Identification of 6-Anilino Imidazo[4,5-]pyridin-2-ones as Selective DNA-Dependent Protein Kinase Inhibitors and Their Application as Radiosensitizers.

The dominant role of non-homologous end-joining in the repair of radiation-induced double-strand breaks identifies DNA-dependent protein kinase (DNA-PK) as an excellent target for the development of radiosensitizers. We report the discovery of a new class of imidazo[4,5-]pyridine-2-one DNA-PK inhibitors. Structure-activity studies culminated in the identification of as a nM DNA-PK inhibitor with excellent selectivity for DNA-PK compared to related phosphoinositide 3-kinase (PI3K) and PI3K-like kinase (PIKK) families and the broader kinome, and displayed DNA-PK-dependent radiosensitization of HAP1 cells.

W line shape in the resistively detected nuclear magnetic resonance.

The resistively detected nuclear magnetic resonance (RDNMR) performed on a two-dimensional electron gas is known to exhibit a peculiar 'dispersive' line shape at some filling factors, especially around ν = 1. Here, we study in detail the inversion of the dispersive line shape as a function of the filling factor from ν = 1 to 2/3. The RDNMR spectra show a new characteristic W line shape in the longitudinal resistance, whereas dispersive lines detected in the Hall resistance remain unchanged.

Spin injection in n-type resonant tunneling diodes.

We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have observed two emission lines attributed to neutral (X) and negatively charged excitons (X-). We have observed a voltage-controlled circular polarization degree from the quantum well emission for both lines, with values up to -88% at 15 T at low voltages which are ascribed to an efficient spin injection from the 2D gases formed at the accumulation layers.

Research midwives: look at the evidence!

Evidence based practice underpins modern healthcare and includes the use of research knowledge, consideration of an individual's circumstances and their personal preferences. Maternal and child health care interventions aim to prevent disease and disability and promote health and wellbeing. Before interventions are brought into practice the benefits and risks should be adequately evaluated to ensure clinicians and those receiving the interventions fully understand the potential effects.

Circular polarization in a non-magnetic resonant tunneling device.

We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T). The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW.

Measuring placental transfusion for term births: weighing babies with cord intact.

Objective: To estimate the volume and duration of placental transfusion at term.

Design: Prospective observational study.

Setting: Maternity unit in Bradford, UK.

Alternative positions for the baby at birth before clamping the umbilical cord.

Background: The third stage of labour is from birth of the baby until delivery of the placenta. Clamping the umbilical cord is one component of active management of the third stage. Deferring cord clamping allows blood flow between the baby and the placenta to continue; net transfer to the baby is called placental transfusion.

Care during the third stage of labour: a postal survey of UK midwives and obstetricians.

Background: There are two approaches to care during the third stage of labour: Active management includes three components: administration of a prophylactic uterotonic drug, cord clamping and controlled cord traction. For physiological care, intervention occurs only if there is clinical need. Evidence to guide care during the third stage is limited and there is variation in recommendations which may contribute to differences in practice.

Fock-Darwin-like quantum dot states formed by charged Mn interstitial ions.

We report a method of creating electrostatically induced quantum dots by thermal diffusion of interstitial Mn ions out of a p-type (GaMn)As layer into the vicinity of a GaAs quantum well. This approach creates deep, approximately circular, and strongly confined dotlike potential minima in a large (200 microm) mesa diode structure without need for advanced lithography or electrostatic gating. Magnetotunneling spectroscopy of an individual dot reveals the symmetry of its electronic eigenfunctions and a rich energy level spectrum of Fock-Darwin-like states with an orbital angular momentum component |lz| from 0 to 11.

Magnetic-field-induced suppression of electronic conduction in a superlattice.

We use a magnetic field applied along the axis of a semiconductor superlattice (SL) as a controllable means of creating a one-dimensional band structure. We demonstrate that the current flow through the SL is strongly suppressed when the electron motion perpendicular to the SL axis is strongly confined by the quantizing magnetic field. By modeling this behavior using semiclassical and nonequilibrium Green's function methods, we show that the observed quenching arises from a qualitative change in electron dynamics caused by increasing quantum confinement.

High temperature gate control of quantum well spin memory.

Time-resolved optical measurements in (110)-oriented GaAs/AlGaAs quantum wells show a tenfold increase of the spin-relaxation rate as a function of applied electric field from 20 to 80 kV cm(-1) at 170 K and indicate a similar variation at 300 K, in agreement with calculations based on the Rashba effect. Spin relaxation is almost field independent below 20 kV cm(-1) reflecting quantum well interface asymmetry. The results indicate the achievability of a voltage-gateable spin-memory time longer than 3 ns simultaneously with a high electron mobility.

Magnetotunneling spectroscopy of dilute Ga(AsN) quantum wells.

We use magnetotunneling spectroscopy to explore the admixing of the extended GaAs conduction band states with the localized N-impurity states in dilute GaAs(1-y)N(y) quantum wells. In our resonant tunneling diodes, electrons can tunnel into the N-induced E- and E+ subbands in a GaAs(1-y)N(y) quantum well layer, leading to resonant peaks in the current-voltage characteristics. By varying the magnetic field applied perpendicular to the current direction, we can tune an electron to tunnel into a given k state of the well; since the applied voltage tunes the energy, we can map out the form of the energy-momentum dispersion curves of E- and E+.

Tuneable optoelectronic bandpass filtering using a simple self-pulsating two-section laser.

We demonstrate tuneable optoelectronic bandpass filtering of an ASK modulated subcarrier data stream, using a two-section laser. Gain enhancement of 15dB is measured when the laser is locked to a 697MHz and 1100MHz carrier frequency.

Detrusor contraction strength in men undergoing prostatectomy.

Elective prostatectomy is a frequently performed operation but the outcome may not always be satisfactory. This is probably because a significant number of men, despite subjective symptoms, are not urodynamically obstructed before operation and the preoperative assessment of obstruction is not easy using conventional urodynamic criteria. We have calculated detrusor contraction strength (WF) in men before and after prostatectomy.