1,209 research outputs found
Resonance Raman Spectroscopy of extreme nanowires and other 1D systems
This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample
Induced chromosome deletions cause hypersociability and other features of Williams-Beuren syndrome in mice
The neurodevelopmental disorder Williams-Beuren syndrome is caused by spontaneous similar to 1.5 Mb deletions comprising 25 genes on human chromosome 7q11.23. To functionally dissect the deletion and identify dosage-sensitive genes, we created two half-deletions of the conserved syntenic region on mouse chromosome 5G2. Proximal deletion (PD) mice lack Gtf2i to Limk1, distal deletion (DD) mice lack Limk1 to Fkbp6, and the double heterozygotes (D/P) model the complete human deletion. Gene transcript levels in brain are generally consistent with gene dosage. Increased sociability and acoustic startle response are associated with PD, and cognitive defects with DD. Both PD and D/P males are growth-retarded, while skulls are shortened and brains are smaller in DD and D/P. Lateral ventricle (LV) volumes are reduced, and neuronal cell density in the somatosensory cortex is increased, in PD and D/P. Motor skills are most impaired in D/P. Together, these partial deletion mice replicate crucial aspects of the human disorder and serve to identify genes and gene networks contributing to the neural substrates of complex behaviours and behavioural disorders
Implementing Service Learning in Pre-service Teacher Coursework
Service learning remains a topic of interest in higher education. It has become more prevalent in teacher preparation programs with the intent of providing the opportunity for pre-service teachers to become engaged with individuals who have different life experiences than their own. Lessons can be learned through a review of the literature and the examination of existing models of service learning, including an honest discussion of the advantages and potential barriers for all stakeholders
WISE Discovery of Low Metallicity Blue Compact Dwarf Galaxies
We report two new low metallicity blue compact dwarf galaxies (BCDs), WISEP
J080103.93+264053.9 (hereafter W0801+26) and WISEP J170233.53+180306.4
(hereafter W1702+18), discovered using the Wide-field Infrared Survey Explorer
(WISE). We identified these two BCDs from their extremely red colors at
mid-infrared wavelengths, and obtained follow-up optical spectroscopy using the
Low Resolution Imaging Spectrometer on Keck I. The mid-infrared properties of
these two sources are similar to the well studied, extremely low metallicity
galaxy SBS 0335-052E. We determine metallicities of 12 + log(O/H) = 7.75 and
7.63 for W0801+26 and W1702+18, respectively, placing them amongst a very small
group of very metal deficient galaxies (Z 300 Angstrom
Hbeta equivalent widths, similar to SBS 0335-052E, imply the existence of young
(< 5 Myr) star forming regions. We measure star formation rates of 2.6 and 10.9
Msun/yr for W0801+26 and W1702+18, respectively. These BCDs, showing recent
star formation activity in extremely low metallicity environments, provide new
laboratories for studying star formation in extreme conditions and are
low-redshift analogs of the first generation of galaxies to form in the
universe. Using the all-sky WISE survey, we discuss a new method to identify
similar star forming, low metallicity BCDs.Comment: Accepted for publication in ApJ
The Effect of the South Pacific Convergence Zone on the Termination of El Niño Events and the Meridional Asymmetry of ENSO*
Coagulation factor IX gene transfer to non-human primates using engineered AAV3 capsid and hepatic optimized expression cassette
Hepatic gene transfer with adeno-associated viral (AAV) vectors shows much promise for the treatment of the X-linked bleeding disorder hemophilia B in multiple clinical trials. In an effort to further innovate this approach and to introduce alternative vector designs with potentially superior features into clinical development, we recently built a vector platform based on AAV serotype 3 because of its superior tropism for human hepatocytes. A vector genome with serotype-matched inverted terminal repeats expressing hyperactive human coagulation factor IX (FIX)-Padua was designed for clinical use that is optimized for translation using hepatocyte-specific codon-usage bias and is depleted of immune stimulatory CpG motifs. Here, this vector genome was packaged into AAV3 (T492V + S663V) capsid for hepatic gene transfer in non-human primates. FIX activity within or near the normal range was obtained at a low vector dose of 5 x 10(11) vector genomes/kg. Pre-existing neutralizing antibodies, however, completely or partially blocked hepatic gene transfer at that dose. No CD8(+) T cell response against capsid was observed. Antibodies against the human FIX transgene product formed at a 10-fold higher vector dose, albeit hepatic gene transfer was remarkably consistent, and sustained FIX activity in the normal range was nonetheless achieved in two of three animals for the 3-month duration of the study. These results support the use of this vector at low vector doses for gene therapy of hemophilia B in humans
Internal dose assessment of 210Po using biokinetic modeling and urinary excretion measurement
The mysterious death of Mr. Alexander Litvinenko who was most possibly poisoned by Polonium-210 (210Po) in November 2006 in London attracted the attention of the public to the kinetics, dosimetry and the risk of this high radiotoxic isotope in the human body. In the present paper, the urinary excretion of seven persons who were possibly exposed to traces of 210Po was monitored. The values measured in the GSF Radioanalytical Laboratory are in the range of natural background concentration. To assess the effective dose received by those persons, the time-dependence of the organ equivalent dose and the effective dose after acute ingestion and inhalation of 210Po were calculated using the biokinetic model for polonium (Po) recommended by the International Commission on Radiological Protection (ICRP) and the one recently published by Leggett and Eckerman (L&E). The daily urinary excretion to effective dose conversion factors for ingestion and inhalation were evaluated based on the ICRP and L&E models for members of the public. The ingestion (inhalation) effective dose per unit intake integrated over one day is 1.7 × 10−8 (1.4 × 10−7) Sv Bq−1, 2.0 × 10−7 (9.6 × 10−7) Sv Bq−1 over 10 days, 5.2 × 10−7 (2.0 × 10−6) Sv Bq−1 over 30 days and 1.0 × 10−6 (3.0 × 10−6) Sv Bq−1 over 100 days. The daily urinary excretions after acute ingestion (inhalation) of 1 Bq of 210Po are 1.1 × 10−3 (1.0 × 10−4) on day 1, 2.0 × 10−3 (1.9 × 10−4) on day 10, 1.3 × 10−3 (1.7 × 10−4) on day 30 and 3.6 × 10−4 (8.3 × 10−5) Bq d−1 on day 100, respectively. The resulting committed effective doses range from 2.1 × 10−3 to 1.7 × 10−2 mSv by an assumption of ingestion and from 5.5 × 10−2 to 4.5 × 10−1 mSv by inhalation. For the case of Mr. Litvinenko, the mean organ absorbed dose as a function of time was calculated using both the above stated models. The red bone marrow, the kidneys and the liver were considered as the critical organs. Assuming a value of lethal absorbed dose of 5 Gy to the bone marrow, 6 Gy to the kidneys and 8 Gy to the liver, the amount of 210Po which Mr. Litvinenko might have ingested is therefore estimated to range from 27 to 1,408 MBq, i.e 0.2–8.5 μg, depending on the modality of intake and on different assumptions about blood absorption
A realist approach to understanding alliancing within Local Government public health and social care service provision’
Background: Within the current context of continued austerity and post pandemic recovery, it remains important that Local Government services address the increasing needs of residents as cost-effectively as possible. Alliancing, whereby services work collaboratively focusing on the ‘whole-system’, has gained popularity as a tool with the potential to support collaborative whole systems approaches. This synthesis aims to identify how alliancing can be successfully operationalised in the commissioning of public health, wider NHS, and social care related services. Methods: A realist literature synthesis was undertaken in order to identify underlying generative mechanisms associated with alliancing, the contextual conditions surrounding the implementation and operationalisation of the alliancing approach mechanisms, and the outcomes produced as a result. An iterative approach was taken, using a recent systematic review of the effectiveness of Alliancing, online database searches, and grey literature searches. Results: Three mechanistic components were identified within the data as being core to the successful implementation of alliances in public health and social care related services within Local Government: (1) Achieving a system level approach; (2) placing local populations at the heart of the system; and (3) creating a cultural shift. Programme theories were postulated within these components. Conclusions: The alliancing approach offers an opportunity to achieve system-level change with the potential to benefit local populations. The realist synthesis approach taken within this study has provided insights into the necessary contextual and mechanistic factors of the Alliancing approach, above and beyond effectiveness outcomes typically collected through more conventional evaluation methodologies
A realist approach to understanding alliancing within Local Government public health and social care service provision
Background
Within the current context of continued austerity and post-pandemic recovery, it remains important that Local Government services address the increasing needs of residents as cost-effectively as possible. Alliancing, whereby services work collaboratively focusing on the ‘whole-system’, has gained popularity as a tool with the potential to support collaborative whole systems approaches. This synthesis aims to identify how alliancing can be successfully operationalised in the commissioning of public health, wider National Health Service (NHS) and social care-related services.
Methods
A realist literature synthesis was undertaken in order to identify underlying generative mechanisms associated with alliancing, the contextual conditions surrounding the implementation and operationalisation of the alliancing approach mechanisms, and the outcomes produced as a result. An iterative approach was taken, using a recent systematic review of the effectiveness of Alliancing, online database searches, and grey literature searches.
Results
Three mechanistic components were identified within the data as being core to the successful implementation of alliances in public health and social care-related services within Local Government: (i) Achieving a system-level approach; (ii) placing local populations at the heart of the system; and (iii) creating a cultural shift. Programme theories were postulated within these components.
Conclusions
The alliancing approach offers an opportunity to achieve system-level change with the potential to benefit local populations. The realist synthesis approach taken within this study has provided insights into the necessary contextual and mechanistic factors of the Alliancing approach, above and beyond effectiveness outcomes typically collected through more conventional evaluation methodologies
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