Intrazeolite phototopotaxy. EXAFS analysis of precursor 8{W(CO)6}-Na56Y and photooxidation products 16(WO3)-Na56Y and 28(WO3)-Na56Y

The intrazeolite photooxidation chemistry of alpha-cage encapsulated hexacarbonyltungsten(0) in Na56Y with O2, denoted n{W(CO)6}-Na56Y/O2/hv, which has previously been shown to provide a novel synthetic pathway to alpha-cage located tungsten(VI) oxide, denoted n(WO3)-Na56Y, is now the subject of an extended X-ray absorption fine structure (EXAFS) analysis. The EXAFS data of a precursor 8{W(CO)6}Na56Y, which contains on average one W(CO)6 per alpha-cage shows that the W(CO)6 guest maintains its structural integrity with only minor observable perturbations of the skeletal WC and ligand CO bonds compared to those found for the same molecule in the free state. The EXAFS analysis results for the photoxidation products 16(WO3)-Na56Y and 28(WO3)-Na56Y are very similar and display the presence of two terminal tungsten-oxygen bonds (1.75-1.77 angstrom) and two bridging tungsten-oxide bonds (1.94-1.95 angstrom), together with a short distance to a second tungsten (3.24-3.30 angstrom). This bond length and coordination number information for n = 16 and 28 samples is best interpreted in terms of the formation of a single kind of tungsten trioxide dimer unit (WO3)2, most likely interacting with extraframework Na+ cations, denoted ZONa...O2W(mu-O)2WO2...NaOZ. In conjunction with earlier chemical and spectroscopic information on this system, the EXAFS data support the contention that 16(WO3)-Na56Y contains a uniform array of single size and shape tungsten (VI) oxide dimers (WO3)2 housed in the 13-angstrom supercages of the zeolite Y host. The sequential addition of WO3 units to the 16(WO3)-Na56Y sample appears to increase the (WO3)2 dimer population, causing a buildup of alpha-cage encapsulated dimers-of-dimers {(WO3)2}2 rather than further cluster growth to trimers (WO3)2 and/or tetramers (WO3)4

Intrazeolite metal carbonyl topotaxy. A comprehensive structural and spectroscopic study of intrazeolite Group VI metal hexacarbonyls and subcarbonyls

This paper focuses attention on the intrazeolite anchoring, thermal decarbonylation, ligand exchange, and addition chemistry of M(CO)6-M'56Y, where M = Cr, Mo, W; M' = H, Li, Na, K, Rb, Cs. The key points to emerge from this study include the following. (i) M(CO)6-M'56Y samples have the hexacarbonylmetal(O) molecule associated with two alpha-cage extraframework cations (or Bronsted protons), via the oxygen end of two trans bonded carbonyls with a saturation loading of 2M(CO)6/alpha-cage. (ii) M(CO)6-M'56Y samples have the hexacarbonylmetal(O) guest confined to the internal surface of the zeolite with a homogeneous distribution throughout the zeolite crystals. (iii) A Mo and Rb EXAFS structure analysis of 8{Mo(CO)6}-Rb56Y shows that the alpha-cage encapsulated Mo(CO)6 guest maintains its structural integrity, with some evidence for anchoring via extraframework Rb+ cations. (iv) A rapid C-13O intrazeolite ligand exchange occurs M(12CO)6-M '56Y to yield M(12CO)m(13CO)6-m-M'56Y, the extent of which depends on the 13CO loading. (v) M(CO)3-M'56Y can be cleanly generated via the mild vacuum thermal decarbonylation of M(CO)6-M56Y, the tricarbonyl stoichiometry of which is unequivocally established from its observed and calculated diagnostic M(12CO)n(13CO)3-n-M'56Y vibrational isotope pattern and from EXAFS structural data. (vi) Intrazeolite ractions of M(CO)3-M'56Y with large and small arenes, trienes, and phosphines cleanly yield the respective intrazeolite six-coordinate complexes (shown to be identical with the products of direct impregnation of the latter complexes), thereby supporting the tricarbonylmetal(0) assignment as well as pinpointing the location of the M(CO)3-M'56Y tricarbonylmetal(0) fragment on the internal surface of the zeolite. (vii) Cation effects in the mid/far-IR, EXAFS data, and optical reflectance spectra indicate that the supercage-confined M(CO)3-M'56Y moiety is anchored to an oxygen framework site rather than to an extrawork cation site via the metal or oxygens of the carbonyls. (viii) The tricarbonyl fragments show C(s) and C3-upsilon symmetry depending on the choice of M and M' which can be rationalized in terms of a second-order Jahn-Teller effect. (ix) EXAFS data for the mild thermal decomposition of Mo(CO)3-Rb56Y demonstrates the formation of molybdenum atoms statistically distributed in the zeolite lattice

Komunikasi Pendek Koleksine Matoda Dari Sulawesi

Sulawesi merupakan lokasi yang menarik untuk penelitian karena jenis-jenis faunanya merupakan peralihan antara fauna Australia dan Asia (Joachim I & Williams WD. 1974. Introduction to Zoogeography.The Macmillan. 110 pp.).Di daerah ini ada beberapa kawasan Taman Nasional yang kaya akan keanekaragaman floradan fauna (Anonim. 1996. Keanekaragaman hayati di Indonesia.Kantor Menteri Negara Lingkungan Hidup dan Konsorsium Nasional untuk Pelestarian Hutan dan Alam Indonesia, Jakarta)

Finite Size Effects and Cooperativity in a Model Diatomic Supercooled Liquid

We use large scale molecular dynamics simulations to investigate the relation between cooperativity and size e ects in a simple diatomic supercooled liquid. We nd that below a characteristic temperature the transport properties depend on the size of the simulation box. is e ect then increases upon decreasing the temperature. For the model molecules constituting our liquid, the smaller box corresponds to the larger di usion coe cient. us, the size e ects increase the di usion of the liquid with our molecules in opposition with previous results concerning silica and atomic so molecules. As a result, the temperature dependence of the di usion coe cient tends to an Arrhenius law for smaller boxes in our simulations. is result is in agreement with a cooperativity origin of non-Arrhenius behavior and size e ects in fragile supercooled liquids, as a small box cuto cooperative motions thus inducing a constant activation energy. To investigate that picture further we then study the size dependence of cooperative motions in our model liquid.

Jenis-jenis Tikus Dan Cacing Parasitnya Di DAS Sekampung, Lampung

Di Indonesia ada ±150 jenis tikus (Kadarsan& Boeadl 1975),namun baru beberapa jenis yang sudah diteliti kandungan cacing parasitnya (Kadarsan 1968, Brown et al. 1975, Carney & Stafford 1979).Padahal tikus dapat berperanan sebagai penyebar penyakit yang disebabkan cacing; kasus penyakit radang selaput otak yang diduga disebabkan cacing Angiostrongylus cantonensis dilaporkan pada pasien rumah sakit Kisaran, Sumatera Utara (Carney et al 1974) dan epidemi skistosomiasis pernah melanda penduduk Lindu, Sulawesi Tengah (Clarke et al. 1974).Mengingat pentingnya peranan tikus sebagai penyebar penyakit cacing pada manusia,dan karena kekayaan fauna cacing di Indonesia belum banyak diketahui maka suatu penelitian dilaksanakan di Dacrah Aliran Sungai Sekampung,Lampung

Acute-on-chronic Liver Failure: MELD Score 30-day Mortality Predictability and Etiology in a Pakistani Population

Background: Cirrhosis is a pathological condition that ultimately leads to liver failure. Acute on chronic liver failure (ACLF) has a high short term mortality rate. Viral hepatitis is the most common cause of liver failure in our local population. We carried out this study to identity the 30-day mortality and etiology of patients presenting with ACLF using Model for End-Stage Liver Disease (MELD) score predictability. Methodology: This was a descriptive case series, conducted at Sheikh Zayed Hospital, Lahore, Pakistan from January 31, 2018 to July 30, 2018. One hundred and eighty five patients who met the inclusion criteria were enrolled using 95% confidence level and 4% margin of error. Data was entered and analyzed with SPSS version 23.0. Numerical variables including age was presented by Mean ± S.D. Categorical variables i.e. gender, etiology of acute-on-chronic liver failure and 30-day mortality were presented by frequency and percentage. Data was stratified for age, gender, duration of chronic liver disease and MELD grade to address the effect modifiers. Post-stratification chi-square test was calculated using 95% significance (p≤0.05). Results: Majority of the enrolled patients were male (74.6%) while only 25.4% of the patients were female. One hundred and thirty patients (70.3%) had underlying viral hepatitis while twelve patients (6.5%) and forty three patients (23.2%) presented with alcoholic liver disease and drug-induced ACLF, respectively. Eighty patients (43.2%) died within 30 days of admission.The 30-day mortality with respect to MELD grade was statistically significant (p<0.001) with the highest mortality noted in grade-IV and thirty five patients (43.8%) dying within 30 days of admission (p<0.001). Grade-II and III MELD scores also contributed to the 30-day mortality with twenty three patients (28.8%) and nineteen patients (23.8%) dying within 30 days of admission (p<0.001). Conclusion: MELD scores are able to accurately predict the short-term mortality in patients with ACLF and viral hepatitis was the most common etiology in our population. Early detection and use of appropriate prognostic models may alleviate mortality and morbidity in paitents with ACLF

Doping and band-gap engineering of an intrazeolite tungsten(VI) oxide supralattice

New results are presented concerning the topotactic self-assembly, n-type doping and band-gap engineering of an intrazeolite tungsten(VI) oxide supralattice n(W03)-Na56Y, where 0 < η < 32, built-up of single size and shape (W03)2 dimers. In particular it has been found that the oxygen content of these dimers can be quantitatively adjusted by means of a thermal vacuum induced reversible reductive-elimination oxidative-addition of dioxygen. This provides access to new n(W03.x)-Na56Y materials (0 < χ ^ 1.0) in which the oxygen content, structural properties and electronic architecture of the dimers are changed. In this way one can precisely control the oxidation state, degree of η-doping and band-filling of a tungsten(VI) oxide supralattice through an approach which can be considered akin to, but distinct in detail to, that found in the Magneli crystallographic shear phases of non-stoichiometric bulk W03.x . Another discovery concerns the ability to alter local electrostatic fields experienced by the tungsten(VI) oxide moieties housed in the 13Ä supercages of 16(W03)-M36Y, by varying the ionic potential of the constituent supercage M + cations across the alkali metal series. This method provides the first opportunity to fine-tune the band-gap of a tungsten(VI) oxide supralattice. Α miniband electronic description is advanced as a qualitative first attempt to understand the origin of the above effects. The implications of these discoveries are that cluster size, composition and intrinsic electrostatic field effects can be used to "chemically manipulate" (engineer) the doping and band architecture of intrazeolite supralattices of possible interest in quantum electronics and nonlinear optics

Pola Kandungan Parasit Pada Tkus-tikus Di Kebun Raya Bogor

S. KADARSAN, E. PURWANINGSIH, S. HARTINI, I.BUDIARTI & A. SAIM 1986. The pattern of parasite infestation on rats at the Bogor Botanical Garden.Berita Biologi 3(4): 173 - 177. Three species of rats namely Rattus exulans, R. r. diardi and R. tiomanicus inhabiting the Bogor Botanical Garden were investigated with respect to their ectoand endoparasite fauna.All three species were infested with Laelaps nutalli, Echinolaelaps echidninus (Acarina); Hoplopleura pacifica and Polyplax reclinata (Anoplura); Xenopsylla cheopis (Siphoriaptera);Hydatigera taeniaefortnis and Viktorokara sp.(Helminth).Additional parasites were Poecilochinis sp., Polyplax spinulosa and Beaveria sp.,a new and yet to be described Troglotrematid Trematode found only R.tiomanicus.The rate of infestation is in part dependent on the age and sex of the host which is seemingly associated with the mobility and food searching capability of the host Time may play an additional role as well

Rapid Assessment on Biodiversity in Logged Forest of Tesso Nilo, Riau Province, Sumatra

Tesso Nilo area which is located at Riau province covers an area of 188.00 ha. Recently, it is famous because of asharply increased in encroachment activities for forest conversion, especially for oil palm plantations and villagesites. It was conducted in logged forest around Segati river, Toro river, Mamahan river and Sawan river in June2003. The results showed that the area had the high richness of plant species which was indicated by the high valueof Mennhenick index. Records from the 1 ha studied plot identified a total of 360 species included 165 genera and57 families with 215 tree species 305 sapling species. Some important tree species which were included in the RedList of IUCN were ‘gaharu’ (Aquilaria malaccensis), ‘ramin’ (Gonystylus bancanus), Shorea spp. and Dipterocarpusspp. The local community utilized 83 species of medicinal plants and 4 species of toxic plants for fishing. The totalnumber of recorded bird species was 114 species represented 29% of the total Sumatran bird species. The mostimportant bird species were the Wrinkled Hornbill (Aceros corrugatus), Crestless Fireback (Lophuraerythrophthalma), Crested Fireback (Lophura ignita) and Hooked-billed Bulbul (Setornis criniger). The total numberof recorded mammal species was 34 species or 16.5% of 206 species of Sumatran mammals. The most importantmammal species included Sumatran tiger (Panthera tigris sumatrae), Sumatran elephant (Elephas maximussumatrensis), the Sun bear (Helarctos malayanus) and three species of primates: Hylobates agilis, Presbytis femoralisand Macaca nemestrina. The herpetofauna contained 15 reptile species and 18 amphibian species. The mostimportant herpetofauna was the endangered False Gharial (Tomistoma schlegelii) and the vulnerable Common Softshelledturtle (Amyda cartilaginea). The number of recorded fish species was 50 represented 18% of the totalSumatran fish species (272 species). The important fish species were Breinsteinea sp. and Chaca bankanensis whichwere unique and rare. Since insects are the largest group of animal, this study only focused on beetles. Theidentified beetles were classified into 644 species and 34 families. The important beetles were the Longhorn beetles(Cerambycidae) and the Scarab beetles (Scarabaeidae).The small mammal parasites consisted of ectoparasites whichwere categorized into 14 species and endoparasites which were categorized into 2 orders and 3 species

Synthesis and Spectroscopic Study of Pentacarbonyl(η2-tetracyanoethylene) Metal(0) Complexes of the Group 6B Elements

Pentacarbonyl (n2-tetracyanoethylene) metal(O) com plexes o f chrom ium , m olybdenum and tung sten have b een synthesized by the photochem ical reaction o f hexacarbonyl metal(O) with te tra cyanoethylene in tolu en e at room tem perature. TTie com plexes w ere purified by chrom atography and recrystallization, and characterized by UV- visible, IR and 13C N M R spectroscopy. T etra cyanoethylene is sym m etrically bonded to the M (C O )5 unit through its c a rb o n -c a rb o n double bond as an ^ 2-ligand. T he spectral data are dis cussed in term s of the m e ta l—»ligand tc inter action