Effective algorithm to encrypt information based on self-assembly of DNA tiles.

We present an error-tolerance scheme to encrypt information in DNA structures based on a one-time-pad (OTP) cryptosystem that provides theoretically unbreakable security. The problem of the DNA-based OTP encryption is the loss of synchronization between the message and the encryption key due to the DNA property of accepting mismatched base pairs. We propose a new implementation idea of encrypting algorithm with the fourfold fault tolerance against mismatches than the ordinary DNA XOR operation. Although there are several problems to be solved toward the practical use at this moment, it is expected that the molecular computation using DNA tiles will enlarge the application possibility of the OTP cryptosystem.

Programmed regulation of conformational switching in diagnostic biomolecular automata using error control molecules.

We aim to present novel biomolecular automata for transcriptome diagnosis. We already proposed several biomolecular probes for the prediction of oral squamous cell carcinoma as a model case and evaluated the system noise and sensitivity. Here we introduce an error control element and discuss the specificity of the system.

Malachite green-conjugated microtubules as mobile bioprobes selective for malachite green aptamers with capturing/releasing ability.

We have developed a novel mobile bioprobe using a conjugate of a kinesin-driven microtubule (MT) and malachite green (MG) as a platform for capturing MG RNA aptamers. The fluorescence of MG increases when it is bound to an MG aptamer, allowing MT-MG conjugates to work as sensors of RNA transcripts containing the MG aptamer sequence. Kinesin motor proteins provide an effective driving force to create mobile bioprobes without any manipulation. Although the fluorescence of a small number of MG-binding aptamers is low, the self-organization of tubulins into MTs enables the microscopic observation of the bound aptamers by collecting them on MTs. We demonstrate that MT-MG conjugates can select target aptamers from a transcription mixture and transport them without losing their inherent motility. Because the MG aptamer binds MG in a reversible manner, MT-MG conjugates can conditionally load and unload the target aptamers. This is one advantage of this system over the molecular probes developed previously in which reversible unloading is impossible due to high-affinity binding, such as between avidin and biotin. Furthermore, an MT-MG conjugate can be used as a platform for other MG aptameric sensors with recognition regions for various target analytes optimized by further selection procedures. This is the first step to applying living systems to in vitro devices. This technique could provide a new paradigm of mobile bioprobes establishing high-throughput in vitro selection systems using microfluidic devices operating in parallel.

A case of canine gastrinoma.

The dog of this case was a 10-year-old Shih Tzu with refractory vomiting, diarrhea and anorexia. Endoscopy revealed an unclear at gastric angle, a stenosis at pyloric antrum and congestion in duodenal mucosa. Since abnormal shadows of irregular echo-levels were disclosed by pancreas ultrasonography, serum gastrin level was determined with a suspect of gastrinoma. And an increase of serum gastrin was demonstrated. In addition, postmortem histological examination revealed that the pancreatic cells were positive for gastrin. Based on these findings, the dog was diagnosed as pancreatic gastrinoma.

Characterization of flow reduction properties in an aneurysm due to a stent.

We consider a lattice Boltzmann simulation of blood flow in a vessel deformed by the presence of an aneurysm. Modern clinical treatments involve introducing a stent (a tubular mesh of wires) into the cerebral artery in order to reduce the flow inside the aneurysm and favor its spontaneous reabsorption. A crucial question is to design the stent with suitable porosity so as to produce the most effective flow reduction. We propose a stent positioning factor as a characterizing tool for stent pore design in order to describe the flow reduction effect and reveal the several flow reduction mechanisms using this effect.