Fiber-integrated 780 nm source for visible parametric generation.

We report the development of a fully fiber-integrated pulsed master oscillator power fibre amplifier (MOPFA) source at 780 nm, producing 3.5 W of average power with 410 ps pulses at a repetition rate of 50 MHz. The source consists of an intensity modulated 1560 nm laser diode amplified in an erbium fiber amplifier chain, followed by a fiber coupled periodically poled lithium niobate crystal module for frequency doubling. The source is then used for generating visible light through four-wave mixing in a length of highly nonlinear photonic crystal fiber: 105 mW at 668 nm and 95 mW at 662 nm are obtained, with pump to anti-Stokes conversion slope efficiencies exceeding 6% in both cases.

Cough mixture misuse in Hong Kong--an emerging psychiatric problem?

Cough mixture misuse has become a focus of concern in Hong Kong since the late 1980s. Psychiatric admissions related to cough mixture misuse have been reported with increasing frequency during the past 5 years. A retrospective chart review of psychiatric admissions related to cough mixture misuse for a 54-month period was conducted in two psychiatric units in Hong Kong. Twenty-seven subjects were identified. The main psychiatric presentations included acute organic brain syndrome, schizophreniform psychosis and affective episode. They appeared to be associated with the pharmacological activities of opiates, antihistamines and sympathomimetics, the main ingredients of most cough mixtures.

Idiopathic calcification of the basal ganglia.

Idiopathic calcification of the basal ganglia is a rare disorder characterized by neuropsychiatric abnormalities, a movement disturbance of parkinsonian and/or choreoathetoid type and dense calcification of the basal ganglia. We report a 60 year old patient diagnosed as having delusional disorder and tardive dyskinesia who was subsequently found to be suffering from idiopathic calcification of the basal ganglia.

Clinical and polygraphic characteristics of patients with respiratory dyskinesia.

Respiratory dyskinesia is characterized by irregularity in rate, rhythm and depth of breathing. This study reports on the clinical features of 11 patients with respiratory dyskinesia identified from a mental hospital in Hong Kong, together with the results of the 24-hour polygraphic recording of seven patients. Virtually all patients with respiratory dyskinesia had tardive dyskinesia. However, the condition was missed or misdiagnosed in all cases by the case psychiatrists. The respiratory irregularity persisted for most of the day and only disappeared when patients took a prolonged rest or fell asleep. A standardised clinical examination for respiratory dyskinesia is proposed.