The confinement of laser interactions inside transparent materials assisted by tight optical focusing and short-pulsed nonlinear interactions has driven many high-resolution patterning and probing applications in science and technology. In thin transparent films, laser interactions confined to the film/substrate interface have underpinned blistering and ejection processes for nanofluidic channel fabrication, film patterning and cell catapulting. Here, we harness femtosecond lasers to drive nonlinear interactions within Fabry-Perot interference fringes to define narrow nanolength scale zones for highly resolved internal structuring of a film of refractive index, n film , at fringe maxima separated by l/2n film . This novel interaction internally cleaves the film to open subwavelength internal cavities and form thin membranes at single or multiple depths from which follow significant opportunities for writing multilevel nanofluidic channels inside the film, as well as ejecting nanodisks at quantized film depths for coloring and three-dimensional surface patterning that promise new compact types of lab-in-film devices.

Five hundred and sixty-three university students were interviewed to survey the practice of self-medication which was found to be very prevalent (94.0%). The most commonly used items included remedies for cough and cold, antipyretics and analgesics. Topical preparations and Chinese herbal medicines were also frequently consumed. Self-medication items were mostly obtained from home medicine cabinets and pharmacy shops (not necessarily staffed by registered pharmacists) and they also relied heavily on family members and previous illness experience for information on the medications they took. The healthcare professionals only played a minor role in the provision of drug information. Nevertheless, the concept of self-medication is well-established among these university students as they recognised that minor illness could be cared for without seeing a doctor. Healthcare professionals should assume more active roles in the provision of drug information and counselling so that a good self-care programme could be established.

1 To determine the toxic potentials of those Chinese pro prietary medicines (CPM) which are commonly used for self-poisoning by adults in Hong Kong, all patients admit ted to four of the eight general medical wards at the Prince of Wales Hospital between January 1988 and December 1993 were retrospectively studied. 2 There were 54 women and 17 men with their age rang ing from 15 to 86 years. Twenty-three subjects (32%) also took alcohol, chemicals or drugs. Of the 51 subjects (72%) who had taken topical medicaments, 22 had no symptoms while 28 had minor features of gastrointestinal irritation ( n = 26), mild ( n = 2) or severe ( n = 1) salicylate poisoning. Of the 17 subjects (24%) who had taken CPM tablets/cap sules, nine had mild symptoms including nausea/vomiting and drowsiness. The three remaining patients (4%) who had ingested liquid CPM preparations were asymptomatic. Elevated plasma salicylate or paracetamol concentrations (> 0.1 mmol l-1l) were found in some patients who had taken topical medicaments and CPM tablets/capsules, respectively. All the 71 patients completely recovered. 3 Most of the CPM used for self-poisoning in Hong Kong were of low to moderate toxicity except for those contain ing wintergreen oil (methyl salicylate).