Realizing lateral wrap-gated nanowire FETs: Controlling gate length with chemistry rather than lithography

An important consideration in miniaturizing transistors is maximizing the coupling between the gate and the semiconductor channel. A nanowire with a coaxial metal gate provides optimal gate-channel coupling, but has only been realized for vertically oriented nanowire transistors. We report a method for producing laterally oriented wrap-gated nanowire field-effect transistors that provides exquisite control over the gate length via a single wet etch step, eliminating the need for additional lithography beyond that required to define the source/drain contacts and gate lead. It allows the contacts and nanowire segments extending beyond the wrap-gate to be controlled independently by biasing the doped substrate, significantly improving the sub-threshold electrical characteristics. Our devices provide stronger, more symmetric gating of the nanowire, operate at temperatures between 300 to 4 Kelvin, and offer new opportunities in applications ranging from studies of one-dimensional quantum transport through to chemical and biological sensing.Comment: 16 pages, 5 figures. Submitted version, published version available at http://http://pubs.acs.org/journal/nalef

Catálogo de los objetos que presentan Noruega y Suecia a la Exposición Histórico-Americana de Madrid.

Copia digital. España : Ministerio de Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 2021Tit. en cub.: Catálogo especial de Suecia y Norueg

Open chest and pericardium facilitate transpulmonary passage of venous air emboli

Background: Transpulmonary passage of air emboli can lead to fatal brain- and myocardial infarctions. We studied whether pigs with open chest and pericardium had a greater transpulmonary passage of venous air emboli than pigs with closed thorax. Methods: We allocated pigs with verified closed foramen ovale to venous air infusion with either open chest with sternotomy and opening of the pleura and pericardium (n = 8) or closed thorax (n = 16). All pigs received a five-hour intravenous infusion of ambient air, starting at 4-6 mL/kg/h and increased by 2 mL/kg/h each hour. We assessed transpulmonary air passage by transesophageal M-mode echocardiography and present the results as median with inter-quartile range (IQR). Results: Transpulmonary air passage occurred in all pigs with open chest and pericardium and in nine pigs with closed thorax (56%). Compared to pigs with closed thorax, pigs with open chest and pericardium had a shorter to air passage (10 minutes (5-16) vs. 120 minutes (44-212), P < .0001), a smaller volume of infused air at the time of transpulmonary passage (12 mL (10-23) vs.170 mL (107-494), P < .0001), shorter time to death (122 minutes (48-185) vs 263 minutes (248-300, P = .0005) and a smaller volume of infused air at the time of death (264 mL (53-466) vs 727 mL (564-968), P = .001). In pigs with open chest and, infused air and time to death correlated strongly (r = 0.95, P = .001). Conclusion: Open chest and pericardium facilitated the transpulmonary passage of intravenously infused air in pigs

Rescue the child or treat the adult? Understandings among professionals in dual treatment of substance-use disorders and parenting

Aims: Dual treatment of parents with substance-use disorders (SUD) is an approach which aims to meet the needs of both SUD patients and their children. Whereas the parents need to learn to live without substances, the children need a predictable and structured environment with parents who are sensitive and psychologically available. In this study we explore the possibilities and challenges of this joint approach from the perspectives of professionals employed in an in-patient facility for families with parental SUD. Methods: A qualitative design was used comprising three focus-group interviews with 15 professionals: two groups with ward staff and one with therapists, all working at a family ward for parents with SUD and their children. Data were analysed using thematic analysis. Results: Professionals faced difficulties combining the needs of parents and children and seemed to choose to prioritise either the adult with SUD or the wellbeing of the child. However, some professionals described what might be a third and alternative solution by supporting the mothers in everyday life, routines, and care, through exploring present moment situations. This approach seemed to help parents become more conscious of the child, their interaction with the child, and their own feelings. Professionals described working at the family ward as emotionally challenging. Conclusion: Combining treatment of parental SUD, interventions to improve parenting roles and practice, and at the same time focusing on the developmental needs of children, is experienced as a complex and demanding task. Different priorities and treatment aims may enhance tensions between professionals. Even though professionals experience in-patient dual treatment as challenging, they believe this approach facilitates positive development in substance dependent parents and their children.publishedVersio

Bacterial control of host gene expression through RNA polymerase II

The normal flora furnishes the host with ecological barriers that prevent pathogen attack while maintaining tissue homeostasis. Urinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation in which some patients infected with Escherichia coil develop acute pyelonephritis, while other patients with bacteriuria exhibit an asymptomatic carrier state similar to bacterial commensalism. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease-associated responses in the host. Here, we identify a new mechanism of bacterial adaptation through broad suppression of RNA polymerase II-dependent (Pol II-dependent) host gene expression. Over 60% of all genes were suppressed 24 hours after human inoculation with the prototype asymptomatic bacteriuria (ABU) strain E. coil 83972, and inhibition was verified by infection of human cells. Specific repressors and activators of Pol II-dependent transcription were modified, Pol II phosphorylation was inhibited, and pathogen-specific signaling was suppressed in cell lines and inoculated patients. An increased frequency of strains inhibiting Pol II was epidemiologically verified in ABU and fecal strains compared with acute pyelonephritis, and a Pol II antagonist suppressed the disease-associated host response. These results suggest that by manipulating host gene expression, ABU strains promote tissue integrity while inhibiting pathology. Such bacterial modulation of host gene expression may be essential to sustain asymptomatic bacterial carriage by ensuring that potentially destructive immune activation will not occur

Multi-parametric assessment of the anti-angiogenic effects of liposomal glucocorticoids

Inflammation plays a prominent role in tumor growth. Anti-inflammatory drugs have therefore been proposed as anti-cancer therapeutics. In this study, we determined the anti-angiogenic activity of a single dose of liposomal prednisolone phosphate (PLP-L), by monitoring tumor vascular function and viability over a period of one week. C57BL/6 mice were inoculated subcutaneously with B16F10 melanoma cells. Six animals were PLP-L-treated and six served as control. Tumor tissue and vascular function were probed using MRI before and at three timepoints after treatment. DCE-MRI was used to determine Ktrans, ve, time-to-peak, initial slope and the fraction of non-enhancing pixels, complemented with immunohistochemistry. The apparent diffusion coefficient (ADC), T2 and tumor size were assessed with MRI as well. PLP-L treatment resulted in smaller tumors and caused a significant drop in Ktrans 48 h post-treatment, which was maintained until one week after drug administration. However, this effect was not sufficient to significantly distinguish treated from non-treated animals. The therapy did not affect tumor tissue viability but did prevent the ADC decrease observed in the control group. No evidence for PLP-L-induced tumor vessel normalization was found on histology. Treatment with PLP-L altered tumor vascular function. This effect did not fully explain the tumor growth inhibition, suggesting a broader spectrum of PLP-L activities

Erik den Rødes saga : eller, Sagaen om Vinland /

Mode of access: Internet

Designed Quasi-1D Potential Structures Realized in Compositionally Graded InAs1-xPx Nanowires.

III-V semiconductor heterostructures are important components of many solid-state optoelectronic devices, but the ability to control and tune the electrical and optical properties of these structures in conventional device geometries is fundamentally limited by the bulk dimensionality and the inability to accommodate lattice-mismatched material combinations. Here we demonstrate how semiconductor nanowires may enable the creation of arbitrarily shaped one-dimensional potential structures for new types of designed device functionality. We describe the controlled growth of stepwise compositionally graded InAs1-xPx heterostructures defined along the axes of InAs nanowires, and we show that nanowires with sawtooth-shaped composition profiles behave as near-ideal unipolar diodes with ratchet-like rectification of the electron transport through the nanowires, in excellent agreement with simulations. This new type of designed quasi-1D potential structure represents a significant advance in band gap engineering and may enable fundamental studies of low-dimensional hot-carrier dynamics, in addition to constituting a platform for implementing novel electronic and optoelectronic device concepts

Transparently Wrap-Gated Semiconductor Nanowire Arrays For Studies Of Gate-Controlled Photoluminescence

We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure