Henkisyys, hyvinvointi, yksilöllisyys ja sosiaalisuus Helsingin Astanga Joogakoulussa

Astangajooga perustuu intialaisen Sri K. Pattabhi Joisin (1915-2009) opetukseen, ja siitä on viime vuosina tullut eräs suosituimmista ja kansainvälisesti laajimmalle levinneistä modernin joogan muodoista. Joogaa voidaan pitää yleisnimityksenä Intian uskontojen piirissä muotoutuneille askeettisille soteriologisille opeille. Käsitteellä moderni jooga kuitenkin viitataan sellaisiin intialaisesta joogatraditiosta tehtyihin tulkintoihin, jotka ovat syntyneet länsimaalaisten ja länsimaisen kulttuurin vaikutuspiirissä olleiden intialaisten toimesta viimeisen n. 150 vuoden aikana. Vaikka varhainen jooga olikin kiinteä osa intialaista uskonnollisuutta, modernin joogan suhde uskonnollis-filosofisiin juuriinsa on vähemmän yksiselitteinen. Tämä on havaittavissa myös Astangajoogan tapauksessa. Tutkielmani käsittelee suomalaisten Astangajoogan harjoittajien käsityksiä joogan merkityksistä. Ensisijaisena aineistonani toimivat kymmenen Helsingin Astanga Joogakoulussa harjoittelevan Sri K. Pattabhi Joisin opetusperinteeseen pohjautuvan Astangajoogan harjoittajan haastattelut. Astangajoogan harjoittajilta ei Helsingin Astanga Joogakoulussa vaadita sitoutumista mihinkään oppeihin tai elämäntapavalintoihin. Painopiste on voimakkaasti liikunnallisen ?sana-harjoittelun säännöllisessä ylläpitämisessä. Kuitenkin myös Astangajoogan menetelmissä ja Helsingin Astanga Joogakoulun opetuksessa on piirteitä, joiden perusteella Astangajoogan ei voida sanoa olevan täysin riippumaton sen taustalla vaikuttavasta uskonnollis-filosofisesta perinteestä. Tutkimuskysymykseni ovat 1) liittävätkö Astangajoogan harjoittajat joogaan uskonnollisiksi tai henkisiksi tulkittavia merkityksiä, ja 2) millaisia nämä merkitykset ovat ja miten ne liittyvät harjoituksen muihin ulottuvuuksiin (esim. terveydellinen, sosiaalinen, psykologinen). Tältä pohjalta toivon 3) pystyväni tarkastelemaan, miten Astanga asettuu nykypäivän uskonnolliseen kenttään, ja mitä sen harjoittajien näkemykset mahdollisesti kertovat uskonnon asemasta ja luonteesta nykyaikana. Analyysimetodinani käytän aineistolähtöistä sisällönanalyysia. Vertaan analyysissa esiin nousseita teemoja Paul Heelasin holistisen henkisyyden teoriaan. Holistisella henkisyydellä Heelas tarkoittaa subjektia ja subjektiivista kokemusta painottavaa, ulkoisista instituutioista riippumatonta uskonnollisuutta, jossa ruumiillisuudella, terveydellä ja sosiaalisilla suhteilla on tärkeä asema. Haastatteluaineiston analyysin pohjalta totean, että Astangajoogalla on usein harjoittajilleen henkisenä pidetty ulottuvuus. Haastattelemieni Astangajoogan harjoittajien henkisyyttä määrittelevät sisäisyys, omaehtoisuus ja holistisuus. Astangajoogasta etsittiin mm. vaihtoehtoa dogmaattiseksi koetulle kristinuskolle. Astangajoogan harjoittamista ei kuitenkaan voida pitää uushindulaisuuden muotona, vaan sitä pidettiin ”uskontovapaana henkisyytenä”. Analyysin perusteella voidaankin todeta, että haastateltujen esittämät näkemykset vastasivat yleisesti varsin hyvin Paul Heelasin holistisen henkisyyden teorian keskeisiä teemoja. Kuitenkin myös merkittäviä poikkeuksia tästä esiintyi. Ne antavat aihetta mahdolliselle jatkotutkimukselle.

The role of His-134, -147, and -150 residues in subunit assembly, cofactor binding, and catalysis of sheep liver cytosolic serine hydroxymethyltransferase

In an attempt to unravel the role of conserved histidine residues in the structure-function of sheep liver cytosolic serine hydroxymethyltransferase (SHMT), three site-specific mutants (H134N, H147N, and H150N) were constructed and expressed, H134N and H147N SHMTs had K-m values for L-serine, L-allo-threonine and beta-phenylserine similar to that of wild type enzyme, although the k(cat) values were markedly decreased, H134N SHMT was obtained in a dimeric form with only 6% of bound pyridoxal 5'-phosphate (PLP) compared with the wild type enzyme, Increasing concentrations of PLP (up to 500 mu M) enhanced the enzyme activity without changing its oligomeric structure, indicating that His-134 may be involved in dimer-dimer interactions, H147N SHMT was obtained in a tetrameric form but with very little PLP (3%) bound to it, suggesting that this residue was probably involved in cofactor binding, Unlike the wild type enzyme, the cofactor could be easily removed by dialysis from H147N SHMT, and the apoenzyme thus formed was present predominantly in the dimeric form, indicating that PLP binding is at the dimer-dimer interface, H150N SHMT was obtained in a tetrameric form with bound PLP, However, the mutant had very little enzyme activity (<2%). The k(cat)/K-m values for L-serine, L-allo-threonine and beta-phenylserine were 80-, 56-, and SS-fold less compared with wild type enzyme, Unlike the wild type enzyme, it failed to form the characteristic quinonoid intermediate and was unable to carry out the exchange of 2-S proton from glycine in the presence of H-4-folate. However, it could form an external aldimine with serine and glycine, The wild type and the mutant enzyme had similar K-d values for serine and glycine, These results suggest that His-150 may be the base that abstracts the alpha-proton of the substrate, leading to formation of the quinonoid intermediate in the reaction catalyzed by SHMT.

Molecular epidemiology of human rhinoviruses

The first part of this work investigates the molecular epidemiology of a human enterovirus (HEV), echovirus 30 (E-30). This project is part of a series of studies performed in our research team analyzing the molecular epidemiology of HEV-B viruses. A total of 129 virus strains had been isolated in different parts of Europe. The sequence analysis was performed in three different genomic regions: 420 nucleotides (nt) in the VP4/VP2 capsid protein coding region, the entire VP1 capsid protein coding gene of 876 nt, and 150 nt in the VP1/2A junction region. The analysis revealed a succession of dominant sublineages within a major genotype. The temporally earlier genotypes had been replaced by a genetically homogenous lineage that has been circulating in Europe since the late 1970s. The same genotype was found by other research groups in North America and Australia. Globally, other cocirculating genetic lineages also exist. The prevalence of a dominant genotype makes E-30 different from other previously studied HEVs, such as polioviruses and coxsackieviruses B4 and B5, for which several coexisting genetic lineages have been reported. The second part of this work deals with molecular epidemiology of human rhinoviruses (HRVs). A total of 61 field isolates were studied in the 420-nt stretch in the capsid coding region of VP4/VP2. The isolates were collected from children under two years of age in Tampere, Finland. Sequences from the clinical isolates clustered in the two previously known phylogenetic clades. Seasonal clustering was found. Also, several distinct serotype-like clusters were found to co-circulate during the same epidemic season. Reappearance of a cluster after disappearing for a season was observed. The molecular epidemiology of the analyzed strains turned out to be complex, and we decided to continue our studies of HRV. Only five previously published complete genome sequences of HRV prototype strains were available for analysis. Therefore, all designated HRV prototype strains (n=102) were sequenced in the VP4/VP2 region, and the possibility of genetic typing of HRV was evaluated. Seventy-six of the 102 prototype strains clustered in HRV genetic group A (HRV-A) and 25 in group B (HRV-B). Serotype 87 clustered separately from other HRVs with HEV species D. The field strains of HRV represented as many as 19 different genotypes, as judged with an approximate demarcation of a 20% nt difference in the VP4/VP2 region. The interserotypic differences of HRV were generally similar to those reported between different HEV serotypes (i.e. about 20%), but smaller differences, less than 10%, were also observed. Because some HRV serotypes are genetically so closely related, we suggest that the genetic typing be performed using the criterion "the closest prototype strain". This study is the first systematic genetic characterization of all known HRV prototype strains, providing a further taxonomic proposal for classification of HRV. We proposed to divide the genus Human rhinoviruses into HRV-A and HRV-B. The final part of the work comprises a phylogenetic analysis of a subset (48) of HRV prototype strains and field isolates (12) in the nonstructural part of the genome coding for the RNA-dependent RNA polymerase (3D). The proposed division of the HRV strains in the species HRV-A and HRV-B was also supported by 3D region. HRV-B clustered closer to HEV species B, C, and also to polioviruses than to HRV-A. Intraspecies variation within both HRV-A and HRV-B was greater in the 3D coding region than in the VP4/VP2 coding region, in contrast to HEV. Moreover, the diversity of HRV in 3D exceeded that of HEV. One group of HRV-A, designated HRV-A', formed a separate cluster outside other HRV-A in the 3D region. It formed a cluster also in the capsid region, but located within HRV-A. This may reflect a different evolutionary history of distinct genomic regions among HRV-A. Furthermore, the tree topology within HRV-A in the 3D region differed from that in the VP4/VP2, suggesting possible recombination events in the evolution of the strains. No conflicting phylogenies were observed in any of the 12 field isolates. Possible recombination was further studied using the Similarity and Bootscanning analyses of the complete genome sequences of HRV available in public databases. Evidence for recombination among HRV-A was found, as HRV2 and HRV39 showed higher similarity in the nonstructural part of the genome. Whether HRV2 and HRV39 strains - and perhaps also some other HRV-A strains not yet completely sequenced - are recombinants remains to be determined.

Postmenopausal hot flushes, vascular health and hormone therapy

Vasomotor hot flushes are complained of by approximately 75% of postmenopausal women, but their frequency and severity show great individual variation. Hot flushes have been present in women attending observational studies showing cardiovascular benefit associated with hormone therapy use, whereas they have been absent or very mild in randomized hormone therapy trials showing cardiovascular harm. Therefore, if hot flushes are a factor connected with vascular health, they could perhaps be one explanation for the divergence of cardiovascular data in observational versus randomized studies. For the present study 150 healthy, recently postmenopausal women showing a large variation in hot flushes were studied in regard to cardiovascular health by way of pulse wave analysis, ambulatory blood pressure and several biochemical vascular markers. In addition, the possible impact of hot flushes on outcomes of hormone therapy was studied. This study shows that women with severe hot flushes exhibit a greater vasodilatory reactivity as assessed by pulse wave analysis than do women without vasomotor symptoms. This can be seen as a hot flush-related vascular benefit. Although severe night-time hot flushes seem to be accompanied by transient increases in blood pressure and heart rate, the diurnal blood pressure and heart rate profiles show no significant differences between women without and with mild, moderate or severe hot flushes. The levels of vascular markers, such as lipids, lipoproteins, C-reactive protein and sex hormone-binding globulin show no association with hot flush status. In the 6-month hormone therapy trial the women were classified as having either tolerable or intolerable hot flushes. These groups were treated in a randomized order with transdermal estradiol gel, oral estradiol alone or in combination with medroxyprogesterone acetate, or with placebo. In women with only tolerable hot flushes, oral estradiol leads to a reduced vasodilatory response and increases in 24-hour and daytime blood pressures as compared to women with intolerable hot flushes receiving the same therapy. No such effects were observed with the other treatment regimes or in women with intolerable hot flushes. The responses of vascular biomarkers to hormone therapy are unaffected by hot flush status. In conclusion, hot flush status contributes to cardiovascular health before and during hormone therapy. Severe hot flushes are associated with an increased vasodilatory, and thus, a beneficial vascular status. Oral estradiol leads to vasoconstrictive changes and increases in blood pressure, and thus to possible vascular harm, but only in women whose hot flushes are so mild that they would probably not lead to the initiation of hormone therapy in clinical practice. Healthy, recently postmenopausal women with moderate to severe hot flushes should be given the opportunity to use hormone therapy alleviate hot flushes, and if estrogen is prescribed for indications other than for the control of hot flushes, transdermal route of administration should be favored.

Studies on diamond-like carbon and novel diamond-like carbon polymer hybrid coatings deposited with filtered pulsed arc discharge method

The main obstacle for the application of high quality diamond-like carbon (DLC) coatings has been the lack of adhesion to the substrate as the coating thickness is increased. The aim of this study was to improve the filtered pulsed arc discharge (FPAD) method. With this method it is possible to achieve high DLC coating thicknesses necessary for practical applications. The energy of the carbon ions was measured with an optoelectronic time-of-flight method. An in situ cathode polishing system used for stabilizing the process yield and the carbon ion energies is presented. Simultaneously the quality of the coatings can be controlled. To optimise the quality of the deposition process a simple, fast and inexpensive method using silicon wafers as test substrates was developed. This method was used for evaluating the suitability of a simplified arc-discharge set-up for the deposition of the adhesion layer of DLC coatings. A whole new group of materials discovered by our research group, the diamond-like carbon polymer hybrid (DLC-p-h) coatings, is also presented. The parent polymers used in these novel coatings were polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE). The energy of the plasma ions was found to increase when the anode-cathode distance and the arc voltage were increased. A constant deposition rate for continuous coating runs was obtained with an in situ cathode polishing system. The novel DLC-p-h coatings were found to be water and oil repellent and harder than any polymers. The lowest sliding angle ever measured from a solid surface, 0.15 ± 0.03°, was measured on a DLC-PDMS-h coating. In the FPAD system carbon ions can be accelerated to high energies (≈ 1 keV) necessary for the optimal adhesion (the substrate is broken in the adhesion and quality test) of ultra thick (up to 200 µm) DLC coatings by increasing the anode-cathode distance and using high voltages (up to 4 kV). An excellent adhesion can also be obtained with the simplified arc-discharge device. To maintain high process yield (5µm/h over a surface area of 150 cm2) and to stabilize the carbon ion energies and the high quality (sp3 fraction up to 85%) of the resulting coating, an in situ cathode polishing system must be used. DLC-PDMS-h coating is the superior candidate coating material for anti-soiling applications where also hardness is required.

Genistein and 17β-estradiol fatty acid esters in blood and adipose tissue and the structure-related antioxidant activity of estrogens on lipoproteins

Soy-derived phytoestrogen genistein and 17β-estradiol (E2), the principal endogenous estrogen in women, are also potent antioxidants protecting LDL and HDL lipoproteins against oxidation. This protection is enhanced by esterification with fatty acids, resulting in lipophilic molecules that accumulate in lipoproteins or fatty tissues. The aims were to investigate, whether genistein becomes esterified with fatty acids in human plasma accumulating in lipoproteins, and to develop a method for their quantitation; to study the antioxidant activity of different natural and synthetic estrogens in LDL and HDL; and to determine the E2 esters in visceral and subcutaneous fat in late pregnancy and in pre- and postmenopause. Human plasma was incubated with [3H]genistein and its esters were analyzed from lipoprotein fractions. Time-resolved fluoroimmunoassay (TR-FIA) was used to quantitate genistein esters in monkey plasma after subcutaneous and oral administration. The E2 esters in women s serum and adipose tissue were also quantitated using TR-FIA. The antioxidant activity of estrogen derivatives (n=43) on LDL and HDL was assessed by monitoring the copper induced formation of conjugated dienes. Human plasma was shown to produce lipoprotein-bound genistein fatty acid esters, providing a possible explanation for the previously reported increased oxidation resistance of LDL particles during intake of soybean phytoestrogens. Genistein esters were introduced into blood by subcutaneous administration. The antioxidant effect of estrogens on lipoproteins is highly structure-dependent. LDL and HDL were protected against oxidation by many unesterified, yet lipophilic derivatives. The strongest antioxidants had an unsubstituted A-ring phenolic hydroxyl group with one or two adjacent methoxy groups. E2 ester levels were high during late pregnancy. The median concentration of E2 esters in pregnancy serum was 0.42 nmol/l (n=13) and in pre- (n=8) and postmenopause (n=6) 0.07 and 0.06 nmol/l, respectively. In pregnancy visceral fat the concentration of E2 esters was 4.24 nmol/l and in pre- and postmenopause 0.82 and 0.74 nmol/l. The results from subcutaneous fat were similar. In serum and fat during pregnancy, E2 esters constituted about 0.5 and 10% of the free E2. In non-pregnant women most of the E2 in fat was esterified (the ester/free ratio 150 - 490%). In postmenopause, E2 levels in fat highly exceeded those in serum, the majority being esterified. The pathways for fatty acid esterification of steroid hormones are found in organisms ranging from invertebrates to vertebrates. The evolutionary preservation and relative abundance of E2 esters, especially in fat tissue, suggest a biological function, most likely in providing a readily available source of E2. The body s own estrogen reservoir could be used as a source of E2 by pharmacologically regulating the E2 esterification or hydrolysis.

R3Mn1.5CuV0.5O9 (R = Y, Ho, Er, Tm, Yb and Lu) and Lu3Mn3-3xCu2xVxO9: New noncentro symmetric oxides related to YMnO3

We report formation of new noncentrosymmetric oxides of the formula, R3Mn1.5CuV0.5O9 for R = Y, Ho, Er, Tm, Yb and Lu, possessing the hexagonal RMnO3 (space group P6(3)cm) structure. These oxides could be regarded as the x = 0.5 members of a general series R3Mn3-3xCu2xVxO9. Investigation of the Lu-Mn-Cu-V-O system reveals the existence of isostructural solid solution series, Lu3Mn3-3xCu2xVxO9 for 0 < x <= 0.75. Magnetic and dielectric properties of the oxides are consistent with a random distribution of Mn3+, Cu2+ and V5+ atoms that preserve the noncentrosymmetric RMnO3 structure. (c) 2006 Elsevier Ltd. All rights reserved.

"Innokas punikki". Hyvinkään punakaartilaisnaiset sisällissodan jälkiselvittelyissä 1918.

Hyvinkääläiset työläisnaiset ottivat vuoden 1918 sisällissotaan osaa punakaartin riveissä ruoanlaittajina, sairaanhoitajina sekä asetta kantaneina sotilaina. Valkokaartia tukemaan saapuneet saksalaissotilaat saavuttivat Hyvinkään huhtikuun 20. päivä, ja pitäjä valloitettiin. Osa hyvinkääläisnaisista oli tässä vaiheessa siirtynyt jo pohjoisemmille rintamille. Valkoiset etenivät kuitenkin voittoisasti kohti pohjoista, ja suurin osa hyvinkääläisnaisista oli antautunut 1. toukokuuta mennessä. Tämä tutkimus tarkastelee Hyvinkään punakaartilaisnaisiin kohdistuneita kuulustelututkimuksia ja toimenpiteitä sisällissodan jälkiselvittelyissä, jotka alkoivat huhtikuussa ja jatkuivat vuoden loppuun saakka. Samalla tuon esiin runsaasti uutta tietoa Hyvinkään punakaartilaisnaisten toimista sisällissodassa sekä heidän taustoistaan. Tärkeimpiä lähteitä tutkimuksessani ovat erilaiset Kansallisarkistossa säilytettävät oikeusasiakirjat: Hyvinkään pitäjän kenttäoikeuksien pöytäkirjat, viralliset esitutkintapöytäkirjat sekä valtiorikosoikeuksien ja valtiorikosylioikeuden aktit. Lisäksi olen etsinyt tietoa sodassa ja sen jälkiselvittelyissä surmansa saaneista punaisista hyvinkääläisnaisista. Tässä tärkeimpinä lähteinäni ovat olleet Suomen Sotasurmat 1914–1922 -projektin nimitiedosto sekä valkokaartin kirjanpidosta löytyneet vangitsemistiedot. Olen hyödyntänyt suuren tietomäärän käsittelyssä tilastollisia menetelmiä. Tarkastelen naisia kuitenkin paljon myös yksilötasolla, sillä juuri yksilötarinat rikastuttavat paikallishistoriallista tutkimusta. Tutkimukseni perusteella punaisiksi luokiteltuja hyvinkääläisnaisia menehtyi sisällissodan jälkiselvittelyissä 27 – heistä suurin osa Lahden ja Hämeenlinnan seudulla, missä viimeiset taistelut käytiin. Menehtyneistä naisista moni oli vasta 16–17-vuotias. Myös hyvinkääläisnaisia joutui suurille vankileireille – tässä yhteydessä tarkastelen kahden naisen vankileirimuistelmia. Kotipaikkakunnalla tutkittiin samanaikaisesti kenttäoikeuksissa 64 hyvinkääläisnaista. Kenttäoikeuksien tehtävänä oli kartoittaa punakaartilaisten toimintaa sekä heidän tietojansa paikkakunnalla ja lähiseuduilla tapahtuneista murhista sekä ryöstöistä. Kenttäoikeuksissa kuulustelluista naisista valtaosa vapautettiin lyhyen vankeuden jälkeen. Jälkiselvittelyjen virallisessa vaiheessa 116 hyvinkääläistä punakaartilaisnaista joutui kuulusteluihin. Heistä vajaa puolet oli toiminut sodan aikana erilaisissa huoltotehtävissä mm. punakaartin ruokalassa. 25 naista oli epäiltynä Hyvinkäällä huhtikuussa perustetussa aseellisessa naiskaartissa toimimisesta. Loput olivat toimineet punaisten hallinnossa tai sairaanhoitotehtävissä kotipaikkakunnalla ja rintamilla. Kuulustelujen perusteella 81 naista sai vuoden 1918 jälkipuoliskolla syytteen valtiorikosoikeudessa; heistä suurin osa avunannosta valtiopetokseen. Tutkimukseni kattaa näin kaikkiaan noin 150 hyvinkääläistä punakaartilaisnaista. Tutkimukseni valottaa heidän toimintaansa sodan aikana sekä arvioi rankaisutoimenpiteiden motiiveja. Tutkimukseni mukaan asetta kantaneisiin naisiin suhtauduttiin jälkiselvittelyissä keskimäärin hyvin ankarasti. Muiden punakaartilaisnaisten osalta rankaisutoimenpiteissä ei ollut yhtenäistä linjaa. Perunankuorinta punakaartin ruokalassa saattoi olla tuomittava rikos siinä missä kaartilaisten matkoilla liikkuminen ja ryöstetyn tavaran kätkeminen.

Change detection and controlling forest information using multi-temporal Landsat TM imagery.

A method was developed for relative radiometric calibration of single multitemporal Landsat TM image, several multitemporal images covering each others, and several multitemporal images covering different geographic locations. The radiometricly calibrated difference images were used for detecting rapid changes on forest stands. The nonparametric Kernel method was applied for change detection. The accuracy of the change detection was estimated by inspecting the image analysis results in field. The change classification was applied for controlling the quality of the continuously updated forest stand information. The aim was to ensure that all the manmade changes and any forest damages were correctly updated including the attribute and stand delineation information. The image analysis results were compared with the registered treatments and the stand information base. The stands with discrepancies between these two information sources were recommended to be field inspected.

Phase relations in the systems Cu–O–R2O3(R = Tm, Lu) and Gibbs energies of formation of Cu2R2O5 compounds

The phase relations in the systems Cu–O–R2O3(R = Tm, Lu) have been determined at 1273 K by X-ray diffraction, optical microscopy and electron probe microanalysis of samples equilibrated in evacuated quartz ampules and in pure oxygen. Only ternary compounds of the type Cu2R2O5 were found to be stable. The standard Gibbs energies of formation of the compounds have been measured using solid-state galvanic cells of the type, Pt|Cu2O + Cu2R2O5+ R2O3‖(Y2O3)ZrO2‖CuO + Cu2O‖Pt in the temperature range 950–1325 K. The standard Gibbs energy changes associated with the formation of Cu2R2O5 compounds from their binary component oxides are: 2CuO(s)+ Tm2O3(s)→Cu2Tm2O5(s), ΔG°=(10400 – 14.0 T/K)± 100 J mol–1, 2CuO(s)+ Lu2O3(s)→Cu2Lu2O5(s), ΔG°=(10210 – 14.4 T/K)± 100 J mol–1 Since the formation is endothermic, the compounds become thermodynamically unstable with respect to component oxides at low temperatures, Cu2Tm2O5 below 743 K and Cu2Lu2O5 below 709 K. When the chemical potential of oxygen over the Cu2R2O5 compounds is lowered, they decompose according to the reaction, 2Cu2R2O5(s)→2R2O3(s)+ 2Cu2O(s)+ O2(g) The equilibrium oxygen potential corresponding to this reaction is obtained from the emf. Oxygen potential diagrams for the Cu–O–R2O3 systems at 1273 K are presented.

Decomposition temperatures of Cu2Ln2O5 (Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds

The equilibrium decomposition temperatures of Cu2Ln2O5 (Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds have been measured using a combined DTA-TGA apparatus under a flowing Ar + O2 gas mixture, in which the partial pressure of oxygen was controlled at 5.0 × 103 Pa. The Cu2Ln2O5 compounds yield Ln2O3 and Cu2O on decomposition. The decomposition temperature increases monotonically with the atomic number of the lanthanide element. This suggests that the stability of the Cu2Ln2O5 compounds with respect to the component binary oxides increases with decreasing radius of the Ln3+ ion.

Thermodynamic properties of Pt5La, Pt5Ce, Pt5Pr, Pt5Tb and Pt5Tm intermetallics

The Gibbs’ energies of formation of Pt5La, Pt5Ce, Pt5Pr, Pt5Tb and Pt5 Tm intermetallic compounds have been determined in the temperature range 870–1100 K using the solid state cell:Ta,M + MF3 /CaF2 /Pt5 M + Pt + MF3 ,TaTaM+MF3CaF2Pt5M+Pt+MF3Ta.The reversible emf of the cell is directly related to the Gibbs’ energy of formation of the Pt5M compound. The results can be summarized by the equations:DGf° á Pt5 La ñ = - 373,150 + 6 ·60 T( ±300 )J mol - 1 DGf° á Pt5 Ce ñ = - 367,070 + 5 ·79 T( ±300 )J mol - 1 DGf° á Pt5 Pr ñ = - 370,540 + 4 ·69 T( ±300 )J mol - 1 DGf° á Pt5 Tb ñ = - 372,280 + 4 ·11 T( ±300 )J mol - 1 DGf° á Pt5 Tm ñ = - 368,230 + 4 ·89 T( ±300 )J mol - 1 Unknown control sequence '\hfill'relative to the low temperature allotropic form of the lanthanide element and solid platinum as standard states The enthalpies of formation of all the Pt5M intermetallic compounds obtained in this study are in good agreement with Miedema’s model. The experimental values are more negative than those calculated using the model. The variation of the thermodynamic properties of Pt5M compounds with atomic number of the lanthanide element is discussed in relation to valence state and molar volume.