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1

Isolation, microinjection and transfer of mouse blastocysts.  

PubMed

Genetically modified mice by means of homologous recombination in embryonic stem (ES) cells are generated by injection of manipulated ES cells into recipient blastocysts. The injected blastocysts, following reintroduction into recipient foster mice, will produce chimeric mice in which the manipulated ES cells populate the germline and transmit the induced mutation to the offspring. Crossing of the chimeras' offspring bearing the targeted mutation in heterozygosis will ultimately produce mice homozygous for the specific genetic mutation. Here we describe the steps and procedures required to generate the chimeric mice leading to the transfer of a genetic mutation to the mouse germline. PMID:19266343

Reid, Susan W; Tessarollo, Lino

2009-01-01

2

Concomitant ovarian drilling and oocyte retrieval by laparoendoscopic single-site surgery led to live birth using in vitro maturation of oocyte and transfer of frozen-thawed blastocyst in woman with polycystic ovary syndrome.  

PubMed

This case report describes a case of concomitant ovarian drilling and retrieval of oocytes using laparoendoscopic single-site surgery and the resultant birth of a healthy infant after transfer of frozen-thawed blastocyst from in vitro matured oocyte in a woman with polycystic ovary syndrome. A 33-year-old woman presented with anovulatory, clomiphene-resistant polycystic ovary syndrome, and 1-year history of infertility. Thirty-seven immature oocytes were retrieved and multiperforation of ovaries was performed at the same time by laparoendoscopic single-site surgery. Twenty-three oocytes reached metaphase II after 24-h culture in in vitro maturation medium, which was followed by intracytoplasmic sperm injection. Eventually, seven embryos were vitrified and spontaneous ovulation was restored after the operation. Although the first single frozen-thawed blastocyst transferred in a natural cycle ended up a biochemical pregnancy, the second frozen-thawed blastocyst transfer resulted in successful pregnancy, followed by live birth of a healthy male infant. PMID:24754853

Hirata, Tetsuya; Fujimoto, Akihisa; Koga, Kaori; Wada-Hiraike, Osamu; Fujii, Tomoyuki; Osuga, Yutaka

2014-05-01

3

Effect of artificial shrinkage on clinical outcome in fresh blastocyst transfer cycles  

PubMed Central

Objective This study aimed to determine the safety and clinical effect of artificial shrinkage (AS) in terms of assisted hatching of fresh blastocysts. Also, we evaluated the correlation between patient age and the effect of AS on clinical outcome. Methods Two AS methods, using a 29-gauge needle and laser pulse, were compared. Seventy-three blastocysts were shrunk using a 29-gauge needle and the same number of other blastocysts were shrunk by a laser pulse. We evaluated the shrunken blastocysts hourly and considered them viable if they re-expanded >70%. Blastocyst transfer cycles (n=134) were divided into two groups: a control group consisted of the cycles whose intact embryos were transferred (n=100), while the AS group consisted of the cycles whose embryos were replaced following AS (n=34). The implantation and pregnancy rates of the control group and AS group were compared (p<0.05). Results The re-expansion rates of the 29-gauge needle and laser pulse AS groups were similar (56 [76.7%] vs. 62 [84.9%], respectively). All of the remaining shrunken blastocysts were re-expanded within 2 hours. There was no degeneration of shrunken blastocysts. The total and clinical pregnancy rate of the AS group (23 [67.6%]; 20 [58.8%], respectively) was significantly higher than that of the control group (47 [47.0%]; 39 [39.0%], respectively). In the older patient group, there was no difference in the clinical outcomes between the AS and control groups. Conclusion These results suggest that AS of blastocoele cavity, followed by the transfer, would be a useful approach to improve the clinical outcome in cycles in which fresh blastocyst stage embryos are transferred. PMID:22384424

Park, Jeong Hyun; Ryu, Eun Kyung; Yoon, Hae Jin; Yoon, San Hyun; Hur, Chang Young; Lee, Won Don; Lim, Jin Ho

2011-01-01

4

The developmental potential of the inner cell mass of blastocysts that were derived from mouse ES cells using nuclear transfer technology  

Microsoft Academic Search

The present study examined the causes of the low developmental potential of enucleated oocytes that have received ES cells and consequent postnatal death of the young. The inner cell masses (ICM) of nuclear-transferred blastocysts or diploid blastocysts were injected into tetraploid blastocysts (group B) or nuclear-transferred tetraploid blastocysts (group C), respectively. The developmental potential of these groups was compared with

T. Amano; Y. Kato; Y. Tsunoda

2002-01-01

5

Clinical outcome of fresh and vitrified-warmed blastocyst and cleavage-stage embryo transfers in ethnic Chinese ART patients  

PubMed Central

Objectives This study sought to evaluate the outcome of fresh and vitrified-warmed cleavage-stage and blastocyst-stage embryo transfers in patients undergoing ART treatment within an ethnic Chinese population. Study design We compared the clinical results of embryo transfer on the 3rd (cleavage stage) or 5th (blastocyst stage) day after oocyte retrieval, including clinical pregnancy rates, implantation rates and multiple pregnancy rates. Results Our data showed that blastocyst transfer on day 5 did not significantly increase clinical pregnancy rate (41.07% vs 47.08%, p>0.05) and implantation rate (31.8% vs 31.2%, p>0.05) in patients under 35 years of age, in comparison with day 3 cleavage stage embryo transfer. In patients older than 35 years of age, the clinical pregnancy rate after blastocyst transfer was slightly decreased compared with cleavage stage embryo transfer (33.33% vs 42.31%, p>0.05). Unexpectedly, It was found that vitrified-warmed blastocyst transfer resulted in significantly higher clinical pregnancy rate (56.8%) and implantation rate (47%) compared with fresh blastocyst transfer in controlled stimulation cycles (41.07% and 31.8%, respectively). For patients under 35 years of age, the cumulative clinical pregnancy rate combining fresh and vitrified-warmed blastocyst transfer cycles were significantly higher compared to just cleavage-stage embryo transfer (70.1% versus 51.8%, p<0.05). However, the cumulative multiple pregnancy rates showed no significant difference between the two groups. Conclusions In an ethnic Chinese patient population, fresh blastocyst transfer does not significantly increase clinical pregnancy rate. However, subsequent vitrified-warmed blastocyst transfer in a non-controlled ovarian hyperstimulation cycle dramatically improves clinical outcomes. Therefore, blastocyst culture in tandem with vitrified-warmed blastocyst transfer is recommended as a favourable and promising protocol in human ART treatment, particularly for ethnic Chinese patients. PMID:23039212

2012-01-01

6

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

Microsoft Academic Search

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

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

1999-01-01

7

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

Microsoft Academic Search

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

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

1999-01-01

8

Endometrial thickness, Caucasian ethnicity, and age predict clinical pregnancy following fresh blastocyst embryo transfer: a retrospective cohort  

Microsoft Academic Search

BACKGROUND: In-vitro fertilization (IVF) with blastocyst as opposed to cleavage stage embryos has been advocated to improve success rates. Limited information exists on which to predict which patients undergoing blastocyst embryo transfer (BET) will achieve pregnancy. This study's objective was to evaluate the predictive value of patient and cycle characteristics for clinical pregnancy following fresh BET. METHODS: This was a

Michael L Traub; Anne Van Arsdale; Lubna Pal; Sangita Jindal; Nanette Santoro

2009-01-01

9

Monochorionic triamniotic triplets following conventional in vitro fertilization and blastocyst transfer  

PubMed Central

Multiple pregnancy in in vitro fertilization (IVF) is on the decline with a reduction in number of embryos transferred. But the risk of monozygotic splitting persists. The risk of monozygotic twinning in women undergoing IVF is reported to be twice that of natural conception, and monochorionic triplets are even rarer at 100 times more than natural conception. We report a case of monochorionic triamniotic (MCTA) triplets following conventional IVF and blastocyst transfer without zona manipulation. This report highlights the possibility of zygotic splitting in IVF in young couples with no family history, in centers with good experience with blastocyst transfer. MCTA triplets carry a high risk of perinatal mortality and morbidity and need multidisciplinary care. Prevention and prediction of zygotic splitting ought to be realized with better reporting and identification of possible risk factors.

Gurunath, Sumana; Makam, Adinarayana; Vinekar, Sriprada; Biliangady, Reeta H.

2015-01-01

10

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. PMID:23937723

2013-01-01

11

Blastocyst development after intergeneric nuclear transfer of mountain bongo antelope somatic cells into bovine oocytes.  

PubMed

Intergeneric embryos were constructed by nuclear transfer using Mountain Bongo antelope somatic cells fused with enucleated bovine oocytes and their subsequent development in vitro was investigated. After two to six passages, starved or non-starved skin fibroblast cells were used as donor nuclei. In vitro matured bovine oocytes were enucleated by squeezing the first polar body and surrounding cytoplasm through a slit in the zona pellucida. After injection of a somatic cell into the perivitelline space, couplets were fused electrically and activated chemically, then subjected to different embryo culture treatments. Serum starvation had no effect on the frequency of cleavage to two cells or on development to the blastocyst stage in either sequential hamster embryo culture medium (HECM)-6/TCM-199 + serum or HECM-9/TC-199 + serum, or modified synthetic oviduct fluid (mSOF) culture medium. When couplets from non-starved donor nuclei were cultured, the frequency of cleavage (66 +/- 8% vs. 44 +/- 5%), development to >/=9 cells (46 +/- 6% vs. 24 +/- 4%), and formation of blastocysts (24 +/- 5% vs. 11 +/- 2%) were all significantly higher (p < 0.05) in the HECM-6 medium than in mSOF medium. In conclusion, bovine oocytes can support blastocyst development after intergeneric fusion with bongo fibroblasts. This technique could potentially be used as an alternative to using scarce bongo oocytes in attempts to propagate these endangered animals. PMID:12713698

Lee, Byeongchun; Wirtu, Gemechu G; Damiani, Philip; Pope, Earle; Dresser, Betsy L; Hwang, Woosuk; Bavister, Barry D

2003-01-01

12

Efficient cryopreservation of bovine blastocysts derived from nuclear transfer with somatic cells using partial dehydration and vitrification.  

PubMed

Preservation by vitrification of Day 7 and Day 8 bovine blastocysts derived from nuclear transfer with cumulus cells was compared with preservation of in vitro fertilized blastocysts. In Experiment 1, embryos were vitrified in PBS containing 60% ethylene glycol. In Experiment 2, they were vitrified in combination with partial dehydration using a solution of 39% ethylene glycol + 0.7 M sucrose and 8.6% Ficoll. In Experiment 1, survival and hatching rates were 44 and 95% for nuclear transferred embryos, and 78 and 55% for in vitro fertilized embryos, respectively. In Experiment 2, survival and hatching rates were 93 and 95% for nuclear transfer embryos, and 77 and 85% for in vitro fertilized embryos, respectively. It is concluded that Day 7 and Day 8 bovine blastocysts derived from cumulus cells could be cryopreserved without the loss of viability by a simple and efficient method using a combination of partial dehydration and vitrification. PMID:10898213

Nguyen, B X; Sotomaru, Y; Tani, T; Kato, Y; Tsunoda, Y

2000-04-15

13

Cross-validation and predictive value of near-infrared spectroscopy algorithms for day-5 blastocyst transfer.  

PubMed

Near-infrared (NIR) spectroscopic metabolomic profiling of spent embryo-culture media has been used to calculate a viability score for individual embryos. These scores have been found to correlate to the reproductive potential of cleavage-stage embryos. In this study, 137 spent blastocyst media samples were collected after single-embryo transfer and analysed by NIR spectroscopy to generate an algorithm and calculate viability scores. To blindly validate the algorithm development process, another algorithm was trained on 47 preselected samples from clinic 1 and then used to predict the outcome of 42 samples from clinic 2. The overall pregnancy rate from the two clinical sites was 50.4%. A positive correlation (R(2)=0.82, P=0.03) was observed with the increasing viability score quintiles and their associated implantation rates. Cross-validation of an algorithm generated from NIR analysis of media samples at one clinical setting blindly was shown to predict implantation potential of blastocysts cultured at another clinic in a different culture media and culture volume. This study demonstrates that metabolomic profiling by NIR spectroscopic analysis of day-5 spent embryo-culture media can predict the implantation potential of blastocysts. Furthermore, this method may not be restricted to a specific set of culturing conditions. The successes of IVF treatment cycles are in part limited by the ability to select the best single embryo from a cohort of patient embryos for transfer back to the woman. Routine procedures of embryo selection are based on morphology, including cell number and size, and the timing of cell division. These methods are favoured because they are quick and easy to assess. Human embryos are grown in culture solutions, which are specific for their stage of development. Recent studies analysing the culture solution in which the embryo are grown, by near infrared (NIR) spectroscopic analysis, have been able to predict if an embryo will implant or not. As culture conditions often vary between IVF laboratories the questions remained if the NIR technique could be used to independently predict the implantation potential of an embryo cultured at one laboratory using an algorithm trained on embryos at a second clinic, a so-called cross-validation. The results of this study show that NIR spectroscopy can predict the ability of embryos to implant even when grown in different IVF laboratories and in two different culture solutions. This information supports the idea that NIR spectroscopy can be used globally not relying on specific culture conditions or media. PMID:21397559

Ahlström, Aisling; Wikland, Matts; Rogberg, Lena; Barnett, Jeannette Siques; Tucker, Michael; Hardarson, Thorir

2011-05-01

14

Massage therapy improves in vitro fertilization outcome in patients undergoing blastocyst transfer in a cryo-cycle.  

PubMed

Context • Massage therapy is increasingly used to relieve physical and mental discomfort and is suggested as a safe therapeutic modality, without any significant risks or any known side effects. Although a multitude of complementary therapies, such as acupuncture, are applied in reproductive medicine, no information is available with regard to the application of massage as an adjuvant therapy in assisted-reproduction techniques (ARTs). Objectives • This study was intended to assess the effectiveness of a deep relaxation (andullation) therapy based on oscillating vibrations when used prior to embryo transfer (ET) in in vitro fertilization (IVF) cryo-cycles. Design • The research team designed a retrospective, observational study. Participants willing to undergo the massage treatment were allocated to the intervention (andullation) group. Setting • The study was performed at the IVF Centers Prof. Zech-Bregenz in Bregenz, Austria. Participants • A total of 267 IVF patients, with a mean age of 36.3 y, participated in this single-center study. Intervention • All patients receiving a transfer of vitrified and warmed blastocysts between January and December 2012 were included in the evaluation. Prior to ET, the andullation group received a standardized program of therapy-a 30-min, deep relaxation massage on an oscillating (vibrating) device, whereas the control group did not. Outcome Measures • To determine efficacy, the primary outcomes that the study measured were (1) pregnancy rates (PRs), by testing urine and obtaining a positive ?-human chorionic gonadotropin (?-hCG); and (2) ongoing, pregnancies (oPR), by observation of fetal heartbeat and birth rates (BR) as well as miscarriage rates. The patients' medical histories and types of infertility as well as the quality of the embryo transfers (ETs) were evaluated. Results • In patients using the massage therapy prior to ET, significantly higher PRs, oPRs, and BRs were observed compared with the control group-PR: 58.9% vs 41.7%, P < .05; oPR: 53.6% vs 33.2%, P < .01; and BR: 32.0% vs 20.3%, P < .05. No differences were detected among groups for patients' ages, hormonal substitution protocols, endometrium structures and buildups, quality of transferred embryos, or quality of transfers. No adverse effects were noted in the massage group. Conclusions • The research team's results suggested that andullation therapy prior to blastocyst transfer in a cryo-cycle improves embryo implantation, most likely due to a reduction in stress (ie, a relaxation effect on patients), a reduction in uterine contractions, and, probably, an enhancement of the blood flow in the abdominal region. These findings provide support for use of andullation as a complementary therapy for ART. PMID:25830275

Okhowat, Jasmin; Murtinger, Maximilian; Schuff, Maximilian; Wogatzky, Johannes; Spitzer, Dietmar; Vanderzwalmen, Pierre; Wirleitner, Barbara; Zech, Nicolas Herbert

2015-03-01

15

A single blastocyst assay optimized for detecting CRISPR/Cas9 system-induced indel mutations in mice  

PubMed Central

Background Microinjection of clustered regulatory interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9)-related RNA and DNA into fertilized eggs is a novel approach for creating gene-modified mice. Blastocysts obtained just before implantation may be appropriate for testing the fidelity of CRIPSR/Cas9-mediated genome editing because they can be individually handled in vitro and obtained 3 days after microinjection, thus allowing researchers to check mutations rapidly. However, it is not known whether indel mutations caused by the CRISPR/Cas9 system can be reproducibly detected in embryos. In this study, we assessed the detection of CRISPR/Cas9-induced mutations in embryos. Results T7 endonuclease I was more effective than Surveyor nuclease for detecting mutations in annealed fragments derived from 2 plasmids, which contained nearly identical sequences. Mouse fertilized eggs were microinjected with CRISPR/Cas9-related RNA/DNA to examine whether non-homologous end joining-mediated knockout and homologous recombination-mediated knockin occurred in the endogenous receptor (G protein-coupled) activity modifying protein 2 (Ramp2) gene. Individual blastocysts were lysed to obtain crude DNA solutions, which were used for polymerase chain reaction (PCR) assays. T7 endonuclease I-based PCR and sequencing analysis demonstrated that 25–100% of the embryos were knockout embryos and 7–57% of the embryos were knockin embryos. Our results also established that crude DNA from a single blastocyst was an appropriate template for Whole genome amplification and subsequent assessment by PCR and the T7 endonuclease I-based assay. Conclusions The single blastocyst-based assay was useful for determining whether CRISPR/Cas9-mediated genome editing worked in murine embryos. PMID:25042988

2014-01-01

16

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

PubMed Central

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

2011-01-01

17

Effect of Sperm DNA Fragmentation on Clinical Outcome of Frozen-Thawed Embryo Transfer and on Blastocyst Formation  

PubMed Central

During the last decades, many studies have shown the possible influence of sperm DNA fragmentation on assisted reproductive technique outcomes. However, little is known about the impact of sperm DNA fragmentation on the clinical outcome of frozen-thawed embryo transfer (FET) from cycles of conventional in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI). In the present study, the relationship between sperm DNA fragmentation (SDF) and FET clinical outcomes in IVF and ICSI cycles was analyzed. A total of 1082 FET cycles with cleavage stage embryos (C-FET) (855 from IVF and 227 from ICSI) and 653 frozen-thawed blastocyst transfer cycles (B-FET) (525 from IVF and 128 from ICSI) were included. There was no significant change in clinical pregnancy, biochemical pregnancy and miscarriage rates in the group with a SDF >30% compared with the group with a SDF ?30% in IVF and ICSI cycles with C-FET or B-FET. Also, there was no significant impact on the FET clinic outcome in IVF and ICSI when different values of SDF (such as 10%, 20%, 25%, 35%, and 40%) were taken as proposed threshold levels. However, the blastulation rates were significantly higher in the SDF ?30% group in ICSI cycle. Taken together, our data show that sperm DNA fragmentation measured by Sperm Chromatin Dispersion (SCD) test is not associated with clinical outcome of FET in IVF and ICSI. Nonetheless, SDF is related to the blastocyst formation in ICSI cycles. PMID:24733108

Ni, Wuhua; Xiao, Shiquan; Qiu, Xiufang; Jin, Jianyuan; Pan, Chengshuang; Li, Yan; Fei, Qianjin; Yang, Xu; Zhang, Liya; Huang, Xuefeng

2014-01-01

18

Effect of sperm DNA fragmentation on clinical outcome of frozen-thawed embryo transfer and on blastocyst formation.  

PubMed

During the last decades, many studies have shown the possible influence of sperm DNA fragmentation on assisted reproductive technique outcomes. However, little is known about the impact of sperm DNA fragmentation on the clinical outcome of frozen-thawed embryo transfer (FET) from cycles of conventional in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI). In the present study, the relationship between sperm DNA fragmentation (SDF) and FET clinical outcomes in IVF and ICSI cycles was analyzed. A total of 1082 FET cycles with cleavage stage embryos (C-FET) (855 from IVF and 227 from ICSI) and 653 frozen-thawed blastocyst transfer cycles (B-FET) (525 from IVF and 128 from ICSI) were included. There was no significant change in clinical pregnancy, biochemical pregnancy and miscarriage rates in the group with a SDF >30% compared with the group with a SDF ?30% in IVF and ICSI cycles with C-FET or B-FET. Also, there was no significant impact on the FET clinic outcome in IVF and ICSI when different values of SDF (such as 10%, 20%, 25%, 35%, and 40%) were taken as proposed threshold levels. However, the blastulation rates were significantly higher in the SDF ?30% group in ICSI cycle. Taken together, our data show that sperm DNA fragmentation measured by Sperm Chromatin Dispersion (SCD) test is not associated with clinical outcome of FET in IVF and ICSI. Nonetheless, SDF is related to the blastocyst formation in ICSI cycles. PMID:24733108

Ni, Wuhua; Xiao, Shiquan; Qiu, Xiufang; Jin, Jianyuan; Pan, Chengshuang; Li, Yan; Fei, Qianjin; Yang, Xu; Zhang, Liya; Huang, Xuefeng

2014-01-01

19

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

PubMed

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

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

2013-10-01

20

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

PubMed Central

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

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

2014-01-01

21

Generation of SV40-transformed rabbit tracheal-epithelial-cell-derived blastocyst by somatic cell nuclear transfer  

PubMed Central

The prospect of developing large animal models for the study of inherited diseases, such as cystic fibrosis (CF), through somatic cell nuclear transfer (SCNT) has opened up new opportunities for enhancing our understanding of disease pathology and for identifying new therapies. Thus, the development of species-specific in vitro cell systems that will provide broader insight into organ- and cell-type-specific functions relevant to the pathology of the disease is crucial. Studies have been undertaken to establish transformed rabbit airway epithelial cell lines that display differentiated features characteristic of the primary airway epithelium. This study describes the successful establishment and characterization of two SV40-transformed rabbit tracheal epithelial cell lines. These cell lines, 5RTEo- and 9RTEo-, express the CF transmembrane conductance regulator (CFTR) gene, retain epithelial-specific differentiated morphology and show CFTR-based cAMP-dependent Cl? ion transport across the apical membrane of a confluent monolayer. Immunocytochemical analysis indicates the presence of airway cytokeratins and tight-junction proteins in the 9RTEo- cell line after multiple generations. However, the tight junctions appear to diminish in their efficacy in both cell lines after at least 100 generations. Initial SCNT studies with the 9RTEo- cells have revealed that SV40-transformed rabbit airway epithelial donor cells can be used to generate blastocysts. These cell systems provide valuable models for studying the developmental and metabolic modulation of CFTR gene expression and rabbit airway epithelial cell biology. PMID:22234514

de Semir, D.; Maurisse, R.; Du, F.; Xu, J.; Yang, X.; Illek, B.; Gruenert, D. C.

2013-01-01

22

Development of Human Cloned Blastocysts Following Somatic Cell Nuclear Transfer with Adult Fibroblasts  

Microsoft Academic Search

Nuclear transfer stem cells (NTSC) holds considerable promise in the field of regenerative medicine and cell- based drug discovery. In this study, a total of 29 oocytes were obtained from three young (20-24 y) reproductive egg donors who had been successful in previous cycles. These oocytes, deemed by intended parents to be in excess of their reproductive needs, were donated

Andrew J. French; Catharine A. Adams; Linda S. Anderson; John R. Kitchen; Marcus R. Hughes; Samuel H. Wood

2008-01-01

23

Transfer of sexed caprine blastocysts freshly collected or derived from cultured morulae  

Microsoft Academic Search

This paper describes a simplified method for biopsying goat embryos for sex determination, followed by the transfer of these embryos to recipient does. A 90° angle holding pipet is described, which permits holding the embryo in position and, with minimal effort, open the zona pellucida and excise 5–10 trophoblast cells with the aid of a microsurgical blade. Twenty-four embryos were

M. El-Gayar; W. Holtz

2005-01-01

24

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

PubMed Central

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

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

2014-01-01

25

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

26

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

PubMed

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

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

2007-02-01

27

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...

28

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

PubMed Central

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

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

2014-01-01

29

Sibling embryo blastocyst development correlates with the in vitro fertilization day 3 embryo transfer pregnancy rate in patients under age 40  

Microsoft Academic Search

Objective: To examine the IVF day 3-ET pregnancy rate in patients under 40 with sibling embryo blastocyst development, compared with similar patients without blastocyst formation.Design: Retrospective analysis.Setting: Academic infertility center.Patient(s): One hundred twenty-five IVF day 3-ET patients under 40 with sibling embryos for extended culture.Intervention(s): Extended culture of nontransferred sibling embryos for blastocyst development.Main Outcome Measure(s): Pregnancy and multiple gestation

Jeffrey D Fisch; Amin A Milki; Barry Behr

1999-01-01

30

Successful Same-Cycle Blastocyst Transfer following Laparoscopic Ovarian Detorsion: A Report of Two Cases and Literature Review  

PubMed Central

Ovarian stimulation increases the risk of ovarian torsion. During an in vitro fertilization (IVF) cycle, the effects of ovarian torsion on retrieved oocytes and subsequent pregnancy chances are not clear. Moreover, no cases of ovarian torsion occurring following oocyte retrieval but prior to same-cycle embryo transfer have been reported. Such cases present a clinical dilemma with respect to optimal timing of embryo transfer. We report two cases of a 41-year-old and a 32-year-old infertility patients undergoing IVF who were diagnosed with ovarian torsion within several days following oocyte retrieval. Both patients were treated by early laparoscopic evaluation and detorsion followed by day five embryo transfer, resulting in successful pregnancies. Therefore, after prompt laparoscopic ovarian untwisting of a torsed ovary following egg retrieval, embryo transfer may be performed as originally scheduled during the concurrent cycle leading to favorable pregnancy outcomes. PMID:24864219

Seifer, David B.; Grazi, Richard V.

2014-01-01

31

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

PubMed

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

Theodorou, Efstathios; Forman, Robert

2012-10-01

32

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

PubMed

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

Sakurai, Masahiro; Suzuki, Chie; Yoshioka, Koji

2015-03-01

33

Storage in vivo of (/sup 3/H)prostaglandins by rabbit blastocysts  

SciTech Connect

Day 6 rabbit blastocysts that had previously been incubated with 10 nM (/sup 3/H)prostaglandin E2 (PGE2), (/sup 3/H) PGF2 alpha, or 0.5 microCi (/sup 3/H)water were surgically transferred to the uteri of day 6 pseudopregnant recipient rabbits. At 1, 3, and 20 h after transfer, blastocysts were collected from the recipient rabbits and evaluated for retention of (/sup 3/H)ligands. The transferred day 6 blastocysts were able to retain a significant proportion of the initial PGs for up to 20 h in vivo. These PGs were not metabolized while they remained in the blastocysts in vivo, as assessed by HPLC. The transferred blastocysts appeared normal and viable after 20 h in vivo, since implantation sites could be detected visually. These data support our hypothesis that blastocysts can sequester PGs from their environment in vivo and retain them unmetabolized during the critical period just before implantation.

Jones, M.A.; Anderson, W.; Turner, T.G.; Harper, M.J.

1985-03-01

34

Effect of the size of zona pellucida opening by laser assisted hatching on clinical outcome of frozen cleaved embryos that were cultured to blastocyst after thawing in women with multiple implantation failures of embryo transfer: a retrospective study  

PubMed Central

Purpose To evaluate the effect of the size of zona pellucida opening by laser assisted hatching for frozen cleaved embryo that were thawed after both fresh and frozen cleaved embryo transfer cycles failed and were cultured to blastocyst after thawing in patients with multiple implantation failures. Materials and methods Of 101 consecutive procedures (October 2003 to June 2006), 30 patients declined to perform assisted hatching and were selected as control group, 40 patients had 40 ?m opening of the zona (October 2003 to January 2005), 31 patients had 50% of the zona opening (February 2005 to June 2006). Results The pregnancy, implantation and delivery rates were significantly higher in 50% opening group (74%, 52% and 65%) compared to control group (17%, 10% and 13%; P?transfer. PMID:18365308

Fuchiwaki, Megumi; Hiraoka, Kaori; Horiuchi, Toshitaka; Murakami, Tomoyo; Kinutani, Masayuki; Kinutani, Kazuo

2008-01-01

35

Analysis of development-related gene expression in cloned bovine blastocysts with different developmental potential.  

PubMed

The high incidence of abnormalities in cloned calves is a most serious problem for bovine somatic cell nuclear transfer (NT) technology. Because there is little information on the differences in mRNA expression in cloned blastocysts with donor cells of different sex and origin, we compared development-related gene expression in two types of cloned bovine blastocysts with different potentials to develop into normal calves, a female adult cumulus cell line (high potential to develop into live calves) and a male fibroblast cell line (low potential to develop into live calves) to examine the correlation between the normality of cloned calves and blastocyst mRNA expression patterns. We analyzed 12 genes involved in apoptosis, growth factor signaling, metabolism, and DNA methylation in blastocysts originating from two types of donor cells and in vitro-fertilized blastocysts using quantitative real-time polymerase chain reaction. Expression of the pro-apoptotic Bax gene and anti-apoptotic Bcl-2 and Glut-1 genes in fibroblast-derived blastocysts was significantly higher than in cumulus cell-derived and in vitro-fertilized blastocysts. The high Bcl-2 and Glut-1 gene expression suggests that some embryonic cells with damaged DNA in fibroblast-derived blastocysts are not removed, and their descendants later manifest abnormal placenta or fetus formation. Transfer of pre-selected cloned blastocysts into recipients is required, however, to determine whether the expression pattern of these apoptosis-related genes reflects differences in the potential to develop into normal calves. PMID:16571076

Li, Xiangping; Amarnath, Dasari; Kato, Yoko; Tsunoda, Yukio

2006-01-01

36

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

37

Culture of viable human blastocysts in defined sequential serum-free media.  

PubMed

In human in-vitro fertilization (IVF), embryos are routinely transferred to the uterus on either day 2 or day 3 of development, resulting in a 10-15% implantation rate. However, in other mammalian species, the transfer of cleavage stage embryos, which normally reside in the oviduct, to the uterus results in a significantly lower implantation rate compared with blastocysts. It is therefore proposed that, in order to increase implantation rates in human IVF, one has to move to extended culture and transfer at the blastocyst stage. The transfer of blastocysts will not only help synchronize the embryo with the female tract but will facilitate the identification of those embryos with little or no developmental potential. In order to culture viable blastocysts it is important to use more than one culture medium to cater for the changing requirements of the preimplantation embryo as it develops and differentiates. If sequential culture media are not used, one can obtain blastocysts but their resultant viability is low. The use of sequential serum-free media in human IVF has resulted in > 50% of embryos becoming blastocysts with an implantation rate of approximately 50%. Further advances in human embryo culture should come from the replacement of protein with the glycosaminoglycan hyaluronate, which is more suitable than albumin in supporting implantation in the mouse, and which will eliminate biological variation and possible contamination from blood products. With the routine culture of human blastocysts will come the introduction of non-invasive tests of embryo viability, capable of identifying those blastocysts most likely to develop from a given cohort. As the implantation rate of blastocysts is higher than that of the cleavage stage embryo, fewer embryos will be required for transfer in order to establish a successful pregnancy, thereby reducing the number of multiple gestations and increasing the overall efficiency of human IVF. PMID:9755421

Gardner, D K; Lane, M

1998-06-01

38

Dihydrolipoic Acid Induces Cytotoxicity in Mouse Blastocysts through Apoptosis Processes  

PubMed Central

?-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). In view of the recent application of DHLA as a hydrophilic nanomaterial preparation, determination of its biosafety profile is essential. In the current study, we examined the cytotoxic effects of DHLA on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, in vivo implantation by embryo transfer, and early embryonic development in an animal model. Blastocysts treated with 50 ?M DHLA exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with DHLA were lower than that of their control counterparts. Moreover, in vitro treatment with 50 ?M DHLA was associated with increased resorption of post-implantation embryos and decreased fetal weight. Data obtained using an in vivo mouse model further disclosed that consumption of drinking water containing 100 ?M DHLA led to decreased early embryo development, specifically, inhibition of development to the blastocyst stage. However, it appears that concentrations of DHLA lower than 50 ?M do not exert a hazardous effect on embryonic development. Our results collectively indicate that in vitro and in vivo exposure to concentrations of DHLA higher than 50 ?M DHLA induces apoptosis and retards early pre- and post-implantation development, and support the potential of DHLA to induce embryonic cytotoxicity. PMID:22489194

Houng, Wei-Li; Lin, Cheng-An J.; Shen, Ji-Lin; Yeh, Hung-I; Wang, Hsueh-Hsiao; Chang, Walter H.; Chan, Wen-Hsiung

2012-01-01

39

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

40

Single-Molecule Fluorescence Resonance Energy Transfer  

Microsoft Academic Search

Fluorescent resonance energy transfer (FRET) is a powerful technique for studying conformational distribution and dynamics of biological molecules. Some conformational changes are difficult to synchronize or too rare to detect using ensemble FRET. FRET, detected at the single-molecule level, opens up new opportunities to probe the detailed kinetics of structural changes without the need for synchronization. Here, we discuss practical

Taekjip Ha

2001-01-01

41

Establishment of a pig fibroblast-derived cell line for locus-directed transgene expression in cell cultures and blastocysts.  

PubMed

We report the establishment of a spontaneously immortalized pig cell line designated Pig Flip-in Visualize (PFV) for locus-directed transgene expression in pig cells and blastocysts. The PFV cell line was isolated from pig ear fibroblasts transfected with a Sleeping Beauty DNA transposon-based docking vector harbouring a selection gene, an eGFP reporter gene, and an Flp recombinase site for locus-directed gene insertion. PFV cells have insertion of a single docking vector with stable eGFP expression and generated phenotypic normal blastocysts with transgene expression after somatic cell nuclear transfer. PFV cells supported Flp mediated cassette exchange for transgene substitution of eGFP with dsRED, and the dsRED transgenic PFV cells generated blastocysts with transgene expression. Hence, the PFV cell line constitutes a valuable pig equivalent to transformed cell lines from other mammalian species suitable for locus-directed transgene expression in cell cultures and, in addition, for transgene analyses in the very early embryonic stages. PMID:20336379

Jakobsen, Jannik E; Li, Juan; Moldt, Brian; Kragh, Peter M; Callesen, Henrik; Hertz, Jens Michael; Bolund, Lars; Jørgensen, Arne Lund; Mikkelsen, Jacob Giehm; Nielsen, Anders Lade

2011-01-01

42

Analysis of DNA fragmentation of in vitro cultured bovine blastocysts using TUNEL  

Microsoft Academic Search

Programmed cell death (apoptosis) characteristically affects the single cells of blastocysts whereas necrosis affects cluster of cells in both the inner cell mass (ICM) and the trophectoderm (TE). This study uses the trophectodermrminal deoxynucleotidyl transferase (TdT) mediated dUTP nick-end labeling (TUNEL) assay as a way of evaluating the proportion of apoptotic cells and, thus, bovine blastocyst quality during in vitro

E Neuber; C. M Luetjens; A. W. S Chan; G. P Schatten

2002-01-01

43

Can repeated IVF-ICSI-cycles be avoided by using blastocysts developing from poor-quality cleavage stage embryos?  

PubMed

In many clinics, good-quality embryos are selected for embryo transfer and cryopreservation at the cleavage stage, and poor-quality embryos are discarded. The aim of this retrospective study was to examine how many repeated IVF cycles could be avoided by culturing the cleavage stage poor-quality embryos to blastocyst stage and transferring them after vitrification and warming (604 IVF and intracytoplasmic sperm injection [IVF-ICSI] cycles were included). Poor-quality cleavage stage embryos not eligible for transfer or cryopreservation were cultured until day 5 or 6, and those developing to the blastocyst stage were vitrified. The rate of vitrified blastocysts and clinical pregnancy and delivery rate of the warmed blastocysts was evaluated. The effect of the extended culture on the cumulative delivery rate, and the number of avoided new treatment cycles was calculated. The surplus blastocysts resulted in clinical pregnancy, spontaneous abortion and delivery rates of 24.6%, 27.3% and 17.2% respectively. The use of surplus blastocysts raised cumulative delivery rate from 43% to 47% and 53 repeated new cycles were avoided. This study shows that the cumulative delivery rate can be increased, and repeated IVF-ICSI treatments avoided by using blastocysts developing from poor-quality cleavage stage embryos, which otherwise would have been discarded. PMID:25596905

Kaartinen, Noora; Das, Pia; Kananen, Kirsi; Huhtala, Heini; Tinkanen, Helena

2015-03-01

44

Effect of Vitrification on the MicroRNA Transcriptome in Mouse Blastocysts  

PubMed Central

Vitrification is commonly used in the cryopreservation of mammalian blastocysts to overcome the temporal and spatial limitations of embryo transfer. Previous studies have shown that the implantation ability of vitrified blastocysts is impaired and that microRNAs (miRNAs) regulate the critical genes for embryo implantation. However, little information is available about the effect of vitrification on the miRNA transcriptome in blastocysts. In the present study, the miRNA transcriptomes in fresh and vitrified mouse blastocysts were analyzed by miRNA Taqman assay based method, and the results were validated using quantitative real-time PCR (qRT-PCR). Then, the differentially expressed miRNAs were assessed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Overall, 760 known mouse miRNAs were detected in the vitrified and fresh mouse blastocysts. Of these, the expression levels of five miRNAs differed significantly: in the vitrified blastocysts, four miRNAs (mmu-miR-199a-5p, mmu-miR-329-3p, mmu-miR-136-5p and mmu-miR-16-1-3p) were upregulated, and one (mmu-miR-212-3p) was downregulated. The expression levels of all miRNAs measured by the miRNA Taqman assay based method and qRT-PCR were consistent. The four upregulated miRNAs were predicted to regulate 877 candidate target genes, and the downregulated miRNA was predicted to regulate 231 genes. The biological analysis further showed that the differentially expressed miRNAs mainly regulated the implantation of embryos. In conclusion, the results of our study showed that vitrification significantly altered the miRNA transcriptome in mouse blastocysts, which may decrease the implantation potential of vitrified blastocysts. PMID:25853900

Zhao, Xueming; Hao, Haisheng; Du, Weihua; Zhu, Huabin

2015-01-01

45

Pig blastocyst-uterine interactions.  

PubMed

The litter-bearing pig is an invaluable model for research in reproductive biology. Spherical pig blastocysts on Day 10 of pregnancy undergo rapid morphological changes to tubular and then filamentous forms by Day 12 and a filamentous conceptus of almost 1m in length by Day 16 of pregnancy. Thus, trophectoderm of each conceptus achieves intimate contact with luminal uterine epithelium (LE) for exchange of nutrients, gases, hormones, growth factors and other key molecules for survival and development. Estrogens secreted between Days 11 and 13 of pregnancy signals pregnancy recognition to ensure that nutrients and prostaglandin F2-alpha (PGF) are secreted into the uterine lumen (exocrine secretion) rather than into the uterine vein (endocrine secretion) which would lead to regression of the corpora lutea (CL) and failure to maintain pregnancy. Pigs have a true epitheliochorial placenta. The fluid filled amnion bouys the embryo so that it develops symmetrically. The allantois fills with allantoic fluid to expand contact of the chorioallantois with uterine LE, and the allanotois supports the vascular system of the placenta. The chorion/trophectoderm in direct contact with uterine LE exchanges gases and nutrients and forms unique structures call areolae that absorb nutrient-rich secretions from uterine glands and transports them directly into fetal blood. The period from Days 20 to 70 of pregnancy is for placental growth in preparation for rapid fetal growth between Days 70 and 114 (term) of gestation. Maturation of the fetal hypothalamic-pituitary-adrenal axis leads to increases in secretion of cortisol from the fetal adrenal glands. Cortisol sets in motion secretion of estrogens, oxytocin, relaxin and prolactin, as well as increases in their receptors, which are required for delivery of piglets and for initiation of lactation and expression of maternal behavior. This review provides details of gestation in the pig with respect to uterine biology, implantation, placentation, fetal development and parturition. PMID:24388881

Bazer, Fuller W; Johnson, Gregory A

2014-01-01

46

Progesterone replacement with vaginal gel versus i.m. injection: cycle and pregnancy outcomes in IVF patients receiving vitrified blastocysts  

PubMed Central

STUDY QUESTION Does the type of luteal support affect pregnancy outcomes in recipients of vitrified blastocysts? SUMMARY ANSWER Luteal support with vaginal progesterone gel or i.m. progesterone (IMP) results in comparable implantation and pregnancy rates in IVF patients receiving vitrified blastocysts. WHAT IS KNOWN ALREADY In fresh IVF cycles, both IMP and vaginal progesterone have become the standard of care for luteal phase support. Due to conflicting data in replacement cycles, IMP is often considered to be the standard of care. STUDY DESIGN, SIZE, DURATION Retrospective analysis of 920 frozen embryo transfer (FET) cycles between 1 January 2010 and 1 September 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients from a large, private practice undergoing autologous and donor FET using IMP or vaginal progesterone gel for luteal support were included in the analysis. IMP was used for luteal support in 682 FET cycles and vaginal progesterone gel was used in 238 FET cycles. Standard clinical outcomes of positive serum hCG levels, implantation, clinical pregnancy, spontaneous abortion and live birth were reported. MAIN RESULTS AND THE ROLE OF CHANCE The IMP and vaginal progesterone gel groups had similar patient demographics for all characteristics assessed. Implantation rates (46.4 versus 45.6%, P = 0.81), clinical pregnancy rates (61.7 versus 60.5%, P = 0.80) and live birth rates (49.1 versus 48.9%, P > 0.99) were not significantly different between IMP and vaginal progesterone gel, respectively. LIMITATIONS, REASONS FOR CAUTION This study is limited by its retrospective design and by its lack of randomization to the type of luteal support. In addition, because no a priori expected rates of success could be provided for this retrospective investigation, it was not possible to estimate statistical power associated with the various outcomes presented. WIDER IMPLICATIONS OF THE FINDINGS With the recent trends toward single embryo transfer (SET) and use of vitrified blastocysts in FET cycles, our data with ?40% of cycles being SET and use of exclusively vitrified blastocysts are more relevant to current practices than previous studies. STUDY FUNDING/COMPETING INTEREST(S) Support for data collection and analysis was provided by Actavis, Inc. D.S. has received honoraria for lectures and participation in Scientific Advisory Boards for Actavis, Inc. J.P. is an employee of Actavis, Inc. N.E. has received payment from Actavis, Inc., for her time for data collection. H.H. has received payment from Actavis, Inc., for statistical analyses. Z.P.N. has nothing to disclose. PMID:24847018

Shapiro, Daniel B.; Pappadakis, Jennifer A.; Ellsworth, Nancy M.; Hait, Howard I.; Nagy, Zsolt Peter

2014-01-01

47

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

PubMed Central

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

Chan, Wen-Hsiung

2014-01-01

48

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

49

Cytotoxic Effects of 2-Bromopropane on Embryonic Development in Mouse Blastocysts  

PubMed Central

2-Bromopropane (2-BP), an alternative to ozone-depleting solvents, is used as a cleaning solvent. Here, we examined the cytotoxic effects of 2-bromopropane (2-BP) on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, and in vivo implantation via embryo transfer. Mouse blastocysts were incubated in medium with or without 2-BP (2.5, 5 or 10 ?M) for 24 h. Cell proliferation and growth were investigated with dual differential staining, apoptosis was analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) analysis, and implantation and post-implantation development of embryos were assessed using in vitro development analysis and in vivo embryo transfer, respectively. Blastocysts treated with 5 or 10 ?M 2-BP displayed significantly increased apoptosis, and decreased inner cell mass (ICM) and trophectoderm (TE) cell number. Additionally, the implantation success rates of 2-BP-pretreated blastocysts were lower than those of untreated controls. In vitro treatment with 5 or 10 ?M 2-BP was associated with increased resorption of postimplantation embryos, and decreased placental and fetal weights. Our results collectively indicate that in vitro exposure to 2-BP induces apoptosis, suppresses implantation rates after transfer to host mice, and retards early postimplantation development. PMID:20386664

Chan, Wen-Hsiung

2010-01-01

50

Protein Conformational Dynamics Probed by Single-Molecule Electron Transfer  

Microsoft Academic Search

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

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

2003-01-01

51

Oblivious transfer based on single-qubit rotations  

E-print Network

We present a bit-string quantum oblivious transfer protocol based on single-qubit rotations. The proposed protocol does not violate the Lo's no-go theorem that prevents the unconditional security of $1$-out-of-$2$ oblivious transfer. Our protocol is based on a previously proposed quantum public key protocol and its security relies on the laws of Quantum Mechanics. We also present a single-bit oblivious transfer based on the proposed bit-string protocol. The protocol can be implemented with current technology based on optics.

J. Rodrigues; P. Mateus; N. Paunkovi?; A. Souto

2014-07-30

52

Aqueous proton transfer across single-layer graphene  

NASA Astrophysics Data System (ADS)

Proton transfer across single-layer graphene proceeds with large computed energy barriers and is therefore thought to be unfavourable at room temperature unless nanoscale holes or dopants are introduced, or a potential bias is applied. Here we subject single-layer graphene supported on fused silica to cycles of high and low pH, and show that protons transfer reversibly from the aqueous phase through the graphene to the other side where they undergo acid–base chemistry with the silica hydroxyl groups. After ruling out diffusion through macroscopic pinholes, the protons are found to transfer through rare, naturally occurring atomic defects. Computer simulations reveal low energy barriers of 0.61–0.75?eV for aqueous proton transfer across hydroxyl-terminated atomic defects that participate in a Grotthuss-type relay, while pyrylium-like ether terminations shut down proton exchange. Unfavourable energy barriers to helium and hydrogen transfer indicate the process is selective for aqueous protons.

Achtyl, Jennifer L.; Unocic, Raymond R.; Xu, Lijun; Cai, Yu; Raju, Muralikrishna; Zhang, Weiwei; Sacci, Robert L.; Vlassiouk, Ivan V.; Fulvio, Pasquale F.; Ganesh, Panchapakesan; Wesolowski, David J.; Dai, Sheng; van Duin, Adri C. T.; Neurock, Matthew; Geiger, Franz M.

2015-03-01

53

Counting the exponents of single transfer matrices  

E-print Network

The eigenvalue equation of a band or a block tridiagonal matrix, the tight binding model for a crystal, a molecule, or a particle in a lattice with random potential or hopping amplitudes: these and other problems lead to three-term recursive relations for (multicomponent) amplitudes. Amplitudes n steps apart are linearly related by a transfer matrix, which is the product of n matrices. Its exponents describe the decay lengths of the amplitudes. A formula is obtained for the counting function of the exponents, based on a duality relation and the Argument Principle for the zeros of analytic functions. It involves the corner blocks of the inverse of the associated Hamiltonian matrix. As an illustration, numerical evaluations of the counting function of quasi 1D Anderson model are shown.

Luca Guido Molinari; Giuseppe Lacagnina

2011-02-08

54

Modelling of Heat Transfer in Single Crystal Growth  

E-print Network

An attempt is made to review the heat transfer and the related problems encountered in the simulation of single crystal growth. The peculiarities of conductive, convective and radiative heat transfer in the different melt, solution, and vapour growth methods are discussed. The importance of the adequate description of the optical crystal properties (semitransparency, specular reflecting surfaces) and their effect on the heat transfer is stresses. Treatment of the unknown phase boundary fluid/crystal as well as problems related to the assessment of the quality of the grown crystals (composition, thermal stresses, point defects, disclocations etc.) and their coupling to the heat transfer/fluid flow problems is considered. Differences between the crystal growth simulation codes intended for the research and for the industrial applications are indicated. The problems of the code verification and validation are discussed; a brief review of the experimental techniques for the study of heat transfer and flow structu...

Zhmakin, Alexander I

2014-01-01

55

Cell division and death in the mouse blastocyst before implantation  

Microsoft Academic Search

The numbers of cells in the trophectoderm (TE) and inner cell mass (ICM) of mouse blastocysts were counted by differentially labelling their nuclei with two polynucleotide-specific fluorochromes. Blastocysts recovered from the uterus at intervals between their formation early on Day 4 to the initial stages of implantation on day 5 were analysed. TE cell number increase was initially rapid, indicating

Alan H. Handyside; Susan Hunter

1986-01-01

56

Role of nuclear receptors in blastocyst implantation.  

PubMed

The regulation of blastocyst implantation in the uterus is orchestrated by the ovarian hormones estrogen and progesterone. These hormones act via their nuclear receptors to direct the transcriptional activity of the endometrial compartments and create a defined period in which the uterus is permissive to embryo implantation termed the "window of receptivity". Additional members of the nuclear receptor family have also been described to have a potential role in endometrial function. Much of what we know about the function of these nuclear receptors during implantation we have learned from the use of mouse models. Transgenic murine models with targeted gene ablation have allowed us to identify a complex network of paracrine signaling between the endometrial epithelium and stroma. While some of the critical molecules have been identified, the mechanism underlying the intricate communication between endometrial compartments during the implantation window has not been fully elucidated. Defining this mechanism will help identify markers of a receptive uterine environment, ultimately providing a useful tool to help improve the fertility outlook for reproductively challenged couples. The aim of this review is to outline our current understanding of how nuclear receptors and their effector molecules regulate blastocyst implantation in the endometrium. PMID:23994285

Vasquez, Y M; DeMayo, F J

2013-12-01

57

Role of Nuclear Receptors in Blastocyst Implantation  

PubMed Central

The regulation of blastocyst implantation in the uterus is orchestrated by the ovarian hormones estrogen and progesterone. These hormones act via their nuclear receptors to direct the transcriptional activity of the endometrial compartments and create a defined period in which the uterus is permissive to embryo implantation termed the “window of receptivity”. Additional members of the nuclear receptor family have also been described to have a potential role in endometrial function. Much of what we know about the function of these nuclear receptors during implantation we have learned from the use of mouse models. Transgenic murine models with targeted gene ablation have allowed us to identify a complex network of paracrine signaling between the endometrial epithelium and stroma. While some of the critical molecules have been identified, the mechanism underlying the intricate communication between endometrial compartments during the implantation window has not been fully elucidated. Defining this mechanism will help identify markers of a receptive uterine environment, ultimately providing a useful tool to help improve the fertility outlook for reproductively challenged couples. The aim of this review is to outline our current understanding of how nuclear receptors and their effector molecules regulate blastocyst implantation in the endometrium. PMID:23994285

Vasquez, YM; DeMayo, FJ

2013-01-01

58

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

59

Culturing surplus poor-quality embryos to blastocyst stage have positive predictive value of clinical pregnancy rate  

PubMed Central

Background: Clinical reproductive centers produce large amounts of surplus poor-quality embryos annually, how to maximize the use of these embryos, and which of them have the potential to develop into blastocyst stage and influencing factors were lack of systematic research. Objective: To investigate the fate of surplus poor-quality embryos which were cultured to obtain blastocyst, determine the factors which may influence the blastulation, and discuss their application in predicting of the pregnancy outcomes. Materials and Methods: Day 3 (D3) after embryo transfer and freezing, surplus poor-quality embryos from IVF/ICSI cycles were cultured to blastocyst by the sequential method, then the blastulation outcomes were observed. Focusing on the blastulation rate of those embryos with different number cells and different embryonic grade; and last the relationship between the pregnancy outcomes of remained poor-quality embryos with successful blastulation or failed blastulation groups were studied. Results: Of 127 patients with 569 poor-quality in vitro cultured embryos, there were formation of 248 blastocysts from 91 patients (43.59%), which lead to development of 138 high-quality blastocysts (24.25%). With the increase in cells number of D 3 blastomeres, the blastulation rate gradually increased, that, 7-cell blastomeres blastulation rate was the highest (70.59%), and 8-cell blastomeres is a little below (70.37%); while the embryonic levels and blastulation rate did not show this positive relationship. The clinical pregnancy rate and implantation rate of those who had successful blastulation (67.03% and 42.39%) were higher than of those who failed to develop to blastocyst (p=0.039). Conclusion: Day 3 poor-quality embryos with successful blastulation or with failed blastulation had predictive value on pregnancy outcomes. For embryo transfer 7-8 cells grade III-IV embryo is better than 4-5 cells grade I-II embryo, in case of lack good-quality embryos. PMID:25469133

Zhu, Hai Bo; Zhang, Zhi Hong; Fadlalla, Elfateh; Wang, Rui Xue; Geng, Dong Feng; Liu, Rui Zhi

2014-01-01

60

Molecular charge-transfer interaction with single-layer graphene  

Microsoft Academic Search

While the effect of electrochemical doping on single-layer graphene (SG) with holes and electrons has been investigated, the effect of charge-transfer doping on SG has not been examined hitherto. Effects of varying the concentration of electron donor and acceptor molecules such as tetrathiafulvalene (TTF) and tetracyanoethylene (TCNE) on SG produced by mechanical exfoliation as well as by the reduction of

Dattatray J. Late; Anupama Ghosh; Biswanath Chakraborty; A. K. Sood; Umesh V. Waghmare; C. N. R. Rao

2011-01-01

61

Microscale heat transfer mechanisms of single-bubble nucleation events  

Microsoft Academic Search

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

Saeed Moghaddam; Ken Kiger

2006-01-01

62

The relative myth of elective single embryo transfer  

Microsoft Academic Search

The option of single embryo transfer (SET) has recently dominated the pages of this and other medical journals. Opinions, in regards to the utility of such an approach, appear to differ between Europe and the US. While US guide- lines promote a more individualized approach, European opinions, at times, even advocate mandated practice pat- terns. The European approach, however, fails

Norbert Gleicher; David Barad

2006-01-01

63

Cytologic evidence for preferential inactivation of the paternally derived X chromosome in XX mouse blastocysts  

Microsoft Academic Search

A total of 941 mouse blastocysts obtained from two types of crosses in which one of parents carried Cattanach’s X\\/autosome translocation was studied cytogenetically by quinacrine mustard fluorescence. The rearranged X (Xt) and the normal X (Xn) were distinguished by size. Karyotype analysis was successful in 721 embryos, of which 205 were heterozygous for Cattanach’s translocation. A single heterochromatic and

N. Takagi; N. Wake; M. Sasaki

1978-01-01

64

Comparison of ES cell fate in sandwiched aggregates and co-cultured aggregates during blastocyst formation by monitored GFP expression.  

PubMed

Markers and the means to detect them are required to monitor the fate of living cells. However, few suitable markers for living cells were known until a green fluorescent protein (GFP) was discovered. We have established mouse embryonic stem (ES) cell lines that express mutant GFP under the chicken beta-actin (CAG) promoter. Using these cell lines, we were able to follow the migration of ES cells during blastocyst formation both in sandwiching and coculture methods, even if only a single ES cell was used. Furthermore, the contribution of ES cells to the inner cell mass (ICM) was easily estimated at the blastocyst stage. We compared sandwiching with coculture aggregation relative to the contribution of the ES cell in the ICM, and the results indicated that there was no difference in the ratios of chimeric embryos having ICM contributed from cultured ES cells. Furthermore, an aggregated single ES cell was able to contribute three or four cells to the ICM at the blastocyst stage. Thus we conclude that one, instead of two, embryos is enough to make aggregation with ES cells, and a single ES cell attached to an embryo is enough to produce germline chimeras. Moreover, we could clearly observe single cell fate during blastocyst formation. This suggests that our established cell line can be used for monitoring single cell fate in vivo. In addition, we have shown that up to five doses of 30 sec of UV irradiation using GFP filters have no effect on the embryonic development. PMID:10092117

Shimada, H; Kaname, T; Suzuki, M; Hitoshi, Y; Araki, K; Imaizumi, T; Yamamura, K

1999-04-01

65

Aqueous proton transfer across single-layer graphene  

PubMed Central

Proton transfer across single-layer graphene proceeds with large computed energy barriers and is therefore thought to be unfavourable at room temperature unless nanoscale holes or dopants are introduced, or a potential bias is applied. Here we subject single-layer graphene supported on fused silica to cycles of high and low pH, and show that protons transfer reversibly from the aqueous phase through the graphene to the other side where they undergo acid–base chemistry with the silica hydroxyl groups. After ruling out diffusion through macroscopic pinholes, the protons are found to transfer through rare, naturally occurring atomic defects. Computer simulations reveal low energy barriers of 0.61–0.75?eV for aqueous proton transfer across hydroxyl-terminated atomic defects that participate in a Grotthuss-type relay, while pyrylium-like ether terminations shut down proton exchange. Unfavourable energy barriers to helium and hydrogen transfer indicate the process is selective for aqueous protons. PMID:25781149

Achtyl, Jennifer L.; Unocic, Raymond R.; Xu, Lijun; Cai, Yu; Raju, Muralikrishna; Zhang, Weiwei; Sacci, Robert L.; Vlassiouk, Ivan V.; Fulvio, Pasquale F.; Ganesh, Panchapakesan; Wesolowski, David J.; Dai, Sheng; van Duin, Adri C. T.; Neurock, Matthew; Geiger, Franz M.

2015-01-01

66

Aqueous proton transfer across single-layer graphene.  

PubMed

Proton transfer across single-layer graphene proceeds with large computed energy barriers and is therefore thought to be unfavourable at room temperature unless nanoscale holes or dopants are introduced, or a potential bias is applied. Here we subject single-layer graphene supported on fused silica to cycles of high and low pH, and show that protons transfer reversibly from the aqueous phase through the graphene to the other side where they undergo acid-base chemistry with the silica hydroxyl groups. After ruling out diffusion through macroscopic pinholes, the protons are found to transfer through rare, naturally occurring atomic defects. Computer simulations reveal low energy barriers of 0.61-0.75?eV for aqueous proton transfer across hydroxyl-terminated atomic defects that participate in a Grotthuss-type relay, while pyrylium-like ether terminations shut down proton exchange. Unfavourable energy barriers to helium and hydrogen transfer indicate the process is selective for aqueous protons. PMID:25781149

Achtyl, Jennifer L; Unocic, Raymond R; Xu, Lijun; Cai, Yu; Raju, Muralikrishna; Zhang, Weiwei; Sacci, Robert L; Vlassiouk, Ivan V; Fulvio, Pasquale F; Ganesh, Panchapakesan; Wesolowski, David J; Dai, Sheng; van Duin, Adri C T; Neurock, Matthew; Geiger, Franz M

2015-01-01

67

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

PubMed Central

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

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

2014-01-01

68

Identification of four genes required for mammalian blastocyst formation.  

PubMed

RNA transcription, processing and translation are fundamental molecular processes required for development, growth and cell viability. Towards the functional annotation of the genome, we are engaged in a reverse genetic screen using mammalian preimplantation embryos as a model system. Here we report the essential function of four RNA processing/splicing factors (Sf3b14, Sf3b1, Rpl7l1, and Rrp7a) and show that each of these genes is required for blastocyst formation in the mouse. As very little information is known about these genes, we characterized their normal expression and localization in mouse embryos as well as phenotypic analysis of loss of function during preimplantation development. Functional knockdown of each gene product results in normal morula development but there is failure to form a blastocoel cavity or morphologically differentiated trophectoderm. We show that zygotic genome activation does occur as well as initial lineage specification in the absence of each factor. Consistent with a role in RNA splicing, we demonstrate that the absence of Sf3b14 and Sf3b1 in 8-cell and morula-stage embryos results in a specific reduction of intron containing transcripts, but no reduction single-exon genes. Taken together, we show critical developmental and molecular requirements of Sf3b14, Sf3b1, Rpl7l1, and Rrp7a during mammalian preimplantation. PMID:23211737

Maserati, Marc; Dai, Xiangpeng; Walentuk, Melanie; Mager, Jesse

2014-08-01

69

Single Electron Transfer Living Radical Polymerization via a New Initiator  

NASA Astrophysics Data System (ADS)

Research and development of novel initiating system such as single electron transfer living radical polymerization (SET-LRP) is of high importance in polymer chemistry. A new SET-LRP initiator was synthesized and applied to prepare end-functionalized poly(methyl methacrylate) (PMMA) in this study. ?-Trichloromethyl benzyl alcohol was firstly synthesized, followed by preparation of PMMA under SET-LRP conditions. Conversion of MMA was 81.9%, and the molecular weight of PMMA was about 2.5 kDa at 60 °C for 1 h. Consistency of the number-average molecular weight of PMMA from NMR, GPC and theoretical calculation indicated that the polymerization featured controllable property. Broad molecular weight distribution (MWD) may be ascribed to branched polymers formed by initiation and chain transfer.

Bai, Xiongxiong; Hu, Ying; Zhang, Xu; Ai, Lingling; Cheng, Chuanjie

2014-08-01

70

Condensation heat transfer of steam on a single horizontal tube  

NASA Astrophysics Data System (ADS)

An experimental apparatus was designed, constructed and instrumented in an effort to systematically and carefully study the condensation heat-transfer coefficient on a single, horizontal tube. A smooth, thick-walled copper tube of length 133.5 mm, with an outside diameter of 15.9 mm and an inside diameter of 12.7 mm was instrumented with six wall thermocouples. The temperature rise across the test section was measured accurately using quartz crystal thermometers. The inside heat-transfer coefficient was determined using the Sieder-Tate correlation with leading coefficient of 0.029. Initial steam side data were taken at atmospheric pressure to test the data acquisition/reduction computer programs.

Graber, K. A.

1983-06-01

71

Avoidance of multiple pregnancy by use of single embryo transfer.  

PubMed

The benefits of single embryo transfer (SET) for both mother and child are evident. Already twin pregnancies constitute a relatively serious problem exemplified by the incidence of cerebral palsy, which will increase significantly as well as a risk for premature birth. Selective embryo reduction in countries where this is allowed may be one way to acutely solve the situation. In the beginning the use of natural cycle in vitro fertilization (IVF) avoided the problem, but with the introduction of controlled ovarian hyperstimulation predominantly by use of gonadotrophins in the early 1980ies the temptation to replace more than 1 embryo at a time became too strong. SET with maintenance of acceptable pregnancy rates can only be achieved if tools (improved morphological criteria, biomarkers, preimplantation genetic screening) to select the most viable/normal embryos are at hand together with improved cryopreservation procedures. In reports from Finland and Belgium already 5 years ago, elective single embryo transfer (eSET) was shown to reach almost the same success rates as double embryo transfer (DET) in selective patient groups (age under 37, good quality embryos). The indications for eSET have increased during the last years. In Finland the initiative came from the IVF clinics while in Sweden a legislative process (in act from January 2003) resulted in the recommendation that eSET should be used in the vast majority of the IVF cycles. In both these Nordic countries around 60% of the transfers are today eSET and the multiple pregnancy rate below 10% with no triplets. From an economical point of view, it is of course evident that multiple pregnancies with the numerous potential complications should be avoided altogether. Countries where IVF is included in the government health insurance will thus most likely show the way towards an even more successful, safer and cheaper treatment of infertile couples in the future. PMID:15758862

Hamberger, L; Hardarson, T; Nygren, K G

2005-02-01

72

Regulatory microRNA Network Identification in Bovine Blastocyst Development  

PubMed Central

Mammalian blastocyst formation is characterized by two lineage segregations resulting in the formation of the trophectoderm, the hypoblast, and the epiblast cell lineages. Cell fate determination during these early lineage segregations is associated with changes in the expression of specific transcription factors. In addition to the transcription factor-based control, it has become clear that also microRNAs (miRNAs) play an important role in the post-transcriptional regulation of pluripotency and differentiation. To elucidate the role of miRNAs in early lineage segregation, we compared the miRNA expression in early bovine blastocysts with the more advanced stage of hatched blastocysts. Reverse transcription–quantitative PCR-based miRNA expression profiling revealed eight upregulated miRNAs (miR-127, miR-130a, miR-155, miR-196a, miR-203, miR-28, miR-29c, and miR-376a) and four downregulated miRNAs (miR-135a, miR-218, miR-335, and miR-449b) in hatched blastocysts. Through an integrative analysis of matching miRNA and mRNA expression data, candidate miRNA-mRNA interaction pairs were prioritized for validation. Using an in vitro luciferase reporter assay, we confirmed a direct interaction between miR-218 and CDH2, miR-218 and NANOG, and miR-449b and NOTCH1. By interfering with the FGF signaling pathway, we found functional evidence that miR-218, mainly expressed in the inner cell mass, regulates the NANOG expression in the bovine blastocyst in response to FGF signaling. The results of this study expand our knowledge about the miRNA signature of the bovine blastocyst and of the interactions between miRNAs and cell fate regulating transcription factors. PMID:23398486

Mestdagh, Pieter; Lefever, Steve; Van Poucke, Mario; Van Zeveren, Alex; Van Soom, Ann; Vandesompele, Jo; Peelman, Luc

2013-01-01

73

Rabbit blastocysts accumulate (/sup 3/H)prostaglandins in vitro  

SciTech Connect

Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with /sup 3/H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of (/sup 3/H)PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of (/sup 3/H)PGE2 and (/sup 3/H)PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the (/sup 3/H)PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. The authors conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

Jones, M.A.; Harper, M.J.

1984-08-01

74

Choline inhibition of amino acid transport in preimplantation mouse blastocysts  

SciTech Connect

Addition of 70 mM choline chloride to Brinster's medium (140 mM Na/sup +/) inhibited uptake of approx. 1 ..mu..M (/sup 3/H)glycine, leucine, lysine and alanine in blastocysts by about 50% each during a five-minute incubation period at 37/sup 0/C, whereas 70 mM LiCl, sodium acetate and NaCl or 140 mM mannitol had no effect. They attribute the apparent linear relationship between Gly transport in blastocysts and the square of the (Na/sup +/), observed when choline was substituted for Na/sup +/ in Brinster's medium, to concomitant, concentration-dependent enhancement and inhibition of transport by Na/sup +/ and choline, respectively. As expected, Gly uptake and the (Na/sup +/) were linearly related up to 116 mM Na/sup +/, when Na/sup +/ was replaced with Li/sup +/. The rates of Na/sup +/-independent Gly and Ala uptake were <5% and <2% of the total, respectively, and similar when either Li/sup +/ or choline replaced Na/sup +/. Therefore, neither Li/sup +/ nor choline appears to substitute for Na/sup +/ in supporting Na/sup +/-dependent transport in blastocysts. Na/sup +/-independent Leu uptake was 20 times faster than Gly or Ala uptake and appeared to be inhibited by choline in blastocysts since it was about 37% slower when choline instead of Li/sup +/ was substituted for Na/sup +/. In contrast to blastocysts, choline had no effect on amino acid transport in cleavage-stage mouse embryos. The unexpected sensitivity of transport to choline in blastocysts underscores the importance of testing the effects of this substance when it is used to replace Na/sup +/ in new transport studies.

Campione, A.L.; Haghighat, N.; Gorman, J.; Van Winkle, L.J.

1987-05-01

75

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

PubMed Central

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

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

2012-01-01

76

Vitrification solution without sucrose for cryopreservation in mouse blastocysts  

PubMed Central

Objective This study was designed to investigate the survival rate of vitrified mouse blastocysts depending on the presence or absence of sucrose in vitrification solution. Methods Mouse two-cell embryos were collected and cultured to blastocysts. Two vitrification solutions were prepared. The control solution was composed of 25% glycerol, 25% ethylene glycol, and 0.5 M sucrose (G25E250.5S) containing 2.5 mL glycerol, 2.5 mL ethylene glycol, 2 mL SSS, and 0.855 g sucrose in 5 mL PB1. The experimental solution was composed of 25% glycerol and 25% ethylene glycol (G25E25) and contained 2.5 mL glycerol and 2.5 mL ethylene glycol in 5 mL PB1. Artificial shrinkage was conducted by aspirating the blastocoelic fluid using an ICSI pipette. To examine the effect of sucrose in the vitrification solution on the survival rate of mouse blastocysts, the shrunken-equilibrated blastocysts were rehydrated or vitrified after being exposed to one of the two vitrification solutions. After exposure and the vitrification-thawing process, the re-expansion rate and hatching rate were evaluated after 6 hours of in vitro culture. Results The re-expansion rate of mouse blastocysts exposed to vitrification solution with and without sucrose were not different in the experimental solution (without sucrose) (98%) and the control solution (with sucrose) (92%) (p>0.05). The hatching rate was higher in the experimental solution (95%) than in the control solution (88%), but did not differ across two treatments (p>0.05). The re-expansion rate of mouse blastocysts vitrified in the control solution was 92% and 94%, respectively (p>0.05), and the hatching rate was higher in the experimental solution (90%) than in the control solution (74%) (p<0.05). Conclusion Sucrose need not be added in vitrification solution for freezing of artificially shrunken mouse blastocysts. PMID:25309855

Joo, Jong Kil; Lee, Young Ju; Jeong, Ju Eun; Kim, Seung Chul; Ko, Gyoung Rae

2014-01-01

77

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

E-print Network

Charge Transfer through Single-Stranded Peptide Nucleic Acid Composed of Thymine Nucleotides Amit; In Final Form: February 18, 2008 Self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids. Peptide nucleic acid (PNA) is an analo

Borguet, Eric

78

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

E-print Network

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. ...

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

2011-04-12

79

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

PubMed

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

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

2005-01-01

80

SINGLE-PHASE LIQUID HEAT TRANSFER IN PLAIN AND ENHANCED MICROCHANNELS Mark E. Steinke  

E-print Network

SINGLE-PHASE LIQUID HEAT TRANSFER IN PLAIN AND ENHANCED MICROCHANNELS Mark E. Steinke Systems upon the understanding of the fundamental heat transfer processes that occur in these systems. There have been great advancements in our understanding of the heat transfer and fluid flow mechanisms

Kandlikar, Satish

81

1 Copyright 2006 by ASME PRESSURE DROP AND HEAT TRANSFER IN A SINGLE-PHASE  

E-print Network

1 Copyright © 2006 by ASME PRESSURE DROP AND HEAT TRANSFER IN A SINGLE-PHASE MICRO-PIN-FIN HEAT-956-2373 e-mail: qu@hawaii.edu ABSTRACT The pressure drop and heat transfer characteristics of a single = . The measured pressure drop and temperature distribution were used to evaluate average friction factor and local

Qu, Weilin

82

Single-collision studies of energy transfer and chemical reaction  

SciTech Connect

The research focus in this group is state-to-state dynamics of reaction and energy transfer in collisions of free radicals such as H, OH, and CH{sub 3} with H{sub 2}, alkanes, alcohols and other hydrogen-containing molecules. The motivation for the work is the desire to provide a detailed understanding of the chemical dynamics of prototype reactions that are important in the production and utilization of energy sources, most importantly in combustion. The work is primarily experimental, but with an important and growing theoretical/computational component. The focus of this research program is now on reactions in which at least one of the reactants and one of the products is polyatomic. The objective is to determine how the high dimensionality of the reactants and products differentiates such reactions from atom + diatom reactions of the same kinematics and energetics. The experiments use highly time-resolved laser spectroscopic methods to prepare reactant states and analyze the states of the products on a single-collision time scale. The primary spectroscopic tool for product state analysis is coherent anti-Stokes Raman scattering (CARS) spectroscopy. CARS is used because of its generality and because the extraction of quantum state populations from CARS spectra is straightforward. The combination of the generality and easy analysis of CARS makes possible absolute cross section measurements (both state-to-state and total), a particularly valuable capability for characterizing reactive and inelastic collisions. Reactant free radicals are produced by laser photolysis of appropriate precursors. For reactant vibrational excitation stimulated Raman techniques are being developed and implemented.

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

1993-12-01

83

In vivo-derived horse blastocysts show transcriptional upregulation of developmentally important genes compared with in vitro-produced horse blastocysts.  

PubMed

In vitro-produced (IVP) equine blastocysts can give rise to successful pregnancies, but their morphology and developmental rate differ from those of in vivo-derived equine blastocysts. The aim of the present study was to evaluate this difference at the genetic level. Suppression subtractive hybridisation (SSH) was used to construct a cDNA library enriched for transcripts preferentially expressed in in vivo-derived equine blastocysts compared with IVP blastocysts. Of the 62 different genes identified in this way, six genes involved in embryonic development (BEX2, FABP3, HSP90AA1, MOBKL3, MCM7 and ODC) were selected to confirm this differential expression by reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). Using RT-qPCR, five genes were confirmed to be significantly upregulated in in vivo-derived blastocysts (i.e. FABP3, HSP90AA1 (both P<0.05), ODC, MOBKL3 and BEX2 (P<0.005 for all three)), confirming the results of the SSH. There was no significant difference in MCM7 expression between IVP and in vivo-derived blastocysts. In conclusion, five genes that are transcriptionally upregulated in in vivo-derived equine blastocysts compared with IVP blastocysts have been identified. Because of their possible importance in embryonic development, the expression of these genes can be used as a marker to evaluate in vitro embryo production systems in the horse. PMID:21211470

Smits, Katrien; Goossens, Karen; Van Soom, Ann; Govaere, Jan; Hoogewijs, Maarten; Peelman, Luc J

2011-01-01

84

Blastocyst production from in vitro-produced day-2 bovine embryos classified by cleavage stage, and cytogenetical evaluation of the resultant day-8 blastocysts.  

PubMed

The present study was conducted to determine the criteria for selecting good quality embryos on Day-2 post-insemination and at the blastocyst stage. Bovine oocytes were matured, fertilized and cultured in vitro. First, Day-2 embryos were classified based on the number of blastomeres into 2-cell, 3- to 4-cell, 5- to 8-cell and >8-cell stage embryos; chromosome samples were then prepared. In the second experiment, the Day-2 embryos classified according to the number of blastomeres were cultured separately for an additional 6 days (Day 8). The resultant Day-8 blastocysts from each group of Day-2 embryos were classified into the following 3 grades based on morphology and diameter: Grade A, hatched and hatching blastocysts; Grade B, expanded blastocysts; and Grade C, unexpanded blastocysts. Chromosome samples were then prepared. The 5- to 8-cell stage Day-2 embryos had the lowest incidence of chromosomal abnormalities (13.5%, P<0.05) and the highest development rate to blastocysts (59.2%, P<0.05). Furthermore, the blastocysts derived from the 5- to 8-cell stage embryos had the largest mean number of cells (102.8+/-42.4, P<0.05), largest number of metaphases per blastocyst (9.5+/-4.8, P<0.05) and lowest incidence of chromosomal abnormalities (24.6%, P<0.05). The Grade A blastocysts had the largest mean number of cells (136.6+/-33.4, P<0.05), a large number of metaphases per blastocyst (11.9+/-5.5, P<0.05) and a low incidence of severe chromosomal abnormalities (17.3%). The results showed that, at Day 2, the 5- to 8-cell stage embryos were of better quality since they had the lowest incidence of chromosomal abnormalities and the highest blastocyst rate and the resultant blastocysts had the largest number of cells and lowest incidence of chromosomal abnormalities. In particular, selection of Grade A blastocysts can improve the development rate to term. PMID:18957827

Ulloa Ulloa, Carlos Manuel; Yoshizawa, Midori; Yamashita, Akira; Hama, Satoshi; Mitsui, Akinori; Hashi, Chaomulige; Abe, Hiroyuki; Hoshi, Hiroyoshi; Fukui, Emiko; Matsumoto, Hiromichi

2008-12-01

85

Microsatellite DNA analysis proves nucleus of interspecies reconstructed blastocyst coming from that of donor giant panda  

Microsoft Academic Search

A method for DNA isolation from early development of blastocyst and further analysis of nuclear and mitochondrial DNA was\\u000a developed in present study. Total DNA was prepared from interspecies reconstructed blastocyst and a giant panda specific microsatellite\\u000a locus g010 was successfully amplified. DNA sequencing of the PCR product showed that two sequences of reconstructed blastocysts are\\u000a the same as that

Bo Ding; Peng Shi; Jinggong Xiangyu; Yaping Zhang; Dayuan Chen; Qingyuan Sun; Guangpeng Li; Minkang Wang; Yilong Liu; Li Kang; Zhiming Han; Xiangfen Song; Jingsong Li; Yuchun Chen

2000-01-01

86

Enhanced single-phase heat transfer for ocean thermal energy conversion systems  

Microsoft Academic Search

The utilization of enhanced heat transfer surfaces for both the boiler and condenser was investigated in order to reduce the size and cost of OTEC systems. It was found that single phase, forced convection heat transfer can be enhanced by a wide variety of techniques which do not require external power to generate and sustain. These techniques are: rough surfaces,

A. E. Bergles; M. K. Jensen

1977-01-01

87

Heat transfer to a single particle exposed to a thermal plasma  

Microsoft Academic Search

This paper is concerned with an analytical study of the heat and mass transfer process of a single particle exposed to a thermal plasma, with emphasis on the effects which evaporation imposes on heat transfer from the plasma to the particle. The results refer mainly to an atmospheric-pressure argon plasma and, for comparison purposes, an argon-hydrogen mixture and a nitrogen

Xi Chen; E. Pfender

1982-01-01

88

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

E-print Network

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

Aussillous, Pascale

89

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

E-print Network

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

Turro, Claudia

90

Single-node orbit analsyis with radiation heat transfer only  

NASA Technical Reports Server (NTRS)

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

Peoples, J. A.

1977-01-01

91

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

Microsoft Academic Search

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

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

1995-01-01

92

Unexpected Hole Transfer Leads to High Efficiency Single-Walled Carbon Nanotube  

E-print Network

Unexpected Hole Transfer Leads to High Efficiency Single-Walled Carbon Nanotube Hybrid Photovoltaic photovoltaics. KEYWORDS Carbon nanotube, P3HT, hybrid photovoltaics, hole acceptor I n organic photovoltaic1 photovoltaics, including heterojunction devices be- tween one-dimensional systems of single-walled carbon

Zhong, Zhaohui

93

Energy Transfer in Single-Molecule Photonic Wires  

Microsoft Academic Search

The ultimate goal in device miniaturisation aims at the incor- poration of single molecules as building blocks for the con- struction of molecule-based electronic, mechanical and optical devices. Molecular electronics, for instance, is emerging as a field that will conjecturally resolve the quest to scale electron- ics beyond the limit of \\

Gabriel Sanchez Mosteiro; Jacob P. Hoogenboom; Erik M. H. P. van Dijk; Niek. F. van Hulst

2005-01-01

94

Chemical reaction fouling model for single-phase heat transfer  

SciTech Connect

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

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

1993-08-01

95

Charge transfer events in semiconducting single-wall carbon nanotubes.  

PubMed

Electron-donating ferrocene units have been attached to SWNTs, with different degrees of functionalization. By means of a complementary series of novel spectroscopic techniques (i.e., steady-state and time-resolved), we have documented that mutual interactions between semiconducting SWNT and the covalently attached electron donor (i.e., ferrocene) lead, in the event of photoexcitation, to the formation of radical ion pairs. In the accordingly formed radical ion pairs, oxidation of ferrocene and reduction of SWNT were confirmed by spectroelectrochemistry. It is, however, shown that only a few semiconducting SWNTs [i.e., (9,4), (8,6), (8,7), and (9,7)] are susceptible to photoinduced electron transfer processes. These results are of relevant importance for the development of SWNT-based photovoltaics. PMID:22039995

Oelsner, Christian; Herrero, M Antonia; Ehli, Christian; Prato, Maurizio; Guldi, Dirk M

2011-11-23

96

Chemical reaction fouling model for single-phase heat transfer  

NASA Astrophysics Data System (ADS)

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

Panchal, C. B.; Watkinson, A. P.

97

Single-class SVM and directed transfer function approach to the localization of the region containing epileptic focus  

E-print Network

Single-class SVM and directed transfer function approach to the localization of the region Epileptic focus localization Directed transfer function One-class SVM a b s t r a c t The paper presents the study concerning the application of a single-class support vector machine (SVM) and directed transfer

Cichocki, Andrzej

98

Diameter selective electron transfer from encapsulated ferrocenes to single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT.The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT. Electronic supplementary information (ESI) available: Calculated binding energies of FeCp2@SWCNTs and additional spectroscopic characterization are described in ESI. See DOI: 10.1039/c4nr04398g

Iizumi, Yoko; Suzuki, Hironori; Tange, Masayoshi; Okazaki, Toshiya

2014-10-01

99

Expression of HSG is essential for mouse blastocyst formation  

SciTech Connect

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

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

2005-09-23

100

Single and double charge transfer of He(2+) ions with molecules at near-thermal energies  

NASA Technical Reports Server (NTRS)

Rate coefficients were measured for charge-transfer reactions of He(2+) 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-model (Su and Bowers, 1973) 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.

1993-01-01

101

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

102

Intermittent Single-molecule Interfacial Electron Transfer Dynamics in Dye-TiO2 Nanoparticle systems  

NASA Astrophysics Data System (ADS)

Photosensitized interfacial electron transfer dynamics of single molecules of Coumarin 343 (C343) and Cresyl Violet (CV+) acetate dyes adsorbed at TiO2 nanoparticle (NP)-polymer and TiO2 NP-electrolyte interfaces are studied using single-molecule photon-stamping fluorescence spectroscopy. Fluorescence intensity trajectories of individual dye molecules adsorbed at a TiO2 NP-polymer interface in air showed intermittent 'on' and 'off' (blinking) fluorescence in sub-second to second time scales, which are well distinguished from blinking due to intersystem crossing to dark triplet state. Autocorrelation analyses of the intensity trajectories showed non-exponential fluctuation dynamics for the single molecules, and the average rates are of 5 s-1 for both the C343-TiO2 and CV+-TiO2 systems. We attribute the fluorescence intensity fluctuation to the intermittency of the single-molecule interfacial electron transfer reactivity and dynamics.

Biju, Vasudevanpillai; Micic, Miodrag; Hu, Dehong; Lu, H. Peter

2004-03-01

103

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

104

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

105

Single-input/single-output transfer functions for a flexible slewing link  

NASA Technical Reports Server (NTRS)

Truncated linear models based on constrained and unconstrained mode expansions for a flexible link with torque actuation at its hub led us to examine the behavior of the open-loop-zeros of five commonly used SISO transfer functions. We arrive at new conclusions with regard to minimum- and non-minimum-phase zeros, and passivity of the transfer functions. The flexible-to-rigid inertia (FRI) ratio plays an important role in the determination of these characteristics. This paper illustrates how the zero locations of some of the transfer functions are dramatically affected by the FRI ratio. We also investigate the performance of a hub angle, hub rate, and relative tip position static feedback controller based on a reduced-order constrained mode model when applied to both unconstrained and constrained mode models of the same dimension. Simulations indicate that the constrained model can be stable while the unconstrained model is not for high FRI ratios. Our findings can provide useful information to designers in cases where the controller is sensitive to the 1ocation of the plant's zeros.

Barbieri, Enrique

1993-01-01

106

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

E-print Network

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

Croquette, Vincent

107

Dynamics exploration of a single-track rigid car model with load transfer  

Microsoft Academic Search

In this paper we explore the dynamics of a single-track car model. We develop a model of a rigid car inspired to the well known bicycle model. The bicycle model is a planar rigid model that approximates the vehicle as a rigid body with two wheels. However, the bicycle model does not allow to describe the effect of load transfer,

Alessandro Rucco; Giuseppe Notarstefano; John Hauser

2010-01-01

108

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

109

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

110

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

SciTech Connect

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 {sup 66}Cu (I{sup p}i 6{sup -}, E{sub x} = 1154 keV, T{sub 1/2} = 595(20) ns) in single nucleon transfer and the population of mus isomers in {sup 66}Cu and {sup 63}Ni in multi-nucleon transfer. The experimentally tested methodology allows broad applications toward more exotic species and feasibility of these reactions to produce species away from stability.

Lozeva, R. L.; Georgiev, G. P.; Audi, G.; Cabaret, S.; Fiori, E.; Gaulard, C.; Hauschilda, K.; Lopez-Martens, A.; Risegari, L. [CSNSM, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay-Campus (France); Balabanski, D. L. [INRNE, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Blazhev, A.; Jolie, J.; Moschner, K.; Zell, K.-O. [IKP, Universitaet zu Koeln, DE-50937 Cologne (Germany); Daugas, J.-M.; Faul, T.; Morel, P.; Roig, O. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France); Ferraton, M.; Ibrahim, F. [IPN, CNRS/IN2P3, F-91406 Orsay-Campus (France)

2010-04-30

111

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

PubMed Central

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

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

2014-01-01

112

Energy Transfer in Reconstituted Peridinin-Chlorophyll-Protein Complexes: Ensemble and Single-Molecule Spectroscopy Studies  

PubMed Central

We combine ensemble and single-molecule spectroscopy to gain insight into the energy transfer between chlorophylls (Chls) in peridinin-chlorophyll-protein (PCP) complexes reconstituted with Chl a, Chl b, as well as both Chl a and Chl b. The main focus is the heterochlorophyllous system (Chl a/b-N-PCP), and reference information essential to interpret experimental observations is obtained from homochlorophyllous complexes. Energy transfer between Chls in Chl a/b-N-PCP takes place from Chl b to Chl a and also from Chl a to Chl b with comparable Förster energy transfer rates of 0.0324 and 0.0215 ps?1, respectively. Monte Carlo simulations yield the ratio of 39:61 for the excitation distribution between Chl a and Chl b, which is larger than the equilibrium distribution of 34:66. An average Chl a/Chl b fluorescence intensity ratio of 66:34 is measured, however, for single Chl a/b-N-PCP complexes excited into the peridinin (Per) absorption. This difference is attributed to almost three times more efficient energy transfer from Per to Chl a than to Chl b. The results indicate also that due to bilateral energy transfer, the Chl system equilibrates only partially during the excited state lifetimes. PMID:17675350

Mackowski, Sebastian; Wörmke, Stephan; Brotosudarmo, Tatas H. P.; Jung, Christophe; Hiller, Roger G.; Scheer, Hugo; Bräuchle, Christoph

2007-01-01

113

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

E-print Network

Experimental and numerical study of pressure drop and heat transfer in a single-phase micro Received 6 July 2001; received in revised form 26 October 2001 Abstract The pressure drop and heat transfer-dimensional heat transfer characteristics of the heat sink were analyzed numerically by solving the conjugate heat

Qu, Weilin

114

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

E-print Network

Microjet array single-phase and flow boiling heat transfer with R134a Eric A. Browne a , Gregory J boiling a b s t r a c t An experimental study of single-phase and flow boiling heat transfer:6 6 Nud 6 128. Boiling experiments were conducted with liquid subcoolings of 10, 20, and 30 °C at jet

Peles, Yoav

115

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

PubMed

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

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

2014-12-01

116

Near-infrared fluorescent single walled carbon nanotube-chitosan composite: Interfacial strain transfer efficiency assessment  

NASA Astrophysics Data System (ADS)

Effective load transfer at the single walled carbon nanotube (SWCNT)-polymer interface is most desirable for mechanically reinforced polymer composites. Versatile layer-by-layer assembly technique achieved dispersion and uniform distribution of sodium carboxymethylcellulose (CMC)-solubilized SWCNTs within the polymer matrix. Electrostatic interaction between positively charged chitosan and negatively charged CMC facilitates design of an optically active biocompatible nanocomposite. Interfacial strain transfer efficiency of SWCNT-chitosan nanocomposite was assessed via SWCNT Raman and photoluminescence band shifts under uniaxial strain. Photoluminescence peak shift rates of individual semiconducting SWCNTs were investigated and compared with tight binding model calculations.

Mol Menamparambath, Mini; Arabale, Girish; Nikolaev, Pavel; Baik, Seunghyun; Arepalli, Sivaram

2013-04-01

117

3D numerical simulation of heat transfer during horizontal direct crystallization of corundum single crystals  

NASA Astrophysics Data System (ADS)

This paper describes the numerical simulation of heat transfer in a system for growing corundum single-crystal plates (leucosapphire and ruby) of size 200×200 mm. A mathematical model accounting for the radiative and conductive heat transfer has been developed. Three-dimensional computations have been made with minor simplifications of the furnace geometry. The thermal fields at various positions of the crystal container and the effect of various setup units and their design on the temperature distribution are analyzed. The computed crystallization front shape is compared with the available experimental data. Numerical analysis was used to optimize the hot zone design.

Lukanina, M. A.; Hodosevitch, K. V.; Kalaev, V. V.; Semenov, V. B.; Sytin, V. N.; Raevsky, V. L.

2006-01-01

118

Sall4 regulates distinct transcription circuitries in different blastocyst-derived stem cell lineages.  

PubMed

Stem cells self-renew or differentiate under the governance of a stem-cell-specific transcriptional program, with each transcription factor orchestrating the activities of a particular set of genes. Here we demonstrate that a single transcription factor is able to regulate distinct core circuitries in two different blastocyst-derived stem cell lines, embryonic stem cells (ESCs) and extraembryonic endoderm (XEN) cells. The transcription factor Sall4 is required for early embryonic development and for ESC pluripotency. Sall4 is also expressed in XEN cells, and depletion of Sall4 disrupts self-renewal and induces differentiation. Genome-wide analysis reveals that Sall4 is regulating different gene sets in ESCs and XEN cells, and depletion of Sall4 targets in the respective cell types induces differentiation. With Oct4, Sox2, and Nanog, Sall4 forms a crucial interconnected autoregulatory network in ESCs. In XEN cells, Sall4 regulates the key XEN lineage-associated genes Gata4, Gata6, Sox7, and Sox17. Our findings demonstrate how Sall4 functions as an essential stemness factor for two different stem cell lines. PMID:18804426

Lim, Chin Yan; Tam, Wai-Leong; Zhang, Jinqiu; Ang, Haw Siang; Jia, Hui; Lipovich, Leonard; Ng, Huck-Hui; Wei, Chia-Lin; Sung, Wing Kin; Robson, Paul; Yang, Henry; Lim, Bing

2008-11-01

119

Single-step transfer or exchange of multipartite quantum entanglement with minimum resources  

E-print Network

The transfer or exchange of multipartite quantum states is critical to the realization of large-scale quantum information processing and quantum communication. A challenging question in this context is: What is the minimum resource required and how to simultaneously transfer or exchange multipartite quantum entanglement between two sets of qubits. Finding the answer to these questions is of great importance to quantum information science. In this work, we demonstrate that by using a single quantum two-level system - the simplest quantum object - as a coupler arbitrary multipartite quantum states (either entangled or separable) can be transferred or exchanged simultaneously between two sets of qubits. Our findings offer the potential to significantly reduce the resources needed to construct and operate large-scale quantum information networks consisting of many multi-qubit registers, memory cells, and processing units.

Chui-Ping Yang; Qi-Ping Su; Shi-Biao Zheng; Siyuan Han

2014-10-12

120

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

NASA Astrophysics Data System (ADS)

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

Ramakrishnan, Raghunathan; Nest, Mathias

2015-01-01

121

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

122

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

123

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

124

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

PubMed Central

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

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

2014-01-01

125

Electron transfer-based single molecule fluorescence as a probe for nano-environment dynamics.  

PubMed

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

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

2014-01-01

126

Single CuTCNQ charge transfer complex nanowire as ultra high responsivity photo-detector.  

PubMed

We report ultra large photo responsivity ? (ratio of photo-generated current to absorbed power) in a single nanowire (NW) device made from a single strand of a nanowire (diameter ~30nm and length ~200nm) of an organomettalic semiconducting charge transfer complex material of CuTCNQ. The device shows responsivity of 8x10(4) A/Watt at 1 volt applied bias with an enhancement over the dark current exceeding 10(5) at zero bias. The observed photo current has a spectral dependence that strongly follows the main absorption peak (close to 405 nm) showing the primary role of absorbed photo-generated carriers. PMID:24663833

Basori, Rabaya; Das, K; Kumar, Prashant; Narayan, K S; Raychaudhuri, A K

2014-03-10

127

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

PubMed

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

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

2010-09-01

128

Beneficial effect of melatonin on blastocyst in vitro production from heat-stressed bovine oocytes.  

PubMed

Melatonin may play an important role in protecting gametes and embryos from the potential harmful effects of oxidative stress. In this study, we first examined two different heat stress (HS) treatments for in vitro oocyte maturation (Experiment 1: 38.5 vs 41.0°C, during the first 20 h; Experiment 2: 38.5 vs 41.5°C, during the entire period) on bovine oocyte maturation and embryo development. Second, we tested different melatonin concentrations added to the maturation and culture medium (Experiment 3: 0, 10(-12) , 10(-9) , 10(-4)  m; Experiment 4: 0, 10(-3)  m), both with and without HS (38.5 or 41.5°C, respectively). In Experiment 1, the HS treatment resulted in a lower maturation rate and number of cells/blastocyst (C/B) and a higher blastocyst rate than that in the control group. In Experiment 2, oocytes/embryos from heat-stressed oocytes (HSO) had a lower maturation, cleavage and blastocyst rates, as well as a lower C/B compared with the control. In Experiment 3, in HSO groups, 10(-4)  m melatonin resulted in an increased blastocyst rate compared with 0 m melatonin, with a similar blastocyst rate to the non-HSO without melatonin. Melatonin did not have any effect in embryos from non-HSO groups compared with the control. In Experiment 4, 10(-3)  m melatonin produced lower cleavage and blastocyst rates in HSO and lower blastocyst rate in non-HSO when compared to melatonin-untreated oocytes/embryos. In conclusion, 10(-4)  m melatonin was found to alleviate bovine oocytes from the harmful effects of HS. PMID:23458773

Cebrian-Serrano, A; Salvador, I; Raga, E; Dinnyes, A; Silvestre, M A

2013-10-01

129

Energy transfer from a homopolar generator to a single turn coil toroidal field magnet  

Microsoft Academic Search

Summary form only given. The designs of busbars and switches for efficiently transferring energy to the IGNITEX single-turn tokamak and to the IGNITEX Technology Demonstrator (ITD) are presented. Unlike the full-scale IGNITEX, the ITD experiment requires fast closing switches. A coaxial switch is integrated into a coaxial\\/flat-plate transition in each busbar. The switch operates when an explosive cord propels an

R. L. Sledge; G. W. Brunson; W. A. Walls; M. D. Werst; W. F. Weldon

1990-01-01

130

Method of calculating gas dynamics and heat transfer in single stage refrigeration units  

NASA Technical Reports Server (NTRS)

A generalized mathematical model of gas-dynamic and heat transfer processes in single-stage regenerative installations operating in Stirling, MacMahon, Gifford-MacMahon, and pulsating tube cycles is proposed. A numerical method os solving initial equations on a digital computer is given. This makes it possible to calculate the change in the thermodynamic parameters in the working cycle in different machine components, as well as the dependence of cold productivity on the temperature level in the steady regime.

Zhitomirskiy, I. S.; Popolskiy, A. B.

1974-01-01

131

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

132

Natural convection heat transfer from a single and multiple heated thin cylinders in water  

NASA Astrophysics Data System (ADS)

Natural convection heat transfer from a single heated cylinder and three heated cylinders in an assembly of nine cylinders immersed in water is investigated at different heat flux values. The thin cylinders are assembled in three by three array of square pitch having a pitch to diameter ratio of 2. Empirical correlations for the overall Nusselt number versus average modified Rayleigh number are obtained and compared to the literature's correlations.

Khalifa, Abdul Jabbar N.; Hussien, Zaid Ali

2015-02-01

133

Distance Dependence of the Energy Transfer Rate from a Single Semiconductor Nanostructure to Graphene  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

134

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

2013-11-01

135

Caprine blastocyst development after in vitro fertilization with spermatozoa frozen in different extenders.  

PubMed

The feasibility of using frozen-thawed semen in caprine IVF outside the breeding season was investigated. Electroejaculated spermatozoa from a Nubian buck were washed twice and then frozen in skim milk- or in egg yolk-based extenders. Goat oocytes were matured and inseminated by frozen-thawed spermatozoa selected by swim-up. In vitro fertilization was performed in a modified defined medium (mDM), altered experimentally, for 24 h. Embryos were cultured in 50 microL of c-SOF + NEA for 9 d. The percentages of oocytes exposed to heparin-capacitated spermatozoa, (previously cryopreserved in skim milk-based extender) that cleaved, reached morula, blastocyst and expanded blastocyst stages were 82.8, 57.1, 35.7 and 30.0%, respectively. Without heparin treatment the rates for cleavage, morula, blastocyst and expanded blastocyst stages were 44.3, 31.4, 18.6 and 8.6%, respectively. Therefore, heparin treatment was included in sperm capacitation. Use of spermatozoa with BSA in the IVF medium yielded no cleavage. Although extenders containing 8 to 20% egg yolk enabled good sperm motility after cryopreservation, in vitro fertilizing ability was compromised under our conditions. By contrast, semen commercially processed in season in an egg yolk-based diluent remained effective for IVF. The highest proportion of blastocysts resulted from the use of spermatozoa diluted in a skim milk extender, heparin capacitation, and insemination in medium containing lamb serum. PMID:10732064

Keskintepe, L; Simplicio, A A; Brackett, B G

1998-05-01

136

In vivo quantitative noninvasive imaging of gene transfer by single-photon emission computerized tomography.  

PubMed

Systems aimed at detecting gene expression noninvasively in vivo are desirable for evaluating the outcome of gene transfer in clinical trials. Several approaches have been exploited using magnetic resonance imaging and spectroscopy ((31)P MRS), positron emission tomography (PET), single-photon emission tomography (SPECT), and detection of bioluminescent signals. An ideal system is based on transfer of a marker gene, the activity of which can be detected against a background from the target tissue without interfering with normal physiology or eliciting an immune response. The majority of approaches described to date use genes encoding a nonmammalian protein that can elicit immune responses or a transmembrane receptor as a marker gene whose ectopic expression may cause aberrant signaling in the target cell through binding to endogenous ligands. The dopamine transporter (DAT) is normally expressed at high levels, mainly in the dopaminergic neurons of the central nervous system. We previously synthesized a radioactive ligand, [(99m)Tc]TRODAT-1, that binds with high affinity to the dopamine transporter, allowing for SPECT imaging of the striatum in normal control subjects and individuals affected with Parkinson's disease. Here we describe a strategy to monitor gene transfer based on adeno-associated viral vector (AAV)-mediated transduction of DAT in murine muscle followed by [(99m)Tc]TRODAT-1 imaging by SPECT of cells expressing the transgene. We show that quantitative, noninvasive imaging of gene transfer is successfully achieved in vivo, using a single-photon computed tomography camera. This system employs a reporter gene encoding a mammalian protein that is absent in most tissues, has no enzymatic activity, and does not activate intracellular pathways. This should be useful to monitor gene transfer in the settings of gene therapy. PMID:12639305

Auricchio, Alberto; Acton, Paul D; Hildinger, Markus; Louboutin, Jean-Pierre; Plössl, Karl; O'Connor, Erin; Kung, Hank F; Wilson, James M

2003-02-10

137

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

138

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

PubMed

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

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

2015-01-14

139

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

PubMed Central

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

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

2014-01-01

140

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

141

Charge transfer structure-reactivity dependence of fullerene-single-walled carbon nanotube heterojunctions.  

PubMed

Charge transfer at the interface between single-walled carbon nanotubes (SWCNTs) of distinct chiral vectors and fullerenes of various molecular weights is of interest both fundamentally and because of its importance in emerging photovoltaic and optoelectronic devices. One approach for generating isolated, discretized fullerene-SWCNT heterojunctions for spectroscopic investigation is to form an amphiphile, which is able to disperse the latter at the single-SWCNT level in aqueous solution. Herein, we synthesize a series of methanofullerene amphiphiles, including derivatives of C60, C70, and C84, and investigated their electron transfer with SWCNT of specific chirality, generating a structure-reactivity relationship. In the cases of two fullerene derivatives, lipid-C61-polyethylene glycol (PEG) and lipid-C71-PEG, band gap dependent, incomplete quenching was observed across all SWCNT species, indicating that the driving force for electron transfer is small. This is further supported by a variant of Marcus theory, which predicts that the energy offsets between the nanotube conduction bands and the C61 and C71 LUMO levels are less than the exciton binding energy in SWCNT. In contrast, upon interfacing nanotubes with C85 methanofullerene, a complete quenching of all semiconducting SWCNT is observed. This enhancement in quenching efficiency is consistent with the deeper LUMO level of C85 methanofullerene in comparison with the smaller fullerene adducts, and suggests its promise as for SWCNT-fullerene heterojunctions. PMID:23848070

Hilmer, Andrew J; Tvrdy, Kevin; Zhang, Jingqing; Strano, Michael S

2013-08-14

142

Ultrafast spectroscopic signature of charge transfer between single-walled carbon nanotubes and C60.  

PubMed

The time scales for interfacial charge separation and recombination play crucial roles in determining efficiencies of excitonic photovoltaics. Near-infrared photons are harvested efficiently by semiconducting single-walled carbon nanotubes (SWCNTs) paired with appropriate electron acceptors, such as fullerenes (e.g., C60). However, little is known about crucial photochemical events that occur on femtosecond to nanosecond time scales at such heterojunctions. Here, we present transient absorbance measurements that utilize a distinct spectroscopic signature of charges within SWCNTs, the absorbance of a trion quasiparticle, to measure both the ultrafast photoinduced electron transfer time (?pet) and yield (?pet) in photoexcited SWCNT–C60 bilayer films. The rise time of the trion-induced absorbance enables the determination of the photoinduced electron transfer (PET) time of ?pet ? 120 fs, while an experimentally determined trion absorbance cross section reveals the yield of charge transfer (?pet ? 38 ± 3%). The extremely fast electron transfer times observed here are on par with some of the best donor:acceptor pairs in excitonic photovoltaics and underscore the potential for efficient energy harvesting in SWCNT-based devices. PMID:25019648

Dowgiallo, Anne-Marie; Mistry, Kevin S; Johnson, Justin C; Blackburn, Jeffrey L

2014-08-26

143

Lactate production by the mammalian blastocyst: Manipulating the microenvironment for uterine implantation and invasion?  

PubMed

The mammalian blastocyst exhibits a high capacity for aerobic glycolysis, a metabolic characteristic of tumours. It has been considered that aerobic glycolysis is a means to ensure a high carbon flux to fulfil biosynthetic demands. Here, alternative explanations for this pattern of metabolism are considered. Lactate creates a microenvironment of low pH around the embryo to assist the disaggregation of uterine tissues to facilitate trophoblast invasion. Further it is proposed that lactate acts as a signalling molecule (especially at the reduced oxygen tension present at implantation) to elicit bioactive VEGF recruitment from uterine cells, to promote angiogenesis. Finally it is suggested that the region of high lactate/low pH created by the blastocyst modulates the activity of the local immune response, helping to create immune tolerance. Consequently, the mammalian blastocyst offers a model to study the role of microenvironments, and how metabolites and pH are used in signalling. PMID:25619853

Gardner, David K

2015-04-01

144

Low female birth weight and advanced maternal age programme alterations in next-generation blastocyst development.  

PubMed

Low birth weight is associated with an increased risk for adult disease development with recent studies highlighting transmission to subsequent generations. However, the mechanisms and timing of programming of disease transmission to the next generation remain unknown. The aim of this study was to examine the effects of low birth weight and advanced maternal age on second-generation preimplantation blastocysts. Uteroplacental insufficiency or sham surgery was performed in late-gestation WKY pregnant rats, giving rise to first-generation (F1) restricted (born small) and control offspring respectively. F1 control and restricted females, at 4 or 12 months of age, were naturally mated with normal males. Second-generation (F2) blastocysts from restricted females displayed reduced expression of genes related to growth compared with F2 control (P<0.05). Following 24?h culture, F2 restricted blastocysts had accelerated development, with increased total cell number, a result of increased trophectoderm cells compared with control (P<0.05). There were alterations in carbohydrate and serine utilisation in F2 restricted blastocysts and F2 restricted outgrowths from 4-month-old females respectively (P<0.05). F2 blastocysts from aged restricted females were developmentally delayed at retrieval, with reduced total cell number attributable to reduced trophectoderm number with changes in carbohydrate utilisation (P<0.05). Advanced maternal age resulted in alterations in a number of amino acids in media obtained from F2 blastocyst outgrowths (P<0.05). These findings demonstrate that growth restriction and advanced maternal age can alter F2 preimplantation embryo physiology and the subsequent offspring growth. PMID:25667431

Master, Jordanna S; Thouas, George A; Harvey, Alexandra J; Sheedy, John R; Hannan, Natalie J; Gardner, David K; Wlodek, Mary E

2015-05-01

145

Globin Gene Expression Is Reprogrammed in Chimeras Generated by Injecting Adult Hematopoietic Stem Cells into Mouse Blastocysts  

Microsoft Academic Search

To elucidate whether the differentiation capacity of hematopoietic stem cells (HSCs) is influenced by specific microenvironments, adult mouse bone marrow–derived HSCs were injected into mouse blastocysts. Embryos developing from injected blastocysts contained donor-derived cells at various developmental stages, and progeny of the stem cells were detected in hematopoietic tissues. Thus, HSCs derived from an adult animal survive after injection into

Hartmut Geiger; Stefanie Sick; Constanze Bonifer; Albrecht M Müller

1998-01-01

146

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

PubMed

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

Bianchi, Enrica; Geremia, Raffaele; Sette, Claudio

2010-07-01

147

Tutorial on single- and two-component two-phase flow and heat transfer: Commonality and difference  

Microsoft Academic Search

It is assessed to what extent the results of two-phase two-component flow and heat transfer research can be usefully applied to support research on the flow and heat transfer in two-phase single-component systems. The latter single-component two-phase systems, envisaged for spacecraft thermal control applications, are Mechanically Pumped and Vapor Pressure Driven Loops, Capillary Pumped Loops, and Loop Heat Pipes. In

A. A. M. Delil

2002-01-01

148

On the charge transfer between single-walled carbon nanotubes and graphene  

NASA Astrophysics Data System (ADS)

It is important to understand the electronic interaction between single-walled carbon nanotubes (SWNTs) and graphene in order to use them efficiently in multifunctional hybrid devices. Here, we deposited SWNT bundles on graphene-covered copper and SiO2 substrates by chemical vapor deposition and investigated the charge transfer between them by Raman spectroscopy. Our results revealed that, on both copper and SiO2 substrates, graphene donates electrons to the SWNTs, resulting in p-type doped graphene and n-type doped SWNTs.

Rao, Rahul; Pierce, Neal; Dasgupta, Archi

2014-08-01

149

Single scattering solution for radiative transfer through Rayleigh and aerosol atmosphere  

NASA Technical Reports Server (NTRS)

A solution is presented to the radiative transfer of the solar irradiation through a turbid atmosphere, based on the single-scattering approximation, i.e., an assumption that a photon that underwent scattering either leaves the top of the atmosphere or strikes the surface. The solution depends on a special idealization of the scattering phase function of the aerosols. The equations developed are subsequently applied to analyze quantitatively the enhancement of the surface irradiation and the enhancement of the scattered radiant emittance as seen from above the atmosphere, caused by the surface reflectance and atmospheric back scattering. An order of magnitude error analysis is presented.

Otterman, J.

1977-01-01

150

On the charge transfer between single-walled carbon nanotubes and graphene  

SciTech Connect

It is important to understand the electronic interaction between single-walled carbon nanotubes (SWNTs) and graphene in order to use them efficiently in multifunctional hybrid devices. Here, we deposited SWNT bundles on graphene-covered copper and SiO{sub 2} substrates by chemical vapor deposition and investigated the charge transfer between them by Raman spectroscopy. Our results revealed that, on both copper and SiO{sub 2} substrates, graphene donates electrons to the SWNTs, resulting in p-type doped graphene and n-type doped SWNTs.

Rao, Rahul, E-mail: rrao@honda-ri.com; Pierce, Neal; Dasgupta, Archi [Honda Research Institute USA, Columbus, Ohio 43212 (United States)

2014-08-18

151

Drug transport mechanism of P-glycoprotein monitored by single molecule fluorescence resonance energy transfer  

E-print Network

In this work we monitor the catalytic mechanism of P-glycoprotein (Pgp) using single-molecule fluorescence resonance energy transfer (FRET). Pgp, a member of the ATP binding cassette family of transport proteins, is found in the plasma membrane of animal cells where it is involved in the ATP hydrolysis driven export of hydrophobic molecules. When expressed in the plasma membrane of cancer cells, the transport activity of Pgp can lead to the failure of chemotherapy by excluding the mostly hydrophobic drugs from the interior of the cell. Despite ongoing effort, the catalytic mechanism by which Pgp couples MgATP binding and hydrolysis to translocation of drug molecules across the lipid bilayer is poorly understood. Using site directed mutagenesis, we have introduced cysteine residues for fluorescence labeling into different regions of the nucleotide binding domains (NBDs) of Pgp. Double-labeled single Pgp molecules showed fluctuating FRET efficiencies during drug stimulated ATP hydrolysis suggesting that the NBD...

Ernst, Stefan; Zarrabi, Nawid; Wilkens, Stephan; Boersch, Michael

2011-01-01

152

Stress transfer in microdroplet tensile test: PVC-coated and uncoated Kevlar-29 single fiber  

NASA Astrophysics Data System (ADS)

The single fiber/microdroplet tensile test is applied for evaluating the interfacial mechanics between a fiber and a resin substrate. It is used to investigate the influence of a polymer coating on a Kevlar-29 fiber surface, specifically the stress transfer between the fiber and epoxy resin in a microdroplet. Unlike usual tests, this new test ensures a symmetrical axial stress on the embedded fiber and reduces the stress singularity that appears at the embedded fiber entry. Using a homemade loading device, symmetrical tensile tests are performed on a Kevlar-29 fiber with or without polyvinylchloride (PVC) coating, the surface of which is in contact with two epoxy resin microdroplets during curing. Raman spectra on the embedded fiber are recorded by micro-Raman Spectroscopy under different strain levels. Then they are transformed to the distributions of fiber axis stress based on the relationship between stress and Raman shift. The Raman results reveal that the fiber axial stresses increase with the applied loads, and the antisymmetric interfacial shear stresses, obtained by a straightforward balance of shear-to-axial forces argument, lead to the appearance of shear stress concentrations at a distance to the embedded fiber entry. The load is transferred from the outer fiber to the embedded fiber in the epoxy microdroplet. As is observed by scanning electronic microscopy (SEM), the existence of a flexible polymer coating on the fiber surface reduces the stress transfer efficiency.

Zhenkun, Lei; Quan, Wang; Yilan, Kang; Wei, Qiu; Xuemin, Pan

2010-11-01

153

Violation of the single-parameter scaling hypothesis in human chromosome 22 with charge transfer models  

NASA Astrophysics Data System (ADS)

We investigate transport properties of DNA sequences in human chromosome 22 and compare the results with those of a random artificial DNA sequence based on the single- and double-stranded charge transfer models. The statistical quantities, including the Hurst exponent, the distribution of Lyapunov exponent (LE), the central moments, and the scaling parameter, are numerically calculated by using the transfer-matrix approach. It is found that the existence of satellite DNA segments in human chromosome 22 could result in deviations from usual Gaussian distribution of LE. Our results suggest that the presence of the satellite DNA segments, together with the long-range correlations and the base-pairing correlations could lead to the violation of single-parameter scaling hypothesis which holds for the random artificial DNA sequence although the behaviors of the averaged LEs for both DNA sequences are similar. This provides a viewpoint to analyze differences between the genomic DNA sequences and the nonliving random ones on the basis of localization properties of wave functions in the sequences.

Guo, Ai-Min; Xiong, Shi-Jie

2009-04-01

154

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

155

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. PMID:14499003

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

2003-01-01

156

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

157

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. PMID:23126590

2012-01-01

158

FGF4-DEPENDENT STEM CELLS DERIVED FROM RAT BLASTOCYSTS DIFFERENTIATE ALONG THE TROPHOBLAST LINEAGE  

PubMed Central

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 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.

2011-01-01

159

Derivation and transcriptional profiling analysis of pluripotent stem cell lines from rat blastocysts  

Microsoft Academic Search

Embryonic stem (ES) cells are derived from blastocyst-stage embryos. Their unique properties of self-renewal and pluripotency make them an attractive tool for basic research and a potential cell resource for therapy. ES cells of mouse and human have been successfully generated and applied in a wide range of research. However, no genuine ES cell lines have been obtained from rat

Chunliang Li; Ying Yang; Junjie Gu; Yu Ma; Ying Jin

2009-01-01

160

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

Microsoft Academic Search

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

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

2000-01-01

161

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

162

Impact of blastocyst biopsy and comprehensive chromosome screening technology on preimplantation genetic screening: a systematic review of randomized controlled trials.  

PubMed

Embryonic aneuploidy is highly prevalent in IVF cycles and contributes to decreased implantation rates, IVF cycle failure and early pregnancy loss. Preimplantation genetic screening (PGS) selects the most competent (euploid) embryos for transfer, and has been proposed to improve IVF outcomes. Use of PGS with fluorescence-in-situ hybridization technology after day 3 embryo biopsy (PGS-v1) significantly lowers live birth rates and is not recommended for use. Comprehensive chromosome screening technology, which assesses the whole chromosome complement, can be achieved using different genetic platforms. Whether PGS using comprehensive chromosome screening after blastocyst biopsy (PGS-v2) improves IVF outcomes remains to be determined. A systematic review of randomized controlled trials was conducted on PGS-v2. Three trials met full inclusion criteria, comparing PGS-v2 and routine IVF care. PGS-v2 is associated with higher clinical implantation rates, and higher ongoing pregnancy rates when the same number of embryos is transferred in both PGS and control groups. Additionally, PGS-v2 improves embryo selection in eSET practice, maintaining the same ongoing pregnancy rates between PGS and control groups, while sharply decreasing multiple pregnancy rates. These results stem from good-prognosis patients undergoing IVF. Whether these findings can be extrapolated to poor-prognosis patients with decreased ovarian reserve remains to be determined. PMID:25599824

Dahdouh, Elias M; Balayla, Jacques; García-Velasco, Juan Antonio

2015-03-01

163

Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N]+.e- and [Ca24Al28O64]4+.4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+.e- with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64]4+.4e- due to the higher electron concentration (1.3 × 1022 cm-3) and mobility (~200 cm2 V-1 s-1 at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46 000 (14.8 mA cm-2) at 2 V ?m-1 (3.5 wt% [Ca2N]+.e-) with a turn-on voltage of 0.85 V ?m-1.A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N]+.e- and [Ca24Al28O64]4+.4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+.e- with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64]4+.4e- due to the higher electron concentration (1.3 × 1022 cm-3) and mobility (~200 cm2 V-1 s-1 at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46 000 (14.8 mA cm-2) at 2 V ?m-1 (3.5 wt% [Ca2N]+.e-) with a turn-on voltage of 0.85 V ?m-1. Electronic supplementary information (ESI) available: The acronyms of base materials and synthesized specimens, field emission characteristics of PSWNT-Ag paste and HSWNT-Ag paste, additional XPS and Raman data, estimation of transferred electrons from electrides to nanotubes, optical images of C12A7:e--HSWNT films, a SEM image of the tape-activated PSWNT-Ag paste, and comparison of field emission properties. See DOI: 10.1039/c4nr01629g

Menamparambath, Mini Mol; Park, Jong-Ho; Yoo, Ho-Sung; Patole, Shashikant P.; Yoo, Ji-Beom; Kim, Sung Wng; Baik, Seunghyun

2014-07-01

164

Effects of partial or complete laser-assisted hatching on the hatching of mouse blastocysts and their cell numbers  

PubMed Central

Background It is still debatable whether a full-thickness assisted hatching (AH) is better than the partial zona thinning. In this research, we used a mouse model to study the effect of partial and complete laser-AH on the rate of completely hatched blastocyst and their cell numbers. Methods In experiment 1, mouse morulae had 0, 1, 2 or 3 full-thickness openings of 10 microns created in the zona pellucida with an infrared laser beam. In the second experiment, 0, 1 and 2 openings of 20 microns were studied. In the third experiment, a full-thickness opening of 20 microns or quarter-thinning of the zonal circumference to a depth of 90% was compared with non-AH controls. Results No difference in blastocyst formation was found in laser-treated groups and in the controls. In experiment 1, the rate of completely hatched blastocysts was significantly lower than the controls. In experiment 2 when the size of the opening was increased, blastocysts completely hatched at a significantly higher rate than that in the controls. In experiment 3, the rate of completely hatched blastocysts was the highest in the full-thickness group. Cell numbers in completely hatched blastocysts from both AH groups were significantly fewer than those in the controls. Conclusions Full-thickness opening resulted in a higher rate of completely hatched blastocysts than quarter zonal-thinning and controls, but the cell numbers were significantly decreased. PMID:23510434

2013-01-01

165

Completely ES Cell-Derived Mice Produced by Tetraploid Complementation Using Inner Cell Mass (ICM) Deficient Blastocysts  

PubMed Central

Tetraploid complementation is often used to produce mice from embryonic stem cells (ESCs) by injection of diploid (2n) ESCs into tetraploid (4n) blastocysts (ESC-derived mice). This method has also been adapted to mouse cloning and the derivation of mice from induced pluripotent stem (iPS) cells. However, the underlying mechanism(s) of the tetraploid complementation remains largely unclear. Whether this approach can give rise to completely ES cell-derived mice is an open question, and has not yet been unambiguously proven. Here, we show that mouse tetraploid blastocysts can be classified into two groups, according to the presence or absence of an inner cell mass (ICM). We designate these as type a (presence of ICM at blastocyst stage) or type b (absence of ICM). ESC lines were readily derived from type a blastocysts, suggesting that these embryos retain a pluripotent epiblast compartment; whereas the type b blastocysts possessed very low potential to give rise to ESC lines, suggesting that they had lost the pluripotent epiblast. When the type a blastocysts were used for tetraploid complementation, some of the resulting mice were found to be 2n/4n chimeric; whereas when type b blastocysts were used as hosts, the resulting mice are all completely ES cell-derived, with the newborn pups displaying a high frequency of abdominal hernias. Our results demonstrate that completely ES cell-derived mice can be produced using ICM-deficient 4n blastocysts, and provide evidence that the exclusion of tetraploid cells from the fetus in 2n/4n chimeras can largely be attributed to the formation of ICM-deficient blastocysts. PMID:24733255

Wen, Duancheng; Saiz, Nestor; Rosenwaks, Zev; Hadjantonakis, Anna-Katerina; Rafii, Shahin

2014-01-01

166

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

167

Single-Walled Carbon Nanotubes Alter Cytochrome C Electron Transfer and Modulate Mitochondrial Function  

PubMed Central

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 to 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 (MMP) 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, which intensity increased as pH increase. 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 provided novel understanding to the disruption of SWCNTs to the mitochondria 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

2013-01-01

168

Single-Phase Laminar-Flow Heat Transfer and Two-Phase Oscillating-Flow Heat Transport in Microchannels  

Microsoft Academic Search

This article focuses on the research field of heat transfer of single-phase laminar flow and two-phase self-exciting oscillating flow in microchannels. First, to make prominent the special features of microthermal systems, the definition of the term “nanothermal systems” is discussed from the viewpoint of local equilibrium. Next, to show the special features of flow and heat transfer in microchannels, some

Shigefumi Nishio

2004-01-01

169

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

SciTech Connect

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

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

2014-04-14

170

Toward automated denoising of single molecular Fo?rster resonance energy transfer data.  

PubMed

A wide-field two-channel fluorescence microscope is a powerful tool as it allows for the study of conformation dynamics of hundreds to thousands of immobilized single molecules by Fo?rster resonance energy transfer (FRET) signals. To date, the data reduction from a movie to a final set containing meaningful single-molecule FRET (smFRET) traces involves human inspection and intervention at several critical steps, greatly hampering the efficiency at the post-imaging stage. To facilitate the data reduction from smFRET movies to smFRET traces and to address the noise-limited issues, we developed a statistical denoising system toward fully automated processing. This data reduction system has embedded several novel approaches. First, as to background subtraction, high-order singular value decomposition (HOSVD) method is employed to extract spatial and temporal features. Second, to register and map the two color channels, the spots representing bleeding through the donor channel to the acceptor channel are used. Finally, correlation analysis and likelihood ratio statistic for the change point detection (CPD) are developed to study the two channels simultaneously, resolve FRET states, and report the dwelling time of each state. The performance of our method has been checked using both simulation and real data. PMID:22352641

Lee, Hao-Chih; Lin, Bo-Lin; Chang, Wei-Hau; Tu, I-Ping

2012-01-01

171

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

PubMed Central

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

Kastantin, Mark; Schwartz, Daniel K.

2011-01-01

172

Drug transport mechanism of P-glycoprotein monitored by single molecule fluorescence resonance energy transfer  

NASA Astrophysics Data System (ADS)

In this work we monitor the catalytic mechanism of P-glycoprotein (Pgp) using single-molecule fluorescence resonance energy transfer (FRET). Pgp, a member of the ATP binding cassette family of transport proteins, is found in the plasma membrane of animal cells where it is involved in the ATP hydrolysis driven export of hydrophobic molecules. When expressed in the plasma membrane of cancer cells, the transport activity of Pgp can lead to the failure of chemotherapy by excluding the mostly hydrophobic drugs from the interior of the cell. Despite ongoing effort, the catalytic mechanism by which Pgp couples MgATP binding and hydrolysis to translocation of drug molecules across the lipid bilayer is poorly understood. Using site directed mutagenesis, we have introduced cysteine residues for fluorescence labeling into different regions of the nucleotide binding domains (NBDs) of Pgp. Double-labeled single Pgp molecules showed fluctuating FRET efficiencies during drug stimulated ATP hydrolysis suggesting that the NBDs undergo significant movements during catalysis. Duty cycle-optimized alternating laser excitation (DCO-ALEX) is applied to minimize FRET artifacts and to select the appropriate molecules. The data show that Pgp is a highly dynamic enzyme that appears to fluctuate between at least two major conformations during steady state turnover.

Ernst, S.; Verhalen, B.; Zarrabi, N.; Wilkens, S.; Börsch, M.

2011-03-01

173

Toward automated denoising of single molecular Förster resonance energy transfer data  

NASA Astrophysics Data System (ADS)

A wide-field two-channel fluorescence microscope is a powerful tool as it allows for the study of conformation dynamics of hundreds to thousands of immobilized single molecules by Förster resonance energy transfer (FRET) signals. To date, the data reduction from a movie to a final set containing meaningful single-molecule FRET (smFRET) traces involves human inspection and intervention at several critical steps, greatly hampering the efficiency at the post-imaging stage. To facilitate the data reduction from smFRET movies to smFRET traces and to address the noise-limited issues, we developed a statistical denoising system toward fully automated processing. This data reduction system has embedded several novel approaches. First, as to background subtraction, high-order singular value decomposition (HOSVD) method is employed to extract spatial and temporal features. Second, to register and map the two color channels, the spots representing bleeding through the donor channel to the acceptor channel are used. Finally, correlation analysis and likelihood ratio statistic for the change point detection (CPD) are developed to study the two channels simultaneously, resolve FRET states, and report the dwelling time of each state. The performance of our method has been checked using both simulation and real data.

Lee, Hao-Chih; Lin, Bo-Lin; Chang, Wei-Hau; Tu, I.-Ping

2012-01-01

174

Transfers  

Microsoft Academic Search

In this paper I develop a positive theory of intergenerational transfers. I argue that transfers are a means to induce retirement. that is, to buy the elderly out of the labor force. The reason why societies choose to do such a thing is that aggregate output is higher if the elderly do not work. I model this idea through positive

Xavier Sala-i-Martin

1992-01-01

175

Feasibility of dry cask-to-cask and pool-to-cask spent fuel transfer based on single-element transfer cask experience  

SciTech Connect

Spent fuel transportation casks and canister-based storage systems are generally loaded underwater in a nuclear plant`s spent fuel pool/cask loading pit. Several reasons exist for exploring the feasibility of dry cask-to-cask and pool-to-cask spent fuel transfer. These include: the accommodation of plants which do not have sufficient crane capacity to handle large 90 tonne (100 ton) storage canisters or shipping casks, and construction of an MRS without the need for extensive hot cell facilities. In the case of DOE`s ``Multi-Purpose Canister`` (MPC) scenario, use of such a transfer system would allow all plants with adequate transport routes to use large canisters at-reactor, and those without adequate transport routes to use the MRS for loading of large canisters without the need for hot cell facilities. The dry transfer option would not only allow the use of large canisters for all fuel, but would assist DOE in meeting MRS deadlines since licensing and construction of hot-cell facilities significantly affect schedule. This paper reviews the regulatory issues and technical design considerations for a single-element dry transfer system. Also summarized are lessons learned from the TMI-2 fuel transfer system which are directly applicable to the design, testing, startup, and use of a future dry cask-to-cask or pool-to-cask transfer system.

Schmoker, D.S.; Bowser, R.C.

1993-12-31

176

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

PubMed Central

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

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

2014-01-01

177

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

SciTech Connect

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

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

1987-02-01

178

Rapid tagging of endogenous mouse genes by recombineering and ES cell complementation of tetraploid blastocysts  

PubMed Central

The construction of knockin vectors designed to modify endogenous genes in embryonic stem (ES) cells and the generation of mice from these modified cells is time consuming. The timeline of an experiment from the conception of an idea to the availability of mature mice is at least 9 months. We describe a method in which this timeline is typically reduced to 3 months. Knockin vectors are rapidly constructed from bacterial artificial chromosome clones by recombineering followed by gap-repair (GR) rescue, and mice are rapidly derived by injecting genetically modified ES cells into tetraploid blastocysts. We also describe a tandem affinity purification (TAP)/floxed marker gene plasmid and a GR rescue plasmid that can be used to TAP tag any murine gene. The combination of recombineering and tetraploid blastocyst complementation provides a means for large-scale TAP tagging of mammalian genes. PMID:15356288

Zhou, Dewang; Ren, Jin-Xiang; Ryan, Thomas M.; Higgins, N. Patrick; Townes, Tim M.

2004-01-01

179

Sequential embryo assessment outperforms investigator-driven morphological assessment at selecting a good quality blastocyst.  

PubMed

Two selection methods (morphology-only and a sequential embryo assessment algorithm) were compared within the same IVF clinic to determine which method best identifies the embryos on day 3 that will develop into the highest quality on day 5. The sequential embryo assessment algorithm was significantly better at selecting the best embryo and selecting a blastocyst compared with the morphology-only method. PMID:16500367

Neuber, Evelyn; Mahutte, Neal G; Arici, Aydin; Sakkas, Denny

2006-03-01

180

Increased MAP kinase inhibition enhances epiblast-specific gene expression in bovine blastocysts.  

PubMed

Mammalian blastocysts comprise three distinct lineages, namely, trophoblast, hypoblast, and epiblast, which develop into fetal placenta, extraembryonic yolk sac, and embryo proper, respectively. Pluripotent embryonic stem cells, capable of forming all adult cell types, can only be derived from the epiblast. In mouse and rat, this process is promoted by the double inhibition (2i) of mitogen-activated protein kinase kinase (MAP2K), which antagonizes FGF signaling, and glycogen synthase kinase 3 (GSK3), which stimulates the WNT pathway. We investigated variations of the 2i treatment on lineage segregation and pluripotency-related gene expression in bovine blastocysts. In vitro-fertilized embryos were cultured either in the presence of inhibitors of GSK3 (3 ?M CHIR) and MAP2K (0.4 vs. 10 ?M PD0325901, designated 2i and 2i+, respectively) or in 2i/2i+ with FGFR inhibitor (0.1 ?M PD173074, designated 3i [2i and PD173074] and 3i+ [2i+ and PD173074]). Compared with 2i, both 2i+ and 3i+ potentiated the improvement in blastocyst morphology. Using an automated platform for multiplexed digital mRNA profiling, we simultaneously counted transcripts of 76 candidate genes in bovine blastocysts treated with multiple kinase inhibitors. We show that 2i+ medium specifically increased FGF4 and NANOG while reducing PDGFRalpha and SOX17 levels. The shift from a hypoblast to an epiblast gene expression signature was confirmed by quantitative PCR. A wide range of functionally related genes, including candidates involved in DNA methylation, were not significantly changed. This well-defined 2i+ effect was not observed after pharmacologically inhibiting FGF receptor or related MAP kinases (p38, JNK, and ERK5). In summary, our data suggest that increased MAP2K inhibition exerts its pluripotency-promoting effects through as yet unidentified signals. PMID:25009207

McLean, Zachariah; Meng, Fanli; Henderson, Harold; Turner, Pavla; Oback, Björn

2014-08-01

181

Quantifying the Biomechanics of Conception: L-Selectin-Mediated Blastocyst Implantation Mechanics with Engineered “Trophospheres”  

PubMed Central

An estimated 12% of women in the United States suffer from some form of infertility. In vitro fertilization (IVF) is the most common treatment for infertility encompassing over 99% of all assisted reproductive technologies. However, IVF has a low success rate. Live birth rates using IVF can range from 40% in women younger than 35 years to 4% in women older than 42 years. Costs for a successful IVF outcome can be upward of $61,000. The low success rate of IVF has been attributed to the inability of the blastocyst to implant to the uterus. Blastocyst implantation is initiated by L-selectin expressing cells, trophoblasts, binding to L-selectin ligands, primarily sialyl Lewis X (sLeX), on the uterine surface endometrium. Legal and ethical considerations have limited the research on human subjects and tissues, whereas animal models are costly or do not properly mimic human implantation biochemistry. In this work, we describe a cellular model system for quantifying L-selectin adhesion mechanics. L-selectin expression was confirmed in Jeg-3, JAR, and BeWo cell lines, with only Jeg-3 cells exhibiting surface expression. Jeg-3 cells were cultured into three-dimensional spheres, termed “trophospheres,” as a mimic to human blastocysts. Detachment assays using a custom-built parallel plate flow chamber show that trophospheres detach from sLeX functionalized slides with 2.75×10?3 dyn of force and 7.5×10?5 dyn-cm of torque. This work marks the first time a three-dimensional cell model has been utilized for quantifying L-selectin binding mechanics related to blastocyst implantation. PMID:23927766

Jost, Monika; Rothstein, Dianne; Robertson, Noreen; Marcolongo, Michele S.

2014-01-01

182

Quantifying the biomechanics of conception: L-selectin-mediated blastocyst implantation mechanics with engineered "trophospheres".  

PubMed

An estimated 12% of women in the United States suffer from some form of infertility. In vitro fertilization (IVF) is the most common treatment for infertility encompassing over 99% of all assisted reproductive technologies. However, IVF has a low success rate. Live birth rates using IVF can range from 40% in women younger than 35 years to 4% in women older than 42 years. Costs for a successful IVF outcome can be upward of $61,000. The low success rate of IVF has been attributed to the inability of the blastocyst to implant to the uterus. Blastocyst implantation is initiated by L-selectin expressing cells, trophoblasts, binding to L-selectin ligands, primarily sialyl Lewis X (sLeX), on the uterine surface endometrium. Legal and ethical considerations have limited the research on human subjects and tissues, whereas animal models are costly or do not properly mimic human implantation biochemistry. In this work, we describe a cellular model system for quantifying L-selectin adhesion mechanics. L-selectin expression was confirmed in Jeg-3, JAR, and BeWo cell lines, with only Jeg-3 cells exhibiting surface expression. Jeg-3 cells were cultured into three-dimensional spheres, termed "trophospheres," as a mimic to human blastocysts. Detachment assays using a custom-built parallel plate flow chamber show that trophospheres detach from sLeX functionalized slides with 2.75 × 10(-3) dyn of force and 7.5 × 10(-5) dyn-cm of torque. This work marks the first time a three-dimensional cell model has been utilized for quantifying L-selectin binding mechanics related to blastocyst implantation. PMID:23927766

Yucha, Robert W; Jost, Monika; Rothstein, Dianne; Robertson, Noreen; Marcolongo, Michele S

2014-01-01

183

Uptake and accumulation of tritiated uteroglobin by day-6 rabbit blastocysts  

Microsoft Academic Search

Uptake of uteroglobin (UGL) by day-6 rabbit blastocysts and the intracellular fate of this protein were studied by light- and electron-microscopic autoradiography, immunocytochemistry and acid-phosphatase cytochemistry. UGL, labelled with N-succinimidyl-(2-3-3H)-propionate, was administered to embryos in vitro for 15 min to 4 h. The kinetics, determined from light-microscopic autoradiographs, showed a continuous uptake of the labeled protein over a 4-h period

D. R. Dannhorn; C. Kirchner

1990-01-01

184

Use of coisogenic host blastocysts for efficient establishment of germline chimeras with C57BL/6J ES cell lines.  

PubMed

Gene targeting in embryonic stem (ES) cells allows the production of mice with specified genetic mutations. Currently, germline-competent ES cell lines are available from only a limited number of mouse strains, and inappropriate ES cell/host blastocyst combinations often restrict the efficient production of gene-targeted mice. Here, we describe the derivation of C57BL/6J (B6) ES lines and compare the effectiveness of two host blastocyst donors, FVB/NJ (FVB) and the coisogenic strain C57BL/6-Tyr(c)-2J (c2J), for the production of germline chimeras. We found that when B6 ES cells were injected into c2J host blastocysts, a high rate of coat-color chimerism was detected, and germline transmission could be obtained with few blastocyst injections. In all but one case, highly chimeric mice transmitted to 100% of their offspring. The injection of B6 ES cells into FVB blastocysts produced some chimeric mice. However; the proportion of coat-color chimerism was low, with many more blastocyst injections required to generate chimeras capable of germline transmission. Our data support the use of the coisogenic albino host strain, c2J, for the generation of germline-competent chimeric mice when using B6 ES cells. PMID:11730008

Schuster-Gossler, K; Lee, A W; Lerner, C P; Parker, H J; Dyer, V W; Scott, V E; Gossler, A; Conover, J C

2001-11-01

185

Cryopreserved morulae can be used to efficiently generate germline-transmitting chimeras by blastocyst injection.  

PubMed

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 mice would be the utilization of cryopreserved embryos suitable for injection. C57Bl/6 morulae were frozen using a standard 2-step protocol with ethylene glycol as the cryopreservation agent. We determined that cryopreserved morulae could thaw, culture to blastocyst stage in KSOM media and survive injection at rates equivalent to control embryos. Cryopreserved morulae were also equivalent to controls at all later stages in the process of production of chimeric mice, including birth rate, percentage chimerism of resulting animals and ability to produce germline progeny. Hence, cryopreservation of morulae for blastocyst injection is a suitable option to enhance the efficiency of chimeric mouse generation. PMID:16245159

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

2005-10-01

186

Curcumin prevents methylglyoxal-induced oxidative stress and apoptosis in mouse embryonic stem cells and blastocysts.  

PubMed

Methylglyoxal (MG) is a reactive dicarbonyl compound endogenously produced mainly from glycolytic intermediates. Elevated MG levels in diabetes patients are believed to contribute to diabetic complications. MG is cytotoxic through induction of apoptosis. Curcumin, the yellow pigment of Curcuma longa, is known to have antioxidant and anti-inflammatory properties. In the present study, we examined the effect of curcumin on apoptotic biochemical events caused by incubation of ESC-B5 cells with MG. Curcumin inhibited the MG-induced DNA fragmentation, caspase-3 activation, cleavage of PARP, mitochondrial cytochrome c release, and JNK activation. Importantly, curcumin also inhibited the MG-stimulated increase of reactive oxygen species (ROS) in these cells. In addition, we demonstrated that curcumin prevented the MG-induced apoptosis of mouse blastocysts isolated from pregnant mice. Moreover, curcumin significantly reduced the MG-mediated impairment of blastocyst development from mouse morulas. The results support the hypothesis that curcumin inhibits MG-induced apoptosis in mouse ESC-B5 cells and blastocysts by blocking ROS formation and subsequent apoptotic biochemical events. PMID:15887245

Hsuuw, Yan-Der; Chang, Chen-Kang; Chan, Wen-Hsiung; Yu, Jau-Song

2005-12-01

187

An Improved Bioluminescence Resonance Energy Transfer Strategy for Imaging Intracellular Events in Single Cells and Living Subjects  

Microsoft Academic Search

Bioluminescence resonance energy transfer (BRET) is cur- rently used for monitoring various intracellular events, including protein-protein interactions, in normal and aber- rant signal transduction pathways. However, the BRET vectors currently used lackadequate sensitivity for imaging events of interest from both single living cells and small living subjects. Taking advantage of the critical relationship of BRET efficiency and donor quantum efficiency,

Abhijit De; Andreas Markus Loening; Sanjiv Sam Gambhir

2007-01-01

188

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

Microsoft Academic Search

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

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

1999-01-01

189

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies.  

PubMed

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics industry. In this technique the chip and/or the substrate is bumped and the two are bonded via these conductive bumps. Many bumping techniques have been developed and intensively investigated since the introduction of the FC technology in 1960(1) such as stencil printing, stud bumping, evaporation and electroless/electroplating(2). Despite the progress that these methods have made they all suffer from one or more than one drawbacks that need to be addressed such as cost, complex processing steps, high processing temperatures, manufacturing time and most importantly the lack of flexibility. In this paper, we demonstrate a simple and cost-effective laser-based bump forming technique known as Laser-induced Forward Transfer (LIFT)(3). Using the LIFT technique a wide range of bump materials can be printed in a single-step with great flexibility, high speed and accuracy at RT. In addition, LIFT enables the bumping and bonding down to chip-scale, which is critical for fabricating ultra-miniature circuitry. PMID:25867627

Kaur, Kamal S; Van Steenberge, Geert

2015-01-01

190

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

PubMed Central

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

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

2014-01-01

191

Quantitative correlation between defect density and heterogeneous electron transfer rate of single layer graphene.  

PubMed

Improving electrochemical activity of graphene is crucial for its various applications, which requires delicate control over its geometric and electronic structures. We demonstrate that precise control of the density of vacancy defects, introduced by Ar(+) irradiation, can improve and finely tune the heterogeneous electron transfer (HET) rate of graphene. For reliable comparisons, we made patterns with different defect densities on a same single layer graphene sheet, which allows us to correlate defect density (via Raman spectroscopy) with HET rate (via scanning electrochemical microscopy) of graphene quantitatively, under exactly the same experimental conditions. By balancing the defect induced increase of density of states (DOS) and decrease of conductivity, the optimal HET rate is attained at a moderate defect density, which is in a critical state; that is, the whole graphene sheet becomes electronically activated and, meanwhile, maintains structural integrity. The improved electrochemical activity can be understood by a high DOS near the Fermi level of defective graphene, as revealed by ab initio simulation, which enlarges the overlap between the electronic states of graphene and the redox couple. The results are valuable to promote the performance of graphene-based electrochemical devices. Furthermore, our findings may serve as a guide to tailor the structure and properties of graphene and other ultrathin two-dimensional materials through defect density engineering. PMID:25350471

Zhong, Jin-Hui; Zhang, Jie; Jin, Xi; Liu, Jun-Yang; Li, Qiongyu; Li, Mao-Hua; Cai, Weiwei; Wu, De-Yin; Zhan, Dongping; Ren, Bin

2014-11-26

192

Volume profiles of the reaction mechanism of esterase: Evidence of a single-proton-transfer mechanism  

NASA Astrophysics Data System (ADS)

The pre-steady-state kinetics of hydrolysis of p-nitrophenyl trimethylacetate (pNPT), and the steady-state kinetic of hydrolysis of N-acetyl- L-tryptophanamide (ATA), N-acetyl- L-tryptophan p-chloroanilide (ATpCA), and succinyl- L-alanyl- L-alanine p-nitroanilide (SA 3pNA), catalyzed by ?-chymotrypsin (?-CHT) have been studied in Tris buffer solution up to 2.4 kbar at 25°C. The reaction is initiated by the substrate binding, and then the acylation and deacylation occur. The volume changes ?VKs for the dissociation process of an enzyme-substrate complex, are (-14 ± 1) cm 3/mol for pNPT and (-3 ± 2) cm 3/mol for ATA. The activation volumes ?Vacyl? for the acylation process are (-24 ±1) cm 3/mol for pNPT, (10±2) cm 3/mol for ATpCA, and (15±2) cm 3/mol for SA 3pNA, respectively. The activation volume ?Vdeacyl? of the deacylation is (-2±1) cm 3/mol. From the reaction and activation volumes, it os concluded that the catalytic reaction of ?-CHT follows the single proton-transfer-mechanism.

Makimoto, S.; Taniguchi, Y.

1986-05-01

193

Troika of the mouse blastocyst: lineage segregation and stem cells.  

PubMed

The initial period of mammalian embryonic development is primarily devoted to cell commitment to the pluripotent lineage, as well as to the formation of extraembryonic tissues essential for embryo survival in utero. This phase of development is also characterized by extensive morphological transitions. Cells within the preimplantation embryo exhibit extraordinary cell plasticity and adaptation in response to experimental manipulation, highlighting the use of a regulative developmental strategy rather than a predetermined one resulting from the non-uniform distribution of maternal information in the cytoplasm. Consequently, early mammalian development represents a useful model to study how the three primary cell lineages; the epiblast, primitive endoderm (also referred to as the hypoblast) and trophoblast, emerge from a totipotent single cell, the zygote. In this review, we will discuss how the isolation and genetic manipulation of murine stem cells representing each of these three lineages has contributed to our understanding of the molecular basis of early developmental events. PMID:22023624

Artus, Jerome; Hadjantonakis, Anna-Katerina

2012-01-01

194

Troika of the Mouse Blastocyst: Lineage Segregation and Stem Cells  

PubMed Central

The initial period of mammalian embryonic development is primarily devoted to cell commitment to the pluri-potent lineage, as well as to the formation of extraembryonic tissues essential for embryo survival in utero. This phase of development is also characterized by extensive morphological transitions. Cells within the preimplantation embryo exhibit extraordinary cell plasticity and adaptation in response to experimental manipulation, highlighting the use of a regulative developmental strategy rather than a predetermined one resulting from the non-uniform distribution of maternal information in the cytoplasm. Consequently, early mammalian development represents a useful model to study how the three primary cell lineages; the epiblast, primitive endoderm (also referred to as the hypoblast) and trophoblast, emerge from a totipotent single cell, the zygote. In this review, we will discuss how the isolation and genetic manipulation of murine stem cells representing each of these three lineages has contributed to our understanding of the molecular basis of early developmental events. PMID:22023624

Artus, Jérôme; Hadjantonakis, Anna-Katerina

2012-01-01

195

Facile electrochemical transfer of large-area single crystal epitaxial graphene from Ir(1?1?1)  

NASA Astrophysics Data System (ADS)

High-quality growth of graphene and subsequent reliable transfer to insulating substrates are needed for various technological applications, such as flexible screens and high speed electronics. In this paper, we present a new electrochemical method for the transfer of large-area, high-quality single crystalline graphene from Ir(1?1?1) to Si/SiO2 under ambient conditions. The method is based on intercalation of tetraoctylammonium ions between the graphene layer and the Ir surface. This simple technique allows transfer of graphene single crystals having the same size as the substrate they are grown on (diameter ?7?mm). In addition, the substrate can be reused for further growth cycles. A detailed Raman map analysis of the transferred graphene reveals straight lines, in which the Raman peaks characteristic for graphene are shifted. These lines originate from scratches in the Ir(1?1?1) crystal introduced by the polishing procedure. Furthermore, areas with numerous wrinkles exist inbetween these lines, forming a network across the entire graphene crystal. Hence, the initial characteristics and imprints left on the sheet of graphene in terms of strain and wrinkles from the growth process remain after transfer.

Koefoed, Line; Kongsfelt, Mikkel; Ulstrup, Søren; Grubiši? ?abo, Antonija; Cassidy, Andrew; Whelan, Patrick R.; Bianchi, Marco; Dendzik, Maciej; Pizzocchero, Filippo; Jørgensen, Bjarke; Bøggild, Peter; Hornekær, Liv; Hofmann, Philip; Pedersen, Steen U.; Daasbjerg, Kim

2015-03-01

196

Skill transfer from symmetric and asymmetric bimanual training using a robotic system to single limb performance  

PubMed Central

Background Humans are capable of fast adaptation to new unknown dynamics that affect their movements. Such motor learning is also believed to be an important part of motor rehabilitation. Bimanual training can improve post-stroke rehabilitation outcome and is associated with interlimb coordination between both limbs. Some studies indicate partial transfer of skills among limbs of healthy individuals. Another aspect of bimanual training is the (a)symmetry of bimanual movements and how these affect motor learning and possibly post-stroke rehabilitation. Methods A novel bimanual 2-DOF robotic system was used for both bimanual and unimanual reaching movements. 35 young healthy adults participated in the study. They were divided into 5 test groups that performed movements under different conditions (bimanual or unimanual movements and symmetric or asymmetric bimanual arm loads). The subjects performed a simple tracking exercise with the bimanual system. The exercise was developed to stimulate motor learning by applying a velocity-dependent disturbance torque to the handlebar. Each subject performed 255 trials divided into three phases: baseline without disturbance torque, training phase with disturbance torque and evaluation phase with disturbance torque. Results Performance was assessed with the maximal values of rotation errors of the handlebar. After exposure to disturbance torque, the errors decreased for both unimanual and bimanual training. Errors in unimanual evaluation following the bimanual training phase were not significantly different from errors in unimanual evaluation following unimanual training. There was no difference in performance following symmetric or asymmetric training. Changing the arm force symmetry during bimanual movements from asymmetric to symmetric had little influence on performance. Conclusions Subjects could adapt to an unknown disturbance torque that was changing the dynamics of the movements. The learning effect was present during both unimanual and bimanual training. Transfer of learned skills from bimanual training to unimanual movements was also observed, as bimanual training also improved single limb performance with the dominant arm. Changes of force symmetry did not have an effect on motor learning. As motor learning is believed to be an important mechanism of rehabilitation, our findings could be tested for future post-stroke rehabilitation systems. PMID:22805223

2012-01-01

197

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. PMID:23300778

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

198

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

2010-05-01

199

Single breath xenon polarization transfer contrast (SB-XTC): implementation and initial results in healthy humans  

PubMed Central

Purpose To implement and characterize a single-breath xenon transfer contrast (SB-XTC) method to assess the fractional diffusive gas transport F in the lung: to study the dependence of F and its uniformity as a function of lung volume; to estimate local alveolar surface area per unit gas volume SA/VGas from multiple diffusion time measurements of F; to evaluate the reproducibility of the measurements and the necessity of B1 correction in cases of centric and sequential encoding. Materials and Methods In SB-XTC three or four gradient echo images separated by inversion/saturation pulses were collected during a breath-hold in eight healthy volunteers, allowing the mapping of F (thus SA/VGas) and correction for other contributions such as T1 relaxation, RF depletion and B1 inhomogeneity from inherently registered data. Results Regional values of F and its distribution were obtained; both the mean value and heterogeneity of F increased with the decrease of lung volume. Higher values of F in the bases of the lungs in supine position were observed at lower volumes in all volunteers. Local SA/VGas (with a mean ± standard deviation of SA/VGas¯=89±30cm-1) was estimated in vivo near functional residual capacity. Calibration of SB-XTC on phantoms highlighted the necessity for B1 corrections when k-space is traversed sequentially; with centric ordering B1 distribution correction is dispensable. Conclusion SB-XTC technique is implemented and validated for in vivo measurements of local SA/VGas. PMID:23011916

Muradyan, Iga; Butler, James P; Dabaghyan, Mikayel; Hrovat, Mirko; Dregely, Isabel; Ruset, Iulian; Topulos, George P; Frederick, Eric; Hatabu, Hiroto; Hersman, William F; Patz, Samuel

2012-01-01

200

The Effect of Single Embryo Transfer on Perinatal Outcomes in Japan  

PubMed Central

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

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

2015-01-01

201

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

PubMed Central

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

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

2014-01-01

202

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

NASA Technical Reports Server (NTRS)

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

Miyoshi, K.; Buckley, D. H.

1978-01-01

203

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

2012-10-23

204

Single-phase heat transfer and pressure drop characteristics of an integral-spine-fin within an annulus  

NASA Astrophysics Data System (ADS)

The laminar, single phase heat transfer and friction characteristics of an integral-spine-fin pipe within an annulus are presented. The heat transfer coefficient was determined using a modified version of the Wilson Plot method. The test fluid was pumped through the annulus of a straight, 3 m test section. Three fluids were investigated: (1) tap water, (2) 34% ethylene glycol/water mixture, and (3) 40% ethylene glycol/water mixture. These fluids produced a significant variation in the Prandtl number so that its exponential dependence could be determined. The annulus-Reynolds numbers were varied from 100 to 1400 to obtain the Reynolds number exponent. An empirical correlation for the Nusselt number was developed which accounts for the development of the thermal boundary layer. An empirical correlation for the friction factor is also presented. It is demonstrated that the spines enhance the heat transfer through additional surface area and fluid mixing.

Kedzierski, M. A.; Kim, M. S.

1994-06-01

205

Two-photon-induced hot-electron transfer to a single molecule in a scanning tunneling microscope  

SciTech Connect

The junction of a scanning tunneling microscope (STM) operating in the tunneling regime was irradiated with femtosecond laser pulses. A photoexcited hot electron in the STM tip resonantly tunnels into an excited state of a single molecule on the surface, converting it from the neutral to the anion. The electron-transfer rate depends quadratically on the incident laser power, suggesting a two-photon excitation process. This nonlinear optical process is further confirmed by the polarization measurement. Spatial dependence of the electron-transfer rate exhibits atomic-scale variations. A two-pulse correlation experiment reveals the ultrafast dynamic nature of photoinduced charging process in the STM junction. Results from these experiments are important for understanding photoinduced interfacial charge transfer in many nanoscale inorganic-organic structures.

Wu, S. W.; Ho, W. [Department of Physics and Astronomy and Department of Chemistry, University of California, Irvine, California 92697-4575 (United States)

2010-08-15

206

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

PubMed

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

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

2013-12-01

207

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

PubMed Central

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

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

2013-01-01

208

Comparison of blastocyst and sage media for in vitro maturation of human immature oocytes.  

PubMed

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

Pongsuthirak, Pallop; Songveeratham, Sorramon; Vutyavanich, Teraporn

2015-03-01

209

Accumulation of advanced glycation end products in the rabbit blastocyst under maternal diabetes.  

PubMed

Diabetes mellitus (DM) during pregnancy is one of the leading causes of perinatal morbidity and birth defects. The mechanism by which maternal hyperglycemia, the major teratogenic factor, induces embryonic malformations remains unclear. Advanced glycation end products (AGEs) are known to accumulate during the course of DM and contribute to the development of diabetic complications. Employing a diabetic rabbit model, we investigated the influence of maternal hyperglycemia during the preimplantation period on AGE formation (pentosidine, argpyrimidine, and N(?)-carboxymethyllysine (CML)) in the reproductive tract and the embryo itself. As a consequence of type 1 DM, the AGE levels in blood plasma increased up to 50%, correlating closely with an AGE accumulation in the endometrium of diabetic females. Embryos from diabetic mothers had increased protein-bound CML levels and showed enhanced fluorescent signals for AGE-specific fluorescence in the blastocyst cavity fluid (BCF). The quantification of CML by HPLC-mass spectrometry (MS/MS) showed a higher amount of soluble CML in the BCF of blastocysts from diabetic rabbits (0.26±0.05??mol/l) compared with controls (0.18±0.02??mol/l). The high amount of AGEs in blastocysts from diabetic mothers correlates positively with an increased AGER (receptor for AGE (RAGE)) mRNA expression. Our study gives alarming insights into the consequences of poorly controlled maternal diabetes for AGE formation in the embryo. Maternal hyperglycemia during the preimplantation period is correlated with an increase in AGE formation in the uterine environment and the embryo itself. This may influence the development of the embryo through increased AGE-mediated cellular stress by RAGEs. PMID:24821834

Haucke, Elisa; Navarrete Santos, Alexander; Simm, Andreas; Henning, Christian; Glomb, Marcus A; Gürke, Jacqueline; Schindler, Maria; Fischer, Bernd; Navarrete Santos, Anne

2014-08-01

210

Intramolecular redox-active ligand-to-substrate single-electron transfer: radical reactivity with a palladium(II) complex.  

PubMed

Coordination of the redox-active tridentate NNO ligand L(H2) to Pd(II) yields the paramagnetic iminobenzosemiquinonato complex 3. Single-electron reduction of 3 yields diamagnetic amidophenolato complex 4, capable of activating aliphatic azide 5. Experimental and computational studies suggest a redox-noninnocent pathway wherein the redox-active ligand facilitates intramolecular ligand-to-substrate single-electron transfer to generate an open-shell singlet "nitrene-substrate radical, ligand radical", enabling subsequent radical-type C-H amination reactivity with Pd(II). PMID:24927362

Broere, Daniël L J; de Bruin, Bas; Reek, Joost N H; Lutz, Martin; Dechert, Sebastian; van der Vlugt, Jarl Ivar

2014-08-20

211

High Quality, Transferable Graphene Grown on Single Crystal Cu(111) Thin Films on Basal-Plane Sapphire  

Microsoft Academic Search

The current method of growing large-area graphene on Cu surfaces\\u000a(polycrystalline foils and thin films) and its transfer to arbitrary substrates\\u000ais technologically attractive. However, the quality of graphene can be improved\\u000asignificantly by growing it on single-crystal Cu surfaces. Here we show that\\u000ahigh quality, large-area graphene can be grown on epitaxial single-crystal\\u000aCu(111) thin films on reusable basal-plane

Kongara M. Reddy; Andrew D. Gledhill; Chun-Hu Chen; Julie M. Drexler; Nitin P. Padture

2010-01-01

212

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

213

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

SciTech Connect

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

Lian, Tianquan

2014-04-22

214

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

215

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

2013-08-01

216

Lysophosphatidic Acid Signaling in Late Cleavage and Blastocyst Stage Bovine Embryos  

PubMed Central

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

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

2014-01-01

217

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

PubMed

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

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

2014-12-01

218

DFT/B3LYP study of the substituent effect on the reaction enthalpies of the individual steps of single electron transfer-proton transfer and sequential proton loss electron transfer mechanisms of phenols antioxidant action.  

PubMed

The reaction enthalpies related to the individual steps of two phenolic antioxidants action mechanisms, single electron transfer-proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET), for 30 meta and para-substituted phenols (ArOH) were calculated using DFT/B3LYP method. These mechanisms represent the alternative ways to the extensively studied hydrogen atom transfer (HAT) mechanism. Except the comparison of calculated reaction enthalpies with available experimental and/or theoretical values, obtained enthalpies were correlated with Hammett constants. We have found that electron-donating substituents induce the rise in the enthalpy of proton dissociation (PDE) from ArOH+* radical cation (second step in SET-PT) and in the proton affinities of phenoxide ions ArO- (reaction enthalpy of the first step in SPLET). Electron-withdrawing groups cause the increase in the reaction enthalpies of the processes where electron is abstracted, i.e., in the ionization potentials of ArOH (first step in SET-PT) and in the enthalpy of electron transfer from ArO- (second step in SPLET). Found results indicate that all dependences of reaction enthalpies on Hammett constants of the substituents are linear. The calculations of liquid-phase reaction enthalpies for several para-substituted phenols indicate that found trends hold also in water, although substituent effects are weaker. From the thermodynamic point of view, entering SPLET mechanism represents the most probable process in water. PMID:17078630

Klein, Erik; Lukes, Vladimír

2006-11-01

219

Experimental study of single-phase pressure drop and heat transfer in a micro-fin tube  

SciTech Connect

The single-phase pressure drop and heat transfer in a micro-fin tube were measured using oil and water as the working fluids. The Prandtl number varied from 3.2 to 220 and the Reynolds number ranged from 2500 to 90,000. The results show that there is a critical Reynolds number, Re{sub cr}, for heat transfer enhancement. For Retransfer in the micro-fin tube is the same as that in a smooth tube, but for Reynolds numbers higher than Re{sub cr}, the heat transfer in the micro-fin tube is gradually enhanced compared with a smooth tube. It reaches more than twice that in a smooth tube for Reynolds numbers greater than 30,000 with water as the working fluid. The Nusselt number is proportional to Pr {sup 0.56} in the enhanced region and is proportional to Pr {sup 0.3} in the non-enhanced region. For the high Prandtl number working fluid (oil, 80< Pr <220), the critical Reynolds number for heat transfer enhancement is about 6000, while for the low Prandtl number working fluid (water, 3.2< Pr <5.8), the critical Reynolds number for heat transfer enhancement is about 10,000. The friction factors in the micro-fin tube are almost the same as for a smooth tube for Reynolds numbers below 10,000. For Reynolds numbers higher than 30,000, the friction factor is about 40-50% higher than for a smooth tube. (author)

Li, Xiao-Wei; Meng, Ji-An; Li, Zhi-Xin [School of Aerospace, Tsinghua University, Beijing 100084 (China)

2007-11-15

220

(Analysis of proteins essential for Agrobacterium mediated DNA transfer to plant cells). [Single-stranded DNA binding proteins  

SciTech Connect

The tumor inducing (Ti) plasmid of Agrobacterium contains two regions important for infection and transformation of plant cells. One region, the T-DNA, is transferred as a single strand into the plant cell, while the virulence (vir) region is responsible for recognition of susceptible cells, synthesis of the T-DNA single strand (T-strand), formation of a T-strand protein complex and transfer of this complex into susceptible cells. A DNA binding protein, VirE2, was identified as a product of the vir region. Sequencing of the 9000 kilobase pair virB region has been completed. Expression of 10 of the predicted 11 open reading frames (ORFs) was demonstrated in Escherichia coli. Translational coupling was demonstrated for 5 ORFs. Hydropathy analysis indicates that 9 of 11 ORFs have hydrophobic regions that could permit membrane channel formation. In related work, analysis of protons that potentiate movement of plant viruses was discussed, with indications that the tobacco mosaic virus (TMV) protein P30 may mediate transfer of TMV RNA through plasmadesmata. Also, using the T-DNA element as a marker, genes responsible for abnormal flower development are being cloned and isolated. 3 refs. (MHB)

Not Available

1989-12-14

221

Pressure drop and heat transfer characteristics for single-phase developing flow of water in rectangular microchannels  

NASA Astrophysics Data System (ADS)

Experiments were conducted to investigate the pressure drop and heat transfer characteristics of single-phase flow of de-ionized water in single copper microchannels of hydraulic diameters 0.438 mm, 0.561 mm and 0.635 mm. The channel length was 62 mm. The experimental conditions covered a range of mass flux from 500 to 5000 kg/m2 s in the laminar, transitional and low Reynolds number turbulent regimes. Pressure drop was measured for adiabatic flows with fluid inlet temperatures of 30°C, 60°C and 90°C. In the heat transfer tests, the heat flux ranged from 256 kW/m2 to 519 kW/m2. Friction factors and Nusselt numbers determined from the measurements were higher than for fully-developed conditions, but in reasonable agreement with predictions made using published solutions for hydrodynamically and thermally developing flow. When entrance effects, experimental uncertainties, heat losses, inlet and exit losses, thermal boundary conditions and departure from laminar flow were considered, the results indicate that equations developed for flow and heat transfer in conventional size channels are applicable for water flows in microchannels of these sizes.

Mirmanto; Kenning, D. B. R.; Lewis, J. S.; Karayiannis, T. G.

2012-11-01

222

Development of General Correlation for Heat Transfer in Single-Phase Turbulent Flow Inside Internally Helical-Grooved Tubes  

NASA Astrophysics Data System (ADS)

An experimental study of heat transfer in single-phase turbulent flow inside an internally helical-grooved tube was carried out using thirteen different kinds of grooved tubes and a smooth tube with 6.35mm outer diameter and1000mm working length. The range of geometric parameters of grooved test tubes were number of grooves (45 to 65), helix angle (10 t o 35deg.) and fm height (0.15 to 0.3 mm). In the experiments, each of test tubes was heated at constant heat input of 1.4 kW by an electric heater. The inlet cooling water temperature was kept between 16 and 18 °C, and the flow rate was varied from 0.03 to 0.11kg/s. The obtained data indicated that heat transfer coefficients were from110 to 200% higher than those of smooth tube and increased with increasing the ratio of inner surface area of grooved tube to that of smooth tube and helix angle, while decreased with increasing the number of grooves. The correlations to predict the heat transfer coefficients were developed based on the measured data, which predicted the experimental data within ±20% and correlated the data reported in literature within ±30% and the analogy between heat transfer and pressure drop for the grooved tube was discussed.

Goto, Masao; Inoue, Norihiro; Siromoto, Keiko; Emoto, Yukiyasu; Li, Yu; Sato, Masaaki; Kiyotani, Akihiro

223

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

PubMed Central

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

Park, Sang Kyu

2014-01-01

224

Two-dimensional transport and transfer of a single atomic qubit in optical tweezers  

E-print Network

that these manipulations of the external degrees of freedom preserve the coherence of the qubit, and do not induce any. An attractive architecture is a large set of physically independent qubits arranged in three spatial regions­6 . Furthermore, we transfer a qubit between two tweezers, and show that this manipulation also preserves

Loss, Daniel

225

Modelling of heat, mass and charge transfer in a PEMFC single cell  

Microsoft Academic Search

The aim of this study is the understanding of the main phenomena governing fuel cell performances. We present a fuel cell model that takes into account gas diffusion in the porous electrodes, water diffusion and electro-osmotic transport through the polymeric membrane, and heat transfer in both the Membrane Electrodes Assembly (MEA) and bipolar plates. This model is constructed by combining

J. Ramousse; J. Deseure; O. Lottin; S. Didierjean; D. Maillet

2005-01-01

226

Excited state electron transfer precedes proton transfer following irradiation of the hydrogen-bonded single water complex of 7-azaindole with UV light.  

PubMed

High resolution electronic spectra of the single water complex of 7-azaindole (7AIW) and of a deuterated analog (7AIW-d(3)) have been recorded in a molecular beam, both in the absence and presence of an applied electric field. The obtained data include the rotational constants of both complexes in their ground (S(0)) and first excited (S(1)) electronic states, their S(1)-S(0) electronic transition moment and axis-tilting angles, and their permanent electric dipole moments (EDM's) in both electronic states. Analyses of these data show that the water molecule forms two hydrogen bonds with 7AI, a donor O-H···N(7) bond and an acceptor O···H-N(1) bond. The resulting structure has a small EDM in the S(0) state (? = 0.54 D) but a greatly enhanced EDM in the S(1) state (? = 3.97 D). We deduce from the EDM's of the component parts that 0.281 e(-) of charge is transferred from the acidic N(1)-H site to the basic N(7) site upon UV excitation of 7AIW, but that water-assisted proton transfer from N(1) to N(7) does not occur. A model of the resulting electrostatic interactions in the solute-solvent pair predicts a solvent-induced red-shift of 1260 cm(-1) which compares favorably to the experimental value of 1290 cm(-1). PMID:21895179

Young, Justin W; Pratt, David W

2011-08-28

227

Excited state electron transfer precedes proton transfer following irradiation of the hydrogen-bonded single water complex of 7-azaindole with UV light  

NASA Astrophysics Data System (ADS)

High resolution electronic spectra of the single water complex of 7-azaindole (7AIW) and of a deuterated analog (7AIW-d3) have been recorded in a molecular beam, both in the absence and presence of an applied electric field. The obtained data include the rotational constants of both complexes in their ground (S0) and first excited (S1) electronic states, their S1- S0 electronic transition moment and axis-tilting angles, and their permanent electric dipole moments (EDM's) in both electronic states. Analyses of these data show that the water molecule forms two hydrogen bonds with 7AI, a donor O-H...N7 bond and an acceptor O...H-N1 bond. The resulting structure has a small EDM in the S0 state (? = 0.54 D) but a greatly enhanced EDM in the S1 state (? = 3.97 D). We deduce from the EDM's of the component parts that 0.281 e- of charge is transferred from the acidic N1-H site to the basic N7 site upon UV excitation of 7AIW, but that water-assisted proton transfer from N1 to N7 does not occur. A model of the resulting electrostatic interactions in the solute-solvent pair predicts a solvent-induced red-shift of 1260 cm-1 which compares favorably to the experimental value of 1290 cm-1.

Young, Justin W.; Pratt, David W.

2011-08-01

228

A minichannel aluminium tube heat exchanger – Part I: Evaluation of single-phase heat transfer coefficients by the Wilson plot method  

Microsoft Academic Search

A prototype liquid-to-refrigerant heat exchanger was developed with the aim of minimizing the refrigerant charge in small systems. To allow correct calculation of the refrigerant side heat transfer, the heat exchanger was first tested for liquid-to-liquid (water-to-water) operation in order to determine the single-phase heat transfer performance. These single-phase tests are reported in this paper. The heat exchanger was made

Primal Fernando; Björn Palm; Tim Ameel; Per Lundqvist; Eric Granryd

2008-01-01

229

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

E-print Network

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

Nair, Nitish

2009-01-01

230

Single-phase heat transfer improved by helical inserts in tubes  

NASA Technical Reports Server (NTRS)

Helical-vane insert creates a single, well defined helical flow passage resulting in more reliable predictions and extrapolations of the thermal and hydraulic performance. Insert core houses instrumentation which does not disturb the flow.

Gutsein, M. U.

1970-01-01

231

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

PubMed Central

Objective Obese women experience worse reproductive outcomes compared to normal weight women, specifically infertility, pregnancy loss, fetal malformations and developmental delay. The objective of this study was to use a genetic mouse model of obesity in order to recapitulate the human reproductive phenotype and further examine potential mechanisms and therapies. Methods New inbred, polygenic Type 2 diabetic TallyHO mice and age matched control C57BL/6 mice were superovulated to obtain morulae or blastocysts stage embryos which were cultured in human tubal fluid media. Deoxyglucose uptake was performed on insulin-stimulated individual blastocysts. Apoptosis was detected by confocal microscopy using TUNEL assay and Topro-3 nuclear dye. Embryos were scored for %TUNEL positive/total nuclei. AMPK activation, TNF? expression, and adiponectin expression were analyzed by western immunoblot and confocal immunofluorescent microscopy. Lipid accumulation was assayed by Bodipy. Finally all measured parameters were compared between TallyHO mice in morulaes cultured to blastocyst embryos in either human tubal fluid (HTF) media or HTF with 25ug/ml metformin added. Results TallyHo mice developed whole body abnormal insulin tolerance, decreased litter number and increased NEFA. Blastocysts demonstrated increased apoptosis, decreased insulin sensitivity, and decreased activation of AMP activated protein-kinase (AMPK). As a possible cause of the insulin resistance/abnormal P-AMPK, we found that Tumor necrosis Factor (TNF?) expression and lipid accumulation as detected by BODIPY were increased in TallyHO blastocysts and adiponectin was decreased. Culturing TallyHO morulae with the AMPK activator, metformin lead to a reversal of all abnormal findings, including increased p-AMPK, improved insulin-stimulated glucose uptake and normalization of lipid accumulation. Conclusions Women with obesity and insulin resistance experience poor pregnancy outcomes. Previously we have shown in mouse models of insulin resistance that AMPK activity is decreased and that activators of AMPK reverse the poor embryo outcomes. Here, we show for the first time using a genetically altered obese model, not a diet-induced model, that metformin reverses many of the adverse effects of obesity at the level of the blastocyst. Expanding on this we determine that activation of AMPK via metformin reduces lipid droplet accumulation, presumably by eliminating the inhibitory effects of TNF?, resulting in normalization of fatty acid oxidation and HADH2 activity. Metformin exposure in vitro was able to partially reversing these effects, at the level of the blastocyst and thus may be effective in preventing the adverse effects of obesity on pregnancy and reproductive outcomes. PMID:25472042

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

2015-01-01

232

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

PubMed

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

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

2015-02-27

233

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

234

Blocking single-stranded transferred DNA conversion to double-stranded intermediates by overexpression of yeast DNA REPLICATION FACTOR A.  

PubMed

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

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

2015-01-01

235

Oct4 cell-autonomously promotes primitive endoderm development in the mouse blastocyst  

PubMed Central

Summary 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 are required for 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 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

2014-01-01

236

Biodynamic imaging of live porcine oocytes, zygotes and blastocysts for viability assessment in assisted reproductive technologies  

PubMed Central

The success of assisted reproductive technologies relies on accurate assessment of reproductive viability at successive stages of development for oocytes and embryos. The current scoring system used to select good-quality oocytes relies on morphologically observable traits and hence is indirect and subjective. Biodynamic imaging may provide an objective approach to oocyte and embryo assessment by measuring physiologically-relevant dynamics. Biodynamic imaging is a coherence-gated approach to 3D tissue imaging that uses digital holography to perform low-coherence speckle interferometry to capture dynamic light scattering from intracellular motions. The changes in intracellular activity during cumulus oocyte complex maturation, before and after in vitro fertilization, and the subsequent development of the zygote and blastocyst provide a new approach to the assessment of preimplant candidates.

An, Ran; Wang, Chunmin; Turek, John; Machaty, Zoltan; Nolte, David D.

2015-01-01

237

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

PubMed Central

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

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

2014-01-01

238

Automated Hydrogen/Deuterium Exchange Electron Transfer Dissociation High Resolution Mass Spectrometry Measured at Single-Amide Resolution  

NASA Astrophysics Data System (ADS)

Hydrogen deuterium exchange mass spectrometry (HDX-MS) is a well established method for the measurement of solution-phase deuterium incorporation into proteins, which can provide insight into protein conformational mobility. However, most HDX measurements are constrained to regions of the protein where pepsin proteolysis allows detection at peptide resolution. Recently, single-amide resolution deuterium incorporation has been achieved by limiting gas-phase scrambling in the mass spectrometer. This was accomplished by employing a combination of soft ionization and desolvation conditions coupled with the radical-driven fragmentation technique electron transfer dissociation (ETD). Here, a hybrid LTQ-Orbitrap XL is systematically evaluated for its utility in providing single-amide deuterium incorporation for differential HDX analysis of a nuclear receptor upon binding small molecule ligands. We are able to show that instrumental parameters can be optimized to minimize scrambling and can be incorporated into an established and fully automated HDX platform making differential single-amide HDX possible for bottom-up analysis of complex systems. We have applied this system to determine differential single amide resolution HDX data for the peroxizome proliferator activated receptor bound with two ligands of interest.

Landgraf, Rachelle R.; Chalmers, Michael J.; Griffin, Patrick R.

2012-02-01

239

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

SciTech Connect

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

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

1993-09-08

240

Comparison of Different Correlating Methods for the Single-Phase Heat Transfer Data in Laminar and Turbulent Flow Regions  

NASA Astrophysics Data System (ADS)

The experimental heat transfer results, typically expressed as Nusselt number, are usually put in the form of an empirical correlation. Different correlating methods can be used to establish the correlation, such as the traditional least-squares method, artificial neural networks (ANN), and symbolic regression, to name a few. In this study, ANN and symbolic regression will be compared with the traditional least-squares method. Correlations using ANN and symbolic regression were developed first and through contribution analysis we were able to evaluate which correlating method can directly extract more physical meaning. Correlations were developed based on the single-phase heat transfer data [1]. The accuracy of these new correlations is comparable to the traditional least-squares correlations. From the contribution analysis, the importance of each independent variable in the ANN correlations can be examined by the index of contribution [2]. For symbolic correlation, the insignificant variable can be eliminated from the correlation. Therefore, both methods in addition to providing accurate predictions of the heat transfer data also provide correct physical insight as to the contribution of the input variables.

Tam, H. K.; Tam, L. M.; Ghajar, A. J.; Lei, C. U.

2010-05-01

241

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

SciTech Connect

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

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

2005-09-01

242

Debating Elective Single Embryo Transfer after in vitro Fertilization: A Plea for a Context-Sensitive Approach  

PubMed Central

The number of embryos transferred after in vitro fertilization (IVF) have been a topic of debate for over a decade now. Due to the risk associated with multiple pregnancy, there has been a global effort at reducing the multiple pregnancy rates to a minimum while maintaining an acceptable level of successful IVF pregnancy rate. Elective single embryo transfer (eSET) is advocated in most European countries. In Belgium and Sweden, eSET is mandatory for couples with a good prognosis. However, despite clinical recommendations and policy statements, patients in clinical practice frequently do request for the transfer of multiple embryos in order to have twins. Such requests conflict with policy guidelines and create an ethical dilemma for physicians: Should the physician do as the couple requests, and there with respect the autonomy of patients, or adhere to medical policy that takes the health of the mother and children at heart? This article provides an exploration of the arguments found in the literature that plays a role in the discussion on this topic and eventually argues that what a physician should do depends on the specificities of the context in which patients and physicians are implicated. These contextual issues can be taken into account in a shared decision-making procedure, which allows reflections and the responsibilities of both patients and physicians to be attended in decision about assisted reproduction.

Ezugwu, EC; der Burg, S Van

2015-01-01

243

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

244

Study of sequential dexter energy transfer in high efficient phosphorescent white organic light-emitting diodes with single emissive layer.  

PubMed

In this study, we report our effort to realize high performance single emissive layer three color white phosphorescent organic light emitting diodes (PHOLEDs) through sequential Dexter energy transfer of blue, green and red dopants. The PHOLEDs had a structure of; ITO(1500 Å)/NPB(700 Å)/mCP:Firpic-x%:Ir(ppy)3-0.5%:Ir(piq)3-y%(300 Å)/TPBi(300 Å)/Liq(20 Å)/Al(1200 Å). The dopant concentrations of FIrpic, Ir(ppy)3 and Ir(piq)3 were adjusted and optimized to facilitate the preferred energy transfer processes attaining both the best luminous efficiency and CIE color coordinates. The presence of a deep trapping center for charge carriers in the emissive layer was confirmed by the observed red shift in electroluminescent spectra. White PHOLEDs, with phosphorescent dopant concentrations of FIrpic-8.0%:Ir(ppy)3-0.5%:Ir(piq)3-0.5% in the mCP host of the single emissive layer, had a maximum luminescence of 37,810 cd/m(2) at 11 V and a luminous efficiency of 48.10 cd/A at 5 V with CIE color coordinates of (0.35, 0.41). PMID:25388087

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

2014-01-01

245

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

246

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

SciTech Connect

Neutron transfer reactions were performed in inverse kinematics using radioactive ion beams of {sup 132}Sn, {sup 130}Sn, and {sup 134}Te and deuterated polyethylene targets. Preliminary results are presented. The Q-value spectra for {sup 133}Sn, {sup 131}Sn and {sup 135}Te reveal a number of previously unobserved peaks. The angular distributions are compatible with the expected lf{sub 7/2} nature of the ground state of {sup 133}Sn, and 2p{sub 3/2} for the 3.4 MeV state in {sup 131}Sn.

Jones, K. J. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ 08903 (United States); Pain, S. D. [Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ 08903 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kozub, R. L.; Howard, J. A.; O'Malley, P. D.; Paulauskas, S. V.; Shriner, J. F.; Sissom, D. J. [Department of Physics, Tennessee Technological University, Cookeville, TN 38505 (United States); Adekola, A. S. [Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Bardayan, D. W.; Blackmon, J. C.; Liang, J. F.; Nesaraja, C. D.; Shapira, D.; Smith, M. S. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Catford, W. N.; Harlin, C.; Patterson, N. P.; Swan, T. P.; Wilson, G. L. [Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)] (and others)

2009-03-04

247

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

248

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

SciTech Connect

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

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

2009-01-01

249

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

250

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

251

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

252

Protocols for nuclear transfer in mice.  

PubMed

Cloning by nuclear transfer in mammals has revealed the remarkable ability of an oocyte to reprogram transferred cell nuclei and induce them to recapitulate the developmental program. This chapter summarizes the method used since 1998 for mouse cloning, which differs from that for large animal cloning. A Piezo-drill micromanipulator allows direct injection of nuclei into enucleated mice oocytes instead of the electrofusion method used for introducing a nucleus into an enucleated oocyte of a large animal. After activation, reconstructed embryos are allowed to develop to the morulae or blastocyst stage before transfer into surrogate mothers. PMID:16761716

Gao, Shaorong

2006-01-01

253

Impact of transient single-phase heat transfer modeling on predicted BWR fuel stability margins  

Microsoft Academic Search

Boiling flow instabilities must be considered in the design and analysis of many devices in energy production, e.g., boiling water nuclear reactors (BWRs). The most common thermal-hydraulic instability mechanism of interest to BWR operation in known as density-wave oscillations. An important aspect of analytically investigating density-wave oscillations deals with heater wall dynamic modeling in the single- and two-phase regions, respectively.

R. P. Taleyarkhan; A. F. McFarlane; M. Z. Podowski; R. T. Jr. Lahey

1987-01-01

254

Projectile angular-differential cross sections for single electron transfer in fast He+–He collisions  

NASA Astrophysics Data System (ADS)

The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singly positive charged helium ions with helium atoms in their ground states. The formalism satisfies the correct boundary conditions. The influence of the dynamic electron correlations on the cross sections is studied by considering the inter electronic interactions in the complete perturbation potentials in post form. Also, the sensitivity of the cross sections to the static electronic correlations is studied by using the single-zeta and the highly correlated Byron–Joachain wave functions to describe the initial bound state of the active electrons. The obtained results for the energy range of 40–5000 keV/amu are reported and compared with other three- and four-body theoretical data and available experimental measurements. The comparison leads us to discuss the validity of the applied approach and survey the interaction effects on the cross sections by recognizing the electron–electron interaction. Particularly, for differential cross sections, the comparison of the present four-body method with the experiment shows that the agreement is not as good as that for its three-body version.

Ebrahim, Ghanbari-Adivi; Hoda, Ghavaminia

2015-03-01

255

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

256

Effect of the Pr3+ ? Gd3+ energy transfer in multicomponent garnet single crystal scintillators  

NASA Astrophysics Data System (ADS)

Luminescence processes in the undoped and Pr3+-doped (Gd,RE)3(Ga,Al)5O12, RE = Lu,Y, multicomponent garnets are studied by time-resolved photoluminescence spectroscopy. Energy transfer processes between Pr3+ and Gd3+ causing significant deterioration of the scintillation performance are considered in detail. As is shown in current work, an overlap of the 5d1-3H4 emission transition of Pr3+ and 8S-6Px absorption transition of Gd3+ results in unwanted depletion of Pr3+ 5d1 excited state and is further intensified by the concentration quenching in the Gd3+-sublattice. This process explains a drastic decrease of light yield in Pr3+-doped Gd3+-containing multicomponent garnets observed in a previous work.

Babin, V.; Nikl, M.; Kamada, K.; Beitlerova, A.; Yoshikawa, A.

2013-09-01

257

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] [ORNL; Onar, Omer C [ORNL] [ORNL; Miller, John M [ORNL] [ORNL; Tang, Lixin [ORNL] [ORNL

2013-01-01

258

Device study, chemical doping, and logic circuits based on transferred aligned single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this paper, high-performance back-gated carbon nanotube field-effect transistors based on transferred aligned carbon nanotubes were fabricated and studies found that the on/off ratio can reach 107 and the current density can reach 1.6?A/?m after electrical breakdown. In addition, chemical doping with hydrazine was used to convert the p-type aligned nanotube devices into n-type. These devices were further utilized to demonstrate various logic circuits, including p-type metal-oxide-semiconductor inverters, diode-loaded inverters, complementary metal-oxide-semiconductor inverters, NAND, and NOR gates. This approach could work as the platform for future nanotube-based nanoelectronics.

Wang, Chuan; Ryu, Koungmin; Badmaev, Alexander; Patil, Nishant; Lin, Albert; Mitra, Subhasish; Wong, H.-S. Philip; Zhou, Chongwu

2008-07-01

259

Probing Single-Molecule T4 Lysozyme Conformational Dynamics by Intramolecular Fluorescence Energy Transfer  

SciTech Connect

We demonstrate the use of single-molecule spectroscopy to study enzyme conformational motions of T4 lysozyme under hydrolysis reaction of the polysaccharide walls of E. Coli B cells.By attaching a donoracceptor pair of dye molecules site-specifically to noninterfering sites on the enzyme, the hinge-bending motions of the enzyme are measured by monitoring the donor-acceptor emission intensity as a function of time. The overall enzymatic reaction rate constants are found to vary widely from molecule to molecule. The dominant contribution to this static inhomogeneity is attributed to enzyme searching for reactive sites on the substrate.

Chen, Yu; Hu, Dehong; Vorpagel, Erich R.; Lu, H PETER.

2003-07-16

260

Calculations of [ital Q] values in single- and double-charge-transfer collisions of highly charged ions with atoms  

SciTech Connect

Close-coupling calculations are carried out for the [ital Q] values for electron capture processes in collisions of multiply charged ions with atoms over a broad range of energies. For single-capture processes the results for N[sup 7+]+He and O[sup 8+]+He collisions are in good agreement with the experimental data of Wu [ital et] [ital al]. [preceding paper, Phys. Rev. A 50, 502 (1994)]. To compare with the experimental [ital Q] values for the transfer ionization (TI) and the true double-capture (TDC) processes, an independent-electron model was used to calculate double-electron-capture cross sections. By combining with the calculated average fluorescence yields, the theoretical [ital Q] values for TI and TDC processes are also found to be in fair agreement with the experimental data. We also compared the [ital Q] values calculated by the close-coupling method and by the classical-trajectory Monte Carlo method.

Chen, Z.; Lin, C.D. (Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)); Toshima, N. (Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305 (Japan))

1994-07-01

261

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

SciTech Connect

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

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

2014-01-01

262

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

PubMed

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

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

2014-10-01

263

Single-electron Born approximations for charge transfer from multielectron atoms to protons  

NASA Technical Reports Server (NTRS)

The Born approximation, including the internuclear interaction, is used to compute cross sections for the transfer of one electron from a multielectron atom to an incident proton. When the full internuclear interaction is included, the results lie far above high-energy experimental K-shell data for protons and argon. However, when only enough internuclear interaction is included so that the total projectile-target interaction goes to zero asymptotically in accordance with plane-wave functions actually used, fair agreement at high energies is obtained. The latter form of the Born approximation is compared with data on K-shell capture from helium as well as argon and with the simpler approximation of Oppenheimer and of Brinkman and Kramers (OBK), where no internuclear interaction is included. The OBK results typically lie a factor of 2 to 8 above the data, while the present Born results are within a factor of 2 of most of the existing high-velocity K-shell data.

Omidvar, K.; Golden, J. E.; Mcguire, J. H.; Weaver, L.

1976-01-01

264

Cellobiose dehydrogenase aryl diazonium modified single walled carbon nanotubes: enhanced direct electron transfer through a positively charged surface.  

PubMed

One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 ?A cm(-2) at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

Tasca, Federico; Harreither, Wolfgang; Ludwig, Roland; Gooding, John Justin; Gorton, Lo

2011-04-15

265

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

PubMed

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

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

2007-06-01

266

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

267

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

PubMed Central

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

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

2014-01-01

268

Extreme bendability of single-walled carbon nanotube networks transferred from high-temperature growth substrates to plastic and their use in thin-film transistors  

Microsoft Academic Search

In this paper we describe printing methods for transferring single-walled carbon nanotubes (SWNTs) from high-temperature growth substrates to flexible, low-cost plastic supports. Thin-film transistors (TFTs) built with networks of transferred SWNTs grown by chemical vapor deposition show good performance-mobilities and on\\/off current ratios similar to those of devices fabricated on the growth substrates for a wide range of channel lengths.

Seung-Hyun Hur; John. A. Rogers

2005-01-01

269

Cross sections of charge transfer between a Gd atom and its singly charged positive ion in metastable states close to the ground state  

Microsoft Academic Search

The charge-transfer cross sections between a gadolinium atom and its singly charged positive ion in metastable states have been measured with a crossed-beam apparatus. The primary ions are produced by photo- ionization with a tunable dye laser. The populations of primary ions in excited states have been measured by the laser-induced fluorescence method. By measuring the populations, the charge-transfer cross

M. Hashida; S. Sakabe; Y. Izawa

1996-01-01

270

Generation of single-stranded T-DNA molecules during the initial stages of T-DNA transfer from Agrobacterium tumefaciens to plant cells  

Microsoft Academic Search

Activation of the T-DNA transfer process of Agrobacterium by the plant signal molecule acetosyringone generates a single-stranded, unipolar, linear T-DNA molecule (T-strand)-a potential conjugative intermediate in the transfer of the T-DNA to plant cells. Acetosyringone induction also leads to S1 nuclease-sensitive sites at the Ti plasmid T-DNA borders, and other molecular changes associated with the Ti plasmid T-DNA sequences, which

Scott E. Stachel; Benedikt Timmerman; Patricia Zambryski

1986-01-01

271

Production and Lambing Rate of Blastocysts Derived from In Vitro Matured Oocytes After Gonadotropin Treatment of Prepubertal Ewes1  

Microsoft Academic Search

The aim of this study was to evaluate the effect of gonadotropin treatment on the in vitro maturation, blastocyst production, and developmental potential to term of oocytes collected from Sardinian neonatal and prepubertal ewes at 4 to 6 wk of age. Cumulus-oocyte complexes were recovered at 24 h after withdrawal of a 1\\/6th size progestagenated pessary from the donors, of

S. Ledda; L. Bogliolo; G. Leoni; S. Naitana

272

Both the folate cycle and betaine-homocysteine methyltransferase contribute methyl groups for DNA methylation in mouse blastocysts.  

PubMed

The embryonic pattern of global DNA methylation is first established in the inner cell mass (ICM) of the mouse blastocyst. The methyl donor S-adenosylmethionine (SAM) is produced in most cells through the folate cycle, but only a few cell types generate SAM from betaine (N,N,N-trimethylglycine) via betaine-homocysteine methyltransferase (BHMT), which is expressed in the mouse ICM. Here, mean ICM cell numbers decreased from 18-19 in controls to 11-13 when the folate cycle was inhibited by the antifolate methotrexate and to 12-14 when BHMT expression was knocked down by antisense morpholinos. Inhibiting both pathways, however, much more severely affected ICM development (7-8 cells). Total SAM levels in mouse blastocysts decreased significantly only when both pathways were inhibited (from 3.1 to 1.6 pmol/100 blastocysts). DNA methylation, detected as 5-methylcytosine (5-MeC) immunofluorescence in isolated ICMs, was minimally affected by inhibition of either pathway alone but decreased by at least 45-55% when both BHMT and the folate cycle were inhibited simultaneously. Effects on cell numbers and 5-MeC levels in the ICM were completely rescued by methionine (immediate SAM precursor) or SAM. Both the folate cycle and betaine/BHMT appear to contribute to a methyl pool required for normal ICM development and establishing initial embryonic DNA methylation.-Zhang, B., Denomme, M.M., White, C. R., Leung, K.-Y., Lee, M. B., Greene, N. D. E., Mann, M. R. W., Trasler, J. M., Baltz, J. M. Both the folate cycle and betaine-homocysteine methyltransferase contribute methyl groups for DNA methylation in mouse blastocysts. PMID:25466894

Zhang, Baohua; Denomme, Michelle M; White, Carlee R; Leung, Kit-Yi; Lee, Martin B; Greene, Nicholas D E; Mann, Mellissa R W; Trasler, Jacquetta M; Baltz, Jay M

2015-03-01

273

Injection of Wild Type Embryonic Stem Cells into Mst1 Transgenic Blastocysts Prevents Adult-Onset Cardiomyopathy  

PubMed Central

Embryonic stem cells have the capacity to differentiate into a wide range of cell types. We previously described that blastocyst injection of wild type (WT) embryonic stem cells (ESCs) into various knockout (KO) mouse models of human disease prevents disease from occurring. In this study we ask if the blastocyst approach can also correct defects in a mouse model of transgenic (Tg) overexpression of a pro-apoptotic factor. We injected ROSA26 (LacZ-marked) WT ESCs into human mammalian sterile 20 like-kinase 1 (Mst1) Tg blastocysts. Mst1 Tg mice overexpress Mst1, a pro-apoptotic factor, in a cardiac-specific manner. As a result, Mst1 Tg mice develop adult dilated cardiomyopathy driven by apoptosis, reduction in cell density and no hypertrophic compensation. Incorporation of WT ESCs generated WT/Mst1 chimeric mice with normal hearts at histological and functional levels. Accordingly, apoptosis and cell density parameters were normalized. The experiments suggest that an adult-onset cardiac myopathy induced by overexpression of the pro-apoptotic Mst1 can be reversed by developmental incorporation of WT ESCs. The findings also suggest that since forced expression of the Mst1 transgene is not abolished in the rescued chimeras, the WT ES-derived cells normalize pathways that lie downstream of Mst1. The results expand the therapeutic capability of the ESCs to mouse models that overproduce detrimental proteins. PMID:21086068

Zhao, Qingshi; Beck, Amanda J.; Vitale, Joseph M.; Schneider, Joel S.; Chang, Corey; Gao, Shumin; del Re, Dominic; Bhaumik, Mantu; Yehia, Ghassan; Sadoshima, Junichi

2011-01-01

274

Tight junction protein ZO-2 expression and relative function of ZO-1 and ZO-2 during mouse blastocyst formation  

SciTech Connect

Apicolateral tight junctions (TJs) between epithelial cells are multiprotein complexes regulating membrane polarity and paracellular transport and also contribute to signalling pathways affecting cell proliferation and gene expression. ZO-2 and other ZO family members form a sub-membranous scaffold for binding TJ constituents. We investigated ZO-2 contribution to TJ biogenesis and function during trophectoderm epithelium differentiation in mouse preimplantation embryos. Our data indicate that ZO-2 is expressed from maternal and embryonic genomes with maternal ZO-2 protein associated with nuclei in zygotes and particularly early cleavage stages. Embryonic ZO-2 assembled at outer blastomere apicolateral junctional sites from the late 16-cell stage. Junctional ZO-2 first co-localised with E-cadherin in a transient complex comprising adherens junction and TJ constituents before segregating to TJs after their separation from the blastocyst stage (32-cell onwards). ZO-2 siRNA microinjection into zygotes or 2-cell embryos resulted in specific knockdown of ZO-2 mRNA and protein within blastocysts. Embryos lacking ZO-2 protein at trophectoderm TJs exhibited delayed blastocoel cavity formation but underwent normal cell proliferation and outgrowth morphogenesis. Quantitative analysis of trophectoderm TJs in ZO-2-deficient embryos revealed increased assembly of ZO-1 but not occludin, indicating ZO protein redundancy as a compensatory mechanism contributing to the mild phenotype observed. In contrast, ZO-1 knockdown, or combined ZO-1 and ZO-2 knockdown, generated a more severe inhibition of blastocoel formation indicating distinct roles for ZO proteins in blastocyst morphogenesis.

Sheth, Bhavwanti; Nowak, Rachael L.; Anderson, Rebecca; Kwong, Wing Yee; Papenbrock, Thomas [School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX (United Kingdom); Fleming, Tom P. [School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX (United Kingdom)], E-mail: tpf@soton.ac.uk

2008-11-01

275

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

PubMed Central

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

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

2014-01-01

276

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

PubMed

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

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

2015-02-15

277

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

PubMed Central

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

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

2015-01-01

278

Differential but beneficial effect of phytohemagglutinin on efficiency of in vitro porcine embryo production by somatic cell nuclear transfer or in vitro fertilization.  

PubMed

In vitro production of porcine embryos has become routine in most laboratories but the yield and quality of the resultant blastocysts remains sub-optimal. Phytohemagglutinin (PHA) is an N-acetylgalactosamine/galactose sugar-specific lectin with a wide variety of biological activities including mitogenesis, mediation of cell recognition and agglutination of cells. This study was therefore, designed to investigate the effect of PHA on the preimplantation development and quality of parthenogenetic, somatic cell nuclear transferred (SCNT) and in vitro fertilized (IVF) porcine embryos cultured in the absence or presence of PHA. Analysis showed that, supplementation of PHA significantly improved the blastocyst rate of parthenogenetic (70.6 +/- 0.2 vs. 51.4 +/- 0.6%) and SCNT (27.7 +/- 1.7 vs. 12.5 +/- 0.3%) embryos but not IVF embryos (25.0 +/- 14.3 vs. 20.1 +/- 12.7%). Nonetheless, PHA-treated blastocysts had higher hatching ability and contained higher cell number than control blastocysts in all the groups (P < 0.05). TUNEL labeling revealed that blastocysts cultured in the presence of PHA were less predisposed to biochemical apoptosis and showed lower indices of TUNEL, fragmentation and total apoptosis than those cultured in the absence of PHA (P < 0.05). Real time qRT-PCR analysis of parthenogenetic blastocysts revealed that PHA decreased the expression ratio of BAX:BCL-xL transcripts. Therefore, our study suggests that PHA improves the blastocyst yield and quality by enhancing blastocyst expansion, hatching and total cell number and decreasing the apoptosis. However, PHA has a differential effect on development rate of IVF derived embryos. These results may represent an approach towards achieving better preimplantation development of porcine embryos in vitro. PMID:17474088

Gupta, Mukesh Kumar; Uhm, Sang Jun; Lee, Hoon Taek

2007-12-01

279

Generation of completely embryonic stem cell-derived mutant mice using tetraploid blastocyst injection.  

PubMed

Embryonic stem (ES) cells provide a unique tool for producing specifically designed mutations in mice. Here, we describe an alternative approach toward the generation of mice which are derived completely from ES cells (ES mice), as judged by glucose phosphate isomerase (GPI) analysis, without prior passage through the germline. By injecting wild-type and mutant ES cells into tetraploid blastocysts, viable and fertile ES mice were generated, suggesting that totipotency of ES cells was not affected by long-term culture and experimental manipulation in vitro. When ES cell clones harboring a lacZ reporter gene introduced by either targeted insertion or a gene-trap approach were used, the expression pattern of the lacZ gene in ES fetuses was identical to that of fetuses that were derived from breeding of chimeric mice. Thus, this technique can be considered as a useful and rapid approach to produce fetuses and mice directly from ES cells carrying predetermined genetic changes and offers many applications for studies in molecular genetics and developmental biology. PMID:9152006

Wang, Z Q; Kiefer, F; Urbánek, P; Wagner, E F

1997-03-01

280

Recombination activation gene-2-deficient blastocyst complementation analysis reveals an essential role for nuclear factor I-A transcription factor in T-cell activation  

PubMed Central

Nuclear factor I (NFI)-A is a member of the NFI family of transcription factors implicated in regulation of granulocyte differentiation. However, its role in the lymphoid lineage is not known. NFI-A deficiency results in perinatal lethality, thus precluding analysis of the role of NFI-A in lymphocyte development and function. Using recombination activation gene-2-deficient (RAG-2?/?) blastocysts and embryonic stem cells with homozygous NFI-A gene deletion, we show an essential role for NFI-A in T-cell activation. NFI-A?/??RAG-2?/? chimeric mice had normal distributions of CD4?CD8? double negative, CD4+CD8+ double positive, CD4+CD8? and CD4?CD8+-single positive cells in the thymus and CD4+CD8? and CD4?CD8+ cells in spleen and lymph nodes. However, NFI-A?/??RAG-2?/? mice had severely reduced thymus size and hypocellularity. The decrease in thymocytes and peripheral T cells in NFI-A?/??RAG-2?/? chimeric mice is attributed to proliferative defects associated with decreased blast transformation, CD69 expression and DNA synthesis in response to T antigen receptor stimulation. Interestingly, NFI-A-null T cells showed increased levels of c-myc transcription that is inhibited in response to antigen receptor-mediated activation. These studies demonstrate for the first time a requirement for the NFI-A transcription factor in antigen receptor-induced T-cell activation events. PMID:21602176

Chen, Hui-Chen; Rajgolikar, Girish; Butz, Kenneth G.; Frissora, Frank W.; Gronostajski, Richard M.

2011-01-01

281

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. PMID:7533171

1995-01-01

282

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

NASA Astrophysics Data System (ADS)

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

Filatov, Michael

2014-09-01

283

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

284

Cholesterol-induced lipophobic interaction between transmembrane helices using ensemble and single-molecule fluorescence resonance energy transfer.  

PubMed

The solvent environment regulates the conformational dynamics and functions of solvated proteins. In cell membranes, cholesterol, a major eukaryotic lipid, can markedly modulate protein dynamics. To investigate the nonspecific effects of cholesterol on the dynamics and stability of helical membrane proteins, we monitored association-dissociation dynamics on the antiparallel dimer formation of two simple transmembrane helices (AALALAA)3 with single-molecule fluorescence resonance energy transfer (FRET) using Cy3B- and Cy5-labeled helices in lipid vesicles (time resolution of 17 ms). The incorporation of 30 mol % cholesterol into phosphatidylcholine bilayers significantly stabilized the helix dimer with average lifetimes of 450-170 ms in 20-35 °C. Ensemble FRET measurements performed at 15-55 °C confirmed the cholesterol-induced stabilization of the dimer (at 25 °C, ??G(a) = -9 kJ mol(-1) and ??Ha = -60 kJ mol(-1)), most of which originated from "lipophobic" interactions by reducing helix-lipid contacts and the lateral pressure in the hydrocarbon core region. The temperature dependence of the dissociation process (activation energy of 48 kJ) was explained by the Kramers-type frictional barrier in membranes without assuming an enthalpically unfavorable transition state. In addition to these observations, cholesterol-induced tilting of the helices, a positive ?C(p(a)), and slower dimer formation compared with the random collision rate were consistent with a hypothetical model in which cholesterol stabilizes the helix dimer into an hourglass shape to relieve the lateral pressure. Thus, the liposomal single-molecule approach highlighted the significance of the cholesterol-induced basal force for interhelical interactions, which will aid discussions of complex protein-membrane systems. PMID:25629582

Yano, Yoshiaki; Kondo, Kotaro; Kitani, Ryota; Yamamoto, Arisa; Matsuzaki, Katsumi

2015-02-17

285

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

PubMed

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. PMID:11087856

Talaga, D S; Lau, W L; Roder, H; Tang, J; Jia, Y; DeGrado, W F; Hochstrasser, R M

2000-11-21

286

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

NASA Astrophysics Data System (ADS)

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 ?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 SiO2 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

2007-05-01

287

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

2013-04-01

288

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

SciTech Connect

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

Xu, Jie; Xu, Jun, E-mail: junxu@nju.edu.cn; Lu, Peng; Shan, Dan; Li, Wei; Chen, Kunji [National Laboratory of Solid State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

2014-10-07

289

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

290

Nonspherical Nanoparticles with Controlled Morphologies via Seeded Surface-Initiated Single Electron Transfer Radical Polymerization in Soap-Free Emulsion.  

PubMed

This work reports a facile novel approach to prepare asymmetric poly(vinylidene fluoride)/polystyrene (PVDF/PS) composite latex particles with controllable morphologies using one-step soap-free seeded emulsion polymerization, i.e., surface-initiated single electron transfer radical polymerization (SET-RP) of styrene (St) at the surface of PVDF seed particles. It was observed that the morphology was influenced mainly by the St/PVDF feed ratio, the polymerization temperature, and the length of the catalyst Cu(0) wire (? 1.00 mm). When the feed ratio was St/PVDF = 5.0 g/1.0 g, snowman-like Janus particles were exclusively obtained. Raspberry-like and popcorn-like composite particles were observed at a higher reaction temperature or a shorter length of the catalyst wire. The reaction kinetics plots demonstrated some unique features. The formation of nonspherical composite nanoparticles can be ascribed to the surface nucleation of PS bulges following the SET-RP. PMID:25797695

Yuan, Jinfeng; Wang, Lixia; Zhu, Lei; Pan, Mingwang; Wang, Wenjie; Liu, Ying; Liu, Gang

2015-04-14

291

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

PubMed Central

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

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

2014-01-01

292

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

NASA Astrophysics Data System (ADS)

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-?m 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.

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

2002-03-01

293

Effect of cumulus cell coculture and oxygen tension on the in vitro developmental competence of bovine zygotes cultured singly.  

PubMed

The customary practice in bovine in vitro embryo production (IVP) is to handle oocytes and embryos in groups; although there are several reasons for establishing an IVP system for individual embryos that allows for following a single oocyte from retrieval through development to the blastocyst stage. To date, reports of individual IVP are inconsistent, and in most cases, resulted in unsatisfactory blastocyst rates. The objective of this study was to develop an efficient system for routine in vitro culture of individual bovine embryos. Single culture of zygotes in 2 different culture volumes (20 and 500microL) yielded less than 3% blastocysts in experiment 1. In an attempt to improve these results, cumulus cells were added to the culture medium in experiment 2, after which blastocyst rates increased from 2.9 to 21.8% (P<0.05). The third experiment revealed that an atmospheric oxygen tension, which is commonly used with somatic cell coculture, was not beneficial during individual embryo-cumulus cell coculture, because it resulted in lower blastocyst rates (Odds ratio 0.57, P<0.001) and in lower blastocyst cell numbers (P<0.05), when compared to culture in 5% oxygen. Grouped vs. single culture and reduced oxygen tension did not have a significant effect on cleavage and hatching rates. In experiment 4, three different cumulus cell coculture conditions during individual culture were tested and compared with the cleavage, blastocyst and hatching rates, and cell number of group culture (73.2%, 36.4%, 66.7% and, 155.1+/-7.26, respectively). The outcome variables after individual embryo culture on a 5-day-old cumulus cell monolayer (74.1%, 38.2%, 71.9% and 133.4+/-9.16, respectively), and single culture in the presence of added cumulus cells (69.9%, 31.9%, 66.7% and 137.3+/-8.01, respectively) were not significantly different from those obtained after group culture (P<0.05). Though, individual culture in a cumulus cell conditioned medium significantly reduced both the cleavage (59.0%) and blastocyst rates (6.3%). These results demonstrate that single culture of bovine zygotes can be fully sustained by coculture with cumulus cells in a low oxygen environment; implementation of these findings in our IVP system produced blastocysts comparable in quantity and quality to those obtained by group culture. These results were consistently achieved after acquiring experience and expertise in the handling of single zygotes. PMID:18962875

Goovaerts, I G F; Leroy, J L M R; Van Soom, A; De Clercq, J B P; Andries, S; Bols, P E J

2009-03-15

294

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

295

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

PubMed Central

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

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

2014-01-01

296

Addition of l-ascorbic acid to culture and vitrification media of IVF porcine blastocysts improves survival and reduces HSPA1A levels of vitrified embryos.  

PubMed

The aim of the present study was to determine the effect of l-ascorbic acid on embryo quality and gene expression of porcine blastocysts after supplementations of in vitro culture medium and/or vitrification-warming media. Embryo quality, in terms of total cell number (TCN), DNA fragmentation and peroxide levels, together with the relative transcript abundance of BCL-2 associated X protein (BAX), BCL2-like 1 (BCL2L1), POU class 5 homeobox 1 (POU5F1) and heat shock protein 70 (HSPA1A), was analysed. In Experiment 1, gene expression and embryo quality of fresh blastocysts were evaluated after culture with or without l-ascorbic acid; no significant differences were observed between the groups. In Experiment 2, blastocysts cultured with or without l-ascorbic acid were vitrified using two different vitrification solutions, supplemented or not with l-ascorbic acid. Supplementation of culture and vitrification media significantly enhanced survival rates and reduced peroxide levels. No significant differences in TCN, DNA fragmentation and BAX, BCL2L1 and POU5F1 expression were found in vitrified blastocysts among experimental groups. Vitrification procedures increase HSPA1A transcript abundance, but this increase was significantly lower in embryos cultured and/or vitrified with l-ascorbic acid. Thus, supplementing culture and/or vitrification media with l-ascorbic acid enhances survival rates of porcine blastocysts, suggesting a relationship with HSPA1A expression. PMID:25322209

Castillo-Martín, Miriam; Yeste, Marc; Soler, Albert; Morató, Roser; Bonet, Sergi

2014-04-17

297

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

PubMed

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

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

2012-03-27

298

Embryonic Stem Cells Derived from In Vivo or In Vitro-Generated Murine Blastocysts Display Similar Transcriptome and Differentiation Potential  

PubMed Central

The use of assisted reproductive technologies (ART) such as in vitro fertilization (IVF) has resulted in the birth of more than 5 million children. While children conceived by these technologies are generally healthy, there is conflicting evidence suggesting an increase in adult-onset complications like glucose intolerance and high blood pressure in IVF children. Animal models indicate similar potential risks. It remains unclear what molecular mechanisms may be operating during in vitro culture to predispose the embryo to these diseases. One of the limitations faced by investigators is the paucity of the material in the preimplantation embryo to test for molecular analysis. To address this problem, we generated mouse embryonic stem cells (mESC) from blastocysts conceived after natural mating (mESCFB) or after IVF, using optimal (KSOM + 5% O2; mESCKAA) and suboptimal (Whitten’s Medium, + 20% O2, mESCWM) conditions. All three groups of embryos showed similar behavior during both derivation and differentiation into their respective mESC lines. Unsupervised hierarchical clustering of microarray data showed that blastocyst culture does not affect the transcriptome of derived mESCs. Transcriptomic changes previously observed in the inner cell mass (ICM) of embryos derived in the same conditions were not present in mESCs, regardless of method of conception or culture medium, suggesting that mESC do not fully maintain a memory of the events occurring prior to their derivation. We conclude that the fertilization method or culture media used to generate blastocysts does not affect differentiation potential, morphology and transcriptome of mESCs. PMID:25723476

Simbulan, Rhodel K.; Di Santo, Marlea; Liu, Xiaowei; Lin, Wingka; Donjacour, Annemarie; Maltepe, Emin; Shenoy, Archana; Borini, Andrea; Rinaudo, Paolo

2015-01-01

299

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

PubMed Central

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

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

2014-01-01

300

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

PubMed

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

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

2014-03-01

301

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

302

Production of lion (Panthera leo) blastocysts after in vitro maturation of oocytes and intracytoplasmic sperm injection.  

PubMed

Assisted reproductive techniques are becoming widely applied to the breeding of endangered species, but establishing reliable protocols for the production of embryos in vitro is challenging because of the scarcity of sample material. In our study, we applied an assisted reproductive technique protocol for IVM and intracytoplasmic sperm injection (ICSI), developed in the domestic cat, to oocytes retrieved from ovaries of four 2-year-old lionesses (Panthera leo) eight hours postmortem. In total, 68 cumulus-oocyte complexes of good quality were randomly distributed and cultured for 32 to 34 hours in two different maturation culture media, consisting of Medium 199 with Earle's salts, 3 mg/mL BSA, 0.1 mg/mL cysteine, 1.4 mg/mL sodium pyruvate, 0.6 mg/mL sodium lactate, 0.15 mg/mL l-glutamine, and 0.055 mg/mL gentamicin. Hormonal supplementation of IVM_1 was 0.02 IU/mL FSH and 0.05 IU/mL LH; IVM_2 consisted of 1.64 IU/mL FSH, 1.06 IU/mL LH, and 1 ?g/mL 17ß-estradiol. Differences in hormonal supplementation did not produce significant differences in oocyte maturation rates, which were 39.4% in IVM_1 and 34.3% in IVM_2. Matured oocytes were microinjected with homologous frozen-thawed spermatozoa, and subsequent cleavage rates were 30.8% and 58.3%, respectively. Half of the embryos derived from oocytes matured in IVM_1 developed into blastocysts, whereas only 28.6% of embryos from oocytes matured in IVM_2 reached the blastocyst stage. Morula stages were present from Day 6 onward, and blastocyst stages from Day 9 on, indicating a slower developmental speed in comparison with domestic cats. This is the first report of in vitro-produced blastocysts using ICSI in the lion, and the results report that IVM and ICSI can be successfully performed with cumulus-oocyte complexes retrieved from ovaries after eight hours of shipping, obtaining competent embryos in culture. PMID:25586639

Fernandez-Gonzalez, Lorena; Hribal, Romy; Stagegaard, Julia; Zahmel, Jennifer; Jewgenow, Katarina

2015-04-01

303

Facile synthetic access to rhenium(II) complexes: activation of carbon-bromine bonds by single-electron transfer.  

PubMed

The five-coordinated Re(I) hydride complexes [Re(Br)(H)(NO)(PR(3))(2)] (R=Cy 1 a, iPr 1 b) were reacted with benzylbromide, thereby affording the 17-electron mononuclear Re(II) hydride complexes [Re(Br)(2)(H)(NO)(PR(3))(2)] (R=Cy 3 a, iPr 3 b), which were characterized by EPR, cyclic voltammetry, and magnetic susceptibility measurements. In the case of dibromomethane or bromoform, the reaction of 1 afforded Re(II) hydrides 3 in addition to Re(I) carbene hydrides [Re(=CHR(1))(Br)(H)(NO)(PR(3))(2)] (R(1)=H 4, Br 5; R=Cy a, iPr b) in which the hydride ligand is positioned cis to the carbene ligand. For comparison, the dihydrogen Re(I) dibromide complexes [Re(Br)(2)(NO)(PR(3))(2)(eta(2)-H(2))] (R=Cy 2 a, iPr 2 b) were reacted with allyl- or benzylbromide, thereby affording the monophosphine Re(II) complex salts [R(3)PCH(2)R'][Re(Br)(4)(NO)(PR(3))] (R'=-CH=CH(2) 6, Ph 7). The reduction of Re(II) complexes has also been examined. Complex 3 a or 3 b can be reduced by zinc to afford 1 a or 1 b in high yield. Under catalytic conditions, this reaction enables homocoupling of benzylbromide (turnover frequency (TOF): 3 a 150, 3 b 134 h(-1)) or allylbromide (TOF: 3 a 575, 3 b 562 h(-1)). The reaction of 6 a and 6 b with zinc in acetonitrile affords in good yields the monophosphine Re(I) complexes [Re(Br)(2)(NO)(MeCN)(2)(PR(3))] (R=Cy 8 a, iPr 8 b), which showed high catalytic activity toward highly selective dehydrogenative silylation of styrenes (maximum TOF of 61 h(-1)). Single-electron transfer (SET) mechanisms were proposed for all these transformations. The molecular structures of 3 a, 6 a, 6 b, 7 a, 7 b, and 8 a were established by single-crystal X-ray diffraction studies. PMID:20066700

Jiang, Yanfeng; Blacque, Olivier; Fox, Thomas; Frech, Christian M; Berke, Heinz

2010-02-15

304

Interspecies nuclear transfer of Tibetan antelope using caprine oocyte as recipient.  

PubMed

Interspecies nuclear transfer is an invalulable tool for studying nucleus-cytoplasm interactions; and at the same time, it provides a possible alternative to clone endangered animals whose oocytes are difficult to obtain. In the present study, we investigated the possibility of cloning Tibetan antelope embryos using abattoir-derived caprine oocytes as recipients. Effects of culture conditions, enucleation timing, and donor cell passages on the in vitro development of Tibetan antelope-goat cloned embryos were studied. Maternal to zygotic transition timing of interspecies Tibetan antelope embryos was also investigated using two types of cloned embryos, Tibetan antelope-rabbit and Tibetan antelope-goat embryos. Our results indicate that: (1) goat oocyte is able to reprogram somatic cells of different genus and supports development to blastocyst in vitro. (2) Coculture system supported the development of Tibetan antelope-goat embryos to blastocyst rate stage (4.0%), while CR1aa alone did not. (3) When MII phase enucleated caprine cytoplast and TII phase enucleated caprine cytoplast were used as recipients, the fusion rate and blastocyst rate of hybrid embryos were not statistically different (73.9% vs. 67.4%; 4.0% vs. 1.1%). (4) When donor cells at 3-8 passages were used, 2.9% hybrid embryos developed to blastocysts, while none developed to blastocysts when cells at 10-17 passages were used. (5) There may be a morula-to-blastocyst block for Tibetan antelope-goat, while there may be an 8- to 16-cell block for Tibetan antelope-rabbit embryos. PMID:17034044

Zhao, Zhen-Jun; Li, Rui-Chang; Cao, Heng-Hua; Zhang, Quan-Jun; Jiang, Man-Xi; Ouyang, Ying-Chun; Nan, Chang-Long; Lei, Zi-Li; Song, Xiang-Fen; Sun, Qing-Yuan; Chen, Da-Yuan

2007-04-01

305

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

PubMed

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

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

2014-10-17

306

Accumulative charge separation for solar fuels production: coupling light-induced single electron transfer to multielectron catalysis.  

PubMed

The conversion and storage of solar energy into a fuel holds promise to provide a significant part of the future renewable energy demand of our societies. Solar energy technologies today generate heat or electricity, while the large majority of our energy is used in the form of fuels. Direct conversion of solar energy to a fuel would satisfy our needs for storable energy on a large scale. Solar fuels can be generated by absorbing light and converting its energy to chemical energy by electron transfer leading to separation of electrons and holes. The electrons are used in the catalytic reduction of a cheap substrate with low energy content into a high-energy fuel. The holes are filled by oxidation of water, which is the only electron source available for large scale solar fuel production. Absorption of a single photon typically leads to separation of a single electron-hole pair. In contrast, fuel production and water oxidation are multielectron, multiproton reactions. Therefore, a system for direct solar fuel production must be able to accumulate the electrons and holes provided by the sequential absorption of several photons in order to complete the catalytic reactions. In this Account, the process is termed accumulative charge separation. This is considerably more complicated than charge separation on a single electron level and needs particular attention. Semiconductor materials and molecular dyes have for a long time been optimized for use in photovoltaic devices. Efforts are made to develop new systems for light harvesting and charge separation that are better optimized for solar fuel production than those used in the early devices presented so far. Significant progress has recently been made in the discovery and design of better homogeneous and heterogeneous catalysts for solar fuels and water oxidation. While the heterogeneous ones perform better today, molecular catalysts based on transition metal complexes offer much greater tunability of electronic and structural properties, they are typically more amenable to mechanistic analysis, and they are small and therefore require less material. Therefore, they have arguably greater potential as future efficient catalysts but must be efficiently coupled to accumulative charge separation. This Account discusses accumulative charge separation with focus on molecular and molecule-semiconductor hybrid systems. The coupling between charge separation and catalysis involves many challenges that are often overlooked, and they are not always apparent when studying water oxidation and fuel formation as separate half-reactions with sacrificial agents. Transition metal catalysts, as well as other multielectron donors and acceptors, cycle through many different states that may quench the excited sensitizer by nonproductive pathways. Examples where this has been shown, often with ultrafast rates, are reviewed. Strategies to avoid these competing energy-loss reactions and still obtain efficient coupling of charge separation to catalysis are discussed. This includes recent examples of dye-sensitized semiconductor devices with molecular catalysts and dyes that realize complete water splitting, albeit with limited efficiency. PMID:25675365

Hammarström, Leif

2015-03-17

307

Physical mechanisms of heat transfer during single bubble nucleate boiling of FC72 under saturation conditions-I. Experimental investigation  

Microsoft Academic Search

This paper is the first of a two-part study concerning the dynamics of heat transfer during nucleation process of saturated FC-72 liquid. Experimental results discussed in this paper provide new physical insight on the nature of heat transfer events at the nucleation site during the nucleate boiling process. The thermal field underneath a bubble during the boiling of FC-72 was

Saeed Moghaddam; Ken Kiger

2009-01-01

308

Physical mechanisms of heat transfer during single bubble nucleate boiling of FC72 under saturation conditions. II: Theoretical analysis  

Microsoft Academic Search

This paper is the second part of a two-part study concerning the dynamics of heat transfer during the nucleation process of FC-72 liquid. The experimental findings on the nature of different heat transfer mechanisms involved in the nucleation process were discussed in part I. In this paper, the experimental results are compared with the existing boiling models. The boiling models

Saeed Moghaddam; Ken Kiger

2009-01-01

309

Interplay of hole transfer and host-guest interaction in a molecular dyad and triad: ensemble and single-molecule spectroscopy and sensing applications.  

PubMed

A new molecular dyad consisting of a Cy5 chromophore and ferrocene (Fc) and a triad consisting of Cy5, Fc, and ?-cyclodextrin (CD) are synthesized and their photophysical properties investigated at both the ensemble and single-molecule levels. Hole transfer efficiency from Cy5 to Fc in the dyad is reduced upon addition of CD. This is due to an increase in the Cy5-Fc separation (r) when the Fc is encapsulated in the macrocyclic host. On the other hand, the triad adopts either a Fc-CD inclusion complex conformation in which hole transfer quenching of the Cy5 by Fc is minimal or a quasi-static conformation with short r and rapid charge transfer. Single-molecule fluorescence measurements reveal that r is lengthened when the triad molecules are deposited on a glass substrate. By combining intramolecular charge transfer and competitive supramolecular interaction, the triad acts as an efficient chemical sensor to detect different bioactive analytes such as amantadine hydrochloride and sodium lithocholate in aqueous solution and synthetic urine. PMID:25538048

Wu, Xiangyang; Liu, Fang; Wells, Kym L; Tan, Serena L J; Webster, Richard D; Tan, Howe-Siang; Zhang, Dawei; Xing, Bengang; Yeow, Edwin K L

2015-02-16

310

Pulsed Green-Laser Annealing for Single-Crystalline Silicon Film Transferred onto Silicon wafer and Non-alkaline Glass by Hydrogen-Induced Exfoliation  

Microsoft Academic Search

A single-crystalline Si film was transferred onto a Si wafer and non-alkaline glass by hydrogen-induced exfoliation and the effect of pulsed green-laser annealing was investigated. Above a laser energy of 1285 mJ\\/cm2, the crystallinity of the Si film was recovered both on the Si wafer and the glass. The linewidth of micro-Raman spectra of the Si film on the Si

Norihito Kawaguchi; Ryusuke Kawakami; Ken-ichiro Nishida; Naoya Yamamoto; Miyuki Masaki; Atsushi Yoshinouchi

2007-01-01

311

Development and verification of general correlations for pressure drop and heat transfer in single-phase turbulent flow in enhanced tubes  

Microsoft Academic Search

General correlations are developed and verified for friction factor and heat-transfer coefficient for single-phase turbulent flow in internally augmented tubes. Data from frequently referred investigations were gathered for a wide range of tube parameters with ed, 0.01 to 0.2; pd, 0.1 to 7.0; ?90, 0.3 to 1.0, and flow parameters Re, 5000 to 250,000 and Pr, 0.66 to 37.6. The

A. E. Bergles

1996-01-01

312

Evaporation heat transfer coefficient in single circular small tubes for flow natural refrigerants of C 3H 8, NH 3, and CO 2  

Microsoft Academic Search

An experimental study of evaporation heat transfer coefficients for single circular small tubes was conducted for the flow of C3H8, NH3, and CO2 under various flow conditions. The test matrix encompasses the entire quality range from 0.0 to 1.0, mass fluxes from 50 to 600kgm?2s?1, heat fluxes from 5 to 70kWm?2, and saturation temperatures from 0 to 10°C. The test

A. S. Pamitran; Kwang-Il Choi; Jong-Taek Oh; Nasruddin

2011-01-01

313

Electronic absorption and luminescence spectroscopic studies of kyanite single crystals: differentiation between excitation of FeTi charge transfer and Cr 3+ dd transitions  

Microsoft Academic Search

A selected set of five different kyanite samples was analysed by electron microprobe and found to contain chromium between <0.001 and 0.055 per formula unit (pfu). Polarized electronic absorption spectroscopy on oriented single crystals,\\u000a R1, R2-sharp line luminescence and spectra of excitation of ?3- and ?4-components of R1-line of Cr3+-emission had the following results: (1) The Fe2+–Ti4+ charge transfer in

A. N. Platonov; A. N. Tarashchan; K. Langer; M. Andrut; G. Partzsch; S. S. Matsyuk

1998-01-01

314

Placental transfer and pharmacokinetics of a single oral dose of [14C]p-nitrophenol in rats.  

PubMed

The pharmacokinetics and placental transfer of a single oral dose of 100 mg/kg (10 microCi/kg, 16% of acute oral LD50) of uniformly phenyl-labeled [14C]p-nitrophenol were investigated in pregnant Sprague-Dawley rats at 14-18 days of gestation. Three animals were killed on gestation day 18, at 0.5, 1, 2, 4, 12, 24, and 48 h after dosing. Radioactivity was rapidly absorbed and distributed throughout the maternal and fetal tissues. The gastrointestinal tract contents retained 20% and 2% of the dose at 0.5 h and 4 h after dosing. The peak maternal plasma concentration of radioactivity (microg p-nitrophenol equivalent/ml) was 7.17 compared with 0.37 for fetal plasma at 0.5 h. Maximum concentration of radioactivity (microg p-nitrophenol equivalent/g fresh tissue) was detected in most tissues 0.5 h after dosing and was in descending order: kidney 23.27, liver 12.37, placenta 3.56, fetus 2.17, and brain 1.99. Radioactivity was eliminated from plasma and all tissues beiexponentially. The half-lives of elimination of 14C were 34.65 h and 69.30 h for maternal and fetal plasma, respectively. p-Nitrophenol, detected by HPLC, was the major compound identified in plasma and tissues. While p-nitrophenol disappeared biphasically from maternal plasma and kidney, it was eliminated monophasically from brain, placenta, and liver. p-Nitrocatechol and p-aminophenol were detected in the liver with peak concentrations at 0.5 h of 1.13 and 1.00 microg/g fresh tissue, respectively. While the change in the concentration of p-nitrocatechol with time was monophasic, that of p-aminophenol showed a biphasic pattern with elimination half-lives of 1.93 h and 4.95 h, respectively. Radioactivity was rapidly excreted in the urine mostly as polar metabolites, while only 3% of the dose was recovered in the feces. Radioactive materials excreted in the urine comprised: glucuronides 4%, sulfates 8%, hot-acid hydrolysates 11%, nonconjugated compounds 16%, and water-soluble metabolites 61%. This study demonstrated that although orally administered p-nitrophenol is a rapidly absorbed and excreted compound, it is transported to the maternal brain and the fetus and may pose a health risk following exposure to toxic doses during pregnancy. PMID:11043494

Abu-Qare, A W; Brownie, C F; Abou-Donia, M B

2000-09-01

315

Separation of CO 2 by single and mixed aqueous amine solvents in membrane contactors: fluid flow and mass transfer modeling  

Microsoft Academic Search

Removal of carbon dioxide from gas mixtures is of vital importance for the control of greenhouse gas emission. This study\\u000a presents a numerical simulation using computational fluid dynamics of mass and momentum transfer in hollow-fiber membrane\\u000a contactors. The simulation was conducted for physical and chemical absorption of CO2. A mass transfer model was developed to study CO2 transport through hollow-fiber

Saeed Shirazian; Azam Marjani; Mashallah Rezakazemi

316

Three-color Förster resonance energy transfer within single FOF1-ATP synthases: monitoring elastic deformations of the rotary double motor in real time  

NASA Astrophysics Data System (ADS)

Catalytic activities of enzymes are associated with elastic conformational changes of the protein backbone. Förster-type resonance energy transfer, commonly referred to as FRET, is required in order to observe the dynamics of relative movements within the protein. Förster-type resonance energy transfer between two specifically attached fluorophores provides a ruler with subnanometer resolution between 3 and 8 nm, submillisecond time resolution for time trajectories of conformational changes, and single-molecule sensitivity to overcome the need for synchronization of various conformations. FOF1-ATP synthase is a rotary molecular machine which catalyzes the formation of adenosine triphosphate (ATP). The Escherichia coli enzyme comprises a proton driven 10 stepped rotary FO motor connected to a 3-stepped F1 motor, where ATP is synthesized. This mismatch of step sizes will result in elastic deformations within the rotor parts. We present a new single-molecule FRET approach to observe both rotary motors simultaneously in a single FOF1-ATP synthase at work. We labeled this enzyme with three fluorophores, specifically at the stator part and at the two rotors. Duty cycle-optimized with alternating laser excitation, referred to as DCO-ALEX, allowed to control enzyme activity and to unravel associated transient twisting within the rotors of a single enzyme during ATP hydrolysis and ATP synthesis. Monte Carlo simulations revealed that the rotor twisting is larger than 36 deg.

Ernst, Stefan; Düser, Monika G.; Zarrabi, Nawid; Börsch, Michael

2012-01-01

317

Patient-Specific Embryonic Stem Cells Derived from Human SCNT Blastocysts  

Microsoft Academic Search

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

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

2005-01-01

318

Effect of ?-tocopherol supplementation on in vitro maturation of sheep oocytes and in vitro development of preimplantation sheep embryos to the blastocyst stage  

PubMed Central

Purpose To determine the effects of ?-tocopherol supplementation to oocyte maturation media and embryo culture media on the yield of ovine embryos. Methods ?-tocopherol, at concentrations of 0, 50, 100, 200, 400 and 500 µM was supplemented to ovine oocyte or embryo culture media and cultured at 5% or 20% O2 levels. Percentages of cleavage, morula and blastocyst, total cell count and comet assay were taken as indicators of developmental competence of embryos. Results 200 µM ?-tocopherol in embryo culture medium at 20% O2 level significantly increased the rates of cleavage (P?blastocyst (P?blastocyst total cell number (P?blastocyst formation were also significantly higher in 100 µM (P?

Shankar, Madhira Bhawani; Munuswamy, Deecaraman

2010-01-01

319

Advanced oviductal development, transport to the preferred implantation site, and attachment of the blastocyst in captive-bred, short-tailed fruit bats, Carollia perspicillata  

Microsoft Academic Search

The final stages of embryonic development in the oviduct, transport of the embryo to the uterus, and the initial stages of implantation have been examined in captive-bred Carollia perspicillata at the light and electron microscopic levels. Development progressed to the expanded, zona pellucida-free, blastocyst stage in the oviduct. The abundance of microvilli on the exterior of the trophoblast varied with

Sergio F. Oliveira; John J. Rasweiler; Nilima K. Badwaik

2000-01-01

320

Deletion of Mylk1 in Oocytes Causes Delayed Morula-to-Blastocyst Transition and Reduced Fertility Without Affecting Folliculogenesis and Oocyte Maturation in Mice.  

PubMed

The mammalian oocyte undergoes two rounds of asymmetric cell divisions during meiotic maturation and fertilization. Acentric spindle positioning and cortical polarity are two major factors involved in asymmetric cell division, both of which are thought to depend on the dynamic interaction between myosin II and actin filaments. Myosin light chain kinase (MLCK), encoded by the Mylk1 gene, could directly phosphorylate and activate myosin II. To determine whether MLCK was required for oocyte asymmetric division, we specifically disrupted the Mylk1 gene in oocytes by Cre-loxP conditional knockout system. We found that Mylk1 mutant female mice showed severe subfertility. Unexpectedly, contrary to previously reported in vitro findings, our data showed that oocyte meiotic maturation including spindle organization, polarity establishment, homologous chromosomes separation, and polar body extrusion were not affected in Mylk1(fl/fl);GCre(+) females. Follicular development, ovulation, and early embryonic development up to compact morula occurred normally in Mylk1(fl/fl);GCre(+) females, but deletion of MLCK caused delayed morula-to-blastocyst transition. More than a third of embryos were at morula stage at 3.5 Days Postcoitum in vivo. The delayed embryos could develop further to early blastocyst stage in vitro on Day 4 when most control embryos reached expanded blastocysts. Our findings provide evidence that MLCK is linked to timely blastocyst formation, though it is dispensable for oocyte meiotic maturation. PMID:25761595

Liang, Qiu-Xia; Zhang, Qing-Hua; Qi, Shu-Tao; Wang, Zhong-Wei; Hu, Meng-Wen; Ma, Xue-Shan; Zhu, Min-Sheng; Schatten, Heide; Wang, Zhen-Bo; Sun, Qing-Yuan

2015-04-01

321

No evidence of association between blastocyst aneuploidy and morphokinetic assessment in a selected population of poor-prognosis patients: a longitudinal cohort study.  

PubMed

Recent studies involving a limited number of patients have indicated a correlation between aneuploidy and various morphokinetic parameters during preimplantation development. The results among different groups, however, have been inconsistent in identifying the parameters that are able to predict chromosomal abnormalities. The aim of this study was to investigate whether aneuploidy of human blastocysts was detectable by specific morphokinetic parameters in patients at increased risk of aneuploidy because of advanced maternal age, history of unsuccessful IVF treatments, or both. A longitudinal cohort study was conducted using 455 blastocysts from 138 patients. Morphokinetic features of preimplantation development were detected in a timelapse incubator. Blastocysts were subjected to trophectodermal biopsy and comprehensive chromosomal screening. Analyses were conducted by means of logistic mixed-effects models, with a subject-specific intercept. No statistical correlation between 16 commonly detected morphokinetic characteristics of in-vitro embryo development and aneuploidy was found. Results suggest that morphokinetic characteristics cannot be used to select euploid blastocysts in poor-prognosis patients regarded as candidates for pre-implantation genetic screening. PMID:25458852

Rienzi, L; Capalbo, A; Stoppa, M; Romano, S; Maggiulli, R; Albricci, L; Scarica, C; Farcomeni, A; Vajta, G; Ubaldi, F M

2015-01-01

322

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

323

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

324

Alleviation of the '2-cell block' and development to the blastocyst of CF1 mouse embryos: role of amino acids, EDTA and physical parameters.  

PubMed

The role of amino acids, ethylenediaminetetraacetic acid (EDTA), transferrin, oxygen, glucose, glutamine, taurine and ammonium in CF1 mouse zygote development in culture was examined. Non-essential amino acids and glutamine were shown to alleviate the 2-cell block in culture, and acted in synergy with EDTA to facilitate development to the blastocyst stage. In the presence of amino acids and EDTA, transferrin conferred no beneficial effect. Development of zygotes was significantly impaired if amino acids were removed from the collection medium, even when they were subsequently cultured in the presence of amino acids. Zygote development to the blastocyst stage was significantly improved when modular incubator chambers were used compared to using a conventional incubator, and when an oxygen concentration of 7% was used as opposed to 20%. Addition of taurine to medium containing non-essential amino acids had no effect on embryo development, whereas the removal of glutamine and/or glucose from the culture medium significantly reduced blastocyst cell number. Removal of glucose from the culture medium also resulted in a significant decrease in implantations. Ammonium, generated from the breakdown of amino acids, significantly reduced blastocyst development. EDTA was found to confer its beneficial effects during the first 48 h of culture, and indeed was inhibitory during the second 48 h, resulting in loss of subsequent viability. In summary, the data demonstrate that development of CF1 zygotes to the blastocyst stage is readily achievable. In the presence of non-essential amino acids and glutamine the removal of glucose is detrimental to CF1 mouse embryo development in culture and reduces subsequent viability. Optimal development and maintenance of viability requires more than one culture medium to support the preimplantation period. PMID:9021376

Gardner, D K; Lane, M

1996-12-01

325

Identification of caspase-3 and caspase-activated deoxyribonuclease in rat blastocysts and their implication in the induction of chromatin degradation (but not nuclear fragmentation) by high glucose.  

PubMed

Previous investigations have shown that maternal diabetes impairs rodent embryo development during the earliest phase of gestation. Exposure to high concentrations of glucose before implantation results in a decrease in the number of cells per embryo and in a concomitant increase in two nuclear markers of apoptosis, chromatin degradation and nuclear fragmentation. In the present study, we show that two intracellular effectors of apoptosis, caspase-3 and caspase-activated deoxyribonuclease (CAD), are involved in the embryotoxicity of high glucose. Using reverse transcription-polymerase chain reaction and immunocytochemistry, we first demonstrated that these two effectors were expressed in rat blastocysts. The two effectors were detected in all the cells of the blastocysts and the immuno-signals were excluded from the nuclei. Rat blastocysts were incubated for 24 h in either 6 mM or 28 mM glucose in the presence or absence of specific inhibitors (DEVD-CHO [10 microM] against caspase-3 and aurin [1 microM] against CAD). After incubation, blastocysts were examined for the proportion of nuclei showing signs of chromatin degradation or nuclear fragmentation. Addition of DEVD-CHO or aurin was found to inhibit the increase in chromatin degradation induced by high glucose. None of these two inhibitors prevented the increase in nuclear fragmentation triggered by excess glucose. Our data indicate that chromatin degradation and nuclear fragmentation are two nuclear damages that are induced separately by high glucose in rat blastocysts. Chromatin degradation is apparently mediated by the activation of caspase-3 and CAD. PMID:11159358

Hinck, L; Van Der Smissen, P; Heusterpreute, M; Donnay, I; De Hertogh, R; Pampfer, S

2001-02-01

326

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

PubMed Central

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

Paul, Soumen; Knott, Jason G.

2014-01-01

327

Bovine blastocyst-derived trophectoderm and endoderm cell cultures: interferon tau and transferrin expression as respective in vitro markers.  

PubMed

Continuous cultures of bovine trophectoderm (CT-1 and CT-5) and bovine endoderm (CE-1 and CE-2) were initiated and maintained on STO feeder cells. CT-1 and CT-5 were derived from the culture of intact, 10- to 11-day in vitro-produced blastocysts. CE-1 and CE-2 were derived from the culture of immunodissected inner cell masses of 7- to 8-day in vitro-produced blastocysts. The cultures were routinely passaged by physical dissociation. Although morphologically distinct, the trophectoderm and endoderm both grew as cell sheets of polarized epithelium (dome formations) composed of approximately cuboidal cells. Both cell types, particularly the endoderm, grew on top of the feeder cells for the most part. Trophectoderm cultures grew faster, relative to endoderm, in large, rapidly extending colonies of initially flat cells with little or no visible lipid. The endoderm, in contrast, grew more slowly as tightly knit colonies with numerous lipid vacuoles in the cells at the colony centers. Ultrastructure analysis revealed that both cell types were connected by desmosomes and tight junctional areas, although these were more extensive in the trophectoderm. Endoderm was particularly rich in rough endoplasmic reticulum and Golgi apparatus indicative of cells engaged in high protein production and secretion. Interferon tau expression was specific to trophectoderm cultures, as demonstrated by reverse transcription-polymerase chain reaction, Western blot, and antiviral activity; and this property may act as a marker for this cell type. Serum protein production specific to endoderm cultures was demonstrated by Western blot; this attribute may be a useful marker for this cell type. This simple coculture method for the in vitro propagation of bovine trophectoderm and endoderm provides a system for assessing their biology in vitro. PMID:10642558

Talbot, N C; Caperna, T J; Edwards, J L; Garrett, W; Wells, K D; Ealy, A D

2000-02-01

328

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

E-print Network

Available online 20 August 2004 Abstract Surface enhanced Raman spectroscopy is applied to study single level [4]. Among other techniques, surface enhanced Raman spectroscopy (SERS) allows one to reach single oscillating across the molecule and the metal surface, could provide some insight on both the surface enhanced

Tuscia, Università Degli Studi Della

329

Fabrication of N-channel single crystalline silicon (100) thin-film transistors on glass substrate by meniscus force-mediated layer transfer technique  

NASA Astrophysics Data System (ADS)

We propose a novel low-temperature layer transfer of single crystalline silicon (100) to glass substrate using meniscus force and midair cavity structure. Local transfer of thermally-oxidized silicon-on-insulator (SOI) layer to glass was successfully carried out at 80 °C. N-channel thin-film transistor (TFT) fabricated on glass at 300 °C showed a field-effect mobility of 1097 cm2 V?1 s?1, a threshold voltage of 1.1 V and a subthreshold swing value of 78 mV/dec. Raman scattering analysis suggests such a high mobility of TFT is originated from tensile strain introduced after gate SiO2 film deposition.

Akazawa, Muneki; Sakaike, Kohei; Nakamura, Shogo; Higashi, Seiichiro

2014-10-01

330

The effect of sugar removal on the structure of the Fc region of an IgG antibody as observed with single molecule Förster Resonance Energy Transfer.  

PubMed

The deglycosylation of immunoglobulin G (IgG) antibodies leads to a diminished immune response. This reduction in immune response is thought to arise from weakened binding of IgG antibodies to effector molecules as a result of a conformational change in the antibody. The nature of this structural alteration is uncertain due to the conflicting results obtained from different experimental methods. We have examined the impact of deglycosylation by the endoglycosidase PNGase F on the structure of the Fc region of a human IgG antibody using single molecule Förster Resonance Energy Transfer (FRET). The FRET efficiency histograms obtained indicate that the structure of the Fc region becomes more flexible upon deglycosylation. This is demonstrated by a change in the width of the energy transfer efficiency peak, which increases from 0.19 ± 0.02 to 0.6 ± 0.1 upon deglycosylation. PMID:24813166

Kelliher, Michael T; Jacks, Ramiah D; Piraino, Mark S; Southern, Cathrine A

2014-08-01

331

Effect of maternal obesity on estrous cyclicity, embryo development and blastocyst gene expression in a mouse model  

PubMed Central

STUDY QUESTION Does maternal obesity affect estrous cyclicity, embryo development and blastocyst gene expression in mice? SUMMARY ANSWER Maternal obesity alters estrous cyclicity and causes the down-regulation of two key metabolite receptors (Slc2a1 and Ldlr) in blastocysts recovered from diet-induced obese females, but embryo development is not affected. WHAT IS KNOWN ALREADY Maternal obesity reduces fertility because of effects in the periconception period, but its negative influence is on estrous cyclicity, oocyte quality or embryo development. STUDY DESIGN, SIZE AND DURATION This was a randomized study based on a mouse model for obesity. Twenty-one outbred NIH Swiss mice were used and obesity was induced by a diet high in fat administered for 12 weeks prior to breeding to control males. MATERIAL, SETTING AND METHODS Females were fed either a control diet (C, n = 9) or a diet high in fat [diet-induced obesity (DiO), n = 12] for 12 weeks, and were then co-housed with fertile males. Mice that failed to breed during 20 consecutive days were considered infertile. Control and diet-induced obese females that demonstrated vaginal plugs were euthanized 3.5 days after mating, blood was sampled for glucose and hormone measurements, corpora lutea counted and embryos recovered; the relative mRNA abundance of 11 candidate genes was determined in blastocysts by qPCR. MAIN RESULTS AND THE ROLE OF CHANCE Five DiO females failed to breed and displayed anovulatory ovaries (DiOI), whereas the other seven DiO females (DiOF) could breed, albeit over an extended period compared with controls. DiOF weighed significantly less than DiOI. Both groups had elevated serum insulin compared with C, although blood glucose level was only significantly higher than that in controls in the infertile DiOI group. Adiponectin was lower in the DiOI and leptin higher in both the DiOI and DiOF mice than in C. DiOF ovulated the same number of oocytes as C, and embryo development to blastocyst was normal. The expression of genes encoding metabolic hormone receptors (Insr, Igf1r, Igf2r, Adipor1, Adipor2 and Lepr) and key metabolic enzymes (Gapdh, Cpt1a and Sod2) did not differ between DiOF and C blastocysts, but that of metabolite receptors (Slc2a1 and Ldr) was down-regulated in DiOF. To limit the role of chance, the experiments were conducted in a defined laboratory setting with the proper controls, and the animals were randomly assigned to each experimental group. Moreover, a P-value of < 0.05 was chosen to determine whether the differences observed between the groups were statistically significant. LIMITATIONS AND REASONS FOR CAUTION The results obtained may not fully extrapolate to humans. Also, as follicular activity was not monitored while breeding, so the extended breeding period for DiOF group might be explained by behavioral abnormalities occurring in normal cycling animals. WIDER IMPLICATIONS OF THE FINDINGS DiO alters the estrous cycle in the mouse model and demonstrates a role of obesity in infertility. The data also suggest that in an outbred, genetically diverse population, such as the human, individual susceptibility to obesity and associated infertility induced by diet exists. The apparently normal development to blastocyst observed in fertile, obese females suggests that preimplantation embryos can resist potentially adverse outcomes caused by an oversupply of fatty acids and glucose under in vivo conditions. This metabolic plasticity may, in part, be due to an ability to down-regulate metabolite transporters, thereby preventing excessive nutrient uptake. STUDY FUNDING/COMPETING INTEREST(S) The research was supported by funds from the University of Missouri, grants from the National Institutes of Health and by a fellowship from the Lalor Foundation. There were no competing interests. TRIAL REGISTRATION NUMBER Not applicable. PMID:23001779

Bermejo-Alvarez, Pablo; Rosenfeld, Cheryl S.; Roberts, R. Michael

2012-01-01

332

Hydrophobic transfer of RTV silicone rubber aged in single and multiple environmental stresses and the behavior of LMW silicone fluid  

Microsoft Academic Search

This paper describes the hydrophobic transfer of unfilled room temperature vulcanized silicone rubber (RTV) resulting from UV radiation, corona discharges, high temperature, and a deposition of hydrophilic layer. The chemical and morphological structure at the surface layer and the migrating behavior of low molecular weight (LMW) silicone fluid from the bulk on to the surface top layer are investigated in

Seiji Kumagai; Noboru Yoshimura

2003-01-01

333

NUMERICAL SIMULATIONS OF DYNAMICS AND HEAT TRANSFER ASSOCIATED WITH A SINGLE BUBBLE IN THE PRESENCE OF NONCONDENSABLES  

Microsoft Academic Search

Under subcooled boiling conditions, the liquid may contain dissolved noncondensabe gases. During phase change at the bubble-liquid interface, noncondensable gases will be injected into the bubble along with vapor. Due to heat transfer into sub- cooled liquid, vapor will condense in the upper regions of the bubble and the bubble interface is impermeable to noncondens- ables. As a result, noncondensabe

Jinfeng Wu; Vijay K. Dhir

2007-01-01

334

Production of rhesus monkey cloned embryos expressing monomeric red fluorescent protein by interspecies somatic cell nuclear transfer.  

PubMed

Interspecies somatic cell nuclear transfer (iSCNT) is a promising method to clone endangered animals from which oocytes are difficult to obtain. Monomeric red fluorescent protein 1 (mRFP1) is an excellent selection marker for transgenically modified cloned embryos during somatic cell nuclear transfer (SCNT). In this study, mRFP-expressing rhesus monkey cells or porcine cells were transferred into enucleated porcine oocytes to generate iSCNT and SCNT embryos, respectively. The development of these embryos was studied in vitro. The percentage of embryos that underwent cleavage did not significantly differ between iSCNT and SCNT embryos (P>0.05; 71.53% vs. 80.30%). However, significantly fewer iSCNT embryos than SCNT embryos reached the blastocyst stage (2.04% vs. 10.19%, P<0.05). Valproic acid was used in an attempt to increase the percentage of iSCNT embryos that developed to the blastocyst stage. However, the percentages of embryos that underwent cleavage and reached the blastocyst stage were similar between untreated iSCNT embryos and iSCNT embryos treated with 2mM valproic acid for 24h (72.12% vs. 70.83% and 2.67% vs. 2.35%, respectively). These data suggest that porcine-rhesus monkey interspecies embryos can be generated that efficiently express mRFP1. However, a significantly lower proportion of iSCNT embryos than SCNT embryos reach the blastocyst stage. Valproic acid does not increase the percentage of porcine-rhesus monkey iSCNT embryos that reach the blastocyst stage. The mechanisms underling nuclear reprogramming and epigenetic modifications in iSCNT need to be investigated further. PMID:24491539

Zhu, Hai-Ying; Kang, Jin-Dan; Li, Suo; Jin, Jun-Xue; Hong, Yu; Jin, Long; Guo, Qing; Gao, Qing-Shan; Yan, Chang-Guo; Yin, Xi-Jun

2014-02-21

335

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

PubMed

The low success rate of animal cloning by somatic cell nuclear transfer (SCNT) is believed to be associated with epigenetic errors including abnormal DNA hypermethylation. Recently, we elucidated by using round spermatids that, after nuclear transfer, treatment of zygotes with trichostatin A (TSA), an inhibitor of histone deacetylase, can remarkably reduce abnormal DNA hypermethylation depending on the origins of transferred nuclei and their genomic regions [S. Kishigami, N. Van Thuan, T. Hikichi, H. Ohta, S. Wakayama. E. Mizutani, T. Wakayama, Epigenetic abnormalities of the mouse paternal zygotic genome associated with microinsemination of round spermatids, Dev. Biol. (2005) in press]. Here, we found that 5-50 nM TSA-treatment for 10 h following oocyte activation resulted in more efficient in vitro development of somatic cloned embryos to the blastocyst stage from 2- to 5-fold depending on the donor cells including tail tip cells, spleen cells, neural stem cells, and cumulus cells. This TSA-treatment also led to more than 5-fold increase in success rate of mouse cloning from cumulus cells without obvious abnormality but failed to improve ES cloning success. Further, we succeeded in establishment of nuclear transfer-embryonic stem (NT-ES) cells from TSA-treated cloned blastocyst at a rate three times higher than those from untreated cloned blastocysts. Thus, our data indicate that TSA-treatment after SCNT in mice can dramatically improve the practical application of current cloning techniques. PMID:16356478

Kishigami, Satoshi; Mizutani, Eiji; Ohta, Hiroshi; Hikichi, Takafusa; Thuan, Nguyen Van; Wakayama, Sayaka; Bui, Hong-Thuy; Wakayama, Teruhiko

2006-02-01

336

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

PubMed Central

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

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

2011-01-01

337

Transition metal and rare-earth metal atoms on single-layer graphene: Estimations of the charge transfer and adsorption energy  

NASA Astrophysics Data System (ADS)

A Hamiltonian accounting for s- and d( f)-states of adatoms has been proposed to describe adsorption of atoms of d- and f-metals on single-sheet graphene. It has been shown that s-electrons mainly contribute to the charge transfer ? n a between the adatom and graphene substrate. Analytical formulas proposed previously within the M-model of the graphene density of states are used for ? n a calculations. To estimate the adsorption energy, a simple analytical expression is proposed. Calculations are performed for 3 d-, 4 d-, 5 d-, and 4 f-adatoms. The results of calculations are compared with the data obtained by other authors.

Davydov, S. Yu.

2013-07-01

338

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

Federal Register 2010, 2011, 2012, 2013, 2014

...First-Class Mail International Packages and Rolls to Competitive...First-Class Mail International Packages (Small Packets) and...Single-Piece First-Class Mail Packages (Small Packets) and...titled ``First-Class Package International...

2012-08-17

339

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

340

Silver transfer in proustite Ag3AsS3 at high temperatures: Conductivity and single-crystal X-ray studies  

NASA Astrophysics Data System (ADS)

Single crystals of proustite Ag3AsS3 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 Ag2S deposition at the sample surface.

Ga?or, Anna; Paw?owski, Antoni; Pietraszko, Adam

2009-03-01

341

Sensitivity function analysis of gravitational wave detection with single-laser and large-momentum-transfer atomic sensors  

NASA Astrophysics Data System (ADS)

Recently, a configuration using atomic interferometers (AIs) had been suggested for the detection of gravitational waves. A new AI with some additional laser pulses for implementing large momentum transfer was also put forward, in order to reduce the effect of shot noise and laser frequency noise. We use a sensitivity function to analyze all possible configurations of the new AI and to distinguish how many momenta are transferred in a specific configuration. By analyzing the new configuration, we further explore a detection scheme for gravitational waves, in particular, that ameliorates laser frequency noise. We find that the amelioration occurs in such a scheme, but novelly, in some cases, the frequency noise can be canceled completely by using a proper data processing method. Supported by the National Natural Science Foundation of China.

Tang, Biao; Zhang, Bao-Cheng; Zhou, Lin; Wang, Jin; Zhan, Ming-Sheng

2015-03-01

342

Production of Middle White Piglets after Transfer of Embryos Produced In Vitro  

PubMed Central

The present study was conducted to examine the feasibility of in vitro embryo production and transfer technologies for producing Middle White piglets. After collection from three retired Middle White sows, a total of 222 oocytes were matured, fertilized and cultured in vitro, and a total of 50 embryos from the 4-cell to blastocyst stage were produced by the 4th or 5th day. These embryos were transferred individually into three recipients along with 5 in vivo-derived Duroc blastocysts. All of the recipients became pregnant, and they farrowed a total of 9 Middle White and 9 Duroc piglets. These results suggest that in vitro embryo production using ovaries from retired sows is useful for reproduction of pigs of pure breeds including the Middle White for breeding activities and conservation/utilization of genetic resources. PMID:24614249

MISUMI, Koji; HIRAYAMA, Yuri; SUZUKI, Misae; NAKAI, Michiko; KANEKO, Hiroyuki; NOGUCHI, Junko; KIKUCHI, Kazuhiro

2014-01-01

343

Meniscus-force-mediated layer transfer technique using single-crystalline silicon films with midair cavity: Application to fabrication of CMOS transistors on plastic substrates  

NASA Astrophysics Data System (ADS)

A novel low-temperature technique for transferring a silicon-on-insulator (SOI) layer with a midair cavity (supported by narrow SiO2 columns) by meniscus force has been proposed, and a single-crystalline Si (c-Si) film with a midair cavity formed in dog-bone shape was successfully transferred to a poly(ethylene terephthalate) (PET) substrate at its heatproof temperature or lower. By applying this proposed transfer technique, high-performance c-Si-based complementary metal–oxide–semiconductor (CMOS) transistors were successfully fabricated on the PET substrate. The key processes are the thermal oxidation and subsequent hydrogen annealing of the SOI layer on the midair cavity. These processes ensure a good MOS interface, and the SiO2 layer works as a “blocking” layer that blocks contamination from PET. The fabricated n- and p-channel c-Si thin-film transistors (TFTs) on the PET substrate showed field-effect mobilities of 568 and 103 cm2 V?1 s?1, respectively.

Sakaike, Kohei; Akazawa, Muneki; Nakagawa, Akitoshi; Higashi, Seiichiro

2015-04-01

344

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

PubMed

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

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

2007-08-16

345

Interspecies somatic cell nuclear transfer and preliminary data for horse-cow\\/mouse iSCNT  

Microsoft Academic Search

Nuclear transfer (NT) experiments in mammals have demonstrated that adult cells are genetically equivalent to early embryonic\\u000a cells and the reversal of the differentiated state of a cell to another that has characteristics of the undifferentiated embryonic\\u000a state can be defined as nuclear reprogramming. The feasiblity of interspecies somatic cell NT (iSCNT) has been demonstrated\\u000a by blastocyst formation and the

R. Tayfur Tecirlioglu; Jitong Guo; Alan O. Trounson

2006-01-01

346

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

347

In vitro developmental competence of pig nuclear transferred embryos: effects of GFP transfection, refrigeration, cell cycle synchronization and shapes of donor cells.  

PubMed

The present study was designed to evaluate the feasibility of producing pig transgenic blastocysts expressing enhanced green fluorescent protein (GFP) and to examine the effects of shape and preparation methods of donor cells on in vitro developmental ability of pig nuclear transferred embryos (NTEs). In experiment 1, the effect of GFP transfection on development of pig NTEs was evaluated. The cleavage and blastocyst rates showed no significant difference between NTEs derived from transfected and non-transfected donors. In experiment 2, the effect of different nuclear donor preparation methods on in vitro development of NTEs was examined. The cleavage rate showed no statistically significant differences among three preparation methods. The blastocyst rates of donor cells treated once at -4 degrees C and those of freshly digested cells were similar to each other (26.3% vs 17.9%). The lowest blastocyst rates (5.88%) were observed when cells cryopreserved at -196 degrees C were used as donors. In experiment 3, the effect of different cell cycle synchronization methods on the in vitro development potential of pig NTEs was evaluated. The cleavage rate of NTEs derived from cycling cells was much better than that of NTEs derived from serum-starved cells (64.4% vs 50.5%, p < 0.05), but no significant difference was observed between the the blastocyst rates of the two groups. In experiment 4, the effect of different shapes of cultured fibroblast cells on the in vitro development of pig NTEs was examined. The fusion rate for couplets derived from rough cells was poorer than that observed in couplets derived from round smooth cells (47.8% vs 76.8%, p < 0.05). However, there were no significant differences observed in the cleavage rate and blastocyst rate. In conclusion, the present study indicated that (i) refrigerated pig GFP-transfected cells could be used as donors in nuclear transfer and these NTEs could be effectively developed to blastocyst stage; (ii) serum starvation of GFP-transfected cells is not required for preimplantation development of pig NTEs; and (iii) a rough surface of GFP-transfected donor cells affects fusion rate negatively but has no influence on the cleavage rate or blastocyst rate of pig NTEs. PMID:16822335

Zhang, Yun-Hai; Pan, Deng-Ke; Sun, Xiu-Zhu; Sun, Guo-Jie; Liu, Xiao-Hui; Wang, Xiao-Bo; Tian, Xing-Hua; Li, Yan; Dai, Yun-Ping; Li, Ning

2006-08-01

348

Slow Proton Transfer Coupled to Unfolding Explains the Puzzling Results of Single-Molecule Experiments on BBL, a Paradigmatic Downhill Folding Protein  

PubMed Central

A battery of thermodynamic, kinetic, and structural approaches has indicated that the small ?-helical protein BBL folds-unfolds via the one-state downhill scenario. Yet, single-molecule fluorescence spectroscopy offers a more conflicting view. Single-molecule experiments at pH 6 show a unique half-unfolded conformational ensemble at mid denaturation, whereas other experiments performed at higher pH show a bimodal distribution, as expected for two-state folding. Here we use thermodynamic and laser T-jump kinetic experiments combined with theoretical modeling to investigate the pH dependence of BBL stability, folding kinetics and mechanism within the pH 6–11 range. We find that BBL unfolding is tightly coupled to the protonation of one of its residues with an apparent pKa of ?7. Therefore, in chemical denaturation experiments around neutral pH BBL unfolds gradually, and also converts in binary fashion to the protonated species. Moreover, under the single-molecule experimental conditions (denaturant midpoint and 279 K), we observe that proton transfer is much slower than the ?15 microseconds folding-unfolding kinetics of BBL. The relaxation kinetics is distinctly biphasic, and the overall relaxation time (i.e. 0.2–0.5 ms) becomes controlled by the proton transfer step. We then show that a simple theoretical model of protein folding coupled to proton transfer explains quantitatively all these results as well as the two sets of single-molecule experiments, including their more puzzling features. Interestingly, this analysis suggests that BBL unfolds following a one-state downhill folding mechanism at all conditions. Accordingly, the source of the bimodal distributions observed during denaturation at pH 7–8 is the splitting of the unique conformational ensemble of BBL onto two slowly inter-converting protonation species. Both, the unprotonated and protonated species unfold gradually (one-state downhill), but they exhibit different degree of unfolding at any given condition because the native structure is less stable for the protonated form. PMID:24205082

Cerminara, Michele; Campos, Luis A.; Ramanathan, Ravishankar; Muñoz, Victor

2013-01-01

349

DOI: 10.1002/cphc.201300760 Single-Molecule Metal-Induced Energy Transfer (smMIET)  

E-print Network

in space. Then these isolated molecules from each image are localized with an accuracy that is much superi] This lateral localiza- tion accuracy depends on the number of photons recorded from the single molecule, among is the number of photons col- lected from the molecule, b is the background noise level, and a is the pixel size

Enderlein, Jörg

350

Optimization of three-dimensional imaging on in vitro produced porcine blastocysts and chimeras for stem cell testing: a technology report.  

PubMed

Differential staining is an immunocytochemical staining that visualizes trophectoderm (TE) and the inner cell mass (ICM) of the blastocysts. It is used to determine the blastocyst quality, but could also be a useful tool to assess the integration site of injected cells into the early embryo. This is relevant for testing of presumed pluripotent stem cells. The gold standard for pluripotent stem cells is to test if the cells are capable of contributing to germline chimeras. Differential staining can be used to evaluate the possibility of chimeric contribution; if the cells are located in the area of the ICM they are likely to contribute to the fetus and if they are located in the area of the TE they are likely to contribute to the fetal membranes. In this article, we optimize on methods for embryo staining and mounting so that the exact location of injected stem cells within preimplantation porcine embryos can be evaluated. PMID:25567670

Secher, Jan Ole Bertelsen; Freude, Kristine K; Li, Rong; Callesen, Henrik

2015-05-01

351

Patient-specific embryonic stem cells derived from human SCNT blastocysts.  

PubMed

Patient-specific, immune-matched human embryonic stem cells (hESCs) are anticipated to be of great biomedical importance for studies of disease and development and to advance clinical deliberations regarding stem cell transplantation. Eleven hESC lines were established by somatic cell nuclear transfer (SCNT) of skin cells from patients with disease or injury into donated oocytes. These lines, nuclear transfer (NT)-hESCs, grown on human feeders from the same NT donor or from genetically unrelated individuals, were established at high rates, regardless of NT donor sex or age. NT-hESCs were pluripotent, chromosomally normal, and matched the NT patient's DNA. The major histocompatibility complex identity of each NT-hESC when compared to the patient's own showed immunological compatibility, which is important for eventual transplantation. With the generation of these NT-hESCs, evaluations of genetic and epigenetic stability can be made. Additional work remains to be done regarding the development of reliable directed differentiation and the elimination of remaining animal components. Before clinical use of these cells can occur, preclinical evidence is required to prove that transplantation of differentiated NT-hESCs can be safe, effective, and tolerated. PMID:15905366

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

2005-06-17

352

Agrobacterium-Mediated Gene Transfer Results Mainly in Transgenic Plants Transmitting T-DNA as a Single Mendelian Factor  

PubMed Central

Forty-four independent transformed tobacco plants were obtained from a cocultivation experiment with Agrobacterium tumefaciens strains carrying modified Ti-plasmids. The transformed plants were either self-fertilized or crossed with nontransformed plants or with other transformed plants. The segregation of a phenotypic marker (kanamycin resistance) in the progenies of these plants was determined. In 40 cases out of 44, the segregation of the kanamycin resistance marker is consistent with Mendelian genetics. Among these 40 clones, 35 contain a single kanamycin resistance locus. The five others segregate two independent resistance loci. In two of the single insert clones, the segregation ratio after selfing indicates that the T-DNA insertion may have caused a recessive lethal mutation. PMID:17246346

Budar, F.; Thia-Toong, L.; Van Montagu, M.; Hernalsteens, J.-P.

1986-01-01

353

Noncytopathogenic and cytopathogenic bovine viral diarrhea-mucosal disease viruses do not affect in vitro embryonic development into the blastocyst stage  

Microsoft Academic Search

Bovine oocytes enclosed within follicular epithelial (FE) cells were exposed to noncytopathogenic or cytopathogenic strains of bovine viral diarrhea-mucosal disease virus (BVD-MDV). After culture at 39°C in humidified air with 5% CO2 for 24 h, the oocytes matured and then in vitro fertilization was performed. Some of the fertilized oocytes developed into blastocysts from day 8 to day 10 (day

T. Tsuboi; T. Imada

1996-01-01

354

Isolation and Characterization of a Bovine Blastocyst-Derived Trophoblastic Cell line, BT1: Development of a Culture System in the Absence of Feeder Cell  

Microsoft Academic Search

We established a trophoblastic cell line, bovine trophoblast-1 (BT-1), derived from in vitro matured and fertilized blastocyst. While several trophoblastic cell lines have been previously reported using feeder cell, BT-1 could be cultured in the absence of feeder cell. BT-1 was cultured for more than 18 months (over 75 passage) in the absence of feeder cells, using bovine endometrial fibroblast-conditioned

A. Shimada; H. Nakano; T. Takahashi; K. Imai; K. Hashizume

2001-01-01

355

Expression and localization of membrane type matrix metal loproteinase-1 (MT1-MMP) in trophoblast cells of cultured mouse blastocysts and ectoplacental cones  

Microsoft Academic Search

Membrane type matrix metalloproteinases (MT-MMPs) possess a C-terminal transmembrane domain and are expressed on the cell membrane. It was suspected, therefore, that MTl-MMP might play an important role in the trophoblastic invasion during implantation. The patterns of expression and localization of membrane type matrix metalloproteinase-1 (MT1-MMP) were examined immunocytochemically in cultured mouse blastocysts and excised extoplacental cones (EPCs). MT1-MMP immunoreactivity

S. S. Tanaka; Y. Togooka; H. Sato; M. Seiki; H. Tojo; C. Tachia

1998-01-01

356

Addition of D-penicillamine, hypotaurine, and epinephrine (PHE) mixture to IVF medium maintains motility and longevity of bovine sperm and enhances stable production of blastocysts in vitro.  

PubMed

The present study aimed to establish an efficient system for bovine embryo production by in vitro fertilization (IVF) that can achieve stable normal fertilization and blastocyst developmental rates in any bull without optimization of the sperm concentration in IVF medium. We examined the effects of a PHE mixture (20 ?M D-penicillamine, 10 ?M hypotaurine and 1 ?M epinephrine), theophylline (2.5 mM), and sperm concentration (1, 2 or 5 × 10(6) cells/ml) on fertilization and blastocyst developmental rates. High cleavage rates (78.3 to 92.4%) and blastocyst developmental rates (31.9 to 62.0%) at day 7 were obtained in the presence of PHE and theophylline in IVF medium with a sperm concentration of 2 × 10(6) cells/ml using sperm from 9 bulls. In addition, the synergistic effect of PHE and theophylline on normal fertilization (2 pronuclei) was clarified at 12 h after IVF with a sperm concentration of 1 × 10(6) cells/ml. Moreover, high linearity, high flagellar beat cross frequency, and low amplitude of lateral head of motile sperm were found by computer-assisted sperm analysis. In conclusion, the combination of the PHE mixture and theophylline synergistically accelerates sperm motility and sperm penetration of bovine oocytes. Theophylline activates sperm motility with increasing intracellular cAMP. However, PHE prevents an excessive increase of cAMP and maintains sperm motility without hyperactivation. When the combination of PHE and theophylline is added to IVF medium at a sperm concentration of 2 × 10(6) cells/ml, we can achieve stable normal fertilization and blastocyst development in any bull. PMID:25501343

Kang, Sung-Sik; Koyama, Keisuke; Huang, Weiping; Yang, Yinghua; Yanagawa, Yojiro; Takahashi, Yoshiyuki; Nagano, Masashi

2015-04-20

357

Ongoing twin pregnancy after vitrification of blastocysts produced by in-vitro matured oocytes retrieved from a woman with polycystic ovary syndrome  

Microsoft Academic Search

This case report describes an ongoing pregnancy after cryopreservation of blastocysts produced by in-vitro matured oocytes retrieved from a woman with polycystic ovary syndrome (PCOS). Oocyte retrieval was performed on day 18. The patient was administered 10 000 IU of hCG s.c. 36 h prior to oocyte collection. A total of 61 immature oocytes was obtained. Following incubation for 24-72

Weon-Young Son; San-Hyun Yoon; Sung-Jin Park; Hye-Jin Yoon; Won-Don Lee; Jin-Ho Lim

2002-01-01

358

Expression of ?4, ?v, ?1 and ?3 integrins during the implantation window on blastocyst of a mouse model of polycystic ovarian syndromes  

PubMed Central

Background: It has been hypothesized that blastocyst integrin expression changes can affect the spontaneous miscarriage in polycystic ovarian syndromes (PCOS). Objective: In this study, the profile of integrin genes and proteins was investigated on blastocyst of the PCOS experimental mouse model. Materials and Methods: 30 NMRI female mice were equally divided into 3 groups: control, experimental [PCOS that was injected estradiol valerate (40 mg/kg)]. After 8 weeks, each group was hyper stimulated by PMSG and HCG. Vaginal plaque was checked, and mice were investigated 5 days after the test. Progesterone and estradiol levels were determined; ?4, ?v, ?1 and ?3 integrin genes and protein of blastocysts were examined by real time PCR method and immunohistochemistry, respectively. Results: Estradiol level was significantly increased (p?0.035) in PCOS group. Based on our finding, the ratio of genes' expressions ?v, ?3, ?1 and ?4 in PCOS to control group was 0.479±0.01, 0.5±0.001, 2.7±0.4 and 1.023±0.2 respectively. Genes expression showed a great difference (p?0.001) between ?3, ?1 and ?v in PCOS compared to other groups. ?v and ?3 integrin proteins expressed in all groups but intensity of these proteins in PCOS groups, was lower than other groups. Conclusion: Pattern of ?v and ?3 integrins expression on the mouse blastocyst surface has an important effect during the implantation window. This pattern has changed in PCOS model and might have a great influence on implantation failure. Therefore, this experimental study suggests that a great attention to this problem may be essential in patients who are involved. PMID:25469135

Peyghambari, Fatemeh; Amanpour, Saeid; Fayazi, Mehri; Haddadi, Mahnaz; Muhammadnejad, Samad; Muhammadnejad, Ahad; Salimi, Mehdi; Mazaheri, Zohreh

2014-01-01

359

Mitochondrial DNA in Day 3 embryo culture medium is a novel, non-invasive biomarker of blastocyst potential and implantation outcome.  

PubMed

In assisted reproduction technology, embryo competence is routinely evaluated on morphological criteria. Over the last decade, efforts in improving non-invasive embryo assessment have looked into the secretome of embryos. Human embryos release genomic DNA (gDNA) and mitochondrial DNA (mtDNA) into the culture medium, and the mtDNA/gDNA ratio is significantly correlated with embryo fragmentation. Here, we investigate whether mtDNA/gDNA ratio in embryo spent medium is correlated with blastulation potential and implantation. The mtDNA/gDNA ratio was assessed in 699 Day 3 culture media by quantitative polymerase chain reaction (qPCR) to investigate its correlation with embryo morphology, blastocyst development and implantation. A logistic regression model evaluated whether mtDNA/gDNA ratio in the secretome may improve the prediction of blastulation. We found that embryos that successfully developed into blastocysts exhibited a significantly higher mtDNA/gDNA ratio in the culture medium compared with those that arrest (P = 0.0251), and mtDNA/gDNA, combined with morphological grading, has the potential to predict blastulation better than morphology alone (P = 0.02). Moreover, mtDNA/gDNA ratio was higher in the media from good-quality embryos that reached the full blastocyst stage on Day 5 compared with those that developed more slowly (P < 0.0001). With respect to blastocyst morphology, higher trophectoderm quality was associated with a higher mtDNA/gDNA ratio in the culture medium. Finally, a high mtDNA/gDNA ratio in spent medium was associated with successful implantation outcome (P = 0.0452) of good-quality embryos. In summary, the mtDNA/gDNA ratio in the Day 3 embryo secretome, in combination with morphological grading, may be a novel, non-invasive, early biomarker to improve identification of viable embryos with high developmental potential. PMID:25232043

Stigliani, S; Persico, L; Lagazio, C; Anserini, P; Venturini, P L; Scaruffi, P

2014-12-01

360

Self organisation and photoinduced charge transfer in single-wall carbon nanotubes embedded in a thermotropic liquid crystal polymer  

Microsoft Academic Search

A hybrid material composed by a thermotropic liquid crystal (LCP) polymer (HBA–PET) and single wall carbon nanotubes has been produced in order to study the interaction at the interface matrix\\/filler for possible applications in electronics and optics. The nanocomposites are characterized by a mosaic-like morphology, with regions of randomly placed LC fibers intercalated with regions formed by aligned polymer fibers,

Daniela Sordi; Silvia Orlanducci; Emanuela Tamburri; Daniele Passeri; Massimiliano Lucci; Maria Letizia Terranova

2011-01-01

361

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

362

Modified transfer matrix method model for a fiber Bragg grating strain sensor in polarization maintaining single mode optical fiber  

NASA Astrophysics Data System (ADS)

Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, EMI immunity, high sensitivity, and multiple multiplexing schemes, as compared to conventional electricity based strain sensors. FBG sensors written in Polarization Maintaining (PM) optical fiber offer an additional dimension of strain measurement simplifying sensor implementation within a structure. This simplification however, adds complexity to the detection of the sensor's optical response to its corresponding applied strain. We propose a modified Transfer Matrix Method model to simulate a fiber Bragg grating (FBG) in a polarization maintaining optical fiber. We study the effects of the reflected Bragg wavelength to the changes in shape of the optical fiber core waveguide and compare the results to the existing literature.

Quintana, Joel; Rumpf, Raymond; Gonzalez, Virgilio

2014-03-01

363

Enantioselective routes to both enantiomers of aryl alcohols with a single catalyst antipode: Ru and Os transfer hydrogenation catalysts.  

PubMed

[reaction--see text] The kinetic resolution of secondary aryl alcohols has been investigated. When (CyRuCl(2))(2), (1R,2S)-(+)-cis-1-amino-2-indanol, and KOH or (t)BuOK (catalyst 1) were combined in the presence of (+/-)-alcohols, ee's > 90% were generally observed. When applied to the kinetic resolution of (+/-)-indanol and (+/-)-tetralol, ee's = 99% (R) were observed. In addition, the asymmetric transfer hydrogenation of ketones was investigated with a catalyst, 2, generated in situ from (CyOsCl(2))(2), (1R,2S)-(+)-cis-1-amino-2-indanol, and (t)BuOK, yielding ee's of up to 98% (S). PMID:11700117

Faller, J W; Lavoie, A R

2001-11-15

364

Single-stage surgery combining nerve and tendon transfers for bilateral upper limb reconstruction in a tetraplegic patient: case report.  

PubMed

A 39-year-old tetraplegic patient had paralysis of elbow, thumb, and finger extension and thumb and finger flexion. We transferred axillary nerve branches to the triceps long and upper medial head motor branches, supinator motor branches to the posterior interosseous nerve, and brachioradialis tendon to the flexor pollicis longus and flexor superficialis of the index finger. Surgery was performed bilaterally 18 months after spinal cord injury. At 12 months after surgery, we performed bilateral distal radioulnar arthrodesis percutaneously. By 22 months postoperatively, we observed triceps strength scoring M3 bilaterally and full metacarpophalangeal joint extension scoring M4 bilaterally. The thumb span was 53 and 66 mm from the proximal index phalanx on the right and left sides, respectively. Pinch strength measured 1.5 kg on the left side and 2.0 kg on the right. Before surgery, the patient was incapable of grasping; after surgery, a useful grasp had been restored bilaterally. PMID:23751324

Bertelli, Jayme Augusto; Ghizoni, Marcos Flávio

2013-07-01

365

Microfluidic transfer of liquid interface for parallel stretching and stamping of terminal-unmodified single DNA molecules in zigzag-shaped microgrooves.  

PubMed

The molecular stretching of DNA is an indispensable tool for the optical exploration of base sequences and epigenomic changes of DNA at a single molecule level. In stretching terminal-unmodified DNA molecules parallel to each other on solid substrate, the receding meniscus assembly and capillary force through the dewetting process are quite useful. These can be achieved by pulling the substrate out of the DNA solution or sliding a droplet of DNA solution between a pair of substrates. However, currently used methods do not allow control over liquid interface motion and single-molecule DNA positioning. Here, we show a microfluidic device for stretching DNA molecules by syringing through microgrooves. The device can trap single DNA molecules at vertices of the microgrooves, which were designed as parallel zigzag lines. Different zigzag pattern depths, sizes, and shapes were studied to evaluate the adsorption possibility of DNA on the surface. The microfluidic transfer of the liquid interface stretched over 1500 DNA molecules simultaneously. The stretched DNA molecules could be stamped to a silanized surface. The device will therefore serve as a template preparation for high-resolution DNA imaging studies. PMID:25318047

Yasaki, Hirotoshi; Onoshima, Daisuke; Yasui, Takao; Yukawa, Hiroshi; Kaji, Noritada; Baba, Yoshinobu

2015-01-01

366

Long-range protein electron transfer observed at the single-molecule level: In situ mapping of redox-gated tunneling resonance  

PubMed Central

A biomimetic long-range electron transfer (ET) system consisting of the blue copper protein azurin, a tunneling barrier bridge, and a gold single-crystal electrode was designed on the basis of molecular wiring self-assembly principles. This system is sufficiently stable and sensitive in a quasi-biological environment, suitable for detailed observations of long-range protein interfacial ET at the nanoscale and single-molecule levels. Because azurin is located at clearly identifiable fixed sites in well controlled orientation, the ET configuration parallels biological ET. The ET is nonadiabatic, and the rate constants display tunneling features with distance-decay factors of 0.83 and 0.91 Å–1 in H2O and D2O, respectively. Redox-gated tunneling resonance is observed in situ at the single-molecule level by using electrochemical scanning tunneling microscopy, exhibiting an asymmetric dependence on the redox potential. Maximum resonance appears around the equilibrium redox potential of azurin with an on/off current ratio of ?9. Simulation analyses, based on a two-step interfacial ET model for the scanning tunneling microscopy redox process, were performed and provide quantitative information for rational understanding of the ET mechanism. PMID:16260751

Chi, Qijin; Farver, Ole; Ulstrup, Jens

2005-01-01

367

Hydrogen peroxide elimination from C4a-hydroperoxyflavin in a flavoprotein oxidase occurs through a single proton transfer from flavin N5 to a peroxide leaving group.  

PubMed

C4a-hydroperoxyflavin is found commonly in the reactions of flavin-dependent monooxygenases, in which it plays a key role as an intermediate that incorporates an oxygen atom into substrates. Only recently has evidence for its involvement in the reactions of flavoprotein oxidases been reported. Previous studies of pyranose 2-oxidase (P2O), an enzyme catalyzing the oxidation of pyranoses using oxygen as an electron acceptor to generate oxidized sugars and hydrogen peroxide (H(2)O(2)), have shown that C4a-hydroperoxyflavin forms in P2O reactions before it eliminates H(2)O(2) as a product (Sucharitakul, J., Prongjit, M., Haltrich, D., and Chaiyen, P. (2008) Biochemistry 47, 8485-8490). In this report, the solvent kinetic isotope effects (SKIE) on the reaction of reduced P2O with oxygen were investigated using transient kinetics. Our results showed that D(2)O has a negligible effect on the formation of C4a-hydroperoxyflavin. The ensuing step of H(2)O(2) elimination from C4a-hydroperoxyflavin was shown to be modulated by an SKIE of 2.8 ± 0.2, and a proton inventory analysis of this step indicates a linear plot. These data suggest that a single-proton transfer process causes SKIE at the H(2)O(2) elimination step. Double and single mixing stopped-flow experiments performed in H(2)O buffer revealed that reduced flavin specifically labeled with deuterium at the flavin N5 position generated kinetic isotope effects similar to those found with experiments performed with the enzyme pre-equilibrated in D(2)O buffer. This suggests that the proton at the flavin N5 position is responsible for the SKIE and is the proton-in-flight that is transferred during the transition state. The mechanism of H(2)O(2) elimination from C4a-hydroperoxyflavin is consistent with a single proton transfer from the flavin N5 to the peroxide leaving group, possibly via the formation of an intramolecular hydrogen bridge. PMID:21454569

Sucharitakul, Jeerus; Wongnate, Thanyaporn; Chaiyen, Pimchai

2011-05-13

368

A single-phased tunable emission phosphor MgY2Si3O10: Eu(3+), Bi(3+) with efficient energy transfer for white LEDs.  

PubMed

A novel single-phased tunable emitting phosphor MgY2Si3O10: Bi(3+), Eu(3+) has been synthesized by a conventional high temperature solid-state method. X-ray diffraction (XRD), photoluminescence emission and excitation spectra were utilized to characterize the as-synthesized samples. Under UV-light pumping, MgY2Si3O10: Bi(3+) showed characteristic blue emission corresponding to the (3)P1?(1)S0 transition of Bi(3+) ions, and MgY2Si3O10: Eu(3+) showed characteristic red emission corresponding to the (5)D0?(7)FJ (J = 1, 2, 3, 4) transition of Eu(3+) ions. Spectra indicate that Bi(3+) ions occupy two nonequivalent sites in the MgY2Si3O10 matrix, namely, Bi(3+)(i) and Bi(3+)(ii). The two sites (Bi(3+)(i) and Bi(3+)(ii)) exhibit broad emission peaks at 411 nm and 490 nm, respectively. Efficient energy transfer between these two Bi(3+) sites has been proven using the spectra. The spectral overlap between the emission spectrum of Bi(3+) and the excitation spectrum of Eu(3+) allows for resonance-type energy transfer to occur from Bi(3+) to Eu(3+). The efficient energy transfer from Bi(3+) to Eu(3+)via a dipole-quadrupole interaction mechanism is significantly demonstrated by comparing experimental data with theoretical calculations. According to the concentration quenching-method, the critical distance of energy transfer from Bi(3+) to Eu(3+) is calculated to be 13.2 Å. As it is a new phosphor, CIE coordinates and CCT temperature, in addition to efficient energy transfer have been also investigated in detail. White light emission for MgY2Si3O10: n Bi(3+), m Eu(3+) can be realized through controlling the concentrations of Bi(3+) and Eu(3+). All of the results indicate that MgY2Si3O10: n Bi(3+), m Eu(3+) is a potential phosphor for white light UV-LEDs. PMID:25409734

Zhou, Hongpeng; Jin, Ye; Jiang, Mingsong; Wang, Qingping; Jiang, Xingxing

2015-01-21

369

PDGF signaling is required for primitive endoderm cell survival in the inner cell mass of the mouse blastocyst  

PubMed Central

At the end of the preimplantation period, the inner cell mass (ICM) of the mouse blastocyst is composed of two distinct cell lineages, the pluripotent epiblast (EPI) and the primitive endoderm (PrE). The current model for their formation involves initial co-expression of lineage-specific markers followed by mutual-exclusive expression resulting in a salt-and-pepper distribution of lineage precursors within the ICM. Subsequent to lineage commitment, cell rearrangements and selective apoptosis are thought to be key processes driving and refining the emergence of two spatially distinct compartments. Here, we have addressed a role for PDGF signaling in the regulation of programmed cell death during early mouse embryonic development. By combining genetic and pharmacological approaches, we demonstrate that embryos lacking PDGF activity exhibited caspase-dependent selective apoptosis of PrE cells. Modulating PDGF activity did not affect lineage commitment or cell sorting, suggesting that PDGF is involved in the fine-tuning of patterning information. Our results also indicate that PDGF and FGF tyrosine kinase receptors exert distinct and non-overlapping functions in PrE formation. Taken together, these data uncover an early role of PDGF signaling in PrE cell survival at the time when PrE and EPI cells are segregated. PMID:23733391

Artus, Jérôme; Kang, Minjung; Cohen-Tannoudji, Michel; Hadjantonakis, Anna-Katerina

2014-01-01

370

Supplementation of sperm cryopreservation media with cell permeable superoxide dismutase mimetic agent (MnTE) improves goat blastocyst formation.  

PubMed

The aim of this study was to assess whether a cell permeable superoxide dismutase agent such as MnTE, can further improve the quality of frozen/thawed semen sample using a commercially optimized sperm cryopreservation media (Bioxcell). Bioxcell was supplemented with different concentration of MnTE. Sperm membrane integrity, motility, viability and acrosomal status were assessed after freezing. Optimized concentration of MnTE was defined and used to assess fertilization and developmental potential. 0.1 ?M MnTE significantly improved membrane integrity while 0.01 ?M MnTE significantly improved acrosomal integrity post thawing. Addition of 0.01 ?M MnTE also improved blastocyst formation rate. Supplementation of commercially optimized cryopreservation media with MnTE further improves the quality of goat frozen semen sample and may have important consequence of future embryo development. This effect may be attributed to cell permeable behavior of this antioxidant which may protect sperm genome from ROS-induced DNA damage. PMID:23981864

Forouzanfar, Mohsen; Abid, Abdolah; Hosseini, Sayyed Morteza; Hajian, Mehdi; Nasr Esfahani, Mohammad Hossein

2013-12-01

371

Tracer Tests in a Fractured Dolomite: 3. Analysis of Mass Transfer in Single-Well Injection-Withdrawal Tests  

SciTech Connect

We investigated multiple-rate diffusion as a possible explanation for observed behavior in a suite of single-well injection-withdrawal (SWIW) tests conducted in a fractured dolomite. We first investigated the ability of a conventional double-porosity model and a multirate diffusion model to explain the data. This revealed that the multirate diffusion hypothesis/model is most consistent with all available data, and is the only model to date that is capable of matching each of the recovery curves entirely. Second, we studied the sensitivity of the SWIW recovery curves to the distribution of diffusion rate coefficients and other parameters. We concluded that the SWIW test is very sensitive to the distribution of rate coefficients, but is relatively insensitive to other flow and transport parameters such as advective porosity and dispersivity. Third, we examined the significance of the constant double-log late-time slopes ({minus}2. 1 to {minus}2.8), which are present in several data sets. The observed late-time slopes are significantly different than would be predicted by either conventional double-porosity or single-porosity media, and are found to be a distinctive feature of multirate diffusion under SWIW test conditions. Fourth, we found that the estimated distributions of diffusion rate coefficients are very broad, with the distributions spanning a range of at least 3.6 to 5.7 orders of magnitude.

Haggerty, R.; Fleming, S.W.; Meigs, L.C.; McKenna, S.A.

1999-03-04

372

Synthesis, transfer printing, electrical and optical properties, and applications of materials composed of self-assembled, aligned single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Super growth of single-walled carbon nanotubes (SWNTs) has emerged as a unique method for synthesizing self-assembled, pristine, aligned SWNT materials composed of ultra-long (millimeter-long) nanotubes. This thesis focuses on novel routes of synthesizing such self-assembled SWNTs and the challenges that arise in integrating this material into next-generation applications. First of all, this work provides unique insight into growth termination of aligned SWNTs, emphasizing the mechanism that inhibits the growth of infinitely long nanotubes. Exhaustive real-time growth studies, combined with ex-situ and in-situ TEM characterization emphasizes that Ostwald ripening and subsurface diffusion of catalyst particles play a key role in growth termination. As a result, rational steps to solving this problem can enhance growth, and may ultimately lead to the meter or kilometer-long SWNTs that are necessary for a number of applications. In addition, other novel synthesis routes are discussed, such as the ability to form macroscopic fibrils of SWNTs, called "flying carpets" from 40 nm thick substrates, and the ability to achieve supergrowth of SWNTs that are controllably doped with nitrogen. In the latter case, molecular heterojunctions of doped and undoped sections in a single strand of ultralong SWNTs are demonstrated Secondly, as supergrowth is conducted on alumina coated SiO2 substrates, any applications will require that one can transfer the SWNTs to host surfaces with minimal processing. This work demonstrates a unique contact transfer route by which both patterned arrays of SWNTs, or homogenous SWNT carpets, can be transferred to any host surface. In the first case, the SWNTs are grown vertically aligned, and transferred in patterns of horizontally aligned SWNT. This transfer process relies on simple water-vapor etching of amorphous carbons at the catalyst following growth, and strong van der Waals adhesion of the high surface-area SWNT to host surfaces (gecko effect). Next, as the SWNTs produced in supergrowth are notably large in diameter (2-5 nm), this work provides the first characterization of these SWNTs using combined microscopy and infrared polarized absorption studies. Perfectly aligned SWNTs are transferred to infrared optical windows and mounted in a rotatable vacuum cell in which polarization dependent characterization is carried out. By modeling features observed in absorption to expected optical excitonic transition energies, diameter distributions are rapidly extracted. In addition, other concepts of optical characterization in ultra-long aligned SWNTs are explored. For example, the concept of using polarized near-IR characterization for such SWNT samples is inadequate to characterize the bulk alignment due to the mismatch of the excitation wavelength and the SWNT length. Therefore, comparing anisotropy in polarized near-IR Raman or absorption gives substantially different results than anisotropic electrical transport measurements. In addition to optical characterization, this work uniquely finds that the electrical transport properties of SWNTs is ultimately limited by SWNT-SWNT junctions. This is evident in temperature-dependent DC and AC conductivity measurements that emphasize localization-induced transport characteristics. A number of non-classical electrical transport features are observed that can simply be related to the sensitivity of electrical transport to SWNT-SWNT junctions. This means that despite the incredible electrical properties of individual SWNTs, it is necessary to focus on the growth and processing of ultra-long SWNTs in order to realistically make nanotube-based materials comparable in transport characteristics to conventional materials. Finally, this work concludes by demonstrating progress on the fabrication of new SWNT-based applications. First of all, a new type of solid-state supercapacitor material is fabricated where vertically aligned SWNT are coated with metal-oxide dielectric and counterelectrode layers to form efficient supercapacitors. This design benefits from the

Pint, Cary L.

373

Effects of grade of oocyte-cumulus complex and the interactions between grades on the production of blastocysts in the cow, ewe and lamb.  

PubMed

There is an association between the size of the cumulus investment and the in vitro developmental ability of the oocyte-cumulus complex (OCC) that provides a basis for the selection of OCCs. However, the value of selection is confounded by humoral interactions between OCCs that influence the development of OCCs of other grade(s). This study examined the effect of size of the cumulus investment (OCC grade) and the interactions between grades on the developmental ability of oocytes collected from the cow, ewe and lamb. OCCs were classified into A, B and C grades on visual assessment of the number of cumulus cell layers or left unselected (Unselected). In the cow, there were 669 +/- 228 to 4763 +/- 228 cells per OCC whereas comparable figures in the ewe and lamb were 593 +/- 252 to 3716 +/- 252 and 366 +/- 228 to 3263 +/- 228 respectively (A > Unselected > B > C; Experiment 1). In Experiment 2, OCCs were made to mature within grade and the efficiency of blastocyst production and blastocyst quality was compared with that obtained in the Unselected group. Grade was associated with significant (p < 0.05) differences in cleavage rate, blastocyst production rate and the mean number of nuclei per embryo (generally A > B > C across animal types). However, the performance of A grade OCCs in the cow and lamb did not differ significantly from that obtained in the Unselected group whereas in the ewe, A grade OCCs were significantly (p < 0.05) better. Furthermore, the performance of the Unselected group was significantly (p < 0.05) better than that of the combined grades (A + B + C) in the cow but there were no differences in either the ewe or lamb. It is concluded that (i) interactions between OCCs of different grade influence the developmental ability of OCCs in the cow and, to a lesser extent, the lamb, (ii) selection of OCCs in the cow and lamb would lead to the exclusion of many OCCs that have the ability to develop into blastocysts and (iii) selection in the ewe would improve the efficiency of blastocyst production although its value is limited by the low percentage of A grade OCCs. PMID:17976063

Kelly, J M; Kleemann, D O; Rudiger, S R; Walker, S K

2007-12-01

374

Rapid charge-transfer in polypyrrole-single wall carbon nanotube complex counter electrodes: Improved photovoltaic performances of dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, high efficiency, good durability, and easy fabrication. However, enhancement of power conversion efficiency and high cost of Pt counter electrode are still significant issues in commercial application of DSSCs. Herein, pyrrole-single wall nanotube (pyrrole-SWCNT) complexes are pioneerly synthesized by a reflux technique and subsequently in-situ polymerized and employed as counter electrodes (CEs) for DSSCs. Different from traditional polypyrrole/SWCNT (PPy/SWCNT) composites, the resultant PPy-SWCNT complexes are expected to fulfill the good electrical-conduction of SWCNT and electrocatalytic behaviors of PPy in accelerating electrochemical activity and charge transfer owing to the covalent bond between PPy (N atoms) and SWCNT (C atoms). The DSSCs employing PPy-SWCNT complex CEs exhibit significantly enhanced photovoltaic performances, in which a promising power conversion efficiency of 8.30% is obtained from PPy-2 wt‰ SWCNT complex CE in comparison with 6.31% from PPy-only CE. The high conversion efficiency, rapid charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PPy-SWCNT complexes in robust DSSCs.

He, Benlin; Tang, Qunwei; Luo, Jinghuan; Li, Qinghua; Chen, Xiaoxu; Cai, Hongyuan

2014-06-01

375

A single-component white-emitting CaSr2Al2O6:Ce3+, Li+, Mn2+ phosphor via energy transfer.  

PubMed

A series of single-component Ce(3+), Li(+), Mn(2+) ions codoped color-tunable CaSr2Al2O6 phosphors were synthesized by a high-temperature solid-state reaction, and the photoluminescence properties as well as the energy transfer mechanism from Ce(3+) to Mn(2+) ions have been investigated in detail. The Ce(3+) activated phosphors have strong absorption in the range of 250-420 nm and can give a blue emission centered at about 460 nm. When Mn(2+) ions are codoped, the emission of CaSr2Al2O6:Ce(3+), Li(+), Mn(2+) phosphors can be tuned from blue to red through adjusting the doping concentration of the Mn(2+) ions, under the irradiation of 358 nm. When the concentration of Mn(2+) is increased to 0.02, a warm-white light can be obtained with good CIE coordinates of (0.388, 0.323) and a low CCT of 3284 K. The energy transfer mechanism from the Ce(3+) to Mn(2+) ions is demonstrated to be a quadrupole-quadrupole interaction based on the analysis of the decay curves of the phosphors. The thermal quenching stability was also investigated. The results indicate that CaSr2Al2O6:Ce(3+), Li(+), Mn(2+) samples might have potential applications in w-LEDs. PMID:24968122

Li, Yanyan; Shi, Yurong; Zhu, Ge; Wu, Quansheng; Li, Hao; Wang, Xicheng; Wang, Qian; Wang, Yuhua

2014-07-21

376

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

377

Somatic cell nuclear transfer and derivation of embryonic stem cells in the mouse.  

PubMed

Addressing the fundamental questions of nuclear equivalence in somatic cells has fascinated scientists for decades and has resulted in the development of somatic cell nuclear transfer (SCNT) or animal cloning. SCNT involves the transfer of the nucleus of a somatic cell into the cytoplasm of an egg whose own chromosomes have been removed. In the mouse, SCNT has not only been successfully used to address the issue of nuclear equivalence, but has been used as a model system to test the hypothesis that embryonic stem cells (ESCs) derived from NT blastocysts have the potential to correct--through genetic manipulations--degenerative diseases. This paper aims to provide a comprehensive description of SCNT in the mouse and the derivation of ESCs from blastocysts generated by this technique. SCNT is a very challenging and inefficient procedure because it is technically complex, it bypasses the normal events of gamete interactions and egg activation, and it depends on adequate reprogramming of the somatic cell nucleus in vivo. Improvements in any or all those aspects may enhance the efficiency and applicability of SCNT. ESC derivation from SCNT blastocysts, on the other hand, requires the survival of only a few successfully reprogrammed cells, which have the capacity to proliferate indefinitely in vitro, maintain correct genetic and epigenetic status, and differentiate into any cell type in the body--characteristics that are essential for transplantation therapy or any other in vivo application. PMID:18593608

Markoulaki, Styliani; Meissner, Alexander; Jaenisch, Rudolf

2008-06-01

378

Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area  

SciTech Connect

Single-well injection-withdrawal (SWIW) tracer tests involve injection of traced fluid and subsequent tracer recovery from the same well, usually with some quiescent time between the injection and withdrawal periods. SWIW are insensitive to variations in advective processes that arise from formation heterogeneities, because upon withdrawal, fluid parcels tend to retrace the paths taken during injection. However, SWIW are sensitive to diffusive processes, such as diffusive exchange of conservative or reactive solutes between fractures and rock matrix. This paper focuses on SWIW tests in which temperature itself is used as a tracer. Numerical simulations demonstrate the sensitivity of temperature returns to fracture-matrix interaction. We consider thermal SWIW response to the two primary reservoir improvements targeted with stimulation, (1) making additional fractures accessible to injected fluids, and (2) increasing the aperture and permeability of pre-existing fractures. It is found that temperature returns in SWIW tests are insensitive to (2), while providing a strong signal of more rapid temperature recovery during the withdrawal phase for (1).

Pruess, K.; Doughty, C.

2010-01-15

379

Single-Step Synthesis of Al-Doped TiO2 Nanoparticles Using Non-Transferred Thermal Plasma Torch  

NASA Astrophysics Data System (ADS)

Al-doped TiO2 nanoparticles possessing visible-light photocatalytic activity were fabricated with an atmospheric-pressure thermal plasma system via a single-step direct combination of vaporized Ti, Al, and O2. Pure Ti and Al2O3 powders and ultrahigh-purity O2 were used as the precursors. The experimental results showed that the size of synthesized TiO2 was between 10 and 105 nm. Nevertheless, the nanoparticles with sizes smaller than 50 nm accounted for approximately 80% of the total number. The observed size reduction appeared to be the suppression on particle growth due to the introduction of Al species into TiO2 crystal. The largest specific surface area of the Al-doped TiO2 was 44 m2·g-1. The anatase phase was noticeably decreased with increasing the Al2O3 addition. The absorption spectra of Al-doped TiO2 shifted from UV to visible-light region with respect to an increase in Al2O3 addition. Oxygen in the formed TiO2 was found to be in TiO2 crystal lattice and in surface hydroxyl groups. Both Ti4+ and Ti3+ existed in the formed TiO2. However, the Ti3+ amount significantly increased with increasing Al2O3 addition due to Al/Ti substitution and the resulted oxygen vacancy.

Tsai, Cheng-Yen; Hsi, Hsing-Cheng; Bai, Hsunling; Fan, Kuo-Shuh; Sun, Hung-Dar

2012-01-01

380

Expression of LIF, VEGF, CD57 and CD68 after the transfer of rat embryos to mouse uteri  

Microsoft Academic Search

The high failure rate of interspecific pregnancy is a major obstacle to the successful interspecific cloning of mammals. To\\u000a investigate the reasons for the failure of interspecfic pregnancy between rats and mice, we transferred rat blastocysts into\\u000a mouse uteri on the third day of pseudopregnancy (D3). Our previous study showed that intact rat embryos could still be observed\\u000a in mouse

Bojie Dai; Yujing Cao; Xichao Wang; Jiaxi Zhou; Jian Zhang; Dayuan Chen; Enkui Duan

2003-01-01

381

Application of modern tests for stationarity to single-trial MEG data: transferring powerful statistical tools from econometrics to neuroscience.  

PubMed

Stationarity is a crucial yet rarely questioned assumption in the analysis of time series of magneto- (MEG) or electroencephalography (EEG). One key drawback of the commonly used tests for stationarity of encephalographic time series is the fact that conclusions on stationarity are only indirectly inferred either from the Gaussianity (e.g. the Shapiro-Wilk test or Kolmogorov-Smirnov test) or the randomness of the time series and the absence of trend using very simple time-series models (e.g. the sign and trend tests by Bendat and Piersol). We present a novel approach to the analysis of the stationarity of MEG and EEG time series by applying modern statistical methods which were specifically developed in econometrics to verify the hypothesis that a time series is stationary. We report our findings of the application of three different tests of stationarity--the Kwiatkowski-Phillips-Schmidt-Schin (KPSS) test for trend or mean stationarity, the Phillips-Perron (PP) test for the presence of a unit root and the White test for homoscedasticity--on an illustrative set of MEG data. For five stimulation sessions, we found already for short epochs of duration of 250 and 500 ms that, although the majority of the studied epochs of single MEG trials were usually mean-stationary (KPSS test and PP test), they were classified as nonstationary due to their heteroscedasticity (White test). We also observed that the presence of external auditory stimulation did not significantly affect the findings regarding the stationarity of the data. We conclude that the combination of these tests allows a refined analysis of the stationarity of MEG and EEG time series. PMID:22095173

Kipi?ski, Lech; König, Reinhard; Sielu?ycki, Cezary; Kordecki, Wojciech

2011-10-01

382

Vitamin C induces Tet-dependent DNA demethylation in ESCs to promote a blastocyst-like state  

PubMed Central

DNA methylation is a heritable epigenetic modification involved in gene silencing, imprinting, and the suppression of retrotransposons1. Global DNA demethylation occurs in the early embryo and the germline2,3 and may be mediated by Tet (ten-eleven-translocation) enzymes4–6, which convert 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC)7. Tet enzymes have been extensively studied in mouse embryonic stem cells (ESCs)8–12, which are generally cultured in the absence of Vitamin C (VitC), a potential co-factor for Fe(II) 2-oxoglutarate dioxygenase enzymes like Tets. Here we report that addition of VitC to ESCs promotes Tet activity leading to a rapid and global increase in hmC. This is followed by DNA demethylation of numerous gene promoters and up-regulation of demethylated germline genes. Tet1 binding is enriched near the transcription start site (TSS) of genes affected by VitC treatment. Importantly, VitC, but not other antioxidants, enhances the activity of recombinant Tet1 in a biochemical assay and the VitC-induced changes in hmC and mC are entirely suppressed in Tet1/2 double knockout (Tet DKO) ESCs. VitC has the strongest effects on regions that gain methylation in cultured ESCs compared to blastocysts and in vivo are methylated only after implantation. In contrast, imprinted regions and intracisternal A-particle (IAP) retroelements, which are resistant to demethylation in the early embryo2,13, are resistant to VitC-induced DNA demethylation. Collectively, this study establishes VitC as a direct regulator of Tet activity and DNA methylation fidelity in ESCs. PMID:23812591

Blaschke, Kathryn; Ebata, Kevin T.; Karimi, Mohammad M.; Zepeda-Martínez, Jorge A.; Goyal, Preeti; Mahapatra, Sahasransu; Tam, Angela; Laird, Diana J.; Hirst, Martin; Rao, Anjana; Lorincz, Matthew C.; Ramalho-Santos, Miguel

2013-01-01

383

Reversal of Hyperglycemia by Insulin-Secreting Rat Bone Marrow- and Blastocyst-Derived Hypoblast Stem Cell-Like Cells  

PubMed Central

?-cell replacement may efficiently cure type 1 diabetic (T1D) patients whose insulin-secreting ?-cells have been selectively destroyed by autoantigen-reactive T cells. To generate insulin-secreting cells we used two cell sources: rat multipotent adult progenitor cells (rMAPC) and the highly similar rat extra-embryonic endoderm precursor (rXEN-P) cells isolated under rMAPC conditions from blastocysts (rHypoSC). rMAPC/rHypoSC were sequentially committed to definitive endoderm, pancreatic endoderm, and ?-cell like cells. On day 21, 20% of rMAPC/rHypoSC progeny expressed Pdx1 and C-peptide. rMAPCr/HypoSC progeny secreted C-peptide under the stimulus of insulin agonist carbachol, and was inhibited by the L-type voltage-dependent calcium channel blocker nifedipine. When rMAPC or rHypoSC differentiated d21 progeny were grafted under the kidney capsule of streptozotocin-induced diabetic nude mice, hyperglycemia reversed after 4 weeks in 6/10 rMAPC- and 5/10 rHypoSC-transplanted mice. Hyperglycemia recurred within 24 hours of graft removal and the histological analysis of the retrieved grafts revealed presence of Pdx1-, Nkx6.1- and C-peptide-positive cells. The ability of both rMAPC and HypoSC to differentiate to functional ?-cell like cells may serve to gain insight into signals that govern ?-cell differentiation and aid in developing culture systems to commit other (pluripotent) stem cells to clinically useful ?-cells for cell therapy of T1D. PMID:23671681

Kumar, Anujith; Lo Nigro, Antonio; Gysemans, Conny; Cai, Qing; Esguerra, Camila; Nelson-Holte, Molly; Heremans, Yves; Jiménez-González, María; Porciuncula, Angelo; Mathieu, Chantal; Binas, Bert; Heimberg, Harry; Prosper, Felipe; Hering, Bernhard; Verfaillie, Catherine M.; Barajas, Miguel

2013-01-01

384

Reversal of hyperglycemia by insulin-secreting rat bone marrow- and blastocyst-derived hypoblast stem cell-like cells.  

PubMed

?-cell replacement may efficiently cure type 1 diabetic (T1D) patients whose insulin-secreting ?-cells have been selectively destroyed by autoantigen-reactive T cells. To generate insulin-secreting cells we used two cell sources: rat multipotent adult progenitor cells (rMAPC) and the highly similar rat extra-embryonic endoderm precursor (rXEN-P) cells isolated under rMAPC conditions from blastocysts (rHypoSC). rMAPC/rHypoSC were sequentially committed to definitive endoderm, pancreatic endoderm, and ?-cell like cells. On day 21, 20% of rMAPC/rHypoSC progeny expressed Pdx1 and C-peptide. rMAPCr/HypoSC progeny secreted C-peptide under the stimulus of insulin agonist carbachol, and was inhibited by the L-type voltage-dependent calcium channel blocker nifedipine. When rMAPC or rHypoSC differentiated d21 progeny were grafted under the kidney capsule of streptozotocin-induced diabetic nude mice, hyperglycemia reversed after 4 weeks in 6/10 rMAPC- and 5/10 rHypoSC-transplanted mice. Hyperglycemia recurred within 24 hours of graft removal and the histological analysis of the retrieved grafts revealed presence of Pdx1-, Nkx6.1- and C-peptide-positive cells. The ability of both rMAPC and HypoSC to differentiate to functional ?-cell like cells may serve to gain insight into signals that govern ?-cell differentiation and aid in developing culture systems to commit other (pluripotent) stem cells to clinically useful ?-cells for cell therapy of T1D. PMID:23671681

Kumar, Anujith; Lo Nigro, Antonio; Gysemans, Conny; Cai, Qing; Esguerra, Camila; Nelson-Holte, Molly; Heremans, Yves; Jiménez-González, María; Porciuncula, Angelo; Mathieu, Chantal; Binas, Bert; Heimberg, Harry; Prosper, Felipe; Hering, Bernhard; Verfaillie, Catherine M; Barajas, Miguel

2013-01-01

385

Set up of a serum-free culture system for bovine embryos: embryo development and quality before and after transient transfer.  

PubMed

It is well known that serum in culture medium negatively affects blastocyst quality. The objective of this work was to develop and test a serum-free culture medium which could improve embryo quality, measured by the resistance to freezing, lipid and glutathione content of the resulting blastocysts, as well as the ability of the blastocysts to elongate after transient transfer to recipient cows. In a first experiment we showed that adding a mixture of insulin, transferrin and selenium to serum-free Synthetic Oviduct Fluid medium (SOF-ITS) improved embryo development and quality. In the second experiment, the addition of BSA to SOF-ITS further improved blastocyst development. Moreover, a reduction in lipid content of morulae was observed in SOF-ITS-BSA by comparison with morulae cultured with serum (SOF-FCS). The resistance to freezing measured by hatching rates 24h post-thawing was also improved for blastocysts with a diameter between 160 and 180 microm cultured in SOF-ITS-BSA by comparison to those produced with serum. In order to evaluate the redox potential of the embryos, reduced glutathione content (GSH) was evaluated both before and after cryopreservation. A significant decrease in glutathione was observed after freezing, whatever the culture medium, but no difference was observed between culture conditions. Transient transfers were performed and elongated D-13 embryos were recovered. Elongation was more pronounced and the embryonic disk more often visible in embryos cultured in SOF-ITS-BSA than in embryos cultured with FCS. In conclusion, the serum-free system we developed to produce in vitro bovine embryos meets the developmental and qualitative requirements for a large-scale use. PMID:18242668

George, F; Daniaux, C; Genicot, G; Verhaeghe, B; Lambert, P; Donnay, I

2008-03-15

386

On the sensitivity of long-term magnetotelluric monitoring in Southern Italy and source-dependent robust single station transfer function variability  

NASA Astrophysics Data System (ADS)

Since 2007, a permanent magnetotelluric (MT) monitoring station has been working in the seismic area of the Agri Valley (Basilicata region, southern Italy) in order to investigate the stability of the MT transfer function. The station was installed in a rural area near the supposed seismogenic fault of the strong earthquake (Mw = 6.9) that struck the Agri Valley in 1857. Analysing about 4 yr of MT data characterized by a low seismic activity, the long-term systematic variations of robust single station MT transfer function estimates were observed in two different sounding period ranges. First, a significant seasonal component of variability for short periods was noted; these short periods were up to 16 s and were linked to variations in wetting/drying of soil moisture in the shallower layers. Second, a connection between the monitored estimates and global geomagnetic activity, Ap index, was found, particularly in the [20-100 s] period range. Analysing remote reference results and tipper estimates in shorter monitoring window, it was shown that such effect cannot be explained by a local or incoherent noise, and a large-scale coherent source should be claimed. We show that this effect is subtle because it produces smooth estimates, satisfying the dispersion relationship between apparent resistivity and phase, with small error bars. As the global geomagnetic activity level increases, robust estimators, like the median value, can be considered as a representative of the estimates due to the natural source, and they tend to stabilize when the Ap index approaches 10. It is also worth noting that our monitored time window includes the recent global minimum of solar activity which occurred in 2009, thus enhancing the estimate dependence on the Ap index.

Romano, Gerardo; Balasco, Marianna; Lapenna, Vincenzo; Siniscalchi, Agata; Telesca, Luciano; Tripaldi, Simona

2014-06-01

387

Multi-transgenic pigs expressing three fluorescent proteins produced with high efficiency by sperm mediated gene transfer.  

PubMed

Multi-gene transgenic pigs would be of benefit for large animal models in medical, agricultural, and pharmaceutical applications; in particular for xenotransplantation, where extensive genetic manipulation of donor pigs is required to make them suitable for organ grafting to humans. We used the sperm mediated gene transfer (SMGT) method to produce with high efficiency multi-gene transgenic pigs using three genes coding for fluorescent proteins: enhanced blue (EBFP), green (EGFP), and red (DsRed2). All three fluorescent proteins were expressed in 171 out of 195 normally developed morula/blastocysts examined at day 6 post insemination (88%). Genomic DNA of 18 piglets born from two litters was screened by PCR, showing that all piglets were transgenic with at least one gene, 7/18 piglets were triple transgenic, 7/18 double transgenic, and 4/18 single transgenic. Fluorescence in situ hybridization (FISH) analysis revealed multiple sites of integration of the transgenes. RNA and protein expression was found in muscle, heart, liver, hair, and peripheral blood mononuclear cells (PBMCs). These results show that SMGT is an effective method for introducing multiple genes into pigs as shown by the simultaneous expression of three fluorescent proteins. PMID:15906394

Webster, Nicole L; Forni, Monica; Bacci, Maria Laura; Giovannoni, Roberto; Razzini, Riccardo; Fantinati, Paolo; Zannoni, Augusta; Fusetti, Lisa; Dalprà, Leda; Bianco, Maria Rosaria; Papa, Michele; Seren, Eraldo; Sandrin, Mauro S; Mc Kenzie, Ian F C; Lavitrano, Marialuisa

2005-09-01

388

Citrinin induces apoptosis via a mitochondria-dependent pathway and inhibition of survival signals in embryonic stem cells, and causes developmental injury in blastocysts  

PubMed Central

The mycotoxin CTN (citrinin), a natural contaminant in foodstuffs and animal feeds, has cytotoxic and genotoxic effects on various mammalian cells. CTN is known to cause cell injury, including apoptosis, but the precise regulatory mechanisms of CTN action, particularly in stem cells and embryos, are currently unclear. In the present paper, I report that CTN has cytotoxic effects on mouse embryonic stem cells and blastocysts, and is associated with defects in their subsequent development, both in vitro and in vivo. Experiments in embryonic stem cells (ESC-B5) showed that CTN induces apoptosis via ROS (reactive oxygen species) generation, increased Bax/Bcl-2 ratio, loss of MMP (mitochondrial membrane potential), induction of cytochrome c release, and activation of caspase 3. In this model, CTN triggers cell death via inactivation of the HSP90 [a 90 kDa isoform of the HSP (heat-shock protein) family proteins]/multichaperone complex and subsequent degradation of Ras and Raf-1, further inhibiting anti-apoptotic processes, such as the Ras?ERK (extracellular-signal-regulated kinase) signal transduction pathway. In addition, CTN causes early developmental injury in mouse ESCs and blastocysts in vitro. Lastly, using an in vivo mouse model, I show that consumption of drinking water containing 10 ?M CTN results in blastocyst apoptosis and early embryonic developmental injury. Collectively, these findings show for the first time that CTN induces ROS and mitochondria-dependent apoptotic processes, inhibits Ras?ERK survival signalling via inactivation of the HSP90/multichaperone complex, and causes developmental injury in vivo. PMID:17331071

Chan, Wen-Hsiung

2007-01-01

389

Single and double [ital K]-shell ionization and electron-transfer cross sections for Fe and Ni bombarded by S ions and Fe by Si ions at 1. 25--4. 70 MeV/amu  

SciTech Connect

Single and double [ital K]-shell vacancy production and [ital K]-[ital K] electron-transfer cross sections have been measured in the limit of zero target thickness for Fe and Ni induced by 1.25--4.70 MeV/amu [sup 28]Si and [sup 32]S ions. The fluorescence yield [omega][sub [ital k

Tribedi, L.C.; Prasad, K.G.; Tandon, P.N. (Tata Institute of Fundamental Research, Bombay 400005 (India)); Chen, Z.; Lin, C.D. (Department of Physics, Kansas State University, Manhattan, Kansas (United States))

1994-02-01

390

OSL and photo-transferred TL of quartz single crystals sensitized by high-dose of gamma-radiation and moderate heat-treatments.  

PubMed

This study investigates the optically stimulated luminescence (OSL) and the photo-transferred thermoluminescence (PTTL) signals in quartz single crystals showing a strong TL peak near 300°C after being sensitized by irradiation with 25kGy of gamma rays and heating at 400°C. Natural and sensitized samples were prepared from two crystals with different sensitivity levels in the 300°C TL region. Continuous-wave (CW) and linearly-modulated (LM) OSL signals were stimulated with blue light-emitting diodes during 40 and 1000s, respectively. Two components were isolated from the CW-OSL signals of sensitized samples. These components were clearly seen in LM-OSL measurements together with two long-term components. LM-OSL showed that the sensitization process considered in this study sensitized an ultrafast OSL component of these crystals. The similar behavior found for the thermal stabilities of OSL and TL signals and the dependence of these signals with sample origins suggested that the trapping site related to the ultrafast component is also related to the TL process of the sensitized peak. The PTTL signal induced by blue LEDs increased the intensity of the sensitized glow peak. On the other hand, a remarkable reduction in the intensity of this peak as a result of the accumulated effect of blue light exposure was clearly seen in both kinds of crystals. These results were explained by a mechanism of competition between optically unstable deep traps and trap levels responsible to the sensitized TL peak. PMID:25151496

Ferreira de Souza, Leonardo B; Guzzo, Pedro L; Khoury, Helen J

2014-12-01

391

Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co).  

PubMed

Cyanide-bridged metal complexes of [Fe(8)M(6)(?-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH(3)CN)(2)][PF(6)](4)?n?CH(3)CN?m?H(2)O (HL=3-(2-pyridyl)-5-[4-(diphenylamino)phenyl]-1H-pyrazole), tp(-) =hydrotris(pyrazolylborate), 1: M=Ni with n=11 and m=7, and 2: M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2(1)/n. They have tetradecanuclear cores composed of eight low-spin (LS) Fe(III) and six high-spin (HS) M(II) ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown-like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro- and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2, respectively. Ac magnetic susceptibility measurements of 1 showed frequency-dependent in- and out-of-phase signals, characteristic of single-molecule magnetism (SMM), while desolvated samples of 2 showed thermal- and photoinduced intramolecular electron-transfer-coupled spin transition (ETCST) between the [(LS-Fe(II))(3) (LS-Fe(III))(5)(HS-Co(II))(3)(LS-Co(III))(3)] and the [(LS-Fe(III))(8)(HS-Co(II))(6)] states. PMID:21830241

Mitsumoto, Kiyotaka; Oshiro, Emiko; Nishikawa, Hiroyuki; Shiga, Takuya; Yamamura, Yasuhisa; Saito, Kazuya; Oshio, Hiroki

2011-08-22

392

Significant improvement of pig cloning efficiency by treatment with LBH589 after somatic cell nuclear transfer.  

PubMed

The low success rate of animal cloning by somatic cell nuclear transfer (SCNT) associates with epigenetic aberrancy, including the abnormal acetylation of histones. Altering the epigenetic status by histone deacetylase inhibitors (HDACi) enhances the developmental potential of SCNT embryos. In the current study, we examined the effects of LBH589 (panobinostat), a novel broad-spectrum HDACi, on the nuclear reprogramming and development of pig SCNT embryos in vitro. In experiment 1, we compared the in vitro developmental competence of nuclear transfer embryos treated with different concentrations of LBH589. Embryos treated with 50 nM LBH589 for 24 hours showed a significant increase in the rate of blastocyst formation compared with the control or embryos treated with 5 or 500 nM LBH589 (32.4% vs. 11.8%, 12.1%, and 10.0%, respectively, P < 0.05). In experiment 2, we examined the in vitro developmental competence of nuclear transfer embryos treated with 50 nM LBH589 for various intervals after activation and 6-dimethylaminopurine. Embryos treated for 24 hours had higher rates of blastocyst formation than the other groups. In experiment 3, when the acetylation of H4K12 was examined in SCNT embryos treated for 6 hours with 50 nM LBH589 by immunohistochemistry, the staining intensities of these proteins in LBH589-treated SCNT embryos were significantly higher than in the control. In experiment 4, LBH589-treated nuclear transfer and control embryos were transferred into surrogate mothers, resulting in three (100%) and two (66.7%) pregnancies, respectively. In conclusion, LBH589 enhances the nuclear reprogramming and developmental potential of SCNT embryos by altering the epigenetic status and expression, and increasing blastocyst quality. PMID:23866857

Jin, Jun-Xue; Li, Suo; Gao, Qing-Shan; Hong, Yu; Jin, Long; Zhu, Hai-Ying; Yan, Chang-Guo; Kang, Jin-Dan; Yin, Xi-Jun

2013-10-01

393

Reprogramming after chromosome transfer into mouse blastomeres.  

PubMed

It is well known that oocytes can reprogram differentiated cells, allowing animal cloning by nuclear transfer. We have recently shown that fertilized zygotes retain reprogramming activities, suggesting that such activities might also persist in cleavage-stage embryos. Here, we used chromosome transplantation techniques to investigate whether the blastomeres of two-cell-stage mouse embryos can reprogram more differentiated cells. When chromosomes from one of the two blastomeres were replaced with the chromosomes of an embryonic or CD4(+) T lymphocyte donor cell, we observed nuclear reprogramming and efficient contribution of the manipulated cell to the developing blastocyst. Embryos produced by this method could be used to derive stem cell lines and also developed to term, generating mosaic "cloned" animals. These results demonstrate that blastomeres retain reprogramming activities and support the notion that discarded human preimplantation embryos may be useful recipients for the production of genetically tailored human embryonic stem cell lines. PMID:19682906

Egli, Dieter; Sandler, Vladislav M; Shinohara, Mari L; Cantor, Harvey; Eggan, Kevin

2009-08-25

394

Enhancing effects of serum-rich and cytokine-supplemented culture conditions on developing blastocysts and deriving porcine parthenogenetic embryonic stem cells  

PubMed Central

The present study was conducted to develop an effective method for establishment of porcine parthenogenetic embryonic stem cells (ppESCs) from parthenogenetically activated oocyte-derived blastocysts. The addition of 10% fetal bovine serum (FBS) to the medium on the 3rd day of oocyte culturing improved the development of blastocysts, attachment of inner cell masses (ICMs) onto feeder cells, and formation of primitive ppESC colonies. ICM attachment was further enhanced by basic fibroblast growth factor, stem cell factor, and leukemia inhibitory factor. From these attached ICMs, seven ppESC lines were established. ppESC pluripotency was verified by strong enzymatic alkaline phosphatase activity and the expression of pluripotent markers OCT3/4, Nanog, and SSEA4. Moreover, the ppESCs were induced to form an embryoid body and teratoma. Differentiation into three germ layers (ectoderm, mesoderm, and endoderm) was confirmed by the expression of specific markers for the layers and histological analysis. In conclusion, data from the present study suggested that our modified culture conditions using FBS and cytokines are highly useful for improving the generation of pluripotent ppESCs. PMID:24962410

Jung, Soo-Kyung; Kim, Hyun-Jung; Kim, Chan-Lan; Lee, Joo-Hyeong; You, Jin-Young; Lee, Eun-Song; Lim, Jeong-Mook; Yun, Seon Jong; Song, Jae-Young

2014-01-01

395

Viable calves produced by somatic cell nuclear transfer using meiotic-blocked oocytes.  

PubMed

Somatic cell nuclear transfer (SCNT) has had an enormous impact on our understanding of biology and remains a unique tool for multiplying valuable laboratory and domestic animals. However, the complexity of the procedure and its poor efficiency are factors that limit a wider application of SCNT. In this context, oocyte meiotic arrest is an important option to make SCNT more flexible and increase the number of cloned embryos produced. Herein, we show that the use of butyrolactone I in association with brain-derived neurotrophic factor (BDNF) to arrest the meiotic division for 24?h prior to in vitro maturation provides bovine (Bos indicus) oocytes capable of supporting development of blastocysts and full-term cloned calves at least as efficiently as nonarrested oocytes. Furthermore, the procedure resulted in cloned blastocysts with an 1.5- and twofold increase of POU5F1 and IFNT2 expression, respectively, which are well-known markers of embryonic viability. Mitochondrial DNA (mtDNA) copy number was diminished by prematuration in immature oocytes (718,585±34,775 vs. 595,579±31,922, respectively, control and treated groups) but was unchanged in mature oocytes (522,179±45,617 vs. 498,771±33,231) and blastocysts (816,627±40,235 vs. 765,332±51,104). To our knowledge, this is the first report of cloned offspring born to prematured oocytes, indicating that meiotic arrest could have significant implications for laboratories working with SCNT and in vitro embryo production. PMID:21740268

De Bem, Tiago H C; Chiaratti, Marcos R; Rochetti, Raquel; Bressan, Fabiana F; Sangalli, Juliano R; Miranda, Moysés S; Pires, Pedro R L; Schwartz, Kátia R L; Sampaio, Rafael V; Fantinato-Neto, Paulo; Pimentel, José R V; Perecin, Felipe; Smith, Lawrence C; Meirelles, Flávio V; Adona, Paulo R; Leal, Cláudia L V

2011-10-01

396

Modifications to improve the efficiency of zona-free mouse nuclear transfer.  

PubMed

In the present study, some modifications were made to the zona-free nuclear transfer technique in the mouse in order to achieve greater efficiency. Firstly, a 1-h interval was allowed between cumulus removal and zona pellucida digestion. Secondly, acid Tyrode's was selected for zona pellucida removal, because contrary to pronase, it allows embryo survival during parthenogenic activation in the absence of calcium. Even when the exposure time to pronase was reduced to as little as 1 min or washed with fetal calf serum to inhibit the enzyme, the percentage of lysis during activation in the absence of calcium was still very high. Thirdly, electrofusion was performed at room temperature (21 degrees C), instead of 30 degrees C as in our previous experiments. Finally, embryos were cultured in groups of 12-15, instead of individually, using a "well of the wells" system during activation and culture. When compared, parthenogenic activated control embryos showed an increase in the development to blastocyst when cultured in pairs instead of individually. By the end of the experiments and using embryonic stem (ES) cells, there was a significant increase in fusion rate (1.5-fold increase) and in development to morula/blastocyst from cleaved reconstructed embryos (1.5-fold increase) when compared with the results before the modifications. A 2.4-fold increase in overall efficiency was achieved from the oocyte to morula/blastocyst stages. PMID:16571073

Ribas, R; Oback, B; Ritchie, W; Chebotareva, T; Taylor, J; Maurício, A C; Sousa, M; Wilmut, I

2006-01-01

397

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.  

PubMed

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 development, total cell number, inner cell mass (ICM) number, trophoblast (TE) cell number and relative gene expression in yak fibroblast cells and yak-bovine SCNT embryos at various stages. The potential for development of yak-bovine SCNT embryos to blastocysts was 30+/-5.7% (mean+/-S.E.M.); the total cell number was 85.3+/-16.3, fewer than in IVF bovine embryos (106.2+/-18.2) but within the reported range (60-300). The yak-bovine SCNT blastocysts had a lower ratio of TE cells to total cells (43.9+/-8.7%) than bovine IVF embryos (59.4+/-3.4%; P<0.05) or bovine-bovine SCNT (69.5+/-5.4%; P<0.05). Also, several yak-bovine SCNT embryos had abnormal initiation of expression of both Mash2 and IL6. However, expression of vimentin, collagen, Cx43 and PSMC3 were normal in yak fibroblast cells and yak-bovine SCNT embryos. In conclusion, we inferred that the normal allocation of ICM and TE cells in yak-bovine SCNT embryos and embryo-specific gene reprogramming may be important for successful inter-species animal cloning. PMID:17416410

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

2007-05-01

398

Single-pair fluorescence resonance energy transfer analysis of mRNA transcripts for highly sensitive gene expression profiling in near real time.  

PubMed

Expression analysis of mRNAs transcribed from certain genes can be used as important sources of biomarkers for in vitro diagnostics. While the use of reverse transcription quantitative PCR (RT-qPCR) can provide excellent analytical sensitivity for monitoring transcript numbers, more sensitive approaches for expression analysis that can report results in near real-time are needed for many critical applications. We report a novel assay that can provide exquisite limits-of-quantitation and consists of reverse transcription (RT) followed by a ligase detection reaction (LDR) with single-pair fluorescence resonance energy transfer (spFRET) to provide digital readout through molecular counting. For this assay, no PCR was employed, which enabled short assay turnaround times. To facilitate implementation of the assay, a cyclic olefin copolymer (COC) microchip, which was fabricated using hot embossing, was employed to carry out the LDR in a continuous flow format with online single-molecule detection following the LDR. As demonstrators of the assay's utility, MMP-7 mRNA was expression profiled from several colorectal cancer cell lines. It was found that the RT-LDR/spFRET assay produced highly linear calibration plots even in the low copy number regime. Comparison to RT-qPCR indicated a better linearity over the low copy number range investigated (10-10,000 copies) with an R(2) = 0.9995 for RT-LDR/spFRET and R(2) = 0.98 for RT-qPCR. In addition, differentiating between copy numbers of 10 and 50 could be performed with higher confidence using RT-LDR/spFRET. To demonstrate the short assay turnaround times obtainable using the RT-LDR/spFRET assay, a two thermal cycle LDR was carried out on amphiphysin gene transcripts that can serve as important diagnostic markers for ischemic stroke. The ability to supply diagnostic information on possible stroke events in short turnaround times using RT-LDR/spFRET will enable clinicians to treat patients effectively with appropriate time-sensitive therapeutics. PMID:23869556

Peng, Zhiyong; Young, Brandon; Baird, Alison E; Soper, Steven A

2013-08-20

399

Transfer form  

Cancer.gov

10/02 Transfer Investigational Agent Form This form is to be used for an intra-institutional transfer, one transfer/form. Division of Cancer Prevention National Cancer Institute National Institutes of Health TRANSFER FROM: Investigator transferring agent:

400

Transcriptional reprogramming of gene expression in bovine somatic cell chromatin transfer embryos  

PubMed Central

Background Successful reprogramming of a somatic genome to produce a healthy clone by somatic cells nuclear transfer (SCNT) is a rare event and the mechanisms involved in this process are poorly defined. When serial or successive rounds of cloning are performed, blastocyst and full term development rates decline even further with the increasing rounds of cloning. Identifying the "cumulative errors" could reveal the epigenetic reprogramming blocks in animal cloning. Results Bovine clones from up to four generations of successive cloning were produced by chromatin transfer (CT). Using Affymetrix bovine microarrays we determined that the transcriptomes of blastocysts derived from the first and the fourth rounds of cloning (CT1 and CT4 respectively) have undergone an extensive reprogramming and were more similar to blastocysts derived from in vitro fertilization (IVF) than to the donor cells used for the first and the fourth rounds of chromatin transfer (DC1 and DC4 respectively). However a set of transcripts in the cloned embryos showed a misregulated pattern when compared to IVF embryos. Among the genes consistently upregulated in both CT groups compared to the IVF embryos were genes involved in regulation of cytoskeleton and cell shape. Among the genes consistently upregulated in IVF embryos compared to both CT groups were genes involved in chromatin remodelling and stress coping. Conclusion The present study provides a data set that could contribute in our understanding of epigenetic errors in somatic cell chromatin transfer. Identifying "cumulative errors" after serial cloning could reveal some of the epigenetic reprogramming blocks shedding light on the reprogramming process, important for both basic and applied research. PMID:19393066

Rodriguez-Osorio, Nelida; Wang, Zhongde; Kasinathan, Poothappillai; Page, Grier P; Robl, James M; Memili, Erdogan

2009-01-01

401

Fabricating metal-oxide-semiconductor field-effect transistors on a polyethylene terephthalate substrate by applying low-temperature layer transfer of a single-crystalline silicon layer by meniscus force  

SciTech Connect

A low-temperature local-layer technique for transferring a single-crystalline silicon (c-Si) film by using a meniscus force was proposed, and an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) was fabricated on polyethylene terephthalate (PET) substrate. It was demonstrated that it is possible to transfer and form c-Si films in the required shape at the required position on PET substrates at extremely low temperatures by utilizing a meniscus force. The proposed technique for layer transfer was applied for fabricating high-performance c-Si MOSFETs on a PET substrate. The fabricated MOSFET showed a high on/off ratio of more than 10{sup 8} and a high field-effect mobility of 609 cm{sup 2} V{sup ?1} s{sup ?1}.

Sakaike, Kohei; Akazawa, Muneki; Nakamura, Shogo [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan)] [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan); Higashi, Seiichiro [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan) [Department of Semiconductor Electronics and Integration Science, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, Hiroshima 739-8530 (Japan); Research Institute for Nanodevice and Bio Systems, Hiroshima University, Kagamiyama 1-4-2, Higashihiroshima, Hiroshima 739-8527 (Japan)

2013-12-02