Double longitudinal myotomy in gender-affirming colovaginoplasty: an innovative surgical technique to prevent and treat neovaginal spasms.

BACKGROUND: Gender-affirming colovaginoplasty (GACv) presents excellent postoperative results. However, neovaginal spasms, reported as painful cramps, can affect the sexual life of patients. AIM: The study sought to describe an innovative surgical technique and evaluate its impact on the prevention and treatment of neovaginal spasms. METHODS: This was a single-center prospective observational study with 2 series of patients: (1) patients who underwent GACv with double myotomy (DM) for spasm prevention (series A), in which longitudinal myotomies were performed across the defunctionalized colon, transecting the taenias, and resecting 2 strips of the intestinal muscle layer of approximately 1- to 2-mm wide and tall, leaving intact colonic tissue between strips; and (2) patients who reported neovaginal spasms in whom intravaginal-DM was performed as treatment surgery (series B), in which the posterior wall of the neovagina was dissected from the rectum and transected by longitudinal myotomies, resecting 2 strips of endoluminal mucosa and submucosal muscle of approximately 1- to 2-mm wide and tall, and the colonic mucosa was subsequently closed. OUTCOMES: Patient-reported outcomes and neovaginal examination were performed following standardized protocols. RESULTS: In series A, 177 patients underwent GACv with the DM technique and were prospectively followed for a median time of 18 months (interquartile range, 13-60 months). No patients reported neovaginal spasms. In series B, 18 patients who reported neovaginal spasms after GACv were treated with intravaginal DM. After a median time of 35 months (interquartile range, 26-45 months), 83% (n = 15 of 18) reported remission of symptoms. CLINICAL IMPLICATIONS: Double longitudinal myotomy performed on the derived portion of the colon in colovaginoplasty is an easy-to-perform and safe technique that may prevent and treat postoperative neovaginal spasms. STRENGTHS AND LIMITATIONS: Our results presented certain limitations, mainly associated with a low prevalence of neovaginal spasms, which, being of personal perception, can be underdiagnosed. To the same extent, the fact that it is a monocentric experience limits the possibility of extrapolating it to other centers. Moreover, a more trained surgical team may be the cause of fewer postoperative complications. On the other hand, the fact of being a reference center for gender-affirming surgery, having our procedures protocolized, and the prospective nature of the study allowed us to obtain a certain homogeneity and granularity of the results. CONCLUSION: DM is a safe procedure and appears to be highly effective for the prevention and treatment of neovaginal spasms after GACv. Routine use of this technique does not increase the operating time or postoperative complications. Multicenter, prospective studies are required to validate our results.

Sustainable Low-Cost Phosphorus Recovery Using Nanostructured Materials with Reusability Potential.

A new low-cost material with a polymeric base formed from sodium silicate was developed. The material presents a nanostructured, highly rich iron surface with a large phosphorus retention capacity and potential reuse as a crop fertilizer. In the present study, we demonstrate that iron is the element that acts as an adsorbent for phosphate, while the polymeric base functions exclusively as a support for iron. The iron is uniformly adsorbed on the surface of the material, forming nanostructures, which ensure that iron works similarly to nanoparticles in solution but avoid other problems, such as particle agglomeration or the difficulty of separating them after the removal process. Materials were characterised by SEM, EDS, N2 sorption, and image processing, and the effect of pH, ionic strength, and temperature was studied. Sorption kinetics were analysed using Boyd's diffusion model, and adsorption equilibria were studied using several adsorption models. A maximum iron adsorption on the polymeric base of 23.9 ± 0.3 mg Fe∙g-1 was found, while maximum phosphorus adsorption was 366 ± 21 mg P∙g-1 Fe. Thus, phosphorus is recovered from the aqueous medium with an inexpensive material that has the potential to be used directly as a fertilizer.

Cosmetic Revision Surgeries after Transfeminine Vaginoplasty.

BACKGROUND: Vaginoplasty is the most frequent genital gender-affirming surgery. Although both functional and aesthetic outcomes after transfeminine vaginoplasty have improved over the years, cosmetic revision surgeries demand after transfeminine vaginoplasty appears to be increasing and requires updated knowledge. METHODS: All patients who underwent vulvar cosmetic revision surgeries at our institution following transfeminine vaginoplasty from January 2014 to April  2022 were studied. The prevalence, topography and surgical techniques of cosmetic revision surgeries after transfeminine genital gender-affirming surgery were examined using clinical charts review and statistical analysis. RESULTS: During the study period, 354 patients underwent gender-affirming vaginoplasty at our single institution (212 penile inversion vaginoplasty, 122 colovaginoplasty and 20 penile inversion vaginoplasty with scrotal skin graft patients). Forty out of these 354 patients (11.29%) required cosmetic revision surgery after transfeminine vaginoplasty; additionally, 44 patients with vaginoplasty performed at other centres also underwent vulvar cosmetic revision surgery at our clinic during the study period. From all performed cosmetic revision surgeries, most of them (31.42%) were labia corrections, followed by clitoris (23.26%) repair surgeries. Mons Venus (10.20%), urethral meatus (9.38%), spongiosus tissue remnants (8.57%) and introitus (6.53%) revisions followed in frequency. Corrections of peri-inguinal scars (5.30%), anterior commissure (2.84%) and inferior fourchette (2.42%) were less prevalent. No differences were found among the different studied vaginoplasty techniques regarding cosmetic revision surgery prevalence or topography following transfeminine vaginoplasty (p < 0.05). CONCLUSIONS: Cosmetic revision surgeries after transfeminine vaginoplasty are frequent. In our large and long-term cohort study, labiaplasty followed by clitoroplasty were found as the most required cosmetic revision surgical procedures. Further multicentre, prospective and controlled studies are necessary to improve cosmetic outcomes and scientific evidence after transfeminine vaginoplasty. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Towards the Development of Sustainable Hybrid Materials to Achieve High Cr(VI) Removals in a One-Pot Process.

Rising manufacturing costs resulting from the current global situation make it necessary to economize at all stages of production, including waste management. Cost-effective materials that reduce the release of pollutants into the environment are becoming mandatory. In this work, a sodium silicate polymeric material, functionalized with iron, was synthesized. The material contains iron-rich nanostructures on the surface, which are responsible for the decontamination process. The inorganic material was further treated with a reducing eucalyptus extract to improve its decontamination performance. Both the inorganic and hybrid materials were used for decontamination of Cr(VI), a widely emitted chemical waste product. The hybrid material provided the best results (1.7 g Cr(VI)·g-1 Fe) in a one-pot process combining reduction and adsorption. The Langmuir-Freundlich model and a statistical thermodynamics adsorption model, together with removal rates, were used to study the processes. High adsorption energies were found, especially in the adsorption of Fe(II) on the polymeric base (33.2 kJ∙mol-1). All materials were characterized using SEM, EDS and N2 sorption, TGA, and IR analyses. In conclusion, the hybrid material synthesized in this study is cheap and easy to produce through environmentally friendly synthesis, and it is a promising adsorbent for the prevention of pollution issues in effluent discharges.

A one-dimensional parameter-free model for carcinogenesis in gene expression space.

A small portion of a tissue defines a microstate in gene expression space. Mutations, epigenetic events or external factors cause microstate displacements which are modeled by combining small independent gene expression variations and large Levy jumps, resulting from the collective variations of a set of genes. The risk of cancer in a tissue is estimated as the microstate probability to transit from the normal to the tumor region in gene expression space. The formula coming from the contribution of large Levy jumps seems to provide a qualitatively correct description of the lifetime risk of cancer in 8 tissues, and reveals an interesting connection between the risk and the way the tissue is protected against infections.

Antioxidant Capacity Assessment of Plant Extracts for Green Synthesis of Nanoparticles.

In this work, water extracts from different bio-based products of plant origin were studied to evaluate their antioxidant capacity and their potential to form metal nanoparticles from aqueous solutions. Two traditional tests, the Folin-Ciocalteu assay and the DPPH radical scavenging capacity method were compared with a more recent one, SNPAC, based on the formation of silver nanoparticles. The silver nanoparticle antioxidant capacity method (SNPAC) was optimized for its application in the characterization of the extracts selected in this work; kinetic studies and extract concentration were also evaluated. The extracts were obtained from leaves of oak, eucalyptus, green tea, white and common thyme, white cedar, mint, rosemary, bay, lemon, and the seaweed Sargassum muticum. The results demonstrate that any of these three methods can be used as a quick test to identify an extract to be employed for nanoparticle formation. Additionally, we studied the synthesis of Cu, Fe, Pb, Ni, and Ag nanoparticles using eucalyptus extracts demonstrating the efficiency of this plant extract to form metallic nanoparticles from aqueous metal salt solutions. Metal nanoparticles were characterized by transmission electron microscopy and dynamic light scattering techniques.

Experimental evidences for a new model in the description of the adsorption-coupled reduction of Cr(VI) by protonated banana skin.

This work reports experimental evidences, not previously considered, to evaluate the Cr(VI) removal by protonated banana skin biomass. Variations in the number of hydroxyl groups, quantified by potentiometric titrations, and CO2 evolution during experiments, were attributed mainly to the oxidation of hydroxylic entities present in the studied material. The results indicate that these groups together with the carboxylic moieties are the main functionalities involved on the adsorption-coupled reduction process. The column experiment carried out provides a new approach to obtain the maximum reduction capacity of the material (3.72 mmol g(-1)). Moreover, we hereby propose a model that reports the first evidence for the instant bound of Cr(III) species to the material used, formed after the reduction of Cr(VI) present in solution. The removal process was quantified carrying out experiments under various pHs, biomass doses and Cr(VI) concentrations, and the mechanism underlying chromium removal was identified.

A physicochemical study of Al(+3) interactions with edible seaweed biomass in acidic waters.

UNLABELLED: In this article, a study of the Al(+3) interactions in acidic waters with biomass of different edible seaweeds: brown (Fucus vesiculosus, Saccorhiza polyschides), red (Mastocarpus stellatus, Gelidium sesquipedale, Chondrus crispus), and green (Ulva rigida, Codium tomentosum), has been performed. The influence of both, the initial concentration of metal and the solution pH, on the Al-uptake capacity of the biomass has been analyzed. From preliminary tests, species Fucus vesiculosus and Gelidium sesquipedale have been selected for a more exhaustive analysis. Sorption kinetic studies demonstrated that 60 min are enough to reach equilibrium. The intraparticle diffusion model has been used to describe kinetic data. Equilibrium studies have been carried out at pH values of 1, 2.5, and 4. Langmuir isotherms showed that the best uptake values, obtained at pH 4, were 33 mg/g for F. vesiculosus and 9.2 mg/g for G. sesquipedale. These edible seaweeds have been found particularly effective in binding aluminum metal ions for most of the conditions tested. Physicochemical data reported at these low pH values could be of interest, not only in modeling aluminum-containing antacids-food pharmacokinetic processes produced in the stomach (pH values 1 to 3) but in remediation studies in acidic waters. PRACTICAL APPLICATION: Aluminum is thought to be linked to neurological disruptions such as Alzheimer's disease. In this article, the adsorption ability of different types of edible seaweeds toward aluminum has been studied. The choice of low pH values is due to the fact that stomach region is acidic with a pH value between 1 and 3 as a consequence of hydrochloric secretion; so physicochemical data reported in this study could be of interest in modeling drug-food interactions, in particular those referring to aluminum-containing antacids-food pharmacokinetic processes produced in the gastrointestinal tract.

Adsorptive behaviour of mercury on algal biomass: competition with divalent cations and organic compounds.

Biosorption processes constitute an effective technique for mercury elimination. Sorption properties of native and acid-treated Sargassum muticum have been studied. Effect of pH, initial mercury concentration and contact time studies provided fundamental information about the sorption process. This information was used as the reference values to analyse mercury sorption under competition conditions. Saline effect has shown little influence in sorption, when only electrostatic modifications took place upon salt addition. On the contrary, if mercury speciation dramatically changed owing to the addition of an electrolyte, such as in the case of chloride salt, very large modifications in mercury sorption were observed. Competition with other divalent cations or organic compounds has shown little or none effect on mercury, indicating that a different mechanism is taking place during the removal of these pollutants. Finally, continuous flow experiments have clearly shown that a reduction process is also taking place during mercury removal. This fact is not obvious to elucidate under batch sorption experiments. Scanning Electron Microscopy analysis of the surface of the materials show deposits of mercury(I) and metallic mercury which is indicative of the reduction process proposed.

Full description of copper uptake by algal biomass combining an equilibrium NICA model with a kinetic intraparticle diffusion driving force approach.

In this work kinetic and equilibrium studies related to copper binding to the protonated macroalga Sargassum muticum are reported. An intraparticle-diffusion linear driving force (LDF) model has been chosen for the quantitative description of the kinetics at several initial metal concentrations. Copper intraparticle homogeneous diffusion coefficient (D(h)) obtained is in the range 0.2-0.9×10(-10) m(2) s(-1). NICA isotherm is demonstrated to constitute a substantial improvement with respect to a simpler Langmuir competitive equation. The binding parameters were chosen to provide the best simultaneous description of the equilibrium experiments. Values of log K(Cu) (4.3), n(Cu) (1) and p (0.31) in NICA isotherm, and log K(Cu) (3.5-5) in Langmuir competitive model, have been obtained. These parameters have been also used to predict the competition between copper and cadmium for binding sites. Two acids, HNO(3) and HCl, have been tested to evaluate their effectiveness to release copper from the metal-laden biomass.

A dynamic proof of mercury elimination from solution through a combined sorption-reduction process.

Physico-chemical factors affecting mercury elimination from solution using fern as sorbent have been analysed. It was demonstrated that interaction of mercury with this biomass follows two processes, adsorption by the functional groups in the biopolymers of the cell wall and reduction by easily oxidized compounds of the biomass. Batch experiments have been done to analyse the effect of pH, ionic strength of the media or competition with other metals. Ionic strength did not show a significant influence in the process, but mercury speciation with the formation of negatively charge complexes represented an important drawback in metal elimination. Continuous flow conditions were also analysed since many industrial applications will require them. These studies allowed distinguishing the two processes: mercury sorption was observed but also reduction of this metal occurs. Reduction to mercury (I) and metallic mercury has been confirmed by scanning electron microscopy analysis of the column filling after the continuous flow experiments.

Aluminium removal from wastewater by refused beach cast seaweed. Equilibrium and dynamic studies.

Aluminium removal has been investigated in synthetic and real wastewaters provided by an aluminium surface treatment plant. Marine algae, obtained as beach cast seaweed (a refuse substance) were used as adsorption material. The influence of pH, metal concentration and time for aluminium elimination was studied by use of synthetic solutions. The optimum pH value was 4.0, which provided a maximum adsorption capacity of 22.5 mg g(-1). The adsorption percentage surpassed 80% in less than 30 min of contact time. Real solutions from the industrial unit were fully characterized and tested in two different fixed-bed columns. One column was filled with 27.5 g of dried beach cast seaweed. Three cycles of adsorption and two of desorption were carried out. The first cycle (12 mg g(-1) maximum sorption capacity) was enough to reach the maximum adsorption capacity at 15 mL min(-1) flow rate. The second column was packed with 1100 g of seaweed and its behaviour was compared to another column filled with activated charcoal, following both the same experimental procedure. Maximum sorption capacity was 14 mg g(-1) for seaweed, whereas the activated charcoal only reached 1.6 mg g(-1) (flow rate of 250 mL min(-1)).

Physicochemical characterisation of the ubiquitous bracken fern as useful biomaterial for preconcentration of heavy metals.

Batch experiments with dry bracken fern have been done to determine cadmium and lead sequestering capacity of this biomaterial. Biomass characterisation was done by infrared spectroscopy and potentiometric analysis. The effect of pH of the metal containing solution, contact time and initial metal concentration has been studied, together with the acid-base properties of the biomaterial. Results obtained have been analysed using mathematical and modelling techniques. Effect of pH on metal sequestration has been correlated with observed acid-base properties of the natural substrate. Kinetic data analysis provided relevant information about metal sequestration rate, showing important differences between lead and cadmium. Maximum uptake was found to be the same for both metals 0.410 mmol/g. This value was also clearly correlated to the number of acidic groups determined for this material which was found to be 0.432 mmol of acidic groups per gram of fern. Results obtained indicate that acidic groups are the functional groups responsible of the sequestration of metal ions and that bracken fern is a promising material for metal preconcentration.

Removal of inorganic mercury from aqueous solutions by biomass of the marine macroalga Cystoseira baccata.

The ability of Cystoseira baccata algal biomass to remove Hg(II) from aqueous solutions is investigated. The mercury biosorption process is studied through batch experiments at 25 degrees C with regard to the influence of contact time, initial mercury concentration, solution pH, salinity and presence of several divalent cations. The acid-base properties of the alga are also studied, since they are related to the affinity for heavy metals. The studies of the pH effect on the metal uptake evidence a sharp increasing sorption up to a pH value around 7.0, which can be ascribed to changes both in the inorganic Hg(II) speciation and in the dissociation state of the acid algal sites. The sorption isotherms at constant pH show uptake values as high as 178 mg g(-1) (at pH 4.5) and 329 mg g(-1) (at pH 6.0). The studies of the salinity influence on the Hg(II) sorption capacity of the alga exhibit two opposite effects depending on the electrolyte added; an increase in concentration of nitrate salts (NaNO3, KNO3) slightly enhances the metal uptake, on the contrary, the addition of NaCl salt leads to a drop in the sorption. The addition of different divalent cations to the mercury solution, namely Ca2+, Mg2+, Zn2+, Cd2+, Pb2+ and Cu2+, reveals that their effect on the uptake process is negligible. Finally, the equilibrium sorption results are compared with predictions obtained from the application of a simple competitive chemical model, which involves a discrete proton binding constant and three additional constants for the binding of the main neutral inorganic Hg(II) complexes, Hg(Cl)2, HgOHCl and Hg(OH)2, to the algal surface sites.

Acid-base properties of brown seaweed biomass considered as a Donnan gel. A model reflecting electrostatic effects and chemical heterogeneity.

Brown seaweeds are interesting materials to be used as biosorbents for heavy metals due to their high binding ability and low cost. The study of the passive biosorption of protons on this kind of materials and its dependency on pH, ionic strength, and medium composition is essential for the practical application of brown algae in wastewater treatment. This work reports the results of the study of the proton binding equilibria of dead biomass from the seaweeds Sargassum muticum, Cystoseira baccata, and Saccorhiza polyschides by potentiometric titration with a glass electrode in the pH range between 2 and 8. Two different salts, NaCl and KNO3, in concentrations ranging from 0.05 to 2 mol x L(-1), were used as background electrolytes. The influence of the ionic strength was accounted for by means of the Donnan model in combination with the master curve approach. Different empirical expressions to describe the swelling behavior of the biosorbent were tested. On the basis of the intrinsic affinity distribution analysis a unimodal Langmuir-Freundlich isotherm was selected to describe the proton binding properties. The results show very little influence of the type of salt. The ionic strength dependency of the proton binding is very similar for the three species, and average empirical expressions of the Donnan volume are proposed. The maximum proton binding capacities obtained ranged between 2.4 and 2.9 mol x kg(-1), with average intrinsic proton affinity constants between 3.1 and 3.3, and heterogeneity parameters of ca. 0.5 for S. muticum and C. baccata, and slightly higher (ca. 0.7) for S. polyschides. The combined Langmuir-Freundlich equation and Donnan model allowed a good description of the experimental charge vs pH curves obtained.

Acid-base equilibria of phthalic acid in saline media: ion association from Pitzer equations.

The protonation constants of 1,2-benzenedicarboxylic acid (phthalic acid) at 25 degrees C in NaCl and CaCl(2) (ionic strengths ranging from 0.1 to 2 mol kg(-1)) were determined potentiometrically, and the results were analyzed by means of Pitzer equations. The values of the logarithm of the first and second dissociation constants ranged from 2.730 and 4.948 (in 0.101 mol kg(-1) NaCl) to 2.449 and 3.984 (in 0.624 mol kg(-1) CaCl(2)), respectively. Tabulated interaction parameters for the inorganic species involved along with salting coefficients estimated from literature allowed the calculation of new interaction parameters for the phthalate-Na(+)/Ca(2+) systems. The specific ion interaction model considered seems to account for the influence of the formation of weak complexes of phthalate with calcium ions on the equilibrium constants.