Differential activation of nerve fibers with magnetic stimulation in humans

Journal ArticleEarlier observations in our lab had indicated that large, time-varying magnetic fields could elicit action potentials that travel in only one direction in at least some of the myelinated axons in peripheral nerves. The objective of this study was to collect quantitative evidence for magnetically induced unidirectional action potentials in peripheral nerves of human subjects. A magnetic coil was maneuvered to a location on the upper arm where physical effects consistent with the creation of unidirectional action potentials were observed. Electromyographic (EMG) and somatosensory evoked potential (SEP) recordings were then made from a total of 20 subjects during stimulation with the magnetic coil

Comparison of Naphthalene Ambient Air Sampling & Analysis Methods at Former Manufactured Gas Plant (MGP) Remediation Sites

Naphthalene is a contaminant of concern at former Manufactured Gas Plant (MGP) and other property redevelopment sites across the country. A major component of coal tar waste and a possible human carcinogen (EPA Group C), naphthalene is a chemical that may adversely affect human health at remediation sites. Due to its boiling point and vapor pressure, naphthalene can exhibit both volatile and semi-volatile characteristics; therefore the question can arise as to how to properly measure naphthalene in ambient air. Two commonly applied methods of measuring vapor phase naphthalene include EPA Method TO-15, which utilizes whole air sampling in passivated stainless steel canisters; and EPA Method TO-13A, which utilizes high volume sorbent based sampling with polyurethane foam/XAD resin cartridges. Analytical differences between these two methods will be discussed, keeping reference to naphthalene’s unique chemical & physical properties. This case study will present weekly data spanning a twelve month period (December 2006 – December 2007) from co-located EPA Method TO-15 and TO-13A ambient air samples at the perimeter of two MGP cleanup remediation sites. Distinct trends are noted and discussed in this paper when comparing the concentration results from the two methods

Differential activation of nerve fibers with magnetic stimulation in humans

BACKGROUND: Earlier observations in our lab had indicated that large, time-varying magnetic fields could elicit action potentials that travel in only one direction in at least some of the myelinated axons in peripheral nerves. The objective of this study was to collect quantitative evidence for magnetically induced unidirectional action potentials in peripheral nerves of human subjects. A magnetic coil was maneuvered to a location on the upper arm where physical effects consistent with the creation of unidirectional action potentials were observed. Electromyographic (EMG) and somatosensory evoked potential (SEP) recordings were then made from a total of 20 subjects during stimulation with the magnetic coil. RESULTS: The relative amplitudes of the EMG and SEP signals changed oppositely when the current direction in the magnetic coil was reversed. This effect was consistent with current direction in the coil relative to the arm for all subjects. CONCLUSION: A differential evocation of motor and sensory fibers was demonstrated and indicates that it may be possible to induce unidirectional action potentials in myelinated peripheral nerve fibers with magnetic stimulation

Comparison of naphthalene methods at MGP sites

Naphthalene is a contaminant of concern at former Manufactured Gas Plant (MGP) and other property redevelopment sites across the country. A major component of coal tar waste and a possible human carcinogen (EPA Group C), naphthalene is a chemical that may adversely affect human health at remediation sites. Due to its boiling point and vapor pressure, naphthalene can exhibit both volatile and semi-volatile characteristics; therefore the question can arise as to how to properly measure naphthalene in ambient air. Two commonly applied methods of measuring vapor phase naphthalene include EPA Method TO-15, which utilizes whole air sampling in passivated stainless steel canisters; and EPA Method TO-13A, which utilizes high volume sorbent based sampling with polyurethane foam/XAD resin cartridges. Analytical differences between these two methods will be discussed, keeping reference to naphthalene’s unique chemical & physical properties. This case study will present weekly data spanning a twelve month period (December 2006 – December 2007) from co-located EPA Method TO-15 and TO-13A ambient air samples at the perimeter of two MGP cleanup remediation sites. Distinct trends are noted and discussed in this paper when comparing the concentration results from the two methods

Comparison Of Naphthalene Ambient Air Sampling & Analysis Methods

Naphthalene is a contaminant of concern at former Manufactured Gas Plant (MGP) and other property redevelopment sites across the country. A major component of coal tar waste and a possible human carcinogen (EPA Group C), naphthalene is a chemical that may adversely affect human health at remediation sites. Due to its boiling point and vapor pressure, naphthalene can exhibit both volatile and semi-volatile characteristics; therefore the question can arise as to how to properly measure naphthalene in ambient air. Two commonly applied methods of measuring vapor phase naphthalene include EPA Method TO-15, which utilizes whole air sampling in passivated stainless steel canisters; and EPA Method TO-13A, which utilizes high volume sorbent based sampling with polyurethane foam/XAD resin cartridges. Analytical differences between these two methods are discussed, keeping reference to naphthalene’s unique chemical & physical properties. This case study presents weekly data spanning a twelve month period (December 2006 – December 2007) from co-located EPA Method TO-15 and TO-13A ambient air samples at the perimeter of two MGP cleanup remediation sites. Distinct trends are noted and discussed in this paper when comparing the concentration results from the two methods