Graphite Oxide and Aromatic Amines: Size Matters

Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molecules prefer to covalently connect to the graphene oxide matrix via chemical grafting, while napthalene amine molecules bind with the graphene oxide surface through π–π interactions. The presence of intercalated aromatic molecules between the graphene oxide layers is demonstrated by X‐ray diffraction, while the type of interaction between graphene oxide and polycyclic organic molecules is elucidated by X‐ray photoelectron spectroscopy. Combined quantum mechanical and molecular mechanical calculations describe the intercalation mechanism and the aniline grafting, rationalizing the experimental data. The present work opens new perspectives for the interaction of various aromatic molecules with graphite oxide and the so‐called “intercalation chemistry”.     

Lorazepam-valproate interaction: studies in normal subjects and isolated perfused rat liver

Valproate (VPA) has been shown to interact with all the major antiepileptic drugs (AEDs) through two mechanisms of action: displacement from albumin binding sites and inhibition of drug metabolism. More recently, evidence showed that VPA inhibits the elimination of drugs metabolized by glucuronide conjugation. Lorazepam (LZP), which is primarily eliminated by conjugation with glucuronic acid, is administered concurrently with VPA both in treatment of epilepsy and in patients treated with VPA for psychiatric disorders. Therefore, a significant drug interaction is likely. We investigated such interaction both in in vitro isolated perfused rat liver (IPRL) and in normal subjects. LZP [2 mg, intravenous (i.v.) bolus] was administered to 8 normal volunteers before and after chronic dosing with VPA. In 6 of 8 subjects, VPA significantly decreased LZP plasma clearance by an average of 40% (p < 0.05) and increased LZP concentrations by decreasing formation clearance of the LZP glucuronide. In the IPRL studies, VPA also significantly decreased formation of LZP glucuronide (from 0.72 +/- 0.14 to 0.22 +/- 0.15 ml/h/kg, p < 0.05), indicating that IPRL is a useful tool for evaluation of the effect of VPA on drugs eliminated by glucuronide conjugation.     

Time and cost securing in complex large-scale projects

Meeting time and cost objectives in complex projects involves specific problems and risks. An attempt is made to analyse the components of total cost increase of a project caused by time delay. An outline is given as to how these considerations can be used to estimate cost increases in investors' decision situations as well as to ascertain fair contractual penalties and claims for compensation and for the evaluation of justified project acceleration costs.     

Underrecognition of cervical Neisseria gonorrhoeae and Chlamydia trachomatis infections in the emergency department

OBJECTIVES: 1) To quantify the frequency of underrecognized Neisseria gonorrhoeae and Chlamydia trachomatis cervical infections in women tested in the ED, 2) to describe and compare the characteristics of those treated and not treated during the initial visit, and 3) to quantify the delay interval until treatment was provided. METHODS: A 2-year, retrospective consecutive case series was performed from June 1, 1992, to May 31, 1994. There were 148 women with > or = 1 discrete occurrence of culture-proven cervical N. gonorrhoeae or C. trachomatis infection studied. All the patients were evaluated in a university-affiliated, tertiary care hospital-based ED with a large rural referral area. The main outcome measures were the proportions of patients with positive cultures both treated and not treated in the ED, the clinical characteristics of each group, and the proportion remaining untreated or experiencing treatment delays of > 2 weeks after attempted phone, mail, and public health follow-up. RESULTS: Of 157 occurrences of positive cultures for N. gonorrhoeae or C. trachomatis, 86 (53%) were treated with a regimen suggested by the CDC prior to ED release. The proportion of women with isolated C. trachomatis infections that were underrecognized and untreated initially was larger than the proportions with isolated N. gonorrhoeae or combined infections (79% vs 27% and 53%, respectively, p < 0.0001). Women with findings suggestive of advanced disease (history of fever or chills, or examination evidence of temperature > 38 degrees C, purulent vaginal discharge, or any uterine/salpinx/ovarian tenderness) were more often recognized and treated with appropriate antibiotics initially (p = 0.02 to < 0.00001 for all). After phone, mail, and public health follow-up, treatment could not be documented for 25% of the occurrences, in all cases due to an inability to locate the patient. An additional 20% of the women did not receive treatment for 14-60 days. CONCLUSIONS: In this population, both N. gonorrhoeae and C. trachomatis cervical infections are frequently underrecognized in the ED, with isolated C. trachomatis infections associated with significantly higher proportions of underrecognition. Many affected women remain untreated for extended intervals, creating public and individual health risks. Improved point of contact detection, follow-up, and treatment policies are needed to limit these risks.