Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHAPE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 109 records · Page 6Linked to original sources
PubMed1980

[Late results of shape-improving and shape-preserving mammaplasties: indication and selection of procedure (author's transl)].

Results of shape-improving and shape-preserving operations to a woman's breast and the quality of the operation method cannot be assessed until a number of years later. Subsequent processes entailing alteration in the structure of the skin and subcutaneous tissue, gliding down of gland tissue to Mm. pectoralis, broadening of vertical scars, and complications to the remaining gland tissue may basically vary the results obtained. Late results and view points leading to the selection of procedure will be discussed and compared with those in the literature.

Adult↗
PubMed2002

Quantitative study of the comma-shaped body, S-shaped body and vascularized glomerulus in the second and third human gestational trimesters.

BACKGROUND: The rat developing metanephros has been quantified, but not the human developing kidney. AIMS: To contribute to the knowledge of the human developing kidney by studying the relative growth of the glomerular structures subtypes in the last two gestational trimesters. MATERIAL AND METHODS: The glomerular compartment of 21 human fetal left kidneys was studied. A stereological study determined the volume density (V(V)), the surface density (S(V)), and the numerical density in the plane (N(A)) of the developing glomeruli in the stages of comma-shaped body (C), S-shaped body (S), and vascularized glomerulus. Growth curves used log-transformed data and the allometric model. RESULTS: Reduction of both C and S bodies, and, consequently, a relative growth of the vascularized glomerulus from the second to the third trimesters. The differences between ages were not significant to the S body V(V) and S(V), but there was a significant N(A) reduction from the second to the third trimesters. An age-related reduction of the C body and an intense growth of the vascularized glomerulus were observed in this period. The allometric coefficient b was negative in both C and S bodies and positive in the vascularized glomerulus in the last two gestational trimesters. CONCLUSION: The growth equations and the observed tendencies of these glomerular subtypes in human fetal life could be useful to assess the kidney maturity through invasive or noninvasive investigative methods in the future.

Embryonic and Fetal Development↗
PubMed1998

S-shaped in comparison to L-shaped partial sternotomy for less invasive aortic valve replacement.

OBJECTIVE: Evaluation of less invasive aortic valve replacement to minimize surgical trauma and achieve a better postoperative quality of life. METHODS: Thirty-three patients had aortic valve replacement using a 4-6 cm small incision and partial sternotomy only. Partial sternotomy was performed proximal (16), S-shaped (14) or horizontal (3). Access for cardiopulmonary bypass was via sternotomy (24) or the right femoral vessels (9). Patient age was 58+/-13 years, 21 had aortic stenosis and 12 aortic incompetence. RESULTS: Surgical exposure was sufficient and allowed for uncomplicated AVR in all patients. Mechanical valves (20), conventional bioprostheses (3), stentless bioprostheses (9) or a homograft (1) were implanted. Crossclamp time was not prolonged in comparison to the conventional technique. Intensive care stay and hospital stay were 1 and 10 days, respectively. One patient had to be reoperated for paravalvular leakage, two patients (horizontal sternotomy) had sternal dehiscence. Postoperative pain was low in most patients. CONCLUSION: Less invasive aortic valve replacement is feasible with good functional results. The S-shaped sternotomy approach is advantageous whereas the horizontal sternotomy is no longer performed due to a high rate of instability. This new technique will be further evaluated in comparison to the conventional approach.

Aortic Valve↗
PubMed2006

STM/STS observation of polyoxoanions on HOPG surfaces: the wheel-shaped [Cu20Cl(OH)24(H2O)12(P8W48O184)]25- and the ball-shaped [{Sn(CH3)2(H2O)}24{Sn(CH3)2}12(A-PW9O34)12]36-.

A combination of scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) techniques have been performed on the wheel-shaped [Cu20Cl(OH)24(H2O)12(P8W48O184)]25- and the ball-shaped [{Sn(CH3)2(H2O)}24{Sn(CH3)2}12(A-PW9O34)12]36- deposited on highly oriented pyrolytic graphite surfaces. Small, regular molecule clusters, as well as separated single molecules, were observed. The size of the molecules is in agreement with the data determined by X-ray crystallography. In STS measurements, we found a rather large contrast at the expected location of the Cu metal centers in our molecules, i.e., the location of the individual Cu ions in their organic matrix is directly addressable by STS.

Journal Article↗
PubMed2006

Surfactantless synthesis of multiple shapes of gold nanostructures and their shape-dependent SERS spectroscopy.

A useful method for the synthesis of various gold nanostructures is presented. The results demonstrated that flowerlike nanoparticle arrays, nanowire networks, nanosheets, and nanoflowers were obtained on the solid substrate under different experimental conditions. In addition, surface-enhanced Raman scattering (SERS) spectra of 4-aminothiophenol (4-ATP) on the as-prepared gold nanostructures of various shapes were measured, and their shape-dependent properties were evaluated. The intensity of the SERS signal was the smallest for the gold nanosheets, and the flowerlike nanoparticle arrays gave the strongest SERS signals.

Journal Article↗
PubMed1991

Cell-shape regulation and matrix protein p52 content in phenotypic variants of ras-transformed rat kidney fibroblasts. Functional analysis and biochemical comparison of p52 with proteins implicated in cell-shape determination.

The 52 kDa transformation-sensitive protein p52 was previously identified as a major substrate-associated component of normal rat kidney (NRK) fibroblasts [Higgins & Ryan (1989) Biochem. J. 257, 173-182]. p52 selectively localized to cellular fractions enriched in substrate focal-contact sites and associated ventral undersurface elements. Rapid attachment/spreading of NRK cells on to prepared p52 matrices and inhibition of fibroblast spreading by antibodies to p52 indicated that this protein participates in shape determination or cell-to-substrate adhesion. NRK cells transformed with Kirsten murine sarcoma virus (KiMSV), with a temperature-sensitive mutant (ts-371 KiMSV) and maintained at the permissive temperature, or with the cloned EJrasval.12 oncogene, exhibited down-regulated accumulation of p52 in the ventral undersurface region. Immunochemical, lectin-affinity and electrophoretic analyses indicated that p52 shares considerable sequence similarity with plasminogen-activator inhibitor type-1, which is consistent with its subcellular localization and likely morphoregulatory activity. The marked down-regulation of p52 expression seen in four different ras-mediated transformation systems, its induction prior to butyrate-induced morphological reorganization in KiMSV-transformed cells, and the morphological consequences of exogenously added p52 or p52 antibodies on NRK fibroblasts suggest that this protein probably functions in cell-shape regulation. Abrogation of p52 matrix accumulation typically seen in ras transformants may contribute, therefore, to the aberrant cytoarchitecture characteristic of malignant fibroblasts.

Animals↗
PubMed2005

The shaping effects of three nickel-titanium rotary instruments in simulated S-shaped canals.

The purpose of this study was to compare the shaping effects of three nickel-titanium rotary instruments, ProTaper, K3, and RaCe, with emphasis on canal transportation. Simulated canals with an S-shaped curvature in clear resin blocks were prepared with a torque-control, low-speed engine. Canals were prepared using the crown-down technique to the size of #30. Canal aberrations were assessed by comparing the pre- and postinstrumentation images under a stereomicroscope. ProTaper instruments caused greater widening of canals compared to K3 or RaCe. Furthermore, ProTaper files showed a tendency to ledge or zip formation at the end-point of preparation. These canal aberrations may be caused by ProTaper finishing files, which appear to be less flexible than other files of the same tip-size, because of their greater taper-size. These results suggest that nickel-titanium file systems including less tapered, more flexible instruments, like K3 and RaCe should be used in the apical preparation of canals with a complicated curvature.

Dental Alloys↗
PubMed2003

Effect of external electric field on the bulk and interfacial properties of weakly dipolar fluid in slab-shaped and sphere-shaped systems.

The effect of a uniform electric field on the bulk and interfacial properties of a model dipolar fluid is investigated by using a modified mean-field density functional theory. Particular attention is given to the dependence of the vapor-liquid phase coexistence in a slab-shaped system on the direction of the electric field with respect to the slab surfaces, as well as in the sphere-shaped system on the surrounding dielectric permittivity. For planar vapor-liquid interfaces, the interfacial profiles of the orientation order parameters and components of the dielectric-permittivity tensor are calculated. Analytical expressions for these interfacial profiles and their dependence on the electric field are obtained. When the electric field is normal to the interface we find that the thermodynamic surface tension is lowered compared to that in zero field, and that when the electric field is parallel to the interface the surface tension is enhanced. In contrast, the mechanical surface tension at the equimolar dividing surface is always enhanced by the field regardless of the field direction, and it assumes its highest value when the field is parallel to the interface.

Journal Article↗
PubMed2006

Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 1. Shaping ability in simulated curved canals.

AIM: To compare the shaping ability of Mtwo instruments with K3 and RaCe instruments. Part 1 of this two-part report describes the efficacy of these nickel-titanium instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degree and 35 degree curves in resin blocks were prepared with Mtwo instruments using a single length technique and with K3 and RaCe instruments using a crowndown preparation technique (n = 20 canals in each case). Pre- and post-instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. The data were analysed statistically using ANOVA and Student-Newman-Keuls test. RESULTS: On an average, canals prepared with Mtwo instruments remained better centred compared with those enlarged with K3 or RaCe instruments. Six RaCe instruments, four K3 files and none of the Mtwo instruments fractured during preparation (P > 0.05). In both of the canal types, Mtwo was significantly faster (P < 0.001). It was possible with all types of instruments to control working length as well. CONCLUSIONS: Mtwo instruments prepared curved canals rapidly, respected original canal curvature well and were safe to use.

Analysis of Variance↗
PubMed1985

Cell shape and division in Escherichia coli: experiments with shape and division mutants.

Double mutants which carry mutations in genes (rodA, pbpA) required for cell elongation (i.e., maintenance of rod shape) in combination with mutations in genes (ftsA, ftsI, ftsQ, or ftsZ) required for septation were constructed. Such mutants were able to grow for about two mass doublings at a normal rate at the restrictive temperature (42 degrees C). The morphology of the cells formed under these conditions was interpreted by assuming the existence of a generalized system for peptidoglycan growth together with two additional systems which modify the shape of the growing peptidoglycan layer. The results also showed that different fts genes probably control different stages in septation. ftsZ (sulB or sfiB) appears to be required for the earliest step in septation, ftsQ and ftsI (pbpB or sep) are required for a later step or steps, and ftsA is required only for the latest stages in septation.

Cell Division↗
PubMed2001

The influence of microcrystalline cellulose grade on shape and shape distributions of pellets produced by extrusion-spheronization.

In this study, five microcrystalline cellulose (MCC) grades were physically characterized and their extrusion-spheronization behaviours were characterized in terms of water requirements and pellet shape profiles. It was found that the MCC grades differed significantly in the physical properties investigated. Physical properties of MCC were found to influence the water requirement for extrusion-spheronization. MCC grades of higher bulk densities, lower porosities and water retentive capacities required less water to produce pellets of equivalent size. These MCC grades were also found to produce pellets of lower sphericity and wider shape distributions. Packing of MCC particles within the agglomerate played a role in determining amount of water retention and pellet rounding during spheronization. However, there was a limit to the influence of packing density on the rate of pellet rounding because poor packing resulted in higher water retentive capacity, which also limited the rate of rounding.

Cellulose↗
PubMed2003

Measurement of body size and shape perception in eating-disordered and control observers using body-shape software.

A disturbance in the perception of personal body size and shape is a key feature of both anorexia and bulimia nervosa, but it has proved difficult to quantify. Previous attempts have used methods like the distorting video technique (DVT), which alters an image by stretching the figure in either the X- or Y-axis. This is a poor representation of the way fat is added to or lost from the body, and the pattern of distortion provides a host of cues to the degree to which the image has been altered. To overcome these problems we have used a specially designed software system that uses biometric data based on real body shapes, instead of simply stretching or compressing images of bodies. This technique also allows individual body parts to be altered separately, so we can determine whether a specific body part is overestimated relative to others. We can also calculate the apparent body mass index (BMI) of our modified pictures, using the perimeter-area ratio (PAR). This allows us to compare an observer's actual BMI with that calculated for their estimated and ideal bodies. We tested 30 anorexic, 30 bulimic and 137 control observers. Our results show that all three observer groups tend to overestimate their body size, but not significantly so. Both the control and bulimic observers prefer an ideal body with a BMI of 20, which is at the lower end of the 'normal' BMI range. However, the anorexics ideal BMI is 15, which is on the border between the emaciated and underweight BMI categories.

Adult↗
PubMed2002

Can simple particle shapes be used to model scalar optical properties of an ensemble of wavelength-sized particles with complex shapes?

We compute the scalar optical properties of size-shape distributions of wavelength-sized randomly oriented homogeneous particles with different nonaxially symmetric geometries and investigate how well they can be modeled with a simple spherical, spheroidal, or cylindrical particle model. We find that a spherical particle model can be used to determine the extinction and scattering cross sections, the single-scattering albedo, and the asymmetry parameter with an error of less than 2%, whereas the extinction-to-backscatter ratio Reb is reproduced only with an error of 9%. The cylindrical and spheroidal particle models yield slightly improved results for Reb that deviate from those obtained for the complex particle ensemble by 7% and 5%, respectively. Large discrepancies between results of the different models are observed for the linear depolarization ratio, thus indicating limitations of models based on simple particle shapes.

Models, Theoretical↗
PubMed1998

U-shaped and J-shaped relationships between serum insulin and coronary heart disease in the general population. The Bruneck Study.

OBJECTIVE: To evaluate the relationship existing between serum insulin and coronary heart disease (CHD) in the general population. RESEARCH DESIGN AND METHODS: In a cross-sectional survey on atherosclerosis and its risk factors, 500 men and 500 women aged 40-79 years were randomly selected from the population of Bruneck, Italy. Clinical, biochemical, and behavioral risk factors of atherosclerosis were assessed in the 936 subjects who participated in the study. Serum insulin was measured at fasting (n = 888) and 2 h (n = 811, known diabetic subjects were excluded) after an oral glucose load. CHD was ascertained by an abnormal electrocardiogram and/or a history of angina or myocardial infarction. RESULTS: Subjects were stratified according to serum insulin quintiles at fasting or 2 h after glucose loading. After adjustment for sex, age, BMI, smoking, physical activity, alcohol intake, and socioeconomic status (analysis of covariance), cardiovascular risk factors clustered in subjects of the top insulin quintile. Multiple logistic regression analysis, including sex and age in model 1, sex, age, BMI, glucose tolerance, socioeconomic status, and behavioral variables in model 2, or this set of variables together with triglycerides and apoproteins A1 and B, fibrinogen, and blood pressure status in model 3, revealed a significant association between high serum insulin and CHD when median insulin quintile was used as the reference class. Moreover, low serum insulin levels, such as those found in subjects of the lowest quintile, were independently related to CHD. These results were found either before (model 1) or after (models 2 and 3) adjusting for several covariates. Consistent results were found in men and women, as well as in younger and older subjects. CONCLUSIONS: Results of the present study suggest that both hyperinsulinemia and "hypoinsulinemia" are independent indicators of CHD. Furthermore, it is proposed that the relationship between CHD and fasting insulin is U-shaped, whereas that between CHD and postglucose insulin may be J-shaped.

Adult↗
PubMed2004

Body shape ideals and perceptions of body shape in Spanish and American college students.

108 Spanish university students (55 men, 53 women) from the University of Barcelona and 111 American college students (51 men, 60 women) from a midwestern liberal arts college responded to Fallon and Rozin's 1985 figure drawings used to measure perceptions of body image. All students were between the ages of 18 and 24 years. Women viewed themselves as being significantly larger than men perceived themselves to be, and women also desired a significantly thinner body for themselves than did men. Overall, men were more satisfied with their body shapes and were more accurate than women in guessing what the other sex would perceive as most attractive. The minimal differences between Spanish and American students suggested that sex has a more powerful influence on perceptions of body shape than does cultural background.

Adolescent↗
PubMed2001

The shape of things to come: regulation of shape changes in endoplasmic reticulum.

Shape changes in the endoplasmic reticulum control fundamental cell processes including nuclear envelope assembly in mitotic cells, calcium homeostasis in cytoplasmic domains of secreting and motile cells, and membrane traffic in the early secretion apparatus between the endoplasmic reticulum and Golgi. Opposing forces of assembly (membrane fusion) and disassembly (membrane fragmentation) ultimately determine the size and shape of this organelle. This review examines some of the regulatory mechanisms involved in these processes and how they occur at specific sites or subcompartments of the endoplasmic reticulum.

Animals↗
PubMedDate not supplied

[Shape conservatism and shaping variability. The comparative analysis of Hydrozoa and Scyphozoa early development].

The morphogenetic pathways based on the self-organization take an important part in the early development of White Sea Cnidarians--Dynamena pumila (Hydrozoa) and Aurelia aurita (Scyphozoa). Comparative analysis of their early development revealed two patterns of embryonic spatial structure reproduced in the morphogenesis of both species in spite of the differences of morphogenetic paths. These are toroidal and bilaterally symmetrical shapes. It is possible that these shapes correspond to the equilibrium states of developing system and their stable reproduction is a result of epigenetic rather than genetic program.

Animals↗
PubMed1995

Cell shape and chromosome partition in prokaryotes or, why E. coli is rod-shaped and haploid.

In the rod-shaped cells of E. coli, chromosome segregation takes place immediately after replication has been completed. A septum then forms between the two sister chromosomes. In the absence of certain membrane proteins, cells grow instead as large, multichromosomal spheres that divide successively in planes that are at right angles to one another. Although multichromosomal, the spherical cells cannot be maintained as heterozygotes. These observations imply that, in these mutants, each individual chromosome gives rise to a separate clone of descendant cells. This suggests a model in which sites for cell division form between pairs of sister chromosomes at the time of segregation, but are not used in spherical cells until further rounds of replication have taken place, thus ensuring clonal ('hierarchical') segregation of chromosomes into progeny cells. The role of the morphogenetic membrane proteins is to convert the basically spherical cell into a cylinder that is able to divide as soon as replication and segregation have been completed, and thus to maximise the number of viable cells per genome.

Bacterial Proteins↗