Protein assembly and DNA looping by the FokI restriction endonuclease

The FokI restriction endonuclease recognizes an asymmetric DNA sequence and cuts both strands at fixed positions upstream of the site. The sequence is contacted by a single monomer of the protein, but the monomer has only one catalytic centre and forms a dimer to cut both strands. FokI is also known to cleave DNA with two copies of its site more rapidly than DNA with one copy. To discover how FokI acts at a single site and how it acts at two sites, its reactions were examined on a series of plasmids with either one recognition site or with two sites separated by varied distances, sometimes in the presence of a DNA-binding defective mutant of FokI. These experiments showed that, to cleave DNA with one site, the monomer bound to that site associates via a weak protein–protein interaction with a second monomer that remains detached from the recognition sequence. Nevertheless, the second monomer catalyses phosphodiester bond hydrolysis at the same rate as the DNA-bound monomer. On DNA with two sites, two monomers of FokI interact strongly, as a result of being tethered to the same molecule of DNA, and sequester the intervening DNA in a loop

Decay Properties of 266^{266}Bh and 262^{262}Db Produced in the 248^{248}Cm + 23^{23}Na Reaction

Decay properties of an isotope $^{266}$Bh and its daughter nucleus $^{262}$Db produced by the $^{248}$Cm($^{23}$Na, 5\textit{n}) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. $^{266}$Bh was clearly identified from the correlation of the known nuclide, $^{262}$Db. The obtained decay properties of $^{266}$Bh and $^{262}$Db are consistent with those observed in the $^{278}$113 chain, which provided further confirmation of the discovery of $^{278}$113.Comment: Accepted for publication in J. Phys. Soc. JPN., to be published in Vol.78 No.

A simple, low-cost conductive composite material for 3D printing of electronic sensors

3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes

Improving access to care for people who inject drugs: qualitative evaluation of Project ITTREAT - an integrated community hepatitis C service

Achieving hepatitis C virus (HCV) elimination by 2030 requires an increased linkage to care for people who inject drugs (PWID). Project ITTREAT was established to mitigate barriers to HCV care by providing an integrated service within a local drug and alcohol treatment centre. This study aimed to explore the experiences of clients and staff involved in Project ITTREAT and assess the facilitators and barriers to a community‐based HCV service. Between October 2014 and April 2016, drug and alcohol treatment attendees were interviewed using one‐to‐one semi‐structured interviews. Drug and alcohol treatment staff took part in focus groups. All data were recorded, transcribed verbatim and analysed using thematic content analysis. Fifteen drug and alcohol treatment attendees with current/previous HCV infection were interviewed, and 15 staff members contributed across two focus groups. Drug and alcohol treatment staff and attendees reported that Project ITTREAT facilitated access to HCV care by mitigating previous negative hospital‐based experiences. Other key facilitators were positive narratives around HCV care, and drug and alcohol treatment attendees being well engaged in their drug/alcohol recovery. Barriers included a lack of stability in drug and alcohol treatment attendees, negative discourse around testing/treatment and stigma associated with attending the drug and alcohol treatment to access HCV treatment in some who had successfully achieved drug rehabilitation. Our findings indicate the positive impact of an integrated and personalized community‐based service delivered by a dedicated hepatitis nurse. This played a crucial role in reducing barriers to HCV care for PWID. Our work also highlights areas for future investment including non–DAT‐based community services and increasing awareness of new treatments amongst this cohort

Asymptotic Expansions for Stationary Distributions of Perturbed Semi-Markov Processes

New algorithms for computing of asymptotic expansions for stationary distributions of nonlinearly perturbed semi-Markov processes are presented. The algorithms are based on special techniques of sequential phase space reduction, which can be applied to processes with asymptotically coupled and uncoupled finite phase spaces.Comment: 83 page