Instrumented fusion of thoracolumbar fracture with type I mineralized collagen matrix combined with autogenous bone marrow as a bone graft substitute: a four-case report

In order to avoid the morbidity from autogenous bone harvesting, bone graft substitutes are being used more frequently in spinal surgery. There is indirect radiological evidence that bone graft substitutes are efficacious in humans. The purpose of this four-case study was to visually, manually, and histologically assess the quality of a fusion mass produced by a collagen hydroxyapatite scaffold impregnated with autologous bone marrow aspirate for posterolateral fusion. Four patients sustained an acute thoracolumbar fracture and were treated by short posterior segment fusion using the AO fixateur interne. Autologous bone marrow (iliac crest) impregnated hydroxyapatite-collagen scaffold was laid on the decorticated posterior elements. Routine implant removal was performed after a mean of 15.3months (12-20). During this second surgery, fusion mass was assessed visually and manually. A bone biopsy was sent for histological analysis of all four cases. Fusion was confirmed in all four patients intraoperatively and sagittal stress testing confirmed mechanical adequacy of the fusion mass. Three out of the four (cases 2-4) had their implants removed between 12 and 15months after the index surgery. All their histological cuts showed evidence of newly formed bone and presence of active membranous and/or enchondral ossification foci. The last patient (case 1) underwent implant removal at 20months and his histological cuts showed mature bone, but no active ossification foci. This four-case report suggests that the fusion mass produced by a mineralized collagen matrix graft soaked in aspirated bone marrow is histologically and mechanically adequate in a thoracolumbar fracture model. A larger patient series and/or randomized controlled studies are warranted to confirm these initial result

Text Conditional Alt-Text Generation for Twitter Images

In this work we present an approach for generating alternative text (or alt-text) descriptions for images shared on social media, specifically Twitter. This task is more than just a special case of image captioning, as alt-text is both more literally descriptive and context-specific. Also critically, images posted to Twitter are often accompanied by user-written text that despite not necessarily describing the image may provide useful context that if properly leveraged can be informative -- e.g. the tweet may name an uncommon object in the image that the model has not previously seen. We address this with a CLIP prefix model that extracts an embedding of the image and passes it to a mapping network that outputs a short sequence in word embedding space, or a ``prefix'', to which we also concatenate the text from the tweet itself. This lets the model condition on both visual and textual information from the post. The combined multimodal prefix is then fed as a prompt to a pretrained language model which autoregressively completes the sequence to generate the alt-text. While prior work has used similar methods for captioning, ours is the first to our knowledge that incorporates textual information from the associated social media post into the prefix as well, and we further demonstrate through ablations that utility of these two information sources stacks. We put forward a new dataset scraped from Twitter and evaluate on it across a variety of automated metrics as well as human evaluation, and show that our approach of conditioning on both tweet text and visual information significantly outperforms prior work

MS-1 magA: Revisiting Its Efficacy as a Reporter Gene for MRI

Bacterial genes involved in the biomineralization of magnetic nanoparticles in magnetotactic bacteria have recently been proposed as reporters for magnetic resonance imaging (MRI). In such systems, the expression of the bacterial genes in mammalian cells purportedly leads to greater concentrations of intracellular iron or the biomineralization of iron oxides, thus leading to an enhancement in relaxation rate that is detectable via MRI. Here, we show that the constitutive expression of the magA gene from Magnetospirillum magnetotacticum is tolerated by human embryonic kidney (HEK) cells but induces a strong toxic effect in murine mesenchymal/stromal cells and kidney-derived stem cells, severely restricting its effective use as a reporter gene for stem cells. Although it has been suggested that magA is involved in iron transport, when expressed in HEK cells, it does not affect the transcription of endogenous genes related to iron homeostasis. Furthermore, the magA -induced enhancement in iron uptake in HEK cells is insignificant, suggesting this gene is a poor reporter even for cell types that can tolerate its expression. We suggest that the use of magA for stem cells should be approached with caution, and its efficacy as a reporter gene requires a careful assessment on a cell-by-cell basis

Does Student Engagement Have a Darkside?

Academic misconduct is a growing problem on college campuses. A student’s academic life on campus can take a dark turn if a student does not manage their workload, engagement, or time management well. These variables can overlap if a student is overwhelmed, under-engaged, and busy. A heavy workload can result in a lack of engagement at a student’s institution. Institutions can help students develop strategies that provide a foundation for healthy engagement habits that work against academic dishonesty. Academic success can be affected by students’ time management skills in mitigating the effects of time pressure. Institutions can help students combat a heavy workload with academic campus resources such as writing centers, peer mentors, and advising. These variables can then lead to a student engaging in academic misconduct if they are under-engaged, overly busy, and have poor time management skills

Chemistry of dense clumps near moving Herbig-Haro objects

Localised regions of enhanced emission from HCO+, NH3 and other species near Herbig-Haro objects (HHOs) have been interpreted as arising in a photochemistry stimulated by the HHO radiation on high density quiescent clumps in molecular clouds. Static models of this process have been successful in accounting for the variety of molecular species arising ahead of the jet; however recent observations show that the enhanced molecular emission is widespread along the jet as well as ahead. Hence, a realistic model must take into account the movement of the radiation field past the clump. It was previously unclear as to whether the short interaction time between the clump and the HHO in a moving source model would allow molecules such as HCO+ to reach high enough levels, and to survive for long enough to be observed. In this work we model a moving radiation source that approaches and passes a clump. The chemical picture is qualitatively unchanged by the addition of the moving source, strengthening the idea that enhancements are due to evaporation of molecules from dust grains. In addition, in the case of several molecules, the enhanced emission regions are longer-lived. Some photochemically-induced species, including methanol, are expected to maintain high abundances for ~10,000 years.Comment: 7 pages, 3 figure

California Test System (CATS): A Geographically Accurate Test System based on the California Grid

This paper presents the California Test System (CATS), a synthetic transmission grid in California that can be used by the public for power systems research without revealing any critical energy information. The proposed synthetic grid combines publicly available geographic data of California's electric infrastructure, such as the actual location of transmission corridors, with invented topology and transmission line parameters that are "realistic but not real". The result is a test system that is suitable for power flow and optimal power flow analysis. The methods used to develop and evaluate the CATS grid are documented in detail in this report.Comment: 10 pages, 7 figure

Synthesis and Evaluation of Nifurtimox-Adamantane Adducts with Trypanocidal Activity.

The synthesis and pharmacological evaluation of C1-substituted adamantane hydrazones, their C2-substituted isomers, and C1-substituted adamantane furanoic carboxamides is described. These new adamantane derivatives exhibited an interesting pharmacological profile in terms of trypanocidal activity and selectivity. The most active adduct with the best selectivity in this study was found to be the phenylacetoxy hydrazone 1 b (2-[4-(tricyclo[3.3.1.13,7 ]dec-1-yl)phenyl]-N'-[(5-nitrofuran-2-yl)methylene]acetohydrazide; EC50 =11±0.9 nm, SITb =770)

The host galaxies of three radio-loud quasars: 3C 48, 3C 345, and B2 1425+267

Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space Telescope (HST) are presented for three radio-loud quasars: 3C 48 (z=0.367), B2 1425+267 (z=0.366), and 3C 345 (z=0.594). All three quasars have luminous (~4 L^*) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C 345) or interacting (3C 48), and all hosts are 0.5 - 1.0 mag bluer in (V-I) than other galaxies with the same overall morphology at similar redshifts to the quasars. The host of 3C 48 has many H II regions and a very extended tidal tail. All nine of the radio-loud quasars studied here and in Bahcall et al. (1997) either have bright elliptical hosts or occur in interacting systems. There is a robust correlation between the radio emission of the quasar and the luminosity of host galaxy; the radio-loud quasars reside in galaxies that are on average about 1 mag brighter than hosts of the radio-quiet quasars.Comment: Accepted for publication in ApJ. 3 postscript and 3 jpeg figures. Original figures may be found in ftp://eku.sns.ias.edu/pub/sofia/RadioLoud