Polarization-Sensitive Photoluminescence from Aligned Carbon Chains Terminated by Gold Clusters.

We synthesize a thin film composed of long carbyne chains terminated by gold clusters and study its optical properties. The presence of gold particles stabilizes longer chains and leads to their alignment. We show that the gold clusters also act as a source of electron doping, thus, changing the intensity of photoluminescence from quadratic dependence on the pumping intensity without gold to linear with gold. We also observe that the excitation of the film at the gold plasmon frequency causes the blue shift of photoluminescence and estimate, on the basis of this effect, the minimum length of the carbyne chains. The high degree of alignment of the gold-terminated carbyne chains results in strongly anisotropic light absorption characterized by a distinctive cosine dependence on the angle between the carbyne molecule and polarization plane of the excitation. This paves the way for a new class of ultimately thin polarization sensitive emitters to be used in future integrated quantum photonics devices.

Terahertz science and technology of carbon nanomaterials.

The diverse applications of terahertz (THz) radiation and its importance to fundamental science makes finding ways to generate, manipulate and detect THz radiation one of the key areas of modern applied physics. One approach is to utilize carbon nanomaterials, in particular, single-wall carbon nanotubes and graphene. Their novel optical and electronic properties offer much promise to the field of THz science and technology. This article describes the past, current, and future of THz science and technology of carbon nanotubes and graphene. We will review fundamental studies such as THz dynamic conductivity, THz nonlinearities and ultrafast carrier dynamics as well as THz applications such as THz sources, detectors, modulators, antennas and polarizers.

A French collaborative survey of 272 fetuses with 22q11.2 deletion: ultrasound findings, fetal autopsies and pregnancy outcomes.

OBJECTIVE: The 22q11.2 deletion (del22q11.2) is one of the most common microdeletions. We performed a collaborative, retrospective analysis in France of prenatal diagnoses and outcomes of fetuses carrying the del22q11.2. METHODS: A total of 272 fetuses were included. Data on prenatal diagnosis, ultrasound findings, pathological features, outcomes and inheritance were analyzed. RESULTS: The mean time of prenatal diagnosis was 25.6 ± 6 weeks of gestation. Most of the diagnoses (86.8%) were prompted by abnormal ultrasound findings [heart defects (HDs), in 83.8% of cases]. On fetal autopsy, HDs were again the most common disease feature, but thymus, kidney abnormalities and facial dysmorphism were also described. The deletion was inherited in 27% of cases. Termination of pregnancy (TOP) occurred in 68.9% of cases and did not appear to depend on the inheritance status. However, early diagnosis was associated with a higher TOP rate. CONCLUSION: This is the largest cohort of prenatal del22q11.2 diagnoses. As in postnatally diagnosed cases, HDs were the most frequently observed abnormalities. However, thymus and kidney abnormalities and polyhydramnios should also be screened for in the prenatal diagnosis of del22q11.2. Only the time of diagnosis appeared to be strongly associated with the pregnancy outcome: the earlier the diagnosis, the higher the TOP rate.

Optical valley separation in two-dimensional semimetals with tilted Dirac cones.

Quasiparticles emerging in crystalline materials can possess a binary flavor known as the valley quantum number which can be used as a basis to encode information in an emerging class of valleytronic devices. Here we show that two-dimensional semimetals with tilted Dirac cones in the electronic band structure exhibit spatial separation of carriers belonging to different valleys under illumination. In stark contrast to gapped Dirac materials this optovalleytronic phenomenon occurs in systems with intact inversion and time-reversal symmetry that host gapless Dirac cones in the band structure, thereby retaining the exceptional graphene-like transport properties. We thus demonstrate that optical valley separation is possible at arbitrarily low photon frequencies including the deep infrared and terahertz regimes with full gate tunability via Pauli blocking. As a specific example of our theory, we predict tunable valley separation in the proposed two-dimensional tilted Dirac cone semimetal 8-Pmmn borophene for incident infrared photons at room temperature. This work highlights the potential of two-dimensional tilted Dirac cone materials as a platform for tunable broadband optovalleytronic applications.

Quasi-exact solutions for guided modes in two-dimensional materials with tilted Dirac cones.

We show that if the solutions to the (2+1)-dimensional massless Dirac equation for a given one-dimensional (1D) potential are known, then they can be used to obtain the eigenvalues and eigenfunctions for the same potential, orientated at an arbitrary angle, in a 2D Dirac material possessing tilted, anisotropic Dirac cones. This simple set of transformations enables all the exact and quasi-exact solutions associated with 1D quantum wells in graphene to be applied to the confinement problem in tilted Dirac materials such as 8-Pmmn borophene. We also show that smooth electron waveguides in tilted Dirac materials can be used to manipulate the degree of valley polarization of quasiparticles travelling along a particular direction of the channel. We examine the particular case of the hyperbolic secant potential to model realistic top-gated structures for valleytronic applications.

Fourth case of cerebral, ocular, dental, auricular, skeletal syndrome (CODAS), description of new features and molecular analysis.

Cerebral, ocular, dental, auricular, skeletal syndrome (CODAS, OMIM 600373) is a very rare congenital malformation syndrome. This clinical entity is highly distinctive and associates mental retardation, cataract, enamel abnormalities, malformations of the helix, epiphyseal and vertebral malformations, and characteristic dysmorphic features. Since 1991, only three affected children have been reported. The etiology and pattern of inheritance of CODAS syndrome still remain unknown. We describe a new sporadic case presenting with all the characteristic features of CODAS syndrome associated with previously unreported malformations of the heart, larynx, and liver. All investigations such as karyotype, metabolic screening and array CGH were normal.

Publisher Correction: Two-dimensional Dirac particles in a Pöschl-Teller waveguide.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Simultaneous regression of Philadelphia chromosome and multiple nonrecurrent clonal chromosomal abnormalities with imatinib mesylate in a patient autografted 22 years before for chronic myelogenous leukemia.

A 31-year-old patient developed chronic myelogenous leukemia (CML) in November, 1983. In November 1984, following a diagnosis of acceleration, he received an autologous hemopoietic transplant after conditioning with cyclophosphamide and total body irradiation. The autologous marrow was purged with mafosfamide. Over 20 years, the patient remained in chronic phase of CML. Multiple nonrecurrent clonal chromosomal abnormalities appeared leading to a very complex karyotype, including among others involvement of chromosomes 1, 7, 9, 13, 19, and X. Fluorescent in situ hybridization showed that the two chromosomes 9 were involved. Acute myeloid crisis was diagnosed in February, 2004. Treatment with imatinib mesylate resulted within 6 months in a total disappearance of all chromosomal abnormalities with a complete cytogenetic and molecular response, which persists 3 years later. We question whether the ex vivo purging procedure with mafosfamide has favored the occurrence of these particular cytogenetic abnormalities (with no independent oncogenic potential) within the original leukemic stem cell pool. It remains unclear whether the autologous transplantation has indeed resulted into some prolongation of the duration of the chronic phase, which lasted for 20 years. At time of acute crisis, the dramatic response to imatinib mesylate leading to a complete cytogenetic and molecular response is noteworthy.

[Transient myeloproliferative disorder in a neonate without Down syndrome]. / Syndrome myélo-prolifératif transitoire chez un nouveau-né indemne de toute pathologie constitutionnelle.

We report a new case of transient myeloproliferative disorder (TMD) in a non Down syndrome neonate. The cytogenetic and molecular studies within from the blood blast cells identified a trisomy 21 and a partial deletion in exon 2 of the transcription factor GATA1. Spontaneous regression of the TMD was achieved at the age of 1 month as the clonal and molecular abnormalities. A survey by periodic cytological examinations of peripheral blood cells and GATA1 mutation analysis was instituted since three years and has not detected up to date acute leukaemia.

Bielectron vortices in two-dimensional Dirac semimetals.

Searching for new states of matter and unusual quasi-particles in emerging materials and especially low-dimensional systems is one of the major trends in contemporary condensed matter physics. Dirac materials, which host quasi-particles which are described by ultrarelativistic Dirac-like equations, are of a significant current interest from both a fundamental and applied physics perspective. Here we show that a pair of two-dimensional massless Dirac-Weyl fermions can form a bound state independently of the sign of the inter-particle interaction potential, as long as this potential decays at large distances faster than Kepler's inverse distance law. This leads to the emergence of a new type of energetically favorable quasiparticle: bielectron vortices, which are double-charged and reside at zero-energy. Their bosonic nature allows for condensation and may give rise to Majorana physics without invoking a superconductor. These novel quasi-particles arguably explain a range of poorly understood experiments in gated graphene structures at low doping.Two-dimensional Dirac semimetals are known to host fermionic excitations which can mimic physics usually found in ultrarelativistic quantum mechanics. Here, the authors unveil the existence of another type of quasiparticle, bielectron vortices, which are bosonic and may give rise to new types of condensates.

Two-dimensional Dirac particles in a Pöschl-Teller waveguide.

We obtain exact solutions to the two-dimensional (2D) Dirac equation for the one-dimensional Pöschl-Teller potential which contains an asymmetry term. The eigenfunctions are expressed in terms of Heun confluent functions, while the eigenvalues are determined via the solutions of a simple transcendental equation. For the symmetric case, the eigenfunctions of the supercritical states are expressed as spheroidal wave functions, and approximate analytical expressions are obtained for the corresponding eigenvalues. A universal condition for any square integrable symmetric potential is obtained for the minimum strength of the potential required to hold a bound state of zero energy. Applications for smooth electron waveguides in 2D Dirac-Weyl systems are discussed.

Localization of massless Dirac particles via spatial modulations of the Fermi velocity.

The electrons found in Dirac materials are notorious for being difficult to manipulate due to the Klein phenomenon and absence of backscattering. Here we investigate how spatial modulations of the Fermi velocity in two-dimensional Dirac materials can give rise to localization effects, with either full (zero-dimensional) confinement or partial (one-dimensional) confinement possible depending on the geometry of the velocity modulation. We present several exactly solvable models illustrating the nature of the bound states which arise, revealing how the gradient of the Fermi velocity is crucial for determining fundamental properties of the bound states such as the zero-point energy. We discuss the implications for guiding electronic waves in few-mode waveguides formed by Fermi velocity modulation.

Genes and premature ovarian failure.

Premature ovarian failure (POF) is an heterogeneous syndrome. Among genetic causes, X monosomy as in Turner syndrome or X deletions and translocations are known to be responsible for POF. The genes involved in ovarian function, located on the X chromosome are still unknown. On the other hand, autosomal abnormalities have been identified in POF patients such as mutations of the FSH gene, the LH and FSH receptor genes, chromosome 3q containing the blepharophimosis gene, the ATM gene (Ataxia-telangiectasia gene). Mutations in the AIRE gene (responsible for APECED syndrome) can involve ovarian insufficiency. It is likely that studies on the function of the protein AIRE might improve our knowledge on follicular development. Furthermore, different mouse models of ovarian failure such as mouse lacking connexins or mice lacking GDF9 (growth derived factor 9), might increase our knowledge of ovarian failure. In the future, a better knowledge of the cellular and biochemical components involved in folliculogenesis and apoptosis should elucidate the mechanisms of POF.

Pierre Robin sequence and interstitial deletion 2q32.3-q33.2.

Pierre Robin sequence (PRS) consists of the nonrandom association of micrognathia, cleft palate (CP), and glossoptosis. It also includes respiratory and feeding difficulties that appear to be neurogenic rather than mechanical in causation. Genetic determinants are thought to underlie this functional and morphological entity, based on the existence of Mendelian syndromes with PRS, and the rare observations of familial nonsyndromic PRS, in which some of the affected individuals have isolated CP. We report the association of PRS with deletion 2q32.3-q33.2 due to an unbalanced reciprocal translocation 46,XX, t(2;21), del 2(q32.3q33.2), and we refine the deletion interval with regard to YAC probes and polymorphic DNA markers. The deletion was shown to be flanked by D2S369 (telomeric) and D2S315 (centromeric), thus it maps to a recently determined chromosomal region known to be nonrandomly associated with CP. This observation supports the hypothesis for the genetic bases of nonsyndromic PRS, strengthens its possible genetic association with isolated CP, and provides a candidate PRS locus, in chromosomal region 2q32.3-q33.2.

Unrelated mismatched cord blood transplantation in patients with hematological malignancies: a single institution experience.

We report on six cases of unrelated UCB transplant in adult patients with hematological malignancies: three chronic myelocytic leukemias and three acute leukemias. Their median age and body weight were respectively: 28 years (range 15.5-40) and 55.5 kg (range 46-90). The cord blood units were from the New York Blood Center. The median number of nuclear cells provided, evaluated before thawing, was 2.1 x 10(7)/kg (range 1 x 10(7)/kg-4.7 x 10(7)/kg). The degree of HLA disparity was 1/6: two patients, 2/6: three patients, 3/6: one patient. The patients received a pretransplant regimen including total body irradiation. They were given graft-versus-host disease prophylaxis which consisted of cyclosporin A and corticosteroids. They were all given a combination of G-CSF and erythropoietin. The median time of white blood cell and platelet reconstitution were respectively 24 days (range 12-43) and 60 days (range 23-90). All the patients had a full chimerism. A grade I acute GVHD was observed in four patients and two patients do not have any GVHD. No chronic GVHD has been observed yet. Three patients died from toxicity. Three patients are alive and well in complete remission at 2 years, 1 year and 11 months post-graft.

Karyotypes of 1142 couples with recurrent abortion.

Cytogenetic analysis was performed on 1142 couples with recurrent pregnancy loss. The frequency of major chromosomal abnormalities per couple was 4.8%. Among 771 couples who had only abortions, the rate of rearrangement did not correlate with the number of abortions. The highest incidence of cytogenetic abnormalities (6.6%) was found in 256 couples with abortion and a normal child. With regard to pregnancy outcome, no unbalanced fetal karyotype was found in prenatal diagnoses, and 40 normal children were born. The risk of unbalanced fetal karyotype is therefore low, but probably high enough for these couples to be offered the possibility of a prenatal diagnosis.

Semen analysis in subfertile balanced-translocation carriers.

The spermograms of 19 subfertile translocation carriers were analyzed. Most of these men had moderate oligo-/astheno-/teratospermia. The results were widely spread, and some reached normal values, suggesting that autosomal rearrangement of the karyotype does not lead to severe oligospermia or azoospermia as do sex chromosome aberrations. No statistically significant differences in sperm count, motility, or morphology were found when semen analysis results of subfertile balanced-translocation carriers were compared with those of subfertile men with normal karyotypes. Since semen analysis alone is insufficient to allow prediction of an autosomal rearrangement of the karyotype, chromosome analysis should become a part of the routine investigation of subfertile men. The association between translocation heterozygosity and reduced fertility in men cannot be easily explained. The possible reasons underlying impaired spermatogenesis in some translocation carriers are discussed in relation to meiotic findings in animals.

A new case of a severe clinical phenotype of the cat-eye syndrome.

A new case of severe clinical phenotype of the cat-eye syndrome: We report on a female infant with severe clinical phenotype of Cat-Eye Syndrome (CES). At birth, she had respiratory distress and marked hypotonia. Physical examination showed major craniofacial anomalies including microcephaly, bilateral total absence of the external ears, hypertelorism, bilateral ocular coloboma of iris and micrognathia. In addition, she had anal stenosis, a patent ductus arteriosus and intra- and extra- hepatic biliary atresia. She deteriorated with the development of bradycardia. She died at age one month of cardiac failure. Cytogenetic analysis of the proband showed an extra de novo small bisatelllited marker chromosome in all cells examined. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) identified the marker as a CES chromosome. Thus, the patient's karyotype was: 47, XX, +idic(22)(pter-->q11.2 ::q11.2-->pter). The duplication breakpoints giving rise to the CES chromosome were distal to the DiGeorge Syndrome (DGS) locus 22q11.2. The marker could be classed as a type 11 symmetrical (10). According to a recent review of CES literature (1) only 41 % of the CES patients have the combination of iris coloboma, anal anomalies and preauricular anomalies. Almost 60% are hard to recognize by their phenotype alone. Only twelve patients showed a severe clinical phenotype leading to the death of the child. This phenotypic variability increases the difficulties of genetic counseling.

[Balanced translocations with abnormal phenotype (author's transl)]. / Translocations apparemment équilibrées à phénotype anormal.

Four cases of balanced translocations with phenotype abnormalities are reported. Three of them are reciprocal translocation, one is a Robertsonnian translocation. The consequences of the phenomene on genetic counselling and prenatal diagnosis are discussed.

[Fetal karyotyping of fetal blood obtained from the umbilical vein using ultrasound]. / Caryotype foetal sur le sang foetal prélevé dans la veine ombilicale sous échographie.

The fetal karyotype was established during the second or third trimester of 18 at risk pregnancies after fetal blood sampling by direct puncture of the umbilical vein guided by real time ultrasound. Two karyotypes were abnormal. This rapid technique for karyotyping allows the obstetrician to decide early how the pregnancy should be conducted.