Enhanced adhesion of PMMA to copper with black oxide for electrodeposition of high aspect ratio nickel-iron microstructures

 Copper is widely used as a plating base for soft magnetic alloy electrodeposition in sensors and actuators. PMMA, the X-ray resist used in the LIGA process, typically has poor adhesion with copper. The use of black oxide of copper to enhance PMMA-copper adhesion was investigated. In this work, peel strength as a function of treatment time and the method of bonding was evaluated using an ASTM standard T-peel test. Peel strength increased with increasing treatment time. The feasibility of producing microstructures with predictable 3-D geometry for use in resonating sensors was investigated using the process developed. Nickel-iron structures of 100-1000 micrometers wide and 500 micrometers tall were successfully electrodeposited. Growth of other representative microstructures is being investigated. Received: 25 August 1997/Accepted: 3 September 1977     

Trial by fire [rescue robots]

On September 11, 2001, the Center for Robot-Assisted Search and Rescue (CRASAR) responded within six hours to the World Trade Center (WTC) disaster; this is the first known use of robots for urban search and rescue (USAR). The University of South Florida (USF) was one of the four robot teams, and the only academic institution represented. The USF team participated onsite in the search efforts from 12-21 September 2001, collecting and archiving data on the use of all robots, in addition to actively fielding robots. This article provides an overview of the use of robots for USAR, concentrating on what robots were actually used and why. It describes the roles that the robots played in the response and the impact of the physical environment on the platforms. The quantitative and qualitative performance of the robots are summarized in terms of their components (mobility, sensors, control, communications, and power) and within the larger human-robot system. Lessons learned are offered and a synopsis of the current state of rescue robotics and activities at the CRASAR concludes the article.     

Sediment-associated metals levels along the sewer-natural treatment wetland continuum,Phnom Penh,Cambodia

Sediment deposited within open sewers of Phnom Penh and the natural wetland that treats the waste was sampled and analyzed by X-ray fluorescence (XRF). Mean levels of Pb, Zn (P < 0.05), and Cu (P = 0.08) were greater in the sewer samples than the wetland, while As was not different (P>0.2), and Mn was greater (P < 0.06) in the wetland. Pb, Cu, and Zn levels generally were lower at the wetland outlet and in quiescent areas, suggesting deposition occurs along the sewer/wetland continuum. Background (natural) levels of Mn and As are higher in soils/sediments of this region and levels in the wetland likely reflect these background levels than enrichment from anthropogenic activity. Although 60% of all metals levels in the wetland samples exceeded USEPA threshold effect concentrations, results of recent studies that analyzed fish and vegetables from the wetland showed a small health risk associated with consumption. The XRF was a good tool for environmental analysis in a developing country.     

Improvements to the structural condition index (SCI) for pavement structural evaluation at network level

Structural evaluation provides valuable information about the expected behaviour and response of pavements and can be used at the network level of pavement management to prioritise projects. The falling weight deflectometer (FWD) can be used to identify the beginning and end of management sections and group pavement sections with similar structural capacities. The structural condition index (SCI) was developed as a screening tool for the pavement network-level evaluation, and the FWD data are used to determine the SCI. For the successful implementation of the SCI concept at the network level, one of the critical issues is the accuracy of the index. This article evaluates the accuracy of the SCI and also discusses a concept and procedure how to improve the SCI and its algorithm for low-volume flexible pavements. A case study (Texas) illustrates that the original SCI algorithm underestimates the existing structural condition, resulting in overestimated treatments in the pavement maintenance and rehabilitation.     

Three-dimensional imaging of human stem cells using soft X-ray tomography

Three-dimensional imaging of human stem cells using transmission soft X-ray tomography (SXT) is presented for the first time. Major organelle types—nuclei, nucleoli, mitochondria, lysosomes and vesicles—were discriminated at approximately 50 nm spatial resolution without the use of contrast agents, on the basis of measured linear X-ray absorption coefficients and comparison of the size and shape of structures to transmission electron microscopy (TEM) images. In addition, SXT was used to visualize the distribution of a cell surface protein using gold-labelled antibody staining. We present the strengths of SXT, which include excellent spatial resolution (intermediate between that of TEM and light microscopy), the lack of the requirement for fixative or contrast agent that might perturb cellular morphology or produce imaging artefacts, and the ability to produce three-dimensional images of cells without microtome sectioning. Possible applications to studying the differentiation of human stem cells are discussed.     

An exposure based study of crash and injury rates in a cohort of transport and recreational cyclists in New South Wales,Australia

This paper examines self-reported prospectively collected data from 2038 adult transport and recreational cyclists from New South Wales (Australia) to determine exposure-based incident crash and injury rates. During 25,971 days of cycling, 198 crashes were reported, comprising approximately equal numbers of falls and collisions. The overall crash rate was 0.290 (95% CI, 0.264–0.319) per 1000 km or 6.06 (95% CI, 5.52–6.65) per 1000 h of travel. The rate of crashes causing any injury (self-treated, or medically attended without overnight hospital stay) was 0.148 (95% CI, 0.133–0.164) per 1000 km or 3.09 (95% CI, 2.79-3.43) per 1000 h of travel. The rate of crashes causing a medically attended injury (without overnight hospital stay) was 0.023 (95% CI, 0.020–0.027) per 1000 km or 0.49 (95% CI, 0.43-0.56) per 1000 h of travel. No injuries requiring an overnight stay in hospital were reported on days meeting the inclusion criteria. After adjustment for exposure in hours, or for the risks associated with different infrastructure utilisation, the rates of crashes and medically attended injuries were found to be greater for females than males, less experienced than more experienced cyclists, and for those who rode mainly for transport rather than mainly for recreation. Comparison of estimated crash and injury rates on different infrastructure types were limited by the small number of events, however findings suggest that the separation of cyclists from motorised traffic is by itself not sufficient to ensure safe cycling.     

Hematopoietic Progenitors and the Bone Marrow Niche Shape the Inflammatory Response and Contribute to Chronic Disease

It is now well understood that the bone marrow (BM) compartment can sense systemic inflammatory signals and adapt through increased proliferation and lineage skewing. These coordinated and dynamic alterations in responding hematopoietic stem and progenitor cells (HSPCs), as well as in cells of the bone marrow niche, are increasingly viewed as key contributors to the inflammatory response. Growth factors, cytokines, metabolites, microbial products, and other signals can cause dysregulation across the entire hematopoietic hierarchy, leading to lineage-skewing and even long-term functional adaptations in bone marrow progenitor cells. These alterations may play a central role in the chronicity of disease as well as the links between many common chronic disorders. The possible existence of a form of “memory” in bone marrow progenitor cells is thought to contribute to innate immune responses via the generation of trained immunity (also called innate immune memory). These findings highlight how hematopoietic progenitors dynamically adapt to meet the demand for innate immune cells and how this adaptive response may be beneficial or detrimental depending on the context. In this review, we will discuss the role of bone marrow progenitor cells and their microenvironment in shaping the scope and scale of the immune response in health and disease.