Motorcycle and bicycle safety helmets must adhere to specific technical requirements in order to provide protection. Various helmet configurations illustrate success with the application of these principles as well as failure by the neglect of these technical principles. The most critical feature of truly protective headgear is the use of a significant amount of energy absorbing material for the liner of the safety helmet. The most successful safety helmets have been built to standards that incorporate these technical requirements as basic performance in the areas of retention systems and impact attenuation. The qualification of the safety helmet to the basic technical requirements insures protection to the covered integument as well as prevention of a class of “contact” injuries including skull fractures and intracranial injuries. In addition, the qualified safety helmet is shown to prevent or reduce most of a class of “inertial” injuries, but with certain limitations of specific rotational injuries which can not be excluded by any protective device.

Endothelin-1 (ET-1), tissue plasminogen activator (tPA), and extracellular signal-regulated kinases-mitogen activated protein kinase (ERK-MAPK) are mediators of impaired cerebral hemodynamics after fluid percussion brain injury (FPI) in piglets. Microparticles (MPs) are released into the circulation from a variety of cells during stress, are pro-thrombotic and pro-inflammatory, and may be lysed with polyethylene glycol telomere B (PEG-TB). We hypothesized that MPs released after traumatic brain injury impair hypotensive cerebrovasodilation and that PEG-TB protects the vascular response via MP lysis, and we investigated the relationship between MPs, tPA, ET-1, and ERK-MAPK in that process. FPI was induced in piglets equipped with a closed cranial window. Animals received PEG-TB or saline (vehicle) 30-minutes post-injury. Serum and cerebrospinal fluid (CSF) were sampled and pial arteries were measured pre- and post-injury. MPs were quantified by flow cytometry. CSF samples were analyzed with enzyme-linked immunosorbent assay. MP levels, vasodilatory responses, and CSF signaling assays were similar in all animals prior to injury and treatment. After injury, MP levels were elevated in the serum of vehicle but not in PEG-TB-treated animals. Pial artery dilation in response to hypotension was impaired after injury but protected in PEG-TB-treated animals. After injury, CSF levels of tPA, ET-1, and ERK-MAPK were all elevated, but not in PEG-TB-treated animals. PEG-TB-treated animals also showed reduction in neuronal injury in CA1 and CA3 hippocampus, compared with control animals. These results show that serum MP levels are elevated after FPI and lead to impaired hypotensive cerebrovasodilation via over-expression of tPA, ET-1, and ERK-MAPK. Treatment with PEG-TB after injury reduces MP levels and protects hypotensive cerebrovasodilation and limits hippocampal neuronal cell injury.

Over-wintering crops are known to reduce nutrients in soil leachate in spring, but little economic incentive is available to grow these crops in the Upper Midwest. New oilseed-bearing cash cover crops, such as winter camelina and pennycress, may provide the needed incentives. However, the abilities of these crops to sequester labile soil nutrients are unknown. We used lysimeters buried at 30, 60, and 100 cm to examine nitrate and soil reactive phosphorus (SRP) in six soybean cropping system treatments: clean till, no-till, and autumn-seeded radish, winter rye, pennycress, and winter camelina. Radish winter-killed naturally, winter rye was killed with a glyphosate, and pennycress and winter camelina were allowed to mature naturally after relay sowing of soybean. Leachate chemistry was studied for the autumn, spring, and summer periods over two growing season. In autumn, leachates under radish and winter rye tended to have the lowest nitrate levels. In spring, differences among nitrate levels across treatments were greater than at any other time period, with values much lower under pennycress and winter camelina treatments than other treatments. In summer, nitrate levels were more uniform, with the lowest values occurring where soybean grew best. In general, cash cover crops like pennycress and winter camelina provide both environmental and economic resources to growers in that they represent cash-generating grain crops that sequester labile soil nutrients, especially in spring, and protect and promote soil health from autumn through early summer.

No abstract

No abstract