3,014 research outputs found

    Enthusiastic Jew and Lover of Humanity : August Bondi and the Roots of Transnational Freedom during the Long Nineteenth Century

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    Migration is a decidedly human condition that has influenced the development of all nations. Yet the cultural and demographic impacts upon the United States during the long nineteenth century brought about by the mass movements of peoples from Africa, Europe, and beyond were especially pronounced. Immigrants to North America brought with them more than linguistic and cultural artifacts, however; propelled by intellectual currents in their countries of origin, they often carried with them a sensibility of revolution, radical republican politics, and a moral suasion that they employed as they navigated the political and social realities in their new countries. Many immigrants would come to view America and the New World generally through a prism of their own making, and thus see opportunity to dismantle and remake the world – economically, socially, culturally, and politically – when conditions at home had failed them. Two fundamental events shaped this trans-Atlantic consciousness situated toward revolution during the nineteenth century: the European Revolutions of 1848-51, and an increasingly radical anti-slavery and abolitionist movement in the United States during the lead-up to sectional conflict and the Civil War. Both events sought to upend the established order through political, social, and cultural revolution, and both came to reinforce one another intellectually and strategically. Both revolutions sought to attack the existing systems – monarchy, capital, and the legal institutions that upheld slavery – and replace them, in the spirit of revolutions prior, with more egalitarian and liberal structures. Immigrants were often the main vehicles of this transnational cooperation. When it became clear to freedom fighters on both sides of the Atlantic that moral and political gradualism toward parliamentary, democratic systems of governance, or toward anti-slavery and abolitionist movements, were to be ineffective, they would turn to markedly more radical approaches, and sometimes to violence to enact the changes they sought. This paper investigates these broad trends through the individuals who personally lived them. One such figure, August (Anshl) Mendel Bondi, was a German-speaking, Hungarian Jew who participated in the revolutionary events in Vienna. Upon the restoration of the Hapsburg Monarchy, Bondi would be forced to flee with his family to the United States. Forging a new life in his new home, he would variously spend time in Louisiana and Texas, and work as a waterman on the Mississippi River. Eventually he would settle in Kansas Territory, where he became radicalized and joined Free Soilers in their fight against pro-slavery forces and Missouri border ruffians. Riding with John Brown during the Bleeding Kansas episode would inspire Bondi to a lifetime of freedom fighting; he and his eventual wife, Henrietta Einstein, another German-speaking immigrant from Bavaria, would be pivotal in establishing stops along the Underground Railroad

    Metropolitan quantum key distribution with silicon photonics

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    Photonic integrated circuits (PICs) provide a compact and stable platform for quantum photonics. Here we demonstrate a silicon photonics quantum key distribution (QKD) transmitter in the first high-speed polarization-based QKD field tests. The systems reach composable secret key rates of 950 kbps in a local test (on a 103.6-m fiber with a total emulated loss of 9.2 dB) and 106 kbps in an intercity metropolitan test (on a 43-km fiber with 16.4 dB loss). Our results represent the highest secret key generation rate for polarization-based QKD experiments at a standard telecom wavelength and demonstrate PICs as a promising, scalable resource for future formation of metropolitan quantum-secure communications networks

    Accurate Assignments of Excited-State Resonance Raman Spectra: A Benchmark Study Combining Experiment and Theory

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    This is an unofficial translation of an article that appeared in an ACS publication. ACS has not endorsed the content of this translation or the context of its use.Femtosecond stimulated Raman scattering (FSRS) probes the structural dynamics of molecules in electronically excited states by following the evolution of the vibrational spectrum. Interpreting the dynamics requires accurate assignments to connect the vibrational bands with specific nuclear motions of an excited molecule. However, the assignment of FSRS signals is often complicated by mode-specific resonance enhancement effects that are difficult to calculate for molecules in electronically excited states. We present benchmark results for a series of eight aryl-substituted thiophene derivatives to show that calculated off-resonance Raman spectra can be used to assign experimental bands on the basis of a comparison of structurally similar compounds and careful consideration of the resonance condition. Importantly, we show that direct comparison with the off-resonant calculations can lead to incorrect assignments of the experimental spectrum if the resonance condition is neglected. These results highlight the importance of resonance enhancement effects in assigning FSRS spectra

    Frank-Read Mechanism in Nematic Liquid Crystals

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    In a crystalline solid under mechanical stress, a Frank-Read source is a pinned dislocation segment that repeatedly bows and detaches, generating concentric dislocation loops. We demonstrate that in nematic liquid crystals, an analogous Frank-Read mechanism can generate concentric disclination loops. Using experiment, simulation, and theory, we study a disclination segment pinned between surface defects on one substrate in a nematic cell. Under applied twist of the nematic director, the pinned segment bows and emits a new disclination loop which expands, leaving the original segment intact; loop emission repeats for each additional 180∘^\circ of applied twist. We present experimental micrographs showing loop expansion and snap-off, numerical simulations of loop emission under both quasistatic and dynamic loading, and theoretical analysis considering both free energy minimization and the balance of competing forces. We find that the critical stress for disclination loop emission scales as the inverse of segment length, and changes as a function of strain rate and temperature, in close analogy to the Frank-Read source mechanism in crystals. Lastly, we discuss how Frank-Read sources could be used to modify microstructural evolution in both passive and active nematics.Comment: 29 pages, 6 figure

    Medication Utilization and the Impact of Continued Corticosteroid Use on Patient-reported Outcomes in Older Patients with Inflammatory Bowel Disease:

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    Older individuals with inflammatory bowel disease (IBD) require ongoing medications. We aimed to describe 1) medication use in older and younger IBD patients and 2) medication associations with patient reported outcomes (PRO’s) in older patients

    Increased instantaneous bandwidth of Rydberg atom electrometry with an optical frequency comb probe

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    We show that the use of an optical frequency comb probe leads to dramatically improved bandwidth (as high as 12+/-1 MHz) for the detection of modulated radio frequencies in Rydberg atom-based electrometry

    Peptidoglycan synthesis in Mycobacterium tuberculosis is organized into networks with varying drug susceptibility

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    Peptidoglycan (PG), a complex polymer composed of saccharide chains cross-linked by short peptides, is a critical component of the bacterial cell wall. PG synthesis has been extensively studied in model organisms but remains poorly understood in mycobacteria, a genus that includes the important human pathogen Mycobacterium tuberculosis (Mtb). The principle PG synthetic enzymes have similar and, at times, overlapping functions. To determine how these are functionally organized, we carried out whole-genome transposon mutagenesis screens in Mtb strains deleted for ponA1, ponA2, and ldtB, major PG synthetic enzymes. We identified distinct factors required to sustain bacterial growth in the absence of each of these enzymes. We find that even the homologs PonA1 and PonA2 have unique sets of genetic interactions, suggesting there are distinct PG synthesis pathways in Mtb. Either PonA1 or PonA2 is required for growth of Mtb, but both genetically interact with LdtB, which has its own distinct genetic network. We further provide evidence that each interaction network is differentially susceptible to antibiotics. Thus, Mtb uses alternative pathways to produce PG, each with its own biochemical characteristics and vulnerabilities

    DHODH modulates transcriptional elongation in the neural crest and melanoma

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    Melanoma is a tumour of transformed melanocytes, which are originally derived from the embryonic neural crest. It is unknown to what extent the programs that regulate neural crest development interact with mutations in the BRAF oncogene, which is the most commonly mutated gene in human melanoma1. We have used zebrafish embryos to identify the initiating transcriptional events that occur on activation of human BRAF(V600E) (which encodes an amino acid substitution mutant of BRAF) in the neural crest lineage. Zebrafish embryos that are transgenic for mitfa:BRAF(V600E) and lack p53 (also known as tp53) have a gene signature that is enriched for markers of multipotent neural crest cells, and neural crest progenitors from these embryos fail to terminally differentiate. To determine whether these early transcriptional events are important for melanoma pathogenesis, we performed a chemical genetic screen to identify small-molecule suppressors of the neural crest lineage, which were then tested for their effects on melanoma. One class of compound, inhibitors of dihydroorotate dehydrogenase (DHODH), for example leflunomide, led to an almost complete abrogation of neural crest development in zebrafish and to a reduction in the self-renewal of mammalian neural crest stem cells. Leflunomide exerts these effects by inhibiting the transcriptional elongation of genes that are required for neural crest development and melanoma growth. When used alone or in combination with a specific inhibitor of the BRAF(V600E) oncogene, DHODH inhibition led to a marked decrease in melanoma growth both in vitro and in mouse xenograft studies. Taken together, these studies highlight developmental pathways in neural crest cells that have a direct bearing on melanoma formation

    Prevalence and Associations between Food Insecurity and Overweight/Obesity among Native Hawaiian and Pacific Islander Adolescents

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    Abstract Objective: This study estimates the prevalence of, and associations between, family food insecurity and overweight/obesity among Native Hawaiian and Pacific Islander (NHPI) adolescents and explores sociodemographic factors which might have a moderation effect on the association. Design: Cross-sectional study using 2014 NHPI-National Health Interview Survey (NHIS) data reported by a parent or guardian. Family-level food security was assessed by the United States (US) Department of Agriculture 10-item questionnaire. BMI for age and sex >=85th and 95th percentiles defined overweight and obesity, respectively, according to US Centers for Disease Control and Prevention criteria. Setting: The US, including all 50 states and the District of Columbia. Participants: 383 NHPI adolescents aged 12-17 in the US. Results: A third (33.5%) of NHPI adolescents aged 12-17 were overweight (19.1%) or obese (14.4%); 8.1% had low food security; and 8.5% had very low food security. Mean family food security score was 1.06, which corresponds to marginal food security. We found no association between family food insecurity and adolescent overweight/obesity or between any other covariates and overweight/obesity, except for family Supplemental Nutrition Assistance Program (SNAP) participation. Odds of being overweight/obese were 77% lower for adolescents in families participating in SNAP (OR: 0.23, 95% CI: 0.08-0.64, p=0.007). The association between SNAP participation and lower odds of overweight/obesity was particularly pronounced for adolescent girls in food insecure families. Conclusions: The association between SNAP participation and lower odds of overweight/obesity suggests potential benefit of research to determine whether interventions to increase SNAP enrollment would improve NHPI adolescents’ health outcomes

    Does prior acute exercise affect postexercise substrate oxidation in response to a high carbohydrate meal?

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    <p>Abstract</p> <p>Background</p> <p>Consumption of a mixed meal increases postprandial carbohydrate utilization and decreases fat oxidation. On the other hand, acute endurance exercise increases fat oxidation and decreases carbohydrate utilization during the post-exercise recovery period. It is possible that the resulting post-exercise increase in circulating nonesterified fatty acids could attenuate the ability of ingested carbohydrate to inhibit lipid oxidation. The purpose of this study was to determine whether prior exercise attenuates the usual meal-induced decline in lipid oxidation.</p> <p>Methods</p> <p>Six healthy, physically active young subjects (x age = 26.3 years, 4 males, 2 females) completed three treatments in random order after a ~10 h fast: (a) Exercise/Carbohydrate (Ex/CHO) – subjects completed a bout of exercise at 70% VO<sub>2peak </sub>(targeted net energy cost of 400 kcals), followed by consumption of a carbohydrate-rich meal; (b) Exercise/Placebo (Ex/Placebo) – subjects completed an identical bout of exercise followed by consumption of a placebo; and (c) No Exercise/Carbohydrate (NoEx/CHO) – subjects sat quietly rather than exercising and then consumed the carbohydrate-rich meal. Blood samples were obtained before and during the postprandial period to determine plasma glucose, insulin, and non-esterified fatty acids (NEFA). Respiratory gas exchange measures were used to estimate rates of fat and carbohydrate oxidation.</p> <p>Results</p> <p>Plasma NEFA were approximately two-fold higher immediately following the two exercise conditions compared to the no-exercise condition, while meal consumption significantly increased insulin and glucose in both Ex/CHO and NoEx/CHO. NEFA concentrations fell rapidly during the 2-h postprandial period, but remained higher compared to the NoEx/CHO treatment. Carbohydrate oxidation increased rapidly and fat oxidation decreased in response to the meal, with no differences in the rates of carbohydrate and fat oxidation during recovery between the Ex/CHO and NoEx/CHO conditions.</p> <p>Conclusion</p> <p>The plasma NEFA concentration is increased during the post exercise period, which is associated with elevated fat oxidation when no meal is consumed. However, when a mixed meal is consumed immediately following exercise, the initially elevated plasma NEFA concentration decreases rapidly, and postexercise fat oxidation during this 2-h postexercise, postprandial period is no higher than that of the 2-h postprandial period without prior exercise.</p
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