Zoltan A. Fekete

Harmonic vibrational frequency scaling factors for the new NDDO Hamiltonians: RM1 and PM6

Scaling factors have been derived to obtain fundamental vibrational frequencies with the recently introduced semiempirical molecular orbital methods RM1 and PM6, implemented in MOPAC2007. A least-squares approach is used with a training set comprised of 90 singlet-state molecules and 922 distinct vibrations, extracted from the NIST Computational Chemistry Comparison and Benchmark Database (CCCBDB). Results are presented both for the conventional Scott-Radom type single-factor fitting, and for a multi-factor linear model: Semiempirical Semiglobal Self-consistently Scaled Quantum Mechanical (S4QM). The new NDDO methods in conjunction with the multi-linear fitting are shown to yield improved prediction of vibrational frequencies. To demonstrate the performance of S4QM//PM6 for calculating vibrational spectra, the examples of indene, indazole and four tetrachlorinated p-dibenzodioxins are presented.

In situ photocatalytic reactor with FT-IR analysis for heterogeneous catalytic studies

Abstract A novel reactor cell with in situ IR analysis was designed and tested experimentally in photocatalytic degradation of tetrachloroethene over TiO2 in the presence of air. The system may operate as a batch, pulse and flow reactor with continuous or flash irradiation.

Theoretical characterization of gas-liquid chromatographic stationary phases with quantum chemical descriptors

Quantitative structure-property relationship (QSPR) solvent model has been developed for the McReynolds constants (prototypical solutes) on 36 gas-liquid chromatographic stationary phases. PM6 semiempirical quantum chemical calculations combined with conductor-like screening model (COSMO) has been utilized. From 276 descriptors considered, forward stepwise variable selection, followed by best subset selection, yielded linear regression models containing six purely quantum chemical and two hybrid, topologically based descriptors. Internal (leave-one-out and bootstrap) as well as external validation methods confirmed the predictive power of these structure-driven models across all 10 McReynolds constants, with 40 Kováts-index units overall root-mean-square prediction error estimate.

Quantum chemical characterization of Abraham solvation parameters for gas-liquid chromatographic stationary phases

Quantum chemical based investigation is presented on the Abraham solvation parameters for 23 molecular (non-polymeric) GLC stationary phases. PM6 semiempirical calculations combined with conductor-like screening model (COSMO) have been utilized. Comprehensive search for an optimal model was carried out, based on best subset selection from 86 variables considered. A unified quantitative structure-property relationship model has been developed for all five Abraham parameters reported. The selected set of five structure-driven descriptors was subjected to statistical analyses, and was shown to be useful for stationary phase classification.

Temperature dependence of the Kováts retention index. Convex or concave curves.

The non-linearity in the temperature dependence of the Kováts index, I (the formation of convex or concave curves) was characterized by the second derivative, d2I/dT2. The expression deduced on a purely mathematical-physicochemical basis is d2I/dT2 = [2TDeltaS(CH2)dI/dT-100deltaDeltaCp]/TDeltaG(CH2). The solute-dependent factor for dI/dT, d2I/dT2, and the extreme temperature in the I vs. T relationship is deltaDeltaCp, which is the molar solvation heat capacity difference between the solute and a hypothetical n-alkane which elutes at the same time as the given solute, while the solvent-dependent factors are the solvation entropy and free energy of the methylene unit, DeltaS(CH2) and DeltaG(CH2). Experimentally, convex Ivs.T curves with a minimum are formed when deltaDeltaCp >> 0, while concave ones with a maximum are observed when deltaDeltaCp << 0. In the event of a linear temperature dependence, the former equation can be simplified: dI/dT = 100deltaDeltaCp/2TDeltaS(CH2). The deviation from linearity (higher d2I/dT2) increases with increasing deltaDeltaCp values. The model equations were tested from the dataset published by the Kováts group on C78 (19,24-dioctadecyldotetracontane), POH (18,23-dioctadecyl-1-untetracontenol), PCN (1-cyano-18,23-dioctadecyluntetracontane) and TMO (1,38-dimethoxy-17,22-bis-(16-methoxyhexadecyl)-octatriacontane) and by present measurements on the Innowax phase.

Reduction of glycine particle size by impinging jet crystallization

The parameters of crystallization processes determine the habit and particle size distribution of the products. A narrow particle size distribution and a small average particle size are crucial for the bioavailability of poorly water-soluble pharmacons. Thus, particle size reduction is often required during crystallization processes. Impinging jet crystallization is a method that results in a product with a reduced particle size due to the homogeneous and high degree of supersaturation at the impingement point. In this work, the applicability of the impinging jet technique as a new approach in crystallization was investigated for the antisolvent crystallization of glycine. A factorial design was applied to choose the relevant crystallization factors. The results were analysed by means of a statistical program. The particle size distribution of the crystallized products was investigated with a laser diffraction particle size analyser. The roundness and morphology were determined with the use of a light microscopic image analysis system and a scanning electron microscope. Polymorphism was characterized by differential scanning calorimetry and powder X-ray diffraction. Headspace gas chromatography was utilized to determine the residual solvent content. Impinging jet crystallization proved to reduce the particle size of glycine. The particle size distribution was appropriate, and the average particle size was an order of magnitude smaller (d(0.5)=8-35 μm) than that achieved with conventional crystallization (d(0.5)=82-680 μm). The polymorphic forms of the products were influenced by the solvent ratio. The quantity of residual solvent in the crystallized products was in compliance with the requirements of the International Conference on Harmonization.

Consecutive vesicovaginal fistula for transobturator sling perforations and successful repairs with skin flap

To report a reconstructive technique of large vesicovaginal fistula repairs, which is a rare complication of the most modern anti‐incontinence procedures (tension‐free tapes) using the “oldie but goodie” Lehoczkys island flap.

Hüvelyi hálóműtétek gyakorlata az amerikai korlátozó figyelmeztetés után. Merjem, vagy ne merjem?

Absztrakt: Bevezetes: A kismedencei szervek sullyedesenek (POP) előfordulasi aranya az eletkor előrehaladtaval novekszik, es az idősodő nőpopulacio jelentős tobbseget erinti. Az elmult evtizedben szeles korben elterjedtek a POP rekonstrukcioja celjabol alkalmazott szintetikus transvaginalis halo (TVM)-műtetek. Az Amerikai Egyesult Allamok Elelmiszer-biztonsagi es Gyogyszereszeti Hivatala (FDA) altal 2008-ban, majd 2011-ben kiadott figyelmeztetest kovetően a haloműtetek szamaban drasztikus csokkenes volt megfigyelhető, ugyanakkor mind a mai napig nem erhető el megfelelő hatekonysagu műtet. Celkitűzes: A tanulmany celja a klasszikus, halo nelkuli es halo felhasznalasaval tortenő kismedencei helyreallito műtetek hatekonysaganak osszehasonlitasa volt POP-csokkentő es antiincontinens (anti-SUI-) hatas, valamint intra-, peri- es kesői (36 honap) posztoperativ komplikacios rata alapjan. Modszer: 2013. januar es 2014. januar kozott osszesen 120, II–III. stadiumu, mellső-kozepső kompartmentsullyedesben es genuin s...INTRODUCTION The prevalence of pelvic organ prolapse (POP) with aging is escalating alarmingly, and now becoming a growing epidemic among the elderly. Synthetic transvaginal mesh (TVM) has been employed with increasing popularity in the treatment of POP until the end of the last decade. After the U.S. Drug and Food Administration (FDA) warnings in the years 2008 and 2011, the number of vaginal mesh operations has decreased dramatically. AIM The aim of the study was to evaluate and compare the anti-POP effectivity, the anti-stress incontinence (anti-SUI) efficacy, and the late (36 months) post-operative complications of the anterior vaginoplasty and the TVM operations. METHOD We analysed the clinical data from 120 patients with stage II-III anterior prolapse and concomitant SUI who had undergone surgery at a tertiary referral centre in Hungary between January 2013 and January 2014. Sixty patients underwent Kelly-Stoeckel vaginoplasty and the other 60 cases had TVM operation. The surgical complications were classified using the Clavien-Dindo (CD) classification system. RESULTS The anti-POP (91.6% vs. 63.3%; p<0.001) and the anti-SUI efficacy (90% vs. 55%, p<0.001) were significantly higher in the TVM group than in the vaginoplasty group, while the overall extrusion rate was found 8.3% after a 3-year follow-up. The Clavien-Dindo score (CD) proved that the early post-operative complication profile was similar among the TVM patients as compared to the vaginoplasty group (p = 0.405). CONCLUSION Vaginal mesh surgery represents an effective procedure for prolapse and concomitant SUI with a decreased risk of short- and long-term complications. Orv Hetil. 2018; 159(10): 397-404.

Does anchoring vaginal mesh increase the potential for correcting stress incontinence

BackgroundThis study aims to explore the feasibility of anchoring a four-arm transvaginal mesh (TVM) to the mid-urethra to correct an anterior compartment POP–Quantification stage II–III (Q II–III) and concomitant genuine SUI.MethodsWe analysed clinical data from 248 patients with stage II–III anterior prolapse and concomitant SUI who had undergone surgery at a tertiary referral centre in Hungary between January 2008 and June 2010. One hundred and twenty-four women treated with anterior colporrhaphy and 62 patients implanted with a conventional permanent TVM were selected as historical matched controls. Sixty-two patients received a modified permanent TVM, where the mesh was fixed to the mid-urethra with two stitches for the purpose of potentially correcting SUI. Surgical complications were classified using the Clavien–Dindo (CD) classification system.ResultsThe anti-SUI efficacy was minimally higher in the mTVM group than in the original TVM group (p = 0.44, 96.8% vs 91.9%, respectively), while prosthesis surgery was more effective than anterior colporrhaphy in improving the anterior compartment POP–Q status (96.8, 90.3% vs 64.5%, respectively). Anchoring the mesh did not increase the extrusion rate (p = 0.11). The de novo urge symptoms were not more prevalent among those who had received additional periurethral stitches (p = 1.00, 11.3% vs 12.9%). The incidence of reoperation observed in the mTVM group was non-significantly lower than that in the TVM group (p = 0.15, 6.5% vs 16.1%); however, the difference did not reach the level of significance. The early postoperative complication profile was more favourable among the mTVM patients (classified as CD I: 8.1%; CD II: 1.6%; and CD IIIb: 1.6%) as compared to the TVM group (p = 0.013).ConclusionsThe new, modified mesh surgery represents an effective procedure for prolapse and concomitant SUI with a decreased risk of short- and long-term complications.

Efficacy of anchoring the four-arm transvaginal mesh to the mid-urethra vs original surgery as a surgical correction for stress urine incontinence in coexisting anterior vaginal prolapse grades II and III: study protocol for a randomized controlled trial

BackgroundThe prevalence of obesity with aging is escalating alarmingly; and pelvic organ prolapse (POP) and stress urinary incontinence (SUI) are now becoming a growing epidemic among the elderly. Synthetic transvaginal mesh has been employed with increasing popularity in the treatment of POP and is usually highly effective in controlling the principal symptoms of prolapse. However, studies have reported that mesh operations provide fairly unfavorable SUI cure rates. Therefore, additional anti-incontinence surgical strategies are increasingly being scrutinized to achieve better postoperative continence without any significant side-effects for patients with both POP and SUI. We hypothesize that the modification with the fixing of the mesh to the mid-urethra is superior to the original transvaginal mesh operation (TVM) with regard to anti-incontinence.MethodsOne hundred and thirty patients diagnosed with POP–Q II–III and concomitant SUI requiring surgical treatment will be included in this prospective, randomized, double-blind, controlled clinical trial. Patients will be randomly allocated to receive either original TVM (TVM group, n = 65) or modified TVM surgery (mTVM group, n = 65). As the primary outcome parameter, we will evaluate the objective SUI and POP cure rates. Secondary endpoints include postoperative morbidity as assessed with the International Urogynaecological Association classification and subjective prolapse and incontinence cure rates reported by questionnaires.DiscussionRecognizing the importance of an additional surgical procedure for anti-incontinence management, we aim to investigate whether a stabilizing suturing of the mesh to the mid-urethra delivers superior SUI correction compared to the original prosthesis surgery.Trial registrationClinicalTrials.gov, NCT02935803. Registered on 20 May 2016.