Magnetic Switching of Phase-Slip Dissipation in NbSe2 Nanobelts

The stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanobelts is characterized by transport measurements in an external magnetic field (H). Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the critical temperature, the position of the voltage steps exhibits a sharp, periodic dependence as a function of H. This phenomenon is discussed in the context of two possible mechanisms: the interference of the order parameter and the periodic rearrangement of the vortex lattice within the nanobelt.Comment: 4 figure

Metabolites from the Marine-Derived Fungus Chromocleista sp. Isolated from a Deep-Water Sediment Sample Collected in the Gulf of Mexico

As part of our ongoing chemical investigation of biologically active metabolites from marine fungi, three new compounds, p-hydroxyphenopyrrozin (1) and diketopiperazines (3, 4), have been isolated from the marine-derived fungus Chromocleista sp. In addition, the fungus gave the known compound phenopyrrozin (2), four known diketopiperazines (6-9), N-acetyltryptamine (10), and agathic acid (11). Another new diketopiperazine (5) was separated and identified as a decomposition product of 3 and 4. The structures of the new metabolites were determined on the basis of mass spectroscopy, NMR experiments, and derivatization methods. The absolute configuration of 1 was determined by X-ray crystallography studies

Culex tarsalis is a competent vector species for Cache Valley virus

Background: Cache Valley virus (CVV) is a mosquito-borne orthobunyavirus endemic in North America. The virus is an important agricultural pathogen leading to abortion and embryonic lethality in ruminant species, especially sheep. The importance of CVV in human public health has recently increased because of the report of severe neurotropic diseases. However, mosquito species responsible for transmission of the virus to humans remain to be determined. In this study, vector competence of three Culex species mosquitoes of public health importance, Culex pipiens, Cx. tarsalis and Cx. quinquefasciatus, was determined in order to identify potential bridge vector species responsible for the transmission of CVV from viremic vertebrate hosts to humans. Results: Variation of susceptibility to CVV was observed among selected Culex species mosquitoes tested in this study. Per os infection resulted in the establishment of infection and dissemination in Culex tarsalis, whereas Cx. pipiens and Cx. quinquefasciatus were highly refractory to CVV. Detection of viral RNA in saliva collected from infected Cx. tarsalis provided evidence supporting its role as a competent vector. Conclusions: Our study provided further understanding of the transmission cycles of CVV and identifies Cx. tarsalis as a competent vector

Inhibitory effects of megakaryocytic cells in prostate cancer skeletal metastasis

Prostate cancer cells commonly spread through the circulation, but few successfully generate metastatic foci in bone. Osteoclastic cellular activity has been proposed as an initiating event for skeletal metastasis. Megakaryocytes (MKs) inhibit osteoclastogenesis, which could have an impact on tumor establishment in bone. Given the location of mature MKs at vascular sinusoids, they may be the first cells to physically encounter cancer cells as they enter the bone marrow. Identification of the interaction between MKs and prostate cancer cells was the focus of this study. K562 (human MK precursors) and primary MKs derived from mouse bone marrow hematopoietic precursor cells potently suppressed prostate carcinoma PC-3 cells in coculture. The inhibitory effects were specific to prostate carcinoma cells and were enhanced by direct cell-cell contact. Flow cytometry for propidium iodide (PI) and annexin V supported a proapoptotic role for K562 cells in limiting PC-3 cells. Gene expression analysis revealed reduced mRNA levels for cyclin D1, whereas mRNA levels of apoptosis-associated specklike protein containing a CARD (ASC) and death-associated protein kinase 1 (DAPK1) were increased in PC-3 cells after coculture with K562 cells. Recombinant thrombopoietin (TPO) was used to expand MKs in the marrow and resulted in decreased skeletal lesion development after intracardiac tumor inoculation. These novel findings suggest a potent inhibitory role of MKs in prostate carcinoma cell growth in vitro and in vivo. This new finding, of an interaction of metastatic tumors and hematopoietic cells during tumor colonization in bone, ultimately will lead to improved therapeutic interventions for prostate cancer patients. © 2011 American Society for Bone and Mineral Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78486/1/204_ftp.pd

Current Dyspnea Among Long-Term Survivors of Early-Stage Non-small Cell Lung Cancer

IntroductionDyspnea is common among lung cancer patients. As most studies of dyspnea have reviewed patients with active cancer or immediately after treatment, its prevalence during the longer-term period once treatment has been completed is not well characterized. This study quantifies the prevalence of dyspnea among lung cancer survivors and identifies potential correlates that may be amenable to intervention.MethodsCross-sectional survey of 342 patients with disease-free, stage I, non-small cell lung cancer, assessed 1 to 6 years after surgical resection. Dyspnea was quantified using the Baseline Dyspnea Index. Any moderate/strenuous physical activity was measured using the Godin Leisure-Time Exercise Questionnaire. Mood disorder symptoms were assessed using the Hospital Anxiety and Depression Scale. Multiple regression analyses were used to examine demographic, medical, and health-related correlates of dyspnea.ResultsMean age was 68.9 years. Average predicted preoperative forced expiratory volume in 1 second was 89.0%. Current dyspnea, defined by a Baseline Dyspnea Index score of 9 or less, existed among 205 (60%) individuals. For 133 (65%) of these patients, dyspnea was absent preoperatively. Multivariate correlates of current dyspnea included preoperative dyspnea (odds ratio [OR] = 5.31), preoperative diffusing capacity (OR = 0.98), lack of moderate/strenuous physical activity (OR = 0.41), and the presence of clinically significant depression symptoms (OR = 4.10).ConclusionsDyspnea is common 1 to 6 years after lung cancer resection, and is associated with the presence of preoperative dyspnea, reduced diffusing capacity, clinically significant depression symptoms, and lack of physical activity. Further research is needed to test whether strategies that identify and treat patients with these conditions attenuate dyspnea among lung cancer survivors

Fluctuation Study of the Specific Heat of MgB2

The specific heat of polycrystalline Mg$^{11}$B$_{2}$ has been measured with high resolution ac calorimetry from 5 to 45 K at constant magnetic fields. The excess specific heat above T$_{c}$ is discussed in terms of Gaussian fluctuations and suggests that Mg$^{11}$B$_{2}$ is a bulk superconductor with Ginzburg-Landau coherence length $\xi_{0}=26$ \AA . The transition-width broadening in field is treated in terms of lowest-Landau-level (LLL) fluctuations. That analysis requires that $\xi_{0}=20$ \AA . The underestimate of the coherence length in field, along with deviations from 3D LLL predictions, suggest that there is an influence from the anisotropy of B$_{c2}$ between the c-axis and the a-b plane.Comment: Phys. Rev. B 66, 134515 (2002

New Worlds Observer Optical Performance

ABSTRACT New Worlds Observer is an external occulter, or, starshade, mission designed to detect visible wavelength (less than 1 micron) light from Earth-like planets around solar neighborhood stars. A telescope spacecraft operates in the "shadow" cast by a starshade spacecraft, located tens of thousands of kilometers away. The specially contoured petals on the starshade spacecraft control the diffraction to produce high contrast suppression of the on-axis starlight. The starshade operates in the Fresnel, or near field, diffraction regime, which adds complexity to numerical simulations of its performance. As a validation of the numerical models and a demonstration of the starshade capabilities, we have built a testbed to measure the performance of subscale NWO hypergaussian starshades. We describe the rationale for our testbed and its set up. We expect to be able to report results from the testbed in a later paper this year

Projected effects of disruptions to human immunodeficiency virus (HIV) prevention services during the coronavirus disease 2019 pandemic among Black/African American men who have sex with men in an Ending the HIV Epidemic priority jurisdiction

BACKGROUND: Disruptions in access to in-person human immunodeficiency virus (HIV) preventive care during the coronavirus disease 2019 (COVID-19) pandemic may have a negative impact on our progress towards the Ending the HIV Epidemic goals in the United States. METHODS: We used an agent-based model to simulate HIV transmission among Black/African American men who have sex with men in Mississippi over 5 years to estimate how different reductions in access affected the number of undiagnosed HIV cases, new pre-exposure prophylaxis (PrEP) starts, and HIV incidence. RESULTS: We found that each additional 25% decrease in HIV testing and PrEP initiation was associated with decrease of 20% in the number of cases diagnosed and 23% in the number of new PrEP starts, leading to a 15% increase in HIV incidence from 2020 to 2022. CONCLUSIONS: Unmet need for HIV testing and PrEP prescriptions during the COVID-19 pandemic may temporarily increase HIV incidence in the years immediately after the disruption period

Infection and transmission of Cache Valley virus by Aedes albopictus and Aedes aegypti mosquitoes

Background: Cache Valley virus (CVV; Bunyavirales, Peribunyaviridae) is a mosquito-borne arbovirus endemic in North America. Although severe diseases are mainly observed in pregnant ruminants, CVV has also been recognized as a zoonotic pathogen that can cause fatal encephalitis in humans. Human exposures to CVV and its related subtypes occur frequently under different ecological conditions in the New World; however, neurotropic disease is rarely reported. High prevalence rates of neutralizing antibodies have been detected among residents in several Latin American cities. However, zoophilic mosquito species involved in the enzootic transmission are unlikely to be responsible for the transmission leading to human exposures to CVV. Mechanisms that lead to frequent human exposures to CVV remain largely unknown. In this study, competence of two anthropophilic mosquitoes, Aedes albopictus and Ae. aegypti, for CVV was determined using per os infection to determine if these species could play a role in the transmission of CVV in the domestic and peridomestic settings of urban and suburban areas. Results: Aedes albopictus were highly susceptible to CVV whereas infection of Ae. aegypti occurred at a significantly lower frequency. Whilst the dissemination rates of CVV were comparable in the two species, the relatively long period to attain maximal infectious titer in Ae. aegypti demonstrated a significant difference in the replication kinetics of CVV in these species. Detection of viral RNA in saliva suggests that both Ae. albopictus and Ae. aegypti are competent vectors for CVV under laboratory conditions. Conclusions: Differential susceptibility to CVV was observed in Ae. albopictus and Ae. aegypti, reflecting their relatively different capacities for vectoring CVV in nature. The high susceptibility of Ae. albopictus to CVV observed in this study suggests its potential role as an efficient vector for CVV. Complemented by the reports of multiple CVV isolates derived from Ae. albopictus, our finding provides the basis for how the dispersal of Ae. albopictus across the New World may have a significant impact on the transmission and ecology of CVV