken; Takahashi, Masashi; Moriyasu, Satoru; Hirayama, Hiroki; Minamihashi, Akira; Hashizume, Tsutomu; Onoe, Sadao

2010-02-01

38

First polar body morphology and blastocyst formation rate in ICSI patients  

Microsoft Academic Search

BACKGROUND: It may be beneficial to identify, at a very early stage of development, concepti that will result in viable blastocysts by using a non-invasive technique. METHODS: Homogeneous groups in terms of first polar body (PB) morphology were analysed with regard to fertilization, embryo quality and blastocyst formation. The strategy was to transfer a maximum of two blastocysts with an

T. Ebner; M. Moser; M. Sommergruber; C. Yaman; U. Pfleger; G. Tews

2002-01-01

39

Blastocyst microinjection automation.  

PubMed

Blastocyst microinjections are routinely involved in the process of creating genetically modified mice for biomedical research, but their efficiency is highly dependent on the skills of the operators. As a consequence, much time and resources are required for training microinjection personnel. This situation has been aggravated by the rapid growth of genetic research, which has increased the demand for mutant animals. Therefore, increased productivity and efficiency in this area are highly desired. Here, we pursue these goals through the automation of a previously developed teleoperated blastocyst microinjection system. This included the design of a new system setup to facilitate automation, the definition of rules for automatic microinjections, the implementation of video processing algorithms to extract feedback information from microscope images, and the creation of control algorithms for process automation. Experimentation conducted with this new system and operator assistance during the cells delivery phase demonstrated a 75% microinjection success rate. In addition, implantation of the successfully injected blastocysts resulted in a 53% birth rate and a 20% yield of chimeras. These results proved that the developed system was capable of automatic blastocyst penetration and retraction, demonstrating the success of major steps toward full process automation. PMID:19493853

Mattos, Leonardo S; Grant, Edward; Thresher, Randy; Kluckman, Kimberly

2009-05-29

40

Blastocyst Microinjection Automation  

Microsoft Academic Search

Blastocyst microinjections are routinely involved in the process of creating genetically modified mice for biomedical research, but their efficiency is highly dependent on the skills of the operators. As a consequence, much time and resources are required for training microinjection personnel. This situation has been aggravated by the rapid growth of genetic research, which has increased the demand for mutant

Leonardo S. Mattos; Edward Grant; Randy Thresher; Kimberly Kluckman

2009-01-01

41

Single nozzle spray cooling heat transfer mechanisms  

Microsoft Academic Search

An investigation into single nozzle spray cooling heat transfer mechanisms with varying amounts of dissolved gas was performed using two powerful techniques. Time and space resolved heat transfer distributions produced by a single nozzle were measured using an array of individually controlled microheaters, while visualization and measurements of the liquid–solid contact area and the three-phase contact line length were made

Bohumil Horacek; Kenneth T. Kiger; Jungho Kim

2005-01-01

42

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

2013-04-19

43

The effects of 5-aza-2'- deoxycytidine and trichostatin A on gene expression and DNA methylation status in cloned bovine blastocysts.  

PubMed

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; Zhang, Yong

2011-04-12

44

Single embryo transfer with comprehensive chromosome screening results in improved ongoing pregnancy rates and decreased miscarriage rates  

PubMed Central

BACKGROUND Single embryo transfer (SET) provides the most certain means to reduce the risk of multiple gestation. Regrettably, prospective trials of SET have demonstrated reductions in per-cycle delivery rates. A validated method of comprehensive chromosome screening (CCS) has the potential to optimize SET by transferring only euploid embryos. This retrospective study evaluates the efficacy of SET with CCS in an infertile population. METHODS Overall and age-controlled ongoing pregnancy rates (OPR) were compared between women undergoing SET following CCS (CCS-SET, n= 140) and those undergoing SET without aneuploidy screening (control SET, n= 182). All transfers were at the blastocyst stage, with CCS performed after trophectoderm biopsy of expanded blastocysts and analysis with rapid PCR allowing for fresh transfer. RESULTS In the CCS-SET and control SET groups, an OPR of 55.0 and 41.8%, respectively, was obtained. The OPR was lower for the control group (P< 0.01) despite a younger age than the CCS group (37.3 ± 3.4 versus 34.2 ± 3.9 years; P< 0.001). Birthweight and gestational age at delivery were equivalent. The proportion of clinical pregnancies resulting in miscarriage was higher in the control group (24.8 versus 10.5%, P< 0.01), with more patients requiring surgical interventions for aneuploid pregnancies. There was one monozygotic twin delivery in the CCS group and none in the control group. CONCLUSIONS Compared with traditional blastocyst SET, SET after trophectoderm biopsy and rapid PCR-based CCS increases OPR and reduces the miscarriage rate. The enhanced selection empowered by CCS with SET may provide a practical way to eliminate multi-zygotic multiple gestation without compromising clinical outcomes per cycle.

Forman, E.J.; Tao, X.; Ferry, K.M.; Taylor, D.; Treff, N.R.; Scott, R.T.

2012-01-01

45

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

46

Blastocyst cryopreservation using solid surface vitrification: A preliminary study  

PubMed Central

OBJECTIVE: The objective was to evaluate the effectiveness of a blastocyst cryopreservation program using solid surface vitrification. SETTING: This study took place in a university teaching hospital. STUDY DESIGN: Retrospective observational study. MATERIALS AND METHODS: Women undergoing frozen embryo transfer cycles over a 4-year period between 2006 and 2010 were studied. The cryopreservation policy followed was a vitrification protocol performed at the blastocyst stage, using a solid surface (nonimmersion) method. The post-thaw survival rate, implantation rate, clinical pregnancy rate, live birth rate, and neonatal outcome were recorded. RESULTS: Eighty-one women underwent 86 frozen embryo transfer cycles. Of the 240 blastocysts warmed, 204 survived giving a cryosurvival rate of 85% (204/240). The clinical pregnancy, implantation, miscarriage, ongoing pregnancy, and live birth rates per transfer were 47%, 29%, 12%, 16%, and 23% respectively. Of the 20 live births, there were 16 singletons and 4 twins. Eleven boys and 13 girls were delivered with no major or minor abnormality detected. CONCLUSION(S): The blastocyst vitrification protocol using the solid surface method is effective with results comparable to fresh blastocyst transfers. While retaining the rapid cooling effect, the nonimmersion technique eliminates the risk of contamination and disease transmission. Larger studies with long-term follow-up data would further confirm the efficacy and safety of this method of vitrification.

Kamath, Mohan S; Mangalaraj, Ann M; Muthukumar, K; Cullinan, Rosemary; Aleyamma, TK; George, Korula

2011-01-01

47

Trophectoderm biopsy in human blastocysts.  

PubMed

Trophectoderm biopsy was carried out on 47 human blastocysts. A slit was made in the zona pellucida opposite the inner cell mass by micromanipulative techniques. The human blastocyst zona offered more resistance to slitting compared to that of the mouse. After 18-24 h, controlled herniation of the trophectoderm cells was observed. These cells were biopsied when the diameter of the herniation was approximately equal to that of the blastocyst. The size of the slit and the stage of embryonic development at which slitting was performed were important for successful herniation to occur. After slitting, 76% of day 5-6 blastocysts showed herniation whilst only 42% of day 7-8 blastocysts herniated. Further development of the manipulated embryos was not apparently impaired, as hatching occurred in 44% of the former and 20% of the latter, compared with 18.1% in non-manipulated controls. The biopsied cells (approximately 10-30) usually remained in a clump but 14% formed vesicles on the day after biopsy. There was, however, no evidence of adherence to the dish or formation of monolayers. These results demonstrate the feasibility of trophectoderm biopsy in human blastocysts and that sufficient extra-embryonic material can be obtained by this technique for preimplantation diagnosis of genetic disorders. PMID:2266155

Dokras, A; Sargent, I L; Ross, C; Gardner, R L; Barlow, D H

1990-10-01

48

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

49

Single-molecule electron transfer reactions in nanomaterials  

SciTech Connect

Here we report the study of single molecule electron transfer dynamics by coupling fluorescence microscopy at a conventional electrochemical cell. The single-molecule fluorescence spectroelectrochemistry of cresyl violet in aqueous solution and on nanoparticle surface were studied. We observed that the single-molecule fluorescence intensity of cresyl violet is modulated synchronously with the cyclic voltammetric potential scanning. We attribute the fluorescence intensity change of single cresyl violet molecules to the electron transfer reaction driven by the electrochemical potential.

Hu, Dehong; Lei, Chenghong; Ackerman, Eric J.

2009-07-26

50

Induction of cytotoxicity and apoptosis in mouse blastocysts by silver nanoparticles  

Microsoft Academic Search

Silver nanoparticles (nanoAg) are antibacterial materials widely used in various products and medical supplies. In this report, we examined the cytotoxic effects of nanoAg on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, and in vivo implantation by embryo transfer. Blastocysts treated with 50?M nanoAg exhibited significantly increased apoptosis and a corresponding decrease in total

Po-Wn Li; Tai-Hung Kuo; Ji-Hao Chang; Jui-Ming Yeh; Wen-Hsiung Chan

2010-01-01

51

Clinical effectiveness of elective single versus double embryo transfer: meta-analysis of individual patient data from randomised trials  

PubMed Central

Objective To compare the effectiveness of elective single embryo transfer versus double embryo transfer on the outcomes of live birth, multiple live birth, miscarriage, preterm birth, term singleton birth, and low birth weight after fresh embryo transfer, and on the outcomes of cumulative live birth and multiple live birth after fresh and frozen embryo transfers. Design One stage meta-analysis of individual patient data. Data sources A systematic review of English and non-English articles from Medline, Embase, and the Cochrane Central Register of Controlled Trials (up to 2008). Additional studies were identified by contact with clinical experts and searches of bibliographies of all relevant primary articles. Search terms included embryo transfer, randomised controlled trial, controlled clinical trial, single embryo transfer, and double embryo transfer. Review methods Comparisons of the clinical effectiveness of cleavage stage (day 2 or 3) elective single versus double embryo transfer after fresh or frozen in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) treatments were included. Trials were included if the intervention differed only in terms of the intended number of embryos to be transferred. Trials that involved only blastocyst (day five) transfers were excluded. Results Individual patient data were received for every patient recruited to all eight eligible trials (n=1367). A total of 683 and 684 women randomised to the single and double embryo transfer arms, respectively, were included in the analysis. Baseline characteristics in the two groups were comparable. The overall live birth rate in a fresh IVF cycle was lower after single (181/683, 27%) than double embryo transfer (285/683, 42%) (adjusted odds ratio 0.50, 95% confidence interval 0.39 to 0.63), as was the multiple birth rate (3/181 (2%) v 84/285 (29%)) (0.04, 0.01 to 0.12). An additional frozen single embryo transfer, however, resulted in a cumulative live birth rate not significantly lower than the rate after one fresh double embryo transfer (132/350 (38%) v 149/353 (42%) (0.85, 0.62 to 1.15), with a minimal cumulative risk of multiple birth (1/132 (1%) v 47/149 (32%)). The odds of a term singleton birth (that is, over 37 weeks) after elective single embryo transfer was almost five times higher than the odds after double embryo transfer (4.93, 2.98 to 8.18). Conclusions Elective single embryo transfer results in a higher chance of delivering a term singleton live birth compared with double embryo transfer. Although this strategy yields a lower pregnancy rate than a double embryo transfer in a fresh IVF cycle, this difference is almost completely overcome by an additional frozen single embryo transfer cycle. The multiple pregnancy rate after elective single embryo transfer is comparable with that observed in spontaneous pregnancies.

2010-01-01

52

Massively parallel sequencing for chromosomal abnormality testing in trophectoderm cells of human blastocysts.  

PubMed

Preimplantation genetic diagnosis and screening are widely accepted for chromosomal abnormality identification to avoid transferring embryos with genetic defects. Massively parallel sequencing (MPS) is a rapidly developing approach for genome analysis with increasing application in clinical practice. The purpose of this study was to use MPS for identification of aneuploidies and unbalanced chromosomal rearrangements after blastocyst biopsy. Trophectoderm (TE) samples of 38 blastocysts from 16 in vitro fertilization cycles were subjected to analysis. Low-coverage whole genome sequencing was performed using the Illumina HiSeq2000 platform with a novel algorithm purposely created for chromosomal analysis. The efficiency of this MPS approach was estimated by comparing results obtained by an Affymetrix single-nucleotide polymorphism (SNP) array. Whole genome amplification (WGA) products of TE cells were detected by MPS, with an average of 0.07× depth and 5.5% coverage of the human genome. Twenty-six embryos (68.4%) were detected as euploid, while six embryos (15.8%) contained uniform aneuploidies. Four of these (10.5%) were with solely unbalanced chromosomal rearrangements, whereas the remaining two embryos (5.3%) showed both aneuploidies and unbalanced rearrangements. Almost all these results were confirmed by the SNP array, with the exception of one sample, where different sizes of unbalanced rearrangements were detected, possibly due to chromosomal GC bias in array analysis. Our study demonstrated MPS could be applied to accurately detect embryonic chromosomal abnormality with a flexible and cost-effective strategy and higher potential accuracy. PMID:23349234

Yin, XuYang; Tan, Ke; Vajta, Gábor; Jiang, Hui; Tan, YueQiu; Zhang, ChunLei; Chen, Fang; Chen, ShengPei; Zhang, ChunSheng; Pan, XiaoYu; Gong, Chun; Li, XuChao; Lin, ChuYu; Gao, Ya; Liang, Yu; Yi, Xin; Mu, Feng; Zhao, LiJian; Peng, HuanHuan; Xiong, Bo; Zhang, ShuoPing; Cheng, DeHua; Lu, GuangXiu; Zhang, XiuQing; Lin, Ge; Wang, Wei

2013-03-21

53

The human blastocyst: morphology and human chorionic gonadotrophin secretion in vitro.  

PubMed

Micromanipulation of human oocytes and embryos has provided new opportunities for both the treatment of infertility and the preimplantation diagnosis of genetic disease. It is important to determine whether manipulated embryos develop normally in vitro, as an indication of their suitability for transfer. However, at present there is little information on the development of non-manipulated embryos in vitro for comparison. We have therefore monitored morphological changes and human chorionic gonadotrophin (HCG) secretion in 36 non-manipulated human embryos, including 26 blastocysts and 10 cavitating morulae, daily from day 3 to day 14 of culture. Hatching was observed in 10 (38.5%) blastocysts and five of these adhered to the culture dish and appeared viable until day 14. The secretion of HCG was first detected on day 8, peaked at day 10 (51.11 +/- 8.7 mIU/ml) and then declined but was still detectable in four blastocysts on day 14. There was no overall difference in HCG secretion by hatched blastocysts and those which remained within the zona. However, those hatched blastocysts which showed adherence had significantly increased (P less than 0.05) HCG secretion. For individual blastocysts, the pattern of HCG secretion correlated well with the assessment of morphology. These data provide the basis for comparative studies of morphological changes and HCG secretion in manipulated embryos. PMID:1806575

Dokras, A; Sargent, I L; Ross, C; Gardner, R L; Barlow, D H

1991-09-01

54

Successful twin birth following blastocyst culture of embryos derived from the immotile ejaculated spermatozoa from a patient with primary ciliary dyskinesia: A case report  

PubMed Central

Purpose To describe the ultrastructure of spermatozoa from a patient with complete asthenozoospermia that resulted in live births following blastocyst culture. Materials and methods Analyses of spermatozoa from a 36 year old patient were performed using light and electron microscopy. The hypo-osmotic swelling test was used to select spermatozoa for intracytoplasmic sperm injection. Embryos were cultured to the blastocyst stage. Results 100% of the spermatozoa had dynein arm deficiency with secondary defects varying from 3–17%. Six oocytes were injected; five fertilized normally and one was digynic. All five zygotes formed good quality blastocysts. Three blastocysts were cryopreserved and two blastocysts were transferred. Twin females were born at 37 weeks. Conclusions The hypo-osmotic swelling test can be used to select viable immotile ejaculated spermatozoa from a patient with dynein arm deficiency and can produce excellent fertilization rates and blastocyst development resulting in live births.

Price, Robert L.; Davis, Jeffrey M.; Whitman-Elia, Gail F.

2008-01-01

55

Intermittent Single-Molecule Interfacial Electron Transfer Dynamics  

SciTech Connect

We report on single molecule studies of photosensitized interfacial electron transfer (ET) processes in Coumarin 343 (C343)-TiO2 nanoparticle (NP) and Cresyl Violet (CV+)-TiO2 NP systems, using time-correlated single photon counting coupled with scanning confocal fluorescence microscopy. Fluorescence intensity trajectories of individual dye molecules adsorbed on a semiconductor NP surface showed fluorescence fluctuations and blinking, with time constrants distributed from sub-milliseconds to several seconds.

Biju, Vasudevan P.; Micic, Miodrag; Hu, Dehong; Lu, H. Peter

2004-08-04

56

Blastocyst culture in human IVF: the final destination or a stop along the way?  

PubMed

In the field of human IVF, culturing embryos to the blastocyst stage has gained popularity within the past few years. The impetus to transfer blastocysts has been spurred by several factors: 1) the desire to improve implantation rates in infertility patients, 2) a desire to reduce the multiple pregnancy rate by transferring fewer embryos, 3) the desire to perform pre-implantation genetic diagnosis, and 4) the advent of sequential media. Although culturing human embryos to the Hastocyst stage has improved implantation rates and reduced the incidence of multiple pregnancies in some patient populations, it has not worked for all populations of infertility patients. Factors that may affect the ability of a human embryo to reach the blastocyst stage include the patient's age, cohort of ova retrieved, the use of intracytoplasmic sperm injection of blastomere biopsy, culture conditions, or intrinsic factors within the embryo itself. Culture of human embryos to the blastocyst stage can be an effective method for improving implantation rates and reducing the high order multiple pregnancy rates seen in human IVF clinics when more than three embryos are transferred. PMID:11775984

Smith, A L

2002-01-01

57

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

58

Blastocyst development after vitrification of multipronuclear zygotes using the Flexipet denuding pipette  

Microsoft Academic Search

The purpose of this study was to demonstrate the safety and efficacy of vitrification of human pronuclear stage (PN) embryos in the human assisted reproduction laboratory. Using single pronucleate (1PN) and three pronucleate (3PN) zygotes, the impact of vitrification in the Flexipet denuding pipette (FDP) as a carrier was assessed in terms of survival, embryonic development and blastocyst formation when

Juergen Liebermann; Michael J Tucker; James R Graham; Taylor Han; Alana Davis; Michael J Levy

2002-01-01

59

Single nucleon transfer reactions near Coulomb barrier on 197 Au  

Microsoft Academic Search

Summary  Single neutron transfer reactions on 197Au induced by 12C and 16O at near Coulomb barrier energies have been studied using radiochemical and off-line gamma-ray spectrometric techniques. High spin yield fraction (HSF = ?m\\/(?m+?g)) for 196m,gAu and formation cross section ratio (?198\\/?196) of 198Au and 196Au have been determined for both 197Au+12C and 197Au+16O reactions at different excitation energies near the

T. Datta; S. P. Dange; H. Naik

2005-01-01

60

Oxamflatin significantly improves nuclear reprogramming, blastocyst quality, and in vitro development of bovine SCNT embryos.  

PubMed

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

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

2011-08-30

61

Production of calves by transfer of nuclei from cultured inner cell mass cells.  

PubMed Central

We report here the isolation and in vitro culture of bovine inner cell mass (ICM) cells and the use of ICM cells in nuclear transfer to produce totipotent blastocysts that resulted in calves born. Of 15 cell lines represented in this study, 13 were derived from immunosurgically isolated ICM of 3 in vitro produced day 9-10 bovine blastocysts, while 2 lines were derived from single blastocysts. Approximately 70% of attempted cell lines became established cell lines when started from 3 ICMs. The ability to establish cell lines was dependent on the number of ICMs starting the line. Sire differences were noted in the ability of ICMs to establish cell lines and to form blastocysts. The cell lines were cultured as a low cell density suspension in the medium CR1aa plus selenium, insulin, and transferrin (SIT) and 5% fetal calf serum (FCS) for 6-101 days before use in nuclear transfer, at which time some had multiplied to more than 2000 cells. If allowed to aggregate, cells of established cell lines formed embryoid bodies. A total of 659 nuclear transfer clones were made by fusing the ES cells into enucleated oocytes with polyethylene glycol; 460 of these fused, based on cleavage (70%). After culture of the clones for 7 days in vitro in CR1aa/SIT/5% FCS, 109 (24%) of those fused became blastocysts. Thirty-four blastocysts were transferred into uteri of 27 cows, and 13 cows (49%) became pregnant. Four of the 13 cows gave birth to 4 normal calves. DNA typing showed the calves to be derived from the respective sires of the cell lines. The calves were derived from cultures of less than 28 days. Images

Sims, M; First, N L

1994-01-01

62

Evidence of a Pluripotent Human Embryonic Stem Cell Line Derived from a Cloned Blastocyst  

Microsoft Academic Search

Somatic cell nuclear transfer (SCNT) technology has recently been used to generate animals with a common genetic composition. In this study, we report the derivation of a pluripotent embryonic stem (ES) cell line (SCNT-hES-1) from a cloned human blastocyst. The SCNT-hES-1 cells displayed typical ES cell morphology and cell surface markers and were capable of differentiating into embryoid bodies in

Woo Suk Hwang; Young June Ryu; Jong Hyuk Park; Eul Soon Park; Eu Gene Lee; Ja Min Koo; Hyun Yong Jeon; Byeong Chun Lee; Sung Keun Kang; Sun Jong Kim; Curie Ahn; Jung Hye Hwang; Ky Young Park; Jose B. Cibelli; Shin Yong Moon

2004-01-01

63

Derivation of human embryonic stem cell lines after blastocyst microsurgery.  

PubMed

Embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of the blastocyst. Because of their ability to differentiate into a variety of cell types, human embryonic stem cells (hESCs) provide an unlimited source of cells for clinical medicine and have begun to be used in clinical trials. Presently, although several hundred hESC lines are available in the word, only few have been widely used in basic and applied research. More and more hESC lines with differing genetic backgrounds are required for establishing a bank of hESCs. Here, we report the first Canadian hESC lines to be generated from cryopreserved embryos and we discuss how we navigated through the Canadian regulatory process. The cryopreserved human zygotes used in this study were cultured to the blastocyst stage, and used to isolate ICM via microsurgery. Unlike previous microsurgery methods, which use specialized glass or steel needles, our method conveniently uses syringe needles for the isolation of ICM and subsequent hESC lines. ICM were cultured on MEF feeders in medium containing FBS or serum replacer (SR). Resulting outgrowths were isolated, cut into several cell clumps, and transferred onto fresh feeders. After more than 30 passages, the two hESC lines established using this method exhibited normal morphology, karyotype, and growth rate. Moreover, they stained positively for a variety of pluripotency markers and could be differentiated both in vitro and in vivo. Both cell lines could be maintained under a variety of culture conditions, including xeno-free conditions we have previously described. We suggest that this microsurgical approach may be conducive to deriving xeno-free hESC lines when outgrown on xeno-free human foreskin fibroblast feeders. PMID:20555390

Meng, Guoliang; Liu, Shiying; Li, Xiangyun; Krawetz, Roman; Rancourt, Derrick E

2010-06-01

64

Impact of elective single embryo transfer on the twin pregnancy rate  

Microsoft Academic Search

BACKGROUND: It is unclear how the implementation of elective single embryo transfer in clinical practice would affect clinical pregnancy and delivery rates and multiple birth rates. METHODS: This retrospective study analysed 1871 IVF\\/ICSI cycles carried out from 1997 to 2001 in the IVF programme of a single university infertility clinic. RESULTS: The number of elective single embryo transfers increased from

A. Tiitinen; L. Unkila-Kallio; M. Halttunen; C. Hyden-Granskog

2003-01-01

65

Promotion of human early embryonic development and blastocyst outgrowth in vitro using autocrine/paracrine growth factors.  

PubMed

Studies using animal models demonstrated the importance of autocrine/paracrine factors secreted by preimplantation embryos and reproductive tracts for embryonic development and implantation. Although in vitro fertilization-embryo transfer (IVF-ET) is an established procedure, there is no evidence that present culture conditions are optimal for human early embryonic development. In this study, key polypeptide ligands known to be important for early embryonic development in animal models were tested for their ability to improve human early embryo development and blastocyst outgrowth in vitro. We confirmed the expression of key ligand/receptor pairs in cleavage embryos derived from discarded human tri-pronuclear zygotes and in human endometrium. Combined treatment with key embryonic growth factors (brain-derived neurotrophic factor, colony-stimulating factor, epidermal growth factor, granulocyte macrophage colony-stimulating factor, insulin-like growth factor-1, glial cell-line derived neurotrophic factor, and artemin) in serum-free media promoted >2.5-fold the development of tri-pronuclear zygotes to blastocysts. For normally fertilized embryos, day 3 surplus embryos cultured individually with the key growth factors showed >3-fold increases in the development of 6-8 cell stage embryos to blastocysts and >7-fold increase in the proportion of high quality blastocysts based on Gardner's criteria. Growth factor treatment also led to a 2-fold promotion of blastocyst outgrowth in vitro when day 7 surplus hatching blastocysts were used. When failed-to-be-fertilized oocytes were used to perform somatic cell nuclear transfer (SCNT) using fibroblasts as donor karyoplasts, inclusion of growth factors increased the progression of reconstructed SCNT embryos to >4-cell stage embryos. Growth factor supplementation of serum-free cultures could promote optimal early embryonic development and implantation in IVF-ET and SCNT procedures. This approach is valuable for infertility treatment and future derivation of patient-specific embryonic stem cells. PMID:23152897

Kawamura, Kazuhiro; Chen, Yuan; Shu, Yimin; Cheng, Yuan; Qiao, Jie; Behr, Barry; Pera, Renee A Reijo; Hsueh, Aaron J W

2012-11-12

66

Smart Universal Multiple-Valued Logic Gates by Transferring Single Electrons  

Microsoft Academic Search

This paper proposes smart universal multiple-valued (MV) logic gates by transferring single electrons (SEs). The logic gates are based on mosfet based SE turnstiles that can accurately transfer SEs with high speed at high temperature. The number of electrons transferred per cycle by the SE turnstile is a quantized function of its gate voltage, and this characteristic is fully exploited

Wan-Cheng Zhang; Nan-Jian Wu

2008-01-01

67

Photo-Induced Single Molecule Electron Transfer at the Molecule-Nanoparticle Interface  

NASA Astrophysics Data System (ADS)

Single molecule fluorescence spectroscopy was used to study photoinduced electron transfer (ET) dynamics across single donor-bridge-acceptor junctions consisting of perylene-3,4:9,10-bis(dicarboximide) (PDI), n-phenylene bridge with COOH anchoring group, and antimony doped Tin Oxide(ATO) nanoparticles. Photo-excitation of PDI initiates electron transfer from its excited state into ATO nanoparticles. Electron transfer was confirmed and ensemble average rate was measured by transient infrared absorption spectroscopy, in which injected electrons in ATO were directly monitored. Single molecule fluorescence from donor molecule was confirmed by the observed blinking behavior, fluorescence spectrum, and excitation polarization dependence. Single molecule fluorescence lifetime was measured by time-correlated single photon counting, from which forward electron transfer rate from adsorbate excited state to nanoparticle was determined. The dependence of these single molecule ET rates and their fluctuation on the length of phenylene bridge and the nature of semiconductors are being investigated.

Lian, Tianquan; Goh, Wanhee; Guo, Jianchang; Liu, Xi; Ahrens, Michael; Schierloh, Emilie; Wasielewski, Michael

2006-03-01

68

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

2013-03-27

69

Human blastocysts for the development of embryonic stem cells  

Microsoft Academic Search

Establishment of human embryonic stem cells (hES) from surplus human IVF embryos has been successful when both fresh and frozen–thawed cleavage stage embryos have been cultured to the blastocyst stage. This study reports the characteristics of the starting material, the blastocysts, for hES cell lines that were first derived at the University of Gothenburg, Sahlgrenska University Hospital in 1999. Twenty-two

Anita Sjögren; Thorir Hardarson; Katarina Andersson; Gunilla Caisander; Monalill Lundquist; Matts Wikland; Henrik Semb; Lars Hamberger

2004-01-01

70

Development of sheep androgenetic embryos is boosted following transfer of male pronuclei into androgenetic hemizygotes.  

PubMed

Androgenetic embryos are useful model for investigating the contribution of the paternal genome to embryonic development. Little work has been done with androgenetic embryo production in domestic animals. The aim of this study was the production of diploid androgenetic sheep embryos. In vitro matured sheep oocytes were enucleated and fertilized in vitro; parthenogenetic and normally fertilized embryos were also produced as a control. Fifteen hours after in vitro fertilization (IVF), presumptive zygotes were centrifuged and scored for the number of pronucleus. IVF, parthenogenetic, and androgenetic embryos (haploid, diploid, and triploid) were cultured in SOFaa medium with bovine serum albumin (BSA). The proportion of oocytes with polyspermic fertilization increased linearly with increasing sperm concentration. After IVF, there was no significant difference in early cleavage and morula formation rates between the groups, while there was a significant difference on blastocyst development between IVF, parthenogenetic, and androgenetic embryos, the last ones displaying poor developmental potential (IVF, parthenogenetic, and haploid, diploid, and triploid androgenetic embryos: 43%, 38%, 0%, 2%, and 2%, respectively). In order to boost androgenetic embryonic development, we produced diploid androgenetic embryos through pronuclear transfer. Single pronuclei were aspirated with a bevelled pipette from haploid or diploid embryos and transferred into the perivitelline space of other haploid embryos, and the zygotes were reconstructed by electrofusion. Fusion rates approached 100%. Pronuclear transfer significantly increased blastocyst development (IVF, parthenogenetic, androgenetic: Diploid into Haploid, and Haploid into Haploid: 42%, 42%, 19%, and 3%, respectively); intriguingly, the Haploid + Diploid group showed the highest development to blastocyst stage. The main findings of our study are: (1) sheep androgenetic embryos display poor developmental ability compared with IVF and parthenogenetic embryos; (2) diploid androgenetic embryos produced by pronuclear exchange developed in higher proportion to blastocyst stage, particularly in the Diploid-Haploid group. In conclusion, pronuclear transfer is an effective method to produce sheep androgenetic blastocysts. PMID:17907948

Matsukawa, Kazutsugu; Turco, Margherita Yayoi; Scapolo, Pier Augusto; Reynolds, Lawrence; Ptak, Grazyna; Loi, Pasqualino

2007-01-01

71

Bivariate analysis of basal serum anti-M?llerian hormone measurements and human blastocyst development after IVF  

PubMed Central

Background To report on relationships among baseline serum anti-Müllerian hormone (AMH) measurements, blastocyst development and other selected embryology parameters observed in non-donor oocyte IVF cycles. Methods Pre-treatment AMH was measured in patients undergoing IVF (n = 79) and retrospectively correlated to in vitro embryo development noted during culture. Results Mean (+/- SD) age for study patients in this study group was 36.3 ± 4.0 (range = 28-45) yrs, and mean (+/- SD) terminal serum estradiol during IVF was 5929 +/- 4056 pmol/l. A moderate positive correlation (0.49; 95% CI 0.31 to 0.65) was noted between basal serum AMH and number of MII oocytes retrieved. Similarly, a moderate positive correlation (0.44) was observed between serum AMH and number of early cleavage-stage embryos (95% CI 0.24 to 0.61), suggesting a relationship between serum AMH and embryo development in IVF. Of note, serum AMH levels at baseline were significantly different for patients who did and did not undergo blastocyst transfer (15.6 vs. 10.9 pmol/l; p = 0.029). Conclusions While serum AMH has found increasing application as a predictor of ovarian reserve for patients prior to IVF, its roles to estimate in vitro embryo morphology and potential to advance to blastocyst stage have not been extensively investigated. These data suggest that baseline serum AMH determinations can help forecast blastocyst developmental during IVF. Serum AMH measured before treatment may assist patients, clinicians and embryologists as scheduling of embryo transfer is outlined. Additional studies are needed to confirm these correlations and to better define the role of baseline serum AMH level in the prediction of blastocyst formation.

2011-01-01

72

Pair and single neutron transfer with Borromean 8He  

NASA Astrophysics Data System (ADS)

Direct observation of the survival of 199Au residues after 2n transfer in the He8+Au197 system and the absence of the corresponding 67Cu in the He8+Cu65 system at various energies are reported. The measurements of the surprisingly large cross sections for 199Au, coupled with the integral cross sections for the various Au residues, is used to obtain the first model-independent lower limits on the ratio of 2n to 1n transfer cross sections from 8He to a heavy target. A comparison of the transfer cross sections for 6,8He on these targets highlights the differences in the interactions of these Borromean nuclei. These measurements for the most neutron-rich nuclei on different targets highlight the need to probe the reaction mechanism with various targets and represent an experimental advance towards understanding specific features of pairing in the dynamics of dilute nuclear systems.

Lemasson, A.; Navin, A.; Rejmund, M.; Keeley, N.; Zelevinsky, V.; Bhattacharyya, S.; Shrivastava, A.; Bazin, D.; Beaumel, D.; Blumenfeld, Y.; Chatterjee, A.; Gupta, D.; de France, G.; Jacquot, B.; Labiche, M.; Lemmon, R.; Nanal, V.; Nyberg, J.; Pillay, R. G.; Raabe, R.; Ramachandran, K.; Scarpaci, J. A.; Schmitt, C.; Simenel, C.; Stefan, I.; Timis, C. N.

2011-03-01

73

On-Site Array CGH Applications in Clinical In Vitro Fertilization: Reproductive Outcomes and Impact on Cryopreservation of Non-transferred Human Embryos  

PubMed Central

Background: IVF pregnancy rates have trended upward although gains have been accompanied by unwelcome increases in pre-term delivery and multiple gestation. These adverse outcomes happen because multiple embryos are typically transferred during IVF. Integrating newer molecular cytogenetic techniques with IVF can optimize selection of a single embryo for transfer. Methods: The SurePlex DNA amplification system (BlueGnome Ltd; Cambridge, UK) was used on-site for whole genome amplification of human blastocyst trophectoderm (TE) cells obtained by biopsy. IVF patients (initial cycle, age <35, no prior miscarriage, normal karyotype) were prospectively randomized into two groups: In Group 1, embryos were selected on the basis of morphology and comprehensive chromosomal screening via array comparative genomic hybridization (aCGH) from d5 TE biopsy, while Group 2 embryos were assessed by morphology only. All patients underwent a single fresh blastocyst transfer on d6. For embryos in the aCGH group, only one euploid blastocyst was selected for transfer and surplus euploid blastocysts were vitrified. In the non-aCGH (control) group, a single blastocyst was selected for fresh transfer based on appearance only, with vitrification of any surplus blastocysts with satisfactory morphology. Results: Aneuploidy was identified in 191/425 of Group 1 balstocysts (44.9%). Control embryos (n=389) were assessed by microscopy only. A higher clinical pregnancy rate was observed in Group 1 patients compared to the control group (70.9 vs. 45.8%; p = 0.017). Only 64 (28.3%) surplus euploid embryos were frozen in Group 1 while 157 (40.4%) blastocysts were cryopreserved for Group 2 (p=0.017). Conclusion: These data underscore the intrinsic imprecision of IVF when conventional morphology is used alone to select embryos for transfer. Embryos evaluated with aCGH implant with greater efficiency and achieve clinical pregnancy more often than those selected without aCGH. Patients should be advised that aCGH screening may reduce the number of surplus embryos for cryopreservation.

Liu, J.; Salem, S. A.; Peck, A. C.; Yang, Z.; Salem, R. D.; Sills, E. S.

2013-01-01

74

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

75

Ability of tetraploid rat blastocysts to support fetal development after complementation with embryonic stem cells.  

PubMed

This study was undertaken to generate rat offspring via tetraploid blastocyst complementation with embryonic stem (ES) cells. Tetraploid blastocysts were prepared by electrofusion of blastomeres from two-cell stage embryos, and subsequent in vivo culture for 4 days. Microinjection into the tetraploid blastocoel of an inner cell mass isolated by immunosurgery resulted in the generation of rat offspring, suggesting the successful contribution of tetraploid blastocysts to their placenta. Tetraploid blastocyst complementation was attempted with a total of 4 ES cell lines (2 lines of female karyotype and 2 lines of male karyotype). In the rESWIv-3i-5 (XX) cell line, normal-sized fetuses with heartbeats were harvested on E11.5 (12.1%), E12.5 (9.5%), and E13.5 (9.1%), but no viable fetuses were detected on E14.5. Similarly, use of the rESWIv-3i-1 (XX) cell line resulted in no viable fetus production on E14.5. Using the rESBLK2i-1 (XY) cell line, viable fetuses were harvested not only on E11.5-E13.5 (2.6-5.5%), but also on E14.5 (3.0%). The transfer of a total of 487 tetraploid blastocysts complemented with rESBLK2i-1 cells resulted in 256 implantation sites (52.6%) on E21.5, but no viable offspring was detected. Use of the rESBLK2i-1/huKO (XY) cell line also resulted in no viable offspring production on E21.5. Analyses of the methylation pattern in differentially methylated regions and transcript level of genes that are imprinted in mice (H19, Meg3, Igf2r, Peg5, and Peg10) in the E14.5 conceptuses indicated a marked difference between the ES cell-derived and control normal fetuses, but not between the tetraploid and control diploid placenta. PMID:22499253

Hirabayashi, Masumi; Tamura, Chihiro; Sanbo, Makoto; Goto, Teppei; Kato-Itoh, Megumi; Kobayashi, Toshihiro; Nakauchi, Hiromitsu; Hochi, Shinichi

2012-05-04

76

Perceived barriers to elective single embryo transfer among IVF professionals: a national survey  

Microsoft Academic Search

BACKGROUND: After initial years of improvement, the multiple pregnancy rate after in vitro fertilization (IVF) in Europe now remains stable at 23% with single embryo transfer (SET) constituting 19% of all IVF cycles. Although elective SET prevents multiple pregnancies after IVF, couples and professionals apparently often decide to transfer more embryos. Previous qualitative research has identified factors that impede the

A. M. van Peperstraten; R. P. M. G. Hermens; W. L. D. M. Nelen; P. F. M. Stalmeier; G. J. Scheffer; R. P. T. M. Grol; J. A. M. Kremer

2008-01-01

77

Heat transfer to boiling liquids in a single vertical tube thermosiphon reboiler  

Microsoft Academic Search

An experimental investigation of heat transfer to boiling liquids has been carried out on a single tube natural circulation reboiler. Experiments were performed with distilled water, methanol, benzene, toluene, and ethylene glycol to cover a wide range of boiling points and thermophysical properties. The heat transfer section consisted of an electrically heated stainless steel tube 25.56 mm I.D. and 1900

S. S. Alam

1995-01-01

78

Heat transfer to a single explosive particle injected into SCB plasma  

Microsoft Academic Search

This paper is concerned on the interaction of SCB plasma with Lead Azide, Lead Styphnate (LTNR) and Nickel Hydrazine Nitrate (NHN) primary explosive particles, with emphasis on the effects which the heat of explosive imposes on heat transfer from SCB plasma. The heat transfer from SCB plasma to a single spherical particle is calculated by simple calculation method. The effect

Hongyan Feng; Lin Zhang; Shunguan Zhu; Yan Li; Ruiqi Shen

2011-01-01

79

Factors and perceptions that influence women's decisions to have a single embryo transferred  

Microsoft Academic Search

The aim of this study was to identify factors that inhibit or promote the adoption of single embryo transfer (SET). A cohort of 163 women patients receiving IVF\\/intracytoplasmic sperm injection treatment, comprising 87 women choosing SET and 63 women choosing double embryo transfer (DET), were interviewed using a structured questionnaire. The data were compared using logistic regression analysis. Confidence in

S de Lacey; M Davies; G Homan; N Briggs; RJ Norman

2007-01-01

80

Impact of patients' choice for single embryo transfer of a top quality embryo versus double embryo transfer in the first IVF\\/ICSI cycle  

Microsoft Academic Search

BACKGROUND: The aim of this study was to evaluate the impact of transferring a single top quality embryo in the first IVF\\/ICSI cycle of patients 38 years old who chose to have one or two embryos transferred. METHODS: A total of 262 patients participated in the study, and 243 transfers were performed: 156 (64%) patients chose the transfer of a

D. De Neubourg; K. Mangelschots; E. Van Royen; M. Vercruyssen; G. Ryckaert; M. Valkenburg; J. Barudy-Vasquez; J. Gerris

2002-01-01

81

Energy transfer from a single nitrogen-vacancy center in nanodiamond to a graphene monolayer  

NASA Astrophysics Data System (ADS)

In this work, we experimentally demonstrate energy transfer from a single negatively charged nitrogen-vacancy (NV) center in nanodiamond to a graphene monolayer. The mode values of lifetime and intensity of the fluorescence from the single NV center in nanodiamond on monolayer graphene are shorter and weaker than that on bare quartz substrate. The energy transfer efficiency is measured about 40%, consistent with our theoretical estimation.

Liu, Xiaodi; Wang, Guanzhong; Song, Xuerui; Feng, Fupan; Zhu, Wei; Lou, Liren; Wang, Junfeng; Wang, Hong; Bao, Pengfei

2012-12-01

82

Reversible State Transfer between Light and a Single Trapped Atom  

SciTech Connect

We demonstrate the reversible mapping of a coherent state of light with a mean photon number n{approx_equal}1.1 to and from the hyperfine states of an atom trapped within the mode of a high-finesse optical cavity. The coherence of the basic processes is verified by mapping the atomic state back onto a field state in a way that depends on the phase of the original coherent state. Our experiment represents an important step toward the realization of cavity QED-based quantum networks, wherein coherent transfer of quantum states enables the distribution of quantum information across the network.

Boozer, A. D.; Boca, A.; Miller, R.; Northup, T. E.; Kimble, H. J. [Norman Bridge Laboratory of Physics 12-33, California Institute of Technology, Pasadena, California 91125 (United States)

2007-05-11

83

Stress Transfer in Single Fiber\\/ Resin Tensile Tests  

Microsoft Academic Search

Microscale (25 mm gauge length) “dogbone” resin specimens with single carbon fibers embedded through the length of the specimen have been studied as a method for determining the fiber-resin interphase strength. The specimens are pulled in tension until the fiber fragments to a critical length, lc. Evidence is presented here, based primarily on the relaxation of stress birefringence around the

W. D. Bascom; R. M. Jensen

1986-01-01

84

Single-nucleon transfer reactions on (18)F  

SciTech Connect

Simultaneous measurement of the proton-transfer {sup 18}F(d, n){sup 19}Ne and neutron-transfer {sup 18}F(d, p){sup 19}F reactions were performed with a {sup 18}F radioactive beam at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The experiments clarify the nuclear structure of {sup 19}Ne near the proton threshold, which is relevant for understanding the rates of proton-induced reactions on {sup 18}F in novae. Analogs for several states in the mirror nucleus {sup 19}F have not yet been identified in {sup 19}Ne, indicating that the level structure of {sup 19}Ne in this region is incomplete. We observed 15 levels in {sup 19}Ne from the {sup 18}F(d, n){sup 19}Ne measurement and 18 levels in {sup 19}F from the {sup 18}F(d, p){sup 19}F measurement. Angular distributions were extracted for all strongly populated states and compared to distorted-wave Born approximation calculations. The angular distributions for all the known states in the two nuclei determined in this work are consistent with their previously assigned spins and parities. The spectroscopic factors determined for these levels in the two nuclei are reported.

Adekola, A. S. [Ohio University, Athens; Brune, C. R. [Ohio University; Heinen, Z. [Ohio University; Hornish, M. J. [Ohio University; Massey, T. N. [Ohio University; Voinov, A. V. [Ohio University; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Nesaraja, Caroline D [ORNL; Smith, Michael Scott [ORNL; Chae, Kyung Yuk [ORNL; Domizioli, C. [University of Tennessee, Knoxville (UTK); Ma, Z. [University of Tennessee, Knoxville (UTK); Moazen, Brian [University of Tennessee, Knoxville (UTK); Livesay, R. J. [Colorado School of Mines, Golden; Greife, U. [Colorado School of Mines, Golden; Jones, K. L. [Rutgers University; Pain, S. D. [Rutgers University; Thomas, J. S. [Rutgers University; Kozub, R. L. [Tennessee Technological University; ShrinerJr., J. F. [Tennessee Technological University; Smith, N. D. [Tennessee Technological University; Visser, D. W. [University of North Carolina, Chapel Hill

2011-01-01

85

Sodium and chloride co-transport by preimplantation rabbit blastocysts.  

PubMed Central

Influxes of Na+ and Cl- across the trophectodermal epithelium of 6 day post coitum (p.c.) rabbit blastocysts are partially interrelated. This relationship was investigated under conditions in which either the external [Na+] or [Cl-] concentration was varied. Our results indicate that an ouabain-insensitive, furosemide-sensitive, Na+:Cl- co-transport system exists in the 6 and 6.5 day p.c. rabbit embryo, but not in the 5 day p.c. blastocyst. There was no dependence of NaCl uptake on the presence of K+ in the bathing medium. No evidence of Na+/H+ or Cl-/HCO3- exchange systems in the rabbit blastocyst was found. The effects of furosemide, exogenous cyclic AMP, and various exogenous prostaglandins on Na+ and Cl- movements were studied. Cyclic AMP and/or prostaglandin E1 may regulate the operation of this Na+:Cl- co-transport system.

Benos, D J; Biggers, J D

1983-01-01

86

Spin-transfer torque on a single magnetic adatom  

NASA Astrophysics Data System (ADS)

We theoretically show how the spin orientation of a single magnetic adatom can be controlled by spin polarized electrons in a scanning tunnelling microscope configuration. The underlying physical mechanism is spin assisted inelastic tunnelling. Experiments with Mn adatoms deposited on a Cu2N surface have been reported for non-polarized currents [1-2]. We show that by changing the direction of the applied current, the orientation of the magnetic adatom can be completely reversed on a time scale that ranges from a few nanoseconds to microseconds, depending on bias and temperature. The changes in the adatom magnetization direction are, in turn, reflected in the tunnelling conductance. Therefore, this effect opens the possibility of writing/reading a single spin without the need of a local magnetic field.[4pt] [1] C.F. Hirjibehedin, C. P. Lutz, A. J. Heinrich, Science 312, 1021 (2006).[0pt] [2] C. Hirjibehedin et al., Science 317, 1199 (2007).

Delgado, Fernando; José Palacios, Juan; Fernández-Rossier, Joaquín

2010-03-01

87

Heat Transfer Characteristics of an Endwall with Single Row of Oblique Pin Fins  

Microsoft Academic Search

The effect of a single row of oblique pin fins on the endwall heat transfer is investigated experimentally in the two types of pin fin arrangements. One is the ``single row'' arrangement, in which all of the pin fins are inclined toward the same direction and the other is the ``cross row'' arrangement, in which the pin fins are alternately

Ryosuke Matsumoto; Shinzo Kikkawa; Mamoru Senda; Masayuki Suzuki

2001-01-01

88

Blastocyst-mediated induction of endometrial connexins: an inflammatory response?  

PubMed

As a prerequisite for successful embryo implantation in mammals, before implantation ovarian hormones regulate the transformation of the endometrium into the receptive phase. During the implantation process, gene expression in the receptive endometrium is additionally modulated by the presence of a blastocyst. During this complex differentiation process, in humans as well as in rodents, gap junction connexin 26 (Cx26) is suppressed in the uterine epithelium and Cx43 is suppressed in the endometrial stromal cells during the receptive phase. In rodents, a blastocyst-mediated induction of Cx26 takes place locally in the uterine epithelial cells of the implantation chamber surrounding the blastocyst, followed by an increase in Cx43 in the cells of the developing decidua. The Cx26 induction is dependent on the presence of a blastocyst and occurs even before adhesion and invasion of the trophoblast takes place. The signal cascades involved in this blastocyst-mediated connexin induction are still elusive. The process of implantation is considered as a proinflammatory response, and inflammatory factors have been shown to be involved in the implantation process. In fact, Cx26 expression can be induced in the receptive rat endometrium by mediators of the inflammatory cascade including prostaglandin-F2? and IL1? by an ER-independent pathway similar to the blastocyst-mediated connexin induction at the time of implantation. Thus, in the receptive endometrium induction of connexin expression may also be induced by mediators of the inflammatory signaling cascade, and the implantation-related induction of intercellular communication may in part be due to an inflammatory response. PMID:21645927

Grümmer, Ruth; Winterhager, Elke

2011-06-08

89

Limited Asymmetry Dependence of Correlations from Single Nucleon Transfer  

NASA Astrophysics Data System (ADS)

Single nucleon pickup reactions were performed with a 18.1MeV/nucleon O14 beam on a deuterium target. Within the coupled reaction channel framework, the measured cross sections were compared to theoretical predictions and analyzed using both phenomenological and microscopic overlap functions. The missing strength due to correlations does not show significant dependence on the nucleon separation energy asymmetry over a wide range of 37 MeV, in contrast with nucleon removal data analyzed within the sudden-eikonal formalism.

Flavigny, F.; Gillibert, A.; Nalpas, L.; Obertelli, A.; Keeley, N.; Barbieri, C.; Beaumel, D.; Boissinot, S.; Burgunder, G.; Cipollone, A.; Corsi, A.; Gibelin, J.; Giron, S.; Guillot, J.; Hammache, F.; Lapoux, V.; Matta, A.; Pollacco, E. C.; Raabe, R.; Rejmund, M.; de Séreville, N.; Shrivastava, A.; Signoracci, A.; Utsuno, Y.

2013-03-01

90

Conventional freezing of in vitro-produced and biopsied bovine blastocysts in the presence of a low concentration of glycerol and sucrose.  

PubMed

The purpose of this study was to develop a practical cryopreservation method for in vitro-produced (IVP) and sex-predetermined bovine blastocysts that will be applicable to direct transfer of the post-thaw embryos. Blastocysts were harvested 7 days after IVF and allocated to either an intact or biopsy group. The cryoprotective solution contained 0.7 M glycerol and 0, 0.05 or 0.1 M sucrose. Slow cooling at a rate of -0.5 C/min was terminated at -25, -30, or -35 C, and rapid cooling in liquid nitrogen was followed. After one-step thawing and dilution, the IVP blastocysts were cultured for 3 days to assess their survival. The post-thaw survival rate of intact blastocysts after termination of slow cooling at -30 C in 0.7 M glycerol plus 0.1 M sucrose (96.2%) was significantly higher than that at -25 C in 0.7 M glycerol alone (44.4%). The post-thaw survival rate of biopsied bovine blastocysts after termination of slow cooling at -25 C in 0.7 M glycerol alone (53.8%) tended to be lower than that at -25 C in 0.7 M glycerol plus 0.05 M sucrose (91.3%) or -30 C in 0.7 M glycerol plus 0.1 M sucrose (92.3%). Thus, addition of a small amount of sucrose to 0.7 M glycerol cryoprotective solution shortened the process of slow cooling for both the intact and biopsied bovine embryos. Judged from the survival levels in vitro after thawing and one-step dilution of embryos (>80%), this is an improved method of cryopreservation for subsequent direct transfer of IVP and biopsied bovine blastocysts. PMID:17135713

Tominaga, Keiichiro; Iwaki, Fumiyuki; Hochi, Shinichi

2006-11-30

91

Human embryos derived by somatic cell nuclear transfer using an alternative enucleation approach.  

PubMed

Somatic cell nuclear transfer (SCNT) was used to generate patient-specific embryonic stem cells (ESCs) from blastocysts cloned by nuclear transfer (ntESCs). In this study, a total of 135 oocytes were obtained from 12 healthy donors (30-35 years). Human oocytes, obtained within 2 h following transvaginal aspiration, were enucleated using a Spindle Imaging System to position the spindle and chromosomes that lay on the metaphase plate, and a Zona Infrared Laser Optical System was used to open a single hole in the zona pellucida at the ~ 2 o'clock position. Human fibroblasts and lymphocytes were used to construct SCNT embryos. Nearly half (26 of 58) of the oocytes were fused after electrofusion and embryo development rates were 96.2% (two-cell, 25 of 26), 92.3% (four-cell, 24 of 26), 61.5% (eight-cell, 16 of 26), 34.6% (16-cell, 9 of 26), 26.9% (morula, 7 of 26), and 19.2% (blastocyst, 5 of 26), respectively, following incubation in improved G-series sequential medium. One cloned blastocyst was used for STR-DNA identification and genetic polymorphism analysis of mtDNA, and STR-DNA analysis of all cloned blastocysts indicated they were derived from SCNT. Quantitative analysis showed that mtDNA of cloned embryos reflected the change tendency of those observed in human IVF embryos. Our research provides an alternative enucleation approach for producing human SCNT-derived blastocysts, and may aid in providing a new method for human therapeutic cloning. PMID:19196043

Li, Jianyuan; Liu, Xuexia; Wang, Haiyan; Zhang, Shouxin; Liu, Fujun; Wang, Xuebo; Wang, Yanwei

2009-03-01

92

The role of estrogen in uterine receptivity and blastocyst implantation  

Microsoft Academic Search

The endometrium is a specialized, hormonally regulated organ that is non adhesive for embryos throughout most of the reproductive cycle in mammals. Thus, the window of implantation is a self-limited period in which the endometrial epithelium (EE) acquires a functional and transient ovarian steroid-dependent status. The luminal EE initiates the adhesion of the developing blastocyst during this period, owing mainly

Carlos Simon; Francisco Domínguez; Diana Valbuena; Antonio Pellicer

2003-01-01

93

Pluripotency and lineages in the mammalian blastocyst: an evolutionary view.  

PubMed

Early mammalian development is characterized by a highly specific stage, the blastocyst, by which embryonic and extraembryonic lineages have been determined, but pattern formation has not yet begun. The blastocyst is also of interest because cell precursors of the embryo proper retain for a certain time the capability to generate all the cell types of the adult animal. This embryonic pluripotency is established and maintained by a regulatory network under the control of a small set of transcription factors, comprising Oct4, Sox2 and Nanog. This network is largely conserved in eutherian mammals, but there is scarce information about how it arose in vertebrates. We have analysed the conservation of gene regulatory networks controlling blastocyst lineages and pluripotency in the mouse by comparison with the chick. We found that few of elements of the network are novel to mammals; rather, most of them were present before the separation of the mammalian lineage from other amniotes, but acquired novel expression domains during early mammalian development. Our results strongly support the hypothesis that mammalian blastocyst regulatory networks evolved through rewiring of pre-existing components, involving the co-option and duplication of existing genes and the establishment of new regulatory interactions among them. PMID:21527827

Cañon, Susana; Fernandez-Tresguerres, Beatriz; Manzanares, Miguel

2011-06-01

94

Single and Multi-Nucleon Transfer Reactions for Nuclear Moment Studies Toward Radioactive-Ion Beams  

Microsoft Academic Search

This study is a part of an experimental program to measure nuclear moments in transfer reactions. It aims to probe for a first time the nuclear -spin orientation in multi-nucleon transfer. Fist experiments were performed to measure the quadrupole moment of an isomeric state in 66Cu (Ipi = 6-, Ex = 1154 keV, T1\\/2 = 595(20) ns) in single nucleon

R. L. Lozeva; D. L. Balabanski; G. P. Georgiev; G. Audi; A. Blazhev; S. Cabaret; J.-M. Daugas; T. Faul; M. Ferraton; E. Fiori; C. Gaulard; K. Hauschilda; F. Ibrahim; J. Jolie; A. Lopez-Martens; P. Morel; K. Moschner; L. Risegari; O. Roig; S. Szilner; D. Verney; D. T. Yordanov; K.-O. Zell

2010-01-01

95

Single- and double-electron charge transfer in collisions of ?-particles with hydrogen molecules  

NASA Astrophysics Data System (ADS)

Total, partial, and angular differential cross sections of single- and double-electron charge transfer in collisions between ?-particles and hydrogen molecules in the ground state in the interval of collision energies from 3 to 80 keV have been calculated. New data for charge transfer cross sections can be used for simulations and spectroscopy of ?-particles in thermonuclear diverter plasma of nuclear reactors.

Nikulin, V. K.; Gushchina, N. A.; Tsarev, Yu. N.

2013-07-01

96

The single electron transfer chemistry of coals. Final report  

SciTech Connect

This research addressed electron donar properties and radical reactions in coal. Solid residues from pyridine Soxhlet extractions of Pocahontas No. 3, Upper Freeport, Pittsburgh No. 8, Illinois No. 6 and Wyodak coals were exposed to 4-vinylpyridine vapors and swelled. All of the 4-vinylpyridine could not be removed under vacuum at 100{degree}C. Diffuse reflectance FTIR revealed the presence of poly-(4-vinylpyridine) in the Illinois No. 6 and Wyodak coals. EPR spectra displayed the loss of inertinite radicals in Upper Freeport, Illinois No. 6 and Wyodak residues after exposure to 4-vinylpyridine. There was little change in the vitrinite radical density or environment. The molecule N,N{prime}-Diphenyl-p-phenylene diamine (DPPD) was exposed to the solid residues from pyridine Soxhlet extractions of the above coals. Diffuse reflectance FTIR failed to detect the imine product from radical reaction with DPPD. EPR spectra displayed the loss of inertinite radicals in Upper Freeport and Wyodak residues. 7,7,8,8-Tetracyanoquinodimethane (TCNQ) and Tetracyanoethylene (TCNE) were deposited into coals in pyridine. FTIR indicated complete conversion of TCNQ to a material with a singly occupied LUMO. In TCNE the LUMO is about 30% occupied. TCNQ and TCNE were deposited into the pyridine extracts and residues of Illinois No. 6 and Pittsburgh No. 8 coals. Only a small amount of the TCNQ and TCNE displayed nitrile shifts in the IR spectrum of a material with an occupied LUMO. It has been concluded that TCNQ must be part of the aromatic stacks in coal and the TCNQ LUMO is part of an extended band.

Larsen, J.W.; Flowers, R.A. II

1994-12-31

97

Single and double charge transfer of He2+ ions with molecules at near-thermal energies  

NASA Astrophysics Data System (ADS)

Rate coefficients have been measured for charge-transfer reactions of He2+ ions with H2, N2, O2, CO, CO2, and H2O. The experiments were carried out using a selected-ion drift-tube mass spectrometer. Total rate coefficients are found to be very large and are generally close to the limiting Langevin capture rate coefficients or the corresponding ADO coefficients. The product-ion spectra indicate that both single and double charge transfer and possibly transfer ionization occur in these reactions.

Tosh, R. E.; Johnsen, R.

1993-02-01

98

DNA methylation analysis on satellite I region in blastocysts obtained from somatic cell cloned cattle.  

PubMed

Many observations have been made on cloned embryos and on adult clones by somatic cell nuclear transfer (SCNT), but it is still unclear whether the progeny of cloned animals is presenting normal epigenetic status. Here, in order to accumulate the information for evaluating the normality of cloned cattle, we analyzed the DNA methylation status on satellite I region in blastocysts obtained from cloned cattle. Embryos were produced by artificial insemination (AI) to non-cloned or cloned dams using semen from non-cloned or cloned sires. After 7 days of AI, embryos at blastocyst stage were collected by uterine flushing. The DNA methylation levels in embryos obtained by using semen and/or oocytes from cloned cattle were similar to those in in vivo embryos from non-cloned cattle. In contrast, the DNA methylation levels in SCNT embryos were significantly higher (P < 0.01) than those in in vivo embryos from non-cloned and cloned cattle, approximately similar to those in somatic cells used as donor cells. Thus, this study provides useful information that epigenetic status may be normal in the progeny of cloned cattle, suggesting the normality of germline cells in cloned cattle. PMID:21794009

Yamanaka, Ken-Ichi; Kaneda, Masahiro; Inaba, Yasushi; Saito, Koji; Kubota, Kaiyu; Sakatani, Miki; Sugimura, Satoshi; Imai, Kei; Watanabe, Shinya; Takahashi, Masashi

2011-04-20

99

Characterization of human PGD blastocysts with unbalanced chromosomal translocations and human embryonic stem cell line derivation?  

PubMed

Novel embryonic stem cell lines derived from embryos carrying structural chromosomal abnormalities obtained after preimplantation genetic diagnosis (PGD) are of interest to study in terms of the influence of abnormalities on further development. A total of 22 unbalanced blastocysts obtained after PGD were analysed for structural chromosomal defects. Morphological description and chromosomal status of these blastocysts was established and they were used to derive human embryonic stem cell (ESC) lines. An outgrowth of cells was observed for six blastocysts (6/22; 27%). For two blastocysts, the exact morphology was unknown since they were at early stage, and for four blastocysts, the inner cell mass was clearly visible. Fifteen blastocysts carried an unbalanced chromosomal defect linked to a reciprocal translocation, resulting in a positive outgrowth of cells for five blastocysts. One human ESC line was obtained from a blastocyst carrying a partial chromosome-21 monosomy and a partial chromosome-1 trisomy. Six blastocysts carried an unbalanced chromosomal defect linked to a Robertsonian translocation, and one showed a positive outgrowth of cells. One blastocyst carried an unbalanced chromosomal defect linked to an insertion and no outgrowth was observed. The efficiency of deriving human ESC lines with constitutional chromosomal disorders was low and probably depends on the initial morphological aspect of the blastocysts and/or the type of the chromosomal disorders. PMID:20034412

Frydman, N; Féraud, O; Bas, C; Amit, M; Frydman, R; Bennaceur-Griscelli, A; Tachdjian, G

2009-01-01

100

Photovoltaic devices with an active layer from a stamping transfer technique: single layer versus double layer.  

PubMed

In this study, organic photovoltaic devices with single or double-layered active film were prepared from a stamping transfer technique. A P3HT/PCBM single-layered active layer and a ratio-controlled P3HT/PCBM double-layered active can be successfully fabricated with the help of ultraviolet curable polycarbonate films via a stamping transfer technique. The maximum conversion efficiency values 2.85 for a single active layer transferred device and 3.24% for an optimized double active layer transferred device. Even though transferred double layers should have a sharp interface boundary, an intermixed zone with a concentration gradient was generated by the interpenetration of a donor-rich layer and an acceptor-rich layer in a thermal annealing process. The generation of the intermixed zone is confirmed by Auger electron spectroscopy. The enhanced conversion efficiency levels are attributed to the increased efficiency of the carrier transporting process, which is due to the fact that the concentration gradient is combined with the efficient charge generation from the bulk heterojunction layers. PMID:20302275

Wang, Dong Hwan; Choi, Dae-Geun; Lee, Ki-Joong; Park, O Ok; Park, Jong Hyeok

2010-06-15

101

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.

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

2002-01-01

102

Single Molecule Study on the Direct Transfer of E. coli Single-Stranded Binding protein between Single-Stranded DNA Molecules  

NASA Astrophysics Data System (ADS)

Single molecule fluorescence resonance energy transfer (smFRET) techniques allow a direct study of the mechanism of the spontaneous transfer of Escherichia coli Single-Strand Binding (SSB) protein from single-stranded DNA to a competitor single-stand (ss)DNA. This investigation attempts to understand the kinetics of dissociation and ultimately figure out how long can SSB remain bound to ssDNA in midst of competitor free ssDNA. Application of single molecule techniques as described by Taekjip Ha, (Ha. Methods 25, 78--86 (2001)) allow the quantification of the rapid dissociation of SSB from ssDNA as a function of ssDNA length and concentration. We also examined, whether the dissociation occurs with the SSB subunits released simultaneously or consecutively with the possibility of an intermediate state. The variation of dissociation time with DNA length and concentration of the competitive ssDNA demonstrate direct proportionality implying SSB is transferred between ssDNA molecules with a ratio of 1:1, with an abrupt transition from a high FRET state to a low FRET state indicating instantaneous dissociation limited by our time resolution.

Akinyi, Teckla; Lee, I.-Ren; Ha, Taekjip

2013-03-01

103

The transfer of single cell protein technology to the petroleum exporting Arab states  

Microsoft Academic Search

Summary The current status of hydrocarbon and petrochemical based single cell protein (SCP) technologies is assessed with respect to process commercialization. The applicability of such SCP processes for the strategic production of food and feed ingredients in the oil exporting Arab states of the Middle East and North Africa is examined. The possibility of transferring European-developed SCP process technology for

G. Hamer; I. Y. Hamdan

1985-01-01

104

Single-Neutron Transfer Reactions exp 76 Se, exp 78 Se, exp 80 Se,.  

National Technical Information Service (NTIS)

Single neutron transfer reactions on even-even Se nuclei have been studied using 33 MeV incident proton energy from the ANU cyclograaff facility. A total of 120 levels have been seen below 4 MeV excitation energy in exp 75 Se, exp 77 Se, exp 79 Se, exp 81...

L. O. Barbopoulos D. W. Gebbie J. Nurzynski M. Borsaru C. L. Hollas

1979-01-01

105

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

106

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

107

Solution Casting and Transfer Printing Single-Walled Carbon Nanotube Films  

Microsoft Academic Search

This paper presents methods for solution casting and transfer printing collections of individual single-walled carbon nanotubes (SWNTs) onto a wide range of substrates, including plastic sheets. The deposition involves introduction of a solvent that removes surfactant from a suspension of SWNTs as it is applied to a substrate. The subsequent controlled flocculation (cF) produces films of SWNTs with densities that

Matthew A. Meitl; Yangxin Zhou; Anshu Gaur; Seokwoo Jeon; Monica L. Usrey; Michael S. Strano; John A. Rogers

2004-01-01

108

Transfer matrix approach to the statistical mechanics of single polymer molecules  

Microsoft Academic Search

In this work, we demonstrate, implement and critically assess the capabilities and the limitations of the Transfer Matrix (TM) method to the statistical mechanics of single polymer molecules within their classical models. We first show how the TM can be employed with the help of computers, to provide highly accurate results for the configurational statistics of polymers in theta-conditions. We

Lucian Livadaru

2002-01-01

109

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

110

Electron transfer kinetics at single-walled carbon nanotube paper: The role of band structure  

NASA Astrophysics Data System (ADS)

The role of band structure of individual tubules from single-walled carbon nanotube paper in the electron transfer process was considered within Gerischer-Marcus theory using Raman scattering spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy data. A heterogeneous electron transfer rate of 1.06×10-3cms was observed for ferri/ferrocyanid. A position of the Raman radial breathing mode was used for determination of the chiral vectors of tubules being in resonance with excitation laser light of 1.17 eV. For these tubules, the calculated electron transfer rates are similar. It has been shown that nanotube electronic states away from the Fermi level contribute to the electron transfer kinetics due to the broad distribution of the redox states in electrolyte.

Szroeder, Pawe?

2011-11-01

111

Single-scan 2D NMR correlations by multiple coherence transfers  

NASA Astrophysics Data System (ADS)

A new scheme for the acquisition of heteronuclear 2D correlations in NMR spectroscopy within a single scan, is proposed and demonstrated. The principles of this new scheme resemble those of Mansfield’s “k-space walk” proposal, in the sense that they rely on repetitively transferring spin coherences back-and-forth between the two spin systems to be correlated. It is shown that if properly executed, these transfers enable the equivalent of a continuous sampling of the time-domain space supporting a 2D heteronuclear single-quantum correlation NMR spectrum. Details on how to execute the resulting “time-domain walk” experiments are given, and examples comparing it against conventional and other single-scan 2D acquisition alternatives are shown. Advantages, opportunities, and main drawbacks of this new ultrafast approach to 2D NMR, are briefly discussed.

Gal, Maayan; Frydman, Lucio

2010-04-01

112

Effect of genistein on mouse blastocyst development in vitro  

Microsoft Academic Search

Aim:To examine the cytotoxic effects of genistein, an isoflavone compound, on early postimplantation embryonic development in vitro.Methods:Mouse blastocysts were incubated in medium with or without genistein (25 or 50 ?mol\\/L) or daidzein (50 ?mol\\/L) for 24 h. Cell proliferation and growth was investigated by dual differential staining, apoptosis was analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and

Wen-hsiung Chan; Hsiang-yu Lu; Nion-heng Shiao

2007-01-01

113

Derivation of human embryonic stem cell lines from parthenogenetic blastocysts  

Microsoft Academic Search

Parthenogenesis is one of the main, and most useful, methods to derive embryonic stem cells (ESCs), which may be an important source of histocompatible cells and tissues for cell therapy. Here we describe the derivation and characterization of two ESC lines (hPES-1 and hPES-2) from in vitro developed blastocysts following parthenogenetic activation of human oocytes. Typical ESC morphology was seen,

Qingyun Mai; Yang Yu; Tao Li; Liu Wang; Mei-jue Chen; Shu-zhen Huang; Canquan Zhou; Qi Zhou

2007-01-01

114

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa.  

PubMed

Regardless of the presence of sperm-borne oocyte-activating factors, activation of bovine oocytes with exogenous activation stimuli is required for further development after intracytoplasmic sperm injection (ICSI). The current study was designed to develop a new activation regimen for improving the blastocyst yield after ICSI of bovine oocytes harvested from ovaries stored at 10 to 12 degrees C for 24h. After ICSI, oocytes were treated with 5microM ionomycin for 5 min, 7% ethanol for 5 or 10min, ionomycin followed by ethanol (5 or 10 min), ionomycin followed by 10 microg/mL cycloheximide for 5h, or ionomycin followed by 1.9 mM 6-dimethylaminopurine for 3h. Across the activation regimens, the cleavage rates of ICSI oocytes (45% to 77%) were higher than those of parthenogenetically activated oocytes (11% to 21%; P<0.05). Activating the ICSI oocytes with ionomycin plus ethanol improved the blastocyst yield (29% to 30%) compared with that of nontreated oocytes (12%; P<0.05), but the other regimens did not improve the blastocyst yield (9% to 18%; P>0.05). Higher blastocyst yields were due to increasing the proportion of ICSI oocytes that passed through the early postfertilization events until cleavage. None of the regimens have any adverse effect on the quality of the blastocysts regarding the total cell number or the proportion of the inner cell mass cells. Thus, a new activation regimen using two triggers for single calcium increase effectively improved blastocyst yield after bovine ICSI using oocytes harvested from stored ovaries. PMID:19464048

Abdalla, H; Shimoda, M; Hirabayashi, M; Hochi, S

2009-05-21

115

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

2011-09-21

116

Optical-Frequency Transfer over a Single-Span 1840 km Fiber Link  

NASA Astrophysics Data System (ADS)

To compare the increasing number of optical frequency standards, highly stable optical signals have to be transferred over continental distances. We demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of 2×10-15 for a gate time ? of 1 s reaching 4×10-19 in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about 3×10-19. The spectral noise distribution of our fiber link at low Fourier frequencies leads to a ?-2 slope in the modified Allan deviation, which is also derived theoretically.

Droste, S.; Ozimek, F.; Udem, Th.; Predehl, K.; Hänsch, T. W.; Schnatz, H.; Grosche, G.; Holzwarth, R.

2013-09-01

117

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

118

Single Neutron Transfer Experiments Close to the r-Process Path  

SciTech Connect

The first measurements using the (d, p) transfer reaction to study single- particle states in nuclei on the expected r-process path have been made at the Holifield Radioactive Ion Beam Facility. The shell closure at N = 50 has been crossed using the 82Ge(d, p) and 84Se(d, p) reactions. The prop- erties of the lowest-lying states have been determined. Furthermore, the 132Sn(d, p) reaction has been used for the first time to populate single- particle states in 133Sn.

Grzywacz-Jones, Kate L [ORNL; Adekola, Aderemi S [ORNL; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, Kyung Yuk [ORNL; Chipps, K. [Colorado School of Mines, Golden; Cizewski, Jolie [ORNL; Dean, David Jarvis [ORNL; Erikson, Luke [Colorado School of Mines, Golden; Fitzgerald, R. P. [University of North Carolina, Chapel Hill; Gaddis, A. L. [Furman University; Greife, U. [Colorado School of Mines, Golden; Harlin, Christopher W [ORNL; Hatarik, Robert [Rutgers University; Howard, Joshua A [ORNL; Johnson, Micah [ORNL; Kozub, R. L. [Tennessee Technological University; Liang, J Felix [ORNL; Livesay, Jake [ORNL; Ma, Zhanwen [ORNL; Moazen, Brian [University of Tennessee, Knoxville (UTK); O'Malley, Patrick [Rutgers University; Nesaraja, Caroline D [ORNL; Pain, S. D. [Rutgers University; Patterson, N. P. [University of Surrey, UK; Paulauskas, Stanley V [ORNL; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Sissom, D. J. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University

2007-01-01

119

Micro-scale heat transfer mechanisms of single-bubble nucleation events  

NASA Astrophysics Data System (ADS)

The formation, growth and departure of a single bubble at the surface of a heated wall is a fundamental problem which has applications ranging from bubble micropumps and inkjet printers to cooling applications based on boiling heat transfer. The precise prediction of this phenomenon, however, is made difficult by the strong coupling of mass, momentum and energy in the vicinity of a dynamic liquid/vapor interface. Although several important mechanisms (such as microlayer evaporation, transient conduction via surface rewetting and microconvenction from bubble pumping) have been identified over the last half-century, their exact contribution to the bubble growth and overall wall heat transfer has been subject to much debate even in the current literature. In order to quantitatively answer the above question, a novel multi-layer MEMS sensor array has been constructed to obtain high-resolution measurements of surface temperature and heat flux underneath a single bubble within a perfluorcarbon liquid. The result of these measurements has allowed for the detailed description of all three transient mechanisms, and a quantification of their contributions to the bubble growth and heat transfer associated with the ebullition event. Specifically, it is found that convection near the periphery of the bubble interface typically makes the largest contribution to the wall heat transfer at large superheats, followed by rewetting transient conduction and microlayer evaporation, respectively.

Moghaddam, Saeed; Kiger, Ken

2006-11-01

120

Multi-coupled single scattering method of solving vector radiative transfer equations  

NASA Astrophysics Data System (ADS)

A new method of multi-coupled single scattering (MCSS) for solving a vector radiative transfer equation is developed and made public on Internet. Recent solutions from Chandrasekhar's X-Y method is used to validate the MCSS's result, which shows high precision. The MCSS method is theoretically simple and clear, so it can be easily and credibly extended to the simulation of aerosol/cloud atmosphere's radiative properties, which provides effective support for research into polarized remote sensing.

Sun, Bin; Wang, Han; Sun, Xiao-Bing; Hong, Jin; Zhang, Yun-Jie

2012-12-01

121

Fluorescence Quenching of Rhodamine Through Single-Electron Transfer from Trivalent Phosphorus Compounds  

Microsoft Academic Search

Fluorescence from rhodamine 6G in the photoexcited state (Rh *) was quenched by single-electron transfer (SET) from various types of trivalent phosphorus compounds Z3P in aqueous acetonitrile. Dependence of the quenching rate on the oxidation potential of Z3P suggests that the SET from Z3P to Rh * is followed by a rapid reaction of the resulting radical cation Z3P with

Shinro Yasui; Munekazu Tsujimoto; Kenji Itoh; Atsuyoshi Ohno

1999-01-01

122

Visualization of convective boiling heat transfer in single microchannels with different shaped cross-sections  

Microsoft Academic Search

Convective boiling in transparent single microchannels with similar hydraulic diameters but different shaped cross-sections was visualized, along with simultaneous measurement of the local heat transfer coefficient. Two types of microchannels were tested: a circular Pyrex glass microtube (210?m inner diameter) and a square Pyrex glass microchannel (214?m hydraulic diameter). A 100-nm-thick semi-transparent ITO\\/Ag thin film sputtered on the outer wall

Tzu-Hsiang Yen; Masahiro Shoji; Fumio Takemura; Yuji Suzuki; Nobuhide Kasagi

2006-01-01

123

Temperature Dependence of Electron to Lattice Energy-Transfer in Single-Wall Carbon Nanotube Bundles  

Microsoft Academic Search

The electron-phonon coupling strength in single-wall carbon nanotube (SWNT) bundles has been studied directly in the time-domain by femtosecond time-resolved photoelectron spectroscopy. We have measured the dependence of H(T_e,T_l), the rate of energy-transfer between the electronic system and the lattice as a function of electron and lattice temperatures T_e and T_l. The experiments are consistent with a T^5 dependence of

G. Moos; R. Fasel; T. Hertel

2002-01-01

124

Transfer matrix approach to quantum conductivity calculations in single-wall carbon nanotubes  

Microsoft Academic Search

We present an efficient transfer matrix formalism for obtaining the quantum conductivity of single-wall carbon nanotubes (SWCN's) based on a nonorthogonal tight-binding scheme. The formalism is used to calculate conductivity in the presence of topological defects and H adsorbates. I-V characteristics show large oscillatory behavior as a function of the number of H adatoms for both (10,0) and (5,5) SWCN's.

Antonis N. Andriotis; Madhu Menon; Deepak Srivastava

2002-01-01

125

The psychological impact of mild ovarian stimulation combined with single embryo transfer compared with conventional IVF  

Microsoft Academic Search

BACKGROUND: The objective of this study was to assess the psychological implications of mild ovarian stimulation combined with single embryo transfer (SET) during a first IVF cycle. METHODS: We conducted a randomized con- trolled two-centre trial. Three hundred and ninety-one couples were randomized to undergo either mild ovarian stimulation with GnRH antagonist co-treatment and SET (n=199) or conventional GnRH agonist

C. de Klerk; E. M. E. W. Heijnen; N. S. Macklon; H. J. Duivenvoorden; B. C. J. M. Fauser; J. Passchier; J. A. M. Hunfeld

2005-01-01

126

Brief exposure to cycloheximide prior to electrical activation improves in vitro blastocyst development of porcine parthenogenetic and reconstructed embryos.  

PubMed

To investigate the effects of cycloheximide exposure before electrical activation of in vitro-matured porcine oocytes on the subsequent development of parthenogenetic embryos, cumulus-free mature oocytes were exposed to NCSU-23 medium containing cycloheximide (10 microg/mL) for 0, 5, 10, 20, 30 and 60 min, activated by electrical pulse treatment (1.5 kV/cm, 100 micros) and then cultured in PZM-3 for 7 days. To evaluate the effects of cycloheximide on the activation of nuclear transfer embryos, reconstructed embryos were electrically activated by two DC pulses (1.2 kV/cm, 30 micros) before or after exposure to cycloheximide. The reconstructed embryos were allocated into four groups: electrical pulse treatment alone (Ele); exposure to cycloheximide for 10 min followed by electrical activation (CHX+Ele); electrical activation followed by exposure to cycloheximide for 6h (Ele+CHX); exposure to cycloheximide for 10 min, followed by electrical activation and a further exposure to cycloheximide for 6h (CHX+Ele+CHX). The activated reconstructed embryos were cultured in PZM-3 for 6 days. Oocytes treated with 10 min exposure to cycloheximide followed by electrical activation had a significantly higher percentage of blastocyst formation compared to control oocytes and oocytes exposed for > or =30 min. In the reconstructed embryos, the blastocyst development rates of embryos exposed to cycloheximide (CHX+Ele, Ele+CHX and CHX+Ele+CHX) were significantly higher than those of the control group (Ele). Among the cycloheximide-treated groups, the CHX+Ele group had increased development rate and total blastocyst cell number, though these values were not significantly different from those observed in the other cycloheximide-treated groups. To evaluate the quality of NT embryos treated with cycloheximide, apoptosis in blastocysts was analyzed by TUNEL assay. The 10 min exposure to cycloheximide prior to electrical activation significantly reduced cell death compared with longer exposure to cycloheximide after electrical fusion. In conclusion, brief exposure to cycloheximide prior to electrical activation may increase the subsequent blastocyst development rates in porcine parthenogenetic and reconstructed embryos. PMID:17604096

Naruse, K; Quan, Y S; Kim, B C; Lee, J H; Park, C S; Jin, D I

2007-06-29

127

Activation of peroxisome proliferators-activated receptor ? (PPAR?) promotes blastocyst hatching in mice.  

PubMed

Prostaglandins participate in a variety of female reproductive processes, including ovulation, fertilization, embryo implantation and parturition. In particular, maternal prostacyclin (PGI(2)) is critical for embryo implantation and the action of PGI(2) is not mediated via its G-protein-coupled membrane receptor, IP, but its nuclear receptor, peroxisome-proliferator-activated receptor ? (PPAR?). Recently, several studies have shown that PGI(2) enhances blastocyst development and/or hatching rate in vitro, and subsequently implantation and live birth rates in mice. However, the mechanism by which PGI(2) improves preimplantation embryo development in vitro remains unclear. Using molecular, pharmacologic and genetic approaches, we show that PGI(2)-induced PPAR? activation accelerates blastocyst hatching in mice. mRNAs for PPAR?, retinoid X receptor (heterodimeric partners of PPAR?) and PGI(2) synthase (PGIS) are temporally induced after zygotic gene activation, and their expression reaches maximum levels at the blastocyst stage, suggesting that functional complex of PPAR? can be formed in the blastocyst. Carbaprostacyclin (a stable analogue of PGI(2)) and GW501516 (a PPAR? selective agonist) significantly accelerated blastocyst hatching but did not increase total cell number of cultured blastocysts. Whereas U51605 (a PGIS inhibitor) interfered with blastocyst hatching, GW501516 restored U51605-induced retarded hatching. In contrast to the improvement of blastocyst hatching by PPAR? agonists, PPAR antagonists significantly inhibited blastocyst hatching. Furthermore, deletion of PPAR? at early stages of preimplantation mouse embryos caused delay of blastocyst hatching, but did not impair blastocyst development. Taken together, PGI(2)-induced PPAR? activation accelerates blastocyst hatching in mice. PMID:21511721

Kang, Hee Jung; Hwang, Soo Jin; Yoon, Jung Ah; Jun, Jin Hyun; Lim, Hyunjung Jade; Yoon, Tae Ki; Song, Haengseok

2011-04-20

128

A global view of gene expression in the preimplantation mouse embryo: morula versus blastocyst  

Microsoft Academic Search

As a first step to understand preimplantation development, we performed global gene-expression profiling of morula and blastocyst using the NIA 15k mouse cDNA microarray. Gene expression levels were measured four times for blastocyst and five times for morula. Student’s t-test at the 5% significance level identified 428 genes upregulated and 748 downregulated in blastocyst compared to morula. This trend was

Tetsuya S Tanaka; Minoru S. H Ko

2004-01-01

129

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).

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

2013-10-01

130

Blastocyst development from supernumerary embryos after intracytoplasmic sperm injection: a paternal influence?  

PubMed

The success of intracytoplasmic sperm injection (ICSI) warrants further study on the role of paternal factors in early human embryogenesis. To investigate whether poor sperm parameters can influence embryo development, we examined the development of ICSI-fertilized embryos to the blastocyst stage. We present results of blastocyst development from supernumerary ICSI embryos after co-culture on monkey kidney epithelial cells. In addition, we compare the development of supernumerary embryos to the blastocyst stage after ICSI and in-vitro fertilization (IVF). Of 168 supernumerary ICSI embryos, 45 (26.8%) developed to blastocysts. Sperm concentration and morphology did not influence blastocyst development. In contrast, blastocysts arose from spermatozoa that had a significantly higher (P = 0.015) forward progressive motility compared with spermatozoa from those patients who failed to produce blastocysts (42.7% versus 28.2%, respectively). Overall the rate of embryo development to the blastocyst stage after ICSI was lower (26.8%) than that after IVF (47.3%). When the rate of blastocyst development was calculated for patients with three or more supernumerary embryos, it remained significantly higher for the IVF patients than for the ICSI patients (45.6% versus 30.0%). There was no significant difference in the mean cell number and quality of the supernumerary embryos between the IVF and ICSI patients. This study confirms previous reports that have postulated that abnormal spermatozoa may manifest a negative paternal effect on preimplantation embryo development. PMID:9688404

Shoukir, Y; Chardonnens, D; Campana, A; Sakkas, D

1998-06-01

131

Fast electron transfer through a single molecule natively structured redox protein  

NASA Astrophysics Data System (ADS)

The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be `gated' through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with single-molecule conductance values peaking around 18 nS and 12 nS for the SH-SA and SH-LA cytochrome b562 molecules near zero electrochemical overpotential. This strongly points to the important role of the heme co-factor bound to the natively structured protein. We suggest that the two-step model of protein electron transfer in the STM geometry requires a multi-electron transfer to explain such a high conductance. The model also yields a low value for the reorganisation energy, implying that solvent reorganisation is largely absent.The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be `gated' through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with single-molecule conductance values peaking around 18 nS and 12 nS for the SH-SA and SH-LA cytochrome b562 molecules near zero electrochemical overpotential. This strongly points to the important role of the heme co-factor bound to the natively structured protein. We suggest that the two-step model of protein electron transfer in the STM geometry requires a multi-electron transfer to explain such a high conductance. The model also yields a low value for the reorganisation energy, implying that solvent reorganisation is largely absent. Electronic supplementary information (ESI) available: Experimental methods, DNA and protein sequences, additional STM statistical analysis and images, electrochemical data and It-z data analysis. See DOI: 10.1039/c2nr32131a

Della Pia, Eduardo Antonio; Chi, Qijin; MacDonald, J. Emyr; Ulstrup, Jens; Jones, D. Dafydd; Elliott, Martin

2012-10-01

132

Aneuploidy Detection in Pigs Using Comparative Genomic Hybridization: From the Oocytes to Blastocysts  

PubMed Central

Data on the frequency of aneuploidy in farm animals are lacking and there is the need for a reliable technique which is capable of detecting all chromosomes simultaneously in a single cell. With the employment of comparative genomic hybridization coupled with the whole genome amplification technique, this study brings new information regarding the aneuploidy of individual chromosomes in pigs. Focus is directed on in vivo porcine blastocysts and late morulas, 4.7% of which were found to carry chromosomal abnormality. Further, ploidy abnormalities were examined using FISH in a sample of porcine embryos. True polyploidy was relatively rare (1.6%), whilst mixoploidy was presented in 46.8% of embryos, however it was restricted to only a small number of cells per embryo. The combined data indicates that aneuploidy is not a prevalent cause of embryo mortality in pigs.

Hornak, Miroslav; Oracova, Eva; Hulinska, Pavlina; Urbankova, Leona; Rubes, Jiri

2012-01-01

133

Analysis of single phase flow pressure drop and heat transfer in a horizontal rifled tube  

NASA Astrophysics Data System (ADS)

Analysis by using Fluent® has been carried out to investigate the pressure drop and heat transfer of single phase flow (Reynolds number ranging from 2.0×104 - 1.4×105) in a 2 meter long of rifled tube and smooth tube which are heated at the outer wall at constant temperature. The rifled tube or also known as spiral internally ribbed tube which is used in this investigation has an outside diameter 45.0 mm and inside equivalent diameter of 33.1 mm while the smooth tube has an outside diameter 45.0 mm and inside diameter 34.1 mm. The working fluid that is used in this investigation is water. In this analysis, realizable k-epsilon model has been chosen to solve the fully developed turbulence flow in both the tubes. The result from simulation shows that the pressure drop in rifled tube is about 1.69-2.0 times higher than in the smooth tube while the heat transfer coefficient of water in the rifle tube is 0.97-1.27 times than in the smooth tube. The high pressure drop and heat transfer coefficient in rifled tube comparing to smooth tube is due to the helical rib in the rifled tube which not only acted as rough surface, but also causes swirling effect near the wall which enhance heat transfer. The present study has proved that although the rifled tube produces high pressure drop but it is good in heat transfer enhancement through the ratio of heat flux to the pumping power. Correlations have been proposed for the single phase friction factor and Nusselt number of the rifled tube.

Lam, Soo Poey; Wahab, Abas Abdul; Ariffin, Saparudin; Kiow, Lee Woon

2012-06-01

134

Temporal fluctuations of fluorescence resonance energy transfer between two dyes conjugated to a single protein  

NASA Astrophysics Data System (ADS)

Biological molecules together with available labeling chemistries provide an ideal setting to investigate the interaction between two closely spaced dye molecules. The photo-excitation of a donor molecule can be non-radiatively transferred to a near-by acceptor molecule via the induced-dipole-induced-dipole interaction in a distance-dependent manner. In this work, we further elaborate on single-molecule fluorescence resonance energy transfer measurements between two dye molecules attached to a single protein - staphylococcal nuclease molecules [T. Ha, A.Y. Ting, J. Liang, W.B. Caldwell, A.A. Deniz, D.S. Chemla, P.G. Schultz, S. Weiss, Proc. Natl. Acad. Sci. USA 96 (1999) 893-898]. Temporal fluctuations in the energy transfer signal include: (1) reversible transitions to dark states; (2) irreversible photodestruction; (3) intersystem crossing to and from the triplet state; (4) spectral fluctuations; (5) rotational dynamics of the dyes; and (6) distance changes between the two dyes. To extract biologically relevant information from such measurements, an experimental strategy and data analysis schemes are developed. First, abrupt photophysical events, such as (1)-(3) are identified and removed from the data. The remaining slow, gradual fluctuations in the energy transfer signal are due to spectral shifts, rotational dynamics and distance changes of the dyes. Direct measurements of each dye's spectral fluctuation and rotational dynamics indicate that these, by themselves, cannot fully account for the observed energy transfer fluctuations. It is therefore concluded that inter-dye distance changes must be present as well. The distance and orientational dynamics are shown to be dependent on the binding of the active-site inhibitor (deoxythymidine diphosphate) to the protein. The inhibitor most probably affects the protein's stability and the dye-protein interaction, possibly by amplifying the motion of the linker arm between the fluorophore and the protein.

Ha, Taekjip; Ting, Alice Y.; Liang, Joy; Chemla, Daniel S.; Schultz, Peter G.; Weiss, Shimon; Deniz, Ashok A.

1999-08-01

135

Probing the charge-transfer dynamics in DNA at the single-molecule level.  

PubMed

Photoinduced charge-transfer fluorescence quenching of a fluorescent dye produces the nonemissive charge-separated state, and subsequent charge recombination makes the reaction reversible. While the information available from the photoinduced charge-transfer process provides the basis for monitoring the microenvironment around the fluorescent dyes and such monitoring is particularly important in live-cell imaging and DNA diagnosis, the information obtainable from the charge recombination process is usually overlooked. When looking at fluorescence emitted from each single fluorescent dye, photoinduced charge-transfer, charge-migration, and charge recombination cause a "blinking" of the fluorescence, in which the charge-recombination rate or the lifetime of the charge-separated state (?) is supposed to be reflected in the duration of the off time during the single-molecule-level fluorescence measurement. Herein, based on our recently developed method for the direct observation of charge migration in DNA, we utilized DNA as a platform for spectroscopic investigations of charge-recombination dynamics for several fluorescent dyes: TAMRA, ATTO 655, and Alexa 532, which are used in single-molecule fluorescence measurements. Charge recombination dynamics were observed by transient absorption measurements, demonstrating that these fluorescent dyes can be used to monitor the charge-separation and charge-recombination events. Fluorescence correlation spectroscopy (FCS) of ATTO 655 modified DNA allowed the successful measurement of the charge-recombination dynamics in DNA at the single-molecule level. Utilizing the injected charge just like a pulse of sound, such as a "ping" in active sonar systems, information about the DNA sequence surrounding the fluorescent dye was read out by measuring the time it takes for the charge to return. PMID:21875061

Kawai, Kiyohiko; Matsutani, Eri; Maruyama, Atsushi; Majima, Tetsuro

2011-09-12

136

Fast macromolecular proton fraction mapping from a single off-resonance magnetization transfer measurement.  

PubMed

A new method was developed for fast quantitative mapping of the macromolecular proton fraction defined within the two-pool model of magnetization transfer. The method utilizes a single image with off-resonance saturation, a reference image for data normalization, and T(1), B(0), and B(1) maps with the total acquisition time ~10 min for whole-brain imaging. Macromolecular proton fraction maps are reconstructed by iterative solution of the matrix pulsed magnetization transfer equation with constrained values of other model parameters. Theoretical error model describing the variance due to noise and the bias due to deviations of constrained parameters from their actual values was formulated based on error propagation rules. The method was validated by comparison with the conventional multiparameter multipoint fit of the pulsed magnetization transfer model based on data from two healthy subjects and two multiple sclerosis patients. It was demonstrated theoretically and experimentally that accuracy of the method depends on the offset frequency and flip angle of the saturation pulse, and optimal ranges of these parameters are 4-7 kHz and 600°-900°, respectively. At optimal sampling conditions, the single-point method enables <10% relative macromolecular proton fraction errors. Comparison with the multiparameter fitting method revealed very good agreement with no significant bias and limits of agreement around ± 0.7%. PMID:22190042

Yarnykh, Vasily L

2011-12-21

137

Energy transfer in polymer electrophosphorescent light emitting devices with single and multiple doped luminescent layers  

NASA Astrophysics Data System (ADS)

We study energy transfer in efficient polymer electrophosphorescent organic light emitting diodes (PHOLEDs) using poly(9-vinylcarbazole) (PVK) host doped with one or more phosphorescent cyclometalated Ir(III) complexes. Single dopant double heterostructure PHOLEDs exhibited saturated color luminescence due to emissive triplet metal-to-ligand charge-transfer to ground state transitions of the Ir(III) dopants. Blue PHOLEDs, excited by an endothermic process from the host polymer, exhibited an emission maximum at a wavelength of lambdamax=474 nm, with an external quantum efficiency of eta]ext=1.3[plus-or-minus0.1% and luminous power efficiency of eta]p=0.8[plus-or-minus0.1 lm/W. The green PHOLED exhibited eta]ext=5.1[plus-or-minus0.1%, with etaext>2% for both red and yellow emission. Resonant energy transfer between green emitting fac-tris (2-phenylpyridyl)Ir(III) and red emitting bis2-(2')-benzothienyl-pyridinato- N,C3')(acetylacetonate)Ir(III was observed to nearly double the efficiency of red emission when both dopants were simultaneously blended in a PVK host. PHOLEDs containing a blend of red, yellow, and blue Ir(III) complex dopants produced white light emission with eta]ext=2.1[plus-or-minus0.1%. Our results suggest that deep lying energy states in the PVK conductive matrix may limit the energy transfer efficiency in phosphor doped polymer OLEDs.

Kawamura, Yuichiro; Yanagida, Shozo; Forrest, Stephen R.

2002-07-01

138

Doping single-walled carbon nanotubes through molecular charge-transfer: a theoretical study.  

PubMed

We study the effect of the molecular charge transfer on the electronic structure of metallic (5,5) and semiconducting (8,0) single-walled carbon nanotubes (SWNTs) induced by surface adsorption of various organic donor-acceptor molecules of different affinities using ab initio density functional theory. Our results, obtained from first-principles spin-polarized calculations show that the adsorption of molecules with different affinities reflects the difference in interaction strength that measure the overall energy of adsorption. Moderate values of the binding energy of these surface adsorbed molecular charge-transfer complexes suggest that the nature of interaction is in the physisorption regime, and mainly governs by Coulombic forces. We also find that the large band gap of semiconducting (8,0) SWNT can be tuned through the surface adsorption of selective organic molecules which gives rise to mid-gap localized molecular levels near the Fermi energy with tuning of band gap region. Interestingly, we find that the metallic (5,5) SWNT and semiconducting (8,0) SWNT turn into semiconducting and metallic nanotubes respectively in presence of selective surface adsorbed molecules, corroborating recent experimental findings. We also suggest that these charge transfer effect can be probed through optical conductivity measurement, as the low-frequency profiles are affected by charge transfer. PMID:20648348

Manna, Arun K; Pati, Swapan K

2010-04-14

139

Widespread Horizontal Gene Transfer from Circular Single-stranded DNA Viruses to Eukaryotic Genomes  

PubMed Central

Background In addition to vertical transmission, organisms can also acquire genes from other distantly related species or from their extra-chromosomal elements (plasmids and viruses) via horizontal gene transfer (HGT). It has been suggested that phages represent substantial forces in prokaryotic evolution. In eukaryotes, retroviruses, which can integrate into host genome as an obligate step in their replication strategy, comprise approximately 8% of the human genome. Unlike retroviruses, few members of other virus families are known to transfer genes to host genomes. Results Here we performed a systematic search for sequences related to circular single-stranded DNA (ssDNA) viruses in publicly available eukaryotic genome databases followed by comprehensive phylogenetic analysis. We conclude that the replication initiation protein (Rep)-related sequences of geminiviruses, nanoviruses and circoviruses have been frequently transferred to a broad range of eukaryotic species, including plants, fungi, animals and protists. Some of the transferred viral genes were conserved and expressed, suggesting that these genes have been coopted to assume cellular functions in the host genomes. We also identified geminivirus-like and parvovirus-like transposable elements in genomes of fungi and lower animals, respectively, and thereby provide direct evidence that eukaryotic transposons could derive from ssDNA viruses. Conclusions Our discovery extends the host range of circular ssDNA viruses and sheds light on the origin and evolution of these viruses. It also suggests that ssDNA viruses act as an unforeseen source of genetic innovation in their hosts.

2011-01-01

140

A review of heat transfer data for single circular jet impingement  

NASA Astrophysics Data System (ADS)

The paper critically reviews experimental data for the rate of heat transfer from impinging turbulent jets with nozzle exit Reynolds numbers in the range of 5000-124,000. The geometry considered is that of a single circular jet impinging orthogonally onto a plane surface for nozzle-to-plate distances from 1.2-16 nozzle diameters and over a flow region up to six nozzle diameters from the stagnation point. It is suggested that the Nusselt number is independent of nozzle-to-plate spacing up to a value of 12 nozzle diameters to radii greater than six nozzle diameters from the stagnation point. The results from a simple extrapolation for obtaining heat transfer coefficients in the wall jet region compare favorably with published data.

Jambunathan, K.; Lai, E.; Moss, M. A.; Button, B. L.

1992-06-01

141

Kinetics of interfacial electron transfer at single-layer graphene electrodes in aqueous and nonaqueous solutions.  

PubMed

We present a catalog of electron transfer mediators for investigating the heterogeneous electron transfer kinetics of large-area, single-layer graphene electrodes. Scanning electrochemical microscopy (SECM) was used to probe the apparent standard electron transfer rate constant of mediators in aqueous solutions and in acetonitrile and dimethylformamide, allowing for studies of graphene electroactivity at different potentials and in both aqueous and nonaqueous media. In aqueous solution, iron(III) ethylenediaminetetraacetic acid, hexacyanoruthenate(II), hexacyanoferrate(II), hexacyanoferrate(III), octacyanomalybdate(IV), cobalt(III) sepulchrate, and hydroxymethylferrocene exhibited quasi-reversible electron transfer behavior. The electron transfer kinetics of hexaammineruthenium(III), methyl viologen, and tris(2,2'-bipyridyl)ruthenium(II) were found to be reversible in these studies. The electron transfer rate constant of hydroxymethylferrocene and ferrocene, in organic media, was similar to that for hydroxymethylferrocene in water, which, although fast, shows clear kinetic complications that we believe are inherent to graphene. A series of viologens, known to be reversible at metal electrodes, exhibited quasi-reversible electron transfer. For [Co(dapa)(2)](2+), where dapa is 2,6-bis[1-(phenylimino)ethyl]pyridine, in dimethylformamide, the oxidation state of the redox pair investigated affected the observed kinetics. Under similar experimental conditions, the Co(I/II) couple exhibited nearly reversible behavior whereas Co(II/III) had finite kinetics. This behavior was ascribed to the large difference in self-exchange rates for these two processes. To demonstrate the utility of using these mediators for examining graphene electrodes, the kinetics of two mediators with quasi-reversible electron transfer behavior, iron ethylenediaminetetraacetic acid and hexacyanoruthenate, were measured in the presence of a redox-active species [Os(bpy)(2)(dipy)Cl]PF(6), where bpy is 2,2'-bipyridine and dipy is 4,4'-trimethylenedipyridine, adsorbed onto the graphene surface. The kinetics of both mediators were enhanced in the presence of one-hundredth of a monolayer of the osmium complex, showing that even small amounts of impurities on the graphene surface are capable of enhancing the observed kinetics. PMID:23305445

Ritzert, Nicole L; Rodríguez-López, Joaquín; Tan, Cen; Abruña, Héctor D

2013-01-23

142

Universally Distributed Single-Copy Genes Indicate a Constant Rate of Horizontal Transfer  

PubMed Central

Single copy genes, universally distributed across the three domains of life and encoding mostly ancient parts of the translation machinery, are thought to be only rarely subjected to horizontal gene transfer (HGT). Indeed it has been proposed to have occurred in only a few genes and implies a rare, probably not advantageous event in which an ortholog displaces the original gene and has to function in a foreign context (orthologous gene displacement, OGD). Here, we have utilised an automatic method to identify HGT based on a conservative statistical approach capable of robustly assigning both donors and acceptors. Applied to 40 universally single copy genes we found that as many as 68 HGTs (implying OGDs) have occurred in these genes with a rate of 1.7 per family since the last universal common ancestor (LUCA). We examined a number of factors that have been claimed to be fundamental to HGT in general and tested their validity in the subset of universally distributed single copy genes. We found that differing functional constraints impact rates of OGD and the more evolutionarily distant the donor and acceptor, the less likely an OGD is to occur. Furthermore, species with larger genomes are more likely to be subjected to OGD. Most importantly, regardless of the trends above, the number of OGDs increases linearly with time, indicating a neutral, constant rate. This suggests that levels of HGT above this rate may be indicative of positively selected transfers that may allow niche adaptation or bestow other benefits to the recipient organism.

Creevey, Christopher J.; Doerks, Tobias; Fitzpatrick, David A.; Raes, Jeroen; Bork, Peer

2011-01-01

143

77 FR 49837 - Transfer of Outbound Single-Piece First-Class Mail International Packages and Rolls to...  

Federal Register 2010, 2011, 2012, 2013

...transfer would take place in two steps: First, Outbound Single-Piece First-Class Mail International Packages (Small Packets...list; and second, a nearly identical new product, titled ``First-Class Package International Service...

2012-08-17

144

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

2013-07-11

145

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.

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

2013-01-01

146

Characterization of human PGD blastocysts with unbalanced chromosomal translocations and human embryonic stem cell line derivation  

Microsoft Academic Search

Novel embryonic stem cell lines derived from embryos carrying structural chromosomal abnormalities obtained after preimplantation genetic diagnosis (PGD) are of interest to study in terms of the influence of abnormalities on further development. A total of 22 unbalanced blastocysts obtained after PGD were analysed for structural chromosomal defects. Morphological description and chromosomal status of these blastocysts was established and they

N Frydman; O Féraud; C Bas; M Amit; R Frydman; A Bennaceur-Griscelli; G Tachdjian

2009-01-01

147

Oxygen tension and medium type actions on blastocyst development and interferon-tau secretion in cattle  

Microsoft Academic Search

Most current in vitro production systems terminate at the blastocyst stage in cattle. The goal of the present research was to identify culture conditions that support individual blastocyst survival and interferon-tau (IFNT) production in cattle. In the first study, two media (medium 199 [M199] and potassium simplex optimized medium [KSOM]) and two oxygen tensions (5 and 20%) were compared for

Teresa M. Rodina; Flavia N. T. Cooke; Peter J. Hansen; Alan D. Ealy

2009-01-01

148

Estrogen-Dependent Uterine Secretion of Osteopontin Activates Blastocyst Adhesion Competence  

PubMed Central

Embryo implantation is a highly orchestrated process that involves blastocyst-uterine interactions. This process is confined to a defined interval during gestation referred to as the “window of embryo implantation receptivity”. In mice this receptive period is controlled by ovarian estrogen and involves a coordination of blastocyst adhesion competence and uterine receptivity. Mechanisms coordinating the acquisition of blastocyst adhesion competence and uterine receptivity are largely unknown. Here, we show that ovarian estrogen indirectly regulates blastocyst adhesion competence. Acquisition of blastocyst adhesion competence was attributed to integrin activation (e.g. formation of adhesion complexes) rather than de novo integrin synthesis. Osteopontin (OPN) was identified as an estrogen-dependent uterine endometrial gland secretory factor responsible for activating blastocyst adhesion competence. Increased adhesion complex assembly in OPN-treated blastocysts was mediated through focal adhesion kinase (FAK)- and phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways. These findings define for the first time specific regulatory components of an estrogen-dependent pathway coordinating blastocyst adhesion competence and uterine receptivity.

Egashira, Mahiro; Bai, Rulan; Nomura, Nana; Nomura, Shintaro; Hirota, Yasushi; Sakurai, Toshihiro; Imakawa, Kazuhiko

2012-01-01

149

Ultrafast and selective coherent population transfer in four-level atoms by a single nonlinearly chirped femtosecond pulse  

NASA Astrophysics Data System (ADS)

We report a simple scheme to achieve ultrafast and selective population transfer in four-level atoms by utilizing a single nonlinearly chirped femtosecond pulse. It is demonstrated that the almost complete population may be transferred to the preselected state of atoms just by manipulating the so-called frequency offset parameter. The robustness of the scheme against the variation of laser pulse parameters is also investigated. The proposed scheme may be useful for selective population transfer in molecules.

Kumar, Parvendra; Sarma, Amarendra K.

2013-09-01

150

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

151

Observation of Frenkel and charge transfer excitons in pentacene single crystals using spectroscopic generalized ellipsometry  

NASA Astrophysics Data System (ADS)

We report on the emerging and admixture of Frenkel and charge transfer (CT) excitons near the absorption onset in pentacene single crystals. Using high energy-resolution spectroscopic generalized ellipsometry with in-plane polarization dependence, the excitonic nature of three lowest lying excitations is discussed. Their distinct polarization dependence strongly indicates the presence of both Frenkel and CT types of excitons near the excitation onset. In particular, the peculiar polarization behavior of the second excitation can only be rationalized by taking into account the inherent CT transition dipole moment. This observation has important implications for the pentacene-based optoelectronic devices.

Qi, Dongchen; Su, Haibin; Bastjan, M.; Jurchescu, O. D.; Palstra, T. M.; Wee, Andrew T. S.; Rübhausen, M.; Rusydi, A.

2013-09-01

152

Studies of Single-Particle Structure in the N=16 Region Using Transfer Reactions  

SciTech Connect

We have developed a new experimental setup based at the GANIL/SPIRAL facility in Caen, France to measure one-nucleon transfer reactions in inverse kinematics in order to study the evolution of the single particle structure of exotic nuclei. The setup couples together three state-of-the-art detection systems: the TIARA Si array, the large-acceptance magnetic spectrometer VAMOS and the high-efficiency segmented Ge {gamma}-ray array EXOGAM. In a first experiment, the 24Ne(d,p)25Ne reaction has been studied to probe the N=16 shell closure. Details of the setup, data analysis and preliminary results are presented.

Lemmon, R. C.; Pucknell, V. P. E.; Warner, D. D. [CCLRC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom); Fernandez-Dominguez, B.; Chartier, M. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Timis, C.; Catford, W. N.; Baldwin, T. D.; Gelletly, W.; Pain, S. D.; Rejmund, M. [Department of Physics, University of Surrey, Surrey GU2 7XH (United Kingdom); Labiche, M.; Amzal, N.; Burns, M.; Chapman, R.; Liang, X.; Spohr, K. [Institute of Physical Research, University of Paisley, Paisley PA1 2BE (United Kingdom); Ashwood, N.; Curtis, N.; Freer, M. [School of Physics and Astronomy, University of Birmingham B15 2TT (United Kingdom)] (and others)

2006-08-14

153

Mass transfer of a solute by diffusion with convection around a single hollow-fiber membrane for hemodialysis  

Microsoft Academic Search

An apparatus was developed to measure mass transfer rate of a solute through a single hollow-fiber membrane fixed on the axis of a circular tube. Mass transfer rates of three solutes for four hemodialysis membranes were measured with the apparatus at a constant flow rate of a solution in the lumen and at various flow rates of pure water in

Toshiyuki Kanamori; Toshio Shinbo

2000-01-01

154

Electron transfer behaviour of biological macromolecules towards the single-molecule level  

NASA Astrophysics Data System (ADS)

Redox metalloproteins immobilized on metallic surfaces in contact with aqueous biological media are important in many areas of pure and applied sciences. Redox metalloprotein films are currently being addressed by new approaches where biotechnology including modified and synthetic proteins is combined with state-of-the-art physical electrochemistry with emphasis on single-crystal, atomically planar electrode surfaces, in situ scanning tunnelling microscopy (STM) and other surface techniques. These approaches have brought bioelectrochemistry important steps forward towards the nanoscale and single-molecule levels. We discuss here these advances with reference to two specific redox metalloproteins, the blue single-copper protein Pseudomonas aeruginosa azurin and the single-haem protein Saccharomyces cerevisiae yeast cytochrome c, and a short oligonucleotide. Both proteins can be immobilized on Au(111) by chemisorption via exposed sulfur-containing residues. Voltammetric, interfacial capacitance, x-ray photoelectron spectroscopy and microcantilever sensor data, together with in situ STM with single-molecule resolution, all point to a coherent view of monolayer organization with protein electron transfer (ET) function retained. In situ STM can also address the microscopic mechanisms for electron tunnelling through the biomolecules and offers novel notions such as coherent multi-ET between the substrate and tip via the molecular redox levels. This differs in important respects from electrochemical ET at a single metal/electrolyte interface. Similar data for a short oligonucleotide immobilized on Au(111) show that oligonucleotides can be characterized with comparable detail, with novel perspectives for addressing DNA electronic conduction mechanisms and for biological screening towards the single-molecule level.

Zhang, Jingdong; Grubb, Mikala; Hansen, Allan G.; Kuznetsov, Alexander M.; Boisen, Anja; Wackerbarth, Hainer; Ulstrup, Jens

2003-05-01

155

Chiral selectivity in the charge-transfer bleaching of single-walled carbon-nanotube spectra  

NASA Astrophysics Data System (ADS)

Chiral selective reactivity and redox chemistry of carbon nanotubes are two emerging fields of nanoscience. These areas hold strong promise for producing methods for isolating nanotubes into pure samples of a single electronic type, and for reversible doping of nanotubes for electronics applications. Here, we study the selective reactivity of single-walled carbon nanotubes with organic acceptor molecules. We observe spectral bleaching of the nanotube electronic transitions consistent with an electron-transfer reaction occurring from the nanotubes to the organic acceptors. The reaction kinetics are found to have a strong chiral dependence, with rates being slowest for large-bandgap species and increasing for smaller-bandgap nanotubes. The chiral-dependent kinetics can be tuned to effectively freeze the reacted spectra at a fixed chiral distribution. Such tunable redox chemistry may be important for future applications in reversible non-covalent modification of nanotube electronic properties and in chiral selective separations.

O'Connell, Michael J.; Eibergen, Ezra E.; Doorn, Stephen K.

2005-05-01

156

Efficient production of sex-identified and cryosurvived bovine in-vitro produced blastocysts.  

PubMed

To establish a protocol for production of bovine in-vitro produced (IVP) blastocysts that were sex-identified and cryopreserved, we examined the sexing efficiency and accuracy of Day-3 and Day-4 embryos by polymerase chain reaction (PCR), the development of the biopsied embryos into Day-7 blastocysts and the freezability of these blastocysts by vitrification in gel-loading tips. One or two blastomeres were isolated from IVP embryos at either the 8-cell or 16-cell stage (Days 3 and 4, respectively) by a pressing-out method, and were then subjected to primer extension preamplification (PEP)-PCR. The successful sex-identification rate of biopsied samples amplified, purified and analyzed for sex by a second PCR (88.9%) was higher than that of those amplified and analyzed without purification (32.0%). Developmental rates into Day-7 blastocysts of biopsied embryos (Day-3, 65.5%; Day-4, 70.8%) were similar to those of non-biopsied control embryos (Day-3, 74.5%; Day-4, 65.1%). Total cell numbers and the inner cell mass (ICM) ratio of blastocysts derived from biopsied embryos were also comparable with those of control embryos. Blastocysts were vitrified-warmed in the presence of 20% DMSO, 20% ethylene glycol and 0.6M sucrose using gel-loading tips as containers. The proportions of biopsied blastocysts that were hatched or hatching rates after warming were high, regardless of the biopsy time (Day-3, 94.1%; Day-4, 91.9%), similar to the rates for control blastocysts (Day-3, 97.5%; Day-4, 96.9%). In conclusion, a protocol that allows sexing of Day-3 and Day-4 bovine embryos without compromising either the developmental ability to the blastocyst stage or freezability of Day-7 blastocysts was developed. PMID:15037005

Tominaga, Keiichiro; Hamada, Yukako

2004-04-15

157

Communication: Partial polarization transfer for single-scan spectroscopy and imaging  

NASA Astrophysics Data System (ADS)

A method is presented to partially transfer nuclear spin polarization from one isotope S to another isotope I by the way of heteronuclear spin couplings, while minimizing the loss of spin order to other degrees of freedom. The desired I spin polarization to be detected is a design parameter, while the sequence of pulses at the two Larmor frequencies is optimized to store the greatest unused S spin longitudinal polarization for subsequent use. The unitary evolution for the case of INS spin systems illustrates the potentially ideal efficiency of this strategy, which is of particular interest when the spin-lattice relaxation time of S greatly exceeds that of I. Explicit timing and pulses are tabulated for the cases for which M <= 10 partial transfers each result in equal final polarization of 1/M or more compared to the final I polarization expected in a single transfer for N = 1, 2, or 3 I spins. Advantages for the ratiometric study of reacting molecules and hyperpolarized initial conditions are outlined.

Norton, Valerie A.; Weitekamp, Daniel P.

2011-10-01

158

Microcell-mediated transfer of a single human chromosome complements xeroderma pigmentosum group A fibroblasts  

SciTech Connect

Chromosomes from an immortalized aneuploid human fibroblast cell line were randomly tagged with the selectable marker neo by transfection with the plasmid pSV2neo. Somatic cell fusions between transfected human cells and mouse A9 cells generated pools of G418-resistant human-mouse hybrid clones containing various numbers of human chromosomes. Microcell-mediated chromosome transfer from the hybrid pools to xeroderma pigmentosum complementation group A (XP-A) cells in culture and selection for G418-resistant colonies resulted in the identification of XP cells with enhanced resistance to ultraviolet radiation. Screening of subclones from selected pools of human-mouse hybrids facilitated the identification of hybrids containing a single neo-tagged human chromosome. Transfer of this chromosome to XP-A cells (but not to XP-F or XP-C cells) results in enhanced resistance to ultraviolet light and enhanced excision repair capacity. The identification of a single human chromosome that complements the phenotype of XP-A cells in culture provides the potential for genetic mapping of the complementing gene and for its isolation by molecular cloning.

Schultz, R.A.; Saxon, P.J.; Glover, T.W.; Friedberg, E.C.

1987-06-01

159

Shell thickness dependent photoinduced hole transfer in hybrid conjugated polymer/quantum dot nanocomposites: from ensemble to single hybrid level.  

PubMed

Photoinduced hole transfer is investigated in inorganic/organic hybrid nanocomposites of colloidal CdSe/ZnS quantum dots and a cationic conjugated polymer, poly(9,9'-bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-phenylene, in solution and in solid thin film, and down to the single hybrid level and is assessed to be a dynamic quenching process. We demonstrate control of hole transfer rate in these quantum dot/conjugated polymer hybrids by using a series of core/shell quantum dots with varying shell thickness, for which a clear exponential dependency of the hole transfer rate vs shell thickness is observed, for both solution and thin-film situations. Furthermore, we observe an increase of hole-transfer rate from solution to film and correlate this with changes in quantum dot/polymer interfacial morphology affecting the hole transfer rate, namely, the donor-acceptor distance. Single particle spectroscopy experiments reveal fluctuating dynamics of hole transfer at the single conjugated polymer/quantum dot interface and an increased heterogeneity in the hole-transfer rate with the increase of the quantum dot's shell thickness. Although hole transfer quenches the photoluminescence intensity of quantum dots, it causes little or no effect on their blinking behavior over the time scales probed here. PMID:22686521

Xu, Zhihua; Hine, Corey R; Maye, Mathew M; Meng, Qingping; Cotlet, Mircea

2012-06-11

160

HEAT TRANSFER AND VELOCITY CHARACTERISTICS OF SINGLE AND TWO-PHASE FLOWS IN A SUBSONIC MODEL GUN  

Microsoft Academic Search

Heat transfer and velocity measurements are reported for single- and two-phase flows in the wake of an in-bore projectile propelled by an inert gas at an initial gauge pressure of 8 bars to an exit velocity over 40 mis in — 33 ms. The results show that with the single phase the turbulent velocity boundary layers occupy over 20% of

A. F. Bicen; L. KHEZZAR; M. SCHMIDT; J. H. WHITELAW

1989-01-01

161

Derivation of cat embryonic stem-like cells from in vitro-produced blastocysts on homologous and heterologous feeder cells.  

PubMed

The domestic cat is a focal mammalian species that is used as a model for developing assisted reproductive technologies for preserving endangered cats and for studying human diseases. The generation of stable characterized cat embryonic stem cells (ESC) lines to use as donor nuclei may help to improve the efficiency of interspecies somatic cell nuclear transfer for preserving endangered cats and allow the creation of knockout cell lines to generate knockout cats for studying function of specific genes related to human diseases. It will also enable the possibility of producing gametes in vitro from ESC of endangered cats. In the present study, we report the generation of cat embryonic stem-like (cESL) cells from blastocysts derived entirely in vitro. We generated 32 cESL cell lines from 331 in vitro derived blastocysts from which inner cell masses were isolated by immunosurgery or by a mechanical method. Inhibition of cat dermal fibroblast (CDF) proliferation after exposure to mitomycin-C was both dose and time dependent, where doses of 30 to 40 microg/mL for 5 h were most efficient. These dosages were higher than that required to inhibit cell proliferation of mouse fetal fibroblasts (MFF; 10 microg/mL for 2.5 h). Mitomycin-C did not significantly increase necrosis of cells from either species, and had an anti-proliferative effect at concentrations below cytotoxicity. A clear species-specific relationship between feeder layers and derivation of cESL cell lines was observed, where higher numbers of cESL cell lines were generated on homologous cat feeder layers (n = 26) than from those derived on heterologous mouse feeder layers (n = 6). Three cESL cell lines generated from immunosurgery and cultured on CDF maintained self-renewal and were morphologically undifferentiated for nine and twelve passages (69-102 days). These lines showed a tightly packed dome shaped morphology, exhibited alkaline phosphatase activity and immuno-expression of the pluripotent marker OCT-4 and surface marker SSEA-1. Primary colonies at P0 to P3 and cat blastocysts expressed transcription factors OCT-4, NANOG and SOX-2 and the proto-oncogene C-MYC. However, expression was at levels significantly lower than in vitro produced blastocysts. During culture, cESL colonies spontaneously differentiated into fibroblasts, cardiomyocytes, and embryoid bodies. Development of techniques to prevent differentiation of cESL cells will be essential for maintaining defined cell lines. PMID:20708127

Gómez, M C; Serrano, M A; Pope, C Earle; Jenkins, J A; Biancardi, M N; López, M; Dumas, C; Galiguis, J; Dresser, B L

2010-09-01

162

Oxygen affects the ability of mouse blastocysts to regulate ammonium.  

PubMed

During embryo culture, ammonium is generated by amino acid metabolism and from the spontaneous deamination of amino acids at 37°C. Although ammonium has been shown to be embryo toxic, few studies have investigated the mechanism(s) by which the early embryo can regulate ammonium. Whilst 20% oxygen represents a source of stress to the developing embryo, it is not known how oxygen affects the physiology of the embryo in the presence of other sources of stress. The aim of this study was, therefore, to investigate possible pathways involved in ammonium sequestration in the preimplantation embryo and the effect of oxygen on the regulation of these pathways. Glutamine and alanine were investigated as possible ammonium sequestration pathways. Amino acid utilization by blastocysts was determined after culture from the postcompaction stage with 0, 150, or 300 ?M ammonium (in either 5% or 20% oxygen) and with or without 500 ?M L-methionine sulfoximine (MSO), an inhibitor of glutamine synthetase. In the presence of MSO, ammonium production was significantly increased and glutamate was no longer consumed. Glutamine synthetase inhibition with MSO significantly decreased glutamine formation. Ammonium and oxygen independently altered overall amino acid turnover. Together, 5% oxygen and ammonium promoted glutamine production, whereas in the presence of 20% oxygen and ammonium, glutamine was consumed. Data reveal that both oxygen and ammonium affect amino acid utilization by the developing embryo, however, 20% oxygen appears to have the greater impact. Mouse blastocysts can alleviate ammonium stress by its transamination to both glutamine and alanine, but only under physiological conditions. PMID:23803557

Wale, Petra L; Gardner, David K

2013-09-27

163

Nuclear reprogramming in embryos generated by the transfer of yak ( Bos grunniens) nuclei into bovine oocytes and comparison with bovine–bovine SCNT and bovine IVF embryos  

Microsoft Academic Search

Although inter-species SCNT may be useful for increasing and preserving populations of endangered species, there are many reports that inter-species nuclear transfer embryos only develop to the blastocyst stage. In this study, yak–bovine SCNT blastocysts were successfully implanted in the surrogate bovine uterus but failed to develop to term or aborted. To clarify the reasons, we examined yak–bovine SCNT blastocyst

Y. Li; S. Li; Y. Dai; W. Du; C. Zhao; L. Wang; H. Wang; R. Li; Y. Liu; R. Wan; N. Li

2007-01-01

164

A real-life prospective health economic study of elective single embryo transfer versus two-embryo transfer in first IVF\\/ICSI cycles  

Microsoft Academic Search

BACKGROUND: We analysed the difference in maternal, neonatal and total costs after single (SET) versus double day 3 embryo transfer (DET). METHODS: We performed a two-centre prospective study of women in their first IVF\\/ICSI cycle choosing between SET or DET. Infertility treatment data were gathered from a database; maternal and neonatal outcome data from a case report form (CRF); health

J. Gerris; P. De Sutter; D. De Neubourg; E. Van Royen; J. Vander Elst; K. Mangelschots; M. Vercruyssen; P. Kok; M. Elseviers; L. Annemans; P. Pauwels; M. Dhont

2004-01-01

165

Immunolocalization of estrogen receptor protein in the mouse blastocyst during normal and delayed implantation.  

PubMed Central

We previously showed that estrogen receptor (ER) mRNA is present in preimplantation mouse embryos. The apparent synthesis of ER mRNA by the blastocyst at the time of implantation when estrogen is required was of special interest. A demonstration of the presence of ER protein would support the idea that estrogen can act directly on the embryo. The mouse embryo at the blastocyst stage is differentiated into two cell types, the trophectoderm and the inner cell mass. To determine whether ER mRNA is translated into ER protein and its cell-specific distribution, immunocytochemical analyses were performed in mouse blastocysts. ER protein was detected in all cell types of the normal, dormant, or activated blastocyst. To trace the fate of ER in these cell types, immunocytochemistry was performed in implanting blastocysts and early egg cylinder stage embryos developed in culture. Again, ER was detected in all cells of the implanting blastocyst. At the early egg cylinder stage, continued expression of ER was observed in cells derived from the inner cell mass or the trophoblast. In trophoblast giant cells, ER was concentrated in small regions of the nucleus, possibly the nucleoli, which was similar to that observed in dormant and activated blastocysts. The embryonic expression of ER at such early stages in a broad array of cells suggests that ER may have a general role during early development. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Hou, Q; Paria, B C; Mui, C; Dey, S K; Gorski, J

1996-01-01

166

A distribution-based method to resolve single-molecule Förster resonance energy transfer observations  

NASA Astrophysics Data System (ADS)

We introduce a new approach to analyze single-molecule Förster resonance energy transfer (FRET) data. The method recognizes that FRET efficiencies assumed by traditional ensemble methods are unobservable for single molecules. We propose instead a method to predict distributions of FRET parameters obtained directly from the data. Distributions of FRET rates, given the data, are precisely defined using Bayesian methods and increase the information derived from the data. Benchmark comparisons find that the response time of the new method outperforms traditional methods of averaging. Our approach makes no assumption about the number or distribution of underlying FRET states. The new method also yields information about joint parameter distributions going beyond the standard framework of FRET analysis. For example, the running distribution of FRET means contains more information than any conceivable single measure of FRET efficiency. The method is tested against simulated data and then applied to a pilot-study sample of calmodulin molecules immobilized in lipid vesicles, revealing evidence for multiple dynamical states.

Backovi?, Mihailo; Price, E. Shane; Johnson, Carey K.; Ralston, John P.

2011-04-01

167

Epigenetic differences between male and female bovine blastocysts produced in vitro  

Microsoft Academic Search

Abstract Epigenetic differences between male and female bovine blastocysts provide a plausible link between,physiological and gene,transcription differences observed,between,male and female,embryos. The aim,of this study was,to examine,gender-related epigenetic 35 differences in bovine blastocysts produced,in vitro. Oocytes were matured,in vitro and inseminated,with frozen-thawed,sex-sorted (X or Y) and unsorted (control) bull sperm. Zygotes were cultured to blastocyst stage and were analyzed for embryo

P. Bermejo-Alvarez; D. Rizos; D. Rath; P. Lonergan; A. Gutierrez-Adan

2007-01-01

168

Studies of the Single Particle Structure of Exotic Nuclei using Transfer Reactions  

SciTech Connect

The TIARA+VAMOS+EXOGAM set-up has recently been installed at GANIL to study the single-particle structure of exotic nuclei. The unique characteristics of the TIARA array, combined with the large acceptance spectrometer VAMOS and the high efficiency Germanium detector array EXOGAM, has allowed high-resolution measurements of transfer reactions in inverse kinematics using low intensity exotic beams. We will describe the experimental set-up, data analysis and preliminary results of the first experiments using a 24Ne beam from SPIRAL, concentrating in particular on the performance of VAMOS that has been used to detect the heavy fragments after the (d,p) (d,d) and (d,t) reactions.

Fernandez-Dominguez, B.; Chartier, M. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lemmon, R. C.; Pucknell, V. P. E.; Warner, D. D. [CCLRC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Timis, C.; Catford, W. N.; Baldwin, T. D.; Gelletly, W.; Pain, S. D. [Department of Physics, University of Surrey, Surrey GU2 7XH (United Kingdom); Labiche, M.; Amzal, N.; Burns, M.; Chapman, R.; Liang, X.; Spohr, K. [The Institute of Physical Research, University of Paisley, Paisley, PAI 2BE (United Kingdom); Ashwood, N.; Curtis, N.; Freer, M. [School of Physics and Astronomy, University of Birmingham, B15 2TT (United Kingdom); Caballero, L. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain)] (and others)

2006-04-26

169

Conformational fluctuation of Synaptotagmin-1 observed with single molecule fluorescence resonance energy transfer (smFRET)  

NASA Astrophysics Data System (ADS)

Calcium dependent neurotransmitter release at the synapses involves a synaptic vesicle protein synaptotagmin-1, a calcium sensor, to regulate exocytosis. It has been known that Synaptotagmin-1 interacts with assembled SNARE complexes, but it is unclear how their molecular mechanisms are coupled. X-ray studies in the absence of calcium revealed a closed conformation of synaptotagmin-1 and with calcium bound to the C2 domains of synaptotagmin-3 found extensive interactions holding the domains open. Suggesting the two conformations can be the key to the two functions of synaptotagmin in regulating neurotransmission. Here we use single molecule fluorescence resonance energy transfer (smFRET) to study synaptotagmin interactions with SNARE complexes and the spontaneous conformational changes of synaptotagmin-1 when calcium is induced.

Choi, Ucheor; Weninger, Keith

2008-10-01

170

Single-walled carbon nanotubes alter cytochrome c electron transfer and modulate mitochondrial function.  

PubMed

Single-walled carbon nanotubes (SWCNTs) are broadly used for various biomedical applications such as drug delivery, in vivo imaging, and cancer photothermal therapy due to their unique physiochemical properties. However, once they enter the cells, the effects of SWCNTs on the intracellular organelles and macromolecules are not comprehensively understood. Cytochrome c (Cyt c), as a key component of the electron transport chain in mitochondria, plays an essential role in cellular energy consumption, growth, and differentiation. In this study, we found the mitochondrial membrane potential and mitochondrial oxygen uptake were greatly decreased in human epithelial KB cells treated with SWCNTs, which accompanies the reduction of Cyt c. SWCNTs deoxidized Cyt c in a pH-dependent manner, as evidenced by the appearance of a 550 nm characteristic absorption peak, the intensity of which increased as the pH increased. Circular dichroism measurement confirmed the pH-dependent conformational change, which facilitated closer association of SWCNTs with the heme pocket of Cyt c and thus expedited the reduction of Cyt c. The electron transfer of Cyt c is also disturbed by SWCNTs, as measured with electron spin resonance spectroscopy. In conclusion, the redox activity of Cyt c was affected by SWCNTs treatment due to attenuated electron transfer and conformational change of Cyt c, which consequently changed mitochondrial respiration of SWCNTs-treated cells. This work is significant to SWCNTs research because it provides a novel understanding of SWCNTs' disruption of mitochondria function and has important implications for biomedical applications of SWCNTs. PMID:23171082

Ma, Xiaowei; Zhang, Li-Hua; Wang, Li-Rong; Xue, Xue; Sun, Ji-Hong; Wu, Yan; Zou, Guozhang; Wu, Xia; Wang, Paul C; Wamer, Wayne G; Yin, Jun-Jie; Zheng, Kaiyuan; Liang, Xing-Jie

2012-11-29

171

Raman Spectroscopy of Charge Transfer Interactions Between Single Wall Carbon Nanotubes and [FeFe] Hydrogenase  

SciTech Connect

We report a Raman spectroscopy study of charge transfer interactions in complexes formed by single-walled carbon nanotubes (SWNTs) and [FeFe] hydrogenase I (CaHydI) from Clostridium acetobutylicum. The choice of Raman excitation wavelength and sample preparation conditions allows differences to be observed for complexes involving metallic (m) and semiconducting (s) species. Adsorbed CaHydI can reversibly inject electronic charge into the LUMOs of s-SWNTs, while charge can be injected and removed from m-SWNTs at lower potentials just above the Fermi energy. Time-dependent enzymatic assays demonstrated that the reduced and oxidized forms of CaHydI are deactivated by oxygen, but at rates that varied by an order of magnitude. The time evolution of the oxidative decay of the CaHydI activity reveals different time constants when complexed with m-SWNTs and s-SWNTs. The correlation of enzymatic assays with time-dependent Raman spectroscopy provides a novel method by which the charge transfer interactions may be investigated in the various SWNT-CaHydI complexes. Surprisingly, an oxidized form of CaHydI is apparently more resistant to oxygen deactivation when complexed to m-SWNTs rather than s-SWNTs.

Blackburn, J. L. Svedruzic, D.; McDonald, T. J.; Kim, Y. H.; King, P. W.; Heben, M. J.

2008-01-01

172

Energy and Charge State Dependencies of Transfer Ionization and Single Capture  

NASA Astrophysics Data System (ADS)

Investigation of the charge state and energy dependencies of Transfer Ionization (TI) and Single Capture (SC) processes are being completed for Fluorine ions and are being extended to Silicon ions. The collision systems reported here are F^(4-9)+ and Si^(12-14)+ ions interacting with Helium. The measurements are being made for beam energies between 0.5 to 2.5 MeV/u and using a supersonic He jet with two-stage collimation. A recoil ion momentum spectrometer is used to separate TI and SC by recording the longitudinal momentum transfer and time-of-flight of each recoil ion. A magnetic field is used to control the position of the recoil ions on the detector. The ratios of TI to SC are determined with high accuracy. Furthermore, total cross-sections for the bare and hydrogen like Fluorine ions are determined by using previously measured charge exchange cross-sections.^1 SC and TI for higher Z-ions are also under investigation. This work is supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Research, Office of Science, U.S. Department of Energy. *Present address: Institute for Plasma Research, Bhat, Gandhinagar 382428 India [1] T. R. Dillingham, J. R. Macdonald, and P. Richard, Phys. Rev. A 24, 1237 (1981)

Ünal, R.; Richard, P.; Ben-Itzhak, I.; Cocke, C. L.; Singh, M. J.; Tawara, H.; Woody, N.

2001-05-01

173

IS200/IS605 family single-strand transposition: mechanism of IS608 strand transfer  

PubMed Central

Transposase, TnpA, of the IS200/IS605 family member IS608, catalyses single-strand DNA transposition and is dimeric with hybrid catalytic sites composed of an HUH motif from one monomer and a catalytic Y127 present in an ?-helix (?D) from the other (trans configuration). ?D is attached to the main body by a flexible loop. Although the reactions leading to excision of a transposition intermediate are well characterized, little is known about the dynamic behaviour of the transpososome that drives this process. We provide evidence strongly supporting a strand transfer model involving rotation of both ?D helices from the trans to the cis configuration (HUH and Y residues from the same monomer). Studies with TnpA heterodimers suggest that TnpA cleaves DNA in the trans configuration, and that the catalytic tyrosines linked to the 5?-phosphates exchange positions to allow rejoining of the cleaved strands (strand transfer) in the cis configuration. They further imply that, after excision of the transposon junction, TnpA should be reset to a trans configuration before the cleavage required for integration. Analysis also suggests that this mechanism is conserved among members of the IS200/IS605 family.

He, Susu; Guynet, Catherine; Siguier, Patricia; Hickman, Alison B.; Dyda, Fred; Chandler, Mick; Ton-Hoang, Bao

2013-01-01

174

Modeling of heat and mass transfer during thermal decomposition of a single solid fuel particle  

NASA Astrophysics Data System (ADS)

The aim of this work was to investigate the heat and mass transfer during thermal decomposition of a single solid fuel particle. The problem regards the pyrolysis process which occurs in the absence of oxygen in the first stage of fuel oxidation. Moreover, the mass transfer during heating of the solid fuels is the basic phenomenon in the pyrolysis-derived alternative fuels (gas, liquid and solid phase) and in the gasification process which is focused on the generation of syngas (gas phase) and char (solid phase). Numerical simulations concern pyrolysis process of a single solid particle which occurs as a consequence of the particle temperature increase. The research was aimed at an analysis of the influence of particle physical properties on the devolatilization process. In the mathematical modeling the fuel grain is treated as an ideal sphere which consists of porous material (solid and gaseous phase), so as to simplify the final form of the partial differential equations. Assumption that the physical properties change only in the radial direction, reduces the partial derivatives of the angular coordinates. This leads to obtaining the equations which are only the functions of the radial coordinate. The model consists of the mass, momentum and energy equations for porous spherical solid particle heated by the stream of hot gas. The mass source term was determined in the wide range of the temperature according to the experimental data. The devolatilization rate was defined by the Arrhenius formula. The results of numerical simulation show that the heating and devolatilization time strongly depend on the physical properties of fuel. Moreover, proposed model allows to determine the pyrolysis process direction, which is limited by the equilibrium state.

Wardach-?wi?cicka, Izabela; Karda?, Dariusz

2013-06-01

175

Direct spectroscopic evidence of energy transfer from photo-excited semiconducting polymers to single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes have been efficiently dispersed in an organic solvent using the semiconducting polymers MEHPPV and PFO. It has been found that energy is transferred to the carbon nanotubes when the polymer is photo-excited across its minimum energy gap. This is shown using photoluminescence excitation mapping in the range of both the polymer's and the nanotube's optical absorbance. Possible mechanisms for the energy transfer are discussed.

Nish, Adrian; Hwang, Jeong-Yuan; Doig, James; Nicholas, Robin J.

2008-03-01

176

Bovine blastocysts obtained from reconstructed cytoplast and karyoplasts using a simple portable CO2 incubator.  

PubMed

To enable both the multiplication of elite livestock and the engineering of transgenic animals for various agricultural and biochemical purposes, scientists around the world are intensively studying efficient ways of improving developmental competency of bovine embryos reconstructed by somatic cell nuclear transfer. Because it is widely accepted that culture conditions along with many other factors contribute to the developmental competency of reconstructed embryos, this preliminary study was designed to test whether or not bovine reconstructed embryos could develop in vitro using a simple portable CO(2) incubator. CO(2) and O(2) gas tensions and air pressure can be varied using this system. The parameters used in the five conducted trials were low CO(2) (2-5%) and O(2) (8-10%) gas tensions, and negative air pressure (of 300 mm Hg). Chamber temperature was maintained at 38.5 degrees C. Bovine fetal fibroblasts were used as donor karyoplasts and were fused into microsurgically enucleated M II oocytes followed by activation and culture. From the 250 enucleated oocytes, 217 (86.8%) fused, 183 (73.2%) cleaved, and 43 (17.2%) developed to the blastocyst stage. While relatively low developmental rates were achieved, technical proficiency may have been a contributing factor. Further studies using this system are needed to determine optimal levels of O(2), CO(2), and air pressure. PMID:16218853

Varisanga, M D; Dong, Y J; Mtango, N R; Fahrudin, M; Ni Wayan, K K; Suzuki, T

2000-01-01

177

A transferable H2O interaction potential based on a single center multipole expansion: SCME.  

PubMed

A transferable potential energy function for describing the interaction between water molecules is presented. The electrostatic interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability are included. All parameters in the electrostatic interaction as well as the dispersion interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge potentials fitted to liquid water. The evaluation of the new interaction potential for condensed phases is fast because point charges are not present and the interaction can, to a good approximation, be truncated at a finite range. PMID:23949215

Wikfeldt, K T; Batista, E R; Vila, F D; Jónsson, H

2013-08-15

178

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.

Kastantin, Mark; Schwartz, Daniel K.

2011-01-01

179

Radiative heat transfer in fireballs. I. Method for solving the inverse problem for single-body fireballs.  

NASA Astrophysics Data System (ADS)

A method is proposed for determining radiative heat transfer coefficients in the case when a body interacts with a hypersonic flow of rare gas. The method is based on data obtained from two-station photographic observations of fireballs. The method is used to estimate the extent to which the radiative heat transfer coefficients depend on the velocity and density of the gas flow and characteristic dimensions of the body. Essential differences are found between the radiative heat transfer coefficients obtained from observations of Prairie Network single-body fireballs with velocities under 15 km/s and those obtained from model calculations for the radiation-convection interaction in the continuous flow.

Kalenichenko, V. V.

180

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

181

Fine structure of bovine morulae and blastocysts in vivo and in vitro  

Microsoft Academic Search

The ultrastructure of bovine morulae and blastocysts developed from in vitro-matured and -fertilized oocytes in a serum-supplemented\\u000a medium was compared with that of morulae and blastocysts collected non-surgically from superovulated cows. In the in vivo-derived\\u000a morulae, two characteristic cells types could be identified by the electron-density of their cytoplasm and by their ultrastructural\\u000a features. One type appeared light in color

H. Abe; T. Otoi; S. Tachikawa; S. Yamashita; T. Satoh; H. Hoshi

1999-01-01

182

Cross-validation of techniques for measuring lipid content of bovine oocytes and blastocysts  

Microsoft Academic Search

The main objective was to test and validate a fluorescence approach to quantify lipid content of individual bovine oocytes and blastocysts. For Experiment 1, denuded oocytes were evaluated, as well as in vitro-produced blastocysts in a factorial design: cows versus feedlot heifers; three additives during Days 2.5–7.5 of culture (Control; 10% FCS; 0.3 ?M phenazine ethosulfate (PES), an electron acceptor

M. Barceló-Fimbres; G. E. Seidel

2011-01-01

183

GLUT8 is a glucose transporter responsible for insulin-stimulated glucose uptake in the blastocyst  

Microsoft Academic Search

Mammalian preimplantation blastocysts exhibit insulin-stimulated glucose uptake despite the absence of the only known insulin-regulated transporter, GLUT4. We describe a previously unidentified member of the mammalian facilitative GLUT superfamily that exhibits 20-25% identity with other murine facilitative GLUTs. Insulin induces a change in the intracellular localization of this protein, which translates into increased glucose uptake into the blastocyst, a process

Mary O. Carayannopoulos; Maggie M.-Y. Chi; Ying Cui; Joyce M. Pingsterhaus; Robert A. McKnight; Mike Mueckler; Sherin U. Devaskar; Kelle H. Moley

2000-01-01

184

Influence of advanced age on the blastocyst development rate and pregnancy rate in assisted reproductive technology  

Microsoft Academic Search

Objective: To evaluate the percentage of blastocysts developing, the pregnancy rate, the implantation rate, and the abortion rate in women >40 years of age using a cell-free culture system for the development of viable human blastocysts.Design: Retrospective clinical study.Setting: Private IVF units.Patient(s): Two hundred ninety-three cycles in patients undergoing IVF treatment for infertility. Sixty-two cycles were in patients ?40 years

Kostas Pantos; Vasilis Athanasiou; Konstantinos Stefanidis; Dimitris Stavrou; Terpsi Vaxevanoglou; Margarita Chronopoulou

1999-01-01

185

Single-molecule fluorescence resonance energy transfer in nanopipets: improving distance resolution and concentration range.  

PubMed

In recent years fluorescence resonance energy transfer (FRET) has widely been used to measure distances, binding, and distance dynamics at the single-molecule (sm) level. Some basic constraints of smFRET are the limited distance resolution owing to low photon statistics and the restriction to high affinity interactions. We demonstrate that by confining molecules in nanopipets with an inner diameter of approximately 100 nm at the tip, FRET can be measured with improved photon statistics and at up to 50-fold higher concentrations. The flow of the donor/acceptor (Cy3B/ATTO647N) labeled double-stranded DNA conjugates was established by electrokinetic forces. Because of the small inner diameter of the nanopipet, every molecule passing the tip is detected applying alternating laser excitation (ALEX). Thus, the technique offers the advantage to study interactions with smaller association constants (<10(9) M-1) using minute sample amounts (<5 microL). The improved photon statistics reduces shot-noise contributions and results in sharper FRET distributions. Experimental results are supported by Monte Carlo simulations which also explain the occurrence of two populations in burst size distributions measured in nanopipet experiments. Because of the confinement of the molecules in nanopipets, the widths of FRET histograms are reduced to a degree where shot-noise is not the only limiting factor but also conformational dynamics of the linkers used to attach the chromophores have to be considered. In addition, our experiments emphasize the influence of photoinduced dark states on both the mean energy transfer efficiency and the width of FRET histograms. PMID:17822310

Vogelsang, Jan; Doose, Sören; Sauer, Markus; Tinnefeld, Philip

2007-09-07

186

Single-embryo transfer reduces clinical pregnancy rates and live births in fresh IVF and Intracytoplasmic Sperm Injection (ICSI) cycles: a meta-analysis  

Microsoft Academic Search

BACKGROUND: It has become an accepted procedure to transfer more than one embryo to the patient to achieve acceptable ongoing pregnancy rates. However, transfers of more than a single embryo increase the probability of establishing a multiple gestation. Single-embryo transfer can minimize twin pregnancies but may also lower live birth rates. This meta-analysis aimed to compare current data on single-embryo

Ricardo LR Baruffi; Ana L Mauri; Claudia G Petersen; Andréia Nicoletti; Anagloria Pontes; João Batista A Oliveira; José G Franco Jr

2009-01-01

187

Detection of single-nucleotide variations by monitoring the blinking of fluorescence induced by charge transfer in DNA.  

PubMed

Charge transfer dynamics in DNA: Photo-induced charge separation and charge-recombination dynamics in DNA was assessed by monitoring the blinking of fluorescence. Single nucleotide variations, mismatch and one base deletion, were differentiated based on the length of the off-time of the blinking, which corresponds to the lifetime of the charge-separated state. PMID:23846860

Kawai, Kiyohiko; Majima, Tetsuro; Maruyama, Atsushi

2013-07-11

188

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 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

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

2011-01-01

189

Generation of single entangled photon pair state from a semiconductor quantum dot and development of quantum image transfer technology  

Microsoft Academic Search

In this research program, we aimed : 1) to develop a semiconductor source that emits a single entangled photon pair, and 2) to develop a novel scheme for quantum image transfer utilizing quantum correlations between entangled photons. We have developed the first entangled photon source utilizing biexciton-resonant hyper parametric scattering in a semiconductor (CuCl) crystal. We also developed a novel

Keiichi Edamatsu; Yasuyoshi Mitsumori; Tadashi Itoh

190

Performance analysis and optimization of a single barrier solid-state thermionic refrigerator with external heat transfer  

Microsoft Academic Search

A model of a single barrier solid-state thermionic refrigerator with external heat transfer is established in this paper. The performance of the refrigerator is analyzed and optimized by using the combination of finite time thermodynamics and non-equilibrium thermodynamics. The general expressions for cooling load and coefficient of performance (COP) of the refrigerator are derived. The optimum regions of cooling load

ZE-MIN DING; LIN-GEN CHEN; FENG-RUI SUN

2012-01-01

191

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

192

Single-collision studies of hot atom energy transfer and chemical reaction. Final report  

SciTech Connect

This report discusses research in the collision dynamics of translationally hot atoms, with funding with DOE for the project ``Single-Collision Studies of Hot Atom Energy Transfer and Chemical Reaction,`` Grant Number DE-FG03-85ER13453. The work reported here was done during the period September 9, 1988 through October 31, 1991. During this period this DOE-funded work has been focused on several different efforts: (1) experimental studies of the state-to-state dynamics of the H + RH {yields} H{sub 2} R reactions where RH is CH{sub 4}, C{sub 2}H{sub 6}, or C{sub 3}H{sub 8}, (2) theoretical (quasiclassical trajectory) studies of hot hydrogen atom collision dynamics, (3) the development of photochemical sources of translationally hot molecular free radicals and characterization of the high resolution CARS spectroscopy of molecular free radicals, (4) the implementation of stimulated Raman excitation (SRE) techniques for the preparation of vibrationally state-selected molecular reactants.

Valentini, J.J. [Columbia Univ., New York, NY (United States)

1991-12-31

193

Single-collision studies of hot atom energy transfer and chemical reaction  

SciTech Connect

This report discusses research in the collision dynamics of translationally hot atoms, with funding with DOE for the project Single-Collision Studies of Hot Atom Energy Transfer and Chemical Reaction,'' Grant Number DE-FG03-85ER13453. The work reported here was done during the period September 9, 1988 through October 31, 1991. During this period this DOE-funded work has been focused on several different efforts: (1) experimental studies of the state-to-state dynamics of the H + RH {yields} H{sub 2} R reactions where RH is CH{sub 4}, C{sub 2}H{sub 6}, or C{sub 3}H{sub 8}, (2) theoretical (quasiclassical trajectory) studies of hot hydrogen atom collision dynamics, (3) the development of photochemical sources of translationally hot molecular free radicals and characterization of the high resolution CARS spectroscopy of molecular free radicals, (4) the implementation of stimulated Raman excitation (SRE) techniques for the preparation of vibrationally state-selected molecular reactants.

Valentini, J.J. (Columbia Univ., New York, NY (United States))

1991-01-01

194

Transcriptomic signature to oxidative stress exposure at the time of embryonic genome activation in bovine blastocysts.  

PubMed

In order to understand how in vitro culture affects embryonic quality, we analyzed survival and global gene expression in bovine blastocysts after exposure to increased oxidative stress conditions. Two pro-oxidant agents, one that acts extracellularly by promoting reactive oxygen species (ROS) production (0.01 mM 2,2'-azobis (2-amidinopropane) dihydrochloride [AAPH]) or another that acts intracellularly by inhibiting glutathione synthesis (0.4 mM buthionine sulfoximine [BSO]) were added separately to in vitro culture media from Day 3 (8-16-cell stage) onward. Transcriptomic analysis was then performed on resulting Day-7 blastocysts. In the literature, these two pro-oxidant conditions were shown to induce delayed degeneration in a proportion of Day-8 blastocysts. In our experiment, no morphological difference was visible, but AAPH tended to decrease the blastocyst rate while BSO significantly reduced it, indicating a differential impact on the surviving population. At the transcriptomic level, blastocysts that survived either pro-oxidant exposure showed oxidative stress and an inflammatory response (ARRB2), although AAPH induced higher disturbances in cellular homeostasis (SERPINE1). Functional genomics of the BSO profile, however, identified differential expression of genes related to glycine metabolism and energy metabolism (TPI1). These differential features might be indicative of pre-degenerative blastocysts (IGFBP7) in the AAPH population whereas BSO exposure would select the most viable individuals (TKDP1). Together, these results illustrate how oxidative disruption of pre-attachment development is associated with systematic up-regulation of several metabolic markers. Moreover, it indicates that a better capacity to survive anti-oxidant depletion may allow for the survival of blastocysts with a quieter metabolism after compaction. PMID:23426876

Cagnone, Gael L M; Sirard, Marc-André

2013-04-05

195

Mass transfer resistance in a liquid-phase microextraction employing a single hollow fiber under unsteady-state conditions.  

PubMed

In this study, the mass transport resistance in liquid-phase microextraction (LPME) in a single hollow fiber was investigated. A mathematical model has been developed for the determination of the overall mass transfer coefficient based on the acceptor phase in an unsteady state. The overall mass transfer coefficient in LPME in a single hollow fiber has been estimated from time-dependent concentration of extracted analyte in the acceptor phase while maintaining a constant analyte concentration in the donor phase. It can be achieved either using a high volume of donor to acceptor phase ratio or tuning the extraction conditions to obtain a low-enrichment factor, so that the analyte concentration in the sample is not significantly influenced by the mass transfer. Two extraction systems have been used to test experimentally the developed model: the extraction of Lu(III) from a buffer solution and the extraction of three local anesthetics from a buffer or plasma solution. The mass transfer resistance, defined as a reciprocal values of the mass transfer coefficient, was found to be 1.2 × 10(3) cm(-1) min for Lu(III) under optimal conditions and from 1.96 to 3.3 × 10(3) cm(-1) min for the local anesthetics depending on the acceptor pH and the hydrophobicity of the drug. PMID:22997029

Kumri?, Ksenija R; Vladisavljevi?, Goran T; ?or?evi?, Jelena S; Jönsson, Jan Åke; Trti?-Petrovi?, Tatjana M

2012-09-01

196

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

Microsoft Academic Search

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

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

2006-01-01

197

Flux transfer events produced by bursty merging at a single X line  

NASA Astrophysics Data System (ADS)

We present predictions for the signatures of flux transfer events (FTEs) at the dayside magnetopause produced by bursty merging at a single extended X line. In this MHD model, the time-dependent enhanced local resistivity turns on at a low northern latitude for a brief time and then turns off. Realistic ratios of magnetosheath to magnetosphere parameters are chosen to conform with observations and our previous simulations [Ku and Sibeck, 1997, 1998]: ?msh/?sph=10, Bmsh/Bsph=0.5, and Tmsh/Tsph=0.175. The burst of merging produces FTEs marked by strongly asymmetric bipolar magnetic field and plasma velocities normal to the magnetopause in the magnetosheath and no significant signatures in the magnetosphere, just as in the previously studied case for the step-function onset of merging [Ku and Sibeck, 1997]. However, the simulation produces other FTE signatures that differ strikingly from those generated by the step-function onset of merging. After the resistivity is switched off, one or more secondary reconnection sites appear on the trailing edge of the events. Merging at these sites inflates and propels the main FTE as it moves out of the simulation domain. Merging at these sites also fills a magnetic island with hot tenuous plasma near the subsolar (symmetry) point. Transient magnetic islands form on the trailing edge of the main FTE, but these remain small and may disappear. Scatterplots of various parameters versus the plasma density reveal that steep changes for the temperature kT, magnetic field Bz, and the Alfvén velocity occur on the magnetosheath side immediately adjacent to the magnetopause and also reflect the fact that the events scarcely deform the magnetopause.

Ku, Hwar C.; Sibeck, David G.

1998-07-01

198

Feasibility for a Single-Stage-to-Orbit Launch to a Geosynchronous Transfer Orbit by Pulse Laser Propulsion  

NASA Astrophysics Data System (ADS)

An air-breathing pulse laser powered launcher has been proposed as an alternative to conventional chemical launch systems. The trajectory from the ground to a geosynchronous transfer orbit by pulse laser propulsion is calculated by modeling the thrust during pulsejet, ramjet and rocket flight modes, and the launch cost is estimated. The results show that the pulse laser powered launcher can transfer 0.085kg payload per 1MW beam power to a geosynchronous orbit, and the cost becomes quarter of existing systems if one can divide a single launch into 22,500 multiple launches.

Katsurayama, Hiroshi; Komurasaki, Kimiya; Arakawa, Yoshihiro

199

Single-molecule fluorescence spectroscopy studies of photo-induced electron transfer between CdSe\\/ZnS quantum dots and fullerene  

Microsoft Academic Search

Photo-induced electron transfer in CdSe\\/ZnS semiconductor quantum dot-fullerene conjugates was investigated by single molecule fluorescence spectroscopy. The average rate for photoinduced electron transfer is estimated around 108s-1. Quenching by electron transfer is observed in the \\

Zhihua Xu; Mircea Cotlet

2010-01-01

200

Atypical protein kinase C couples cell sorting with primitive endoderm maturation in the mouse blastocyst.  

PubMed

During mouse pre-implantation development, extra-embryonic primitive endoderm (PrE) and pluripotent epiblast precursors are specified in the inner cell mass (ICM) of the early blastocyst in a 'salt and pepper' manner, and are subsequently sorted into two distinct layers. Positional cues provided by the blastocyst cavity are thought to be instrumental for cell sorting; however, the sequence of events and the mechanisms that control this segregation remain unknown. Here, we show that atypical protein kinase C (aPKC), a protein associated with apicobasal polarity, is specifically enriched in PrE precursors in the ICM prior to cell sorting and prior to overt signs of cell polarisation. aPKC adopts a polarised localisation in PrE cells only after they reach the blastocyst cavity and form a mature epithelium, in a process that is dependent on FGF signalling. To assess the role of aPKC in PrE formation, we interfered with its activity using either chemical inhibition or RNAi knockdown. We show that inhibition of aPKC from the mid blastocyst stage not only prevents sorting of PrE precursors into a polarised monolayer but concomitantly affects the maturation of PrE precursors. Our results suggest that the processes of PrE and epiblast segregation, and cell fate progression are interdependent, and place aPKC as a central player in the segregation of epiblast and PrE progenitors in the mouse blastocyst. PMID:24067354

Saiz, Néstor; Grabarek, Joanna B; Sabherwal, Nitin; Papalopulu, Nancy; Plusa, Berenika

2013-09-25

201

High-frequency phage-mediated gene transfer in freshwater environments determined at single-cell level.  

PubMed

Lateral gene transfer by phages has contributed significantly to the genetic diversity of bacteria. To accurately determine the frequency and range of phage-mediated gene transfer, it is important to understand the movement of DNA among microbes. Using an in situ DNA amplification technique (cycling primed in situ amplification-fluorescent in situ hybridization; CPRINS-FISH), we examined the propensity for phage-mediated gene transfer in freshwater environments at the single-cell level. Phage P1, T4 and isolated Escherichia coli phage EC10 were used as vectors. All E. coli phages mediated gene transfer from E. coli to both plaque-forming and non-plaque-forming Enterobacteriaceae strains at frequencies of 0.3-8 x 10(-3) per plaque-forming unit (PFU), whereas culture methods using selective agar media could not detect transductants in non-plaque-forming strains. The DNA transfer frequencies through phage EC10 ranged from undetectable to 9 x 10(-2) per PFU (undetectable to 2 x 10(-3) per total direct count) when natural bacterial communities were recipients. Direct viable counting combined with CPRINS-FISH revealed that more than 20% of the cells carrying the transferred gene retained their viability in most cases. These results indicate that the exchange of DNA sequences among bacteria occurs frequently and in a wide range of bacteria, and may promote rapid evolution of the prokaryotic genome in freshwater environments. PMID:20090786

Kenzaka, Takehiko; Tani, Katsuji; Nasu, Masao

2010-01-21

202

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

2013-07-30

203

Direct electrical single-molecule detection of DNA through electron transfer induced by hybridization.  

PubMed

Single-stranded DNA was utilized as a probe tip for single-molecule DNA detection. Hybridization of the DNA tip and target DNA induces electron tunneling through the resulting DNA duplex. It is demonstrated that the DNA tip allows not only genetic detection but also discovery of single-nucleotide polymorphisms at the single-molecule level. PMID:23508214

Nishino, Tomoaki; Bui, Phuc Tan

2013-04-28

204

Multiorgan engraftment of human somatic cells in swine foetuses after intra-blastocyst transplantation.  

PubMed

Adult human stem cells, mainly from hematopoietic lineage, have been injected into developing pre-immune animal foetuses, and xenogenic engraftment of liver and other organs has been reported. We isolated a rare cell population from adult human liver, fat and skin. Colonies with few cells became visible as early as 2-3 days, and a fully formed colony took 10-14 days to form. These colonies were named as liver-derived cell lines (LDCs), fat-derived cell lines (FDCs) and skin-derived cell lines (SDCs). All these cells express few pluripotency markers like Klf4, c-myc and Sox2. Pig blastocysts were injected with LDCs, FDCs and SDCs and transferred to recipient pigs. We achieved an overall pregnancy rate of 71.4% at day 35. The foetuses were analysed for human cell chimerism in liver, kidney and heart both by RT-PCR and real-time PCR using primers specific to human and pig mitochondrial DNA. The percentage of foetuses showing chimerism was 17.4% (4/23), 12.5% (2/16) and 11.1% (1/9) for LDCs, FDCs and SDCs, respectively. Of these, 42.9% (three out of seven) showed chimerism in liver and 71.4% (five out of seven) showed kidney chimerism. However, we did not detect any chimerism in the heart. The level of chimerism varied and was in the range of one human cell per one hundred thousand to one million pig cells. PMID:21092066

Estrada, J; Li, P; Mir, B

2010-11-23

205

DNA methylation status of bovine blastocyst embryos obtained from various procedures.  

PubMed

DNA methylation is an important factor for the regulation of gene expression in early embryos. It is well known that the satellite I sequence is more heavily methylated in bovine somatic cell nuclear transfer (NT-SC) embryos than in embryos derived from in vitro fertilization (IVF). However, the methylation status of bovine embryos obtained by other procedures is not well known. To clarify DNA methylation levels of bovine embryos obtained from various procedures, we examined satellite I sequences in bovine blastocyst (BC) embryos derived from NT-SC, NT using embryonic blastomeres (NT-EM), in vivo (Vivo), IVF and parthenogenetic treatment (PA). Furthermore, in order to evaluate the efficacy of DNA demethylation by the NT procedure, we determined the DNA methylation levels in bovine embryos in which NT was recapitulated (Re-NT). Although the DNA methylation levels in the NT-SC embryos were higher than those in the other embryos, the NT-EM embryos exhibited lower DNA methylation levels. The satellite I sequence in the NT-SC embryos was more demethylated than that in the donor cells. Although the DNA methylation level in the individual NT-SC embryos showed variation, the full-term developmental efficacy of these embryos were not different. These findings suggest that the methylation level of the satellite I sequence at the BC stage is not related to the abnormalities of bovine embryos produced by NT-SC. There was no difference in methylation levels between Re-NT and NT-SC embryos. Our results indicated that the DNA methylation status differed among embryos produced by various methods and that at least some of the demethylation of the donor cell genome occurred in the recipient cytoplast after NT-SC, but the demethylation ability of the NT procedure was noted in the first NT but not in the second NT. PMID:21139327

Sawai, Ken; Takahashi, Masashi; Fujii, Takashi; Moriyasu, Satoru; Hirayama, Hiroki; Minamihashi, Akira; Hashizume, Tsutomu; Onoe, Sadao

2010-12-03

206

Local field effects in the energy transfer between a chromophore and a carbon nanotube: a single-nanocompound investigation.  

PubMed

Energy transfer in noncovalently bound porphyrin/carbon nanotube compounds is investigated at the single-nanocompound scale. Excitation spectroscopy of the luminescence of the nanotube shows two resonances arising from intrinsic excitation of the nanotube and from energy transfer from the porphyrin. Polarization diagrams show that both resonances are highly anisotropic, with a preferred direction along the tube axis. The energy transfer is thus strongly anisotropic despite the almost isotropic absorption of porphyrins. We account for this result by local field effects induced by the large optical polarizability of nanotubes. We show that the local field correction extends over several nanometers outside the nanotubes and drives the overall optical response of functionalized nanotubes. PMID:23005601

Roquelet, Cyrielle; Vialla, Fabien; Diederichs, Carole; Roussignol, Philippe; Delalande, Claude; Deleporte, Emmanuelle; Lauret, Jean-Sébastien; Voisin, Christophe

2012-09-24

207

Single-molecule fluorescence spectroscopy studies of photo-induced electron transfer between CdSe/ZnS quantum dots and fullerene  

NASA Astrophysics Data System (ADS)

Photo-induced electron transfer in CdSe/ZnS semiconductor quantum dot-fullerene conjugates was investigated by single molecule fluorescence spectroscopy. The average rate for photoinduced electron transfer is estimated around 108s-1. Quenching by electron transfer is observed in the "on" state and it manifests both as reduced fluorescence intensity and as shortening in fluorescence lifetime. As a result, the electron transfer changes the on/off dynamics of the fluorescence intensity of individual quantum dots.

Xu, Zhihua; Cotlet, Mircea

2010-02-01

208

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.

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

209

GLUT8 is a glucose transporter responsible for insulin-stimulated glucose uptake in the blastocyst  

PubMed Central

Mammalian preimplantation blastocysts exhibit insulin-stimulated glucose uptake despite the absence of the only known insulin-regulated transporter, GLUT4. We describe a previously unidentified member of the mammalian facilitative GLUT superfamily that exhibits ?20–25% identity with other murine facilitative GLUTs. Insulin induces a change in the intracellular localization of this protein, which translates into increased glucose uptake into the blastocyst, a process that is inhibited by antisense oligoprobes. Presence of this transporter may be necessary for successful blastocyst development, fuel metabolism, and subsequent implantation. Moreover, the existence of an alternative transporter may explain examples in other tissues of insulin-regulated glucose transport in the absence of GLUT4.

Carayannopoulos, Mary O.; Chi, Maggie M.-Y.; Cui, Ying; Pingsterhaus, Joyce M.; McKnight, Robert A.; Mueckler, Mike; Devaskar, Sherin U.; Moley, Kelle H.

2000-01-01

210

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

211

Technological experiments and mathematical modeling of the fluid dynamics and heat transfer in gallium arsenide single-crystal growth processes  

Microsoft Academic Search

Mathematical modeling is combined with technological experiments to study the flow and heat transfer processes of gallium\\u000a arsenide (GaAs) single-crystal growth by the Czochralski method. When the heat wave produced by periodic variation of the\\u000a heatertemperature acts upon the molten material regions adjacent to the crystallization front. It is shown that such comparatively\\u000a low-energy excitation makes it possible to reduce

V. G. Zakharov; V. G. Kosushkin; S. A. Nikitin; V. I. Polezhaev

1998-01-01

212

Studies on the structure and dynamics of the human telomeric G quadruplex by single-molecule fluorescence resonance energy transfer  

Microsoft Academic Search

We have investigated the structure and unfolding kinetics of the human telomeric intramolecular G quadruplex by using single-molecule fluorescence resonance energy transfer. An exploration of conformational heterogeneity revealed two stable folded conformations, in both sodium- and potassium-containing buffers, with small differences between their enthalpies and entropies. Both folded conformations can be opened by the addition of a 21-base complementary DNA

Liming Ying; Jeremy J. Green; Haitao Li; David Klenerman; Shankar Balasubramanian

2003-01-01

213

Direct observation of resonant energy transfer between quantum dots of two different sizes in a single water droplet  

Microsoft Academic Search

Water soluble CdTe nanocrystals (NCs) of two different sizes capped by thioglycolic acid were synthesized and were dispersed in pure water. We have observed that the emission color of CdTe NCs has been changed in a single droplet of water during the evaporation of the solvent. This is attributed to Förster resonance energy transfer between CdTe NCs, when their concentration

Ling Xu; Jun Xu; Zhongyuan Ma; Wei Li; Xinfan Huang; Kunji Chen

2006-01-01

214

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

Microsoft Academic Search

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

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

2011-01-01

215

Intramolecular Distances and Dynamics from the Combined Photon Statistics of Single-Molecule FRET and Photoinduced Electron Transfer.  

PubMed

Single-molecule Förster resonance energy transfer (FRET) and photoinduced electron transfer (PET) have developed into versatile and complementary methods for probing distances and dynamics in biomolecules. Here we show that the two methods can be combined in one molecule to obtain both accurate distance information and the kinetics of intramolecular contact formation. In a first step, we show that the fluorescent dyes Alexa 488 and Alexa 594, which are frequently used as a donor and acceptor for single-molecule FRET, are also suitable as PET probes with tryptophan as a fluorescence quencher. We then performed combined FRET/PET experiments with FRET donor- and acceptor-labeled polyproline peptides. The placement of a tryptophan residue into the polyglycylserine tail incorporated in the peptides allowed us to measure both FRET efficiencies and the nanosecond dynamics of contact formation between one of the fluorescent dyes and the quencher. Variation of the linker length between the polyproline and the Alexa dyes and in the position of the tryptophan residue demonstrates the sensitivity of this approach. Modeling of the combined photon statistics underlying the combined FRET and PET process enables the accurate analysis of both the resulting transfer efficiency histograms and the nanosecond fluorescence correlation functions. This approach opens up new possibilities for investigating single biomolecules with high spatial and temporal resolution. PMID:23718771

Haenni, Dominik; Zosel, Franziska; Reymond, Luc; Nettels, Daniel; Schuler, Benjamin

2013-05-29

216

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

217

Influence of group culture and culture volume on the formation of human blastocysts: a prospective randomized study  

Microsoft Academic Search

The optimal culture conditions for embryos to reach the blastocyst stage are under investigation. One factor is the putative influence of autocrine or paracrine factors produced by the embryo itself. Studies in mice blastocysts showed a beneficial influence of micro-cultures and com- munal growth on pregnancy and implantation rates, attrib- uted to these growth or survival factors. In humans, studies

P. M. Rijnders; C. A. M. Jansen

1999-01-01

218

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer  

NASA Astrophysics Data System (ADS)

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single-component two-phase thermal control systems for various gravity environments.

Delil, A. A. M.

2003-01-01

219

IGF-1\\/IGFBP-1 increases blastocyst formation and total blastocyst cell number in mouse embryo culture and facilitates the establishment of a stem-cell line  

Microsoft Academic Search

BACKGROUND: Apoptosis occurs frequently for blastocysts cultured in vitro, where conditions are suboptimal to those found in the natural environment. Insulin-like growth factor-1 (IGF-1) plays an important role in preventing apoptosis in the early development of the embryo, as well as in the progressive regulation of organ development. We hypothesize that IGF-1 and its dephosphorylated binding protein (IGFBP-1) may be

Ta-Chin Lin; Jui-Mei Yen; Kun-Bing Gong; Teng-Tsao Hsu; Lih-Ren Chen

2003-01-01

220

Blastocysts don't go it alone. Extrinsic signals fine-tune the intrinsic developmental program of trophoblast cells  

PubMed Central

The preimplantation embryo floats freely within the oviduct and is capable of developing into a blastocyst independently of the maternal reproductive tract. While establishment of the trophoblast lineage is dependent on expression of developmental regulatory genes, further differentiation leading to blastocyst implantation in the uterus requires external cues emanating from the microenvironment. Recent studies suggest that trophoblast differentiation requires intracellular signaling initiated by uterine-derived growth factors and integrin-binding components of the extracellular matrix. The progression of trophoblast development from the early blastocyst stage through the onset of implantation appears to be largely independent of new gene expression. Instead, extrinsic signals direct the sequential trafficking of cell surface receptors to orchestrate the developmental program that initiates blastocyst implantation. The dependence on external cues could coordinate embryonic activities with the developing uterine endometrium. Biochemical events that regulate trophoblast adhesion to fibronectin are presented to illustrate a developmental strategy employed by the peri-implantation blastocyst.

Armant, D. Randall

2009-01-01

221

Single- and two-phase convective heat transfer from smooth and enhanced microelectronic heat sources in a rectangular channel  

SciTech Connect

Experiments have been performed to assess the feasibility of cooling microelectronic components by means of single-phase and two-phase forced convection. Tests were conducted using a single heat source flush mounted to one wall of a vertical rectangular channel. An inert fluorocarbon liquid (FC-72) was circulated upward through the channel at velocities up to 4.1 m/s and with subcooling up to 46 {degree}C. The simulated microelectronic heat sources tested in this study include a smooth surface and three low-profile microstud surfaces of varying stud height, each having a base area of 12.7{times}12.7 mm{sup 2}. Correlations were developed for the single-phase convective heat transfer coefficient over the Reynolds number range from 2800 to 1.5{times}10{sup 5}, where Reynolds number is based on the length of the heater. The results demonstrate that the low thermal resistances required for cooling of microelectronic heat sources may be achieved with single-phase forced convection by using high fluid velocity coupled with surface enhancement. Experiments were also performed to understand better the parametric trends of boiling heat transfer from the simulated microelectronic heat source. It was found that increased velocity and subcooling and the use of microstud surfaces enhance nucleate boiling, increase the critical heat flux, and reduce the magnitude of temperature overshoot upon the inception of nucleation.

Maddox, D.E.; Mudawar, I. (Boiling and Two-Phase Flow Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (US))

1989-11-01

222

IGF-1/IGFBP-1 increases blastocyst formation and total blastocyst cell number in mouse embryo culture and facilitates the establishment of a stem-cell line  

PubMed Central

Background Apoptosis occurs frequently for blastocysts cultured in vitro, where conditions are suboptimal to those found in the natural environment. Insulin-like growth factor-1 (IGF-1) plays an important role in preventing apoptosis in the early development of the embryo, as well as in the progressive regulation of organ development. We hypothesize that IGF-1 and its dephosphorylated binding protein (IGFBP-1) may be able to improve embryo culture with an associated reduced cell death, and that the resultant increase in the total cell number of the embryo could increase the chances of establishing an embryonic stem-cell line. Results In vivo fertilized zygotes were cultured in medium containing supplementary IGF-1, or IGFBP-1/IGF-1. The stages of the resultant embryos were evaluated at noon on day five post-hCG injection. The extent of apoptosis and necrosis was evaluated using Annexin V and propidium iodine staining under fluorescent microscopy. The establishment of embryonic stem-cell lines was performed using the hatching blastocysts that were cultured in the presence of IGF-1 or IGFBP-1/IGF-1. The results show that the rate of blastocyst formation in a tissue-culture system in the presence of IGF-1 was 88.7% and IGFBP-1/IGF-1 it was 94.6%, respectively, and that it was significantly greater than the figure for the control group (81.9%). IGFBP-1/IGF-1 also resulted in a higher hatching rate than was the case for the control group (68.8% vs. 48.6% respectively). IGF-1 also increased the number of Annexin V-free and propidium iodine-free blastocysts in culture (86.8% vs. 75.9% respectively). Total cell number of blastocyst in culture was increased by 18.9% for those examples cultured with dephosphorylated IGFBP-1/IGF-1. For subsequent stem-cell culture, the chances of the successful establishment of a stem-cell line was increased for the IGF-1 and IGFBP-1/IGF-1 groups (IGF-1 vs. IGFBP-1/IGF-1 vs. control: 45.8% vs. 59.6% vs. 27.3% respectively). Conclusion IGF-1 or dephosphorylated IGFBP-1/IGF-1 supplement does result in an anti-apoptotic effect for early embryo development in culture, with a subsequent increased total cell number resulting from cell culture. The effect is beneficial for the later establishment of a stem-cell line.

Lin, Ta-Chin; Yen, Jui-Mei; Gong, Kun-Bing; Hsu, Teng-Tsao; Chen, Lih-Ren

2003-01-01

223

Coupled radiative and conductive heat transfer across honeycomb panels and through single cells  

NASA Astrophysics Data System (ADS)

In the absence of natural convection, heat flows through a gas-filled honeycomb by conduction and radiation. For the parameter ranges of interest in a plastic honeycomb inside a flat plate solar collector, the conduction and radiation are strongly coupled. The total heat transfer across the panel was studied experimentally and theoretically. The experimental approach precisely measured the total heat transfer under varying conditions. The theoretical approach proposed several models, established their governing equations, and solved the equations by either numerical or analytical methods. A model based on grey surfaces, specular sidewalls, and one-dimensional conduction yielded results within 6 percent of measurements.

Hollands, K. G. T.; Raithby, G. D.; Russell, F. B.; Wilkinson, R. G.

1984-11-01

224

Origin and Fate of the 3? Ends of Single-Stranded DNA Generated by Conjugal Transfer of Plasmid R1162  

PubMed Central

During conjugation, a single strand of DNA is cleaved at the origin of transfer (oriT) by the plasmid-encoded relaxase. This strand is then unwound from its complement and transferred in the 5?-to-3? direction, with the 3? end likely extended by rolling-circle replication. The resulting, newly synthesized oriT must then be cleaved as well, prior to recircularization of the strand in the recipient. Evidence is presented here that the R1162 relaxase contains only a single nucleophile capable of cleaving at oriT, with another molecule therefore required to cleave at a second site. An assay functionally isolating this second cleavage shows that this reaction can take place in the donor cell. As a result, there is a flux of strands with free 3? ends into the recipient. These ends are susceptible to degradation by exonuclease I. The degree of susceptibility is affected by the presence of an uncleaved oriT within the strand. A model is presented where these internal oriTs bind and trap the relaxase molecule covalently bound to the 5? end of the incoming strand. Such a mechanism would result in the preferential degradation of transferred DNA that had not been properly cleaved in the donor.

Becker, Eric C.

2012-01-01

225

Interfacial charge transfer mechanism in nanostructured TiO2-ZnS coupled network for single electron device applications  

NASA Astrophysics Data System (ADS)

We report on the production of nanoporous TiO2 network sensitized by ZnS nanospheres as an idealized scheme to facilitate interfacial charge transfer effects. The nanoporous TiO2 system was fabricated on the 0.1 ?m thick Al substrate from titanium isopropoxide [Ti(i-OC3H7)] and 1-butanol (C4H9OH) as requisite precursor. The Zn++ ions are internally adsorbed to provide heterogeneous coupled TiO2-ZnS nanosystem. The I-V response shows transistor characteristics which suggests sharp rise in current with forward biasing voltage before attaining saturation. It is expected that with the increase in signal frequency more number of trap carriers being able to follow signal assist higher carrier transfer rate across the interface in the coupled system and hence saturation current (IS) increases. However, in all the cases saturation occurs around finite biasing voltage, i.e., 3.6 V. This ensures that the surface states (which normally lie within the forbidden gap and below the conduction bands for electrons) mainly participate in carrier transfer mechanism within the device. A phenomenon in understanding highly controlled interfacial carrier transport process would find potential in nanoelectronics, e.g., single electron transistor and other single electron devices.

Mohanta, D.; Deka, M.; Choudhury, A.

2007-02-01

226

FGF4-dependent stem cells derived from rat blastocysts differentiate along the trophoblast lineage.  

PubMed

Differentiated trophoblast cell lineages arise from trophoblast stem (TS) cells. To date such a stem cell population has only been established in the mouse. The objective of this investigation was to establish TS cell populations from rat blastocysts. Blastocysts were cultured individually on a feeder layer of rat embryonic fibroblasts (REFs) in fibroblast growth factor-4 (FGF4) and heparin supplemented culture medium. Once cell colonies were established REF feeder layers could be replaced with REF conditioned medium. The blastocyst-derived cell lines, in either proliferative or differentiated states, did not express genes indicative of ICM-derived tissues. In the proliferative state the cells expressed established stem cell-associated markers of TS cells. Cells ceased proliferation and differentiated when FGF4, heparin, and REF conditioned medium were removed. Differentiation was characterized by a decline of stem cell-associated marker gene expression, the appearance of large polyploid cells (trophoblast giant cells), and the expression of trophoblast differentiation-associated genes. Collectively, the data indicate that the rat blastocyst-derived cell lines not only possess many features characteristic of mouse TS cells but also possess some distinct properties. These rat TS cell lines represent valuable new in vitro models for analyses of mechanisms controlling TS cell renewal and differentiation. PMID:21215265

Asanoma, Kazuo; Rumi, M A Karim; Kent, Lindsey N; Chakraborty, Damayanti; Renaud, Stephen J; Wake, Norio; Lee, Dong-Soo; Kubota, Kaiyu; Soares, Michael J

2011-01-05

227

Growth hormone, insulin-like growth factor I and cell proliferation in the mouse blastocyst  

Microsoft Academic Search

at higher and lower concentrations. GH increased the number of cells in the trophectoderm by 25%, but did not affect the inner cell mass of blastocysts. Inhibition of cell proliferation by anti-GH antiserum indicated that GH is a potent autocrine or paracrine regulator of the number of trophectoderm cells in vivo .T ype 1 IGF receptors (IGF1R) were localized to

K. E. Markham; P. L. Kaye

2003-01-01

228

Cryopreserved Morulae can be used to Efficiently Generate Germline-transmitting Chimeras by Blastocyst Injection  

Microsoft Academic Search

The production of chimeric mice is a complex process, requiring the careful coordination of tissue culture cell growth, production of a large number (30–75) of competent blastocysts and the availability of appropriately timed pseudo pregnant female mice. Failure at any of these steps can impinge upon the rapid production of chimeras. One potential improvement for the efficient generation of chimeric

Janice V. Parker-Thornburg; Jennifer L. Alana; Chad N. Smith; Michelle Detry; Marta L. Rojas; Kedryn K. Baskin

2005-01-01

229

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

230

ES cells derived from cloned and fertilized blastocysts are transcriptionally and functionally indistinguishable  

PubMed Central

Reproductive cloning is uniformly rejected as a valid technology in humans because of the severely abnormal phenotypes seen in cloned animals. Gene expression aberrations observed in tissues of cloned animals have also raised concerns regarding the therapeutic application of “customized” embryonic stem (ES) cells derived by nuclear transplantation (NT) from a patient's somatic cells. Although previous experiments in mice have demonstrated that the developmental potential of ES cells derived from cloned blastocysts (NT-ES cells) is identical to that of ES cells derived from fertilized blastocysts, a systematic molecular characterization of NT-ES cell lines is lacking. To investigate whether transcriptional aberrations, similar to those observed in tissues of cloned mice, also occur in NT-ES cells, we have compared transcriptional profiles of 10 mouse NT- and fertilization-derived-ES cell lines. We report here that the ES cell lines derived from cloned and fertilized mouse blastocysts are indistinguishable based on their transcriptional profiles, consistent with their normal developmental potential. Our results indicate that, in contrast to embryonic and fetal development of clones, the process of NT-ES cell derivation rigorously selects for those immortal cells that have erased the “epigenetic memory” of the donor nucleus and, thus, become functionally equivalent. Our findings support the notion that ES cell lines derived from cloned or fertilized blastocysts have an identical therapeutic potential.

Brambrink, Tobias; Hochedlinger, Konrad; Bell, George; Jaenisch, Rudolf

2006-01-01

231

Global gene expression of the inner cell mass and trophectoderm of the bovine blastocyst  

PubMed Central

Background The first distinct differentiation event in mammals occurs at the blastocyst stage when totipotent blastomeres differentiate into either pluripotent inner cell mass (ICM) or multipotent trophectoderm (TE). Here we determined, for the first time, global gene expression patterns in the ICM and TE isolated from bovine blastocysts. The ICM and TE were isolated from blastocysts harvested at day 8 after insemination by magnetic activated cell sorting, and cDNA sequenced using the SOLiD 4.0 system. Results A total of 870 genes were differentially expressed between ICM and TE. Several genes characteristic of ICM (for example, NANOG, SOX2, and STAT3) and TE (ELF5, GATA3, and KRT18) in mouse and human showed similar patterns in bovine. Other genes, however, showed differences in expression between ICM and TE that deviates from the expected based on mouse and human. Conclusion Analysis of gene expression indicated that differentiation of blastomeres of the morula-stage embryo into the ICM and TE of the blastocyst is accompanied by differences between the two cell lineages in expression of genes controlling metabolic processes, endocytosis, hatching from the zona pellucida, paracrine and endocrine signaling with the mother, and genes supporting the changes in cellular architecture, stemness, and hematopoiesis necessary for development of the trophoblast.

2012-01-01

232

Susceptibility of in vitro produced hatched bovine blastocysts to infection with bluetongue virus serotype 8  

PubMed Central

Bluetongue virus serotype 8 (BTV-8), which caused an epidemic in ruminants in central Western Europe in 2006 and 2007, seems to differ from other bluetongue serotypes in that it can spread transplacentally and has been associated with an increased incidence of abortion and other reproductive problems. For these reasons, and also because BTV-8 is threatening to spread to other parts of the world, there is a need for more information on the consequences of infection during pregnancy. The aim of the present study was to investigate whether hatched (i.e. zona pellucida-free) in vitro produced bovine blastocysts at 8-9 days post insemination are susceptible to BTV-8 and whether such infection induces cell death as indicated by apoptosis. Exposure of hatched in vitro produced bovine blastocysts for 1 h to a medium containing 103.8 or 104.9 TCID50 of the virus resulted in active viral replication in between 25 and 100% of the cells at 72 h post exposure. The infected blastocysts also showed growth arrest as evidenced by lower total cell numbers and a significant level of cellular apoptosis. We conclude from this in vitro study that some of the reproductive problems that are reported when cattle herds are infected with BTV-8 may be attributed to direct infection of blastocysts and other early-stage embryos in utero.

2011-01-01

233

High-fin staggered tube banks: Heat transfer and pressure drop for turbulent single phase gas flow  

NASA Astrophysics Data System (ADS)

This Data Item ESDU 86022 is an addition to the Heat Transfer Sub-series. New correlations are presented for external heat transfer coefficient and static pressure loss for single phase flow over plain circular fins of either retangular or tapered cross section on round tubes. The correlations were derived by a regression analysis of experimental results extracted from the literature for a wide range of tube bundle configurations. Fin densities of 4 to 11 per inch (equivalent to fin pitches of 6.4 to 2.3 mm) tube outside diameters of 3/8 to 2 inch (10 to 51 mm), fin heights of 1/4 to 5/8 inch (6 to 16 mm), and ratios of fin tip to fin root diameter of 1.2 to 2.4 were covered. For heat transfer the range of Reynolds number based on tube outer diameter was from 2,000 to 40,000 and for pressure drop from 5,000 to 50,000. Comparison of the prediction with experiment shows that for heat transfer 85% of the data points were within 10% of estimated and for pressure drop 72% were within 10%. A comprehensive worked example showing the use of the method for an air cooled heat exchanger bundle is included. The applicability of this method to nonintegral fins is considered and factors influencing the thermal resistance of the interface are discussed. Effects of fouling are also briefly covered.

1986-10-01

234

Efficient population transfer in modulation doped single quantum wells by intense few-cycle terahertz pulses  

NASA Astrophysics Data System (ADS)

We demonstrate the direct observation of non-equilibrium intersubband dynamics in a modulation-doped multiple quantum well sample subject to intense few-cycle terahertz (THz) pulses. The transmission spectra show a distinct dependence on the incident THz field strength and contain signatures of a multitude of nonlinear effects that can be observed owing to the large THz-pulse bandwidth. We focus our attention on a case of transient nonlinear refractive index caused by the efficient transfer of electronic population from the ground state to higher-excited states of the quantum well sample. By comparing the experimental results with a one-dimensional finite-difference model going beyond the slowly varying envelope approximation, we prove that, depending on the pulse shape, the leading part of the intense pulse efficiently transfers electrons from the ground state to higher lying excited states. For weak electric fields and small-population transfer, the linear Lorentz model holds. For strong electric fields, up to 55 and 20% of the ground-state electrons are transferred to the first and second excited subbands, respectively, which could lead to the observation of the optical gain.

Dietze, Daniel; Darmo, Juraj; Unterrainer, Karl

2013-06-01

235

A Single Model for Mass Transfer and Growth for Biodegradation Rates in Activated Sludge  

Microsoft Academic Search

In the scope of environmental risk assessment for new and existing chemicals a generic model is developed to predict the possible concentration of pollutants after passage of sewage treatment plants. The model combines Monod kinetics with mass transfer rates through an imaginary boundary layer between mixed liquor and active biomass. For each specific substance a combined rate constant can be

J. Blok

2001-01-01

236

Energy minimization of single input orbit transfer by averaging and continuation  

Microsoft Academic Search

This article deals with the transfer between Keplerian coplanar orbits using low propulsion. We focus on the energy minimization problem and compute the averaged system, proving integrability and relating the corresponding trajectories to a three-dimensional Riemannian problem that is analyzed in details. The geodesics provide approximations of the extremals of the energy minimization problem and can be used in order

Bernard Bonnard; Jean-Baptiste Caillau; Romain Dujol

2006-01-01

237

Proton transfer at the carboxylic sites of amino acids: A single water molecule catalyzed process  

NASA Astrophysics Data System (ADS)

Ab initio calculations at MP2 level of theory were used to study the proton transfer at the carboxylic sites of amino acids, in the isolated, mono- and di-hydrated forms. In the case of water dimer, two interaction modes with glycine neutral structures (see Fig. ) were explored, corresponding to the concerted and stepwise reaction pathways. Their transition states can be described as (H2O bond H bond OH2)+ [Fig. (a)] and (H2O---H bond OH2)+ [Fig. (b)], respectively. The energy analysis indicated that the concerted pathway is preferred. In the isolated, mono- and di-hydrated glycine complexes, the activation barriers of the proton transfer at the carboxylic sites were calculated to be 34.49, 16.59, and 13.36 kcal mol-1, respectively. It was thus shown that the proton transfer is significantly assisted and catalyzed by water monomer so that it can take place at room temperature. Instead, the further addition of water molecules plays solvent effects rather than catalytic effects to this proton transfer process. The above results obtained with discrete water molecules were supported by the solvent continuum calculated data. It was also observed that the heavy dependence of the solvent continuum models on dipole moments may produce misleading results.

Yang, Gang; Wu, Xiaomin; Zu, Yuangang; Liu, Chengbu; Fu, Yujie; Zhou, Lijun

238

Single-phase heat transfer in the high temperature multiple porous insulation  

Microsoft Academic Search

An experimental study of steady state flow and heat transfer has been conducted for the multiple plate porous insulation used in the reactor pressure vessels of ‘Magnox’ nuclear power stations. The insulation pack studied, consisting of seven dimpled stainless steel sheets and six plane stainless steel sheets, was of the type installed in the Sizewell A plant. A large scale

T. K. Lim; B. P. Axcell; M. A. Cotton

2007-01-01

239

Multiparameter single molecule spectroscopy gives insight into the complex photophysics of fluorescence energy transfer (FRET) coupled biosystems  

NASA Astrophysics Data System (ADS)

Since the discovery of the technique in the early 1990s, single molecule spectroscopy has been used as a powerful tool to investigate and characterize fluorescent molecules, revealing insights into molecular behavior far beyond the information content that can be obtained by conventional ensemble studies. Several spectroscopic techniques have been established at the single molecule level, including spectrally resolved fluorescence, fluorescence lifetime investigations, or single molecule Raman measurements. However, the combination of two or more of these spectroscopies applied to the same individual molecule in multiparameter approaches yields a deeper understanding of molecular systems. In this contribution, we present our results of combined spectrally- and time-resolved fluorescence microscopy of the intrinsic fluorescence energy transfer (FRET) system of the red fluorescent protein DsRed. Correlating the results obtained from the two spectroscopic techniques, we are able to determine all relevant parameters to describe the energy transfer processes within the DsRed system without any further assumptions. We further discuss fluorescence and surface enhanced Raman scattering (SERS) spectroscopy of the same individual DsRed unit, which can help to propose mechanisms for photodegeneration of the distinct chromophores involved.

Schleifenbaum, F.; Blum, C.; Elgass, K.; Peter, S.; Subramaniam, V.; Meixner, A. J.

2009-02-01

240

Epigenetic differences between male and female bovine blastocysts produced in vitro.  

PubMed

Epigenetic differences between male and female bovine blastocysts provide a plausible link between physiological and gene transcription differences observed between male and female embryos. The aim of this study was to examine sex-related epigenetic differences in bovine blastocysts produced in vitro. Oocytes were matured in vitro and inseminated with frozen-thawed sex-sorted (X or Y) and unsorted (control) bull sperm. Zygotes were cultured to blastocyst stage and were analyzed for embryo sexing, mtDNA content, telomere lengths, methylation analysis, and quantification of mRNA transcripts of DNA methyltransferases (Dnmt1, Dnmt3a, Dnmt3b) HMT1 hnRNP methyltransferase-like 2 (Hmt1), and interleukin enhancer binding factor 3 (Ilf3). There was a difference (P < 0.05) in the mean mtDNA copy number between male (410,000 +/- 23,000) and female (360,000 +/- 21,000) blastocysts. Telomere length was shorter in male blastocysts (P < 0.01). The level of methylation in a sequence near a variable number of tandem repeats minisatellite region [variable number of tandem repeats (VNTR)] in males (39.8% +/- 4.8) was higher than in females (23.7% +/- 3.1) (P < 0.05); however, no differences were found in other regions analyzed. Moreover, transcription differences between sexes were observed for Dnmt3a, Dnmt3b, Hmt1, and Ilf3. These results provide evidence of epigenetic differences between male and female bovine in vitro produced embryos and suggest that before initiation of gonadal differentiation, epigenetic events may modulate the difference between speed of development, metabolism, and transcription observed during preimplantation development between male and female embryos. PMID:17986520

Bermejo-Alvarez, P; Rizos, D; Rath, D; Lonergan, P; Gutierrez-Adan, A

2007-11-06

241

Importance of methionine metabolism in morula-to-blastocyst transition in bovine preimplantation embryos.  

PubMed

The roles of methionine metabolism in bovine preimplantation embryo development were investigated by using ethionine, an antimetabolite of methionine. In vitro produced bovine embryos that had developed to the 5-cell stage or more at 72 h after the commencement of in vitro fertilization (IVF) were then cultured until day 8 (IVF = day 0) in medium supplemented with 0 (control), 1, 5 and 10 mM ethionine. Compared with the blastocyst development in the control (40.0%), ethionine at 10 mM almost completely blocked blastocyst development (1.1%, P<0.001), and this concentration was used in the following experiments. Methionine added at the same concentration (10 mM, a concentration control of ethionine) did not cause such an intense developmental inhibition. Development to the compacted morula stage on day 6 was not affected by 10 mM ethionine treatment. S-adenosylmethionine (SAM) added to the ethionine treatment partly restored the blastocyst development. Semiquantitative reverse transcription-polymerase chain reaction analysis of cell lineage-related transcription factors in day 6 compacted morulae showed that the expressions of NANOG and TEAD4 were increased by ethionine treatment relative to the control (P<0.01). Furthermore, immunofluorescence analysis of 5-methylcytosine revealed that DNA was hypomethylated in the ethionine-treated day 6 morulae compared with the control (P<0.001). These results demonstrate that the disruption of methionine metabolism causes impairment of the morula-to-blastocyst transition during bovine preimplantation development in part via SAM deficiency, indicating the indispensable roles of methionine during this period. The disruption of methionine metabolism may cause hypomethylation of DNA and consequently lead to the altered expression of developmentally important genes, which then results in the impairment of blastocyst development. PMID:22052008

Ikeda, Shuntaro; Sugimoto, Miki; Kume, Shinichi

2011-11-04

242

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

243

Synthesis, Transfer, and Devices of Single and Few-Layer Graphene by Chemical Vapor Deposition  

Microsoft Academic Search

The advance of graphene-based nanoelectronics has been hampered due to the difficulty in producing single- or few-layer graphene over large areas. We report a simple, scalable, and cost-efficient method to prepare graphene using methane-based CVD on nickel films deposited over complete Si\\/SiO2 wafers. By using highly diluted methane, single- and few-layer graphene were obtained, as confirmed by micro-Raman spectroscopy. In

Lewis Gomez De Arco; Yi Zhang; Akshay Kumar; Chongwu Zhou

2009-01-01

244

Inner-sphere electron-transfer single iodide mechanism for dye regeneration in dye-sensitized solar cells.  

PubMed

During the regeneration of the oxidized dye in dye-sensitized solar cells, the redox couple of I(-)/I(3)(-) reduces the photo-oxidized dye. The simplest mechanism would be a direct charge-transfer mechanism from I(-) to D(+) [D(+) + I(-) ? D(0) + I], called the single iodide process (SIP). However, this is an unfavorable equilibrium because the redox potential of I(•)/I(-) is 1.224 V vs SHE, which is 0.13 V higher than that of the dye. This led to the postulation of the two iodide process (TIP) [(D(+)···I(-)) + I(-) ? (D···I(2)(-)) ? D(0) + I(2)(-))] for a sufficiently high reducing power, but TIP is not consistent with either the recent experimental data suggesting the first-order kinetics or recent time-resolved spectroscopic measurements. To resolve this conundrum, we used quantum mechanics including Poisson-Boltzmann solvation to examine the electron-transfer process between I(-) and D(+) for the Ru(dcb)(2)NCS(2) or N3 dye. We find that I(-) is attracted to the oxidized dye, positioning I(-) next to the NCS. At this equilibrium position, the I(-) electron is already 40% transferred to the NCS, showing that the redox potential of I(-) is well matched with the dye. This matching of the redox potential occurs because I(-) is partially desolvated as it positions itself for the inner-sphere electron transfer (ISET). The previous analyses all assumed an outer-sphere electron-transfer process. Thus our ISET-SIP model is consistent with the known redox potentials and with recent experimental reports. With the ISET-SIP mechanism, one can start to consider how to enhance the dye regeneration kinetics by redesigning ligands to maximize the interaction with iodide. PMID:23384053

Jeon, Jiwon; Goddard, William A; Kim, Hyungjun

2013-02-11

245

High-frequency phage-mediated gene transfer among Escherichia coli cells, determined at the single-cell level.  

PubMed

Recent whole-genome analysis suggests that lateral gene transfer by bacteriophages has contributed significantly to the genetic diversity of bacteria. To accurately determine the frequency of phage-mediated gene transfer, we employed cycling primed in situ amplification-fluorescent in situ hybridization (CPRINS-FISH) and investigated the movement of the ampicillin resistance gene among Escherichia coli cells mediated by phage at the single-cell level. Phages P1 and T4 and the newly isolated E. coli phage EC10 were used as vectors. The transduction frequencies determined by conventional plating were 3x10(-8) to 2x10(-6), 1x10(-8) to 4x10(-8), and <4x10(-9) to 4x10(-8) per PFU for phages P1, T4, and EC10, respectively. The frequencies of DNA transfer determined by CPRINS-FISH were 7x10(-4) to 1x10(-3), 9x10(-4) to 3x10(-3), and 5x10(-4) to 4x10(-3) for phages P1, T4, and EC10, respectively. Direct viable counting combined with CPRINS-FISH revealed that more than 20% of the cells carrying the transferred gene retained their viabilities. These results revealed that the difference in the number of viable cells carrying the transferred gene and the number of cells capable of growth on the selective medium was 3 to 4 orders of magnitude, indicating that phage-mediated exchange of DNA sequences among bacteria occurs with unexpectedly high frequency. PMID:17384307

Kenzaka, Takehiko; Tani, Katsuji; Sakotani, Akiko; Yamaguchi, Nobuyasu; Nasu, Masao

2007-03-23

246

Photobleaching-Based Quantitative Analysis of Fluorescence Resonance Energy Transfer inside Single Living Cell  

Microsoft Academic Search

The current advances of fluorescence microscopy and new fluorescent probes make fluorescence resonance energy transfer (FRET)\\u000a a powerful technique for studying protein-protein interactions inside living cells. It is very hard to quantitatively analyze\\u000a FRET efficiency using intensity-based FRET imaging microscopy due to the presence of autofluorescence and spectral crosstalks.\\u000a In this study, we for the first time developed a novel

Longxiang Wang; Tongsheng Chen; Junle Qu; Xunbin Wei

2010-01-01

247

Charge transfer through single molecule contacts: How reliable are rate descriptions?  

PubMed

Background: The trend for the fabrication of electrical circuits with nanoscale dimensions has led to impressive progress in the field of molecular electronics in the last decade. However, a theoretical description of molecular contacts as the building blocks of future devices is challenging, as it has to combine the properties of Fermi liquids in the leads with charge and phonon degrees of freedom on the molecule. Outside of ab initio schemes for specific set-ups, generic models reveal the characteristics of transport processes. Particularly appealing are descriptions based on transfer rates successfully used in other contexts such as mesoscopic physics and intramolecular electron transfer. However, a detailed analysis of this scheme in comparison with numerically exact solutions is still elusive.Results: We show that a formulation in terms of transfer rates provides a quantitatively accurate description even in domains of parameter space where strictly it is expected to fail, e.g., at lower temperatures. Typically, intramolecular phonons are distributed according to a voltage driven steady state that can only roughly be captured by a thermal distribution with an effective elevated temperature (heating). An extension of a master equation for the charge-phonon complex, to effectively include the impact of off-diagonal elements of the reduced density matrix, provides very accurate solutions even for stronger electron-phonon coupling.Conclusion: Rate descriptions and master equations offer a versatile model to describe and understand charge transfer processes through molecular junctions. Such methods are computationally orders of magnitude less expensive than elaborate numerical simulations that, however, provide exact solutions as benchmarks. Adjustable parameters obtained, e.g., from ab initio calculations allow for the treatment of various realizations. Even though not as rigorously formulated as, e.g., nonequilibrium Green's function methods, they are conceptually simpler, more flexible for extensions, and from a practical point of view provide accurate results as long as strong quantum correlations do not modify the properties of the relevant subunits substantially. PMID:22003449

Kast, Denis; Kecke, L; Ankerhold, J

2011-08-03

248

The absence of a Ca(2+) signal during mouse egg activation can affect parthenogenetic preimplantation development, gene expression patterns, and blastocyst quality.  

PubMed

A series of Ca(2+) oscillations during mammalian fertilization is necessary and sufficient to stimulate meiotic resumption and pronuclear formation. It is not known how effectively development continues in the absence of the initial Ca(2+) signal. We have triggered parthenogenetic egg activation with cycloheximide that causes no Ca(2+) increase, with ethanol that causes a single large Ca(2+) increase, or with Sr(2+) that causes Ca(2+) oscillations. Eggs were co-treated with cytochalasin D to make them diploid and they formed pronuclei and two-cell embryos at high rates with each activation treatment. However, far fewer of the embryos that were activated by cycloheximide reached the blastocyst stagecompared tothose activated by Sr(2+) orethanol. Any cycloheximide-activated embryos that reached the blastocyst stage had a smaller inner cell mass number and a greater rate of apoptosis than Sr(2+)-activated embryos. The poor development of cycloheximide-activated embryos was due to the lack of Ca(2+) increase because they developed to blastocyst stages at high rates when co-treated with Sr(2+) or ethanol. Embryos activated by either Sr(2+) or cycloheximide showed similar signs of initial embryonic genome activation (EGA) when measured using a reporter gene. However, microarray analysis of gene expression at the eight-cell stage showed that activation by Sr(2+) leads to a distinct pattern of gene expression from that seen with embryos activated by cycloheximide. These data suggest that activation of mouse eggs in the absence of a Ca(2+) signal does not affect initial parthenogenetic events, but can influence later gene expression and development. PMID:16816332

Rogers, N T; Halet, G; Piao, Y; Carroll, J; Ko, M S H; Swann, K

2006-07-01

249

Correlated blinking via time dependent energy transfer in single CdSe quantum dot-dye nanoassemblies  

NASA Astrophysics Data System (ADS)

Optical confocal spectroscopy on self-assembled single nanoassemblies from CdSe/ZnS quantum dots (QD) and perylene diimide dye molecules demonstrates efficient Förster resonance energy transfer (FRET). Intramolecular dynamics of the flexible dye molecule change the FRET efficiency in course of the detection period of several minutes. This can be followed by correlated observations of luminescence intensities and related spectral shifts of both constituents. Contrary to several experiments on similar assemblies, the FRET efficiencies are by almost one order of magnitude larger in the non-polar liquid solvent TEHOS as compared e.g. to toluene. Experimental and theoretically expected efficiencies are in close agreement with each other.

Gerlach, Frank; Täuber, Daniela; von Borczyskowski, Christian

2013-05-01

250

Controlling Optimal Excitation Wavelength of Energy Transfer from Photo-Excited Polymers to Single-Walled Carbon Nanotubes.  

NASA Astrophysics Data System (ADS)

The optimal excitation wavelength for the energy transfer from aromatic polymers poly(9,9-dioctylfluoreny- 2,7-diyl) (PFO) to single-walled carbon nanotubes (SWNTs) is tunable in a wide wavelength range (from 388 to 480 nm) depending on the concentration of excess PFO polymers. The concentration governs the aggregation state and chain conformation of the polymers proximate to SWNT surfaces, which in turn alters the optimal excitation wavelength. This study suggests an exciting and convenient method of adjusting the desired optical wavelengths for the energy conversion, useful for polymer-SWNT composites in optoelectronic applications.

Li, Lain-Jong; Chen, Fuming; Jia, Mingli; Wei, Li; Chen, Yuan; Chan-Park, M. B.; Xia, Andong

2009-03-01

251

Direct observation of resonant energy transfer between quantum dots of two different sizes in a single water droplet  

NASA Astrophysics Data System (ADS)

Water soluble CdTe nanocrystals (NCs) of two different sizes capped by thioglycolic acid were synthesized and were dispersed in pure water. We have observed that the emission color of CdTe NCs has been changed in a single droplet of water during the evaporation of the solvent. This is attributed to Förster resonance energy transfer between CdTe NCs, when their concentration becomes high enough to ensure close proximity. By combining our results of photoluminescence with quantitative analysis we conclude that the coupling between different sized CdTe NCs via long-range dipole-dipole interactions was enhanced in aqueous solution due to Brownian motion.

Xu, Ling; Xu, Jun; Ma, Zhongyuan; Li, Wei; Huang, Xinfan; Chen, Kunji

2006-07-01

252

Effects of donor fibroblasts expressing OCT4 on bovine embryos generated by somatic cell nuclear transfer.  

PubMed

The production of healthy, live, cloned animals by somatic cell nuclear transfer (SCNT) has been hampered by low efficiencies. Significant epigenetic changes must take place to ensure proper chromatin remodeling in SCNT. We hypothesized that exogenous expression of OCT4 in donor fibroblasts prior to its fusion with enucleated oocytes would facilitate SCNT reprogramming. We infected bovine adult fibroblasts with retroviral vectors containing yellow fluorescent protein (YFP) only, or the OCT4 gene fused to YFP (YO). We found that development to the blastocyst stage was not different between NT-YFP and NT-YO groups. NT-YFP embryos had the fewest trophoblast cells, measured by numbers of CDX2-positive cells. Fibroblasts expressing OCT4 had reduced levels of histone 3 lysine 9 or 27 trimethylation (H3K9me3 and H3K27me3, respectively). NT-YO blastocysts displayed higher H3K9me3 levels than IVF and NT-YFP embryos; however, they did not have different H3K27me3 levels. Levels of XIST mRNA expression in NT-YO and NT-YF were higher when compared to in vitro-fertilized blastocysts. We observed no differences in the expression of SOX2, NANOG, and CDX2. Although overexpression of OCT4 in donor cells increased H3K9me3 and did not reduce XIST gene expression, we show that a single transcription factor can affect the number of trophectoderm cells in bovine SCNT embryos. PMID:23276226

Goissis, Marcelo D; Suhr, Steven T; Cibelli, Jose B

2012-12-31

253

Fatty acid composition of lipids in day 7–13 blastocysts, serum and uterine fluid of rabbits  

Microsoft Academic Search

Purpose  The fatty acid composition of rabbit blastocysts, blood serum and uterine fluids were analyzed to study embryonic lipid metabolism.\\u000a \\u000a \\u000a \\u000a Methods  Embryos were collected from Japanese white rabbits and fatty acids were analyzed by gas chromatograph.\\u000a \\u000a \\u000a \\u000a Results  Total amount of fatty acids in blastocysts was higher than that in serum and uterine fluid. The amount of fatty acids in blastocysts\\u000a markedly decreased during

Hirotada Tsujii; Y. Matsuoka; R. Obata; M. S. Hossain; Y. Takagi

2009-01-01

254

Importance of Thomas single-electron transfer in fast p-He collisions  

NASA Astrophysics Data System (ADS)

We report experimental angular differential cross sections for nonradiative single-electron capture in p-He collisions (p+ He ? H + He+) with a separate peak at the 0.47 mrad Thomas scattering angle for energies in the 1.3-12.5 MeV range. We find that the intensity of this peak scales with the projectile velocity as vP-11. This constitutes the first experimental test of the prediction from 1927 by L. H. Thomas [Proc. R. Soc. 114, 561 (1927)]. At our highest energy, the peak at the Thomas angle contributes with 13.5% to the total integrated nonradiative single-electron capture cross section.

Fischer, D.; Gudmundsson, M.; Berényi, Z.; Haag, N.; Johansson, H. A. B.; Misra, D.; Reinhed, P.; Källberg, A.; Simonsson, A.; Støchkel, K.; Cederquist, H.; Schmidt, H. T.

2010-01-01

255

Studies of nuclei close to 132Sn using single-neutron transfer reactions  

NASA Astrophysics Data System (ADS)

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. J.; Pain, S. D.; Kozub, R. L.; Adekola, A. S.; Bardayan, D. W.; Blackmon, J. C.; Catford, W. N.; Chae, K. Y.; Chipps, K.; Cizewski, J. A.; Erikson, L.; Gaddis, A. L.; Greife, U.; Grzywacz, R.; Harlin, C.; Hatarik, R.; Howard, J. A.; James, J.; Kapler, R.; Królas, W.; Liang, J. F.; Ma, Z.; Matei, C.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Patterson, N. P.; Paulauskas, S. V.; Shapira, D.; Shriner, J. F.; Sikora, M.; Sissom, D. J.; Smith, M. S.; Swan, T. P.; Thomas, J. S.; Wilson, G. L.

2009-03-01

256

Monozygotic twins with discordant karyotypes following preimplantation genetic screening and single embryo transfer: case report  

Microsoft Academic Search

Purpose  To report a case of monozygotic monochorial diamniotic twins with discordant karyotypes.\\u000a \\u000a \\u000a \\u000a Methods and results  The pregnancy was achieved following a treatment cycle with intracytoplasmic sperm injection (ICSI) and preimplantation genetic\\u000a screening (PGS) for chromosomes X, Y, 13, 16, 18, 21, 22. One embryo euploid for studied chromosomes was transferred. Prenatal\\u000a ultrasonography revealed monozygotic twins. One fetus had growth retardation, multiple

Gabriela Tauwinklova; Renata Gaillyova; Pavel Travnik; Eva Oracova; Katerina Vesela; Lenka Hromadova; Jan Vesely; Petra Musilova; Jiri Rubes; Jitka Kadlecova; Iva Slamova; Eva Makaturova; Vladimira Vranova

2010-01-01

257

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

2012-12-05

258

On-demand single-electron transfer between distant quantum dots with nanosecond pulses of surface acoustic waves  

NASA Astrophysics Data System (ADS)

Quantum dots (QDs) provide a useful system for manipulating and storing quantum information. Methods for moving quantum information (spin) between processor and storage, or to a region of holes for conversion to photon qubits, will be required. Tunnelling of electrons over long distances between QDs is not viable. We show controlled long-range transfer of single electrons between QDs through a depleted 1D channel using pulses of surface acoustic waves (SAWs). In our device, two QDs are connected by a 4?m channel with QD occupancy monitored by 1D charge detectors. Electrons may be trapped and raised above the Fermi energy by stepping gate voltages. Having set the first QD to be `full' and the other QD `empty', a short SAW pulse is sent to transfer the electron to the opposite QD. This bi-directional process may be repeated over 100 times with the same electron. SAW power and pulse-width dependences suggest that transfer is achieved during the first few SAW cycles allowing sub-20ns pulses to be used.

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

2011-03-01

259

Extracting protein folding kinetics in single-pair fluorescence resonance energy transfer experiment based on wavelet analysis  

NASA Astrophysics Data System (ADS)

Dynamic structural changes of protein folding and biological macromolecules undergoing biochemical reactions can be monitored and studied using the single-pair fluorescence resonance energy transfer (sp-FRET) spectroscopy tool. In this work, we have simulated a single-pair FRET photoemission process as an illustrative model example, where a FRET pair resides on a folding protein that undergoes diffusion in water. And then we apply the wavelet analysis method, which is a widely used method in many fields, such as the digital signal processing, noise reduction and the data compression (JPEG2000), to deal with the case of fluorescence resonance energy transfer (FRET) experiment for protein folding. It is shown that the wavelet analysis filter facilitates the detection of various intermediate conformational states in a noisy trajectory. Thus it is finally suggested that it is particularly suitable for sp-FRET spectroscopy studies of protein folding and can be of use for directly extracting the folding energy landscape. Our study establishes potentially useful data analysis technique and theoretical guidelines for the study of sp-FRET spectroscopy experiments.

Shan, Guangcun; Huang, Wei

2007-01-01

260

The Effects of Perioperative Analgesia on Litter Size in Crl:CD1(ICR) Mice Undergoing Embryo Transfer  

PubMed Central

The objective of this study was to evaluate the effect on litter size of 2 analgesics used perioperatively during mouse embryo transfer surgery. Day 2.5 pseudopregnant CD1 mice (n = 96) were divided equally into 2 analgesic treatment groups and a saline control group. Each mouse received a single, subcutaneous dose of buprenorphine hydrochloride (0.1 mg/kg), flunixin meglumine (2.5 mg/kg), or saline immediately after induction of anesthesia with 2.5% isoflurane. Each mouse then was prepared for aseptic surgery. Blastocysts had previously been collected from C57BL/6NCrl female mice that were synchronized and superovulated by using pregnant mare serum gonadotropin and human chorionic gonadotropin and mated with C57BL/6NTac male mice 3.5 d before collection. Viable blastocysts were pooled, and 8 were selected arbitrarily and transplanted into the right uterine horn of each pseudopregnant CD1 mouse. Mice were monitored throughout pregnancy, and the number of pups at birth was documented. No statistically significant difference was found between the 3 groups. These results indicate that perioperative analgesic treatment with buprenorphine or flunixin in the CD1 mouse undergoing embryo transfer is not associated with increased embryonic loss.

Goulding, David R; Myers, Page H; Goulding, Eugenia H; Blankenship, Terry L; Grant, Mary F; Forsythe, Diane B

2010-01-01

261

In vivo single-cell electroporation for transfer of DNA and macromolecules  

Microsoft Academic Search

Single-cell electroporation allows transfection of plasmid DNA or macrocmolecules into individual living cells using modified patch electrodes and common electrophysiological equipment. This protocol is optimized for rapid in vivo electroporation of Xenopus laevis tadpole brains with DNA, dextrans, morpholinos and combinations thereof. Experienced users can electroporate roughly 40 tadpoles per hour. The technique can be adapted for use with other

Jennifer E Bestman; Rebecca C Ewald; Shu-Ling Chiu; Hollis T Cline

2006-01-01

262

Film transfer and bonding techniques for covering single-chip ejector array with microchannels and reservoirs  

Microsoft Academic Search

This paper describes a novel covering technique for an MEMS ejector array that is integrated with liquid reservoirs and microchannels on a single chip. The covering technique is based on wicking of a low viscous epoxy through the gap between the ejector wafer and a plate containing a parylene film, and allows the integrated ejector array to be fully covered

Jae Wan Kwon; Hongyu Yu; Eun Sok Kim

2005-01-01

263

Charge Transfer through Single-Stranded Peptide Nucleic Acid Composed of Thymine Nucleotides  

Microsoft Academic Search

Self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids (PNAs) containing 3 to 7 thymine (T) nucleotides, a C-terminus cysteine, and an N-terminus ferrocene group were formed on gold electrodes. The existence of two redox environments for the ferrocene was detected by cyclic voltammetry and was attributed to the presence of \\

Amit Paul; Richard M. Watson; Paul Lund; Yangjun Xing; Kathleen Burke; Yufan He; Eric Borguet; Catalina Achim; David H. Waldeck

2008-01-01

264

Low-pressure airlift fermenter for single cell protein production. I. Design and oxygen transfer studies  

Microsoft Academic Search

The energy consumption of a fermenter constitutes a major part of the operating expense of a single cell protein process. A low-pressure airlift fermenter was designed to reduce this cost. In this new design, the fermenter broth is kept below 120 cm in depth, and air alone is employed to fulfil the need of supplying oxygen, and cooling and agitating

N. Y. Chen; E. F. Kondis; S. Srinivasan

1987-01-01

265

Unraveling electronic energy transfer in single conjugated polyelectrolytes encapsulated in lipid vesicles  

PubMed Central

A method for the study of conjugated polyelectrolyte (CPE) photophysics in solution at the single-molecule level is described. Extended observation times of single polymer molecules are enabled by the encapsulation of the CPEs within 200-nm lipid vesicles, which are in turn immobilized on a surface. When combined with a molecular-level visualization of vesicles and CPE via cryo-transmission electron microscopy, these single-molecule spectroscopy studies on CPEs enable us to directly correlate the polymer conformation with its spectroscopic features. These studies are conducted with poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylene-vinylene] (MPS-PPV, a negatively charged CPE), when encapsulated in neutral and in negatively charged lipid vesicles. MPS-PPV exists as a freely diffusing polymer when confined in negatively charged vesicles. Individual MPS-PPV molecules adopt a collapsed-chain conformation leading to efficient energy migration over multiple chromophores. Both the presence of stepwise photobleaching in fluorescence intensity-time trajectories and emission from low-energy chromophores along the chain are observed. These results correlate with the amplified sensing potential reported for MPS-PPV in aqueous solution. When confined within neutral vesicles, single MPS-PPV molecules adopt an extended conformation upon insertion in the lipid bilayer. In this case emission arises from multiple chromophores within the isolated polymer chains, leading to an exponential decay of the intensity over time and a broad blue-shifted emission spectrum.

Karam, Pierre; Ngo, An Thien; Rouiller, Isabelle; Cosa, Gonzalo

2010-01-01

266

Minimum action paths for single domain ferromagnetic nanostructures under the influence of spin transfer torque  

NASA Astrophysics Data System (ADS)

Thermally induced magnetization reversal is an important issue for the design of magnetic storage devices. The problem is usually studied using Kramers' theory of reaction rates, which is applicable when the dynamics can be described as gradient forces. Spin Transfer Torque (STT) is an effect of technological importance which does not fall in this category. For Spin Transfer Torque an action minimization is required to find the most probable paths and transition states between metastable states. We calculate these most probable paths for ferromagnetic nanostructures under the influence of STT in the low noise limit for a variety of current strengths and magnetic fields. Previous action minimization were done in the absence of STT and provide a good basis for comparison [1]. We study thin films with an in-plane easy magnetization axis using the geometrical Minimum Action Method (gMAM) [2]. The action obtained using gMAM is in qualitative agreement with activation energy barriers on previous work by Li-Zhang [3].[4pt] [1] R.V. Kohn, M.G. Reznikoff, E. Vanden-Eijnden, J. Nonlinear Sci. 15, 223 (2005)[0pt] [2] M. Heymann, E. Vanden-Eijnden, Comm. Pure Appl. Math. LXI, 1052(2008)[0pt] [3] Z. Li, S. Zhang, Phys. Rev. B 69, 134416 (2004)

Chaves-O'Flynn, Gabriel; Stein, Daniel; Kent, Andrew; vanden-Eijnden, Eric

2011-03-01

267

Importance of Thomas single-electron transfer in fast p-He collisions  

SciTech Connect

We report experimental angular differential cross sections for nonradiative single-electron capture in p-He collisions (p+ He -> H + He{sup +}) with a separate peak at the 0.47 mrad Thomas scattering angle for energies in the 1.3-12.5 MeV range. We find that the intensity of this peak scales with the projectile velocity as v{sub P}{sup -11}. This constitutes the first experimental test of the prediction from 1927 by L. H. Thomas [Proc. R. Soc. 114, 561 (1927)]. At our highest energy, the peak at the Thomas angle contributes with 13.5% to the total integrated nonradiative single-electron capture cross section.

Fischer, D. [Department of Physics, Stockholm University, S-10691 Stockholm (Sweden); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1 D-69126 (Germany); Gudmundsson, M.; Berenyi, Z.; Haag, N.; Johansson, H. A. B.; Misra, D.; Reinhed, P.; Cederquist, H. [Department of Physics, Stockholm University, S-10691 Stockholm (Sweden); Kaellberg, A.; Simonsson, A.; Schmidt, H. T. [Manne Siegbahn Laboratory, Stockholm University, S-11418 Stockholm (Sweden); Stoechkel, K. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2010-01-15

268

Electron Transfer between Cytochrome C and Cytochome C Peroxidase in Single Crystals  

SciTech Connect

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.

Kang, Seong A.; Marjavaara, Pieti J.; Crane, Brian R. (Cornell)

2010-11-10

269

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 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. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

Chinthavali, Madhu Sudhan [ORNL; Onar, Omer C [ORNL; Miller, John M [ORNL; Tang, Lixin [ORNL

2013-01-01

270

Midgestational Abnormalities Associated with in vitro Preimplantation N-methyl-N-nitrosourea Exposure with Subsequent Transfer to Surrogate Mothers  

Microsoft Academic Search

Mouse blastocyst functions have been shown to be disrupted by in vitro exposure to N-methyl-N-nitrosourea (MeNU). After exposure, the chemically treated blastocysts were transferred to the uteri of pseudopregnant surrogate mothers. Implantation rate and birth rate have been shown previously to decrease in a concentration-dependent manner. Because of the large progressive decrease in the 50% effective concentration (EC50) for cytotoxicity,

N. L. Bossert; P. M. Iannaccone

1985-01-01

271

Vitrified blastocysts from Preimplantation Genetic Diagnosis (PGD) as a source for human Embryonic Stem Cell (hESC) derivation.  

PubMed

Embryos diagnosed as abnormal in Preimplantation Genetic Diagnosis (PGD) cycles are useful for the establishment of human Embryonic Stem Cells (hESC) lines with genetic disorders. These lines can be helpful for drug screening and for the development of new treatments. Vitrification has proved to be an efficient method to preserve human blastocysts. One hundred and three abnormal or undiagnosed vitrified blastocysts from the PGD programme at Institut Universitari Dexeus were donated for human embryonic stem cell derivation. The overall survival rate after warming was 70.6 %. Our results showed better survival rates when blastocysts have not started the hatching process (initial/expanded 87.8 %, hatching 68.3 % and hatched 27.3 %). Thirty-five blastocysts and 12 partially surviving embryos were seeded. One hESC line with the multiple exostoses type 2 paternal mutation was obtained. PMID:22735930

Aran, Begoña; Sole, Miquel; Rodriguez-Pizà, Ignasi; Parriego, Mònica; Muñoz, Yolanda; Boada, Montserrat; Barri, Pere N; Izpisúa, Juan Carlos; Veiga, Anna

2012-06-27

272

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

273

The behaviour of cow blastocyst in vitro: cinematographic and morphometric analysis.  

PubMed Central

The behaviour of the cow blastocyst in vitro was studied by time-lapse cinematography and analysed by morphometry. Three types of behaviour were observed: continuous expansion followed by hatching; discontinuous expansion interrupted by few contractions and followed by hatching; discontinuous expansion interrupted by several rapid contractions without hatching. This demonstrated that the pulsatile activity of the blastocyst is not a necessary condition of hatching but also that only a moderate pulsatile activity is compatible with normal hatching. The time of hatching in vitro corresponded approximately with the time of zona loss in vivo (9-10 days). Rupture of the zona occurred at any point of the trophoblast layer. Hatching by herniation through a reduced opening of the zona was occasionally observed. The behavior of the embryos from a particular animal was very similar but differences were noted between embryos from different animals. Images Fig. 3

Massip, A; Mulnard, J; Vanderzwalmen, P; Hanzen, C; Ectors, F

1982-01-01

274

Developmental Competence of Frozen-thawed Blastocysts from Fair-quality Bovine Embryos Cultured with ?-Mercaptoethanol  

Microsoft Academic Search

Two-hundred-and-thirty-one fair-quality embryos at the compacted morula stage collected from 89 superovulated cows were cultured in TCM199 or Brinster’s BMOC-3 medium with or without 100 ?M ?-mercaptoethanol (?-ME). After 24 h culture, a total of 142 fair-quality embryos developed to the blastocyst stage, of which 106 were subsequently frozen with 1.8 M ethylene glycol. The mean cell number and development

T. OTOI; N. KOYAMA; K. YAMAMOTO; N. HORIKITA; S. TACHIKAWA; T. SUZUKI

2000-01-01

275

Patient-Specific Stem Cell Lines Derived from Human Parthenogenetic Blastocysts  

Microsoft Academic Search

Parthenogenetic activation of human oocytes may be one way to produce histocompatible cells for cell-based therapy. We report the successful derivation of six pluripotent human em- bryonic stem cell (hESC) lines from blastocysts of parthenogenetic origin. The parthenogenetic human embryonic stem cells (phESC) demonstrate typical hESC morphology, express appro- priate markers, and possess high levels of alkaline phosphatase and telomerase

E. S. Revazova; N. A. Turovets; O. D. Kochetkova; L. B. Kindarova; L. N. Kuzmichev; J. D. Janus; M. V. Pryzhkova

2007-01-01

276

Promotion of gastrulation by maternal growth factor in cultured rabbit blastocysts  

Microsoft Academic Search

Rabbit blastocysts of day 6 post coitum were cultured in a chemically defined, protein-free medium for 24 h. Although the trophoblast continued to grow, the embryonic disc degenerated. Addition of basic fibroblast growth factor (FGF-2, of human recombinant or bovine origin, 10 ng\\/ml) to the culture medium resulted in significant developmental progress. The embryonic disc became pear-shaped showing a round

M. Hrabé Angelis; C. Gründker; B. G. Herrmann; A. Kispert; C. Kirchner

1995-01-01

277

Room-temperature-operating data processing circuit based on single-electron transfer and detection with metal-oxide-semiconductor field-effect transistor technology  

NASA Astrophysics Data System (ADS)

A single-electron-based circuit, in which electrons are transferred one by one with a turnstile and subsequently detected with a high-charge-sensitivity electrometer, was fabricated on a silicon-on-insulator substrate. The turnstile, which is operated by opening and closing two metal-oxide-semiconductor field-effect transistors alternately, allows single-electron transfer at room temperature owing to electric-field-assisted shrinkage of the single-electron box. It also achieves fast single-electron transfer (less than 10 ns) and extremely long retention (more than 104 s). We have applied these features to a multilevel memory and a time-division weighted sum circuit for a digital-to-analog converter.

Nishiguchi, Katsuhiko; Fujiwara, Akira; Ono, Yukinori; Inokawa, Hiroshi; Takahashi, Yasuo

2006-05-01

278

Dynamics of the Load Transfer in a Single Straight Chain of Disks: FEM Simulations  

NASA Astrophysics Data System (ADS)

The wave propagation phenomenon in a single straight chain of disks made of PSM9 was simulated numerically using the finite element code ABAQUS. The results yield information on the stress wave propagation along the chain. Qualitative agreement with experimental data that was obtained using an optical method of dynamic photo-elasticity and strain gages was obtained. The results of the comparison clearly demonstrate that the stress propagation phenomena are largely governed by the quality of the contacts between the disks. Based on the obtained results justifications for further research efforts on this subject are presented.

Goldenberg, A.; Britan, A.; Ben-Dor, G.; Igra, O.; Hariton, I.; Glam, B.

2004-07-01

279

Charge transfer along localized states in InSe and InSe single crystals  

NASA Astrophysics Data System (ADS)

It is established that at temperatures T<200 K hopping conductivity with variable hopping length exists across natural layers of undoped and doped (0.2 and 0.4 at % Sn) InSe single crystals in a constant electric field. The density of states near the Fermi level (NF=5.36.1018-1.72.1019 eV-1.cm-3), the energy spread of the states (?E=0.028-0.040 eV), the localization radius (a=58 A?), and the average hopping length (Rav=99.5-130 A?) in the temperature interval 100-200 K are evaluated.

Mustafaeva, S. N.; Isma?lov, A. A.; Asadov, M. M.

2010-04-01

280

Photoinduced electron transfer (PET)-probes for the study of enzyme activity at the ensemble and single molecule level  

NASA Astrophysics Data System (ADS)

Fluorescence based enzyme analysis is commonly done by FRET-probes, natural enzyme substrates flanked by two corresponding fluorophores, showing spectral changes upon distance variations between the fluorophores. However, the use of double labeled substrates displays several limitations such as reduction of sensitivity and high background signal accompanied by high costs for synthesis. Therefore, the development of new probes avoiding these factors is of general interest in enzyme research. A promising approach represents smart probes, i.e. singly labeled quenched enzyme substrates that increase fluorescence intensity upon enzymatic cleavage. Smart probes use the fact that certain rhodamine and oxazine dyes are selectively quenched upon contact formation with guanine or tryptophan residues via photoinduced electron transfer (PET). The rapid response time of the probes enables real-time monitoring of enzyme activity in ensemble as well as in single molecule measurements, which is an important prerequisite for the improved understanding of enzyme mechanisms. We present the design of smart probes for the detection of the two hydrolases, DNaseI and Carboxypeptidase A (CPA) with respect to stability and substrate specificity in ensemble measurements. Furthermore, we investigate the influence of the attached fluorophore on hydrolysis efficiency in case of CPA and demonstrate first applications of smart probes in single enzyme experiments.

Henkenjohann, Sigrun; van de Linde, Sebastian; Doose, Sören; Tinnefeld, Philip; Sauer, Markus

2007-06-01

281

Resveratrol Protects against 2-Bromopropane-Induced Apoptosis and Disruption of Embryonic Development in Blastocysts  

PubMed Central

2-Bromopropane (2-BP) is used as an alternative to ozone-depleting cleaning solvents. Previously, we reported that 2-BP has cytotoxic effects on mouse blastocysts and is associated with defects in subsequent development. In the present work, we show that 2-BP induces apoptosis in the inner cell mass of mouse blastocysts, and inhibits cell proliferation. Both effects are suppressed by resveratrol, a grape-derived phytoalexin with known antioxidant and anti-inflammatory properties. 2-BP-treated blastocysts displayed lower levels of implantation (compared to controls) when plated on culture dishes in vitro, and a reduced ability to proceed to later stages of embryonic development. Pretreatment with resveratrol prevented 2-BP-induced disruption of embryonic development, both in vitro and in vivo. Further investigation of these processes revealed that 2-BP directly promotes ROS generation, loss of mitochondrial membrane potential (MMP), and activation of caspase-3, whereas resveratrol effectively blocks 2-BP-induced ROS production and the accompanying apoptotic biochemical changes. Our results collectively imply that 2-BP triggers the mitochondrion-dependent apoptotic pathway via ROS generation, and the antioxidant activity of resveratrol prevents 2-BP-induced toxicity.

Chan, Wen-Hsiung

2011-01-01

282

The first cleavage of the mouse zygote predicts the blastocyst axis.  

PubMed

One of the unanswered questions in mammalian development is how the embryonic-abembryonic axis of the blastocyst is first established. It is possible that the first cleavage division contributes to this process, because in most mouse embryos the progeny of one two-cell blastomere primarily populate the embryonic part of the blastocyst and the progeny of its sister populate the abembryonic part. However, it is not known whether the embryonic-abembryonic axis is set up by the first cleavage itself, by polarity in the oocyte that then sets the first cleavage plane with respect to the animal pole, or indeed whether it can be divorced entirely from the first cleavage and established in relation to the animal pole. Here we test the importance of the orientation of the first cleavage by imposing an elongated shape on the zygote so that the division no longer passes close to the animal pole, marked by the second polar body. Non-invasive lineage tracing shows that even when the first cleavage occurs along the short axis imposed by this experimental treatment, the progeny of the resulting two-cell blastomeres tend to populate the respective embryonic and abembryonic parts of the blastocyst. Thus, the first cleavage contributes to breaking the symmetry of the embryo, generating blastomeres with different developmental characteristics. PMID:15772664

Plusa, Berenika; Hadjantonakis, Anna-Katerina; Gray, Dionne; Piotrowska-Nitsche, Karolina; Jedrusik, Agnieszka; Papaioannou, Virginia E; Glover, David M; Zernicka-Goetz, Magdalena

2005-03-17

283

Effect of fragment removal on blastocyst formation and quality of human embryos.  

PubMed

Blastomere fragmentation is one of the most significant defects in cleaving embryos. Scientists believed that removing the fragments was a possible way to reduce their unwanted effects. This hypothesis has been tested in some studies in which the development of human fragmented embryos was followed in vivo after all fragments were removed, but little is known about the potential for in-vitro development of such embryos, which is the subject of the present study. For this purpose, 4-6 cell surplus human embryos were scored according to the degree and pattern of fragmentation into four grades, allocated into two groups of control and fragmentation removal (experimental) and cultured sequentially. At the end of day 6 of culture, in the experimental group especially in grade IV blastocyst rate, size and number of blastomeres in each blastocyst were all improved compared with those of the control group (42.3 versus 20.0%; 19,205.7 +/- 1060.3 versus 15,825.9 +/- 448.7 microm(2) and 100.14 +/- 13.48 versus 63.75 +/- 19.79 respectively, P < 0.05). In the grade IV embryos, apoptotic index was also significantly reduced after embryo fragmentation removal (3.40 +/- 0.88 versus 22.99 +/- 4.45, P < 0.05). In conclusion, fragmentation removal had a positive effect on human fragmented embryos and produced the best quality blastocysts. PMID:17169204

Eftekhari-Yazdi, Poopak; Valojerdi, Mojtaba Rezazadeh; Ashtiani, Saeed Kazemi; Eslaminejad, Mohamadreza Baghaban; Karimian, Leila

2006-12-01

284

Nanoscopic heterogeneities in adsorption and electron transfer processes of perylene diimide dye on TiO 2 nanoparticles studied by single-molecule fluorescence spectroscopy  

Microsoft Academic Search

The interfacial electron transfer processes between a fluorescent water-soluble perylene diimide dye (WS-PDI) and TiO2 nanoparticles were investigated using single-molecule fluorescence spectroscopy. Based on the single-molecule fluorescence spectral measurements, it was suggested that the local environment and\\/or the structural conformation of single WS-PDI molecules play important roles in the efficiency of the electron injection from WS-PDI in the singlet excited

Takashi Tachikawa; Shi-Cong Cui; Sachiko Tojo; Mamoru Fujitsuka; Tetsuro Majima

2007-01-01

285

Addition of alpha-tocopherol to culture medium improves the quality and cryosurvival of nuclear-transferred ovine embryos.  

PubMed

The aim of this study was to reconstruct and cryopreserve somatic cell nuclear transferred (SCNT) ovine embryos and evaluate the effect of alpha-tocopherol on blastocyst development and subsequent cryosurvival of the SCNT embryos. The alpha-tocopherol (100 microg/ml) was added into culture medium for the SCNT embryos, the yield and total cell numbers of blastocysts were determined and the apoptosis incidences of the blastocysts were evaluated using the TUNEL assay. The blastocysts from the alpha-tocopherol and untreated groups were then frozen-thawed, and their cryosurvival was assessed by in vitro culture for 48 h. The results showed that there were no significant differences in blastocyst yield (26.3 vs. 22.3%) and total cell number (68.2 vs. 64.3) between the alpha-tocopherol and untreated groups. However, addition of alpha-tocopherol to the culture medium significantly decreased the apoptotic cell number (3.4 vs. 5.5) and significantly increased the cryosurvival of SCNT blastocysts (66.8 vs. 50.7%). In conclusion, addition of alpha-tocopherol to SCNT embryo culture medium was beneficial for improving embryo quality by decreasing the apoptotic blastocyst cell number and improving the tolerance of the embryos to cryopreservation. PMID:18580043

Peng, Xin-Rong; Liu, Tao; Zhang, Yong

2008-06-26

286

A Simple Approach for COnsumption and RElease (CORE) Analysis of Metabolic Activity in Single Mammalian Embryos  

PubMed Central

Non-invasive assay of the consumption and release of metabolites by individual human embryos could allow selection at the cleavage stage of development and facilitate Single Embryo Transfer in clinical IVF but will require simple, high throughput, sensitive methods applicable to small volume samples. A rapid, simple, non-invasive method has therefore been devised using a standard fluorescence plate reader, and used to measure the consumption of pyruvate and glucose, and release of lactate by single bovine embryos at all stages of preimplantation development in culture; amino acid profiles have been determined using HPLC. Early embryos with an ‘intermediate’ level (6.14±0.27 pmol/embryo/h) of pyruvate uptake were associated with the highest rate (68.3%) of blastocyst development indicating that a mid “optimum” range of pyruvate consumption correlates with high viability in this bovine model.

Guerif, Fabrice; McKeegan, Paul; Leese, Henry J.; Sturmey, Roger G.

2013-01-01

287

Single-molecule fluorescence resonance energy transfer reveals a dynamic equilibrium between closed and open conformations of syntaxin 1  

PubMed Central

Protein conformational transitions form the molecular basis of many cellular processes, such as signal transduction and membrane traffic. However, in many cases, little is known about their structural dynamics. Here we have used dynamic single-molecule fluorescence to study at high time resolution, conformational transitions of syntaxin 1, a soluble N-ethylmaleimide-sensitive factor attachment protein receptors protein essential for exocytotic membrane fusion. Sets of syntaxin double mutants were randomly labeled with a mix of donor and acceptor dye and their fluorescence resonance energy transfer was measured. For each set, all fluorescence information was recorded simultaneously with high time resolution, providing detailed information on distances and dynamics that were used to create structural models. We found that free syntaxin switches between an inactive closed and an active open configuration with a relaxation time of 0.8 ms, explaining why regulatory proteins are needed to arrest the protein in one conformational state.

Margittai, M.; Widengren, J.; Schweinberger, E.; Schroder, G. F.; Felekyan, S.; Haustein, E.; Konig, M.; Fasshauer, D.; Grubmuller, H.; Jahn, R.; Seidel, C. A. M.

2003-01-01

288

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

289

Xanthones as antioxidants: a theoretical study on the thermodynamics and kinetics of the single electron transfer mechanism.  

PubMed

Mangosteen (Garcinia mangostana) is considered the queen of the tropical fruits. It has a dark red pericarp that is rich in bioactive compounds including xanthones, which have been classified as very good antioxidants from several experimental results. In this work, the antioxidant properties of twenty xanthones isolated from the pericarp of Garcinia mangostana are studied considering the single electron transfer mechanism (SET). According to their most acidic pK(a) value, under physiological conditions the monoanionic form is present in significant amounts. For this reason, eight deprotonated xanthones are also considered in this study. Quantum chemical calculations were performed in order to assess their free radical scavenging capacity in terms of vertical ionization energies and vertical electron affinities. With these two chemical descriptors it is possible to construct a map that allows a straightforward comparison of the electron transfer viability between any pair of reactants. Such a map for the studied xanthones and the free radicals ?OH and O(2)?(-), in aqueous solution, indicates that xanthones can either donate or accept electrons in order to deactivate free radicals. A new relationship between the ionization potential and the electron affinity is proposed to predict the thermochemical viability of the SET processes. The electron transfer reactions between xanthones and ?OH or O(2)?(-) are endergonic and, therefore, thermodynamically unfeasible. However, the reaction of deprotonated xanthones with ?OH is exergonic. Thus, the deprotonated xanthones are more reactive than the neutral species through the SET mechanism. The monoanions of xanthones, which are present under physiological conditions were found to react with ?OH at diffusion-limited rates. PMID:22327405

Martínez, Ana; Hernández-Marin, Elizabeth; Galano, Annia

2012-02-13

290

Pregnancy rates, prenatal and postnatal survival of offspring, and litter sizes after reciprocal embryo transfer in DBA/2JHd, C3H/HeNCrl and NMRI mice.  

PubMed

Success of embryo transfer is often a limiting factor in transgenic procedures and rederivation efforts, and depends on the genetic background of the donor and recipient strains used. Here we show that embryo transfer to DBA/2J females is possible, and present data on pre- and postnatal success rates after reciprocal embryo transfer using the inbred DBA/2J and C3H/HeN, and outbred NMRI strains. The highest embryo yield was achieved in outbred NMRI females, but embryo yields were similar in DBA/2J and C3H/HeN mice following superovulation despite poor estrus cycle synchronization in DBA/2J females. In-strain transfer of DBA/2J blastocysts (transfer of embryos to recipients from the same strain) resulted in pregnancy rates (57.1%) similar to those obtained following in-strain transfer of C3H/HeN (60.0%) and NMRI mice (83.3%), although the prenatal survival rate of blastocysts was low. Moreover, from the pups born only half survived the postnatal period after transfer of DBA/2J and C3H/HeN blastocysts to DBA/2J recipients. These problems were not observed when transferring NMRI-blastocysts to C3H/HeN and DBA/2J mothers. The number of blastocysts transferred also had a positive effect on the success of embryo transfer. In conclusion, C3H/HeN and DBA/2J females can be used as recipients for embryo transfer procedures for certain donor strains like NMRI, as one major determinant seems to be the genetic background of the embryos transferred. We also recommend to increase the number of DBA/2J blastocysts transferred, and to foster the DBA/2J pups to other DBA/2J mothers postnatally for in-strain transfer of DBA/2J mice. PMID:22401828

Rose, C; Schwegler, H; Hanke, J; Yilmazer-Hanke, D M

2012-03-07

291

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

292

Disruption of blastocyst implantation by triclosan in mice: impacts of repeated and acute doses and combination with bisphenol-A.  

PubMed

Triclosan is an antimicrobial additive in many personal care and household products, and evidence indicates that it can be estrogenic. As estrogen elevations can disrupt blastocyst implantation, we examined the influence of triclosan on implantation in inseminated mice. Doses of 18 and 27 mg/animal/day (about 523 and 785 mg/kg/day) on gestational days (GD) 1-3 reduced the number of implantation sites on GD 6. Single doses on GD 2 or 3 also reduced implantation sites. Subsequently, we examined triclosan in combination with bisphenol-A (BPA), which also can disrupt implantation. Although doses of 4 mg BPA (122 mg/kg) and 9 mg triclosan (262 mg/kg) on GD 1-3 were individually ineffective, in combination they reduced the number of implantation sites and also increased gestation length. All of these effects mimicked stronger effects of 17?-estradiol. These data are consistent with potential estrogenic properties of triclosan, and show that it can act together with BPA. PMID:23059059

Crawford, Brent R; Decatanzaro, Denys

2012-10-08

293

Nanoscopic heterogeneities in adsorption and electron transfer processes of perylene diimide dye on TiO 2 nanoparticles studied by single-molecule fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

The interfacial electron transfer processes between a fluorescent water-soluble perylene diimide dye (WS-PDI) and TiO 2 nanoparticles were investigated using single-molecule fluorescence spectroscopy. Based on the single-molecule fluorescence spectral measurements, it was suggested that the local environment and/or the structural conformation of single WS-PDI molecules play important roles in the efficiency of the electron injection from WS-PDI in the singlet excited state to TiO 2. The observed single-molecule fluorescence blinking behavior was interpreted in terms of the interfacial electron-transfer dynamics between the single WS-PDI molecules and TiO 2 nanoparticles.

Tachikawa, Takashi; Cui, Shi-Cong; Tojo, Sachiko; Fujitsuka, Mamoru; Majima, Tetsuro

2007-08-01

294

Theory of the energy transfer efficiency and fluorescence lifetime distribution in single-molecule FRET.  

PubMed

In single-molecule FRET experiments with pulsed lasers, not only the colors of the photons but also the fluorescence lifetimes can be monitored. Although these quantities appear to be random, they are modulated by conformational dynamics. In order to extract information about such dynamics, we develop the theory of the joint distribution of FRET efficiencies and fluorescence lifetimes determined from bins (or bursts) of photons. Our starting point is a rigorous formal expression for the distribution of the numbers of donor and acceptor photons and donor lifetimes in a bin that treats the influence of conformational dynamics on all timescales. This formula leads to an analytic result for a two-state system interconverting on a timescale slower than the interphoton time and to an efficient simulation algorithm for multistate dynamics. The shape of the joint distribution contains more information about conformational dynamics than the FRET efficiency histogram alone. In favorable cases, the connectivity of the underlying conformational states can be determined directly by simple inspection of the projection of the joint distribution on the efficiency-lifetime plane. PMID:22550169

Gopich, Irina V; Szabo, Attila

2012-05-01

295

Post-fusion treatment with MG132 increases transcription factor expression in somatic cell nuclear transfer embryos in pigs.  

PubMed

The objective of this study was to examine the effect of post-fusion treatment of somatic cell nuclear transfer (SCNT) oocytes with the proteasomal inhibitor MG132 on maturation promoting factor (MPF) activity, nuclear remodeling, embryonic development, and gene expression of cloned pig embryos. Immediately after electrofusion, SCNT oocytes were treated with MG132 and/or caffeine for 2 hr, vanadate for 0.5 hr, or vanadate for 0.5 hr followed by MG132 for 1.5 hr. Of the MG132 concentrations tested (0-5 microM), the 1 microM concentration showed a higher rate of blastocyst formation (25.9%) than 0 (14.2%), 0.5 (16.9%), and 5 microM (16.9%). Post-fusion treatment with MG132, caffeine, and both MG132 and caffeine improved blastocyst formation (22.1%, 21.4%, and 24.4%, respectively), whereas vanadate treatment inhibited blastocyst formation (6.5%) compared to the control (11.1%). When examined 2 hr after fusion and 1 hr after activation, MPF activity remained at a higher (P < 0.05) level in SCNT oocytes that were treated post-fusion with caffeine and/or MG132, but it was decreased by vanadate. The rate of oocytes showing premature chromosome condensation was not altered by MG132 but was decreased by vanadate treatment. In addition, formation of single pronuclei was increased by MG132 compared to control and vanadate treatment. MG132-treated embryos showed increased expression of POU5F1, DPPA2, DPPA3, DPPA5, and NDP52l1 genes compared to control embryos. Our results demonstrate that post-fusion treatment of SCNT oocytes with MG132 prevents MPF degradation and increases expression of transcription factors in SCNT embryos, which are necessary for normal development of SCNT embryos. PMID:19813265

You, Jinyoung; Lee, Joohyeong; Kim, Jinyoung; Park, Junhong; Lee, Eunsong

2010-02-01

296

Impact of developmental stage at cryopreservation and transfer on clinical outcome of frozen embryo cycles  

Microsoft Academic Search

Although several early IVF successes were achieved after transferring fully formed blastocysts, the majority of embryos replaced worldwide over the past 30 years have been at the cleavage stage. The programme at this study centre has previously found that delaying an embryo transfer to day 5 can reduce the chance for a high-order multiple gestation without compromising the pregnancy rate

Nicole Noyes; Andrea Reh; Caroline McCaffrey; Orkun Tan; Lewis Krey

2009-01-01

297

Embryonic stem cells generated by nuclear transfer of human somatic nuclei into rabbit oocytes  

Microsoft Academic Search

To solve the problem of immune incompatibility, nuclear transplantation has been envisaged as a means to produce cells or tissues for human autologous transplantation. Here we have derived embryonic stem cells by the transfer of human somatic nuclei into rabbit oocytes. The number of blastocysts that developed from the fused nuclear transfer was comparable among nuclear donors at ages of

Ying CHEN; Zhi Xu HE; Ailian LIU; Kai WANG; Wen Wei MAO; Jian Xin CHU; Yong LU; Zheng Fu FANG; Ying Tang SHI; Qing Zhang YANG; Da Yuan CHEN; Min Kang WANG; Jin Song LI; Shao Liang HUANG; Xiang Yin KONG; Yao Zhou SHI; Zhi Qiang WANG; Jia Hui XIA; Zhi Gao LONG; Zhi Gang XUE; Wen Xiang DING; Hui Zhen SHENG

2003-01-01

298

Nuclear genome transfer in human oocytes eliminates mitochondrial DNA variants.  

PubMed

Mitochondrial DNA mutations transmitted maternally within the oocyte cytoplasm often cause life-threatening disorders. Here we explore the use of nuclear genome transfer between unfertilized oocytes of two donors to prevent the transmission of mitochondrial mutations. Nuclear genome transfer did not reduce developmental efficiency to the blastocyst stage, and genome integrity was maintained provided that spontaneous oocyte activation was avoided through the transfer of incompletely assembled spindle-chromosome complexes. Mitochondrial DNA transferred with the nuclear genome was initially detected at levels below 1%, decreasing in blastocysts and stem-cell lines to undetectable levels, and remained undetectable after passaging for more than one year, clonal expansion, differentiation into neurons, cardiomyocytes or ?-cells, and after cellular reprogramming. Stem cells and differentiated cells had mitochondrial respiratory chain enzyme activities and oxygen consumption rates indistinguishable from controls. These results demonstrate the potential of nuclear genome transfer to prevent the transmission of mitochondrial disorders in humans. PMID:23254936

Paull, Daniel; Emmanuele, Valentina; Weiss, Keren A; Treff, Nathan; Stewart, Latoya; Hua, Haiqing; Zimmer, Matthew; Kahler, David J; Goland, Robin S; Noggle, Scott A; Prosser, Robert; Hirano, Michio; Sauer, Mark V; Egli, Dieter

2012-12-19

299

A numerical analysis of solid-liquid phase change heat transfer around a single and two horizontal, vertically spaced cylinders in a rectangular cavity  

Microsoft Academic Search

In the present study, a new numerical model is proposed to analyze solid-liquid phase change heat transfer in a complicated geometry. The present model can treat the solid\\/liquid phase change heat transfer with\\/without porous media, as well as conventional transient natural convection with\\/without porous media. Solidification calculations of pure water (without porous media) around a single cylinder and two cylinders

R. Viskanta

1997-01-01

300

Pressure-induced rotational energy transfer in H2CO A~ 1A2 v4 = 1: Dipolar M-dependence with no single-collision elastic contribution  

Microsoft Academic Search

We have performed a series of measurements on H2CO A~ 1A2 v4 = 1 single rotational levels using Transient Gain Spectroscopy (TGS), which was designed to provide detailed information on state-to-state population transfer and on the relaxation and transfer of rotational alignment. Measurements of the time dependence of the population of the directly populated JKa,Kc = 10,1 level, and of

Stephen L. Coy; Scott D. Halle; James L. Kinsey; Robert W. Field

1992-01-01

301

Metabolic Induction and Early Responses of Mouse Blastocyst Developmental Programming following Maternal Low Protein Diet Affecting Life-Long Health  

PubMed Central

Previously, we have shown that a maternal low protein diet, fed exclusively during the preimplantation period of mouse development (Emb-LPD), is sufficient to induce by the blastocyst stage a compensatory growth phenotype in late gestation and postnatally, correlating with increased risk of adult onset cardiovascular disease and behavioural dysfunction. Here, we examine mechanisms of induction of maternal Emb-LPD programming and early compensatory responses by the embryo. Emb-LPD induced changes in maternal serum metabolites at the time of blastocyst formation (E3.5), notably reduced insulin and increased glucose, together with reduced levels of free amino acids (AAs) including branched chain AAs leucine, isoleucine and valine. Emb-LPD also caused reduction in the branched chain AAs within uterine fluid at the blastocyst stage. These maternal changes coincided with an altered content of blastocyst AAs and reduced mTORC1 signalling within blastocysts evident in reduced phosphorylation of effector S6 ribosomal protein and its ratio to total S6 protein but no change in effector 4E-BP1 phosphorylated and total pools. These changes were accompanied by increased proliferation of blastocyst trophectoderm and total cells and subsequent increased spreading of trophoblast cells in blastocyst outgrowths. We propose that induction of metabolic programming following Emb-LPD is achieved through mTORC1signalling which acts as a sensor for preimplantation embryos to detect maternal nutrient levels via branched chain AAs and/or insulin availability. Moreover, this induction step associates with changes in extra-embryonic trophectoderm behaviour occurring as early compensatory responses leading to later nutrient recovery.

Eckert, Judith J.; Porter, Richard; Watkins, Adam J.; Burt, Elizabeth; Brooks, Suzanne; Leese, Henry J.; Humpherson, Peter G.; Cameron, Iain T.; Fleming, Tom P.

2012-01-01

302

Trichostatin a improves preimplantation development of bovine cloned embryos and alters expression of epigenetic and pluripotency genes in cloned blastocysts.  

PubMed

We investigated the effects of exposure time and concentration of trichostatin A (TSA) on in vitro development and quality of bovine SCNT embryos. At multiple time points, the relative expression of genes related to pluripotency and reprogramming was analyzed in order to assess the quality of preimplantation embryos cultured in media with TSA using real-time PCR. Development into blastocysts was higher in 100 nM TSA than in controls (35.96 vs. 28.30%, P<0.05). Study of 100 nM TSA exposure time showed development into blastocysts was higher during both short-term and long-term exposure than in controls (36.17 and 34.04 vs. 23.45%), but there was no significant difference between TSA groups. Nanog expression in blastocysts after long-term TSA exposure was similar to that in IVF blastocysts and greater than in controls and short-term exposed embryos. The Oct4 levels in the short-term exposure group were similar to those of IVF blastocysts, while Oct4 expression in long-term exposed embryos was significantly higher than in other groups. Measurement of DNMT1 and HDAC1 in blastocysts showed a similar expression profile among IVF and TSA groups regardless of treatment duration. In conclusion, this study suggests that TSA treatment after SCNT in bovine embryos can improve in vitro development of embryos by increasing the blastocysts formation and positive reprogramming of the reconstructed embryo genome caused by downregulation of DNA methylation and up-regulation of pluripotency. PMID:22785124

Oh, Hyun Ju; Lee, Tae Hee; Lee, Ji Hyun; Lee, Byeong Chun

2012-06-18

303

Heat transfer of lithium single-phase flow and helium–lithium two-phase flow in a circular channel under transverse magnetic field  

Microsoft Academic Search

Characteristics of pressure drop and heat transfer have been investigated for a lithium single-phase flow and a helium-lithium two-phase flow in a horizontal conducting circular channel in the presence of a uniform transverse magnetic field up to 1.4 T as related to the lithium cooling for magnetic-confinement fusion reactors. By the application of the magnetic field to the lithium single-phase

Minoru Takahashi; Naotaka Umeda; Mitsuo Matsuzaki; Akira Inoue; Masanori Aritomi

1998-01-01

304

MicroRNA regulation via DNA methylation during the morula to blastocyst transition in mice.  

PubMed

Epigenetic regulation is responsible for transcriptional silencing of genes and parental imprinting. This study addresses the question whether microRNAs (miRNAs) could be affected by DNA methylation during morula-blastocyst transition. Mouse embryos were treated with/without a DNA methyltransferase inhibitor (5-aza-2'-deoxycytidine, 5-aza-dC, 10 nM-5 ?M). Changes of miRNAs were analyzed by quantitative real-time (Q-PCR)-based megaplex pre-amp microRNA assays. Development from morula to blastocyst in mice was inhibited by 5-aza-dC in a dose-dependent manner (10 nM-5 ?M), with half of the embryos arrested at morula stage when treated with levels of 5-aza-dC as low as 50 nM. In total, 48 down-regulated microRNAs and 17 up-regulated microRNAs (?5-fold changes) were identified after 5-aza-dC treatment, including let-7e, mir-20a, mir-21, mir-34b, mir-128b and mir-452. Their predicted targets were selected based on software analysis, published databases and further confirmed by Q-PCR. At least eight targets, including dnmt3a, jagged 1, sp1, edg2, abcg4, numa1, tmsb10 and csf1r were confirmed. In conclusion, 5-aza-dC-modified microRNA profiles and identification of the microRNA's targets during the morula to blastocyst stage in mice provide information that helps us to explore the relationship between fertility, microRNA regulation and epigenetic intervention. PMID:22053057

Lee, Yee-Ming; Chen, Huei-Wen; Maurya, Pawan Kumar; Su, Ching-Mao; Tzeng, Chii-Ruey

2011-11-03

305

Effect of LiCl on differentiation of mouse embryos beyond the blastocyst stage.  

PubMed

In order to test the effect of Li+ on cell differentiation, 2-cell embryos were cultured in vitro with or without Li+ to the blastocyst stage and then, in a "implantation" culture medium, with or without Li+, up the early egg-cylinder stage. Our results show: 1) that Li+ in the preimplantation medium diminishes "implantation" success significantly; 2) that trophoblastic vesicles, produced by culturing preimplantation embryos with Li+, do not generate an inner cell mass when further cultured in "implantation" medium; 3) that the ultrastructure of "implanted" embryos is similar in all experimental series. PMID:6099098

Fernández, M S; Izquierdo, L

1983-08-01

306

Nuclear magnetic resonance in [N(CH3)4]2CoCl4 single crystals: transferred hyperfine interaction and spin-lattice relaxation rate  

NASA Astrophysics Data System (ADS)

The molecular susceptibility and paramagnetic shift of [N(CH3)4]2CoCl4 single crystals were measured, and from these experimental results we obtained the transferred hyperfine interaction, Hhf, due to the transfer of spin density from Co2+ ions to [N(CH3)4]+ ions. The transferred hyperfine interaction can be expressed as a linear equation, with Hhf increasing with increasing temperature. The remarkable change in Hhf near Tc5 (=192 K) corresponds to a phase transition. The proton spin-lattice relaxation times of [N(CH3)4]2CoCl4 single crystals were also investigated, and it was found that the relaxation process can be described by a single exponential function. The variation of the relaxation time with temperature undergoes a remarkable change near Tc5, confirming the presence of a phase transition at that temperature. From the above results, we conclude that the increase in Hhf with increasing temperature is large enough to allow the transfer of spin density between Co2+ ions and the nuclear spins of the nonmagnetic [N(CH3)4]+ ions in the lattice, and thus the increase in the relaxation time with temperature is attributed to an increase in the transferred hyperfine field.

Lim, Ae Ran

2005-06-01

307

Dynamics and folding of single two-stranded coiled-coil peptides studied by fluorescent energy transfer confocal microscopy  

PubMed Central

We report single-molecule measurements on the folding and unfolding conformational equilibrium distributions and dynamics of a disulfide crosslinked version of the two-stranded coiled coil from GCN4. The peptide has a fluorescent donor and acceptor at the N termini of its two chains and a Cys disulfide near its C terminus. Thus, folding brings the two N termini of the two chains close together, resulting in an enhancement of fluorescent resonant energy transfer. End-to-end distance distributions have thus been characterized under conditions where the peptide is nearly fully folded (0 M urea), unfolded (7.4 M urea), and in dynamic exchange between folded and unfolded states (3.0 M urea). The distributions have been compared for the peptide freely diffusing in solution and deposited onto aminopropyl silanized glass. As the urea concentration is increased, the mean end-to-end distance shifts to longer distances both in free solution and on the modified surface. The widths of these distributions indicate that the molecules are undergoing millisecond conformational fluctuations. Under all three conditions, these fluctuations gave nonexponential correlations on 1- to 100-ms time scale. A component of the correlation decay that was sensitive to the concentration of urea corresponded to that measured by bulk relaxation kinetics. The trajectories provided effective intramolecular diffusion coefficients as a function of the end-to-end distances for the folded and unfolded states. Single-molecule folding studies provide information concerning the distributions of conformational states in the folded, unfolded, and dynamically interconverting states.

Talaga, David S.; Lau, Wai Leung; Roder, Heinrich; Tang, Jianyong; Jia, Yiwei; DeGrado, William F.; Hochstrasser, Robin M.

2000-01-01

308

Bioimaging of geographically adjacent proteins in a single cell by quantum dot-based fluorescent resonance energy transfer.  

PubMed

Thousands of proteins are simultaneously involved in the maintenance of a single cancer cell. Fluorescent resonance energy transfer (FRET) is one of the most general techniques for imaging biologically interacting molecules in a cell. Here, we applied FRET to image the co-localization of two proteins that do not interact biologically (nucleolin and integrin ?(v) ?(3),) both of which are highly expressed in the plasma membrane of cancer cells. AS1411 aptamer, which targets nucleolin, was labeled by Cy3 (Cy3-AS1411) and arginine-glycine-aspartic acid (RGD) peptide, which targets integrin ?(v) ?(3) , was conjugated with quantum dot (525?nm, Qd) Qd arginine-glycine-aspartic acid (Qd-RGD). FRET activities between Cy3-AS1411 and Qd-RGD were measured in HeLa cells, a human cervical cancer cell line. FRET phenomena between Qd and Cy3 showed good compatibility according to proximity. The fluorescence signature using Qd-RGD and Cy3-AS1411 showed that nucleolin and integrin ?(v) ?(3) proteins were highly expressed in HeLa cells. Co-incubation of Qd-RGD and Cy3-AS1411 in a single HeLa cell demonstrated that the fluorescence overlay by FRET was quantitatively and geographically quite different from that of individual confocal images. These results suggest that Qd-based FRET analysis can provide information on geographical co-localization of proteins in naïve cells, which is very important for determining the molecular and cellular functions of genes involved in cancers and other clinical diseases. PMID:21136958

Kang, Won Jun; Ko, Mee Hyang; Lee, Dong Soo; Kim, Soonhag

2009-10-13

309

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.

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

1987-01-01

310

Characteristics of heat transfer and fluid flow in a channel with single-row plates array oblique to flow direction for photovoltaic\\/thermal system  

Microsoft Academic Search

This study has been carried out to investigate the characteristics of convective heat transfer and fluid flow for a single row of oblique plates array to the flow direction inside a channel. The flow inside the channel is laminar and the plates array have spanwise distance between the plates and heated by radiation. This configuration has been designed to be

Ahmed Hamza H. Ali; Mahmoud Ahmed; M. S. Youssef

2010-01-01

311

Cryovoltammetrically probing functional group reductive cleavage: alkyl-sulfur versus aryl-sulfur bond cleavage in an alkyl naphthyl thioether under single electron-transfer is temperature switchable.  

PubMed

A series of single electron-transfer (SET) reactions on a naphthyl thioether have shown that the reductive cleavage mechanism changes at low temperatures and this selectivity is proved using an electrochemical analysis that mimics the SET reaction conditions. PMID:16896475

Paddon, Christopher A; Bhatti, Farrah L; Donohoe, Timothy J; Compton, Richard G

2006-07-10

312

Detection of single-nucleotide polymorphisms based on the formation of an electron-transfer impeding layer on an electrode surface.  

PubMed

An electrochemical biosensor utilizing the electron-transfer impeding (insulating) power of a conducting polymer for label-free genotyping single-nucleotide polymorphisms is proposed. Excellent selectivity and sensitivity are accomplished through the engagement of a nuclease clean-up step and a cumulative signal generation/amplification process, respectively. PMID:23187763

Gao, Zhiqiang; Shen, Wei; Deng, Huimin; Ren, Yuqian

2012-11-27

313

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

Microsoft Academic Search

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

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

2011-01-01

314

Optical fiber spectroelectrochemical device for detection of catechol at press-transferred single-walled carbon nanotubes electrodes.  

PubMed

A new long-optical-pathway spectroelectrochemical cell for absorptometric measurements in the UV-Vis region was developed. This cell consists of two optical fibers brought face to face and fixed on the working electrode support. As a proof of concept, the spectroelectrochemical cell was applied to the determination of catechol using a press-transferred single-walled carbon nanotube film as the working electrode. Voltabsorptometry was demonstrated to be very helpful in understanding the mechanism of catechol oxidation. The experiments showed that the main oxidation product is o-benzoquinone, but other soluble side products are also observed. Multivariate calibration explains the selection of 390 nm as the best wavelength for the univariate absorptometric determination of catechol, avoiding the interference of oxidation side products. Catechol was quantified using both the electrochemical and the spectroscopic signal, demonstrating that this hybrid technique is an autovalidated analytical method. Dual detection of catechol was also carried out using amperometric spectroelectrochemistry. Finally, spectroelectrochemistry was used to quantify catechol in the presence of hydroquinone. PMID:23407809

Garoz-Ruiz, Jesus; Izquierdo, Daniel; Colina, Alvaro; Palmero, Susana; Heras, Aranzazu

2013-02-14

315

Single pulse excimer laser nanostructuring of thin silicon films: Nanosharp cones formation and a heat transfer problem  

SciTech Connect

We present analytical and computer modeling along with an experiment on the formation of sharp conical tips on monocrystalline silicon thin films, silicon-on-insulator, subjected to irradiation by single 25 ns pulses from a KrF excimer laser focused into a spot several micrometers in diameter. These fabricated structures have heights of about 1 {mu}m and apical radii of curvature of several tens of nanometers. We offer a simplified analytical model for the formation of these structures. The computer simulation includes two-dimensional time-dependant heat transfer and phase transformations in Si films on SiO{sub 2} substrates that result from the laser irradiation (the Stefan problem). It is shown that upon irradiation and initial melting, the liquid/solid interface remains mainly parallel to the surface of the film. After the laser pulse, the molten material self-cools and resolidifies. The solid/liquid interface moves predominately laterally toward the center of the irradiated spot, forming an almost vertical front. We discuss the relation between the dynamics of the melting/freezing front movement and the displacement of material in the irradiated spot.

Eizenkop, Julia; Avrutsky, Ivan; Auner, Gregory; Georgiev, Daniel G.; Chaudhary, Vipin [Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202 (United States); Department of Electrical Engineering and Computer Science, University of Toledo, Toledo, Ohio 43606-3390 (United States); Department of Computer Science and Engineering, The State University of New York, Buffalo, New York 14260 (United States)

2007-05-01

316

Single half-wavelength ultrasonic particle filter: predictions of the transfer matrix multilayer resonator model and experimental filtration results.  

PubMed

The quantitative performance of a "single half-wavelength" acoustic resonator operated at frequencies around 3 MHz as a continuous flow microparticle filter has been investigated. Standing wave acoustic radiation pressure on suspended particles (5-microm latex) drives them towards the center of the half-wavelength separation channel. Clarified suspending phase from the region closest to the filter wall is drawn away through a downstream outlet. The filtration efficiency of the device was established from continuous turbidity measurements at the filter outlet. The frequency dependence of the acoustic energy density in the aqueous particle suspension layer of the filter system was obtained by application of the transfer matrix model [H. Nowotny and E. Benes, J. Acoust. Soc. Am. 82, 513-521 (1987)]. Both the measured clearances and the calculated energy density distributions showed a maximum at the fundamental of the piezoceramic transducer and a second, significantly larger, maximum at another system's resonance not coinciding with any of the transducer or empty chamber resonances. The calculated frequency of this principal energy density maximum was in excellent agreement with the optimal clearance frequency for the four tested channel widths. The high-resolution measurements of filter performance provide, for the first time, direct verification of the matrix model predictions of the frequency dependence of acoustic energy density in the water layer. PMID:11931302

Hawkes, Jeremy J; Coakley, W Terence; Gröschl, Martin; Benes, Ewald; Armstrong, Sian; Tasker, Paul J; Nowotny, Helmut

2002-03-01

317

Transferred hyperfine field of Rb2CoCl4 single crystals in the ferroelectric incommensurate normal phase by 87Rb NMR  

NASA Astrophysics Data System (ADS)

The molecular susceptibility and paramagnetic shift of Rb2CoCl4 single crystals grown using the slow evaporation method were measured, and from these experimental results we obtained the transferred hyperfine interaction due to the transfer of spin density from Co2+ ions to Rb+ ions. The transferred hyperfine field was obtained for the ferroelectric, incommensurate, and normal phases. In the case of Rb(I), the transferred hyperfine interaction decreases with increasing temperature in the incommensurate phase, and increases with increasing temperature in the normal phase. The value of Hhf in the incommensurate and normal phases increases abruptly with increasing temperature in the case of Rb(II). These results indicate that the effects due to the transfer of spin density from Co2+ ions to the Rb(I) and Rb(II) ions are large above Ti. In particular, the effect due to the transfer of spin density to Rb(II) ions in the normal phase is very large; the variations with temperature of the transferred hyperfine interactions of the Rb(I) and Rb(II) nuclei are more or less continuous in Tc1 and Ti, and are not affected by the ferroelectric incommensurate normal phase transitions.

Lim, Ae Ran; Bong, Pill Hoon; Jeong, Se-Young

2006-04-01

318

Thermally Processed High-Mobility MOS Thin-Film Transistors on Transferable Single-Crystal Elastically Strain-Sharing Si/SiGe/Si Nanomembranes  

SciTech Connect

Demonstration of high-performance MOS thin-film transistors (TFTs) on elastically strain-sharing single-crystal Si/SiGe/Si nanomembranes (SiNMs) that are transferred to foreign substrates is reported. The transferable SiNMs are realized by first growing pseudomorphic SiGe and Si layers on silicon-on-insulator (SOI) substrates, and then, selectively removing the buried oxide (BOX) layer from the SOI. Before the release, only the SiGe layer is compressively strained. Upon release, part of the compressive strain in the SiGe layer is transferred to the thin Si layers, and the Si layers, thus, become tensile strained. Both the initial compressive strain state in the SiGe layer and the final strain sharing state between the SiGe and the Si layers are verified with X-ray diffraction measurements. The TFTs are fabricated employing the conventional high-temperature MOS process on the strain-shared SiNMs that are transferred to an oxidized Si substrate. The transferred strained-sharing SiNMs show outstanding thermal stability and can withstand the high-temperature TFT process on the new host substrate. The strained-channel TFTs fabricated on the new host substrate show high current drive capability and an average electron effective mobility of 270 cm{sup 2}/V ldr s. The results suggest that transferable and thermally stable single-crystal elastically strain- sharing SiNMs can serve as excellent active material for high-speed device application with a simple and scalable transfer method. The demonstration of MOS TFTs on the transferable nanomembranes may create the opportunity for future high-speed Si CMOS heterogeneous integration on any substrate.

Yuan, H.-C.; Kelly, M. M.; Savage, D. E.; Lagally, M. G.; Celler, G. K.; Zhenqiang, M.

2008-03-01

319

Effect of estrous cow serum during bovine embryo culture on blastocyst development and cryotolerance after slow freezing or vitrification.  

PubMed

The present study investigated the effect of estrous cow serum (ECS) during culture of bovine embryos on blastocyst development and survival after cryopreservation by slow freezing or vitrification. Embryos were derived from in vitro maturation (IVM) and in vitro fertilization (IVF) of abbatoir-derived oocytes. At Day 3, embryos were cultured in three different media: Charles Ronsenkrans medium + amino acids (CR1aa; without bovine serum albumin (BSA)) + 5% estrous cow serum (CR1-ECS), CR1aa + 3 mg/mL BSA (CR1-BSA) or CR1aa + 5% ECS + 3 mg/mL BSA (CR1-ECS-BSA). At 7.5 d post-insemination (PI), blastocyst yield and quality were evaluated; blastocysts and expanded blastocysts from each media were cryopreserved by Open Pulled Straw (OPS) vitrification method or slow freezing (1.5 M ethylene glycol, EM). Total blastocyst yield did not differ among CR1-ECS, CR1-BSA and CR1-ECS-BSA (30.9, 33.1 and 32.9%, respectively, P < 0.05). Embryo survival (hatching rate) was higher in vitrified versus slow-frozen embryos (43% versus 12%, respectively, P < 0.01), and in embryos cultured in CR1-BSA (40.3%) compared with those cultured in serum-containing media (CR1-ECS, 21.5% and CR1-ECS-BSA, 19.8%; P < 0.01). In conclusion: (a) it was possible to produce in vitro bovine embryos in serum-free culture medium without affecting blastocyst yield and quality; (b) serum-free medium produced the best quality embryos (in terms of post-cryopreservation survival); and (c) vitrification yielded the highest post-cryopreservation survival rates, regardless of the presence of serum in the culture medium. PMID:16229883

Mucci, N; Aller, J; Kaiser, G G; Hozbor, F; Cabodevila, J; Alberio, R H

2005-10-17

320

Effects of subcutaneous administration of daidzein on blastocyst implantation in rats.  

PubMed

The study was conducted to investigate the effects of phytoestrogen daidzein on blastocyst implantation in rats. Following successful mating, female rats were given daidzein by subcutaneous administration at the dose of 0 (vehicle control, n=15), 50 mg/kg body weight (n=15) and 150 mg/kg body weight (n=15) daily on day 1-7 of pregnancy and were sacrificed on day 8 of gestation. The results revealed that high-dose treatment (150 mg/kg body weight) significantly diminished the rate of blastocyst implantation and serum levels of gonadotropin-releasing hormone (GnRH), progesterone, and gonadotropins (FSH and LH), meanwhile the serum level of beta endorphin increased significantly. These effects were not observed in the low-dose treatment group (50 mg/kg body weight). The results of this study suggested that the anti-implantation effects of daidzein are probably caused by the interference of the hypothalamus-pituitary-gonadal axis which is involved in the implantation process. PMID:15582209

Wu, Zhenlong; Yang, Ying; Chen, Yue; Xia, Guoliang; Zhang, Rongqing

2005-01-01

321

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.

Naturil-Alfonso, Carmen; Saenz-de-Juano, Maria dels Desamparats; Penaranda, David S.

2012-01-01

322

Active cell movements coupled to positional induction are involved in lineage segregation in the mouse blastocyst  

PubMed Central

In the mouse blastocyst, some cells of the inner cell mass (ICM) develop into primitive endoderm (PE) at the surface, while deeper cells form the epiblast. It remained unclear whether the position of cells determines their fate, such that gene expression is adjusted to cell position, or if cells are pre-specified at random positions and then sort. We have tracked and characterised dynamics of all ICM cells from the early to late blastocyst stage. Time-lapse microscopy in H2B-EGFP embryos shows that a large proportion of ICM cells change position between the surface and deeper compartments. Most of this cell movement depends on actin and is associated with cell protrusions. We also find that while most cells are precursors for only one lineage, some give rise to both, indicating that lineage segregation is not complete in the early ICM. Finally, changing the expression levels of the PE marker Gata6 reveals that it is required in surface cells but not sufficient for the re-positioning of deeper cells. We provide evidence that Wnt9A, known to be expressed in the surface ICM, facilitates re-positioning of Gata6-expressing cells. Combining these experimental results with computer modelling suggests that PE formation involves both cell sorting movements and position-dependent induction.

Meilhac, Sigolene M.; Adams, Richard J.; Morris, Samantha A.; Danckaert, Anne; Le Garrec, Jean-Francois; Zernicka-Goetz, Magdalena

2012-01-01

323

Resveratrol protects against methylglyoxal-induced apoptosis and disruption of embryonic development in mouse blastocysts.  

PubMed

Methylglyoxal (MG) is a glucose metabolite. Diabetic patients have increased serum levels of MG, and MG is also implicated in tissue injury during embryonic development. In the present work, we show that MG induces apoptosis in the inner cell mass of mouse blastocysts and inhibits cell proliferation. Both effects are suppressed by resveratrol, a grape-derived phytoalexin with known antioxidant and anti-inflammatory properties. MG-treated blastocysts displayed lower levels of implantation (compared to controls) when plated on culture dishes in vitro and a reduced ability to proceed to later stages of embryonic development. Pretreatment with resveratrol prevented MG-induced disruption of embryonic development, both in vitro and in vivo. Further investigation of these processes revealed that MG directly promotes reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (MMP), and activation of caspase-3, whereas resveratrol effectively blocks MG-induced ROS production and the accompanying apoptotic biochemical changes. Our results collectively imply that MG triggers the mitochondrion-dependent apoptotic pathway via ROS generation, and the antioxidant activity of resveratrol prevents MG-induced toxicity. PMID:21793156

Huang, Fu-Jen; Chin, Ting-Yu; Chan, Wen-Hsiung

2011-07-26

324

Transcriptome profiling of rabbit parthenogenetic blastocysts developed under in vivo conditions.  

PubMed

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; Vicente, José S; Marco-Jiménez, Francisco

2012-12-12

325

Silencing or amplification of endocannabinoid signaling in blastocysts via CB1 compromises trophoblast cell migration.  

PubMed

Endocannabinoid signaling plays key roles in multiple female reproductive events. Previous studies have shown an interesting phenomenon, that mice with either silenced or elevated endocannabinoid signaling via Cnr1 encoding CB(1) show similar defects in several pregnancy events, including preimplantation embryo development. To unravel the downstream signaling of this phenomenon, microarray studies were performed using RNAs collected from WT, Cnr1(-/-), and Faah(-/-) mouse blastocysts on day 4 of pregnancy. The results indicate that about 100 genes show unidirectional changes under either silenced or elevated anandamide signaling via CB(1). Functional enrichment analysis of the microarray data predicted that multiple biological functions and pathways are affected under aberrant endocannabinoid signaling. Among them, genes enriched in cell migration are suppressed in Cnr1(-/-) or Faah(-/-) blastocysts. Cell migration assays validated the prediction of functional enrichment analysis that cell mobility and spreading of either Cnr1(-/-) or Faah(-/-) trophoblast stem cells are compromised. Either silenced or elevated endocannabinoid signaling via CB(1) causes similar changes in downstream targets in preimplantation embryos and trophoblast stem cells. This study provides evidence that a tightly regulated endocannabinoid signaling is critical to normal preimplantation embryo development and migration of trophoblast stem cells. PMID:22833670

Xie, Huirong; Sun, Xiaofei; Piao, Yulan; Jegga, Anil G; Handwerger, Stuart; Ko, Minoru S H; Dey, Sudhansu K

2012-07-24

326

Silencing or Amplification of Endocannabinoid Signaling in Blastocysts via CB1 Compromises Trophoblast Cell Migration*  

PubMed Central

Endocannabinoid signaling plays key roles in multiple female reproductive events. Previous studies have shown an interesting phenomenon, that mice with either silenced or elevated endocannabinoid signaling via Cnr1 encoding CB1 show similar defects in several pregnancy events, including preimplantation embryo development. To unravel the downstream signaling of this phenomenon, microarray studies were performed using RNAs collected from WT, Cnr1?/?, and Faah?/? mouse blastocysts on day 4 of pregnancy. The results indicate that about 100 genes show unidirectional changes under either silenced or elevated anandamide signaling via CB1. Functional enrichment analysis of the microarray data predicted that multiple biological functions and pathways are affected under aberrant endocannabinoid signaling. Among them, genes enriched in cell migration are suppressed in Cnr1?/? or Faah?/? blastocysts. Cell migration assays validated the prediction of functional enrichment analysis that cell mobility and spreading of either Cnr1?/? or Faah?/? trophoblast stem cells are compromised. Either silenced or elevated endocannabinoid signaling via CB1 causes similar changes in downstream targets in preimplantation embryos and trophoblast stem cells. This study provides evidence that a tightly regulated endocannabinoid signaling is critical to normal preimplantation embryo development and migration of trophoblast stem cells.

Xie, Huirong; Sun, Xiaofei; Piao, Yulan; Jegga, Anil G.; Handwerger, Stuart; Ko, Minoru S. H.; Dey, Sudhansu K.

2012-01-01

327

ATOMIC AND MOLECULAR PHYSICS: Single atoms transferring between a magneto-optical trap and a far-off-resonance optical dipole trap  

NASA Astrophysics Data System (ADS)

Based on our work on single cesium atoms trapped in a large-magnetic-gradient vapour-cell magneto-optical trap (MOT), the signal-to-noise ratio (SNR) is remarkably improved. Also a far-off-resonance optical dipole trap (FORT) formed by a strongly-focused 1064 nm single frequency Nd:YVO4 laser beam is introduced. One cesium atom is prepared in the MOT, and then it can transfer successfully between the MOT and the FORT which is overlapped with the MOT. Utilizing the effective transfer, the lifetime of single atoms trapped in the FORT is measured to be 6.9 ± 0.3 s. Thus we provide a system where the atomic qubit can be coherently manipulated.

He, Jun; Wang, Jing; Yang, Bao-Dong; Zhang, Tian-Cai; Wang, Jun-Min

2009-08-01

328

Derivation of buffalo embryonic stem-like cells from in vitro-produced blastocysts on homologous and heterologous feeder cells  

Microsoft Academic Search

Purpose  The aim of the present study is to compare the ability of homologous and heterologous embryonic fibroblast feeder layers to\\u000a support isolation and proliferation of buffalo ES-like cells generated from hatched and expanded blastocysts produced by in\\u000a vitro fertilization and characterization of derived cells through expression of pluripotent markers.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Embryonic stem cells were derived from hatched and expanded blastocysts through

Dharmendra Kumar; T. Anand; K. P. Singh; M. K. Singh; R. A. Shah; M. S. Chauhan; P. Palta; S. K. Singla; R. S. Manik

329

The Role of Data Transfer on the Selection of a Single vs Multiple Mesh Architecture for Tightly Coupled Multiphysics Applications  

SciTech Connect

Data transfer from one distinct mesh to another may be necessary in any number of applications, including prolongation operations supporting multigrid solution methods, spatial adaptation, remeshing, and arbitrary Lagrangian-Eulerian (ALE) and multiphysics simulation. This data transfer process is also referred to as remapping, rezoning and interpolation. Intermesh data transfer has the potential to introduce error into a simulation; the magnitude and importance of which depends on the transfer scenario and the algorithm used to perform the transfer. For a transient analysis, data transfer may occur many times during a simulation, with possible error accumulation at each transfer. The present study develops selected scenarios that illustrate data transfer error and how it might impact an analysis. This study examines remapping error by using static analytical functions to compare various remapping schemes. It also investigates the significance and nature of data transfer error for a simple multiphysics system involving a transient coupled system of partial differential equations. It concludes that remapping error can be significant both for static functions and for coupled multiphysics systems. Aggregate error is shown to be a function of remapping scheme, mesh coarseness, nature of the remapped function and mesh disparity. In cases of extreme mesh disparity, this study shows that remapping can lead to excessive error and even to solution instability. Further, this work motivates that remapping error should be included in the estimation of numerical error, if data transfer is employed in a numerical simulation.

Richard W. Johnson; Glen A. Hansen; Christopher K Newman

2011-07-01

330

Influence of Transforming Growth Factor-? on Expression of Matrix Metalloproteinase-2, Matrix Metalloproteinase-9, and Epidermal Growth Factor Receptor Gene in the Mouse Blastocysts  

Microsoft Academic Search

Purpose: This study was carried out to investigate the influence of transforming growth factor-a (TGF-a) on the expression of mRNA for matrix metalloproteinase-2 (MMP-2), MMP-9, and epidermal growth factor receptor (EGFR) in mouse blastocysts and the effect on the production and activation of MMP-2 and MMP- 9 during blastocyst outgrowth.

Jeong Hee Kim; Seok Ho Hong; Hee Young Nah; Ji Yun Lee; Hee Dong Chae; Chung Hoon Kim; Byung Moon Kang; In Ha Bae

2002-01-01

331

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

2012-03-01

332

Measurement of the Mass Transfer into Single Drops in the System of Water/Supercritical Carbon Dioxide.  

PubMed

This paper presents a new method for the measurement of mass transfer in isolated water drops. The transport of a component in the water drop can be detected by a change in electrical conductivity. Measurements were performed using a new type of sensor design. In particular the transfer of CO(2) from a continuous fluid phase into the water drop was investigated. CO(2) leads to an increased conductivity in water because of the carbonic acid equilibrium. Experimental conditions ranged from 298 to 323 K in temperature and from 2.5 up to 30.7 MPa in pressure. The mass transfer coefficients obtained give insight into the transfer process and its physical mechanisms. Increasing temperature and density of the surrounding carbon dioxide lead to faster mass transfer processes. The effects of drop geometry and internal turbulences on the mass transfer velocity are discussed. Copyright 2000 Academic Press. PMID:11082241

Zappe; Wesch; Ebert

2000-11-01

333

High-frequency phage-mediated gene transfer in freshwater environments determined at single-cell level  

Microsoft Academic Search

Lateral gene transfer by phages has contributed significantly to the genetic diversity of bacteria. To accurately determine the frequency and range of phage-mediated gene transfer, it is important to understand the movement of DNA among microbes. Using an in situ DNA amplification technique (cycling primed in situ amplification-fluorescent in situ hybridization; CPRINS-FISH), we examined the propensity for phage-mediated gene transfer

Takehiko Kenzaka; Katsuji Tani; Masao Nasu

2010-01-01

334

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

335

Conserved molecular portraits of bovine and human blastocysts as a consequence of the transition from maternal to embryonic control of gene expression.  

PubMed

The present study investigated mRNA expression profiles of bovine oocytes and blastocysts by using a cross-species hybridization approach employing an array consisting of 15,529 human cDNAs as probe, thus enabling the identification of conserved genes during human and bovine preimplantation development. Our analysis revealed 419 genes that were expressed in both oocytes and blastocysts. The expression of 1,324 genes was detected exclusively in the blastocyst, in contrast to 164 in the oocyte including a significant number of novel genes. Genes indicative for transcriptional and translational control (ELAVL4, TACC3) were overexpressed in the oocyte, whereas cellular trafficking (SLC2A14, SLC1A3), proteasome (PSMA1, PSMB3), cell cycle (BUB3, CCNE1, GSPT1), and protein modification and turnover (TNK1, UBE3A) genes were found to be overexpressed in blastocysts. Transcripts implicated in chromatin remodeling were found in both oocytes (NASP, SMARCA2) and blastocysts (H2AFY, HDAC7A). The trophectodermal markers PSG2 and KRT18 were enriched 5- and 50-fold in the blastocyst. Pathway analysis revealed differential expression of genes involved in 107 distinct signaling and metabolic pathways. For example, phosphatidylinositol signaling and gluconeogenesis were prominent pathways identified in the blastocyst. Expression patterns in bovine and human blastocysts were to a large extent identical. This analysis compared the transcriptomes of bovine oocytes and blastocysts and provides a solid foundation for future studies on the first major differentiation events in blastocysts and identification of a set of markers indicative for regular mammalian development. PMID:17595343

Adjaye, James; Herwig, Ralf; Brink, Thore C; Herrmann, Doris; Greber, Boris; Sudheer, Smita; Groth, Detlef; Carnwath, Joseph W; Lehrach, Hans; Niemann, Heiner

2007-06-26

336

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

337

Dynamic expression of Lrp2 pathway members reveals progressive epithelial differentiation of primitive endoderm in mouse blastocyst  

Microsoft Academic Search

Mesenchyme to epithelium transitions are crucial to embryonic development. The early mouse embryo offers an excellent model to study epithelium formation as during the first three days of development two epithelia are formed, the trophectoderm (TE) and the primitive endoderm (PrE). We have previously shown that PrE cells are determined within the blastocyst ICM long before epithelium formation. In this

François Gerbe; Brian Cox; Janet Rossant; Claire Chazaud

2008-01-01

338

Histone modifications and mRNA expression in the inner cell mass and trophectoderm of bovine blastocysts.  

PubMed

Normal development depends on the precise sequence of changes in the configuration of chromatin; these are primarily related to specific biochemical modifications such as acetylation or methylation of histones and DNA methylation. While the role of DNA methylation during preimplantation development has been studied extensively, little is known about histone modifications related to early embryonic development. Here, we investigated gene-specific histone modifications in in vitro produced bovine blastocysts. Selected genes thought to be critical for bovine preimplantation development were examined and included POU5F1 (OCT4), NANOG, INFT, GAPDH, SLC2A3 and IGF1. We used chromatin immunoprecipitation from pools of bovine blastocysts to unravel several modifications of histone H3 in relation to mRNA expression profiles. We focused on the two cell compartments of the blastocyst, the inner cell mass (ICM) and the trophectoderm (TE). We show that gene expression patterns in the ICM and TE of the bovine blastocyst are consistent with histone modification patterns on the promoter of the corresponding genes. The data show a complex epigenetic pattern of promoter occupancy by transcriptionally permissive and repressive H3 modifications. These results pave the way to in-depth epigenetic studies of preimplantation embryos that are crucial to gain a better understanding of the epigenetic changes frequently observed after use of assisted reproductive technologies. PMID:23406883

Herrmann, Doris; Dahl, John Arne; Lucas-Hahn, Andrea; Collas, Philippe; Niemann, Heiner

2013-02-13

339

Successful transfer of the embryos of Przewalski's horses (Equus przewalskii) and Grant's zebra (E. burchelli) to domestic mares (E. caballus)  

Microsoft Academic Search

Summary. Blastocysts were collected non-surgically from 2 Przewalski's horse and 2 Grant's zebra mares and transferred extra-specifically to domestic horse and donkey recipients. Nine Przewalski's horse embryos were transferred surgically, and 2 non- surgically, to domestic Welsh-type pony mares. After surgical transfer, 7 (77\\\\m=.\\\\8%) pregnancies were established and 4 foals were born. Twelve Grant's zebra embryos were transferred surgically to

P. M. Summers; A. M. Shephard; J. K. Hodges; J. Kydd; M. S. Boyle; W. R. Allen

1987-01-01

340

Kinetic energy release in thermal ion-molecule reactions: Single charge-transfer reactions of V sup 2+ and Ta sup 2+ with benzene  

SciTech Connect

Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) has been used to study the single charge-transfer reactions of V{sup 2+} and Ta{sup 2+} with benzene under thermal conditions. Thermal charge-transfer rate constants of 2.0 {times} 10{sup {minus}9} and 1.2 {times} 10{sup {minus}9} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1} were measured for V{sup 2+} and Ta{sup 2+}, respectively. The total kinetic energy of the product ions was determined to be 1.91 {plus minus} 0.50 eV for the V{sup 2+} case and 2.82 {plus minus} 0.50 eV for the Ta{sup 2+} case. These results and a previous study of the Nb{sup 2+}-benzene single charge-transfer system suggest a simple long-distance electron-transfer mechanism proceeding by ionization of the 1a{sub 2u} orbital of benzene with significant internal excitation of the nascent C{sub 6}H{sub 6}{sup +} product.

Gord, J.R.; Freiser, B.S (Purdue Univ., West Lafayette, IN (United States)); Buckner, S.W. (Univ. of Arizona, Tucson (United States))

1991-10-17

341

Mass transfer process analysis near phase boundary with combined PIV-PLIF method, a single-camera single-laser approach  

Microsoft Academic Search

A detailed characterization of interfacial mass transfer phenomena is of great importance in providing further insight into the fundamental physics of interfacial dynamics, and in developing improved engineering models for various environmental and industrial applications. Despite extensive efforts of experimental and theoretical investigations, there remain several fundamental issues yet to be clarified, mainly due to the lack of detailed dynamical

Yong Yuan

2007-01-01

342

Treatment outcome in women with a single ovary versus patients with two ovaries undergoing in vitro fertilization and embryo transfer (IVF\\/ET)  

Microsoft Academic Search

Objective: To compare ovarian response and pregnancy rate between women with one and two ovaries undergoing in vitro fertilization and embryo transfer (IVF\\/ET). Study design: 20 IVF\\/ET treatment cycles in ten women with a single ovary were compared with 60 IVF\\/ET cycles in 47 women with two ovaries. Both groups were matched for age and treated for mechanical infertility. In

E. Levitas; B. Furman; I. Shoham-Vardi; E. Lunenfeld

2000-01-01

343

Forced convection heat transfer to a single and two-phase steam\\/water mixture in a helical coil with radiant heating  

Microsoft Academic Search

The purpose of this study was to perform an analytical and experimental investigation into the heat transfer characteristics for a once-through steam generator with a helical flow geometry. The application is the receiver for a fixed hemispherical mirror solar concentrator on the Crosbyton Solar Power Project. The working fluid, water, goes successively through the single-phase liquid, two-phase and super-heated vapor

Vafaie

1981-01-01

344

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

Microsoft Academic Search

This paper investigates the heat transfer characteristics from thin strips pin fins due to their exposure to a single circular\\u000a downward air jet impingement. Five aluminum specimens were considered; each one has a rectangular base of 84 mm × 78 mm and\\u000a it has an array of about 300 thin strips pin fins. A test rig consists mainly of air compressor; nozzle and protractor

Eldesouki I. EidAbdalla; Abdalla G. Gomaa; Mohamed E. Gomaa

2011-01-01

345

Maternal obesity promotes a proinflammatory signature in rat uterus and blastocyst.  

PubMed

Maternal obesity at conception increases the risk of offspring obesity, thus propagating an intergenerational vicious cycle. Male offspring born to obese dams are hyperresponsive to high fat-diets, gaining greater body weight, fat mass, and additional metabolic sequelae compared to lean controls. In this report, we identify the impact of maternal obesity before conception, on the embryo, and intrauterine milieu during the periimplantation period. We conducted global transcriptomic profiling in the uterus and periimplantation blastocyst, gene/protein expression analyses of inflammatory pathways in conjunction with endocrine and metabolic characterization in the dams at implantation. Uterine gene expression profiles of lean and obese dams revealed distinct signatures for genes regulating inflammation and lipid metabolism. Both pathway and gene-set enrichment analysis revealed uterine nuclear factor-?B and c-Jun N-terminal kinase signaling to be up-regulated in the uterus of obese dams, which was confirmed via immunoblotting. Obese uteri also evidenced an inflammatory secretome with higher chemokine mRNA abundance (CCL2, CCL5, CCL7, and CxCL10) and related regulators (TLR2, CD14, and Ccr1). Increased inflammation in the uterus was associated with ectopic lipid accumulation and expression of lipid metabolic genes. Gene expression in sex-identified male periimplantation blastocyst at day postcoitum 4.5 was clearly influenced by maternal obesity (359 transcripts, ±1.4-fold), including changes in developmental and epigenetic regulators. Akin to the uterus, nuclear factor-?B-regulated proinflammatory genes (CCL4 and CCL5) increased and expression of antioxidant (GPx3) and mitochondrial (TFAM and NRF1) genes decreased in the obese embryos. Our results suggest that ectopic lipid and inflammation may link maternal obesity to increased predisposition of offspring to obesity later in life. PMID:21862610

Shankar, Kartik; Zhong, Ying; Kang, Ping; Lau, Franchesca; Blackburn, Michael L; Chen, Jin-Ran; Borengasser, Sarah J; Ronis, Martin J J; Badger, Thomas M

2011-08-23

346

Heat Transfer from a Single Tube to the Flowing Gas-Solid Suspension in a CFB Riser  

Microsoft Academic Search

The first published studies concerning heat transfer between flowing gas-solid suspensions (pneumatic conveying) and pipe walls appeared in the literature in the early 1960s. More recently, experimental investigations have been extended to circulating fluidized beds. Despite the relatively large number of studies undertaken, mostly in CFB-risers of limited dimensions, the variation of the CFB heat transfer coefficient with operating gas

K. Everaert; J. Baeyens; K. Smolders

2006-01-01

347

Rapid Movement of Water and Cryoprotectants in Pig Expanded Blastocysts via Channel Processes: Its Relevance to Their Higher Tolerance to Cryopreservation.  

PubMed

Pig oocytes and embryos are highly sensitive to cryopreservation; however, tolerance to cryopreservation increases in embryos at the expanded blastocyst stage. This increased tolerance may be attributed to a decrease in cytoplasmic lipid droplets at this stage. We previously showed that an increase in the permeability of the plasma membrane in mouse oocytes to water and cryoprotectants, caused by the artificial expression of aquaporin 3, an aquaglyceroporin, enhanced tolerance to cryopreservation. In the present study, we investigated whether membrane permeability was also involved in the tolerance of pig embryos to cryopreservation. The permeability of oocytes and morulae to water and glycerol was low, whereas that of expanded blastocysts was high. Activation energy for permeability to water, glycerol, ethylene glycol, and dimethyl sulfoxide was markedly lower for expanded blastocysts than for oocytes. This suggests that water and these cryoprotectants move through expanded blastocysts predominantly by facilitated diffusion and through oocytes predominantly by simple diffusion. Aquaporin 3 mRNA was expressed in expanded blastocysts abundantly, but less so in oocytes. On the other hand, the permeability of expanded blastocysts to propylene glycol was as low as that of oocytes, and activation energy for its permeability was similar to that of oocytes, which suggests that propylene glycol moves through oocytes and embryos predominantly by simple diffusion. These results suggest that the higher tolerance of pig expanded blastocysts to cryopreservation is also related to high membrane permeability due to the expression of water/cryoprotectant channels, in addition to the decrease in cytoplasmic lipid droplets. PMID:23966318

Jin, Bo; Higashiyama, Ryu-Ichi; Nakata, Yu-Ichi; Yonezawa, Jun-Ichi; Xu, Shangdan; Miyake, Masashi; Takahashi, Sei-Ichi; Kikuchi, Kazuhiro; Yazawa, Ken-Ichi; Mizobuchi, Shuhei; Niimi, Saori; Kitayama, Mizuho; Koshimoto, Chihiro; Matsukawa, Kazutsugu; Kasai, Magosaburo; Edashige, Keisuke

2013-10-10

348

Adoptive transfer of Mammaglobin-A epitope specific CD8 T cells combined with a single low dose of total body irradiation eradicates breast tumors.  

PubMed

Adoptive T cell therapy has proven to be beneficial in a number of tumor systems by targeting the relevant tumor antigen. The tumor antigen targeted in our model is Mammaglobin-A, expressed by approximately 80% of human breast tumors. Here we evaluated the use of adoptively transferred Mammaglobin-A specific CD8 T cells in combination with low dose irradiation to induce breast tumor rejection and prevent relapse. We show Mammaglobin-A specific CD8 T cells generated by DNA vaccination with all epitopes (Mammaglobin-A2.1, A2.2, A2.4 and A2.6) and full-length DNA in vivo resulted in heterogeneous T cell populations consisting of both effector and central memory CD8 T cell subsets. Adoptive transfer of spleen cells from all Mammaglobin-A2 immunized mice into tumor-bearing SCID/beige mice induced tumor regression but this anti-tumor response was not sustained long-term. Additionally, we demonstrate that only the adoptive transfer of Mammaglobin-A2 specific CD8 T cells in combination with a single low dose of irradiation prevents tumors from recurring. More importantly we show that this single dose of irradiation results in the down regulation of the macrophage scavenger receptor 1 on dendritic cells within the tumor and reduces lipid uptake by tumor resident dendritic cells potentially enabling the dendritic cells to present tumor antigen more efficiently and aid in tumor clearance. These data reveal the potential for adoptive transfer combined with a single low dose of total body irradiation as a suitable therapy for the treatment of established breast tumors and the prevention of tumor recurrence. PMID:22911764

Lerret, Nadine M; Rogozinska, Magdalena; Jaramillo, Andrés; Marzo, Amanda L

2012-07-20

349

Single-Scattering Properties of Mixed-Phase Arctic Clouds at Solar Wavelengths: Impacts on Radiative Transfer  

Microsoft Academic Search

In situ observations of the sizes, shapes, and phases of Arctic clouds were obtained during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) Arctic Clouds Experiment (ACE). These particle distributions were then combined with a library of single-scattering properties, calculated using Mie theory and improved geometric ray optics, to determine the corresponding single-scattering properties (single-scattering albedo v 0,

Greg M. McFarquhar; Stewart G. Cober

2004-01-01

350

Blinking fluorescence of single donor-acceptor pairs: important role of "dark'' states in resonance energy transfer via singlet levels.  

PubMed

The influence of triplet levels on Förster resonance energy transfer via singlet levels in donor-acceptor (D-A) pairs is studied. Four types of D-A pair are considered: (i) two-level donor and two-level acceptor, (ii) three-level donor and two-level acceptor, (iii) two-level donor and three-level acceptor, and (iv) three-level donor and three-level acceptor. If singlet-triplet transitions in a three-level acceptor molecule are ineffective, the energy transfer efficiency E=I_{A}/(I_{A}+I_{D}), where I_{D} and I_{A} are the average intensities of donor and acceptor fluorescence, can be described by the simple theoretical equation E(F)=FT_{D}/(1+FT_{D}). Here F is the rate of energy transfer, and T_{D} is the donor fluorescence lifetime. In accordance with the last equation, 100% of the donor electronic energy can be transferred to an acceptor molecule at FT_{D}?1. However, if singlet-triplet transitions in a three-level acceptor molecule are effective, the energy transfer efficiency is described by another theoretical equation, E(F)=F[over ¯](F)T_{D}/[1+F[over ¯](F)T_{D}]. Here F[over ¯](F) is a function of F depending on singlet-triplet transitions in both donor and acceptor molecules. Expressions for the functions F[over ¯](F) are derived. In this case the energy transfer efficiency will be far from 100% even at FT_{D}?1. The character of the intensity fluctuations of donor and acceptor fluorescence indicates which of the two equations for E(F) should be used to find the value of the rate F. Therefore, random time instants of photon emission in both donor and acceptor fluorescence are calculated by the Monte Carlo method for all four types of D-A pair. Theoretical expressions for start-stop correlators (waiting time distributions) in donor and acceptor fluorescence are derived. The probabilities w_{N}^{D}(t) and w_{N}^{A}(t) of finding N photons of donor and acceptor fluorescence in the time interval t are calculated for various values of the energy transfer rate F and for all four types of D-A pair. Comparison of the calculated D and A fluorescence trajectories with those measured by Weiss and co-workers proves the important role of triplet levels in energy transfer via singlet levels. PMID:23005127

Osad'ko, I S; Shchukina, A L

2012-06-08

351

Blinking fluorescence of single donor-acceptor pairs: Important role of ``dark'' states in resonance energy transfer via singlet levels  

NASA Astrophysics Data System (ADS)

The influence of triplet levels on Förster resonance energy transfer via singlet levels in donor-acceptor (D-A) pairs is studied. Four types of D-A pair are considered: (i) two-level donor and two-level acceptor, (ii) three-level donor and two-level acceptor, (iii) two-level donor and three-level acceptor, and (iv) three-level donor and three-level acceptor. If singlet-triplet transitions in a three-level acceptor molecule are ineffective, the energy transfer efficiency E=IA/(IA+ID), where ID and IA are the average intensities of donor and acceptor fluorescence, can be described by the simple theoretical equation E(F)=FTD/(1+FTD). Here F is the rate of energy transfer, and TD is the donor fluorescence lifetime. In accordance with the last equation, 100% of the donor electronic energy can be transferred to an acceptor molecule at FTD?1. However, if singlet-triplet transitions in a three-level acceptor molecule are effective, the energy transfer efficiency is described by another theoretical equation, E(F)=F¯(F)TD/[1+F¯(F)TD]. Here F¯(F) is a function of F depending on singlet-triplet transitions in both donor and acceptor molecules. Expressions for the functions F¯(F) are derived. In this case the energy transfer efficiency will be far from 100% even at FTD?1. The character of the intensity fluctuations of donor and acceptor fluorescence indicates which of the two equations for E(F) should be used to find the value of the rate F. Therefore, random time instants of photon emission in both donor and acceptor fluorescence are calculated by the Monte Carlo method for all four types of D-A pair. Theoretical expressions for start-stop correlators (waiting time distributions) in donor and acceptor fluorescence are derived. The probabilities wND(t) and wNA(t) of finding N photons of donor and acceptor fluorescence in the time interval t are calculated for various values of the energy transfer rate F and for all four types of D-A pair. Comparison of the calculated D and A fluorescence trajectories with those measured by Weiss and co-workers proves the important role of triplet levels in energy transfer via singlet levels.

Osad'ko, I. S.; Shchukina, A. L.

2012-06-01

352

A study of the transferred hyperfine field and spin lattice relaxation time of [N(CH3)]CuCl4 single crystals  

NASA Astrophysics Data System (ADS)

The molecular susceptibility and paramagnetic shift of [N(CH3)]CuCl4 single crystals were measured, and from these experimental results we obtained the transferred hyperfine interaction, Hhf, due to the spin transfer from Cu ions to [N(CH3)] ions. We conclude that the decrease in Hhf with increasing temperature is not sufficient to allow the spin transfer between Cu ions and the nuclear spins of the nonmagnetic [N(CH3)] ions in the lattice. In addition, the proton spin lattice relaxation time, T1, of [N(CH3)]CuCl4 single crystals was determined as a function of temperature; the variation in T1 with temperature exhibited discontinuities near 263 and 200 K, confirming previous reports of phase transitions at these temperatures. Comparison of the T1 and Hhf results revealed that T1 decreases with increasing Hhf, which is the opposite of the trend reported for [N(CH3)]CoCl4. This difference may be due to differences in the electronic structures of Co and Cu ions: Cu has one s electron outside closed d shells whereas Co has unpaired d electrons, which screen the nuclear charge from the motion of the outer electrons.

Lim, Ae Ran; Lim, Kye-Young

2007-04-01

353

Spray impingement cooling with single- and multiple-nozzle arrays. Part I: Heat transfer data using FC72  

Microsoft Academic Search

With electronic packages becoming more dense and powerful, traditional methods of thermal energy removal are reaching their limits. One method of direct contact cooling capable of removing high heat fluxes while still being compact in size is spray impingement cooling, but its heat transfer behavior is not understood well enough to enable systematic, practical system design. This work presents the

A. G. Pautsch; T. A. Shedd

2005-01-01

354

DNA methylation in the IGF2 intragenic DMR is re-established in a sex-specific manner in bovine blastocysts after somatic cloning.  

PubMed

The recent identification of an intragenic differentially methylated region (DMR) within the last exon of the bovine Insulin-like growth factor 2 (IGF2) gene provides a diagnostic tool for in-depth investigation of bovine imprinting and regulatory mechanisms which are active during embryo development. Here, we used bisulfite sequencing to compare sex-specific DNA methylation patterns within this DMR in bovine blastocysts produced in vivo, by in vitro fertilization and culture, SCNT, androgenesis or parthenogenesis. In in vivo derived embryos, DNA methylation was removed from this intragenic DMR after fertilization, but partially replaced by the time the embryo reached the blastocyst stage. Among embryos developing in vivo, the level of DNA methylation was significantly lower in female than in male blastocysts. This sexual dimorphism was also found between parthenogenetic and androgenetic embryos, and followed the donor cell sex in SCNT derived blastocysts and is evidence for correct methylation reprogramming in SCNT embryos. PMID:19341790

Gebert, Claudia; Wrenzycki, Christine; Herrmann, Doris; Gröger, Daniela; Thiel, Janina; Reinhardt, Richard; Lehrach, Hans; Hajkova, Petra; Lucas-Hahn, Andrea; Carnwath, Joseph W; Niemann, Heiner

2009-03-31

355

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.

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

2011-01-01

356

Differential gene expression in the uterus and blastocyst during the reactivation of embryo development in a model of delayed implantation.  

PubMed

Delayed implantation, a reversible arrest in embryo development while the embryo is at the blastocyst stage, provides an interesting window for observation of the preparation for implantation on both the embryonic and maternal sides. The American mink (Mustela vison) is a species in which delayed implantation is a normal aspect of embryo development as it consistently occurs at each breeding season. We used a transcriptome-wide approach to screen global gene expression and to identify new key genes expressed in the uterus and in the endometrium at the resumption of the embryo development, after delayed implantation. By using the suppressive subtractive hybridization (SSH) technique, two libraries of differentially expressed cDNAs, one at the uterine level and a second one at the blastocyst level, were successfully generated. Candidate genes from those two libraries were selected and their differentially expressed pattern of expression between reactivation and delayed implantation was investigated by real-time PCR and immunolocalization. PMID:19495695

Lefèvre, Pavine L C; Murphy, Bruce D

2009-01-01

357

Cloned calves produced by nuclear transfer from cultured cumulus cells  

Microsoft Academic Search

Short-term cultured cumulus cell lines (1-5BCC) derived from 5 individual cows were used in nuclear transfer (NT) and 1188\\u000a enucleated bovine oocytes matured in vitro were used as nuclear recipients. A total of 931 (78.4%) cloned embryos were reconstructed, of which 763 (82%) cleaved, 627\\u000a (67.3%) developed to 8-cell stage, and 275 (29.5%) reached blastocyst stage. The average cell number

Xiaorong An; Kemian Gou; Shien Zhu; Hong Guan; Jian Hou; Aixing Lin; Shenming Zeng; Jianhui Tian; Yongfu Chen

2002-01-01

358

A serum-free culture system for efficient in vitro production of bovine blastocysts with improved viability after freezing and thawing  

Microsoft Academic Search

The aim of this study was to evaluate whether two completely serum-free media (IVMD101 and IVD101) could improve the yield\\u000a and quality of bovine blastocysts from in vitro matured and fertilized oocytes. The media were evaluated in the presence (IVMD101)\\u000a or absence (IVD101) of bovine cumulus\\/granulosa cell (BCGC) cocultures. The proportion of embryos developing to the blastocyst\\u000a stage in IVMD101

Shoko Yamashita; Hiroyuki Abe; Takehiro Itoh; Takeshi Satoh; Hiroyoshi Hoshi

1999-01-01

359

Protective effects of resveratrol on ethanol-induced apoptosis in embryonic stem cells and disruption of embryonic development in mouse blastocysts  

Microsoft Academic Search

Previous studies have established that ethanol induces apoptosis, but the precise molecular mechanisms are currently unclear. Here, we show that 0.3–1.0% (w\\/v) ethanol induces apoptosis in mouse blastocysts and that resveratrol, a grape-derived phytoalexin with known antioxidant and anti-inflammatory properties, prevents ethanol-induced apoptosis and inhibition of cell proliferation. Moreover, ethanol-treated blastocysts show normal levels of implantation on culture dishes in

Lien-Hung Huang; Nion-Heng Shiao; Yan-Der Hsuuw; Wen-Hsiung Chan

2007-01-01

360

Effect of the bovine oviductal fluid on in vitro fertilization, development and gene expression of in vitro-produced bovine blastocysts.  

PubMed

Oviductal microenvironment generally provides better conditions for early embryo development than the conventional in vitro system. In an attempt to simulate the oviduct conditions or the main potentially influencing factors, the effect was studied of a bovine oviductal fluid (bOF) treatment applied prior to IVF on (i) IVF parameters, (ii) cleavage rate, (iii) blastocyst yield and (iv) blastocyst quality. Embryo quality was assessed by morphological embryo quality and relative transcript abundance of several developmental genes in bovine blastocysts. Furthermore, to study the effect of bOF without the male effect and zona-sperm interaction, artificially activated metaphase II oocytes were also treated with bOF. In vitro-matured bovine oocytes from abattoir ovaries were treated or untreated with bOF for 30 min and then washed prior to IVF or activation. Subsequently, in vitro-fertilized and parthenogenetic embryos were in vitro cultured for 7 to 8 days. The bOF treatment had no effect on fertilization parameters, cleavage, blastocyst rates both on parthenogenetic and IVF bovine embryos and neither on morphological quality of IVF blastocysts. G6PD and SOD2 genes from IVF blastocysts showed significant changes in their expression after a bOF treatment. Significant differences were found for the expression of SCL2A1, GPX1, BAX, AKR1B1 and PLAC8 genes between excellent or good blastocysts (Grade 1) and fair blastocysts (Grade 2). To our knowledge, this is the first study that evaluates the effect of bOF oocyte treatment on fertilization parameters, development and quality of bovine embryos. PMID:22908847

Cebrian-Serrano, A; Salvador, I; García-Roselló, E; Pericuesta, E; Pérez-Cerezales, S; Gutierrez-Adán, A; Coy, P; Silvestre, M A

2012-08-22

361

The single-molecule conductance and electrochemical electron-transfer rate are related by a power law.  

PubMed

This study examines quantitative correlations between molecular conductances and standard electrochemical rate constants for alkanes and peptide nucleic acid (PNA) oligomers as a function of the length, structure, and charge transport mechanism. The experimental data show a power-law relationship between conductances and charge transfer rates within a given class of molecules with the same bridge chemistry, and a lack of correlation when a more diverse group of molecules is compared, in contrast with some theoretical predictions. Surprisingly, the PNA duplexes exhibit the lowest charge-transfer rates and the highest molecular conductances. The nonlinear rate-conductance relationships for structures with the same bridging chemistries are attributed to differences in the charge-mediation characteristics of the molecular bridge, energy barrier shifts and electronic dephasing, in the two different experimental settings. PMID:23692478

Wierzbinski, Emil; Venkatramani, Ravindra; Davis, Kathryn L; Bezer, Silvia; Kong, Jing; Xing, Yangjun; Borguet, Eric; Achim, Catalina; Beratan, David N; Waldeck, David H

2013-05-30

362

Monochorionic-triamniotic triplet pregnancy after intracytoplasmic sperm injection, assisted hatching, and two-embryo transfer: first reported case following IVF  

Microsoft Academic Search

BACKGROUND: We present a case of monochorionic-triamniotic pregnancy that developed after embryo transfer following in vitro fertilization (IVF). METHODS: After controlled ovarian hyperstimulation and transvaginal retrieval of 22 metaphase II oocytes, fertilization was accomplished with intracytoplasmic sperm injection (ICSI). Assisted embryo hatching was performed, and two embryos were transferred in utero. One non-transferred blastocyst was cryopreserved. RESULTS: Fourteen days post-transfer,

Labib M Ghulmiyyah; Mark Perloe; Michael J Tucker; Julie H Zimmermann; Daniel P Eller; E Scott Sills

2003-01-01

363

Saturation of power transfer between two copropagating laser beams by ion-wave scattering in a single-species plasma  

Microsoft Academic Search

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 (<=2.5×1014 W\\/cm2) beam intersected by a high-intensity (7.0×1014 W\\/cm2) pump beam is determined by comparing the transmitted beam power to that

R. K. Kirkwood; E. A. Williams; B. I. Cohen; L. Divol; M. R. Dorr; J. A. Hittinger; A. B. Langdon; C. Niemann; J. Moody; L. J. Suter; O. L. Landen

2005-01-01

364

Naphthalenedicarboxamides as fluorescent probes of inter- and intramolecular electron transfer in single strand, hairpin, and duplex DNA  

Microsoft Academic Search

The 2,6-naphthalenedicarboxamide chromophore has been investigated as a fluorescent probe for DNA hairpin and duplex formation and DNA electron transfer. The high fluorescence quantum yield and long singlet lifetime of this chromophore make it an attractive candidate for these studies. The kinetics of intermolecular quenching of a naphthalenedicarboxamide by nucleosides is dependent upon the nucleoside oxidation potential and solvent. Bis(oligonucleotide)

Frederick D. Lewis; Yifan Zhang; Xiaoyang Liu; Ning Xu; Robert L. Letsinger

1999-01-01

365

Convective heat transfer in single-phase flow in a vertical tube subjected to axial low frequency oscillations  

Microsoft Academic Search

The effect of oscillations on the heat transfer in a vertical tube has been studied experimentally. A vertical tube was mounted\\u000a on a plate and the whole plate was subjected to oscillations in the vertical plane using a mechanical oscillator to provide\\u000a low frequency oscillations. A section of the tube in the middle is subjected to a constant heat flux.

Rajashekhar Pendyala; Sreenivas Jayanti; A. R. Balakrishnan

2008-01-01

366

Condensation Heat Transfer and Pressure Losses of High and Low-Pressure Refrigerants Flowing in a Single Circular Minichannel  

Microsoft Academic Search

A 0.96 mm circular minichannel is used to measure both heat transfer coefficients during condensation and two-phase pressure losses of the refrigerants R32 and R245fa. Test runs have been performed at around 40°C saturation temperature, corresponding to 24.8 bar saturation pressure for R32 and 2.5 bar saturation pressure for R245fa. The pressure drop tests have been performed in adiabatic flow

Alberto Cavallini; Stefano Bortolin; Davide Del Col; Marko Matkovic; Luisa Rossetto

2011-01-01

367

Single-walled carbon nanotube-induced crystallinity on the electropolymeric film of tetraaminophthalocyaninatonickel(II) complex: Impact on the rate of heterogeneous electron transfer  

NASA Astrophysics Data System (ADS)

We present a fundamental investigation on the impact of single-walled carbon nanotube (SWCNT) on the film structure and redox behaviour of tetraaminophthalocyaninatonickel(II) complex (NiTAPc) electropolymer immobilized on a basal plane pyrolytic graphite electrode (BPPGE). SWCNT induces crystallinity on the NiTAPc electropolymeric film structure and increases its apparent electron transfer rate constant ( kapp). We proved that there is potential advantage of using electrode based on the SWCNT- poly-NiTAPc hybrid for catalytic and sensing applications as it enhances the catalytic current for the detection of nitric oxide more than twice compared to bare BPPGE, BPPGE-SWCNT and other electrodes without SWCNTs.

Pillay, Jeseelan; Ozoemena, Kenneth I.

2007-06-01

368

Trophoblast Adhesion of the Peri-implantation Mouse Blastocyst is Regulated by Integrin Signaling That Targets Phospholipase C  

PubMed Central

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 receptor (Xestospongin C) inhibited FN-induced elevation of intracellular Ca2+ and prevented the upregulation of FN-binding activity. In contrast, inhibitors of Ca2+ influx through either voltage-gated or non-voltage-gated Ca2+ channels were without effect. Inhibition of protein tyrosine kinase activity by genistein, but not G-protein inhibition by suramin, blocked FN-induced intracellular Ca2+ signaling and upregulation of adhesion, consistent with involvement of PLC-?. Confocal immunofluorescence imaging of peri-implantation blastocysts demonstrated that PLC-?2, but not PLC-?1 nor PLC-?1, accumulated near the outer surface of the embryo. Phosphotyrosine site-directed antibodies revealed phosphorylation of PLC-?2, but not PLC-?1, upon integrin ligation by FN. These data suggest that integrin-mediated activation of PLC-? to initiate phosphoinositide signaling and intracellular Ca2+ mobilization is required for blastocyst adhesion to FN. Signaling cascades regulating PLC-? could, therefore, control a critical feature of trophoblast differentiation during peri-implantation development.

Wang, Jun; Mayernik, Linda; Armant, D. Randall

2007-01-01

369

Junctional Adhesion Molecule 2 Mediates the Interaction between Hatched Blastocyst and Luminal Epithelium: Induction by Progesterone and LIF  

PubMed Central

Background Junctional adhesion molecule 2 (Jam2) is a member of the JAM superfamily. JAMs are localized at intercellular contacts and participated in the assembly and maintenance of junctions, and control of cell permeability. Because Jam2 is highly expressed in the luminal epithelium on day 4 of pregnancy, this study was to determine whether Jam2 plays a role in uterine receptivity and blastocyst attachment in mouse uterus. Methodology/Principal Findings Jam2 is highly expressed in the uterine luminal epithelium on days 3 and 4 of pregnancy. Progesterone induces Jam2 expression in ovariectomized mice, which is blocked by progesterone antagonist RU486. Jam2 expression on day 4 of pregnancy is also inhibited by RU486 treatment. Leukemia inhibitory factor (LIF) up-regulates Jam2 protein in isolated luminal epithelium from day 4 uterus, which is blocked by S3I-201, a cell-permeable inhibitor for Stat3 phosphorylation. Under adhesion assay, recombinant Jam2 protein increases the rate of blastocyst adhesion. Both soluble recombinant Jam2 and Jam3 can reverse this process. Conclusion Jam2 is highly expressed in the luminal epithelium of receptive uterus and up-regulated by progesterone and LIF via tyrosine phosphorylation of Stat3. Jam2 may play a role in the interaction between hatched blastocyst and receptive uterus.

Su, Ren-Wei; Jia, Bo; Ni, Hua; Lei, Wei; Yue, Shun-Li; Feng, Xu-Hui; Deng, Weng-Bo; Liu, Ji-Long; Zhao, Zhen-Ao; Wang, Tong-Song; Yang, Zeng-Ming

2012-01-01

370

Oct4 cell-autonomously promotes primitive endoderm development in the mouse blastocyst.  

PubMed

In embryonic stem (ES) cells and in early mouse embryos, the transcription factor Oct4 is an essential regulator of pluripotency. Oct4 transcriptional targets have been described in ES cell lines; however, the molecular mechanisms by which Oct4 regulates establishment of pluripotency in the epiblast (EPI) have not been fully elucidated. Here, we show that neither maternal nor zygotic Oct4 is required for the formation of EPI cells in the blastocyst. Rather, Oct4 is first required for development of the primitive endoderm (PE), an extraembryonic lineage. EPI cells promote PE fate in neighboring cells by secreting Fgf4, and Oct4 is required for expression of Fgf4, but we show that Oct4 promotes PE development cell-autonomously, downstream of Fgf4 and Mapk. Finally, we show that Oct4 is required for the expression of multiple EPI and PE genes as well as multiple metabolic pathways essential for the continued growth of the preimplantation embryo. PMID:23747191

Frum, Tristan; Halbisen, Michael A; Wang, Chaoyang; Amiri, Hossein; Robson, Paul; Ralston, Amy

2013-06-06

371

Epigenetic differences between embryonic stem cells generated from blastocysts developed in vitro and in vivo.  

PubMed

Embryonic stem (ES) cells constitute a very important tool for regenerative medicine today. These ES cells, and human ES cells in particular, are almost all derived from embryos obtained by in vitro fertilization (IVF) and from in vitro culture (IVC); however, such in vitro manipulated embryos often show abnormal genomic imprinting, which can lead to the development of various diseases. Nevertheless, several reports have evaluated ES cells derived from in vitro manipulated embryos. In this study, we established ES cells derived from both in vivo and in vitro developed blastocysts (Vivo ES cells and Vitro ES cells, respectively) to compare the methylation status of imprinted genes and gene expression patterns. At very early passages, Vitro ES cells showed an increase in abnormal genomic imprinting compared to Vivo ES cells. In addition, we found that the gene expression patterns of several methylation related-genes frequently shifted to promote demethylation and to inhibit methylation in early-passage Vitro ES cells. In contrast, at later passages, we found no significant differences between Vivo and Vitro ES cells. In conclusion, it is advisable to use early passage Vivo ES cells whenever feasible, or to select ES cell lines with a normal epigenotype. PMID:20818993

Horii, Takuro; Yanagisawa, Eikichi; Kimura, Mika; Morita, Sumiyo; Hatada, Izuho

2010-10-01

372

Imaging proprotein convertase activities and their regulation in the implanting mouse blastocyst  

PubMed Central

Axis formation and allocation of pluripotent progenitor cells to the germ layers are governed by the TGF-?–related Nodal precursor and its secreted proprotein convertases (PCs) Furin and Pace4. However, when and where Furin and Pace4 first become active have not been determined. To study the distribution of PCs, we developed a novel cell surface–targeted fluorescent biosensor (cell surface–linked indicator of proteolysis [CLIP]). Live imaging of CLIP in wild-type and Furin- and Pace4-deficient embryonic stem cells and embryos revealed that Furin and Pace4 are already active at the blastocyst stage in the inner cell mass and can cleave membrane-bound substrate both cell autonomously and nonautonomously. CLIP was also cleaved in the epiblast of implanted embryos, in part by a novel activity in the uterus that is independent of zygotic Furin and Pace4, suggesting a role for maternal PCs during embryonic development. The unprecedented sensitivity and spatial resolution of CLIP opens exciting new possibilities to elucidate PC functions in vivo.

Mesnard, Daniel

2010-01-01

373

[Program optimization for bovine somatic cells nuclear transfer].  

PubMed

To optimize program of bovine somatic nuclear transfer, we used two different enucleation procedures (by Spindle-view system & Hoechst 33342 staining), two different procedures to introduce donor nuclei (by ooplasm microinjection & electrofusion), and three different group electrofusion parameters (group 1: 1.9 kV/cm, 10 micros, two; group 2: 1.5 kV/cm, 25 micros, two; group 3: 0.6 kV/cm, 100 micros, one) to reconstruct bovine cloned embryos. The cleavation rates and blastocyst development rates of cloned embryos were used to assess the efficiency of different operational procedure. Finally, the best combination of operational procedure, that the spindle-viewer system was used for oocytes enucleating, and donor cell was electrofused into ooplasm by electrical pulse (1.9 kV/cm, 10 micros, two) to reconstruct bovine cloned embryos. Then the excellent blastocysts were transferred to fosters for producing cloned cattle 80 high-quality cloned blastocysts were transferred into 33 fosters, two cloned calves were produced. According to the results, the optimized program could be used to produce cloned cattle. PMID:19938488

Lei, Anmin; Ma, Xiaoling; Gao, Zhimin; Hu, Yongce; Sui, Jinqiang; Huang, Weiwei; Zan, Linsen; Dou, Zhongying

2009-09-01

374

Silver transfer in proustite Ag{sub 3}AsS{sub 3} at high temperatures: Conductivity and single-crystal X-ray studies  

SciTech Connect

Single crystals of proustite Ag{sub 3}AsS{sub 3} have been characterised by impedance spectroscopy and single-crystal X-ray diffraction in the temperature ranges of 295-543 and 295-695 K, respectively. An analysis of the one-particle potential of silver atoms shows that in the whole measuring temperature range defects in the silver substructure play a major role in the conduction mechanism. Furthermore, the silver transfer is equally probable within silver chains and spirals, as well as between chains and spirals. The trigonal R3c room temperature phase does not change until the decomposition of the crystal. The electric anomaly of the first-order character which appears near 502 K is related to an increase in the electronic component of the total conductivity resulting from Ag{sub 2}S deposition at the sample surface. - Joint probability density function map of silver atoms at T=695 K.

Gagor, Anna [W. Trzebiatowski Institute of Low Temperature and Structure Research PAS, P.O. Box 1410, 50-950 Wroclaw (Poland)], E-mail: a.gagor@int.pan.wroc.pl; Pawlowski, Antoni [Institute of Molecular Physics PAS, Mariana Smoluchowskiego 17, 60-179 Poznan (Poland); Pietraszko, Adam [W. Trzebiatowski Institute of Low Temperature and Structure Research PAS, P.O. Box 1410, 50-950 Wroclaw (Poland)

2009-03-15

375

Preliminary assessment of somatic cell nuclear transfer in the dromedary (Camelus dromedarius).  

PubMed

Somatic cloning may enable the maintenance/expansion of the population of camels with the highest potential for milk production or the best racing performances. However, there have been no reports of embryonic or somatic nuclear transfer in camels. The aim of this study was to produce dromedary embryos by nuclear transfer using in vitro matured oocytes and two somatic cells from two sources (adult fibroblasts or granulosa cells). A total of 58 adult females were superstimulated by a single dose of eCG (3500 IU). Ten days later, their ovaries were collected postmortem. Cumulus-oocytes-complexes (COCs) were aspirated from stimulated follicles and were matured in vitro for 30 h. Fibroblasts (from live adult male) and granulosa cells (from slaughtered adult females) were used as donor karyoplasts and injected into mature enucleated dromedary oocytes. The cleavage rate was significantly higher (P<0.05) for embryos reconstructed with fibroblasts (59%) versus those with granulosa cells (45%). However, there was no difference between the two groups in the proportion of cloned embryos reaching the blastocyst stage (fibroblasts: 14% vs. granulosa cells: 15%) or those that hatched (fibroblasts: 10% vs. granulosa cells: 12%). The viability of reconstructed dromedary embryos from the two sources of donor cells (fibroblasts; n=5 vs. granulosa cells; n=7) was examined by transferring them to synchronized recipients. Two females (fibroblasts: 1/5; 20%, granulosa cells: 1/7; 14%) were confirmed pregnant by ultrasonography at 15 and 25 days following transfer. Later, the pregnancies were followed by pregnancy empirical-symptoms. These two pregnancies were lost between 25 and 60 days following transfer, respectively. In conclusion, the present study shows for the first time that the development of dromedary NT embryos derived from either adult fibroblasts or granulosa cells can occur in vitro and the transfer of these cloned embryos to recipients can result in pregnancies. PMID:18675449

Khatir, H; Anouassi, A

2008-12-01

376

Autologous somatic cell nuclear transfer in pigs using recipient oocytes and donor cells from the same animal  

Microsoft Academic Search

The objective of the present study was to examine the feasibility of the production of autologous porcine somatic cell nuclear transfer (SCNT) blastocysts using oocytes and donor cells from slaughtered ovaries. Therefore, we at- tempted to optimize autologous SCNT by examining the effects of electrical fusion conditions and donor cell type on cell fusion and the development of SCNT embryos.

Eunsong Lee; Kilyoung Song

2007-01-01

377

Adoptive T-cell transfer combined with a single low dose of total body irradiation eradicates breast tumors.  

PubMed

The major objectives of tumor vaccination are to induce the regression of established tumors and to favor the establishment of long-lasting tumor-specific immunity, capable of protecting the host from relapse. Immunotherapeutic strategies such as the administration of tumor-associated antigenic peptides offer one means to boost preexisting antitumor CD8(+) T cell immunity. Our recent work reveals that established breast tumors are rejected and tumor recurrence prevented when low-dose irradiation is combined with the adoptive transfer of Mammaglobin A epitope-specific CD8(+) T cells. PMID:23525138

Lerret, Nadine M; Marzo, Amanda L

2013-02-01

378

Adoptive T-cell transfer combined with a single low dose of total body irradiation eradicates breast tumors  

PubMed Central

The major objectives of tumor vaccination are to induce the regression of established tumors and to favor the establishment of long-lasting tumor-specific immunity, capable of protecting the host from relapse. Immunotherapeutic strategies such as the administration of tumor-associated antigenic peptides offer one means to boost preexisting antitumor CD8+ T cell immunity. Our recent work reveals that established breast tumors are rejected and tumor recurrence prevented when low-dose irradiation is combined with the adoptive transfer of Mammaglobin A epitope-specific CD8+ T cells.

Lerret, Nadine M.; Marzo, Amanda L.

2013-01-01

379

In vitro production of bovine embryos and their application for embryo transfer  

Microsoft Academic Search

This review introduces newly developed serum-free media (IVD101 and IVMD101), that are effective for producing high yields of transferable embryos of good quality from in vitro-matured and -fertilized oocytes. Both serum-free media produced better results than serum-containing medium, including increased rates of blastocyst formation, post-thaw embryo viability, and pregnancy after transfer. In addition, reduced risks of calf mortality and large

Hiroyoshi Hoshi

2003-01-01

380

pH-Sensitive Photoinduced Energy Transfer from Bacteriorhodopsin to Single-Walled Carbon Nanotubes in SWNT-bR Hybrids.  

PubMed

Energy transfer mechanisms in noncovalently bound bacteriorhodopsin/single-walled carbon nanotube (SWNT) hybrids are investigated using optical absorption and photoluminescence excitation measurements. The morphology of the hybrids was investigated by atomic force microscopy. In this study, proteins are immobilized onto the sidewall of the carbon nanotubes using a sodium cholate suspension-dialysis method that maintains the intrinsic optical and fluorescence properties of both molecules. The hybrids are stable in aqueous solutions for pH ranging from 4.2 to 9 and exhibit photoluminescence properties that are pH-dependent. The study reveals that energy transfer from bacteriorhodopsin to carbon nanotubes takes place. So, at pH higher than 5 and up to 9, the SWNTs absorb the photons emitted by the aromatic residues of the protein, inducing a strong increase in intensity of the E11 emissions of SWNTs through their E33 and E44 excitations. From pH = 4.2 to pH = 5, the protein fluorescence is strongly quenched whatever the emission wavelengths, while additional fluorescence features appear at excitation wavelengths ranging from 660 to 680 nm and at 330 nm. The presence of these features is attributed to a resonance energy transfer mechanism that has an efficiency of 0.94 ± 0.02. More, by increasing the pH of the dispersion, the fluorescence characteristics become those observed at higher pH values and vice versa. PMID:24011351

El Hadj, Karim; Bertoncini, Patricia; Chauvet, Olivier

2013-09-13

381

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

SciTech Connect

We report a low-temperature (350 deg. C) anodic bonding followed by grind/etch-back method for a 200 mm wafer-scale epitaxial transfer of ultrathin (1.9 kA) single crystalline Si on Pyrex glass. Standard back-end-of-line 3 kA SiN/3 kA 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. [Semiconductor Process Technologies Laboratory, Institute of Microelectronics (IME), 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore)

2005-08-15

382

Lack of beta 1 integrin gene in embryonic stem cells affects morphology, adhesion, and migration but not integration into the inner cell mass of blastocysts  

PubMed Central

A gene trap-type targeting vector was designed to inactivate the beta 1 integrin gene in embryonic stem (ES) cells. Using this vector more than 50% of the ES cell clones acquired a disruption in the beta 1 integrin gene and a single clone was mutated in both alleles. The homozygous mutant did not produce beta 1 integrin mRNA or protein, while alpha 3, alpha 5, and alpha 6 integrin subunits were transcribed but not detectable on the cell surface. Heterozygous mutants showed reduced beta 1 expression and surface localization of alpha/beta 1 heterodimers. The alpha V subunit expression was not impaired on any of the mutants. Homozygous ES cell mutants lacked adhesiveness for laminin and fibronectin but not for vitronectin and showed a reduced association with a fibroblast feeder layer. Furthermore, they did not migrate towards chemoattractants in fibroblast medium. None of these functions were impaired in heterozygous mutants. Scanning electron microscopy revealed that homozygous cells showed fewer cell-cell junctions and had many microvilli not usually found on wild type and heterozygous cells. This profound change in cell shape is not associated with gross alterations in the expression and distribution of cytoskeletal components. Unexpectedly, microinjection into blastocysts demonstrated full integration of homozygous and heterozygous mutants into the inner cell mass. This will allow studies of the consequences of beta 1 integrin deficiency in several in vivo situations.

1995-01-01

383

Blastocyst production by in vitro maturation and development of porcine oocytes in defined media following intracytoplasmic sperm injection.  

PubMed

The present study was carried out to establish porcine defined IVP. In Experiments 1 and 2, we investigated the efficacy of additional 0.6 mM cystine and/or 100 microM cysteamine (Cys) to a defined TCM199 maturation medium with regard to the intracellular glutathione (GSH) concentration and the developmental competence of in vitro matured porcine oocytes following intracytoplasmic sperm injection (ICSI). The control medium was a modified TCM199 containing 0.05% (w/v) polyvinyl alcohol (PVA). Cys and/or cystine were added to the control medium. The control group and immature oocytes (presumptive germinal vesicle oocytes; GV) were prepared for GSH assay. In Experiment 3, the efficacy of epidermal growth factor (EGF) addition to a modified porcine zygote medium (mPZM) for in vitro culture (IVC) medium was investigated on embryonic development and the mean cell number of blastocysts following ICSI. As a positive or negative control, 0.3% BSA (mPZM-3) or 0.3% PVA (mPZM-4), respectively, was added to the base medium. The defined IVC medium was supplemented with 5 or 10 ng/ml EGF. In Experiment 1, no significant difference was found in the rates of cleavage (31.4-64.3%) and blastocyst formation (6.5-22.9%) among the treatment and control groups. The mean cell numbers per blastocyst ranged from 30 to 48 among the groups without significant differences. However, in Experiment 2, the intracellular GSH concentrations in the oocytes cultured in the medium supplemented with 100 microM Cys (9.6 pmol/oocyte) or Cys + cystine (9.9 pmol/oocyte) were significantly (p < 0.05) higher than the control (2.5 pmol/oocyte) and 0.6 mM cystine (6.5 pmol/oocyte) groups, but not different from the GV group (9.0 pmol/oocyte). The GSH concentration in the cystine group was also significantly (p < 0.05) higher than that in the control group, but not different from the GV group. In Experiment 3, the rates of cleavage and blastocyst formation and the mean cell numbers of blastocysts were not significantly different among the groups. However, the addition of 5 ng/ml EGF into the mPZM-4 resulted in a significantly (p < 0.05) higher blastocyst rate per cleaved embryo than the other two defined groups (mPZM-4 + 5 ng/ml: 48.6%, mPZM-4 and mPZM-4 +10 ng/ml: 23.4% and 23.1%, respectively). The present results indicate that the addition of Cys to a defined medium for in vitro maturation (IVM) of porcine oocytes increases intracellular GSH concentration. Further addition of cystine into the IVM medium containing 100 microM Cys is not necessary and TCM199 plus Cys (100 microM) could be used as a defined IVM medium for porcine oocytes. The addition of 5 ng/ml EGF to a defined IVC medium has enhanced subsequent development after ICSI. This study shows that porcine blastocysts can be produced by defined media throughout the steps of IVP (IVM, ICSI and IVC). PMID:17462101

Kobayashi, M; Asakuma, S; Fukui, Y

2007-05-01

384

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

385

Improved detection of aneuploid blastocysts using a new 12-chromosome FISH test.  

PubMed

Fluorescence in-situ hybridization (FISH) has been the principal method used for the identification and preferential transfer of chromosomally normal embryos, in the context of both preimplantation genetic diagnosis (PGD) and screening (PGS). Generally, the probe combinations used during PGS have focused on chromosomes frequently identified as abnormal in prenatal samples or material derived from first-trimester spontaneous abortions. Recent data, however, obtained with the use of comparative genomic hybridization (CGH), have suggested that commonly used PGS strategies may fail to detect a large number of aneuploidies affecting preimplantation embryos. Some chromosomes, which have been relatively neglected in PGS protocols thus far, display a disproportionate contribution to embryo aneuploidy and should be prioritized for screening. Using CGH data, it is possible to design new probe combinations that examine between 10 and 12 chromosomes and are capable of accurately diagnosing 89-91% of anomalies seen in embryos. At present, 24-chromosome tests, such as CGH, array CGH or single nucleotide polymorphism arrays, remain relatively costly and, in some cases, are yet to be fully validated. For these reasons, a cost-effective method, capable of accurately detecting almost all aneuploid embryos, represents an attractive alternative to comprehensive chromosome screening approaches. PMID:20158993

Munné, S; Fragouli, E; Colls, P; Katz-Jaffe, Mg; Schoolcraft, Wb; Wells, D

2009-10-31

386

Fe2+-Ti4+ vs. Fe2+-Fe3+ charge-transfer and short-range order in single chains of face-sharing octahedra: ellenbergerite and dumortierite  

NASA Astrophysics Data System (ADS)

In zoned pyrope megacrysts from the Dora-Maira UHP terrane, new, dark-violet colour varieties of the hexagonal, high-pressure silicate ellenbergerite extend the range of known Fe contents for this mineral from 0-0.1 to 0-0.4 atom pfu, for Ti contents commonly in the range 0.2-0.4 pfu. The new varieties show an extremely intense pleochroism, colourless for E perpendicular to c to deep Prussian blue for E//c, as compared to colourless to lilac or reddish purple for classical Fe-poor ellenbergerite. These features were the incentive for an electronic absorption spectroscopic study and a reappraisal of the interpretation of the charge transfers (CT), colour and ordering schemes in this group and the structurally related borosilicate dumortierite. Both structures are characterized by the presence of infinite single chains of face-sharing, partly vacant octahedra along the 6-fold screw axis and pseudo-hexad axis, respectively, in which the Fe and Ti atoms are partitioned. In the spectra of Fe-poor ellenbergerite, the presence of a single Fe2+-Ti4+ CT band near 19000 cm?1 was taken as evidence for complete short-range ordering of Mg(Fe), Ti and vacancies in the octahedral single chain [1]. The E//c spectra of Fe-rich ellenbergerite show the same absorption band near 19000 cm?1 but consistently flanked by another CT band near 14000 cm?1 , the intensity of which increases with total Fe content. The latter is similar to the 12400 cm?1 CT band observed as the single feature in E//c spectra of the isotructural (Ti-free and Fe-bearing) phosphoellenbergerite, and clearly assigned to Fe2+-Fe3+ CT in the octahedral single chain [1]. The same colour pattern occurs in the dumortierite group, with red Fe-poor, Ti-rich crystals showing a single CT band near 20000 cm?1, blue Ti-poor crystals showing a single CT band near 16500 cm?1, and violet Fe- and Ti-rich crystals showing a combination of the two bands [2]. In the light of the new data, we reinterpret the dumortierite colour scheme as due to both Fe2+-Fe3+ (16500 cm?1) and Fe2+-Ti4+ (20000 cm?1) CT, rather than to Fe2+-Ti4+ CT only with two extreme types of Fe-Ti dimers [- v - Fe2+ - Ti4+ - v -] and [- M - Fe2+ - Ti4+ - v -], where v stands for vacancy. We discuss the implications in terms of energy and of short-range ordering of vacancies in the octahedral single chains of the ellenbergerite and dumortierite groups. Optical spectroscopy appears as a very sensitive structural probe of minor or trace elements. [1] Chopin C. & Langer, K. (1988): Fe2+-Ti4+ charge transfer between face-sharing octahedra: polarized absorption spectra and crystal chemistry of ellenbergerite. Bull. Minéral., 111, 17-27. [2] Platonov, A.N., Langer, K., Chopin, C., Andrut, M., Taran, M.N. (2000): Fe2+-Ti4+ charge-transfer in dumortierite. Eur. J. Mineral., 12, 521-528.

Chopin, C.; Langer, K.; Khomenko, V.

2009-04-01

387

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

2013-06-07

388

Tutorial on Quantification of Differences between Single and Two-Component Two-Phase Flow and Heat Transfer  

Microsoft Academic Search

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In

A. A. M. Delil

2003-01-01

389

Colcemid-treatment of heifer oocytes enhances nuclear transfer embryonic development, establishment of pregnancy and development to term.  

PubMed

Four experiments were designed to examine the effects of colcemid, a microtubule assembly inhibitor, on the development of bovine nuclear transfer (NT) embryos in vitro and in vivo. Recipient oocytes matured at different times were exposed to colcemid. Approximately 80-93% of the exposed oocytes, with or without the first polar body (PB1), developed obvious membrane projections. In Experiment 1, oocytes matured for either 14-15 or 16-17 hr, treated with colcemid and used as recipient cytoplasm for NT resulted in over 40% blastocyst development. In Experiment 2, oocytes matured for 16-17 hr were treated with either 0.2 or 0.4 microg/ml colcemid for 2-3 or 5-6 hr, respectively. The percentages of blastocyst development (39-42%) were not statistically different among the different colcemid treatment groups, but were both higher (P < 0.05) than the control group (30%). Colcemid concentrations and length of colcemid treatment of oocytes did not affect their ability to support NT embryo development to the blastocyst and hatched blastocyst stages. Results from Experiment 3 indicate that semi-defined medium increases morula and blastocyst development of NT embryos derived from colcemid-treated oocytes under 5% CO2 in air atmosphere. In addition, cell numbers of blastocysts in colcemid-treated groups were numerically higher than the control groups. After embryo transfer, higher (P < 0.05) pregnant rates were obtained from the colcemid-treated group than the nontreated group. Five of 40 recipients (12.5%) which received embryos from colcemid-treated oocytes delivered healthy calves, significantly higher than those recipients (3.3%) that received embryos derived from nontreated oocytes. PMID:19170231

Li, Guang-Peng; White, Kenneth L; Aston, Kenneth I; Bunch, Thomas D; Hicks, Brady; Liu, Ying; Sessions, Benjamin R

2009-07-01

390

Single-dose pharmacokinetics and pharmacodynamics of anacetrapib, a potent cholesteryl ester transfer protein (CETP) inhibitor, in healthy subjects  

PubMed Central

AIMS Anacetrapib is an orally active and potent inhibitor of CETP in development for the treatment of dyslipidaemia. These studies endeavoured to establish the safety, tolerability, pharmacokinetics and pharmacodynamics of rising single doses of anacetrapib, administered in fasted or fed conditions, and to preliminarily assess the effect of food, age, gender and obesity on the single-dose pharmacokinetics and pharmacodynamics of anacetrapib. METHODS Safety, tolerability, anacetrapib concentrations and CETP activity were evaluated. RESULTS Anacetrapib was rapidly absorbed, with peak concentrations occurring at ?4 h post-dose and an apparent terminal half-life ranging from ?9 to 62 h in the fasted state and from ?42 to ?83 h in the fed state. Plasma AUC and Cmax appeared to increase in a less than approximately dose-dependent manner in the fasted state, with an apparent plateau in absorption at higher doses. Single doses of anacetrapib markedly and dose-dependently inhibited serum CETP activity with peak effects of ?90% inhibition at tmax and ?58% inhibition at 24 h post-dose. An Emax model best described the plasma anacetrapib concentration vs CETP activity relationship with an EC50 of ?22 nm. Food increased exposure to anacetrapib; up to ?two–three-fold with a low-fat meal and by up to ?six–eight fold with a high-fat meal. Anacetrapib pharmacokinetics and pharmacodynamics were similar in elderly vs young adults, women vs men, and obese vs non-obese young adults. Anacetrapib was well tolerated and was not associated with any meaningful increase in blood pressure. CONCLUSIONS Whereas food increased exposure to anacetrapib significantly, age, gender and obese status did not meaningfully influence anacetrapib pharmacokinetics and pharmacodynamics.

Krishna, Rajesh; Garg, Amit; Panebianco, Deborah; Cote, Josee; Bergman, Arthur J; Van Hoydonck, Pascale; Laethem, Tine; Van Dyck, Kristien; Chen, Jingjing; Chavez-Eng, Cynthia; Archer, Laura; Lutz, Ryan; Hilliard, Deborah; Snyder, Karen; Jin, Bo; Van Bortel, Luc; Lasseter, Kenneth C; Al-Huniti, Nidal; Dykstra, Kevin; Gottesdiener, Keith; Wagner, John A

2009-01-01

391

Comparison of HYDRA predictions to temperature data from two single-assembly spent fuel heat transfer tests  

SciTech Connect

The HYDRA computer code was used to simulate the thermal performance of an actual and a model spent fuel assembly. The HYDRA-predicted temperatures were then compared with measured data from two single-assembly test sections. The objective of this effort was to further verify the predictive capabilities of the HYDRA code for use in assessments of the hydrothermal performance of spent fuel dry storage systems. After HYDRA has been adequately evaluated and validated, the code will be documented to permit design and licensing safety analyses.

McCann, R.A.

1986-12-01

392

A single methionine residue dictates the kinetic mechanism of interprotein electron transfer from methylamine dehydrogenase to amicyanin.  

PubMed

Amicyanin is a type 1 copper protein that is the natural electron acceptor for the quinoprotein methylamine dehydrogenase (MADH). A P52G amicyanin mutation increased the Kd for complex formation and caused the normally true electron transfer (ET) reaction from O-quinol MADH to amicyanin to become a gated ET reaction (Ma, J. K., Carrell, C. J., Mathews, F. S., and Davidson, V. L. (2006) Biochemistry 45, 8284-8293). One consequence of the P52G mutation was to reposition the side chain of Met51, which is present at the MADH-amicyanin interface. To examine the precise role of Met51 in this interprotein ET reaction, Met51 was converted to Ala, Lys, and Leu. The Kd for complex formation of M51A amicyanin was unchanged but the experimentally determined electronic coupling increased from 12 cm-1 to 142 cm-1, and the reorganization energy increased from 2.3 to 3.1 eV. The rate and salt dependence of the proton transfer-gated ET reaction from N-quinol MADH to amicyanin is also changed by the M51A mutation. These changes in ET parameters and rates for the reactions with M51A amicyanin were similar to those caused by the P52G mutation and indicated that the ET reaction had become gated by a similar process, most likely a conformational rearrangement of the protein ET complex. The results of the M51K and M51L mutations also have consequences on the kinetic mechanism of regulation of the interprotein ET with effects that are intermediate between what is observed for the reaction of the native amicyanin and M51A amicyanin. These data indicate that the loss of the interactions involving Pro52 were primarily responsible for the change in Kd for P52G amicyanin, while the interactions involving the Met51 side chain are entirely responsible for the change in ET parameters and conversion of the true ET reaction of native amicyanin into a conformationally gated ET reaction. PMID:17824674

Ma, John K; Wang, Yongting; Carrell, Christopher J; Mathews, F Scott; Davidson, Victor L

2007-09-08

393

Improving plant drought, salt and freezing tolerance by gene transfer of a single stress-inducible transcription factor.  

PubMed

Plant productivity is greatly affected by environmental stresses such as drought, salt loading and freezing. We reported that a cis-acting promoter element, the dehydration response element (DRE), plays an important role in regulating gene expression in response to these stresses in Arabidopsis. The transcription factor DREB1A specifically interacts with the DRE and induces expression of stress tolerance genes. We show here that overexpression of the cDNA encoding DREB1A in transgenic Arabidopsis plants activated the expression of many of theses stress tolerance genes under normal growing conditions and resulted in improved tolerance to drought, salt loading and freezing. However, use of the strong constitutive 35S cauliflower mosaic virus (CaMV) promoter to drive expression of DREB1A also resulted in severe growth retardation under normal growing conditions. In contrast, expression of DREB1A from the stress-inducible rd29A promoter gave rise to minimal effects on plant growth while providing an even greater tolerance to stress conditions than did expression of the gene from the CaMV promoter. As the DRE-related regulatory element is not limited to Arabidopsis the DREB1A cDNA and the rd29A promoter may be useful for improving the stress tolerance of agriculturally important crops by gene transfer. PMID:11387979

Yamaguchi-Shinozaki, K; Shinozaki, K

2001-01-01

394

An inter-subspecies cloned buffalo (Bubalus bubalis) obtained by transferring of cryopreserved embryos via somatic cell nuclear transfer.  

PubMed

The aim of this study was to explore the feasibility of cryopreservation of inter-subspecies cloned embryos in buffalo. In our experiment, river buffalo ear fibroblast nucleus was fused into swamp buffalo oocyte cytoplasm. The blastocyst formation rate for nuclear transfer of freshly thawed cells was not different from those of growing cells, confluent or serum-starved cells. A total of 122 cloned blastocysts derived from cryopreserved fibroblasts were cryopreserved and thawed, 37 were survived, the cryosurvival rate was 30.3%. The survived blastocysts were transferred into 15 recipient buffalos. Five of the recipients established pregnancy, but four of them aborted on day 53, 59, 145 and 179 of gestation respectively. One cross-bred buffalo (Murrah × Swamp buffalo (2n = 49) received three embryos delivered a 40.5 kg female calf by natural delivery on day 320 of gestation. Up to now (13-month old), the cloned calf has been growing well with no abnormity observed. These results demonstrated that cryopreservation of inter-subspecies cloned embryos is feasible to produce buffalo offspring. PMID:19788521

Yang, B Z; Yang, C Y; Li, R C; Qin, G S; Zhang, X F; Pang, C Y; Chen, M T; Huang, F X; Li, Z; Zheng, H Y; Huang, Y J; Liang, X W

2010-10-01

395

[Study on the expression of nm23-M1/NDPK a during the blastocyst adhesiveness in the mouse endometrium].  

PubMed

The nm23 gene was originally identified as a metastasis suppressor gene by differential hybridization of non-metastatic and metastatic clones of murine K-1735 melanoma cell lines. Subsequently, other highly homologous genes were characterized and shown to code for nucleoside diphosphate kinase (NDPK) isotypes. These enzymes have been evidenced in a wide variety of organisms. In human, up to eight distinct but highly related genes have been discovered. The nm23-H1 and nm23-H2 gene products share 88% identity and are about 95% and 98% identical to the murine nm23-M1 and nm23-M2 proteins respectively. A number of data indicate that nm23 family, initially documented as metastasis suppressors in some cancer types, are involved in the control of normal development, differentiation and apoptosis. The trophoblast cells of blastocyst and of the normal first-trimester placenta share some phenotypic similarities with malignant cells, such as rapid proliferation and ability to invade neighbouring tissues, including basement membrane, during the process of implantation and placental development, but do not have the ability for unlimited growth or metastasis, as few trophoblast cells can be identified in the deciduas, and trophoblasts rarely penetrate the maternal blood vessels. Although some data indicate that nm23 family play an important role in regulation of reproductive processes, little is know about its actual mechanism. In our studies, we performed RT-PCR, Western blot and immunohistochemical analyses of nm23-M1/NDPK A expression during the blastocyst adhesiveness in the mouse endometrium. The nm23-M1 mRNA expression was shown progressive increase in D5 mice endometrium by RT-PCR, which was consistent with the result obtained by Western blot and immunohistochemistry. It is suggested that nm23-M1/NDPK A was involved in the process of blastocyst implantation. PMID:15511071

Pan, Wei; Wang, Ying Xiong; Li, Gang; Yang, Rong; He, Jun Lin; Liu, Xue Qing

2004-08-01

396

Efficient production of chimeric mice from embryonic stem cells injected into 4- to 8-cell and blastocyst embryos  

PubMed Central

Background Production of chimeric mice is a useful tool for the elucidation of gene function. After successful isolation of embryonic stem (ES) cell lines, there are many methods for producing chimeras, including co-culture with the embryos, microinjection of the ES cells into pre-implantation embryos, and use of tetraploid embryos to generate the full ES-derived transgenic mice. Here, we aimed to generate the transgenic ES cell line, compare the production efficiency of chimeric mice and its proportion to yield the male chimeric mice by microinjected ES cells into 4- to 8-cell and blastocysts embryos with the application of Piezo-Micromanipulator (PMM), and trace the fate of the injected ES cells. Results We successfully generated a transgenic ES cell line and proved that this cell line still maintained pluripotency. Although we achieved a satisfactory chimeric mice rate, there was no significant difference in the production of chimeric mice using the two different methods, but the proportion of the male chimeric mice in the 4- to 8-cell group was higher than in the blastocyst group. We also found that there was no tendency for ES cells to aggregate into the inner cell mass using in vitro culture of the chimeric embryos, indicating that they aggregated randomly. Conclusions These results showed that the PMM method is a convenient way to generate chimeric mice and microinjection of ES cells into 4- to 8-cell embryos can increase the chance of yielding male chimeras compared to the blastocyst injection. These results provide useful data in transgenic research mediated by ES cells.

2013-01-01

397

Effects of oocyte quality, semen donor and embryo co-culture system on the efficiency of blastocyst production in goats.  

PubMed

The aim of the study was to determine whether the selection of immature oocytes by a combination of cumulus-oocyte-complexes (COCs) morphology and staining with brilliant cresyl blue (BCB) would be helpful in selecting developmentally competent oocytes, and thereby increase the efficiency of blastocyst production from ovarian oocytes of FSH-primed, adult goats. In a second experiment the interaction between oocyte quality and semen donor was assessed. In a third experiment the usefulness of Vero cells for co-culture with goat embryos was investigated. In the pool of morphologically normal COCs recovered from ovaries following slicing (21.9+/-11.0), the mean rate of COCs classified as BCB+ was 85.6%, and the BCB- was approximately 11%. Oocytes classified as grade 1 and BCB+ exhibited the highest developmental competence (P<0.001) after in vitro maturation and fertilization compared with oocytes of grade 1 BCB- and grade 2 BCB+ or BCB-. There were no significant differences in developmental competence in grade 2 oocytes, regardless of BCB coloration. No significant differences in embryo cleavage and blastocyst formation rates among three bucks were observed when morphologically normal, BCB+ oocytes were used. For all tested bucks, differences in embryo production efficiency were related only to the oocyte quality. Similar blastocyst rates were developed from embryos co-cultured with goat oviduct epithelial cells (34.3%) and with Vero cells (33.3%). These results show that the most important criterion for selection of COCs before maturation is the visual assessment of morphological features. Staining with BCB of COCs recovered from adult goats does not enhance efficiency of selection of developmentally competent oocytes for IVF. PMID:17651793

Katska-Ksiazkiewicz, L; Opiela, J; Ry?ska, B

2007-07-24

398

Detection of charge transfer processes in Cr-doped SrTiO{sub 3} single crystals  

SciTech Connect

An insulator-to-metal transition is observed in Cr-doped SrTiO{sub 3} single crystals upon extended exposure to a high electric field, namely, electroconditioning (EC). Electron paramagnetic resonance (EPR) and transport measurements under laser irradiation show anticorrelation between the Cr{sup 3+} EPR signal and the electrical current. This proves that the Cr{sup 3+} ions are responsible for the photocurrent that initiates the EC process. We observe the presence of Cr{sup 3+}/Cr{sup 4+} mixed valencies in the bulk in the conducting state. The EPR characterization of the spectra in the conducting state excludes the possibility of a Cr{sup 3+}-oxygen vacancy complex in the bulk as a result of the EC.

La Mattina, F. [Physik-Institut der Universitaet Zuerich, Winterthurerstr. 190, CH-8057 Zuerich (Switzerland); IBM Research, Zurich Research Laboratory, Saeumerstr. 4, CH-8803 Rueschlikon (Switzerland); Bednorz, J. G.; Alvarado, S. F. [IBM Research, Zurich Research Laboratory, Saeumerstr. 4, CH-8803 Rueschlikon (Switzerland); Shengelaya, A. [Physics Institute of Tbilisi State University, Chavchavadze 3, GE-0128, Tbilisi (Georgia); Keller, H. [Physik-Institut der Universitaet Zuerich, Winterthurerstr. 190, CH-8057 Zuerich (Switzerland)

2008-07-14

399

Single-nucleotide polymorphism analysis using fluorescence resonance energy transfer between DNA-labeling fluorophore, fluorescein isothiocyanate, and DNA intercalator, POPO-3, on bacterial magnetic particles.  

PubMed

To develop an analytical system for single-nucleotide polymorphisms (SNPs), the fluorescence resonance energy transfer (FRET) technique was employed on a bacterial magnetic particle (BMP) surface. A combination of fluorescein isothiocyanate (FITC; excitation 490 nm/emission 520 nm) labeled at the 5' end of DNA and an intercalating compound (POPO-3, excitation 534 nm/emission 570 nm) was used to avoid the interference from light scattering caused by nanoparticles. After hybridization between target DNA immobilized onto BMPs and FITC-labeled probes, fluorescence from POPO-3, which was excited by the energy from the FITC, was detected. The major homozygous (ALDH2*1), heterozygous (ALDH2*1/*2), and minor homozygous (ALDH2*2) genotypes in the blood samples were discriminated by this method. The assay described herein allows for a simple and rapid SNP analysis using a fully automated system. PMID:12910548

Nakayama, Hideki; Arakaki, Atsushi; Maruyama, Kohei; Takeyama, Haruko; Matsunaga, Tadashi

2003-10-01

400

Model description for single-electron transfer in slow-ion--H sub 2 -molecule collisions: Studies for H sup + , He sup 2+ , and C sup 4+ projectiles  

SciTech Connect

We discuss a recently proposed model for describing single-electron transfer in slow- or intermediate-energy-ion--H{sub 2}-molecule collisions and present results for the examples of H{sup +}, He{sup 2+}, and C{sup 4+}-ion impact. The dynamics of the two active electrons is given by a one-electron potential model, within the framework of the semiclassical close-coupling description, in conjunction with conservation of the norm of the total two-electron wave function. Considerable numerical simplifications occur when the length of the molecular axis is set to zero. It is argued that this model description of ion-molecule collisions is both efficient and remarkably accurate.

Fritsch, W. (Bereich Schwerionenphysik, Hahn-Meitner-Institut Berlin, D-1000 Berlin 39 (Germany))

1992-10-01

401

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

402

Evaluation of the gauge factor for single-walled carbon nanonets on the flexible plastic substrates by nano-transfer-printing  

NASA Astrophysics Data System (ADS)

Nano-transfer-printing (nTP) is increasingly used for the micro-fabrication of nanoscale materials onto flexible plastic substrates. This paper reports a nTP process for single-walled carbon nanonets (SWCNNs) for use in strain sensors. Traditional SWCNNs grown on a silicon substrate by alcohol catalytic chemical vapor deposition (ACCVD) can serve as strain-sensing elements in strain sensors and nano-electromechanical system (NEMS) sensors, but ACCVD is not well suited to the task. To improve SWCNN fabrication, this work deposits a parylene-C thin film on SWCNNs for transfer-printing onto flexible plastic substrates with polyimide tape. Quantification of the fabricated SWCNN strain-sensing ability (gauge factor) is performed by comparing two specimens with different pattern features and substrates. The gauge factor is measured by tensile testing. SWCNN density variations relative to the observed gauge factors are discussed. Results show that SWCNN gauge factors range from 1.46 to 8.22, depending on the substrate and pattern width. It is further observed that the gauge factor of the presented SWCNN thin film increases when the width of the SWCNN decreases to the low micro-dimensions, i.e. below 40 µm, indicating a significant scaling factor.

Hsu, C. C.; Chao, R. M.; Liu, C. W.; Liang, Steven Y.

2011-07-01

403

Bionano donor-acceptor hybrids of porphyrin, ssDNA, and semiconductive single-wall carbon nanotubes for electron transfer via porphyrin excitation.  

PubMed

Photoinduced electron transfer in self-assemblies of porphyrins ion-paired with ssDNA wrapped around single-wall carbon nanotubes (SWCNTs) has been reported. To accomplish the three-component hybrids, two kinds of diameter-sorted semiconducting SWCNT(n,m)s of different diameter ((n,m) = (6,5) and (7,6)) and free-base or zinc porphyrin bearing peripheral positive charges ((TMPyP(+))M (tetrakis(4-N-methylpyridyl)porphyrin); M = Zn and H(2)) serving as light-absorbing photoactive materials are utilized. The donor-acceptor hybrids are held by ion-pairing between the negatively charged phosphate groups of ssDNA on the surface of the SWCNT and the positively charged at the ring periphery porphyrin macrocycle. The newly assembled bionano donor-acceptor hybrids have been characterized by transmission electron microscopy (TEM) and spectroscopic methods. Photoinduced electron transfer from the excited singlet porphyrin to the SWCNTs directly and/or via ssDNA as an electron mediator has been established by performing systematic studies involving the steady-state and time-resolved emission as well as the transient absorption studies. Higher charge-separation efficiency has been successfully demonstrated by the selection of the appropriate semiconductive SWCNTs with the right band gap, in addition to the aid of ssDNA as the electron mediator. PMID:22088093

D'Souza, Francis; Das, Sushanta K; Zandler, Melvin E; Sandanayaka, Atula S D; Ito, Osamu

2011-11-16

404