Efficiency analysis of surgical services by combined use of data envelopment analysis and gray relational analysis.

The aim of this study was to determine the efficiency of surgical services offered by a public hospital, to rank efficient services and to determine important factors on efficiency of services. DEA (to determine efficiency of services) and GRA (to rank efficient services and ranking of important variables in efficiency) were used in this study. DEA showed that all services were observably efficient except Cardiovascular and Plastic surgery. GRA showed that the services of Ophthalmology, Otorhinolaryngology (ENT) and Paediatric Surgery shared the first three ranks in order of decreasing frequency. Findings obtained from GRA, the most important variables in the performances of surgical services were found to be the number of patients and healthcare personnel. Findings obtained from this study are thought to help inefficient services to attain an efficient structure. When the importance of this issue regarding hospitals and the government is considered, similarly designed studies should be continually updated and revised in line with changing circumstances. When shortcomings in the existing literature are taken into account, this could be considered to be a pioneer study that will contribute to the literature and promote future studies to be conducted on this issue.

Growing Directed Acyclic Graphs: Optimization Functions for Pathway Reconstruction Algorithms.

A major challenge in molecular systems biology is to understand how proteins work to transmit external signals to changes in gene expression. Computationally reconstructing these signaling pathways from protein interaction networks can help understand what is missing from existing pathway databases. We formulate a new pathway reconstruction problem, one that iteratively grows directed acyclic graphs (DAGs) from a set of starting proteins in a protein interaction network. We present an algorithm that provably returns the optimal DAGs for two different cost functions and evaluate the pathway reconstructions when applied to six diverse signaling pathways from the NetPath database. The optimal DAGs outperform an existing k-shortest paths method for pathway reconstruction, and the new reconstructions are enriched for different biological processes. Growing DAGs is a promising step toward reconstructing pathways that provably optimize a specific cost function.

Micro-UFO (Untethered Floating Object): A Highly Accurate Microrobot Manipulation Technique.

A new microrobot manipulation technique with high precision (nano level) positional accuracy to move in a liquid environment with diamagnetic levitation is presented. Untethered manipulation of microrobots by means of externally applied magnetic forces has been emerging as a promising field of research, particularly due to its potential for medical and biological applications. The purpose of the presented method is to eliminate friction force between the surface of the substrate and microrobot. In an effort to achieve high accuracy motion, required magnetic force for the levitation of the microrobot was determined by finite element method (FEM) simulations in COMSOL (version 5.3, COMSOL Inc., Stockholm, Sweden) and verified by experimental results. According to position of the lifter magnet, the levitation height of the microrobot in the liquid was found analytically, and compared with the experimental results head-to-head. The stable working range of the microrobot is between 30 µm to 330 µm, and it was confirmed in both simulations and experimental results. It can follow the given trajectory with high accuracy (<1 µm error avg.) at varied speeds and levitation heights. Due to the nano-level positioning accuracy, desired locomotion can be achieved in pre-specified trajectories (sinusoidal or circular). During its locomotion, phase difference between lifter magnet and carrier magnet has been observed, and relation with drag force effect has been discussed. Without using strong electromagnets or bulky permanent magnets, our manipulation approach can move the microrobot in three dimensions in a liquid environment.