491 research outputs found
Minimum energy path for the nucleation of misfit dislocations in Ge/Si(001) heteroepitaxy
A possible mechanism for the formation of a 90{\deg} misfit dislocation at
the Ge/Si(001) interface through homogeneous nucleation is identified from
atomic scale calculations where a minimum energy path connecting the coherent
epitaxial state and a final state with a 90{\deg} misfit dislocation is found
using the nudged elastic band method. The initial path is generated using a
repulsive bias activation procedure in a model system including 75000 atoms.
The energy along the path exhibits two maxima in the energy. The first maximum
occurs as a 60{\deg} dislocation nucleates. The intermediate minimum
corresponds to an extended 60{\deg} dislocation. The subsequent energy maximum
occurs as a second 60{\deg} dislocation nucleates in a complementary, mirror
glide plane, simultaneously starting from the surface and from the first
60{\deg} dislocation. The activation energy of the nucleation of the second
dislocation is 30% lower than that of the first one showing that the formation
of the second 60{\deg} dislocation is aided by the presence of the first one.
The simulations represent a step towards unraveling the formation mechanism of
90{\deg} dislocations, an important issue in the design of growth procedures
for strain released Ge overlayers on Si(100) surfaces, and more generally
illustrate an approach that can be used to gain insight into the mechanism of
complex nucleation paths of extended defects in solids
Hepatocellular Carcinoma with Immature T-Cell (T-lymphoblastic) Proliferation
Indolent T-lymphoblastic proliferation has been rarely reported in the upper aerodigestive tract. The lymphoid cells associated with this condition have the morphological and phenotypical features of immature thymocytes. However, their pathogenesis and biology are unknown. We present an unusual type of tumor infiltrating lymphocytes in a case with hepatocellular carcinoma, presumed to be a T-lymphoblastic proliferation. A 58-yr-old female patient presented with indigestion and a palpable epigastric mass. The abdominal computed tomography revealed a mass in the S6 region of the liver. A hepatic segmentectomy was performed. Microscopic examination showed dense isolated nests of monomorphic lymphoid cells within the tumor. Immunohistochemically, the lymphoid cells were positive for CD3, terminal deoxymucleotide transferase (TdT) and CD1a. In addition, they showed dual expression of CD4 and CD8. The polymerase chain reaction used to examine the T-cell antigen receptor gamma gene rearrangement showed polyclonal T-cell proliferation. This is the second case of hepatocellular carcinoma combined with indolent T-lymphoblastic proliferation identified by an unusual tumor infiltrating lymphocytes
Projections of Ebola outbreak size and duration with and without vaccine use in Ăquateur, Democratic Republic of Congo, as of May 27, 2018.
As of May 27, 2018, 6 suspected, 13 probable and 35 confirmed cases of Ebola virus disease (EVD) had been reported in Ăquateur Province, Democratic Republic of Congo. We used reported case counts and time series from prior outbreaks to estimate the total outbreak size and duration with and without vaccine use. We modeled Ebola virus transmission using a stochastic branching process model that included reproduction numbers from past Ebola outbreaks and a particle filtering method to generate a probabilistic projection of the outbreak size and duration conditioned on its reported trajectory to date; modeled using high (62%), low (44%), and zero (0%) estimates of vaccination coverage (after deployment). Additionally, we used the time series for 18 prior Ebola outbreaks from 1976 to 2016 to parameterize the Thiel-Sen regression model predicting the outbreak size from the number of observed cases from April 4 to May 27. We used these techniques on probable and confirmed case counts with and without inclusion of suspected cases. Probabilistic projections were scored against the actual outbreak size of 54 EVD cases, using a log-likelihood score. With the stochastic model, using high, low, and zero estimates of vaccination coverage, the median outbreak sizes for probable and confirmed cases were 82 cases (95% prediction interval [PI]: 55, 156), 104 cases (95% PI: 58, 271), and 213 cases (95% PI: 64, 1450), respectively. With the Thiel-Sen regression model, the median outbreak size was estimated to be 65.0 probable and confirmed cases (95% PI: 48.8, 119.7). Among our three mathematical models, the stochastic model with suspected cases and high vaccine coverage predicted total outbreak sizes closest to the true outcome. Relatively simple mathematical models updated in real time may inform outbreak response teams with projections of total outbreak size and duration
The role of geographical proximity in the establishment and development of science parks â evidence from Nanjing, China
The emergence of science parks is a relatively new phenomenon in China. Apart from the widely debated topics of universityâindustry linkages, collaboration among firms and spontaneous/policy-driven science parks, the development of science parks in China also has several distinguishing characteristics, such as their ambiguous linkage with urban expansion and their hierarchical structuring pattern. This paper attempts to discuss the motivation and efficiency of spatial proximity in science park development and to explore the role of universities in science parks, the function of science parks as a government project and a case study of location choice by on-site firms. The qualitative analysis, based on in-depth interviews with tenant firm managers and district-level government officers in Jiangning, Nanjing, is used as a basis for discussion
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SAHA Enhances Synaptic Function and Plasticity In Vitro but Has Limited Brain Availability In Vivo and Does Not Impact Cognition
Suberoylanilide hydroxamic acid (SAHA) is an inhibitor of histone deacetylases (HDACs) used for the treatment of cutaneous T cell lymphoma (CTCL) and under consideration for other indications. In vivo studies suggest reducing HDAC function can enhance synaptic function and memory, raising the possibility that SAHA treatment could have neurological benefits. We first examined the impacts of SAHA on synaptic function in vitro using rat organotypic hippocampal brain slices. Following several days of SAHA treatment, basal excitatory but not inhibitory synaptic function was enhanced. Presynaptic release probability and intrinsic neuronal excitability were unaffected suggesting SAHA treatment selectively enhanced postsynaptic excitatory function. In addition, long-term potentiation (LTP) of excitatory synapses was augmented, while long-term depression (LTD) was impaired in SAHA treated slices. Despite the in vitro synaptic enhancements, in vivo SAHA treatment did not rescue memory deficits in the Tg2576 mouse model of Alzheimerâs disease (AD). Along with the lack of behavioral impact, pharmacokinetic analysis indicated poor brain availability of SAHA. Broader assessment of in vivo SAHA treatment using high-content phenotypic characterization of C57Bl6 mice failed to demonstrate significant behavioral effects of up to 150 mg/kg SAHA following either acute or chronic injections. Potentially explaining the low brain exposure and lack of behavioral impacts, SAHA was found to be a substrate of the blood brain barrier (BBB) efflux transporters Pgp and Bcrp1. Thus while our in vitro data show that HDAC inhibition can enhance excitatory synaptic strength and potentiation, our in vivo data suggests limited brain availability may contribute to the lack of behavioral impact of SAHA following peripheral delivery. These results do not predict CNS effects of SAHA during clinical use and also emphasize the importance of analyzing brain drug levels when interpreting preclinical behavioral pharmacology
A phase II single-arm study of pembrolizumab with enzalutamide in men with metastatic castration-resistant prostate cancer progressing on enzalutamide alone.
BACKGROUND: Checkpoint inhibitors can induce profound anticancer responses, but programmed cell death protein-1 (PD-1) inhibition monotherapy has shown minimal activity in prostate cancer. A published report showed that men with prostate cancer who were resistant to the second-generation androgen receptor inhibitor enzalutamide had increased programmed death-ligand 1 (PD-L1) expression on circulating antigen-presenting cells. We hypothesized that the addition of PD-1 inhibition in these patients could induce a meaningful cancer response.
METHODS: We evaluated enzalutamide plus the PD-1 inhibitor pembrolizumab in a single-arm phase II study of 28 men with metastatic castration-resistant prostate cancer (mprogressing on enzalutamide alone. Pembrolizumab 200âmg intravenous was given every 3âweeks for four doses with enzalutamide. The primary endpoint was prostate-specific antigen (PSA) decline of â„50%. Secondary endpoints were objective response, PSA progression-free survival (PFS), time to subsequent treatment, and time to death. Baseline tumor biopsies were obtained when feasible, and samples were sequenced and evaluated for the expression of PD-L1, microsatellite instability (MSI), mutational and neoepitope burdens.
RESULTS: Five (18%) of 28 patients had a PSA decline of â„50%. Three (25%) of 12 patients with measurable disease at baseline achieved an objective response. Of the five responders, two continue with PSA and radiographic response after 39.3 and 37.8 months. For the entire cohort, median follow-up was 37 months, and median PSA PFS time was 3.8 months (95%âCI: 2.8 to 9.9 months). Time to subsequent treatment was 7.21 months (95%âCI: 5.1 to 11.1 months). Median overall survival for all patients was 21.9 months (95%âCI: 14.7 to 28 .4 months), versus 41.7 months (95%âCI: 22.16 to not reached (NR)) in the responders. Of the three responders with baseline biopsies, one had MSI high disease with mutations consistent with DNA-repair defects. None had detectable PD-L1 expression.
CONCLUSIONS: Pembrolizumab has activity in mCRPC when added to enzalutamide. Responses were deep and durable and did not require tumor PD-L1 expression or DNA-repair defects.
TRIAL REGISTRATION NUMBER: clinicaltrials.gov (NCT02312557)
Whole blood fatty acid concentrations in the San CristĂłbal GalĂĄpagos tortoise (Chelonoidis chathamensis)
To continue releasing San CristĂłbal GalĂĄpagos tortoises housed in managed-care facilities at the Giant Tortoise Breeding Center of GalĂĄpagos National Park (Galapaguera de Cerro Colorado) to the Otoy Ecological Farm, health assessments and physical examinations were conducted. As a part of these wellness examinations, blood was drawn from 11 tortoises to analyze fatty acid concentrations. Fatty acid levels can provide insight into the nutritional profiles, immune status, and reproductive health of vertebrates. To the co-authorâs knowledge, there is no current information about fatty acids in this species. It was hypothesized that there would be inherent differences based on the different geographic ranges, diets, sex, and age of turtles. It was noted that the Ï-6/Ï-3 ratio was higher for the breeding center than for the ecological farm and that overall polyunsaturated fatty acids (PUFAs) did not have any significant differences. The Ï-6/Ï-3 findings can contribute to a global picture of these fatty acids across taxa, as reptiles are underrepresented in this area of research. Additional results are a resourceful starting point for future investigations into how fatty acids are affected in GalĂĄpagos tortoises
Endemic Human Monkeypox, Democratic Republic of Congo, 2001â2004
By analyzing vesicle fluids and crusted scabs from 136 persons with suspected monkeypox, we identified 51 cases of monkeypox by PCR, sequenced the hemagglutinin gene, and confirmed 94% of cases by virus culture. PCR demonstrated chickenpox in 61 patients. Coinfection with both viruses was found in 1 additional patient
Ankle Brachial Index and Subsequent Cardiovascular Disease Risk in Patients With Chronic Kidney Disease
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139089/1/jah31554.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139089/2/jah31554_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139089/3/jah31554-sup-0001-TableS1.pd
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