Gravity-oriented microfluidic device for uniform and massive cell spheroid formation

We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours.     

Distributed fusion receding horizon filtering for uncertain linear stochastic systems with time-delay sensors

A new distributed fusion receding horizon filtering problem is investigated for uncertain linear stochastic systems with time-delay sensors. First, we construct a local receding horizon Kalman filter having time delays (LRHKFTDs) in both the system and measurement models. The key technique is the derivation of recursive error cross-covariance equations between LRHKFTDs in order to compute the optimal matrix fusion weights. It is the first time to present distributed fusion receding horizon filter for linear discrete-time systems with delayed sensors. It has a parallel structure that enables processing of multisensory time-delay measurements, so the calculation burden can be reduced and it is more reliable than the centralized version if some sensors turn faulty. Simulations for a multiple time-delays system show the effectiveness of the proposed filter in comparison with centralized receding horizon filter and non-receding versions.     

Congenital atresia of the left main coronary artery in an infant

Congenital atresia of the left main coronary artery is a rare occurrence, and surgical revascularizationbypass graft is required. We here report a rare case of congenital coronary anomaly in an infant. A 10-month-old male infant was admitted to the hospital with heart failure symptoms. Echocardiographic examinations revealed mitral valve regurgitation and ischemic changes of the anterolateral papillary muscle and chordae. Coronary angiography showed atresia of the left main coronary artery with a severe hypoplastic left anterior descending artery and a circumflex coronary artery. Unfortunately, sudden cardiac arrest occurred after catheterization and the infant did not recover despite of immediate cardiopulmonary resuscitation. Further studies are needed to find a newer diagnostic method to detect coronary anomaly in an infant, and coronary angiography, if necessary, has to be performed very carefully.     

Mentoring in the virtual organization: keys to building successful schools and businesses

Mentoring can take on a whole new perspective when people have a common goal but are in different physical locations. The benefits of virtual mentoring, in other words, mentoring when the mentor and mentee are not geographically co‐located, and which occurs mainly by electronic communication, can be substantial. They include lowered costs, increased access to mentors, and no limitations on space, time, and location. There are also disadvantages to virtual mentoring. Notable among these is the lack of face‐to‐face communication, something that adds another dimension to understanding the tone and attitude of messages between mentors and mentees. This article not only defines and analyzes the concept of mentoring as performed in the virtual organization but also deals with phases of mentoring and types of mentors used in this relatively new work environment. The synthesis of the literature and the authors’ experience results in a list of keys to successful mentoring in the virtual organization. These are: trust, self‐motivation, flexibility, communication skills, and technological skills. In addition, implications for worldwide mentoring are discussed.