Mask-less ultraviolet photolithography based on CMOS-driven micro-pixel light emitting diodes.

We report on an approach to ultraviolet (UV) photolithography and direct writing where both the exposure pattern and dose are determined by a complementary metal oxide semiconductor (CMOS) controlled micro-pixellated light emitting diode array. The 370 nm UV light from a demonstrator 8 x 8 gallium nitride micro-pixel LED is projected onto photoresist covered substrates using two back-to-back microscope objectives, allowing controlled demagnification. In the present setup, the system is capable of delivering up to 8.8 W/cm2 per imaged pixel in circular spots of diameter approximately 8 microm. We show example structures written in positive as well as in negative photoresist.

An implementation of a spike-response model with escape noise using an avalanche diode.

This paper introduces a novel probabilistic spike-response model through the combination of avalanche diode-generated Poisson distributed noise, and a standard exponential decay-based spike-response curve. The noise source, which is derived from a 0.35-µm single-photon avalanche diode (kept in the dark), was tested experimentally to verify its characteristics, before being combined with a field-programmable gate-array implementation of a spike-response model. This simple model was then analyzed, and shown to reproduce seven of eight behaviors recorded during an extensive study of the ventral medial hypothalamic (VMH) region of the brain. It is thought that many of the cell types found within the VMH are fed from a tonic noise synaptic input, where the patterns generated are a product of their spike response and not their interconnection. This paper shows how this tonic noise source can be modelled, and due to the independent nature of the noise sources, provides an avenue for the exploration of networks of noise-fueled neurons, which play a significant role in pattern generation within the brain.

Alfentanil for short duration laparoscopic procedures.

Alfentanil in low dosage (8 micrograms kg-1) as an analgesic agent for short duration surgery was evaluated. Forty-one women undergoing laparoscopy received double-blind either alfentanil 8 micrograms kg-1 or normal saline at induction, and all received thiopentone, alcuronium, enflurane, nitrous oxide and oxygen. The fall in mean arterial pressure (MAP) with induction was similar between groups. The MAP following intubation with alfentanil was unchanged, while with normal saline a mean rise of 23 (SD 15.2) mmHg occurred (P less than 0.001). The pulse rate following intubation showed a smaller rise (P less than 0.001) with alfentanil of 26 (SD 14.6) beats min-1, than the normal saline group of 46 (SD 13.3) beats min-1. Alfentanil was found to be a safe and effective analgesic agent in short duration surgery, by reducing sympathetic responses to intubation without cardiovascular depression or compromise of postoperative recovery.