Subdiffraction-limited focusing lens

We describe techniques for making a diffractive optical element that produces a subdiffraction-limited spot size. We provide experimental verification, using a diffraction optical element that is constructed on a magneto-optic spatial light modulator.

Random mask encoding of multiplexed phase-only and binary phase-only filters

In the formation of multiplexed filters, the phase-only and binary phase-only operations result in spurious cross terms and a nonlinear scaling. We use complementary random binary patterns having different pattern densities to encode the various functions within the multiplexed function. The orthogonality of these complementary masks permits separability of the phase-only or binary phase-only operations. By changing the pixel density of the random pattern, we can easily change the relative weights of the functions that compose the multiplexed filter. Experimental results are shown that demonstrate the effectiveness of this approach.

Faecal enzymes: in vivo human skin irritation

Digestive enzymes in faeces have been reported to possess skin irritation potential. The present study was designed to investigate the in vivo irritant potentials of faecal concentrations of proteolytic and lipolytic digestive enzymes in bile salt mixtures. In a 21-day cumulative irritation assay, clinical evaluation and noninvasive bioengineering techniques were used. 5 days occlusive exposure to phosphate buffer (pH = 8) caused no visual skin damage but reflectance spectroscopy demonstrated significant vasodilation (p < 0.01) and increases in transepidermal water loss (TEWL) and skin pH were also observed (p < 0.01). These increases were still present at days 12 and 19. Occlusive exposure to physiologic concentrations of faecal enzymes resulted in significant visual and objective scores at day 5, 12, and 19, with increased readings as a function of exposure time (p < 0.01). The enzyme mixture containing lipase caused delayed onset of skin erythema and epidermal barrier disruption compared to elastase and chymotrypsin containing solutions. Prolonged occlusive exposure to digestive enzymes in faecal concentrations caused severe skin erythema and epidermal barrier disruption in a human model, suggesting a possible etiologic role of digestive enzymes in perianal, circumstomal or diaper dermatitis.

Teaching venipuncture in an outpatient surgery unit

In the spring of 1992, the skill of venipuncture, inserting an intravenous (IV) needle, was added to the last quarter in an associate degree nursing curriculum. After theory and demonstration, 71 graduating students were rotated through an 8-hour venipuncture practice laboratory in an outpatient surgery unit. The instructor worked with a single student to start an IV line on a client. The personalized instructional method and sequencing of events resulted in a positive learning experience.

Prognosis in cystic fibrosis treated with continuous flucloxacillin from the neonatal period

All newborn infants in East Anglia are screened for cystic fibrosis by blood immunoreactive trypsin assay at 7 days. Thirty eight infants with cystic fibrosis were randomised to treatment with either continuous oral flucloxacillin 250 mg/day (group P, n = 18) or with episodic antimicrobials as clinically indicated (group E, n = 20). Their progress was monitored from diagnosis to 24 months by a nurse coordinator who visited all infants regularly, at home and in hospital, to collect anthropometric, dietary, clinical, and microbiological data. Mean (range) age of confirmation of diagnosis was 5.7 weeks (1-14 weeks). There was no significant difference in birth weight, genotype, immunoreactive trypsin concentration, neonatal history, symptoms at diagnosis, pancreatic enzyme supplementation, or parental smoking history between the groups. Infants in group E had more frequent cough and a greater number of Staphylococcus aureus isolates than infants in group P. More infants of group E were admitted to hospital, had higher admission rates during the second year (19 v 5), for longer periods (6.4 v 2.2 days), despite receiving more than double the number of courses of antibiotics than group P infants (in addition to flucloxacillin). Continuous prophylactic flucloxacillin from early diagnosis of cystic fibrosis is associated with improved clinical progress during the first two years of life.

Ray matrices and double-grating imaging

Ray matrices are a powerful tool for the analysis of optical systems. In this paper we extend ray matrix techniques to double-grating imaging. The general imaging equation and the lateral magnification are obtained. Two imaging phenomena are analyzed. Several special imaging systems are discussed. The method is simple but mathematically rigorous.

Conservation of structure in ATP-depleted proximal tubules: role of calcium, polyphosphoinositides, and glycine

Increases of intracellular free Ca2+ (Caf) may mediate phospholipid hydrolysis and disintegration in energy-compromised cells; on the other hand, glycine and related amino acids preserve structure. We have examined the effects of increased Caf on phospholipids and structure in ATP-depleted cells, as well as how these actions may be modified by glycine. Incubation of isolated proximal tubules with antimycin A led to ATP depletion, delayed increases of Caf to micromolar levels, polyphosphoinositide (PPI) hydrolysis by phospholipase C, and generalized disintegration of cell structure. Glycine inhibited PPI hydrolysis and preserved cell structure in entirety but did not apparently modify the Caf increases. When overwhelming increases of Caf were induced by the additional presence of a Ca2+ ionophore, glycine did not inhibit either the hydrolysis of PPI or disruption of mitochondria and microvilli. However, the cells remained integrated and unbroken. Incubation in low-Ca2+ medium prevented Caf increases, inhibited PPI hydrolysis, and preserved the structure of mitochondria and microvilli. Nevertheless, there was lethal damage by disintegration of all other membranes. This damage was prevented specifically and completely by glycine. Thus compartments of cells were shown to be differentially susceptible to injury from increased Caf or lack of glycine. Although damage by either factor occurs by distinct mechanisms, glycine also appears to have effects that suppress the deleterious effects of Ca2+ so long as Caf increases are not overwhelming. Our results also suggest that the PPI have a major structural role, which may be compromised by Caf increase during ATP depletion.

Diffraction-free beams generated with programmable spatial light modulators

Diffraction-free beams are generated by the use of diffractive optical elements written on a spatial light modulator (SLM). By alteration of the pattern placed on the SLM, the axis of propagation can be both shifted laterally and rotated. We present experimental results obtained by use of a magneto-optic SLM.

Evaluation of butorphanol tartrate and buprenorphine hydrochloride on the inflammatory reaction of the Sereny Test

Invasion of the ocular epithelia of guinea pigs by virulent Shigella organisms, eliciting keratoconjunctivitis, is the basis of the Sereny Test (ST). This test has been used to ascertain the virulence of Shigella strains and more recently to screen candidate Shigella vaccines for efficacy. This test undoubtedly causes pain in test animals; however, recommendation for use of local analgesics/anesthetics has not been accepted because of concern that these topical agents may affect the ability of the Shigella organisms to invade the ocular epithelia or have a physiologic effect on the inflammatory process. Similarly, investigators are hesitant to use systemic analgesics in conjunction with the ST. Two blinded studies were conducted to evaluate the effects of selected systemic analgesics on the ST in outbred Hartley guinea pigs. Study 1 evaluated the recommended dosages for two systemic analgesics; study groups consisted of those receiving butorphanol tartrate (n = 16), those receiving buprenorphine hydrochloride (n = 16), and untreated controls (n = 5). Study 2 evaluated a low-dose buprenorphine hydrochloride group (n = 16) and an untreated control group (n = 5). All animals were inoculated with Shigella flexneri, strain 2a 2457T, onto the cornea and conjunctiva of each eye. At the onset of clinical signs, analgesics were administered to test groups. The degree of keratoconjunctivitis was evaluated per standard procedure; animals were weighed daily. After 7 days, animals were euthanatized and the eyes were removed for histologic morphometric evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Horner efficiency of phase-only and binary phase-only filters

The Horner efficiency for the phase-only filter and binary phase-only filter used for optical pattern recognition is discussed relative to both the filter formulation algorithm and the geometry of the object. Using computer simulations, we find that up to 80% of the incident energy can result in the peak of the correlation signal under proper conditions with the phase-only filter. Experimental results are obtained by using the binary phase-only filter written onto magneto-optic spatial light modulator.

A surgical technique for bilateral cochleotomy in the Long-Evans rat

A bilateral cochleotomized surgical rat model, needed for a study involving microwave effects, was developed, standardized, and assessed for reproducibility. After a review of the literature concerning attempts and approaches with various species, a technique involving an approach through the external auditory canal was chosen and modified. Using a stereomicroscope, a cutaneous incision in the intertragic notch was made and extended medially along the ventral aspect of the external auditory canal to the depth of the external auditory meatus. The tympanic membrane was ruptured and the malleus removed with splinter forceps, allowing visualization of the cochlea. The lateral wall of the cochlea was penetrated with a 0.024-in. wire gauge drill bit and endolymph was suctioned from the cochlea. A 5-mm piece of 3-O silk suture, inserted into the cochlear opening, maintained patency. Appraisal of the reliability and standardization of the procedure was performed utilizing startleometry. Histology assessed completeness of the procedure and any evidence of cochlear infection.

Applied physiology of female soccer players

Women's soccer is in its infancy as a sport and research into its physiological demands and the physical characteristics of players is somewhat limited. There is now an increasing demand for scientific investigation of the female game and of the players, match analysis and role variations requiring particular attention. Current research suggests that the demands of the game for women are similar to those placed on male players. Women are reported to cover a similar distance (mean 8471m) to their male counterparts during a game and much the same proportions of the game appear to be devoted to exercise of varying intensities. Furthermore, female and male players appear to tax the aerobic and anaerobic energy systems to a similar level. The physical and physiological characteristics of female soccer players are comparable with those of other female games players and are more favourable than average for the population. Mean body fat percentages of between 19.7 and 22.0% and VO2max values of between 47.1 and 57.6 ml/kg/min have been reported for elite female players, while faster than average sprint times are also characteristic of them.

Benzocaine-induced methemoglobinemia attributed to topical application of the anesthetic in several laboratory animal species

In a screening study, a common benzocaine-containing anesthetic was topically applied to the following species: dogs (n = 11), domestic shorthair cats (n = 38), Long-Evans rats (n = 22), Sprague-Dawley rats (n = 11), ferrets (n = 6), rhesus monkeys (n = 10), cynomolgus monkeys (n = 10), owl monkeys (n = 10), New Zealand White rabbits (n = 18), miniature pigs (n = 9), ICR mice (n = 4), C3H mice (n = 4), and C57BL/10SnJ mice (n = 24). All animals, except mice and rats, received a 2-second spray to the mucous membranes of the nasopharynx for an estimated dose of 56 mg. A 2-second spray to rodents' oral mucous membranes delivered too great a volume of fluid for these animals; therefore, an equivalent dose was applied to the oral mucosa membranes by use of a 23-gauge needle and syringe. Initial (baseline) blood samples, as well as 4 blood samples taken every 15 minutes after drug application, were analyzed for methemoglobin (MHb), using an oximeter. Positive MHb response (> 3 SD above baseline) was seen in individuals of all groups. The study was repeated in dogs several months later to confirm low response. Response to benzocaine spray was observed in most animals tested, with response peaking between 15 and 30 minutes after dosing. Positive MHb response ranged from 3.5 to 38%, was detected in > 95% of individual animals, and ranged from 15 to 60 minutes after drug administration.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of food on the absorption and metabolism of drugs

Food-drug interactions can lead to a loss of therapeutic efficacy or toxic effects of drug therapy. Generally, the effect of food on drugs results from a reduction in the drug's bioavailability; however, an alteration in drug clearance can occur due to the effect of certain foods on drug metabolism. The proportion of adverse drug reactions due to food-drug interactions is not known and unfortunately only when a serious adverse drug reaction follows a food-drug interaction does the matter usually receive any significant attention. In order to improve therapeutic efficacy and to help prevent adverse drug reactions, it is necessary that clinicians be knowledgeable of the important food-drug incompatibilities and risk factors related to the increased likelihood of developing an adverse drug reaction due to food-drug interactions.

Anatomical and roentgenographic features of atlantooccipital instability

An anatomical study using six fresh, human cadaveric cervical spine specimens was performed. After the dissection of all soft tissue, flexion-extension radiographs were obtained to verify initial stability. A sagittal plane bone cut was then made, centered on the odontoid and sparing the alar ligaments, the tectorial membrane, and the atlantooccipital (AO) ligaments. Repeat flexion-extension radiographs and photographs were taken to document maintenance of stability of these hemisections. The occipital-atlantoaxial ligaments were then individually and sequentially incised, maintaining all other structures each time. After the sectioning of each ligament, flexion-extension radiographs and photographs were obtained to identify subsequent motion patterns. Both gross anatomical and roentgenographic examinations demonstrated the important stabilizing role of the tectorial membrane in flexion. Additionally, contact between the posterior arch of C1 and the occiput limited hyperextension as a secondary restraint once the tectorial membrane was sectioned. Furthermore, the AO ligaments proved to play an insignificant role in the preservation of AO stability through a flexion-extension arc of motion. Under normal circumstances, the AO articulation is not excessively stressed. However, acute AO injury, as well as the insidious failure of these ligaments, has been documented in several cases involving various pathologies. This study demonstrates a mechanism of instability and highlights the essential role of the tectorial membrane in maintaining upper cervical spine stability.

Ray-matrix approach for diffractive optics

Ray matrices are a powerful tool for the analysis of optical systems. This technique is modified to include a diffractive optical element within the optical system. Several research applications are discussed, including optical Fourier transforms and imaging with diffractive optical elements.

Uvulopalatopharyngoplasty for obstructive sleep apnea in adults: clinical correlation with polysomnographic results

The success of Uvulopalatopharyngoplasty (UPPP) for Obstructive Sleep Apnea (OSA) can be assessed by a variety of parameters including clinical evaluation and polysomnography (PSG). Patients are often reluctant to undergo post-operative testing and insurance companies are often unwilling to reimburse for expensive overnight sleep studies. Due to the reality of these medical and economical problems, can a clinician be confident of the success of UPPP based solely on clinical evaluation? Sixty patients underwent UPPP for the treatment of OSA from July 1987 through June 1992. Patients treated with tracheostomy or other methods were not included in this study. Fifty-three patients (88%) reported an improvement in their symptoms of snoring, daytime somnolence, morning headache and apnea. Twenty-one patients (35%) had post-operative PSG. Eighteen of 21 patients (85%) reported improvement in their symptoms. Eleven of 21 patients (57%) showed objective improvement in their sleep apnea. The objective findings of PSG do not correlate, in a significant number of patients, with subjective clinical improvement of patients treated with UPPP.