Ballistic InSb Nanowires and Networks via Metal-Sown Selective Area Growth

Selective area growth is a promising technique to realize semiconductor-superconductor hybrid nanowire networks, potentially hosting topologically protected Majorana-based qubits. In some cases, however, such as the molecular beam epitaxy of InSb on InP or GaAs substrates, nucleation and selective growth conditions do not necessarily overlap. To overcome this challenge, we propose a metal-sown selective area growth (MS SAG) technique, which allows decoupling selective deposition and nucleation growth conditions by temporarily isolating these stages. It consists of three steps: (i) selective deposition of In droplets only inside the mask openings at relatively high temperatures favoring selectivity, (ii) nucleation of InSb under Sb flux from In droplets, which act as a reservoir of group III adatoms, done at relatively low temperatures, favoring nucleation of InSb, and (iii) homoepitaxy of InSb on top of the formed nucleation layer under a simultaneous supply of In and Sb fluxes at conditions favoring selectivity and high crystal quality. We demonstrate that complex InSb nanowire networks of high crystal and electrical quality can be achieved this way. We extract mobility values of 10※000-25※000 cm V s consistently from field-effect and Hall mobility measurements across single nanowire segments as well as wires with junctions. Moreover, we demonstrate ballistic transport in a 440 nm long channel in a single nanowire under a magnetic field below 1 T. We also extract a phase-coherent length of ∼8 μm at 50 mK in mesoscopic rings

Schizophrenia Spectrum Disorders in Later Life: Prevalence and Distribution of Age at Onset and Sex in a Dutch Catchment Area

Objectives: The prevalence of schizophrenia in later life is affected by both outflow of early onset patients, due to recovery and excess mortality, and inflow of patients with a later age at onset, making it likely that characteristics of older patients differ markedly from younger patients. We assessed the prevalence of schizophrenia and spectrum disorders and their distribution according to age at onset and sex in an elderly population. Design: Case register study. Setting and Participants: All patients age 60 years and older, in contact with the Mental Health Organization in a psychiatric catchment area in Amsterdam (the Netherlands), diagnosed with schizophrenia, schizoaffective disorder, or delusional disorder. Measurements: One-year prevalence estimates, including rates according to age group, age at onset, and sex. In addition, we determined the effect of using different criteria for age at onset. Results: The one-year prevalence of all disorders was 0.71%, subdivided in 0.55% for schizophrenia, 0.14% for schizoaffective disorder, and 0.03% for delusional disorder. The one-year prevalence of early-onset schizophrenia was 0.35%, of late-onset schizophrenia 0.14%, and of very-late-onset schizophrenia-like psychosis 0.05%. Variation of onset criterion affected the proportion of early-onset versus late-onset schizophrenia patients stronger in women than in men. Women outnumbered men markedly in the prevalence estimates for most diagnostic subgroups, including early-onset schizophrenia. Conclusions: We found the prevalence of schizophrenia among older persons to be well within the range reported for younger populations. The considerable proportion with a later age at onset and the strong female preponderance are distinguishing characteristics of older patients with clinical implications. (Am J Geriatr Psychiatry 2012; 20: 18-28

A comparison of depressive symptom profiles between current major depressive disorder and schizophrenia spectrum disorder

Introduction: Depressive symptoms are highly prevalent and clinically relevant in schizophrenia spectrum disorder (SSD) patients. So far, little is known about to what extent the depressive symptom profile in SSD is comparable to that seen in major depressive disorder (MDD). Methods: Data were derived from the Genetic Risk and Outcome of Psychosis study (GROUP) and the Netherlands Study of Depression and Anxiety (NESDA). We examined differences in severity of depressive symptom profiles and distribution of mood/cognition and somatic/vegetative depressive symptoms using the Quick Inventory of Depressive Symptomatology - Self Report (QIDS-SR) within SSD patients (n = 449), MDD patients (n = 816) and healthy controls (n = 417), aged 18 to 50. Within SSD, associations between depression severity and clinical and demographic data were examined. Results: 60.4% of SSD patients showed substantial depressive symptomatology (QIDS-SR >= 6). The difference in mood/cognition symptoms between SSD and MDD was larger (higher symptoms in MDD, effect size = 1.13), than the differences in somatic/vegetative symptoms (effect size 0.74). In patients with SSD, multivariable regression analyses showed that lower social functioning, male gender, use of benzodiazepine and more severe positive symptoms were associated with higher overall depressive symptomatology. The use of antipsychotics or anti-depressants was associated with more somatic/vegetative symptoms. Conclusion: More than half of SSD patients have considerable depressive symptomatology, with a relative preponderance of somatic/vegetative symptoms compared to the profile seen in MDD. Future research could explore whether depressive symptom profile in SSD may also be associated with biological dysregulations like in MDD

Ballistic InSb Nanowires and Networks via Metal-Sown Selective Area Growth

Selective area growth is a promising technique to realize semiconductor-superconductor hybrid nanowire networks, potentially hosting topologically protected Majorana-based qubits. In some cases, however, such as the molecular beam epitaxy of InSb on InP or GaAs substrates, nucleation and selective growth conditions do not necessarily overlap. To overcome this challenge, we propose a metal-sown selective area growth (MS SAG) technique, which allows decoupling selective deposition and nucleation growth conditions by temporarily isolating these stages. It consists of three steps: (i) selective deposition of In droplets only inside the mask openings at relatively high temperatures favoring selectivity, (ii) nucleation of InSb under Sb flux from In droplets, which act as a reservoir of group III adatoms, done at relatively low temperatures, favoring nucleation of InSb, and (iii) homoepitaxy of InSb on top of the formed nucleation layer under a simultaneous supply of In and Sb fluxes at conditions favoring selectivity and high crystal quality. We demonstrate that complex InSb nanowire networks of high crystal and electrical quality can be achieved this way. We extract mobility values of 10※000-25※000 cm V s consistently from field-effect and Hall mobility measurements across single nanowire segments as well as wires with junctions. Moreover, we demonstrate ballistic transport in a 440 nm long channel in a single nanowire under a magnetic field below 1 T. We also extract a phase-coherent length of ∼8 μm at 50 mK in mesoscopic rings