Controlled generation of luminescent centers in hexagonal boron nitride by irradiation engineering.

Luminescent centers in the two-dimensional material hexagonal boron nitride have the potential to enable quantum applications at room temperature. To be used for applications, it is crucial to generate these centers in a controlled manner and to identify their microscopic nature. Here, we present a method inspired by irradiation engineering with oxygen atoms. We systematically explore the influence of the kinetic energy and the irradiation fluence on the generation of luminescent centers. We find modifications of their density for both parameters, while a fivefold enhancement is observed with increasing fluence. Molecular dynamics simulations clarify the generation mechanism of these centers and their microscopic nature. We infer that VNCB and [Formula: see text] are the most likely centers formed. Ab initio calculations of their optical properties show excellent agreement with our experiments. Our methodology generates quantum emitters in a controlled manner and provides insights into their microscopic nature.

Meningococcal disease and future drug targets.

Neisseria meningitidis (N. meningitidis) causes sepsis, epidemic meningitis, and sometimes also meningoencephalitis. Despite early antibiotic treatment, mortality and morbidity remain significant. We present recent studies on meningococcal disease with focus on the pathophysiology caused by bacterial virulence factors and the host immune responses. The bacterial outer membrane lipopolysaccharide and non-lipopolysaccharide components are related to meningococcal adhesion and invasion, while the host immune reactions propagate inflammation and neurodegeneration. Hence, bacterium-host interactions are key determinants of the clinical course and risk of fatal outcome. Accordingly, successful treatment of severe meningococcal disease requires not only antibiotics but also adjuvants targeting the released endotoxins and the host immune/inflammatory responses. This review highlights the most recent data and current knowledge on molecular mechanisms of meningococcal disease and explains how host immune responses ultimately may aggravate neuropathology and the clinical prognosis. Within this context, particular importance is paid to the endotoxic components that provide potential drug targets for novel neuroprotective adjuvants, which are needed in order to improve the clinical management of meningoencephalitis and patient prognosis.

Direct measurement of electrical conductance through a self-assembled molecular layer.

The self-assembly of organic molecules on surfaces is a promising approach for the development of nanoelectronic devices. Although a variety of strategies have been used to establish stable links between molecules, little is known about the electrical conductance of these links. Extended electronic states, a prerequisite for good conductance, have been observed for molecules adsorbed on metal surfaces. However, direct conductance measurements through a single layer of molecules are only possible if the molecules are adsorbed on a poorly conducting substrate. Here we use a nanoscale four-point probe to measure the conductivity of a self-assembled layer of cobalt phthalocyanine on a silver-terminated silicon surface as a function of thickness. For low thicknesses, the cobalt phthalocyanine molecules lie flat on the substrate, and their main effect is to reduce the conductivity of the substrate. At higher thicknesses, the cobalt phthalocyanine molecules stand up to form stacks and begin to conduct. These results connect the electronic structure and orientation of molecular monolayer and few-layer systems to their transport properties, and should aid in the rational design of future devices.

Ultrasound and MRI before and after radical hysterectomy: does the operation affect the pelvic floor muscles?

PURPOSE: To evaluate pelvic floor muscles and bladder neck mobility before and after radical hysterectomy for cervical cancer with magnetic resonance imaging (MRI) and ultrasound. METHODS: A prospective follow-up study of 22 patients studied with MRI and ultrasound preoperatively, three and 12 months after radical hysterectomy was carried out. RESULTS: Bladder neck mobility was decreased three months postoperatively, but one year after the operation, it had almost attained the preoperative level. The size of the pelvic floor muscles was reduced three months after the operation, but one year postoperatively, muscle size had almost returned to the preoperative level. Age and number of deliveries affected the starting point in muscle size and the mobility of the bladder neck, but the development was identical in all the women. CONCLUSIONS: We showed that pelvic floor muscle size and mobility of the bladder neck were reduced three months after radical hysterectomy, and that they regenerated to a level only slightly below the preoperative level one year later.