WorldWideScience

Sample records for twin gas jet-assisted

  1. Selection of the most influential factors on the water-jet assisted underwater laser process by adaptive neuro-fuzzy technique

    Science.gov (United States)

    Nikolić, Vlastimir; Petković, Dalibor; Lazov, Lyubomir; Milovančević, Miloš

    2016-07-01

    Water-jet assisted underwater laser cutting has shown some advantages as it produces much less turbulence, gas bubble and aerosols, resulting in a more gentle process. However, this process has relatively low efficiency due to different losses in water. It is important to determine which parameters are the most important for the process. In this investigation was analyzed the water-jet assisted underwater laser cutting parameters forecasting based on the different parameters. The method of ANFIS (adaptive neuro fuzzy inference system) was applied to the data in order to select the most influential factors for water-jet assisted underwater laser cutting parameters forecasting. Three inputs are considered: laser power, cutting speed and water-jet speed. The ANFIS process for variable selection was also implemented in order to detect the predominant factors affecting the forecasting of the water-jet assisted underwater laser cutting parameters. According to the results the combination of laser power cutting speed forms the most influential combination foe the prediction of water-jet assisted underwater laser cutting parameters. The best prediction was observed for the bottom kerf-width (R2 = 0.9653). The worst prediction was observed for dross area per unit length (R2 = 0.6804). According to the results, a greater improvement in estimation accuracy can be achieved by removing the unnecessary parameter.

  2. Development of a jet-assisted polycrystalline diamond drill bit

    Energy Technology Data Exchange (ETDEWEB)

    Pixton, D.S.; Hall, D.R.; Summers, D.A.; Gertsch, R.E.

    1997-12-31

    A preliminary investigation has been conducted to evaluate the technical feasibility and potential economic benefits of a new type of drill bit. This bit transmits both rotary and percussive drilling forces to the rock face, and augments this cutting action with high-pressure mud jets. Both the percussive drilling forces and the mud jets are generated down-hole by a mud-actuated hammer. Initial laboratory studies show that rate of penetration increases on the order of a factor of two over unaugmented rotary and/or percussive drilling rates are possible with jet-assistance.

  3. Arc Interference Behavior during Twin Wire Gas Metal Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Dingjian Ye

    2013-01-01

    Full Text Available In order to study arc interference behavior during twin wire gas metal arc welding process, the synchronous acquisition system has been established to acquire instantaneous information of arc profile including dynamic arc length variation as well as relative voltage and current signals. The results show that after trailing arc (T-arc is added to the middle arc (M-arc in a stable welding process, the current of M arc remains unchanged while the agitation increases; the voltage of M arc has an obvious increase; the shape of M arc changes, with increasing width, length, and area; the transfer frequency of M arc droplet increases and the droplet itself becomes smaller. The wire extension length of twin arc turns out to be shorter than that of single arc welding.

  4. Performance optimization of water-jet assisted underwater laser cutting of AISI 304 stainless steel sheet

    Science.gov (United States)

    Mullick, Suvradip; Madhukar, Yuvraj K.; Roy, Subhransu; Nath, Ashish K.

    2016-08-01

    Recent development of water-jet assisted underwater laser cutting has shown some advantages over the gas assisted underwater laser cutting, as it produces much less turbulence, gas bubble and aerosols, resulting in a more gentle process. However, this process has relatively low efficiency due to different losses in water. Scattering is reported to be a dominant loss mechanism, which depends on the growth of vapor layer at cut front and its removal by water-jet. Present study reports improvement in process efficiency by reducing the scattering loss using modulated laser power. Judicious control of laser pulse on- and off-time could improve process efficiency through restricting the vapor growth and its effective removal by water-jet within the laser on- and off-time, respectively. Effects of average laser power, duty cycle and modulation frequency on specific energy are studied to get an operating zone for maximum efficiency. Next, the variation in laser cut quality with different process parameters are studied within this operating zone using Design of experiment (DOE). Response surface methodology (RSM) is used by implementing three level Box-Behnken design to optimize the variation in cut quality, and to find out the optimal process parameters for desired quality. Various phenomena and material removal mechanism involved in this process are also discussed.

  5. Twin-Wire Pulsed Tandem Gas Metal Arc Welding of API X80 Steel Linepipe

    Directory of Open Access Journals (Sweden)

    Wenhao Wu

    2018-01-01

    Full Text Available Twin-Wire Pulsed Tandem Gas Metal Arc Welding process with high welding production efficiency was used to join the girth weld seam of API X80 steel linepipe of 18.4 mm wall thickness and 1422 mm diameter. The macrostructure, microstructure, hardness, and electrochemical corrosion behavior of welded joints were studied. Effects of temperature and Cl− concentration on the corrosion behavior of base metal and weld metal were investigated. Results show that the welded joint has good morphology, mechanical properties, and corrosion resistance. The corrosion resistance of both the base metal and the weld metal decreases with increasing temperature or Cl− concentration. In the solution with high Cl− concentration, the base metal and weld metal are more susceptible to pitting. The corrosion resistance of the weld metal is slightly lower than that of the base metal.

  6. Development and Testing of a Jet Assisted Polycrystalline Diamond Drilling Bit. Phase II Development Efforts

    Energy Technology Data Exchange (ETDEWEB)

    David S. Pixton

    1999-09-20

    Phase II efforts to develop a jet-assisted rotary-percussion drill bit are discussed. Key developments under this contract include: (1) a design for a more robust polycrystalline diamond drag cutter; (2) a new drilling mechanism which improves penetration and life of cutters; and (3) a means of creating a high-pressure mud jet inside of a percussion drill bit. Field tests of the new drill bit and the new robust cutter are forthcoming.

  7. The machinability of nickel-based alloys in high-pressure jet assisted (HPJA turning

    Directory of Open Access Journals (Sweden)

    D. Kramar

    2013-10-01

    Full Text Available Due to their mechanical, thermal and chemical properties, nickel-based alloys are generally included among materials that are hard to machine. An experimental study has been performed to investigate the capabilities of conventional and high-pressure jet assisted (HPJA turning of hard-to-machine materials, namely Inconel 718. The capabilities of different hard turning procedures are compared by means of chip breakability. The obtained results show that HPJA method offers a significant increase in chip breakability, under the same cutting conditions (cutting speed, feed rate, depth of cut.

  8. Ink jet assisted metallization for low cost flat plate solar cells

    Science.gov (United States)

    Teng, K. F.; Vest, R. W.

    1987-01-01

    Computer-controlled ink-jet-assisted metallization of the front surface of solar cells with metalorganic silver inks offers a maskless alternative method to conventional photolithography and screen printing. This method can provide low cost, fine resolution, reduced process complexity, avoidance of degradation of the p-n junction by firing at lower temperature, and uniform line film on rough surface of solar cells. The metallization process involves belt furnace firing and thermal spiking. With multilayer ink jet printing and firing, solar cells of about 5-6 percent efficiency without antireflection (AR) coating can be produced. With a titanium thin-film underlayer as an adhesion promoter, solar cells of average efficiency 8.08 percent without AR coating can be obtained. This efficiency value is approximately equal to that of thin-film solar cells of the same lot. Problems with regard to lower inorganic content of the inks and contact resistance are noted.

  9. Performance based diagnostics of a twin shaft aeroderivative gas turbine: water wash scheduling

    OpenAIRE

    Baudin Lastra, Tomas

    2015-01-01

    Aeroderivative gas turbines are used all over the world for different applications as Combined Heat and Power (CHP), Oil and Gas, ship propulsion and others. They combine flexibility with high efficiencies, low weight and small footprint, making them attractive where power density is paramount as off shore Oil and Gas or ship propulsion. In Western Europe they are widely used in CHP small and medium applications thanks to their maintainability and efficiency. Reliability, Av...

  10. Possibilities of Application of High Pressure Jet Assisted Machining in Hard Turning with Carbide Tools

    Directory of Open Access Journals (Sweden)

    G. Globočki Lakić

    2017-06-01

    Full Text Available High Pressure Jet Assisted Machining (HPJAM in turning is a hybrid machining method in which a high pressure jet of cooling and lubrication fluid, under high pressure (50 MPa, leads to the zone between the cutting tool edge and workpiece. An experimental study was performed to investigate the capabilities of conventional and high pressure cooling (HPC in the turning of hard-to-machine materials: hard-chromed and surface hardened steel Ck45 (58 HRc and hardened bearing steel 100Cr6 (62 HRc. Machining experiments were performed using coated carbide tools and highly cutting speed. Experimental measurements were performed for different input process parameters. The cooling capabilities are compared by monitoring of tool wear, tool life, cooling efficiency, and surface roughness. Connection between the tool wear and surface roughness is established. Experimental research show that the hard turning with carbide cutting tools and HP supply CLF provides numerous advantages from the techno-economic aspect: greater productivity, reduce of temperature in the cutting zone, improved control chip formation, extended tool life, low intensity of tool wear, surface roughness in acceptable limits, significant reduce of production costs related to the CLF.

  11. Conceptual Mean-Line Design of Single and Twin-Shaft Oxy-Fuel Gas Turbine in a Semiclosed Oxy-Fuel Combustion Combined Cycle.

    Science.gov (United States)

    Sammak, Majed; Thorbergsson, Egill; Grönstedt, Tomas; Genrup, Magnus

    2013-08-01

    The aim of this study was to compare single- and twin-shaft oxy-fuel gas turbines in a semiclosed oxy-fuel combustion combined cycle (SCOC-CC). This paper discussed the turbomachinery preliminary mean-line design of oxy-fuel compressor and turbine. The conceptual turbine design was performed using the axial through-flow code luax-t, developed at Lund University. A tool for conceptual design of axial compressors developed at Chalmers University was used for the design of the compressor. The modeled SCOC-CC gave a net electrical efficiency of 46% and a net power of 106 MW. The production of 95% pure oxygen and the compression of CO 2 reduced the gross efficiency of the SCOC-CC by 10 and 2 percentage points, respectively. The designed oxy-fuel gas turbine had a power of 86 MW. The rotational speed of the single-shaft gas turbine was set to 5200 rpm. The designed turbine had four stages, while the compressor had 18 stages. The turbine exit Mach number was calculated to be 0.6 and the calculated value of AN 2 was 40 · 10 6 rpm 2 m 2 . The total calculated cooling mass flow was 25% of the compressor mass flow, or 47 kg/s. The relative tip Mach number of the compressor at the first rotor stage was 1.15. The rotational speed of the twin-shaft gas generator was set to 7200 rpm, while that of the power turbine was set to 4800 rpm. A twin-shaft turbine was designed with five turbine stages to maintain the exit Mach number around 0.5. The twin-shaft turbine required a lower exit Mach number to maintain reasonable diffuser performance. The compressor turbine was designed with two stages while the power turbine had three stages. The study showed that a four-stage twin-shaft turbine produced a high exit Mach number. The calculated value of AN 2 was 38 · 10 6 rpm 2 m 2 . The total calculated cooling mass flow was 23% of the compressor mass flow, or 44 kg/s. The compressor was designed with 14 stages. The preliminary design parameters of the turbine and

  12. Twin pregnancy

    DEFF Research Database (Denmark)

    Sperling, Lene; Tabor, A

    2001-01-01

    Determination of chorionicity is one of the most important issues in the management of twin pregnancy. Modern ultrasound equipment has made it possible to accurately assess placentation already in the first trimester with the lambda sign. With regard to prenatal diagnosis, it is important to know...... for clinicians caring for twin pregnancies....

  13. Conjoined Twins

    Science.gov (United States)

    ... individuals. Eight to 12 days after conception, the embryonic layers that will split to form monozygotic twins begin to develop into specific organs and structures. It's believed that when the embryo ...

  14. Twin-twin transfusion syndrome.

    Science.gov (United States)

    Rossi, A C; D'addario, V

    2009-04-01

    Twin-twin transfusion syndrome (TTTS) is a condition unique to monochorionic pregnancies, although very few case reports described the syndrome in dichorionic placentas. The aetiology of TTTS relies in the presence of at least 1 arterio-venous placental anastomosis, through which unequal blood exchange from one twin (donor) to the co-twin (recipient) occurs. The diagnosis of TTTS relies on the sonographic detection of oligohydramnios in the donor's sac and polyhydramnios in the recipient's sac in the second trimester, although signs of TTTS are present since the first trimester. Treatment options for TTTS include serial amnioreduction, septostomy, selective feticide of the apparently sick twin, and selective photocoagulation of placental vessels (SLPCV). Because of the growing evidence that SLPCV is the most efficacious therapy compared to amnioreduction with/without septostomy, the authors reviewed in details the effects of SLPCV on fetal growth and circulation. The authors further explore literature with regard to the prognostic factors. Finally, because Quintero staging system is actually under debate, they discuss the most recent findings on this topic and propose a new staging system to assess severity of TTTS at presentation (Rossi staging system). New topics for future research, which would probably further clarify the natural history of TTTS, are also proposed.

  15. Preparing for Twins

    Science.gov (United States)

    ... or fraternal, all twins have their individual personalities, styles, and temperament. Both identical and fraternal twins may ... you on how to cope with the special parenting challenges with twins. He also can suggest helpful ...

  16. Twin Peaks

    Science.gov (United States)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.The image was taken by the Imager for Mars Pathfinder (IMP) after its deployment on Sol 3. Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  17. Twin-domain size and bulk oxygen in-diffusion kinetics of YBa2Cu3O6+x studied by neutron powder diffraction and gas volumetry

    DEFF Research Database (Denmark)

    Poulsen, H.F.; Andersen, N.H.; Lebech, B.

    1991-01-01

    We report experimental results of twin-domain size and bulk oxygen in-diffusion kinetics of YBa2Cu3O6+x, which supplement a previous and simultaneous study of the structural phase diagram and oxygen equilibrium partial pressure. Analysis of neutron powder diffraction peak broadening show features...... which are identified to result from temperature independent twin-domain formation in to different orthorhombic phases with domain sizes 250 and 350 angstrom, respectively. The oxygen in-diffusion flow shows simple relaxation type behaviour J = J0 exp(-t/tau) despite a rather broad particle size...... distribution. At higher temperatures, tau is activated with activation energies 0.55 and 0.25 eV in the tetragonal and orthorhombic phases, respectively. Comparison between twin-domain sizes and bulk oxygen in-diffusion time constants indicates that the twin-domain boundaries may contribute to the effective...

  18. The Qingdao Twin Registry

    DEFF Research Database (Denmark)

    Duan, Haiping; Ning, Feng; Zhang, Dongfeng

    2013-01-01

    In 1998, the Qingdao Twin Registry was initiated as the main part of the Chinese National Twin Registry. By 2005, a total of 10,655 twin pairs had been recruited. Since then new twin cohorts have been sampled, with one longitudinal cohort of adolescent twins selected to explore determinants...... of metabolic disorders and health behaviors during puberty and young adulthood. Adult twins have been sampled for studying heritability of multiple phenotypes associated with metabolic disorders. In addition, an elderly twin cohort has been recruited with a focus on genetic studies of aging-related phenotypes...

  19. Pathophysiology of twin to twin transfuzion syndrome

    Directory of Open Access Journals (Sweden)

    Šulović Nenad

    2014-01-01

    Full Text Available Twin-twin transfusion syndrome (TTTTS is a pathological condition whereby a donor fetus bleeds into the circulation of a recipient fetus through the abnormal inter-twin placental anastomoses. The donor twin becomes anemic, hypovolemic, growth restricted, and as a consequence has a reduced urinary production. Since swallowing of the fluid is not impaired, the amniotic fluid volume progressively decreases. The recipient twin becomes hypervolemic. Lacking a mechanism to remove blood, the recipient twin eliminates as much fluid as possible, thus becoming hypercytemic or even hydropic in the more severe cases. The elevated urinary production from the recipient twin leads to polyhydramnios and an overdistension of the amniotic cavity, that compresses the donor and it's vascular supply against the uterine wall, further decreasing perfusion to the donor fetus. The reduction in amniotic fluid on the donor side results in a close apposition of the inter-twin membrane that fixes the donor fetus to the uterus, a condition nicknamed 'stuck twin'.

  20. Monochorionic twin pregnancies

    NARCIS (Netherlands)

    Hack, K.E.A.

    2008-01-01

    Following widespread application of assisted reproductive technology modalities and the increased age of motherhood, the incidence of twin gestations has increased markedly. Twins are either monozygotic or dizygotic. Dizygotic (i.e. fraternal) twins result from the fertilization of two different

  1. Twin-twin Transfusion Syndrome with a Single Ectopic Kidney in a Twin Donor. Case Presentation

    OpenAIRE

    Gerardo Rogelio Robaina Castellanos; Solangel de la Caridad Riesgo Rodríguez; Esther María Tristá Ricardo

    2016-01-01

    Twin-twin Transfusion Syndrome presents more frequently in diamniotic monochromic twins. In advanced stages and without prenatal intervention, is associated to high rates of peri natal mortality and neurological sequel in the survivors. It is presented a case of a pair of twins with severe depression at birth in which it was diagnosed a Twin-twin Transfusion Syndrome, later confirmed with the presence of anemia in the donor twin and polycythemia in the receptor twin. Both twins had an unfavou...

  2. Perinatal hepatic infarction in twin-twin transfusion.

    LENUS (Irish Health Repository)

    O'Sullivan, M J

    2012-02-03

    We report a case of a twin pregnancy which was complicated by a twin-twin transfusion in which the recipient twin was noted to have an intra-abdominal echogenic mass. This twin died at two days of age of hepatic infarction. The donor twin was healthy at birth, at thirty weeks\\' gestation, and did not have any subsequent problems. Fetal intra-abdominal echogenicity may be a marker of hepatic infarction.

  3. The Danish Twin Register

    DEFF Research Database (Denmark)

    Kyvik, K O; Christensen, Kaare; Skytthe, A

    1996-01-01

    BACKGROUND: Population based twin registers represent a valuable tool for genetic epidemiological research, since twin studies aim at separating the effect of genes and environment for complex traits. The Danish Twin Register's history, size, ascertainment and completeness of data, as well as dat......-1952 og 1983-1993 are being ascertained at the moment. The register is available for research given certain conditions are fulfilled. CONCLUSION: This register will in a few years be the most comprehensive twin register in the world. It is a very valuable Danish research resource....

  4. Conjoined (Siamese) Twins in Zambia

    African Journals Online (AJOL)

    year-old Zambian multiparous mother gave birth to a set of twins with two heads ... (symmetric or mirror image) but one twin attached with an incomplete foetus is known as hetropagtrs. (asymmetrical). Thoracopagus twins (joined at the chest).

  5. The collection of Adipose Derived Stem Cells using Water Jet Assisted Lipoplasty for their use in Plastic and Reconstructive Surgery: a preliminary study

    Directory of Open Access Journals (Sweden)

    Valeria Purpura

    2016-11-01

    Full Text Available The graft of autologous fat for the augmentation of soft tissue is a common practice frequently used in the field of plastic and reconstructive surgery. In addition, the presence of adipose derived stem cells (ASCs in adipose tissue stimulates the regeneration of tissue in which it is applied after the autologous fat grafting improving the final clinical results. Due to these characteristics, there is an increasing interest in the use of ASCs for the treatment of several clinical conditions. As a consequence, the use of clean room environment is required for the production of cell-based therapies. The present study is aimed to describe the biological properties of adipose tissue and cells derived from it cultured in vitro in clean room environment according to current regulation. The collection of adipose tissue was performed using the water – jet assisted liposuction in order to preserve an high cell viability increasing their chances of future use for different clinical application in the field of plastic and reconstructive surgery.

  6. The Danish Twin Registry

    DEFF Research Database (Denmark)

    Skytthe, Axel; Ohm Kyvik, Kirsten; Vilstrup Holm, Niels

    2011-01-01

    Introduction: The Danish Twin Registry is a unique source for studies of genetic, familial and environmental factors on life events, health conditions and diseases. Content: More than 85,000 twin pairs born 1870-2008 in Denmark. Validity and coverage: Four main ascertainment methods have been emp...

  7. Rotational Twin Paradox

    Science.gov (United States)

    Smarandache, Florentin

    2012-10-01

    Two twins settle on a massive spherical planet at a train station S. Let's consider that each twin has an accompanying clock, and the two clocks are synchronized. One twin T1 remains in the train station, while the other twin T2 travels at a uniform high speed with the train around the planet (on the big circle of the planet) until he gets back to the same train station S. Assume the planet is not rotating. Since the planet is massive, we can consider that on a very small part on its surface the train rail road is linear, so the train is in a linear uniform motion. The larger is the planet's radius the more the rail road approaches a linear trajectory. Because the GPS clocks are alleged to be built on the Theory of Relativity, one can consider the twin T2 train's circular trajectory alike the satellite's orbit. In addition, the gravitation is the same for the reference frames of T1 and T2. Each twin sees the other twin as traveling, therefore each twin finds the other one has aged slower than him. Thus herein we have a relativistic symmetry. When T2 returns to train station S, he finds out that he is younger than T1 (therefore asymmetry). Thus, one gets a contradiction between symmetry and asymmetry.

  8. Neonatal status of twins

    Directory of Open Access Journals (Sweden)

    Božinović Dragica

    2012-01-01

    Full Text Available Multiple pregnancy is a pregnancy where more than one fetus develops simultaneously in the womb, as a result of the ovulation and fertilization of more than one egg. It is relatively rare in humans and represents the rest of the phylogenetic stages. The most common are twins and they indicate the development of two fetuses in the womb. The frequency of twin pregnancies is about 1%. Multiple pregnancies belong to a group of high-risk pregnancies because of the many complications that occur during the pregnancy: higher number of premature deliveries, bleeding, early neonatal complications and higher perinatal morbidity and mortality. Such pregnancies and infants require greater supervision and monitoring. The aim of this study was to determine the percentage of baby twins born at the maternity ward of the General Hospital in Prokuplje and their morbidity and mortality. Data on the total number of deliveries, number of twins, parity and maternal age, gestational age, body weight of twins, method of delivery, Apgar score and perinatal mortality were collected and statistically analyzed by means of retrospective analysis of operative birth and neonatal protocol for 6 years (2005 of 2010. Out of 4527 mothers who gave birth 43 were pairs of twins, or 0.95% of women gave birth to twins. These babies are more likely born by Caesarean section, but delivered with slightly lower birth weight.

  9. SUSY Meets Her Twin

    CERN Document Server

    Katz, Andrey; Pokorski, Stefan; Redigolo, Diego; Ziegler, Robert

    2017-01-31

    We investigate the general structure of mirror symmetry breaking in the Twin Higgs scenario. We show, using the IR effective theory, that a significant gain in fine tuning can be achieved if the symmetry is broken hardly. We emphasize that weakly coupled UV completions can naturally accommodate this scenario. We analyze SUSY UV completions and present a simple Twin SUSY model with a tuning of around 10% and colored superpartners as heavy as 2 TeV. The collider signatures of general Twin SUSY models are discussed with a focus on the extended Higgs sectors.

  10. Jejunal atresia in twins

    NARCIS (Netherlands)

    Moorman-Voestermans, C. G.; Heij, H. A.; Vos, A.

    1990-01-01

    In the past 2 1/2 years a sudden increase in the frequency of jejunal atresia in discordant, nonidentical twins was observed. Reported are the details of 11 cases and some reflections on possible pathogenetic mechanisms involved

  11. The 16th International Twin Congress: Highlights from Madrid/Twin Research: Twin Study of Partner Aggression; ABO Incompatibility in Dizygotic Twins; Growth Discordance in a Monoamniotic Twin Pair; Quick Note on Twin Implantation/In the Media: Long-Lost Twins Found; NASA Twin Experiment; Twin Brothers and the Las Vegas Attack; Retired Twin Airline Pilots; Twin Film Clips.

    Science.gov (United States)

    Segal, Nancy L

    2018-02-01

    Highlights from the 16th International Twin Congress, held in Madrid, Spain from November 16-18, 2017, are presented. The Twin Congress, formerly held every three years, now takes place biennially with a single-day meeting organized during the off years. This meeting is the largest gathering of scientific twin researchers, medical personnel, and representatives of multiple birth organizations in the world. This overview is followed by reviews of recent twin research and commentary concerning partner aggression, ABO incompatibility in dizygotic twins, growth discordance in a monoamniotic twin pair and twin implantation. The article closes with summaries of timely topics in the media, namely a father's finding of his long-lost twin children, early results from the NASA twin experiment, twin brothers at the center of the October 2017 Las Vegas attack, retired twin airline pilots, and clips from recent films with twin-based themes.

  12. Dogs discriminate identical twins.

    Directory of Open Access Journals (Sweden)

    Ludvík Pinc

    Full Text Available Earlier studies have shown variation among experimental attempts to establish whether human monozygotic twins that are genetically identical also have identical individual scents. In none of the cases were the dogs able to distinguish all the individual scents of monozygotic twins living in the same environment if the scents were presented to them separately. Ten specially trained police German Shepherd dogs of three Czech Republic Police Regional Headquarters were used for scent identification in our study. The dogs were supposed to match scents of two monozygotic pairs (5 and 7 years old and two dizygotic twin pairs (8 and 13 years old. Scents were collected on cotton squares stored in glass jars. Dog handlers were blind to the experiment details. In each trial (line-up, one scent was used as a starting scent and the dog was then sent to determine if any of the 7 presented glass jars contained a matching scent. Scents of children of similar ages were used as distractors. In the matching procedure, the dogs matched correctly the scent of one twin with the other, as well as two scents collected from every single identical and non-identical twin to prove their efficacy and likewise, the presence of the matching twin scent in any given glass jar. All dogs in all trials distinguished correctly the scents of identical as well as non-identical twins. All dogs similarly matched positively two scents collected from the same individuals. Our findings indicated that specially trained German Shepherd dogs are able to distinguish individual scents of identical twins despite the fact that they live in the same environment, eat the same food and even if the scents are not presented to them simultaneously.

  13. Dogs Discriminate Identical Twins

    Science.gov (United States)

    Pinc, Ludvík; Bartoš, Luděk; Reslová, Alice; Kotrba, Radim

    2011-01-01

    Earlier studies have shown variation among experimental attempts to establish whether human monozygotic twins that are genetically identical also have identical individual scents. In none of the cases were the dogs able to distinguish all the individual scents of monozygotic twins living in the same environment if the scents were presented to them separately. Ten specially trained police German Shepherd dogs of three Czech Republic Police Regional Headquarters were used for scent identification in our study. The dogs were supposed to match scents of two monozygotic pairs (5 and 7 years old) and two dizygotic twin pairs (8 and 13 years old). Scents were collected on cotton squares stored in glass jars. Dog handlers were blind to the experiment details. In each trial (line-up), one scent was used as a starting scent and the dog was then sent to determine if any of the 7 presented glass jars contained a matching scent. Scents of children of similar ages were used as distractors. In the matching procedure, the dogs matched correctly the scent of one twin with the other, as well as two scents collected from every single identical and non-identical twin to prove their efficacy and likewise, the presence of the matching twin scent in any given glass jar. All dogs in all trials distinguished correctly the scents of identical as well as non-identical twins. All dogs similarly matched positively two scents collected from the same individuals. Our findings indicated that specially trained German Shepherd dogs are able to distinguish individual scents of identical twins despite the fact that they live in the same environment, eat the same food and even if the scents are not presented to them simultaneously. PMID:21698282

  14. Hypoalbuminemia in Donors with Twin-Twin Transfusion Syndrome

    NARCIS (Netherlands)

    Verbeek, L.; Middeldorp, J. M.; Hulzebos, C. V.; Oepkes, D.; Walther, F. J.; Lopriore, E.

    2013-01-01

    Objective: To estimate the differences in albumin levels between donors and recipients with twin-twin transfusion syndrome (TTTS). Methods: We performed a matched case-control study including twin pairs with TTTS treated conservatively (conservative group) or with fetoscopic laser surgery (laser

  15. Dialysis for twins

    DEFF Research Database (Denmark)

    Gramkow, Ann-Maria; Aarup, Michael; Andersen, L. L. T.

    2014-01-01

    A 32-year-old woman with known stage-4 chronic kidney disease due to lupus nephritis presented with twin pregnancy after in vitro fertilization at a gestational age of 24 weeks + 3 days because of imminent preterm labour. Repeated ultrasound evaluations confirmed intrauterine growth restriction...... in both twins and polyhydramnios as the cause of imminent preterm labour. After initiation of haemodialysis treatment, ultrasound evaluation showed a significant decrease in amniotic fluids, and also reduction in blood urea nitrogen and in clinical complaints could be observed. At a gestational age of 28...... weeks + 4 days, delivery was performed by Caesarean section. This case study shows that effective treatment of elevated uraemic toxins significantly reduced the morbidity risks of the twins....

  16. Imaging of conjoined twins

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Kieran [Great Ormond Street Hospital for Children, Department of Radiology, London (United Kingdom); Kiely, Edward M.; Spitz, Lewis [Great Ormond Street Hospital for Children, Department of Surgery, London (United Kingdom)

    2006-09-15

    The incidence of conjoined twins is estimated to be around 1 in 250,000 live births. There is a distinct female predominance. In this paper the imaging of conjoined twins both antenatally and postnatally is reviewed, in particular taking into consideration recent advances with multidetector CT. Accurate counselling of parents regarding the likely outcome of the pregnancy and the likelihood of successful separation is dependent on good prenatal imaging with ultrasound and MRI. Planning of postnatal surgical separation is aided by accurate preoperative imaging which, depending on the conjoined area, will encompass many imaging modalities, but often relies heavily on CT scanning. (orig.)

  17. Reflections on twin relationships: twins reared apart and twins of opposite gender.

    Science.gov (United States)

    Segal, Nancy L

    2012-12-01

    The complexities of twin relationships posed by separate rearing and by opposite sex are considered. Unusual cases may highlight unique social-interactional processes and outcomes occurring in these pairs. Research reviews include recent twin studies on second language acquisition, political behavior, and multiple birth rates. Items of more general interest include twin 'cousins' reared apart, indistinguishable monozygotic quadruplets, a genetic testing dilemma, and a performance about separated twins.

  18. Mitral valve regurgitation in twins

    DEFF Research Database (Denmark)

    Bakkestrøm, Rine; Larsen, Lisbeth Aagaard; Møller, Jacob Eifer

    2016-01-01

    BACKGROUND: Smaller observational studies have suggested familial clustering of mitral regurgitation (MR). Using a large twin cohort, the aims were to assess MR concordance rates and assess mortality in MR twins and unaffected cotwins. METHODS: Through the Danish Twin Registry, twins with an Inte.......57, 95% CI 1.86-3.54). Overall there was no increased mortality risk for unaffected cotwins to MR cases compared with matched controls (HR 1.02, 95% CI 0.90-1.17) except for first year of life (HR 1.92, 95% CI 1.10-3.36) and for monozygotic twins older than 65 years (HR 1.49, 95% CI 1...

  19. Anaesthesia for conjoined twins

    African Journals Online (AJOL)

    draw~ver patient system consisting of a paediatric. "Ambu" bag and "Paedivalven drawing oxygen-en- riched air through a halothane vaporiser. Oxygen was supplied from an electric oxygen concentrator which can give 2 litres of 95% oxygen per minute. This apparatus has been described I. Mter 3 minutes the Sa02 of Twin ...

  20. Twin Hub Network (poster)

    NARCIS (Netherlands)

    Kreutzberger, E.D.; Konings, J.W.

    2014-01-01

    Twin hub network, a European Interreg IVB project, aims at making intermodal rail transport within, to and from North West Europe more competitive, in particular between seaports and inland terminals. Improving rail competitiveness enables to shift freight flows from road to rail, providing a more

  1. Sleep Terrors in Twins

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-12-01

    Full Text Available In an attempt to clarify the genetic and environmental causes of sleep terrors in childhood, reasearchers in Canada followed 390 pairs of monozygotic and dizygotic twins by assessing the frequency of sleep terrors at 18 and 30 months of age using a questionnaire administered to the biological mothers.

  2. Sleep Terrors in Twins

    OpenAIRE

    J Gordon Millichap

    2008-01-01

    In an attempt to clarify the genetic and environmental causes of sleep terrors in childhood, reasearchers in Canada followed 390 pairs of monozygotic and dizygotic twins by assessing the frequency of sleep terrors at 18 and 30 months of age using a questionnaire administered to the biological mothers.

  3. Twin-twin transfusion syndrome - diagnosis and prognosis

    Directory of Open Access Journals (Sweden)

    Hajrić-Egić Amira

    2003-01-01

    Full Text Available Twin-twin transfusion syndrome is a serious complication of monozygotic, monochorionic, diamniotic twins resulting from transplacental vascular communications. In this syndrome blood is thought to be shunted from one twin - donor,who develops anaemia,growth retardation and oligoamnios, to the other twin - recipient,who becomes plethoric,macrosomic and develops polyhydroamnios. The incidence of twin-twin transfusion syndrome ranges from 5-15% of all twin pregnancies. If this condition develops in the second trimester, it is usually associated with spontaneous abortion and death of one or both fetuses before viability. Developing the syndrome in the third trimester has better perinatal outcome. Mortality rates ranging from 56%-100%, depending on gestational age and severity of the syndrome. The ultrasound criterias for diagnosis, in this study,were the presence of twins of the same sex with discordant growth, with oligohydroamnios in one twin sac and polyhydroamnios in the other one, one placenta and thin membrane between twins. The present study shows clinical course of 14 cases and value of Doppler ultrasound to analyze the usefulness of umbilical artery blood flow velocimetry for predicting the risk of twin-twin transfusion syndrome. 14 twin pregnancies with twin-twin transfusion syndrome were diagnosed during the last four years period and prospectivelly followed. 9 cases were diagnosed before the completion od 28 weeks of gestation.The mean gestational age was 21,6_+4,2 weeks at diagnosis and 23,2+_3,6 weeks at delivery. 5 cases were diagnosed after 28 weeks of gestation. The mean gestational age in this group was 29,6+_2,1 weeks at diagnosis and 33+_3,3 weeks at delivery. The survival rate in this study was 29%(8/28.9 cases ended in spontaneous abortion between 18th and 27th weeks of pregnancy (table 1 and 5 in premature labor (table 2.There were 7 intrauterine death (5 at admission and 2 few days after admission and 13 neonatal deaths

  4. Twin Higgs WIMP dark matter

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-01

    Dark matter (DM) without a matter asymmetry is studied in the context of twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) Z2 symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realization of the TH mechanism, the fraternal twin Higgs, with only a single generation of twin quarks and leptons, and the S U (3 )'×S U (2 )' gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the τ' lepton with a mass mτ'>mHiggs/2 , although spin-1 W'± DM and multicomponent DM are also possible (twin baryons are strongly disfavored by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom, Δ Neff . Direct detection signals are below current bounds but accessible in near-future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.

  5. Hydropic Placenta as a First Manifestation of Twin-Twin Transfusion in a Monochorionic Diamniotic Twin Pregnancy

    NARCIS (Netherlands)

    de Laat, Monique W. M.; Manten, Gwendoline T. R.; Nikkels, Peter G. J.; Stoutenbeek, Philip

    2009-01-01

    Monochorionic twin pregnancies are at a 10% to 1.5% risk of developing twin-twin transfusion syndrome (TTTS).(1) Monitoring such pregnancies is aimed at evaluating the fetal condition by measuring the amount of amniotic fluid, Doppler parameters, and fetal growth. Twin-twin transfusion syndrome may

  6. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  7. Reared-Apart Chinese Twins: Chance Discovery/Twin-Based Research: Twin Study of Media Use; Twin Relations Over the Life Span; Breast-Feeding Opposite-Sex Twins/Print and Online Media: Twins in Fashion; Second Twin Pair Born to Tennis Star; Twin Primes; Twin Pandas.

    Science.gov (United States)

    Segal, Nancy L

    2017-04-01

    A January 2017 reunion of 10-year-old reared-apart Chinese twin girls was captured live on ABC's morning talk show Good Morning America, and rebroadcast on their evening news program Nightline. The twins' similarities and differences, and their participation in ongoing research will be described. This story is followed by reviews of twin research concerning genetic and environmental influences on media use, twin relations across the lifespan and the breast-feeding of opposite-sex twins. Popular interest items include twins in fashion, the second twin pair born to an internationally renowned tennis star, twin primes and twin pandas.

  8. Intact twin tubal pregnancy

    Directory of Open Access Journals (Sweden)

    Nina Hodžić

    2010-08-01

    Full Text Available A case of a unilateral eight-week twin ectopic pregnancy diagnosed with transvaginal sonography is presented here. This ectopic pregnancy was found in the right Fallopian tube of a 35-year old woman. After the surgical procedure conducted by the method of transversal laparotomy, we removed the right Fallopian tube with two gestational sacs. So far only a hundred of such cases of ectopic twinpregnancy have been described worldwide.

  9. Acardiac twin pregnancies part III : Model simulations

    NARCIS (Netherlands)

    van Gemert, Martin J C; Ross, Michael G.; Nikkels, Peter G J; Wijngaard, Jeroen P H M van den

    2016-01-01

    Background: Acardiac monochorionic twins lack cardiac function but grow by passive perfusion of the pump twin's deoxygenated arterial blood through placental arterioarterial (AA) and venovenous (VV) anastomoses and by hypoxia-mediated neovascularization. Pump twins therefore must continuously

  10. Contemporary management of complicated monochorionic twins.

    Science.gov (United States)

    Moise, Karen Y; Kugler, Lisa; Jones, Tyra

    2012-01-01

    Monochorionic twins are at increased risk for unique complications including twin-twin transfusion syndrome (TTTS), selective intrauterine growth restriction (sIUGR), and twin-reversed arterial perfusion (TRAP) sequence. Twin-twin transfusion syndrome is treated with laser photocoagulation whereas selective reduction is an option in previable sIUGR or TRAP sequence. The nurse is integral in the management, education, care and support of women with complicated pregnancies. © 2012 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  11. Twinning across the Developing World.

    Directory of Open Access Journals (Sweden)

    Jeroen Smits

    Full Text Available BACKGROUND: Until now, little was known about the variation in incidence of twin births across developing countries, because national representative data was lacking. This study provides the first comprehensive overview of national twinning rates across the developing world on the basis of reliable survey data. METHODS: Data on incidence of twinning was extracted from birth histories of women aged 15-49 interviewed in 150 Demographic and Health Surveys, held between 1987 and 2010 in 75 low and middle income countries. During the interview, information on all live births experienced by the women was recorded, including whether it was a singleton or multiple birth. Information was available for 2.47 million births experienced by 1.38 million women in a period of ten years before the interview. Twinning incidence was measured as the number of twin births per thousand births. Data for China were computed on the basis of published figures from the 1990 census. Both natural and age-standardized twinning rates are presented. RESULTS/CONCLUSIONS: The very low natural twinning rates of 6-9 per thousand births previously observed in some East Asian countries turn out to be the dominant pattern in the whole South and South-East Asian region. Very high twinning rates of above 18 per thousand are not restricted to Nigeria (until now seen as the world's twinning champion but found in most Central-African countries. Twinning rates in Latin America turn out to be as low as those in Asia. Changes over time are small and not in a specific direction. SIGNIFICANCE: We provide the most complete and comparable overview of twinning rates across the developing world currently possible.

  12. Twin Legacies: Victor and Vincent McKusick/Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell-Silver Syndrome; Twins' Language Skills/Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Princess Ashraf (Twin); Yahoo CEO Delivers Identical Twins.

    Science.gov (United States)

    Segal, Nancy L

    2016-04-01

    The lives of the illustrious monozygotic (MZ) twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the 'Father of Medical Genetics', while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of twinning rates, a study of MZ twin discordance for Russell-Silver Syndrome (RSS) and a study of twins' language skills. Twin stories in the news include babies born to identical twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of twins who is also Yahoo's CEO.

  13. Twin classics: research that always inspires/Twin studies: elder twin relationships; Superfecundated twinning in chimpanzees; Conjoined twinning and embryo transfer; Reduced frequency of in vitro multiples/Professional and human interest: first identical twin renal transplant; Identical triplet wedding; Spanakos twins: boxers; Twins in space; Political twins.

    Science.gov (United States)

    Segal, Nancy L

    2015-08-01

    Ten classic works in twin research are described. These volumes are rich in data, interpretation, and impact, and contain life history material that adds depth and dimension to the quantitative findings. Next, research on social relationships in older twins, superfecundated twinning in chimpanzees; effects of embryo transfer on conjoined twinning and the reduced frequency of in vitro multiples is reviewed. Finally, there has been considerable public interest surrounding the first identical twin renal transplant, an identical triplet wedding; identical twin boxers, a twin living in space, and a politically active twin pair.

  14. Twin Peaks - 3D

    Science.gov (United States)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  15. Holographic twin Higgs model.

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  16. Oliver Sacks: Our Correspondence About Twins/Twin Research: Vanishing Twins Syndrome; Discordant Sex in MZ Twins; Pregnancy Outcomes in IVF and ICSI Conceived Twins/Print and Media: Superfetated Twins; Twins Discordant for Smoking; Twins in Fashion; Yale University Twin Hockey Players; Conjoined Twin-Visiting Professor.

    Science.gov (United States)

    Segal, Nancy L

    2017-08-01

    The late neurologist and author, Oliver Sacks, published an insightful 1986 review of Marjorie Wallace's book, The Silent Twins, in the New York Times. Taking exception to his assertion about Sir Francis Galton, I wrote a letter to the Times' editor. The letter was unpublished, but it brought a wonderful response from Sacks himself that is reproduced and examined. Next, brief reviews of twin research concerning the vanishing twin syndrome (VTS), discordant sex in a monozygotic (MZ) twin pair, and multiple pregnancy outcomes from assisted reproductive technology (ART) are presented. This section is followed by popular coverage of superfetated twins, smoking-discordant co-twins, twins in fashion, Yale University twin hockey players, and a visiting professor who was a conjoined twin.

  17. Hypertensive disorders in twin pregnancy

    NARCIS (Netherlands)

    J.G. Santema (Job); E. Koppelaar (Elin); H.C.S. Wallenburg (Henk)

    1995-01-01

    textabstractObjective: To compare the incidence and severity of pregnancy-induced hypertensive disorders in twin pregnancy and in singleton gestation. Study design: Case-control study in the setting of a University Hospital. Each pregnancy of a consecutive series of 187 twin pregnancies attending

  18. Socioeconomic position and twins' health

    DEFF Research Database (Denmark)

    Osler, Merete; McGue, Matt; Christensen, Kaare

    2007-01-01

    of middle-aged Danish twins was conducted in 1998-99. The study population included 1266 like-sex twin pairs [52.5% monozygotic (MZ) and 47.6% dizygotic (DZ)]. Data were obtained on childhood and adult social class and on height, BMI, grip strength, depression symptoms, self-rated health, cognitive function...... cognitive test scores. Among DZ female twins discordant on adult social class, the higher social class female twin was more physically active and had a higher cognitive test score. There were no significant health disparities or behavioural differences between the members of MZ twin pairs discordant......BACKGROUND: The association between socioeconomic circumstances and health in adulthood could come about through processes that may be divided into factors experienced early in life and those experienced in later adulthood. In order to disentangle the influences on health of the early genetic...

  19. Twin methodology in epigenetic studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob

    2015-01-01

    of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method...... to molecular phenotypes offers new opportunities to study the genetic (nature) and environmental (nurture) contributions to epigenetic regulation of gene activity during developmental, ageing and disease processes. Besides the classical twin model, the case co-twin design using identical twins discordant...... for a trait or disease is becoming a popular and powerful design for epigenome-wide association study in linking environmental exposure to differential epigenetic regulation and to disease status while controlling for individual genetic make-up. It can be expected that novel uses of twin methods in epigenetic...

  20. A Computational Discriminability Analysis on Twin Fingerprints

    Science.gov (United States)

    Liu, Yu; Srihari, Sargur N.

    Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

  1. Therapeutic modalities of twin to twin transfusion syndrome

    Directory of Open Access Journals (Sweden)

    Šulović N.

    2015-01-01

    Full Text Available Twin to twin transfusion syndrome (TTTTS accounts for approximately 10% of monochorionic twin pregnancies and, if left untreated, is associated with high morbidity and mortality rate. A net transfusion of blood flow from one fetus (donor twin to the other (recipient twin via placental vascular anastomoses has been supposed as the major etiology of TTTTS. The donor twin becomes hypovolemic and oliguria, oligohydramnios, and a variable degree of growth restriction develop, whereas the recipient twin manifests polyuria, polyhydramnios, and hydrops in response to hypervolemia. TTTTS can be treated by either serial amniocentesis or selective fetoscopic laser coagulation of the communicating vessels. The rationale for removal of large volumes of amniotic fluid is to prevent preterm delivery secondary to polyhydramnios and to improve fetal circulation by reducing pressure on the chorionic plate. On the other hand, the goal of laser therapy is to occlude vascular anastomoses, thereby interrupting intertwin blood exchange. Although laser treatment is associated with increased survival rate and reduced neurologic complications, compared with amnioreduction, it requires highly specialized centers, whereas serial amniocentesis has the advantage of being performed worldwide. Therefore, the optimal treatment for pregnancies complicated with TTTTS is still controversial.

  2. Estimating twin concordance for bivariate competing risks twin data

    DEFF Research Database (Denmark)

    Scheike, Thomas; Holst, Klaus K.; Hjelmborg, Jacob B.

    2014-01-01

    For twin time-to-event data, we consider different concordance probabilities, such as the casewise concordance that are routinely computed as a measure of the lifetime dependence/correlation for specific diseases. The concordance probability here is the probability that both twins have experienced...... over time, and covariates may be further influential on the marginal risk and dependence structure. We establish the estimators large sample properties and suggest various tests, for example, for inferring familial influence. The method is demonstrated and motivated by specific twin data on cancer...

  3. Twins and Kindergarten Separation: Divergent Beliefs of Principals, Teachers, Parents, and Twins

    Science.gov (United States)

    Gordon, Lynn Melby

    2015-01-01

    Should principals enforce mandatory separation of twins in kindergarten? Do school separation beliefs of principals differ from those of teachers, parents of twins, and twins themselves? This survey questioned 131 elementary principals, 54 kindergarten teachers, 201 parents of twins, and 112 twins. A majority of principals (71%) believed that…

  4. The nature of pseudo-twinning modes on the basis of a twin classification scheme

    International Nuclear Information System (INIS)

    Singh, Jung B.; Sundararaman, M.; Krishnan, M.

    2011-01-01

    Pseudo-twins can form in ordered structures under high stress conditions. These twins are defined by lattice sites that are at twin positions but are incorrectly occupied by different species of atoms. The present note discusses if it is possible to further classify pseudo-twins into different modes based on the nature of associated twinning elements.

  5. Successful separation of Xipho-Omphalopagus twins

    Directory of Open Access Journals (Sweden)

    Oak S

    2007-01-01

    Full Text Available Xipho-omphalopagus twins are conjoined twins sharing some part of gastrointestinal system and lower sternum. These types of twins have best chances of survival if successfully separated. We report a case of successfully separated Xipho-omphalopagus twins, highlighting the importance of proper planning and team effort in such separations.

  6. Monochorionic twin pregnancies: a systematic approach to ...

    African Journals Online (AJOL)

    Complications unique to these pregnancies include Twin-To-Twin Transfusion Syndrome (TTTS), Twin Polycythaemia Anaemia Sequence (TAPS), Selective Intrauterine Growth Restriction (sIUGR) and death of the co-twin. Adhering to a systematic and objective approach of management, can lead to early recognition and ...

  7. Fivefold twinned boron carbide nanowires.

    Science.gov (United States)

    Fu, Xin; Jiang, Jun; Liu, Chao; Yuan, Jun

    2009-09-09

    Chemical composition and crystal structure of fivefold twinned boron carbide nanowires have been determined by electron energy-loss spectroscopy and electron diffraction. The fivefold cyclic twinning relationship is confirmed by systematic axial rotation electron diffraction. Detailed chemical analysis reveals a carbon-rich boron carbide phase. Such boron carbide nanowires are potentially interesting because of their intrinsic hardness and high temperature thermoelectric property. Together with other boron-rich compounds, they may form a set of multiply twinned nanowire systems where the misfit strain could be continuously tuned to influence their mechanical properties.

  8. Advanced methods in twin studies.

    Science.gov (United States)

    Kaprio, Jaakko; Silventoinen, Karri

    2011-01-01

    While twin studies have been used to estimate the heritability of different traits and disorders since the beginning of the twentieth century, statistical developments over the past 20 years and more extensive and systematic data collection have greatly expanded the scope of twin studies. This chapter reviews selected possibilities of twin study designs to address specific hypotheses regarding the role of both genetic and environmental factors in the development of traits and diseases. In addition to modelling latent genetic influences, current models permit inclusion of information on specific genetic variants, measured environmental factors and their interactive effects. Examples from studies of anthropometric traits are used to illustrate such approaches.

  9. Twin-to-twin transfusion syndrome : from placental anastomoses to long-term outcome

    NARCIS (Netherlands)

    Lopriore, Enrico

    2006-01-01

    Twin-to-twin transfusion syndrome (TTTS) is a severe complication of monochorionic twin pregnancies associated with high perinatal mortality and morbidity rates. Placental vascular anastomoses, almost invariably present in monochorionic placentas, are the essential anatomical substrate for the

  10. Infertility, infertility treatment and twinning

    DEFF Research Database (Denmark)

    Zhu, Jin Liang; Basso, Olga; Obel, Carsten

    2007-01-01

    BACKGROUND: We have previously observed that an increasing time to pregnancy (TTP) is associated with a reduced frequency of twin deliveries in couples not receiving infertility treatment. By using updated information, we assessed the frequencies of dizygotic (DZ) and monozygotic (MZ) twin...... deliveries as a function of infertility (TTP > 12 months), as well as infertility treatment. METHODS: From the Danish National Birth Cohort (1997-2003), we identified 51 730 fertile couples with TTP 12 months and 5163 infertile couples who conceived after treatment. Information on zygosity, available...... for part of the cohort (1997-2000), was based on standardized questions on the similarities between the twins at the age of 3-5 years. RESULTS: Compared with fertile couples, the frequency of DZ twin deliveries was lower for infertile couples conceiving naturally (odds ratio 0.4, 95% confidence interval 0...

  11. A Powerful Twin Arrives

    Science.gov (United States)

    1999-11-01

    First Images from FORS2 at VLT KUEYEN on Paranal The first, major astronomical instrument to be installed at the ESO Very Large Telescope (VLT) was FORS1 ( FO cal R educer and S pectrograph) in September 1998. Immediately after being attached to the Cassegrain focus of the first 8.2-m Unit Telescope, ANTU , it produced a series of spectacular images, cf. ESO PR 14/98. Many important observations have since been made with this outstanding facility. Now FORS2 , its powerful twin, has been installed at the second VLT Unit Telescope, KUEYEN . It is the fourth major instrument at the VLT after FORS1 , ISAAC and UVES.. The FORS2 Commissioning Team that is busy installing and testing this large and complex instrument reports that "First Light" was successfully achieved already on October 29, 1999, only two days after FORS2 was first mounted at the Cassegrain focus. Since then, various observation modes have been carefully tested, including normal and high-resolution imaging, echelle and multi-object spectroscopy, as well as fast photometry with millisecond time resolution. A number of fine images were obtained during this work, some of which are made available with the present Press Release. The FORS instruments ESO PR Photo 40a/99 ESO PR Photo 40a/99 [Preview - JPEG: 400 x 345 pix - 203k] [Normal - JPEG: 800 x 689 pix - 563kb] [Full-Res - JPEG: 1280 x 1103 pix - 666kb] Caption to PR Photo 40a/99: This digital photo shows the twin instruments, FORS2 at KUEYEN (in the foreground) and FORS1 at ANTU, seen in the background through the open ventilation doors in the two telescope enclosures. Although they look alike, the two instruments have specific functions, as described in the text. FORS1 and FORS2 are the products of one of the most thorough and advanced technological studies ever made of a ground-based astronomical instrument. They have been specifically designed to investigate the faintest and most remote objects in the universe. They are "multi-mode instruments" that

  12. Sunset over Twin Peaks

    Science.gov (United States)

    1997-01-01

    This image was taken by the Imager for Mars Pathfinder (IMP) about one minute after sunset on Mars on Sol 21. The prominent hills dubbed 'Twin Peaks' form a dark silhouette at the horizon, while the setting sun casts a pink glow over the darkening sky. The image was taken as part of a twilight study which indicates how the brightness of the sky fades with time after sunset. Scientists found that the sky stays bright for up to two hours after sunset, indicating that Martian dust extends very high into the atmosphere.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  13. Spina bifida occulta and monozygotic twins.

    Science.gov (United States)

    Spacca, Barbara; Buxton, Neil

    2008-10-01

    Central nervous system maldevelopment can have different presentations in twins. We report on a case of different presentations of spina bifida occulta in monozygotic twins. The first twin presented at birth with a lipomyelomeningocele; a tethered cord was diagnosed in the second twin at 2 years of age. Neural tube defects (NTDs) are a group of common congenital malformations of the brain and spine generated during neurulation. The genetic basis of this process is still not well known. Whenever an NTD is diagnosed in one of a pair of twins, the other twin should also be evaluated for NTDs.

  14. [Twin dystocia: about one case of compaction].

    Science.gov (United States)

    Desseauve, D; Voluménie, J-L

    2008-09-01

    We report a case of twin dystocia during the evacuation of full-term fetus both in cephalic presentation. A low-outlet forceps for second-phase arrest was performed for the first twin but the head remained stuck to maternal perineum, mimicking a shoulder dystocia. Digital examination found a twin compaction, that is the presence of the second twin's fetal head at the level of the first twin's chest. The discrepancy between fetal weights and the use of forceps could favor this rare complication. Various maneuvers were described previously attempted to solve the problem. Forcing back the second head may help to achieve delivery of the first twin.

  15. Growth curves for twins in Slovenia.

    Science.gov (United States)

    Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša

    2017-02-01

    Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.

  16. Twin-twin transfusion syndrome: neurodevelopmental screening test

    Directory of Open Access Journals (Sweden)

    Amabile Vessoni Arias

    2015-03-01

    Full Text Available Objective To assess the neurodevelopmental functions (cognition, language and motor function of survivors of twin-twin transfusion syndrome (TTTS. Method Observational cross-sectional study of a total of 67 monochorionic diamniotic twins who underwent fetoscopic laser coagulation (FLC for treatment of TTTS. The study was conducted at the Center for Investigation in Pediatrics (CIPED, Universidade Estadual de Campinas. Ages ranged from one month and four days to two years four months. Bayley Scales of Infant and Toddler Development Screening Test-III, were used for evaluation. Results Most children reached the competent category and were classified as having appropriate performance. The preterm children scored worse than term infants for gross motor subtest (p = 0.036. Conclusion The majority of children reached the expected development according to their age. Despite the good neurodevelopment, children classified at risk should be monitored for development throughout childhood.

  17. Complications Arising in Twin Pregnancy: Findings of Prenatal Ultrasonography

    Science.gov (United States)

    Kim, Jeong-Ah; Lee, Young Ho; Song, Mi Jin; Min, Jee-Yeon; Lee, Hak Jong; Han, Byoung Hee; Lee, Kyung-Sang; Cho, Byung Jae; Chun, Yi-Kyeong

    2003-01-01

    Multifetal gestations are high-risk pregnancies involving higher perinatal morbidity and mortality, and are subject to unique complications including twin oligohydramnios-polyhydramnios sequence, twin-to-twin transfusion syndrome, acardiac twins, conjoined twins, co-twin demise, and heterotopic pregnancies. The purpose of this study is to describe the prenatal ultrasonographic and pathologic findings of these complications. PMID:12679635

  18. Risk of Oral Clefts in Twins

    DEFF Research Database (Denmark)

    Grosen, Dorthe; Bille, Camilla; Petersen, Inge

    2011-01-01

    BACKGROUND:: Small studies have indicated that twinning increases the risk of oral cleft. METHODS:: We used data from a Danish national population-based cohort study to investigate whether twinning was associated with isolated oral cleft, and to estimate the twin probandwise concordance rate...... and heritability. Twins (207 affected/130,710) and singletons (7766 affected/4,798,526) born from 1936 through 2004 in Denmark were ascertained by linkage among the Danish Facial Cleft Database, the Danish Twin Registry, and the Civil Registration System. We computed oral cleft prevalence and prevalence proportion...... ratio for twins versus singletons, stratified for 3 subphenotypes. Probandwise concordance rates and heritability for twins were estimated for 2 phenotypes-cleft lip with or without cleft palate (CL/P) and cleft palate (CP). RESULTS:: The prevalence of oral cleft was 15.8 per 10,000 twins and 16.6 per...

  19. Nike Twins Seven Seven: Nigerian Batik Artist.

    Science.gov (United States)

    LaDuke, Betty

    1987-01-01

    Chronicles the personal and professional life of Nike Twins Seven Seven (born 1951), a Nigerian batik artist, and her husband, Twins Seven Seven, a musician-artist, both of whom have received international acclaim. (BJV)

  20. Preterm twin gestation and cystic periventricular leucomalacia

    NARCIS (Netherlands)

    Resch, B; Jammernegg, A; Vollaard, E; Maurer, U; Mueller, WD; Pertl, B

    Objective: To identify risk factors for the development of cystic periventricular leucomalacia (PVL) in twin gestation. Design: Retrospective case-control study. Setting: Tertiary care university hospital, Department of Paediatrics, Division of Neonatology, Graz, Austria. Patients: Preterm twin

  1. Congenital diaphragmatic hernia in identical twins

    Directory of Open Access Journals (Sweden)

    Mustafa T Gurbaz

    2012-01-01

    Full Text Available Congenital diaphragmatic hernia (CDH, Bochdalek type is rarely seen in both members of identical twins. Herein, we report a 37 weeks′ twins with CDH along with a brief review of the literature. Both the neonates survived.

  2. Significance of donor anuria differs between monoamniotic and diamniotic twin-twin transfusion syndrome

    NARCIS (Netherlands)

    Schaap, A. H. P.; van den Wijngaard, J. P. H. M.; Nikkels, P. G. J.; van den Broek, A. J. M.; Snieders, I.; van Gemert, M. J. C.

    2007-01-01

    Development of severe twin-twin transfusion syndrome (TTTS) in diamniotic-monochorionic twins includes five stages of increasing severity, i.e. recipient polyhydramnios and donor oligohydramnios, donor anuria, abnormal umbilical flow velocities in either twin, hydrops in the recipient, and

  3. Twin and triple peaks papilledema.

    Science.gov (United States)

    Mehta, Jodhbir S; Plant, Gordon T; Acheson, James F

    2005-07-01

    To describe 2 adult patients who presented with papilledema after band atrophy (i.e., twin and triple peaks papilledema). Retrospective small case series. Two outpatients. Observations made on 2 patients whose cases were reviewed in the neuro-ophthalmology clinic. The first patient had a pituitary tumor presenting with papilledema, causing a triple peaks clinical sign. Color photographs, optical coherence tomograms, and magnetic resonance images are shown. The second patient developed twin peaks papilledema due to a chiasmal glioma causing secondary raised intracranial pressure. Twin peaks papilledema is a rare clinical sign that may develop in adults as well as in children. The first report and optical coherence tomography features of triple peaks papilledema illustrate a new clinical sign.

  4. Twins or two single children

    Directory of Open Access Journals (Sweden)

    2002-08-01

    Full Text Available Based on Swedish register data, we compared the influence of a twin birth on the divorce risk with the influence of the sequential birth of two single children. The divorce risk for a woman with a very young child was lower than the risk for women without children or women with children older than 3.5 years. This behaviour was essentially independent of the number of children and whether or not the woman gave birth to twins. The effect of parity was much smaller than the effect of child age. The influence of twins on the divorce risk appeared to fall between that of a first and a second singleton.

  5. The Fourth International Network of Twin Registries: Overview from Osaka/Research Reviews: Familial Fraternal Twinning; Twin Study of Masculine Faces; Physical Aggression and Epigenetics; Prenatal Education for Parents of Twins/Current Events: 2016 Guinness Book of World Records; Oldest Living Male Twins; Twins Reunited at Sixty-Nine; Panda Twins; Twins.com.

    Science.gov (United States)

    Segal, Nancy L

    2015-12-01

    The 4th International Network of Twin Registries (INTR) Consortium Meeting took place in Osaka, Japan, September 28-29, 2015. The venue was the Osaka Medical Center for Medical Innovation and Translational Research. An overview of presentations and other activities is provided. Next, 1930s research on familial fraternal twinning, preference for masculine faces, physical aggression and epigenetics, and a prenatal education program for parents of multiples are described. Current twin-related events include the 2016 Guinness Book of World Records (GWR), the oldest living male twins, newly reunited twins, the birth of panda twins and a controversial twin-based website.

  6. Fatique life and twinning in alphazirconium

    DEFF Research Database (Denmark)

    Warren, M.R.; Beevers, C.J.

    1970-01-01

    −21}, and {11•22} twins and {1O−10} slip. In grains completely enclosed by surrounding material fatigue damage has been found in association with 11•21 twins and very occasionally with {11−22} twins but not with 10•12 twins. A further quantitative interpretation has shown that there is a critical resolved shear...... direction. Formerly with the Department of Physical Metallurgy and Science of Materials, The University, Birmingham, England...

  7. Remembering Irving I. Gottesman: Twin Research Colleague and Friend Extraordinaire/Research Studies: Face-Lift Technique Comparison in Identical Twins; Raising Preterm Twins; Fetal Behavior in Dichorionic Twin Pregnancies; Co-Bedding and Stress Reduction in Twins/Public Interest: Identical Co-Twins' Same Day Delivery; Teaching Twins in Bosnia; Twin Auctioneers; Sister, the Play.

    Science.gov (United States)

    Segal, Nancy L

    2016-12-01

    Dr Irving I. Gottesman, a colleague, friend, and long-time member of the International Society of Twin Studies passed away on June 29, 2016. His contributions to twin research and some personal reflections are presented to honor both the man and the memory. This tribute is followed by short reviews of twin research concerning differences between cosmetic surgical techniques, the rearing of preterm twins, behavioral observations of dichorionic fetal twins, and the outcomes of co-bedding twins with reference to stress reduction. Interesting and informative articles in the media describe identical co-twins who delivered infants on the same day, educational policies regarding twins in Bosnia and the United Kingdom, unusual practices of twin auctioneers, and a theatrical production, Sister, featuring identical twins in the leading roles.

  8. Twins or two single children

    OpenAIRE

    Rainer Walke

    2002-01-01

    Based on Swedish register data, we compared the influence of a twin birth on the divorce risk with the influence of the sequential birth of two single children. The divorce risk for a woman with a very young child was lower than the risk for women without children or women with children older than 3.5 years. This behaviour was essentially independent of the number of children and whether or not the woman gave birth to twins. The effect of parity was much smaller than the effect of child age. ...

  9. Concordance for multiple sclerosis in Danish twins

    DEFF Research Database (Denmark)

    Hansen, T; Skytthe, Axel; Stenager, Egon

    2005-01-01

    The occurrence of multiple sclerosis (MS) in twins has not previously been studied in complete nationwide data sets. The existence of almost complete MS and twin registries in Denmark ensures that essentially unbiased samples of MS cases among twins can be obtained. In this population-based study...

  10. First-trimester diagnosis of conjoined twins

    NARCIS (Netherlands)

    Pajkrt, Eva; Jauniaux, Eric

    2005-01-01

    Conjoined twins are a rare and complex complication of monozygotic twinning, which is associated with high perinatal mortality. Early prenatal diagnosis of conjoined twins allows better counselling of the parents regarding the management options, including continuation of pregnancy with post-natal

  11. Protease inhibitor (Pi) locus, fertility and twinning

    NARCIS (Netherlands)

    Boomsma, D.I.; Frants, R.R.; Bank, R.A.; Martin, N.G.

    1992-01-01

    In a sample of 160 Dutch twin pairs and their parents, we found that mothers of dizygotic twins had frequencies of the S and Z alleles at the protease inhibitor (Pi) locus that were 3 times higher than a control sample. Mothers of identical twins also had a higher frequency of S than controls. The S

  12. A study of malocclusion in identical twins

    Directory of Open Access Journals (Sweden)

    E. Akhavan Niaki

    1998-04-01

    Full Text Available   Monozygotic twins are genetically identical individuals who can also be mirror image twins and the Differences between them result from environmental factors. current study, monozygotic twins were analyzed in different dentitions of primary, mixed and permanent. As a conclusion, although genetic factors are naturally potent, environmental factors’ role can be increased and weaken the genetic factors.

  13. Epigenetic Epidemiology of Complex Diseases Using Twins

    DEFF Research Database (Denmark)

    Tan, Qihua

    2013-01-01

    through multiple epigenetic mechanisms. This paper reviews the new developments in using twins to study disease-related epigenetic alterations, links them to lifetime environmental exposure with a focus on the discordant twin design and proposes novel data-analytical approaches with the aim of promoting...... a more efficient use of twins in epigenetic studies of complex human diseases....

  14. Sports pairs: insights on athletic talent; research reviews: twins with leukemia; parents and twins.

    Science.gov (United States)

    Segal, Nancy L

    2007-06-01

    Twin research exploring genetic and environmental influences on athletic interests and talents is reviewed. Illustrative examples of twin athletes representing a variety of sports activities are presented. This is followed by an overview of twin studies offering critical insights into the onset and progress of leukemia. In the last section, timely events involving twins and parents of twins will be described--each case provides a new look at an old question.

  15. Four twins for a paradox: on "sensitive" twins and the biological counterpart of the "twin paradox".

    Science.gov (United States)

    Ascioti, Fortunato A

    2009-03-01

    Monozygotic twin (MZT) epigenetic development, i.e., aging, diverges largely in time despite the initially very small genetic differences between MZTs. This fact is interpreted as a "sensitivity to initial conditions" phenomenon, a common property of either deterministic or stochastic chaotic systems. Some of the biotheoretical implications stemming from this empirical observation are briefly discussed here, while an actual measure of MZT epigenetic time divergence is given through an estimate of the (Stochastic) Lyapunov exponents (LEs) (i.e., the rate of exponential time divergence). These results suggest a reconsideration of the Langevin-Einstein thought experiment known as the "twin paradox." At least four twins are necessary in order to take into account the inertially independent divergent aging described here. Alternatively, LE estimates, like those given here, should be used. Finally suggested in the actual special-relativity experiments is the replacement of clocks with some nonlinear (chaotic) forced oscillator.

  16. Similarity of social security numbers among twins: data from the Virginia Twin Registry.

    Science.gov (United States)

    Page, W F; Corey, L

    1998-09-01

    At least two twin registries in the United States have been or are being assembled using the similarity of Social Security Numbers in computerized records to help identify possible twin pairs. While the success of such enterprises depends directly on a high probability of twinness given Social Security Numbers, there are theoretical and practical reasons to study the probability of Social Security Number similarity given twinness. For example, the number of twin pairs with similar Social Security Numbers obviously determines the maximum number of twin pairs that can be discovered by similarity algorithms. To study this issue, we examined the similarity of known Social Security Numbers in twin pairs from the Virginia Twin Registry by age, sex, race, and zygosity of the pair. We found that similarity between the Social Security Numbers of twin pairs varies markedly by age, and MZ twin pairs have significantly more similar Social Security Numbers than DZ pairs at all ages. Among older twins, there are also significant differences by sex and race. For younger twins, algorithms that identify putative twin pairs on the basis of the similarity of their Social Security Numbers hold the promise of being able to identify a large proportion of all true twin pairs. Such algorithms will be substantially less successful, however, in identifying a large proportion of older twin pairs.

  17. Elizabeth M. Bryan: tributes from home and abroad; research reviews: anorexia nervosa in opposite-sex twins, twin study of self-esteem, DNA differences in monozygotic twins; twins and more twins: twins living apart, twins playing together, twins working together, twins playing apart, multiple birth odds.

    Science.gov (United States)

    Segal, Nancy L

    2008-06-01

    Elizabeth M. Bryan: Tributes From Home and Abroad May 13, 1942 - February 21, 2008 The life and work of Dr Elizabeth M. Bryan, our late distinguished twin studies colleague, are remembered. Tributes come from colleagues in the United States and the United Kingdom, where Elizabeth lived and worked. This section is followed by reviews of twin research on anorexia nervosa, self-esteem and DNA differences in monozygotic twins. The lives of some noteworthy twins are also briefly chronicled, both for their scientific value and human interest. An update on current twinning rates follows.

  18. Twin Peaks (B/W)

    Science.gov (United States)

    1997-01-01

    The Twin Peaks are modest-size hills to the southwest of the Mars Pathfinder landing site. They were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997, and subsequently identified in Viking Orbiter images taken over 20 years ago. The peaks are approximately 30-35 meters (-100 feet) tall. North Twin is approximately 860 meters (2800 feet) from the lander, and South Twin is about a kilometer away (3300 feet). The scene includes bouldery ridges and swales or 'hummocks' of flood debris that range from a few tens of meters away from the lander to the distance of the South Twin Peak. The large rock at the right edge of the scene is nicknamed 'Hippo'. This rock is about a meter (3 feet) across and 25 meters (80 feet) distant.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  19. Digital twins in farm management

    NARCIS (Netherlands)

    Verdouw, C.N.; Kruize, J.W.

    2017-01-01

    The Internet of Things (IoT) provides a vision of a world in which the Internet extends into the real world embracing everyday objects. In the IoT, physical objects are accompanied by Digital Twins: virtual, digital equivalents to physical objects. The interaction between real/physical and

  20. Comparison intercuspal mandible position twins

    Directory of Open Access Journals (Sweden)

    Kučević Esad

    2015-01-01

    Full Text Available The twins are the miracle of fetal biology, medical reproductive challenge, the closest and most durable biological connection. The aim is to identify, evaluate and compare the type, number and location interjaw functional contacts in the intercuspal position of the mandible, with MZ monozygotic (identical twins. Analysis of occlusal relationships in the most stable-intercuspal comparison was done on a sample of 60 identical twins, by 15 female and 15 male pairs, chronological ages 18 to 40, in which the means of articulation papers specific localization and distribution of contact relationships, in the region of the lateral teeth. Results of this study showed that in the lateral region, 57 respondents or 95%, has the modalities of occlusal relationships lump-ridges-marginal edge. Average more occlusal contacts identified in males (25.1 than in female twin pairs (19.1. Also, in male couples registered more three points (M: F = 7: 1, two points by gender is equal 24:12, and contacts at one point they outnumber men (22, compared to female respondents (18. Less Similarities than expected sameness, proving that the number, distribution and intensity of occlusal contacts in the mandible vary individually.

  1. Tuberous Sclerosis in Identical Twins

    Directory of Open Access Journals (Sweden)

    Dinesh C Govil

    1987-01-01

    Full Text Available Tuberous sclerosis was, observed in six year old identical twin brothers born with single placenta and a single amnion. Both had adenoma sebaceum shagreen patches, ash leaf spots and progressive mental deterioration. One of them had a verrucous pigmented nevus on the, left temple and recurrent localized motor seizures.

  2. Fetal growth disorders in twin gestations.

    LENUS (Irish Health Repository)

    Breathnach, Fionnuala M

    2012-06-01

    Twin growth is frequently mismatched. This review serves to explore the pathophysiologic mechanisms that underlie growth aberrations in twin gestations, the prenatal recognition of abnormal twin growth, and the critical importance of stratifying management of abnormal twin growth by chorionicity. Although poor in utero growth of both twins may reflect maternal factors resulting in global uteroplacental dysfunction, discordant twin growth may be attributed to differences in genetic potential between co-twins, placental dysfunction confined to one placenta only, or one placental territory within a shared placenta. In addition, twin-twin transfusion syndrome represents a distinct entity of which discordant growth is a common feature. Discordant growth is recognized as an independent risk factor for adverse perinatal outcome. Intertwin birth weight disparity of 18% or more should be considered to represent a discordance threshold, which serves as an independent risk factor for adverse perinatal outcome. At this cutoff, perinatal morbidity is found to increase both for the larger and the smaller twin within a discordant pair. There remains uncertainty surrounding the sonographic parameters that are most predictive of discordance. Although heightening of fetal surveillance in the face of discordant twin growth follows the principles applied to singleton gestations complicated by fetal growth restriction, the timing of intervention is largely influenced by chorionicity.

  3. Register-based research on twins

    DEFF Research Database (Denmark)

    Christensen, Kaare; Ohm Kyvik, Kirsten; Holm, Niels V

    2011-01-01

    Introduction: The Danish Twin Registry (DTR) has for more than 50 years been based on surveys and clinical investigations and over the two last decades also on register linkage. Currently these two approaches are merged within Statistics Denmark. Research topics: Here we report on three major...... groups of register-based research in the DTR that used the uniqueness of twinning. First, we focus on the ''long-term prognosis'' of being a twin compared with being a singleton and show that Danish twins have health trajectories in adulthood similar to singletons, which is a result of interest for twins...... illustrate how the co-twin control method in a register setting can be used to control for the effect of rearing environment and genetic factors in studies of the association between exposures and health. CONCLUSION: The spectrum of register-based twin studies is very wide and have changed in accordance...

  4. Is that me or my twin? Lack of self-face recognition advantage in identical twins.

    Directory of Open Access Journals (Sweden)

    Matteo Martini

    Full Text Available Despite the increasing interest in twin studies and the stunning amount of research on face recognition, the ability of adult identical twins to discriminate their own faces from those of their co-twins has been scarcely investigated. One's own face is the most distinctive feature of the bodily self, and people typically show a clear advantage in recognizing their own face even more than other very familiar identities. Given the very high level of resemblance of their faces, monozygotic twins represent a unique model for exploring self-face processing. Herein we examined the ability of monozygotic twins to distinguish their own face from the face of their co-twin and of a highly familiar individual. Results show that twins equally recognize their own face and their twin's face. This lack of self-face advantage was negatively predicted by how much they felt physically similar to their co-twin and by their anxious or avoidant attachment style. We speculate that in monozygotic twins, the visual representation of the self-face overlaps with that of the co-twin. Thus, to distinguish the self from the co-twin, monozygotic twins have to rely much more than control participants on the multisensory integration processes upon which the sense of bodily self is based. Moreover, in keeping with the notion that attachment style influences perception of self and significant others, we propose that the observed self/co-twin confusion may depend upon insecure attachment.

  5. Keratoconus in 18 pairs of twins.

    Science.gov (United States)

    Tuft, Stephen J; Hassan, Hala; George, Sonia; Frazer, David G; Willoughby, Colin E; Liskova, Petra

    2012-09-01

    To describe the concordance of keratoconus in 18 sets of twins. Thirteen monozygotic (MZ) and five dizygotic (DZ) pairs of twins were identified during an investigation of familial keratoconus. We used 16 forensic microsatellite markers to confirm the zygosity of same sex twins. Patients and available relatives were examined for signs of keratoconus using corneal topography. For each pair of twins, the severity of keratoconus in each eye was graded according to the steepest keratometry value and the average difference in score between the MZ and DZ twins compared. All of the MZ twins and four of the five DZ twins were concordant for keratoconus but with differences in age of onset and severity of disease. The subjective age of onset of keratoconus tended to be earlier in the MZ twins (16.4 years, SD 4.66) than in the DZ twins (20.3 years, SD 7.55) (p=0.086). Additional relatives with keratoconus were identified in two (16%) of the families with MZ twins and in three (60%) of the families of DZ twins. The mean difference in severity scores was 1.4 (SD 1.73) for the MZ twins and 3.0 (SD 1.00) for the DZ twins (p=0.035). This data provide evidence that the severity of keratoconus is more concordant in MZ than in DZ twins. The results support the currently accepted hypothesis of an important genetic contribution towards the pathogenesis of keratoconus, but suggest that there is also an environmental effect on the expression of disease. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  6. Social Comparison Orientation in Monozygotic and Dizygotic Twins.

    Science.gov (United States)

    Huguet, Pascal; Carlier, Michèle; Dolan, Conor V; de Geus, Eco J; Boomsma, Dorret I

    2017-12-01

    Twin research has offered evidence that monozygotic (MZ) twins are more socially close than dizygotic (DZ) twins, but has not paid much attention to the way twins compare themselves with their co-twin. The few studies in this area suggest that 'horizontal comparisons' (social comparison motivated by solidarity or communion with others) matter more for MZ twins than for DZ twins, at least when the co-twin is the social comparison standard. Consistent with this view, we predicted higher interest in MZ twins relative to DZ twins to select their co-twin rather than other people in general as the social comparison standard. The Social Comparison Orientation (SCO) scale, which measures the inclination to compare with others in a horizontal rather than vertical mode (comparing either upward or downward), was administered in 90 MZ pairs and 57 same-sex DZ pairs (63% female; average age 18.06 years) from the Netherlands Twin Register. MZ twin pairs showed significantly higher SCO scores than DZ twin pairs (with a large effect size) on the co-twin SCO, whereas the two groups did not differ from each other on the general SCO excluding the co-twin as social comparison standard. In MZ twin pairs, anxiety was associated with social comparison with others in general, not with their co-twin. For both scales, twin resemblance was explained by additive genetic variance. The present findings provide direct evidence that horizontal comparisons with the co-twin are of particular importance for MZ twins.

  7. Fingerprint recognition with identical twin fingerprints.

    Science.gov (United States)

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  8. Fingerprint recognition with identical twin fingerprints.

    Directory of Open Access Journals (Sweden)

    Xunqiang Tao

    Full Text Available Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6 images. Compared to the previous work, our contributions are summarized as follows: (1 Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2 Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3 A larger sample (83 pairs was collected. (4 A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5 A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  9. Emergency separation of a xipho-omphalopagus twin in a ...

    African Journals Online (AJOL)

    Female conjoined twins (thoraco-omphalopagus) were delivered by emergency caesarean section in a private nursing home. On examination, one of the twins was dead and was threatening the survival of the surviving twin (twin A). An emergency separation was performed to salvage the surviving twin.

  10. Conjoined omphalopagus twins: a casereport

    Directory of Open Access Journals (Sweden)

    Sheila Yadira Gómez-Murillo

    2014-11-01

    Full Text Available Multiple pregnancies are 3% of the total. The most frequent are dizygotic females, however, a small group of them are of monozygotic conjoined twins in some anatomical area. This attracts the attention of physicians because of the rarity of the condition and the difficulties as well as the ethical dilemmas for their treatment. We report a case of male Siamese omphalopagus. They were separated surgically at seven weeks of age. One of them lived six months.

  11. Identical twins in forensic genetics

    DEFF Research Database (Denmark)

    Tvedebrink, Torben; Morling, Niels

    2015-01-01

    The increase in the number of forensic genetic loci used for identification purposes results in infinitesimal random match probabilities. These probabilities are computed under assumptions made for rather simple population genetic models. Often, the forensic expert reports likelihood ratios, where...... published results accounting for close familial relationships. However, we revisit the discussion to increase the awareness among forensic genetic practitioners and include new information on medical and societal factors to assess the risk of not considering a monozygotic twin as the true perpetrator...

  12. Ectodermal dysplasia in identical twins

    OpenAIRE

    Puttaraju, Gurkar Haraswarupa; Visveswariah, Paranjyothi Magadi

    2013-01-01

    Hereditary hypohidrotic ectodermal dysplasia (HED) is typically inherited as an X-linked recessive trait, characterized by deformity of at least two or more of the ectodermal structures - hair, teeth, nails and sweat glands. Two cases of hereditary HED involving identical male twins, is being documented for the rarity of its occurrence with special attention given to genetics, pathophysiology, clinical, intraoral manifestations and to the methods to improve the masticatory function, the facia...

  13. Twinning of Polymer Crystals Suppressed by Entropy

    Directory of Open Access Journals (Sweden)

    Nikos Ch. Karayiannis

    2014-09-01

    Full Text Available We propose an entropic argument as partial explanation of the observed scarcity of twinned structures in crystalline samples of synthetic organic polymeric materials. Polymeric molecules possess a much larger number of conformational degrees of freedom than low molecular weight substances. The preferred conformations of polymer chains in the bulk of a single crystal are often incompatible with the conformations imposed by the symmetry of a growth twin, both at the composition surfaces and in the twin axis. We calculate the differences in conformational entropy between chains in single crystals and chains in twinned crystals, and find that the reduction in chain conformational entropy in the twin is sufficient to make the single crystal the stable thermodynamic phase. The formation of cyclic twins in molecular dynamics simulations of chains of hard spheres must thus be attributed to kinetic factors. In more realistic polymers this entropic contribution to the free energy can be canceled or dominated by nonbonded and torsional energetics.

  14. Evolution equations of deformation twins in metals-Evolution of deformation twins in pure titanium

    International Nuclear Information System (INIS)

    Cai Shengqiang; Li Ziran; Xia Yuanming

    2008-01-01

    The evolution equations of the volume fractions of deformation twins are obtained in this article by using the theory of inclusions in micromechanics and analyzing the Gibbs free energy and dissipation of a system. The evolution process of the volume fractions of twins is got by using the Runge-Kutta method in this article. The computational results of the evolution equations (the critical twinning stress and the families of twins appeared under different loading conditions) are consistent with the experiment results

  15. Exotic quarks in Twin Higgs models

    Science.gov (United States)

    Cheng, Hsin-Chia; Jung, Sunghoon; Salvioni, Ennio; Tsai, Yuhsin

    2016-03-01

    The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ˜ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of the model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. Depending on the details of the twin sector, the exotic quarks may be probed up to ˜ 2.5TeV at the LHC and beyond 10TeV at a future 100TeV collider, providing a strong test of this class of ultraviolet completions.

  16. Anaesthesia for the separation of conjoined twins

    Directory of Open Access Journals (Sweden)

    Jaya Lalwani

    2011-01-01

    Full Text Available Thoraco-omphalopagus is one of the most common type of conjoint twins accounting for 74% cases of conjoint twins. We report the anaesthetic management for successful separation of thoraco-omphalopagus conjoint twins, both of them surviving till date. We highlight the responsibility of anaesthesia team in anaesthetising the two individual patients simultaneously, need of careful monitoring and anticipation of complications like massive blood loss, hypotension, hypokalemia, hypoxia and hypercabia. Detailed description of successful management is reported.

  17. Dynamics of twin boundaries in martensites

    Energy Technology Data Exchange (ETDEWEB)

    Barsch, G.R.; Horovitz, B.; Krumhansl, J.A.

    1987-09-14

    The theory of forming a coherent twinning array in a parent phase is studied for a tetragonal to orthorhombic displacive transition. We find that this structure can be stabilized without the use of dislocations by a long-range interaction between the twin boundaries which is mediated via the parent phase. The dynamics of the twin boundary lattice consists of elementary excitations with surprisingly low frequency and a limiting -- (wave vector)/sup 1/2/ dispersion.

  18. Higher Incidence of Hypospadias in Monochorionic Twins.

    Science.gov (United States)

    Visser, Remco; Burger, Nienke C M; van Zwet, Erik W; Hilhorst-Hofstee, Yvonne; Haak, Monique C; van den Hoek, Joop; Oepkes, Dick; Lopriore, Enrico

    2015-10-01

    Hypospadias is associated with twinning. The incidence of hypospadias in monochorionic and dichorionic male twins is, however, yet to be determined. All medical records of monochorionic and dichorionic twins admitted to our neonatal nursery between January 2004 and August 2013 were reviewed for the presence of hypospadias. A total of 350 monochorionic and 303 dichorionic male twins were included in the study. The incidence of hypospadias in monochorionic and dichorionic groups was 4% (14/350) and 1% (3/303) (p = .016) respectively. In 11 of the 15 twin couples, hypospadias occurred in the twin with the lowest birth weight. The rate of hypospadias in twin infants small-for-gestational-age group was 10% (6/60) compared with 2% (11/593) in the appropriate-for-gestational-age group (p = .002). In a multivariate analysis, both monochorionicity and small-for-gestational-age were independently associated with hypospadias, odds ratio 4.1 (95% confidence interval (CI): 1.1-14.7) and 6.1 (95% CI: 2.2-17.2) respectively. The incidence of hypospadias is four-fold higher in monochorionic twins compared with dichorionic twins. Hypospadias is also independently associated with small-for-gestational-age.

  19. Myocardial hypertrophy in the recipient with twin-to-twin transfusion syndrome

    DEFF Research Database (Denmark)

    Jeppesen, D.L.; Jorgensen, F.S.; Pryds, O.A.

    2008-01-01

    In a set of monochorionic-diamniotic twins with twin-to-twin transfusion syndrome, systemic hypertension and biventricular myocardial hypertrophy were found in the recipient. The infant developed mild respiratory distress. A partial exchange transfusion was performed because of polycytaemia. Blood...

  20. Rapid onset of severe twin-twin transfusion syndrome caused by placental venous thrombosis

    NARCIS (Netherlands)

    Nikkels, PGJ; van Gemert, MJC; Sollie-Szarynska, KM; Molendijk, H; Timmer, B; Machin, GA

    2002-01-01

    We report a case of rapid onset of severe twin-twin transfusion syndrome (TTTS) at 25 weeks gestation in a monochorionic twin pregnancy that was uneventful before that time. Thrombosis of a main venous branch draining several arteriovenous (AV) anastomoses to the donor changed the previous

  1. Problem in twin pregnancy: Findings of prenatal sonography and autopsy

    International Nuclear Information System (INIS)

    Kim, Jeong Ah; Cho, Jeong Yeon; Song, Mi Jin; Min, Jee Yeon; Lee, Young Ho; Lee, Hak Jong; Chun, Yi Kyeong; Kim, Yee Jeong; Hong, Sung Ran

    2001-01-01

    Multifetal gestations are high risk pregnancies with higher perinatal morbidity and mortality. Multifetal gestations are subject to unique complications including conjoined twins, twin-to-twin transfusion syndrome (TTTS), acardiac twins, twin embization of co-twin demise and heterotopic pregnancies. Prenatal sonographic diagnosis of types and complications of multifetal gestations is important for antenatal care and prediction of fetal outcome. This study was performed to present the prenatal ultrasonographic findings and pathologic findings of the unique complications of twin pregnancy. Acardia is a lethal anomaly occurring in 1% of monozygotic twin. The acardiac twin has a parasitic existence and depends on the donor (pump) twin for its blood supply via placental anastomoses and retrograde perfusion of umbilical cord. This twin reversed arterial perfusion (TRAP) sequence is a most extreme manifestation on the TTTS. Doppler verification reversed flow in umbilical cord of the acardiac twin confirms the diagnosis.

  2. Numerical simulation of a twin screw expander for performance prediction

    Science.gov (United States)

    Papes, Iva; Degroote, Joris; Vierendeels, Jan

    2015-08-01

    With the increasing use of twin screw expanders in waste heat recovery applications, the performance prediction of these machines plays an important role. This paper presents a mathematical model for calculating the performance of a twin screw expander. From the mass and energy conservation laws, differential equations are derived which are then solved together with the appropriate Equation of State in the instantaneous control volumes. Different flow processes that occur inside the screw expander such as filling (accompanied by a substantial pressure loss) and leakage flows through the clearances are accounted for in the model. The mathematical model employs all geometrical parameters such as chamber volume, suction and leakage areas. With R245fa as working fluid, the Aungier Redlich-Kwong Equation of State has been used in order to include real gas effects. To calculate the mass flow rates through the leakage paths formed inside the screw expander, flow coefficients are considered as constant and they are derived from 3D Computational Fluid Dynamic calculations at given working conditions and applied to all other working conditions. The outcome of the mathematical model is the P-V indicator diagram which is compared to CFD results of the same twin screw expander. Since CFD calculations require significant computational time, developed mathematical model can be used for the faster performance prediction.

  3. Twin-Foucault imaging method

    Science.gov (United States)

    Harada, Ken

    2012-02-01

    A method of Lorentz electron microscopy, which enables observation two Foucault images simultaneously by using an electron biprism instead of an objective aperture, was developed. The electron biprism is installed between two electron beams deflected by 180° magnetic domains. Potential applied to the biprism deflects the two electron beams further, and two Foucault images with reversed contrast are then obtained in one visual field. The twin Foucault images are able to extract the magnetic domain structures and to reconstruct an ordinary electron micrograph. The developed Foucault method was demonstrated with a 180° domain structure of manganite La0.825Sr0.175MnO3.

  4. Twin Studies of Atopic Dermatitis

    DEFF Research Database (Denmark)

    Elmose, Camilla; Thomsen, Simon Francis

    2015-01-01

    about filaggrin and its role in the atopic march and provide suggestions for future research in this area. Methods. We identified all twin studies (published after 1970) that have calculated the concordance rate and/or the heritability of AD, or the genetic and environmental correlations between AD...... was around 85% explained by genetic pleiotropy. Conclusions. Genetic factors account for most of the variability in AD susceptibility and for the association between AD and asthma. Controversy remains as to whether the atopic diseases are causally related or whether they are diverse clinical manifestations...

  5. Ectodermal dysplasia in identical twins

    Directory of Open Access Journals (Sweden)

    Gurkar Haraswarupa Puttaraju

    2013-01-01

    Full Text Available Hereditary hypohidrotic ectodermal dysplasia (HED is typically inherited as an X-linked recessive trait, characterized by deformity of at least two or more of the ectodermal structures - hair, teeth, nails and sweat glands. Two cases of hereditary HED involving identical male twins, is being documented for the rarity of its occurrence with special attention given to genetics, pathophysiology, clinical, intraoral manifestations and to the methods to improve the masticatory function, the facial esthetics and psychology of patients affected by this disease.

  6. Haemodynamic resistance model of monochorionic twin pregnancies complicated by acardiac twinning

    Energy Technology Data Exchange (ETDEWEB)

    Umur, Asli [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Amsterdam(Netherlands); Gemert, Martin J C van [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Wijngaard, Jeroen P H M van den [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Ross, Michael G [Department of Obstetrics and Gynecology, Harbor University of California-Los Angeles Medical Center, Torrence, CA 9050 (United States); Nikkels, Peter G J [Department of Pathology, University Medical Center, Utrecht (Netherlands)

    2004-07-21

    An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauterine or neonatally in about 50% of the cases due to congestive heart failure, polyhydramnios and prematurity. Because the pathophysiology of this pregnancy is currently incompletely understood, we modified our previous haemodynamic model of monochorionic twins connected by placental vascular anastomoses to include the analysis of acardiac twin pregnancies. We incorporated the fetoplacental circulation as a resistance circuit and used the fetal umbilical flow that perfuses the body to define fetal growth, rather than the placental flow as done previously. Using this modified model, we predicted that the pump twin has excess blood volume and increased mean arterial blood pressure compared to those in the acardiac twin. Placental perfusion of the acardiac twin is significantly reduced compared to normal, as a consequence of an increased venous pressure, possibly implying reduced acardiac placental growth. In conclusion, the haemodynamic analysis may contribute to an increased knowledge of the pathophysiologic consequences of an acardiac body mass for the pump twin. (note)

  7. NOTE: Haemodynamic resistance model of monochorionic twin pregnancies complicated by acardiac twinning

    Science.gov (United States)

    Umur, Asli; van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Ross, Michael G.; Nikkels, Peter G. J.

    2004-07-01

    An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauterine or neonatally in about 50% of the cases due to congestive heart failure, polyhydramnios and prematurity. Because the pathophysiology of this pregnancy is currently incompletely understood, we modified our previous haemodynamic model of monochorionic twins connected by placental vascular anastomoses to include the analysis of acardiac twin pregnancies. We incorporated the fetoplacental circulation as a resistance circuit and used the fetal umbilical flow that perfuses the body to define fetal growth, rather than the placental flow as done previously. Using this modified model, we predicted that the pump twin has excess blood volume and increased mean arterial blood pressure compared to those in the acardiac twin. Placental perfusion of the acardiac twin is significantly reduced compared to normal, as a consequence of an increased venous pressure, possibly implying reduced acardiac placental growth. In conclusion, the haemodynamic analysis may contribute to an increased knowledge of the pathophysiologic consequences of an acardiac body mass for the pump twin.

  8. Cord entanglement in monoamniotic twin pregnancies

    DEFF Research Database (Denmark)

    Lyndrup, J; Schouenborg, Lars Øland

    1987-01-01

    Monoamniotic twin pregnancy involves a heavy risk of fatal umbilical cord entanglement. Two cases are reported. In the first case, both twins were found dead in the 36th week, and the monoamnionicity was recognized at birth. In the second case, the monoamnionicity was discovered during...

  9. Fetal behavior in normal dichorionic twin pregnancy

    NARCIS (Netherlands)

    Mulder, E. J. H.; Derks, J. B.; de Laat, M. W. M.; Visser, G. H. A.

    2012-01-01

    Objectives: A prospective study was performed to compare fetal behavioral development in healthy dichorionic twins and singletons, and identify twin intra-pair associations (synchrony) of fetal movements and rest-activity cycles using different criteria to define synchrony. Subjects and methods:

  10. 49 CFR 372.221 - Twin Cities.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Twin Cities. 372.221 Section 372.221... ZONES, AND TERMINAL AREAS Commercial Zones § 372.221 Twin Cities. For the purpose of determining... following combinations of cities shall be considered as a single municipality: (a) Having a population equal...

  11. Utilizing twins as controls for non-twin case-materials in genome wide association studies.

    Directory of Open Access Journals (Sweden)

    Andrea Ganna

    Full Text Available Twin registries around the globe have collected DNA samples from large numbers of monozygotic and dizygotic twins. The twin sample collections are frequently used as controls in disease-specific studies together with non-twins. This approach is unbiased under the hypothesis that twins and singletons are comparable in terms of allele frequencies; i.e. there are no genetic variants associated with being a twin per se. To test this hypothesis we performed a genome-wide association study comparing the allele frequency of 572,352 single nucleotide polymorphisms (SNPs in 1,413 monozygotic (MZ and 5,451 dizygotic (DZ twins with 3,720 healthy singletons. Twins and singletons have been genotyped using the same platform. SNPs showing association with being a twin at P-value < 1 × 10(-5 were selected for replication analysis in 1,492 twins (463 MZ and 1,029 DZ and 1,880 singletons from Finland. No SNPs reached genome-wide significance (P-value < 5 × 10(-8 in the main analysis combining MZ and DZ twins. In a secondary analysis including only DZ twins two SNPs (rs2033541 close to ADAMTSL1 and rs4149283 close to ABCA1 were genome-wide significant after meta-analysis with the Finnish population. The estimated proportion of variance on the liability scale explained by all SNPs was 0.08 (P-value=0.003 when MZ and DZ were considered together and smaller for MZ (0.06, P-value=0.10 compared to DZ (0.09, P-value=0.003 when analyzed separately. In conclusion, twins and singletons can be used in genetic studies together with general population samples without introducing large bias. Further research is needed to explore genetic variances associated with DZ twinning.

  12. Twins in Ancient Greece: a synopsis.

    Science.gov (United States)

    Malamitsi-Puchner, Ariadne

    2016-01-01

    This brief outline associates twins with several aspects of life in Ancient Greece. In Greek mythology twins caused ambivalent reactions and were believed to have ambivalent feelings for each other. Very often, they were viewed as the representatives of the dualistic nature of the universe. Heteropaternal superfecundation, which dominates in ancient myths, explains on one hand, the god-like qualities and, on the other hand, the mortal nature of many twins. An assumption is presented that legends referring to twins might reflect the territorial expansions of Ancient Greeks in Northern Mediterranean, around the Black Sea, in Asia Minor, as well as North East Africa. In conclusion, in Greek antiquity, twins have been used as transitional figures between myth and reality.

  13. Urticaria in monozygotic and dizygotic twins

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; van der Sluis, Sophie; Kyvik, Kirsten Ohm

    2012-01-01

    Aim. To identify risk factors for urticaria, to determine the relative proportion of the susceptibility to urticaria that is due to genetic factors in an adult clinical twin sample, and to further determine whether the genetic susceptibility to urticaria overlaps with the genetic susceptibility...... to atopic diseases. Methods. A total of 256 complete twin pairs and 63 single twins, who were selected from sibships with self-reported asthma via a questionnaire survey of 21,162 adult twins from the Danish Twin Registry, were clinically interviewed about a history of urticaria and examined for atopic...... diseases. Data were analysed with Cox proportional hazards regression and variance components models. Results. A total of 151 individuals (26%) had a history of urticaria, whereas 24 (4%) had had symptoms within the past year. Female sex, HR = 2.09 (1.46-2.99), P = 0.000; hay fever, HR = 1.92 (1...

  14. Shock-induced deformation twinning in tantalum

    International Nuclear Information System (INIS)

    Murr, L.E.; Niou, C.S.; Pappu, S.; Kennedy, C.; Meyers, M.A.; Chen, Y.J.

    1997-01-01

    Shock-wave deformation of tantalum to a pressure of 45 GPa and duration of 1.8 micros generates profuse twinning. The post-shock mechanical response is significantly affected, with shock hardening exceeding the expected hardening due to the transient shock strain ε s = (4/3)ln(V/V 0 ); this enhanced hardening, and other alterations in response, are attributed to the barriers presented to plastic deformation by the deformation twins. A constitutive model is proposed that predicts the threshold shock stress for mechanical twinning; it is based on the application of the Swegle-Grady relationship between shock stress and strain rate to constitute equations describing the critical stress for slip and twinning. This constitutive model incorporates grain-size effects and predicts a threshold twinning stress that is a function of temperature and grain size; predictions of the model are in qualitative agreement with experimental results

  15. 'Biracial'-Looking Twins: A New Twin Type?/Twin Research: Twins with Cystic Teratomas; Sleep Quality and Body Mass Index; Previable Membrane Rupture/Print and Online Reports: Twins Born to a Sister Surrogate; NASA Twin Study; African-Cosmopolitan Twin Fashion Inspirations; Triplet Hockey Stars.

    Science.gov (United States)

    Segal, Nancy L

    2017-06-01

    Dizygotic (DZ) co-twins born to mothers and fathers from different racial or ethnic backgrounds often resemble one parent much more than the other. As such, these pairs comprise a unique subset of twins for investigating how others' responses to their different looks may affect their personalities and self-esteem. This article describes some of these twin pairs and some challenges of raising them, and suggests ways they may be used in research. Next, recent twin research on cystic teratomas, relations between sleep quality and body mass index, and previable membrane rupture is described. The final section concerns twins, twin studies, and related events in the media, namely: twins born to a sister surrogate, the NASA twin investigation, inspiring African-Cosmopolitan twins in fashion, and triplet Hockey Stars.

  16. Highlights from the 15th International Congress of Twin Studies/Twin Research: Differentiating MZ Co-twins Via SNPs; Mistaken Infant Twin-Singleton Hospital Registration; Narcolepsy With Cataplexy; Hearing Loss and Language Learning/Media Mentions: Broadway Musical Recalls Conjoined Hilton Twins; High Fashion Pair; Twins Turn 102; Insights From a Conjoined Twin Survivor.

    Science.gov (United States)

    Segal, Nancy L

    2015-02-01

    Highlights from the 15th International Congress of Twin Studies are presented. The congress was held November 16-19, 2014 in Budapest, Hungary. This report is followed by summaries of research addressing the differentiation of MZ co-twins by single nucleotide polymorphisms (SNPs), an unusual error in infant twin-singleton hospital registration, twins with childhood-onset narcolepsy with cataplexy, and the parenting effects of hearing loss in one co-twin. Media interest in twins covers a new Broadway musical based on the conjoined twins Violet and Daisy Hilton, male twins becoming famous in fashion, twins who turned 102 and unique insights from a conjoined twin survivor. This article is dedicated to the memory of Elizabeth (Liz) Hamel, DZA twin who met her co-twin for the first time at age seventy-eight years. Liz and her co-twin, Ann Hunt, are listed in the 2015 Guinness Book of Records as the longest separated twins in the world.

  17. Modelling the influence of amnionicity on the severity of twin-twin transfusion syndrome in monochorionic twin pregnancies

    International Nuclear Information System (INIS)

    Wijngaard, Jeroen P H M van den; Umur, Asli; Ross, Michael G; Gemert, Martin J C van

    2004-01-01

    Clinical treatment for diamniotic-monochorionic twin-twin transfusion syndrome (TTTS) may include conversion of diamniotic pregnancies to a monoamniotic-monochorionic state by disrupting the amnion septum. We sought to test the underlying hypothesis, i.e. that a monoamniotic state reduces the severity of TTTS. With use of our previously developed mathematical model of two equal fetoplacental circulatory units connected by various sizes and types of placental anastomoses, we compared the haemodynamic and amniotic fluid dynamics of monoamniotic and diamniotic twins that develop TTTS. We used three anastomotic patterns that produce severe, moderate or mild forms of TTTS, respectively, in our diamniotic-monochorionic twin model. Monoamnionicity was modelled by adding the two amniotic fluid volumes and using the volume-averaged amniotic fluid osmolality. The results were as follows: for severe TTTS, small differences develop between diamniotic and monoamniotic donor twins in fetal urine production, swallowed volume, blood volume, blood pressures, net fetofetal transfusion, and blood and amniotic fluid osmolality. However, the circulatory imbalance between the monoamniotic twins deteriorates similar to that of diamniotic twins. The pathophysiological differences tend to disappear for milder TTTS. In conclusion, our model suggests that the uncommon finding of TTTS in monoamniotic twins is not due to the presence of a single amniotic sac. Rather, clinically significant differences in anastomotic patterns and the delayed or lack of identification of manifestations in monoamniotic twins account for the reduced rate of TTTS diagnosis. Based on these results we expect the clinical disruption of the amnion septum in diamniotic-monochorionic TTTS pregnancies to have only minimal benefits. (note)

  18. The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design.

    Science.gov (United States)

    Iacono, William G; Heath, Andrew C; Hewitt, John K; Neale, Michael C; Banich, Marie T; Luciana, Monica M; Madden, Pamela A; Barch, Deanna M; Bjork, James M

    2017-09-12

    The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006-2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Establishing a Twin Registry in Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, Morten; Gomes, Margarida A; Joaquím, Luis C

    2013-01-01

    represent a powerful tool. Though twin studies have been carried out by the Bandim Health Project for more than 30 years, the renewed registry described here was officially established in 2009 and includes both a cohort of newborn twins and a cohort of young and adult twins. Currently more than 1,500 twins...

  20. Acardiac acephalus twin: A case report | Bukar | Tropical Journal of ...

    African Journals Online (AJOL)

    Acardiac acephalus twin is a rare complication of monochorionic twinning. A case of a 26year old who presented to the emergency unit of the University of Maiduguri Teaching Hospital [UMTH] with ultrasound report of non viable but morphologically normal twin pregnancy is presented. She was delivered of a twin still born; ...

  1. Rare Complications with Monochorionic Twins: Ultrasonography and Pathology Correlations

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi Jin [Cheil General Hospital and Women' s Healthcare Center, Kwandong University College of Medicine, Seoul (Korea, Republic of)

    2009-12-15

    We reviewed the sonographic features of rare complications with monochorionic twins and we correlated these features with the pathologic findings. The complications, including the twin reversed arterial perfusion sequence, the twin embolization syndrome, the conjoined twins and umbilical cord entanglement. A better understanding of these complications can aid making an accurate prenatal diagnosis and predicting the fetal outcome

  2. Obstetric Outcome in Twin Gestation in a Nigerian Tertiary Hospital ...

    African Journals Online (AJOL)

    BACKGROUND: Twin pregnancies are high risk pregnancies. Foetal and maternal complications are common in twin pregnancies. Therefore, periodic review is necessary to improve on the twin pregnancy outcome. OBJECTIVE: To determine the incidence and outcome of twin pregnancies in the hospital. MATERIALS AND ...

  3. Twin Delivery: Comparison of Incidence and Foetal Outcome in two ...

    African Journals Online (AJOL)

    Background: The incidence of twin delivery in Nigeria may have changed, in view of the worldwide increase in the rates of twinning attributed to increasing maternal age and use of fertility therapies. Objective: To determine the current incidence of twin delivery in Benin City and document the foetal outcome in twins.

  4. What kind of twins were Jacob and Esau?

    African Journals Online (AJOL)

    common (or uncommon) then as it is now, the incidence of twins today being once in every 80 pregnancies, with dizygotic twins occurring three times more frequently than monozygotic twins.' The Bible probably only refers to these two particular cases of twin deliveries because they were exceptional: the first deliVery ...

  5. Twin and Triplet Drugs in Opioid Research

    Science.gov (United States)

    Fujii, Hideaki

    Twin and triplet drugs are defined as compounds that contain respectively two and three pharmacophore components exerting pharmacological effects in a molecule. The twin drug bearing the same pharmacophores is a "symmetrical twin drug", whereas that possessing different pharmacophores is a "nonsymmetrical twin drug." In general, the symmetrical twin drug is expected to produce more potent and/or selective pharmacological effects, whereas the nonsymmetrical twin drug is anticipated to show both pharmacological activities stemming from the individual pharmacophores (dual action). On the other hand, nonsymmetrical triplet drugs, which have two of the same pharmacophores and one different moiety, are expected to elicit both increased pharmacological action and dual action. The two identical portions could bind the same receptor sites simultaneously while the third portion could bind a different receptor site or enzyme. This review will mainly focus on the twin and triplet drugs with an evaluation of their in vivo pharmacological effects, and will also include a description of their pharmacology and synthesis.

  6. Acardiac Parabiotic Fetus: A Rare Complication of Twin Pregnancy

    Directory of Open Access Journals (Sweden)

    Sood S

    2015-10-01

    Full Text Available Acardiac parabiotic fetus is sequelae of complication of monochorionic monoamniotic twin pregnancy also known as Twin Reversed Arterial Perfusion Sequence (TRAP. It is rare affecting 1 in 35,000 births and 1 % of monozygotic twins. Acardiac parabiotic twin commonly known as parasite occurs rarely and may lead to high output cardiac failure, hydrops or premature delivery in the pump fetus. In this report, we present a 23 years old primigravida with twin pregnancy, with twin reversed arterial perfusion sequence with one of the twins being acardiac anceps and the other normal pump fetus. This association is relatively uncommon and therefore rarely documented.

  7. Personality traits in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, M; Kyvik, Kirsten Ohm; Mortensen, E L

    2007-01-01

    OBJECTIVE: To examine whether a high genetic liability to develop affective disorder is associated with specific personality traits. METHOD: A cross-sectional, high-risk, case-control study. Through nation-wide registers, healthy monozygotic (MZ) and dizygotic (DZ) twins with (high-risk twins......) and without (the control group/low-risk twins) a co-twin history of affective disorder were identified. Personality traits were compared for a total of 211 high-risk and low-risk twins. RESULTS: In univariate analyses, the high-risk twins had a higher level of neuroticism than the control twins (P = 0...

  8. TwinFocus CPV system

    Science.gov (United States)

    Nardello, Marco; Centro, Sandro

    2017-09-01

    TwinFocus® is a CPV solution that adopts quasi-parabolic, off axis mirrors, to obtain a concentration of 760× on 3J solar cells (Azur space technology) with 44% efficiency. The adoption of this optical solution allows for a cheap, lightweight and space efficient system. In particular, the addition of a secondary optics to the mirror, grants an efficient use of space, with very low thicknesses and a compact modular design. Materials are recyclable and allow for reduction of weights to a minimum level. The product is realized through the cooperation of leading edge industries active in automotive lighting and plastic materials molding. The produced prototypes provide up to 27.6% efficiency according to tests operated on the field with non-optimal spectral conditions.

  9. Breastfeeding Twins: A Qualitative Study

    Science.gov (United States)

    Alvur, Tuncay Muge; Kose, Dilek; Nemut, Tijen

    2013-01-01

    The purpose of this qualitative research was to explore the needs and difficulties of mothers who had multiple babies at Sakarya County by focusing on their breastfeeding experience. Ten mothers who gave birth to multiple infants participated in the study voluntarily. The framework method of data analysis was applied systematically both within and across cases, with categories and themes identified by reading transcripts of interviews. Major themes generated from focus narrative interviews are described. These themes are: willingness of mothers to breastfeed and continue, management of breastfeeding, use of pacifier, daily life, ınstructions of healthcare personnel, and advices from practice of experienced mothers. This study showed that women were aware of the importance of mother's milk for their babies. They all, somehow, made intensive efforts to breastfeed their twins. Women who expect and/or have multiple babies need much more support and guidance, which may include advice for nutritional and daily care. PMID:24592592

  10. Successful twin pregnancy after orthotopic liver transplantation

    Directory of Open Access Journals (Sweden)

    Coelho Júlio Cezar Uili

    2002-01-01

    Full Text Available AIM: Report of a case of successful twin pregnancy following liver transplantation. PATIENT AND METHOD: A 42-year-old nulliparous-woman was subjected to an orthotopic liver transplantation due to Budd-Chiari syndrome. Sixteen months after the transplantation, an ultrasonography revealed twin pregnancy. Her prenatal course was uneventful, except for mild arterial hypertension. The immunosuppressive agents used during pregnancy were cyclosporine and prednisone. RESULT: The patient gave birth to two healthy girls at 37 weeks of gestation. The patient's postpartum course was uneventful with normal liver and renal function tests. CONCLUSION: Following successful pregnancy, women may become pregnant and give birth to normal children, including twins

  11. Undiagnosed xiphopagus twins: a perinatal malady

    Directory of Open Access Journals (Sweden)

    Gowri Dorairajan

    2012-02-01

    Full Text Available Conjoined twins are a very rare entity. It is associated with poor survival rate in the presence of vital organ sharing. The entity can be diagnosed as early as the first trimester. A conjoined twin diagnosed late in labor is a malady with high perinatal mortality and maternal morbidity. We present one such case of xiphopagus twins. The management of a case diagnosed late in labor can be very challenging. Such obstetric challenges can be avoided by a meticulous early scan with a high index of suspicion, especially in the absence of separating membrane while scanning multiple pregnancies.

  12. Twin trisomies-Edward and Patau syndromes.

    Science.gov (United States)

    Massiah, Nadine; Griffiths, Emma; Bamigboye, Vincent

    2008-11-01

    To report the rare occurrence of dichorionic diamniotic twins with dissimilar aneuploidies. Case report. District general hospital. A 36-year-old woman conceived by in vitro fertilization. Dichorionic diamniotic twins were found to have elevated nuchal translucencies and cystic hygromas. Intrauterine deaths occurred at 13 and 17 weeks gestation. Medical termination of pregnancy. Karyotypes. Cytogenetic studies confirmed Edward's and Patau's syndromes. The aetiology is unknown but maternal age and in vitro fertilization may be linked since the incidence of aneuploidy rises with maternal age and the incidence of twins' increases with assisted reproductive techniques. This case highlights the need for obstetricians to have good communication and counselling skills.

  13. Attractiveness Differences Between Twins Predicts Evaluations of Self and Co-Twin

    Science.gov (United States)

    Principe, Connor P.; Rosen, Lisa H.; Taylor-Partridge, Teresa; Langlois, Judith H.

    2012-01-01

    One of the most consistent findings in psychology shows that people prefer and make positive attributions about attractive compared with unattractive people. The goal of the current study was to determine the power of attractiveness effects by testing whether these social judgments are made where attractiveness differences are smallest: between twins. Differences in facial attractiveness predicted twins’ evaluations of self and their co-twin (n = 158; 54 male). In twin pairs, the more attractive twin judged their less attractive sibling as less physically attractive, athletic, socially competent, and emotionally stable. The less attractive twin did the reverse. Given that even negligible differences in facial attractiveness predicted self and co-twin attitudes, these results provide the strongest test yet of appearance-based stereotypes. PMID:23467329

  14. Performance Prediction and Simulation of Gas Turbine Engine Operation for Aircraft, Marine, Vehicular, and Power Generation

    Science.gov (United States)

    2007-02-01

    Single Shaft Gas Turbine . Constant TIT, B-159 Operation with Different Fuels and Water Injection Figure B.147 Schematic Representation of a Twin Spool ...Function of the Amount of Injected B-169 Steam for a Single Shaft Gas Turbine Figure B.155 Change of Compressor Pressure Ratio with Water Injection...Water Injection, for a Twin Shaft Gas Turbine B-171 Figure B.158 Range of Variation of Power Deviation for Existing Gas Turbines

  15. Cohort Profile : The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry)

    NARCIS (Netherlands)

    Gatz, Margaret; Harris, Jennifer R.; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L.; Snieder, Harold; Spiro, Avron; Butler, David A.

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved

  16. Myocardial hypertrophy in the recipient with twin-to-twin transfusion syndrome

    DEFF Research Database (Denmark)

    Jeppesen, D.L.; Jorgensen, F.S.; Pryds, O.A.

    2008-01-01

    In a set of monochorionic-diamniotic twins with twin-to-twin transfusion syndrome, systemic hypertension and biventricular myocardial hypertrophy were found in the recipient. The infant developed mild respiratory distress. A partial exchange transfusion was performed because of polycytaemia. Blood...... pressure measurements revealed persistent systemic hypertension. Biventricular hypertrophy was demonstrated by echocardiography. Blood pressure normalised after treatment with Nifedipine and the cardiac hypertrophy subsided over the following weeks. A potential contributing mechanism is intrauterine...

  17. Removing the twin image in digital holography by segmented filtering of in-focus twin image

    OpenAIRE

    McElhinney, C.; Hennelly, B.M.; Ahrenberg, L.; Naughton, T.J.

    2008-01-01

    We propose and investigate a new digital method for the reduction of twin-image noise from digital Fresnel holograms. For the case of in-line Fresnel holography the unwanted twin is present as a highly corruptive noise when the object image is numerically reconstructed. We propose to firstly reconstruct the unwanted twin-image when it is in-focus and in this plane we calculate a segmentation mask that borders this in focus image. The twin-image is then segmented and removed by sim...

  18. Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

    International Nuclear Information System (INIS)

    Wu, Wei; Gao, Yanfei; Li, Nan; Parish, Chad M.; Liu, Wenjun; Liaw, Peter K.; An, Ke

    2016-01-01

    Deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning-detwinning process, the “twinning-like” lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculation of the lattice strain confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. The study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods.

  19. Micromechanics of twinning in a TWIP steel

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, K.M., E-mail: khandaker.rahman05@imperial.ac.uk [Department of Materials, Royal School of Mines, Imperial College London, Prince Consort Road, London SW7 2BP (United Kingdom); Jones, N.G. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Dye, D. [Department of Materials, Royal School of Mines, Imperial College London, Prince Consort Road, London SW7 2BP (United Kingdom)

    2015-05-21

    The deformation behaviour of a TWinning Induced Plasticity (TWIP) steel was studied at quasi-static strain rates using synchrotron X-ray diffraction. A {111} RD and {200} RD texture developed from the earliest stages of deformation, which could be reproduced using an elasto-plastic self consistent (EPSC) model. Evidence is found from multiple sources to suggest that twinning was occurring before macroscopic yielding. This included small deviations in the lattice strains, {111} intensity changes and peak width broadening all occurring below the macroscopic yield point. The accumulation of permanent deformation on sub-yield mechanical cycling of the material was found, which further supports the diffraction data. TEM revealed that fine deformation twins similar to those observed in heavily deformed samples formed during sub-yield cycling. It is concluded that twinning had occurred before macroscopic plastic deformation began, unlike the behaviour traditionally expected from hexagonal metals such as Mg.

  20. Infantile Perineal Protrusion in Two Monochorionic Twins

    Directory of Open Access Journals (Sweden)

    Paola Cavicchioli

    2014-11-01

    Full Text Available Case Report - Two female monochorionic-monoamniotic twins showed the same kind of infantile perineal protrusion (IPP at birth. Lesions in both twins progressively healed until resolution in 6 weeks' time; none of the twins have manifested, till date, alvus disturbances. Discussion and Literature Review - A literature review numbers approximately 100 reports of IPP. This condition has been classically classified into three categories: congenital/familiar (i.e., female sex, positive parental history of IPP, acquired (mainly due to constipation, and associated with lichen sclerosus et atrophicus. Conclusions and Final Remarks - This case report describes, for the first time, the presence of IPP in monochorionic-monoamniotic twins, supporting the existence of hereditary/genetic factors in the developing of this condition.

  1. Cooperative Research Twin Trawl Sweep Comparison Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Twin-Trawl Sweep Efficiency Study" was intended to compare the sweep efficiency and selectivity of the NEFSC standardized bottom trawl to that of a standardized...

  2. Prevention of preterm delivery in twin pregnancy

    DEFF Research Database (Denmark)

    Rode, Line; Tabor, Ann

    2014-01-01

    The incidence of twin gestation has increased markedly over the past decades, mostly because of increased use of assisted reproductive technologies. Twin pregnancies are at increased risk of preterm delivery (i.e. birth before 37 weeks of gestation). Multiple gestations therefore account for 2...... sequelae such as abnormal neurophysiological development in early childhood and underachievement in school. Several treatment modalities have been proposed in singleton high-risk pregnancies. The mechanism of initiating labour may, however, be different in singleton and twin gestations. Therefore......, it is mandatory to evaluate the proposed treatments in randomised trials of multiple gestations. In this chapter, we describe the results of trials to prevent preterm delivery in twin pregnancies....

  3. Approach towards the digital optical twin

    Science.gov (United States)

    Prochnau, Marcel; Stollenwerk, Jochen; Loosen, Peter

    2017-11-01

    This paper discusses the idea of a Digital Optical Twin (DOT) in the field of optical system assembly. Furthermore, steps required towards this goal concerning the digital representation of a physical system are presented.

  4. Diabetes and Menopause: A Twin Challenge

    Science.gov (United States)

    Diabetes and menopause: A twin challenge Diabetes and menopause may team up for varied effects on your body. Here's what to ... to stay in control. By Mayo Clinic Staff Menopause — and the years leading up to it — may ...

  5. Twin Screw Mixer/Fine Grind Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The 40-mm Twin-Screw Mixer/Extruder (TSE) pilot plant is a continuous, remotely operated, flexible facility that can significantly enhance safety and environmental...

  6. Twin Cities Metro Hybrid Landcover 2000 (Raster)

    Data.gov (United States)

    Minnesota Department of Natural Resources — The Hybrid Landcover is an attempt to clean up the University of Minnesota Remote Sensing Lab's 2000 LandSat Land Cover for the Twin Cities 7-county metropolitan...

  7. Pulmonary interstitial glycogenosis in identical twins

    NARCIS (Netherlands)

    Onland, W.; Molenaar, J. J.; Leguit, R. J.; Van Nierop, J. C.; Noorduyn, L. A.; van Rijn, R. R.; Geukers, V. G. M.

    2005-01-01

    We present the clinical, radiological, and pathological findings of open lung biopsies from monozygotic prematurely born male twins with respiratory distress at ages 6 and 8 weeks postnatally Radiological examination showed a reticular nodular interstititial pattern on chest radiography

  8. Twin screw subsurface and surface multiphase pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dass, P. [CAN-K GROUP OF COMPANIES, Edmonton, Alberta (Canada)

    2011-07-01

    A new subsurface twin screw multiphase pump has been developed to replace ESP and other artificial lift technologies. This technology has been under development for a few years, has been field tested and is now going for commercial applications. The subsurface twin screw technology consists of a pair of screws that do not touch and can be run with a top drive or submersible motor; and it carries a lot of benefits. This technology is easy to install and its low slippage makes it highly efficient with heavy oil. In addition twin screw multiphase pumps are capable of handling high viscosity fluids and thus their utilization can save water when used in thermal applications. It also induces savings of chemicals because asphaltenes do not break down easily as well as a reduction in SOR. The subsurface twin screw multiphase pump presented herein is an advanced technology which could be used in thermal applications.

  9. Screening and Invasive Testing in Twins

    Directory of Open Access Journals (Sweden)

    Giovanni Monni

    2014-07-01

    Full Text Available Prenatal screening and testing for trisomy 21 in twin pregnancies poses a number of challenges: the exact estimate of the a priori risk of trisomy 21, the choice of prenatal screening test and/or invasive techniques to employ for the diagnosis and the impact of the result on the options of treatment in case of discordant results within a twin pair or among multiples. These different aspects are discussed below while recognizing that many issues remain unresolved.

  10. Twin birth order, birthweight and birthweight discordance: any relationship

    Directory of Open Access Journals (Sweden)

    Onyiriuka A.N.

    2010-12-01

    Full Text Available Background: It is widely believed that in twin pairs, at birth, the first-born weigh more than the second-born but this concept has been challenged. Objective: To assess the truthfulness of this common concept that first-born twins are usually heavier than their second-born siblings at birth. Methods: In a series of 104 sets of live-born twins, the birth weights of first-born twins were compared with those of their second-born siblings, after controlling for gender. Their intra-pair birthweight differences were determined and twin pairs whose birthweight difference was 15% or more were designated as discordant. Results: Twin I was heavier than Twin II in 61.5% of cases while Twin II was heavier than Twin I in 28.9% of cases. Twins I and II had equal birthweights in 9.6% of cases. Comparing the mean birthweight of the first-born-male twin with that of second-born- male twin, it was 2515+427g (95% Confidence Interval, CI=2402-2628 versus 2432 +435g (95% CI=2321-2543 p>0.05. The mean birthweight of first-born-female twin was 2326+445g (95% CI=2214-2439 while that of the second-born-female twin was 2325+501g (95% CI=2197-2453 p>0.05. When the birthweight difference exceeded 750g, the probability that Twin I will be heavier than Twin II was 83.3% (5 of 6. Conclusion: Although the first-born twin was more often heavier than their second-born siblings, either could weigh more or less at birth. The larger the birthweight difference between growth-discordant twin pair, the greater the probability that the heavier twin would be delivered first

  11. Twin pregnancy in the congenital malformed uterus.

    Science.gov (United States)

    Heinonen, Pentti K

    2016-07-01

    The frequency and outcome of twin pregnancies in women with uterine malformation were studied. The cohort comprised 13 (4.9%) women with twin pregnancy found among 263 women. They had 483 deliveries, 13 of them twins (2.7%; 95% CI 1.6-4.6%). Among 38 patients with unicornuate uterus 5 (6.8%) out of 74 deliveries were twins, 39 women with didelphic uterus 2 (3.2%) out of 62 deliveries and 147 women with septate or subseptate uterus 6 (2.3%) out of 264 deliveries were twins. The mean duration of gestation was 249 days (range 190-268 days), 5 (38%) out of 13 deliveries were premature, 25 out of 26 newborns were alive. Mean durations of gestation and mean weights of newborns did not differ when 7 cases with unicornuate or didelphic uterus were compared to 6 cases with complete or partial uterine septum. A congenital malformed uterus can bear twin pregnancy without severe complications apart from prematurity.

  12. Imperfect twinning: a clinical and ethical dilemma.

    Science.gov (United States)

    Denardin, Daniela; Telles, Jorge Alberto B; Betat, Rosilene da Silveira; Fell, Paulo Renato K; Cunha, André Campos da; Targa, Luciano Vieira; Zen, Paulo Ricardo G; Rosa, Rafael Fabiano M

    2013-09-01

    OBJECTIVE To review the history, epidemiology, etiology, gestational aspects, diagnosis and prognosis of imperfect twinning. DATA SOURCES Scientific articles were searched in PubMed, SciELO and Lilacs databases, using the descriptors "conjoined twins", "multiple pregnancy", "ultrasound", "magnetic resonance imaging" and "prognosis". The research was not delimited to a specific period of time and was supplemented with bibliographic data from books. The description of conjoined twins is legendary. The estimated frequency is 1/45,000-200,000 births. These twins are monozygotic, monochorionic and usually monoamniotic. They can be classified by the most prominent fusion site, by the symmetry between the conjoined twins or by the sharing structure. The diagnosis can be performed in the prenatal period or after birth by different techniques, such as ultrasound, magnetic resonance imaging and echocardiography. These tests are of paramount importance for understanding the anatomy of both fetuses/children, as well as for prognosis and surgical plan determination. CONCLUSIONS Although imperfect twinning is a rare condition, the prenatal diagnosis is very important in order to evaluate the fusion site and its complexity. Hence, the evaluation of these children should be multidisciplinary, involving mainly obstetricians, pediatricians and pediatric surgeons. However, some decisions may constitute real ethical dilemmas, in which different points should be discussed and analyzed with the health team and the family.

  13. Laying the ghost of twin paradox

    Directory of Open Access Journals (Sweden)

    Popović Marko

    2009-01-01

    Full Text Available Someone's true age is not written in his ID, but in his biomarkers. Aging process is not caused by time passing, but by thermodynamically laws. Entropy, extent of metabolic reaction, and temperature are Lorentz invariant, so these facts make twin paradox impossible because there is no way for one twin to age slower than the other even if the time in his frame is dilated. Entropy is the function of state, not time. So as much as standard thermodynamics concerns, the path between two points in space is equivalent to the path between two states. Whether the point B is reached by moving faster using the longer way (with time dilatation, or slower by using shortcut (without time dilatation, the state of the system after completing the road should be the same. This is supported by the fact that when two twins reach the same space-time point (point B in which the state parameters are the same. If we use entropy as an age parameter, then both twins have the same entropy value and are exactly the same biological age. Therefore, the twin paradox is a logical mistake based on wrong first premise. Bergson symmetry is not necessary any more to explain the impossibility of twin paradox.

  14. Twin bands in martensites: Statics and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Horovitz, B. (Department of Physics, Ben-Gurion University, P.O. Box 653, Beer-Sheva, 84105, Israel (IL)); Barsch, G.R. (Materials Research Laboratory and Department of Physics, Pennsylvania State University, University Park, Pennsylvania (USA)); Krumhansl, J.A. (Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York (USA))

    1991-01-01

    The theory of forming a coherent twin band and its relation to the parent-product interface in a martensitic transition is studied. We find that the twin band is stabilized by a long-range elastic interaction between the twin boundaries, which is mediated via the parent phase. The mean distance {ital l} between twin boundaries is then {ital l}{similar to} {radical}{ital L}{sub 2} , with {ital L}{sub 2} the size of a twin boundary, i.e., the product grain'' size. The collective twin-boundary oscillations ( dyadons'') have unusually low frequencies and a limiting dispersion of frequency, which goes as the square root of the wave vector. Explicit results are given for a tetragonal-to-orthorhombic transition. We also show that dyadons cause the specific heat to change from a {ital T}{sup 3} temperature dependence to {ital T}{sup 2} at lower temperatures and to allow for a linear temperature dependence of the resistivity to extend to low temperatures. We compare our results with data on conventional martensites and on the more recent ceramic superconductors.

  15. Severe twin-to-twin transfusion syndrome in a scared uterus ...

    African Journals Online (AJOL)

    Background: Twin-to-twin transfusion syndrome (TTTS) is a vascular abnormality unique to monochorionic pregnancies. The associated polyhydramniosportends significant risk to uterine rupture especially in a scared uterus. Serial amnioreduction is an established technique that reduces the risks of severe polyhydramnios ...

  16. Aeroacoustic Experiments with Twin Jets

    Science.gov (United States)

    Bozak, Richard F.; Henderson, Brenda S.

    2012-01-01

    While the noise produced by a single jet is azimuthally symmetric, multiple jets produce azimuthally varying far-field noise. The ability of one jet to shield another reduces the noise radiated in the plane of the jets, while often increasing the noise radiated out of the plane containing the jets. The present study investigates the shielding potential of twin jet configurations over subsonic and over-expanded supersonic jet conditions with simulated forward flight. The experiments were conducted with 2 in. throat diameter nozzles at four jet spacings from 2.6d to 5.5d in center-to-center distance, where d is the nozzle throat diameter. The current study found a maximum of 3 dB reduction in overall sound pressure level relative to two incoherent jets in the peak jet noise direction in the plane containing the jets. However, an increase of 3 dB was found perpendicular to the plane containing the jets. In the sideline direction, shielding is observed for all jet spacings in this study.

  17. Niobium and tantalum: indispensable twins

    Science.gov (United States)

    Schulz, Klaus; Papp, John

    2014-01-01

    Niobium and tantalum are transition metals almost always paired together in nature. These “twins” are difficult to separate because of their shared physical and chemical properties. In 1801, English chemist Charles Hatchett uncovered an unknown element in a mineral sample of columbite; John Winthrop found the sample in a Massachusetts mine and sent it to the British Museum in London in 1734. The name columbium, which Hatchet named the new element, came from the poetic name for North America—Columbia—and was used interchangeably for niobium until 1949, when the name niobium became official. Swedish scientist Anders Ekberg discovered tantalum in 1802, but it was confused with niobium, because of their twinned properties, until 1864, when it was recognized as a separate element. Niobium is a lustrous, gray, ductile metal with a high melting point, relatively low density, and superconductor properties. Tantalum is a dark blue-gray, dense, ductile, very hard, and easily fabricated metal. It is highly conductive to heat and electricity and renowned for its resistance to acidic corrosion. These special properties determine their primary uses and make niobium and tantalum indispensable.

  18. Art for twins: Yorùbá artists and their statues/twin research studies: twins' education and conceptions; diurnal preference; inherited eye diseases; ultrasound counseling when twins are conjoined/popular twin reports: twin sisters (the film); rare pregnancy; diet test; French twins reared apart and reunited.

    Science.gov (United States)

    Segal, Nancy L

    2014-06-01

    The Yorùbá of Nigeria are well known for their high twinning rate and the statues they create to commemorate deceased twins. An impressive collection of this artwork was displayed at the University of California's Fowler Museum in Los Angeles between October 13, 2013 and March 2, 2014. An overview of this exhibit is provided. Next, twin research on maternal education and conception, diurnal preference, inherited eye diseases, and ultrasound counseling for couples with conjoined twins are briefly summarized. This article concludes with a discussion of media-based items related to twins. The topics include an award-winning twin film, a rare pregnancy, a diet test, and the separation and chance reunion of monozygotic female twins.

  19. Xipho-omphalopagous twins--separation in the newborn.

    Directory of Open Access Journals (Sweden)

    Birmole B

    1993-04-01

    Full Text Available Male conjoined twins (thoraco-omphalopagous were delivered by emergency Caesarean section performed in a full term, 3rd gravida who had presented in labour. On examination one of the twins had gross monstrosity and was threatening the survival of the better twin (twin A. The cannulation and dye studies through single umbilical vein demonstrated significant cross circulation across the connecting bridge. The vein was connected to liver of twin A. An emergency separation was performed to salvage the better twin.

  20. DNA stability and schizophrenia in twins.

    Science.gov (United States)

    Nguyen, Giang H; Bouchard, Joseph; Boselli, Monica G; Tolstoi, Linda G; Keith, Louis; Baldwin, Clinton; Nguyen, Nam C; Schultz, Mark; Herrera, Victoria L M; Smith, Cassandra L

    2003-07-01

    The goal of these experiments was to understand DNA changes relevant to schizophrenia. This work compared DNA of monozygotic (MZ) twins surrounding (CAG)(n) repeating sequences, and characterized the relationship between fragile sites and schizophrenia. Twelve twin-pairs, previously classified as MZ and 18 unrelated sib-pairs, from seven families were studied. Eight twin-pairs were affected by schizophrenia, four concordantly and four discordantly. DNA comparisons were made using profiles of electrophoretic size fractionations of PCR amplified (CAG)(n) containing genomic fragments. These profiles were generated by a new method, developed by us, called targeted genomic differential display (TGDD). Surprisingly, the number of peak profile differences in MZ twin-pairs discordant for schizophrenia was greater than the concordantly ill twins and the well twins and, in some cases, overlapped the range of sib-pairs. These results might mean that some twins were not MZ but it was not possible to definitively test these samples for zygosity. Alternatively, the results might be explained as an increased mutation rate (or genomic instability) around (CAG)(n) sites in individuals afflicted with schizophrenia. Also, we uncovered an association of schizophrenia (i.e., a linkage of chromosomal abnormalities and gene localizations) with fragile sites spread throughout the genome (chi(2), P = 0.001). Furthermore, it appears that an increasing number of genes linked to schizophrenia are associated with (CAG)(n) sequences. Fragile sites and (CAG)(n) repeat sequences are known to be unstable. We speculate the association of genomic instability with schizophrenia accounts for seemingly disparate biological and environmental factors that influence disease occurrence. Copyright 2003 Wiley-Liss, Inc.

  1. Diabetes and perinatal mortality in twin pregnancies.

    Directory of Open Access Journals (Sweden)

    Zhong-Cheng Luo

    Full Text Available BACKGROUND: Diabetes in pregnancy has been associated with a paradoxically reduced risk of neonatal death in twin pregnancies. Risk "shift" may be a concern in that the reduction in neonatal deaths may be due to an increase in fetal deaths (stillbirths. This study aimed to clarify the impact of diabetes on the risk of perinatal death (neonatal death plus stillbirth in twin pregnancies. METHODS: This was a retrospective cohort study of twin births using the largest available dataset on twin births (the U.S. matched multiple birth data 1995-2000; 19,676 neonates from diabetic pregnancies, 541,481 from non-diabetic pregnancies. Cox proportional hazard models were applied to estimate the adjusted hazard ratios (aHR of perinatal death accounting for twin cluster-level dependence. RESULTS: Comparing diabetic versus non-diabetic twin pregnancies, overall perinatal mortality rate was counterintuitively lower [2.1% versus 3.3%, aHR 0.70 (95% confidence intervals 0.63-0.78]. Individually, both stillbirth and neonatal mortality rates were lower in diabetic pregnancies, but we identified significant differences by gestational age and birth weight. Diabetes was associated with a survival benefit in pregnancies completed before 32 weeks [aHR 0.55 (0.48-0.63] or with birth weight =2500 g [aHR 2.20 (1.55-3.13]. CONCLUSIONS: Diabetes in pregnancy appears to be "protective" against perinatal death in twin pregnancies ending in very preterm or very low birth weight births. Prospective studies are required to clarify whether these patterns of risk are real, or they are artifacts of unmeasured confounders. Additional data correlating these outcomes with the types of diabetes in pregnancy are also needed to distinguish the effects of pre-gestational vs. gestational diabetes.

  2. Indigenous Manufacturing realization of TWIN Source

    Science.gov (United States)

    Pandey, R.; Bandyopadhyay, M.; Parmar, D.; Yadav, R.; Tyagi, H.; Soni, J.; Shishangiya, H.; Sudhir Kumar, D.; Shah, S.; Bansal, G.; Pandya, K.; Parmar, K.; Vuppugalla, M.; Gahlaut, A.; Chakraborty, A.

    2017-04-01

    TWIN source is two RF driver based negative ion source that has been planned to bridge the gap between single driver based ROBIN source (currently operational) and eight river based DNB source (to be operated under IN-TF test facility). TWIN source experiments have been planned at IPR keeping the objective of long term domestic fusion programme to gain operational experiences on vacuum immersed multi driver RF based negative ion source. High vacuum compatible components of twin source are designed at IPR keeping an aim on indigenous built in attempt. These components of TWIN source are mainly stainless steel and OFC-Cu. Being high heat flux receiving components, one of the major functional requirements is continuous heat removal via water as cooling medium. Hence for the purpose stainless steel parts are provided with externally milled cooling lines and that shall be covered with a layer of OFC-cu which would be on the receiving side of high heat flux. Manufacturability of twin source components requires joining of these dissimilar materials via process like electrode position, electron beam welding and vacuum brazing. Any of these manufacturing processes shall give a vacuum tight joint having proper joint strength at operating temperature and pressure. Taking the indigenous development effort vacuum brazing (in non-nuclear environment) has been opted for joining of dissimilar materials of twin source being one of the most reliable joining techniques and commercially feasible across the suppliers of country. Manufacturing design improvisation for the components has been done to suit the vacuum brazing process requirement and to ease some of the machining without comprising over the functional and operational requirements. This paper illustrates the details on the indigenous development effort, design improvisation to suits manufacturability, vacuum brazing basics and its procedures for twin source components.

  3. Mathematical modeling of the working cycle of oil injected rotary twin screw compressor

    International Nuclear Information System (INIS)

    Seshaiah, N.; Ghosh, Subrata Kr.; Sahoo, R.K.; Sarangi, Sunil Kr.

    2007-01-01

    Oil injected twin-screw air and gas compressors are widely used for medium pressure applications in many industries. Low cost air compressors can be adopted for compression of helium and special gases, leading to significant cost saving. Mathematical analysis of oil injected twin-screw compressor is carried out on the basis of the laws of perfect gas and standard thermodynamic relations. Heat transfer coefficient required for computer simulation is experimentally obtained and used in performance prediction, when the working medium being air or helium. A mathematical model has been developed for calculating the compressor performance and for validating the results with experimental data. The flow coefficients required for numerical simulation to calculate leakage flow rates are obtained from efficiency verses clearance curves. Effect of some of the compressor operating and design parameters on power and volumetric efficiencies have been analyzed and presented

  4. Variant selection during secondary and tertiary twinning in pure titanium

    International Nuclear Information System (INIS)

    Qin, Hong; Jonas, John J.

    2014-01-01

    Three generations of twins were identified by electron backscatter diffraction techniques in pure titanium subjected to uniaxial compression at room temperature. Many primary contraction twins were observed as the initial texture was favourable for their formation. Numerous secondary extension twins formed within the primary contraction twins and some tertiary contraction twins within the secondary extension twins. The orientations of these three generations of twins were determined and their associated Schmid factors (SFs) were calculated. The formation of the twin variants selected in each generation and the absence of certain potential variants are explained by rotating the twinning displacement gradient tensor expressed in the twin system reference frame into the crystal reference frame of the relevant neighbouring grain. The presence of the observed secondary and tertiary twins is accounted for in terms of the ease of imposing the required accommodation strains on their neighbours. The results show that secondary twins can form even with low SFs as long as their accommodation takes place by prismatic or basal glide. However, the formation of certain second and third generation potential high SF twins was impeded when this would have required accommodation by the most difficult deformation mode: pyramidal glide

  5. Separation surgery for total vertical craniopagus twins.

    Science.gov (United States)

    Goh, Keith Y C

    2004-08-01

    A pair of conjoined twins aged 11 months underwent investigations, followed by surgical separation in Singapore General Hospital in April 2001. They were joined at the skull vertex and facing in opposite directions. Radiological investigations including cerebral angiography, magnetic resonance imaging and computerized tomographic scans were performed, leading to the diagnosis of total vertical craniopagus. There were two separate brains, with separate arterial circulations, but with a common superior sagittal sinus. Tissue expanders were inserted in the subgaleal space for 6 months of scalp expansion prior to surgery. Pre-operative planning involved the use of virtual reality equipment and life-sized polymer models of the conjoined skulls and brains. Surgical separation of the twins was achieved after approximately 100 h of operating time, using intraoperative image guidance, microsurgical techniques and intraoperative neurophysiologic monitoring. Reconstruction of the dura, calvarium and scalp was performed with artificial dura, absorbable plates and split skin grafts. Postoperative complications included focal cortical infarction, meningitis, and hydrocephalus. Despite these complications, the twins recovered satisfactorily and were discharged to their home country within 6 months. The 3-month outcome was minor disability in one twin and severe developmental delays in the other. Separation surgery is possible for complex cranially-conjoined twins but requires detailed planning and extensive surgical management.

  6. Yoruba customs and beliefs pertaining to twins.

    Science.gov (United States)

    Leroy, Fernand; Olaleye-Oruene, Taiwo; Koeppen-Schomerus, Gesina; Bryan, Elizabeth

    2002-04-01

    The Yoruba are an important ethnic group mainly occupying Southwestern Nigeria. Mainly for genetic reasons, this very large tribe happens to present the highest dizygotic twinning rate in the world (4.4 % of all maternities). The high perinatal mortality rate associated with such pregnancies has contributed to the integration of a special twin belief system within the African traditional religion of this tribe. The latter is based on the concept of a supreme deity called Olodumare or Olorun, assisted by a series of secondary gods (Orisha) while Yoruba religion also involves immortality and reincarnation of the soul based on the animistic cult of ancestors. Twins are therefore given special names and believed to detain special preternatural powers. In keeping with their refined artistic tradition, the Yoruba have produced numerous wooden statuettes called Ibejis that represent the souls of deceased newborn twins and are involved in elaborate rituals. Among Yoruba traditional beliefs and lore some twin-related themes are represented which are also found in other parts of the world. Basic features of the original Yoruba beliefs have found their way into the religious traditions of descendants of African slaves imported in the West Indies and in South America.

  7. Body odor similarity in noncohabiting twins.

    Science.gov (United States)

    Roberts, S Craig; Gosling, L Morris; Spector, Tim D; Miller, Paul; Penn, Dustin J; Petrie, Marion

    2005-10-01

    There is currently considerable interest in biometric approaches using human odor as a marker of disease or genetic individuality. Body odor is also thought to be used during mate choice to select genetically compatible mates. The idea that body odor reveals information about both genetic identity and genetic similarity is most readily tested by examining odor in twin pairs. However, although this idea can be traced back 130 years to Francis Galton in 1875, most studies using dogs fail to control for shared environmental effects associated with cohabitation. Here we show that odors of identical twins (but not dizygotic twins) can be matched by human sniffers at rates better than chance, even when the twins are living apart. In addition, matching frequencies for identical twin odors were not significantly different from those for duplicate odors from the same individual. These results indicate an important genetic influence on body odor and the potential for developing technologies for human odor printing in relation to underlying genotype.

  8. A Possible Twin: The 1960s Twin Study Revisited/Twin Research: Twin-to-Twin Heart Transplantation; Distinguishing Monozygotic Twins; Twin Conceptions via Oocyte Donation; Factors Affecting Craniofacial Traits/In the Media: Triplet Delivery in the UK; Conjoined Twins and the Concept of Self; Colombian Twin Trainers; Skin Grafting to Save an Identical Co-Twin; Lack of Physical Flaws in Dolly the Cloned Sheep; Possible Conjoined Twins of Opposite-Sex; Passing of the Remaining Twin From the World's Longest Separated Pair.

    Science.gov (United States)

    Segal, Nancy L

    2018-04-01

    This article begins with the story of a 51-year-old Los Angeles, California man, Justin Goldberg, whose daughter caught a glimpse of his striking look-alike at a popular market. Many people have so-called doppelgängers, but this occurrence is especially intriguing - the individual in question, born in New York City in the mid-1960s to an unwed mother, was an adoptee placed by the Louise Wise Adoption Agency. This agency, under the guidance of a prominent psychiatrist, decided to place twins in separate homes. Some of these twin children were part of a controversial child development study that was hidden from them and their parents. Next, recent and current twin research on heart transplantation, distinguishing monozygotic co-twins, twin conceptions via oocyte donation and factors affecting craniofacial traits are summarized. The article concludes with highlights on twins in the media, specifically, a triplet delivery in the United Kingdom, self-concept and consciousness in conjoined twins, Colombian twin trainers, skin grafting to save an identical co-twin, lack of physical flaws in Dolly the cloned sheep, possible opposite-sex conjoined twins, and the passing of the remaining twin from the world's longest separated pair.

  9. Nationwide Twin Birth Weight Percentiles by Gestational Age in Taiwan

    Directory of Open Access Journals (Sweden)

    I-Jan Hu

    2015-10-01

    Conclusion: This is the first nationwide birth weight norm for twins in Taiwan, which is particularly useful for investigation into the predictors and outcomes of altered fetal growth through twin studies in the Taiwanese population.

  10. The antenatal diagnosis of cephalothoracopagus Janiceps conjoined twins.

    Science.gov (United States)

    Ramadani, H M; Johnshrud, N; al Nasser, M; Rayes, O

    1994-02-01

    A case of cephalothoracopagus conjoined twins (Janiceps twins) is presented. The abnormality was detected antenatally by the use of ultrasonography and confirmed postnatally, clinically and by computed tomography (CT scan).

  11. Twin boundaries, interfaces and modulated structures in martensites. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Barsch, G.R.

    1992-09-30

    Theoretical studies were pursued with supporting experimental investigations (In-Tl) on the statics, dynamics, and statistical mechanics of twin boundaries, twin bands, and pretransformation structural modulations in proper and improper ferroelastic martensites.

  12. Twinning dislocation and twin propagation process in a nickel-base single crystal TMS-82 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xianzi; Zhang, Jianxin [Shandong Univ., Jinan (China). Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials; Harada, Hiroshi [National Institute for Materials Science, Ibaraki (Japan)

    2014-03-15

    Thermomechanical fatigue cyclic loading tests have been carried out along the <001> orientation and the formation of twins during thermomechanical fatigue processing has been studied in detail in a nickel-base single crystal TMS-82 superalloy. The twinning dislocation is determined to be 1/6<112> in the γ' phase except for the 1/3<112> dislocation, which operates on every successive {111} plane. The 1/6<112> twinning dislocations can move independently in both γ and γ' phases. Although movement of a single 1/6<112> twining dislocation may destroy the ordering of γ' phase, its existence is rationalized on the basis of crystallographic analysis. The movement of a 1/3<112> dislocation on a single {111} plane will lead to a high-energy stacking sequence of head-to-head of two neighboring {111} layer atoms in the L1{sub 2} structure. Pre-existing dislocations have a significant effect on the growth of deformation twins. In the dislocation-free area, the twin can propagate without any notable impediment to lead to a twin plate with equal width. High dislocation density may hinder the propagation of twins to varying degrees. (orig.)

  13. Low twinning rate and seasonal effects on twinning in a fertile population, the Hutterites

    Science.gov (United States)

    Nonaka, K.; Miura, T.; Peter, K.

    1993-09-01

    This paper analyzes from the mid 18th century to 1987 the birth records of the “Dariusleut,” one of the three subgroups of the Hutterite population. The aim of this study is to describe several aspects of the twinning rate in a fertile population. The overall rate of twinning was 0.90%:103 twins among all 11492 maternities. The rate peaked at the 7th birth order and at the maternal age of 40 years and over. Until the mid 19th century when the Hutterites lived in Russia, the twinning rate was higher (1.5%), and it decreased during the migration period in the second half of the 19th century (0.7%). After the group had settled in the USA and Canada, the population maintained a twinning rate of 1.0% until 1965. After 1965 the rate decreased to 0.7%, partly due to a decline in fertility among women aged 30 years and over. There was a significant seasonal variation: the twinning rate decreased to 0.5% in May July compared to 1.2% for the other three seasons during the years up to 1965 ( P<0.01), while more recent mothers did not show such a seasonal variation. The incidence of twin births in this population seems to have been influenced by environmental factors, which would change their effect seasonally and secularly.

  14. A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model.

    Directory of Open Access Journals (Sweden)

    David J Sharrow

    Full Text Available Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65.

  15. A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model.

    Science.gov (United States)

    Sharrow, David J; Anderson, James J

    2016-01-01

    Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65.

  16. On the theory of twinning plane superconductivity

    International Nuclear Information System (INIS)

    Mishonov, T.M.

    1988-01-01

    The thermodynamic potential of the superconducting layer in the twinning plane (TP) vicinity for the type I superconductors is found. The corrections to the surface tension in powers of the Ginsburg-Landau parameter κ are obtained. The corresponding states law for the supercooling field for the type I twinning plane superconductivity (TPS) is obtained, as well as the critical field law for the type II TPS. A review of experimental and theoretical works on TPS and some similar systems is given. The conditions for the Berezinski-Kosterlitz-Thouless transition for the proximity effect are discussed, as well as the possible mechanisms for the conducting phase transition TPS in Nb and the pinning forces close to the twinning plane. The obtained order parameter distribution can be used for description of the superlattices from normal and superconducting metals as well. 6 figs., 44 refs

  17. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...... plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning....... The sample size in transition is relatively large and easily accessible in experiments, making our understanding of size dependence11, 12, 13, 14, 15, 16, 17 relevant for applications....

  18. Statistics of twinning in strained ferroelastics

    Science.gov (United States)

    Ding, Xiangdong; Aktas, Oktay; Wang, Xiaofei; Li, Suzhi; Zhao, Ziyuan; Zhang, Libo; He, Xiaomei; Lookman, Turab; Saxena, Avadh; Sun, Jun

    2017-10-01

    In this review, we show that the evolution of the microstructure and kinetics of ferroelastic crystals under external shear can be explored by computer simulations of 2D model materials. We find that the nucleation and propagation of twin boundaries in ferroelastics depend sensitively on temperature. In the plastic regime, the evolution of the ferroelastic microstructure under strain deformation maintains a stick-and-slip mechanism in all temperature regimes, whereas the dynamic behavior changes dramatically from power-law statistics at low temperature to a Kohlrausch law at intermediate temperature, and then to a Vogel-Fulcher law at high temperature. In the yield regime, the distribution of jerk energies follows power-law statistics in all temperature regimes for a large range of strain rates. The non-spanning avalanches in the yield regime follow a parabolic temporal profile. The changes of twin pattern and twin boundaries density represent an important step towards domain boundary engineering.

  19. A Danish Twin Study of Schizophrenia Liability

    DEFF Research Database (Denmark)

    Kläning, Ulla; Trumbetta, Susan L; Gottesman, Irving I

    2016-01-01

    We studied schizophrenia liability in a Danish population-based sample of 44 twin pairs (13 MZ, 31 DZ, SS plus OS) in order to replicate previous twin study findings using contemporary diagnostic criteria, to examine genetic liability shared between schizophrenia and other disorders, and to explore...... whether variance in schizophrenia liability attributable to environmental factors may have decreased with successive cohorts exposed to improvements in public health. ICD-10 diagnoses were determined by clinical interview. Although the best-fitting, most parsimonious biometric model of schizophrenia...... liability specified variance attributable to additive genetic and non-shared environmental factors, this model did not differ significantly from a model that also included non-additive genetic factors, consistent with recent interview-based twin studies. Schizophrenia showed strong genetic links to other...

  20. Potency and Characteristics of Bali Cattle Twin Birth

    OpenAIRE

    Utami, Anastasia Sischa Jati; Suyasa, I Nyoman

    2015-01-01

    Cattle twin birth is a rare occurrence that might be due to two factors, natural factors or external interventions such as the use of hormones. This study was aimed to determine to what extent Bali cattle were potential to deliver twin birth. Natural twin birth observation was conducted by survey method and data service while for super ovulation was conducted on 6 cows that never gave birth to twins. The Intervention method used a variety of hormonal preparations started with installing CIDR ...

  1. Twins and politics: political careers and political attitudes / twin research reviews: pair-bonding; facial expressivity in reared apart twins; educating multiples / stories that move and amaze us: a military funeral; a twins' reunion; Egyptian septuplets; rare occupations.

    Science.gov (United States)

    Segal, Nancy L

    2008-12-01

    Twins and twin research are providing fresh insights into the roots of political behavior. This topic is approached from dual perspectives: why some individuals choose to become politicians, and why individuals vary in their political attitudes and interests. Reviews of timely twin studies in the areas of pair-bonding, facial expressivity and education follow. Finally, some extraordinary events in the lives of twins and their families are revealed.

  2. Conjoined twins detected in the first trimester: A review

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2011-12-01

    Full Text Available Conjoined twinning occurs in 1 in 100 sets of monozygotic twins, 1 in 50,000 gestations or 1 in 250,000 live births. With the advent of ultrasound technology, prenatal diagnosis of conjoined twins is possible. This article provides a comprehensive review of conjoined twins detected in the first trimester including fetal gender, maternal age, parity, types of fusion, related ultrasound abnormalities, perinatal outcome and association with assisted reproduction.

  3. Fetal MRI of conjoined twins who switched their relative positions

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, Thierry A.G.M. [University Children' s Hospital, Department of Diagnostic Imaging, Zurich (Switzerland); Johns Hopkins Hospital, Division of Pediatric Radiology, Department of Radiology and Radiological Science, Baltimore, MD (United States); Arulrajah, Sahayini [Johns Hopkins Hospital, Division of Pediatric Radiology, Department of Radiology and Radiological Science, Baltimore, MD (United States); Meuli, Martin [University Children' s Hospital, Department of Surgery, Zurich (Switzerland); Brehmer, Ulrike [University Children' s Hospital, Department of Diagnostic Imaging, Zurich (Switzerland); Beinder, Ernst [University Hospital, Department of Obstetrics, Zurich (Switzerland)

    2010-03-15

    Conjoined twinning is a very rare occurrence with no genetic predisposition. Twisting of conjoined twins around the axis of their connecting tissue bridge, close to the third trimester, has not been previously reported. We describe a unique case of in utero twisting of conjoined omphalopagus twins who survived without any adverse effects. Fetal US and fetal MRI played a vital role in the diagnosis and perinatal management of these twins. (orig.)

  4. The structure of perfectionism: a twin study.

    Science.gov (United States)

    Tozzi, Federica; Aggen, Steven H; Neale, Benjamin M; Anderson, Charles B; Mazzeo, Suzanne E; Neale, Michael C; Bulik, Cynthia M

    2004-09-01

    Perfectionism may be a premorbid risk factor for eating disorders. Evidence of familial transmission suggests features of perfectionism may be genetically determined. This study examines the structure of perfectionism using classical twin design models. Independent (IP) and common (CP) pathway models are used to investigate the extent to which genetic and environmental factors can help to identify and differentiate three behavioral domains of perfectionism as measured by a shortened version of the Multidimensional Perfectionism Scale (MPS) [Frost et al. (1990). Cognit. Ther. Res. 14: 449-468]. Three of the original subscales were included: Personal standards (PS), Doubts about actions (DA), Concern over mistakes (CM). We studied a sample of 1022 paired and unpaired female twins from the Mid-Atlantic Twin Registry. MZ correlations were consistently higher than DZ twin correlations for all three composite subscales. The multivariate independent pathway model provided a better fit to the twin correlations then did the more parsimonious common pathway model suggesting the pattern of familial resemblance for the three subscales is not well characterized by a unidimensional perfectionism factor. CM phenotypic variance was completely accounted for by common heritability influences in both the IP and CP models. Based on the IP model results, there was evidence that PS and CM but not DA shared some common genetic effects, with DA and CM sharing some common environmental factors. These multivariate twin modeling results support conceptualizations of perfectionism as a multidimensional construct. The biometric structural results for the three subscales examined here suggest CM is the core feature of Perfectionism with DA and PS serving as indicators of CM. Although not the best fitting model, the common pathway model estimated this behavioral domain to be isomorphic with the construct of perfectionism. The better fitting independent pathway model provided evidence of non

  5. Urticaria in Monozygotic and Dizygotic Twins

    Directory of Open Access Journals (Sweden)

    Simon Francis Thomsen

    2012-01-01

    Full Text Available Aim. To identify risk factors for urticaria, to determine the relative proportion of the susceptibility to urticaria that is due to genetic factors in an adult clinical twin sample, and to further determine whether the genetic susceptibility to urticaria overlaps with the genetic susceptibility to atopic diseases. Methods. A total of 256 complete twin pairs and 63 single twins, who were selected from sibships with self-reported asthma via a questionnaire survey of 21,162 adult twins from the Danish Twin Registry, were clinically interviewed about a history of urticaria and examined for atopic diseases. Data were analysed with Cox proportional hazards regression and variance components models. Results. A total of 151 individuals (26% had a history of urticaria, whereas 24 (4% had had symptoms within the past year. Female sex, HR=2.09 (1.46–2.99, P=0.000; hay fever, HR=1.92 (1.36–2.72, P=0.000; and atopic dermatitis, HR=1.44 (1.02–2.06, P=0.041 were significant risk factors for urticaria. After adjustment for sex and age at onset of urticaria in the index twin, the risk of urticaria was increased in MZ cotwins relative to DZ cotwins, HR=1.42 (0.63–3.18, P=0.394. Genetic factors explained 45% (16–74%, P=0.005, of the variation in susceptibility to urticaria. The genetic correlation between urticaria and hay fever was 0.45 (0.01–0.89, P=0.040. Conclusions. Susceptibility to urticaria is partly determined by genetic factors. Urticaria is more common in women, and in subjects with hay fever and atopic dermatitis, and shares genetic variance with hay fever.

  6. Marital status and twins' health and behavior: an analysis of middle-aged Danish twins

    DEFF Research Database (Denmark)

    Osler, Merete; McGue, Matt; Lund, Rikke

    2008-01-01

    OBJECTIVE: To disentangle the influences on health of selection processes related to genetic and rearing environmental factors from factors related to marriage benefits. We compared health status among same-sex male and female twin pairs who lived together during childhood and were discordant...... or concordant on adult marital status. METHODS: A cross-sectional survey of a random sample of middle-aged Danish twins was conducted in 1998 to 1999. This study included 1175 same-sex twin pairs (52.5% monozygotic (MZ) and 47.5% dizygotic (DZ)). Data were obtained on adult marital status and on height, body...

  7. Twin heart with a fused atria and separate ventricles in conjoined twins.

    Science.gov (United States)

    Ambar, Sameer Suresh; Halkati, Prabhu C; Patted, Suresh V; Yavagal, St

    2010-07-01

    One of the most interesting congenital malformations is that of conjoined twins. We report echocardiographic features of twin heart in dicephalus, tribrachius, dispinous, thoracoomphalopagus twin. It showed two hearts fused at atrial level. Right-sided heart had single atrial chamber with a single ventricle. A single great vessel, aorta, originated from it. Left-sided heart was well developed with two atria and two ventricles. There was a small mid muscular ventricular septal defect and a small patent ductus arteriosus. Great arteries had normal origins.

  8. Conjoined twins: scientific cinema and Pavlovian physiology.

    Science.gov (United States)

    Krementsov, Nikolai

    2015-01-01

    Through the lens of a 1957 documentary film, "Neural and humoral factors in the regulation of bodily functions (research on conjoined twins)," produced by the USSR Academy of Medical Sciences, this essay traces the entwined histories of Soviet physiology, studies of conjoined twins and scientific cinema. It examines the role of Ivan Pavlov and his students, including Leonid Voskresenkii, Dmitrii Fursikov and Petr Anokhin, in the development of "scientific film" as a particular cinematographic genre in Soviet Russia and explores numerous puzzles hidden behind the film's striking visuals. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  9. Cord entanglement in monoamniotic twin pregnancies

    DEFF Research Database (Denmark)

    Lyndrup, J; Schouenborg, Lars Øland

    1987-01-01

    Monoamniotic twin pregnancy involves a heavy risk of fatal umbilical cord entanglement. Two cases are reported. In the first case, both twins were found dead in the 36th week, and the monoamnionicity was recognized at birth. In the second case, the monoamnionicity was discovered during an ultraso...... an ultrasound examination, and cord entanglement was suspected in the 35th week on the basis of a non-stress test (NST) with variable decelerations. Cesarean section was performed and two healthy children were delivered....

  10. Rainbow correlation imaging with macroscopic twin beam

    Science.gov (United States)

    Allevi, Alessia; Bondani, Maria

    2017-06-01

    We present the implementation of a correlation-imaging protocol that exploits both the spatial and spectral correlations of macroscopic twin-beam states generated by parametric downconversion. In particular, the spectral resolution of an imaging spectrometer coupled to an EMCCD camera is used in a proof-of-principle experiment to encrypt and decrypt a simple code to be transmitted between two parties. In order to optimize the trade-off between visibility and resolution, we provide the characterization of the correlation images as a function of the spatio-spectral properties of twin beams generated at different pump power values.

  11. Challenges in the management of twin pregnancy discordant for ...

    African Journals Online (AJOL)

    Challenges in the management of twin pregnancy discordant for abnormality. CJM Stewart. Abstract. Prenatal diagnosis in the setting of a twin pregnancy is challenging. The frequency of abnormalities is higher in twin than in singleton pregnancies, particularly in monozygotic pregnancies. The finding of an abnormality in ...

  12. Twin pregnancy possibly associated with high semen quality

    DEFF Research Database (Denmark)

    Asklund, Camilla; Jensen, Tina Kold; Jørgensen, Niels

    2007-01-01

    BACKGROUND: Recent studies found an association between a long waiting time to pregnancy (TTP) and reduced probability of twinning and a reduced dizygotic (DZ) twinning rate in subfertile men. However, it remains unsolved whether semen quality is associated with twin offspring. We therefore studied...

  13. Dicephalus dipus tetrabrachius conjoined twins of Zaria: Case report ...

    African Journals Online (AJOL)

    2012-04-20

    Apr 20, 2012 ... One of the most interesting congenital malformations to manage is a conjoined twin. Conjoined twins are rare occurrences in obstetric/pediatric practice. More commonly known as Siamese twins, this phenomenon is shrouded in mystery and considered a curiosity by general public. Current technology is ...

  14. Interaction effects on hydrodynamic characteristics of twin rudders

    NARCIS (Netherlands)

    Liu, J.; Hekkenberg, R.G.

    2016-01-01

    In order to reach the required manoeuvrability, inland vessels often use twin rudders, but the interaction effects are poorly understood. To achieve a proper configuration, this paper applies 2D RANS simulations to analyse the interaction effects on the twin-rudder hydrodynamics. Various twin-rudder

  15. Dicephalus dibrachius dipus conjoined twins in a triplet pregnancy ...

    African Journals Online (AJOL)

    Conjoined twins occurring in a triplet pregnancy is a rare occurrence. We present a case of undiagnosed dicephalic conjoined twins occurring in a multigravida with triple pregnancy delivered by caesarian section. The anatomical and pathologic findings in these twins after their demise are described with a brief review of ...

  16. Twins with omphalocele in Denmark (1970-1989)

    DEFF Research Database (Denmark)

    Bugge, Merete

    2010-01-01

    Seven pairs of twins, two monozygotic (MZ), two dizygotic (DZ), and three like-sex pairs of unknown zygosity are described. The twin pairs were all discordant for omphalocele except for one pair of conjoined twins. The 8 infants with omphalocele represent 3.1% of the 253 infants with omphalocele...

  17. to-twin transfusion after fetoscopic laser surgery

    African Journals Online (AJOL)

    c and Caroline C. Hulsker a. Twin-to-twin transfusion syndrome (TTTS) occurs in 10% of monochorionic twin pregnancies, and can lead to a variety of complications due to imbalanced blood flow across placental vascular communications. In this report, we describe a case of intestinal injury in TTTS after fetoscopic.

  18. Identical twins with “mirror image” anisometropia and esotropia

    Directory of Open Access Journals (Sweden)

    Stanković-Babić Gordana

    2011-01-01

    Full Text Available Introduction. Identical twins account for 0.2% of the world population and 8% of all twins. A “mirror image” variation can be found in 25% of identical twins. Studies of twins assume a special place in human genetics due to the possibility of comparing genetic and other factors. We present two pairs of identical male twins with mirror-image astigmatism and esotropia. Case Outline. The first was a pair of twelve-year old identical twins with “mirror image” myopic astigmatism. The Twin 1 had myopic astigmatism in the right eye, while the Twin 2 was affected by the left eye myopic astigmatism. The second was a pair of six-year old identical twins with esotropia and hypermetropic astigmatism. The Twin 1 had esotropia in the left eye, while the right eye was affected in the Twin 2. Esotropia was surgically corrected. Conclusion. In this study we pointed to the role of genetic factors in the development of refractive error, as well as the type of strabismus. Refraction anomalies (myopia, hypermetropia and astigmatism are complex heterogeneous disorders and ideal for genetic investigation. The knowledge of genetic mechanisms involved in refractive error susceptibility may allow treatment to prevent progression or to further examine gene-environment interactions. We hope that this paper will initiate further investigation of refraction anomalies in twins and future multicentre studies, which, to our knowledge, have not been conducted in our country so far.

  19. Obstetric outcome of twin pregnancies in Jos, Nigeria | Mutihir ...

    African Journals Online (AJOL)

    Obstetric outcome of twin pregnancies in Jos, Nigeria. JT Mutihir, VC Pam. Abstract. Objectives: The objectives of the study were to determine the incidence, maternal and foetal outcome of twin delivery in Jos, Nigeria. Methodology: All consecutive twin deliveries between August 2003 and November 2004 were studied.

  20. Pelvic ventral hernia repair in a pygopagus conjoint twin | Bhullar ...

    African Journals Online (AJOL)

    Pelvic ventral hernia repair in a surviving conjoint twin with multiple congenital anomalies that make surgery a challenge. Conjoint twins are a rare. The incidence is reported to be in the range of 1/50 000 to 1/100 000 live births. Of the conjoint twins, 40% are stillborn and an additional one-third die within 24 h of birth.

  1. Left-handedness in twins: genes or environment?

    NARCIS (Netherlands)

    Orlebeke, J. F.; Knol, D. L.; Koopmans, J. R.; Boomsma, D. I.; Bleker, O. P.

    1996-01-01

    Twin family data can cast light on the longstanding problem about the influences of genes and environment on the etiology of left-handedness. Therefore, hand preference was assessed in 1700 adolescent twin pairs and their parents. Left-handedness (LH) appeared not significantly enhanced among twins

  2. A note on twin-singleton differences in asthma

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; Kyvik, Kirsten Ohm; Backer, Vibeke

    2008-01-01

    Twins constitute a valuable resource for genetic studies of asthma. However, critics argue that twins are 'special' in terms of prenatal environment and upbringing and therefore nonrepresentative. In respect to asthma a small range of studies report differential morbidity in twins compared with s...

  3. Perinatal Mortality Among Twins In Lagos University Teaching ...

    African Journals Online (AJOL)

    Background: Perinatal mortality rate is reported to be higher in twins than in singletons. More than two decades ago, Abudu and Agarin reported a twinning rate of 21.1/1000 maternities and perinatal mortality rate of 142.6/1000 among twins in Lagos. Objective: To determine the current perinatal mortality rate and risk factors ...

  4. Discordant HIV-1 Infection in Dizygotic Twins: Case Report and ...

    African Journals Online (AJOL)

    First-born twins are at a four-fold risk of acquiring HIV infection if delivered by caesarean section. A female second twin delivered by caesarean section presented at the age of 14 months with features of HIV/AIDS. She died four months later of full blown AIDS. The first twin, a male, who was delivered vaginally, ...

  5. Trisomy 13 in monozygotic twins discordant for major congenital anomalies.

    OpenAIRE

    Naor, N; Amir, Y; Cohen, T; Davidson, S

    1987-01-01

    The occurrence of trisomy 13 in twins is very rare. We report a pair of genotypically identical twins with trisomy 13 discordant for major anomalies. This case contributes to the already published data on the contribution of non-genetic factors to the aetiology of congenital malformations in monozygotic twins.

  6. High prevalence of same-sex twins in patients with cloacal exstrophy: Support for embryological association with monozygotic twinning.

    Science.gov (United States)

    Fullerton, Brenna S; Sparks, Eric A; Hall, Amber M; Velazco, Cristine S; Modi, Biren P; Lund, Dennis P; Jaksic, Tom; Hendren, W Hardy

    2017-05-01

    Previous studies have hypothesized that cloacal exstrophy may be caused by errors early in embryological development related to monozygotic twinning. This study reports the prevalence of twins in a large cohort of patients with cloacal exstrophy. Patients with cloacal exstrophy treated 1974-2015 were reviewed for reports of multiple gestation or conjoined twinning. The genetic sex of the patient and their twin, and any mention of anomaly in the twin were recorded. Neither placental exam nor genetic testing results were available to definitively determine zygosity. Of 71 patients, 10 had a live born twin (14%), all of whom were of the same genetic sex as the affected patient. One additional patient's twin suffered intrauterine fetal demise, and another patient had a conjoined heteropagus twin. None of the twins were affected by exstrophy-epispadias complex. The rate of twin birth in this cohort was 4.4-7.7 higher than that reported by the Centers for Disease Control in the general population time period (P<0.001), with a striking preponderance of same-sex pairs. The highly significant prevalence of same-sex twin pairs within this cohort supports the hypothesis that the embryogenesis of cloacal exstrophy may be related to errors in monozygotic twinning. 2b. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Infant mortality in twin pregnancies following in-utero demise of the co-twin

    Directory of Open Access Journals (Sweden)

    Boubakari Ibrahimou

    2015-09-01

    Conclusions: Risks for all mortality types were lower among converted co-twins than their unconverted or same-quantile counterparts. The lower neonatal and higher post-neonatal mortality among black require future research.

  8. Twin-twin transfusion syndrome presenting as polyhydramnios in both fetuses secondary to spontaneous microseptostomy.

    Science.gov (United States)

    Hackney, David N; Khalek, Nahla; Moldenhauer, Julie; Ozcan, Tulin

    2013-10-01

    The presence of polyhydramnios and oligohydramnios is pathognomonic for twin-twin transfusion syndrome (TTTS). However, polyhydramnios of both twins can exist in TTTS in the setting of a septostomy of the dividing membrane. In prior reported cases of dual polyhydramnios TTTS, the septostomy was identified through either ultrasound or fetoscopy thus helping to establish the diagnosis of TTTS with an unusual presentation. The presented case is a set of monochorionic, diamniotic twins who presented initially with dual polyhydramnios. Subsequent ultrasound and clinical and pathologic findings were otherwise consistent with TTTS. Unlike prior reported cases, a septostomy of the dividing membrane was never identified with ultrasound or even on post delivery placental examination. However, microseptostomies were demonstrated due to the transfer of indigo carmine between the amniotic sacs at amniocentesis. Thus in the setting of TTTS concern, the diagnosis should be considered with dual polyhydramnios even if a septostomy cannot be identified.

  9. Nature versus nurture: identical twins and bariatric surgery.

    Science.gov (United States)

    Hagedorn, Judith C; Morton, John M

    2007-06-01

    Genetics and environment both play a role in weight maintenance. Twin studies may help clarify the influence of nature vs nurture in weight loss. We present the largest U.S. experience with monozygotic (MZ) twins undergoing bariatric surgery. We retrospectively reviewed the charts of four sets of MZ twins who underwent Roux-en-Y gastric bypass (RYGBP) surgery and laparoscopic adjustable gastric band (LAGB) placement at three different institutions. BMI and co-morbidities were examined pre- and postoperatively, and laboratory values were recorded. All four sets of twins are female, live together, and have similar professions. Twin cohort 1 had near identical weight loss patterns after open RYGBP surgery in 1996 (preop 146/142 kg; 2 years 82/82; and 10 years 108/107). Twin cohort 1 also both underwent cholecystectomies within the first year postoperatively. Twin cohort 2 underwent laparoscopic RYGBP surgery and also required cholecystectomies in the first postoperative year. Cohort 2 also experienced nearly identical weight loss at 1 year (36.7% vs 37.0% BMI loss). Twin cohort 3 underwent LAGB placement with two different surgeons with differing amounts of weight loss at 6 months (6.5% vs 15.7% BMI loss). Finally, twin cohort 4 underwent laparoscopic RYGBP with 2-year BMI loss of 39% vs 34%. In twin cohort 4, the twin who lost less weight lived apart from her twin and extended family, and her weight loss was less than the twin living with her family. Two sets of MZ twins had identical responses to bariatric surgery. The other two sets of identical twins had differential weight loss results, possibly due to differences in surgical approach and social support. While genetics do exert a strong influence on weight loss and maintenance, this case series demonstrates the potential effect of social support and postoperative management upon postoperative weight loss in the presence of identical genetics.

  10. A genome wide linkage scan for dizygotic twinning in 525 families of mothers of dizygotic twins.

    Science.gov (United States)

    Painter, Jodie N; Willemsen, Gonneke; Nyholt, Dale; Hoekstra, Chantal; Duffy, David L; Henders, Anjali K; Wallace, Leanne; Healey, Sue; Cannon-Albright, Lisa A; Skolnick, Mark; Martin, Nicholas G; Boomsma, Dorret I; Montgomery, Grant W

    2010-06-01

    The tendency to conceive dizygotic (DZ) twins is a complex trait influenced by genetic and environmental factors. To search for new candidate loci for twinning, we conducted a genome-wide linkage scan in 525 families using microsatellite and single nucleotide polymorphism marker panels. Non-parametric linkage analyses, including 523 families containing a total of 1115 mothers of DZ twins (MODZT) from Australia and New Zealand (ANZ) and The Netherlands (NL), produced four linkage peaks above the threshold for suggestive linkage, including a highly suggestive peak at the extreme telomeric end of chromosome 6 with an exponential logarithm of odds [(exp)LOD] score of 2.813 (P = 0.0002). Since the DZ twinning rate increases steeply with maternal age independent of genetic effects, we also investigated linkage including only families where at least one MODZT gave birth to her first set of twins before the age of 30. These analyses produced a maximum expLOD score of 2.718 (P = 0.0002), largely due to linkage signal from the ANZ cohort, however, ordered subset analyses indicated this result is most likely a chance finding in the combined dataset. Linkage analyses were also performed for two large DZ twinning families from the USA, one of which produced a peak on chromosome 2 in the region of two potential candidate genes. Sequencing of FSHR and FIGLA, along with INHBB in MODZTs from two large NL families with family specific linkage peaks directly over this gene, revealed a potentially functional variant in the 5' untranslated region of FSHR that segregated with the DZ twinning phenotype in the Utah family. Our data provide further evidence for complex inheritance of familial DZ twinning.

  11. Characterization of the matrix-twin interface of a (1 0 -1 2) twin during growth

    Czech Academy of Sciences Publication Activity Database

    Ostapovets, Andriy; Serra, A.

    2014-01-01

    Roč. 94, č. 25 (2014), s. 2827-2839 ISSN 1478-6443 R&D Projects: GA MŠk(CZ) EE2.3.30.0063 Grant - others:Catalan Government(ES) AGAUR2014SGR 1644; Spanish Secretariat of Research , Development and Innovation (ES) FIS2012-39433-C02-02 Institutional support: RVO:68081723 Keywords : twinning * twin boundaries * disconnections Subject RIV: BM - Solid Matter Physics ; Magnetism; BM - Solid Matter Physics ; Magnetism (FZU-D)

  12. Comparison of academic performance of twins and singletons in adolescence

    DEFF Research Database (Denmark)

    Christensen, Kaare; Petersen, Inge; Skytthe, Axel

    2006-01-01

    OBJECTIVES: To determine whether twins in recent cohorts show similar academic performance in adolescence to singletons and to test the effect of birth weight on academic performance in twins and singletons. DESIGN: Follow-up study. SETTING: Denmark. PARTICIPANTS: All twins (n=3411) and a 5% random...... increase in birth weight. CONCLUSIONS: Although older cohorts of twins have been found to have lower mean IQ scores than singletons, twins in recent Danish cohorts show similar academic performance in adolescence to that of singletons. Birth weight has a minimal effect on academic performance in recent...

  13. The importance of secondary and ternary twinning in compressed Ti

    International Nuclear Information System (INIS)

    Tirry, W.; Nixon, M.; Cazacu, O.; Coghe, F.; Rabet, L.

    2011-01-01

    Twin formation during uniaxial compression of high-purity α-Ti at room temperature is investigated for both quasi-static and dynamic conditions using electron backscatter diffraction techniques. The initial texture is favorable for {101-bar 2} twinning, yet it is observed that secondary and ternary twins occur for both strain rates, showing a higher propensity in the dynamic case. While secondary twins may explain the difference in texture change and strain hardening between the two loading conditions, the ternary twins mainly contribute to grain fractioning.

  14. Prenatal Sonographic Diagnosis of Acardiac Twins

    International Nuclear Information System (INIS)

    Kim, Jeong Ah; Song, Mi Jin

    2006-01-01

    This study was performed to present the prenatal sonographic findings and the associated abnormalities of acardiac twins. Seven cases of acardiac twins were reviewed retrospectively. Prenatal ultrasonography was performed in all patients at a gestational age between 12 and 27 weeks (mean 17.6 weeks). Autopsy was performed in four cases. The sonographic and autopsy findings were reviewed to report the associated abnormalities of the acardiac and donor fetuses. The diagnosis of acardiac twins was made on the basis of ultrasonography (n=6) or autopsy (n=1). The associated abnormalities of the acardiac fetuses were single umbilical artery (SUA) (n=5), abdominal wall defect (n=4), club feet (n=4), scoliosis (n=1), cleft lip and palate (n=1), digital anomaly (n=1), and umbilical cord cyst (n=1). In four of the donor fetuses, sonographic abnormalities were found. Autopsy was performed in three of the four cases to reveal hydropic change (n=2), diaphragmatic hernia (n=1) and multiple structural abnormalities of interventricular septal defect, polydactyly, club feet and SUA (n=1). Intrauterine fetal death occurred in five donors and follow-up was lost in the remaining two. Meticulous sonography enables the diagnosis of acardiac twins at an early gestational age and can reveal the associated abnormalities of the donor fetus as well as the acardiac fetus

  15. Hyperpolarizability studies of some nonconjugated twin donor ...

    Indian Academy of Sciences (India)

    Administrator

    Nonlinear optics; oscillator strength; optical gap; polarizability. 1. Introduction. The design of materials with large ... strength and optical gaps of the twin donor acceptor sys- tems by varying the number of alkyl groups .... The microscopic first hyperpolarizability, β is a 3rd rank tensor, which has 27 tensor components.

  16. Identical Twin Primigravid Sisters -Spontaneous Labour and ...

    African Journals Online (AJOL)

    We report 2 cases of identical twin sisters, the older sibling getting married 14 months earlier but both got pregnant for their first child at about the same time and were managed by the same Obstetrician and fell into spontaneous labour within a few hours of each other. Both were delivered by emergency caesarean section ...

  17. Managing a Live Advanced Abdominal Twin Pregnancy

    African Journals Online (AJOL)

    examination revealed a closed, uneffaced, firm and posterior ... Advanced abdominal pregnancies with live twin fetuses are extremely rare and are misdiagnosed ... operating room. Leaving the placenta in situ is the best way to deal with abdominal pregnancy, based on previous experience and review of the literature.

  18. INTEGRATED TWIN TOWERS DAN ISLAMISASI ILMU

    Directory of Open Access Journals (Sweden)

    Syaifuddin Syaifuddin

    2013-05-01

    Full Text Available This paper shows some idea as follows: First, integrated design of the Twin Towers as the changing action from IAIN to UIN Sunan Ampel. The religion and general knowledge’s position of Twin Towers’ integrated design is not mixed into one, but it works individually, and at the certain time are united in mutual dialogue. Second, Islamize design is done in order to criticize the general knowledge which has western sources and are secular, materialistic, and individualistic. In the process to Islamize the knowledge, Islamic knowledge tries to intervene the general knowledge in order to filter it so the knowledge will be Islamized. Consequently, to Islamize knowledge is to give an Islamic concept into general knowledge. Third, there are the similarities and differences between integrated design knowledge based on Islamic knowledge and integrated Twin Towers. The difference is in its epistemology process. The similarity is in the curriculum (ontology and objective (axiology. In the curriculum, the examined knowledge is religion and general knowledge. While the objective, Islamize knowledge and integrated Twin Towers aims to integrate religion and general knowledge, to dialogue, to communicate, and to synergy, so it can be a knowledge which is intact-integral-integrative.

  19. Prenatal Sonographic Diagnosis of Acardiac Twins

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Ah; Song, Mi Jin [Cheil General Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2006-09-15

    This study was performed to present the prenatal sonographic findings and the associated abnormalities of acardiac twins. Seven cases of acardiac twins were reviewed retrospectively. Prenatal ultrasonography was performed in all patients at a gestational age between 12 and 27 weeks (mean 17.6 weeks). Autopsy was performed in four cases. The sonographic and autopsy findings were reviewed to report the associated abnormalities of the acardiac and donor fetuses. The diagnosis of acardiac twins was made on the basis of ultrasonography (n=6) or autopsy (n=1). The associated abnormalities of the acardiac fetuses were single umbilical artery (SUA) (n=5), abdominal wall defect (n=4), club feet (n=4), scoliosis (n=1), cleft lip and palate (n=1), digital anomaly (n=1), and umbilical cord cyst (n=1). In four of the donor fetuses, sonographic abnormalities were found. Autopsy was performed in three of the four cases to reveal hydropic change (n=2), diaphragmatic hernia (n=1) and multiple structural abnormalities of interventricular septal defect, polydactyly, club feet and SUA (n=1). Intrauterine fetal death occurred in five donors and follow-up was lost in the remaining two. Meticulous sonography enables the diagnosis of acardiac twins at an early gestational age and can reveal the associated abnormalities of the donor fetus as well as the acardiac fetus

  20. Prenatal diagnosis of chorionicity in twins.

    LENUS (Irish Health Repository)

    Hassan, T

    2012-02-01

    The aim of this audit was to assess the accuracy of transabdominal ultrasound scan in predicting chorionicity in twin pregnancies in our unit. The presence or absence of lambda sign, T-sign, dividing membrane thickness and number of placentae were used to determine chorionicity. We retrospectively analysed these antenatal markers in 268 sets of twins delivered over a 5 year period and compared it with the postpartum placental histology and neonatal gender. Of 268 twin deliveries, 204 (76%) had both chorionicity and placental histology to compare. 67 of 84 (80%) were correctly diagnosed antenatally as monochorionic and 137 of 151 (91%) as dichorionic. In 31 cases (15%) the ultrasound diagnosis of chorionicity didn\\'t match placental histology. Seventeen were thought to be monochorionic antenatally but were confirmed dichorionic on placental histology. Overall chorionicity was correctly diagnosed in 171\\/204 (84%) using transabdominal ultrasound scan (USS) in all trimesters. However the sensitivity and specificity of USS was much higher for dichorionic twins when carried out before 14 weeks of gestation.

  1. Monozygotic twins of different apparent sex

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Yukifumi; Fujino, Nobuyuki; Sato, Yoshiaki; Matsunobu, Akira; Tadokoro, Mamoru [Sagamihara Kyodo Hospital (Japan); Akane, Atsushi [Kansai Medical College, Osaka (Japan); Matsuura, Nobuo; Maeda, Tohru [Kitasato Univ. (Japan); Nakahori, Yutaka; Nakagome, Yasuo [Univ. of Tokyo (Japan)

    1994-10-15

    We report on twins of unlike sex who shared a 45,X/46,X, +mar karyotype. The mar chromosome was found to be Yq- by DNA analysis. Marker studies, including 8 VNTR loci, yielded a probability of monozygosity of 0.99999996. 16 refs., 1 fig., 1 tab.

  2. Parapagus conjoined twins: Complicated anatomy precludes separation

    Directory of Open Access Journals (Sweden)

    Singhal Arbinder

    2006-01-01

    Full Text Available A parapagus set of male conjoined twins was brought to our institution at 12 h after birth. An extensive sharing of the abdominal viscera (single liver, hindgut, abdominal aorta, pelvis (single rectum and anus, genitalia (one set and vertebral column was found. The surgical separation was not considered due to medical and ethical issues.

  3. Confluent hepatic fibrosis in monozygotic twins

    International Nuclear Information System (INIS)

    Ooi, C.G.C.; Peh, W.C.G.; Chan, K.L.; Saing Htut; Ngan, H.

    1999-01-01

    The MRI and CT features of confluent hepatic fibrosis (CHF) are reported in two 6-year-old-twins. This is the first case report in children of this little known entity, which may mimic mass lesions, and the first to describe an association of CHF with anti-tuberculous drugs

  4. pregnancy metabolism In . tWIn

    African Journals Online (AJOL)

    .ficant differences in venous blood sugar values or insulin responses were found between singleton and twin pregnancies. S Atr Med J 1983; 63: 53&-540. It is well known that pregnancy is associated with alterations in carbohydrate metabolism. These changes are best reflected by blood glucose and insulin patterns.

  5. Gleanings from Identical Twins Studying Science.

    Science.gov (United States)

    Mascazine, John R.

    This paper explains and summarizes the results of a study that investigated the ways in which monozygotic (identical) and dizygotic (fraternal) twins learn. Their individual learning style elements were specifically investigated according to the Dunn and Dunn model. This paper discusses the themes, unique needs, and characteristics monozygotic…

  6. Twinning of amphibian embryos by centrifugation

    Science.gov (United States)

    Black, S. D.

    1984-01-01

    In the frog Xenopus laevis, the dorsal structures of the embryonic body axis normally derive from the side of the egg opposite the side of sperm entry. However, if the uncleaved egg is inclined at lg or centrifuged in an inclined position, this topographic relationship is overridden: the egg makes its dorsal axial structures according to its orientation in the gravitational/centrifugal field, irrespective of the position of sperm entry. Certain conditions of centrifugation cause eggs to develop into conjoined twins with two sets of axial structures. A detailed analysis of twinning provided some insight into experimental axis orientation. First, as with single-axis embryos, both axes in twins are oriented according to the direction of centrifugation. One axis forms at the centripetal side of the egg and the other forms at the centrifugal side, even when the side of sperm entry is normal to the centrifugal force vector. Second, if eggs are centrifuged to give twins, but are inclined at lg to prevent post-centrifugation endoplasmic redistributions, only single-axis embryos develop. Thus, a second redistribution is required for high-frequency secondary axis formation. This can be accomplished by lg (as in the single centrifugations) or by a second centrifugation directed along the egg's animal-vegetal axis.

  7. Twin hub network : Identificatie van kansrijke netwerken

    NARCIS (Netherlands)

    Kreutzberger, E.D.; Konings, J.W.; Macharis, C.; Meers, D.

    2014-01-01

    Twin hub network gaat over de bundeling rail container stromen van en naar de zeehavens Rotterdam en Antwerpen en van kleinere zeehavens in de range Duinkerken – Amsterdam. Door de bundeling moet het mogelijk worden om grotere treinladingen en/of hogere treinfrequenties te organiseren en meer inland

  8. Reflectance spectrometry of placental vessels in cases of twin-twin transfusion syndrome: experiments and modeling

    Science.gov (United States)

    Lines, Collin; Kim, Oleg; McMurdy, John; Luks, Francois; Alber, Mark; Crawford, Greg

    2013-03-01

    A stochastic photon transport model in multilayer skin tissue combined with reflectance spectroscopy measurements is used to study placental vessels in cases of twin-twin transfusion syndrome (TTTS). TTTS occurs in about 12% of monozygotic (identical) twin pregnancies wherein flow within placental vessels linking the twins together becomes unbalanced, leading to dual mortality. Endoscopic laser ablation can halt the syndrome by occluding the anastomoses connecting the two fetuses. The objective of this study is to develop a technique to determine hemoglobin (Hb) content through spectral analysis of diffuse reflectance spectra of placental vessels to aid in identification of the anastomoses. Previous work by researchers at Brown University has shown that the reflectance spectra of the donor twin and recipient twin are considerably different in the wavelengths for Hb absorbance. This presentation will give preliminary results for a Monte Carlo model adapted to fit the physiology of the placenta that can be used to quantitative determine the Hb levels. The reflectance spectra of the vessels are simulated for different values of Hb as well oxygenation and water concentration with the vessel and placental mass. The preliminary results will be shown to be in good approximation with the prior experimental data. The combination of modeling with spectroscopic measurement will provide a new tool for detailed prenatal study.

  9. Conjoined twins – role of imaging and recent advances

    Directory of Open Access Journals (Sweden)

    Rishi Philip Mathew

    2017-12-01

    Full Text Available Introduction: Conjoined twins are identical twins with fused bodies, joined in utero. They are rare complications of monochorionic twinning. The purpose of this study is to describe the various types of conjoined twins, the role of imaging and recent advances aiding in their management. Material and methods: This was a twin institutional study involving 3 cases of conjoined twins diagnosed over a period of 6 years from 2010 to 2015. All the 3 cases were identified antenatally by ultrasound. Only one case was further evaluated by MRI. Results: Three cases of conjoined twins (cephalopagus, thoracopagus and omphalopagus were accurately diagnosed on antenatal ultrasound. After detailed counseling of the parents and obtaining written consent, all the three cases of pregnancy were terminated. Delivery of the viable conjoined twins was achieved without any complications to the mothers, and all the three conjoined twins died after a few minutes. Conclusion: Ultrasound enables an early and accurate diagnosis of conjoined twins, which is vital for obstetric management. MRI is reserved for better tissue characterization. Termination of pregnancy when opted, should be done at an early stage as later stages are fraught with problems. Recent advances, such as 3D printing, may aid in surgical pre-planning, thereby enabling successful surgical separation of conjoined twins.

  10. Time trends in the natural dizygotic twinning rate.

    Science.gov (United States)

    Derom, Catherine; Gielen, Marij; Peeters, Hilde; Frijns, Jean-Pierre; Zeegers, Maurice P A

    2011-08-01

    The natural dizygotic (DZ) twinning rate has been proposed as a reliable and useful measure of human fecundity, if adjusted for maternal age at twin birth. The aim of this study was to analyze age-adjusted trends in natural DZ twinning rates over the past 40 years using data from the 'East Flanders Prospective Twin Survey (EFPTS)'. This study involved 4835 naturally conceived twin pregnancies between 1969 and 2009 from the population-based Belgian 'EFPTS'. Age-adjusted trends in the incidence of natural DZ twin pregnancies were calculated using a generalized linear model with Poisson distribution. Both the natural DZ twinning rates and maternal age at twin birth increased in a linear fashion from 1969 to 2009. When age-adjusted, we found that the trend in the natural DZ twinning rate was stable during the whole time period. According to our population-based data and after age-adjustment, a stable natural DZ twinning rate could be observed over the last four decades. Under the assumption that the spontaneous DZ twinning rate is a sensor of fecundity, this indicates a stable 'high' fecundity for this population.

  11. Conjoined twins - role of imaging and recent advances.

    Science.gov (United States)

    Mathew, Rishi Philip; Francis, Swati; Basti, Ram Shenoy; Suresh, Hadihally B; Rajarathnam, Annie; Cunha, Prema D; Rao, Sujaya V

    2017-12-01

    Conjoined twins are identical twins with fused bodies, joined in utero. They are rare complications of monochorionic twinning. The purpose of this study is to describe the various types of conjoined twins, the role of imaging and recent advances aiding in their management. This was a twin institutional study involving 3 cases of conjoined twins diagnosed over a period of 6 years from 2010 to 2015. All the 3 cases were identified antenatally by ultrasound. Only one case was further evaluated by MRI. Three cases of conjoined twins (cephalopagus, thoracopagus and omphalopagus) were accurately diagnosed on antenatal ultrasound. After detailed counseling of the parents and obtaining written consent, all the three cases of pregnancy were terminated. Delivery of the viable conjoined twins was achieved without any complications to the mothers, and all the three conjoined twins died after a few minutes. Ultrasound enables an early and accurate diagnosis of conjoined twins, which is vital for obstetric management. MRI is reserved for better tissue characterization. Termination of pregnancy when opted, should be done at an early stage as later stages are fraught with problems. Recent advances, such as 3D printing, may aid in surgical pre-planning, thereby enabling successful surgical separation of conjoined twins.

  12. Thai Twin Registry: description of the initial stage.

    Science.gov (United States)

    Nanakorn, Somsong; Chusilp, Kusuma; Kutanan, Wibhu

    2013-02-01

    The present study describes the initial phase of the Thai Twin Registry (TTR) in Khon Kaen University, a pioneer research university located in the Northeast of Thailand. The initial steps of the study included the analysis of dermatoglyphic information in Thai twins for answering the research question: Are monozygotic (MZ) and dizygotic (DZ) twins different in dermatoglyphic variables? Subjects were 212 twin pairs (131 MZ and 81 [corrected] DZ), consisting of 155 males and 269 females. Four types of fingerprint pattern (FP) - that is, arch, radial loop, ulnar loop, and whorl - were classified and analyzed and compared between MZ and DZ twins. The arch radial loop and whorl frequencies differ between MZ and DZ twins. When comparing FP in each finger, only the right little finger shows a statistically different FP, while the FP similarity average from 10 homologous fingers of co-twins was greater in MZ than DZ twins. By using the Area Under the Receiver Operating Characteristic curve analysis, the MZ twins could be differentiated from DZ twins by the FP similarity. Summarizing, this valuable report about TTR was conducted by analysis of FP data, which indicated that the MZ and DZ twins exhibited FP pattern and FP similarity differences. Other dermatoglyphic studies of the existing FP database, such as finger ridge count, finger ridge density, and minutia, will be considered for ongoing research at the TTR.

  13. A twin study of personality disorders.

    Science.gov (United States)

    Torgersen, S; Lygren, S; Oien, P A; Skre, I; Onstad, S; Edvardsen, J; Tambs, K; Kringlen, E

    2000-01-01

    No twin study has previously investigated the whole range of personality disorders (PDs) recorded by interviews. Based on twin and patient registries, 92 monozygotic (MZ) and 129 dizygotic (DZ) twin pairs were interviewed with the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II). Observed prevalence rates from a normal population study of more than 2,000 individuals were used in combination with data from the present study to generate statistics assumed to be valid for a normal twin population, and these statistics were used for structural equation modeling. The best-fitting models had a heritability of .60 for PDs generally, .37 for the eccentric (A) cluster, .60 for the emotional (B) cluster, and .62 for the fearful (C) cluster. Among the specific PDs, the heritability appeared to be .79 for narcissistic, .78 for obsessive-compulsive, .69 for borderline, .67 for histrionic, .61 for schizotypal, .57 for dependent, .54 for self-defeating, .29 for schizoid, .28 for paranoid, and .28 for avoidant PDs. The best-fitting models never included shared-in-families environmental effects. However, a model with only shared familial and unique environmental effects could not be ruled out for dependent PD. Shared familial environmental effects may also influence the development of any PD and borderline PD. Passive-aggressive PD did not seem to be affected by genes or family environment at all. The low occurrence of antisocial PD in the twin sample precluded any model for this disorder. PDs seem to be more strongly influenced by genetic effects than almost any axis I disorder, and more than most broad personality dimensions. However, we observed a large variation in heritability among the different PDs, probably partly because of a moderate sample size and low prevalence of the specific disorders.

  14. Prospective risk of fetal death in uncomplicated monochorionic twins.

    LENUS (Irish Health Repository)

    Farah, Nadine

    2012-03-01

    A retrospective cohort study was carried out in a university teaching hospital to determine the prospective risk of unexpected fetal death in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies after viability. All MCDA twins delivered at or after 24 weeks\\' gestation from July 1999 to July 2007 were included. Pregnancies with twin-twin transfusion syndrome, growth restriction, structural abnormalities, or twin reversed arterial perfusion sequence were excluded. Of the 144 MCDA twin pregnancies included in our analysis, the risk of intrauterine death was 4.9%. The prospective risk of unexpected intrauterine death was 1 in 43 after 32 weeks\\' gestation and 1 in 37 after 34 weeks\\' gestation. Our results demonstrate that despite close surveillance, the unexpected intrauterine death rate in uncomplicated MCDA twin pregnancies is high. This rate seems to increase after 34 weeks\\' gestation, suggesting that a policy of elective preterm delivery warrants evaluation.

  15. Hematological disorders at birth in complicated monochorionic twins.

    Science.gov (United States)

    Verbeek, Lianne; Slaghekke, Femke; Sueters, Marieke; Middeldorp, Johanna M; Klumper, Frans J; Haak, Monique C; Oepkes, Dick; Lopriore, Enrico

    2017-06-01

    Monochorionic twins are at risk of severe complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS) and acute peripartum TTTS. The pathophysiology is based on inter-twin blood transfusion through placental vascular anastomoses. Areas covered: This review focuses on the incidence, management and outcome of neonatal hematological complications at birth in TTTS, TAPS and acute peripartum TTTS. Expert commentary: Hematological disorders are often present at birth in monochorionic twins and include acute or chronic anemia, polycythemia and thrombocytopenia. Routine measurement of complete blood counts in all complicated monochorionic twins is strongly recommended. Increased awareness on these disorders and correct diagnostic tests will lead to prompt and adequate management at birth.

  16. Structures and growth textures of Japanese twin boundaries in quartz

    Science.gov (United States)

    Momma, K.; Nagase, T.; Kudoh, Y.; Kuribayashi, T.

    2008-12-01

    Growth textures and atomic configurations of Japanese twin boundaries in quartz were studied by the observation of natural samples and by computational simulations. Samples used in this study are collected from Narushima, Nagasaki Prefecture, Japan. The samples were first polished, and then etched by hydrofluoric acid for several minutes. The etched figures were observed by phase-contrast reflection microscopy and scanning electron microscopy. From these observations, high concentration of Brazil twin lamellae is found near the composition plane of Japanese twin. Observations of cathode luminescence images reveal that the development of Brazil twin lamellae at {112×2} composition plane of Japanese twin is directly related to the preferential growth of Japanese twin along the composition plane. Atomic configurations at {112×2} composition planes of Japanese twin were simulated by using molecular dynamics simulations and the energy minimization method. The simulated structures proved that {112×2} or {1×1×22} composition planes are the only composition planes that do not introduce unsatisfied bonding between Si and O atoms. When the composition plane is different from these planes, some kind of defect structures, like dislocations, are inevitably introduced. In the case of Brazil twin, screw dislocations are also known to be incorporated where orientation of Brazil twin boundary changes from one orientation to another. On the other hand, in the case where Brazil twin boundaries intersect with {112×2} composition planes of Japanese twin, we found that structures are kept coherently without any unsatisfied bonding. This result means that {112×2} composition planes of Japanese twin are the crystallographic sites having more than one possible stacking structures. Observations in this study indicate that {112×2} composition plane of Japanese twin serves as a source of Brazil twin during the course of crystal growth.

  17. The effect of chorionicity and twin-to-twin delivery time interval on short-term outcome of the second twin

    DEFF Research Database (Denmark)

    Hjortø, Sofie; Nickelsen, Carsten; Petersen, Janne

    2013-01-01

    found no difference in the decrease of pH (p = 0.912) and Apgar (p = 0.609) in relation to increasing time interval. Neonatal unit (NICU) admissions did not differ (p = 0.167). Apgar ≤ 7 (p Apgar...... ≤ 7 and second twin pH ≤ 7.00 (p = 0.003) increased second twin risk of NICU admission. Conclusions: Increasing delivery interval was associated with a significant decrease in pH and Apgar, but there was no difference between MC and DC twins. Low Apgar of the first twin increased the risk of second...

  18. Dizygotic monochorionic twin pregnancy conceived following intracytoplasmic sperm injection treatment and complicated by twin-twin transfusion syndrome and blood chimerism

    DEFF Research Database (Denmark)

    Ekelund, Charlotte Kvist; Skibsted, L.; Søgaard, Kirsten

    2008-01-01

    and zygocity determination were performed on amniotic fluid and showed the twins to be dizygotic with normal female and male karyotypes. There were clinical and sonographic signs of twin-twin transfusion syndrome (TTTS), and Cesarean delivery was performed at 32 weeks' gestation. At birth the twins were...... phenotypically a normal male and a normal female. Histology of the placenta showed it to be monochorionic diamniotic. Blood chimerism was found postnatally as both infants had the karyotypes 46,XX[13]/46,XY[17]. Chimerism was not found in cells from a buccal swab at 6 months of age. This is one of only a few...

  19. 'Twin2twin' an innovative method of empowering midwives to strengthen their professional midwifery organisations.

    Science.gov (United States)

    Cadée, Franka; Perdok, Hilde; Sam, Betty; de Geus, Myrte; Kweekel, Liselotte

    2013-10-01

    midwives need professional support from a national midwifery organisation to be able to provide the services that are by regulatory mechanisms and accreditation expected of them. Not all midwives in the world are united in a professional organisation. The aim of this project was to strengthen the midwifery organisations of Sierra Leone and the Netherlands. During the process of the project it was realised that the development of a platform of exchange at organisational level would be enhanced by introducing personal exchange between individual midwives. In response to this new insight the original project plan was adjusted by incorporating the twin2twin method. twin2twin is a feminist methodology of mutual exchange between twenty pairs of midwives from different organisations (in this case Sierra Leone and the Netherlands). The method can be distinguished by 10 specific steps. It was developed, used and (re)evaluated through focus group discussions, storytelling and written evaluations. twinning of organisations was strengthened by adding a human component to the process. With the use of the 'twin2twin' method, midwives were encouraged to invested in a professional and personal bond with their 'twin sister'. This bond was independent and went beyond the relatively short four year project period. Through personal engagement and mutual exchange of knowledge and skills, midwives empowered each other to build and strengthen their midwifery organisations both in Sierra Leone and the Netherlands. (Empowerment refers to the expansion in people's ability to make strategic life choices in a context where this ability was previously denied to them (Narayan, 2005); organisational empowerment includes processes and structures that enhance members' skills and provides them with the mutual support necessary to effect community level change (Zimmerman, 1995).). despite challenges we are convinced that twin2twin can be of additional benefit for the success of other projects

  20. Monozygotic triplets: concordance and discordance for cleft lip and palate / twin research reviews: depression in mothers of multiples; depression in mothers and fathers of ART conceived multiples; epigenetic differences in monozygotic twins; congenital anomalies in surviving twins / headlines x two: twin Chefs; the world's largest twin registry; twin table tennis champions.

    Science.gov (United States)

    Segal, Nancy L

    2009-08-01

    A review of twin research on cleft lip and palate is presented. This information is accompanied by a look at the lives of young monozygotic (MZ) male triplets concordant for cleft lip, but discordant for the type and placement of the cleft and for the presence of cleft palate. Research on depression in mothers and fathers of twins conceived naturally and by artificial reproductive techniques follows. Current findings and implications of epigenetic differences in MZ twins are also summarized. Interesting life history events surrounding MZ twin chefs and table tennis players, as well as plans to construct the world's largest twin registry, are presented in the final section.

  1. Long hole waterjet drilling for gas drainage

    Energy Technology Data Exchange (ETDEWEB)

    Matt Stockwell; M. Gledhill; S. Hildebrand; S. Adam; Tim Meyer [CMTE (Australia)

    2003-04-01

    In-seam drilling for gas drainage is now an essential part of operations at many Australian underground coalmines. The objective of this project is to develop and trial a new drilling method for the accurate and efficient installation of long inseam boreholes (>1000 metres). This involves the integration of pure water-jet drilling technology (i.e. not water-jet assisted rotary drilling) developed by CMTE with conventional directional drilling technology. The system was similar to conventional directional drilling methods, but instead of relying on a down-hole-motor (DHM) rotating a mechanical drill bit for cutting, high pressure water-jets were used. The testing of the system did not achieve the full objectives set down in the project plan. A borehole greater than 1000 metres was not achieved. The first trial site had coal that was weathered, oxidized and dry. These conditions significantly affected the ability of the drilling tool to stay 'in-seam'. Due to the poor conditions at the first trial, many experimental objectives were forwarded to the second field trial. In the second trial drilling difficulties were experienced, this was due to the interaction between the confinement of the borehole and the dimensions of the down hole drilling assembly. This ultimately reduced the productivity of the system and the distance that could be drilled within the specified trial periods. Testing in the first field trial did not show any indication that the system would have this difficulty.

  2. Neurodevelopmental outcome in twin anemia-polycythemia sequence after laser surgery for twin-twin transfusion syndrome.

    Science.gov (United States)

    Slaghekke, F; van Klink, J M M; Koopman, H M; Middeldorp, J M; Oepkes, D; Lopriore, E

    2014-09-01

    To evaluate the long-term neurodevelopmental outcome in children who developed twin anemia-polycythemia sequence (TAPS) after fetoscopic laser surgery for twin-twin transfusion syndrome (TTTS). Neurological, motor and cognitive development was assessed in a consecutive cohort of TTTS survivors treated with laser surgery between 2004 and 2011 and complicated by post-laser TAPS. Primary outcome was neurodevelopmental impairment, a composite outcome including any of the following: cerebral palsy, bilateral deafness, blindness, severe motor and/or cognitive developmental delay (>2 SD below the mean). A risk analysis on cognitive outcome was performed. During the study period, 33/306 (11%) monochorionic twin pairs developed TAPS after laser surgery for TTTS. Survival was 53/66 (80%). Long-term outcome was assessed in 47/53 (89%) children. The incidence of neurodevelopmental impairment was 4/47 (9%), occurring in one donor (1/20; 5%) and three recipients (3/27; 11%) (P=0.63). Mild-to-moderate cognitive delay, i.e. scores below 85, was detected in 8/47 (17%) children. Risk factors for low cognitive scores were low gestational age at birth (P=0.02) and low birth weight (Pcognitive scores were detected in the subgroup of TAPS survivors treated with intrauterine transfusion (median score, 82.5). Neurodevelopmental impairment and cognitive delay were found in almost one in five children surviving post-laser TAPS. Better treatment and, ideally, prevention of this complication after laser treatment for TTTS is urgently needed. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

  3. Do assisted-reproduction twin pregnancies require additional antenatal care?

    Science.gov (United States)

    Jauniaux, E; Ben-Ami, I; Maymon, R

    2013-02-01

    Iatrogenic twinning has become the main side-effect assisted reproduction treatment. We have evaluated the evidence for additional care that assisted-reproduction twins may require compared with spontaneous twins. Misacarriages are increased in women with tubal problems and after specific treatments. Assisted-reproduction twin pregnancies complicated by a vanishing twin after 8 weeks have an increased risk of preterm delivery and of low and very low birthweight compared with singleton assisted-reproduction pregnancies. Monozygotic twin pregnancies occur at a higher rate after assisted reproduction treatment and are associated with a higher risk of perinatal complications. The incidence of placenta praevia and vasa praevia is increased in assisted-reproduction twin pregnancies. Large cohort studies do not indicate a higher rate of fetal congenital malformations in assisted-reproduction twins. Overall, assisted-reproduction twins in healthy women assisted-reproduction twins is only increased in women with a pre-existing medical condition such as hypertensive disorders and diabetes and most of these risks can be avoided with single-embryo transfer. Following the birth of the first IVF baby, rumours started to spread in both the medical literature and the media about the long-term health effects for children born following assisted reproduction treatment. However, after more than 30 years, the most common complications associated with IVF treatment remain indirect and technical such as the failure of treatment and ovarian hyperstimulation. Iatrogenic twinning has become the main side-effect of assisted reproduction treatment and the increasing number of twin pregnancies, in particular in older women, has generated numerous debates on the need for additional healthcare provision. In this review, we have evaluated the evidence for additional care that assisted-conception twin pregnancies may require compared with spontaneous twin pregnancies. Twin pregnancies are

  4. Twin specific risk factors in primary school achievements.

    Science.gov (United States)

    de Zeeuw, Eveline L; van Beijsterveldt, Catherina E M; de Geus, Eco J C; Boomsma, Dorret I

    2012-02-01

    The main aim of this study was to examine twin specific risk factors that influence educational achievement in primary school. We included prenatal factors that are not unique to twins, except for zygosity, but show a higher prevalence in twins than in singletons. In addition, educational achievement was compared between twins and their nontwin siblings in a within-family design. Data were obtained from parents and teachers of approximately 10,000 twins and their nontwin siblings registered with the Netherlands Twin Register. Teachers rated the proficiency of the children on arithmetic, language, reading, and physical education, and reported a national educational achievement test score (CITO). Structural equation modeling showed that gestational age, birth weight, and sex were significant predictors of educational achievement, even after correction for socioeconomic status. Mode of delivery and zygosity did not have an effect, while parental age only influenced arithmetic. Mode of conception, incubator time, and birth complications negatively affected achievement in physical education. The comparison of educational achievement of twins and singletons showed significantly lower ratings on arithmetic, reading, and language in twins, compared to their older siblings, but not compared to their younger siblings. Low gestational age and low birth weight were the most important risk factors for lower educational achievement of twins in primary school. It seems that the differences observed between twins and their nontwin siblings in educational achievement can largely be explained by birth order within the family.

  5. Cervical column morphology and craniofacial profiles in monozygotic twins.

    Science.gov (United States)

    Sonnesen, Liselotte; Pallisgaard, Carsten; Kjaer, Inger

    2008-02-01

    Previous studies have described the relationships between cervical column morphology and craniofacial morphology. The aims of the present study were to describe cervical column morphology in 38 pairs of adult monozygotic (MZ) twins, and compare craniofacial morphology in twins with fusions with craniofacial morphology in twins without fusion. Visual assessment of cervical column morphology and cephalometric measurements of craniofacial morphology were performed on profile radiographs. In the cervical column, fusion between corpora of the second and third vertebrae was registered as fusion. In the twin group, 8 twin pairs had fusion of the cervical column in both individuals within the pair (sub-group A), 25 pairs had no fusions (subgroup B), and in 5 pairs, cervical column morphology was different within the pair (subgroup C), as one twin had fusion and the other did not. Comparison of craniofacial profiles showed a tendency to increased jaw retrognathia, larger cranial base angle, and larger mandibular inclination in subgroup A than in subgroup B. The same tendency was observed within subgroup C between the individual twins with fusion compared with those without fusion. These results confirm that cervical fusions and craniofacial morphology may be interrelated in twins when analysed on profile radiographs. The study also documents that differences in cervical column morphology can occur in individuals within a pair of MZ twins. It illustrates that differences in craniofacial morphology between individuals within a pair of MZ twins can be associated with cervical fusion.

  6. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  7. Twin-twin transfusion syndrome: cerebral ischemia is not the only fetal MR imaging finding

    Energy Technology Data Exchange (ETDEWEB)

    Kline-Fath, Beth M. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Cincinnati Children' s Hospital, Department of Radiology, Cincinnati, OH (United States); Calvo-Garcia, Maria A.; O' Hara, Sara M.; Racadio, Judy M. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Crombleholme, Timothy M. [University of Cincinnati Medical Center, Department of Surgery, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States)

    2007-01-15

    Twin-twin transfusion syndrome (TTTS) is a complication of monochorionic/diamniotic twin pregnancies. An imbalance of blood flow occurs through placental anastomoses, causing potentially significant morbidity and mortality in both twins. Although the sonographic findings of TTTS are well documented, we believe that MR imaging is a valuable adjunct. We describe the fetal MR imaging findings associated with TTTS. From 2003 to 2005, 37 consecutive MR imaging studies were performed on multiple-gestation pregnancies. Of the 37, 25 were consistent with TTTS, correlated and confirmed by sonographic criteria. MR fetal abnormalities were documented. Cerebral ischemia, which could not be demonstrated by sonography, was delineated well by MR imaging. New findings noted on fetal MR imaging were enlargement of cerebral venous sinuses in both twins, dilatation of the renal collecting system in the recipient, lung lesions in the recipient and cerebral malformations in the donor. MR imaging is an important adjunct in TTTS imaging. Its benefit over sonography is its clear definition of cerebral pathology, which is important for intervention and counseling. The new findings, particularly in the urinary tract and cerebral venous sinuses, also help support the diagnosis of TTTS and might reveal additional consequences of the altered hemodynamics that occur in TTTS. (orig.)

  8. Twin-twin transfusion syndrome: cerebral ischemia is not the only fetal MR imaging finding

    International Nuclear Information System (INIS)

    Kline-Fath, Beth M.; Calvo-Garcia, Maria A.; O'Hara, Sara M.; Racadio, Judy M.; Crombleholme, Timothy M.

    2007-01-01

    Twin-twin transfusion syndrome (TTTS) is a complication of monochorionic/diamniotic twin pregnancies. An imbalance of blood flow occurs through placental anastomoses, causing potentially significant morbidity and mortality in both twins. Although the sonographic findings of TTTS are well documented, we believe that MR imaging is a valuable adjunct. We describe the fetal MR imaging findings associated with TTTS. From 2003 to 2005, 37 consecutive MR imaging studies were performed on multiple-gestation pregnancies. Of the 37, 25 were consistent with TTTS, correlated and confirmed by sonographic criteria. MR fetal abnormalities were documented. Cerebral ischemia, which could not be demonstrated by sonography, was delineated well by MR imaging. New findings noted on fetal MR imaging were enlargement of cerebral venous sinuses in both twins, dilatation of the renal collecting system in the recipient, lung lesions in the recipient and cerebral malformations in the donor. MR imaging is an important adjunct in TTTS imaging. Its benefit over sonography is its clear definition of cerebral pathology, which is important for intervention and counseling. The new findings, particularly in the urinary tract and cerebral venous sinuses, also help support the diagnosis of TTTS and might reveal additional consequences of the altered hemodynamics that occur in TTTS. (orig.)

  9. Reduced solar activity favors twin maternities.

    Science.gov (United States)

    Melnikov, Vladimir N

    2012-02-01

    Mechanisms underlying effects of physical factors on twin births are unclear. The present work studied an association between monthly and yearly multiple birth rates (MBRs) in the Novosibirsk region, south-west Siberia, in relation to solar activity (sunspot numbers) and geomagnetic activity (Ap index) from 1957 to 2008. The difference was verified by comparing the yearly MBR observed in 3-year peaks (M = 7.36, SD = 0.33 per 1,000 births) and 3-year troughs (M = 8.10, SD = 0.31 per 1,000 births, p twin maternities. The results show that elevated solar activity within the 11-year cycle coinciding with the time of conception inhibits multiple births in a manner depending on geomagnetic activity. It is hypothesized that the likely mechanism underlying the association is early fetal loss induced by solar radiation/flux and its terrestrial mediators.

  10. Exoplanets: the quest for Earth twins.

    Science.gov (United States)

    Mayor, Michel; Udry, Stephane; Pepe, Francesco; Lovis, Christophe

    2011-02-13

    Today, more than 400 extra-solar planets have been discovered. They provide strong constraints on the structure and formation mechanisms of planetary systems. Despite this huge amount of data, we still have little information concerning the constraints for extra-terrestrial life, i.e. the frequency of Earth twins in the habitable zone and the distribution of their orbital eccentricities. On the other hand, these latter questions strongly excite general interest and trigger future searches for life in the Universe. The status of the extra-solar planets field--in particular with respect to very-low-mass planets--will be discussed and an outlook on the search for Earth twins will be given in this paper.

  11. Twin screw granulation - review of current progress.

    Science.gov (United States)

    Thompson, M R

    2015-01-01

    Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.

  12. Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion

    NARCIS (Netherlands)

    van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Pasman, Suzanne A.; Vandenbussche, Frank P. H. A.

    2008-01-01

    Twin-twin transfusion syndrome (TTTS) is a severe complication of monozygotic (identical) twin fetuses sharing one single (monochorionic) placenta. TTTS is caused by a net inter-twin transfusion of blood through placental anastomoses, from one twin (the donor) to the other (the recipient), which

  13. Emergency separation of a xipho-omphalopagus twin in a developing country

    Directory of Open Access Journals (Sweden)

    Shukla R

    2010-01-01

    Full Text Available Female conjoined twins (thoraco-omphalopagus were delivered by emergency caesarean section in a private nursing home. On examination, one of the twins was dead and was threatening the survival of the surviving twin (twin A. An emergency separation was performed to salvage the surviving twin.

  14. Nutritional rickets in twins: a case report

    Directory of Open Access Journals (Sweden)

    D. Frasca

    2013-06-01

    Full Text Available Vitamin D deficiency rickets in infants attributable to inadeguate vitamin D intake and decreased exposure to sunligh continue to be reported in the United States and other Western Countries. The American Academy of Pediatrics raccomend that all infants, children and adolescent have a minumin intake of 400 UI of vitamin D per day. We describe a case of deficiency-related rickets in two moroccan twins aged 10 months.

  15. CONJOINED TWIN CALF IN A BUFFALO

    Directory of Open Access Journals (Sweden)

    Maqbool Ahmad, A. Khan1 and H.A. Samad

    2001-07-01

    Full Text Available The present case was a conjoined female twin calf joined at thorax having symmetrical two heads, two necks, four forelimbs, two hind limbs, single belly, distally separated two tails and single vulva (Dicephalus dipus tetrabrachius. When skin was incised and thoracic and abdominal cavities were opened, partial bifurcation of thoracic to lumbar vertebrae was observed. There were incompletely doubled lungs and hearts. The two esophagi joined .the common gastrointestinal tract. The urogenital system was single.

  16. Emergence and loss of spliceosomal twin introns

    OpenAIRE

    Flipphi, Michel; Ág, Norbert; Karaffa, Levente; Kavalecz, Napsugár; Cerqueira, Gustavo; Scazzocchio, Claudio; Fekete, Erzsébet

    2017-01-01

    Background In the primary transcript of nuclear genes, coding sequences—exons—usually alternate with non-coding sequences—introns. In the evolution of spliceosomal intron–exon structure, extant intron positions can be abandoned and new intron positions can be occupied. Spliceosomal twin introns (“stwintrons”) are unconventional intervening sequences where a standard “internal” intron interrupts a canonical splicing motif of a second, “external” intron. The availability of genome sequences of ...

  17. Comparison of perinatal outcomes of vanishing twin and twin pregnancies conceived following assisted reproductive technology: A retrospective analysis

    Directory of Open Access Journals (Sweden)

    Sujata Pradhan

    2016-12-01

    Full Text Available Objective: The purpose of this study was to compare the perinatal outcomes of vanishing twin (VT pregnancies with twin pregnancies following assisted reproductive technology treatment (ART. Design: Retrospective analysis. Setting: Infertility unit of a university level hospital. Materials and methods: We included all the women with dichorionic diamniotic twin pregnancies conceived following ART from Jan 2010 to Dec 2014 in our unit. We matched the VT group and twin group for maternal age and body mass index. Results: A total of 63 vanishing twin and 135 twin pregnancies were followed up. The vanishing twin rate was 31.8%. The live birth rate at term was significantly higher in VT group compared to twin group (69.8% vs. 16.3%, P 2500 g in VT group than in twin group (77.8% vs. 25.4%, P < 0.001. The miscarriage, Cesarean and congenital anomaly rates were similar in both the groups. Conclusion: Our study finding suggests better perinatal outcomes for ART pregnancies undergoing spontaneous reduction in first trimester compared to those pregnancies which continue as twins.

  18. Anorexia and Bulimia Nervosa in Same-Sex and Opposite-Sex Twins : Lack of Association With Twin Type in a Nationwide Study of Finnish Twins

    NARCIS (Netherlands)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W.; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-01-01

    Objective: The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Method: Finnish twins (N=2,426 women,

  19. Treatment responses to tooth whitening in twins.

    Science.gov (United States)

    Corby, Patricia M A; Biesbrock, Aaron; Gerlach, Robert; Corby, Andrea L; Moreira, Alexandre; Schork, Nicholas J; Bretz, Walter A

    2014-02-01

    The aim of this study was to determine heritability estimates of treatment responses to a 10% hydrogen peroxide strip-based whitening system in twins. Eighty-five twin pairs were randomly assigned to 10% hydrogen peroxide whitening strips or placebo strips without peroxide. Both twins (monozygotic or dizygotic) received the same treatment. Maxillary teeth were treated for 30 minutes twice daily for 7 days. Efficacy was measured objectively as L* (light-dark), a* (red-green), and b* (yellow-blue) color change from digital images at baseline (∆) and day 8. Heritability estimates for tooth whitening treatment responses for changes from day 8 to baseline were obtained using variance-component methodologies. Whitening treatment responses were highly heritable (h(2) = 71.0) for ∆b* and ∆a*(p < .0001), but not for ∆L* (h(2) = 27.0), which was essentially modulated by environmental factors. This study has demonstrated that both genetic and environmental factors significantly contributed to seven-day whitening treatment responses achieved with 10% hydrogen peroxide strips.

  20. Effect of twinning plane on superconductor magnetic properties

    International Nuclear Information System (INIS)

    Buzdin, A.I.; Kuptsov, D.A.

    1989-01-01

    Effect of twinning planes on pinning of the Abrikosov vortices in superconductors of the second order with the Ginsburg-Landau parameter, κ >> 1, is considered. The modified Ginsburg-Landau functional, where the effect of superconducting properties improvement near the twinning plane is taken into account by adding the additional δ-function component, is used to descibe superconductivity of twinning plane. Force of interaction of a vortex filament and the twinning plane is calculated. It is shown that in case of the twinning plane opaque to electrons, additional attractive force, being analogous to that occurring in the problem on the surface Been-Livingston barrier, affects the vortex filament. The results can explain anisotropy of vortex pinning observed in the periodic twinning structure in high-temperature superconductors

  1. Quality of life in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Bech, Per; Kyvik, Kirsten Ohm

    2007-01-01

    BACKGROUND: The disability and hardship associated with affective disorder is shared by the family members of affective patients and might affect the family member's quality of life. METHOD: In a cross-sectional, high-risk, case-control study, monozygotic (MZ) and dizygotic (DZ) twins with (High......-Risk twins) and without (the control group/Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. The aim of the present study was to investigate the hypothesis that a genetic liability to affective disorder is associated with a lower perception of quality...... of life. RESULTS: Univariate analyses showed that quality of life in all domains was impaired for the 121 High-Risk twins compared to the 84 Low-Risk twins. In multiple regression analyses, the differences remained significant after adjustment for sex, age, marital status and years of education. Adjusted...

  2. Atopic diseases in twins born after assisted reproduction

    DEFF Research Database (Denmark)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten Ohm

    2012-01-01

    Jäderberg I, Thomsen SF, Kyvik KO, Skytthe A, Backer V. Atopic diseases in twins born after assisted reproduction. Paediatric and Perinatal Epidemiology 2012; 26: 140-145. We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted...... reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression...... and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0...

  3. Prospective risk of stillbirth and neonatal complications in twin pregnancies

    DEFF Research Database (Denmark)

    Cheong-See, Fiona; Schuit, Ewoud; Arroyo-Manzano, David

    2016-01-01

    OBJECTIVE: To determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, and Cochrane databases (until December 2015). REVIEW METHODS......: Databases were searched without language restrictions for studies of women with uncomplicated twin pregnancies that reported rates of stillbirth and neonatal outcomes at various gestational ages. Pregnancies with unclear chorionicity, monoamnionicity, and twin to twin transfusion syndrome were excluded...... differences in risk were estimated for stillbirths and neonatal deaths in monochorionic and dichorionic twin pregnancies after 34 weeks' gestation. RESULTS: 32 studies (29 685 dichorionic, 5486 monochorionic pregnancies) were included. In dichorionic twin pregnancies beyond 34 weeks (15 studies, 17 830...

  4. Comparisons of dermatoglyphic patterns in monochorionic and dichorionic monozygotic twins.

    Science.gov (United States)

    Reed, T; Uchida, I A; Norton, J A; Christian, J C

    1978-01-01

    The data presented here indicate that different influences affect dermatoglyphic pattern development in MC-MZ and DC-MZ twins. Only five of 84 variables had significant mean differences but their clustering suggested a real difference in mean placement of the atd angle. Nineteen of 84 variables had significantly different within-pair mean squares for the two twin types. Larger numbers of twins will be required to obtain accurate estimates of the magnitude of the dermatoglyphic differences between MC-MZ and DC-MZ twins. Studies of dermatoglyphics in MC-MZ and DC-MZ twins are important to the understanding of factors which influence early embryonic development and when better documented may provide a mechanism for retrospectively diagnosing placental type of MZ twins. PMID:568879

  5. Coffee and smoking as risk factors of twin pregnancies

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Bech, Bodil Hammer; Christensen, Kaare

    2007-01-01

    Twinning rates have changed substantially over time for reasons that are only partly known. In this study we studied smoking, coffee and alcohol intake, and their possible interaction with obesity as potential determinants of twinning rates using data from the Danish National Birth Cohort between...... their prepregnancy weight and height, coffee and alcohol intake, smoking habits, and potential confounding factors at early stages of pregnancy. We identified smoking (> 10 cigarettes/day) as a possible determinant of twinning, particularly for dizygotic twinning rates (same sex) and furthermore corroborated...... that obesity and the mother's age are strong correlates of twinning. Others have found coffee intake to increase twinning rates but that is not seen in these data....

  6. 3D Evaluation of Palatal Rugae in Identical Twins

    OpenAIRE

    Taneva, Emiliya; Evans, Carla; Viana, Grace

    2017-01-01

    The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero? intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagno...

  7. Mortality following unilateral twin interstitial ectopic pregnancy. A case report.

    Science.gov (United States)

    Jackson, G M; Rubin, S M; Sondheimer, S J

    1992-10-01

    Twin ectopic pregnancy is an uncommon event, usually occurring as simultaneous intrauterine and tubal gestations. Interstitial implantation of an ectopic pregnancy is also a rare event, associated with a high mortality rate. Twin interstitial pregnancy has been previously reported only three times in the English literature. We report a recent case of unilateral twin interstitial ectopic pregnancy that resulted in maternal death and review the literature with regard to both ectopic pregnancy and factors associated with mortality from interstitial implantation.

  8. Twin removal in digital holography using diffuse illumination

    OpenAIRE

    Monaghan, David S.; Kelly, Damien P.; Pandey, Nitesh; Hennelly, Bryan M.

    2009-01-01

    A method to numerically remove the twin image for inline digital holography, using multiple digital holograms, is discussed. Each individual hologram is recorded by using a statistically independent speckle field to illuminate the object. If the holograms are recorded in this manner and then numerically reconstructed, the twin image appears as a different speckle pattern in each of the reconstructions. By performing specklereduction techniques the presence of the twin image can be...

  9. Crystallography of decahedral and icosahedral particles. I - Geometry of twinning

    Science.gov (United States)

    Yang, C. Y.

    1979-01-01

    The crystal structure of the tetrahedral twins in multiply-twinned particles with decahedral and icosahedral point group symmetries has been examined and correlated with the face-centered cubic structure. Details on the crystal structure as well as the geometrical relationships among twins in each particle are presented. These crystallographic facts serve as a basis for the interpretation of small particle images obtained with advanced methods of transmission electron microscopy.

  10. Kidney growth in twin children born small for gestational age.

    Science.gov (United States)

    Giapros, Vasileios; Drougia, Aikaterini; Hotoura, Efthalia; Argyropoulou, Maria; Papadopoulou, Frederica; Andronikou, Styliani

    2010-11-01

    Low birth weight (LBW) is associated with adult-onset diseases, including hypertension and renal disease; altered renal development after intrauterine growth restriction (IUGR) may underlie related prenatal programming. No data are available on longitudinal renal growth in twin infants born small for gestational age (SGA). The aim of this prospective longitudinal study was to estimate the renal size during the first 2 years of life in SGA twin infants. The study included 613 children, of which 145 were SGA twins, 141 twins appropriate for gestational age (AGA), 148 matched AGA singletons and 179 matched SGA singletons, classified according to GA into two groups (28-36 and >36 weeks). The SGA children were also classified according to the degree of IUGR: birth weight (BW) kidney length (KL) measurement was performed at the ages of 36 and 40 weeks corrected age (CA) and 3, 6, 12 and 24 months of age, and KL was related to other anthropometric indices. Twin data were examined both as individuals and as members of twin pairs. A total of 2317 measurements were performed. KL was lower at 40 weeks CA in all the SGA twin subgroups. In the SGA twins with GA >36 weeks, KL increased thereafter and became similar to AGA twins and single AGA control subjects. Among pre-term infants of GA <36 weeks, only those with BW 3rd-10th percentile experienced catch-up in KL, while in those with BW <3rd percentile, KL remained lower than in AGA infants throughout the study period, both in absolute terms and relative to other anthropometric indices. No differences in KL were found between twin SGA and singleton SGA or between twin AGA and singleton AGA infants. Intrapair BW differences were correlated with the intrapair differences in KL. Twin SGA infants born prematurely with BW <3rd percentile are unable to achieve catch-up in KL in the first 24 months of life, and long-term follow-up is recommended.

  11. Danish cohort of monozygotic inflammatory bowel disease twins

    DEFF Research Database (Denmark)

    Trier Møller, Frederik; Almind Knudsen, Lina; Harbord, Marcus

    2016-01-01

    from collection of samples to storage in the -80 °C mobile freezer was less than one hour. The diagnoses where validated using the Copenhagen diagnostic criteria. RESULTS: We identified 159 MZ IBD twin pairs, in a total of 62 (39%) pairs both twins agreed to participate. Of the supposed 62 IBD pairs...... comprised 31 UC, 5 IBDU (IBD unclassified), and 8 CD discordant pairs. In the co-twins not affected by IBD, calprotectin was above 100 μg/g in 2 participants, and above 50 μg/g in a further 5 participants. CONCLUSION: The presented IBD twin cohorts are an excellent resource for bioinformatics studies...

  12. Severe deformation twinning in pure copper by cryogenic wire drawing

    International Nuclear Information System (INIS)

    Kauffmann, A.; Freudenberger, J.; Geissler, D.; Yin, S.; Schillinger, W.; Sarma, V. Subramanya; Bahmanpour, H.; Scattergood, R.; Khoshkhoo, M.S.; Wendrock, H.; Koch, C.C.; Eckert, J.; Schultz, L.

    2011-01-01

    The effect of low-temperature on the active deformation mechanism is studied in pure copper. For this purpose, cryogenic wire drawing at liquid nitrogen temperature (77 K) was performed using molybdenum disulfide lubrication. Microstructural investigation and texture analysis revealed severe twin formation in the cryogenically drawn copper, with a broad twin size distribution. The spacing of the observed deformation twins ranges from below 100 nm, as reported in previous investigations, up to several micrometers. The extent of twin formation, which is significantly higher when compared to other cryo-deformation techniques, is discussed with respect to the state of stress and the texture evolution during wire drawing.

  13. Pregnancy outcome of monochorionic twins: does amnionicity matter?

    Science.gov (United States)

    Dias, Thiran; Contro, Elena; Thilaganathan, Basky; Khan, Hina; Zanardini, Cristina; Mahsud-Dornan, Samina; Bhide, Amar

    2011-12-01

    To compare the fetal loss rate of monochorionic (MC) twin pregnancies according to their amnionicity. A retrospective review of all MC pregnancy outcomes in a tertiary centre. Pregnancy outcomes were compared for monochorionic monoamniotic (MCMA) versus monochorionic diamniotic (MCDA) pregnancies. 29 MCMA and 117 MCDA twin pregnancies were identified. The overall fetal loss rate was significantly higher in MCMA (23/52, 44.2%) compared to MCDA pregnancies (28/233, 12%, Chi squared = 30.03, p fetal survival rate in MCDA twins were significantly higher than in MCMA twins (Log-rank Chi-squared = 27.9, p fetal losses in some MCMA twins. After exclusion of identifiable causes, the difference in fetal survival was not significant in the two groups (Log-rank chi-squared = 0.373, p = .54). The loss rate for MCMA twins is high and occurs mainly due to discordant congenital abnormality, conjoint twins or twin reversed arterial perfusion (TRAP) sequence. Although the fetal loss rate in MCDA is lower than in MCMA pregnancies, the majority of fetal loss in MCDA pregnancies cannot be predicted at the first scan at presentation. The data of this study questions the widespread policy of a difference in the scheduling of elective delivery for MCMA and MCDA twins.

  14. Genetics of dietary habits and obesity - a twin study

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise

    2010-01-01

    equation modelling of twin data from the Danish Twin Registry with special focus on the GEMINAKAR twin study that was performed in 1997-2000. In this study, anthropometric traits of the twin pairs were measured and habitual dietary intake was assessed through a food frequency questionnaire (FFQ). When...... residual genetic influence existed. Based on information about habitual diet from the FFQ the genetic influence on total energy intake, macronutrient intake, as well as intake of energy from 20 food groups, was estimated. The proportion of variation in dietary intake explained by variation in genes...

  15. Deformation of lamellar TiAl alloys by longitudinal twinning

    OpenAIRE

    Edwards, Thomas Edward James; Di Gioacchino, Fabio; Muñoz-Moreno, Rocío; Clegg, William John

    2016-01-01

    The occurrence of longitudinal twinning in the engineering alloy Ti-45Al-2Nb-2Mn (at%)-0.8vol% TiB2 has been studied by measuring the changes in crystallographic orientation within individual lamellae during microcompression. Twinning in this alloy appeared to be a nucleation-limited process with the twins growing from lamellar boundaries at resolved shear stresses as low as 100 MPa, consistent with observations elsewhere. However, instead of forming twins ~10-200 nm in thickness, as in polys...

  16. Atypical Ischiopagus Conjoined Twins: Discription of a Case

    Directory of Open Access Journals (Sweden)

    Alanur Güven

    2006-04-01

    Full Text Available Conjoined twinning is extremely rare congenital malformation occurring in a very low frequency. A 22-year-old woman presented with 33 weeks gestation to an obstetric clinic in activ e labor. The patient delivered conjoined male twins vaginally. External examination of the inf ants showed atypical ischiopagus twins. We emphasize that the precise knowledge of anatomic properties of both twins antenatally will help the obstetrician to decide the route of deliv ery and the pediatric surgeon to decide the surgical approach.

  17. Twinning interactions induced amorphisation in ultrafine silicon grains

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y. [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, L.C., E-mail: liangchi.zhang@unsw.edu.au [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, Y. [School of Mechatronics Engineering, Harbin Institute of Technology (China)

    2016-03-21

    Detailed transmission electron microscopy analysis on a severely deformed Al-Si composite material has revealed that partial dislocation slips and deformation twinning are the major plastic deformation carriers in ultrafine silicon grains. This resembles the deformation twinning activities and mechanisms observed in nano-crystalline face-centred-cubic metallic materials. While deformation twinning and amorphisation in Si were thought unlikely to co-exist, it is observed for the first time that excessive twinning and partial dislocation interactions can lead to localised solid state amorphisation inside ultrafine silicon grains.

  18. 3D Evaluation of Palatal Rugae in Identical Twins

    Directory of Open Access Journals (Sweden)

    Emiliya Taneva

    2017-01-01

    Full Text Available The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

  19. [Twin pregnancy as the risk factor for neonatal intraventricular hemorrhage].

    Science.gov (United States)

    Wieczorek, Aleksandra I; Krasomski, Grzegorz

    2015-02-01

    The aim of this study was to find the perinatal risk factors of intravenricular hemorrhage in twin neonates. A retrospective analysis of 203 twin pregnancies and deliveries between 2003 and 2009 was performed. Then data according birth state and neonatal complications in 406 twins were analyzed. Twin outcome was compared with the outcome of 105 singletons born at the same time and at the same gestational age as twins. Intraventricular hemorrhage was diagnosed in 116/406 (29%) of twins. IVH was found two times more often in the analyzed group than in singletons born at the same gestational age (29% vs. 18%, p = 0,03). In 96% I and II grade hemorrhage was diagnosed and in 4% III and IV grade hemorrhage in the Papille scale was found. 1) Intraventricular hemorrhage is found more often in twins than in singleton neonates born at the same gestational age. 2) IVH in twins correlate with preterm birth and low birth weight. IVH occur more often in twins with birth weight discordance and with too small maternal weight gain.

  20. 3D Evaluation of Palatal Rugae in Identical Twins

    Science.gov (United States)

    2017-01-01

    The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases. PMID:28611927

  1. 3D Evaluation of Palatal Rugae in Identical Twins.

    Science.gov (United States)

    Taneva, Emiliya; Evans, Carla; Viana, Grace

    2017-01-01

    The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

  2. Deformation twinning in irradiated ferritic/martensitic steels

    Science.gov (United States)

    Wang, K.; Dai, Y.; Spätig, P.

    2018-04-01

    Two different ferritic/martensitic steels were tensile tested to gain insight into the mechanisms of embrittlement induced by the combined effects of displacement damage and helium after proton/neutron irradiation in SINQ, the Swiss spallation neutron source. The irradiation conditions were in the range: 15.8-19.8 dpa (displacement per atom) with 1370-1750 appm He at 245-300 °C. All the samples fractured in brittle mode with intergranular or cleavage fracture surfaces when tested at room temperature (RT) or 300 °C. After tensile test, transmission electron microscopy (TEM) was employed to investigate the deformation microstructures. TEM-lamella samples were extracted directly below the intergranular fracture surfaces or cleavage surfaces by using the focused ion beam technique. Deformation twinning was observed in irradiated specimens at high irradiation dose. Only twins with {112} plane were observed in all of the samples. The average thickness of twins is about 40 nm. Twins initiated at the fracture surface, became gradually thinner with distance away from the fracture surface and finally stopped in the matrix. Novel features such as twin-precipitate interactions, twin-grain boundary and/or twin-lath boundary interactions were observed. Twinning bands were seen to be arrested by grain boundaries or large precipitates, but could penetrate martensitic lath boundaries. Unlike the case of defect free channels, small defect-clusters, dislocation loops and dense small helium bubbles were observed inside twins.

  3. Two sets of twins with selective mutism: neuropsychological findings.

    Science.gov (United States)

    Gray, Robert M; Jordan, Catherine M; Ziegler, Richard S; Livingston, Ronald B

    2002-03-01

    Neuropsychological data are reviewed from two sets of dizygotic twins presenting with selective mutism characterized by situation specific anxiety, extreme passive behavior, lack of responsivity, lack of peer interaction, and a chronic course of selective mutism. Both sets of twins had a history of prematurity and delayed speech development. One set of twins presented with normal intelligence and normal receptive language skills but with expressive language and oral motor sequencing difficulties. The second set of twins presented with Verbal IQ deficits and significant receptive and expressive language deficits. A summary of current conceptualizations regarding etiology and treatment of selective mutism is provided.

  4. Quality of life in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Bech, Per; Kyvik, Kirsten Ohm

    2006-01-01

    BACKGROUND: The disability and hardship associated with affective disorder is shared by the family members of affective patients and might affect the family member's quality of life. METHOD: In a cross-sectional, high-risk, case-control study, monozygotic (MZ) and dizygotic (DZ) twins with (High......-Risk twins) and without (the control group/Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. The aim of the present study was to investigate the hypothesis that a genetic liability to affective disorder is associated with a lower perception of quality...

  5. [The reproductive function in experimentally-produced monozygotic twin bulls].

    Science.gov (United States)

    Braun, J; Schams, D; Brem, G

    1990-06-01

    Reproductive functions were evaluated in 12 experimentally derived monozygotic cattle twins (6 pairs). In 4 twin pairs GnRH (20 micrograms Receptal i.m.) was administered in monthly intervals from 6 through 12 months of age. LH-secretion was determined by radioimmunoassay up to 6 hours after the GnRH-challenge in hourly collected peripheral blood samples. In 5 twin pairs (age 14 to 20 months) semen was collected 5 times and processed for cryoconservation. In fresh and in frozen-thawed semen samples sperm motility was determined by means of a computerized system. Twins showed a remarkable uniform response to the GnRH-challenge. One set of twins (HF-breed) had a significantly reduced response compared to the other pairs (DFV-breed). Both individuals of this particular pair had a low percentage of progressively motile spermatozoa. In pairs with physiological sperm motility, variance of this parameter within pairs and between pairs was not different. In contrast, twin uniformity concerning the average velocity of motile spermatozoa was high; differences between set of twins explained most of the total variance. According to this study, reproductive parameters in monozygotic cattle twins are strongly influenced by twin uniformity.

  6. The Concordance and Heritability of Type 2 Diabetes in 34,166 Twin Pairs From International Twin Registers

    DEFF Research Database (Denmark)

    Willemsen, G.; Ward, K. J.; Bell, C. G.

    2015-01-01

    Twin pairs discordant for disease may help elucidate the epigenetic mechanisms and causal environmental factors in disease development and progression. To obtain the numbers of pairs, especially monozygotic (MZ) twin pairs, necessary for in-depth studies while also allowing for replication, twin...... studies worldwide need to pool their resources. The Discordant Twin (DISCOTWIN) consortium was established for this goal. Here, we describe the DISCOTWIN Consortium and present an analysis of type 2 diabetes (T2D) data in nearly 35,000 twin pairs. Seven twin cohorts from Europe (Denmark, Finland, Norway...... and medication use, fasting glucose and insulin measures, or medical records. The prevalence of T2D ranged from 2.6% to 12.3% across the cohorts depending on age, body mass index (BMI), and national diabetes prevalence. T2D discordance rate was lower for MZ (5.1%, range 2.9-11.2%) than for same-sex dizygotic (DZ...

  7. Chromosomal Aberrations in Monozygotic and Dizygotic Twins Versus Singletons in Denmark During 1968-2009

    DEFF Research Database (Denmark)

    Kristensen, Lone Krøldrup; Larsen, Lisbeth A; Fagerberg, Christina

    2017-01-01

    BACKGROUND: Hall (Embryologic development and monozygotic twinning. Acta Geneticae Medicae et Gemellologiae, Vol. 45, 1996, pp. 53-57) hypothesized that chromosomal aberrations can lead to monozygotic (MZ) twinning. However, twinning and chromosomal aberrations increase prenatal mortality and could...

  8. Twin reversed arterial perfusion sequence is more common than generally accepted

    NARCIS (Netherlands)

    Gemert, M.J. van; Wijngaard, J.P. van den; Vandenbussche, F.P.H.A.

    2015-01-01

    BACKGROUND: Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack

  9. Twin reversed arterial perfusion sequence is more common than generally accepted

    NARCIS (Netherlands)

    van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Vandenbussche, Frank P. H. A.

    2015-01-01

    Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack a functional

  10. [Acardiac headless twin: a case report and review of the literature].

    Science.gov (United States)

    Boufettal, H; Noun, M; Hermas, S; Samouh, N

    2010-03-01

    Monochorial twin pregnancies are characterised by the presence of vascular connections between the twins. These connections can be the cause of pathologies such as the twin-twin transfusion syndrome or the TRAP syndrome, which is defined as the association of a headless, acardiac twin with a healthy twin. The case of an acardiac, headless twin diagnosed during pregnancy at 24 weeks of amenorrhea is described. An acardiac headless twin is a rare phenomenon. Yet early diagnosis is crucial during pregnancy to provide adequate monitoring. It is associated with a high death rate in the healthy twin caused by anaemia and heart failure. Therapeutic resources involve interruption of vascular anostomoses between the twins in order to perform a selective feticide. Treatment of acardiac headless twin pregnancy ranges from obstetric abstentionism to interventionism, which depends on the prognosis for the healthy twin, dominated by the risk of preterm birth and heart failure. Copyright 2009. Published by Elsevier SAS.

  11. Effects of surface damage on twinning stress and the stability of twin microstructures of magnetic shape memory alloys

    International Nuclear Information System (INIS)

    Chmielus, Markus; Witherspoon, Cassie; Ullakko, Kari; Muellner, Peter; Schneider, Rainer

    2011-01-01

    Research highlights: → Electropolishing reduces residual stresses in surfaces of magnetic shape-memory alloys and reduces the twinning stress. → Mechanical polishing and grinding produces a layer of defects on surfaces and increases the twinning stress of magnetic shape-memory alloys. → Defects localized near the surface (surface damage) increase the twinning stress and smoothen the stress-strain curve. → Defects localized near the surface create a stable and dense twin microstructure with mobile twins which extend throughout the entire crystal. → A stable dense twin microstructure provides the basis for fatigue-resistant magnetic shape-memory alloys. - Abstract: Twinning is the primary deformation mechanism in magnetic shape memory alloys (MSMAs). Obstacles such as inclusions, precipitates and defects hinder or even prevent twin boundary motion in the bulk of Ni-Mn-Ga MSMA single crystals. Here, we study the effect of surface damage on the mechanical properties and twin structure of Ni-Mn-Ga single crystals. Any methods that produce defects may be considered for modifying the near-surface microstructure. In this study deformations were produced by grinding and mechanical polishing using abrasive particles. The amount of damage was characterized with X-ray diffraction: damage causes peak broadening. Deformation and damage localized near the surface increases the twinning stress. Surface damage stabilizes a densely twinned microstructure. The twins are thin but extend over the entire sample and allow a large strain to be accommodated at moderate stress. This effect is critical for preventing damage accumulation in high-cycle magnetomechanical actuation and for achieving high dynamic performance.

  12. A Case of Monozygotic Twins: The Value of Discordant Monozygotic Twins in Goldenhar Syndrome—OMIM%164210

    Directory of Open Access Journals (Sweden)

    K. N. Venkateshwara Prasad

    2013-01-01

    Full Text Available Goldenhar syndrome is a rare developmental disorder characterised by hemifacial microsomia, epibulbar tumours, ear malformation, and vertebral anomalies. As monozygotic (MZ twins are believed to be genetically identical, discordance for disease phenotype between MZ twins varies with craniofacial anomalies, cardiac, vertebral, and central nervous system defects sporadically. We report a case of monozygotic female twins discordant for Goldenhar syndrome with hemifacial microsomia and the dysplasia of auricular pinna.

  13. Dysmorphism in one of a set of male twins; Could they have been identical twins? A diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Aliyu Ibrahim

    2014-01-01

    Full Text Available Twinning occurs worldwide, but Nigerian women of the southwest extraction record one of the highest rates in the world. Among the notable risk factors for fraternal twinning is advanced maternal age, which is also an independent risk factor for Down syndrome. Even as morphological characteristics can easily be applied to distinguish identical from fraternal twins, in cases of an associated dysmorphism, in any member of the couplet, it becomes a difficult tool to use, as has been observed in the case of a set of twins who were of the same sex, blood group, hemoglobin genotype, and shared the same placenta.

  14. Risk factors for emergency cesarean delivery of the second twin after vaginal delivery of the first twin.

    Science.gov (United States)

    Suzuki, Shunji

    2009-06-01

    A case-control study of twins was performed to identify clinical predictions of emergency cesarean delivery in the second-born twin after vaginal delivery of the first twin. The obstetric records were reviewed of all twin vaginal deliveries at the Japanese Red Cross Katsushika Maternity Hospital from 2002 through 2007. There were 206 vaginal deliveries of first twins at >or=33 weeks of gestation. Of these deliveries, nine women (4.4%) underwent an emergency cesarean for the delivery of the second twin. The incidence of cesarean delivery for the second twin was significantly greater in cases with a history of infertility therapy (odds ratio: 5.0, 95% confidence intervals: 1.2-22), gestational age at >or=39 weeks (24, 4.7-120), nonvertex presentation (6.2, 1.5-26), operative delivery of the first twin (6.1, 1.5-24) and intertwin delivery time interval >30 min (7.2, 1.7-30). The most important risk factor of emergency cesarean delivery in the second twin was a gestational age of >or=39 weeks.

  15. Dauphiné twinning microstructure in naturally deformed quartzites

    Science.gov (United States)

    Rahl, J. M.; McGrew, A. J.; Fox, J. A.

    2017-12-01

    We describe a detailed investigation into the twinning microstructure of incipiently deformed naturally occurring quartzites. Dauphiné twins in quartz can be described by a 180° rotation around the quartz c-axis that transposes the positive and negative forms of quartz. Although such twins can form through several mechanisms, including during high-temperature grain growth or upon cooling through the alpha-beta quartz phase transition, twins may form at lower temperatures as a mechanical response to stress. The elastic properties of quartz are anisotropic, with the negative rhomb faces {z} being nearly twice as stiff as the more compliant positive rhombs {r}. Although twinning does not accommodate permanent strain, it may act to maximize elastic distortion by aligning the more compliant face at high angle to the greatest principal stress. This phenomenon has previously been proposed to represent a potential paleostress tool. We present high-resolution crystallographic maps of quartzites obtained by electron backscatter diffraction. For samples from several natural settings, we find that between 60-70% of grains contain twins. For each twinned grain we calculated the relative area of each domain to define the dominant (larger) and subordinate (smaller) twins. We compare the crystallographic preferred orientations (CPOs) for the untwinned grains with those of the dominant and subordinate twins. We find that the CPO of the dominant twins is a strikingly similar but more diffuse version of that for the untwinned grains, whereas the subordinate twins show a complementary but weaker pattern characterized by voids near {r} and concentrations near {z}. These observations suggest that the subordinate twins represent relict host grains in elastically stiffer orientations. We performed a three-dimensional strain analysis for a subset of samples. For these samples, the untwinned grains are those with the compliant {r} face perpendicular to the maximum shortening direction

  16. From monster to twin reversed arterial perfusion: a history of acardiac twins.

    Science.gov (United States)

    Obladen, Michael

    2010-05-01

    A human being born without heart and head, i.e., the acardius/acranius malformation, has been described since antiquity. Superstition and fear made it a mystical disorder, a sign of God's wrath. The inquisition ruled that acranic infants should not be baptized and located the soul in the brain. Acardia was not associated with twin gestation until the reports of Mery in 1720 and Winslow in 1740. In 1850, Meckel identified the pathogenetic mechanism as reversed perfusion due to large arterio-arterial and veno-venous anastomoses; he believed the heart would fail to develop or arrest during development, and the acardiac fetus would be maintained by arterial perfusion from the pump twin. In 1859, Claudius articulated that after normal initial development, the heart degenerates when reversed flow in the aorta leads to thrombosis. Today, it is assumed that both mechanisms may exist. With the advent of prenatal ultrasound diagnosis and radiofrequency ablation of the acardiac twin's circulation, it became possible to save the pump twin.

  17. Evaluation of long-term neurodevelopment in twin-twin transfusion syndrome after laser therapy.

    Science.gov (United States)

    Sananès, Nicolas; Gabriele, Victor; Weingertner, Anne Sophie; Ruano, Rodrigo; Sanz-Cortes, Magdalena; Gaudineau, Adrien; Langer, Bruno; Nisand, Israël; Akladios, Chérif Youssef; Favre, Romain

    2016-12-01

    The primary objective of our study was to evaluate the long-term neurodevelopment outcome after laser surgery for twin-twin transfusion syndrome (TTTS). The secondary objective was to identify perinatal prognostic factors associated with neurodevelopmental impairment. This was a single-center cohort prospective study carried out in pregnancies complicated by TTTS and treated by laser. Neurodevleopmental assesment included the administration of Ages and Stages Questionnaires® (ASQ), for the infants between 2 and 5 years of age. A total of 187 patients underwent a laser for TTTS between 2004 and 2013. Significant brain lesions were detected in eight (2.9%) cases by ultrasound and/or magnetic resonance imaging including intraventricular hemorrhage, periventricular leukomalacia, and porencephaly. Questionnaires were administered to 126 children (50.4%) at 24 months or older at the moment of testing. There were 13.5% of those infants who had an abnormal ASQ (established as one area or more scoring < 2 SD) at 3.6 years ±1.3 follow-up. There was a higher rate of abnormal ASQ among the infants with a birth weight below the fifth percentile (p = 0.036). Twin-twin transfusion syndrome is associated with a risk of abnormal neurological development, even in case of laser surgery. Further studies are necessary to identify the risk factors for neurological impairment. © 2016 John Wiley & Sons, Ltd. © 2016 John Wiley & Sons, Ltd.

  18. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  19. Optical Properties of Rotationally Twinned Nanowire Superlattices

    DEFF Research Database (Denmark)

    Bao, Jiming; Bell, David C.; Capasso, Federico

    2008-01-01

    blende InP nanowires. We have constructed the energy band diagram of the resulting multiquantum well heterostructure and have performed detailed quantum mechanical calculations of the electron and hole wave functions. The excitation power dependent blue-shift of the photoluminescence can be explained...... a heterostructure in a chemically homogeneous nanowire material and alter in a major way its optical properties opens new possibilities for band-structure engineering.......We have developed a technique so that both transmission electron microscopy and microphotoluminescence can be performed on the same semiconductor nanowire over a large range of optical power, thus allowing us to directly correlate structural and optical properties of rotationally twinned zinc...

  20. New View of Twin Peaks Region

    Science.gov (United States)

    1997-01-01

    This image taken on Sol 74 ( September 17) from the Sojourner rover's right front camera shows areas of the Pathfinder landing site never before seen. The shadow of the rover and its antenna is visible in the foreground. On the horizon at right are the Twin Peaks, about 1 kilometer away.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  1. [Gestational diabetes insipidus during a twin pregnancy].

    Science.gov (United States)

    De Mesmay, M; Rigouzzo, A; Bui, T; Louvet, N; Constant, I

    2013-02-01

    Gestational diabetes insipidus is an uncommon clinical disease whose prevalence is approximately two to three pregnancies per 100,000. It may be isolated or associated with preeclampsia. We report a case of gestational diabetes insipidus in a twin pregnancy, originally isolated during two months, and secondarily complicated by HELLP-syndrome. We recall the specific pathophysiology of polyuric-polydipsic syndrome during pregnancy and summarize its various causes. Finally, we discuss the indications, in case of isolated gestational diabetes insipidus, of treatment by dDAVP. Copyright © 2013. Published by Elsevier SAS.

  2. Determinants of monozygotic twinning in ART

    DEFF Research Database (Denmark)

    Hviid, Kathrine Vauvert R; Malchau, Sara Sofia; Pinborg, Anja

    2018-01-01

    BACKGROUND: The incidence of monozygotic twins (MZT) after ART appears to be higher than the incidence after spontaneous conceptions contradicting the aim of ART to avoid multiple pregnancies because of the associated risks. OBJECTIVE AND RATIONALE: The aim was to study the frequency of MZT after...... only on case studies. All of the articles were categorized according to the Oxford Centre for Evidence-based Medicine's 'Levels of Evidence', and quality and risk of bias assessment was performed with 'The Cochrane Collaboration's Risk of Bias Tools'. A meta-analysis was performed to study the impact...

  3. Generalized Lichen Nitidus in Identical Twins

    Directory of Open Access Journals (Sweden)

    Alexander K. C. Leung

    2012-01-01

    Full Text Available Lichen nitidus is an uncommon idiopathic chronic dermatosis characterized by minute, flesh-colored or hypopigmented, shiny papules commonly occurring on the abdomen, chest, genitalia, and extremities. The disorder is most often localized but, rarely, can become extensive or generalized. The occurrence of lichen nitidus during infancy is extremely rare. A perusal of the English literature revealed but two cases. We report two identical twins with lesions of generalized lichen nitidus noted at two months of age. The familial occurrence of lichen nitidus suggests that a genetic factor may be operative.

  4. Invasive treatment in complicated monochorionic twin pregnancies

    DEFF Research Database (Denmark)

    Sundberg, Karin; Søgaard, Kirsten; Jensen, Lisa Neerup

    2012-01-01

    Objective. Monochorionic twin pregnancies are associated with increased risk of severe complications. Umbilical cord occlusion (UCO) and fetoscopic selective laser coagulation (FSLC) are used as invasive treatment. The study aim was to document treatment indications and pregnancy outcome where UCO......). Umbilical cord occlusion was undertaken in 49 TTTS cases, in four cases with fetal abnormality and TTTS and in 12 cases because of fetal anomaly only. Main outcome measures. Overall survival per fetus, survival per pregnancy of at least one fetus and further survival according to the Quintero stages. Infant...

  5. Cardiac pathophysiology in twin-twin transfusion syndrome: new insights into its evolution.

    Science.gov (United States)

    Wohlmuth, C; Boudreaux, D; Moise, K J; Johnson, A; Papanna, R; Bebbington, M; Gardiner, H M

    2018-03-01

    In twin-twin transfusion syndrome (TTTS), unbalanced transfer of vasoactive mediators and fluid from the donor to the recipient cotwin alters their cardiovascular function. The aims of this study were to describe the impact of TTTS on fetal cardiac function in a large cohort of monochorionic-diamniotic (MCDA) pregnancies, and determine the early hemodynamic response to selective fetoscopic laser photocoagulation (SFLP). Echocardiography was performed in 145 MCDA pregnancies, including 26 uncomplicated MCDA, 61 TTTS Stages I+II and 58 TTTS Stages III+IV pregnancies, prior to SFLP for TTTS. Echocardiographic data after SFLP were available in a subset of 41/119 (34%) TTTS cases at a mean of 1.7 ± 1.9 days. Mitral (MAPSE) and tricuspid (TAPSE) annular systolic excursion, myocardial performance index (MPI), tissue Doppler velocities (E', A', S') and filling pressures (E/E') were measured and transformed into Z-scores. Ventricular pressure was estimated from peak atrioventricular regurgitation velocity. Left ventricular hemodynamics of the recipient twin were affected in early TTTS. In all stages of TTTS, left MPI and E/E' of the recipient twin were elevated in comparison to those of the donor (all P group difference in right ventricular E/E' was significant only in TTTS Stages III+IV recipients compared with TTTS Stages I+II (P = 0.007) and uncomplicated MCDA (P = 0.041). Recipient left and right MPI decreased while S', MAPSE and TAPSE increased after SFLP; in donors, left E/E' and cardiac output increased. Cardiac function of the recipient twin in TTTS is abnormal, even in the early stages of the disease. Left ventricular filling pressures are elevated and systolic function is decreased before abnormalities in the right heart become apparent. SFLP produces rapid hemodynamic improvement. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

  6. Twinning in copper deformed at high strain rates

    Indian Academy of Sciences (India)

    −1) were investigated using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Twinned crystals consist of two parts symmetrically related to one another either by rotation or reflection. Twins can originate during annealing or deformation. It is impor- tant to note that the crystal orientation ...

  7. Twin pregnancies: risks and complications: review article | Patel ...

    African Journals Online (AJOL)

    ... structural anomalies can be excluded and growth monitored, while Doppler velocimetry of the umbilical artery can detect placental insufficiency. Monochorionic pregnancies are at highest risk of adverse outcome due to specific complications, such as twin-to-twin transfusion syndrome. O & B Forum Vol.14(2) 2004: 13-19 ...

  8. Assessment of Deformation Twinning in Cold Rolled Austenitic ...

    African Journals Online (AJOL)

    Deformation twinning has traditionally been studied with Transmission Electron Microscopy (TEM). In this study, an assessment of deformation twinning in Austenitic Stainless Steel (ASS), type 304L, cold rolled to 20% reduction was investigated using Scanning Electron Microscopy (SEM) and Electron Back Scatter ...

  9. Diecephalic thoraco-omphalopagus conjoined twins: case report ...

    African Journals Online (AJOL)

    We present a case report of conjoined twins discovered at 17 weeks gestation on routine trans-abdominal ultrasound in a 27 year old woman. The twins were joined at the chest and upper abdomen. They shared a heart, liver, sternum and diaphragm. The patient opted for termination of the pregnancy which was performed ...

  10. Genetic and Epigenetic Differences in Monozygotic Twins with NF1

    Science.gov (United States)

    2011-10-01

    parents and co-twins Data analysis has been performed on the first 5 pairs of twins enrolled. CNV s were visually inspected, compared to known...D E Age (years) 18 10 9 6 5 Gender F F F F F CAL#s Cut. NF Lisch Plexiform# OPG T2 Hyperint Scoliosis Pectus MPNST MR LD Speech ADHD

  11. Twin Ritual (Kamta Bulikur): The Significance of Traditional Music in ...

    African Journals Online (AJOL)

    2016-12-16

    Dec 16, 2016 ... This paper examines Bura notions of twinship and the significance of traditional music in the kamta ... nificance of music in the rituals, the belief system of the people concerning twins is explored as well. .... medicine man, deaha, and a traditional musician play key roles at the naming ritual of twins. When a ...

  12. Gamma-rays from dark showers with twin Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Freytsis, Marat [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Knapen, Simon; Robinson, Dean J. [Department of Physics, University of California,Berkeley, CA 94720 (United States); Ernest Orlando Lawrence Berkeley National Laboratory,University of California, Berkeley, CA 94720 (United States); Tsai, Yuhsin [Maryland Center for Fundamental Physics, Department of Physics,University of Maryland, College Park, MD 20742 (United States)

    2016-05-03

    We consider a twin WIMP scenario whose twin sector contains a full dark copy of the SM hadrons, where the lightest twin particles are twin pions. By analogy to the standard WIMP paradigm, the dark matter (DM) freezes out through twin electroweak interactions, and annihilates into a dark shower of light twin hadrons. These are either stable or decay predominantly to standard model (SM) photons. We show that this ‘hadrosymmetric’ scenario can be consistent with all applicable astrophysical, cosmological and collider constraints. In order to decay the twin hadrons before the big-bang nucleosynthesis epoch, an additional portal between the SM and twin sector is required. In most cases we find this additional mediator is within reach of either the LHC or future intensity frontier experiments. Furthermore, we conduct simulations of the dark shower and consequent photon spectra. We find that fits of these spectra to the claimed galactic center gamma-ray excess seen by Fermi-LAT non-trivially coincide with regions of parameter space that both successfully generate the observed DM abundance and exhibit minimal fine-tuning.

  13. A twin-family study of general IQ

    NARCIS (Netherlands)

    Leeuwen, M; van den Berg, Stéphanie Martine; Boomsma, D.I.

    2008-01-01

    In this paper we assess the presence of assortative mating, gene¿environment interaction and the heritability of intelligence in childhood usinga twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortativemating in

  14. A twin-family study of general IQ.

    NARCIS (Netherlands)

    van Leeuwen, M.; van den Berg, S.M.; Boomsma, D.I.

    2008-01-01

    In this paper we assess the presence of assortative mating, gene-environment interaction and the heritability of intelligence in childhood using a twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortative mating

  15. Assessment of dental caries and oral hygiene status among twins

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2018-01-01

    Full Text Available The study of twins provides a unique opportunity to evaluate the genetic and nongenetic contributions to a variance of multitude of traits. Twin research has revealed the impact of a strong genetic component to the variance of many dental traits. The present study was conducted to assess the dental caries and oral hygiene status in monozygotic (MZ and dizygotic (DZ twins. A random sample of 129 MZ and DZ twin pairs aged 6-15 years were included in this study. The zygosity of twin pairs was initially recorded by facial appearance and later determined by dermatoglyphics. Dental caries and oral hygiene status were recorded in these twin pairs and the data were subjected to statistical analysis. No significant difference was observed in the mean decayed, extracted due to caries and filled teeth (deft in primary dentition and decayed, missing and filled (DMFT in permanent dentition scores and oral hygiene status in MZ and DZ twin pairs. The similarity observed in oral health status reflects the effects of a shared environment in MZ and DZ twin pairs.

  16. Pregnancy outcome and factors affecting vaginal delivery of twins at ...

    African Journals Online (AJOL)

    Objective: The study aims to determine the differences in maternal and perinatal outcomes between caesarean and vaginal deliveries and the factors affecting vaginal delivery in twin pregnancy. Materials and Methods: An observational study to audit twin pregnancies delivered at the University of Nigeria Teaching Hospital ...

  17. Case of twin pregnancy complicated by idiopathic thrombocytopenic ...

    African Journals Online (AJOL)

    Idiopathic thrombocytopenic purpura (ITP) is an acquired thrombocytopenia without other clear cause of thrombocytopenia. It is not common in a singleton pregnancy and less common in twin pregnancy. We report a 33‑year‑old ITP pluripara whose first pregnancy was uneventful. She carried twin pregnancy, complicated ...

  18. Dicephalus dipus tetrabrachius conjoined twins of Zaria: Case report ...

    African Journals Online (AJOL)

    Dicephalus dipus tetrabrachius conjoined twins of Zaria: Case report and literature review. ... More commonly known as Siamese twins, this phenomenon is shrouded in mystery and considered a curiosity by general public. Current technology is lending a helping hand in the early diagnosis of these conditions. Frequently ...

  19. A study of multibiometric traits of identical twins

    Science.gov (United States)

    Sun, Zhenan; Paulino, Alessandra A.; Feng, Jianjiang; Chai, Zhenhua; Tan, Tieniu; Jain, Anil K.

    2010-04-01

    The increase in twin births has created a requirement for biometric systems to accurately determine the identity of a person who has an identical twin. The discriminability of some of the identical twin biometric traits, such as fingerprints, iris, and palmprints, is supported by anatomy and the formation process of the biometric characteristic, which state they are different even in identical twins due to a number of random factors during the gestation period. For the first time, we collected multiple biometric traits (fingerprint, face, and iris) of 66 families of twins, and we performed unimodal and multimodal matching experiments to assess the ability of biometric systems in distinguishing identical twins. Our experiments show that unimodal finger biometric systems can distinguish two different persons who are not identical twins better than they can distinguish identical twins; this difference is much larger in the face biometric system and it is not significant in the iris biometric system. Multimodal biometric systems that combine different units of the same biometric modality (e.g. multiple fingerprints or left and right irises.) show the best performance among all the unimodal and multimodal biometric systems, achieving an almost perfect separation between genuine and impostor distributions.

  20. Genetic influences on dietary variety - Results from a twin study

    NARCIS (Netherlands)

    Scheibehenne, Benjamin; Todd, Peter M.; van den Berg, Stéphanie Martine; Hatemi, Peter K.; Eaves, Lindon J.; Vogler, Christian

    2014-01-01

    The heritability of variety seeking in the food domain was estimated from a large sample (N = 5,543) of middle age to elderly monozygotic and dizygotic twins from the “Virginia 30,000” twin study. Different dietary variety scores were calculated based on a semi-quantitative food choice questionnaire

  1. Four decades of conjoined twins at Red Cross Children's Hospital ...

    African Journals Online (AJOL)

    Conjoined twins represent a rare but fascinating congenital condition, the aetiology of which remains obscure. Over the past four decades, the paediatric surgeons at Red Cross Children's Hospital have been involved in the management of 4;6 pairs of conjoined twins, of which 33 have been symmetrical and 12 ...

  2. Anaesthesia for conjoined twins | Fenton | Malawi Medical Journal

    African Journals Online (AJOL)

    The oxyhaemoglobin saturation of a set of conjoined twins was measured before and during supplementary oxygen administration and inhalation anaesthesia to assess the extent to which oxygen given to one twin could maintain oxygenation in the other before separation. The process of anaesthesia revealed that ...

  3. Management of Conjoined Twins During Neonatal Period | Ali ...

    African Journals Online (AJOL)

    Background/Purpose: Conjoined twins are rare and complex anomalies of the newborn. It is reported in 1/50.000 to 1/100.000 live births. The aim of the study was to summarize the experiences gained during separation of 5 sets of conjoined twins with presentation of literature review. Materials & Methods: During the period ...

  4. Congenital malaria in newborn twins | Opare | Ghana Medical Journal

    African Journals Online (AJOL)

    According to the mother, even though she did not sleep in insecticide treated bed net during her pregnancy, she took all the recommended drugs of sulfadoxine/ pyrimethamine- intermittent preventive treatment for malaria. She delivered twins on the same day. The mother and the twins developed fever on the same day.

  5. The occurrence and development of 'Siamese twins' and other ...

    African Journals Online (AJOL)

    1991-10-21

    Oct 21, 1991 ... In many instances the twins are co joined by other body parts such as the head or the tail, or one individual appears normal with a malformed sibling attached on its flank or ventrum. The above authors briefly comment on these abnormal occurrences. In this paper, the develop- ment of two pairs of twins in ...

  6. Case of twin pregnancy complicated by idiopathic thrombocytopenic ...

    African Journals Online (AJOL)

    2016-05-09

    May 9, 2016 ... Idiopathic thrombocytopenic purpura (ITP) is an acquired thrombocytopenia without other clear cause of thrombocytopenia. It is not common in a singleton pregnancy and less common in twin pregnancy. We report a 33‑year‑old ITP pluripara whose first pregnancy was uneventful. She carried twin ...

  7. Frequency of twinning in Kwara State, North-Central Nigeria

    African Journals Online (AJOL)

    O.A. Iyiola

    2012-10-05

    Oct 5, 2012 ... South Brazil implicating founder effect hypotheses as possible explanation for the prevalence [10]. Twins are classified into two types namely monozygotic. (MZ) and dizygotic ..... ethnicity and migration. Consistent with the general belief that maternal age influ- ences twinning, our data from UITH,EGH and ...

  8. Gender Differences in Mother-Neonate Twin Interaction.

    Science.gov (United States)

    Riese, Marilyn L.

    To investigate differences in mothers' interaction patterns with their neonate twins based on birth order, relative size at birth, or gender, 37 neonate twins and their mothers were observed during the first 10 minutes of a feeding in a hospital nursery. Time-sampling recordings were made of maternal behaviors related to proximal stimulation,…

  9. Genomewide association study to detect QTL for twinning rate in ...

    Indian Academy of Sciences (India)

    2014-07-14

    Jul 14, 2014 ... Twinning rate in sheep has great economic importance for farmers. A genomewide association study, using 42,416 sin- gle nucleotide polymorphisms (SNPs) was conducted to identify genomic regions affecting twinning rate in Baluchi sheep. Blood samples from a total of 96 sheep from two herds and data ...

  10. Determinants of Perinatal Mortality in Twins at Ibadan | Olayemi ...

    African Journals Online (AJOL)

    Context: Twinning being a very important high-risk condition in our environment requires detailed study. There are several studies reviewing factors in twin perinatal mortality in our environment but there is a need to ascertain the relative contributions of each of these factors. Objectives: To assess the relative contributions of ...

  11. Spontaneous Live Twin Tubal Ectopic Pregnancy: A Case Report

    Directory of Open Access Journals (Sweden)

    R Benn

    2016-02-01

    Full Text Available We report the case of a 29-year old G3P1+1 woman with a spontaneously conceived live twin tubal ectopic pregnancy. Her history was significant for infertility for 11 years after an induced abortion. Pelvic ultrasound scan showed live twin ectopic pregnancy and a partial salpingectomy was done.

  12. Cytokines and the Risk of Preterm Delivery in Twin Pregnancies

    DEFF Research Database (Denmark)

    Rode, Line; Klein, Katharina; Larsen, Helle

    2012-01-01

    To estimate the association between cytokine levels in twin pregnancies and risk of spontaneous preterm delivery, including the effect of progesterone treatment.......To estimate the association between cytokine levels in twin pregnancies and risk of spontaneous preterm delivery, including the effect of progesterone treatment....

  13. Perinatal Complications of Twin Deliveries at Jimma University ...

    African Journals Online (AJOL)

    Twin pregnancy carries higher foetal and neonatal complications. This situation is worse in Sub-Saharan Africa due to lack of well-equipped facilities. Studies on twin pregnancy and its perinatal complications are limited in Ethiopia. Thus, this study aimed to fill this gap. A hospital-based cohort study was conducted in Jimma ...

  14. Adolescent idiopathic scoliosis in twins: a population-based survey

    DEFF Research Database (Denmark)

    Andersen, Mikkel O; Thomsen, Karsten; Kyvik, Kirsten O

    2007-01-01

    STUDY DESIGN: A questionnaire-based identification of adolescent idiopathic scoliosis (AIS) patients in a twin cohort. OBJECTIVE: The purpose of this study was to establish a scoliosis twin cohort to provide data on the heritability of AIS. SUMMARY OF BACKGROUND DATA: The etiology of AIS is still...

  15. I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

    Science.gov (United States)

    Segal, Nancy L; Marcheco-Teruel, Beatriz

    2014-08-01

    I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr.

  16. Gas and Gas Pains

    Science.gov (United States)

    ... Gas and gas pains Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  17. Salivary cortisol in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Bennike, Bente; Kyvik, Kirsten Ohm

    2008-01-01

    Dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a biological endophenotype for affective disorders. In the present study the hypothesis that a high genetic liability to affective disorder is associated with higher cortisol levels was tested in a cross....... In conclusion, a high genetic liability to affective disorder was associated with a higher evening cortisol level, but not with awakening cortisol level. Future prospective family, high-risk and twin studies are needed to decide whether abnormalities in the HPA axis can be identified as an endophenotype......-sectional high-risk study. Healthy monozygotic (MZ) and dizygotic (DZ) twins with (High-Risk twins) and without (Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. Awakening and evening salivary cortisol levels were compared between the 190 High- and Low...

  18. Surgical management of pygopagus conjoined twins with spinal bifida.

    Science.gov (United States)

    Awasthi, Rahul; Iyengar, Raghvan; Rege, Shrikant; Jain, Nilesh

    2015-05-01

    Conjoined twins are a rare complication of 9 monozygotic twins and are associated with high perinatal mortality. Pygopagus are one of the rare types of conjoined twins with only a handful of cases reported in the literature. We present the case of one-and-half month-old male pygopagus conjoined twins, who were joined together dorsally in lower lumbar and sacral region and had spina bifida and shared a single thecal sac with combined weight of 6.14 kg. Spinal cord was separated at the level of the conus followed by duraplasty. They had uneventful recovery with normal 15 months follow-up. Separation of conjoined twins is recommended in where this is feasible with the anticipated survival of both or one infant.

  19. Heritability of retinal vascular fractals: a twin study

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    Purpose: To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension. Methods: This was a cross-sectional study of 50-degree, disc-centred fundus photographs from 59 monozygotic and 55 dizygotic, same-sex twin pairs aged 20-46 years....... The retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficents. Falconer´s formula and quantitative genetic models were used to determine the genetic component of variation. Results: The retinal...... vascular fractal dimensions were measurable for both twins in 50 monozygotic and 49 dizygotic twin pairs. The mean fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, p=0.06), supporting that the study population was suitable...

  20. Disease-Concordant Twins Empower Genetic Association Studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    concordant for a disease, should confer increased power in genetic association analysis because of their genetic relatedness. We conducted a computer simulation study to explore the power advantage of the disease-concordant twin design, which uses singletons from disease-concordant twin pairs as cases...... of an ordinary case-control design, with variations depending on genetic mode. Importantly, the enriched power for dizygotic twins also applies to disease-concordant sibling pairs, which largely extends the application of the concordant twin design. Overall, our simulation revealed a high value of disease......-concordant twins in genetic association studies and encourages the use of genetically related individuals for highly efficiently identifying both common and rare genetic variants underlying human complex diseases without increasing laboratory cost....

  1. Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort

    DEFF Research Database (Denmark)

    Maas, Iris Lianne; Brüggemann, Petra; Requena, Teresa

    2017-01-01

    PURPOSE: Genetic contributions to tinnitus have been difficult to determine due to the heterogeneity of the condition and its broad etiology. Here, we evaluated the genetic and nongenetic influences on self-reported tinnitus from the Swedish Twin Registry (STR). METHODS: Cross-sectional data from...... the STR was obtained. Casewise concordance rates (the risk of one twin being affected given that his/her twin partner has tinnitus) were compared for monozygotic (MZ) and dizygotic (DZ) twin pairs (N = 10,464 concordant and discordant twin pairs) and heritability coefficients (the proportion of the total...... variance attributable to genetic factors) were calculated using biometrical model fitting procedures. RESULTS: Stratification of tinnitus cases into subtypes according to laterality (unilateral versus bilateral) revealed that heritability of bilateral tinnitus was 0.56; however, it was 0.27 for unilateral...

  2. Blood Chimerism in Dizygotic Monochorionic Twins During 5 Years Observation.

    Science.gov (United States)

    Dziegiel, M H; Hansen, M H; Haedersdal, S; Barrett, A N; Rieneck, K; Main, K M; Hansen, A T; Clausen, F B

    2017-10-01

    Dizygotic monochorionic twin pregnancies can result in blood chimerism due to in utero twin-to-twin exchange of stem cells. In this case, we examined the proportion of allogeneic red blood cells by flow cytometry and the proportion of allogeneic nucleated cells by digital polymerase chain reaction at 7 months and again at 5 years. We found an increase in the proportion of allogeneic cells from 63% to 89% in one twin, and a similar increase in autologous cells in the other twin from 57% to 84%. A paradigm for stem cell therapy could be modeled on this case: induction of tolerance and chimerism by antenatal transfusion of donor stem cells. The procedure would hold the promise of transplantation and tolerance induction without myeloablative conditioning for inheritable benign hematological diseases such as sickle cell disease and thalassemia. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  3. Increased risk of type 2 diabetes in elderly twins

    DEFF Research Database (Denmark)

    Poulsen, Pernille; Grunnet, Louise G; Pilgaard, Kasper

    2009-01-01

    OBJECTIVE: Genetic susceptibility, low birth weight (LBW), and aging are key etiological factors in the development of type 2 diabetes. LBW is common among twins. It is unknown whether twin status per se is associated with risk of type 2 diabetes, and valid concordance rates of type 2 diabetes....... In addition, type 2 diabetes incidence cases in twins (n = 626) and singletons (n = 553) were identified through the National Diabetes Register. RESULTS: Twins were more abdominally obese, insulin resistant, and glucose intolerant, as evidenced by a higher A1C (%) (means +/- SD) (MZ: 6.0 +/- 1.0, DZ: 5...... status per se is associated with abdominal obesity, insulin resistance, and increased prevalence of type 2 diabetes in elderly twins. The data support a quantitatively significant impact of the fetal environment as opposed to genetics on risk of type 2 diabetes....

  4. Twinning in muskox and the cytogenetic investigation of a freemartin

    Directory of Open Access Journals (Sweden)

    N. J. Reindl

    1993-12-01

    Full Text Available The occurrence of twinning has been documented for muskox in both wild and captive populations. Of two known captive twin births only one set survived beyond 120 days. In both cases the twins were male-female pairs and both females showed abnormal sexual development. Two sets of stillborn twins have also been recorded. All four stillborn fetuses were female and none showed anomalies of the reproductive tract upon post-mortem examination. Blood cultures from the surviving male and female twins revealed that both were chimeric, indicating the admixture of fetal blood. Fibroblast cultures were normal for the respective sex of each individual. The freemartin heifer had anatomical abnormalities of the clitoris as well as the secondary sex characteristics of a male.

  5. Cognitive function in unaffected twins discordant for affective disorder

    DEFF Research Database (Denmark)

    Christensen, Maj Vinberg; Kyvik, Kirsten Ohm; Kessing, Lars Vedel

    2006-01-01

    . Cognitive performance of 203 High-Risk and Low-Risk twins was compared. RESULTS: Healthy twins discordant for unipolar disorder showed lower performance on almost all measures of cognitive function: selective and sustained attention, executive function, language processing and working and declarative memory...... impairment found seemed to be related to genetic liability, as the MZ High-Risk twins showed significant impairment on selective and sustained attention, executive function, language processing and working and declarative memory, whereas the DZ High-Risk twins presented with significantly lower scores only......, and also after adjustment for demographic variables, subclinical symptoms and minor psychopathology. Healthy twins discordant for bipolar disorder showed lower performance on tests measuring episodic and working memory, also after adjustment for the above-mentioned covariables. The discrete cognitive...

  6. Conjoined Twins: Philosophical Problems and Ethical Challenges.

    Science.gov (United States)

    Savulescu, Julian; Persson, Ingmar

    2016-02-01

    We examine the philosophical and ethical issues associated with conjoined twins and their surgical separation. In cases in which there is an extensive sharing of organs, but nevertheless two distinguishable functioning brains, there are a number of philosophical and ethical challenges. This is because such conjoined twins: 1. give rise to puzzles concerning our identity, about whether we are identical to something psychological or biological; 2. force us to decide whether what matters from an ethical point of view is the biological life of our organisms or the existence of our consciousness or mind; 3. raise questions concerning when, if ever, it is morally acceptable to sacrifice one of us to save another; 4. force us to reflect on the conditions for ownership of organs and the justification of removal of organs for transplantation which causes the death of the donor; 5. raise questions about who should take decisions about life-risking treatments when this cannot be decided by patients themselves. We examine and suggest answers to these questions. © The Author 2015. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Delivery of the second twin: comparison of two approaches.

    Science.gov (United States)

    Pons, Jean-Claude; Dommergues, Marc; Ayoubi, Jean-Marc; Gélébart, Marie; Papiernik, Emile

    2002-08-05

    To compare two obstetrical approaches toward delivery of the second twin: one of expectant management, and the other, active; to compare the neonatal and maternal results and thereby identify, if possible, the optimal approach. This retrospective study looked at twin births in two maternity units in the Paris, France metropolitan region: Antoine Béclère (AB) in Clamart, and Port-Royal (PR) in Paris and concerned 113 deliveries of pairs of twins at AB and 78 at PR. The mean duration of the interbirth interval was 9 min at AB and 5 min at PR (P < 0.001). The characteristics of the pregnancies and the deliveries of twin A were comparable. Spontaneous birth accounted for 51% of twin A births at AB and 27% at PR (P < 0.001). Intrauterine manipulation of twin B occurred in 2% of the births at AB and 43% at PR (P < 0.001). At AB, there were five cesareans to deliver the second twin, but none at PR. The Apgar scores at AB and PR were identical, at 1 and 5 min, and for births before 32 weeks' gestation as well as for those afterwards. At AB, 19% (n = 21) of second twins were transferred to the neonatal intensive care unit, and at PR, 18% (n = 14). The neonatal results were similar in both groups, even though both the rate of obstetric maneuvers and the interbirth interval differed significantly. The two methods therefore appear to be equivalent when judged by the second twin's neonatal indicators. Our data suggest that an active approach diminishes the likelihood of cesarean delivery for the second twin, without increasing the neonatal risk.

  8. Secular trends in gestational age and birthweight in twins.

    Science.gov (United States)

    Gielen, M; van Beijsterveldt, C E M; Derom, C; Vlietinck, R; Nijhuis, J G; Zeegers, M P A; Boomsma, D I

    2010-09-01

    In recent decades, the overall rate of preterm births has increased. The aim of the present study was to examine whether this trend is also seen for multiple gestations. More specifically, we examined if there has been a decrease in gestational age for live born monozygotic (MZ) and dizygotic (DZ) twins and if there has been a simultaneous change in birthweight. The contributions of fertility treatments and Caesarean sections were taken into consideration. All analyses were carried out in two large European twin cohorts. Cross-sectional study of 6310 live born twin pairs, born between 1964-2007, from the Belgian East Flanders Prospective Twin Survey and 14,712 twin pairs, born between 1990-2006, from the Netherlands Twin Register. Multiple regression analyses were performed with gestational age as outcome variable, and multilevel analysis with birthweight as outcome variable. All analyses were performed with and without adjustment for zygosity, parity, maternal age, mode of conception and delivery and, for the analyses of birthweight, gestational age. Gestational age decreased in a linear fashion from 1964 to 2007 with a decrease of 0.25 days per year in a similar way for MZ and DZ twins. Changes in birthweight depended on gestational age: up to 32 weeks, birthweight decreased and after 32 weeks birthweight increased. The frequency of infertility treatment and Caesarean sections, primiparity and advanced maternal age increased over the years, but none of these factors influenced the secular trends in gestational age and birthweight. The decrease in gestational age and change in birthweight in twins are sources of concern, especially for very preterm twins, for whom birthweight decreased. For twins born after 32 weeks, an increase in birthweight was observed and this is very likely the explanation for the decrease in gestational age.

  9. Trends in the obstetric features and management of twin pregnancies.

    LENUS (Irish Health Repository)

    Smith, K E

    2010-03-01

    There are no reports outlining the trends in obstetric features and clinical management of twin pregnancies in an Irish obstetric population. The aim of this study was to investigate these factors for all twin pregnancies delivered during the 19 year period between 1989 and 2007, at Galway University Hospital (GUH). There were 52,199 infants delivered at GUH, of which 1594 infants (3.05% of births) were twins, related to 797 twin pregnancies. The overall incidence of twin pregnancies was 1.52%, increasing from 0.8%-1.0% in the early years of the study to 1.7-1.8% in the latter years of the study (P<0.001). There was a significant increase in incidence of twins born to mothers aged 30-39 years, alongside a significant reduction to mothers aged 20-29 years (P<0.01). The caesarean section rate overall was 41.5% (331\\/797), of which 54% (n=179) were elective, and 46% (n=152) were emergency, representing an emergency caesarean section rate of 19.1% of all twin pregnancies, and of 24.6% after exclusion of elective caesarean sections. The caesarean section rate for twins increased from 30% in 1989 to greater than 50% in the latter years of the study (P<0.01), related largely to a significant increase in elective caesarean sections (P<0.01). The combined vaginal-caesarean delivery rate was remarkably low at 0.75% of all twin pregnancies, and 1% after exclusion of elective caesarean sections. The preterm delivery rates were 4.1% (<32 weeks), and 16.3% (<36 weeks), with an overall perinatal mortality rate of 37 per 1000. These findings highlight the altered demographic and clinical aspects of twin pregnancies in an Irish obstetric population.

  10. Recurrent twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation: a systematic review of the literature.

    LENUS (Irish Health Repository)

    Walsh, C A

    2012-11-01

    Selective fetoscopic laser photocoagulation (SFLP) is now the treatment of choice for twin-twin transfusion syndrome (TTTS). The incidence of recurrent TTTS following SFLP has been inconsistently reported across different studies. We performed a systematic review of TTTS recurrence following SFLP.

  11. Do MZ twins have discordant experiences of friendship? A qualitative hypothesis-generating MZ twin differences study

    Science.gov (United States)

    Moran, Nicola; Plomin, Robert

    2017-01-01

    Using a qualitative monozygotic (MZ) twin differences design we explored whether adolescent MZ twins report discordant peer relationships and, if so, whether they perceive them as causes, consequences or correlates of discordant behaviour. We gathered free-response questionnaire data from 497 families and conducted in-depth telephone interviews with 97 of them. Within this dataset n = 112 families (23% of the sample) described discordant peer relationships. Six categories of discordance were identified (peer victimisation, peer rejection, fewer friends, different friends, different attitudes to friendship and dependence on co-twin). Participants described peer relationship discordance arising as a result of chance occurrences, enhanced vulnerability in one twin or discordant behaviour. Consequences of discordant peer relationships were seen as discordance in self-confidence, future plans, social isolation, mental health and interests. In all cases the twin with worse peer experiences was seen as having a worse outcome. Specific hypotheses are presented. PMID:28727730

  12. Method and apparatus for jet-assisted drilling or cutting

    Science.gov (United States)

    Summers, David Archibold; Woelk, Klaus Hubert; Oglesby, Kenneth Doyle; Galecki, Grzegorz

    2012-09-04

    An abrasive cutting or drilling system, apparatus and method, which includes an upstream supercritical fluid and/or liquid carrier fluid, abrasive particles, a nozzle and a gaseous or low-density supercritical fluid exhaust abrasive stream. The nozzle includes a throat section and, optionally, a converging inlet section, a divergent discharge section, and a feed section.

  13. Successful fetoscopic laser coagulation for twin-to-twin transfusion syndrome under local anaesthesia.

    LENUS (Irish Health Repository)

    Cooley, S

    2011-06-01

    A review of the efficacy and outcome of fifteen fetoscopic laser ablations under local anaesthesia for twin to twin transfusion syndrome (TTTS) in the National Maternity Hospital Dublin was undertaken. The mean gestation at laser was 19.7 weeks (range 16-25 weeks) with a mean gestation at delivery of 29.1 weeks (range 20-35 weeks). The overall liveborn birth rate was 79% (22 infants) and one pregnancy was still ongoing. There were four neonatal deaths secondary to complications of prematurity. The surviving eighteen infants (64%) undergo regular paediatric review. The procedure was performed successfully in all cases with local anaesthesia. In no case was there maternal discomfort that warranted the procedure to be abandoned and good visual access of the vascular anastamoses was obtained in all cases. Local anaesthesia therefore offers a safe effective anaesthetic option for fetoscopic laser coagulation in monochorionic pregnancies complicated by TTTS.

  14. What is the definition of pulsatile umbilical venous flow in twin-twin transfusion syndrome?

    Science.gov (United States)

    Russell, Zoi; Quintero, Rubén A; Kontopoulos, Eftichia V

    2008-12-01

    The aim of the study was to derive an objective definition of pulsatile umbilical venous flow (PUVF). Pulsed Doppler waveform analysis of the umbilical vein was performed in stages III and IV twin-twin transfusion syndrome (TTTS) patients. In patients with PUVF, the umbilical vein maximum (Vmax) and the umbilical vein minimum velocity (Vmin) and the resistance index for the umbilical vein (UVRI) = (100 x [Vmax - Vmin]/Vmax) were assessed. PUVF was noted in 130 of 226 stages III and IV TTTS patients. Digital images were available for analysis in 65 of 130 patients (50%). The minimum UVRI associated with PUVF was 16% for stages III and IV TTTS. There was a trend for increasing UVRI with stage (P = .052). Stage IV patients were more likely to have an UVRI greater than 30% (P = .02). PUVF can be defined as an UVRI greater than 15%. A scale definition of PUVF may further facilitate assessment of the degree of fetal hemodynamic compromise.

  15. High twin resemblance for sensitivity to hypoxia.

    Science.gov (United States)

    Masschelein, Evi; Van Thienen, Ruud; Thomis, Martine; Hespel, Peter

    2015-01-01

    Physiological responses to hypoxia vary between individuals, and genetic factors are conceivably involved. Using a monozygotic twin design, we investigated the role of genetic factors in physiological responses to acute hypoxia. Thirteen pairs of monozygotic twin brothers participated in two experimental sessions in a normobaric hypoxic facility with a 2-wk interval. In one session, fraction of inspired O2 (FiO2) was gradually reduced to 10.7% (approximately 5300 m altitude) over 5 h. During the next 3 h at 10.7%, FiO2 subjects performed a 20-min submaximal exercise bout (EXSUB, 1.2 W·kg) and a maximal incremental exercise test (EXMAX). An identical control experiment was done in normoxia. Cardiorespiratory measurements were continuously performed, and 8-h urine output was collected. Compared with normoxia, hypoxia decreased (P < 0.05) arterial O2 saturation (%SpO2) at rest (-22%) and during exercise (-28%). Furthermore, V˙O2max (-39%), HRmax (HR, -8%), maximal pulmonary ventilation (V˙Emax, -11%), and urinary norepinephrine excretion (-31%) were reduced (P < 0.05) whereas HR at rest (25%) and during EXSUB (16%) and V˙E at rest (38%) and during EXSUB (70%) were increased (P < 0.05). However, hypoxia-induced changes (Δ) were not randomly distributed between subjects. Between-pair variance was substantially larger than within-pair variance (P < 0.05) for Δ%SpO2 at rest (approximately threefold) and during exercise (approximately fourfold), ΔV˙O2max (approximately fourfold), ΔHR during exercise (approximately seven- to eightfold), hypoxic ventilatory response (approximately sixfold), and Δ urinary norepinephrine output (approximately threefold). Incidence of acute mountain sickness (AMS) also yielded significant twin similarity (P < 0.05). AMS subjects showed approximately 50% greater drop in urinary norepinephrine and lower hypoxic ventilator response than AMS individuals. Our data suggest that genetic factors regulate cardiorespiratory responses, exercise

  16. Investigating Unique Environmental Influences of Parenting Practices on Youth Anxiety: A Monozygotic Twin Differences Study

    Science.gov (United States)

    Chen, Jie; Yu, Jing; Zhang, Jianxin

    2016-01-01

    The associations between parenting practices and adolescent anxiety symptoms were examined in both individual and monozygotic (MZ) twin differences levels. Participants were 804 pairs of Chinese MZ adolescent twins aged 10-18 years (M = 13.57, SD = 2.67, 52% females). Twins' anxiety symptoms were assessed by self- and parent-reports. Twins also…

  17. Successful Separation Of Two Pairs Of Conjoined Twins In Ile Ife ...

    African Journals Online (AJOL)

    Conjoined twins are rare phenomena occurring in one in 1 in 50,000 live births. Successful surgical separation of conjoined twins is a major undertaking requiring careful planning by a multidisciplinary team. Reports of seperation of joined twins in developing countries like Nigeria are rare. Ten cases of conjoined twins ...

  18. Multivariate genetic analysis of atopy phenotypes in a selected sample of twins

    DEFF Research Database (Denmark)

    Thomsen, S F; Ulrik, C S; Kyvik, K O

    2006-01-01

    , airway hyper-responsiveness (AHR), and positive skin prick test (posSPT) in a sample of adult twins. METHODS: Within a sampling frame of 21,162 twin subjects, 20-49 years of age, from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins), who either themselves and...

  19. Heritability of Retinal Vascular Fractals: A Twin Study.

    Science.gov (United States)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line; Hougaard, Jesper Leth; Möller, Sören; Kyvik, Kirsten Ohm; Larsen, Michael; Munch, Inger Christine; Grauslund, Jakob

    2017-08-01

    To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension. This was a cross-sectional study of 50 monozygotic and 49 dizygotic, same-sex twin pairs aged 20 to 46 years. In 50°, disc-centered fundus photographs, the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation. The mean fractal dimension did not differ statistically significantly between monozygotic and dizygotic twin pairs (1.505 vs. 1.495, P = 0.06), supporting that the study population was suitable for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, P = 0.0002) in monozygotic twins than in dizygotic twins (0.108, P = 0.46), corresponding to a heritability h2 for the fractal dimension of 0.79. In quantitative genetic models, dominant genetic effects explained 54% of the variation and 46% was individually environmentally determined. In young adult twins, the branching pattern of the retinal vessels demonstrated a higher structural similarity in monozygotic than in dizygotic twin pairs. The retinal vascular fractal dimension was mainly determined by genetic factors, which accounted for 54% of the variation. The genetically predetermination of the retinal vasculature may affect the retinal response to potential vascular disease in later life.

  20. The Maternal Emotional Climate Predicts Twin Sibling Relationship Quality.

    Science.gov (United States)

    Mark, Katharine M; Pike, Alison; Latham, Rachel M; Oliver, Bonamy R

    2017-04-01

    We investigated the association between maternal expressed emotion and twin relationship quality, after controlling for a maternal questionnaire measure of the mother-child relationship. This was explored within a community sample of 156 mothers and their two young twin children (M child age = 3.69 years; SD child age = 0.37). Mothers reported on the twin-twin relationship and the mother-child relationship via questionnaire. They were also interviewed about each child using the innovative Preschool Five Minute Speech Sample (Daley et al., 2003), which yields information about relative positive:negative maternal expressed emotion. Mothers who expressed more family-wide positive emotion and less family-wide negative emotion also reported more positivity, but not negativity, within the twin relationship - even when controlling for questionnaire reports of the mother-child relationship. Counter to expectations, discrepancies in mothers' expressed emotion between their twins also predicted more positive sibling relationships. Our findings corroborate the well established spill-over effect, whereby families are viewed as emotional units of interdependent individuals, none of whom can be understood in isolation from one another. Most importantly, the Preschool Five Minute Speech Sample provides information about mothering that questionnaire reports may not, and thus it is a useful tool in better understanding the twin family system.

  1. Socio-psycho-historical observation on the twin

    International Nuclear Information System (INIS)

    Watanabe, Shoji; Satow, Yukio; Ueoka, Hiroshi; Munaka, Masaki; Kurihara, Minoru

    1980-01-01

    The so-called ''twin control study'', mainly on the monozygotic twins one of which was A-bomb exposed and the other was non-exposed were carried out. Sampling was conducted utilizing the materials as follows: 1) The survey on casualities of A-bomb exposed families in Hiroshima which was undertaken in 1946. 2) The survey of A-bomb survivors in 1965. 3) A-bomb exposed family survey conducted between 1973 to 1975. 4) Investigations of A-bomb victims exposed in the proximal areas from the hypocenter. From the above mentioned materials 470 pairs were selected, of which 220 were exposed. Among them 172 pairs were twins of the same sex. Female and male pair were also employed. In one case they were exposed, while the others were nonexposed. Two pairs were examined under the following methods: 1) Depth interview to ascertain familial casualities with reference to the family life cycle. 2) Socio-historical research. 3) Motoaki's Jinkaku Shindan Kensa (Modified Rorschach test by H. Motoaki), and T.A.T. test. Results obtained were summarized as follows: 1) Both pairs of twins were similar appearance, and also personality traits, and had a strong feeling of companionship for each other. 2) In family relationships, the persons studied were very conscious of the role expectations of elder and younger siblings in the twin pairs. 3) Through depth interview and projective test, A-bomb exposed pairs still showed deep psychological stresses, resulting from the A-bomb disaster. 4) Both among the exposed twins and within the nonexposed control group twin siblings had a close feeling of companionship for each other. However, nonexposed twins could not understand the psychological experience of twins who had been subjected to the atomic disaster. (author)

  2. The Child and Adolescent Twin Study in Sweden (CATSS).

    Science.gov (United States)

    Anckarsäter, Henrik; Lundström, Sebastian; Kollberg, Linnea; Kerekes, Nora; Palm, Camilla; Carlström, Eva; Långström, Niklas; Magnusson, Patrik K E; Halldner, Linda; Bölte, Sven; Gillberg, Christopher; Gumpert, Clara; Råstam, Maria; Lichtenstein, Paul

    2011-12-01

    The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive-compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems.

  3. Trial of labour in twin pregnancies: a retrospective cohort study.

    Science.gov (United States)

    de Castro, H; Haas, J; Schiff, E; Sivan, E; Yinon, Y; Barzilay, E

    2016-05-01

    To assess the success rate of vaginal delivery among women with twin pregnancies; the Twin Birth Study has shown that vaginal delivery and caesarean section are equally safe for twin delivery but >40% of the planned vaginal delivery group delivered by caesarean section. A retrospective cohort study. A tertiary medical centre. A total of 2194 women with twin pregnancies not complicated with very low birthweight. Planned mode of delivery was documented in the woman's electronic record upon entering the delivery room. Information regarding maternal age at delivery, parity, gestational age, presentation, previous history of caesarean delivery, birthweight and Apgar score was collected from the obstetric electronic charts. Rate of vaginal twin delivery. Of the 2194 women included, 1311 twin pregnancies had planned caesarean delivery and 883 underwent a trial of labour. Of the 883 women who underwent a trial of labour, the rate of vaginal delivery was 86.9%, whereas the rates of caesarean delivery and combined vaginal-caesarean delivery were 11.1% and 2.0%, respectively. Presentation of second twin, gestational age and maternal age did affect the chances of success. Nulliparity [odds ratio (OR) 2.38, 95% confidence interval (95% CI) 1.4-4.05], Foley induction of labour (OR 2.33, 95% CI 1.38-3.91) and body mass index >30 kg/m(2) (OR 1.76, 95% CI 1.03-3) were independent risk factors for caesarean delivery. The rate of vaginal delivery among women with twin pregnancies who undergo labour can be high, especially in women who laboured spontaneously and have delivered before. The rate of vaginal delivery of twins can be high, especially in women who have delivered before. © 2015 Royal College of Obstetricians and Gynaecologists.

  4. Strain rate sensitivity and evolution of dislocations and twins in a twinning-induced plasticity steel

    International Nuclear Information System (INIS)

    Liang, Z.Y.; Wang, X.; Huang, W.; Huang, M.X.

    2015-01-01

    The present work investigated the effect of strain rates (10 −3 to 10 3 s −1 ) on the deformation behaviour of a twinning-induced plasticity (TWIP) steel. The strain rate sensitivity was studied in terms of instantaneous strain rate sensitivity (ISRS) and strain rate sensitivity of work-hardening (SRSW). While ISRS concerns the instantaneous flow stress change upon strain rate jump, SRSW deals with the subsequent modification in microstructure evolution, i.e. change of work-hardening rate. The present TWIP steel demonstrates a positive ISRS which remains stable during deformation and a negative SRSW, i.e. lower work-hardening rate at higher strain rate. Synchrotron X-ray diffraction experiments indicate that the negative SRSW should be attributed to the suppression of dislocations and deformation twins at high strain rate. This unexpected finding is different to conventional face-centred cubic (fcc) metals which generally show enhanced work-hardening rate at higher strain rate. A constitutive model which is strain rate- and temperature-dependent is developed to explain the stable ISRS and the negative SRSW. The modelling results reveal that the stable ISRS should be attributed to the thermally-activated dislocation motion dominated by interstitial carbon atoms and the negative SRSW should be due to the suppression of the dislocations and deformation twins caused by the adiabatic heating associated with high strain rate deformation

  5. Predictors of 2-year cognitive performance after laser surgery for twin-twin transfusion syndrome.

    Science.gov (United States)

    Vanderbilt, Douglas L; Schrager, Sheree M; Llanes, Arlyn; Hamilton, Anita; Seri, Istvan; Chmait, Ramen H

    2014-10-01

    The purpose of this study was to determine risk factors for poor cognitive performance among children who are treated with in utero selective laser photocoagulation of communicating vessels for twin-twin transfusion syndrome. This was a prospectively enrolled cohort study. Cognitive performance at age 2 years (±6 weeks) was assessed with the Battelle Developmental Inventory 2nd Edition (BDI-2). Multilevel regression models evaluated risk factors for poor cognitive performance at shared (pregnancy) and individual (child) levels. In addition to development, blindness, deafness, and cerebral palsy were assessed based on physical examination. A priori power analysis determined that a sample of ≥100 children was required for adequate statistical power (0.80). One hundred children (57 families) were evaluated. Total BDI-2 score was within normal range (mean, 101.3 ± [SD]12.2); 1 child had a BDI-2 score of cognitive outcomes. Donor/recipient status, gestational age at surgery, fetal growth restriction, and co-twin fetal death were not risk factors. The rate of neurodevelopmental impairment (blindness, deafness, cerebral palsy, and/or a BDI-2 score cognitive performance quotients were in the normal range, with risk factors for poor outcomes seen at the pregnancy and child levels. Clinical and socioeconomic characteristics can identify at-risk children who need additional interventions. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Twin-twin transfusion syndrome: neurodevelopment of infants treated with laser surgery

    Directory of Open Access Journals (Sweden)

    Denise Campos

    2016-04-01

    Full Text Available ABSTRACT Objective To assess the neurodevelopmental functions of survivors of twin-twin transfusion syndrome (TTTS treated by fetoscopic laser coagulation (FLC, during the first year of life, comparing them to a control group; and to verify the influence of specific variables on neurodevelopment. Method This was a prospective, longitudinal study. The sample comprised 33 monochorionic diamniotic twins who underwent FLC for treatment of TTTS and 22 full-term infants of single-fetus pregnancies. Bayley Scales of Infant and Toddler Development Screening Test were used for evaluation. Prenatal, perinatal and postnatal information were obtained. Results There was an increased frequency of infants in the TTTS group with inadequate performance compared to the control group. The identified variables (fetal donor, low economic income and cardiorespiratory disease negatively impacted expressive communication and fine motor skills. Conclusion Although through follow-up is recommended in all TTTS survivors, particular attention is required for the high-risk group as defined in this study.

  7. In Situ Studies on the Irradiation-Induced Twin Boundary-Defect Interactions in Cu

    Science.gov (United States)

    Fan, C.; Li, Jin; Fan, Zhe; Wang, H.; Zhang, X.

    2017-11-01

    Polycrystalline Cu films with nanoscale annealing twins are subjected to in situ Kr++ ion irradiation at room temperature inside a transmission electron microscope up to a dose of 1 displacement-per-atom. Radiation induces prominent migration of incoherent twin boundaries. Depending on twin thickness, three types of twin boundary evolutions are observed, including rapid detwinning, gradual detwinning, and self-healing. The mechanism of twin thickness-dependent evolution of microstructures is discussed. This study provides further evidence on twin boundary-defect interactions and may assist the design of radiation-tolerant twinned metallic materials.

  8. Cesarean Section for the Second Twin

    DEFF Research Database (Denmark)

    Engelbrechtsen, Line; Nielsen, Elise Hoffmann; Perin, Trine

    2013-01-01

    deliveries. Data were extracted from medical records, a fetal medicine software program (Astraia), and the National Birth Registry. Short-term poor neonatal outcome was measured as a 5-minute Apgar score ≤ 7, umbilical cord pH ≤ 7.10, and admission to neonatal intensive care unit for more than 3 days....... RESULTS: Vertex-nonvertex fetal presentations were more prevalent in combined deliveries than vaginal deliveries (OR 4.4, 2.5-7.8). Nonvertex second twins born by combined delivery had a higher risk of Apgar score ≤ 7 and umbilical cord pH ≤ 7.10 compared with vaginal delivery, unadjusted OR 6.2 (2...

  9. Twin Peaks in 360-degree panorama

    Science.gov (United States)

    1997-01-01

    The prominent hills dubbed 'Twin Peaks' approximately 1-2 kilometers away were imaged by the Imager for Mars Pathfinder (IMP) as part of a 360-degree color panorama, taken over sols 8, 9 and 10. A lander petal and deflated airbag are at the bottom of the image.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  10. Dancing Twins: Stellar Hierarchies That Formed Sequentially?

    Science.gov (United States)

    Tokovinin, Andrei

    2018-04-01

    This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer component. Such systems could be formed either sequentially (inside-out) by disk fragmentation with subsequent accretion and migration, or by a cascade hierarchical fragmentation of a rotating cloud. Orbits of the outer and inner subsystems are computed or updated in four such hierarchies: LHS 1070 (GJ 2005, periods 77.6 and 17.25 years), HIP 9497 (80 and 14.4 years), HIP 25240 (1200 and 47.0 years), and HIP 78842 (131 and 10.5 years).

  11. The story of antimatter matter's vanished twin

    CERN Document Server

    Borissov, Guennadi

    2018-01-01

    Each elementary particle contained within every known substance has an almost identical twin called its antiparticle. Existing data clearly indicate that equal numbers of particles and antiparticles were initially created soon after the birth of the universe. Despite this, all objects around us, as well as all the stars in all the known galaxies, are made of particles, while antiparticles have almost completely vanished. The reasons behind this disappearance are not yet fully known. Uncovering them will allow us to not only penetrate much deeper into the structure of matter, but also to understand the secret mechanisms that determine the genesis and development of our immense universe. That is why explaining the mystery of the missing antimatter is currently considered to be one of the main tasks of particle physics. This book tells the story of all the achievements in solving the problem of the missing antiparticles including the latest developments in the field. It is written by Prof. Guennadi Borissov, an...

  12. Caracterização de solda de revestimento de AWS 317L depositados por GMAW duplo arame em aços ASTM a 516 gr 60 para uso na indústria do petróleo Characterization of the AWS 317L weld overlay applied by twin wire GMAW on ASTM a516 gr 60 steel used in oil and gas industry

    Directory of Open Access Journals (Sweden)

    Marcos Mesquita da Silva

    2010-09-01

    Full Text Available Este trabalho teve como objetivo avaliar as características microestruturais de revestimentos aplicados por soldagem utilizando-se o processo GMAW com duplo arame e o metal de adição AWS E317L sobre metal de base ASTM A 516 Gr 60. Durante as soldagens empregou-se dois níveis de energia de soldagem (1170kJ/m e 1530kJ/m, um gás de proteção correspondendo a uma mistura de argônio e oxigênio (95% Ar e 5% O2 e uma temperatura interpasse de 150ºC. Em seguida, as amostras foram caracterizadas utilizando-se ensaios de microscopia ótica e microdureza. Os resultados obtidos indicaram um aumento na diluição e na extensão da zona termicamente afetada (ZTA com o aumento da energia de soldagem. Além disso, também houve a formação de zonas parcialmente diluídas (ZPD na interface revestimento/substrato, apresentando valores acima de 300HV. A quantidade de ZPD também foi maior para o nível de energia de soldagem mais elevado.The aim of this study was to evaluate the metallurgical characteristics of weld overlay applied by Twin Wire GMAW process and the AWS E317L filler metal on ASTM A 516 Gr 60 base metal. During welding it was employed two levels of heat input (H = 1170kJ/m and H = 1530kJ/m and a mixture of argon and oxygen (95% Ar and 5% O2 as shielding gas. Besides, all welds were carried out without preheat, however, an interpass temperature of 150ºC was used. Then, the specimens were characterized using optical microscopy and microhardness tests. The results showed an increase in dilution and heat affect zone extension when the heat input increases. Moreover, there was also the formation of partially diluted zones (PDZ along the fusion line, presenting values above 300HV. The formation of PDZ was larger for the highest heat input level.

  13. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    Directory of Open Access Journals (Sweden)

    Eric J. Tuegel

    2011-01-01

    Full Text Available Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the life of aircraft structure and assuring its structural integrity is presented. The technical challenges to developing and deploying a Digital Twin are discussed in detail.

  14. Twin removal in digital holography using diffuse illumination.

    Science.gov (United States)

    Monaghan, David S; Kelly, Damien P; Pandey, Nitesh; Hennelly, Bryan M

    2009-12-01

    A method to numerically remove the twin image for inline digital holography, using multiple digital holograms, is discussed. Each individual hologram is recorded by using a statistically independent speckle field to illuminate the object. If the holograms are recorded in this manner and then numerically reconstructed, the twin image appears as a different speckle pattern in each of the reconstructions. By performing speckle-reduction techniques the presence of the twin image can be greatly reduced. A theoretical model is developed, and experimental results are presented that validate this approach. We show experimentally that the dc object intensity term can also be removed by using this technique.

  15. Validation of Quench Simulation and Simulation of the TWIN Solenoid

    CERN Document Server

    Pots, Rosalinde Hendrika

    2015-01-01

    For the Future Circular Collider at CERN a multi-purpose detector is proposed. The 6T TWIN Solenoid, a very large magnet system with a stored energy of 53 GJ, is being designed. It is important to protect the magnet against quenches in the system. Therefore several existing quench protection systems are evaluated and simulations have be performed on quenches in the TWIN Solenoid. The simulations on quenches in the TWIN Solenoid have been performed with promising results; the hotspot temperatures do not exceed 120 K and layer to layer voltages stay below 500 V. Adding quench heaters to the system might improve the quench protection system further.

  16. Dissecting complex phenotypes using the genomics of twins

    DEFF Research Database (Denmark)

    Tan, Qihua; Ohm Kyvik, Kirsten; Kruse, Torben A

    2010-01-01

    of human diseases. Besides, twins not only serve as ideal samples for disease gene mapping using conventional genetic markers but also represent an excellent model for associating DNA copy number variations, a structural genetic marker, with human diseases. It is believed that, with the rapid development...... in biotechniques and new advances in bioinformatics, the unique samples of twins will make new contributions to our understanding of the nature and nurture in complex disease development and in human health. This paper aims at summarizing the new uses of twins in current genetic studies and suggesting novel...

  17. Pygopagus Conjoined Twins for Separation Surgery: an Interesting Experience

    Directory of Open Access Journals (Sweden)

    Sanwatsarkar Sadhana

    2013-05-01

    Full Text Available Conjoined twins are rarely encountered in the clinical practice of the anaesthetist and the issues that have to be considered in their anaesthetic management are unique and fascinating. Pygopagus are one of the rare type of conjoined twins with only a handful of cases reported in the literature. We present the case of one and half month old male pygopagus conjoined twins who were joined together dorsally in lower lumbar and sacral region and shared a single thecal sac. They were brought to our hospital for separation surgery.

  18. Twinning in Zircon: Not a High-Pressure Phenomenon

    Science.gov (United States)

    Jones, G. A.; Moser, D.; Shieh, S. R.; Barker, I.

    2017-12-01

    Microtwins in zircon are commonly found in shocked terrestrial and extraterrestrial samples and are potentially important for shock history and crater reconstruction. Twinning is easily observed with both the optical microscope and variety of electron beam techniques. Twinning as a deformation mechanism is consistent with the high strain rates generated during impact. No constitutive relationships, or even general limits on the physical conditions required for twinning in zircon are known, however. Present speculation on the critical quantity for twin formation, i.e. 10s of GPa of shock pressure (Moser et al. 2011, Timms et al., 2012), has no basis in the underlying mechanisms of twin nucleation, which are related to the motion of dislocations. This erroneous value is due to conflation of twinning sensu stricto with a phase transformation to reidite. Reidite occurs as twin-like lamellae occupying the {112} planes which are thought to be a mirror plane for twinning. We review the crystallographic theory of twinning in zircon. We then evaulate several theories on the nucleation of twins along with their necessary stresses involved. Our aim is to show that shock microtwins in zircon can be a `low pressure' shock phenomenon. This 'low pressure' hypothesis is supported by natural samples. These zircons are from the lower crust nearly 80 km from the centre of the Vredefort impact structure—the most distal zircon shock microstructures yet found in the lithosphere. Twins are present in 10% of the zircon grains greater than 50 µm in diameter. As an extensive, 'low pressure' phenomenon, twins are an easily recognized and potentially widespread record of Earth's impact history.Moser, D.E., Cupelli, C. L., Barker, I., Flowers, R. M., Mowman, J. R., Wooden, J. and Hart, R. (2011) New zircon shock phenomena and their use for dating and […] analysis of the Vredefort dome, Canadian Journal of Earth Sciences 48(2), 117-139.Timms, N.E., Reddy, S. M., Healy, D., Nemchin, A. A

  19. Association between obesity and asthma in a twin cohort

    DEFF Research Database (Denmark)

    Thomsen, SF; Ulrik, Charlotte Suppli; Kyvik, KO

    2007-01-01

    Background: Obesity is linked to asthma in a yet poorly understood manner. We examined the relationship between obesity and asthma in a population-based sample of twins. Methods: From the cohorts born between 1953 and 1982, who were enrolled in The Danish Twin Registry, a total of 29 183 twin ind...... to obesity and asthma were significantly correlated only in females, r = 0.28 (0.16-0.38). Conclusions: Obese subjects have an increased risk for asthma, which in females seems partly because of common genes....

  20. Solar Twins and the Barium Puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Arumalla B. S.; Lambert, David L., E-mail: bala@astro.as.utexas.edu [W.J. McDonald Observatory and Department of Astronomy, The University of Texas at Austin, Austin, TX 78712-1205 (United States)

    2017-08-20

    Several abundance analyses of Galactic open clusters (OCs) have shown a tendency for Ba but not for other heavy elements (La−Sm) to increase sharply with decreasing age such that Ba was claimed to reach [Ba/Fe] ≃ +0.6 in the youngest clusters (ages < 100 Myr) rising from [Ba/Fe] = 0.00 dex in solar-age clusters. Within the formulation of the s -process, the difficulty to replicate higher Ba abundance and normal La−Sm abundances in young clusters is known as the barium puzzle. Here, we investigate the barium puzzle using extremely high-resolution and high signal-to-noise spectra of 24 solar twins and measured the heavy elements Ba, La, Ce, Nd, and Sm with a precision of 0.03 dex. We demonstrate that the enhanced Ba ii relative to La−Sm seen among solar twins, stellar associations, and OCs at young ages (<100 Myr) is unrelated to aspects of stellar nucleosynthesis but has resulted from overestimation of Ba by standard methods of LTE abundance analysis in which the microturbulence derived from the Fe lines formed deep in the photosphere is insufficient to represent the true line broadening imposed on Ba ii lines by the upper photospheric layers from where the Ba ii lines emerge. Because the young stars have relatively active photospheres, Ba overabundances most likely result from the adoption of a too low value of microturbulence in the spectrum synthesis of the strong Ba ii lines but the change of microturbulence in the upper photosphere has only a minor affect on La−Sm abundances measured from the weak lines.

  1. Solar Twins and Stellar Maunder Minima

    Science.gov (United States)

    Hall, Jeffrey C.

    2012-05-01

    In 1966, Olin C. Wilson undertook an answer to the question “Does the chromospheric activity of main-sequence stars vary with time, and if so, how?”, initiating the so-called HK Project at Mount Wilson Observatory, which resulted in a magnificent 43-year data set and which has spawned a number of complementary synoptic programs in both hemispheres. Subsequent developments, in particular the realization that activity controls angular momentum evolution in the stars and Sun, that solar activity modulates irradiance, and that there was a pronounced response of terrestrial climate to the Maunder Minimum, spurred efforts to identify solar twins, stars that Giusa Cayrel de Strobel required to possess “fundamental physical parameters very similar, if not identical to those of the Sun.” Non-cycling states appear to occur in the Mount Wilson stars and in other synoptic data with about the same frequency that the Sun’s grand minima occur in the long-term proxy record, suggesting that stellar analogs of the Maunder Minimum may be used to guide understanding of the Sun’s state in the late seventeenth century and, as appears possible given the extended Cycle 23/24 minimum, in the near future. However, the magnitude limits of the existing surveys have kept the sample of solar twins small and long-term monitoring programs have only recently begun to accumulate good time-domain data beyond the canonical HK-index. Addressing these and other issues toward understanding prolonged stellar minima is therefore a key area of inquiry in solar-stellar connection work for the next decade. I will summarize the state of the field and the most promising lines of work for the immediate future. I and my colleagues Wes Lockwood and Brian Skiff sincerely appreciate the National Science Foundation’s long-time support of stellar cycles work at Lowell Observatory.

  2. Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts.

    Science.gov (United States)

    Silventoinen, Karri; Jelenkovic, Aline; Latvala, Antti; Sund, Reijo; Yokoyama, Yoshie; Ullemar, Vilhelmina; Almqvist, Catarina; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Kandler, Christian; Honda, Chika; Inui, Fujio; Iwatani, Yoshinori; Watanabe, Mikio; Rebato, Esther; Stazi, Maria A; Fagnani, Corrado; Brescianini, Sonia; Hur, Yoon-Mi; Jeong, Hoe-Uk; Cutler, Tessa L; Hopper, John L; Busjahn, Andreas; Saudino, Kimberly J; Ji, Fuling; Ning, Feng; Pang, Zengchang; Rose, Richard J; Koskenvuo, Markku; Heikkilä, Kauko; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Sung, Joohon; Kim, Jina; Lee, Jooyeon; Lee, Sooji; Nelson, Tracy L; Whitfield, Keith E; Tan, Qihua; Zhang, Dongfeng; Llewellyn, Clare H; Fisher, Abigail; Burt, S Alexandra; Klump, Kelly L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Medland, Sarah E; Martin, Nicholas G; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Dahl Aslan, Anna K; Corley, Robin P; Huibregtse, Brooke M; Öncel, Sevgi Y; Aliev, Fazil; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Catharina E M; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas S; Rasmussen, Finn; Tynelius, Per; Baker, Laura A; Tuvblad, Catherine; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Gatz, Margaret; Butler, David A; Lichtenstein, Paul; Goldberg, Jack H; Harden, K Paige; Tucker-Drob, Elliot M; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Franz, Carol E; Kremen, William S; Lyons, Michael J; Maia, José A; Freitas, Duarte L; Turkheimer, Eric; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko

    2017-10-01

    Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.

  3. Anorexia and bulimia nervosa in same-sex and opposite-sex twins: lack of association with twin type in a nationwide study of Finnish twins.

    Science.gov (United States)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-12-01

    The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Finnish twins (N=2,426 women, N=1,962 men with known zygosity) from birth cohorts born 1974-1979 were assessed at age 22 to 28 years with a questionnaire for eating disorder symptoms. Based on the questionnaire screen, women (N=292), men (N=53), and their cotwins were interviewed to assess diagnoses of anorexia nervosa and bulimia nervosa (per DSM-IV and broad criteria). In women from opposite-sex twin pairs, the prevalence of DSM-IV or broad anorexia nervosa was not significantly different than that of women from monozygotic pairs or same-sex dizygotic pairs. Of the five male anorexia nervosa probands, only one was from an opposite-sex twin pair. Bulimia nervosa in men was too rare to be assessed by zygosity; the prevalence of DSM-IV or broad bulimia nervosa did not differ in women from opposite- versus same-sex twin pairs. In both sexes, the overall profile of indicators on eating disorders was rather similar between individuals from opposite- and same-sex pairs. The authors found little evidence that the risk for anorexia nervosa, bulimia nervosa, or disordered eating was associated with zygosity or sex composition of twin pairs, thus making it unlikely that in utero femininization or masculinization or socialization effects of growing up with an opposite-sex twin have a major influence on the later development of eating disorders.

  4. Objective assessment of facial skin aging and the associated environmental factors in Japanese monozygotic twins

    OpenAIRE

    Ichibori, Ryoko; Fujiwara, Takashi; Tanigawa, Tomoko; Kanazawa, Shigeyuki; Shingaki, Kenta; Torii, Kosuke; Tomita, Koichi; Yano, Kenji; Sakai, Yasuo; Hosokawa, Ko

    2014-01-01

    Twin studies, especially those involving monozygotic (MZ) twins, facilitate the analysis of factors affecting skin aging while controlling for age, gender, and genetic susceptibility. The purpose of this study was to objectively assess various features of facial skin and analyze the effects of environmental factors on these features in MZ twins. At the Osaka Twin Research Center, 67 pairs of MZ twins underwent medical interviews and photographic assessments, using the VISIA® Complexion Analys...

  5. Renal function in neonates with twin-twin transfusion syndrome treated with or without fetoscopic laser surgery.

    Science.gov (United States)

    Verbeek, Lianne; Joemmanbaks, Faiez A; Quak, Jacoba M E; Sukhai, Ram N; Middeldorp, Johanna M; Oepkes, Dick; Lopriore, Enrico

    2017-09-01

    The aim of this study is to investigate the short-term renal function in neonates with twin-twin transfusion syndrome (TTTS), treated with fetoscopic laser surgery (laser group) or conservatively (non-laser group). Creatinine and urea levels and urine output were recorded in the first week after birth. Primary outcome was short-term renal dysfunction, defined as a creatinine level of >100 μmol/L during the first week postpartum. We evaluated 312 twins (laser group, n = 274; non-laser group, n = 38). Median creatinine and urea levels were lower in the laser group than in the non-laser group (71 versus 82 μmol/L, p = 0.002). Short-term renal dysfunction was lower in the laser group compared to the non-laser group (7.2 versus 34.4%, p < 0.001). Within the laser group, creatinine levels were significantly higher in the subgroup with incomplete laser surgery compared to twins with successful laser surgery (76 versus 69 μmol/L, p = 0.018). No differences were found between donors and recipients except for a higher incidence of oliguria in donors in the non-laser group on day 1. Short-term renal dysfunction occurs less frequently in TTTS twins treated with fetoscopic laser coagulation, particularly after complete surgery, suggesting that laser surgery may have a protective effect on renal function. What is Known: • Antenatally, donor twins in TTTS have severe oliguria due to chronic hypovolemia and impaired renal perfusion • Postnatally, donor twins may suffer from severe renal complications, particularly in TTTS twins treated conservatively. What is New: • The incidence of short-term renal failure in TTTS twins treated with complete laser surgery is low. • After incomplete laser surgery, the incidence of short-term renal dysfunction is increased.

  6. Novel ferrite–austenite duplex lightweight steel with 77% ductility by transformation induced plasticity and twinning induced plasticity mechanisms

    International Nuclear Information System (INIS)

    Sohn, Seok Su; Choi, Kayoung; Kwak, Jai-Hyun; Kim, Nack J.; Lee, Sunghak

    2014-01-01

    The need for lightweight materials has been an important issue in automotive industries to reduce greenhouse gas emission and to improve fuel efficiency. In addition, automotive steels require an excellent combination of strength and ductility to sustain automotive structures and to achieve complex shapes, but the traditional approach to obtain a reduction in weight from down-gauged steels with high strength has many limitations. Here, we present a new ferrite–austenite duplex lightweight steel containing a low-density element, Al; this steel exhibits tensile elongation up to 77% as well as high tensile strength (734 MPa). The enhanced properties are attributed to the simultaneous formation of deformation-induced martensites and deformation twins and the additional plasticity due to deformation twinning in austenite grains having optimal mechanical stability. The present work gives a promise for automotive applications requiring excellent properties as well as reduced specific weight

  7. Spontaneous unilateral Twin Ectopic Pregnancy: A case report

    Directory of Open Access Journals (Sweden)

    هادی اریا منش

    2017-03-01

    Full Text Available Abstract Aim & Objective: Twin pregnancy in the tube is a few and due to more frequent use of ovulatory medicine and increased maternal mortality rate. In this article, we report a case of  untitled twin ectopic pregnancy. Case study: The pregnant women was a 28 year-old  to had  a  history infertility, PCOD, Abortion and cortege,   too have one 5 years girl by CS and  Mild cramp pain in both abdominal lower quadrants and metroreghia . That have not treatment by projection. The ultra-sonography showed a twin pregnancy uterus with a moderate amount of fluid in pelvic cavity was seen. And do salpanjectimy surgery. Conclusion:  We report one Untitled Spontaneous Twin Ectopic Pregnancy,  is necessary any pregnant woman with  positive BhCG and metrorhoghia must be considered for Ectopic pregnancy. To decrease maternal mortality rate. Key words:

  8. Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins

    DEFF Research Database (Denmark)

    Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra

    2015-01-01

    STUDY OBJECTIVES: Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins....... SETTING: Academic clinical research center. PARTICIPANTS: 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). DESIGN: Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a "normal" (7-9 h/24) and "short" (sleeping...... structure to assess within-pair effects of sleep duration on mtDNA copy number. MEASUREMENTS AND RESULTS: Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P sleep efficiency (β = 0.51; 95% CI 0...

  9. A Twin Study on Perceived Stress, Depressive Symptoms, and Marriage

    Science.gov (United States)

    Beam, Christopher R.; Dinescu, Diana; Emery, Robert E.; Turkheimer, Eric

    2017-01-01

    Marriage is associated with reductions in both perceived stress and depressive symptoms, two constructs found to be influenced by common genetic effects. A study of sibling twins was used to test whether marriage decreases the proportion of variance in depressive symptoms accounted for by genetic and environmental effects underlying perceived stress. The sample consisted of 1,612 male and female twin pairs from the University of Washington Twin Registry. The stress-buffering role of marriage was tested relative to two unmarried groups: the never married and the divorced. Multivariate twin models showed that marriage reduced genetic effects of perceived stress on depressive symptoms, but did not reduce environmental effects. The findings suggest a potential marital trade-off for women: Access to a spouse may decrease genetic effects of perceived stress on depressive symptoms, although marital and family demands may increase environmental effects of perceived stress on depressive symptoms. PMID:28661771

  10. Dicephalus dipus tribrachius: A case report of unusual conjoined twins

    Directory of Open Access Journals (Sweden)

    Aparna C

    2010-10-01

    Full Text Available A conjoined twin is a rarity. It occurs 1 in 50,000 to 1 in 2,00,000 fetuses. Forty percent of the conjoined twins are stillborn and an additional one-third die within 24 h of birth. They result from late twinning events about 14th day after fertilization. We report a case of stillborn conjoined twins sent for autopsy. The bodies of the fetuses were fused from the thorax to the pelvis. There were two heads, three upper limbs and two lower limbs, with fusion of the thoracic, abdominal and pelvic regions. On systemic examination, some organs were fused and some were separate. A multilocular cyst with milky fluid was seen in the pelvic region. This case is reported in view of its rarity.

  11. Dicephalus parapagus conjoined twins discordant for anencephaly: a case report

    Directory of Open Access Journals (Sweden)

    Udo Jacob J

    2010-02-01

    Full Text Available Abstract Introduction Cases of conjoined twins occur so rarely that it is important to learn as much as possible from each case. Case presentation We present a case of 9-hour-old, female, Nigerian dicephalus parapagus conjoined twins discordant for anencephaly diagnosed only after the birth of the twins. The anencephalic twin was stillborn while the normal one died within 9 hours of birth from cardiopulmonary failure. Conclusion Many congenital defects of interest can now be detected before birth. A severe lesion such as that found in our index case, which is incompatible with postnatal life, requires counselling. If detected early enough during a properly monitored antenatal care, it may indicate termination of pregnancy.

  12. Twinning structures in near-stoichiometric lithium niobate single crystals

    International Nuclear Information System (INIS)

    Yao, Shuhua; Chen, Yanfeng

    2010-01-01

    A near-stoichiometric lithium niobate single crystal has been grown by the Czochralski method in a hanging double crucible with a continuous powder supply system. Twins were found at one of the three characteristic growth ridges of the as-grown crystal. The twin structure was observed and analyzed by transmission synchrotron topography. The image shifts ΔX and ΔY in the transmission synchrotron topograph were calculated for the 3 anti 2 anti 12 and 0 anti 222 reflections based on results from high-resolution X-ray diffractometry. It is confirmed that one of the {01 anti 1 anti 2} m planes is the composition face of the twin and matrix crystals. The formation mechanism of these twins is discussed. (orig.)

  13. Heredity In Sarcoidosis - A Registry-Based Twin Study

    DEFF Research Database (Denmark)

    Sverrild, Asger; Backer, Vibeke; Kyvik, Kirsten Ohm

    2008-01-01

    BACKGROUND: Sarcoidosis is a multiorgan, granulomatous, inflammatory disease with unknown aetiology. Familial clustering of cases and ethnic variation in the epidemiology suggests a genetic influence on the disease susceptibility. AIM: This paper reports twin concordance and heritability estimate...

  14. Maternal 25-hydroxyvitamin d and preterm birth in twin gestations.

    LENUS (Irish Health Repository)

    Bodnar, Lisa M

    2013-07-01

    To assess whether there was an independent association between maternal 25-hydroxyvitamin D concentrations at 24-28 weeks of gestation and preterm birth in a multicenter U.S. cohort of twin pregnancies.

  15. Outcomes of preterm premature rupture of membranes in twin pregnancies.

    Science.gov (United States)

    Trentacoste, Stephanie V; Jean-Pierre, Claudel; Baergen, Rebecca; Chasen, Stephen T

    2008-08-01

    To describe outcomes in twin pregnancies with preterm premature rupture of membranes (PPROM). Dichorionic twin pregnancies complicated by PPROM at premature rupture of membranes (PROM), latency from PROM to delivery, and infection were examined. In 49 twin pregnancies, the median gestational age at PROM was 31 weeks with a median latency between PROM and delivery of 0 days (interquartile range 0-6). Latency intervals of >or=2 and >or=7 days were achieved by 40.8% and 22.4%, respectively. PPROM at or= 2 days (70.6% vs. 25.0%) and >or=7 days (47.1% vs. 9.4%). There was a significant relationship between latency and clinical and histologic signs of infection. After 30 weeks, most twin pregnancies with PPROM delivered within 2 days. Infection appears to be a consequence rather than a cause of PPROM in most cases.

  16. Two wide-angle imaging neutral-atom spectrometers (TWINS)

    International Nuclear Information System (INIS)

    McComas, D.J.; Blake, B.; Burch, J.

    1998-01-01

    Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) is a revolutionary new mission designed to stereoscopically image the magnetosphere in charge exchange neutral atoms for the first time. The authors propose to fly two identical TWINS instruments as a mission of opportunity on two widely-spaced high-altitude, high-inclination US Government spacecraft. Because the spacecraft are funded independently, TWINS can provide a vast quantity of high priority science observations (as identified in an ongoing new missions concept study and the Sun-Earth Connections Roadmap) at a small fraction of the cost of a dedicated mission. Because stereo observations of the near-Earth space environs will provide a particularly graphic means for visualizing the magnetosphere in action, and because of the dedication and commitment of the investigator team to the principles of carrying space science to the broader audience, TWINS will also be an outstanding tool for public education and outreach

  17. Adult glucose metabolism in extremely birthweight-discordant monozygotic twins

    DEFF Research Database (Denmark)

    Frost, M; Petersen, I; Brixen, K

    2012-01-01

    Low birthweight (BW) is associated with increased risk of type 2 diabetes. We compared glucose metabolism in adult BW-discordant monozygotic (MZ) twins, thereby controlling for genetic factors and rearing environment....

  18. Expanding electricity capacity in Thailand to meet the twin challenges of supply security and environmental protection

    International Nuclear Information System (INIS)

    Nakawiro, Thanawat; Bhattacharyya, Subhes C.; Limmeechokchai, Bundit

    2008-01-01

    Rapid growth in electricity demand in Thailand is a major challenge for electric utilities trying to ensure adequate supply. Continued reliance on natural gas for power supply makes the supply mix non-diversified and exposes the country to supply risks while a diversification to other fossil fuels imposes additional environmental burdens. To find an acceptable solution to this twin challenge, this paper assesses four scenarios of electricity capacity expansion planning for Thailand for the period between 2011 and 2025 under two different assumptions of fuel prices to reflect the case of international high oil price affecting cost of fuels for power generation in Thailand. It is found that the lowest environmental emissions are obtained from the scenario where power generation is highly dominated by natural gas. In contrast, the least cost electricity generation is achieved from the case if nuclear power plant is added into the Thai power system. Reliance on natural gas for power generation increases the spending on gas purchase as a share of the gross domestic product (GDP) - between 2.38% and 3.61% of (GDP). In addition, fuel import dependence, particularly for natural gas and coal, increases exposing the country to possible price volatility. (author)

  19. Birth weight, sex, and celiac disease: a nationwide twin study

    Directory of Open Access Journals (Sweden)

    Kuja-Halkola R

    2017-11-01

    Full Text Available Ralf Kuja-Halkola,1 Benjamin Lebwohl,1,2 Jonas Halfvarson,3 Louise Emilsson,4–6 Patrik K Magnusson,1 Jonas F Ludvigsson1,2,7,8 1Department Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; 2Department of Medicine, Celiac Disease Center, Columbia University Medical Center, Columbia University, New York, NY, USA; 3Department of Gastroenterology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; 4Department of Health Management and Health Economy, Institute of Health and Society, University of Oslo, Oslo, Norway; 5Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; 6Centre for Clinical Research, Vårdcentralen Värmlands Nysäter, County Council of Värmland, Värmland, 7Department of Pediatrics, Örebro University Hospital, Örebro, Sweden; 8Division of Epidemiology and Public Health, School of Medicine, City Hospital, University of Nottingham, Nottingham, UK Objective: Earlier research suggests that birth weight may be associated with celiac disease (CD, but the direction of association has been unclear potentially due to confounding effect from genetic and intrafamilial factors. Through within-twin analyses, we aimed to minimize confounding effects such as twins that share genetic and early environmental exposures.Materials and methods: Using the Swedish Twin Registry, we examined the birth weight of 146,830 twins according to the CD status. CD was defined as having villous atrophy according to a small intestinal biopsy reports.Results: The prevalence of diagnosed CD was 0.5% (n=669, and we included 407 discordant pairs of CD–non-CD twins. Comparing the 669 CD patients with non-CD twins, the association between birth weight and future CD was not statistically significant (odds ratio [OR] per 1000 g increase in birth weight: 1.16; 95% confidence interval [CI]=0.97–1.38. In males, the association was positive and statistically significant (OR=1.50; 95% CI

  20. Trust and the Welfare State: The Twin Peaks Curve

    OpenAIRE

    Yann Algan; Pierre Cahuc; Marc Sangnier

    2014-01-01

    We show the existence of a twin peaks relation between trust and the size of the welfare state that stems from two opposing forces. Uncivic people support large welfare states because they expect to benefit from them without bearing their costs. But civic individuals support generous benefits and high taxes only when they are surrounded by trustworthy individuals. We provide empirical evidence for these behaviors and this twin peaks relation in the OECD countries.

  1. Outcomes after physical examination-indicated cerclage in twin gestations.

    Science.gov (United States)

    Miller, Emily S; Rajan, Priya V; Grobman, William A

    2014-07-01

    To compare outcomes of physical examination-indicated cerclage in women with twin gestations to those with singleton gestations and to identify whether risk factors for extremely preterm birth (before 28 weeks) differ between these 2 groups. This is a single institution retrospective cohort study of women who underwent a physical examination-indicated cerclage between Jan. 1, 1980, and Aug. 15, 2012. Differences in characteristics and outcomes were compared between women with twin and singleton gestations. A multivariable analysis was performed to examine whether twin gestation was independently associated with delivery before 28 weeks and whether any effect modification was present between risk factors for preterm birth and the presence of a twin gestation. Of the 442 women who underwent a cerclage during the period of study, 104 (23.5%) had twins. Mean gestational age and digital cervical length at placement did not differ by plurality. Although twins were more likely to deliver at a slightly earlier median gestation than singletons (31.9 weeks; interquartile range, 24.9-35.1 vs 32.7 weeks; interquartile range, 24.6-38.3; P = .015), the frequency of delivery before 28 weeks did not differ between these 2 groups (33.7% vs 35.8%, P = .69). Greater cervical dilation and prolapsing membranes were identified as risk factors for birth digital cervical length twin gestations. Women with a twin pregnancy who received a physical examination-indicated cerclage had similar risk factors for extreme preterm birth and may experience similar obstetric outcomes as women with singleton gestations. Copyright © 2014 Mosby, Inc. All rights reserved.

  2. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    OpenAIRE

    Tuegel, Eric J.; Ingraffea, Anthony R.; Eason, Thomas G.; Spottswood, S. Michael

    2011-01-01

    Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the lif...

  3. Hard-sphere displacive model of extension twinning in magnesium

    OpenAIRE

    Cayron, Cyril

    2017-01-01

    A crystallographic displacive model is proposed for the extension twins in magnesium. The atomic displacements are established, and the homogeneous lattice distortion is analytically expressed as a continuous angular-distortive matrix that becomes a shear when the distortion is complete. The calculations prove that a volume change of 3% occurs for the intermediate states. The twinning plane, even if untilted and restored when the distortion is complete, is not fully invariant during the trans...

  4. There are two twin shadows, but einstein is one

    Directory of Open Access Journals (Sweden)

    Popović Marko E.

    2012-01-01

    Full Text Available 2011 is the international year of chemistry, and it is exactly 100 years past after the P. Langevin promotion of “twin paradox” problem. The hundred year old problem still demands its solution. Twin paradox, established by a physicist, has been representing a nightmare for philosophers, physicists, chemists, and biologists until these days. After a hundred years, it is time to try to close this page in long history of misunderstanding of the special relativity. This analysis has three main assumptions. First, biological systems are a part of physical world and therefore they behave in accordance to the physical laws according to Schrödinger. Second, according to Von Bertalanffy the biological systems are open thermodynamic systems. Because of that the approach of non-equilibrium thermodynamics was used for analyzing the twin paradox. Third, rise of entropy is according to Hyflick strongly connected with aging. Entropy can be taken as a measure of cell age or even human age according to Silva et al. and Gladyshev. So entropy invariance strongly suggests that both twins should be the same age, so there is a potential problem for twin paradox with the second law. The only possible influence of relativity on the chemical reaction rate is time dilatation. However time flow does not cause the aging process, so time dilatation cannot have any influence on it. So, after detailed analysis, it is concluded that there is no twin paradox in reality. Both twins will be exactly in same thermodynamic state and bio-logical age. The traveler twin will notice time dilatation, but this relativistic effect has no influence on the aging process.

  5. Development of customized fetal growth charts in twins.

    Science.gov (United States)

    Ghi, Tullio; Prefumo, Federico; Fichera, Anna; Lanna, Mariano; Periti, Enrico; Persico, Nicola; Viora, Elsa; Rizzo, Giuseppe

    2017-05-01

    Twin gestations are at significantly higher risk of fetal growth restriction in comparison with singletons. Using fetal biometric charts customized for obstetrical and parental characteristics may facilitate an accurate assessment of fetal growth. The objective of the study was to construct reference charts for the gestation of fetal biometric parameters stratified by chorionicity and customized for obstetrical and parental characteristics. Fetal biometric measurements obtained from serial ultrasound examinations in uncomplicated twin pregnancies delivering after 36 weeks of gestation were collected by 19 Italian fetal medicine units under the auspices of the Società Italiana di Ecografia Ostetrica e Ginecologica. The measurements acquired in each fetus at each examination included biparietal diameter, head circumference, abdominal circumference, and femur length. Multilevel linear regression models were used to adjust for the serial ultrasonographic measurements obtained and the clustering of each fetus in twin pregnancy. The impact of maternal and paternal characteristics (height, weight, ethnicity), parity, fetal sex, and mode of conception was also considered. Models for each parameter were stratified by fetal chorionicity and compared with our previously constructed growth curves for singletons. The data set included 1781 twin pregnancies (dichorionic, n = 1289; monochorionic diamniotic, n = 492) with 8923 ultrasonographic examinations with a median of 5 (range, 2-8) observations per pregnancy in dichorionic and 6 in (range, 2-11) monochorionic pregnancies. Growth curves of twin pregnancies differed from those of singletons, and differences were more marked in monochorionic twins and during the third trimester. A significant influence of parental characteristics was found. Curves of fetal biometric measurements in twins are influenced by parental characteristics. There is a reduction in the growth rate during the third trimester. The reference limits for

  6. The first large population based twin study of coeliac disease

    Science.gov (United States)

    Greco, L; Romino, R; Coto, I; Di Cosmo, N; Percopo, S; Maglio, M; Paparo, F; Gasperi, V; Limongelli, M G; Cotichini, R; D'Agate, C; Tinto, N; Sacchetti, L; Tosi, R; Stazi, M A

    2002-01-01

    Background and aims: The genetic load in coeliac disease has hitherto been inferred from case series or anecdotally referred twin pairs. We have evaluated the genetic component in coeliac disease by estimating the concordance rate for the disease among twin pairs in a large population based study. Methods: The Italian Twin Registry was matched with the membership lists of a patient support group. Forty seven twin pairs were recruited and screened for antiendomysial (EMA) and antihuman-tissue transglutaminase (anti-tTG) antibodies; zygosity was verified by DNA fingerprinting and twins were typed for HLA class II DRB1 and DQB1 molecules. Results: Concordance rates for coeliac disease differ significantly between monozygotic (MZ) (0.86 probandwise and 0.75 pairwise) and dizygotic (DZ) (0.20 probandwise and 0.11 pairwise) twins. This is the highest concordance so far reported for a multifactorial disease. A logistic regression model, adjusted for age, sex, number of shared HLA haplotypes, and zygosity, showed that genotypes DQA1*0501/DQB1*0201 and DQA1*0301/DQB1*0302 (encoding for heterodimers DQ2 and DQ8, respectively) conferred to the non-index twin a risk of contracting the disease of 3.3 and 1.4, respectively. The risk of being concordant for coeliac disease estimated for the non-index twin of MZ pairs was 17 (95% confidence interval 2.1–134), independent of the DQ at risk genotype. Conclusion: This study provides substantial evidence for a very strong genetic component in coeliac disease, which is only partially due to the HLA region. PMID:11950806

  7. Risk of chronic bronchitis in twin pairs discordant for smoking

    DEFF Research Database (Denmark)

    Meteran, Howraman; Thomsen, Simon Francis; Harmsen, Lotte

    2012-01-01

    It is well known that smoking is a major risk factor for lung disease and respiratory symptoms. We examined the association between smoking and the risk of chronic bronchitis in a large twin sample.......It is well known that smoking is a major risk factor for lung disease and respiratory symptoms. We examined the association between smoking and the risk of chronic bronchitis in a large twin sample....

  8. Delayed Interval Delivery following Early Loss of the Leading Twin

    Directory of Open Access Journals (Sweden)

    P. C. Udealor

    2015-01-01

    Full Text Available This was a case of a nulliparous woman with reduced chance of conception following unilateral salpingectomy and years of infertility. She eventually conceived following ovulation induction resulting in twin pregnancy. She had miscarriage that led to loss of one of the twins at 17 weeks of gestational age. The pregnancy was however continued for 116 days following meticulous management with eventual delivery of a live female baby with good outcome.

  9. Prenatal x-ray exposure and childhood cancer in twins

    International Nuclear Information System (INIS)

    Harvey, E.B.; Boice, J.D. Jr.; Honeyman, M.; Flannery, J.T.

    1985-01-01

    A case-control study was conducted to investigate the relation between prenatal exposure to x-rays and childhood cancer, including leukemia, in over 32,000 twins born in Connecticut from 1930 to 1969. Twins as opposed to single births were chosen for study to reduce the likelihood of medical selection bias, since twins were often exposed to x-rays to diagnose the twin pregnancy or to determine fetal positioning before delivery and not because of medical conditions that may conceivably pre-dispose to cancer. Each of 31 incident cases of cancer, identified by linking the Connecticut twin and tumor registries, was matched with four twin controls according to sex, year of birth, and race. Records of hospitals, radiologists, and private physicians were searched for histories of x-ray exposure and other potentially important risk factors. Documented prenatal x-ray exposures were found for 39 per cent of the cases (12 of 31) and for 26 per cent of the controls (28 of 109). No other pregnancy, delivery, or maternal conditions were associated with cancer risk except low birth weight: 38 per cent of the cases as compared with 25 per cent of the controls weighed under 2.27 kg at birth. When birth weight was adjusted for, twins in whom leukemia or other childhood cancer developed were twice as likely to have been exposed to x-rays in utero as twins who were free of disease (relative risk, 2.4; 95 per cent confidence interval, 1.0 to 5.9). The results, though based on small numbers, provide further evidence that low-dose prenatal irradiation may increase the risk of childhood cancer

  10. Gene expression profiles in Finnish twins with multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Kaprio Jaakko

    2006-02-01

    Full Text Available Abstract Background Since genetic alterations influencing susceptibility to multiple sclerosis (MS, the most common autoimmune demyelinating disease of the central nervous system (CNS, are as yet poorly understood, the purpose of this study was to identify genes responsible for MS by studying monozygotic (MZ twin pairs discordant for MS. Methods In order to identify genes involved in MS development, the gene expression profiles in blood mononuclear cells obtained from eight MZ twin pairs discordant for MS were analyzed by cDNA microarray technology detecting the expression of 8 300 genes. The twins were collected from the Finnish Twin Cohort Study and both affected subjects and their healthy siblings underwent neurological evaluation and cerebral and spinal magnetic resonance imaging. Gene expressions were confirmed by relative quantitative reverse transcription PCR. Results It appeared that 25 genes were at least two-fold up-regulated and 15 genes down-regulated in 25% (2/8 of twins with MS when compared to their healthy siblings. Moreover, 6/25 genes were up-regulated in 40% of MS twins and one gene, interferon alpha-inducible protein (clone IFI-6-16 (G1P3, in 50% of them. The six most constantly expressed genes are (1 G1P3, (2 POU domain, class 3, transcription factor 1, (3 myxovirus resistance 2, (4 lysosomal-associated multispanning membrane protein-5, (5 hemoglobin alpha 2 and (6 hemoglobin beta. Conclusion Over two-fold up-regulation of these six genes in almost half of MZ twins with MS suggests their role in MS pathogenesis. Studies using MZ MS twins obtained from genetically homogeneous population offer a unique opportunity to explore the genetic nature of MS.

  11. Antenatal Surveillance in Twin Pregnancies Using the Biophysical Profile.

    Science.gov (United States)

    Booker, Whitney; Fox, Nathan S; Gupta, Simi; Carroll, Rachel; Saltzman, Daniel H; Klauser, Chad K; Rebarber, Andrei

    2015-11-01

    Objectives-The nonstress test is currently the most widely used modality for antenatal surveillance in twin pregnancies, with a quoted false-positive rate of 11%-12%. Our objective was to report our experience with the sonographic portion of the biophysical profile in twin pregnancies as the primary screening modality.Methods-Women with twin pregnancies delivered by a single maternal-fetal medicine practice from 2005 to 2013 were included. We excluded monoamniotic twins. Twin pregnancies began weekly sonography for the biophysical profile starting at 32 to 33 weeks, or earlier if indicated. The nonstress test was performed if the sonographic biophysical profile score was less than 8 of 8. We reviewed biophysical profile scores and outcomes for all patients who delivered at 33 weeks or later to assess the false-positive rate for the biophysical profile, as well as the incidence of intrauterine fetal death (IUFD) after initiation of antenatal surveillance.Results-A total of 539 twin pregnancies were included. The incidence of IUFD per patient was 2 per 539 (0.4%; 95% confidence interval [CI], 0.1%-1.3%), and the incidence of IUFD per fetus was 2 per 1078 (0.19%; 95% CI, 0.05%-0.7%). The overall positive screen rate was 24 per 539 (4.45%; 95% CI, 3.0%-6.5%). The false-positive screen rate, defined as an abnormal biophysical profile that did not diagnose an IUFD or lead to delivery, was 10 per 539 (1.9%; 95% CI, 1.0%-3.4%).Conclusions-In twin pregnancies the use of the sonographic biophysical profile for routine antenatal surveillance has a low false-positive rate, with a very low incidence of IUFD. The sonographic biophysical profile should be considered as a primary mode for antenatal surveillance in twin pregnancies, with a reflex nonstress test for an abnormal score. © 2015 by the American Institute of Ultrasound in Medicine.

  12. Epigenetic signature of birth weight discordance in adult twins

    DEFF Research Database (Denmark)

    Tan, Qihua; Nielsen, Morten Frost Munk; Heijmans, Bastiaan T

    2014-01-01

    between birth weight and adult life health while controlling for not only genetics but also postnatal rearing environment. We performed an epigenome-wide profiling on blood samples from 150 pairs of adult monozygotic twins discordant for birth weight to look for molecular evidence of epigenetic signatures...... profiling did not reveal epigenetic signatures of birth weight discordance although some sites displayed age-dependent intra-pair differential methylation in the extremely discordant twin pairs....

  13. Conjoined twins: twenty years' experience at a reference center in Brazil

    Directory of Open Access Journals (Sweden)

    Ana Cristina Aoun Tannuri

    2013-01-01

    Full Text Available OBJECTIVE: This study reports on the experience of one hospital regarding the surgical aspects, anatomic investigation and outcomes of the management of 21 conjoined twin pairs over the past 20 years. METHODS: All cases of conjoined twins who were treated during this period were reviewed. A careful imaging evaluation was performed to detail the abdominal anatomy (particularly the liver, inferior vena cava, spleen and pancreas, either to identify the number of organs or to evaluate the degree of organ sharing. RESULTS: There were eight sets of ischiopagus twins, seven sets of thoracopagus twins, three sets of omphalopagus twins, two sets of thoraco-omphalo-ischiopagus twins and one set of craniopagus twins. Nine pairs of conjoined twins could not be separated due to the complexity of the organs (mainly the liver and heart that were shared by both twins; these pairs included one set of ischiopagus twins, six sets of thoracopagus twins and one set of thoraco-omphalo-ischiopagus twins. Twelve sets were separated, including seven sets of ischiopagus twins, three sets of omphalopagus twins, one set of thoracopagus twins and one set of craniopagus conjoined twins. The abdominal wall was closed in the majority of patients with the use of mesh instead of the earlier method of using tissue expanders. The surgical survival rate was 66.7%, and one pair of twins who did not undergo separation is currently alive. CONCLUSION: A detailed anatomic study of the twins and surgical planning must precede separation. A well-prepared pediatric surgery team is sufficient to surgically manage conjoined twins.

  14. Haemoglobin discordances in twins: due to differences in timing of cord clamping?

    Science.gov (United States)

    Verbeek, Lianne; Zhao, Depeng P; Middeldorp, Johanna M; Oepkes, Dick; Hooper, Stuart B; Te Pas, Arjan B; Lopriore, Enrico

    2017-07-01

    Our objective was to study the differences in haemoglobin (Hb) at birth in dichorionic (DC) versus monochorionic (MC) twins in relation to birth order and mode of delivery. All consecutive DC twin pregnancies and uncomplicated MC twin pregnancies with two live-born twins delivered at our centre were included in this retrospective cohort study. Hb levels at birth and on day 2 were evaluated in association with birth order and mode of delivery. The occurrence of polycythaemia (venous haematocrit >65%) was also recorded. A total of 300 DC and 290 MC twin pairs were included. In DC and MC twins delivered vaginally, second-born twins had a higher Hb level at birth compared with their co-twin (mean Hb level 16.7 vs 15.9 g/dL (p<0.01) in DC twins and 17.8 vs 16.1 g/dL (p<0.01) in MC twins). In twins delivered through caesarean section, no intertwin differences in Hb levels were detected. Polycythaemia occurred significantly more often in second-born twins compared with first-born twins delivered vaginally: 10 (5%) vs 2 (1%) (p=0.02) in DC twins and 20 (12%) vs 2 (1%) (p<0.01) in MC twins. Second-born DC and MC twins delivered vaginally have higher Hb levels at birth compared with first-born twins. Intertwin Hb differences in MC twins may partly be related to blood transfusion through the vascular anastomoses. Since DC twins do not have anastomoses, other factors may lead to Hb differences, including differences in timing of umbilical cord clamping. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  15. The Impact of Subsonic Twin Jets on Airport Noise

    Science.gov (United States)

    Bozak, Richard, F.

    2012-01-01

    Subsonic and supersonic aircraft concepts proposed through NASA s Fundamental Aeronautics Program have multiple engines mounted near one another. Engine configurations with multiple jets introduce an asymmetry to the azimuthal directivity of the jet noise. Current system noise predictions add the jet noise from each jet incoherently, therefore, twin jets are estimated by adding 3 EPNdB to the far-field noise radiated from a single jet. Twin jet effects have the ability to increase or decrease the radiated noise to different azimuthal observation locations. Experiments have shown that twin jet effects are reduced with forward flight and increasing spacings. The current experiment investigates the impact of spacing, and flight effects on airport noise for twin jets. Estimating the jet noise radiated from twin jets as that of a single jet plus 3 EPNdB may be sufficient for horizontal twin jets with an s/d of 4.4 and 5.5, where s is the center-to-center spacing and d is the jet diameter. However, up to a 3 EPNdB error could be present for jet spacings with an s/d of 2.6 and 3.2.

  16. A twin-case study of developmental number sense impairment.

    Science.gov (United States)

    Davidse, Neeltje J; de Jong, Maria T; Shaul, Shelley; Bus, Adriana G

    2014-01-01

    The current study reports on 9-year-old monozygotic twin girls who fail to make any progress in learning basic mathematics in primary education. We tested the hypothesis that the twins' core maths problems were deficits in number sense that manifested as impairments in approximate and small number systems, resulting in impairment in nonsymbolic as well as in symbolic processing. While age-matched controls (eight typically developing girls) scored highly, the twins scored at chance on all number sense tasks. More specifically, on a nonsymbolic comparison task, even in the simplest ratio condition of 1:2, and on a subitizing task including only numbers under 4, the twins performed at chance and significantly below the same age control group. Responsiveness to an intervention promoting number sense is discussed. As differences between verbal and performance IQ suggest, there seems to be a high degree of specificity in the twins' developmental number sense delays. The concomitant impairments for visual-spatial processing and working memory in the twins might explain the failure to develop number sense.

  17. Heritability of apnea of prematurity: a retrospective twin study.

    Science.gov (United States)

    Bloch-Salisbury, Elisabeth; Hall, Mei Hua; Sharma, Priya; Boyd, Theonia; Bednarek, Francis; Paydarfar, David

    2010-10-01

    Apnea of prematurity (AOP) is a disturbance in respiratory rhythm defined by idiopathic pauses in breathing that reduce blood oxygen levels and/or heart rate. It is a major clinical problem among preterm infants. The primary goal of this study was to estimate the genetic susceptibility to AOP in a cohort of preterm twins. A secondary aim was to identify risk factors associated with AOP in this cohort. A single-center, retrospective study (2000-2008) was performed by using data from 317 premature twin pairs (premature twins were assessed by using mixed-effects logistic regression. The heritability of AOP was 87% (95% confidence interval [CI]: 0.64-0.97) among same-gender twins. A gender-dependent model revealed that genetic factors accounted for 99% of the variance in male twins (95% CI: 0.89-1.00) and 78% of the variance in female twins (95% CI: 0.49-0.94). Significant risk factors for AOP were low gestational age (P<.001), cesarean delivery (P=.017), and conception through assisted reproductive technologies (P=.008). These findings suggest that AOP has an important genetic basis underlying this developmental-related disorder of respiratory control. Future genomic studies may provide information on pathophysiological mechanisms that underlie AOP.

  18. Heritability of psoriasis in a large twin sample.

    Science.gov (United States)

    Lønnberg, A S; Skov, L; Skytthe, A; Kyvik, K O; Pedersen, O B; Thomsen, S F

    2013-08-01

    Previous twin studies have shown greater concordance rates for psoriasis in MZ than in DZ twins, and heritability estimates between 66% and 90%. This supports a genetic influence on psoriasis, but also highlights the fact that genes are not the only explanation for the disease. To study the concordance of psoriasis in a population-based twin sample. Data on psoriasis in 10 725 twin pairs, aged 20-71 years, from the Danish Twin Registry was collected via a questionnaire survey. The concordance and heritability of psoriasis were estimated. In total, 4·1% of the men and 4·2% of the women had a lifetime history of psoriasis. The proband-wise concordance for psoriasis was larger in monozygotic than in dizygotic twins, 0·33 vs. 0·17. Genetic factors explained 68% (60-75%) of the variation in the susceptibility to psoriasis, whereas the rest of the variation was explained by nonshared environmental factors. The results confirm that psoriasis is a complex multifactorial disease controlled by both exogenous and endogenous factors. © 2013 The Authors BJD © 2013 British Association of Dermatologists.

  19. Microplastic processes developed in pure Ag with mesoscale annealing twins

    Energy Technology Data Exchange (ETDEWEB)

    Al-Fadhalah, Khaled Jabr Hasan [Mechanical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait)], E-mail: fadhalah@kuc01.kuniv.edu.kw; Li, Chun-Ming [Alcan Rolled Products-Ravenswood, LLC. P.O. Box 68, Century Road, Ravenswood, WV 26164 (United States)], E-mail: chun-ming.li@alcan.com; Beaudoin, A.J. [Department of Mechanical Science and Engineering, University of Illinois, 1206 West Green Street, Urbana, IL 61801 (United States)], E-mail: abeaudoi@uiuc.edu; Korzekwa, D.A. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Robertson, I.M. [Department of Materials Science and Engineering, University of Illinois, 1304 W. Green Street, Urbana, IL 61801 (United States)], E-mail: ianr@uiuc.edu

    2008-11-15

    The impact of annealing twin boundaries with a high residual defect content on the mechanical response of polycrystalline fine- and coarse-grained (2 and 20 {mu}m) silver was investigated through transmission electron microscopy and modeling. Besides an increase in the yield strength, the fine-grained material exhibited an inflection in the stress-strain curve after initial yield. Static and dynamic TEM studies revealed that the annealing twin boundaries acted as sources of perfect dislocations, partial dislocations and deformation twins; as barriers to the propagation of these dislocations; and as annihilation sites for dislocations. With increasing strain and as the twin boundaries were penetrated by dislocations, they contributed less to the overall mechanical properties. Based on these observations, equations for the evolution of mobile and forest dislocation densities are posed, depicting boundary sources and dislocation-dislocation interactions, respectively. The deformation response is modeled by computing the aggregate response of matrix-twin composite grains in the viscoplastic self-consistent scheme, which permits consideration of compatibility and equilibrium requirements across the twin boundaries. This work highlights the significant role boundaries play in generating the dislocations that control the macroscopic mechanical response.

  20. Nephrolithiasis in identical twins: the impact of nature vs nurture.

    Science.gov (United States)

    Haleblian, George E; Cantor, David A; Sur, Roger L; Assimos, Dean G; Preminger, Glenn M

    2007-09-01

    To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

  1. Prenatal diagnosis of pygopagus tetrapus parasitic twin: case report

    Directory of Open Access Journals (Sweden)

    Ceylan Yavuz

    2004-07-01

    Full Text Available Abstract Background Asymmetric and parasitic conjoined twins are rarer anomalies of monochorionic monoamniotic twins, consisting of an incomplete twin attached to the fully developed body of the co-twin. Case presentation A 30-year-old multigravid woman referred to maternal fetal unit due to polyhydramnios at 28th week of gestation. Sonographic examination revealed a single fetus and polyhydramnios with amniotic fluid index 30 cm. The fetus had normal apparent single head, spine, thorax, abdomen, two upper and two lower limbs, and two relatively well developed rudimentary parasitic lower limbs at sacral region. Lower limbs of the autosite were moving freelly but no movement was detected at the parasite. The parasite contained irregular lower limbs and left foot with three toes. Short and deformed long bones were also present in the parasitic limbs. A Cesarean section was performed at 38th week of gestation and a live female infant weighing 3600 g was delivered. The parasitic lower limbs were totally excised. Post-operative period was uneventful and the newborn was discharged as healthy. Post-natal follow-up was normal at nine-month-old. Conclusion Pygopagus tetrapus parasitic twin is a rare form of conjoined twins and in utero diagnosis with ultrasound assists in prenatal management and counselling with parents.

  2. On the Observation and Simulation of Solar Coronal Twin Jets

    Science.gov (United States)

    Liu, Jiajia; Fang, Fang; Wang, Yuming; McIntosh, Scott W.; Fan, Yuhong; Zhang, Quanhao

    2016-02-01

    We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jets form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.

  3. Microplastic processes developed in pure Ag with mesoscale annealing twins

    International Nuclear Information System (INIS)

    Al-Fadhalah, Khaled Jabr Hasan; Li, Chun-Ming; Beaudoin, A.J.; Korzekwa, D.A.; Robertson, I.M.

    2008-01-01

    The impact of annealing twin boundaries with a high residual defect content on the mechanical response of polycrystalline fine- and coarse-grained (2 and 20 μm) silver was investigated through transmission electron microscopy and modeling. Besides an increase in the yield strength, the fine-grained material exhibited an inflection in the stress-strain curve after initial yield. Static and dynamic TEM studies revealed that the annealing twin boundaries acted as sources of perfect dislocations, partial dislocations and deformation twins; as barriers to the propagation of these dislocations; and as annihilation sites for dislocations. With increasing strain and as the twin boundaries were penetrated by dislocations, they contributed less to the overall mechanical properties. Based on these observations, equations for the evolution of mobile and forest dislocation densities are posed, depicting boundary sources and dislocation-dislocation interactions, respectively. The deformation response is modeled by computing the aggregate response of matrix-twin composite grains in the viscoplastic self-consistent scheme, which permits consideration of compatibility and equilibrium requirements across the twin boundaries. This work highlights the significant role boundaries play in generating the dislocations that control the macroscopic mechanical response

  4. [Premature twins: clinic comparison, reproductive assisted techniques versus spontaneous conception].

    Science.gov (United States)

    Noriega-Alvarez, Roxana; Iglesias-Leboreiro, José; Bernardez-Zapata, Isabel

    2014-01-01

    Twin pregnancies occur one out of every 800. Due to the increase in maternal age and infertility, the use of assisted reproductive technology (ART) has risen. Thirty five percent of pregnancies solved using ART are twin pregnancies. A RT consists of infertility treatments in which oocytes and sperm are manipulated. The objective of this study was to compare the clinical behavior of premature twins born through ART versus those born after spontaneous conception (SC). Retrolective cohort study. The data was obtained from the records of preterm twins born between August 2010 and August 2013. Preterm twins were categorized in two groups: the ones conceived using ART versus those conceived through SC. Demographic characteristics and neonatal outcomes were compared. The total was of 398 patients: 208 conceived in consequence of ART and 190 through SC. The primary outcome and neonatal morbidities showed no significant difference, only the incidence of necrotizing enterocolitis and the use of parenteral nutrition showed significant difference. The length of hospital stay between groups was similar. In our population of preterm twins, the mode of conception had no detectable effect on mortality or short term morbidities.

  5. Education in Twins and Their Parents Across Birth Cohorts Over 100 years : An Individual-Level Pooled Analysis of 42-Twin Cohorts

    NARCIS (Netherlands)

    Silventoinen, Karri; Jelenkovic, Aline; Latvala, Antti; Sund, Reijo; Yokoyama, Yoshie; Ullemar, Vilhelmina; Almqvist, Catarina; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Kandler, Christian; Honda, Chika; Inui, Fujio; Iwatani, Yoshinori; Watanabe, Mikio; Rebato, Esther; Stazi, Maria A; Fagnani, Corrado; Brescianini, Sonia; Hur, Yoon-Mi; Jeong, Hoe-Uk; Cutler, Tessa L; Hopper, John L; Busjahn, Andreas; Saudino, Kimberly J; Ji, Fuling; Ning, Feng; Pang, Zengchang; Rose, Richard J.; Koskenvuo, Markku; Heikkilä, Kauko; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Sung, Joohon; Kim, Jina; Lee, Jooyeon; Lee, Sooji; Nelson, Tracy L; Whitfield, Keith E; Tan, Qihua; Zhang, Dongfeng; Llewellyn, Clare H; Fisher, Abigail; Burt, S Alexandra; Klump, Kelly L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Medland, Sarah E; Martin, Nicholas G; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Dahl Aslan, Anna K; Corley, Robin P; Huibregtse, Brooke M; Öncel, Sevgi Y; Aliev, Fazil; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Catharina E M; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Rasmussen, Finn; Tynelius, Per; Baker, Laura A; Tuvblad, Catherine; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Gatz, Margaret; Butler, David A; Lichtenstein, Paul; Goldberg, Jack H; Harden, K Paige; Tucker-Drob, Elliot M; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Franz, Carol E; Kremen, William S; Lyons, Michael J; Maia, José A; Freitas, Duarte L; Turkheimer, Eric; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko

    2017-01-01

    Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ

  6. Identification of promising Twin Hub networks : Report of Work Package 1 of the Intermodal rail freight Twin hub Network Northwest Europe - project (final report)

    NARCIS (Netherlands)

    Kreutzberger, E.D.; Konings, J.W.; Meijer, S.; Witteveen, C.; Meijers, B.M.; Pekin, E.; Macharis, C.; Kiel, J.; Kawabata, Y.; Vos, W.

    2014-01-01

    This report is the first deliverable of the project Intermodal Rail Freight Twin Hub Network Northwest Europe. We call its subject Twin hub network and the organisational entity to carry out the actions the Twin hub project. The project is funded by INTERREG NWE (programme IVb). Its work started in

  7. Evolution of Matrix-Twin Interfaces of (1 0 -1 2) Twin in Magnesium

    Czech Academy of Sciences Publication Activity Database

    Ostapovets, Andriy; Serra, A.

    2015-01-01

    Roč. 128, č. 4 (2015), s. 661-663 ISSN 0587-4246. [ISPMA13 - International Symposium on Physics of Materials /13./. Praha, 31.08.2014-04.09.2014] R&D Projects: GA MŠk(CZ) EE2.3.30.0063; GA MŠk(CZ) ED1.1.00/02.0068 Grant - others:Spanish Secretariat of Research , Development and Innovation (ES) FIS2012-39433-C02-02 Institutional support: RVO:68081723 Keywords : twinning * magnesium * computer simuations Subject RIV: JG - Metallurgy Impact factor: 0.525, year: 2015

  8. Lander petal & Twin Peaks - 3D

    Science.gov (United States)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes. A lander petal, airbag, and the rear ramp are at the lower area of the image.The image was taken by the Imager for Mars Pathfinder (IMP) after its deployment on Sol 3. Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  9. North Twin Peak in super resolution

    Science.gov (United States)

    1997-01-01

    This pair of images shows the result of taking a sequence of 25 identical exposures from the Imager for Mars Pathfinder (IMP) of the northern Twin Peak, with small camera motions, and processing them with the Super-Resolution algorithm developed at NASA's Ames Research Center.The upper image is a representative input image, scaled up by a factor of five, with the pixel edges smoothed out for a fair comparison. The lower image allows significantly finer detail to be resolved.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.The super-resolution research was conducted by Peter Cheeseman, Bob Kanefsky, Robin Hanson, and John Stutz of NASA's Ames Research Center, Mountain View, CA. More information on this technology is available on the Ames Super Resolution home page athttp://ic-www.arc.nasa.gov/ic/projects/bayes-group/ group/super-res/

  10. [Spontaneous hepatic hematoma in twin pregnancy].

    Science.gov (United States)

    Quesnel, Carlos; Weber, Alejandro; Mendoza, Dalila; Garteiz, Denzil

    2012-02-01

    The hepatic hematoma or rupture appear in 1 of every 100,000 pregnancies. The most common causes of hepatic hematoma in pregnancy are severe preeclampsia and HELLP syndrome; some predisposing factors are seizures, vomiting, labor, preexistent hepatic disease and trauma. A 33 year old primigravid with a normal 33 week twin pregnancy presented abdominal pain and hypovolemic shock due to spontaneous subcapsular hepatic hematoma; laparoscopy was performed to evaluate the possibility of rupture, which was not found, later emergency cesarean section was carried out followed by hepatic hematoma drainage and abdominal packaging by laparoscopy. After surgery the flow through drainage was too high additionally hemodynamic instability and consumption coagulopathy. Abdominal panangiography was performed without identifying bleeding areas. Intesive care was given to the patient evolving satisfactorily, was discharged 19 days after the event. Seven months later she had laparoscopic cholecystectomy due to acute litiasic colecistitis. We found 5 cases in literatura about hepatic hematoma during pregnancy no related to hypertensive disorders of pregnancy; these were related to hepatoma, amebian hepatic abscess, falciform cell anemia, cocaine consumption and molar pregnancy. Hepatics hematomas have high morbidity and mortality so is significant early diagnosis and multidisciplinary approach.

  11. Prediction of twin-arginine signal peptides

    Directory of Open Access Journals (Sweden)

    Widdick David

    2005-07-01

    Full Text Available Abstract Background Proteins carrying twin-arginine (Tat signal peptides are exported into the periplasmic compartment or extracellular environment independently of the classical Sec-dependent translocation pathway. To complement other methods for classical signal peptide prediction we here present a publicly available method, TatP, for prediction of bacterial Tat signal peptides. Results We have retrieved sequence data for Tat substrates in order to train a computational method for discrimination of Sec and Tat signal peptides. The TatP method is able to positively classify 91% of 35 known Tat signal peptides and 84% of the annotated cleavage sites of these Tat signal peptides were correctly predicted. This method generates far less false positive predictions on various datasets than using simple pattern matching. Moreover, on the same datasets TatP generates less false positive predictions than a complementary rule based prediction method. Conclusion The method developed here is able to discriminate Tat signal peptides from cytoplasmic proteins carrying a similar motif, as well as from Sec signal peptides, with high accuracy. The method allows filtering of input sequences based on Perl syntax regular expressions, whereas hydrophobicity discrimination of Tat- and Sec-signal peptides is carried out by an artificial neural network. A potential cleavage site of the predicted Tat signal peptide is also reported. The TatP prediction server is available as a public web server at http://www.cbs.dtu.dk/services/TatP/.

  12. LIGO Education and Outreach at Twin Observatories

    Science.gov (United States)

    Thacker, John

    2007-04-01

    LIGO has twin Gravitational Wave observatories in Hanford, WA and Livingston, LA. Both sites have active outreach programs but each has a different emphasis and methodology. We will briefly describe the nature of these outreach programs. We will then focus attention on the Livingston facility since its outreach program is centered on a new 9000 sq.ft. Science Education Center. We will describe the facility and its exhibits then discuss the structure of the outreach program at the Center. The objectives of the Center are to: communicate LIGO-related science concepts to the public; strengthen skills and abilities of in-service and pre-service teachers and enhance the science and mathematics skills of a broad spectrum of students in Louisiana and the surrounding region. By partnering with a museum (The Exploratorium), a university (Southern University at Baton Rouge) and a state education agency for education reform, LA GEAR UP, we have been able to quickly open up opportunities. Benefiting from our fine collaborators, we've been able to create positive impact in the local science education community in a relatively brief time span.

  13. Twin screw wet granulation: Binder delivery.

    Science.gov (United States)

    Saleh, Mohammed F; Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2015-06-20

    The effects of three ways of binder delivery into the twin screw granulator (TSG) on the residence time, torque, properties of granules (size, shape, strength) and binder distribution were studied. The binder distribution was visualised through the transparent barrel using high speed imaging as well as quantified using offline technique. Furthermore, the effect of binder delivery and the change of screw configuration (conveying elements only and conveying elements with kneading elements) on the surface velocity of granules across the screw channel were investigated using particle image velocimetry (PIV). The binder was delivered in three ways; all solid binder incorporated with powder mixture, 50% of solid binder mixed with powder mixture and 50% mixed with water, all the solid binder dissolved in water. Incorporation of all solid binder with powder mixture resulted in the relatively longer residence time and higher torque, narrower granule size distribution, more spherical granules, weaker big-sized granules, stronger small-sized granules and better binder distribution compared to that in other two ways. The surface velocity of granules showed variation from one screw to another as a result of uneven liquid distribution as well as shown a reduction while introducing the kneading elements into the screw configuration. Copyright © 2015. Published by Elsevier B.V.

  14. Neurodevelopmental outcome at 2 years in twin-twin transfusion syndrome survivors randomized for the Solomon trial.

    Science.gov (United States)

    van Klink, Jeanine M M; Slaghekke, Femke; Balestriero, Marina A; Scelsa, Barbara; Introvini, Paola; Rustico, Mariangela; Faiola, Stefano; Rijken, Monique; Koopman, Hendrik M; Middeldorp, Johanna M; Oepkes, Dick; Lopriore, Enrico

    2016-01-01

    The preferred treatment for twin-twin transfusion syndrome is fetoscopic laser coagulation of inter-twin vascular anastomoses on the monochorionic placenta. Severe postoperative complications can occur when inter-twin vascular anastomoses remain patent including twin-anemia polycythemia sequence or recurrent twin-twin transfusion syndrome. To minimize the occurrence of residual anastomoses, a modified laser surgery technique, the Solomon technique, was developed in which the entire vascular equator is coagulated. In the Solomon randomized controlled trial (NTR1245), the Solomon technique was associated with a significant reduction in twin-anemia polycythemia sequence and recurrence of twin-twin transfusion syndrome when compared with the standard laser surgery technique. Although a significant improvement in perinatal outcome was shown after the Solomon technique, the clinical importance should also be ascertained with long-term follow-up evaluation of the surviving children. The purpose of this study was to compare the long-term neurodevelopmental outcome in surviving children with twin-twin transfusion syndrome who were included in the Solomon randomized trial and treated with either the Solomon technique or standard laser surgery technique. Routine standardized follow-up evaluation in survivors, at least 2 years after the estimated date of delivery, was performed at 2 of the 5 centers that participated in the Solomon trial: Buzzi Hospital Milan (Italy) and Leiden University Medical Center (The Netherlands). The primary outcome of this follow-up study was survival without long-term neurodevelopmental impairment at age 2 years. Neurodevelopmental impairment was defined as cerebral palsy, cognitive and/or motor development score of blindness, or deafness. Cognitive and motor development was evaluated with the use of Bayley-III. All analyses per fetus, neonate, or child were conducted with the generalized estimated equation module to account for the effect that

  15. A study of the occurrence of monochorionic and monozygotic twinning in the pig

    DEFF Research Database (Denmark)

    Bjerre, Ditte; Thorup, F.; Jørgensen, Claus Bøttcher

    2009-01-01

    Summary In humans as well as in most farm animals, monozygotic twins have been described. Nevertheless, only a few reports of twinning in the pig have been published. It has been suggested that monozygotic twins are formed during the first 14 days of pregnancy. This monozygotic twin study include...... was found among these embryos. In the latter group, three monozygotic twin pairs were identified. Thus, it can be concluded that although the occurrence of monozygotic twins in pigs is a sporadic event, the fusion of extra-embryonic membranes is relatively common....

  16. Physical activity, fitness, glucose homeostasis, and brain morphology in twins.

    Science.gov (United States)

    Rottensteiner, Mirva; Leskinen, Tuija; Niskanen, Eini; Aaltonen, Sari; Mutikainen, Sara; Wikgren, Jan; Heikkilä, Kauko; Kovanen, Vuokko; Kainulainen, Heikki; Kaprio, Jaakko; Tarkka, Ina M; Kujala, Urho M

    2015-03-01

    The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

  17. Sleep Duration, Mortality, and Heredity-A Prospective Twin Study.

    Science.gov (United States)

    Åkerstedt, Torbjörn; Narusyte, Jurgita; Alexanderson, Kristina; Svedberg, Pia

    2017-10-01

    A number of studies have shown a U-shaped association between sleep duration and mortality. Since sleep duration is partly genetically determined, it seems likely that its association with mortality is also genetically influenced. The purpose of the present study was to investigate the influence on heredity on the association between sleep duration and mortality. We used a cohort of 14267 twins from the Swedish Twin Registry. A Cox proportional hazards regression analysis, adjusted for a number of covariates, confirmed a clear U shape with a hazard ratio (HR) = 1.34 and 95% confidence interval (CI) = 1.15-1.57 for a sleep duration of ≤6.5 hours and HR = 1.18 (CI = 1.07-1.30) for sleep of ≥9.5 hours. Reference value was 7.0 hours. A co-twin analysis of 1942 twins discordant on mortality showed a HR = 2.66 (CI = 1.17-6.04) for long (≥9.5 hours) sleep in monzygotic twins and an HR = 0.66 (CI = 0.20-2.14) for short (sleep. In dizygotic twins, no association was significant. The heritability for mortality was 28% for the whole group, while it was 86% for short sleepers and 42% for long sleepers. Thus, the link with mortality for long sleep appears to be more due to environmental factors than to heredity, while heritability dominates among short sleepers. We found that both long and short sleep were associated with higher total mortality, that the difference in mortality within twin pairs is associated with long sleep, and that short sleep has a higher heritability for mortality, while long sleep is associated with more environmental influences on mortality. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  18. Effect of Amnioreduction on Maternal and Perinatal Outcomes in Patients with Twin - Twin Transfusion Syndrome

    Directory of Open Access Journals (Sweden)

    Tugba Ensari

    2014-12-01

    Full Text Available Aim: To assess the effect of amnioreduction on perinatal outcomes in patients with twin %u2013 twin transfusion syndrome (TTTS. Material and Method: 42 patients with TTTS were enrolled into this study. 14 of 42 patients who underwent amnioreduction formed the study group and 28 of 42 patients who did not undergo amnioreduction formed the control group. Effects of amnioreduction on average week of birth, birth weight, need of neonatal intensive care and perinatal mortality were gathered from medical records retrospectively. P score under 0.05 was accepted as significant. Results: Average week of birth of women who underwent amnioreduction was 28.7 ± 4.1 however it was 31.8 ± 4.9 on control group. Although number of births under 32 weeks is 12 (85.7% and under 28 weeks is 10 (71.4% on patients who underwent amnioreduction, it was 12 (43.1% for under 32 weeks and 9 (32.1% for under 28 weeks in control group (P

  19. [Outcome of triplet pregnancies managed for twin-to-twin transfusion syndrome: A single center experience].

    Science.gov (United States)

    Chalouhi, G E; Quibel, T; Benzina, N; Bernard, J-P; Essaoui, M; Ville, Y

    2016-10-01

    Study the outcomes of triplet pregnancies (GGG) complicated with twin-to-twin transfusion syndrome (TTTS) treated with laser fetoscopy. Retrospective study of interventions, outcomes and perinatal follow-up of GGG treated for TTS. Between 2002 and 2013, 25 GGG complicated by TTTS were seen in our center, 20 dichorionic and 5 monochorionic. The mean gestational age (GA) at diagnosis of TTTS was 19.7 GW (±2.4) with 2, 4, 16 and 1 pregnancies at Quintero's stage I, II, III and V, respectively. They had a fetoscopy at an average GA of 19 GW and 6 days. There were 3 (13.0%) late miscarriages. The average GA at delivery was of 29.6 GW overall (26.3 GW and 31.1 GW in monochorionic and dichorionic pregnancies respectively). The overall fetal survival rate was 57.97% (40% and 66.7% in the group of monochorionic dichorionic pregnancies, respectively). However, neonatal mortality (<28 days) is 17.5%. GGG operated by fetoscopy for TTTS have a survival rate of three, at least 2 and at least 1 fetus of 21.7%, 69.6% and 82.6% respectively. The overall fetal survival rate is 59.97%. There is a tendency for better survival rates in dichorionic GGG compared to monochorionic GGG (P=0.079). Copyright © 2016. Published by Elsevier Masson SAS.

  20. Characterization of a Twin-Entry Radial Turbine under Pulsatile Flow Condition

    Directory of Open Access Journals (Sweden)

    Mahfoudh Cerdoun

    2016-01-01

    Full Text Available In automotive applications radial gas turbines are commonly fitted with a twin-entry volute connected to a divided exhaust manifold, ensuring a better scavenge process owing to less interference between engines’ cylinders. This paper is concerned with the study of the unsteady performances related to the pulsating flows of a twin-entry radial turbine in engine-like conditions and the hysteresis-like behaviour during the pulses period. The results show that the aerodynamic performances deviate noticeably from the steady state and depend mainly on the time shifting between the actual output power and the isentropic power, which is distantly related to the apparent length. The maximum of efficiency and output shaft power are accompanied by low entropy generation through the shroud entry side, and their instantaneous behaviours tend to follow mainly the inlet total pressure curve. As revealed a billow is created by the interaction between the main flow and the infiltrated flow, affecting the flow incidence at rotor entry and producing high losses.

  1. Practical acoustic thermometry with twin-tube and single-tube sensors

    International Nuclear Information System (INIS)

    De Podesta, M.; Sutton, G.; Edwards, G.; Stanger, L.; Preece, H.

    2015-01-01

    Accurate measurement of high temperatures in a nuclear environment presents unique challenges. All secondary techniques inevitably drift because the thermometric materials in thermocouples and resistance sensors are sensitive not just to temperature, but also their own chemical and physical composition. The solution is to use primary methods that rely on fundamental links between measurable physical properties and temperature. In the nuclear field the best known technique is the measurement of Johnson Noise in a resistor (See Paper 80 at this conference). In this paper we describe the measurement of temperature in terms of the speed of sound in a gas confined in a tube - an acoustic waveguide. Acoustic thermometry is the most accurate technique of primary thermometry ever devised with the best uncertainty of measurement below 0.001 C. In contrast, the acoustic technique described in this work has a much larger uncertainty, approximately 1 deg. C. But the cost and ease of use are improved by several orders of magnitude, making implementation eminently practical. We first describe the basic construction and method of operation of thermometers using twin-tubes and single tubes. We then present results using a twin-tube design showing that showing long term stability (i.e. no detectable drift) at 700 deg. C over periods of several weeks. We then outline how the technique may be developed for different nuclear applications. (authors)

  2. Experimental study on p-V indicator diagrams of twin-screw refrigeration compressor with economizer

    International Nuclear Information System (INIS)

    Wu Huagen; Peng Xueyuan; Xing Ziwen; Shu Pengcheng

    2004-01-01

    This paper presents the experimental investigation on the effects of the superfeed pressure together with economizer type on the performance of the twin-screw refrigeration compressor by means of the indicator diagram. With a pressure sensor embedded into the groove at the root of the female rotor on the discharge side, the pressure within the working chamber of a semi-hermetic twin-screw compressor with an economizer is recorded and then transformed into the indicator diagram. The results thus obtained are utilized to investigate the thermodynamic process of the compressor. It is shown that the compressor with an economizer has higher pressure during almost the whole compression process than without an economizer, resulting in the increase in the indicated power. Under different superfeed pressures, the pressure within the compression experiences different changes. This results in an optimal superfeed pressure for maximized compressor efficiency, which can be identified from the calculated compressor efficiency based on the indicator diagrams. It is also found that the pressure has a rapid increase at the beginning of superfeed process, and then a slow rise even a slight drop at the end of superfeed process, which is caused by the dynamic effect during superfeed process. Furthermore, if the superfeed pressure keeps the same, the pressure during compression in the compressor with the heat exchanger economizer is slightly higher than with the flash tank economizer, due to the higher temperature of superfeed refrigerant gas in the former case

  3. Landau spectrum and twin boundaries of bismuth in the extreme quantum limit

    Science.gov (United States)

    Zhu, Zengwei; Fauqué, Benoît; Malone, Liam; Antunes, Arlei Borba; Fuseya, Yuki; Behnia, Kamran

    2012-01-01

    The Landau spectrum of bismuth is complex and includes many angle-dependent lines in the extreme quantum limit. The adequacy of single-particle theory to describe this spectrum in detail has been an open issue. Here, we present a study of angle-resolved Nernst effect in bismuth, which maps the angle-resolved Landau spectrum for the entire solid angle up to 28 T. The experimental map is in good agreement with the results of a theoretical model with parabolic dispersion for holes and an extended Dirac Hamiltonian for electrons. The angular dependence of additional lines in the Landau spectrum allows us to uncover the mystery of their origin. They correspond to the lines expected for the hole Landau levels in a secondary crystal tilted by 108°, the angle between twinned crystals in bismuth. According to our results, the electron reservoirs of the two identical tilted crystals have different chemical potentials, and carriers across the twin boundary have different concentrations. An exceptional feature of this junction is that it separates two electron-hole compensated reservoirs. The link between this edge singularity and the states wrapping a three-dimensional electron gas in the quantum limit emerges as an outstanding open question. PMID:22927380

  4. Two rare complications of twin gestation manifesting as arrest of descent in the second stage of labor

    Directory of Open Access Journals (Sweden)

    P Veena

    2016-01-01

    Full Text Available Two rare complications of twin gestation, namely, conjoined twins and interlocking of twins, manifested as arrest of descent in the second stage of labor. This article reports in detail about how the diagnosis of conjoined twins was missed by ultrasonogram and interlocking of twins unusually occurred in diamniotic twins. The management of these rare conditions is also mentioned to aid readers to act accordingly in rare undiagnosed cases.

  5. Twinship as a resource: zygosity- and gender-based comparison of twins' attitudes toward twinship.

    Science.gov (United States)

    Hegedűs, Rita; Pári, András; Drjenovszky, Zsófia; Kónya, Hanna

    2014-10-01

    Aiming to perform the first sociological survey of Hungarian twins, our main question was whether being a twin has positive consequences on one's life. Adult twins completed our questionnaire at three Hungarian summer twin festivals, in hospitals during medical twin studies, and on some websites online. Data represent 140 twin pairs (mean age: 38.2 ± 14.6 years). We employed some indices for measuring the resource nature of twinship. Three main types of benefits were distinguished: profit of attraction, as 'material capital'; the easier obtainability of cultural goods when twins take part in it, as 'cultural capital'; and positive aspects of an a priori existing dyadic relation, as 'relational capital'. We were interested in the difference among types of twins regarding advantages. We paid special attention to the five groups of twins derived from gender and zygosity (i.e., monozygotic females, monozygotic males, dizygotic females, dizygotic males, opposite-sex pairs). Our analysis showed that Hungarian twins involved in our research basically enjoy their twinship; during their lives they used and still make use of different benefits given by it. In our twin samples, women had more advantages from being a twin than men. Significant differences could be observed on all indicators between monozygotic and dizygotic twins.

  6. Intra-uterine exposure to dual fetal programming sequences among surviving co-twins.

    Science.gov (United States)

    Salihu, Hamisu M; Ibrahimou, Boubakari; Dagne, Getachew A

    2011-01-01

    The dynamics of fetal programming following in utero demise of a co-twin are poorly understood. The authors examined fetal programming using a unique application of the change-point analysis method, and identified two types of fetal programming that occurred when a viable twin sibling died in utero, while the co-twin survived. In one type, the initial twin fetal programming trajectory was maintained while in a subset of surviving co-twins a "switch" from a twin to a singleton fetal program (dual fetal programming exposure) was observed. The results suggest that the timing in utero of conversion from a twin to a singleton programming pattern occurred slightly earlier among opposite-sex than in same-sex surviving co-twins. For the conversion from a twin to a singleton program to happen, the surviving co-twin must have attained a "critical mass" when the twin sibling died. Whereas, for same-sex surviving co-twins the critical mass for conversion was the 80th percentile of gestational-age specific birth weight, opposite-sex surviving co-twins converted at a lower critical mass (70th percentile). These novel findings warrant further study to confirm the new hithertofore unknown phenomenon of dual fetal programming sequence, and to determine the implications in terms of subsequent morbidity or mortality during infancy, childhood and adult life.

  7. Embryo-transfer twinning and performance efficiency in beef production.

    Science.gov (United States)

    Guerra-Martinez, P; Dickerson, G E; Anderson, G B; Green, R D

    1990-12-01

    Effects of twinning on efficiency of beef production were estimated from results of bilateral transfer of two Angus x Hereford (AxH) embryos into each of 241 heifers and 84 cows (H, A, HxA or Holstein x H) over 4 yr. Calves were weaned at 180 d and fed either 220 d in a feedlot (1977) or 170 d on forage and 140 d in a feedlot (1978 to 1980). Effects of parity, twinning and sex of calf were estimated as covariates within year-breed of dam. Pregnancy at 45 to 60 d of gestation was 68% in heifers (H) and 74% in cows (C), with 40% single (S) and 60% twin (T) births. Dystocia was 28% in H vs 10% in C (P less than .05), and tended to be less (P greater than .05) for T than S in H. More placentas were retained (P less than .05) for T than for S in both H (35 vs 12%) and C (24 vs 4%). Twin gestations averaged 3 d shorter and subsequent calving intervals 13 d longer (P less than .05), but total calf mortality was slightly higher (P greater than .05). Abortions were 4% in H only. Twinning females lost maternal weight during late gestation (P less than .05) when crowding limited voluntary feed intake, while fetal requirements were 60% higher (P less than .01). Twins increased milk output 25% (P less than .05), but 11% higher feed intake maintained cow weight during lactation. Twinning reduced birth weight 13% and weaning weight 17% (P less than .05), but 400-d feedlot weight only 9% because of compensating feedlot gain. Twins gained 18% faster than S during postweaning 170-d forage feeding, but 5% slower in feedlot to 8% lighter 490-d weight (P less than .05). Assuming 40% higher veterinary and labor costs for twins, estimated integrated herd costs per unit of age-constant output value would be lower for T than for S production by about 24% for marketing either at weaning or at 400 d.

  8. Outcome reporting across randomised trials and observational studies evaluating treatments for Twin-Twin Transfusion Syndrome: a systematic review.

    Science.gov (United States)

    Perry, Helen; Duffy, James M N; Umadia, Ogochukwu; Khalil, Asma

    2018-04-01

    Twin-Twin Transfusion syndrome is associated with significant mortality and morbidity. Potential treatments require robust evaluation. The aim of this study was to evaluate outcome reporting across observational studies and randomised controlled trials assessing treatments for twin-twin transfusion syndrome (TTTS). Cochrane Central Register of Controlled Trials, EMBASE and Medline were searched from inception to August 2016. Observational studies and randomised controlled trials reporting outcomes following a treatment for TTTS in monochorionic-diamniotic twin pregnancies and monochorionic-triamniotic or dichorionic-triamniotic triplet pregnancies were included. We systematically extracted and categorised outcome reporting. Six randomised trials and 94 observational studies, reporting data from 20,071 maternal participants and 3,199 children, were included. Six different treatments were evaluated. Included studies reported sixty-two different outcomes, including 10 fetal, 28 neonatal, 6 early childhood and 18 maternal outcomes. The outcomes were inconsistently reported across trials. For example, when considering offspring mortality, 31 studies (31%) reported live birth, 31 studies (31%) reported intrauterine death, 49 studies (49%) reported neonatal mortality, and 17 studies (17%) reported perinatal mortality. Four studies (4%) reported respiratory distress syndrome. Only 19 (19%) of studies were designed for long-term follow-up and 11 of these studies (11%) reported cerebral palsy. Most studies evaluating treatments for TTTS, have often neglected to report clinically important outcomes, especially neonatal morbidity outcomes. Most studies are not designed for long-term follow-up. The development of a core outcome set could help standardised outcome collection and reporting in Twin-Twin Transfusion syndrome studies. This article is protected by copyright. All rights reserved.

  9. Atopic diseases in twins born after assisted reproduction.

    Science.gov (United States)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten O; Skytthe, Axel; Backer, Vibeke

    2012-03-01

    We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0.773 respectively) compared with children born after spontaneous conception. Assisted reproduction did not modify the heritability of atopic diseases. This study does not support an association between assisted reproduction and development of atopic diseases. This result must be confirmed in subsequent studies, preferably of singleton populations. © 2011 Blackwell Publishing Ltd.

  10. Coupling Damage-Sensing Particles to the Digitial Twin Concept

    Science.gov (United States)

    Hochhalter, Jacob; Leser, William P.; Newman, John A.; Gupta, Vipul K.; Yamakov, Vesselin; Cornell, Stephen R.; Willard, Scott A.; Heber, Gerd

    2014-01-01

    The research presented herein is a first step toward integrating two emerging structural health management paradigms: digital twin and sensory materials. Digital twin is an emerging life management and certification paradigm whereby models and simulations consist of as-built vehicle state, as-experienced loads and environments, and other vehicle-specific history to enable high-fidelity modeling of individual aerospace vehicles throughout their service lives. The digital twin concept spans many disciplines, and an extensive study on the full domain is out of the scope of this study. Therefore, as it pertains to the digital twin, this research focused on one major concept: modeling specifically the as-manufactured geometry of a component and its microstructure (to the degree possible). The second aspect of this research was to develop the concept of sensory materials such that they can be employed within the digital twin framework. Sensory materials are shape-memory alloys that undergo an audible phase transformation while experiencing sufficient strain. Upon embedding sensory materials with a structural alloy, this audible transformation helps improve the reliability of crack detection especially at the early stages of crack growth. By combining these two early-stage technologies, an automated approach to evidence-based inspection and maintenance of aerospace vehicles is sought.

  11. Monozygotic male twins concordant for Beckwith-Wiedemann syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, M.; McPherson, E.; Sherer, C. [West Penn Hospital, Pittsburgh, PA (United States)]|[Ludwig Institute for Cancer Reseach, LaJolla, CA (United States)] [and others

    1994-09-01

    The Beckwith-Wiedemann syndrome (BWS) is a multiple congenital anomaly syndrome characterized by macrosomia, macro glossia, visceromegaly, characteristic facies, and in some cases omphalocele, hypoglycemia, hemihypertrophy, and risk of embryonal tumors. Most cases occur sporadically in chromosomally normal individuals, but a few BWS patients have anomalies of 11p and others have evidence of microduplications or paternal isodisomy in this region. In some families with autosomal dominant transmission, BWS maps to 11p15.5, but the mechanism of transmission is not fully understood. BWS has been reported in 11 sets of MZ twins, including 10 female pairs (9 discordant and 1 partially concordant) and one male pair concordant for both BWS & dup 15q11.2-q13. We report a pair of premature male MZ twins with macroglossia, postnatal overgrowth, characteristic BWS facies, and mild developmental delay. One twin had hypoglycemia, but neither had omphalocele or hemihypertrophy and serial abdominal ultrasounds have been normal. DNA fingerprinting confirmed monozygosity. Chromosome studies showed a marker 11p14.2 in one twin only, and molecular genetic studies of the 11p15.5 region showed no evidence of duplication or isodisomy in either twin.

  12. Arizona Twin Project: a focus on early resilience.

    Science.gov (United States)

    Lemery-Chalfant, Kathryn; Clifford, Sierra; McDonald, Kristy; O'Brien, T Caitlin; Valiente, Carlos

    2013-02-01

    The Arizona Twin Project is an ongoing longitudinal study designed to elucidate the genetic and environmental influences underlying the development of early competence and resilience to common mental and physical health problems during infancy and childhood. Participants are a sample of 600 twins (25% Hispanic) recruited from birth records in the state of Arizona, United States. Primary caregivers were interviewed on twins' development and early social environments when twins were 12 and 30 months of age. Measures include indices of prenatal and obstetrical risk coded from hospital medical records, as well as primary caregiver-report questionnaires assessing multiple indicators of environmental risk and resilience (e.g., parental warmth and control, family and social support), twins' developmental maturity, temperament, health, behavior problems, and competencies. Preliminary findings highlight the importance of the early environment for infant and toddler health and well-being, both directly and as a moderator of genetic influences. Future directions include a third longitudinal assessment in middle childhood examining daily bidirectional relations between sleep, health behaviors, stress, and mood.

  13. Prenatal screening for and diagnosis of aneuploidy in twin pregnancies.

    Science.gov (United States)

    Audibert, François; Gagnon, Alain

    2011-07-01

    To provide a Canadian consensus document with recommendations on prenatal screening for and diagnosis of fetal aneuploidy (e.g., Down syndrome and trisomy 18) in twin pregnancies. The process of prenatal screening and diagnosis in twin pregnancies is complex. This document reviews the options available to pregnant women and the challenges specific to screening and diagnosis in a twin pregnancy. Clinicians will be better informed about the accuracy of different screening options in twin pregnancies and about techniques of invasive prenatal diagnosis in twins. PubMed and Cochrane Database were searched for relevant English and French language articles published between 1985 and 2010, using appropriate controlled vocabulary and key words (aneuploidy, Down syndrome, trisomy, prenatal screening, genetic health risk, genetic health surveillance, prenatal diagnosis, twin gestation). Results were restricted to systematic reviews, randomized controlled trials, and relevant observational studies. Searches were updated on a regular basis and incorporated in the guideline to August 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The previous Society of Obstetricians and Gynaecologists of Canada guidelines regarding prenatal screening were also reviewed in developing this clinical practice guideline. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). There is a need for specific guidelines for prenatal screening and diagnosis in twins. These guidelines should assist health care providers in the approach to this aspect of prenatal care of women with twin pregnancies. SUMMARY STATEMENTS 1. Fetal nuchal translucency combined with maternal age is an

  14. Estimation of stacking fault and twin energies in transition metals

    International Nuclear Information System (INIS)

    Papon, Anne-Marie

    1979-01-01

    As twins and stacking faults play an important role in the plastic deformation of metals, the objective of this research thesis is, by using an as correct as possible description of band d state density, to assess the internal energy of twins and stacking faults in metals with a CFC, HC or CC crystal structure. If, in transition metals, cohesion mainly results from d electron attraction, other terms intervening in crystal equilibrium must also be taken into account. Thus, the author proposes a decomposition of cohesion energy. The geometry of twins and stacking faults in compact phases is defined, and energy calculations are presented and discussed. Alloying effects are then addressed, as well as a general comparison with available experimental results. After a geometric description of twins and stacking faults in CC structures, their energies are calculated for a Gaussian distribution of state density. For higher order moments, defect energy due to d orbital anisotropy is assessed, and then applied to energy and stability calculations in twins and stacking faults for various relaxed atomic configurations

  15. Matching osteochondritis dissecans lesions in identical twin brothers.

    Science.gov (United States)

    Richie, Lucas B; Sytsma, Mark J

    2013-09-01

    Osteochondritis dissecans is a disorder of unknown etiology that can result in fragmentation of osteochondral surfaces, most commonly of the knee, shoulder, elbow, and ankle. This may lead to sequelae of pain and an inability to participate in desired activities. Multiple theories exist as to the true cause of the disorder, but none have been fully proven. One such proposed etiology is genetic causation. Familial cases of osteochondritis dissecans are rare, yet these cases offer support to growing evidence that may support a genetic link. This article describes osteochondritis dissecans lesions of the femoral trochlea in monozygotic (identical) twins. Both twins presented with similar symptoms 1 year apart. Neither twin had any clear inciting trauma. Magnetic resonance imaging revealed osteochondral lesions in similar positions of the lateral trochlear of the same knee in both brothers. Osteochondral autograft transfer and tibial tubercle anteromedialization were performed on both patients. An identical postoperative protocol was followed, and recovery with full return to sport was comparable for the brothers. To the authors' knowledge, only 1 other case report exists of osteochondritis dissecans lesions in monozygotic twins. Although debate continues regarding the true etiology of this disorder, cases of identical twins presenting with a similar disease process are highly suggestive of a genetic component and may lead to early identification and treatment of these lesions. Continued research in the area of osteochondritis dissecans and its genetic basis is needed to completely understand this disorder. Copyright 2013, SLACK Incorporated.

  16. Twinning of cubic diamond explains reported nanodiamond polymorphs.

    Science.gov (United States)

    Németh, Péter; Garvie, Laurence A J; Buseck, Peter R

    2015-12-16

    The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin ( rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.

  17. Double twist : Can-K's electric submersible twin screw pump is designed to handle the nastiest crudes

    Energy Technology Data Exchange (ETDEWEB)

    Byfield, M.

    2010-12-15

    This article described the Can-K Group of Companies' electric submersible twin screw pump (ESTSP) designed for pumping heavy crudes with high levels of asphaltenes, hydrogen sulphide, wax, and methane. The technology was awarded the 2010 winner of best production technology for a company with fewer than 100 employees. The ESTSP can pump at a greater depth than other lift technologies. The design challenges included making the pump small enough to fit inside the well casing while also able to generate the high pressures necessary for pumping heavy oil. The ESTSP can compete directly against other lift technologies, including electric submersible pumps (ESPs). In the design, two shafts are separated by a timing gear. Each shaft has short sections of interlocking screws that do not touch, which lessens tension and the need for torque, lowering electricity consumption. The ESTSP is more efficient than ESP systems, particularly in more viscous mediums with high gas-to-oil ratios. The positive displacement pump interprets only volume and does not distinguish between gas and oil, functioning with gas content up to 97 percent. ESTSP can also handle more sand than ESP because it does not rely on centrifugal force. A patented screw design also helps prevent pump seizure resulting from sand and other solids. The pump uses downhole electric motors from other manufacturers. The inherent efficiencies of twin screw pumps give the technology the potential to replace conventional ESPs. 2 figs.

  18. [Twin delivery with the first twin in breech position. A study of 137 continuous cases].

    Science.gov (United States)

    Bourtembourg, A; Ramanah, R; Jolly, M; Gannard-Pechin, E; Becher, P; Cossa, S; Mulin, B; Maillet, R; Riethmuller, D

    2012-04-01

    The first twin (T1) in breech position is at risk of complications during vaginal delivery, making the choice of the appropriate delivery route highly important. Although British and American practice guidelines recommend the cesarean section, the French National College of Obstetricians and Gynecologists concluded that there was not enough data to choose one delivery route or the other. In this context, we set out to describe practices in our centre. Our retrospective study was conducted at a level III labor ward between January 1st, 1995 and December 31st, 2006. One hundred and thirty-seven twin pregnancies at more than 26 gestational weeks (GW), with T1 in breech and T2 in any position, were included. A cesarean section was performed before labor in 60.6 % cases. Among the 54 (39.4 %) cases where a trial of labor was accepted, 29 patients (53.7 % success rate) delivered vaginally and 25 (46.3 %) had a cesarean section during labor. No statistical difference was observed between the neonatal outcomes after cesarean section as compared to vaginal birth. However, a significant relationship was found between delivery route and parity. Less than one-third of nulliparas versus two-third of patients with a history of at least one delivery, having trials of labor, ultimately gave birth vaginally. Thus, we observed a high rate of cesarean section during labor in nulliparas (68 % of the initially accepted trials of labor). Our study is the first one that clearly shows that the success rate of the trial of labor is closely related to a history of vaginal birth. Following these results and because of more than two-third of cesarean section during labor in nulliparas, we subsequently plan an elective cesarean section at the 38th GW for nulliparas with twin pregnancies and T1 in breech position. Nevertheless, if any of these patients go in labor before the cesearean section, a careful trial of labor is offered. Copyright © 2011 Elsevier Masson SAS. All rights

  19. ARE THE TWINS, BORN AFTER AN IVF-ET PROCEDURE ANY DIFFERENT THAN TWINS, BORN AFTER SPONTANEOUS CONCEPTION?

    Directory of Open Access Journals (Sweden)

    Sara Korošec

    2003-12-01

    Full Text Available Background. Multiple pregnancy is in itself already a risk factor for the course and outcome of the pregnancy and birth. Its frequency in in-vitro fertilisation is approximately twenty fold in comparison to natural conception which is also why it is one of the main problem areas of pregnancy and birth after an IVF-ET procedure. The aim of our research is to determine whether the twins, born after an IVF-ET procedure are any different than twins, born after spontaneous conception.Methods. The research was retrospective in nature. It included 1511 twin pregnancy patients who gave birth to twins between April 1987 and May 1995 and between January 1997 and December 1999. Our research group consisted of 255 mothers and 510 twins, born after an IVF-ET procedure. The research was divided into a cohort and controlled study. In the cohort study the research group was compared to the entire Ljubljana cohort of 1256 mothers and 2512 twins resulting from spontaneous conception. In the controlled study 93 mothers and 186 twins from the research group were compared with 93 mothers and 186 newborns after spontaneous conception. In this group the mothers matched the research group in age, parity and birth year. The course of and complications during the pregnancy, and the course, complications and outcome of the birth as well as the characteristics of the newborns were compared.Results. Certain serious complications during the course of the pregnancy, including hypertension, gestation diabetes and threatened preterm labours, were no more frequent with the IVF group of mothers with twin pregnancy than with the control group. However more bleeding in the first trimester and less proteinuria were determined in comparison to the control group. During the course of birth and its outcome more premature labours were determined (62.3–68.8% vs. 51.4– 50.5%, a 6 to 7 days lower average gestation age, a coresponding birth weight, three times more elective and urgent

  20. Twin boundaries, interfaces and modulated structures in martensites. [Proper and improper ferroelastic martensites; In-Tl

    Energy Technology Data Exchange (ETDEWEB)

    Barsch, G.R.

    1992-09-30

    Theoretical studies were pursued with supporting experimental investigations (In-Tl) on the statics, dynamics, and statistical mechanics of twin boundaries, twin bands, and pretransformation structural modulations in proper and improper ferroelastic martensites.

  1. The vanishing twin: a major determinant of infant outcome in IVF singleton births

    DEFF Research Database (Denmark)

    Pinborg, Anja; Lidegaard, Ojvind; Andersen, Anders Nyboe

    2006-01-01

    This article attempts to assess the frequency of vanishing twins in assisted reproductive and spontaneously conceived pregnancies, including in-vitro fertilization (IVF), and its impact on the live-born surviving twin....

  2. Irrational twins in α-NiSO4.6H2O crystals

    International Nuclear Information System (INIS)

    Stojanoff, V.; Pimentel, C.A.F.

    1982-06-01

    α - NiSO 4 6H 2 O crystals were grown from a monocrystalline seed in a saturated solution. X-ray studies has revealed the presence of twins. A possible origin for this twinning is discussed. (Author) [pt

  3. Atomic-Level Understanding of "Asymmetric Twins" in Boron Carbide.

    Science.gov (United States)

    Xie, Kelvin Y; An, Qi; Toksoy, M Fatih; McCauley, James W; Haber, Richard A; Goddard, William A; Hemker, Kevin J

    2015-10-23

    Recent observations of planar defects in boron carbide have been shown to deviate from perfect mirror symmetry and are referred to as "asymmetric twins." Here, we demonstrate that these asymmetric twins are really phase boundaries that form in stoichiometric B(4)C (i.e., B(12)C(3)) but not in B(13)C(2). TEM observations and ab initio simulations have been coupled to show that these planar defects result from an interplay of stoichiometry, atomic positioning, icosahedral twinning, and structural hierarchy. The composition of icosahedra in B(4)C is B(11)C and translation of the carbon atom from a polar to equatorial site leads to a shift in bonding and a slight distortion of the lattice. No such distortion is observed in boron-rich B(13)C(2) because the icosahedra do not contain carbon. Implications for tailoring boron carbide with stoichiometry and extrapolations to other hierarchical crystalline materials are discussed.

  4. Twins for epigenetic studies of human aging and development

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; Thomassen, Mads

    2013-01-01

    Most of the complex traits including aging phenotypes are caused by the interaction between genome and environmental conditions and the interface of epigenetics may be a central mechanism. Although modern technologies allow us high-throughput profiling of epigenetic patterns already at genome level...... and environmental contributions to human diseases and complex traits. In the era of functional genomics, the valuable sample of twins is helping to bridge the gap between gene activity and the environments through epigenetic mechanisms unlimited by DNA sequence variations. We propose to extend the classical twin...... design to study the aging-related molecular epigenetic phenotypes and link them with environmental exposures especially early life events. Different study designs and application issues will be highlighted and novel approaches introduced with aim at making uses of twins in assessing the environmental...

  5. Internal strain and texture evolution during deformation twinning in magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W. [MS-H805, BLDG 622, TA-53, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: dbrown@lanl.gov; Agnew, S.R. [Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Bourke, M.A.M. [MS-H805, BLDG 622, TA-53, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Holden, T.M. [Northern Stress Technologies, Deep River, Ont., K0J 1P0 (Canada); Vogel, S.C. [MS-H805, BLDG 622, TA-53, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tome, C.N. [MS-H805, BLDG 622, TA-53, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2005-06-15

    The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically 'hard' deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

  6. Change in Depression Symptomatology and Cognitive Function in Twins

    DEFF Research Database (Denmark)

    Petersen, Inge; McGue, Matt; Tan, Qihua

    2016-01-01

    A complex interrelation exists between change in depression symptomatology and cognitive decline. Studies indicate either that depression is a direct risk factor for cognitive change over time, or vice versa. Longitudinal twin studies provide the possibility to unravel cause and effect of correla...... to detect any causal association between change in depressive symptomatology and cognitive decline in middle-aged and elderly people over a 10-year interval.......A complex interrelation exists between change in depression symptomatology and cognitive decline. Studies indicate either that depression is a direct risk factor for cognitive change over time, or vice versa. Longitudinal twin studies provide the possibility to unravel cause and effect...... of correlated traits. Here, we have applied twin modeling approaches to shed light on the genetic correlation between both level and change of depression symptomatology and cognitive functioning, and to further explore the bidirectionality of any such correlation using assessments of both phenotypes at two...

  7. On the deformation twinning of Mg AZ31B

    DEFF Research Database (Denmark)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette

    2015-01-01

    extension twinning as a deformation mode due to the lack of easy-slip systems. In this work, experiments were devised to study extension twinning in a polycrystalline Mg alloy AZ31B with a strong basal rolling texture by tensile deformation parallel to the plate normal. Three-dimensional synchrotron X......Crystals with a hexagonal close-packed (HCP) structure are inherently anisotropic, and have a limited number of independent slip systems, which leads to strong deformation textures and reduced formability in polycrystalline products. Tension along the c-axis of the crystal ideally activates...... and grain volumes are used to construct various 3D microstructures and model them with a Crystal Plasticity Finite Element (CPFE) code. It is observed that the average grain-resolved stress did not always select the highest ranked Schmid factor twin variant. In fact, the contribution of lower ranked...

  8. Flexoelectricity and the polarity of complex ferroelastic twin patterns

    Science.gov (United States)

    Salje, Ekhard K. H.; Li, Suzhi; Stengel, Massimiliano; Gumbsch, Peter; Ding, Xiangdong

    2016-07-01

    We study, by means of an atomistic toy model, the interplay of ferroelastic twin patterns and electrical polarization. Our molecular dynamics simulations reproduce polarity in straight twin walls as observed experimentally. We show, by making contact with continuum theory, that the effect is governed by linear flexoelectricity. Complex twin patterns, with very high densities of kinks and/or junctions, produce winding structures in the dipolar field, which are reminiscent of polarization vortices. By means of a "cold shearing" technique, we produce patches with high vortex densities; these unexpectedly show a net macroscopic polarization even if neither the original sample nor the applied mechanical perturbation breaks inversion symmetry by itself. These results may explain some puzzling experimental observations of "parasitic" polarity in the paraelectric phase of BaTi O3 and LaAl O3 .

  9. Association between obesity and asthma in a twin cohort

    DEFF Research Database (Denmark)

    Thomsen, S F; Ulrik, C S; Kyvik, Kirsten Ohm

    2007-01-01

    individuals participated in a nationwide questionnaire study, where data on height, weight and asthma were collected. Latent factor models of genetic and environmental effects were fitted using maximum likelihood methods. RESULTS: The age-adjusted risk of asthma was increased both in obese females, OR = 1......BACKGROUND: Obesity is linked to asthma in a yet poorly understood manner. We examined the relationship between obesity and asthma in a population-based sample of twins. METHODS: From the cohorts born between 1953 and 1982, who were enrolled in The Danish Twin Registry, a total of 29 183 twin.......96 (1.45-2.64), P obese males, OR = 1.59 (1.08-2.33), P = 0.02. According to best-fitting models, the heritability for obesity was 81% in males and 92% in females, whereas the heritability for asthma was 78% and 68% in males and females respectively. The age-adjusted genetic...

  10. Multiple maxillary and mandibular supernumerary teeth in twins: 5-year follow-up

    OpenAIRE

    Liu, Jeng-Fen; Chen, Hui-Ling

    2014-01-01

    This is a case report of multiple supernumerary teeth of identical twins with 5 years of follow-up. The occurrence of supernumerary teeth in twins is an unusual event. This case report describes 7-year-old Taiwanese twin brothers who both presented with multiple supernumerary teeth in the premaxillary and mandibular premolar regions. The supernumerary premolars developed much later than the premaxillary supernumerary teeth in these twins. The supernumerary premolars caused impaction of the ma...

  11. Similarities in drinking behavior of twin's friends: Moderation of heritability of alcohol use

    OpenAIRE

    Poelen, E.A.P.; Engels, R.C.M.E.; Scholte, R.H.J.; Boomsma, D.I.; Willemsen, G.

    2009-01-01

    Previous research has indicated that friends' drinking may influence alcohol use in adolescents and young adults. We explored whether similarities in the drinking behavior of friends of twins influence the genetic architecture of alcohol use in adolescence and young adulthood. Survey data from The Netherlands Twin Register were available for 1,526 twin pairs aged 16-25 years. We categorized the twin pairs as concordant (both report similar alcohol use in their friends) or discordant for the a...

  12. Twin–Twin Transfusion Syndrome Presenting as Polyhydramnios in Both Fetuses Secondary to Spontaneous Microseptostomy

    OpenAIRE

    David N. Hackney; Nahla Khalek; Julie Moldenhauer; Tulin Ozcan

    2013-01-01

    The presence of polyhydramnios and oligohydramnios is pathognomonic for twin-twin transfusion syndrome (TTTS). However, polyhydramnios of both twins can exist in TTTS in the setting of a septostomy of the dividing membrane. In prior reported cases of dual polyhydramnios TTTS, the septostomy was identified through either ultrasound or fetoscopy thus helping to establish the diagnosis of TTTS with an unusual presentation. The presented case is a set of monochorionic, diamniotic twins who presen...

  13. Os odontoideum in identical twins: Comparative gene expression analysis.

    Science.gov (United States)

    Straus, David; Xu, Shunbin; Traynelis, Vincent C

    2014-01-01

    Os odontoideum is a well identified anomaly of the craniovertebral junction. Since its initial description, there has been a continuous debate regarding the nature of its etiology: Whether congenital or traumatic. We sought to compare the gene expression profiles in patients with congenital os odontoideum, those with traumatic os odontoideum and controls. We have evaluated a pair of identical twins both with os odontoideum. We identified two additional patients with and four subjects without os odontoideum. We analyzed the gene expression profiles in these patients using a custom TaqMan microarray and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The relative gene expression profiles in the two identical twins, the two nontwin patients with os odontoideum and the controls were assessed. A total of 213 genes with significantly different expression between the twin os odontoideum patients and the subjects without os odontoideum were detected. CACNG6, PHEX, CACNAD3, IL2, FAS, TUFT1, KIT, TGFBR2, and IGF2 were expressed at levels greater than 100-fold more in the twins. There were six genes with significantly different expression profiles in the twins as compared with the nontwin os odontoideum patients: CMK4, ATF1, PLCG1, TAB1, E2F3, and ATF4. There were no statistically significant differences in gene expression in the four patients with os odontoideum and the subjects without. Trends, however, were noted in MMP8, KIT, HIF1A, CREB3, PWHAZ, TGFBR1, NFKB2, FGFR1, IPO8, STAT1, COL1A1, and BMP3. Os odontoideum has multiple etiologies, both traumatic and congenital and perhaps some represent a combination of the two. This work has identified a number of genes that show increased expression in a pair of twins with congenital os odontoideum and also demonstrates trends in gene expression profiles between a larger group of os odontoideum patients and non-os patients. A number of these genes are related to bone morphogenesis and maintenance.

  14. Analysis of occlusal characteristics of identical homozygous twins

    Directory of Open Access Journals (Sweden)

    Kučević Esad

    2017-01-01

    Full Text Available Background/Aim. Functionally stable occlusion is characterized by optimal and orthopedic stable position of the condyle, harmonious contact ratio of upper and lower teeth in the final occlusal position of the mandible, optimal relationship of dental arches at the eccentric movement of the lower jaw and stable interocclusal space in physiological position. As there are no ideal order of teeth and absolute intermaxilar harmony nor individually acceptable standards or prototype of functionally optimal occlusion, the aim of this study was to analyze occlusal characteristics of identical twins. Methods. This clinical epidemiological and functional study involved 30 pairs of identical twins, both males and females, aged 20 to 40 years. The main criterion for the selection of participants was preserved function of orofacial system, as a precondition for application of the Peer Assessment Rating (PAR index, which is the most reliable tool for diagnosing malocclusion and evaluating occlusal parameters: the distance between the contact points of agonists of front segments of the dental arches, side occlusion of the sagittal, vertical and transversal position, overjet, anterior crossbite, deep and open bite, overbite of incisors and relationship of middle dental arches. Results. Using t-test for independent samples, no significant difference in the values of PAR index, according to gender, was established. The average difference of 0.833 between the twin groups (for male twins: x¯ = 7.97, SD = 6.625; for female twins: x¯ = 7.13, SD = 5.606 was not statistically significant [t (58 = 0.526; p = 0.601; 95% confidence interval: -2.339–4.005]. Conclusion. The lack of significant differences in occlusal PAR index analysis in both the same and different twin groups, implies the dominance of hereditary factors.

  15. Age and mass of solar twins constrained by lithium abundance

    Science.gov (United States)

    Do Nascimento, J. D., Jr.; Castro, M.; Meléndez, J.; Bazot, M.; Théado, S.; Porto de Mello, G. F.; de Medeiros, J. R.

    2009-07-01

    Aims: We analyze the non-standard mixing history of the solar twins HIP 55 459, HIP 79 672, HIP 56 948, HIP 73 815, and HIP 100 963, to determine as precisely as possible their mass and age. Methods: We computed a grid of evolutionary models with non-standard mixing at several metallicities with the Toulouse-Geneva code for a range of stellar masses assuming an error bar of ±50 K in T_eff. We choose the evolutionary model that reproduces accurately the observed low lithium abundances observed in the solar twins. Results: Our best-fit model for each solar twin provides a mass and age solution constrained by their Li content and T_eff determination. HIP 56 948 is the most likely solar-twin candidate at the present time and our analysis infers a mass of 0.994 ± 0.004 {M⊙} and an age of 4.71 ± 1.39 Gyr. Conclusions: Non-standard mixing is required to explain the low Li abundances observed in solar twins. Li depletion due to additional mixing in solar twins is strongly mass dependent. An accurate lithium abundance measurement and non-standard models provide more precise information about the age and mass more robustly than determined by classical methods alone. The models are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/687 or via http://andromeda.dfte.ufrn.br

  16. Sleep terrors in children: a prospective study of twins.

    Science.gov (United States)

    Nguyen, Bich Hong; Pérusse, Daniel; Paquet, Jean; Petit, Dominique; Boivin, Michel; Tremblay, Richard E; Montplaisir, Jacques

    2008-12-01

    There is growing evidence that genetic factors are involved in the occurrence of sleep terrors. Twin studies provide invaluable information regarding genetic and environmental factors that can affect the manifestation of the disease; however, most previous twin studies on sleep terrors were performed retrospectively or with a sample that was too small to yield conclusive results. The aim of this large prospective study was to clarify the genetic and environmental contributions to sleep terrors in childhood. In all, 390 pairs of monozygotic and dizygotic twins were recruited at birth for a longitudinal study. The prevalence and frequency of sleep terrors were assessed at 18 and 30 months of age with a questionnaire administered to the biological mother of the twins. Zygosity was determined by a questionnaire and genotyping. The prevalence and polychoric correlation for each type of twins were calculated. Structural-equation modeling was used to determine the proportion of variance attributable to additive genetic, shared, and nonshared environmental factors. The prevalence of sleep terrors was 36.9% at 18 months and 19.7% at 30 months; 49% of affected children were boys, and 51% were girls. At 18 months, the polychoric correlations were 0.63 for monozygotic and 0.36 for the dizygotic twins. These were 0.68 (monozygotic) and 0.24 (dizygotic) at 30 months. Our model-fitting analysis showed that sleep terrors were explained by a 2-component model at 18 months (43.7% additive genetic effects and 56.3% nonshared environment) and at 30 months (41.5% additive genetic effects and 58.5% nonshared environment). These results strongly support the heritability of sleep terrors. There also seems to be continuity in genetic effects with the persistence of sleep-terror symptoms.

  17. Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins.

    Science.gov (United States)

    Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F

    2015-10-01

    Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Academic clinical research center. 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a "normal" (7-9 h/24) and "short" (sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. © 2015 Associated Professional Sleep Societies, LLC.

  18. An elasto-plastic self-consistent model with hardening based on dislocation density, twinning and de-twinning: Application to strain path changes in HCP metals

    Energy Technology Data Exchange (ETDEWEB)

    Zecevic, Milovan [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States); Knezevic, Marko, E-mail: marko.knezevic@unh.edu [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States); Beyerlein, Irene J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tomé, Carlos N. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-06-25

    In this work, we develop a polycrystal mean-field constitutive model based on an elastic–plastic self-consistent (EPSC) framework. In this model, we incorporate recently developed subgrain models for dislocation density evolution with thermally activated slip, twin activation via statistical stress fluctuations, reoriented twin domains within the grain and associated stress relaxation, twin boundary hardening, and de-twinning. The model is applied to a systematic set of strain path change tests on pure beryllium (Be). Under the applied deformation conditions, Be deforms by multiple slip modes and deformation twinning and thereby provides a challenging test for model validation. With a single set of material parameters, determined using the flow-stress vs. strain responses during monotonic testing, the model predicts well the evolution of texture, lattice strains, and twinning. With further analysis, we demonstrate the significant influence of internal residual stresses on (1) the flow stress drop when reloading from one path to another, (2) deformation twin activation, (3) de-twinning during a reversal strain path change, and (4) the formation of additional twin variants during a cross-loading sequence. The model presented here can, in principle, be applied to other metals, deforming by multiple slip and twinning modes under a wide range of temperature, strain rate, and strain path conditions.

  19. Paradoxical scalloped placenta with polyhydramnios in twin-twin transfusion syndrome.

    Science.gov (United States)

    Chmait, Ramen H; Rossi, A Cristina; Quintero, Rubén A

    2007-01-01

    To describe the paradoxical occurrence of a scalloped placenta in the presence of polyhydramnios and assess its clinical significance in pregnancies complicated by twin-twin transfusion syndrome (TTTS) treated with laser therapy. All patients who underwent laser therapy for TTTS between January 2003 and April 2004 were studied. TTTS was diagnosed and staged using the Quintero staging system. Normally the placenta is characterized by undulations of the fetal-placental surface visible by ultrasound (scalloped placenta). Patients with polyhydramnios will typically have a flattened, smooth, non-scalloped placenta. Operative tapes were reviewed and placental type assigned. Pre-, intra-, and postoperative characteristics of each study patient were obtained. Fifteen of 120 patients (12.5%) were noted to have a scalloped placenta despite having polyhydramnios. There was no difference in mean gestational age at laser treatment (20.3+/-0.5 vs. 19.6+/-0.6 weeks, p=0.66) or in stage (p=0.07) between the two groups. The median and range preoperative maximum vertical pocket (MVP) in the recipient gestational sac differed significantly between the scalloped and non-scalloped patients (8.3 (8-12) vs. 10.5 (8-17), p=0.001). All 15 patients (100%) with a scalloped placenta required an amnioinfusion to expose all vascular anastomoses, while amnioinfusion was necessary in only 28 of the 105 patients (26.7%, por=8 cm in the recipient sac. Most patients will have a flattened placenta as a result of polyhydramnios in this sac. Our data show that a paradoxical scalloped placenta may still be present in approximately 12.5% of patients. This preoperative sonographic finding alerts to the potential need for amnioinfusion during laser therapy for TTTS to disclose all vessels to avoid missing placental vascular anastomoses. Amniocenteses should be avoided if possible in patients considering laser therapy to minimize the likelihood of iatrogenic placental scalloping.

  20. Unilateral twin interstitial ectopic pregnancy. A case report.

    Science.gov (United States)

    Starks, G C

    1980-08-01

    An unusual case of twin unilateral interstitial pregnancy with premature rupture of membranes and leiomyomata uteri is described. A review of the literature reveals only two previous cases of this type. On admission, the patient was diagnosed as having an intrauterine pregnancy of 27 weeks' gestation, with documented premature rupture of the membranes having occurred. An ultrasound was performed revealing a fibroid uterus, an anterior placenta and an gestation. Septicemia ensued, and antibiotics plus pitocin was begun; however, no uterine response occurred. A culdocentesis revealed free intraabdominal blood. Laparotomy followed, revealing a ruptured twin interstitial pregnancy with placenta accreta and leiomyomata of the uterus.