As part of an NIH-funded study of malaria pathogenesis, a magnetic resonance (MR) imaging research facility was established in Blantyre, Malaŵi to enhance the clinical characterization of pediatric patients with cerebral malaria through application of neurological MR methods. The research program requires daily transmission of MR studies to Michigan State University (MSU) for clinical research interpretation and quantitative post-processing. An intercontinental satellite-based network was implemented for transmission of MR image data in Digital Imaging and Communications in Medicine (DICOM) format, research data collection, project communications, and remote systems administration. Satellite Internet service costs limited the bandwidth to symmetrical 384 kbit/s. DICOM routers deployed at both the Malaŵi MRI facility and MSU manage the end-to-end encrypted compressed data transmission. Network performance between DICOM routers was measured while transmitting both mixed clinical MR studies and synthetic studies. Effective network latency averaged 715 ms. Within a mix of clinical MR studies, the average transmission time for a 256 × 256 image was ~2.25 and ~6.25 s for a 512 × 512 image. Using synthetic studies of 1,000 duplicate images, the interquartile range for 256 × 256 images was [2.30, 2.36] s and [5.94, 6.05] s for 512 × 512 images. Transmission of clinical MRI studies between the DICOM routers averaged 9.35 images per minute, representing an effective channel utilization of ~137% of the 384-kbit/s satellite service as computed using uncompressed image file sizes (including the effects of image compression, protocol overhead, channel latency, etc.). Power unreliability was the primary cause of interrupted operations in the first year, including an outage exceeding 10 days.

PURPOSE Calibration reference phantoms exhibiting long-term chemical stability and temperature-insensitive R2*/T2* relaxation are needed in longitudinal research studies employing quantitative R2* methods to improve the sensitivity and reproducibility of R2* measurements, to detect and correct bias, and to decrease the variance of pooled study data. The relevant literature is sparse. This project aims to design and evaluate a R2* phantom that is stable over time and temperature, and mimics organ tissue T1 and T2.

Quantifying mechanical output is fundamental to understanding metabolism that fuels muscle contraction and more recent attempts to understand signal transduction and gene regulation. The latter requires long-term application of exercise protocols that result in large amounts of data on muscle performance. The purpose of this study was to develop software for automated quantification of skeletal muscle contractions. An in situ mouse sciatic nerve stimulation model was used to produce contractions over a broad range of frequencies and recorded as both digital and analog signals using a PC analog to digital converter board and chart recorder, respectively. Spectral analysis of the noise components formed the basis for designing a smoothing Chebyshev filter. Algorithms implemented in custom software identified twitches and estimated baseline levels from the smoothed signal. The time to peak force, peak force, tension-time integral, and half-relaxation time were determined for each twitch after baseline correction. The automated results were compared to those obtained from manual measurements of the analog signal. Bland–Altman analysis of the parameters computed from digital signals compared with the corresponding measurements by manual planometry demonstrates the agreement of the digital processing algorithm with planometry over a wide range of twitch characteristics. This program may also be used to study the mechanics of other preparations from isolated muscles, human proximal limb performance, and other digital physiologic signals. Adaptation of the filter function is required to apply the analysis to another experimental apparatus with differing noise characteristics. A full version of the program and instructions for its use are available for download at www.rad.msu.edu.

Introduction Myocardial perfusion reserve quantifies the capacity of the circulatory response to a maximal increase in metabolic demand. MPR indicates the net circulatory consequence from coronary lesions and other vascular states, regardless of their morphological appearance, including the compensation by collateral flow. Myocardial collaterals readily develop in response to ischemia induced by upstream stenosis or occlusion. In canine model, Ameroid constrictors will induce new coronary collaterals providing perfusion of ~35% of maximal normal blood flow in ~95% of dogs. Recent improvements in perfusion acquisition methods now provide increased temporal and spatial resolution, SNR, and first-pass contrast enhancement ratio. Semiquantitative MPR can be achieved with MR methods using current USFDA-approved contrast agents.

The establishment of the medfly in California would have significant impacts, particulary on the citrus industry. This study investigates the economic impacts that might arise if Asian countries imposed an embargo on California produce. Increased costs of controlling an established medfly, whether or not an embargo were imposed, would range from $493 million to $875 million. The imposition of an embargo would result in additional revenue losses of $564 million. The state economy could lose $1.2 billion in gross state product and more than 14,000 jobs.