Sterically stabilized lock and key colloids: A self-consistent field theory study

A self-consistent field theory study of lock and key type interactions between sterically stabilized colloids in polymer solution is performed. Both the key particle and the lock cavity are assumed to have cylindrical shape, and their surfaces are uniformly grafted with polymer chains. The lock-key potential of mean force is computed for various model parameters, such as length of free and grafted chains, lock and key size matching, free chain volume fraction, grafting density, and various enthalpic interactions present in the system. The lock-key interaction is found to be highly tunable, which is important in the rapidly developing field of particle self-assembly

Use of the KlADH4 promoter for ethanol-dependent production of recombinant human serum albumine in Kluyveromyces lactis

KlADH4 is a gene of Kluyveromyces lactis encoding a mitochondrial alcohol dehydrogenase activity which is specifically induced by ethanol. The promoter of this gene was used for the expression of heterologous proteins in K. lactis, a very promising organism which can be used as an alternative host to Saccharomyces cerevisiae due to its good secretory properties. In this paper we report the ethanol-driven expression in K. lactis of the bacterial beta-glucuronidase and of the human serum albumin (HSA) genes under the control of the KlADH4 promoter. In particular, we studied the extracellular production of recombinant HSA (rHSA) with integrative and replicative vectors and obtained a significant increase in the amount of the protein with multicopy vectors, showing that no limitation of KlADH4 trans-acting factors occurred in the cells. By deletion analysis of the promoter, we identified an element (UASE) which is sufficient for the induction of KlADH4 by ethanol and, when inserted in the respective promoters, allows ethanol-dependent activation of other yeast genes, such as PGK and LAC4. We also analyzed the effect of medium composition on cell growth and protein secretion. A clear improvement in the production of the recombinant protein was achieved by shifting from batch cultures (0.3 g/liter) to fed-batch cultures (1 g/liter) with ethanol as the preferred carbon source

When Geometry is not Enough: Using Reflector Markers in Lidar SLAM

Lidar-based SLAM systems perform well in a wide range of circumstances by relying on the geometry of the environment. However, even mature and reliable approaches struggle when the environment contains structureless areas such as long hallways. To allow the use of lidar-based SLAM in such environments, we propose to add reflector markers in specific locations that would otherwise be difficult. We present an algorithm to reliably detect these markers and two approaches to fuse the detected markers with geometry-based scan matching. The performance of the proposed methods is demonstrated on real-world datasets from several industrial environments.Comment: Accepted at IROS 202

Polymer Brushes in Cylindrical Pores: Simulation versus Scaling Theory

The structure of flexible polymers endgrafted in cylindrical pores of diameter D is studied as a function of chain length N and grafting density \sigma, assuming good solvent conditions. A phenomenological scaling theory, describing the variation of the linear dimensions of the chains with \sigma, is developed and tested by Molecular Dynamics simulations of a bead-spring model.Comment: 35 pages, 38 figure

Why Do Adult Patients With Cancer Not Seek Help for Their Depressive Symptoms?:The Role of Illness Perceptions, Coping, and Social Support

Background: Up to 75% of cancer patients with depressive symptoms do not make use of psychological care.Objective: To examine how perceptions of and coping with depressive symptoms and perceived social support in adults with cancer are associated with their need for psychological care, concurrently and over time.Methods: In this longitudinal study, 127 participants who received a cancer diagnosis in the past 5 years, experienced at least moderate depressive symptoms, and were not receiving psychological help, completed 2 self-report questionnaires (3 months apart) including the brief Illness Perception Questionnaire and brief Coping Orientation to Problems Experienced Inventory and Social Support List.Results: Participants with stronger belief in the efficacy of psychological care and more likely to use avoidant coping reported a greater need for psychological care at both data points. Social support was not significantly associated with perceived need for psychological care.Conclusions: Stronger perceived treatment control and greater use of avoidant coping were significantly associated with a greater perceived need for psychological care.Implications for practice: People with cancer may benefit from being informed about the efficacy of depression treatment. Furthermore, health care professionals should be aware that avoidant coping may complicate psychological care seeking for a group of adults with cancer experiencing depressive symptoms and having a need for psychological care.Foundational: Illness perceptions and coping mechanisms can predict cancer patients’ need for psychological care. Providing information about treatment options and its efficacy, together with targeting avoidant coping may increase adequate decision-making and possibly the uptake of psychological care

Identifying Patients with COPD in Need for Psychosocial Care Through Screening with the HSCL-25 and the CCQ Mental State

High levels of psychological distress are documented in patients with COPD. This study investigates the extent to which patients with a high score on the Hopkins Symptoms Checklist-25 (HSCL-25) or with a high score on the Mental State scale of the Clinical COPD Questionnaire (CCQ) endorse a need for psychosocial care, and investigates several characteristics of patients with a need. Outpatients with COPD of the Department of Pulmonary Diseases of a University Medical Center were assessed with the HSCL-25, CCQ and a question on need for psychosocial care. For patients indicating a need, the percentage of patients with HSCL-25 ≥39 was compared with the percentage of patients with CCQ Mental State >2 and tested with a Chi-square. In total 323 patients participated; 57% of them were distressed according to the HSCL-25 (≥39) and 20% according to the CCQ Mental State (>2); 28% reported a need for psychosocial care. For patients reporting a need for psychosocial care a higher percentage was identified by the HSCL-25 than by the CCQ Mental State (χ2 = 9.41, p <. 002) and they were younger than patients without a need (t = 4.48, p <. 001). No differences existed for sex, FEV1, FEV1% predicted or medical comorbidities. The HSCL-25 identified more patients in need than the CCQ Mental State scale. However, not all patients with a need were identified. No relationship was found between need for psychosocial care and illness variables or comorbidities. Distress screening is questioned as the most effective way to identity patients with COPD in need for psychosocial care

Single polymer adsorption in shear: flattening versus hydrodynamic lift and corrugation effects

The adsorption of a single polymer to a flat surface in shear is investigated using Brownian hydrodynamics simulations and scaling arguments. Competing effects are disentangled: in the absence of hydrodynamic interactions, shear drag flattens the chain and thus enhances adsorption. Hydrodynamic lift on the other hand gives rise to long-ranged repulsion from the surface which preempts the surface-adsorbed state via a discontinuous desorption transition, in agreement with theoretical arguments. Chain flattening is dominated by hydrodynamic lift, so overall, shear flow weakens the adsorption of flexible polymers. Surface friction due to small-wavelength surface potential corrugations is argued to weaken the surface attraction as well.Comment: 6 pages, 4 figure

Influence of solvent quality on polymer solutions: a Monte Carlo study of bulk and interfacial properties

The effect of solvent quality on dilute and semi-dilute regimes of polymers in solution is studied by means of Monte Carlo simulations. The equation of state, adsorptions near a hard wall, wall-polymer surface tension and effective depletion potentials are all calculated as a function of concentration and solvent quality. We find important differences between polymers in good and theta solvents. In the dilute regime, the physical properties for polymers in a theta solvent closely resemble those of ideal polymers. In the semi-dilute regime, however, significant differences are found.Comment: 10 pages, 13 figure