Significant Curvature Research Articles

Surgical Correction of Peyronie's Disease via Tunica Albuginea Plication or Partial Plaque Excision with Pericardial Graft: Long Term Follow‐Up: An Editorial Comment

This is an excellent article on two surgical techniques to straighten the penis in Peyronie’s disease. As with other series it is evident that grafting, be it autologous or extracellular matrix grafts, is associated with a significant risk of erectile dysfunction (ED) and a risk of some penile shortening [1,2]. In this article, 32% had worsening erections and 21% new onset of ED after a grafting procedure. There was an objective loss of length in 33% in the grafting group with 22% wishing that they had not had the operation. It is clear, however, that patients who request a grafting technique usually have more severe PD with a more significant curvature and are more concerned about length loss. It is, therefore, not surprising that satisfaction is less than in the plication group. As patients with PD have significant risk factors for “de novo” ED at presentation, there is a significant risk that this may get worse when a grafting technique is performed [3]. The article highlights that in advanced and severe disease it may therefore be better to insert a penile prosthesis that straightens the penis and corrects any ED while minimizing loss of length. Informed consent is therefore imperative so that patients can have real expectations and then hopefully satisfaction improved.

Intrinsic curvature associated with the coordinately regulated anthrax toxin gene promoters

The current model for virulence gene regulation in Bacillus anthracis involves several trans-acting factors, the most important of which appears to be the anthrax toxin activator encoded by the atxA gene. AtxA is a positive regulator of the toxin genes pagA, cya and lef, and of a number of other plasmid- and chromosome-encoded genes. The AtxA protein (56 kDa) possesses a predicted winged-helix DNA-binding domain and phosphotransferase system-regulated domains, but the mechanism for positive regulation of AtxA target genes is not known. Sequence similarities in the promoter regions of AtxA-regulated genes are not apparent, and recombinant AtxA binds DNA with a high affinity in a non-specific manner. We hypothesized that the toxin genes possess common structural features or cis-acting elements that are required for positive regulation. We employed deletion analyses to determine the minimal sequences required for atxA-mediated toxin gene expression. In silico modelling and in vitro experiments using double-stranded DNA corresponding to the toxin gene promoter regions indicated significant curvature associated with these regions. These findings suggest that the structural topology of the DNA plays an important role in the control of anthrax toxin gene expression.

The effect of wafer curvature on x-ray rocking curves from gallium nitride films

The full width at half maximum (FWHM) of x-ray rocking curves is often used as a measure of the crystalline quality of thin films. In this paper, the effects of wafer curvature on the x-ray rocking curves (ω-scans) obtained from a 2in. 0001-oriented sapphire wafer and an epitaxial 0001-oriented GaN film grown on such a wafer are discussed. Beam height reduction can limit curvature-related effects for symmetric and asymmetric reflections; these effects are generally significant for low dislocation density GaN films. Due to the shape of the area illuminated by the x-ray beam in the skew symmetric geometry, beam width reduction is instead appropriate, but this still gives an underestimate of ω-FWHM values obtained with an open detector and an overestimate of ω-FWHM values obtained with an analyzer. Therefore, skew symmetric ω-FWHM values from curved samples are often unreliable. Additionally, Williamson–Hall analysis using ω-scans is rendered unreliable in the presence of significant curvature. Variations in ω-FWHM values for different experimental configurations are attributed to nonspherical wafer curvature, changes in illuminated area for each reflection, and changes in sampled volume at each step in the ω-scan. Although this paper focuses on GaN films, the results are applicable to a wide range of other materials exhibiting wafer curvature.

The primary noise sources associated with turbulent Coanda wall jets

A wide variety of aeronautical and aerospace applications utilize the Coanda effect. However, due to the enhanced turbulence levels observed with devices using this effect, turbulent mixing noise is a primary noise source. For supersonic jets close to Coanda surfaces, shock‐associated noise (both broadband and screech tones) is also a significant source of sound. A theory has been developed to predict the turbulent mixing noise emitted by unit‐volume of jet‐type shear‐layer turbulence close to a rigid plane, and extended to a plane two‐dimensional wall‐jet. However, most flows of practical interest are three‐dimensional and, in the case of the Coanda jets, exhibit significant curvature. This paper extends the previous models for turbulent mixing noise to predict the aeroacoustic characteristics of a three‐dimensional turbulent flow over a Coanda surface. Details of experimental observations of the shock‐cell structure associated with supersonic Coanda wall jets, and a method of modeling the corresponding shock‐associated noise, is also discussed.

FastSize™ Medical Extender for the treatment of Peyronie’s disease

This paper reports on the scientific principles, treatment protocol and initial trial results of the FastSize™ Medical Extender, a new medical device developed for the treatment of Peyronie’s disease and phalloplasty utilizing controlled periodic stretching of the penis; other uses of the device are also mentioned. Initial Institutional Review Boards monitored clinical trials of the device indicate that significant (10–45°) improvement in curvatures are achievable and that larger scale trials are therefore justified. The device appears to meet a previously unmet need within the population of Peyronie’s disease sufferers for a noninvasive, nonsurgical first-option treatment modality. The device works by holding the penis in a cradle and subjecting it to gentle stretching, the tension being provided by small metal extensions that are added to the cradle frame to provide traction against internal springs. Patient education is minimal for the device, but patient compliance with the extended daily treatment procedure is critical for significant curvature change. While a review of appropriate reimbursement codes has not been conducted, the pricing of the device makes it easily affordable. Although it has not yet been formally studied, the device also appears to have applications beyond Peyronie’s disease; such as offering potential for offsetting penile shortening prior to implant surgery, preventing shortening following PD penile reconstruction and after radical prostatectomy where loss of penile length is commonly reported. The recent trial noted that, over a 6-month period, patients reported increases in penile length of 1–2.0 cm, with an accompanying increase in girth. There are no alternative devices available that have proven efficacy as a result of a clinical trial and, given reproducible results, the device will begin to play an important role in treatments that require penile tissue remodeling. Future developments should include larger scale, multicenter trials aimed at reproducing the results of the initial study on Peyronie’s disease, also trials in conjunction with pharmacological treatment involving plaque remodeling agents such as verapamil and interferon, and trials that will investigate the possible benefits of the device for penile enlargement that may help pre- and postsurgical candidates for penile implants and penile reconstruction following prostatectomy.

T05-O-20 Plaque incision surgery with tunica vaginalis patch for penile curvature in La Peyronie's disease: preliminary report

Purpose Peyronie's disease in men with significant penile curvature is often treated with plaque incision/excision and grafting; when erectile dysfunction is associated, a penile prosthesis implantation is mandatory. We present our initial experience of plaque incision surgery with tunica vaginalis patch and concomitant implantation of penile prosthesis in patients with severe curvature due to IPP. Material and methods Nine patients, with severe penile curvature and erectile dysfunction, due to IPP, were considered from January 2006 to October 2007. A circumferential subcoronal and a longitudinal penoscrotal incisions were made. An H-shaped incision was made on the tunica albuginea. The albuginea defect was measured. Through the penoscrotal incision, an adequate tunica vaginalis patch was obtained to restore the defect and it was sutured to the albuginea. Then the penile prosthesis was placed in a standard fashion. Results The mean operative time was 200 + 15 min. In four patients with mild erectile dysfunction a soft penile implant was placed; in five patients with complete erectile dysfunction an inflatable penile prosthesis was positioned. The mean follow up is 13.4 months. We recorded complications in only 1 patient (scrotal hematoma with spontaneous resolution). All patients are able to achieve sexual intercourse. No recurrence of penile curvature have been observed. Only one patient is unsatisfied, due to penile shortening. Conclusions Our experience shows that the plaque incision surgery with tunica vaginalis patch and concomitant implantation of penile prosthesis in patients with severe curvature due to IPP is a safe and efficacious technique, with encouraging satisfaction rate for patients.

Penisraffplastik zur Behandlung schwerer Penisdeviationen

Penile plication procedure was performed on 27 patients (median age 24 years) to correct marked penile deviation (mean deviation angle 50 degrees). On average 4 (2-10) sutures were necessary. Normal intercourse and potency was restored in all. 26 patients were fully satisfied with the result, while in three there were suture problems (fistula, granuloma). There was one recurrence, three weeks postoperatively, in a patient who failed to follow the recommended six-week period of sexual abstinence. But this recurrence was lastingly corrected by a second penile plication procedure. No lasting complications were noted a mean of 48 months postoperatively. This type of operation is the treatment of choice for significant penile curvature.

Monovalent Cation Binding by Curved DNA Molecules Containing Variable Numbers of A-Tracts

Monovalent cation binding by DNA A-tracts, runs of four or more contiguous adenine or thymine residues, has been determined for two curved ∼200 basepair (bp) restriction fragments, one taken from the M13 origin of replication and the other from the VP1 gene of SV40. These two fragments have previously been shown to contain stable, centrally located bends of 44° and 46°, respectively, located within ∼60 bp “curvature modules” containing four or five irregularly spaced A-tracts. Transient electric birefringence measurements of these two fragments, sequence variants containing reduced numbers of A-tracts in the SV40 curvature module or changes in the residues flanking the A-tracts in the M13 curvature module, have been combined with the free solution electrophoretic mobilities of the same fragments using known equations to estimate the effective charge of each fragment. The effective charge is reduced, on average, by one-third charge for each A-tract in the curvature module, suggesting that each A-tract binds a monovalent cation approximately one-third of the time. Monovalent cation binding to two or more A-tracts is required to observe significant curvature of the DNA helix axis.

ISS-flation

Inflation may occur while rolling into the metastable supersymmetry-breaking vacuum of massive supersymmetric QCD. We explore the range of parameters in which slow-roll inflation and long-lived metastable supersymmetry breaking may be simultaneously realized. The end of slow-roll inflation in this context coincides with the spontaneous breaking of a global symmetry, which may give rise to significant curvature perturbations via inhomogenous preheating. Such spontaneous symmetry breaking at the end of inflation may give rise to observable non-gaussianities, distinguishing this scenario from more conventional models of supersymmetric hybrid inflation.

Spacetime Curvature is Important for Cosmology Constrained with Supernova Emissions

We investigate universe expansion models as functions of emission frequency ratio decline rather than redshift z, using the latest on-line, self-consistent data from 192 supernovae. We present results for simpler and some current models of cosmology, including those with dark energy (standard model) and a recent model correcting for the effect of a small time-dependent, emission frequency increase with lookback. This new model, with a gentle lookback decline of the Planck constant, and the standard model fit the data with similar confidence according to Bayesian Information Criteria. The standard model tends towards solutions high in matter density while remaining flat, but models without dark energy tend towards dilute universes with significant spacetime and curvature and a smaller Hubble constant. We conclude the normalized spacetime parameter, Ω k , should not be ignored and it includes the combined contributions of huge spacetime magnitude and curvature.

Handling of impreciseness in gray level corner detection using fuzzy set theoretic approach

Reliable corner detection is an important task in determining shape of different regions in an image. To detect corners in a gray level image under imprecise information, an algorithm based on fuzzy set theoretic model is proposed. The uncertainties arising due to various types of imaging defects such as blurring, illumination change, noise, etc., usually result in missing of significant curvature junctions (corners). Fuzzy set theory based modeling is well known for efficient handling of impreciseness. In order to handle the incompleteness arising due to imperfection of data, it is reasonable to model image properties in fuzzy frame work for reliable decision making. The robustness of the proposed algorithm is compared with well known conventional detectors. The performance is tested on a number of benchmark test images to illustrate the efficiency of the algorithm.

International study of factors affecting human chromosome translocations

Chromosome translocations in peripheral blood lymphocytes of normal, healthy humans increase with age, but the effects of gender, race, and cigarette smoking on background translocation yields have not been examined systematically. Further, the shape of the relationship between age and translocation frequency (TF) has not been definitively determined. We collected existing data from 16 laboratories in North America, Europe, and Asia on TFs measured in peripheral blood lymphocytes by fluorescence in situ hybridization whole chromosome painting among 1933 individuals. In Poisson regression models, age, ranging from newborns (cord blood) to 85 years, was strongly associated with TF and this relationship showed significant upward curvature at older ages versus a linear relationship ( p < 0.001). Ever smokers had significantly higher TFs than non-smokers (rate ratio (RR) = 1.19, 95% confidence interval (CI), 1.09–1.30) and smoking modified the effect of age on TFs with a steeper age-related increase among ever smokers compared to non-smokers ( p < 0.001). TFs did not differ by gender. Interpreting an independent effect of race was difficult owing to laboratory variation. Our study is three times larger than any pooled effort to date, confirming a suspected curvilinear relationship of TF with age. The significant effect of cigarette smoking has not been observed with previous pooled studies of TF in humans. Our data provide stable estimates of background TF by age, gender, race, and smoking status and suggest an acceleration of chromosome damage above age 60 and among those with a history of smoking cigarettes.

Analytical and experimental investigation of small-scale unintended releases of hydrogen

Knowledge of the concentration field and flammability envelope from a small-scale hydrogen leak is an issue of importance for the safe use of hydrogen. A combined experimental and modeling program is being carried out by Sandia National Laboratories to characterize and predict the behavior of small-scale hydrogen releases. In contrast to the previous work performed by Sandia on large, momentum-dominated hydrogen leaks, these studies are focusing on small leaks in the Froude number range where both buoyant and inertial forces are important or, in the limit, where buoyancy dominates leak behavior. In the slow leak regime-buoyant forces affect the trajectory and rate of air entrainment of the hydrogen jet leak and significant curvature can occur in the jet trajectory. Slow leaks may occur from leaky fittings or o-ring seals on hydrogen vehicles or other hydrogen-based systems where large amounts of pressure drop occur across the leak path. Low-pressure electrolyzers or vents on buildings or storage facilities containing hydrogen are also potential sources for slow leaks.The small-scale leak investigation is a combined experimental and modeling program. As part of the modeling effort a fast-running engineering model for the buoyant jet from a hydrogen slow leak was developed. The model computes the trajectory of the buoyant jet and the hydrogen concentration decay along the jet trajectory. Simulation times for the slow-leak engineering model are a few seconds on a computer workstation as compared to many hours for a Navier–Stokes equation simulation of the same leak. As part of the experimental effort, a planar laser-Rayleigh scattering and CCD camera technique were used to measure high-speed images of the concentration field from slow hydrogen leaks. Planar laser-Rayleigh scattering is a laser-based diagnostic technique that is sensitive to gas density and is, hence, well suited to accurately measure the flow behavior of hydrogen exiting a leak into ambient air.Comparisons are made between the measured slow leak concentration fields and predictions from the slow leak engineering model. Calculations from the model and experimental results are presented to explain the behavior of slow leaks over the Froude number range of interest.

Asymptotic analysis of the selective dip coating of power-law fluids

The dip coating of a chemically micropatterned surface bearing alternating wetting and nonwetting vertical strips is analyzed for a non-Newtonian power-law fluid. Asymptotic matching is used to determine the thickness of liquid films deposited on the O(10μm) strips at small capillary and Bond numbers. The chemical patterning that confines the fluid laterally induces a significant transverse curvature of the free-surface. The streamwise variation in this transverse curvature along the strip provides an additional contribution to the capillary pressure gradient that is not present for uniform surfaces. Consequently, the difference in the thickness of the deposited liquid film relative to a Newtonian fluid is significantly less than for homogeneous plates or fibers.

Detection of explosives by Terahertz synthetic aperture imaging—focusing and spectral classification

In the adaptation of Terahertz (THz) synthetic aperture imaging to stand-off screening of concealed weapons and explosives, the incoming THz wavefronts exhibit significant curvature that must be considered in the image reconstruction. Consequently, the imaging array must be focused at a specific distance to correct for the wavefront curvature. In addition to the focusing correction, detection of explosives requires spectral analysis of the reconstructed THz image. Kohonen self-organizing maps are shown to be promising tools for differentiating the spectral signature of C4 explosive from the reflection spectra of metal and semi-transparent barrier materials. To cite this article: A. Sinyukov et al., C. R. Physique 9 (2008).

Determination of the thermodynamics of carbonic anhydrase acid-unfolding by titration calorimetry

The enthalpy of unfolding (Δ uH ) of carbonic anhydrase II was determined by titrating the protein with acid and measuring the heat using isothermal titration calorimetry (ITC) in the temperature range of 5 to 59 °C. By combining the ITC results with our previous findings by differential scanning calorimetry (DSC) in the temperature range of 39 to 72 °C, the Δ uH dependence over a wide temperature range was obtained. The temperature dependence of the enthalpy displays significant curvature indicating that the heat capacity of unfolding (Δ uC p ) is dependent on temperature. The T-derivative of Δ uC p was equal to 100 ± 30 J/(mol × K 2), with the result that the Δ uC p is equal to 15.8 kJ/(mol × K) at 5 °C, 19.0 kJ/(mol × K) at 37 °C and 21.8 kJ/(mol × K) at 64 °C. The enthalpy of unfolding is zero at 17 °C. At lower temperatures, the Δ uH becomes exothermic. This method of determining protein unfolding thermodynamics using acid-ITC, significantly widens the accessible T-range, provides direct estimate of the thermodynamic parameters at physiological temperature, and gives further insight into the third T-derivative of the Gibbs free energy of unfolding.

A search for evidence of strain gradient hardening in Au submicron pillars under uniaxial compression using synchrotron X-ray microdiffraction

When crystalline materials are mechanically deformed in small volumes, higher stresses are needed for plastic flow. This has been called the “smaller is stronger” phenomenon and has been widely observed. Various size-dependent strengthening mechanisms have been proposed to account for such effects, often involving strain gradients. Here we report on a search for strain gradients as a possible source of strength for single-crystal submicron pillars of gold subjected to uniform compression, using a submicron white-beam (Laue) X-ray diffraction technique. We have found, both before and after uniaxial compression, no evidence of either significant lattice curvature or subgrain structure. This is true even after 35% strain and a high flow stress of 300 MPa were achieved during deformation. These observations suggest that plasticity here is not controlled by strain gradients or substructure hardening, but rather by dislocation source starvation, wherein smaller volumes are stronger because fewer sources of dislocations are available.

Transitions between de Sitter minima

We investigate the cosmological signatures of instantons mediating tunneling between de Sitter minima. For generic potentials the Coleman-de Luccia instanton does not necessarily exist; when it does not, the instanton which contributes to the decay rate is the trivial constant solution, known as the Hawking-Moss instanton. With the aid of a toy model we interpret this solution and describe the resulting cosmology. In neither the Coleman-de Luccia nor Hawking-Moss case can the resulting cosmology be closed. An observation of significant positive curvature would therefore rule out the possibility that our universe arose from any transition from a neighboring minimum in the string-theory landscape.

Perception of illuminance flow in the case of anisotropic rough surfaces

Human observers estimate the illumination direction of rough surfaces rather precisely. When surfaces are rough, the illumination generates visible "texture" from differential shading at the level of the roughness, whereas differential illumination at the level of significant global surface curvature leads to the more familiar "shading". The shading is used in conventional shape-from-shading (SFS) algorithms, which ignore the illumination texture cue. Because of this simplification, SFS algorithms are typically formulated as global problems (partial differential equations, etc.). Human observers are likely to apply different methods than do these conventional SFS algorithms, however. When the roughness is not isotropic, one expects systematic errors in the visual detection of illumination direction, conceivably giving rise to erroneous shape estimates. Here we addressed this issue through systematic psychophysics on illumination direction detection as a function of the roughness anisotropy. Our expectations were fully borne out, in that the observers committed the predicted systematic errors. These results are precise enough to allow the inference that illumination direction detection is based on second-order statistics--that is, of edge detector (rather than line detector) activity.

Repeated intratunical injection of adenovirus expressing transforming growth factor‐β1 in a rat induces penile curvature with tunical fibrotic plaque: a useful model for the study of Peyronie’s disease

This study was undertaken to establish a Peyronie's disease model with penile curvature by using recombinant transforming growth factor-beta1 (TGF-beta1) protein or adenovirus (ad-TGF-beta1). Four-month-old male Sprague-Dawley rats were divided into seven groups (n = 18 per group): G1 received a single injection of saline into the tunica albuginea (0.1 mL); G2, repeated injections of ad-LacZ (days 0, 3, and 6; 1 x 10(10) particles/0.1 mL respectively); G3, a single injection of recombinant TGF-beta1 protein (700 ng/0.1 mL); G4, repeated injections of recombinant TGF-beta1 protein (days 0, 3 and 6; 700 ng/0.1 mL respectively); G5, a single injection of low-dose ad-TGF-beta1 (1 x 10(10) particles/0.1 mL); G 6, a single injection of high-dose ad-TGF-beta1 (3 x 10(10) particles/0.1 mL); and G7, repeated injections of low-dose ad-TGF-beta1 (days 0, 3, and 6; 1 x 10(10) particles/0.1 mL respectively). Penile curvature was evaluated 30, 45 and 60 days after treatment, and the penis was then harvested for histological examination. Repeated injection of low-dose ad-TGF-beta1 not only induced fibrous scar in the tunica, which lasted up to 60 days after injection, but also resulted in significant penile curvature by artificial erection test 45 days after treatment. A peculiar histological finding in this group was trapping of inflammatory cells in the tunica, subsequent fibrosis, and formation of cartilage and calcification as well as loss of elastin fibres. This model involving repeated injection of ad-TGF-beta1 may contribute to further investigation of the pathogenesis of Peyronie's disease and the development of new therapeutics targeting this pathway.