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At least 487 records · Page 27Linked to original sources
PubMed2000

Herbacic acid, a simple prototype of 5,5,5-trichloroleucine metabolites from the sponge Dysidea herbacea.

Dysidea herbacea, collected at Harrier Reef on the Great Barrier Reef, contains the novel metabolite herbacic acid as the major trichloroleucine metabolite. Herbacic acid appears to be an early product of direct free-radical chlorination of leucine and is a prototype for further transformation of the free carboxylic acid group and generation of complex trichloromethyl metabolites, including natural products of the dysidenin family.

Amino Acids↗
PubMed1997

Safety, functionality and acceptability of a prototype polyurethane condom.

Male condoms made from synthetic materials offer an alternative to latex condoms that may be more acceptable to users, thereby potentially resulting in more protected acts of intercourse. A prospective, noncomparative clinical study was conducted to evaluate the safety of using certain polyurethane materials to make condoms. Fifty-one healthy, contracepting, mutually monogamous couples were recruited between June 30 and November 24, 1993 to use a prototype roll-on polyurethane condom developed by Family Health International. Couples were to use the condoms for 10 consecutive acts of vaginal intercourse over a 4-week period. Baseline and postexposure genital examinations, including colposcopy for female participants, were performed. Fifty couples completed the study requirements and 517 acts of intercourse occurred using the condoms. Two adverse events were reported: irritation of introitus in a female participant and a small irritated erythematous lesion on a male participant's penis. Neither event was considered to be serious and both were resolved without treatment. Breakage and slippage rates were similar to those reported for latex condoms. These results suggest that polyurethane condoms represent a safe, functional and acceptable alternative to latex condoms.

Adult↗
PubMed1999

Performance of the frameless IUD (Flexigard prototype inserter) and the TCu380A after six years as part of a WHO multicenter randomized comparative clinical trial in parous women.

The clinical performance of the new Frameless IUD was compared with the TCu380A, the most widely used copper IUD in the world today. Insertions of the Frameless IUD were conducted with a prototype inserter (Flexigard). We report on the 6-year results from a randomized comparative clinical trial conducted at the Shanghai Institute of Planned Parenthood Research, as part of an international multicenter WHO clinical trial, involving 200 women, respectively recruited for use of each device. The cumulative 6-year pregnancy rates were 0.0 per 100 women for the Frameless IUD and 3.3 for TCu380A. Termination due to partial expulsion was significantly less for the Frameless IUD as compared with TCu380A (0.0 and 4.3 per hundred women, respectively). Complete expulsion, bleeding, pain, bleeding and pain and other medical reasons for termination did not differ significantly between the two devices. The net cumulative continuation rates at six years per 100 women were 80.8 for TCu380A, and 83.0 for the Frameless IUD. Both Frameless IUD and TCu380A are highly effective, safe and acceptable contraceptive devices, because of low pregnancy rates (per 100 women), and low termination rates due to expulsion, pain, bleeding, and bleeding and pain. Due to its anchoring, the Frameless IUD is significantly more effective than the TCu380A IUD as regards proper retention of the IUD in the uterine cavity. This may also explain its lower failure rate.

Adult↗
PubMed2000

A prototype device for standardized calibration of pulse oximeters.

OBJECTIVE: To develop and test a method for standardized calibration of pulse oximeters. METHODS: A novel pulse oximeter calibration technique capable of simulating the behavior of real patients is discussed. It is based on an artificial finger with a variable spectral-resolved light attenuator in conjunction with an extensive clinical database of time-resolved optical transmission spectra of patients fingers in the wavelength range 600-1000 nm. The arterial oxygen saturation of the patients at the time of recording was derived by analyzing a corresponding blood sample with a CO-oximeter. These spectra are used to compute the modulation of the light attenuator which is attached to the artificial finger. This calibration method was tested by arbitrarily playing back recorded spectra to pulse oximeters and comparing their display to the value they displayed when the spectra were recorded. RESULTS: We were able to demonstrate that the calibrator could generate physiological signals which are accepted by a pulse oximeter. We also present some experience of playing back recorded patient spectra. The mean difference between the original reading of the pulse oximeters and the display when attached to the calibrator is 1.2 saturation points (displayed oxygen saturation SpO2) with a standard deviation of 1.9 saturation points. CONCLUSIONS: The tests have shown the capabilities of a spectral light modulator for use as a possible calibration standard for pulse oximeters. If some improvements of the current prototype can be achieved we conclude from the experience with the device that this novel concept for the calibration of pulse oximeters is feasible and that it could become an important tool for assessing the performance of pulse oximeters.

Calibration↗
PubMed2001

Auto-sensuous shapes: prototypes for creative forms.

The author looks at some of the more normative, adaptive, and creative aspects of what have been called 'autistic' or 'auto-sensuous' shapes by Tustin and others. She explores the construct from several frameworks, including the literature on early sensory experience and that on the empathic attunement between infant and caretaker in which interpersonal rhythms and meanings are built. The views of Bion and Matte-Blanco are utilized to help explore the processes by which meaning is created from experience, while the works of Segal and Milner are used to focus more explicitly on the role of symbol formation in the creative process. Finally, it is suggested that these auto-sensuous shapes can become prototypes for creative endeavours, including the creative process we call psychoanalysis. The author uses examples from her own experience in deriving pattern from basic sensory experience, toward the creation of poetry, drawings, and the establishment of attunement and 'meaning-making' within the analytic setting.

Child↗
PubMed1993

Human transbuccal absorption of diclofenac sodium from a prototype hydrogel delivery device.

The buccal delivery of the nonsteroidal antiinflammatory drug, diclofenac sodium (Voltaren), from a prototype hydrogel was studied in man in a randomized crossover design of buccal delivery and i.v. infusion. After a 30-min delay, plasma levels of diclofenac increased to near steady-state levels of 100 ng/ml by 3 hr. With each subject serving as his own control, the i.v. infusion data facilitated the calculation of a mean steady-state flux of diclofenac sodium of 2.1 +/- 0.6 mg/cm2-hr across human buccal mucosa and a time lag of 1.0 +/- 0.5 hr. The large flux of this ionized species indicates that the traditional lipoidal model of buccal permeation based on the partition coefficient is inadequate.

Absorption↗
PubMed2000

Light-guided intubation via the intubating laryngeal mask using a prototype illuminated flexible catheter. Clinical experience in 400 patients.

BACKGROUND: The transillumination of the soft tissues of the neck using lighted stylets has been used as an aid for tracheal intubation. We evaluated the efficacy and safety of a prototype illuminated flexible catheter to facilitate light-guided intubation through the intubating laryngeal mask. METHODS: The illuminated flexible catheter consists of a completely flexible thin plastic catheter with a bulb attached to its distal end. The device was placed into a silicone tracheal tube in such a way that the bulb was adjusted at the distal end of the tracheal tube. The tracheal tube preloaded with the device was inserted through the intubating laryngeal mask and, by observing the glow on the neck, was advanced into the trachea. We report our experience with light-guided intubation through the intubating laryngeal mask in 400 ASA grade 1-3 patients undergoing general anaesthesia. RESULTS: The intubating laryngeal mask was inserted successfully in all patients. The overall intubating success rate was 99.8% (399/400); in 367 (91.8%) cases at the first attempt, in 28 (7%) at the second, in 4 (1%) at the third and in one case (0.2%) at the fifth attempt. There were 27 patients with potentially difficult airways. All these cases were intubated successfully; in 23 of 27 (85.2%) at the first attempt, in 3 of 27 (11.1%) at the second and one of 27 patients (3.7%) at the third attempt. CONCLUSION: We conclude that the use of the illuminated flexible catheter facilitates the intubation through the intubating laryngeal mask. The suggested light-guided intubating method proved to be a simple, safe and effective technique.

Adolescent↗
PubMed2000

Comparison of a double-textured prototype manual toothbrush with 3 branded products. A professional brushing study.

BACKGROUND: The consensus has been that there is no one superior design of manual toothbrush for plaque removal, despite, in some cases, encouraging findings from laboratory studies. The user appears the major variable and may mask differences in brush efficacy. AIMS: The aim of this study was to compare 2 new double-filament texture brushes with 3 established brands for plaque removal, under standardised conditions of professional brushing. METHOD: The study was a blind, randomised crossover design, balanced for residual effects. A panel of 15 subjects suspended tooth cleaning for 3 days. On day 4, plaque was scored from 6 sites per tooth before and after a 2-min professional toothbrushing. A washout period of at least 3 days was allowed between study periods. RESULTS: Overall plaque removal was 50% with no significant differences between brushes, a 3% absolute difference in average total mouth plaque separating brushes. However, at upper- and mid-buccal sites, a not significant 8% and a significant 9% difference, respectively, in plaque removal were recorded in favour of one of the prototype brushes, and at the mid-lingual site, there was a non-significant 10% difference in favour of one branded brush. Other sites were cleaned similarly by all brushes except for reduced plaque removal from buccal compared to lingual surfaces and interproximal compared to mid-surface sites. Highly significant subject differences in plaque removal were noted which may be relevant to inherent anatomical difficulties in tooth cleaning for some individuals. Period effects were not significant, supporting the consistency in brushing by the professional brusher. CONCLUSION: The method appeared capable of detecting small benefits of brush design. However, the benefits reported must be taken within the context of an overall lack of difference between brushes. The method could be used to set and record a minimum level of efficacy for toothbrushes.

Adult↗
PubMed2001

Clinical application of computer-aided rapid prototyping for tooth transplantation.

The maintenance of healthy periodontal ligament cells in the donor tooth is one of the most important factors for successful tooth transplantation. This is achieved by minimizing the extraoral time during the surgical procedure. If a duplicate form of donor tooth could be obtained before extraction, it would be possible to precontour the recipient alveolar bone compatible with the donor tooth, and thereby reduce the extra-oral time of the donor tooth. We obtained a three-dimensional image with the real dimensions of the donor tooth from a CT Highspeed Advantage, allowing a life-sized resin model of the tooth to be fabricated. From 22 clinical cases, we achieved an average total transplantation time of 7.7 min. The average distance between the transplanted root surface and the alveolar bone from 12 available cases was 0.87 mm at the mesial cervix, 0.91 mm at the mesial apex, 0.98 mm at the distal cervix and 1.16 mm at the distal apex on the postoperative radiographs. Clinical data indicate that computer-aided rapid prototyping may be of value in minimizing the extra-oral time and possible injury to transplanted tooth during the process of autotransplantation.

Adult↗
PubMed1999

Evolutionary versus prototype analyses of the concept of disorder.

The harmful dysfunction (HD) analysis of the concept of disorder (J. C. Wakefield, 1992a) holds that disorders are harmful failures of internal mechanisms to perform their naturally selected functions. S. O. Lilienfeld and L. Marino (1995) proposed instead that disorder is a Roschian prototype concept without defining properties. Against the HD analysis, they argued that many disorders are not failures of naturally selected functions because they are either designed reactions (e.g., fever) or failures of functions that are not naturally selected (e.g., reading disorder). The HD analysis is defended here against these and other objections and compared with the Roschian account. It is argued that the objections are based on conceptual confusions and can be turned around to provide strong new support for the HD analysis. A series of conceptual experiments demonstrates the superior explanatory power of the HD analysis and disconfirms the Roschian account.

Biological Evolution↗
PubMed1986

Learning and memory for personality prototypes.

Although personality traits are commonly assumed to be represented in memory as schemata, little research has addressed whether such schemata can be learned from observation. Subjects in three studies classified 60 person instances into group members and nonmembers as defined by the instances' match to a complex personality prototype. To simulate learning of fuzzy categories, each person instance provided conflicting cues to group membership. Learning for instances' group membership was excellent across studies. In Study 1, frequency of cues indicating group membership was greatly overestimated among nongroup instances. In Study 2, schema-consistent memory bias was revealed for person instances. In Study 3, schemata of consistently positive (or negative) traits were learned faster than arbitrary schemata. The findings implicated frequency sensitivity of memory (Estes, 1986), and a model of probabilistic cued-memory retrieval was developed to account for the effects. The findings were then discussed in relation to everyday cognitive performance.

Adult↗
PubMed1996

Influence of prototypes on perceptions of prejudice.

Two studies examined the influence of cultural stereotypes and personal factors (one's race, gender) on perceptions of racial and gender discrimination. Overall, the data suggest that our perceptions of prejudice are strongly influenced by specific expectations regarding who are the prototypic perpetrators and victims of prejudice. More general expectations regarding out-group conflict or regarding only the characteristics of the perpetrator appear to have less of an impact on such perceptions. Additionally, women were found to be more likely than men to perceive sexism directed against men and racism directed at African Americans and Caucasians. Also, African Americans were more likely than Caucasians to perceive racist events against Whites and Blacks. The implications of these data are discussed.

Adult↗
PubMed1991

An experimental evaluation of a prototype public access nutrition information system for supermarkets.

Located the Nutrition for a Lifetime System (NLS-1), a prototype interactive information system, in a large supermarket to help users decrease high-fat food purchases and increase high-fiber food purchases. Study participants were randomly assigned to control (n = 23; used the NLS-1 to enter food purchases only) or experimental (n = 26; viewed videodisc instructional programs, received prompts, made commitments, received feedback from the NLS-1) conditions. According to data entered in the NLS-1 and actual food shopping receipts, experimental participants significantly reduced higher fat purchases. Increases in higher fiber purchases favored the experimental group but were not significant.

Adult↗
PubMed1989

An on-line investigation of prototype and exemplar strategies in classification.

Although prototype- and exemplar-based models of categorization are very different in character, they have proved difficult to distinguish experimentally. The research described here presents a priming technique for assessing the type of information retrieved at the moment that a categorization decision is made. This technique avoids many of the problems inherent in the standard paradigms. Data from six experiments are presented that demonstrate the usefulness of the technique and also address basic questions about the categorization process. Results bolster previous suggestions that categorization strategies may be mixed within a single experimental task and highlight the need for more specific predictions about when each strategy will come into play.

Adult↗
PubMed2000

Rapid prototyping of patterned functional nanostructures

Living systems exhibit form and function on multiple length scales and at multiple locations. In order to mimic such natural structures, it is necessary to develop efficient strategies for assembling hierarchical materials. Conventional photolithography, although ubiquitous in the fabrication of microelectronics and microelectromechanical systems, is impractical for defining feature sizes below 0.1 micrometres and poorly suited to pattern chemical functionality. Recently, so-called 'soft' lithographic approaches have been combined with surfactant and particulate templating procedures to create materials with multiple levels of structural order. But the materials thus formed have been limited primarily to oxides with no specific functionality, and the associated processing times have ranged from hours to days. Here, using a self-assembling 'ink' we combine silica-surfactant self-assembly with three rapid printing procedures--pen lithography, ink-jet printing, and dip-coating of patterned self-assembled monolayers--to form functional, hierarchically organized structures in seconds. The rapid-prototyping procedures we describe are simple, employ readily available equipment, and provide a link between computer-aided design and self-assembled nanostructures. We expect that the ability to form arbitrary functional designs on arbitrary surfaces will be of practical importance for directly writing sensor arrays and fluidic or photonic systems.

Journal Article↗
PubMed2001

A prototype storage ring for neutral molecules.

The ability to cool and manipulate atoms with light has yielded atom interferometry, precision spectroscopy, Bose-Einstein condensates and atom lasers. The extension of controlled manipulation to molecules is expected to be similarly rewarding, but molecules are not as amenable to manipulation by light owing to a far more complex energy-level spectrum. However, time-varying electric and magnetic fields have been successfully used to control the position and velocity of ions, suggesting that these schemes can also be used to manipulate neutral particles having an electric or magnetic dipole moment. Although the forces exerted on neutral species are many orders of magnitude smaller than those exerted on ions, beams of neutral dipolar molecules have been successfully slowed down in a series of pulsed electric fields and subsequently loaded into an electrostatic trap. Here we extend the scheme to include a prototype electrostatic storage ring made of a hexapole torus with a circumference of 80 cm. After injection, decelerated bunches of deuterated ammonia molecules, each containing about 106 molecules in a single quantum state and with a translational temperature of 10 mK, travel up to six times around the ring. Stochastic cooling might provide a means to increase the phase-space density of the stored molecules in the storage ring, and we expect this to open up new opportunities for molecular spectroscopy and studies of cold molecular collisions.

Journal Article↗
PubMed1994

Drug excretion mediated by a new prototype of polyspecific transporter.

Cationic drugs of different types and structures (antihistaminics, antiarrhythmics, sedatives, opiates, cytostatics and antibiotics, for example) are excreted in mammals by epithelial cells of the renal proximal tubules and by hepatocytes in the liver. In the proximal tubules, two functionally disparate transport systems are involved which are localized in the basolateral and luminal plasma membrane and are different from the previously identified neuronal monoamine transporters and ATP-dependent multidrug exporting proteins. Here we report the isolation of a complementary DNA from rat kidney that encodes a 556-amino-acid membrane protein, OCT1, which has the functional characteristics of organic cation uptake over the basolateral membrane of renal proximal tubules and of organic cation uptake into hepatocytes. OCT1 is not homologous to any other known protein and is found in kidney, liver and intestine. As OCT1 translocates hydrophobic and hydrophilic organic cations of different structures, it is considered to be a new prototype of polyspecific transporters that are important for drug elimination.

Amino Acid Sequence↗
PubMed2000

Structural analysis of WW domains and design of a WW prototype.

Two new NMR structures of WW domains, the mouse formin binding protein and a putative 84.5 kDa protein from Saccharomyces cerevisiae, show that this domain, only 35 amino acids in length, defines the smallest monomeric triple-stranded antiparallel beta-sheet protein domain that is stable in the absence of disulfide bonds, tightly bound ions or ligands. The structural roles of conserved residues have been studied using site-directed mutagenesis of both wild type domains. Crucial interactions responsible for the stability of the WW structure have been identified. Based on a network of highly conserved long range interactions across the beta-sheet structure that supports the WW fold and on a systematic analysis of conserved residues in the WW family, we have designed a folded prototype WW sequence.

Amino Acid Sequence↗