Growth and characterization of ZnTe films grown on GaAs, InAs, GaSb, and ZnTe

We report the successful growth of ZnTe on nearly lattice-matched III-V buffer layers of InAs (0.75%), GaSb (0.15%), and on GaAs and ZnTe by molecular beam epitaxy. In situ reflection high-energy electron diffraction measurements showed the characteristic streak patterns indicative of two-dimensional growth. Photoluminescence measurements on these films show strong and sharp features near the band edge with no detectable luminescence at longer wavelengths. The integrated photoluminescence intensity from the ZnTe layers increased with better lattice match to the buffer layer. The ZnTe epilayers grown on high-purity ZnTe substrates exhibited stronger luminescence than the substrates. We observe narrow luminescence linewidths (full width at half maximum ~ 1–2 Å) indicative of uniform high quality growth. Secondary-ion mass spectroscopy and electron microprobe measurements, however, reveal substantial outdiffusion of Ga and In for growths on the III-V buffer layers

Application of nanotags and nanobodies for live cell single-molecule imaging of the Z-ring in Escherichia coli

Understanding where proteins are localized in a bacterial cell is essential for understanding their function and regulation. This is particularly important for proteins that are involved in cell division, which localize at the division septum and assemble into highly regulated complexes. Current knowledge of these complexes has been greatly facilitated by super-resolution imaging using fluorescent protein fusions. Herein, we demonstrate with FtsZ that single-molecule PALM images can be obtained in-vivo using a genetically fused nanotag (ALFA), and a corresponding nanobody fused to mEos3.2. The methodology presented is applicable to other bacterial proteins.journal articl

Cell cycle regulators p27 and pRb in lymphomas – correlation with histology and proliferative activity

The cell cycle is a complex event in which multiple regulator-proteins participate. The G 1/S checkpoint of the cell cycle is controlled by pRb protein, which functions in its hypophosphorylated form as a negative regulator of growth. p27 (Kip1), a member of CIP/KIP family of cyclin inhibitory proteins, participates in inhibition of forming complexes that allow pRb to phosphorylate and lead the cell into mitosis. The expression of these important cell cycle regulator proteins was studied in a total of 96 non-Hodgkin’s lymphoma (NHL) samples, which were classified according to the REAL classification. The expression of p27, pRb and the cell proliferation marker Ki-67 (MIB-1) was evaluated in lymphomas using immunohistochemistry. This study showed that there were coordinate changes in the expression of p27 and pRb in NHL. When compared to low-grade lymphomas, high-grade lymphomas showed significantly reduced expression of p27 and inversely pRb expression was increased (P < 0.001). Increase in expression of Ki-67 was parallel with pRb expression, and was mainly seen in cells that lacked p27 expression (P < 0.0001). This study suggests that changes in the control of the cell cycle closely relate to the pathobiology of NHL. © 2000 Cancer Research Campaig

City Avoidance in the Early Phase of Psychosis: A Neglected Domain of Assessment and a Potential Target for Recovery Strategies.

Background: A considerable amount of research has explored the link between living in an urban environment during childhood and the increased risk to develop psychosis. However, the urban milieu is more than a risk factor as it is also a place for socialization and enrichment. The aims of the current study were to explore, in a large sample of early psychosis (EP) patients, their pattern of use of the city, their perception when exposed to various critical stressors, and their sensitivity to diverse forms of stimuli. Methods: We sent a questionnaire (based on previous work conducted in a group of patients, including video-recorded walk-along in the city and a literature review) to 305 EP patients and to 220 medical students. Results: Response rate in patients was low (38%). City avoidance and negative perceptions towards the urban environment increased in patients after onset of psychosis. Patients' tendency to avoid city center correlates with both problematic social interactions and stimuli perceived as unpleasant. Patients seemed less likely to enjoy urban spaces considered as relaxing, suggesting a lower capacity to benefit from positive aspects of this environment. Conclusions: The development of psychosis influences the way EP patients perceive the city and their capacity to feel at ease in the urban environment, leading to a high rate of city avoidance. Considering the possible influence of city avoidance on social relations and the recovery process, the development of strategies to help patients in this regard may have a significant effect on their recovery process

An OregonGreen488-labelled d-amino acid for visualizing peptidoglycan by super-resolution STED nanoscopy

Fluorescent d-amino acids (FDAAs) are molecular probes that are widely used for labelling the peptidoglycan layer of bacteria. When added to growing cells they are incorporated into the stem peptide by a transpeptidase reaction, allowing the timing and localization of peptidoglycan synthesis to be determined by fluorescence microscopy. Herein we describe the chemical synthesis of an OregonGreen488-labelled FDAA (OGDA). We also demonstrate that OGDA can be efficiently incorporated into the PG of Gram-positive and some Gram-negative bacteria, and imaged by super-resolution stimulated emission depletion (STED) nanoscopy at a resolution well below 100 nm

Angular emission distribution of O 1s photoelectrons of uniaxially oriented methanol

The angular distribution of O 1s photoelectrons emitted from uniaxially oriented methanol is studied experimentally and theoretically. We employed circularly polarized photons of an energy of hν = 550 eV for our investigations. We measured the three-dimensional photoelectron angular distributions of methanol, with the CH3–OH axis oriented in the polarization plane, by means of cold target recoil ion momentum spectroscopy. The experimental results are interpreted by single active electron calculations performed with the single center method. A comparative theoretical study of the respective molecular-frame angular distributions of O 1s photoelectrons of CO, performed for the same photoelectron kinetic energy and for a set of different internuclear distances, allows for disentangling the role of internuclear distance and the hydrogen atoms of methanol as compared to carbon monoxide

Roadmaps to Utopia: Tales of the Smart City

Notions of the Smart City are pervasive in urban development discourses. Various frameworks for the development of smart cities, often conceptualized as roadmaps, make a number of implicit claims about how smart city projects proceed but the legitimacy of those claims is unclear. This paper begins to address this gap in knowledge. We explore the development of a smart transport application, MotionMap, in the context of a £16M smart city programme taking place in Milton Keynes, UK. We examine how the idealized smart city narrative was locally inflected, and discuss the differences between the narrative and the processes and outcomes observed in Milton Keynes. The research shows that the vision of data-driven efficiency outlined in the roadmaps is not universally compelling, and that different approaches to the sensing and optimization of urban flows have potential for empowering or disempowering different actors. Roadmaps tend to emphasize the importance of delivering quick practical results. However, the benefits observed in Milton Keynes did not come from quick technical fixes but from a smart city narrative that reinforced existing city branding, mobilizing a growing network of actors towards the development of a smart region. Further research is needed to investigate this and other smart city developments, the significance of different smart city narratives, and how power relationships are reinforced and constructed through them

Borrelia burgdorferi Infection in Biglycan Knockout Mice

Background: Borrelia burgdorferi sensu lato spirochetes (Borrelia) causing Lyme borreliosis are able to disseminate from the initial entry site to distant organs in the host. Outer-surface adhesins are crucial in the bacterial dissemination and adhesion to various tissues. Two well-characterized Borrelia adhesins, decorin-binding proteins A and B, have been shown to bind to 2 host receptors, decorin and biglycan. However, the role of biglycan in Borrelia infection has not been characterized in vivo.Methods: We infected biglycan knockout (KO) and wild-type (WT) C3H mice with strains representing 3 Borrelia genospecies, Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii. The infection was monitored by measuring joint swelling, Borrelia culture, polymerase chain reaction analysis, and serologic analysis. The host immune responses were analyzed by histological scoring of the inflammation in tissues and by cytokine profiling.Results: B. burgdorferi sensu stricto and B. garinii established long-term infection in mice of both genotypes, while B. afzelii failed to disseminate in KO mice. Further, the B. burgdorferi sensu stricto–infected KO mice had persistent inflammation in the joints.Conclusions: The dissemination and tissue colonization of Borrelia and the inflammatory response of the host differ in a mouse biglycan expression– and Borrelia genospecies–dependent manner.</p