The Effect of Anesthesia Method on Melatonin Level and Its Relationship With Postpartum Depression in Cesarean Section Patients.

Objective Our study aimed to establish the effects of anesthetic agents used in cesarean sections on melatonin levels and to evaluate the possible association between melatonin levels and postpartum depression. Materials and methods Our study was approved by the Erzincan Binali Yildirim University Ethics Committee (approval number: 25.07.2017 11/11). We included 231 pregnant women between the ages of 18 and 45 who were admitted for a cesarean section to Erzincan Mengücek Gazi Training and Research Hospital Anesthesiology and Reanimation Clinic. The pregnant women were divided into three groups that underwent general, spinal, and combined spinal-epidural anesthesia, respectively. These approaches were determined by the preference of the attending anesthesiologist. On the postoperative first day at 5:00 am, peripheral venous blood samples were obtained from the subjects for melatonin level measurement. Samples were centrifuged and kept in -80 °C until the testing for melatonin with the enzyme-linked immunosorbent assay (ELISA) method. In order to determine the depression status, the subjects were evaluated with the Edinburgh Postpartum Depression Scale. Results Of all the anesthesia types given to the subjects, 16% was combined spinal-epidural anesthesia, 18.2% was general anesthesia, and 65.8% was spinal anesthesia. According to the scale, 68% of the subjects had no depression and 32% had depression. The depression rate in subjects who underwent general anesthesia was significantly higher than in other groups (p<0.001). The association between the anesthesia method and melatonin levels had no statistically significant difference (p=0.53). The association between depression status and melatonin levels had no statistically significant difference among the two groups (p=0.097). Conclusion We aimed to evaluate the effect of the chosen anesthesia method on postoperative melatonin levels and postpartum depression and found that the chosen method of anesthesia does not affect postoperative melatonin levels significantly but the usage of general anesthesia significantly raises the postpartum depression rate among subjects. We also did not find any correlation between postoperative melatonin levels and postpartum depression.

Thioxanthone Dioxide Triplet States Have Low Oxygen Quenching Rate Constants.

With few exceptions, triplet excited states of organic molecules, 3M1, are quenched by ground state molecular oxygen, O2(X3Σg-), with rate constants kq greater than ∼109 M-1 s-1 in fluid solutions. If the energy of the triplet state is above 94 kJ/mol, then such quenching can result in the sensitized production of singlet oxygen, O2(a1Δg). In the interaction between 3M1 and O2(X3Σg-), the magnitudes of both kq and the yield of the O2(a1Δg) depend appreciably on mixing with the M-O2 charge-transfer state. Here, we report that triplet states of several thioxanthen-9-one-10,10-dioxide derivatives have unusually low kq values (as low as ∼1 × 108 M-1 s-1) but have quantum yields for the photosensitized production of O2(a1Δg) that approach unity. Because these molecules possess high oxidation potentials (∼3.5 V vs SCE), we suggest that charge transfer character in the 3M1-O2(X3Σg-) encounter complex is reduced, thereby lowering kq while maintaining high O2(a1Δg) yields. These results provide important experimental support for existing models for the quenching of organic molecule excited states by O2(X3Σg-).

The synthesis and characterization of polyorganosiloxane nanoparticles from 3-mercaptopropyltrimethoxysilane for preparation of nanocomposite films via photoinitiated thiol-ene polymerization.

This article describes the synthesis of modified silica nanoparticles (SiO2-MPTMS) via the condensation reaction carried out between silanol moieties of silica nanoparticles and the trialkoxy silyl groups of (3-mercaptopropyl) trimethoxysilane (MPTMS). Then, SiO2-MPTMS nanoparticles in certain amounts (0.5 wt %, 1 wt %, 2.5 wt % and 5 wt %) were incorporated into thiol-ene resins consisting of bisphenol A glycerolate dimethacrylate and trimethylolpropane tris(3-mercaptopropionate) to prepare nanocomposite films via the photoinitiated thiol-ene polymerization in presence of 2,2-Dimethoxy-2-phenylacetophenone 99% as a photoinitiator. Fourier transform infrared spectroscopy, dynamic light scattering, scanning transmission electron microscopy, thermal gravimetric analyzer, and X-ray photoelectron spectrometer were employed to characterize SiO2-MPTMS nanoparticles. It was revealed that the nanosilica surface was successfully grafted by MPTMS with the grafting ratio of 22.9%. Properties of the nanocomposite films such as decomposition temperature, thermal glass transition temperature, tensile strength, hardness, and particle distribution were investigated and the results were compared with each other and neat film. The addition of MPTMS-modified silica particles did not improve the thermal stability of the films. In scanning electron microscopy study, it was seen that 2.5 wt % of these nanoparticles used as additives were about 200 nm in size and dispersed homogeneously in the polymer matrix. The increase in tensile strength of nanocomposite films compared to the neat film was measured as 77.3% maximum.