Supramolecular Capsules Derived from Resorcin[4]arenes by H-Bonding and Metal Coordination: Synthesis,Characterization, and Single-Molecule Force Spectroscopy

Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitands to large supramolecular capsules is described. In addition, a new method of analyzing supramolecular recognition processes at the single molecule level is discussed. By measuring interaction forces in a hydrogen-bonded assembly using single-molecule force spectroscopy (SMFS), the dynamics of the self-assembly process can be evaluated. In the future, consequent application of this new technique will influence supramolecular design principles and the use of non-covalent interactions as construction elements in the field of nanotechnology.     

Can Worms Be Good?

Since 1999 programmers and security analysts all over the world have been engaged in a debate over the use of malicious techniques for “constructive” purposes. The use of viral techniques as a means of solving problems implies certain risks. Here are some examples.     

Modeling individual’s aging within a bacterial population using a pi-calculus paradigm

We propose an aging mechanism which develops in artificial bacterial populations fighting against antibiotic molecules. The mechanism is based on very elementary information gathered by each individual and elementary reactions as well. Though we do not interpret the aging process in strictly biological terms, it appears compliant with recent studies on the field, and physically feasible. The root of the aging mechanism is an adaptation strategy based on a thresholding operation that derives from theoretical results on stochastic monotone games. The methods for implementing it denote their rationale in that they represent a sophisticated dialect of pi-calculus, a widespread computational paradigm for implementing dynamics of massive populations with bipolar reactions. As a result we may implement processes that explain some typical patterns of the evolution of the immunosystems.     

A mobile microrobot actuated by a new electromagnetic wobblemicromotor

Microactuators are perhaps the most critical components of micromechatronic systems. Micromotors with diameters in the range between 10-1 mm are needed, but are not readily available for practical use. This paper describes a teleoperated mobile microrobot, actuated by a new electromagnetic wobble micromotor, and designed to participate in the “International Micro Robot Maze Contest" organized every year in Nagoya, Japan. This competition is an excellent benchmark to compare the performance of different microactuators. The working principle, design, fabrication, and performance of the wobble micromotor are described. The microrobot has a volume of 1 cm³ and incorporates two wobble micromotors, the rotors of which are the driving wheels. The micromotor generates a torque of 350 μN·m at each step and a maximum speed of about 180 r/min. The operator controls the motion of the microrobot by a remote joystick connected to the microrobot by flexible ultraminiature wires. The microrobot is highly maneuverable, has a maximum speed of 10 cm/s and can climb a slope of 15°. Two microrobots, which differ only in some constructive details, were fabricated. A smaller version (4-mm diameter) of the wobble micromotor has been developed for use in an innovative miniature robot system for diagnosis and intervention in the colon     

Intracranial meningioma and astrocytoma in the same patient. Case report and review of the literature

St. Jude Medical Center, a Sisters of St. Joseph Health System Corporation in Fullerton California, in their efforts at work redesign, realized that the success of a patient-centered care delivery system largely depended upon successful selection of the most suitable team members. The interviewing and selection process used at St. Jude Medical Center includes a structured interview process with integration of both situational and behavioral styles in conjunction with objective rating scales and values driven questions. A common thread woven into the hiring criteria for all levels of personnel in the patient-centered care delivery model was creativity, adaptability, interpersonal skills and compatibility of values. Additionally, the clinical competence of the caregiver within the scope of practice/responsibility was essential for their expanded role. Management and leadership abilities for the managers are also addressed in the interview and selection process to provide the best team members for the overall success of the patient-care redesign.     

Surface chemistry of SnO2 nanowires on Ag-catalyst-covered Si substrate studied using XPS and TDS methods

In this paper we investigate the surface chemistry, including surface contaminations, of SnO₂ nanowires deposited on Ag-covered Si substrate by vapor phase deposition (VPD), thanks to x-ray photoelectron spectroscopy (XPS) in combination with thermal desorption spectroscopy (TDS). Air-exposed SnO₂ nanowires are slightly non-stoichiometric, and a huge amount of C contaminations is observed at their surface. After the thermal physical desorption (TPD) process, SnO₂ nanowires become almost stoichiometric without any surface C contaminations. This is probably related to the fact that C contaminations, as well as residual gases from air, are weakly bounded to the crystalline SnO₂ nanowires and can be easily removed from their surface. The obtained results gave us insight on the interpretation of the aging effect of SnO₂ nanowires that is of great importance for their potential application in the development of novel chemical nanosensor devices.     

Combined Nano‐ and Micro‐Scale Topographic Cues for Engineered Vascular Constructs by Electrospinning and Imprinted Micro‐Patterns

The major cause of synthetic vessel failure is thrombus and neointima formation. To prevent these problems the creation of a continuous and elongated endothelium inside lumen vascular grafts might be a promising solution for tissue engineering. Different micro‐ and nano‐surface topographic cues including grooved micro‐patterns and electrospun fibers have been previously demonstrated to guide the uniform alignment of endothelial cells (ECs). Here, with a very simple and highly versatile approach we combined electrospinning with soft lithography to fabricate nanofibrous scaffolds with oriented fibers modulated by different micro‐grooved topographies. The effect of these scaffolds on the behavior of the ECs are analyzed, including their elongation, spreading, proliferation, and functioning using unpatterned random and aligned nanofibers (NFs) as controls. It is demonstrated that both aligned NFs and micro‐patterns effectively influence the cellular response, and that a proper combination of topographic parameters, exploiting the synergistic effects of micro‐scale and sub‐micrometer features, can promote EC elongation, allowing the creation of a confluent ECs monolayer in analogy with the natural endothelium as assessed by the positive expression of vinculin. Combining different micro‐ and nano‐topographic cues by complementary soft patterning and spinning technologies could open interesting perspectives for engineered vascular replacement constructions.