Mechanical, electronic, thermodynamic and vibrational properties of X2MgAl (X = Sc, Ti and Y) from first principles calculations.

Due to growing interest to predict and design new potential Heusler alloys by using theoretical calculations and highly functional software, research on Heusler alloys has taken great attention. From this point of view, this study considers investigation of X2MgAl (X = Sc, Ti and Y) alloys by adopting first principles calculations for the first time. A thorough investigation has been carried out to reveal these alloys' mechanical, electronic, vibrational and thermodynamic properties. It is seen that all alloys have negative formation energies as - 0.278 eV/atom for Sc2MgAl, - 0.058 eV/atom for Ti2MgAl and - 0.304 eV/atom for Y2MgAl which indicates synthesisability and thermodynamic stability. Mechanical stability investigations based on the elastic constants of alloys have revealed that all alloys are mechanically stable. The electronic band structures of alloys demonstrate that X2MgAl (X = Sc, Ti and Y) alloys are metallic since there is no energy gap near the Fermi level. Cauchy's pressures of alloys are found as - 17.791 GPa for Sc2MgAl, 31.404 GPa for Ti2MgAl and - 11.759 GPa for Y2MgAl which displays that Sc2MgAl and Y2MgAl are brittle and Ti2MgAl is ductile. The phonon dispersion curves are calculated along the lines of high symmetry within the first Brillouin region. Phonon frequencies are completely positive in the full Brillouin region, which proves the dynamic stability of the L21 phases of these alloys. Several thermodynamic properties such as Debye entropy, temperature and vibrational free energy are also computed and analysed. Debye entropies of alloys follow Ti2MgAl > Y2MgAl > Sc2MgAl relationship.

Clinical comparision of intravesical hyaluronic acid and hyaluronic acid-chondroitin sulphate therapy for patients with bladder pain syndrome/interstitital cystitis.

INTRODUCTION: Patients with a history of bladder pain syndrome/interstitial cystitis (BPS/IC) and who responded poorly or unsatisfactorily with previous treatment were compared taking intravesical hyaluronic acid (HA) or hyaluronic acid-chondroitin sulphate (HA-CS). METHODS: Patients were treated with intravesical instillation with 50 mL sterile sodium hyalurinic acid (Hyacyst, Syner-Med, Surrey, UK) (n = 32) and sodium hyaluronate 1.6% sodium chondroitin sulphate 2% (Ialuril, Aspire Pharma, UK) (n = 33). Intravesical instillations were performed weekly in first month, every 15 days in the second month and monthly in third and fourth months, for a total of 8 doses. Patients were evaluated using a visual analog pain scale (VAS), interstitial cystitis symptom index (ICSI), interstitial cystitis problem index (ICPI), voiding diary for frequency/nocturia, cystometric bladder capacity and voided volume at the beginning and at 6 months. All patients had a potassium sensitivity test (PST) initially. Wilcoxon and Mann-Whitney U tests were used for statistical analysis. RESULTS: In total, 53 patients met the study criteria. There were 30 patients in the HA-CS group (mean age: 48.47) and 23 patients in the HA group (mean age: 49.61) (p > 0.05). The initial PST was positive in 71.7% patients (38/53) overall with no difference between groups (p > 0.05). Responses for VAS, ICCS, ICPS, 24-hour frequency/nocturia statistically improved in both groups at 6 months. There was no significant difference in symptomatic improvement (p > 0.05). Eight patients had mild adverse events. CONCLUSION: HA and HA/CS instillation can be effective in BPS/IC patients who do not respond to conservative treatment. An important limitation of our study is that the HA dosage of the 2 treatment arms were different. It would be more appropriate with same HA dosage in both groups; however, there was no commercially available glycosaminoglycan (GAG) substance with same HA dosage for single and combination therapy. Large, long-term randomized studies are required to determine if there is a difference between these treatments.

Instillation of Hyaluronic Acid via Electromotive Drug Administration Can Improve the Efficacy of Treatment in Patients With Interstitial Cystitis/Painful Bladder Syndrome: A Randomized Prospective Study.

PURPOSE: In the treatment of interstitial cystitis, intravesical hyaluronic acid application may be suggested as a treatment option. In this randomized prospective study, the authors aimed to identify whether instilling the hyaluronic acid with electromotive drug administration (EMDA) would increase the tissue uptake and improve the efficacy. MATERIALS AND METHODS: The data of 31 patients who had been diagnosed with bladder pain syndrome/interstitial cystitis (BPS/IC) between 2004 and 2005 were examined. The patients were randomized to two groups: patients in group A received hyaluronic acid directly with a catheter and patients in group B received hyaluronic acid with EMDA. The patients were followed for 24 months and the two groups were compared at certain time intervals. The primary end points of the study were visual analogue scale (VAS) score, global response assessment, and micturition frequency in 24 hours. RESULTS: There were 6 males and 25 females. The two groups were similar in baseline parameters. The decrease in VAS score and the micturition frequency in 24 hours were significantly lower with EMDA at months 6 and 12. The difference between the two groups was not significant at months 1 and 24. Also, treatment with EMDA, positive KCl test, and pretreatment voiding frequency >17 were associated with higher response rates. CONCLUSIONS: Hyaluronic acid installation is an effective glycosaminoglycan substitution therapy in patients with BPS/IC. Instillation of hyaluronic acid via EMDA can improve the efficacy of the treatment; however, lack of long-term efficacy is the major problem with this glycosaminoglycan substitution therapy.

Functional Outcomes and Long-term Durability of Artificial Urinary Sphincter Application: Review of 56 Patients With Long-term Follow-up.

PURPOSE: To evaluate the long-term outcomes of artificial urinary sphincter (AUS) implantation and to report the complication rates, including mechanical failure, erosion, and infection. MATERIALS AND METHODS: From June 1990 to May 2011, AUS (AMS 800) implantations were performed in 56 adult males by one surgeon. Various demographic and preoperative variables, surgical variables, and postoperative outcomes, including success and complication rates with a median follow-up of 96 months, were recorded retrospectively. RESULTS: The mean age of the patients at the time of AUS implantation was 61.8 (±14.2) years. During the follow-up period, the total complication rate was 41.1% (23 patients). The incidence of complications was significantly lower during the follow-up period after 48 months (p<0.05). Kaplan-Meier analysis revealed that 5- and 10-year failure-free rates were 50.3% and 45.2%, respectively. CONCLUSIONS: Long-term durability and functional outcomes are achievable for the AMS 800, but there are appreciable complication rates for erosion, mechanical failure, and infection of up to 30%.

A soft computing based approach using modified selection strategy for feature reduction of medical systems.

The systems consisting high input spaces require high processing times and memory usage. Most of the attribute selection algorithms have the problems of input dimensions limits and information storage problems. These problems are eliminated by means of developed feature reduction software using new modified selection mechanism with middle region solution candidates adding. The hybrid system software is constructed for reducing the input attributes of the systems with large number of input variables. The designed software also supports the roulette wheel selection mechanism. Linear order crossover is used as the recombination operator. In the genetic algorithm based soft computing methods, locking to the local solutions is also a problem which is eliminated by using developed software. Faster and effective results are obtained in the test procedures. Twelve input variables of the urological system have been reduced to the reducts (reduced input attributes) with seven, six, and five elements. It can be seen from the obtained results that the developed software with modified selection has the advantages in the fields of memory allocation, execution time, classification accuracy, sensitivity, and specificity values when compared with the other reduction algorithms by using the urological test data.

Diagnosis of bladder outlet obstruction in men with lower urinary tract symptoms: comparison of near infrared spectroscopy algorithm and pressure flow study in a prospective study.

OBJECTIVE: To investigate the efficacy of near infrared spectroscopy (NIRS) and an algorithm on the diagnosis of bladder outlet obstruction in men with lower urinary tract symptoms (LUTS). METHODS: Male patients with LUTS were recruited and underwent uroflowmetry and urodynamic pressure flow study (PFS) with simultaneous transcutaneous NIRS monitoring. Next, the postvoid residual urine volume was measured using ultrasonography. Data analysis first classified each subject as obstructed or unobstructed using the standard pressure flow data and nomogram and compared these results with the NIRS algorithm, which analyzed the pattern of change of the NIRS data plus the measurements of the postvoid residual urine volume and peak flow rate on uroflowmetry. RESULTS: A total of 65 patients were enrolled in the present study. Of these patients, 10 with equivocal PFS findings and 2 with concurrent urinary tract infection were excluded. Of the 53 patients, 29 and 24 were classified as obstructed and unobstructed according to the PFS outcomes, respectively. The International Prostate Symptom Score and uroflowmetry peak flow rate demonstrated significant differences between the obstructed and unobstructed patients. The NIRS algorithm correctly identified 25 patients diagnosed as obstructed (86.2%) and 21 diagnosed as unobstructed (87.5%) according to the PFS findings. CONCLUSION: The NIRS algorithm could be a noninvasive option for the diagnosis of bladder outlet obstruction in men with LUTS, with 86.2% and 87.5% sensitivity and specificity, respectively.

Hydrodilation of the ureteral orifice in children renders ureteroscopic access possible without any further active dilation.

PURPOSE: We review our experience with hydrodilation of the ureteral orifice for ureteroscopic access in children. MATERIALS AND METHODS: We retrospectively reviewed the results of 30 ureteroscopic procedures performed in 26 children who were followed for 6 months. Ureteral access was obtained with the assistance of a hand irrigation pump without any further active dilation in all cases. RESULTS: A total of 26 patients (86.7%) were completely stone-free after 1 procedure. There was no major complication such as ureteral perforation or avulsion. Mild flank pain was observed in 8 cases (26.7%). Predominant symptoms of bladder spasm were observed in 6 cases (20%). At 6-month followup no patient had pyelonephritis or demonstrated hydronephrosis related to ureteral stricture. CONCLUSIONS: Our study shows that hydrodilation of the ureteral orifice in children renders ureteroscopic access possible with no additional active dilation and no associated complications.

Extracorporeal shock wave lithotripsy in children: evaluation of the results considering the need for auxiliary procedures.

OBJECTIVE: To retrospectively evaluate the efficacy of extracorporeal shock wave lithotripsy (ESWL) in children with renal stones, with regard to ability of ureters to transport the fragments, and need for adjunctive procedures. PATIENTS AND METHODS: Between January 2000 and November 2004, 60 children (24 girls and 36 boys) with a total of 72 stones of the upper urinary tract were treated by ESWL using a PCK V5 lithotriptor. Patients with anatomical abnormalities and staghorn stones were excluded from the study. Stone size ranged from 4 to 28 mm. Mean number of shock waves was 1430 (range 600-2000) per ESWL session and mean energy used for stone disintegration was 12 kV (range 6-18). At 24-48 h after ESWL, a plain film or renal ultrasound was obtained to evaluate stone fragmentation. RESULTS: Our stone-free rate after one session of ESWL was 92.8% and 81.2% for patients with stones smaller than 10mm and stones between 10 and 28 mm, respectively. Seven (11.6%) patients developed distal ureteral steinstrasse, and the stone size was 15-20 mm and 20-28 mm in two and five patients, respectively. The steinstrasse completely cleared under meticulous follow-up. No patient needed an adjunctive procedure, such as a double-J stent or nephrostomy tube placement, or ureteroscopic stone manipulation. CONCLUSION: A child's ureter is capable of transporting the fragments after lithotripsy. Interventional procedures should be a last resort. Expectant management is usually adequate even in patients who develop steinstrasse after ESWL.

Serosal lined extramural tunnel (Ghoneim) principle in the creation of a catheterizable channel in bladder augmentation.

PURPOSE: The flap valve mechanism is often the preferred technique for creating a continent catheterizable channel in bladder reconstruction. The umbilicus is usually the preferred site for stomal placement. However, it is not always possible to bring the conduit to the umbilicus when creating the flap valve mechanism at the bladder level. To prevent this problem, we applied the Ghoneim technique to construct the flap valve mechanism during ileal bladder augmentation. MATERIALS AND METHODS: A total of 10 patients (7 boys and 3 girls) 5 to 17 years old underwent ileocystoplasty in combination with an appendiceal Mitrofanoff procedure as a catheterizable channel. The U-shaped ileal segment was anastomosed to the bivalve native bladder, leaving redundant bowel on the right side. The musculomucosal edges of the redundant bowel were sutured together, forming the posterior wall of the tunnel. The appendix was positioned onto the musculomucosal suture line, and the proximal end was anastomosed to the reservoir with an advancement suture. The ileal segment was then imbricated over the appendix by interrupted silk sutures, forming a serosal lined extramural tunnel. The stoma was placed at the depth of the umbilicus. RESULTS: The underlying diagnoses included mylomeningocele (8) and posterior urethral valve (2). Mean followup time was 12.5 months (range 7 to 21). All patients were continent, and there were no stoma related complications such as stenosis or difficult catheterization. CONCLUSIONS: The Ghoneim technique creates an effective continence mechanism and allows the conduit to reach the umbilicus easily.

Snodgrass hypospadias repair with ventral based dartos flap in combination with mucosal collars.

OBJECTIVE: In this study, we report our results of Snodgrass hypospadias repair in conjunction with use of ventral based vascularized dartos flaps. In all repairs, mucosal collars were created and incorporated into the repair to create a more normal appearing circumcised penis, as described by Firlit. PATIENTS AND METHODS: Records of 60 patients with distal or mid-penil hypospadias who underwent standard Snodgrass repair were evaluated. During circumscribing incision mucosal collars were preserved and used to create a normal appearing circumcision line. A ventral based vascular dartos tissue was preserved as a flap and used as a second layer to cover the entire neourethra before glans closure. RESULTS: All repairs were completed in 1 stage. Mean follow-up was 10.5 months (3-37 months). There were 5 (8.3%) cases of fistula and 6 (10%) cases of meatal stenosis. All patients with fistula formation had meatal stenosis. All patients, except for patients with fistula and/or metal stenosis, were voiding a straight stream and have a slit like meatus with cosmetically normal looking circumcised penis. CONCLUSION: Ventral based flaps are easier to harvest and transpose to cover the neourethra. Combining repairs with mucosal collars enhances the cosmetic results and makes the ventral flap harvesting process easier.

Changes in neuropeptide y tissue concentration in the wall of the rat urinary bladder after acute distension.

Neuropeptide Y (NPY) is known to be associated with the adrenergic system. The relationship among the late micturition disorders following acute urinary distension, the adrenergic system and NPY was investigated. A total of 90 rats were included in the study of which 30 acted as the control group. Acute urinary distension was created in 60 rats. The NPY concentration within their bladders was assessed by the use of radioimmunoassay (RIA) at 3 h after distension and subsequently on days 2, 7 and 21, then the third and sixth months. The NPY concentrations assessed in the third and sixth months were compared with the control group in the same age group. By means of the RIA method, a substantial decline of NPY concentration was observed at 2 days after distension, while the concentration started to increase after day 7 (P = 0.003). This increase continued until the twenty first day (P = 0.004). However, a significant decline was maintained when compared to the concentration before distension. In the third and sixth months, a significant decline were observed in the NPY concentration in comparison to the control group (P = 0.004 and P = 0.005, respectively). Early and late micturition disorders experienced after acute urinary distension may be the result of adrenergic denervation which may be related to NPY.

Results of dorsal midline plication in children with penile curvature and hypospadias.

OBJECTIVES: To present our initial results using dorsal midline (12-o'clock position) plication in children with penile curvature and hypospadias. METHODS: Twenty-five children with hypospadias and ventral curvature confirmed after artificial erection underwent dorsal midline plication and hypospadias repair. Ventral curvature was corrected by making a 5 to 10-mm-long vertical incision through the tunica albuginea at the dorsal midline and approximating the outer edges of the incision with a monofilament polydioxanone stitch. RESULTS: One plication suture was needed in 15 patients. In 8 patients with mid-shaft hypospadias and 2 with proximal penile hypospadias, two and three sutures were needed, respectively. In none of the patients was division of the urethral plate needed, except for one with proximal hypospadias. No complications were encountered during a mean follow-up of 9 months (range 5 to 34). CONCLUSIONS: We believe that most cases of penile curvature with hypospadias can be corrected using dorsal midline plication of the tunica albuginea. Although long-term follow-up is necessary after puberty to confirm any erectile or sensory advantage, this approach might be considered whenever plication is to be performed.