VO2 Reserve vs. Heart Rate Reserve During Moderate Intensity Treadmill Exercise

International Journal of Exercise Science 7(4) : 311-317, 2014. ­VO2 and heart rate (HR) are widely used when determining appropriate training intensities for clinical, healthy, and athletic populations. It has been shown that if the % reserve (%R) is used, rather than % of max, HR and VO2 can be used interchangeably to accurately prescribe exercise intensities. Thus, heart rate reserve (HRR) can be prescribed if VO2 reserve (VO2R) is known. Therefore, the purpose of this study was to compare VO2 R and HRR during moderate intensity exercise (50%R). Physically active college students performed a maximal treadmill test to exhaustion. During which VO2 and HR were monitored to determine max values. Upon completion of the maximal test, calculations were made to determine the % grade expected to yield approximately 50% of the subjects VO2R. Subjects then returned to complete the submaximal test (50%R) at least two days later. The %VO2R and %HRR were calculated and compared to the predicted value as well as to each other. Statistical analysis revealed that VO2 at 50%R was significantly greater than the actual VO2 achieved, p \u3c .001. Conversely, the mean predicted HRat 50%R was significantly less than the actual HR achieved, p \u3c .001. In conclusion, this study indicated that VO2 could be more accurately predicted than HR during moderate intensity exercise. The weak correlation between VO2R and HRR indicates that caution should be used when relying on a HR to determine VO2

Direct Observation of Enzymes Replicating DNA Using a Single-molecule DNA Stretching Assay

We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system. Linearized λ DNA is modified to have a biotin on the end of one strand, and a digoxigenin moiety on the other end of the same strand. The biotinylated end is attached to a functionalized glass coverslip and the digoxigeninated end to a small bead. The assembly of these DNA-bead tethers on the surface of a flow cell allows a laminar flow to be applied to exert a drag force on the bead. As a result, the DNA is stretched close to and parallel to the surface of the coverslip at a force that is determined by the flow rate (Figure 1). The length of the DNA is measured by monitoring the position of the bead. Length differences between single- and double-stranded DNA are utilized to obtain real-time information on the activity of the replication proteins at the fork. Measuring the position of the bead allows precise determination of the rates and processivities of DNA unwinding and polymerization (Figure 2)

SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars

We present a review of precursor observing programs for the SIM PlanetQuest Key project devoted to detecting Jupiter mass planets around young stars. In order to ensure that the stars in the sample are free of various sources of astrometric noise that might impede the detection of planets, we have initiated programs to collect photometry, high contrast images, interferometric data and radial velocities for stars in both the Northern and Southern hemispheres. We have completed a high contrast imaging survey of target stars in Taurus and the Pleiades and found no definitive common proper motion companions within one arcsecond (140 AU) of the SIM targets. Our radial velocity surveys have shown that many of the target stars in Sco-Cen are fast rotators and a few stars in Taurus and the Pleiades may have sub-stellar companions. Interferometric data of a few stars in Taurus show no signs of stellar or sub-stellar companions with separations of <5 mas. The photometric survey suggests that approximately half of the stars initially selected for this program are variable to a degree (1 sigma>0.1 mag) that would degrade the astrometric accuracy achievable for that star. While the precursor programs are still a work in progress, we provide a comprehensive list of all targets ranked according to their viability as a result of the observations taken to date. By far, the observable that moves the most targets from the SIM-YSO program is photometric variability.Comment: Accepted for publication in Publications of the Astronomical Society of the Pacific, 25 pages, 9 figure

Effect of exercise intensity and volume on persistence of insulin sensitivity during training cessation

Effect of exercise intensity and volume on persistence of insulin sensitivity during training cessation. J Appl Physiol 106: 1079â 1085, 2009. First published February 5, 2009; doi:10.1152/japplphysiol.91262.2008. The purpose of this study was to determine whether exercise prescriptions differing in volume or intensity also differ in their ability to retain insulin sensitivity during an ensuing period of training cessation. Sedentary, overweight/obese subjects were assigned to one of three 8-mo exercise programs: 1) low volume/moderate intensity [equivalent of 12 miles/wk, 1,200 kcal/wk at 40-55% peak O2 consumption (VO2peak), 200 min exercise/wk], 2) low volume/vigorous intensity (12 miles/wk, 1,200 kcal/wk at 65-80% VO2peak, 125 min/wk), and 3) high volume/vigorous intensity (20 miles/wk, 2,000 kcal/wk at 65-80% VO2peak, 200 min/wk). Insulin sensitivity (intravenous glucose tolerance test, SI) was measured when subjects were sedentary and at 16-24 h and 15 days after the final training bout. SI increased with training compared with the sedentary condition (P less than or equal to 0.05) at 16-24 h with all of the exercise prescriptions. SI decreased to sedentary, pretraining values after 15 days of training cessation in the low-volume/vigorous-intensity group. In contrast, at 15 days SI was significantly elevated compared with sedentary (P less than or equal to 0.05) in the prescriptions utilizing 200 min/wk (low volume/moderate intensity, high volume/vigorous intensity). In the high-volume/vigorous-intensity group, indexes of muscle mitochondrial density followed a pattern paralleling insulin action by being elevated at 15 days compared with pretraining; this trend was not evident in the low-volume/moderateintensity group. These findings suggest that in overweight/obese subjects a relatively chronic persistence of enhanced insulin action may be obtained with endurance-oriented exercise training; this persistence, however, is dependent on the characteristics of the exercise training performed

Surgical site infection: poor compliance with guidelines and care bundles

Surgical site infections (SSIs) are probably the most preventable of the health care- associated infections. Despite the widespread international introduction of level I evidence-based guidelines for the prevention of SSIs, such as that of the National Institute for Clinical Excellence (NICE) in the UK and the surgical care improvement project (SCIP) of the USA, SSI rates have not measurably fallen. The care bundle approach is an accepted method of packaging best, evidence-based measures into routine care for all patients and, common to many guidelines for the prevention of SSI, includes methods for preoperative removal of hair (where appropriate), rational antibiotic prophylaxis, avoidance of perioperative hypothermia, management of perioperative blood glucose and effective skin preparation. Reasons for poor compliance with care bundles are not clear and have not matched the wide uptake and perceived benefit of the WHO ‘Safe Surgery Saves Lives’ checklist. Recommendations include the need for further research and continuous updating of guidelines; comprehensive surveillance, using validated definitions that facilitate benchmarking of anonymised surgeon-specific SSI rates; assurance that incorporation of checklists and care bundles has taken place; the development of effective communication strategies for all health care providers and those who commission services and comprehensive information for patients

Dynamics of DNA replication loops reveal temporal control of lagging-strand synthesis

In all organisms, the protein machinery responsible for the replication of DNA, the replisome, is faced with a directionality problem. The antiparallel nature of duplex DNA permits the leading-strand polymerase to advance in a continuous fashion, but forces the lagging-strand polymerase to synthesize in the opposite direction. By extending RNA primers, the lagging-strand polymerase restarts at short intervals and produces Okazaki fragments. At least in prokaryotic systems, this directionality problem is solved by the formation of a loop in the lagging strand of the replication fork to reorient the lagging-strand DNA polymerase so that it advances in parallel with the leading-strand polymerase. The replication loop grows and shrinks during each cycle of Okazaki fragment synthesis. Here we use single-molecule techniques to visualize, in real time, the formation and release of replication loops by individual replisomes of bacteriophage T7 supporting coordinated DNA replication. Analysis of the distributions of loop sizes and lag times between loops reveals that initiation of primer synthesis and the completion of an Okazaki fragment each serve as a trigger for loop release. The presence of two triggers may represent a fail-safe mechanism ensuring the timely reset of the replisome after the synthesis of every Okazaki fragment.

The Lantern Vol. 15, No. 2, Spring 1947

• Midsummer Afternoon\u27s Dream • Lost Love • The Rocket • Speak Now--- • Unique Experience • The Exile • Chronology • Procrustean Dike • A Faeble • The Paris Story • Inspiration • Gently Spoken • On Shavinghttps://digitalcommons.ursinus.edu/lantern/1041/thumbnail.jp

The Lantern Vol. 16, No. 1, Fall 1947

• A Little Light • Social Solidarity • The Struggle • 1949 Report • Blues • Angel\u27s Wings • Street Death • The Giant • Not Alone • B or Something • After Argument • Friendship • Built That Way • The Passing • Freshman • Asleep • John J. Heilemannhttps://digitalcommons.ursinus.edu/lantern/1043/thumbnail.jp

Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest

Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument that delivers parallaxes at about 4 microarcsec on targets as faint as V = 20, differential accuracy of 0.6 microarcsec on bright targets, and with flexible scheduling. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed all of the enabling technologies needed for the flight instrument in 2005. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. SIM will search for planets with masses as small as an Earth orbiting in the `habitable zone' around the nearest stars using differential astrometry, and could discover many dozen if Earth-like planets are common. It will be the most capable instrument for detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the galactic mass distribution and the formation and evolution of the Galactic halo. (abridged)Comment: 54 pages, 28 figures, uses emulateapj. Submitted to PAS