Atomistic modeling of zeolitic materials

A review with 166 refs. on modeling the structure and properties of the bare zeolitic framework. The topics include modeling methods and interat. potential developmen

Lattice mechanical study of the structure of dodecasil-3C

A recently developed partial charge potential model for SiO2 polymorphs, derived from quantum chem. calcns., was applied to the calcn. of the lattice energy-minimized structure and phys. properties of the low-d. SiO2 crystal Dodecasil-3C. Calcns. were performed using Ewald summations and without symmetry constraints. Results are compared with calcns. using the shell model of Sanders et al. (1983). Best agreement between exptl. and theor. predicted elastic consts. is achieved assuming a triclinic structure. To establish lattice stability, the vibrational frequency spectrum was calcd. For structures with imaginary frequencies, the corresponding at. displacements are used to deform the quasi-stationary geometry. On lattice energy minimization, the deformed structure transforms to a stable energy min. The large anisotropic temp. factors obsd. exptl. are mainly due to static disorder in at. position

Antiviral combination therapy in chronic hepatitis B

An outbreak of parenterally transmitted hepatitis was probably first recorded in 1885 by Lurman who reported the occurrence of jaundice among personnel of a Bremen factory after revaccination against smallpox. Of 1289 individuals vaccinated in one day, 191 developed jaundice 2 to 8 months after administration of glycerinated human lymph preparations. The illness usually began with fatigue,anorexia and gastrointestinal complaints followed by jaundice and often pruritus; it generally lasted a total of 4 to 6 weeks.Personnel vaccinated on another day with another vaccine preparation as well as those who left the job before revaccination were not affected, Comparison of the water supply, domicile, alcohol abuse and vaccine exposure indicated the latter as the probable cause of the outbreak (1,2,3). In 1945 MacCallum postulated that, on the basis of differences in incubation period and mode of transmission, two different agents cause hepatitis: hepatitis A and hepatitis B. He was not able to isolate the infectious agents (4). In 1967 Krugman and Giles confirmed the existence of two types of hepatitis:one with a short and one with a long incubation period (5). In 1965 Blumberg had already discovered an antigen in the serum of an Australian aboriginal which he called 'Australia antigen' (6). In 1968 Prince identified an antigen in the serum of patients with post-transfusion hepatitis, an antigen which he called SH antigen (7). The antigens discovered by Blumberg and Prince were found to be identical and represent the hepatitis B surface antigen. Between 1968 and 1973 the other principal viral antigens <HBeAg,HBcAg) and their antibodies were identified (8,9). The electron microscopy features of the virus were described by Dane in 1970. In the blood of infected patients the large complete virus particle (diameter 42 nm), small 22 nm spherical surface antigen particles and tubular forms (length 100 nm,diameter 22 nm) were found (10). Infection with the hepatitis B virus is characterized not only by production of infectious complete virus particles (Dane particles) but also by an enhanced production of incomplete viral particles made up entirely of HBsAg without HBcAg, DNA-polymerase activity or HBV-DN

Beter laat dan nooit : over de noodzaak tot implementatie van antivirale therapie bij chronische virale hepatitis B en C

Ovaj rad pod nazivom Kineski emitivni turizam i utjecaj na Europsku uniju bavi se gospodarskim, društvenim, političkim i turističkim razvojem Kine te pokazuje turistička kretanja prema Europi. Gospodarska, i djelomično sve otvorenija politika Narodne Republike Kine značajno doprinosi povećanju kineskom emitivnom turizmu. To se odnosi na međunarodni turizam, receptivni turizam i sve veći emitivni turizam u Kini. Pomoću pojednostavljenog ADS (approved destination status) postupka, povećanja obrazovanja i prihoda u kućanstvima, te sve više slobodnog vremena kao i pravo na regulirani odmor, kineskom stanovništvu se sve više omogućuje putovanje izvan granica svoje zemlje. Na temelju analize znanstvene literature, socio-ekonomskih turističkih podataka i uključivanja izvora iz znanstvenih članaka, u ovome se radu prikazuju pokretači turizma,razvoj, politika kao i bitne institucije turističke industrije koje sudjeluju u stvaranju turizma kao takvog

Modeling of structure and vibrational spectra of aluminophosphate AlPO4 5 and its silica analog SSZ 24

In this study, the structural and vibrational properties of the AlPO4 structure AlPO4-5 and the silica structure SSZ-24 are compared. Lattice energy calcns. are done using existing potential parameter sets suitable for silicas and AlPO4's. For the computation of vibrational spectra of silica systems, force consts. derived by Etchepare et al. are used. For AlPO4 spectra simulations, a new force field is presented that is based on a fit on vibrational frequencies of a-berlinite, the AlPO4 analog of a-quartz. Lattice energy calcns. result in a symmetry of AlPO4-5 and SSZ-24 that is lower than derived exptl. A shift of layers is obsd. for both structures when a potential with partial charges is used. These results are indicative for an underestn. of the charges used in the partial charge model. The influence of structure on spectra is shown to be rather weak. The main differences between the spectra of AlPO4-5 and SSZ-24 are due to the interat. force const

A randomised study on the efficacy and safety of an automated Tru-Cut needle for percutaneous liver biopsy

BACKGROUND: We studied whether the theoretical advantages of a spring-loaded liver biopsy needle exist in clinical practice and if so if they are dependent upon the experience of the physician performing the biopsy. METHODS: In a stratified randomised study we enrolled 215 consecutive patients to compare the safety and efficacy of a new automatic biopsy gun (Acecut) with that of a standard Tru-Cut needle. RESULTS: A total of 464 biopsies were performed. The endpoints of the study were number of needle passes needed per patient, tissue yield of each needle pass and post-biopsy complications. The performance of the automatic needle was superior and more consistent with respect to tissue yield compared with the Tru-Cut needle (median yield 100% and 80%, respectively; p < 0.001). The difference was most marked for inexperienced physicians. There was no difference between the two needles in the number of passes needed. More post-biopsy pain and post-biopsy use of analgesics were observed in the automatic needle group (p = 0.04). CONCLUSION: The automatic Tru-Cut needle offers an advantage, particularly for physicians with no or limited experience in liver biopsies. However more post-biopsy pain and post-biopsy use of analgesics were observed in the automatic needle group

Association between a progesterone receptor mutation and hepatitis E sero-positivity in liver transplant recipients

Problem: We investigated if the PROGINS mutation increases the risk of hepatitis E virus (HEV) infection in liver transplant recipients. PROGINS was analyzed through KASP assay; HEV serologies assessed via enzyme-linked immunosorbent assay and multiplex cytokine assays were evaluated in plasma with the ProcartaPlex human immunoassay. Seventy liver transplant recipients were evaluated, of which 23 (33%) were HEV immunoglobuln G (IgG)-positive (HEV+). The frequency of PROGINS in the HEV+ group was 34%, compared with 14% in those that were HEV IgG negative (HEV−). Cytokine measurements in a sub-set of samples from HEV+/PROGINS+ individuals showed decreased plasma levels of monokine induced by gamma interferon, a proliferation-inducing ligand, and stem cell factor, as well as increased levels of eotaxin-3 and interleukin-31 compared with those HEV−/PROGINS− samples. Our findings suggest an association between the PROGINS mutation and seropositivity for HEV in liver transplant recipients with consequent distorted cytokine levels

Lattice-relaxation of zeolites

Quantum-chemical cluster calculations as well as solid-state chemical lattice-calculations indicate that zeolitic SiO2- and AlPO4-structures are flexible structures. The structures reflect the subtle balance of electrostatic and covalent interactions. The different electrostatic interactions lower the symmetry of layered AlPO4-structures compared to that of the corresponding SiO2-compounds. The result is a smaller zeolite-channel dimension for the AlPO4-structure compared to that of the corresponding SiO2-network. Deprotonation of the zeolite-lattice leads to large local changes in geometry that changes acidity compared to that predicted for a non-flexible lattice. Changes in lattice vibrational frequencies are consistent with the theoretically predicted relaxation of the zeolite-lattic