Anomalous dielectric behavior of some ferrites

The dielectric behavior of some powdered polycrystalline samples has been studied in the frequency range of 200 Hz–100 kHz. It is shown that the dielectric behavior in these systems below the Curie temperature is not purely relaxational in its character and cannot be described by any of the models of the dielectric relaxation hitherto put forward. It is also shown that ‘‘isolation’’ of the particles in the powder samples plays a very important role. The origin of this abnormality is thought to be due to the mechanical resonance arising out of the magnetostrictive property of the material.

Actuator fault detection and isolation in linear systems

A scheme for the detection and isolation of actuator faults in linear systems is proposed. A bank of unknown input observers is constructed to generate residual signals which will deviate in characteristic ways in the presence of actuator faults. Residual signals are unaffected by the unknown inputs acting on the system and this decreases the false alarm and miss probabilities. The results are illustrated through a simulation study of actuator fault detection and isolation in a pilot plant doubleeffect evaporator.

Purification of goat serum retinol-binding protein and preparation of its antibodies

The method for the purification of goat serum retinol-binding protein consists of DEAE-cellulose chromatography of the serum followed by preparative polyacrylamide disc gel electrophoresis. After electrophoresis, the retinol-binding protein containing zone is identified by the specific fluorescence of retinol. For raising the antibodies, the portion of the gel containing retinol binding protein is homogenized and injected intradermally and intramuscularly to rabbits. The availability of this simple method for the isolation of retinol-binding protein and production of its antibodies enables the development of a radioimmunoassay for this protein.

Detection, epidemiology and host spectrum of cowpox and Borna disease virus infections

Several orthopoxviruses (OPV) and Borna disease virus (BDV) are enveloped, zoonotic viruses with a wide geographical distribution. OPV antibodies cross-react, and former smallpox vaccination has therefore protected human populations from another OPV infection, rodent-borne cowpox virus (CPXV). Cowpox in humans and cats usually manifests as a mild, self-limiting dermatitis and constitutional symptoms, but it can be severe and even life-threatening in the immunocompromised. Classical Borna disease is a progressive meningoencephalomyelitis in horses and sheep known in central Europe for centuries. Nowadays the virus or its close relative infects humans and also several other species in central Europe and elsewhere, but the existence of human Borna disease with its suspected neuropsychiatric symptoms is controversial. The epidemiology of BDV is largely unknown, and the present situation is even more intriguing following the recent detection of several-million-year-old, endogenized BDV genes in primate and various other vertebrate genomes. The aims of this study were to elucidate the importance of CPXV and BDV in Finland and in possible host species, and particularly to 1) establish relevant methods for the detection of CPXV and other OPVs as well as BDV in Finland, 2) determine whether CPXV and BDV exist in Finland, 3) discover how common OPV immunity is in different age groups in Finland, 4) characterize possible disease cases and clarify their epidemiological context, 5) establish the hosts and possible reservoir species of these viruses and their geographical distribution in wild rodents, and 6) elucidate the infection kinetics of BDV in the bank vole. An indirect immunofluorescence assay and avidity measurement were established for the detection, timing and verification of OPV or BDV antibodies in thousands of blood samples from humans, horses, ruminants, lynxes, gallinaceous birds, dogs, cats and rodents. The mostly vaccine-derived OPV seroprevalence was found to decrease gradually according to the year of birth of the sampled human subjects from 100% to 10% in those born after 1977. On the other hand, OPV antibodies indicating natural contact with CPXV or other OPVs were commonly found in domestic and wild animals: the horse, cow, lynx, dog, cat and, with a prevalence occasionally even as high as 92%, in wild rodents, including some previously undetected species and new regions. Antibodies to BDV were detected in humans, horses, a dog, cats, and for the first time in wild rodents, such as bank voles (Myodes glareolus). Because of the controversy within the human Borna disease field, extra verification methods were established for BDV antibody findings: recombinant nucleocapsid and phosphoproteins were produced in Escherichia coli and in a baculovirus system, and peptide arrays were additionally applied. With these verification assays, Finnish human, equine, feline and rodent BDV infections were confirmed. Taken together, wide host spectra were evident for both OPV and BDV infections based on the antibody findings, and OPV infections were found to be geographically broadly distributed. PCR amplification methods were utilised for hundreds of blood and tissue samples. The methods included conventional, nested and real-time PCRs with or without the reverse transcription step and detecting four or two genes of OPVs and BDV, respectively. OPV DNA could be amplified from two human patients and three bank voles, whereas no BDV RNA was detected in naturally infected individuals. Based on the phylogenetic analyses, the Finnish OPV sequences were closely related although not identical to a Russian CPXV isolate, and clearly different from other CPXV strains. Moreover, the Finnish sequences only equalled each other, but the short amplicons obtained from German rodents were identical to monkeypox virus, in addition to German CPXV variants. This reflects the close relationship of all OPVs. In summary, RNA of the Finnish BDV variant could not be detected with the available PCR methods, but OPV DNA infrequently could. The OPV species infecting the patients of this study was proven to be CPXV, which is most probably also responsible for the rodent infections. Multiple cell lines and some newborn rodents were utilised in the isolation of CPXV and BDV from patient and wildlife samples. CPXV could be isolated from a child with severe, generalised cowpox. BDV isolation attempts from rodents were unsuccessful in this study. However, in parallel studies, a transient BDV infection of cells inoculated with equine brain material was detected, and BDV antigens discovered in archival animal brains using established immunohistology. Thus, based on several independent methods, both CPXV and BDV (or a closely related agent) were shown to be present in Finland. Bank voles could be productively infected with BDV. This experimental infection did not result in notable pathological findings or symptoms, despite the intense spread of the virus in the central and peripheral nervous system. Infected voles commonly excreted the virus in urine and faeces, which emphasises their possible role as a BDV reservoir. Moreover, BDV RNA was regularly reverse transcribed into DNA in bank voles, which was detected by amplifying DNA by PCR without reverse transcription, and verified with nuclease treatments. This finding indicates that BDV genes could be endogenized during an acute infection. Although further transmission studies are needed, this experimental infection demonstrated that the bank vole can function as a potential BDV reservoir. In summary, multiple methods were established and applied in large panels to detect two zoonoses novel to Finland: cowpox virus and Borna disease virus. Moreover, new information was obtained on their geographical distribution, host spectrum, epidemiology and infection kinetics.

Plant aspartate transcarbamylase: An affinity chromatographic method for the purification of the enzyme from germinated seedlings

A simple and rapid affinity chromatographic method for the isolation of aspartate transcarbamylase from germinated seedlings of mung bean (Phaseolus aureus) was developed. A partially purified preparation of the enzyme was chromatographed on an affinity column containing aspartate linked to CNBr-activated Sepharose 4B. Aspartate transcarbamylase was specifically eluted from the column with 10 mImage aspartate or 0.5 Image KCl. The enzyme migrated as a single sharp band during disc electrophoresis at pH 8.6 on polyacrylamide gels. Electrophoresis of the sodium dodecyl sulfate-treated enzyme showed two distinct protein bands, suggesting that the mung bean aspartate transcarbamylase was made up of nonidentical subunits. Like the enzyme purified by conventional procedures, this enzyme preparation also exhibited positive homotropic interactions with carbamyl phosphate and negative heterotropic interactions with UMP. This method was extended to the purification of aspartate transcarbamylase from Lathyrus sativus, Eleucine coracona, and Trigonella foenum graecum.

DNA damage recognition in the normal epithelium of human prostate and seminal vesicles

Prostate cancer is one of the most prevalent cancer types in men. The development of prostate tumors is known to require androgen exposure, and several pathways governing cell growth are deregulated in prostate tumorigenesis. Recent genetic studies have revealed that complex gene fusions and copy - number alterations are frequent in prostate cancer, a unique feature among solid tumors. These chromosomal aberrations are though to arise as a consequence of faulty repair of DNA double strand breaks (DSB). Most repair mechanisms have been studied in detail in cancer cell lines, but how DNA damage is detected and repaired in normal differentiated human cells has not been widely addressed. The events leading to the gene fusions in prostate cancer are under rigorous studies, as they not only shed light on the basic pathobiologic mechanisms but may also produce molecular targets for prostate cancer treatment and prevention. Prostate and seminal vesicles are part of the male reproductive system. They share similar structure and function but differ dramatically in their cancer incidence. Approximately fifty primary seminal vesicle carcinomas have been reported worldwide. Surprisingly, only little is known on why seminal vesicles are resistant to neoplastic changes. As both tissues are androgen dependent, it is a mystery that androgen signaling would only lead to tumors in prostate tissue. In this work, we set up novel ex vivo human tissue culture models of prostate and seminal vesicles, and used them to study how DNA damage is recognized in normal epithelium. One of the major DNA - damage inducible pathways, mediated by the ATM kinase, was robustly activated in all main cell types of both tissues. Interestingly, we discovered that secretory epithelial cells had less histone variant H2A.X and after DNA damage lower levels of H2AX were phosphorylated on serine 139 (γH2AX) than in basal or stromal cells. γH2AX has been considered essential for efficient DSB repair, but as there were no significant differences in the γH2AX levels between the two tissues, it seems more likely that the role of γH2AX is less important in postmitotic cells. We also gained insight into the regulation of p53, an important transcription factor that protects genomic integrity via multiple mechanisms, in human tissues. DSBs did not lead to a pronounced activation of p53, but treatments causing transcriptional stress, on the other hand, were able to launch a notable p53 response in both tissue types. In general, ex vivo culturing of human tissues provided unique means to study differentiated cells in their relevant tissue context, and is suited for testing novel therapeutic drugs before clinical trials. In order to study how prostate and seminal vesicle epithelial cells are able to activate DNA damage induced cell cycle checkpoints, we used primary cultures of prostate and seminal vesicle epithelial cells. To our knowledge, we are the first to report isolation of human primary seminal vesicle cells. Surprisingly, human prostate epithelial cells did not activate cell cycle checkpoints after DSBs in part due to low levels of Wee1A, a kinase regulating CDK activity, while primary seminal vesicle epithelial cells possessed proficient cell cycle checkpoints and expressed high levels of Wee1A. Similarly, seminal vesicle cells showed a distinct activation of the p53 - pathway after DSBs that did not occur in prostate epithelial cells. This indicates that p53 protein function is under different control mechanisms in the two cell types, which together with proficient cell cycle checkpoints may be crucial in protecting seminal vesicles from endogenous and exogenous DNA damaging factors and, as a consequence, from carcinogenesis. These data indicate that two very similar organs of male reproductive system do not respond to DNA damage similarly. The differentiated, non - replicating cells of both tissues were able to recognize DSBs, but under proliferation human prostate epithelial cells had deficient activation of the DNA damage response. This suggests that prostate epithelium is most vulnerable to accumulating genomic aberrations under conditions where it needs to proliferate, for example after inflammatory cellular damage.

Microbial identification by detection of ligation probes on DNA microarray

Microbes in natural and artificial environments as well as in the human body are a key part of the functional properties of these complex systems. The presence or absence of certain microbial taxa is a correlate of functional status like risk of disease or course of metabolic processes of a microbial community. As microbes are highly diverse and mostly notcultivable, molecular markers like gene sequences are a potential basis for detection and identification of key types. The goal of this thesis was to study molecular methods for identification of microbial DNA in order to develop a tool for analysis of environmental and clinical DNA samples. Particular emphasis was placed on specificity of detection which is a major challenge when analyzing complex microbial communities. The approach taken in this study was the application and optimization of enzymatic ligation of DNA probes coupled with microarray read-out for high-throughput microbial profiling. The results show that fungal phylotypes and human papillomavirus genotypes could be accurately identified from pools of PCR amplicons generated from purified sample DNA. Approximately 1 ng/μl of sample DNA was needed for representative PCR amplification as measured by comparisons between clone sequencing and microarray. A minimum of 0,25 amol/μl of PCR amplicons was detectable from amongst 5 ng/μl of background DNA, suggesting that the detection limit of the test comprising of ligation reaction followed by microarray read-out was approximately 0,04%. Detection from sample DNA directly was shown to be feasible with probes forming a circular molecule upon ligation followed by PCR amplification of the probe. In this approach, the minimum detectable relative amount of target genome was found to be 1% of all genomes in the sample as estimated from 454 deep sequencing results. Signal-to-noise of contact printed microarrays could be improved by using an internal microarray hybridization control oligonucleotide probe together with a computational algorithm. The algorithm was based on identification of a bias in the microarray data and correction of the bias as shown by simulated and real data. The results further suggest semiquantitative detection to be possible by ligation detection, allowing estimation of target abundance in a sample. However, in practise, comprehensive sequence information of full length rRNA genes is needed to support probe design with complex samples. This study shows that DNA microarray has the potential for an accurate microbial diagnostic platform to take advantage of increasing sequence data and to replace traditional, less efficient methods that still dominate routine testing in laboratories. The data suggests that ligation reaction based microarray assay can be optimized to a degree that allows good signal-tonoise and semiquantitative detection.

Bioinorganic and medicinal chemistry: aspects of gold(I)-protein complexes

Gold(I)-based drugs have been used successfully for the treatment of rheumatoid arthritis (RA) for several years. Although the exact mechanism of action of these gold(I) drugs for RA has not been clearly established, the interaction of these compounds with mammalian enzymes has been extensively studied. In this paper, we describe the interaction of therapeutic gold(I) compounds with mammalian proteins that contain cysteine (Cys) and selenocysteine (Sec) residues. Owing to the higher affinity of gold(I) towards sulfur and selenium, gold(I) drugs rapidly react with the activated cysteine or selenocysteine residues of the enzymes to form protein-gold(I)-thiolate or protein-gold(I)-selenolate complexes. The formation of stable gold(I)-thiolate/selenolate complexes generally lead to inhibition of the enzyme activity. The gold-thiolate/selenolate complexes undergo extensive ligand exchange reactions with other nucleophiles and such ligand exchange reactions alter the inhibitory effects of gold(I) complexes. Therefore, the effect of gold(I) compounds on the enzymatic activity of cysteine-or selenocysteine-containing proteins may play important roles in RA. The interaction of gold(I) compounds with different enzymes and the biochemical mechanism underlying the inhibition of enzymatic activities may have broad medicinal implications for the treatment of RA.

Metallo-beta-lactamase-Catalyzed Hydrolysis of Cephalosporins: Some Mechanistic Insights into the Effect of Heterocyclic Thiones on Enzyme Activity

The hydrolysis of beta-lactam antibiotics using zinc-containing metallo-beta-lactamases (m beta l) is one of the major bacterial defense systems. These enzymes can catalyze the hydrolysis of a variety of antibiotics including the latest generation of cephalosporins, cephamycins, and imipenem. It is shown in this paper that the cephalosporins having heterocyclic - SR side chains are less prone to m beta l-mediated hydrolysis than the antibiotics that do not have such side chains. This is partly due to the inhibition of enzyme activity by the thione moieties eliminated during hydrolysis. When the enzymatic hydrolysis of oxacillin was carried out in the presence of heterocyclic thiones such as MU, MDT, DMETT, and MMA, the catalytic activity of the enzyme was inhibited significantly by these compounds. Although the heterocyclic - SR moieties eliminated from the beta-lactams upon hydrolysis undergo a rapid tautomerism between thione and thiol forms, these compounds act as thiolate ligands toward zinc(II) ions. The structural characterization of two model tetranuclear zinc(II) thiolate complexes indicates that the -SR side chains eliminated from the antibiotics may interact with the zinc(II) metal center of m beta l through their sulfur atoms.

Peanut agglutinin from callus and cell suspension cultures of Arachis hypogaea L

Synthesis of peanut agglutinin was induced in callus and cell suspension cultures of cotyledons of peanut (Arachis hypogaea L.). The lectin was synthesised in cultures through several passages. Biosynthesis of peanut agglutinin was regulated by the type and concentration of exogenous growth regulators and was positively correlated to the growth of the cultures,indicating that the agglutinin may have a role to play during cell growth. Movement of agglutinin from the cells into the medium not only facilitated easy isolation of the lectin but also provided a clue that it may probably serve as a defence molecule. The synthesized lectin purified from culture, was found to be biologically active, and was found to be comparable with the lectin from seeds, in terms of its electrophoretic mobility.

Role of neutral metabolites in microbial conversion of 3beta-acetoxy-19-hydroxycholest-5-ene into estrone

Biotransformation of 3 beta-acetoxy-19-hydroxycholest-5-ene (19-HCA, 6 g) by Moraxella sp. was studied. Estrone (712 mg) was the major metabolite formed. Minor metabolites identified were 5 alpha-androst-1-en-19-ol-3,17-dione (33 mg), androst-4-en-19-ol-3,17-dione (58 mg), androst-4-en-9 alpha,19-diol-3,17-dione (12 mg), and androstan-19-ol-3,17-dione (1 mg). Acidic metabolites were not formed. Time course experiments on the fermentation of 19-HCA indicated that androst-4-en-19-ol-3,17-dione was the major metabolite formed during the early stages of incubation. However with continuing fermentation its level dropped, with a concomitant increase in estrone. Fermentation of 19-HCA in the presence of specific inhibitors or performing the fermentation for a shorter period (48 h) did not result in the formation of acidic metabolites. Resting-cell experiments carried out with 19-HCA (200 mg) in the presence of alpha,alpha'-bipyridyl led to the isolation of three additional metabolites, viz., cholestan-19-ol-3-one (2 mg), cholest-4-en-19-ol-3-one (10 mg), and cholest-5-en-3 beta,19-diol (12 mg). Similar results were also obtained when n-propanol was used instead of alpha,alpha'-bipyridyl. Resting cells grown on 19-HCA readily converted both 5 alpha-androst-1-en-19-ol-3,17-dione and androst-4-en-19-ol-3,17-dione into estrone. Partially purified 1,2-dehydrogenase from steroid-induced Moraxella cells transformed androst-4-en-19-ol-3,17-dione into estrone and formaldehyde in the presence of phenazine methosulfate, an artificial electron acceptor. These results suggest that the degradation of the hydrocarbon side chain of 19-HCA does not proceed via C-22 phenolic acid intermediates and complete removal of the C-17 side chain takes place prior to the aromatization of the A ring in estrone. The mode of degradation of the sterol side chain appears to be through the fission of the C-17-C-20 bond. On the basis of these observations, a new pathway for the formation of estrone from 19-HCA in Moraxella sp. has been proposed.

New open-framework phosphate and phosphite compounds of gallium

Five new open-framework compounds of gallium have been synthesized by hydrothermal methods and their structures determined by single crystal X-ray diffraction studies. The compounds, C8N4H26]Ga6F4(PO4)(6)], I, C5N3H11]Ga3F2(PO4)(3)]center dot H2O, II, C6N3H19]Ga-4(C2O4)(PO4)(4)(H2PO4)]center dot 2H(2)O, III, Ga2F3(HPO4)(PO4)]center dot 2H(3)O, IV, and C3N2H5](2)Ga-4(H2O)(3)(HPO3)(7)], V, possess three-dimensional structures. All the compounds are formed by the connectivity between the Ga polyhedra and phosphite/phosphate units. The observation of SBU-6 (I and II) and spiro-5 (IV) secondary building units (SBUs) are noteworthy. The flexibility of the formation of gallium phosphate frameworks has been established by the isolation of two related structures (I and II) from the same SBU units but different organic amines. Some of the present structures have close resemblance to the gallium phosphate phases known earlier. The compounds have been characterized by CHN analysis, powder XRD, IR, and TGA. (C) 2011 Elsevier B. V. All rights reserved.

Chelating and bridging bis(diphenylphosphino)aniline complexes of copper(I)

The ligand bis(diphenylphosphino)aniline (dppan) has been shown to be a versatile ligand sporting different coordination modes and geometries as dictated by copper(I) and the counter ion. The molecular structures of its Cu(I) complexes were characterized by X-ray crystallography. The ligand was found in a chelating mode and monomeric complexes were formed when the ligand to copper ratio was 2: 1 and the anion was non-coordinating. However, with thiocyanate as the counter anion, the ligand was found to adopt two different modes, with one ligand chelating and the other acting as a monodentate ligand. With CuX (X = Cl, Br), dppan formed a tetrameric complex when the ligand and metal were reacted in the ratio of 1:1. But reactions containing ligand and metal in the ratios of 1: 2 or 2: 1, resulted in the formation of a mixture of species in solution. Crystallization however, led to the isolation of the tetrameric complex. Variable temperature P-31{H-1} NMR spectra of the isolated tetramers did not show the presence of chelated structures in solution. Tetra-alkylammonium salts were added to solutions of various complexes of dppan and studied by P-31{H-1} NMR to probe the effect of anions on the stability of complexes in solution. The Cu-dppan complexes were robust and did not interconvert with other structures in solution unlike the bis(diphenylphosphino) isopropylamine complexes. (C) 2011 Elsevier B.V. All rights reserved.

Localization induced base isolation in fractionally damped non linear system

In the present article we take up the study of nonlinear localization induced base isolation of a 3 degree of freedom system having cubic nonlinearities under sinusoidal base excitation. The damping forces in the system are described by functions of fractional derivative of the instantaneous displacements, typically linear and quadratic damping are considered here separately. Under the assumption of smallness of certain system parameters and nonlinear terms an approximate estimate of the response at each degree of freedom of the system is obtained by the Method of Multiple Scales approach. We then consider a similar system where the nonlinear terms and certain other parameters are no longer small. Direct numerical simulation is made use of to obtain the amplitude plot in the frequency domain for this case, which helps us to establish the efficacy of this method of base isolation for a broad class of systems. Base isolation obtained this way has no counterpart in the linear theory.

Synthesis, Characterization, and Electronic Structure of New Type of Heterometallic Boride Clusters

The reaction of [Cp*TaCl(4)], 1 (Cp* = eta(5)-C(5)Me(5)), with [LiBH(4)center dot THF] at -78 degrees C, followed by thermolysis in the presence of excess [BH(3)center dot THF], results in the formation of the oxatantalaborane cluster [(Cp*Ta)(2)B(4)H(10)O], 2 in moderate yield. Compound 2 is a notable example of an oxatantalaborane cluster where oxygen is contiguously bound to both the metal and boron. Upon availability of 2, a room temperature reaction was performed with [Fe(2)(CO)(9)], which led to the isolation of [(Cp*Ta)(2)B(2)H(4)O{H(2)Fe(2)(CO)(6)BH} ] 3. Compound 3 is an unusual heterometallic boride cluster in which the [Ta(2)Fe(2)] atoms define a butterfly framework with one boron atom lying in a semi-interstitial position. Likewise, the diselenamolybdaborane, [(Cp*Mo)(2)B(4)H(4)Se(2)], 4 was treated with an excess of [Fe(2)(CO)(9)] to afford the heterometallic boride cluster [(Cp*MoSe)(2)Fe(6)(CO)(13)B(2)(BH)(2)], 5. The cluster core of 5 consists of a cubane [Mo(2)Se(2)Fe(2)B(2)] and a tricapped trigonal prism [Fe(6)B(3)] fused together with four atoms held in common between the two subclusters. In the tricapped trigonal prism subunit, one of the boron atoms is completely encapsulated and bonded to six iron and two boron atoms. Compounds 2, 3, and 5 have been characterized by mass spectrometry, IR, (1)H, (11)B, (13)C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis. The density functional theory calculations yielded geometries that are in close agreement with the observed structures. Furthermore, the calculated (11)B NMR chemical shifts also support the structural characterization of the compounds. Natural bond order analysis and Wiberg bond indices are used to gain insight into the bonding patterns of the observed geometries of 2, 3, and 5.