Two major accretion epochs in M31 from two distinct populations of globular clusters.

Large galaxies grow through the accumulation of dwarf galaxies1,2. In principle it is possible to trace this growth history via the properties of a galaxy's stellar halo3-5. Previous investigations of the galaxy Messier 31 (M31, Andromeda) have shown that outside a galactocentric radius of 25 kiloparsecs the population of halo globular clusters is rotating in alignment with the stellar disk6,7, as are more centrally located clusters8,9. The M31 halo also contains coherent stellar substructures, along with a smoothly distributed stellar component10-12. Many of the globular clusters outside a radius of 25 kiloparsecs are associated with the most prominent substructures, but some are part of the smooth halo13. Here we report an analysis of the kinematics of these globular clusters. We find two distinct populations rotating perpendicular to each other. The rotation axis for the population associated with the smooth halo is aligned with the rotation axis for the plane of dwarf galaxies14 that encircles M31. We interpret these separate cluster populations as arising from two major accretion epochs, probably separated by billions of years. Stellar substructures from the first epoch are gone, but those from the more recent second epoch still remain.

Using a Lean Six Sigma Approach to Yield Sustained Pressure Ulcer Prevention for Complex Critical Care Patients.

BACKGROUND: Under value-based purchasing, Medicare withholds reimbursements for hospital-acquired pressure ulcer occurrence and rewards hospitals that meet performance standards. With little evidence of a validated prevention process, nurse managers are challenged to find evidence-based interventions. OBJECTIVE: The aim of this study was to reduce the unit-acquired pressure ulcer (UAPU) rate on targeted intensive care and step-down units by 15% using Lean Six Sigma (LSS) methodology. METHODS: An interdisciplinary team designed a pilot program using LSS methodology to test 4 interventions: standardized documentation, equipment monitoring, patient out-of-bed-to-chair monitoring, and a rounding checklist. RESULTS: During the pilot, the UAPU rate decreased from 4.4% to 2.8%, exceeding the goal of a 15% reduction. The rate remained below the goal through the program control phase at 2.9%, demonstrating a statistically significant reduction after intervention implementation. CONCLUSIONS: The program significantly reduced UAPU rates in high-risk populations. LSS methodologies are a sustainable approach to reducing hospital-acquired conditions that should be broadly tested and implemented.

Improving Nursing Knowledge of Alcohol Withdrawal: Second Generation Education Strategies.

Christiana Care Health System implemented a Care Management Guideline for Alcohol Withdrawal Symptom Management, which provided direction for inpatient screening for alcohol withdrawal risk, assessment, and treatment. Nurses educated on its use expressed confusion with the use of the assessment tools, pharmacokinetics, and pathophysiology of alcohol withdrawal and delirium tremens. Reeducation was provided by nursing professional development specialists. Pre- and postsurveys revealed that nurses were more confident in caring for patients with alcohol withdrawal.

Exploration of Social, Environmental, and Familial Influences on the Sexual Health Practices of Urban African American Adolescents.

Despite efforts to examine social influences and provide interventions that lead to safer sexual practices for African American (AA) adolescent girls, statistics have demonstrated this population continues to have the highest rates of teen pregnancy and sexually transmitted infections (STIs) including HIV when compared with adolescent girls of other races. Guided by the principles of Black Feminist Thought and Photovoice and focus group methodology, this descriptive study aimed to discover the social realities influencing a group of eight AA adolescent girls aged 15 to 19 years. Data from individual interviews and a focus group session were collected from November 11, 2012, to February 1, 2013. Analysis of selected photographs, interviews, and focus group conversations through a feminist lens suggests AA adolescents of low socioeconomic status continue to foster racial and mental inferiority stereotypes by using their sexuality as a bargaining tool for acceptance, value, and even love.

A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy.

Dwarf satellite galaxies are thought to be the remnants of the population of primordial structures that coalesced to form giant galaxies like the Milky Way. It has previously been suspected that dwarf galaxies may not be isotropically distributed around our Galaxy, because several are correlated with streams of H I emission, and may form coplanar groups. These suspicions are supported by recent analyses. It has been claimed that the apparently planar distribution of satellites is not predicted within standard cosmology, and cannot simply represent a memory of past coherent accretion. However, other studies dispute this conclusion. Here we report the existence of a planar subgroup of satellites in the Andromeda galaxy (M 31), comprising about half of the population. The structure is at least 400 kiloparsecs in diameter, but also extremely thin, with a perpendicular scatter of less than 14.1 kiloparsecs. Radial velocity measurements reveal that the satellites in this structure have the same sense of rotation about their host. This shows conclusively that substantial numbers of dwarf satellite galaxies share the same dynamical orbital properties and direction of angular momentum. Intriguingly, the plane we identify is approximately aligned with the pole of the Milky Way's disk and with the vector between the Milky Way and Andromeda.

Using an automated cell counter to simplify gene expression studies: siRNA knockdown of IL-4 dependent gene expression in Namalwa cells.

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression. siRNA studies are being conducted not only to study the effects of downregulating single genes, but also to interrogate signaling pathways and other complex interaction networks. These pathway analyses require both the use of relevant cellular models and methods that cause less perturbation to the cellular physiology. Electroporation is increasingly being used as an effective way to introduce siRNA and other nucleic acids into difficult to transfect cell lines and primary cells without altering the signaling pathway under investigation. There are multiple critical steps to a successful siRNA experiment, and there are ways to simplify the work while improving the data quality at several experimental stages. To help you get started with your siRNA mediated gene knockdown project, we will demonstrate how to perform a pathway study complete from collecting and counting the cells prior to electroporation through post transfection real-time PCR gene expression analysis. The following study investigates the role of the transcriptional activator STAT6 in IL-4 dependant gene expression of CCL17 in a Burkitt lymphoma cell line (Namalwa). The techniques demonstrated are useful for a wide range of siRNA-based experiments on both adherent and suspension cells. We will also show how to streamline cell counting with the TC10 automated cell counter, how to electroporate multiple samples simultaneously using the MXcell electroporation system, and how to simultaneously assess RNA quality and quantity with the Experion automated electrophoresis system.

Using the gene pulser MXcell electroporation system to transfect primary cells with high efficiency.

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

The remnants of galaxy formation from a panoramic survey of the region around M31.

In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound stars surrounding the galaxy, at distances that reach 10-100 times the radius of the central disk. The number, luminosity and morphology of the relics of this process provide significant clues to galaxy formation history, but obtaining a comprehensive survey of these components is difficult because of their intrinsic faintness and vast extent. Here we report a panoramic survey of the Andromeda galaxy (M31). We detect stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31. An improved census of their surviving counterparts implies that three-quarters of M31's satellites brighter than M(v) = -6 await discovery. The brightest companion, Triangulum (M33), is surrounded by a stellar structure that provides persuasive evidence for a recent encounter with M31. This panorama of galaxy structure directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.

Creation of a stepdown nurse internship program.

Within Christiana Care Health System, an opportunity evolved to develop a nurse recruitment strategy for our stepdown units. Being a large teaching system, there was specific need for nursing education at this entry level. Through collaboration of nursing colleagues, the Stepdown Nurse Internship Program was created. The program encompassed clinical orientation and didactic classes. Of notable significance at the completion of the program were the Basic Knowledge Assessment Test score improvement and the nurse retention rate.

Characterisation of complex formation between members of the Mycobacterium tuberculosis complex CFP-10/ESAT-6 protein family: towards an understanding of the rules governing complex formation and thereby functional flexibility.

We have previously shown that the secreted M. tuberculosis complex proteins CFP-10 and ESAT-6 form a tight, 1:1 complex, which may represent their functional form. In the work reported here a combination of yeast two-hybrid and biochemical analysis has been used to characterise complex formation between two other pairs of CFP-10/ESAT-6 family proteins (Rv0287/Rv0288 and Rv3019c/Rv3020c) and to determine whether complexes can be formed between non-genome paired members of the family. The results clearly demonstrate that Rv0287/Rv0288 and Rv3019c/3020c form tight complexes, as initially observed for CFP-10/ESAT-6. The closely related Rv0287/Rv0288 and Rv3019c/Rv3020c proteins are also able to form non-genome paired complexes (Rv0287/Rv3019c and Rv0288/Rv3020c), but are not capable of binding to the more distantly related CFP-10/ESAT-6 proteins.

Effect of nucleoside reverse transcriptase inhibitors on mitochondrial DNA synthesis in rats and humans.

Nucleoside reverse transcriptase inhibitors (NRTIs) have been hypothesized to inhibit mitochondrial DNA polymerase gamma, resulting in decreased mtDNA synthesis and mitochondrial insufficiency in HIV-1-infected patients. mtDNA synthesis was measured directly using a stable isotope mass spectrometric method following NRTI treatment in rodents. 3'-Azido-3'-deoxythymidine (AZT) was added to water (1 mg/mL) and administered ad libitum to female Sprague-Dawley rats for 1-8 weeks (n = 4 or 5 animals/timepoint). Neither body weight nor food intake was affected by AZT intake. Untreated controls and AZT-treated rats were given 4% H2O as drinking water for 2 weeks. AZT (approximately 100 mg/kg/d) produced a significant (P < 0.05) decrease in cardiac and hindlimb muscle mtDNA fractional synthesis compared with control groups (from 13.8 +/- 4.2% to 7.0 +/- 4.8% and from 7.6 +/- 1.8% to 4.5 +/- 0.4%, respectively) after 4 weeks. Cytochrome c oxidase content in hindlimb muscle was also decreased by 50% compared with controls after 4 weeks of AZT treatment (P < 0.07) and a calculated index of absolute mitochondrial biogenesis rate was significantly reduced by week 2 of AZT (P < 0.05) in hindlimb muscle. In preliminary studies, platelet mtDNA enrichments were compared to monocyte nDNA enrichments (used as a marker of a fully turned over tissue) in healthy human subjects. Fractional synthesis of mtDNA in platelets reached 98 +/- 3% after 5 weeks of H2O labeling. It is concluded that NRTIs decrease mtDNA synthesis and oxidative enzyme content and thus mitochondrial biogenesis in rodents and that the effects of NRTIs on mitochondrial biogenesis in tissues of HIV-1- infected humans can in principle be measured using this approach.

Measurement of mitochondrial DNA synthesis in vivo using a stable isotope-mass spectrometric technique.

We describe here a new stable isotope-mass spectrometric technique for measuring mitochondrial DNA (mtDNA) synthesis. Growing (2-4 mo old) and weight-stable (8-10 mo old) Sprague-Dawley rats were primed with (2)H(2)O (deuterated water) to 2.0-2.5% body water enrichment, via intraperitoneal injection, and then given 4% (2)H(2)O in drinking water for 3-11 wk. Mitochondria were isolated from cardiac and hindlimb muscle, and mtDNA was isolated and enzymatically hydrolyzed to deoxyribonucleosides. PCR confirmed the absence of nuclear DNA contamination. The isotopic enrichment of the deoxyribose moiety of deoxyadenosine was determined by GC-MS analysis, and percent new mtDNA was calculated by comparison to genomic DNA enrichments in a tissue with nearly complete turnover (bone marrow). Initial label incorporation into deoxyadenosine of mtDNA was linear, and turnover of mtDNA was observed in nongrowing adult female rats (1.1-1.3% new mtDNA per day in cardiac and skeletal muscle). Die-away curves of mtDNA after discontinuing (2)H(2)O administration gave a similar turnover rate constant. Human subjects were also given (2)H(2)O for up to 6 wk, and mitochondria from platelets were isolated. Incubation with DNase removed any contaminating genomic DNA; platelet mtDNA exhibited linear incorporation from (2)H(2)O and reached plateau values identical to those in genomic DNA from fully turned over cells (circulating monocytes). In conclusion, replication of mtDNA can be directly measured in vivo in rodents and humans without the use of radioactivity. Use of this technique may allow improved understanding of the regulation of mitochondrial biogenesis in health and disease.