Tubularized incised plate urethroplasty repair in adult hypospadias patients. Are results similar to those reported in the pediatric age group? A prospective study

AbstractObjectiveMost studies published in the literature report on the results of tubularized incised plate urethroplasty (TIPU) for hypospadias repair in children. Hence, the objective of this study was to evaluate the results of TIPU repair in adults.Patients and methodsThe records of 60 adult patients with primary hypospadias treated with TIPU between April 2009 and May 2012 were reviewed. All the procedures were done by the same surgeon under similar conditions and using the same kind of instruments and suture material. On clinical examination, the meatal location, as well as the presence/absence of chordee and penile torsion was assessed. The quality of the spongiosum and the width of the urethral plate were evaluated intraoperatively. The postoperative complications and results were recorded and the data were analyzed.ResultsThe patients’ age ranged from 16 to 27 years with a mean of 21 years. Out of the 60 cases, 43 (72%) had distal penile, 7 (11%) mid-penile and 10 (17%) proximal hypospadias. Penile torsion was present in 10 (17%) cases with 80% having a torsion ≤45° and 20% having a torsion of 45–90°. Ventral chordee ranging from 30° to 90° was present in 14 (23%) cases. Chordee correction was possible by penile de-gloving in 4 (29%) patients (2 with distal and 2 with mid-penile hypospadias), by further mobilization of the urethral plate with the corpus spongiosum in 3 (21%) and by proximal urethral mobilization in another 6 (42%) patients with proximal hypospadias. One (7%) patient also required tunica albuginea plication. The urethral plate was wide in 22 (37%), average in 26 (43%) and narrow in 12 (20%) patients. Fifty percent of the patients with a narrow urethral plate developed complications, compared to 15% of the patients whose urethral plate had an average width and none of the patients with a wide urethral plate. The spongiosum was well developed in 38 (63%) patients, while in 11 (18%) patients each the spongiosum was moderately and poorly developed. The complication rates were significantly higher (55%) in patients with a poorly developed spongiosum as compared to those with a well-developed spongiosum. The overall complication rate was 17% including fistula in 10% of the patients (2 patients with mid-penile and 4 patients with proximal hypospadias). Meatal stenosis was found in 4 patients with distal hypospadias (7%) who responded well to meatal dilatation. The fistula cases required surgical repair with a success rate of 100%. Mean hospitalization and follow-up were 9 days and 6–24 (median 37) months, respectively.ConclusionsComplications encountered in the present study were urethral fistula and meatal stenosis with a higher incidence in patients with proximal hypospadias than reported in the literature. The important factors for the outcome of TIPU were the severity of hypospadias, the degree of curvature and the development of the spongiosum and urethral plate. Proximal hypospadias with a poor urethral plate and severe curvature in adults is not suitable for TIPU. In such cases, single-stage flap urethroplasty or two-stage buccal mucosal urethroplasty should be considered instead

External Bias Dependent Direct To Indirect Bandgap Transition in Graphene Nanoribbon

In this work, using self-consistent tight-binding calculations, for the first time, we show that a direct to indirect bandgap transition is possible in an armchair graphene nanoribbon by the application of an external bias along the width of the ribbon, opening up the possibility of new device applications. With the help of Dirac equation, we qualitatively explain this bandgap transition using the asymmetry in the spatial distribution of the perturbation potential produced inside the nanoribbon by the external bias. This is followed by the verification of the bandgap trends with a numerical technique using Magnus expansion of matrix exponentials. Finally, we show that the carrier effective masses possess tunable sharp characters in the vicinity of the bandgap transition points.Comment: Accepted for publication in Nano Letter

Intrinsic Limits of Subthreshold Slope in Biased Bilayer Graphene Transistor

In this work, we investigate the intrinsic limits of subthreshold slope in a dual gated bilayer graphene transistor using a coupled self-consistent Poisson-bandstructure solver. We benchmark the solver by matching the bias dependent bandgap results obtained from the solver against published experimental data. We show that the intrinsic bias dependence of the electronic structure and the self-consistent electrostatics limit the subthreshold slope obtained in such a transistor well above the Boltzmann limit of 60mV/decade at room temperature, but much below the results experimentally shown till date, indicating room for technological improvement of bilayer graphene.Comment: 10 pages, 2 figure

A CLEAN-based Method for Deconvolving Interstellar Pulse Broadening from Radio Pulses

Multipath propagation in the interstellar medium distorts radio pulses, an effect predominant for distant pulsars observed at low frequencies. Typically, broadened pulses are analyzed to determine the amount of propagation-induced pulse broadening, but with little interest in determining the undistorted pulse shapes. In this paper we develop and apply a method that recovers both the intrinsic pulse shape and the pulse broadening function that describes the scattering of an impulse. The method resembles the CLEAN algorithm used in synthesis imaging applications, although we search for the best pulse broadening function, and perform a true deconvolution to recover intrinsic pulse structre. As figures of merit to optimize the deconvolution, we use the positivity and symmetry of the deconvolved result along with the mean square residual and the number of points below a given threshold. Our method makes no prior assumptions about the intrinsic pulse shape and can be used for a range of scattering functions for the interstellar medium. It can therefore be applied to a wider variety of measured pulse shapes and degrees of scattering than the previous approaches. We apply the technique to both simulated data and data from Arecibo observations.Comment: 9 pages, 6 figures, Accepted for publication in the Astrophysical Journa

The Index of (White) Noises and their Product Systems

(See detailed abstract in the article.) We single out the correct class of spatial product systems (and the spatial endomorphism semigroups with which the product systems are associated) that allows the most far reaching analogy in their classifiaction when compared with Arveson systems. The main differences are that mere existence of a unit is not it sufficient: The unit must be CENTRAL. And the tensor product under which the index is additive is not available for product systems of Hilbert modules. It must be replaced by a new product that even for Arveson systems need not coincide with the tensor product

Additional Muscle Slip of Bicipital Aponeurosis and its Anomalous Relationship with the Median Cubital Vein

The cubital region of the arm is a common site for recording blood pressure, taking blood for analysis and administering intravenous therapy and blood transfusions. During the routine dissection of a 70-year-old male cadaver at the Kasturba Medical College, Manipal, Karnataka, India, in 2015, it was observed that the aponeurotic insertion of the biceps brachii muscle divided into two slips. The medial slip fused normally with the deep fascia of the forearm, while flexor carpi radialis muscle fibres originated from the lateral slip. There was also a single vein in the forearm, the cephalic vein, which bifurcated to form the median cubital vein and the cephalic vein proper. The median cubital vein, further reinforced by the radial vein, passed deep to the two slips of the bicipital aponeurosis and then continued as the basilic vein. During venepuncture, medical practitioners should be aware of potential cubital fossa variations which could lead to nerve entrapment syndromes

Dynamics of Team Teaching and Research in a Management School: Learning and Imperatives

This paper discusses the experience of team teaching to address the issues of integration of academic inputs by bringing multi-disciplinary perspective together and thereby enhance learning experience of participants. The paper delves on the process, events and outcome of team teaching by four faculty members at IIM Ahmedabad who collaborated in teaching, writing cases, and doing research for a period of more than three years. The experience has been summarized using the following dimensions: need for team-teaching, existing mechanisms and barriers, opportunities and potential, imperatives, fall-outs and challenges experienced in the process. The cohesion, trust and mutual respect are key imperatives. The other factors contributing to the success of team-teaching are strong felt need by the members for integration in programmes, complementary skills and experiences of team members, frequent programmes with integrated components that provided continuous opportunities for learning, co-location of the instructors, and off-site programmes that provided opportunities for close get-togethers. The autonomy granted by the institution to instructors and co-coordinators to design and execute learning opportunities was also instrumental in the success. In an environment where the rule of the game is individualism, forming teams creates fears of loss of importance and recognition. The experience shows that the competency of the members and the overall effectiveness of the tasks are strengthened if the team believes in “reciprocating interdependence”. This can be possible only if members allow themselves opportunities to experiment, improvise and review

Surface recombination measurements on III–V candidate materials for nanostructure light-emitting diodes

Surface recombination is an important characteristic of an optoelectronic material. Although surface recombination is a limiting factor for very small devices it has not been studied intensively. We have investigated surface recombination velocity on the exposed surfaces of the AlGaN, InGaAs, and InGaAlP material systems by using absolute photoluminescence quantum efficiency measurements. Two of these three material systems have low enough surface recombination velocity to be usable in nanoscale photonic crystal light-emitting diodes