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In this study, flexible CA/PANI films, consisting of polyaniline (PANI) and cellulose acetate (CA), were created via a solution cast production process. Then, these films were irradiated using of handmade cold cathode ion device with argon fluence of 2x1017, 4x1017, and 6x1017 ions/cm2. The SRIM program was used to investigate the ion penetration depth, ion distribution in the composite and the energy stopping loss. Moreover, the FTIR technique was used to identify the changes of the treated CA/PANI. The UV-Vis technique was used to show the impact of argon beam on the optical characteristics of CA/PANI composite film. The oscillation energy (E0) dropped from 8.88 for CA/PANI to 7.83, 6.42, and 5.19 eV after exposed to 2x1017, 4x1017, and 6x1017 ions/cm2. The results showed that the ion altered the optical characteristics of the CA/PANI samples, which allow for applied these irradiated CA/PANI films in optoelectronic devices.

Friction stir processing (FSP) is a modern manufacturing strategy for improving the surface characteristics of materials by modifying their surface via localized plastic deformation. This research focuses on optimization process parameters for tungsten carbide-reinforced 6061 aluminum alloy surface composite using FSP. The effect of the process parameters including tool rotational speed, transverse feed, number of passes, and tungsten carbide particles volume fractions, on ultimate tensile strength (UTS) and grain size of fabricated AA6061/WC surface nanocomposites are investigated. For four factors and three levels, the L27 Taguchi technique is used to formulate the experimental design. The analysis of variance (ANOVA) is used to determine the significance and the percentage contribution of each parameter. The desirability approach is used to optimize the process parameters in terms of tensile strength and average grain size. The results indicate that the proper selection of FSP parameters results in a homogeneous distribution of the WC particles throughout the matrix thereby producing a defect-free AA6061/WC nanocomposite without voids. Also, the severe plastic deformation and heat generation during FSP causes the breaking of coarse particles, WC particles, elimination of porous holes and creates an ultrafine grain-sized structure via dynamic recrystallization. Furthermore, it was concluded that the transverse feed is the most significant factor for ultimate tensile strength with 40.1% contribution whereas the number of passes is the most significant factor for grain size with a 34.7% contribution. The optimum combination of the current process parameters is found to be 1800 rpm rotation speed, 120 mm/min transverse feed, 4.3636% volume fraction, and 3- pass for optimum values of UTS and grain size. The surface composite developed in this work is considered appropriate material for applications requiring lightweight and improved surface properties, such as aerospace, automotive, marine, defense and transportation industries.

PVA/PANI/Ag composite materials made of silver (Ag), polyaniline (PANI), and polyvinyl alcohol (PVA) are prepared for applied in electrical devices. The structure of PVA/PANI/Ag composites was analyzed using XRD, which indicating the samples were successfully synthesized. The crystallite size of AgNPs changed from 12.1 nm to 16 nm by increasing the Ag content from 3 to 6% in the PVA/PANI blend. Moreover, in temperature range 293–353 K, the impacts of PANI as well as AgNPs on the conductivities, permittivity, as well as energy density of PVA were investigated. The conductivity of the films was enhanced with higher frequency due to charge carrier mobility. Furthermore, the density is increased from 1.96 × 10−6J m−3at 20 °C for PVA to 2.7 × 10−6for PVA/PANI/Ag. These results show the prepared PVA/PANI/AgNPs can applied in in a wide range of electronic technologies like batteries, electronic circuits, as well as super capacitors.

In this work, PVA polymeric sheets were irradiated utilizing a homemade ion beam cold cathode source for use in optoelectronics applications. The PVA films were exposed to hydrogen beams with fluence range 8 × 1017to 24 × 1017ions.cm−2. The structural and functional group characteristics of pure and treated PVA films were investigated using XRD and FTIR methods, which confirmed the success fabrication of the PVA films. In frequency of 102to 5 × 106Hz, the conductivity, electrical impedance, and dielectric modulus of untreated and treated samples were determined. The dielectric characteristics of PVA films exhibit a significant modification when subjected to a hydrogen beam. Additionally, after being exposed to 16 × 1017ions, the dielectric constant ε′ improved from 0.0078 for un-irradiated PVA to 0.0395, and conductivity changed from 8.87 × 10−11S cm−1to 3.32 × 10−10S cm−1. Moreover, the relaxation time for PVA is reduced from 28.4 × 10−5s to 8.98 × 10−5s for 8 × 1017ions.cm−2and to 3.5 × 10−5s for 24 × 1017ions.cm−2. The present study extends the potential use of the treated PVA films to a broader range of fields, including microelectronics.

Spinel ion-exchange materials, composed of CaO–MgO–Al2O3ternary systems were prepared via sol–gel reactions followed by sintering at different temperatures. Ca3MgAl4O10, Ca3Al2O6, CaMg2Al16O27, Ca2Mg2Al26O45, corundum, periclase, and monoxide lime were detected at room temperature, while CaAl2O4and MgAl2O4spinels were ascertained at 1,200–1,400 and 1,725–1,900°C, respectively. They were characterized using scanning electron microscopy, X-ray diffraction, X-ray fluorescence, FTIR, DTA–TGA, N2-gas adsorption, and laser diffraction particle size analyzer. We proved that they are chemically and thermally stable in their face-centered array spinel configurations with different surface, morphological, and topographical structures. They were used for removal of 134Cs+, 60Co2+, and 152−154Eu3+from waste solutions; preliminary kinetic and pH were investigated. Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Harkins–Jura, and Halsey isothermal prototypes were applied to describe the equilibria between adsorbed phase metal ions and those in solution at different concentrations. The adsorption of 134Cs+, 60Co2+, and 152−154Eu3+was critically affected by temperatures and ambient pH; spontaneous and exothermic nature of adsorption was found at specific pH values, beyond which the adsorption is restricted. The mechanism of adsorption was found to be chemical reaction combined with ion exchange rather than pure ion exchange.

AbstractSpinel ion-exchange materials, composed of CaO–MgO–Al2O3ternary systems were prepared via sol–gel reactions followed by sintering at different temperatures. Ca3MgAl4O10, Ca3Al2O6, CaMg2Al16O27, Ca2Mg2Al26O45, corundum, periclase, and monoxide lime were detected at room temperature, while CaAl2O4and MgAl2O4spinels were ascertained at 1,200–1,400 and 1,725–1,900°C, respectively. They were characterized using scanning electron microscopy, X-ray diffraction, X-ray fluorescence, FTIR, DTA–TGA, N2-gas adsorption, and laser diffraction particle size analyzer. We proved that they are chemically and thermally stable in their face-centered array spinel configurations with different surface, morphological, and topographical structures. They were used for removal of 134Cs+, 60Co2+, and 152−154Eu3+from waste solutions; preliminary kinetic and pH were investigated. Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Harkins–Jura, and Halsey isothermal prototypes were applied to describe the equilibria between adsorbed phase metal ions and those in solution at different concentrations. The adsorption of 134Cs+, 60Co2+, and 152−154Eu3+was critically affected by temperatures and ambient pH; spontaneous and exothermic nature of adsorption was found at specific pH values, beyond which the adsorption is restricted. The mechanism of adsorption was found to be chemical reaction combined with ion exchange rather than pure ion exchange.

Friction stir processing (FSP) is a solid-state microstructural modification technique that has recently become an effective tool to refine microstructures and improve the mechanical properties of metals. In the current study, optimization of FSP parameters, including tool rotational speed, transverse feed, number of passes, and tungsten carbide (WC) nanoparticle volume fractions on mechanical and wear properties of the fabricated AA6061/WC nanocomposite was studied. Optical microscopy and scanning electron microscopy are used for microstructural observations. The process parameters are optimized using the Taguchi technique for single responses towards microhardness and weight loss and the Desirability approach for both responses. The percentage contribution of process parameters is estimated using analysis of variance. The microstructure observation shows that the proper selection of FSP parameters leads to a homogeneous dispersion of the WC particles throughout the matrix, thereby producing a defect-free AA6061/WC nanocomposite without voids. Also, the severe plastic deformation and heat generation during FSP cause the breaking of coarse particles, WC particles, and porous holes and create an ultrafine grain-sized structure via dynamic recrystallization. The results indicated that the microhardness value of the processed composite was found to be 144 VHN, which is 39.81% higher than that of the base metal. Also, the weight loss of all samples decreased as compared to the base metal. Also, it can be observed that the number of passes is the most significant factor for microhardness, with a 40.1% contribution, and for minimum weight loss, the volume fraction is the most significant factor, with a 56.94% contribution. The optimum process parameter combination was found to be 1800 rpm rotation speed, 120 mm/min of transverse feed, 6% volume fraction, and 3 passes that resulted in obtaining optimum values for micro hardness and weight loss. The surface composite developed in this research is considered a suitable material for applications demanding lightweight and enhanced surface properties, including automotive, aerospace, marine, defense, and transportation industries.

The spectrophotometric determination of pure U(IV) or U(VI) ions in solution with Arsenazo I is greatly dependant on the pH of the solutions. The experimental conditions for the differential estimation of the different oxidation states of U ions, in the same sample, using Arsenazo I have been identified and implemented. The results showed that the applied method is rather rapid and accurate.

The thermal decomposition of some Ni(II)-carboxylate-imidazole complexes in a nitrogen atmosphere was studied non-isothermally. From the non-isothermal thermoanalytical data, it was found that these complexes decompose through a stepwise release of imidazole molecules and/or CO ones forming unstable intermediates which produce metal oxide or the metal as a final decomposition product. TG in conjunction with DTG were used to evaluate the kinetic and thermodynamic parameters of the decomposition reaction. The kinetic studies were performed employing a computer-oriented kinetic analysis of each set of W-Tdata obtained under constant heating rate. The diffusion processes are the decisive mechanisms for the decomposition. The values of ΔE, A, ΔH, ΔSand ΔGfor activation were calculated for the complexes and correlated to variation in their structure.

ABSTRACTA rapid, simple, accurate and specific spectrophotometric procedure for analysis of multi-component mixtures and for assessment of drug stability in pharmaceutical products has been described. The proposed method relies on the application of the spectrophotometric full spectrum quantification (FSQ) software to overcome severe spectral overlap and to permit measurement of the individual components in mixtures with satisfactory degree of accuracy and precision. The potential of FSQ software for multicomponent analysis was elucidated by analyzing complex mixtures of highly overlapping spectra (aspirin/caffeine/salicylic acid) and mixtures of structurally similar compounds (cephalexin/ cephradine) and (ceftriaxone/ ceftazidime /cefotaxime). Furthermore, the robustness of the FSQ for stability studies was assessed by analyzing chloramphenicol in presence of its alkali-induced degradation products and famotidine in presence of its acid-induced degradation products. The validity of FSQ software for multicomponent analysis and stability studies was evaluated by comparing the results with those of HPLC methods. Statistical analysis indicated that the FSQ and HPLC data were consistent, however the FSQ method is faster, easier and more reliable.

A simple and sensitive spectrophotometric method is described for the assay of some tranquillizers and antidepressants, namely, chlorpromazine, imipramine, amitriptyline and chlorprothexine. The method was based on the interaction of these drugs as n-electron donors with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as -acceptor to give a highly coloured radical anion which exhibits maximum absorption at 460 nm. The radical anion was proved by electron spin resonance measurements. The proposed method has been successfully applied for the determination of the examined drugs in tablets. The assay results were in accord with the pharmacopoeial results.

A stability-indicating HPLC analytical method has been developed for the determination of the H2-receptor antagonist, famotidine in the presence of its degradation products. the method utilizes reversed phase chromatography with UV detection and internal calibration techniques. the mobile phase was comprised of 84% ammonium acetate buffer (pH 2.9) and 16% acetonitrile and pumped at a flow rate of 1.5 ml/min. Quantitation was performed by measuring the peak height ratio of drug to internal standard (salicylic acid). the limit of famotidine detection was determined to be 10 ng (0.4 ug/ml) with a signal to noise ratio of 3:1. Within day coefficient of variation of the method was 2.22% (2.5 g/ml) and 0.82% (10 g/ml). Between day coefficient of variation based on the slopes of daily prepared standard curves was 4.70%. the developed method was used to determine the drug content of famotidine tablets. Further, it was used to investigate the kinetics of degradation of the drug in an acidic solution.

A rapid second-derivative spectrophotometric assay procedure has been described for the determination of some benzenoid drugs in pharmaceutical dosage forms. Spectral interference from formulation excipients in simple uv spectrophotometric methods has been eliminated by the application of the proposed method. The different assay parameters, linearity and precision of the method have been assessed. The assay results obtained for eight batches of the pharmaceutical formulations of these drugs are in accord with the declared amounts. The high specificity, ease and simplicity offered by second-derivative spectrophotometry permit unit dose assay of these formulations.

Abstract: The various aspects of valency stabilization of polyvalent ions during gamma-radiolysis have been further investigated. Ce(IV) ions, which are normally reduced in their aqueous solution, were found to be stabilized for increasing periods of time when they were irradiated in the presence of increasing amounts of bromate ions. It was found that the addition of about fifteen times excess of bromate ions to a 10–3 N Ce(IV) solution stabilized the cerium ions in the tetravalent state for about 120 hours during irradiation at a dose rate of 336 Gy/h. Increasing the amount of bromate used resulted in a subsequent increase in the protection time. It has been also noted that while bromate ions protected Ce(IV) in solution, the latter ions showed a clear protective effect on the bromate used, i.e., there is a mutual protective effect. The probable mechanisms, conditions and limitations of the protection process have been discussed. Based on the data obtained in the present work, it has been suggested that the protection of Ce(IV) ions by bromate ions in aqueous solutions during gamma-radiolysis is very probably due to the preferential interaction of bromate with the reducing radiolysis products of water which are capable of reducing Ce(IV) to Ce(III).

Nasopharyngeal carcinoma (NPC) is a malignancy which is consistently associated with the Epstein-Barr virus (EBV). The structure of the EBV genome in NPC suggests that NPC is a clonal proliferation of epithelial cells which emerges after EBV infection. The disease develops with high incidence in specific populations in discrete geographic locations, implicating possible genetic or environmental cofactors. Mutations of the p53 gene are among the most frequent genetic changes found in a large variety of human tumors. Mutations in p53 have been shown to abrogate the suppressor function of wild-type p53 and thus contribute to the transformed phenotype. To determine if mutation in p53 participates in the development of the malignant clone in NPC, the structure and sequence of p53 in 42 primary, metastatic, and nude mouse-passaged NPC specimens was analyzed. A high frequency (6 of 9) of mutations was detected in the nude mouse-passaged tumors, while only 2 of 15 metastatic and 0 of the 18 primary tumors harbored mutant p53. The p53 mutations included single-point mutations and more extensive changes such as frame shifts, deletion, duplication, or complete loss of coding sequences. These data indicate that alterations of the p53 gene are unlikely to be involved in the initial genetic events leading to the clonal outgrowth in NPC. However, although it is a rare NPC which can be established in nude mice, this growth advantage appears to be conferred on tumors bearing a mutant p53.

Abstract: Polyvalent ions are very sensitive to gamma irradiation in aqueous solutions. The present work is a part of a more comprehensive study dealing with the stabilization of certain oxidation states of some polyvalent ions during their gamma irradiation in aqueous systems. Sulphite ions, being well known reducing agents has been used for stabilizing Fe(II) ions in aqueous solutions during gamma radiolysis. Fe(II) ions in solution are known to be readily oxidized by gamma radiations in such a way that a 10–3N solution decays completely in about 2 hours at a dose rate 310 Gy/hr. In presence of an excess of sulphite ions it was found that Fe(II) ions were stabilized for extended time periods depending on the amount of sulphite ions used. The conditions of stabilization and its limits in the studied case has been identified.

This work examines the release of diclofenac sodium from ethylcellulose (EC) microcapsules made up of different drug to polymer ratios. The release process was found to follow the Higuchi square root equation and not the zero-order or first order equations. However, for drug to polymer ratio of 1:1, a critical time (θ) was reached beyond which the release rate was lower than that predicted on the basis of the Higuchi square root equation. Dissolution experiments in 0.1N HCL revealed that less than 1.5% of the encapsulated drug was released in 6 h. This finding indicates the suitability of the EC microcapsules for enteric-coated preparations. The in vitro release of diclofenac sodium from microcapsules of different drug to polymer ratios was compared with that from a commercial sustained-release product. A distinct similarity between the release profile of the commercial product with that obtained for the 1:2 drug to polymer microcapsules was noted. The in vivo work included determination of the serum drug profile following oral administration of the microcapsules and the commercial product to rabbits. The obtained serum concentration time profile of the EC microcapsules exhibited a sustained-release pattern similar to the commercial product and consistent with the in vitro results.

A rapid, sensitive and specific HPLC assay for the determination of ampicillin in human urine is developed.Ampicillin was directly measured in human urine at 225 nm using a reversed phase column (Synchropack RP-P) and a mobile phase composed of (1:9 methanol-sodium acetate solution, 0.01 M, pH 4). The analysis required no longer than 10 min. Linear correlation between the peak height ratio of ampicillin to cefoxitin sodium (internal standard) and ampicillin concentration in urine over the range 10–100 g ml-1 was obtained. The developed method proved to be advantageous as it monitors ampicillin level in urine. Moreover, the urinary excretion of ampicillin in human subjects after an oral administration of 500 mg ampicillin capsules was established using the proposed method.

The discharging currents in cast-prepared PVDF films are measured under the influence of mechanical and thermal multistresses. Analysis of the experimental data in the framework of the Kohlrausch-Williams-Watt's function is carried out. A linear relationship between the logarithm of the relaaxation time and the applied stress is verified, which is displayed as the mechanical offset stress increases. With the aid of the rate theory and the concept of the free volume, the activation volume , υ*, has been determined and is consistent with the reported value. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 859–864, 1998

In rat pancreatic islets the effects of diamide, which has been shown to decrease islet levels of reduced glutathione (GSH), and of exogenous GSH were investigated on cyclic AMP as increased by glucose, p-chloromercuribenzoate, and aminophylline. In addition the effect of diamide on islet ATP level, low Km and high Km phosphodiesterases was studied.

Burush is a small village in the N Sahelian Zone of the Sudan, whose population are basically sedentary agriculturists. The recurring drought conditions of the last two decades have significantly influenced the local resource base, so that the subsistence of the majority of the households was highly challenged. Nevertheless, the people are still surviving and resisting. The explanation of this resistence can be sought in the endogenous coping mechanisms adopted by the people. One of these mechanisms is migration, especially the seasonal labour migration of the heads and grown-up members of households, which used, even in good years, to be highly integrated in the strategies of survival of the majority of households. However under the recurring crop failures and the growing competition in the seasonal labour opportunities, this seasonal migration is changing gradually into stays of longer duration in the traditional destinations of seasonal labour. On the other hand, the male members of households are actively involved in migration of long duration, especially into the urban centres. Yet, the constributions of these migrant members to the subsistence of their households are limited, because of the rising costs of living in uurban centres as compared with the incomes. The rehabilitation of Burush lies obviously in the development of long-term strategies which aim at strengthening the endogenous resilience mechanisms.

The cationic resin of polyacrylamide-acrylic acid "pAM-AA" was prepared by gamma radiation-induced polymerization of acrylic acid "AA" in presence of polyacrylamide "pAM" using a template polymerization technique. The product materials were characterized by powder x-ray diffraction, and infrared spectra.The ion-exchange capacity for Cu2+, Co2+, Cs+ ions decreases with increasing the hydrogen ion concentration. The ion selectivity decreases in the order Cu >2+ Co >2+ Cs+.The effect of gamma radiation on the exchange capacity, distribution coefficients and the chemical stability of the resin has been investigated. The capacity of the resin for Cu2+ decreases with the absorbed doses. In addition, the amount of Cu2+ ion released to the solution from the solid phase increases below pH<4, while at pH>4 the release of Cu2+ ion has vanished.

A family of mRNAs that are transcribed rightward through the BamHI A fragment have been detected in C15, a nasopharyngeal carcinoma (NPC) which has been passaged in nude mice. Northern (RNA) blot hybridizations indicate that these RNAs are also expressed in three other NPCs which have been established in nude mice and in an NPC obtained at biopsy. Moreover, hybridization in situ detected transcription from BamHI A in 12 NPCs and 1 Epstein-Barr virus (EBV)-containing carcinoma of the parotid gland. In each case, transcription was detected in all of the malignant epithelial cells. Transcription was not detected in two cases of EBV-positive lymphoma biopsies by in situ hybridization nor in latently infected EBV-positive lymphoblastoid cell lines by Northern blot hybridization. The consistent transcription of these sequences in latently infected epithelial malignancy but not in lymphoid cells suggests that this viral function is associated with latent EBV infection of epithelial cells. Sequence analysis of a cDNA synthesized from the C15 tumor, representing the 3' end of BamHI A messenger RNA, revealed an open reading frame (ORF). Translation of this ORF in vitro produced several peptides that were immunoprecipitated with antisera from patients with NPC. The detection of antibodies to the protein encoded by the ORF present in the BamHI A cDNA indicates that BamHI A encodes a protein which is expressed in vivo and is antigenic.

It has been suggested that the islet thiol redox status plays a role in the regulation of ß-cell sensitivity in response to insulin secretagogues. Employing the isolated perfused rat pancreas, the effect of reduced glutathione (1 mM) and L-cysteine (5 mM) on insulin release induced by tolbutamide (0.2 mg/ml), glucose (5.6 and 11.1 mM) and tolbutamide (0.1 mg/ml) in the presence of 5.6 mM glucose was studied.

Abstract: The distribution coefficient of sulphide, sulphite, sulphate and thiosulphate anions between different concentrations of aqueous alkali metal chloride solutions and the anion exchanger Dowex 1X8 is studied. The obtained distribution deportment of these anions is explained in the light of water-water, anion-cation and ion-ion interactions as well as the different tendencies of the alkali ions to hydration. Based on the separation factors encountered between adjacent anions, a chromatographic method is adopted for isolation of the sulphur anions by gradient elution. This method is further compared with the chromatographic procedures so far reported for separation of the investigated anions.

Abstract: The kinetics of the exchange of sulphate and chloride ions on the strongly basic anion exchanger Dowex 1X8, of different particle diameters is investigated. The diffusion coefficient values are calculated by two diferent methods, discussed in the light of the processes governing the exchange reactions encountered, and found to be mainly controlled by particle diffusion. The distribution behaviour of sulphate, sulphite, thiosulphate and sulphide between aqueous KCl solutions of different concentrations and a number of selected anion exchange resins is studied. The data are explained on the premises of the different interactions involved in both aqueous and resineous phases. The effect of the alkali metal chloride molarities in the aqueous phase (LiCl, NaCl and KCl) on the exchange behaviour of the different S-anions is also investigated. The results are interpreted in the light of the water—water interaction and the competition for hydration between the alkali metal cations and the exchanged S-anions.

The effect of absorbed dose on the absorption spectra of arsenazo-1 solutions at different concentrations and different pH,s was investigated. Increase of absorbed dose was found to decrease absorption at characteristic peaks. Decolouration yields (G-values) were calculated for the different solutions. The radiolysis of arsenazo-1 solution was also investigated in presence of varying concentrations of methyl alcohol. Using competition kinetics, degradation mechanism was discussed.

A comprehensive study was carried out to examine and evaluate the feasibility of radiation sterilization of cephradine antibiotic in the solid dry state. Absorbed gamma ray doses in the range of 5-25 kGy caused a dose-dependent loss of bactericidal activity. Moreover, radiation caused a dose-dependent degradation of the antibiotic and decrease in cephradine content due to radiation conversion to cephalexin. The former deleterious effect was detected spectrophotometrically and confirmed by high-performance liquid chromatography (HPLC). The latter effect was detected by NMR spectroscopy and by HPLC. The study revealed a noticeable change in the tint of the irradiated powdered drug which is dose-dependent and clearly remarkable at high radiation doses.

Solid 1:1 CT complexes formed between some S-alkyl-N-aryldithiocarbamates and π-electron acceptors (2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetracyanoethylene (TCNE), chloranil (CHL)) are synthesized and characterized. Spectral characteristics and stability of the complexes are investigated and discussed in terms of donor molecular structure, π-acceptor electron affinity, and solvent polarity. It is deduced that the complexes are mainly of the n-π type where the ground state wave function can be described primarily by the non-bonding structure. Ionization potentials of the donors are estimated from the CT transition energies of their complexes. Charge-transfer-Komplexe aus S-Alkyl-N-aryldithiocarbamaten und π-Elektronenakzeptoren (2,3-Dichlor-5,6-dicyano-1,4-benzochinon (DDQ), Tetracyanoethylen (TCNE) und Chloranil (CHL); stöchiometrisches Verhältnis: 1:1) wurden hergestellt und charakterisiert. Die spektroskopischen Eigenschaften und die Stabilitäten der Verbindungen wurden untersucht und werden im Zusammenhang mit Parametern wie Struktur, π-Elektronenakzeptoraffinität und Lösungsmittelpolarität diskutiert. Es zeigt sich, daß die Komplexe hauptsächlich dem n-π-Typ angehören, in dem die Wellenfunktion des Grundzustands vorwiegend durch eine nichtbindende Struktur beschrieben werden kann. Die Ionisationspotentiale der Donatoren werden aus den charge-transfer-Übergangsenergien ihrer Komplexe abgeschätzt.

Epstein-Barr virus DNA was analyzed from specimens of hairy leukoplakia, an oral lesion that occurs in patients infected with the human immunodeficiency virus. The simultaneous presence of both type 1 and type 2 Epstein-Barr virus was demonstrated by Southern blot analysis and polymerase chain reaction assay. Restriction fragment length polymorphisms in the BamHI WYH region and in clones of the EcoRI C region suggested the presence of multiple strains of type 1 and type 2 viruses. The demonstration of multiple variably sized BamHI H fragments on Southern blot analysis and cloning of the EBNA-2 gene coding region also suggested the presence of multiple viral strains or variants coinfecting hairy leukoplakia. Recombination of the viral genome in and around the EBNA-2 gene apparently generated viral variants that replicated efficiently, one of which appeared to increase in abundance in a lesion over time. These data indicate that hairy leukoplakia involves coinfection with multiple strains of replicating Epstein-Barr virus and the endogenous generation of viral variants, some of which have mutations of the EBNA-2 gene.

TheK-conversion coefficients of seven low energy transitions (∼100–400 keV) in182W following the decay of182Ta have been determined by the NPG method using the newly reported γ-ray intensities measured by Ge(Li) detectors. The results are compared with theoretical values deduced from the tabulations of Rose, Sliv and Band, and Pauli. The weak peak corresponding to theK-conversion line of the 351.3 keV transition could be observed in accordance with the previous investigations, however the existance of the previously reported 146.3 keV transition could not be confirmed. Also theK-conversion line of the recently reported 110.4 transition could not be observed.

Increased risk for non-Kodgkin's lymphoma (NHL) may be associated with exposures to pesticides and certain chronic viral infections, including hepatitis C virus (HCV). To study the possible association of agricultural pesticides with NHL in a region with high rates of chronic HCV, we conducted a case-control study in Egypt to assess viral and environmental risk factors for this malignancy.