Showing papers by "James Taylor published in 1998"

In vivo expression of therapeutic human genes for dopamine production in the caudates of MPTP-treated monkeys using an AAV vector

Abstract: An adeno-associated virus (AAV) vector, expressing genes for human tyrosine hydroxylase (TH) and aromatic amino acid decarboxylase (AADC), demonstrated significantly increased production of dopamine in 293 (human embryonic kidney) cells. This bicistronic vector was used to transduce striatal cells of six asymptomatic but dopamine-depleted monkeys which had been treated with the neurotoxin MPTP. Striatal cells were immunoreactive for the vector-encoded TH after stereotactic injection for periods up to 134 days, with biochemical effects consistent with dopamine biosynthetic enzyme expression. A subsequent experiment was carried out in six more severely depleted and parkinsonian monkeys. Several TH/aadc-treated monkeys showed elevated levels of dopamine near injection tracts after 2.5 months. Two monkeys that received a β-galactosidase expressing vector showed no change in striatal dopamine. Behavioral changes could not be statistically related to the vector treatment groups. Toxicity was limited to transient fever in several animals and severe hyperactivity in one animal in the first days after injection with no associated histological evidence of inflammation. This study shows the successful transfection of primate neurons over a period up to 2.5 months with suggestive evidence of biochemical phenotypic effects and without significant toxicity. While supporting the idea of an in vivo gene therapy for Parkinson’s disease, more consistent and longer lasting biochemical and behavioral effects will be necessary to establish the feasibility of this approach in a primate model of parkinsonism.

Formula Supplementation With Long-chain Polyunsaturated Fatty Acids: Are There Developmental Benefits?

Abstract: Objective. To evaluate the developmental outcomes of children who participated in an augmented randomized clinical trial of supplementing a standard infant formula with long-chain polyunsaturated fatty acids. Design. Randomized clinical trial, augmented with a nonrandomized human milk comparison group. There were three randomized formula groups: standard formula, standard formula containing docosahexaenoic acid (DHA), and standard formula containing DHA and arachidonic acid. Setting. Three clinical sites serving diverse populations: Kansas City, MO; Portland, OR; and Seattle, WA. Participants. A total of 274 healthy full-term infants were enrolled in the infant-feeding protocol; of these, 197 (72%) participated in assessments of developmental outcome. Formula Supplements. In the randomized trial, one group received a standard formula, another group received a formula that had been supplemented with DHA from fish oil, and a third group received a formula supplemented with both DHA and arachidonic acid from an egg phospholipid. Outcome Measures. Mental and Motor Scales of the Bayley Scales of Infant Development at 12 months of age; vocabulary and gesture communication scores from the MacArthur Communicative Development Inventories at 14 months of age. Results. There were no statistically significant differences for either the Bayley Mental Scale or the Bayley Motor Scale, neither when the analysis was restricted to the three randomized formula groups nor when the analysis included all four groups. However, the DHA formula group had significantly lower scores on two of the MacArthur scales: the DHA group scored lower than the nonrandomized human milk comparison group on the Vocabulary Comprehension Scale, and the DHA group scored lower than the randomized control formula group on the Vocabulary Production Scale. Moreover, additional analyses both in the formula groups and in the human milk comparison group found significant negative correlations between DHA levels and vocabulary outcomes. Conclusion. We believe that additional research should be undertaken before the introduction of these supplements into standard infant formulas.

Prevalence of Clinical Sinusitis in Young Children Followed Up by Primary Care Pediatricians

Abstract: OBJECTIVE To determine the proportion of young children seen in primary care pediatric practices who meet clinical criteria for the diagnosis of sinusitis, and variations in the management of these patients' conditions. DESIGN Observational cohort study. SETTINGS Pediatric practices in the Seattle, Wash, area participating in the Puget Sound Pediatric Research Network, a regional practice-based research organization. PATIENTS Children, 1 to 5 years old, presenting for any reason to participating practices. METHODS Parents of all 1307 eligible children completed a survey specifically detailing the presence of nasal congestion or discharge and daytime cough, the duration of these symptoms, and whether the symptoms were improving. For patients meeting clinical criteria for sinusitis (nasal congestion and daytime cough persisting for > 9 days without improvement), the pediatrician recorded the presence/severity of other signs and symptoms, and the treatment prescribed. Severity of symptoms was reassessed using telephone interviews with parents at 48 to 72 hours, and again at 10 to 14 days, after the office visit. Study data were collected during 1-week to 3-week blocks at each office site during the winter months. RESULTS Data were collected on 1307 children; 121 had persistent respiratory symptoms meeting criteria for a diagnosis of sinusitis (9.3%, 95% confidence interval, 7.7%-10.9%). Patients who presented with cold/cough symptoms were significantly more likely to meet criteria for sinusitis than those who came for any other reason (17.3% vs 4.2%, respectively, P < .001). A physician study form was completed on 87 children with persistent symptoms; antibiotics were prescribed for 68 (78%) of these patients. Antibiotic-treated patients were more likely to have symptoms lasting longer than 29 days (P = .004) and to have purulent nasal discharge (P = .03), and were judged to be sicker at enrollment (P = .001) than untreated children. A concurrent otitis media was diagnosed in 40 (46%) of 87 patients; if the proportion of children with otitis media is excluded, 5% of children 1 to 5 years old who are seen in primary care pediatrics might be expected to receive antibiotics exclusively for a diagnosis of sinusitis. At 24 to 48 hours and at 10 to 14 days after the clinic visit, a trend was noted toward more rapid improvement among those children who were treated with antibiotics. CONCLUSION When the criteria are strictly adhered to, only a small proportion of young children seen during the winter months in primary care pediatric practices will be diagnosed with sinusitis.

Prefrontal cortical involvement in phencyclidine-induced activation of the mesolimbic dopamine system: behavioral and neurochemical evidence

Abstract: Acute administration of phencyclidine to rats potently activates mesocorticolimbic dopaminergic neurons. The activation of dopamine release and utilization in the prefrontal cortex and nucleus accumbens are associated with profound cognitive impairment and hyperlocomotion, respectively. This dopaminergic activation by phencyclidine is not mediated by direct effects on the cell body regions of the dopamine neurons; however, phencyclidine augments dopamine release locally in the terminal fields. In the present study, the possible involvement of the prefrontal cortex in mediating activation of the mesolimbic dopamine system by phencyclidine was examined. Ibotenic acid lesions of the prefrontal cortex attenuated the biochemical activation of the mesolimbic dopamine neurons by PCP, and prefrontal lesions sharply blunted phencyclidine-, but not amphetamine- or novelty-, induced hyperlocomotion. In addition, injection of phencyclidine directly into the prefrontal cortex increased dopamine utilization in the nucleus accumbens and induced hyperlocomotion. In summary, these studies show that phencyclidine activates the mesolimbic pathway through a mechanism in the prefrontal cortex, possibly by disinhibiting the cortical circuit and activating corticofugal glutamatergic release in the ventral tegmental area.

Raman fibre laser operating at 1.24 [micro sign]m

Abstract: A compact and efficient cascaded Raman fibre laser based on fused fibre couplers pumped by a diode-pumped ytterbium-doped fibre laser is demonstrated. The results obtained from its application to various Raman amplifier configurations at 1300 nm are reported.

Reactions of Pediatricians to the Recommendation for Universal Varicella Vaccination

Abstract: Objectives To determine the rate of self-reported adherence by pediatricians to the 1995 American Academy of Pediatrics and the Advisory Committee on Immunization Practices varicella immunization recommendations and to evaluate factors that might influence adherence. Design Mail survey. Setting and Participants Washington State pediatricians. Main Outcome Measure Logistic regression was used to identify demographic characteristics, attitudes about varicella vaccine, and previous experiences with the disease that were associated with self-reported adherence to universal varicella immunization recommendations. Results Completed surveys were returned by 76% of contacted pediatricians, of whom 42% reported following a policy of universal varicella immunization. In multivariate analysis, agreement with statements regarding the effectiveness of varicella vaccine in reducing rare but serious complications of the disease (odds ratio [OR], 4.90; 95% confidence interval [CI], 2.30-10.50) and in decreasing work loss by parents (OR, 4.21; 95% CI, 1.14-15.50) were associated with recommending universal immunization. Disagreement with statements concerning the lack of the need for varicella immunization because complications are rare (OR, 2.54; 95% CI, 1.12-5.74), it is not required for school entry (OR, 2.52; 95% CI, 1.37-4.64), and it is not medically cost-effective (OR, 2.25; 95% CI, 1.21-4.18) were also associated with universally recommending the vaccine. In addition, experience with varicella encephalitis was also associated with adherence to the recommendations (OR, 1.96; 95% CI, 1.06-3.65). Conversely, those who were concerned that varicella vaccine might not provide lifelong immunity were less likely to report recommending universal vaccination (OR, 0.36; 95% CI, 0.19-0.68). Conclusions Fewer than 50% of responding Washington State pediatricians reported recommending universal varicella vaccination. Adherence to the recommendations appears to be influenced by personal experience, perceptions about the potential seriousness of varicella, and beliefs about the societal and medical cost-effectiveness of varicella vaccine.

Imaging of photogenerated acid in a chemically amplified photoresist

Abstract: Chemically amplified photoresists are widely used throughout the semiconductor industry due to the need for high throughput in the lithography process. Knowledge of the location of acid molecules in chemically amplified resists is of paramount importance for the process control of the image formation of almost all the lithographic techniques used in the semiconductor industry today. We have demonstrated a technique based on pH-dependent fluorescence which can measure directly the spatial distribution of the photoacid in photoresist films without the need of any other subsequent process after exposure. By adding a small amount of fluorescent material to the resist, a latent image can be formed when photogenerated acid molecules quench the fluorescence in exposed areas. We demonstrate images formed after exposure of SAL605 resist films to x-ray radiation, with no post-exposure bake, and show that the optical contrast is a function of dose. We also show that the same technique can be utilized for rapid evalu...

Group well-child care for high-risk families: maternal outcomes.

Abstract: Objective To determine if participation in group sessions as part of health supervision visits for infants improves outcomes compared with individual visits in high-risk mothers. Study design Randomized controlled clinical trial. Participants Mothers of young infants who had at least 1 of the following risk factors: aged younger than 20 years at delivery, participation in Medicaid, less than a high school education, previous or ongoing substance abuse, or history of abuse as a child. Setting Two urban university pediatric clinics in Seattle, Wash. Interventions Mother-infant dyads were randomized to receive group well-child care (GWCC) or individual well-child care (IWCC) before the infant was 4 months old; the intervention continued until the child was 15 months old. Mothers completed the Sense of Competence and Social Isolation subscales from the Parenting Stress Index and Sarason's Social Support Questionnaire at enrollment and again on completion of the study. During the 11-month study period, 7 health supervision visits were scheduled for each mother-infant dyad. Social workers met periodically with mothers during the study and assessed the following functional outcomes: return to school, return to work, enrollment in a substance abuse treatment program, and becoming pregnant. In addition, data on study children were collected from Child Protective Services to assess referrals because of suspected abuse and/or neglect. Results Data were collected on 213 mother-infant dyads, including 108 who received GWCC and 105 who received IWCC. At the conclusion of the study period, similar proportions of GWCC and IWCC mothers scored in the high-risk range on the Sense of Competence subscale, Social Isolation subscale, and the Social Support Questionnaire ( P =.57, .32, and .59, respectively). For more than 50% of the mothers, scores on the Sense of Competence and Social Isolation subscales deteriorated during the study period from the not-high-risk range to the high-risk range, regardless of assignment to GWCC or IWCC. No differences were noted between GWCC and IWCC mothers for any functional outcome. During the study period, 8.8% of children receiving GWCC were referred to Child Protective Services vs 8.3% of those receiving IWCC ( P =.85). Conclusion The format of well-child care may not be an important determinant of outcomes among high-risk mothers.

All-solid-state compact high repetition rate modelocked Cr4+:YAG laser

Abstract: The authors report a compact, high repetition rate, all-solid-state Kerr-lens modelocked Cr4+:YAG laser, pumped by either a diode-pumped Nd:YVO4 laser or a diode-pumped Yb-doped fibre laser. Femtosecond pulses have been obtained, tunable from 1.505 to 1.550 µm, with single beam modelocked average output powers as high as 280 mW at repetition rates of up to 1 GHz.

Combining forecast quantiles using quantile regression: Investigating the derived weights, estimator bias and imposing constraints

Abstract: A novel proposal for combining forecast distributions is to use quantile regression to combine quantile estimates. We consider the usefulness of the resultant linear combining weights. If the quantile estimates are unbiased, then there is strong intuitive appeal for omitting the constant and constraining the weights to sum to unity in the quantile regression. However, we show that suppressing the constant renders one of the main attractive features of quantile regression invalid. We establish necessary and sufficient conditions for unbiasedness of a quantile estimate, and show that a combination with zero constant and weights that sum to unity is not necessarily unbiased.

Dynamic optimal reactive power flow

Abstract: An efficient method for minimization of energy loss over time is presented. The proposed method uses different loading conditions during a given future time interval instead of one single snapshot of the network. The method finds the optimal conditions during the given interval. The given interval is divided into several shorter periods. By increasing the number of periods or load profiles, the dimension of the problem will rise substantially. This problem is handled by using the generalized Bender decomposition (GBD) technique. With this technique, the loading condition for each period are solved in a separate NLP subproblem. The results of the NLP subproblems are coordinated in a master problem. As shown in simulation results, the proposed method not only improves the voltage profile, but it also decreases the total energy loss over the given interval.

Broadband silica fibre Raman amplifiers at 1.3 /spl mu/m and 1.5 /spl mu/m

Abstract: High power fibre lasers operating at 1.24 /spl mu/m and 1.42 /spl mu/m respectively have been used to provide broad band Raman gain around 1.3 /spl mu/m and 1.5 /spl mu/m in compact, efficient, silica fibre-amplifier configurations. The gain and noise performance of these broad band amplifiers are described as well the mechanism to further increase and flatten the operational bandwidths.

On-wafer photoacid determination and imaging technique for chemically amplified photoresists

Abstract: A fundamental task of chemically amplified photoresists is to record the incident radiation by generating catalyst concentration gradients within the film. In many resists, the catalyst is a strong Bronsted acid which yields a latent image of pH within the exposed film. A number of mechanistic questions remain about acid generator efficiency and its mobility once generated and heated. We have developed a technique in which a pH-dependent fluorophore is incorporated into the resist (an undyed version of SAL 605 from the Shipley Company and similar formulations). The localized acid concentrations generated by exposure to x-rays are analyzed and imaged using fluorescence spectroscopy and microscopy. Initial experiments, the spectroscopic apparatus, and initial far-field imaging are reported elsewhere [S. J. Bukofsky, G. D. Feke, Q. Wu, R. D. Grober, P. M. Dentinger, and J. W. Taylor, Appl. Phys. Lett. 73, 3 (1998)]. In this article, several fluorophores are evaluated, and various criteria for successful imag...

All-fibre periodic spectral filter for simultaneous generation of multiple WDM channels from broad bandwidth pulsed sources

Abstract: An all-fibre spectral filter is demonstrated for the simultaneous generation of several wavelength division multiplexed (WDM) pulsed sources using the spectral slicing technique. More than 10 WDM channels, each with a base rate of 10 GHz, are generated from a single 190 fs pulse train.

Second harmonic generation around 0.53 /spl mu/m of seeded Yb fibre system in periodically-poled lithium niobate

Abstract: Fibre-integrated, seeded, high-power Yb-doped fibre amplifiers have been used in combination with periodically-poled lithium niobate crystals in simple experimental configurations to give second harmonic generation to the visible both in CW and pulsed formats with conversion efficiencies as high as 41% in compact configurations.

Ultra-broad-bandwidth spectral continuum generation in fibre Raman amplifier

Abstract: Picosecond seeding pulses derived from a CW source and electroabsorption modulator operating at a 10 GHz repetition rate have been used with gain saturation and nonlinear conversion in a high power fibre Raman amplifier to provide a broad-band, 100 nm, spectral continuum with an average power > 1W.

Theoretical modeling of gain-guiding effects in experimental all-solid-state KLM lasers

Abstract: All-solid-state four-mirror Kerr lens mode locked (KLM) Cr:LiScGaAlF/sub 6/ and three-mirror Cr:YAG femtosecond lasers have been experimentally developed and theoretically analyzed, using a numerical model that takes into account astigmatism, nonlinear xy coupling, and gain-guiding. For the soft-aperture three-mirror KLM system, the model is extended to include gain saturation and soft-aperturing and a new optimization parameter is proposed.

The Second Cambridge Pulsar Survey At 81.5 MHz

Abstract: We have searched the northern sky for pulsars at the low radio frequency of 81.5 MHz, using the 3.6 hectare array at Cambridge, England. The survey covered most of the sky north of declination -20° and provided sensitivities of order 200 mJy for pulsars not too close to the Galactic plane. A total of 20 pulsars were detected, all of them previously known. The effective postdetection sampling rate was 1.3 kHz, and the sensitivity to low-dispersion millisecond pulsars was sufficient to allow the detection of objects similar to PSR J0437-4715 (period 5.7 ms, dispersion measure 2.6 cm-3 pc, mean flux density ~1 Jy). No such pulsars were found.

Axially chiral cyclopentadienyl ligands: stereoselective synthesis of 1-substituted-9-(1′-naphthyl)fluorenes and retention of axial chirality in the fluorenyl carbanions1

Abstract: 1-(tert-Butyl- or 1-(p-tolyl-sulfinyl)naphthalene-2-carboxylate esters undergo coupling reactions with fluorenyllithiums substituted at the 1-position, providing 1-(1′-substituted-fluoren-9′-yl)naphthalene-2-carboxylate esters as single rotamers where the naphthalene ester substituent is syn to the fluorene 9-H. The stereoselectivity of the coupling reaction, with respect to asymmetric induction at the fluorene 9-C, varies from 21–95% (ee or de) dependant on the sulfoxide, ester and fluorene substituents, and the reaction temperature. The stereomutation of +ac(R)-1-methyl-9-(2′-methoxymethyl-1′-naphthyl)fluorene 33 into ent-33 was achieved through thermal atropisomerisation of 33 to the –sc(R)-rotamer 34, followed by lithiation of 34 and then reprotonation of the resultant fluorenyllithium 35, demonstrating the retention of axial chirality in the fluorenyl carbanion.

10-Gbit/s error-free transmission of 2-ps pulses over a 45-km span using distributed Raman amplification at 1300 nm

Abstract: Summary form only given. To meet the requirements of upgrading existing optical fiber networks and to considerably extend the potentially useable bandwidth in the low-loss region in optical fibers, broadband, fiber-based amplifiers outside the Er gain window are required. The wavelength flexibility of Raman fiber amplifiers make them very attractive for integration in current and future systems. Here we report the results of 10-Gbit/s, 2-ps transmission at 1300 nm using distributed Raman amplification. Almost no penalty has been observed for the experimental situation where the system loss was directly compensated by the Raman gain and where an excess gain of +8 dB was achieved.

A frequency domain model-order-deduction algorithm for linear systems

Abstract: Physical system modeling, whether automated or manual, requires a systematic procedure to choose the appropriate order of a system model. This can be most readily accomplished by determining the appropriate order of the component submodels. With previous schemes, the primary means to determine the required order of component submodels has been to focus on the eigenvalues of the model, specifically, the behavior of the eigenvalues inside of a circle in the complex plane defining a given spectral radius. In this paper we develop a new algorithm, FD-MODA, that uses changes in a model frequency response as an algorithm-stopping-criterion. The model's frequency response provides a more comprehensive indication of model performance and adequacy than just the eigenvalues, and is more meaningful in the context of frequency-domain controller design methods.

Robust nonlinear control based on describing function methods

Abstract: The robust control problem for nonlinear sys-tems is discussed from the standpoint of the amplitudesensitivity of the nonlinear plant and final control system.Failure to recognize and accommodate this factor may giverise to nonlinear control systems that behave differently forsmall versus large input excitation, or perhaps exhibit limitcycles or instability. Sinusoidal-input describing functions(sidfs) are shown to be effective in dealing with amplitudesensitivity in two areas: modeling (providing plant mod-els that achieve an excellent trade-off between conservatismand robustness) and nonlinear control synthesis. In ad-dition, sidf-based modeling and synthesis approaches arebroadly applicable. Several practical SIDF-based nonlinearcompensator synthesis approaches are presented and illus-trated via application to a position control problem.Keywords: Nonlinear control systems; describingfunctions; frequency-domain modeling; fourier analysis;frequency-domain design; robust control; synthesis meth-ods; pid control; fuzzy logic; position control.

The Second Cambridge Pulsar Survey at 81.5 MHz

Abstract: We have searched the northern sky for pulsars at the low radio frequency of 81.5 MHz, using the 3.6-hectare array at Cambridge, England. The survey covered most of the sky north of declination -20 deg and provided sensitivities of order 200 mJy for pulsars not too close to the galactic plane. A total of 20 pulsars were detected, all of them previously known. The effective post-detection sampling rate was 1.3 kHz, and the sensitivity to low-dispersion millisecond pulsars was sufficient to allow the detection of objects similar to PSR J0437-4715 (period 5.7 ms, dispersion measure 2.6 cm^-3 pc, mean flux density 1 Jy). No such pulsars were found.

Wire-guided surgical stapler for closure of a puncture site in a blood vessel

Abstract: A surgical stapler comprises shaft 6 with a hollow channel running throughout its length. A surgical staple is housed in the distal end of said channel and a push rod system runs along the shaft to advance and deploy the staple. The stapler is brought into position at puncture site 14 over guide wire 1 which has previously been inserted into blood vessel 5 through puncture 14. Correct placement of the stapler is confirmed by advancing tube 2 over guidewire 1 into blood vessel 5 through puncture 14 when backflow of blood will be observed. Following withdrawal of tube 2, the staple is deployed into artery walls 9 and the stapler removed over guidewire 1 which itself is removed when haemostasis is observed.

Measurements of the effect of bending on dispersion in dispersion-compensating fibers

Abstract: Summary form only given. Single-mode fibers with high normal dispersion at 1550 nm are becoming widely used for dispersion compensation in fiber-optic transmission. The chromatic dispersion of this type of fiber having a complex refractive-index profile and high /spl Delta/n is primarily determined by the fiber waveguide properties. It is expected therefore that even small variations of the field distribution of the fundamental mode caused by fiber bending can affect the dispersion. In the present paper, we study this effect in view of its significance to fiber evaluation and packaging, and also the possible impact on the fiber manufacturing.

Real-time Fourier transform infrared spectroscopy study of the kinetics of acid-catalyzed negative-tone resists based on hexamethoxymethylmelamine and phenolic resins

Abstract: The kinetics of the acid-catalyzed reaction in the novolac-based, negative-tone resist SAL 605 (Shipley Co.) and similar formulations were studied with Fourier transform infrared spectroscopy with an in situ hot plate. Real-time measurements of the reaction kinetics were made in a matrix identical to the lithographic conditions and without interference from the development step. The reaction order in the acid concentration was measured to be 1.2±0.15 at 113 °C, and the overall activation energy was measured to be 113±11 kJ/mol for SAL 605. A kinetic model was explored to explain the observed results. The model invoked the general acid catalysis shown in a prior publication [P. M. Dentinger, K. G. Knapp, G. W. Reynolds, J. W. Taylor, T. H. Fedynyshyn, and T. A. Richardson, Proc. SPIE 3331, 568 (1998)], and that the rate constant for the first link of a hexamethoxymethylmelamine (HMMM) was significantly greater than the rate constant for a second link. This model can be simplified to aid in chemically ampli...

Lossless transmission of 2 ps pulses over 45 km of standard fibre at 1.3 [micro sign]m using distributed Raman amplification

Abstract: A 10 GHz, 2 ps pulse stream at 1.3 /spl mu/m is transmitted over a 45 km span of standard telecommunications fibre using distributed Raman amplification pumped with a compact and highly efficient fibre laser. When the pulse source is tuned to the minimum dispersion wavelength of the fibre, lossless, distortionless pulse transmission is demonstrated. By increasing the Raman pump power, a net gain of 8 dB over the span has been achieved, allowing the demonstration of nonlinear pulse compression.