Measuring Bacterial Growth Using a 3D-Printable Spectrometer

Visible light spectroscopy is a commonly used technique for measuring the growth of bacterial cultures, and growth curves provide broadly important data. However, the equipment and resources required for these experiments has been restricted to higher education and industry due to high cost and sophistication. We have previously reported on an inexpensive, 3D-printable photospectrometer called the SpecPhone. This device utilizes an iPhone as the camera, along with several other, inexpensive additions to make a fully functional spectrometer. Here, the application of the SpecPhone is expanded to the quantification of actively dividing E. coli cultures. Two protocols have been developed; one describes a culture grown in a beaker and the second is a downsized culture grown entirely in a plastic cuvette. These protocols provide hands-on teaching opportunities for the use of spectroscopy to measure bacterial growth, and to do so in educational situations that lack the resources of a higher learning institution or industry

Targeting genes for self-excision in the germ line

Journal ArticleA procedure is described that directs the self-induced deletion of DNA sequences as they pass through the male germ line of mice. The testes-specific promoter from the angiotensin-converting enzyme gene was used to drive expression of the Cre-recombinase gene. Cre was linked to the selectable marker Neor, and the two genes flanked with loxP elements. This cassette was targeted to the Hoxa3 gene in mouse ES cells that were in turn used to generate chimeric mice. In these chimeras, somatic cells derived from the ES cells retained the cassette, but self-excision occurred in all ES-cell-derived sperm

Transforming growth factor beta (TGF beta) mediates schwann cell death in vitro and in vivo: Examination of c-jun activation, interactions with survival signals, and the relationship of TGF beta-mediated death to schwann cell differentiation

In some situations, cell death in the nervous system is controlled by an interplay between survival factors and negative survival signals that actively induce apoptosis. The present work indicates that the survival of Schwann cells is regulated by such a dual mechanism involving the negative survival signal transforming growth factor beta (TGF beta), a family of growth factors that is present in the Schwann cells themselves. We analyze the interactions between this putative autocrine death signal and previously defined paracrine and autocrine survival signals and show that expression of a dominant negative c-Jun inhibits TGF beta -induced apoptosis. This and other findings pinpoint activation of c-Jun as a key downstream event in TGF beta -induced Schwann cell death. The ability of TGF beta to kill Schwann cells, like normal Schwann cell death in vivo, is under a strong developmental regulation, and we show that the decreasing ability of TGF beta to kill older cells is attributable to a decreasing ability of TGF beta to phosphorylate c-Jun in more differentiated cells

Shock Tube Study of the Thermal Conductivity of Argon

Analysis of end-wall thermal boundary layer behind reflected shock to determine thermal conductivity of argon over temperatures 3150 to 9225

Operational large-scale segmentation of imagery based on iterative elimination

Image classification and interpretation are greatly aided through the use of image segmentation. Within the field of environmental remote sensing, image segmentation aims to identify regions of unique or dominant ground cover from their attributes such as spectral signature, texture and context. However, many approaches are not scalable for national mapping programmes due to limits in the size of images that can be processed. Therefore, we present a scalable segmentation algorithm, which is seeded using k-means and provides support for a minimum mapping unit through an innovative iterative elimination process. The algorithm has also been demonstrated for the segmentation of time series datasets capturing both the intra-image variation and change regions. The quality of the segmentation results was assessed by comparison with reference segments along with statistics on the inter- and intra-segment spectral variation. The technique is computationally scalable and is being actively used within the national land cover mapping programme for New Zealand. Additionally, 30-m continental mosaics of Landsat and ALOS-PALSAR have been segmented for Australia in support of national forest height and cover mapping. The algorithm has also been made freely available within the open source Remote Sensing and GIS software Library (RSGISLib)

UK National Audit of Early Syphilis Management. Case notes audit: diagnosis and treatment

A national audit of 781 early syphilis cases presenting during 2002–03 in UK genitourinary medicine clinics was conducted in late 2004, organized through the Regional Audit Groups. Data were aggregated by region and National Health Service trust, allowing practice to be compared between regions, between trusts within regions, as well as to national averages and the UK National Guidelines. An enzyme immunoassay was used to diagnose 695 (89%) cases (regional range 18–100%). Use of a non-treponemal test was not recorded for 44 (6%) cases. Dark ground microscopy was used in the diagnosis of only 80 (29%) primary cases. Uptake of HIV testing was 77% (range 69–94%). Nationally, 527 (67%) treatments were parenteral, with almost equal use of benzathine penicillin G for 262 (50%, range 0–97%) cases and procaine penicillin G (PPG) for 260 cases (49%, range 3–100%). There were 14 (5%) treatments with less than the recommended 750 mg dose of PPG. One hundred and five (40%) PPG treatments were with greater than 750 mg and/or for longer than 10 days of which 76 (72%) were for early latent syphilis and/or cases with HIV infection. One hundred and ninety two (86%, range 0–100%) of all oral treatments were with doxycycline. The recommended regimen of 100 mg doxycycline twice daily for 14 days was used for 104 (53%) cases; the other 91 (47%) treatments were with a variety of regimens, mainly treatments with larger doses and/or longer treatment intervals and some combination treatments. Fourteen (2%) cases were not treated; treatment was not reported for seven (0.9%) and not known for 10 (1.3%) cases, who were treated at other centres

UK National Audit of Early Syphilis Management. Clinics audit: screening for and management of early syphilis

Data were provided by 131 clinics, and 56% of cases were managed in clinics in the London regions in 2003. Three clinics (2%) do not routinely screen new patients for syphilis, and 28 clinics (21%) do not routinely screen ‘rebook’ patients who have had a new partner. More than 80% of clinics routinely conduct cardiovascular and neurological examinations, although chest radiography is only performed by 50% of clinics and lumbar puncture by 13%. Only 19 (14%) clinics indicated not routinely using the recommended procaine penicillin G (PPG) regimen or one- or two-dose benzathine penicillin G (BPG) regimens for early syphilis, with 57% providing two doses of BPG 2.4 g, 40% providing PPG 750 mg for 10 days, and 15% providing one dose of BPG 2.4 g. Only seven clinics (5%) indicated that they provided treatment for early syphilis with PPG that is inferior to that recommended in the national guidelines. Only 18 clinics specified using the recommended dose and duration (or in excess of this) of PPG for neurosyphilis for cases with HIV infection. Provision for management of severe penicillin reaction is good, although few patients are desensitized. All clinics report that contact tracing for early syphilis is provided, and is mainly the responsibility of health advisers. Compared with auditing outcomes, audit of management policies overestimated performance in contact tracing and provision of dark ground microscopy

Optimization of the visibility of graphene on poly-Si film by thin-film optics engineering

A multilayer optical system containing poly-Si film, SiO 2 film, and Si substrate (poly-Si substrate) has been designed to enhance the visibility of graphene in contact with poly-Si. Film thicknesses of poly-Si and SiO 2 have been optimized by parametric study of the integral contrast of single layer graphene using transfer matrix theory. The multilayer poly-Si substrate and the most commonly used 285 nm SiO 2 /Si substrate (SiO 2 substrate) have been fabricated. Graphene grown by chemical vapor deposition on Ni catalyst has been transferred to the substrates and the visibility of the graphene on the different substrates has been compared. The samples have been characterized by optical microscope, illuminated with light from halogen lamp, and/or filtered with a 600 nm narrow band optical filter. The contrast of graphene on poly-Si substrate has been increased to near 8.7 under 600 nm narrow band illumination from nearly invisible under ordinary illumination, while the contrast of graphene on SiO 2 remains almost the same. Raman spectroscopy has been used to verify the presence of the single layer graphene on the poly-Si substrate.</p

UK National Audit of Early Syphilis Management. Case-notes audit: contact tracing, information giving, follow-up and outcomes

Contact tracing was provided for 683/781 (87%, regional range 57–97%) cases, and identified 997 traceable contacts of whom 511 (51%) were seen, short of the recommended standard of 60%. However, the performance range for this standard was 26–70%, with seven regions achieving 60% or more. Of 511, 215 (42%, range 3–73%) contacts had syphilis. Treatment completion was recorded for 691 (88%, range 71–100%) cases, and resolution of lesions for 348/469 (74%, range 40–96%) cases. Nationally, 419/764 (55%, range 37–70%) cases were recorded as having a two dilution (four-fold) or greater decrease in non-treponemal test titre within 3–6 months after treatment; not achieving this titre decrease was mainly attributable to non-attendance for follow-up and failure of titre levels to fall. Follow-up of infectious syphilis in UK genitourinary medicine clinics is poor and falls far short of that recommended by National Guidelines. Only 16 (2%) cases had follow-up at intervals approximating to 1, 2, 3, 6 and 12 months, and only 312 (40%, range 5–61%) cases attended at least two follow-up visits. Only 17 (7%) of all 236 oral treatments (including switches to oral treatment), and 33 (27%) of 123 cases with HIV infection were recorded as designated annual follow-up. Further work is needed to determine factors that account for the wide variation between regions in contact tracing and follow-up performance