Effect of silane-based coupling agents and acrylic acid based compatibilizers on mechanical properties of oil palm empty fruit bunch filled high-density polyethylene composites

The mechanical properties of composites consisting of high-density polyethylene (HDPE) and oil palm fibrous wastes—that is, empty fruit bunch (EFB)—have been investigated. Tensile modulus showed an increase, whereas tensile strength, elongation at break, and impact strength decreased with increasing filler loading. The strong tendency of EFB to exist in the form of fiber bundles and the poor filler–matrix interaction is believed to be responsible for the poor strength displayed by the composites. Attempts to improve these properties using two types of coupling agents, that is, 3-aminopropyltrimethoxysilane (3-APM) and 3-aminopropyltriethoxysilane (3-APE) and two types of compatibilizers, poly(propylene–acrylic acid) (PPAA) and poly(propylene–ethylene–acrylic acid), (PPEAA), are described. While almost all chemical treatments increased the stiffness of the composites, limited improvement has been observed in the case of tensile strength. This have been attributed to the presence of fiber bundles that remain intact even after several types of chemical treatment have been carried out. Thus, the role of EFB as reinforcing agent is not fully realized. Scanning electron microscopy (SEM) micrographs revealed that the main energy-absorbing mechanisms contributing towards toughness enhancement is through the fiber bundle pull-out process. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2189–2203, 1998     

Characteristics of the heterologously expressed human lanosterol 14α‐demethylase (other names: P45014DM,CYP51, P45051) and inhibition of the purified human and Candida albicans CYP51 with azole antifungal agents

Human and Candida albicans CYP51 were purified to homogeneity after GAL10‐based heterologous expression in yeast in order to resolve the basis for the selective inhibition of the fungal enzyme over the human orthologue by the azole drugs ketoconazole and itraconazole, used in the treatment of systemic fungal infection. The purified proteins have similar spectral characteristics, both giving a maximum at 448 nm in reduced carbon monoxide difference spectra. Substrate affinity constants of 20·8 and 29·4 μM and V_max of 0·15 and 0·47 nmol/min/nmol were observed for C. albicans and human enzymes, respectively, in reconstituted enzymatic assays, using an intermediate of the demethylation reaction [32‐³H]‐3β‐hydroxylanost‐7‐en‐32‐ol as the substrate. Both enzymes gave similar type II spectra on titration with drugs, but a reduced affinity was observed for human CYP51 using the ability of carbon monoxide to displace the drug as a ligand and by calculation of IC₅₀. However, although the results indicate higher affinity of the drugs for their target CYP51 in the major fungal pathogen C. albicans, when compared directly to CYP51 from humans, the difference was less than 10‐fold. This difference is an order of magnitude lower than previously reported data based on measurements using unpurified human CYP51 enzyme preparations. Consequently, increased azole doses to combat resistant candidaemia may well inhibit endogenous human CYP51 and the potential consequences are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Preparation and quality assessment of CuS thin films encapsulated in glass

Copper sulfide (CuS)-based thin films with different thickness have been prepared by thermal co-evaporation of the elemental constituents. Morphological and microstructural properties were shown to vary with film thickness. Optical properties of films encapsulated in a double-glazed configuration and containing an air gap have been measured. Encapsulated CuS films of thickness 100 and 150 nm showed high transmittance peak values of 48% and 36%, respectively, and a low reflectance below 20% and 15%, respectively, in the visible region. A low transmittance of ~ 10% (~ 15%) and a high reflectance of ~ 45% (~ 40%) in the near-infrared region were obtained for the film with 150 nm (100 nm). Thermal stability of the films has been proved by annealing of the films in air and Argon at 150 °C.     

Influence of Process Variables on the Reactivity of Low Formaldehyde Emission Urea-Formaldehyde Resin

One of the important characteristics of the thermosetting resins such as urea-formaldehyde resin is the cure property. This is an invaluable characteristic for determining the processing capabilities of the resin. Differential scanning calorimetry (DSC) measurements are ideally suited to achieve this end. This paper presents the results of the effect of process variables on the enthalpy of cure of a low formaldehyde emission UF resin prepared by a four-stage process as described in the text. Response surface methodology (RSM) was used to design and the analyze the experiments. Urea (U) was added to the reaction mixture according to a pre-determined program of varying the number of additions and the duration between the additions during the second stage of the process. A mathematical relationship between the process variables and enthalpy of cure was established. The urea-formaldehyde (UF) resin was prepared under optimum conditions. Experiments were performed with the resin so prepared to determine the energy of activation of the curing reaction catalyzed by ammonium chloride.     

Survival of multiple myeloma patients who are potential candidates for early high-dose therapy intensification/ autotransplantation and who were conventionally treated

PURPOSE: To analyze the outcome of patients with multiple myeloma (MM) who were potential candidates for early high-dose therapy (HDT) intensification followed by autotransplantation from a series treated with conventional chemotherapy. PATIENTS AND METHODS: From January 1985 through December 1989, 487 patients with symptomatic MM were entered onto a randomized study to compare melphalan and prednisone (MP) versus vincristine, cyclophosphamide, melphalan, and prednisone (VCMP) /vincristine, carmustine (BCNU), doxorubicin, and prednisone (VBAP). The sub-group of 77 patients who could have been candidates for early intensification with HDT followed by stem-cell support (ie, < 65 years of age, stage II or III disease, performance status < 3, and objective or partial response to initial chemotherapy) are the subjects of this report. RESULTS: Seventy-seven of 487 patients could have been candidates for early intensification. The median age was 56 years (range, 27 to 64). At diagnosis, 12% had abnormal renal function, 16% hypercalcemia, and 42% serum beta 2-microglobulin level > or = 6 mg/L; 62% had stage III disease at diagnosis. Thirty-six patients were initially treated with MP and 41 with VCMP/VBAP. The median response duration to initial chemotherapy was 22 months, and the actuarial probability of being in continued first response at 5 years was 14%. After a median follow-up time of 58 months, 59 patients have died, one was lost to follow-up evaluation, and 17 are still alive 69 to 119 months after initial chemotherapy. The median survival time from initiation of treatment was 60 months and from the time when autotransplantation would be considered, 52 months. The only independent prognostic parameter for survival was renal function at diagnosis. CONCLUSION: The median survival time of patients with MM who are less than 65 years of age and who respond to initial chemotherapy is 5 years. This survival duration is similar to that reported in selected series of patients given early HDT and stresses the importance of ongoing randomized trials to determine the role of HDT in the treatment of younger myeloma patients.     

Evaluation of alternative methods for establishing safe levels of occupational exposure to vinyl halides

The facts that reduction of occupational vinyl chloride exposures to levels within or below the 0.5-5 ppm range has so far been successful in eliminating vinyl chloride-induced liver angiosarcoma and that humans appear to be less sensitive to the carcinogenic effect of vinyl chloride than rats offered an opportunity to verify or dispute risk assessment extrapolation models used, and proposed, by the U.S. EPA. Safe occupational vinyl chloride exposures were defined as levels associated with an incidence of one angiosarcoma in 100,000 exposed workers, determined from rat bioassay data using default no-threshold (linearized multistage model and benchmark dose approach with linear extrapolation) and threshold (NOEL/LOEL and benchmark dose uncertainty factor approaches) models, and then compared against the likely protective range of 0.5-5 ppm. Safe levels derived using either no-threshold model are equivalent and are two to three orders of magnitude below the 0.5-5 ppm range. Safe levels derived using either threshold model, when applying uncertainty factors which reflect equal or less sensitivity in humans compared to rats, fall within the 0.5-5 ppm range. Similar results were obtained for vinyl bromide and vinyl fluoride. These results undermine the U.S. EPA default assumption of no-threshold for vinyl halides as well as for other DNA-reactive carcinogens while simultaneously supporting the notion that a practical threshold exists. They further suggest that when threshold models are appropriate, the default assumption of greater sensitivity in humans compared to rats should be carefully evaluated.     

Myelomonocytic antigens in B-cell chronic lymphocytic leukemia

The clinical significance of myelomonocytic (MyMo) antigens in B-cell chronic lymphocytic leukemia (B-CLL) is unclear. We have analyzed the expression of MyMo antigens (CD13, CD14 (LeuM3, My4, Mo2), CD15, CD11b, CD11c, CD33 and CD68) on B-lymphocytes (CD19+) in 105 B-CLL patients and in 35 controls. A double direct staining technique and flow cytometric analysis was performed. The expression of MyMo antigens on the control group did not exceed 4% B-lymphocytes. A MyMo antigen was considered as positive when present in > or = 10% of B-lymphocytes. Among the B-CLL patients, 28 (26.7%) were positive for CD11c, 21 (20.0%) for CD11b, nine (8.6%) for CD15, five (4.8%) for CD13, two (1.9%) for Mo2, and one (1.0%) for My4. No patient was positive for LeuM3, CD33 or CD68. CD11c was more frequently expressed in patients with a short lymphocyte doubling time (< 12 months) (P = 0.05) and CD11b in the group with a higher number of lymphoid areas involved (P = 0.02). No correlation was found between lymphoid morphology and MyMo antigen expression. Fourteen of the 80 patients at risk subsequently progressed to a more advanced stage. Multivariate analysis identified hemoglobin (P = 0.004) and CD11b positivity (P = 0.009) as independent variables for disease progression. Fifteen patients died during evolution. Seven out of the 21 CD11b positive patients and eight of the 84 CD11b negative patients died (LR: P = 0.02, BG: P = 0.05). In the multivariate analysis, only CD11b positivity (> or = 10%) added prognostic value to clinical stages.     

PROCESSUS – Integration of SEI CMM and ISO quality models

Integration of the two best-known quality management models for software production and maintenance, the Capability Maturity Model and the ISO 9001 Model (including ISO 9000-3) is of great interest for both the European and the American software market. The definition of a quality management model which would conform to the requirements of both models and use the advantages of each was a key goal of our research work within the project PROCESSUS.1 Research work was conducted in two steps: first, the detailed comparison of both models was made in order to define their common issues and specifics of each model, and secondly, the integrated model based on the results of the comparison was defined. In this paper the comparison method and results are described. Further, a method for the integration and a framework of the integrated model are presented. The core of our work is actually the content of the integrated model. Due to extensive content of the integrated model examples of some parts only are given in the appendix. The integrated model presented in this paper has already been successfully used in organizations which are cooperating in the project PROCESSUS o these organizations achieved the needed maturity for certification to the ISO 9001 standard and a maturity level near level 3 of CMM.     

An Alternative Casting Technique to Improve the Creep Resistance of Cast INCONEL Alloy 740H

Metallurgical and Materials Transactions A - The increasing performance requirements of power plant designs, such as advanced-ultra supercritical (A-USC), require the use of Ni-based superalloys to...     

Photofabrication of biofiber‐based polymer matrix composites

The novel development of a photofabrication process of biofiber composites, based on oil palm empty fruit bunch fibers, is reported. The process consists of the following steps: (1) the preparation by a wet process of nonwoven mat of biofiber, either alone or in combination with glass and nylon; (2) drying the mat; (3) preparation of photocurable resin matrix, consisting of vinyl ester and photoinitiator; (4) impregnation of the mat by photocurable resin; and (5) irradiation of the impregnated mat by UV radiation to effect the cure of the composite. The nonwoven mat was formed in a “headbox” into which was poured a slurry of fibers. A wet mat was formed by after dewatering of the slurry. Biofiber, glass, and nylon fibers were mixed in different proportions. A “mixture experimental design” was used to generate experimental compositions of the reinforcing fibers and to model dependency of the response variables on the components through mathematical relationships. These relationships were meant to (1) determine the effect of composition of the reinforcing fibers on the physical and mechanical properties, (2) predict the response for any unknown composition of fibers, and (3) determine the optimum values of any identified properties. Because the product was characterized by multiple responses, simultaneous maximization of all properties was not feasible. The product must be considered in the definition of the trade‐off or compromise of properties to obtain overall satisfactory performance. Such an optimization was carried out and the results are reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1493–1499, 2005