Andrew J. Berger

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We propose a method to isolate absorption trends confined to the lower layer of a two-layer turbid medium, as is desired in near-infrared spectroscopy (NIRS) of cerebral hemodynamics. Several two-layer Monte Carlo simulations of NIRS time series were generated using a physiologically relevant range of optical properties and varying the absorption(More)
In near-infrared spectroscopy (NIRS) of human cerebral hemodynamics, detection of stimulus-related responses is confounded by the presence of unrelated trends in both the brain and the overlying scalp. A proposed strategy for reducing hemodynamic noise has been to record "scalp only" trends simultaneously via a second shorter-separation detector (~5 mm(More)
Functional near infrared spectroscopy (fNIRS) is a portable monitor of cerebral hemodynamics with wide clinical potential. However, in fNIRS, the vascular signal from the brain is often obscured by vascular signals present in the scalp and skull. In this paper, we evaluate two methods for improving in vivo data from adult human subjects through the use of(More)
A multidetector, continuous wave, near-infrared spectroscopy (NIRS) system is developed to examine whether the hemodynamics of the scalp and brain in adults contain significant layer-like hemodynamic trends. NIRS measurements are made using contrasting geometries, one with four detectors equidistant from a source 33 mm away, and one with detectors collinear(More)
Spectroscopic methods of urinalysis offer several advantages over chemical methods, including less sample contact and higher information content. In particular, urine creatinine has been the subject of several spectroscopic studies. We report the first use of Raman spectroscopy to measure creatinine concentrations in unaltered urine samples from a(More)
We report measurements of chemical concentrations in clinical blood serum and urine samples using liquid-core optical fiber (LCOF) Raman spectroscopy to increase the collected signal strength. Both Raman and absorption spectra were acquired in the near-infrared region using the LCOF geometry. Spectra of 71 blood serum and 61 urine samples were regressed via(More)
BACKGROUND Exposure to lead (Pb) from environmental and industrial sources remains an overlooked serious public health risk. Elucidating the effect of Pb on bone cell function is therefore critical for understanding its risk associated with diseases of low bone mass. OBJECTIVES We tested the hypothesis that Pb negatively affects bone mass. We also(More)
Clinical prediction of bone fracture risk primarily relies on measures of bone mineral density (BMD). BMD is strongly correlated with bone strength, but strength is independent of fracture toughness, which refers to the bone's resistance to crack initiation and propagation. In that sense, fracture toughness is more relevant to assessing fragility-related(More)
OBJECTIVE Glucocorticoid (GC) therapy is associated with increased risk of fracture in patients with rheumatoid arthritis (RA). To elucidate the cause of this increased risk, we examined the effects of chronic erosive inflammatory arthritis and GC treatment on bone quality, structure, and biomechanical properties in a murine model. METHODS Mice with(More)