PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “STRING”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed1994

string of pearls encodes Drosophila ribosomal protein S2, has Minute-like characteristics, and is required during oogenesis.

The first allele of string of pearls (sop) was isolated as a recessive female sterile mutant in a P element enhancer trap screen. Oogenesis in homozygous sop females arrests at approximately stage 5. In addition, homozygous flies of both sexes have Minute-like characteristics that include reduced bristles, delayed development and larval lethality. sop maps to 30D/E on chromosome 2L and encodes the Drosophila homolog of eukaryotic ribosomal protein S2. The gene is present in a single copy in the Drosophila genome and the level of mRNA present in mutant animals is reduced. The identification of a mutant allele that blocks development at a mid-stage of oogenesis may indicate that sop has a specific developmental role during oogenesis in addition to its general role in protein synthesis as a component of the small ribosomal subunit.

Alleles↗
PubMed1984

Duodenal string-capsule culture compared with bone-marrow, blood, and rectal-swab cultures for diagnosing typhoid and paratyphoid fever.

The sensitivity of duodenal string-capsule culture (DSCC) was compared to that of bone-marrow-aspirate culture (BMAC), single 3-ml blood culture (BC), and rectal-swab culture (RSC) for isolating Salmonella typhi and Salmonella paratyphi type A from patients with typhoid and paratyphoid fever. In 36 of 154 patients DSCC could not be used, usually because the patient was too ill to swallow the capsule. In the remaining 118 patients DSCC was positive in 57.6%, RSC in 35.6%, BC in 54.2%, and BMAC in 85.6%. The sensitivity of DSCC was improved by an additional 4.7% if subcultured daily for seven days. The DSCC has no advantage over the combination of RSC and BC and is inferior in sensitivity to the BMAC. However, when a BMAC cannot be obtained, the addition of the DSCC to BC and RSC can be expected to improve the isolation rate by greater than 17%, to at least 85%.

Adolescent↗
PubMed2003

Protein fold comparison by the alignment of topological strings.

Using the definitions of protein folds encoded in a text string, a dynamic programming algorithm was devised to compare these and identify their largest common substructure and calculate the distance (in terms of the number of edit operations) that this lay from each structure. This provided a metric on which the folds were clustered into a 'phylogenetic' tree. This construction differs from previous automatic structure clustering algorithms as it has explicit representation of the structures at 'ancestral' branching nodes, even when these have no corresponding known structure. The resulting tree was compared with that compiled by an 'expert' in the field and while there was broad agreement, differences were found that resulted from differing degrees of emphasis being placed on the types of operations that can be used to transform structures. Some concluding speculations on the relationship of such trees to the evolutionary history and folding of the proteins are advanced.

Computational Biology↗
PubMed1998

Eccentric skin resection and purse-string closure for skin reduction with mastectomy for gynecomastia.

Skin redundancy following mastectomy for gynecomastia does not shrink and resolve in a predictable manner. Excess skin can be addressed best with resection at the time of the original operation if the scar can be minimized. Previously described techniques for resection of skin have shortcomings that include unacceptable scars, poor nipple positioning, and bulkiness of redundant, folded dermal tissue. The current technique for grade 2 and some grade 3 gynecomastias is performed with the creation of a 20-mm-diameter nipple-areolar complex based as a cephalad flap and designed eccentrically around the existing nipple. Eccentric skin resection in the vertical and horizontal planes is performed below the areolar flap. Wide access for completion of mastectomy is gained. The wound is then closed with a subcutaneous purse-string suture and inset of the areolar flap so that the scars are confined to the circumareolar area. This allows immediate skin recontouring with minimal skin scar. The patient does not have to endure prolonged anxiety while awaiting skin contracture, and this procedure eliminates the possible need for secondary surgery to resect redundant skin.

Anesthesia, Local↗
PubMed1986

Surgical treatment of Stahl's ear using the periosteal string.

Surgical treatment of Stahl's ear is reported. Lifting of the cymba and bending of the helix by the periosteal string are the main points. This method is simple, and it is easy to adjust the extent of correction. Four patients were operated on by this method, and no complications were encountered. The results are quite satisfactory. In the follow-up periods (16 to 29 months, average 22.5 months), the operated ears retain their corrected forms and bear close resemblances to the opposite ears.

Child↗
PubMed1999

Purse-string suture for nipple projection.

A simple and useful technique for nipple projection is reported. A buried, subcutaneous, purse-string suture is placed through prick holes and, when tied, gives a nipple mound, without the need of skin incisions, flaps, or undermining. This procedure can be applied to inverted, missing, and/or ill-defined nipples.

Humans↗
PubMed2001

String test measurement to assess the effect of spinal deformity correction on spinal canal length.

STUDY DESIGN: Long cassette coronal and lateral radiographs before and after surgical correction were analyzed and string test measurements made by three observers in 55 surgical cases (13 surgical types). OBJECTIVES: The purpose of the study was to assess the effect of various corrective maneuvers for spinal deformity on the spinal canal length. SUMMARY OF BACKGROUND DATA: When perioperative neurologic deficit occurs, the surgeon removes implants because they are displaced into the spinal canal or the canal has been lengthened. It is important to know the effect certain constructs have on canal length because the ability of the spinal cord to adapt to canal lengthening is variable. METHODS: On the coronal radiographs the concave, convex, midvertebral, and adjusted midvertebral line, and on the sagittal radiographs, the anterior and posterior vertebral body lines were measured. The adjusted coronal line was the assumed path of the spinal cord starting at the midportion of the vertebral body at the top and the bottom of the deformity and then in between, hugging the pedicles as closely as possible while staying inside the pedicles. Adjustments for magnification were made. RESULTS: Anterior compression instrumentation without cages (n = 5) consistently shortened the spinal canal (mean delta -6.67 +/- 2.30 mm, P = 0.003), whereas instrumentation with cages (n = 13) lengthened the canal (mean delta 10.54 +/- 7.58 mm, P = 0.0003). Thoracic curves treated by posterior corrective forces (n = 14) demonstrated lengthening of the canal (mean delta 10.14 +/- 5.23 mm, P = 0.0001), large (n = 5) curves (81-140 degrees, mean delta 13.47 +/- 7.05 mm), and medium (n = 7) curves (50-80 degrees, mean delta 8.43 +/- 3.24 mm). CONCLUSIONS: Many deformity correction maneuvers, although they do not directly include application of posterior or anterior distraction forces, do indirectly lengthen the spinal canal.

Decompression, Surgical↗
PubMed2000

Formation of string defects at thinning transitions in smectic-C* free-standing films

The layer thinning transitions in freely suspended smectic-C* films have been investigated. The defect structure formed by stringlike lines was observed just before the thinning transitions. The string defects disappear after the thinning transition and appear again near the temperature of the next thinning transition. These results clearly indicate that thin free-standing films at the thinning transitions are slightly below the melting temperature of the interior layers.

Journal Article↗
PubMed2001

Solution of Kramers' problem for a moderately to heavily damped elastic string.

We obtain the nucleation rate of critical droplets for an elastic string moving in a double-well potential and subject to noise and damping forces. We obtain this rate for a class of potentials that includes both the asymmetric straight phi(4) and the straight phi(6) potentials. The frequencies of small oscillations about the critical droplet are obtained from a Heun equation. We solve the Fokker-Planck equation for the phase-space probability density by projecting onto the eigenfunction basis. We present a comparison with simulations for the case of the asymmetric straight phi(4) potential.

Journal Article↗
PubMed2002

Roughness at the depinning threshold for a long-range elastic string.

In this paper, we compute to high precision the roughness exponent zeta of a long-range elastic string, at the depinning threshold, in a random medium. Our numerical method exploits the analytic structure of the problem ("no-passing" theorem), but avoids direct simulation of the evolution equations. The roughness exponent has recently been studied by simulations, functional renormalization-group calculations, and by experiments (fracture of solids, liquid meniscus in 4He). Our result zeta=0.388 +/- 0.002 is significantly larger than what was stated in previous simulations, which were consistent with a one-loop renormalization-group calculation. Furthermore, the data are incompatible with the experimental results for crack propagation in solids and for a 4He contact line on a rough substrate. This implies that the experiments cannot be described by pure harmonic long-range elasticity in the quasistatic limit.

Journal Article↗
PubMed2002

Formation of vortex loops (strings) in continuous phase transitions.

The formation of vortex loops (global cosmic strings) in an O(2) linear sigma model in three spatial dimensions is analyzed numerically. For over-damped Langevin dynamics we find that defect production is suppressed by an interaction between correlated domains that reduces the effective spatial variation of the phase of the order field. The degree of suppression is sensitive to the quench rate. A detailed description of the numerical methods used to analyze the model is also reported.

Journal Article↗
PubMed2002

String ratchets: ac driven asymmetric kinks.

We simulated numerically the time evolution of a one-kink bearing, damped elastic string sitting on noiseless periodic substrates of two types: (I) asymmetric, time independent, (II) symmetric, periodically deformable. An asymmetric kink subjected to an ac drive is shown to drift steadily with finite average speed independent of its initial kinetic conditions. In the overdamped regime the resulting net kink transport can be attributed to the rectification of the Brownian motion of a pointlike particle with oscillating mass. For intermediate to low damping completely different features show up, due to the finite size of the objects being transported; in particular, the kink current hits a maximum for an optimal value of the damping constant, resonates at the kink internal-mode frequency and, finally, reverses sign within a certain range of the drive parameters.

Journal Article↗
PubMed2003

Survival-extinction phase transition in a bit-string population with mutation.

A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation, and selection, is studied, using mean-field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transition between extinction due to random drift and survival. For weak selection the population attains a neutral regime. The mean-field theory describes the infinite-size limit, while simulations are used to study quasistationary properties.

Algorithms↗
PubMed2004

Quiescent string dominance parameter F and classification of one-dimensional cellular automata.

The classification of rules may be one of the most fundamental targets in the study of cellular automata. In this paper, we propose a method for achieving such a classification, in which a new quiescent string dominance parameter F, which is orthogonal to lambda, is introduced. For N -neighbor and K -state cellular automata, in the region 1/K<lambda<1-1/K, the maximum F corresponds to the class III rules, and its minimum, to the class II or class I rules. Therefore, transition of the pattern class takes place between them without fail. By using lambda and F, the phase diagram of cellular automata is determined in the (lambda, F ) plane for five-neighbor and four-state cellular automata. The phase diagram indicates that along the F axis, class III rules are distributed in a large F region, while class I and class II rules are, in a small F region, and class IV rules are found in the overlapping region of class II and III rules. These distributions are almost independent of lambda. Along the lambda axis, all four pattern classes are found in the region 0.25<lambda<0.75, and no correlation between pattern class and lambda parameter is observed.

Cells↗
PubMed2004

Trapping and steering on lattice strings: Virtual slow waves and directional and nonpropagating excitations.

Using a lattice string model, a number of peculiar excitation situations related to nonpropagating excitations and nonradiating sources are demonstrated. External fields can be used to trap excitations locally but also lead to the ability to steer such excitations dynamically as long as the steering is slower than the field's wave propagation. I present explicit constructions of a number of examples, including temporally limited nonpropagating excitations, directional excitation and virtually slowed propagation. Using these dynamical lattice constructions I demonstrate that neither persistent temporal oscillation nor static localization are necessary for nonpropagating excitations to occur.

Journal Article↗
PubMed2004

Fluctuations of topological disclination lines in nematic liquid crystals: renormalization of the string model.

Using the tensorial Landau-de Gennes theory, we study the fluctuations of a disclination line in a nematic liquid crystal. By analyzing the structure and the spectrum of the eigenmodes of a line of strength +/-1/2 , we reassess the concept of line tension used in the simple string model of the disclination showing that it does not include the complete set of eigenmodes and must be renormalized. In general, the line tension considerably underestimates the thermal amplitude of a disclination and we find that it is only applicable to severely confined disclinations.

Journal Article↗