Experimental Study of the Formation of Organosulfates from α-Pinene Oxidation. 2. Time Evolution and Effect of Particle Acidity.

The present work is an extensive laboratory study of organosulfate (OS) formation from the reaction of α-pinene oxidation products or proxies with acidified ammonium sulfate aerosols in three different acidity conditions ((NH4)2SO4 0.06 M; (NH4)2SO4/H2SO4 0.06 M/0.005 M; (NH4)2SO4/H2SO4 0.03 M/0.05 M). The kinetics of the reactions of α-pinene, α-pinene oxide, isopinocampheol, pinanediol, and myrtenal with ammonium sulfate particles were studied using a quasi-static reactor. The reaction of α-pinene oxide with the highly acidic ammonium sulfate particles was determined to be 7, 10, 21, and 24 times faster than for isopinocampheol, α-pinene, pinanedial, and myrtenal, respectively, for an OS precursor concentration of 1 ppm and after 1 h reaction time. The effective rate coefficients for OS formation from α-pinene oxide were determined to be 2 orders of magnitude higher in highly acidic conditions than for the two other acidity conditions. For α-pinene oxide reactions with highly acidic ammonium sulfate particles, OS formation was observed to increase linearly with (i) the time of reaction up to 400 min (r2 > 0.95) and (ii) α-pinene oxide gas-phase concentration. However, OS formation from α-pinene oxide reactions with slightly acidic or pure ammonium sulfate particles was limited, with a plateau ([OS]max = 0.62 ± 0.03 µg) reached after around 15-20 min. Organosulfate dimers (m/z 401 and m/z 481) were detected not only with highly acidic particles but also with slightly acidic and pure ammonium sulfate particles, indicating that oligomerization processes do not require strong acidity conditions. Dehydration products of organosulfates (m/z 231 and m/z 383) were observed only under highly acidic conditions, indicating the key role of H2SO4 on the dehydration of organosulfates and the formation of olefins in the atmosphere. Finally, this kinetic study was completed with simulation chamber experiments in which the mass concentration of organosulfates was shown to depend on the available sulfate amount present in the particle phase (r2 = 0.96). In conclusion, this relative comparison between five organosulfate precursors shows that epoxide was the most efficient reactant to form organosulfates via heterogeneous gas-particle reactions and illustrates how gas-particle reactions may play an important role in OS formation and hence in the atmospheric fate of organic carbon. The kinetic data presented in this work provide strong support to organosulfate formation mechanisms proposed in part 1 ( J. Phys. Chem. A 2016 , 120 , 7909 - 7923 ).

Experimental Study of the Formation of Organosulfates from α-Pinene Oxidation. Part I: Product Identification, Formation Mechanisms and Effect of Relative Humidity.

In the present study, quasi-static reactor and atmospheric simulation chamber experiments were performed to investigate the formation of α-pinene-derived organosulfates. Organosulfates (R-OSO3H) were examined for the reactions between acidified ammonium sulfate particles exposed to an individual gaseous volatile organic compound, such as α-pinene and oxidized products (α-pinene oxide, isopinocampheol, pinanediol and myrtenal). Molecular structures were elucidated by liquid chromatography interfaced to high-resolution quadrupole time-of-flight mass spectrometry equipped with electrospray ionization (LC/ESI-HR-QTOFMS). New organosulfate products were detected and identified for the first time in the present study. Reaction with α-pinene oxide was found to be a favored pathway for organosulfate formation (C10H18O5S) and to yield organosulfate dimers (C20H34O6S and C20H34O9S2) and trimers (C30H50O10S2) under dry conditions (RH < 1%) and high particle acidity and precursor concentrations (1 ppm). The role of relative humidity on organosulfate formation yields and product distribution was specifically examined. Organosulfate concentrations were found to decrease with increasing relative humidity. Mechanistic pathways for organosulfate formation from the reactions between α-pinene, α-pinene oxide, isopinocampheol, or pinanediol with acidified ammonium sulfate particles are proposed.

Characterisation of CIME, an experimental chamber for simulating interactions between materials of the cultural heritage and the environment.

An approach consisting in combining in situ and laboratory experiments is often favoured for investigating the mechanisms involved in the weathering of the materials of the cultural heritage. However, the realistic simulation in the laboratory of the environmental conditions ruling the interactions of atmospheric compounds with materials is a very complex task. The aim of this work is to characterise CIME, a new chamber specially built to simulate the interactions between materials of the cultural heritage and the environment. The originality of this instrument is that beside the usual climatic parameters (temperature, relative humidity, solar radiation) and gaseous pollutants, it also allows the controlled injection of different types of particulate matter such as terrigenous, marine and anthropogenic. Therefore, varied realistic atmospheric environments (marine or urban) can be easily simulated within CIME. In addition to the technical description of CIME, this paper shows the first results obtained by the impact of gaseous pollutants on non-durable glass, bronze and limestone. The first experiments for the deposition of different particles (calcite, clays, soot and halite) are also presented.

Atmospheric fate of a series of carbonyl nitrates: photolysis frequencies and OH-oxidation rate constants.

Multifunctional organic nitrates are potential NO(x) reservoirs whose atmospheric chemistry is somewhat little known. They could play an important role in the spatial distribution of reactive nitrogen species and consequently in ozone formation and distribution in remote areas. In this work, the rate constants for the reaction with OH radical and the photolysis frequencies of α-nitrooxyacetone, 3-nitrooxy-2-butanone, and 3-methyl-3-nitrooxy-2-butanone have been determined at room temperature at 1000 mbar total pressure of synthetic air. The rate constants for the OH oxidation were measured using the relative rate technique, with methanol as reference compound. The following rate constants were obtained for the reaction with OH: k(OH) = (6.7 ± 2.5) × 10(-13) cm(3) molecule(-1) s(-1) for α-nitrooxyacetone, (10.6 ± 4.1) × 10(-13) cm(3) molecule(-1) s(-1) for 3-nitrooxy-2-butanone, and (2.6 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) for 3-methyl-3-nitrooxy-2-butanone. The corresponding photolysis frequencies extrapolated to typical atmospheric conditions for July first at noon at 40° latitude North were (4.8 ± 0.3) × 10(-5) s(-1), (5.7 ± 0.3) × 10(-5) s(-1), and (7.4 ± 0.2) × 10(-5) s(-1), respectively. The data show that photolysis is a major atmospheric sink for these organic nitrates.

[Uterine leiomyosarcoma. Nine case reports, review of the literature]. / Le léiomyosarcome utérin. A propos de 9 observations, revue de la littérature.

OBJECT OF THE STUDY: To evaluate management and outcome of the treatment of uterine leiomyosarcoma. PATIENTS AND METHODS: Retrospective study of a series of 9 patients treated for uterine leiomyosarcoma in this hospital from 1982 to 1994. RESULTS: The condition is rarely suspected preoperatively, diagnosis is usually made on histological examination of the operative specimen. The outcome is related to the mitotic activity of the tumour and to the infiltration of nearly structures. Surgery is the only effective treatment, chemotherapy is ineffective, adjuvant radiotherapy improves local control of the tumour but has no incidence on survival. CONCLUSION: In the absence of an effective adjuvant treatment uterine leiomyosarcoma bears a poor prognosis with the only exception of small non infiltrating tumours with a low mitotic activity.

[Term birth of a twin after the rupture of the uterine horn at 15 weeks gestational age]. / Naissance à terme d'un jumeau après rupture d'une corne utérine à 15 semaines d'aménorrhée.

Having treated a case which resulted in the delivery at term of an intrauterine twin when the other twin had been lost after the rupture of a uterine cornu which itself followed a salpingectomy without removal of the interstitial portion of the tube brings the authors to discuss the physiopathology and the symptomatology of such cases. They also discuss the value of resecting the interstitial portion of the tube and what management should be when there is a live intrauterine pregnancy.

[Hydranencephaly. Report of a new case]. / Hydranencéphalie. A propos d'un nouveau cas.

Hydranencephaly is the total or virtually total absence of the cerebral hemispheres, which are reduced to a membranous sac of glial tissue, with no ependymal coating, in an intact skull. This is rare disorder (0.5 per thousand births). It is classified as a circulatory encephalopathy. Two opposing theories are generally advanced: the encephaloclastic or destructive theory and the theory of dysontogensis or malformation, due to early disruption of organogenesis. It has many causes (vascular, viral, parasitic, genetic, toxic, estrogenic...). It appears to be readily diagnosed by ultrasound, the neurological findings may be normal at birth, but transillumination of the skull remains a simple and reliable diagnostic test. Transfontanellar ultrasound, CT scanning and anatomical confirmation alone can establish the diagnosis. The prognosis is hopeless and there is no treatment.

[Fatal maternal streptococcus A infection after cesarean section]. / Infection maternelle mortelle à streptocoque A après césarienne.

A case is reported of an infection with Streptococcus pyogenes, occurring 24 hours after an elective Caesarean section in a 30 year old woman. She worsened during the first 48 h, with shock (Pasys less than 70 mmHg, pH 7.28) as well as abdominal tenderness and guarding. Laparotomy revealed peritonitis, and subtotal hysterectomy was carried out. Gram positive cocci were found in the peritoneal exudate, with bacterial cultures yielding Streptococcus pyogenes. Histopathological examination of the specimen revealed necrosing endomyometritis with septic thrombophlebitis. During the immediate post-operative period, there were several prolonged episodes of circulatory arrest treated with dobutamine, adrenaline, and noradrenaline. Multiple organ failure occurred during the next five days, despite antibiotic therapy (vancomycin, tienamycin, amikacin) and intensive care. It included jaundice, thrombocytopaenia (10 G.l(-1] adult respiratory distress syndrome (ARDS). A further laparotomy was carried out because of abdominal and thigh cellulitis, with completion of the hysterectomy and bilateral salpingo-oophorectomy. Streptococcus pyogenes was still present in the peritoneal cavity. There followed an improvement, with a return to normal of the platelet count, haemodynamic stability such that vasoactive drugs were no longer needed, and a decrease in the degree of jaundice. However, the ARDS worsened, and the patient died 15 days after the Caesarean section. There have been recent reports of similar cases, suggesting an increase in the virulence of group A streptococci linked to a re-emergence of exotoxin A.

[Circumstances in the detection of carcinoma in situ of the breast. Apropos of 12 cases]. / Les circonstances de découverte des carcinomes in situ du sein. A propos de 12 cas.

In France, 7,000 women die yearly of cancer of the breast, and 25,000 new cases are registered. The seriousness of the illness and its frequency show how important it is to diagnose it early at a stage before invasion or in situ (where 95 to 100% can be cured). In 4 years, at the University Hospital of Rennes, 90 out of 446 patients who were operated on for breast lesions had invasive cancer of the breast, i.e. 20%. 12 had a carcinoma in situ of the breast (C.I.S.E.), constituting 2.6%, of which 9 were in situ duct carcinomas and 3 in situ lobular carcinomas. In situ carcinoma of the breast can take almost any clinical form (a nodule, pain in the breast, mastitis, blood stained discharge from the nipple or Paget's disease). This means that lobular carcinoma in situ is always a surprise when diagnosed histologically in a lesion that is clinically benign. Since the anatomo-pathological diagnosis is difficult, a simple examination of the breast is not to be relied on in cases of carcinoma in situ of the breast. Mammography is the only truly valuable investigation in early diagnosis of C.I.S.E.

[Lobular carcinoma in situ of the breast. Apropos of 3 cases]. / Carcinomes lobulaires in situ du sein. A propos de 3 cas.

The authors explain the particular nature of these multifocal tumors: absence of node involvement, difficulties of diagnosis, relatively favorable prognosis and a therapeutic dilemma: limited procedure with strict surveillance, subcutaneous bilateral mastectomy.