644 research outputs found

    Dominant Design or Multiple Designs: The Flash Memory Card Case

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    Literature suggests that in battles between competing designs, ultimately one design will emerge as dominant to the detriment of the others. Various factors and forces have been identified to explain this phenomenon. Yet, sometimes no dominant design emerges at all and multiple competing designs coexist in the market.. The Flash Memory Card Industry provides an example of this. In this study, we use this example as a case to investigate the circumstances under which an industry has a tendency toward multiple designs. The case shows that a combination of factors may result in multiple designs and we argue that such a combination of factors will increasingly also apply in other cases

    Homocysteine levels and treatment effect in the prospective study of pravastatin in the elderly at risk

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    Objectives: To assess the effect of preventive pravastatin treatment on coronary heart disease (CHD) morbidity and mortality in older persons at risk for cardiovascular disease (CVD), stratified according to plasma levels of homocysteine.<p></p> Design: A post hoc subanalysis in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), started in 1997, which is a double-blind, randomized, placebo-controlled trial with a mean follow-up of 3.2 years.<p></p> Setting: Primary care setting in two of the three PROSPER study sites (Netherlands and Scotland).<p></p> Participants: Individuals (n = 3,522, aged 70–82, 1,765 male) with a history of or risk factors for CVD were ranked in three groups depending on baseline homocysteine level, sex, and study site.<p></p> Intervention: Pravastatin (40 mg) versus placebo.<p></p> Measurements: Fatal and nonfatal CHD and mortality.<p></p> Results: In the placebo group, participants with a high homocysteine level (n = 588) had a 1.8 higher risk (95% confidence interval (CI) = 1.2–2.5, P = .001) of fatal and nonfatal CHD than those with a low homocysteine level (n = 597). The absolute risk reduction in fatal and nonfatal CHD with pravastatin treatment was 1.6% (95% CI = −1.6 to 4.7%) in the low homocysteine group and 6.7% (95% CI = 2.7–10.7%) in the high homocysteine group (difference 5.2%, 95% CI = 0.11–10.3, P = .046). Therefore, the number needed to treat (NNT) with pravastatin for 3.2 years for benefit related to fatal and nonfatal CHD events was 14.8 (95% CI = 9.3–36.6) for high homocysteine and 64.5 (95% CI = 21.4–∞) for low homocysteine.<p></p> Conclusion: In older persons at risk of CVD, those with high homocysteine are at highest risk for fatal and nonfatal CHD. With pravastatin treatment, this group has the highest absolute risk reduction and the lowest NNT to prevent fatal and nonfatal CHD.<p></p&gt

    Spreading Dynamics of Polymer Nanodroplets

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    The spreading of polymer droplets is studied using molecular dynamics simulations. To study the dynamics of both the precursor foot and the bulk droplet, large drops of ~200,000 monomers are simulated using a bead-spring model for polymers of chain length 10, 20, and 40 monomers per chain. We compare spreading on flat and atomistic surfaces, chain length effects, and different applications of the Langevin and dissipative particle dynamics thermostats. We find diffusive behavior for the precursor foot and good agreement with the molecular kinetic model of droplet spreading using both flat and atomistic surfaces. Despite the large system size and long simulation time relative to previous simulations, we find no evidence of hydrodynamic behavior in the spreading droplet.Comment: Physical Review E 11 pages 10 figure

    3D-microfibers improve the shear modulus of hydrogel composites

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    A major challenge in the field of biofabrication is to manufacture a construct soft enough to elicit optimal cell behavior while possessing the mechanical properties required to withstand the complex in-vivo mechanical environment [1]. Hydrogels that were reinforced with polycaprolactone (PCL) fibers arranged in box structures, obtained by melt electrospinning writing (MEW), showed a synergistic increase in the compressive Young’s modulus [2], however, collapsed in-vivo, possibly due to shear stress. Here, we used MEW to produce specifically designed PCL fibers to stabilize an existing structure and subsequently improve the shear modulus of hydrogel-fiber composites. Instrument parameters affecting fabrication of these fibers were studied and stabilizing fibers used for shear testing (fiber diameter = 13.16 ± 0.11 μm) were made with an amplitude of 500 μm, wavelength of 400 μm, and collector velocity of 400 mm/min, at a height of 20 layers (330 m) (Figure 1A). The stabilizing fibers were embedded in 5, 10, and 15 wt.% polyacrylamide and a frequency sweep test (0.05 – 500 rad/s, 0.01% strain, n = 5) was performed to measure the complex shear modulus of the hydrogel-fiber composites. To correspond the direction of the stabilizing fibers with the torque of the rheometer, stabilizing fibers were printed in a specific architecture (Figure 1B). Stabilizing fibers increased the complex shear modulus by 148%, 127%, and 165%, when embedded within a 5%, 10%, and 15% polyacrylamide hydrogel, respectively (Figure 1C). This study highlights the capacity of MEW to increase shear properties of matrix-fiber composites through inclusion of stabilizing fibers. Please click Additional Files below to see the full abstract

    Molecular imaging biomarkers for immune checkpoint inhibitor therapy

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    Immune checkpoint inhibitors (ICIs) have substantially changed the field of oncology over the past few years. ICIs offer an alternative treatment strategy by exploiting the patients’ immune system, resulting in a T cell mediated anti-tumor response. These therapies are effective in multiple different tumor types. Unfortunately, a substantial group of patients do not respond to ICIs. Molecular imaging, using single-photon emission computed tomography (SPECT) and positron emission tomography (PET), can provide non-invasive whole-body visualization of tumor and immune cell characteristics and might support patient selection or response evaluations for ICI therapies. In this review, recent studies with 18F-fluorodeoxyglucose-PET imaging, imaging of immune checkpoints and imaging of immune cells will be discussed. These studies are until now mainly exploratory, but the first results suggest that molecular imaging biomarkers could have a role in the evaluation of ICI therapy

    First-in-human study of the biodistribution and pharmacokinetics of <sup>89</sup>Zr-CX-072, a novel immunopet tracer based on an anti–PD-L1 probody

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    Purpose: CX-072, a PD-L1–targeting Probody therapeutic, is engineered to be activated by tumor proteases that remove a masking peptide. To study effects on biodistribution and pharmacokinetics, we performed 89Zr-CX-072 positron emission tomography (PET) imaging. Experimental Design: Patients received 1 mg, 37 MBq 89Zr-CX-072 plus 0, 4, or 9 mg unlabeled CX-072 and PET scans at days 2, 4, and 7. After that, treatment comprised 10 mg/kg CX-072 q2 weeks (n ¼ 7) þ 3 mg/kg ipilimumab q3w 4 (n ¼ 1). Normal organ tracer uptake was expressed as standardized uptake value (SUV)mean and tumor uptake as SUVmax. PD-L1 expression was measured immunohistochemically in archival tumor tissue. Results: Three of the eight patients included received 10-mg protein dose resulting in a blood pool mean SUVmean SD of 4.27 0.45 on day 4, indicating sufficient available tracer. Tumor uptake was highest at day 7, with a geometric mean SUVmax 5.89 (n ¼ 113) and present in all patients. The median follow-up was 12 weeks (4–76þ). One patient experienced stable disease and two patients a partial response. PD-L1 tumor expression was 90% in one patient and ≤1% in the other patients. Mean SUVmean SD day 4 at 10 mg in the spleen was 8.56 1.04, bone marrow 2.21 0.46, and liver 4.97 0.97. Four patients out of seven showed uptake in normal lymph nodes and Waldeyer’s ring. The tracer was intact in the serum or plasma. Conclusions: 89Zr-CX-072 showed tumor uptake, even in lesions with ≤1% PD-L1 expression, and modest uptake in normal lymphoid organs, with no unexpected uptake in other healthy tissues

    Health-Related Quality of Life and Mortality in a General and Elderly Population of Patients With Type 2 Diabetes (ZODIAC-18)

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    OBJECTIVE- Diabetes negatively impacts the health-related quality of life (HRQOL) of patients with type 2 diabetes. An earlier analysis showed HRQOL to be associated with mortality, which suggests that measuring HRQOL could have clinical implications. We studied the association between HRQOL and total and cardiovascular mortality in patients with type 2 diabetes during long-term follow-up and specifically focused on old age and sex differences. RESEARCH DESIGN AND METHODS- HRQOL was measured in a prospectively followed cohort of 1,353 patients with type 2 diabetes using the RAND-36. Cox proportional hazard models were used to measure the independent effect of baseline HRQOL on mortality. RESULTS- During a mean follow-up of 9.6 years, 570 (42%) patients died, 280 of whom died of cardiovascular disease (49%). The Physical Component Score (PCS) and the Mental Component Score (MCS) were inversely associated with total mortality, with hazard ratios of 0.988(95% CI 0.983-0.993) and 0.990(95% CI 0.985-0.995), respectively. A 10-point-higher score on the PCS and MCS decreased the risk for total mortality by 11 and 10%, respectively. An inverse relationship with mortality was also seen for men, women, and for patients aged >75 years. Mental health was significantly related to mortality in men but not in women. CONCLUSIONS- Lower physical and mental HRQOL was associated with a higher total mortality and cardiovascular mortality in patients with type 2 diabetes; this is also the case when studying men and women and the elderly separately. The dimension mental health, related to depression and anxiety, was only associated with mortality in men, not in women

    A broader role for AmyR in Aspergillus niger: regulation of the utilisation of d-glucose or d-galactose containing oligo- and polysaccharides

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    AmyR is commonly considered a regulator of starch degradation whose activity is induced by the presence of maltose, the disaccharide building block of starch. In this study, we demonstrate that the role of AmyR extends beyond starch degradation. Enzyme activity assays, genes expression analysis and growth profiling on d-glucose- and d-galactose-containing oligo- and polysaccharides showed that AmyR regulates the expression of some of the Aspergillus niger genes encoding α- and β-glucosidases, α- and β- galactosidases, as well as genes encoding α-amlyases and glucoamylases. In addition, we provide evidence that d-glucose or a metabolic product thereof may be the inducer of the AmyR system in A. niger and not maltose, as is commonly assumed
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