Patient Perception of Negative Non-Invasive Prenatal Testing Results

Non-invasive prenatal testing (NIPT) uses cell-free fetal DNA to assess for fetal aneuploidy during pregnancy. NIPT has higher detection rates and positive predictive values than previous methods; however, NIPT is not diagnostic. Studies suggest patients may underestimate the limitations of prenatal screening. Therefore, we conducted a prospective cross-sectional study of ninety-four women from genetic counseling clinics in Houston, Texas to assess patient understanding of the residual risk for aneuploidy after receiving a negative NIPT. The majority of participants (66%) understood the residual risk for Down syndrome following negative NIPT; however, 34% of participants indicated that negative NIPT completely eliminated the risk. Individuals with at least four years of college education were more likely to understand that NIPT does not eliminate the chance of trisomy 13/18 (p=0.012) and sex chromosome abnormality (p=0.039), and were more likely to understand which conditions NIPT tests for (p=0.021), compared to women with less formal education. These data demonstrate that despite the recent implementation of NIPT into obstetric practice, the majority of women are aware of its limitations after genetic counseling. However, clinicians may need to consider alternative ways to communicate the limitations of NIPT to those women with less formal education to ensure understanding

Implementation of non-invasive prenatal testing by semiconductor sequencing in a genetic laboratory

Objectives: To implement non-invasive prenatal testing (NIPT) for fetal aneuploidies with semiconductor sequencing in an academic cytogenomic laboratory and to evaluate the first 15-month experience on clinical samples. Methods: We validated a NIPT protocol for cell-free fetal DNA sequencing from maternal plasma for the detection of trisomy 13, 18 and 21 on a semiconductor sequencing instrument. Fetal DNA fraction calculation for all samples and several quality parameters were implemented in the workflow. One thousand eighty-one clinical NIPT samples were analysed, following the described protocol. Results: Non-invasive prenatal testing was successfully implemented and validated on 201 normal and 74 aneuploid samples. From 1081 clinical samples, 17 samples showed an abnormal result: 14 trisomy 21 samples, one trisomy 18 and one trisomy 16 were detected. Also a maternal copy number variation on chromosome 13 was observed, which could potentially lead to a false positive trisomy 13 result. One sex discordant result was reported, possibly attributable to a vanishing twin. Moreover, our combined fetal fraction calculation enabled a more reliable risk estimate for trisomy 13, 18 and 21. Conclusions: Non-invasive prenatal testing for trisomy 21, 18 and 13 has a very high specificity and sensitivity. Because of several biological phenomena, diagnostic invasive confirmation of abnormal results remains required

Lattice thermal conductivity of disordered NiPd and NiPt alloys

Numerical calculations of lattice thermal conductivity are reported for the binary alloys NiPd and NiPt. The present work is a continuation of an earlier paper by us [PRB, 72, 214207 (2005)]which had developed a theoretical framework for the calculation of configuration-averaged lattice thermal conductivity and thermal diffusivity in disordered alloys. The formulation was based on the augmented space theorem combined with a scattering diagram technique. In this paper we shall show dependence of the lattice thermal conductivity on a series of variables like phonon frequency, temperature and alloy composition. The temperature dependence of $\kappa(T)$ and its realtion to the measured thermal conductivity is discussed. The concentration dependence of $\kappa$ appears to justify the notion of a minimum thermal conductivity as discussed by Kittel, Slack and others. We also study the frequency and composition dependence of the thermal diffusivity averaged over modes. A numerical estimate of this quantity gives an idea about the location of mobility edge and the fraction of states in the frequency spectrum which is delocalized.Comment: 23 pages, 18 figure

Termination of Pregnancy After NonInvasive Prenatal Testing (NIPT): Ethical Considerations

This article explores the Nuffield Council on Bioethics’ recent report about non-invasive prenatal testing. Given that such testing is likely to become the norm, it is important to question whether there should be some ethical parameters regarding its use. The article engages with the viewpoints of Jeff McMahan, Julian Savulescu, Stephen Wilkinson and other commentators on prenatal ethics. The authors argue that there are a variety of moral considerations that legitimately play a significant role with regard to (prospective) parental decision-making in the context of NIPT, for example, views on the morality of abortion and understandings of the impact of disability on quality of life. The variable nature of such considerations, both singularly and combined, suggests that any approach to NIPT should be sensitive to and understanding of similarly variable parental assessments and decisions. The implications of the approach developed for current and future policies in this area are explored, along with the impact of such arguments on ideas about procreative beneficence

Anisotropic intrinsic anomalous Hall effect in ordered 3dPt alloys

By performing first principles calculations we investigate the intrinsic anomalous Hall conductivity (AHC) and its anisotropy in ordered L1o FePt, CoPt and NiPt ferromagnets, and their intermediate alloys. We demonstrate that the AHC in this family of compounds depends strongly on the direction of the magnetization in the crystal. We predict that such pronounced orientational dependence in combination with the general decreasing trend of the AHC when going from FePt to NiPt leads to a sign change of the AHC upon rotating the magnetization direction in the crystal of CoPt alloy. We also suggest that for a range of concentration x in Co(x)Ni(1-x)Pt alloy it is possible to achieve a complete quenching of the anomalous Hall current for a certain direction of the magnetization in the crystal. By analyzing the spin-resolved AHC in 3dPt alloys we endeavor to relate the overall trend of the AHC in these compounds to the changes in their densities of d-states around the Fermi energy upon varying the atomic number. Moreover, we show the generality of the phenomenon of anisotropic anomalous Hall effect by demonstrating its occurrence within the three-band tight-binding model.Comment: 10 page

Study of Phase Stability in NiPt Systems

We have studied the problem of phase stability in NiPt alloy system. We have used the augmented space recursion based on the TB-LMTO as the method for studying the electronic structure of the alloys. In particular, we have used the relativistic generalization of our earlier technique. We note that, in order to predict the proper ground state structures and energetics, in addition to relativistic effects, we have to take into account charge transfer effects with precision.Comment: 22 pages, 7 figures. Accepted for publication in JPC

Anomalous Hall effect in NiPt thin films

We study Hall effect in sputtered NixPt1-x thin films with different Ni concentrations. Temperature, magnetic field and angular dependencies are analyzed and the phase diagram of NiPt thin films is obtained. It is found that films with sub-critical Ni concentration exhibit cluster-glass behavior at low temperatures with a perpendicular magnetic anisotropy below the freezing temperature. Films with over-critical Ni concentration are ferromagnetic with parallel anisotropy. At the critical concentration the state of the film is strongly frustrated. Such films demonstrate canted magnetization with the easy axis rotating as a function of temperature. The magnetism appears via consecutive paramagnetic - cluster glass - ferromagnetic transitions, rather than a single second-order phase transition. But most remarkably, the extraordinary Hall effect changes sign at the critical concentration. We suggest that this is associated with a reconstruction of the electronic structure of the alloy at the normal metal - ferromagnet quantum phase transition.Comment: 12 pages, 17 figure