Search

• Six Gaussian bands comprise differential absorbance spectra of all examined waters. • Bands A1-A4 in the spectra of chlorinated compounds show dependence of conjugation. • Spectral parameters from long wavelength have high correlation with DBPs formation. This study compared chlorination-induced changes of the properties of natural organic matter (NOM) represented by standard humic substances and NOM present in pristine and anthropogenically-affect reservoirs, rivers, groundwater and seawater. The chlorination-induced changes of NOM properties were quantified using the differential absorbance spectra (DAS) which were processed via numeric deconvolution. Six Gaussian bands were found to comprise the DAS of all examined waters. These bands (denoted as A0, A1, A2, A3, A4 and A5, respectively) have maxima located at ca. 200, 240, 276, 316, 385 and 547 nm. The bands A1-A4 were observed in the DAS of representative model chlorinated compounds. Quantum chemical (QC) calculations were carried out to examine the intrinsic nature of these bands and electronic transitions associated with them. QC data demonstrate that bands A1 and A2 are present in almost all aromatic organic species, A3 is likely to be associated with acetophenone- and/or styrene-like groups. A4 can be attributed to the engagement of m-hydroxyaromatic and flavone-type groups typical for the polyphenolic moiety in NOM and known to be the key precursors of disinfection by-product (DBP) formation. Thus, the intensity of band A4 is predicted to be an especially strong predictor of DBP formation. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Thermodynamic and kinetic aspects of the formation of trihalomethanes and haloacetic acids determined based on the quantum chemical (QC) simulations were compared in this study with the experimental data generated using the differential spectroscopy approach in chlorination and chloramination. The ratios of the slopes of the correlations between -DlnA 350 values and individual DBPs concentrations (S NH2Cl /S HOCl) were observed to be linearly correlated with the ratios of the Gibbs free energies (ΔG NH2Cl /ΔG HOCl) of the corresponding reactions of chloramine and chlorine with acetaldehyde which was used as a model DBP precursor in QC simulations. Further QC examination of the kinetics of chlorination and chloramination of the model compound acetoacetic acid showed that the activation energy of reactions between monochloramine that directly participates in substitution reactions to form mono-, di and tri-halogenated intermediates are 2–3 times higher than those of HOCl formed via the hydrolysis monochloramine. This result confirms that the interactions of chloramine with NOM and ensuing DBP formation are primarily mediated by the free chlorine released as a result of the hydrolysis of monochloramine while direct halogenation of NOM by monochloramine is likely to provide a small contribution to DBP formation. Image 1 • -DlnA 350 is linear with most of individual DBPs yields in chlor(am)ination. • Ratio of slopes (S NH2Cl /S HOCl) for individual DBPs are linear with ΔG NH2Cl /ΔG HOCl. • Direct halogenation of NOM by NH 2 Cl contribute to small fraction of DBP formation. • The activation energy of NOM reaction with NH 2 Cl is higher than HOCl. • Tri-chlorinated HAAs and THMs are suppressed in chloramine due to trace level HOCl. [ABSTRACT FROM AUTHOR]

Tetracycline is a type of broad-spectrum, naturally occurring antibiotic that leads to several side effects, such as affecting intestinal flora and increase in bacterial resistance. The affinity of tetracycline for abiotic and biotic surfaces and metal ions is closely related to its deprotonation state and charge distribution; however, its deprotonation-protonation property remains unclear. In this study, the hydrolysis of tetracycline was investigated by combining experiments with quantum-chemical calculations. The molecular structure of the probable deprotonation states were optimized by quantum-chemical calculations, and the corresponding absorbance spectra were predicted based on frontier molecular orbital (FMO) theory. The absorbance spectra showed structure-specific features at the different deprotonation states. In addition, changes in tetracycline absorbance spectra in the pH range of 2.00–12.00 was examined by spectroscopic titration. The deprotonation was found to proceed in the order of site 3, 4, 12, and 10, which was identified by comparing the quantum-chemical calculations and experimental differential absorbance spectra (DAS). The results in this study are of great significance for further studies of the transport and fate of tetracycline in the environment. Unlabelled Image • Differential absorbance spectra (DAS) can track the deprotonation of tetracycline. • Experimental and theoretical DAS are consistent in most cases. • The features in DAS are induced by electron transitions nearby from HOMO to LUMO. • Peaks in DAS reflect the change of molecular orbital around reactive sites. • The deprotonated order of tetracycline is site 3, 4, 12 and 10, respectively. [ABSTRACT FROM AUTHOR]

• Gaussian bands in DAS reveal protonation-active functionalities in NOM. • DAS and FT-ICR-MS identify protonation-active molecules in NOM. • Genetic molecular network analysis identifies active chromophores in NOM molecules. • Molecular orbital theory interprets electronic transitions of active chromophores. Natural organic matter (NOM) is critical for the biogeochemical cycles of energy and many elements in terrestrial and aquatic ecosystems, and protonation-active functional groups in NOM molecules, notably carboxylic and phenolic groups often mediate these critical environmental functions. Molecular heterogeneity, polydispersity and dynamic behavior of NOM complicate achieving an unambiguous description of its molecular properties and reactivity. This study demonstrates that differential ultraviolet-visible (UV/VIS) absorbance spectra (DAS) of NOM acquired at varying pH values exhibit several distinct features associated with the deprotonation of NOM molecules, independent of the environmental provenance of NOM (e.g., surface water, seawater, sediment, and wastewater). The protonation-active functionalities that contribute to the Gaussian distribution bands present in the DAS were identified here by comparing characteristic properties of the bands with the stoichiometries of NOM molecules ascertained by Ultrahigh-Resolution Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS). The protonation-active individual chromophores universally present in NOM molecules were identified by a genetic molecular network analysis. The observed DAS features were closely modeled via superimposing DAS spectra of 51 individual protonation-active chromophores. Molecular orbital theory was applied to further interpret the deprotonation of these chromophores, their molecular structure, electron distribution, and electron transitions measured using DAS. The high sensitivity and easy implementation of the DAS approach allows using it as a powerful tool to quantify the molecular properties and reactivity of NOM at environmental concentrations. [Display omitted] [ABSTRACT FROM AUTHOR]

Objective: To introduce the minimally invasive Vecchietti procedure based on single-port laparoscopy with self-made surgical instruments for the surgical management of Mayer-Rokitansky-Küster-Hauser syndrome (MRKH).Design: Surgical video article. The approval of the Institutional Review Board and written consent from the patient were obtained.Setting: University hospital.Patient(s): A 22-year-old woman presented with primary amenorrhea and inability to participate in penetrative sexual intercourse. A gynecological examination revealed a phenotypically normal vulva and absence of the vagina. A normal 46,XX karyotype was expressed. Magnetic resonance imaging and ultrasonic imaging of the abdomen and pelvis indicated that the ovaries were normal in size and there was vaginal agenesis with rudimentary uterus. No other congenital malformations were present.Intervention(s): The modified Vecchietti procedure involved a transvaginal operation and laparoscopic surgery. The epidural catheter was stretched and made into two wires that were tucked into the core of the Veress needle and then folded into four strings for perineal puncture. A transverse incision of about 3 cm was made in the center of the navel, layer by layer into the abdomen, and placed in a self-made single port (made of a small wound protector and an 8-inch glove), introducing the laparoscope. Under laparoscopic surveillance, the Veress needle was inserted through the vesicorectal space guided by the index finger, which was placed in the rectum. The epidural catheter was pumped from the core into the abdominal cavity under laparoscopy. Subsequently, cystoscopy was performed to ensure that no bladder perforation occurred during the needle insertion. The ball-shaped acrylic device and the two rubber stoppers were attached to the epidural catheter of the vulva. An epidural puncture needle with wire perforated the peritoneum through McBurney's point and the opposite McBurney's point, pulling the epidural catheter out of the abdominal cavity. The epidural catheter was curled around the gauze rolls until the ball-shaped device could be accommodated into the newly created cavity at a sufficient depth. After the surgery, the top of neovagina was lifted about 1 cm every day by tightening gauze rolls to increase the traction, until a neovagina 9 cm long was achieved.Main Outcome Measure(s): The clinical and anatomical data such as the operative time, intraoperative bleeding, duration of hospitalization, and measurement of the final length of the newly created canal 30 days after surgery and 3 months after surgery.Result(s): The operative time was 30 minutes, and the intraoperative blood loss was 10 mL. The duration of hospitalization was 10 days. Before discharge, the vaginal depth was 9 cm at 5 days after the surgery, and the self-made traction system was removed. A plastic mold was then inserted using povidone-iodine. The vaginal dilator had to be worn day and night. The patient was advised to sit at the corner of a hard bed or chair from time to time to enhance the dilated effect of the vaginal mold. Three months after the surgery, it could be worn each night until regular sexual intercourse was initiated. The canal length 30 days and 3 months after the surgery was nearly 9 cm.Conclusion(s): The modified Vecchietti vaginoplasty is a simple, safe, cost-effective, and minimally invasive procedure, offering an anatomic and functional neovagina for MRKH patients. [ABSTRACT FROM AUTHOR]

Objective. To investigate the expressions of vascular endothelial growth factor (VEGF), VEGFRs and activation of signal transducers and activators of transcription (STATs) in ovarian epithelial carcinoma and the relationships among them.Methods. The tissue samples of 42 primary ovarian epithelial carcinoma, 29 benign ovarian tumor and 11 normal ovarian tissue were used to determine the expression of VEGF, VEGFR1, VEGFR2, P-STAT1, P-STAT3, P-STAT5 and P-STAT6 proteins by immunohistochemical staining.Results. VEGF in ovarian carcinomas was significantly higher than that in benign and normal ovarian tissues. VEGFRs expression was in agreement with VEGF expression. In tumor cells and endothelial cells of ovarian carcinomas, expressions of P-STAT3 and P-STAT5 were significantly higher than those in benign and normal ovarian tissues. In endothelial cells, the expression of VEGFR1 and P-STAT5 closely correlated with each other, as well as VEGFR2 and P-STAT3. However, in ovarian carcinoma cells, expressions of VEGF, VEGFR1 and VEGFR2 were significantly correlated with P-STAT3 and P-STAT5, but not with P-STAT1 and P-STAT6.Conclusions. There exist overexpressions of VEGF, VEGFRs, and STAT3, STAT5 activation. Furthermore, these results indicate that VEGF secreted by ovarian carcinoma cells may activate STAT pathway via VEGFRs in ovarian carcinoma themselves. [Copyright &y& Elsevier]