Life cycle cost considerations in project appraisals of collision-free roads

In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.     

Image analysis in nonlinear microscopy

The ability to automatically extract quantitative data from nonlinear microscopy images is here explored, taking nonlinear and coherent effects into account. Objects of different degrees of complexity were investigated: theoretical images of spherical objects, experimentally collected coherent anti-Stokes Raman scattering images of polystyrene spheres in background-generating agar, well-separated lipid droplets in living yeast cells, and conglomerations of lipid droplets in living C. elegans nematodes. The in linear microscopy useful measure of full width at half-maximum (FWHM) was shown to provide inadequate measures of object size due to the nonlinear density dependence of the signal. Instead, the capability of four state-of-the-art image analysis algorithms was evaluated. Among these, local thresholding was found to be the widest applicable segmentation algorithm.     

Guiding the self-assembly of a second-generation polyphenylene dendrimer into well-defined patterns

A second-generation polyphenylene dendrimer 1 is shown to self-assemble into nanofibers. To guide the formation of the dendrimer fibers into well-defined patterns, 1H,1H,2H,2H-perfluorodecyltrichlorosilane is grafted in the gas phase onto a silicon substrate. De-wetting of the solution on the nanopatterned surface results in the formation of a nanostructured template, into which fiber growth subsequently occurs under the constraints set by the de-wetted morphology.     

Bolt-anchored, steel-fibre-reinforced shotcrete linings

This study describes rock reinforcement through the use of reinforced shotcrete in structural interaction with rock bolts. The intention of the investigation was to increase the knowledge of steel-fibre-reinforced shotcrete and the way in which bolt anchorage in shotcrete is designed. The researcher performed 22 large-scale laboratory tests on bolt-anchored, reinforced shotcrete lays, 19 of which were reinforced with Bekaert steel fibres, 2 with cold-tensioned reinforcement mesh, and 1 with an annealed mesh. Fibre content, fibre length and anchorage of the bolt in the shotcrete varied in the tests. For each large-scale test, adhesion tests on the rock-shotcrete interface were performed, as well as strength on sawn-out shotcrete cubes and beams both with and without fibres. The concrete mass was tested using cast cubes. Four large-scale tests on extremely thin fibre-reinforced linings without bolt anchorage also were performed. Two specimens contained steel fibres, and two contained glass fibres. Details also are provided of shear tests on split steel-fibre-reinforced test specimens on a small scale. The paper concludes with a discussion of the test results.     

Race to the top in traffic calming

We study the competition of two suburbs facing transit traffic flows. The suburbs are substitutes for transit traffic. In the absence of toll measures, the symmetric Nash equilibrium with two local governments leads to a race to the top in traffic calming measures that increases the cost of travel. The Nash equilibrium is compared to two types of centralized decisions: the symmetric solution and the asymmetric solution. The asymmetric solution that concentrates all transit traffic in one suburb is better but can only be realized if the authority over the local roads is transferred to the central authority.     

Infection of Brain Pericytes Underlying Neuropathology of COVID-19 Patients

A wide range of neurological manifestations have been associated with the development of COVID-19 following SARS-CoV-2 infection. However, the etiology of the neurological symptomatology is still largely unexplored. Here, we used state-of-the-art multiplexed immunostaining of human brains (n = 6 COVID-19, median age = 69.5 years; n = 7 control, median age = 68 years) and demonstrated that expression of the SARS-CoV-2 receptor ACE2 is restricted to a subset of neurovascular pericytes. Strikingly, neurological symptoms were exclusive to, and ubiquitous in, patients that exhibited moderate to high ACE2 expression in perivascular cells. Viral dsRNA was identified in the vascular wall and paralleled by perivascular inflammation, as signified by T cell and macrophage infiltration. Furthermore, fibrinogen leakage indicated compromised integrity of the blood–brain barrier. Notably, cerebrospinal fluid from additional 16 individuals (n = 8 COVID-19, median age = 67 years; n = 8 control, median age = 69.5 years) exhibited significantly lower levels of the pericyte marker PDGFRβ in SARS-CoV-2-infected cases, indicative of disrupted pericyte homeostasis. We conclude that pericyte infection by SARS-CoV-2 underlies virus entry into the privileged central nervous system space, as well as neurological symptomatology due to perivascular inflammation and a locally compromised blood–brain barrier.     

Repeated and Interrupted Resistance Exercise Induces the Desensitization and Re-Sensitization of mTOR-Related Signaling in Human Skeletal Muscle Fibers

The acute resistance exercise (RE)-induced phosphorylation of mTOR-related signaling proteins in skeletal muscle can be blunted after repeated RE. The time frame in which the phosphorylation (_p) of mTOR^S2448, p70S6k^T421/S424, and rpS6^S235/236 will be reduced during an RE training period in humans and whether progressive (PR) loading can counteract such a decline has not been described. (1) To enclose the time frame in which _pmTOR^S2448, _prpS6^S235/236, and _pp70S6k^T421/S424 are acutely reduced after RE occurs during repeated RE. (2) To test whether PR will prevent that reduction compared to constant loading (CO) and (3) whether 10 days without RE may re-increase blunted signaling. Fourteen healthy males (24 ± 2.8 yrs.; 1.83 ± 0.1 cm; 79.3 ± 8.5 kg) were subjected to RE with either PR (n = 8) or CO (n = 6) loading. Subjects performed RE thrice per week, conducting three sets with 10–12 repetitions on a leg press and leg extension machine. Muscle biopsies were collected at rest (T0), 45 min after the first (T1), seventh (T7), 13th (T13), and 14th (X-T14) RE session. No differences were found between PR and CO for any parameter. Thus, the groups were combined, and the results show the merged values. _prpS6^S235/236 and _pp70s6k^T421/S424 were increased at T1, but were already reduced at T7 and up to T13 compared to T1. Ten days without RE re-increased _prpS6^S235/236 and _pp70S6k^T421/S424 at X-T14 to a level comparable to that of T1. _pmTOR^S2448 was increased from T1 to X-T14 and did not decline over the training period. Single-fiber immunohistochemistry revealed a reduction in _prpS6^S235/236 in type I fibers from T1 to T13 and a re-increase at X-T14, which was more augmented in type II fibers at T13 (p < 0.05). The entity of myofibers revealed a high heterogeneity in the level of _prpS6^S235/236, possibly reflecting individual contraction-induced stress during RE. The type I and II myofiber diameter increased from T0 and T1 to T13 and X-T14 (p < 0.05) _prpS6^S235/236 and _pp70s6k^T421/S424 reflect RE-induced states of desensitization and re-sensitization in dependency on frequent loading by RE, but also by its cessation.     

The Development of Hindlimb Postural Asymmetry Induced by Focal Traumatic Brain Injury Is Not Related to Serotonin 2A/C Receptor Expression in the Spinal Cord

Brain injury and stroke are leading causes of adult disability. Motor deficits are common problems, and their underlying pathological mechanisms remain poorly understood. The serotoninergic system is implicated in both functional recovery from and the occurrence of spasticity after injuries to the central nervous system. This study, which was conducted on rats, investigated the development of limb postural changes and their relationship to the expression of serotonin (5-HT) 2A and 2C receptors in the spinal cord in the 4 weeks after focal traumatic brain injury (TBI) to the right hindlimb sensorimotor cortex. The limb motor deficits were assessed by measuring gait pattern changes during walking and hindlimb postural asymmetry at different time intervals (3–28 days) after surgery. The expressions of the 5-HT2A and 2C receptors in the lumbar spinal cord were investigated using immunohistochemistry. The results showed that all the rats with TBI, independently of the duration of the interval, displayed postural asymmetry with flexion on the contralateral (left) side (>2 mm), while the sham-operated rats showed no apparent postural asymmetry. The TBI rats also had longer stride lengths during walking in both their hindlimbs and their forelimbs compared with the sham rats. For both the TBI and the sham rats, the hind-paw placement angles were larger on the contralateral side in some of the groups. Compared to the sham-operated rats, the 5-HT2A and 2C receptor expression did not significantly change on either side of the lumbar spinal cords of the TBI rats in any of the groups. These results suggest that focal TBI can induce motor deficits lasting a relatively long time, and that these deficits are not related to the expression of the 5-HT2A and 2C receptors in the spinal cord.     

Introduction of zirconium oxide in a hardmask concept for highly selective patterning of scaled high aspect ratio trenches in silicon

The fabrication of high aspect ratio silicon trenches (critical dimension < 100 nm, aspect ratio > 10:1) by dry etch processing has proven to be a challenge mainly due to limited etch selectivity of conventional hardmask materials to Si. Moreover, for future technology nodes the hardmask thickness will be limited by the thickness of the photoresist. This work focuses on a concept to enable the usage of very thin resist layers (< 100 nm) for patterning of silicon trenches by the integration of an unconventional hardmask stack consisting of SiO₂ and ZrO₂. Deposition of such material films has been investigated, as well as e-beam lithography exposure and finally pattern transfer by dry etching. Using this hardmask stack and 100 nm thin resist, the fabrication of 35 nm wide trenches with an aspect ratio of ~ 20:1 is demonstrated revealing a very high selectivity (> 100:1) of the ZrO₂ layer to Si during the deep silicon etch. A silicon etch rate > 1.5 μm/min was achieved. The ZrO₂ layer itself provides the main selectivity improvements of the final hardmask stack.