Normal Twin Research Articles

An Efficient Scheme to Detect Evil Twin Rogue Access Point Attack in 802.11 Wi-Fi Networks

The MAC layer of 802.11 protocol possess inherent weakness making it vulnerable to various security attacks like denial of service, deauthentication attack, flooding attacks, rogue access point (RAP) etc. In this manuscript we focus on evil twin attack. An evil twin is a RAP setup by cloning the MAC address and the Service Set IDentifier of an existing wireless access point (AP). An evil twin is setup so that the client(s) unknowingly connect to them under the pretext that they are connected to a genuine AP. Once a client is connected, an attacker eavesdrops on its communication to hijack client’s communication, re-direct clients to malicious websites, steal credentials of the clients connecting to it. Existing methods to detect the evil twin include maintaining white lists, patching AP/client, timing based solutions, protocol modifications etc. These methods usually require extensive setup and maintenance, have scalability and compatibility issues, require changes in protocol stack making them expensive to deploy and manage. The network conditions under normal and evil twin attack are almost similar thereby crafting a signature or defining an anomaly pattern usually leads to large amount of false positives. In this manuscript, we propose an IDS for detecting the evil twin attack, which addresses most of these issues associated with the existing detection mechanisms. Further the scheme is also proved to detect a single evil twin, multiple evil twins for single AP and multiple evil twins for multiple APs. The proposed IDS has been deployed in a lab environment and its detection rate exceeds 92% mark and the accuracy is 100% in all the runs.

White matter hyperintensities and vascular risk factors in monozygotic twins

Cerebral white matter hyperintensities (WMHs) have been associated with vascular risk factors, both of which are under genetic influence. We examined in a monozygotic twin sample whether the association between vascular risk and WMHs is influenced by overlapping genetic factors. We included 195 cognitively normal monozygotic twins (age = 70 ± 7 years), including 94 complete pairs. Regional WMH load was estimated using an automated algorithm. Vascular risk was summarized with the Framingham score. The within–twin pair correlation for total WMHs was 0.76 and for Framingham score was 0.77. Within participants, Framingham score was associated with total and periventricular WMHs (r = 0.32). Framingham score in 1 twin was also associated with total WMHs in the co-twin (r = 0.26). Up to 83% of the relation between both traits could be explained by shared genetic effects. In conclusion, monozygotic twins have highly similar vascular risk and WMH burden, confirming a genetic background for these traits. The association between both traits is largely driven by overlapping genetic factors.

Subsequent fertility, pregnancy, and gynecologic outcomes after fetoscopic laser therapy for twin-twin transfusion syndrome compared with normal monochorionic twin gestations

An improved survival and quality of life for neonatal survivors after fetoscopic laser therapy for twin-twin transfusion syndrome has been reported. However, little is known about the medium-term maternal effects after fetoscopic laser therapy with respect to reproductive and gynecologic outcomes. The objective of this study was to document reproductive, obstetric, gynecological, and psychological outcomes in women who underwent fetoscopic laser therapy for twin-twin transfusion syndrome. This was a monocentric controlled study on consecutive women who underwent fetoscopic laser therapy for twin-twin transfusion syndrome between 2007 and 2013 at the University Hospitals Leuven (cases; n= 198). Controls were women followed up during the same time period for an uncomplicated monochorionic diamniotic twin pregnancy and with an uneventful course (controls; n= 211). All patients received a questionnaire inquiring on their fertility, later pregnancies, and gynecological outcomes. The response rate was 50.4% (cases: n= 95; controls: n=109). Most baseline characteristics were similar across both groups. Women in the fetoscopic laser therapy group attempted a new pregnancy more frequently (34% [31 of 92] vs 21% [22 of 107] in controls; P < .05) and became pregnant more often (100% [31 of 31] vs 82% [18 of 22]; P<.05).We observed a shorter interpregnancy interval in cases than controls (median interval, 12 [interquartile range, 5-27] vs 24 [interquartile range, 15-30] months) (P < .05). This was also observed in cases who lost one or both fetuses or babies in the index pregnancy (median interval, 9 [interquartile range, 3.5-25.5] months; P < .05). The complication rate during subsequent pregnancies (26% [8 of 31] vs 11% [2 of 19]; P=.194) and at delivery (17% [5 of 30] vs 11% [2 of 19]; P= .554) were comparable. More women who underwent fetoscopic laser coagulation reported relevant psychological symptoms (44% [40 of 92] vs 21% [23 of 107]; P < .05). When only women in whom there was a double-surviving twin pair were considered, there were no differences in psychological symptoms compared with controls (16% [15 of 55] vs 21% [23 of 107]; P= .411). Gynecological problems were equally frequent in both groups (20% [18 of 92] vs 31% [33 of 107]; P= .069). No adverse medium-term maternal effects with respect to fertility, obstetric, and gynecological outcomes were observed after fetoscopic laser therapy. However, these women reported more psychological or emotional problems than women with monochorionic diamniotic who did not have laser therapy, in particular when this was complicated by a fetal loss.

A Case Report of Partial Molar Pregnancy Associated with a Normal Dizygotic Twin

A Case Report of Partial Molar Pregnancy Associated with a Normal Dizygotic Twin

Expression of Homeobox Gene HLX and its Downstream Target Genes are Altered in Placentae From Discordant Twin Pregnancies.

A discordant twin gestation, in which one fetus is significantly growth restricted, compared to the other normal twin, is a unique model that can be used to elucidate the mechanism(s) by which the intrauterine environment affects fetal growth. In many model systems, placental transcription factor genes regulate fetal growth. Transcription factors regulate growth through their activation or repression of downstream target genes that mediate important cell functions. The objective of this study was to determine the expression of the placental HLX homeobox gene transcription factor and its downstream target genes in dizygotic twins with growth discordance. In this cross-sectional study, HLX and its downstream target genes' retinoblastoma 1 (RB1) and cyclin kinase D (CDKN1C) expression levels were determined in placentae obtained from dichorionic diamniotic twin pregnancies (n = 23) where one of the twins was growth restricted. Fetal growth restriction (FGR) was defined as small for gestational age with abnormal umbilical artery Doppler indices when compared with the normal control co-twin. Homeobox gene HLX expression was significantly decreased at both the mRNA and protein levels in FGR twin placentae compared with the normal control co-twin placentae (p < .05). Downstream target genes CDKN1C and RB1 were also significantly decreased and increased, respectively, at both the mRNA and protein levels in FGR twin placentae compared with normal control co-twin placentae (p < .05). Together, these observations suggest an important association between HLX transcription factor expression and abnormal human placental development in discordant twin pregnancies.

Two cases of bovine holoacardius amorphus monsters

Two rare cases of holoacardius amorphus totalis monsters are reported herewith. The monsters were examined macroscopically, radiographically and histologically, whereas karyotyping was performed in one normal twin. Both monsters were covered with normal skin and hair, while histological examinations revealed a homogenous parenchyma. The first monster was congener to those previously reported, while the second is the smallest case (weight 21.3 gr) reported to date. In both cases, two days after calving, two corpora, lutea were found on the ovaries of the dams. The aetiology as well as the mechanisms of teratogenesis are discussed.

77 Monozygotic Twin Calves Production by Blastomere Separation Technique with Commercial Well-of-the-Well Culture Dish

Monozygotic twin bovine embryos can be produced by blastomere separation of 2-cell embryos and commercial well-of-the-well (WOW) culture dish (Hashiyada et al. 2016 Reprod. Fertil. Dev. 28, 178) obtaining 60% and 48% of blastocyst formation and monozygotic blastocyst pairs, respectively. The present study was conducted to evaluate the fertility of blastocysts derived from this production system in Japanese Black beef cattle. Embryos were produced using oocytes collected by ovum pick-up technique. TCM-199 supplemented with 5% calf serum (CS), Brackett-Oliphant solution supplemented with 10 mg mL−1 BSA, and CR1aa containing 5% CS, were used for each culture step: in vitro maturation, fertilization, and culture (IVM,IVF, and IVC). Two-cell stage embryos were obtained 24 to 27 h post-insemination. Zonae pellucidae were removed by exposure to 0.25% pronase. Then, embryos were separated into blastomeres by gentle pipetting in IVC medium. Each blastomere was introduced into a single conical microwell of 25 wells, each having a diameter and depth of ~287 μm and 168 μm (Dai Nippon Printing, Tokyo, Japan). Blastomeres in wells were cultured covered with a droplet of 2.5 μL of IVC medium/well. The developed blastocysts in pairs on 7 days post-insemination were used for transfer. Single embryos of monozygotic twin embryos were transferred to Japanese Black cattle with a generally small body frame to produce twin calves from a set of recipients. Twin embryos were transferred in pairs to unilateral of uterus of non-lactating Holstein cows. Pregnancy and twin pregnancy were determined at 30 days of gestation by ultrasonography and were reconfirmed at 60 days with detection of fetal loss. Statistical significance was analysed by Fisher’s exact test. There was no significant difference in pregnancy rate or twin pregnancy rate between single embryo transfer (7/14, 50% and 2/7, 28.6%) and twin embryo transfer (9/21, 42.9% and 4/21, 19%). In either transfer method, fetal loss was not observed in diagnosis carried out at 60 days by ultrasonography. To date, 2 pairs of twin calves have been obtained from twin pregnant cows by twin embryo transfer within the normal range of gestation length (286 and 288 days) and birth weight (31-40 kg). These results indicate that blastocysts developed from blastomeres separated from 2-cell embryos by culturing with commercial WOW culture dish had fertility similar to that of intact embryos derived from standard in vitro culture and further demonstrate the possibility of production of normal twin calves.

Microstructural characterizations on Mn-containing intermetallic phases in a high-pressure die-casting Mg–4Al–4RE–0.3Mn alloy

The types and the detailed structures of the Mn-containing phases in the high-pressure die-casting Mg–4Al–4RE–0.3Mn alloy were thoroughly investigated using transmission electron microscopy (TEM). The results reveal five Mn-containing intermetallic phases with different morphologies, namely the regular blocky phase, the irregular blocky phase, the interlaced lath-shaped phase, the nano-scale phase on the surface of or embedded in the Al11RE3 particles, and the nano-scale precipitate in the α-Mg matrix. The former twos belong to Al10RE2Mn5 but the latter one contains numerous normal (11.1) twins and orientation twins. In addition, the third one simultaneously contains Al10RE2Mn5 and Al8REMn4, of which both are coherent with each other and contain normal twins. Finally, the last two nano-scale Mn-containing phases on the surface of or embedded in Al11RE3 and precipitated in α-Mg grains are Al10RE2Mn7 and Al8Mn5, respectively.

Functional and effective whole brain connectivity using magnetoencephalography to identify monozygotic twin pairs

Resting-state functional connectivity patterns are highly stable over time within subjects. This suggests that such ‘functional fingerprints’ may have strong genetic component. We investigated whether the functional (FC) or effective (EC) connectivity patterns of one monozygotic twin could be used to identify the co-twin among a larger sample and determined the overlap in functional fingerprints within monozygotic (MZ) twin pairs using resting state magnetoencephalography (MEG). We included 32 cognitively normal MZ twin pairs from the Netherlands Twin Register who participate in the EMIF-AD preclinAD study (average age 68 years). Combining EC information across multiple frequency bands we obtained an identification rate over 75%. Since MZ twin pairs are genetically identical these results suggest a high genetic contribution to MEG-based EC patterns, leading to large similarities in brain connectivity patterns between two individuals even after 60 years of life or more.

Deformation mechanisms during large strain deformation of high Mn TWIP steel

The evolution of texture and microstructure has been studied up to very large strains (ɛt≈3.9) on a twinning induced plasticity (TWIP) steel. Different micromechanisms have been envisaged during different deformation regimes. At early stage of deformation, the mechanism is normal slip dominated, while deformation twining starts at ~20% rolling and increases up to ~40% deformation level. Further deformation takes place by macroscopic shear banding (SBs). A Brass (Bs) type texture forms and strengthens throughout the deformation, which has been simulated by visco-plastic self consistent (VPSC) modelling. The results of VPSC simulations correlate the relative contributions of normal slip, Shockley partials and twin activities at different strain levels, which were observed by microstructural investigation. The Lankford parameter is estimated from texture, indicate that above 70% deformation level, the material develops very high in-plane anisotropy.

Proteotyping Gene Dosage Effects in Genetic Diseases

Introduction and ObjectivesGene dosage imbalance is a general working hypothesis for studying the genetic diseases, such as human syndromes, because the DNA copy number variations (CNVs) are causal for many genetic diseases. However, recent important studies have showed that many CNVs resulting in mRNA changes only weakly influence corresponding protein abundances. Herein we show by proteome‐wide turnover analysis that CNV's substantially remodel the proteome. In the presentation we will discuss specific instances of CNV's varying in the extent and magnitude of affected loci, and disease phenotypes. These examples include trisomy 21 (T21) in human Down Syndrome, and Williams Syndrome (WBS) and 7dup‐ASD syndrome caused by 7q11.23 hemideletion or hemiduplication.MethodsWe utilized SWATH mass spectrometry (SWATH‐MS) to accurately quantify protein degradation through a pulse SILAC experiment (pSILAC) up to 24 hours. For T21, we used fetal skin fibroblasts derived from a pair of monozygotic twins discordant for T21. To validate the results, we also analyzed fibroblasts from 11 unrelated T21 individuals bearing Down Syndrome and 11 controls. For WBS, patient‐derived induced pluripotent stem cells were analyzed. Data were processed by OpenSWATH workflow. The transcript profiling was measured by RNA‐Seq.Results and DiscussionIn the case of Down Syndrome, we investigated the effect of T21 at the levels of transcript quantity, proteome quantity and protein turnover rate. We quantified 4056 unique proteins for expression and ~2200 proteins by pSILAC experiment for turnover analysis in both normal and T21 twins. The T21/normal fold‐change correlation between transcript and protein levels was extremely low, indicating substantial post‐transcriptional regulation and buffering effects in T21. Overall, the protein degradation was faster in trisomy cells than the controls. Remarkably, those Chr21 encoded proteins that are members of heteromeric protein complexes were largely exempt from responding to CNV alterations, primarily through accelerated protein degradation. Moreover, we found that both mitochondrial and cytosolic ribosomal proteomes were degraded heavily in T21, but different degree of translational regulation shaped their final, divergent expression levels. In the case of WBS, we found that proteins with significant differences in turnover at the pluripotent state are components of pathways involved in translation, ubiquitination, splicing and basal metabolism.ConclusionsOur data suggests that protein‐specific turnover presents a primary mechanism of proteome remodeling in response to DNA dosage alterations and thus highlighting a proteomic understanding of “gene dosage imbalance” in genetic disorders.Support or Funding InformationY.L. was supported by the European Research Council (ERC, consolidator grant number 616441‐DISEASEAVATARS). The group of RA was supported by was supported by ERC grants Proteomics v3.0 (AdG‐233226 Proteomics v.3.0) and AdG‐670821 Proteomics 4D), and the Swiss National Science Foundation (SNSF) grant number: 31003A_166435.

Placental characteristics in monochorionic twins with selective intrauterine growth restriction assessed by gradient angiography and three-dimensional reconstruction

Objective: To investigate the placental characteristics in selective intrauterine growth restriction (sIUGR) using gradient angiography and three-dimensional (3D) reconstruction from computed tomography (CT) scan data.Methods: This study included 23 sIUGR cases and 16 monochorionic twin-pregnancies without sIUGR. We injected nonionic iodinated contrast agents into the umbilical arteries and veins. Placental characteristics were analyzed after CT scanning and 3D reconstruction.Results: 73.9% of smaller twins in sIUGR cases had marginal or velamentous cord insertions and less placental sharing. The terminal branch of the arterial tree was scored III–IV in smaller sIUGR twins, while it was scored V–VII in normal monochorionic twins and larger sIUGR twins. Arterio-arterial (A-A) anastomoses presented in all monochorionic placentas. Veno-venous (V-V) anastomoses present in 83.3% (5/6) of Type III sIUGR cases, which was higher than observed in Type I–II cases. The mean diameters of A-A and V-V anastomoses were larger in Type III sIUGR cases.Conclusions: Gradient angiography and 3D placental models displayed different placental angioarchitectures and voluminal placental sharing among three types of sIUGR cases. Placental dysplasia in the smaller twin may cause abnormal cord insertion and unequal placental sharing. The inter-twin anatomoses influence the umbilical cord artery (UA) Doppler and natural pathogenesis of sIUGR.

Twin reversed arterial perfusion sequence/syndrome - An insight into the ultrasonographic features for prenatal diagnosis and review of literature with obstetric importance: Case series of two reports

We present two case reports of twin reversed arterial perfusion sequence - a rare type of twin-twin transfusion syndrome, wherein there maldevelopment of one twin and is supplied by the normal twin. Then, we discuss the importance of this entity and various measures required if such a situation is encountered.

Effects of growth-discordant twin pregnancies on thyroid function of neonates

Objective To investigate the effects of growth-discordant twin pregnancies on neonatal thyroid stimulating hormone (TSH) level and congenital hypothyroidism (CH). Methods A total of 3 444 live-birth twin neonates born between January 1, 2012 and December 30, 2014 in Ningbo City were enrolled. Blood samples via heel puncture were collected and tested. Incidence of CH in singleton and twin neonates was compared. Deviation of birth weight larger than 25% in twin neonates was set as the criteria for discordant growth. TSH and 17α-hydroxylase levels in CH twins and normal twins, with or without discordant growth, were compared. Chi-square and non-parametric statistics were performed for data analysis. Results The incidence of CH in twin neonates was 0.56% (19/3 444), higher than that in singleton neonates [0.09% (203/225 712), χ2=76.225, P<0.01]. Among nineteen CH twins, CH occurred in both twins in eight cases (four twins) and in one of the twins in eleven cases. The gestational age at birth in the eight CH twins were less than 37 weeks, with four males and four females; five were low birth weight infants; one twin were dichorionic, and three twins were monochorionic. In the eleven cases of CH occurring in one of the twins, the gestational age was less than 37 weeks in nine cases, eight were low birth weight infants, six were male and five female; seven were monochorionic and four were dichoronic twins. Five cases of temporary hypothyroidism were all low birth weight infants among the growth-discordant twins. CH cases in growth-discordant group had lower birth weight than their normal twins [M(P25-P75), 2 100 (1 800-2 600) vs 2 770 (2 530-2 960) g, Z=4.369], and a higher TSH level [15.4 (11.8-18.5) vs 6.4 (4.8-7.9) mU/L, Z=6.339] (both P<0.05). In normal twins with or without discordant growth, the neonates with a lower birth weight had a higher TSH level [3.6(2.5-4.7) vs 2.4(1.8-2.9) mU/L, Z=0.962] in weight consistent group, compared with 6.0(4.4-7.8) vs 3.4(1.9-4.1) mU/L in weight inconsistent group (Z=4.369), both P<0.05. Conclusions In the growth-discordant twins, neonates with a lower birth weight have a higher TSH level and a higher risk of temporary hypothyroidism. Key words: Congenital hypothyroidism; Thyrotropin; Twins; Infant, low birth weight

Incidence of Neonatal Infection in South Sinai, Egypt

Background: The incidence of neonatal infection varies from one place to another, and also within the same nursery depending on conditions predisposing to infection. Objectives: The current study aimed to determine the incidence of neonatal infection (NICUs) in South Sinai neonatal intensive care units, Egypt. Methods: The study included 1023 neonates admitted to neonatal intensive care units in the South Sinai state hospitals from January 2010 to September 2014 and scanned for demographic data and the potential risk factors for neonatal septicemia. Results: The Incidence of septicemia in the NICUs of South Sinai state hospitals was 8.6% and mortality rate among sepsis cases (sepsis fatality rate) was about 25%. The percentage of cases with late-onset sepsis (68.2%) was predominant compared to the early-onset sepsis (31.8%). Hospital acquired infections represented 30.7 % of sepsis cases. Male neonates, preterm, low birth weight babies, normal vaginal deliveries, twin deliveries and multipara mothers and premature rupture of membranes were significantly associated with more incidence of sepsis among the study population. There was no statistical significant difference (P > 0.05) between sepsis and non-sepsis cases regarding the maternal age, site of delivery and presence of congenital anomalies among the study population. Conclusions: Prevalence of septicemia in neonatal intensive care units in South Sinai state hospitals was about 8.6% due to the abundance of risk factors in this area.

Salmonid fish: model organisms to study cardiovascular morphogenesis in conjoined twins?

BackgroundThere is a gap in knowledge regarding the cardiovascular system in fish conjoined twins, and regarding the cardiovascular morphogenesis of conjoined twins in general. We examined the cardiovascular system in a pair of fully developed ventrally conjoined salmonid twins (45.5 g body weight), and the arrangement of the blood vessels during early development in ventrally conjoined yolk sac larvae salmonid twins (<0.5 g body weight).ResultsIn the fully developed twins, one twin was normal, while the other was small and severely malformed. The mouth of the small twin was blocked, inhibiting respiration and feeding. Both twins had hearts, but these were connected through a common circulatory system. They were joined by the following blood vessels: (i) arteria iliaca running from arteria caudalis of the large twin to the kidney of the small twin; (ii) arteria subclavia running from aorta dorsalis of the large twin to aorta dorsalis of the small twin; (iii) vena hepatica running from the liver of the small twin into the sinus venosus of the large twin. Among the yolk sac larvae twins investigated, distinct vascular connections were found in some individuals through a joined v. vitellina hepatica.ConclusionsVentrally conjoined fish twins can develop cardiovascular connections during early development, enabling a normal superior twin to supply a malfunctioning twin with oxygen and nutrients. Since the yolk sac in salmonids is transparent, twinning in salmonids may be a useful model in which to study cardiovascular morphogenesis in conjoined twins.Electronic supplementary materialThe online version of this article (doi:10.1186/s12861-016-0125-x) contains supplementary material, which is available to authorized users.

Genome-wide placental DNA methylation analysis of severely growth-discordant monochorionic twins reveals novel epigenetic targets for intrauterine growth restriction.

BackgroundIntrauterine growth restriction (IUGR), which refers to reduced fetal growth in the context of placental insufficiency, is etiologically heterogeneous. IUGR is associated not only with perinatal morbidity and mortality but also with adult-onset disorders, such as cardiovascular disease and diabetes, posing a major health burden. Placental epigenetic dysregulation has been proposed as one mechanism that causes IUGR; however, the spectrum of epigenetic pathophysiological mechanisms leading to IUGR remains to be elucidated. Monozygotic monochorionic twins are particularly affected by IUGR, in the setting of severe discordant growth. Because monozygotic twins have the same genotype at conception and a shared maternal environment, they provide an ideal model system for studying epigenetic dysregulation of the placenta.ResultsWe compared genome-wide placental DNA methylation patterns of severely growth-discordant twins to identify novel candidate genes for IUGR. Snap-frozen placental samples for eight severely growth-discordant monozygotic monochorionic twin pairs were obtained at delivery from each twin. A high-resolution DNA methylation array platform was used to identify methylation differences between IUGR and normal twins. Our analysis revealed differentially methylated regions in the promoters of eight genes: DECR1, ZNF300, DNAJA4, CCL28, LEPR, HSPA1A/L, GSTO1, and GNE. The largest methylation differences between the two groups were in the promoters of DECR1 and ZNF300. The significance of these group differences was independently validated by bisulfite pyrosequencing, implicating aberrations in fatty acid beta oxidation and transcriptional regulation, respectively. Further analysis of the array data identified methylation changes most prominently affecting the Wnt and cadherin pathways in the IUGR cohort.ConclusionsOur results suggest that IUGR in monozygotic twins is associated with impairments in lipid metabolism and transcriptional regulation as well as cadherin and Wnt signaling. We show that monozygotic monochorionic twins discordant for growth provide a useful model to study one type of the epigenetic placental dysregulation that drives IUGR.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-016-0238-x) contains supplementary material, which is available to authorized users.

Increased Fetal Plasma Erythropoietin in Monochorionic Twin Pregnancies With Selective Intrauterine Growth Restriction and Abnormal Umbilical Artery Doppler

Hypoxia is the primary stimulus for the production of erythropoietin (EPO) in both fetal and adult life. Here, we investigated fetal plasma EPO concentrations in monochorionic (MC) twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery (UA) Doppler. We diagnosed sIUGR in presence of (1) birth-weight discordance >20% and (2) either twin with a birth weight <10th percentile. An abnormal UA Doppler was defined as a persistent absent-reverse end diastolic flow (AREDF). The intertwin EPO ratio was calculated as the plasma EPO level of the smaller (or small-for-gestational-age) twin divided by the EPO concentration of the larger (or appropriate-for-gestational-age (AGA)) twin. Thirty-two MC twin pairs were included. Of these, 17 pairs were normal twins (Group 1), seven pairs were twins with sIUGR without UA Doppler abnormalities (Group 2), and eight pairs were twins with sIUGR and UA Doppler abnormalities (Group 3). The highest EPO ratio was identified in Group 3 (p < .001) but no significant differences were observed between Groups 1 and 2. Fetal hemoglobin levels did not differ significantly in the three groups, and fetal EPO concentration did not correlate with gestational age at birth. We conclude that fetal plasma EPO concentrations are selectively increased in MC twin pregnancies with sIUGR and abnormal UA Doppler, possibly as a result of uncompensated hypoxia.

Prenatal diagnosis of thalassemia in twin pregnancies in mainland China

The aim of this study was to describe our experience with prenatal diagnosis of thalassemia in twin pregnancies at a tertiary referral centre in mainland China. All cases of twin pregnancies at risk of α- or β-thalassemias were followed over an eight-year period. There were 32 twin pregnancies at a mean gestation of 14 weeks (range, 11–21 weeks) at risk of thalassemias, including 19 at risk of α-thalassemia and 13 at risk of β-thalassemia. Chorionicity was determined by ultrasound before prenatal diagnosis. In 19 twin pregnancies at risk of α-thalassemia, there were four where both foetuses were affected, 13 where both foetuses were not affected, and two where one foetus was affected and the other one was not affected. In 13 twin pregnancies at risk of β-thalassemia, there were five where both foetuses were affected, six where both foetuses were not affected, and two where one foetus was affected and the other one was not affected. The pregnancies with two affected foetuses were aborted (including four affected by α-thalassemia and five affected by β-thalassemia), and in pregnancies with one normal twin and one affected twin, the affected foetuses were selectively aborted (including two twins affected by α-thalassemia, and two twins affected by β-thalassemia). Efforts should be taken to reduce the risks of the mother and foetuses in prenatal diagnosis without compromising the precise diagnosis.

Tomato yield, nitrogen uptake and water use efficiency as affected by planting geometry and level of nitrogen in an arid region

Water has always been the main factor limiting crop production in arid and semi-arid regions where rainfall is insufficient to meet crop demand. The invite to improve water use efficiency and crop productivity, to ensure future food security, has never been more urgent. Tomato yield performance was studied under different planting methods combined with different nitrogen (N) levels to evaluate the potentials and constraints of plant arrangement under drip irrigation for sustaining crop yield, N uptake, N use efficiency (NUE) and water use efficiency (WUE). Three planting methods were tested included arrangement of tomato plants in single rows, 100cm apart (SR), normal twin rows at 40/160cm alternately (NT) and dense twin rows at 40/100cm alternately (DT), which resulted in rising total plant population by 150% as high as SR and NT. This was done along with four N levels (120, 180, 240 and 300kgNha−1), applied continuously by drip irrigation system. Drip laterals were laid out along each single row or in the center of the twin rows; consequently the relative number of laterals and water applied were reduced by 50% and 75% for NT and DT, respectively compared with SR. Dense twin planting produced 24% higher tomato fruit yield over SR although 75% of irrigation water was applied. Otherwise, NT with 50% saving in irrigation water and cost of drip laterals can be realized by loss only 15% fruit yield as compared with SR. Nitrogen supply tended to increase tomato fruit yield significantly up to the highest level of N with all planting methods. The interaction effect of planting method×level of N was significant for almost yield components. Nitrogen supply increased tomato N uptake linearly with maximum N removal from the field 193kgha−1 under DT and N300 treatment combination, which contributed to higher fruit yield and total dry biomass. The lowest N treatment (N120) gave the higher N recovery with all planting methods, despite the sand texture of the soil. NUE was higher under DT as compared with SR but the NUE consistently decreased with increase level of N supply with all planting methods. WUE of both twin planting were higher (69% for NT and 64% for DT) compared with SR indicating to efficient use of water applied under this method of planting. The results of this study suggest that dense twin planting can be viable and rational practice to increase crop yield and saving substantial amount of irrigation water as well as cost of drip laterals.