C4 Fraction Research Articles

Acute post-streptococcal glomerulonephritis in children of French Polynesia: a 3-year retrospective study

The aim of this study was to define the current demographic, clinical and prognostic characteristics of acute post-streptococcal glomerulonephritis (APSGN) in French Polynesia and to compare these features with those of other populations. Fifty children, all of whom were <15 years old and had been admitted to the Territorial Hospital of Papeete for APSGN between January 2005 and December 2007, were retrospectively enrolled in the study. Diagnostic criteria were microscopic or macroscopic haematuria, decreased C3 fraction of the complement and evidence of recent streptococcal infection. The annual incidence was 18 cases per 100,000 children <15 years of age in 2007. Most of the children (98%) enrolled in the study were of Polynesian ethnic origin, 27 were male (54%), and the average age at presentation was 6.7 years. Signs of previous respiratory infections were clearly evident in 40% of the children. Most of the patients presented during the rainy season, correlating with the relatively high incidence of skin infections at this time. The majority of patients had proteinuria (98%), with 25% having proteinuria in the nephrotic range (proteinuria/urinary creatinine >3 g/g). The presentation was severe in 22% of the children (congestive cardiac failure, severe hypertension and/or encephalopathy), and renal failure was an initial presenting symptom in 43.7%. The C3 fraction was lower in severe presentations, but the type of haematuria, level of proteinuria and inflammatory syndrome were not correlated with immediate severe forms or with initial renal failure. Haematuria resolved in a mean of 7.7 months and proteinuria in a mean of 3.9 months. None of the children had hypocomplementemia for more than 8 weeks. Acute post-streptococcal glomerulonephritis is endemic among French Polynesians, and they can be considered to be a high-risk population. Despite a high incidence of skin infections, however, the predominance of respiratory infections potentially indicates that French Polynesia is on the way to become a low-incidence area. Systematic detection and treatment of group A Streptococcus should be intensified.

Efficacy of Cognitive Behavioural Therapy for the Treatment of Chronic Stress in Patients with Lupus Erythematosus: A Randomized Controlled Trial

Background: Chronic stress worsens the quality of life (QOL) of lupus patients by affecting their physical and psychological status. The effectiveness of a cognitive-behavioural intervention in a group of patients with lupus and high levels of daily stress was investigated. Methods: Forty-five patients with lupus and high levels of daily stress were randomly assigned to a control group (CG) or a therapy group (TG); they received cognitive behavioural therapy (CBT) which consisted of ten consecutive weekly sessions. The following variables were evaluated at baseline and at 3, 9 and 15 months: (1) stress, anxiety, depression, (2) Systemic Lupus Erythematosus Disease Activity Index, somatic symptoms, number of flares, (3) anti-nDNA antibodies, complement fractions C3 and C4 and (4) QOL. A multivariate analysis of repeated measures and various analyses of variance were carried out. Results: We found a significant reduction in the level of depression, anxiety and daily stress in the TG compared to the CG and a significant improvement in QOL and somatic symptoms in the TG throughout the entire follow-up period. We did not find any significant changes in the immunological parameters. Conclusions: CBT is effective in dealing with patients suffering from lupus and high levels of daily stress as it significantly reduces the incidence of psychological disorders associated with lupus and improves and maintains patients’ QOL, despite there being no significant reduction in the disease activity index.

CMV Enteritis Causing Massive Intestinal Hemorrhage in an Elderly Patient

Background. Cytomegalovirus (CMV) disease is rare in previously immunocompetent patients. We report a case of CMV enteritis complicated by massive intestinal bleeding. Case History. A 72-year-old immunocompetent patient was admitted for diarrhea and abdominal pain. Aspecific pattern of duodenitis was found at abdomen computed tomography and on biopsies during endoscopy. A diagnosis of vasculitis was suspected on the basis of the clinical and biological course (skin lesions, arthralgias, proteinuria, low complement C3 and C4 fractions, etc.) and pulse steroid therapy was prescribed. The patient developed multiple episodes of intestinal bleeding with shock and required urgent laparotomy. Jejunitis due to CMV vasculitis was proven by histological examination of the operative specimen. Treatment with ganciclovir was initiated. No bleeding recurrence was noted. No other lesions from CMV infection were observed. The patient died from unrelated complications. Discussion. CMV enteritis is a rare cause of intestinal bleeding particularly in previously immunocompetent patients. Aging could be accompanied by a relative immune weakness and specific antiviral therapy seems to be indicated.

Multi-scale simulation of the 1,3-butadiene extraction separation process with an ionic liquid additive

A multi-scale simulation method is proposed to enable screening of ionic liquids (ILs) as entrainers in extractive distillation. The 1,3-butadiene production process with acetonitrile (ACN) was chosen as a research case to validate the feasibility of the methodology. Ab initio calculations were first carried out to further understand the influence of ionic liquids on the selectivity of ACN and the solubility of C4 fractions in [CnMIM][PF6](n = 2–8), [C2MIM][X] (X = BF4−, Cl−, PF6−, Br−), by investigating the microstructure and intermolecular interaction in the mixture of C4 fractions and several selected ionic liquids. It was found that the selectivity of the ionic liquid is determined by both its polarity and hydrogen-bonding ability. Based on the analysis, a suitable ionic liquid was chosen. With the ab initio calculation, a priori prediction of thermophysical data of the IL-containing system was performed with COSMO-RS. The calculation revealed that the selectivity of the extractive solvent was increased by an average of 3.64% after adding [C2MIM][PF6]. With above calculations, an improved ACN extraction distillation process using ILs as an entrainer was proposed, and a configuration for the new process was constructed. Based on the established thermodynamic models which have considered the properties from the molecular structure of ILs, process simulation was performed to obtain the process parameters which are important for the new process design. The simulation results indicated that the temperatures at the bottom of the extractive distillation column with the ionic liquid as an additive are lowered by an average of 3.1 °C, which is significant for inhibition of polymerization. We show that the ACN consumption using this process can be lowered by 24%, and the energy consumption can likewise be lowered by 6.62%.

Nine-Lumped Kinetic Models ofLiquefied Petroleum Gas Under Aromatization Reaction Conditions

Abstract The aromatization reaction of liquefied petroleum gas has been studied by using three liquefied petroleum gases as the raw material and LBO-A as the catalyst. Nine-lump kinetics model networks have been put forward on the basis of lumped theory and the aromatization reaction mechanism. In the network, the aromatization reaction species are firstly lumped into C4=, C40, n-paraffin, i-paraffin, olefins, aromatics, C2-3=, H2 + C1-30, and coke. A mathematical method is first introduced to study the product distribution of the liquefied petroleum gas aromatization reaction. The results from experimental data are in accordance with the quantitative analytical conclusions drawn from the calculated data. Introduction In 1994, 1.27 hundred million tons of petroleum were processed, more than 2.2 million tons of ethylene were produced, and the resources of liquefied petroleum gas (C4 fraction and C5 fraction) reached approximately 3.7 million tons in China(1,2). The resources of liquefied petroleum gas have become more and more abundant in China; the output of liquefied petroleum gas is more than 300 thousand tons per year(3,4). The resources of liquefied petroleum gas are mainly from three resources in China: oil and gas fields, refineries and from gas cracking(5). The resources of liquefied petroleum gas are not completely used to create higher value products, whereas most resources are burned as fuel(6). Recently, research work has focused mainly on how to use liquefied petroleum gas effectively(7,8). The various quantitatively analytical methods have been studied, but the lumped-kinetics models are seldom done. In this paper, nine-lumped kinetics models, which can predict aromatization reaction product distribution under various operating conditions and calculate the maximum deviations of the product yield between calculated results and practical values, are established for a confined fluidized bed reactor.

Malignant Lymphoma in Primary Sjögren Syndrome: Incidence and Risk Factors.

Abstract 4991 BackgroundPrimary Sjögren Symdrome (PSS) is the second common systemic autoimmune rheumatic disease whose main histological feature is a focal infiltration of the exocrine glands by activated B and T lymphocytes. PSS is considered a benign autoimmune condition with a chronic indolent course. However, several reports have noted an increased incidence of malignant lymphoma with an estimated risk of up to 44 times greater than in the normal population. The aims of the present study are to assess the cumulative incidence of lymphoma in patients diagnosed of PSS, as well as to identify risk factors for developing this condition. MethodsAll patients diagnosed since 1988 and followed-up for longer than 2 years at our institution, were included. The pathological, immunological, and clinical features of each case of PSS were retrospectively examined. These data were cross-examined with the cumulative incidence of lymphoma in this group of patients, in order to determine common findings in patients later developing lymphoid malignancies. Results272 patients had been diagnosed as having a PSS in this time period, of which 244 [9 males, 235 females; median age 58 years (range 17 to 88)] had been followed for more than 2 years. After a median follow up of 9.6 years, 11 (4.5%) patients developed a lymphoma, after 6 to 171 months from diagnosis. The cumulative risk for developing lymphoma at 5, 10 and 15 years was 3.4, 4.1, and 9.3%, respectively. Risk factors associated with the development of lymphoma were skin purpura/vasculitis, lymphopenia and low levels of C3 and C4 complement fractions. Low levels of C3 and C4 were also found to be associated with an earlier development of lymphoma. Conversely, skin purpura/vasculitis and lymphopenia were both associated with the development of lymphoma at a later stage. The hystological analysis showed mucosal-associated lymphoid tissue lymphoma in 5 patients, diffuse large B cell in 3, and follicular lymphoma in 3 cases. Clinically, lymphomas had extranodal presentation in 8 out of the 11 cases, involving the salivary glands in 5, lacrimal glands in 1, and soft tissues and lung in 1 case, respectively. Only 3 patients had received immunosuppressive therapy prior to the diagnosis of lymphoma, and EBV was not found in the histological examination of any of these cases. ConclusionPatients with PSS are at a higher risk for developing lymphoma. Our study suggests low levels of C3 or C4, as well as the presence of purpura or lymphopenia delimitates a group of patients at a higher risk, so that such patients may benefit from a closer follow up. DisclosuresNo relevant conflicts of interest to declare.

Anti-Inflammatory and Analgesic Activities of Chaenomeles speciosa Fractions in Laboratory Animals

The prescription of current existing anti-inflammatory drugs is hampered by their adverse effects over time. Botanical extracts are thought to be a potential source of a natural anti-inflammatory property with fewer adverse effects. Chaenomeles speciosa has long been used as an herbal medicine for treatment of various diseases such as rheumatoid arthritis, prosopalgia, and hepatitis. Until now there have been no reports on the specific anti-inflammatory fractions of extract of C. speciosa (ECS). In the present study the anti-inflammatory activities of different fractions of ECS were evaluated using carrageenan-induced paw edema in rats. The 10% ethanol fraction (C3) was found to have stronger anti-inflammatory effects compared with other fractions at the same dose. We also found that chlorogenic acid was one of the active constituents responsible for the anti-inflammatory effect using bioassay-guided fractionation by means of high-performance liquid chromatography. Compared with controls, fraction C3 demonstrated significant anti-inflammatory activity in the xylene-induced ear edema test (P < .01), acetic acid-induced peritoneal capillary permeability test, and the cotton pellet granuloma test in mice or rats (P < .01); it also showed marked analgesic activity in the acetic acid-induced abdominal contraction test and formalin-induced paw licking test in mice and rats (P < .05 or .01). However, fraction C3 showed no significant effect in the hot plate test in mice. These findings justify the use of the C. speciosa for treating pain and inflammation. These results support the proposal of C. speciosa fraction C3 as a potential anti-inflammatory agent.

CSF/serum quotient graphs for the evaluation of intrathecal C4synthesis

BackgroundCerebrospinal fluid (CSF)/serum quotient graphs have been used previously to determine local synthesis in brain of immunoglobulins and C3 complement component. The aim of this study was to use the same technique to construct quotient graphs, or Reibergrams, for the beta globulin C4 and to evaluate the method for assessing intrathecal synthesis in neurological disease.MethodsThe constants in the previously-defined Reibergram for immunoglobulin IgA were used to calculate the CSF/serum quotient for C4. CSF and serum were analyzed for C4, IgA and albumin from a total of 12 patients with meningoencephalitis caused by encapsulated microorganisms and 10 subjects without infections or inflammatory neurological disease, some of which had dysfunction of the blood-CSF barrier,ResultsThe formula and C4 Reibergram with the constants previously found for IgA, determined the intrathecal C4 synthesis in CSF. The intrathecal C4 fraction in CSF (C4 loc in mg/l) was compared to the C4-Index (fraction of CSF: serum for C 4/fraction of CSF: serum for albumin). There was a significant correlation between the two formulae. The CSF/Serum quotient graph was superior for detecting intrathecal synthesis of C4 under variable conditions of blood-CSF barrier permeability.ConclusionThe C4 Reibergram can be used to quantify the intrathecal synthesis of this component of the complement system in different infectious diseases of the central nervous system and is especially useful for patients with blood-brain barrier dysfunction.

Intérêt de l'immunosoustraction des immunoglobulines et de la transferrine dans le dosage de la transferrine désialylée en électrophorèse capillaire

CDT (Carbohydrate Deficient Transferrin) is considered as the most efficient biomarker of alcohol abuse available for routine use. Among the various methods developed for its measurement, capillary zone electrophoresis (CZE) on the multicapillary analyzer Capillarys2 provides high quality results at high throughput. However, the non CDT specific measurement of protein absorbance at 200 nm may bring abnormal profiles in samples from patients with high polyclonal immunoglobulin level or monoclonal component. We evaluated the automated immunosubtraction procedure developed by the manufacturer in 48 samples with abnormal electrophoretic profiles that potentially could interfere with CZE measurement of CDT. Elimination of the serum immunoglobulins raised the number of interpretable profiles from 19 (40%) to 37 (77%). The immunosubtraction procedure failed in samples with a monoclonal component present at a concentration > 60 g/L and in some samples harbouring a partially degraded C3 fraction. Six samples identified as genetic BC transferrin variants were also included in the study and submitted to an automated transferrin subtraction procedure to ascertain whether the additional peak were actually transferrin glycoforms. After treatment, two samples were classified as homozygote C for transferrin due to the persistence of one of the supposed transferrin peak. In conclusion, immunoglobulin and transferrin subtraction allow a better CDT measurement in most samples with interfering monoclonal components and avoid misclassification of suspected transferrin BC or CD variants.

Syntheses, Structures, and Catalytic Ethylene Oligomerization Behaviors of Bis(phosphanyl)aminenickel(II) Complexes Containing N‐Functionalized Pendant Groups

AbstractSeveral N‐functionalized bis(phosphanyl)amine ligands respectively containing benzyl, furfuryl, thiophene‐2‐methyl, thiophene‐2‐ethyl, and 2‐picolyl groups (1a–e) were synthesized and characterized. The ligands reacted with (DME)NiBr2 in CH2Cl2 to give their corresponding nickel complexes [Ph2PN(R)PPh2NiBr2] [R = CH2C6H5 (2a), CH2C4H3O (2b), CH2C4H3S (2c), CH2C5H4N (2d), and CH2CH2C4H3S (2e)]. The structures of these complexes were established by single‐crystal X‐ray crystallography. All these nickel complexes were highly active towards ethylene oligomerization in the presence of methylaluminoxane or Et2AlCl, producing a high content of butene (C4). Especially for 2e, which contains a thiophene‐2‐ethyl pendant group, the oligomerization products obtained at –40 °C contained 95.9 mol‐% C4 fraction with 100 mol‐% 1‐butene. Over 50 °C, however, these nickel complexes underwent Friedel–Crafts alkylation of toluene with ethylene and the olefin oligomers.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)

Phytochemical and antimicrobial studies of Commiphora africana (A. Rich) Engl. root extracts

The crude ethanolic extract of Commiphora africana root was partitioned with n-hexane, chloroform; water and 10% aqueous methanol and screened for chemical constituents and antimicrobial activity. The n-hexane fraction, which was the most bio-active was chromatographed on a column silica gel to give a number of purified components. The components from the n-hexane were found to be active against Staphylococcus aureus, Escherichia coli and Candida albicans. S. aureus(ATCC 13709) was susceptible to fractions C1 - 11 giving zonal inhibition of between 1 - 3 mm. Standard antibiotics - amoxillin, chloramphenicol and tetracycline were compared with the extracts in antimicrobial activity. Key words: Antimicrobial activity, Commiphora africana, phytochemical activity, root extracts.

Clinical impact of altered immunoglobulin levels in Henoch–Schönlein purpura

The aim of the present study was the identification of immunological features, present at the time of diagnosis, that would predict the severity of Henoch-Schönlein purpura and its outcome. A cohort study was carried out in a tertiary pediatric hospital of 69 children with Henoch-Schönlein purpura, in whom serum complement components C3, C4 and IgA, IgM, IgG were repeatedly determined. During the acute phase of the disease in 54/69 patients (78.3%) immunological imbalances were observed. In 24/54 cases (44.4%) certain complications involving the kidneys and the gastrointestinal tract were noted as opposed to in 3/15 children (20%) without immunologic abnormalities. In 50/69 children (72.5%), elevated serum IgA was detected and 16 of them (32%) developed renal involvement while only 1/19 children (5.3%) with normal IgA concentration had renal involvement. Considering separately the group of 9/69 children (13%) with increased IgM and those with normal IgM levels (53/69; 76.8%), irrespective of IgA and IgG concentration, we found a comparable percentage of children who had both renal and intestinal involvement without, however, developing severe complications, which were exclusively seen in patients with increased IgA (5/7 children) and reduced IgM levels. Serum C3 fraction was elevated in 26 children (37.7%) and in 73% of cases it was associated with increased serum IgA values. Renal involvement was seen in 32% of children with increased IgA values. Most importantly, elevated IgA concentration along with reduced IgM levels was associated with higher prevalence of severe complications.

The processes of benzene alkylation with n-alkenes on the sulfocation exchangers

The processes of benzene alkylation with n-alkenes C2–C3 on sulfocation exchangers are developed. The processes are deprived of the strong corrosion aggressiveness, characteristic of the industrial processes with use of AlCl3 or BF3, and do not need the periodic burning out of the formed contaminants, that is characteristic of the processes with application of zeolites. Alkylation proceeds in the liquid phase at moderate temperatures: 70–90°C in the case of alkylation with propene and n-butenes, and 130°C for the alkylation with ethylene. With the use of alkane-alkene fractions C2–C3 the conversion of alkenes process exceeds 99%, the alkylbenzene to dialkylbenzenes ratio reaches 20–25%. Peralkylation of dialkylbenzenes it not required.

Stable isotope compositions of organic carbon and contents of organic carbon and nitrogen of lacustrine sediments from sub-arid northern Tanzania

The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. Accelerate mass spectrometer (AMS) 14C ages on total OM for sediments collected from the Ngorongoro Crater Lake indicate that the sedimentation rate is approximately 17 cm/ka. The &#94813C values from the 20 cm long core (short core) show a downcore increase, whereas that of 500 cm long core (long core), show two peaks enriched in 13C and three peaks depleted in 13C. A general downcore increase in the &#61540;13C values for the short core suggests changes in the relative proportion of C3 and C4 with C4 fraction increasing downcore. Similarly, low and high peaks in the long core suggest changes in the relative proportion of C3 and C4 with low values having high proportion of C3 type of material, probably indicating changes in precipitation and lake levels in the area. Deposition of OM depleted in 13C took place during periods of high precipitation and high lake levels. Although high content of OC and nitrogen in some core sections are associated with elevated C/N ratio values, diagenetic alteration of isotope signature is unlikely to have caused OC isotope enrichment in sections having high contents of OC and nitrogen. The OC isotope record from Lake Ndutu shows a general downcore decrease in &#94813C values and contents of OC and nitrogen. Furthermore, this general trend is punctuated by a period of above normal enrichment in 13C, with &#94813C values being as high as -6‰. A downcore decrease in &#94813C values and contents of OC and nitrogen could be attributed either to climatic variability or diagenetic effect. Moreover, a peak enriched in 13C probably indicates a period of reduced precipitation, where phytoplankton used dissolved bicarbonate rather than dissolved atmospheric CO2. Lake Mesak record shows two peaks depleted in 13C that are flanked by near constant values of about -20‰. These two peaks (depleted in 13C), which most likely have high proportion of C3 type of OM, are associated with low contents of OC and nitrogen. Generally, the contents of OC and nitrogen for this lake are lowest relative to other lakes. Tanzania Journal of Science Vol. 32 (1) 2006: pp. 61-74

Study on the Preparation Conditions of Ni/Al2O3 Catalysts to Selective Hydrogenation of Butadiene in FCC C4 Fraction

Ni/Al2O3 catalysts are the promising substitutes of the Pd/Al2O3 catalysts to selective hydrogenation 1,3-butadiene in fluid catalytic cracking (FCC) C4 fraction. Preparation conditions have an important influence on the activities of the Ni/Al2O3 catalysts. The experiment results proved that the 20 wt% nickel catalyst, which were calcined at 300°C for 2 hours then reduced at 300°C for 9 hours, had the highest activity. On the basis of the temperature-programmed reduction (TPR) and x-ray diffraction (XRD) analysis, a reasonable explanation was given. This research provided a good prospect for the industrial application of the Ni/Al2O3 catalysts.

分解C4留分中の微量不純物除去技術の開発（その3）分解C4留分を用いた吸着シミュレーション

分解C4留分中の微量不純物除去技術の開発（その3）分解C4留分を用いた吸着シミュレーション

Sulfuration Pretreatment of Ni/Al2O3 Catalyst to Remove Butadiene in FCC C4 Fraction

The Ni-based catalysts have more advantages than the most widely used Pd-based catalysts in selective hydrogenating of the butadiene in fluid catalytic cracking (FCC) C4 fraction. But the selectivity and stability of the Ni-based catalysts aren't good. The sulfuration pretreatment is an effective process to improve the performance of the Ni/Al2O3 catalysts. The sulfuration conditions of the Ni/Al2O3 catalyst have been studied in this article. The results showed the fittest conditions are that the catalyst was in-situ presulfurized for 60 min by the solution of S concentration 0.07 mol/L. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis indicated that the presulfurization declined the Ni crystal dimension.

Irinotecan and Increased Triglyceride Level in Paraneoplastic Deep Venous Thrombosis (DVT): A Strange Link in An Old Problem

DVT is present in about 3–15% of cancer patients. Paraneoplastic thrombosis pathogenesis is multifactorial. Chemotherapy is frequently involved in DVT genesis as pro-inflammatory/pro-thrombotic factor. There are few data about incidence of DVT in patients treated with Irinotecan. Aim of our study is to define if thrombotic risk in patients treated with Irinotecan is increased and then which mechanism is probably involved. For this purpose we considered in our patients the complement fractions C3 and C4 and the immune circulating complex (ICC), because they activate macrophages and platelets and increase tissue factor level. Moreover we evaluated also total cholesterol and triglyceride level, cause linked with factor VII activation. We considered C3, C4, ICC, cholesterol and triglyceride level, dose density and chemotherapeutic agents used in 116 patients with solid neoplasms (62colon, 26lung, 18gastric,) and not receiving anticoagulant prophylaxis. Median age was 68.5 years (R 57–83). M/F ratio was 66/40. The threshold value of third quartile was chosen as risk cut-off (C3: 130mg/dl; C4: 32mg/dl; ICC: 2.9 mcg/ml; total cholesterol: 205mg/dl; triglycerides 120mg/dl). The statistical analysis was conducted with Yates corrected chi square test, Fisher's exact test, Odds Ratio (OR), relative risk (RR). Twenty-four patients (20%) developed DVT. The patients treated with Irinotecan were 42. DVT occurred in 14 of these patients (32%) and in 10 of the 74 patients treated without Irinotecan (14%), with a Yates corrected chi square test of 4.6 (p=0.03), a Fisher's exact test with p=0.03, an OR of 2.98 (95%CI 1.2–7.3) and a RR of 2.35 (95%CI 1.1– 4.8). C-Reactive Protein and Erythocyte Sedimentation Rate at Pearson's test were not related with C3, C4, ICC, total cholesterol and triglyceride levels. All patients treated with Irinotecan had advanced stage colon cancer. High levels of triglycerides (>120mg/dl) were present in 17 out of 42 patients treated with Irinotecan (40%) and in 17 out of 74 patients treated without Irinotecan (23%) with a Yates corrected chi square test of 3.1 (p=0.07), a Fisher's exact test with p=0.05, an OR of 2.2 (95%CI 1–5) and a RR of 1.7 (95%CI 1–3). Although most patients developing DVT have an advanced stage colon cancer and so receiving Irinotecan, the influence of chemotherapy in DVT pathogenesis in our study cannot be excluded. Probably Irinotecan could contribute to DVT increasing triglyceride levels that are linked with in vivo factor VII activation. This relief suggests also that risk factors, other than classical, should be considered in the thrombosis onset; then other drugs (i.e. hypolipemizing drugs) could be useful in paraneoplastic DVT prevention. Nevertheless these data should be confirmed in a larger cohort of patients.

On the solution of the integral equation of the conductor-like screening model for real solvents

This paper presents a new approach to solving the equation which forms the basis for the conductor-like screening model for real solvents (COSMO-RS). The approach is based on the recognition that the integral equation for the determination of the chemical potential of a surface segment as a function of screening charge density σ belongs to the class of the non-linear Hammerstein integral equations. The solution of this integral equation can be written in closed form in which the numerical values of the coefficients are determined by solving a non-linear system of equations. The algorithm for solving the COSMO-RS integral equation is described and illustrated in the case of a model problem. The new approach is then applied for the calculation of chemical potentials and infinite dilution activity coefficients, and its convergence behaviour is investigated for the systems 1-butyne/n-butane and n-hexane/water. Calculations of infinite dilution activity coefficients γ∞ are reported for a representative set of organic compounds in aqueous solutions and in n-hexane at 298.15K, and are compared with experimental results and those from calculations with a commercial program in order to demonstrate the feasibility of our approach. Finally, a simple method to calculate approximate activity coefficients is proposed and applied to a species subset of the industrially important C4 fraction.

Effect of K promotion of Fe and FeMn Fischer–Tropsch synthesis catalysts: Analysis at the site level using SSITKA

Promoting a precipitated FeCuSiO2 catalyst with Mn has been shown to significantly improve its catalytic activity for Fischer–Tropsch synthesis (FTS). Although the impact of K promotion on the activity of Fe catalysts with and without Mn addition has been studied previously, no one has previously delineated how K influences the concentration of active surface intermediates and the intrinsic site activities of Fe and, more specifically, Mn-promoted Fe catalysts. This paper addresses that issue using steady-state isotopic transient kinetic analysis (SSITKA). Adding K at relatively low concentrations to the base Fe and Mn-promoted Fe catalysts improved the catalyst activity, but the activity of the catalysts declined with the addition of an excess amount. The percentage of light olefins (C2–C4 fraction) and chain growth probability (α) were enhanced, as expected with the presence of K, regardless of Mn addition. The addition of K decreased the BET surface area and the concentration of surface exposed Fe0 atoms (as determined by CO chemisorption). The intrinsic site activities (TOFITK) of all of the Fe catalysts determined using SSITKA were essentially identical, regardless of the concentration of added K or Mn promotion. This indicates that adding K to unpromoted or Mn-promoted Fe catalysts did not greatly affect the activity of the active sites. Rather, the higher catalyst activities observed for the Fe and Mn-promoted Fe catalysts with K addition were due primarily to an increase in the number of active surface intermediates leading to hydrocarbon products.