Identification and classification of components in flash pyrolysis oil and hydrodeoxygenated oils by two-dimensional gas chromatography and time-of-flight mass spectrometry.

Hydrodeoxygenated pyrolysis oils (HDO) are considered promising renewable liquid energy carriers. To gain insights in the various reaction pathways taking place during the hydrodeoxygenation reaction of pyrolysis oil, two-dimensional gas chromatography with time-of-flight mass spectrometric analyses (2D-GC-TOF-MS) was applied on the feedstock and product oil. Chromatographic parameters like injection temperature and column choice of the 1D-(2)D ensemble are discussed. Fractionation of the oils by hexane extraction was applied to show the distribution of analytes over the phases. Some 1000 and 2000 components in the pyrolysis and HDO oil, respectively could be identified and classified. The TOF-MS detection considerably improved the understanding of the molecular distribution over the 1D-(2)D retention time fields in the contour plot, in order to classify the analytes in functional groups. By group-type classification of the main components (>0.3% relative area), it was possible to characterize the oils by 250 and 350 analytes, respectively pyrolysis oil and HDO oil, describing 75% of the chromatographable fraction. The 2D-GC-TOF-MS method showed to be a useful and fast technique to determine the composition of (upgraded) pyrolysis oil and is potentially a very useful tool for exploratory catalyst research and kinetic studies. The 2D-GC-TOF-MS technique is not only useful for the chemical study as such, but also provides the basic knowledge for method transfer to a 2D-GC-FID (flame ionization detector) application.

Identification of components in fast pyrolysis oil and upgraded products by comprehensive two-dimensional gas chromatography and flame ionisation detection.

Pyrolysis oil and upgraded products are promising energy carriers. Characterisation of the oils is hampered due to the presence of a large number of components (>400) belonging to a broad variety of chemical compound classes (i.e., acids, aldehydes, ketones). In this study, a comparison of the capabilities of 2D-GC-FID and GC-MS to determine the molecular composition of these oils is made. As such, it represents a chromatographic study for a real application in green catalytic technology. Split-injection of the oil samples, diluted in tetrahydrofuran (THF), was applied without any sample pre-treatment. GC-MS application resulted in coelution, while 2D-GC showed significantly higher chromatographic resolution. Model compound mixtures were used for compound identification in the 2D-GC analysis while GC-MS was used to confirm the molecular structures. The combination of both 2D-GC-FID and GC-MS proved to be a useful method, without the requirement of a 2D-GC/TOF instrument. The technique was applied successfully to identify and quantify the main components in pyrolysis oil and upgraded pyrolysis oil made by hydrodeoxygenation (HDO) technology. Compared to GC-MS, 2D-GC-FID provides a fast overview of the various chemical compound classes present in the oils.

Developmental regulation of neural response to FGF-1 and FGF-2 by heparan sulfate proteoglycan.

Murine neural precursor cells and cell lines derived from them are stimulated by members of the heparin-binding fibroblast growth factor (FGF) family. The activity of FGF is regulated by heparan sulfate proteoglycans (HSPGs), and this interaction is an essential prerequisite for the binding of growth factor to the signal transducing receptors. Messenger RNA for FGF-2 was detectable in the neuroepithelium at embryonic day 9, and the HSPGs produced by these cells at this time preferentially bound FGF-2. However, at embryonic day 11, when messenger RNA for FGF-1 was first detectable, there was a switch in the binding specificity of the HSPG to FGF-1. Thus, a single species of HSPG undergoes a rapid, tightly controlled change in growth factor-binding specificity concomitant with the temporal expression of the FGFs.

Delayed interval delivery of two remaining fetuses in quintuplet pregnancy after embryo reduction: report and review of the literature.

A case report is presented with a prolonged interval between delivery of 25 days. A quintuplet pregnancy resulted from hormonal stimulation of ovulation. Two fetuses remained after an embryo reduction was performed at 11 weeks gestation. At 22.5 weeks gestation the first twin (310 g) was delivered after spontaneous rupture of membranes. Using tocolytic agents, the second twin (710 g) was born at 26 weeks of gestation. This case is discussed and a review of the literature is given.

PIP: In Holland, infertility specialists at Sophia Hospital in Zwolle administered human menotropins chorionic gonadotropin injections to a 26-year old woman to induce ovulation. Donor artificial insemination resulted in conception. At 8 weeks gestation, ultrasonography revealed 5 fetuses. Since quintuplet pregnancies increase the risk of maternal complications and of perinatal morbidity and mortality, she consented to embryo reduction at 11 weeks gestation, resulting in a twin pregnancy. Between 16-18 weeks gestation, she had some vaginal bleeding. At 22.5 weeks gestation, she suffered lower abdominal pain and fluid loss and delivered a 310 fm female who died within a few hours. The physicians ligated the umbilical cord with vicryl near the cervix. The gestational sac of twin B was sticking out of the internal ostium, but she did not deliver twin B. There were no signs of placental separation or of infection. The woman and her husband agreed to postpone delivery of the 2nd fetus. She remained in bed while receiving iv tocolytic drugs (ritodrine R). The physicians also administered iv antibiotics for 3 days (ampicilline and cefotaxim). Weekly ultrasound examination showed that twin B grew normally. A subfebrile temperature and an increase in the white blood cell count resulted in restart of antibiotic therapy. Health workers gave her intramuscular injections of betamethasone to accelerate development of the fetus' lungs at 26 weeks. 2 days later, she went into labor. The physicians ruptured the membranes and delivered a 710 gm male newborn. She later delivered 3 intact amniotic sacs with autolytic fetuses. She recovered uneventfully. The newborn eventually developed bronchopulmonary dysplasia and dies at 3 months. None of the 1st-born infant in 14 delayed interval delivery cases reported in the literature since 1957 survived. 13 of the 17 later born infants did survive. Tocolytic agents were used to postpone delivery in 10 cases. Cervical cerclage was done in the 7 other cases. All but 1 case received broad-spectrum antibiotics.