bluuebunny/crossref_metadata_2025 huggingface dataset:
Roles of Ring-Hydroxylating Dioxygenases in Styrene and Benzene Catabolism inRhodococcus jostiiRHA1
Authors: Patrauchan Marianna A. , Florizone Christine , Eapen Shawn , Gómez-Gil Leticia , Sethuraman Bhanu , Fukuda Masao , Davies Julian , Mohn William W. , Eltis Lindsay D.
Published: October 2007

Proteomics and targeted gene disruption were used to investigate the catabolism of benzene, styrene, biphenyl, and ethylbenzene inRhodococcus jostiiRHA1, a well-studied soil bacterium whose potent polychlorinated biphenyl (PCB)-transforming properties are partly due to the presence of the related Bph and Etb pathways. Of 151 identified proteins, 22 Bph/Etb proteins were among the most abundant in biphenyl-, ethylbenzene-, benzene-, and styrene-grown cells. Cells grown on biphenyl, ethylbenzene, or benzene contained both Bph and Etb enzymes and at least two sets of lower Bph pathway enzymes. By contrast, styrene-grown cells contained no Etb enzymes and only one set of lower Bph pathway enzymes. Gene disruption established that biphenyl dioxygenase (BPDO) was essential for growth of RHA1 on benzene or styrene but that ethylbenzene dioxygenase (EBDO) was not required for growth on any of the tested substrates. Moreover, whole-cell assays of the ΔbphAaandetbAa1::cmrA etbAa2::aphIImutants demonstrated that while both dioxygenases preferentially transformed biphenyl, only BPDO transformed styrene. Deletion ofpcaLof the β-ketoadipate pathway disrupted growth on benzene but not other substrates. Thus, styrene and benzene are degraded viameta- andortho-cleavage, respectively. Finally, catalases were more abundant during growth on nonpolar aromatic compounds than on aromatic acids. This suggests that the relaxed specificities of BPDO and EBDO that enable RHA1 to grow on a range of compounds come at the cost of increased uncoupling during the latter's initial transformation. The stress response may augment RHA1's ability to degrade PCBs and other pollutants that induce similar uncoupling.
Phosphoketolase Pathway Dominates in
Lactobacillus reuteri
ATCC 55730 Containing Dual Pathways for Glycolysis
Authors: Årsköld Emma , Lohmeier-Vogel Elke , Cao Rong , Roos Stefan , Rådström Peter , van Niel Ed W. J.
Published: October 2007

Metabolic flux analysis indicated that the heterofermentative
Lactobacillus reuteri
strain ATCC 55730 uses both the Embden-Meyerhof pathway (EMP) and phosphoketolase pathway (PKP) when glucose or sucrose is converted into the three-carbon intermediate stage of glycolysis. In all cases studied, the main flux is through the PKP, while the EMP is used as a shunt. In the exponential growth phase, 70%, 73%, and 84% of the flux goes through the PKP in cells metabolizing (i) glucose plus fructose, (ii) glucose alone, and (iii) sucrose alone, respectively. Analysis of the genome of
L. reuteri
ATCC 55730 confirmed the presence of the genes for both pathways. Further evidence for the simultaneous operation of two central carbon metabolic pathways was found through the detection of fructose-1,6-bisphosphate aldolase, phosphofructokinase, and phosphoglucoisomerase activities and the presence of phosphorylated EMP and PKP intermediates using in vitro
31
P NMR. The maximum specific growth rate and biomass yield obtained on glucose were twice as low as on sucrose. This was the result of low ATP levels being present in glucose-metabolizing cells, although the ATP production flux was as high as in sucrose-metabolizing cells due to a twofold increase of enzyme activities in both glycolytic pathways. Growth performance on glucose could be improved by adding fructose as an external electron acceptor, suggesting that the observed behavior is due to a redox imbalance causing energy starvation.
A New TetR Family Transcriptional Regulator Required for Morphogenesis inStreptomyces coelicolor
Authors: Hillerich Brandan , Westpheling Janet
Published: October 2007

Both morphogenesis and antibiotic production in the streptomycetes are initiated in response to starvation, and these events are coupled. We previously described a transposon-generated mutant inStreptomyces coelicolor, SE293, that resulted in abldstrain that overproduced the antibiotic actinorhodin. The SCO1135 open reading frame identified by the insertion encodes a member of the TetR family of transcriptional regulators. Here we show that a constructed deletion of the SCO1135 open reading frame resulted in the same morphological and antibiotic production phenotype as the insertion mutant. The constructed deletion also resulted in constitutive expression of SCO1135 transcript, as well as that of the gene cluster immediately adjacent to it, SCO1134-1132, which encodes a putative molybdopterin binding complex. A His6-tagged version of the SCO1135 protein product was shown to bind the intergenic region between SCO1135 and SCO1134, which contains the apparent transcription start sites for each gene mapped by primer extension analysis. Increased expression of the SCO1134-1132 transcript in the SCO1135 deletion mutant also resulted in increased expression of xanthine dehydrogenase activity, confirming the predictions about these open reading framed based on protein similarity. We have designated the SCO1134-1142 gene clusterxdhABCand the regulator encoded by SCO1135xdhR. We speculate that the inappropriate expression of xanthine dehydrogenase affects purine salvaging pathways at the onset of development, creating artificially high concentrations of both GTP and ppGpp and perturbing the pathways these molecules participate in for the initiation of morphogenesis and antibiotic production.
The Two Chorismate Mutases from both
Mycobacterium tuberculosis
and
Mycobacterium smegmatis
: Biochemical Analysis and Limited Regulation of Promoter Activity by Aromatic Amino Acids
Authors: Schneider Cristopher Z. , Parish Tanya , Basso Luiz A. , Santos Diógenes S.
Published: October 2007

Chorismate mutase (CM) catalyzes the rearrangement of chorismate to prephenate in the biosynthetic pathway that forms phenylalanine and tyrosine in bacteria, fungi, plants, and apicomplexan parasites. Since this enzyme is absent from mammals, it represents a promising target for the development of new antimycobacterial drugs, which are needed to combat
Mycobacterium tuberculosis
, the causative agent of tuberculosis. Until recently, two putative open reading frames (ORFs), Rv0948c and Rv1885c, showing low sequence similarity to CMs have been described as “conserved hypothetical proteins” in the
M. tuberculosis
genome. However, we and others demonstrated that these ORFs are in fact monofunctional CMs of the AroQ structural class and that they are differentially localized in the mycobacterial cell. Since homologues to the
M. tuberculosis
enzymes are also present in
Mycobacterium smegmatis
, we cloned the coding sequences corresponding to ORFs MSMEG5513 and MSMEG2114 from the latter. The CM activities of both ORFs was determined, as well as their translational start sites. In addition, we analyzed the promoter activities of three
M. tuberculosis
loci related to phenylalanine and tyrosine biosynthesis under a variety of conditions using
M. smegmatis
as a surrogate host. Our results indicate that the
aroQ
(Rv0948c), *
aroQ
(Rv1885c), and
fbpB
(Rv1886c) genes from
M. tuberculosis
are constitutively expressed or subjected to minor regulation by aromatic amino acids levels, especially tryptophan.
Transcriptome Dynamics during the Transition from Anaerobic Photosynthesis to Aerobic Respiration in
Rhodobacter sphaeroides
2.4.1
Authors: Arai Hiroyuki , Roh Jung Hyeob , Kaplan Samuel
Published: October 2007

Rhodobacter sphaeroides
2.4.1 is a facultative photosynthetic anaerobe that grows by anoxygenic photosynthesis under anaerobic-light conditions. Changes in energy generation pathways under photosynthetic and aerobic respiratory conditions are primarily controlled by oxygen tensions. In this study, we performed time series microarray analyses to investigate transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration. Major changes in gene expression profiles occurred in the initial 15 min after the shift from anaerobic-light to aerobic-dark conditions, with changes continuing to occur up to 4 hours postshift. Those genes whose expression levels changed significantly during the time series were grouped into three major classes by clustering analysis. Class I contained genes, such as that for the
aa
3
cytochrome oxidase, whose expression levels increased after the shift. Class II contained genes, such as those for the photosynthetic apparatus and Calvin cycle enzymes, whose expression levels decreased after the shift. Class III contained genes whose expression levels temporarily increased during the time series. Many genes for metabolism and transport of carbohydrates or lipids were significantly induced early during the transition, suggesting that those endogenous compounds were initially utilized as carbon sources. Oxidation of those compounds might also be required for maintenance of redox homeostasis after exposure to oxygen. Genes for the repair of protein and sulfur groups and uptake of ferric iron were temporarily upregulated soon after the shift, suggesting they were involved in a response to oxidative stress. The flagellar-biosynthesis genes were expressed in a hierarchical manner at 15 to 60 min after the shift. Numerous transporters were induced at various time points, suggesting that the cellular composition went through significant changes during the transition from anaerobic photosynthesis to aerobic respiration. Analyses of these data make it clear that numerous regulatory activities come into play during the transition from one homeostatic state to another.
Two Segments in Bacterial Antizyme P22 Are Essential for Binding and Enhance Degradation of Lysine/Ornithine Decarboxylase in
Selenomonas ruminantium
Authors: Yamaguchi Yoshihiro , Takatsuka Yumiko , Kamio Yoshiyuki
Published: October 2007

In
Selenomonas ruminantium
, a strictly anaerobic and gram-negative bacterium, the degradation of lysine/ornithine decarboxylase (LDC/ODC) by ATP-requiring protease(s) is accelerated by the binding of P22, which is a ribosomal protein of this strain. Amino acid sequence alignment of
S. ruminantium
P22 with the L10 ribosomal proteins of gram-positive and -negative bacteria showed that P22 has a 5-residue K
101
NKLD
105
segment and an 11-residue G
160
VIRNAVYVLD
170
segment, both of which are lacking in L10 in any other gram-positive and gram-negative bacteria reported. To elucidate whether the two segments are involved in P22 function, a series of mutant genes of P22 were constructed and expressed in
Escherichia coli
. The proteins were isolated and assayed for their function with respect to
S. ruminantium
LDC/ODC and mouse ODC. The results indicated that the two segments of P22 are crucial for P22 binding to both enzymes and also accelerated degradation of both decarboxylases.
Two Closely Related ABC Transporters in
Streptococcus mutans
Are Involved in Disaccharide and/or Oligosaccharide Uptake
Authors: Webb Alexander J. , Homer Karen A. , Hosie Arthur H. F.
Published: October 2007

Streptococcus mutans
has a large number of transporters apparently involved in the uptake of carbohydrates. At least two of these, the multiple sugar metabolism transporter, MsmEFGK, and the previously uncharacterized MalXFGK, are members of the ATP-binding cassette (ABC) superfamily. Mutation analysis revealed that the MsmEFGK and MalXFGK transporters are principally involved in the uptake of distinct disaccharides and/or oligosaccharides. Furthermore, the data also indicated an unusual protein interaction between the components of these two related transporters. Strains lacking
msmE
(which encodes a solute binding protein) can no longer utilize raffinose or stachyose but grow normally on maltodextrins in the absence of MalT, a previously characterized EII
mal
phosphotransferase system component. In contrast, a mutant of
malX
(which encodes a solute binding protein) cannot utilize maltodextrins but grows normally on raffinose or stachyose. Radioactive uptake assays confirmed that MalX, but not MsmE, is required for uptake of [U-
14
C]maltotriose and that MalXFGK is principally involved in the uptake of maltodextrins with as many as 7 glucose units. Surprisingly, inactivation of the corresponding ATPase components did not result in an equivalent abolition of growth: the
malK
mutant can grow on maltotetraose as a sole carbon source, and the
msmK
mutant can utilize raffinose. We propose that the ATPase domains of these ABC transporters can interact with either their own or the alternative transporter complex. Such unexpected interaction of ATPase subunits with distinct membrane components to form complete multiple ABC transporters may be widespread in bacteria.
p300 expression repression by hypermethylation associated with tumour invasion and metastasis in oesophageal squamous cell carcinoma
Authors: Zhang Changsong , Li Ke , Wei Lixin , Li Zhengyou , Yu Ping , Teng Lijuan , Wu Kusheng , Zhu Jin
Published: October 2007

Background:

Aberrant promoter methylation is an important mechanism for gene silencing.

Aims:

To evaluate the promoter methylation status of p300 gene in patients with oesophageal squamous cell carcinoma (OSCC).

Methods:

The methylation status of p300 promoter was analysed by methylation-specific PCR (MSP) in 50 OSCC tissues and the matching non-cancerous tissues. Oesophageal cancer cell lines (ECa-109 and TE-10) were treated with the demethylation agent 5-aza-2′-deoxycytidine (5-Aza-CdR), and p300 mRNA expression was detected by RT-PCR.

Results:

p300 methylation was found in 42% (21/50) of the OSCC tissues, but in only 20% (10/50) of the corresponding non-cancerous tissues (p = 0.017). In OSCC samples, 65% of those with deep tumour invasion (adventitia) and 63% samples with metastasis revealed p300 promoter methylation (p<0.05). p300 mRNA expression was observed in 19.0% (4/21) of methylated tumours and 58.6% (17/29) of unmethylated tumours (p = 0.005). In addition, p300 mRNA expression was observed in 40% (4/10) of methylated non-neoplastic tissues and 87.5% (35/40) of unmethylated non-tumours (p = 0.001). The demethylation caused by 5-Aza-CdR increased the p300 mRNA expression levels in oesophageal cancer cell lines.

Conclusions:

p300 transcription silenced by promoter hypermethylation could play a role in the pathogenesis of oesophageal squamous cell carcinoma.
Properties of polar mesospheric clouds measured by Odin/OSIRIS in the northern hemisphere in 2002–2005
Authors: Petelina S V , Llewellyn E J , Degenstein D A
Published: October 2007

Interseasonal variations in the properties of Polar Mesospheric Clouds (PMC) measured by the Optical Spectrograph and InfraRed Imager System (OSIRIS) on the Odin satellite during the northern hemisphere (NH) summers of 2002–2005 are described in this work. The lowest PMC latitudes were about 50°N for every season with the number of detections smallest in 2002 and largest in 2004. In 2004 and 2005, the detection of PMCs at lower latitudes was asymmetric with the larger number of clouds observed during the first half and fewer at during the second half of the season. PMC occurrence frequency in 2002 was 25–30% lower than in 2003–2005, and the season duration was shortest in 2002 and longest in 2004. For all NH seasons except 2002, PMC occurrence frequency was systematically 20–50% higher than the Solar Mesosphere Explorer climatology. Similar to PMC occurrence frequency, cloud brightness was lowest in 2002 and highest in 2004 at all latitudes. The daily mean brightness maximum at 50°–60°N was less than 8% of that at highest latitudes. This contrasts with the maximum PMC occurrence frequency that reached nearly 30% at these latitudes in 2004 and 2005. PMC brightness showed no apparent seasonal asymmetry at lower latitudes in 2004 and 2005 that was seen in the occurrence frequency. Significant, by about a factor of 2, oscillations observed in the daily mean cloud brightness at high latitudes were also not seen in the corresponding occurrence frequency. These results suggest that the occurrence frequency alone does not provide detailed information on the cloud population and ice mass in the mesosphere. There is no significant interannual variability in the seasonal mean OSIRIS PMC altitude. Its value was very close to 8350 km for all seasons except 2004 when it was 83.42 km. The mean PMC altitudes for each season increased by 0.3–0.6 when the minimum altitude in the database was increased from 80 to 82 km.

PACS Nos.: 92.05.Fg, 92.60.hc, 92.60.Jq, 92.60.Mt, 92.60.Nv, 92.60.Vb
An evaluation of Odin/OSIRIS limb pointing and stratospheric ozone through comparisons with ozonesondes
Authors: McLinden C A , Fioletov V E , Haley C S , Lloyd N , Roth C , Degenstein D , Bourassa A , McElroy C T , Llewellyn E J
Published: October 2007

Five-plus years of Odin/OSIRIS (Optical Spectrograph and Infrared Imager System) ozone profiles (version 3.0 and SaskMART) have been compared with coincident ozonesonde profiles from the tropopause to the middle stratosphere (~10–35 km). The OSIRIS(v3.0)-sonde comparisons, together with the “knee” technique, suggest that OSIRIS pointing is stable with an accuracy (systematic uncertainty) of 100~m and a precision (random uncertainty) of 400 m. Comparison of coincident profiles revealed excellent overall agreement with differences generally not exceeding 10% between 10 and 35 km. During periods of satellite eclipse larger differences above 25 km were found and concluded to be the result of flexing of the spacecraft frame brought about by cooling. Uncertainties derived from the intercomparison suggest an OSIRIS precision of 25–30% at 10 km, reaching a minimum of about 4–6% in the middle-stratosphere (23–28 km), and 6–8% at 35 km. Ozonesonde uncertainties were also derived and found to be slightly larger in the tropics than mid-latitudes, possibly due to a lack of column normalization at some of the tropical stations. OSIRIS SaskMART ozone, an alternative ozone data product, was found to be very comparable with the v3.0 ozone, with slightly smaller biases relative to the ozonesondes. OSIRIS is concluded to be a robust and accurate source of stratospheric ozone profiles.

PACS Nos.: 82.33.Tb, 95.75.Qr, 42.68.–w
Intercomparison of Odin/SMR ozone measurements with MIPAS and balloon sonde data
Authors: Jones A , Murtagh D , Urban J , Eriksson P , Rösevall J
Published: October 2007

The Sub-Millimetre Radiometer (SMR) on board Odin measures various important atmospheric species, including stratospheric ozone. In this study, we compare the three versions (v1.2, v2.0, and v2.1) of level 2 Odin/SMR global stratospheric ozone data to coincident level 2 MIPAS V4.61 and balloon sonde stratospheric ozone data during 2003. The most current product from Odin/SMR (at time of writing), the v2.1, showed the smallest systematic differences when compared to coincident MIPAS and sonde data. Between 17 and 55 km, v2.1 values agreed with MIPAS within 10% (a maximum of 0.42 ppmv), while comparisons to sonde measurements showed an agreement of typically 5–10% between 22 and 35 km (less than 0.5 ppmv below 33 km). Tropical latitudes below 35 km presented the largest absolute systematic differences between v2.1 and sonde coincidences, where Odin/SMR was systematically lower by ~0.9 (more than 10% difference) at approximately 30 km. Comparisons concerning the previous two Odin/SMR versions showed much larger systematic differences, especially at the higher and lower stratospheric altitudes. The main conclusion here is that we suggest that v2.1 of Odin/SMR ozone data should be used for scientific studies.

PACS Nos.: 92.60.hd, 95.75.Rs, 95.85.Fm
OSIRIS observations of a tongue of NOx in the lower stratosphere at the Antarctic vortex edge: comparison with a high-resolution simulation from the Global Environmental Multiscale (GEM) model
Authors: Sioris C E , Chabrillat S , McLinden C A , Haley C S , Rochon Y J , Ménard R , Charron M , McElroy C T
Published: October 2007

Selected NOx profiles of the Antarctic lower stratosphere inferred from OSIRIS NO2 observations are presented from the austral spring of 2003. These observations show a tongue of NOx at 100 hPa, with a concentration typical of the middle stratosphere. Simulations with the Global Environmental Multiscale model show that this small-scale tongue of NOx-rich air descended into the lower stratosphere. The tongue was formed as a result of a Rossby wave breaking days earlier, transporting NOx from the pole, where larger concentrations had recently appeared, to the edge of the vortex. The three-dimensional structure of the breaking wave is illustrated in detail.

PACS Nos.: 92.60.hf, 92.60.Xg, 93.30.Ca
Assessment of the quality of the ozone measurements from the Odin/SMR instrument using data assimilation
Authors: Massart S , Piacentini A , Cariolle D , Amraoui L El , Semane N
Published: October 2007

Space-based remote-sensing instruments providing atmospheric measurements have different time and space resolutions, and coverage. This makes the direct comparison of the measurements very difficult. Data assimilation has proven to be a far more powerful tool than simple interpolation techniques to create three-dimensional analyzed fields for a given data set. In this paper, we describe how the assimilation of ozone data from the Odin/SMR instrument can be used to assess its precisions and biases against other ozone-measuring instruments. To assess the quality of Odin/SMR ozone retrievals by MOLIERE-5 against ozonesondes, Envisat/MIPAS, Earth Probe/TOMS, and UARS/HALOE data, we use a three-dimensional variational assimilation scheme applied to the Météo-France MOCAGE chemistry transport model. The MOCAGE-PALM assimilation system has been already used by Météo-France and CERFACS to analyse the Envisat/MIPAS data for the ASSET intercomparison exercise. We have further developed and calibrated the configuration of this system to better account for the Odin/SMR ozone profiles. The upgraded system is used to assimilate the Odin/SMR ozone during the August 2003 – November 2003 period and intercomparisons are made with the other ozone measuring techniques. The Odin/SMR analysis and the other ozone data sets are in good agreement at mid and high latitudes, while in the lower tropical stratosphere, we found a positive bias of the Odin/SMR, Envisat/MIPAS, and Earth Probe/TOMS data compared to measurements from UARS/HALOE and ozonesondes. The precision of Odin/SMR ozone retrievals in terms of standard deviation is about 20% in the tropics, below 10% at high southern latitudes, and below 5% at high northern latitudes.

PACS No.: 82.33.Tb
The retrieval of vertical profiles of the ozone number density using Chappuis band absorption information and a multiplicative algebraic reconstruction technique
Authors: Roth C Z , Degenstein D A , Bourassa A E , Llewellyn E J
Published: October 2007

A new algorithm, SaskMART, is presented that uses observations of limb-scattered sunlight and a radiative transfer model to determine the ozone number-density profile up to 35 km altitude. In practice, clouds limit the lower extent of the retrieval to around 15 km but if the troposphere is clear the retrieval can be extended to altitudes as low as 10 km. SaskMART is an iterative Multiplicative Algebraic Reconstruction Technique that generates accurate results and is insensitive to the initial estimate of the ozone profile. Examples are presented using the OSIRIS limb-scattered radiance measurements and good agreement has been found when these results are compared with those derived from SAGE II measurements.

PACS Nos.: 33.20.Kf, 33.20.Lg, 42.68.Ca, 42.68.Mj, 92.60.H–, 92.60.hd
A comparison of NO2 absorption measurements from an FTIR spectrometer and the OSIRIS spectrograph
Authors: Puckrin E , Evans W FJ
Published: October 2007

Spectral measurements of the transmission of a gas cell filled with various amounts of NO2 were obtained with two instruments, a Fourier-transform infrared (FTIR) spectrometer and the OSIRIS spectrograph of the grating type. Five different gas-cell concentrations were investigated for the purpose of calibrating the OSIRIS instrument in the 400–700 nm region where NO2 absorbs visible radiation. The NO2 column amounts derived from the OSIRIS measurements ranged from 6.05 × 1017 to 1.17 × 1016 molecules/cm2, and agreed within 10% of the values determined from the FTIR measurements. These measurements suggest that the OSIRIS spectrograph is well suited for the remote sensing of atmospheric NO2.

PACS Nos.: 07.60.Rd, 07.87.+v, 32.30.Jc, 39.30.+w, 42.68.Ca, 82.33.Tb, 97.70.Cp
Comparison of OSIRIS stratospheric NO2 and O3 measurements with ground-based Fourier transform spectrometer measurements at the Toronto Atmospheric Observatory
Authors: Taylor J R , Strong K , McLinden C A , Degenstein D A , Haley C S
Published: October 2007

Stratospheric NO2 and O3 retrieved from measurements of limb-scattered sunlight made by the Optical Spectrograph and InfraRed Imager System (OSIRIS) are compared with like observations made by a ground-based infrared Fourier Transform Spectrometer at the Toronto Atmospheric Observatory (TAO-FTS). Two different versions of OSIRIS NO2 are compared (DOAS version 3.0 and MART version 2.0) with partial column concentrations retrieved from the TAO-FTS. Two OSIRIS O3 versions are also compared (Triplet version 3.0 and MART version 2.0) with O3 retrieved from the TAO-FTS. To accommodate the most coincidences, comparisons are based on monthly mean stratospheric partial columns covering 16–50 km. All coincident monthly means display high correlations: 0.82–0.97. The monthly mean NO2 at TAO compared with the monthly mean NO2 from OSIRIS shows an average difference of less than ~3% with standard deviations up to 6%. The OSIRIS NO2 observations show a multiplicative bias of ~0.8–0.9 and a systematic difference of 5–10% greater then those of the TAO-FTS. O3 differences are less than 5%, on average, with standard deviations ranging from 2% to 2.8%. There is a pronounced multiplicative bias of OSIRIS compared with the TAO-FTS ranging from 0.55 to 0.73. The systematic O3 differences are less than 5% larger for OSIRIS. These small differences meet the standards outlined in the Integrated Global Observing Strategy and confirm the quality of the OSIRIS data for studying stratospheric ozone and nitrogen chemistry.PACS{ 92.60.hd, 92.60.Ry, 92.70.Cp, 93.30.Hf
DDQ-promoted thiocyanation of aromatic and heteroaromatic compounds
Authors: Memarian Hamid R , Mohammadpoor-Baltork Iraj , Nikoofar Kobra
Published: October 2007

Thiocyanation of various aromatic and heteroaromatic compounds has been achieved using ammonium thiocyanate in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in methanol solution at room temperature and under reflux condition. The rate of reaction is influenced by the electron-donor ability of the aromatic nucleus.Key words: amines, DDQ, indoles, thiocyanation.
Cross-conjugated Z- and E-3-ferrocenylmethyl-idene-4-methyl-2-phenylpenta-1,4-dienes — Synthesis and some chemical properties
Authors: Mendoza Juan Manuel Martínez , Ramírez Lena Ruíz , Toscano Ruben Alfredo , Ortega Simon Hernández , Toledano Cecilio Alvarez , Alamo Marcos Flores , Klimova Elena I
Published: October 2007

Dehydration of (Z)- and (E)-4-ferrocenyl-3-isopropenyl-2-phenylbut-3-en-2-ols and Z-3-ferrocenyl methyl idene-4-methyl-2-phenylpentane-2,4-diol affords (Z)- and (E)-3-ferrocenylethylidene-4-methyl-2-phenylpenta-1,4-dienes with a system of three cross-conjugated double bonds. One of the methylidene groups of the trienes obtained is smoothly protonated under the action of tetrafluoroboric acid etherate to yield (Z)- and (E)-3-ferrocenyl-2-isopropenyl-1-methyl-1-phenylallyl tetrafluoroborates. The cross-conjugated trienes undergo cationic cycloaddition to these allylic cations as well as proton-induced cyclodimerization resulting in 7-ferrocenyl-4-ferrocenylmethylidene-1,3-dimethyl-5-phenyl-8-(1-phenylethylidene)bicyclo[3.3.1]non-2-ene and isomeric 1,5-diferrocenyl-2,6-diisopropenyl-3,7-diphenylocta-1,3,6-trienes.Key words: cross-conjugated trienes, ferrocenylallylic cations, cyclodimerization, cycloaddition, ferrocene.
Synthesis, crystal structure, and growth inhibition of human hepatoma cell (HepG2) of polyphenolic compounds based on gallates
Authors: Xiao Zhu-Ping , Fang Rui-Qin , Shi Lei , Ding Hui , Xu Chen , Zhu Hai-Liang
Published: October 2007

Seven compounds (1–7) based on gallate were synthesized and characterized by elemental analysis, 1H NMR, and MS spectra. 2-(3,5-Dibenzyloxy-4-methoxy)phenyl-2-propanol (6) was a new compound. Methyl 3,5-dihydroxy-4-methoxybenzoate (3), methyl 3,5-dibenzyloxy-4-methoxybenzoate (4), 3,5-dibenzyloxy-4-methoxybenzyl alcohol (5), and compound 6 were structurally determined by single-crystal X-ray diffraction for the first time. Crystallographic data for 3: space group P212121; a = 4.0750(8) Å, b = 7.5880(15) Å, c = 29.802(6) Å; V = 921.5(3) Å3; Z = 4. 4: space group P-1; a = 10.068(2) Å, b = 10.499(2) Å, c = 11.388(2) Å; α = 76.84(3)°, β = 66.79(3)°, γ = 64.10(3)°; V = 993.0(3) Å3, Z = 2. 5: space group P-1; a = 8.1410(16) Å, b = 8.7590(18) Å, c = 12.879(3) Å; α = 91.66(3)°, β = 94.69(3)°, γ = 91.73(3)°; V = 914.4(3) Å3; Z = 2. 6: space group P21/c; a = 5.8100(12) Å, b = 15.778(3) Å, c = 23.237(5) Å; β = 96.09(3)°; V = 2118.1(7) Å3; Z = 4. All of the seven compounds were evaluated for the inhibition of growth of human hepatoma (HepG2) cells. Comparison with the positive-control 5-fluorouracil (IC50 51.6 µmol/L), 5 showed stronger cytotoxic activity with an IC50 around 15.3 µmol/L, while IC50 value of 3 was 90.3 µmol/L. The effect of slight structural variations in this series of compounds was found to cause a marked change in their activity against HepG2 cells.Key words: gallates, benzyl alcohol, human hepatoma cells, crystal structure, anti-cancer activities.
An ab initio investigation of bismuth hydration
Authors: Pye C C , Gunasekara C M , Rudolph W W
Published: October 2007

A series of geometry, frequency, and energy calculations of aquabismuth(III) complexes were carried out at up to the MP2/CEP-121G* level. A thorough examination of all species up to and including enneacoordinate species was carried out. The structures of the complexes are compared with experimental data where available. Deviations from the most highly symmetric structures are consistent with the inert-pair effect. In addition, protonated bismuth–oxo clusters of the stoichiometry Bi6O8–n(OH)n(2+n)+, n = 0–4 are examined. The Raman spectrum of bismuth perchlorate with added perchloric and hydrochloric acid is measured.Key words: bismuth, aqua complexes, ab initio, Raman spectra.
On the origin of some cubebene derivatives — Diels–Alder adducts and the diene structures of solidago compounds
Authors: Jankowski Christopher K , Pelletier André , Diaz T. Eduardo , Belanger Jacqueline M.R , Paré Jocelyn J.R , Aumelas Andre , Besson Thierry , Pereira Maria de Fatima , Mauclaire Laurent
Published: October 2007

Two reactions, HCl addition and the thermal and (or) microwave assisted Diels–Alder condensation, were performed on α-cubebene (1), a vinylcyclopropane-containing tricyclic sesquiterpene. The diene structures originating from these reactions and from subsequent rearrangements of 1 were identified. The stereochemistry of the resulting adducts was established using mostly 2D high-resolution NMR.Key words: cubebene, tricyclic terpenes from Solidago Canadensis L, Diels-Alder microwave condensation on vinylcyclopropane system.
Glycoluril-derived crown clips as new ditopic receptors
Authors: Rahimizadeh Mohammad , Seresht E Rezaei , Bakavoli Mehdi , Pordel Mehdi
Published: October 2007

Several new ditopic receptors have been synthesized from 4,4′-bis(methoxyphenyl)glycoluril (1). The first receptor site is a cleft composed of two fused 2-imidazolone rings, which are flanked by two aromatic side walls, and the second site is a crown ether moiety.Key words: receptors, crown compounds, glycoluril, molecular clips.
Hwangryunhaedogtang (Huanglianjiedutang) Treatment for Pathological Laughter after Stroke and Importance of Patterns Identification: A Preliminary Study
Authors: Yun Sang Pil , Jung Woo Sang , Park Sung Uk , Moon Sang Kwan , Park Jung Mi , Ko Chang Nam , Cho Ki Ho , Kim Young Suk , Bae Hyung Sup
Published: October 2007

This study was to test the importance of patterns identification (PI) and the effectiveness of Hwangryunhaedogtang (Huanglianjiedutang) (HT) treatment for patients with post stroke pathological laughter (PL). Fourteen subjects were enrolled. Eight subjects diagnosed with Yang Excess patterns (YEP) were assigned into group A and 6 subjects who had no YEP to group B. HT was administrated 3 times a day for 14 days to both groups. The duration of PL at one time, the frequency of PL in a day, and pathological laughter scale (PLS) were the primary outcome measures. Barthel index (BI) was the secondary outcome measure. The duration and the frequency of PL in group A were significantly decreased from 10.88 ± 4.67 to 6.63 ± 4.07 sec and from 6.38 ± 2.72 to 3.00 ± 1.77 times, respectively (p = 0.01) after 14 days administration of HT. PLS in group A was also significantly lowered from 9.13 ± 1.73 to 4.75 ± 0.71 points (p = 0.01). However, significant differences were not observed in BI in group A and in the primary and secondary outcome measures in group B. The duration and the frequency of PL and PLS were more markedly reduced in group A than in group B (p = 0.01, 0.02, and < 0.01, respectively). These results suggested that HT could be effective on subjects with post stroke PL diagnosed as YEP and PI, that prescription of herbal medications to such patients should be considered.
Effect of in vitro Cultured Anoectochilus formosanus on Lipid Metabolism in Clinical Uses
Authors: Du Xiao-Ming , Sun Ning-Yi , Furusho Norihiro , Hayashi Jun , Shoyama Yukihiro
Published: October 2007

A clinical study was performed on the effect of in vitro cultured Anoectochilus formosanus HAYATA on lipid-metabolism. Sixty-six volunteers, including 36 healthy, 14 high-triglyceride-, 11 high-cholesterol- and 5 high-triglyceride- and high cholesterol- subjects, were administrated with A. formosanus (450 mg/day) for 6 months or 12 months. A. formosanus significantly decreased the concentrations of the serum levels of cholesterol, low density lipoprotein and very low density lipoprotein in all volunteers. The results of the present study suggested that A. formosanus might function as a liver activator resulting in improvement of lipid-metabolism.
Quantification of DeQi Sensation by Visual Analog Scales in Healthy Humans after Immunostimulating Acupuncture Treatment
Authors: Kou Wei , Gareus Isabel , Bell John D. , Goebel Marion U. , Spahn Günther , Pacheco-López Gustavo , Bäcker Marcus , Schedlowski Manfred , Dobos Gustav J.
Published: October 2007

Acupuncture is the most popular component of traditional Chinese medicine in Western countries. However, the mechanisms of its effects remain unclear. The therapeutic effect of acupuncture appears when a sensation of DeQi is achieved. We previously reported that repeated, but not single acupuncture treatment affected leukocyte circulation and blood pressure in healthy young humans. The objective of this study was to quantify DeQi sensation by using visual analog scales (VASs) and, to test whether DeQi induction is an important factor for the therapeutic effects of acupuncture in the same cohort. After either acupuncture or sham-acupuncture (placebo) treatment, a questionnaire containing five individual VASs was given to subjects to evaluate their DeQi sensation, including numbness, pressure, heaviness, warmth, and radiating paraesthesia, respectively. A separate VA S to measure their levels of anxiety during the treatment was also included. Our results showed that acupuncture significantly induced higher VA S values for numbness, pressure, warmth, and radiating paraesthesia, but not for heaviness than the placebo across three treatment sessions. Additionally, acupuncture did not induce higher anxiety levels than the placebo. These data confirm that VAS is an objective and reliable way to quantify DeQi sensation and, indicate that DeQi is unique to verum acupuncture treatment. Furthermore, either acupuncture-induced therapeutic effects or DeQi sensation should not be attributed to the stress-mediated effects. In summary, the induction of DeQi in each treatment session is an important factor for the physiological outcomes of repeated acupuncture treatment, and VASs offer objective, an easy and reliable way to assess it.
Co-administration of Dalbergia odorifera Increased Bioavailability of Salvia miltiorrhizae in Rabbits
Authors: Zheng Xiaohui , Zhao Xinfeng , Wang Shixiang , Luo Kai , Wei Yinmao , Zheng Jianbin
Published: October 2007

This study was to investigate the effect of Dalbergia odorifera (DO) on the pharmacokinetics of Danshensu in Salvia miltiorrhiza (SM) in healthy rabbits and rabbits with qi-stagnancy and blood stasis. Thirty two healthy rabbits were involved in the whole experiment. Qi-stagnancy and blood stasis rabbits were obtained by treating the limbs of 16 adnephrin rabbits in an ice-bath for 6.0 min. The rest of rabbits were equally divided into 2 healthy groups. One healthy group and 8 qi-stagnancy and blood stasis rabbits were orally administrated with SM (5.0 g/kg), and the other 8 healthy rabbits and 8 qi-stagnancy and blood stasis rabbits with SM (5.0 g/kg) coupled with DO (2.5 g/kg). The plasma (Danshensu) concentration–time curve was measured by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-trap mass (MS-MS). Danshensu in plasma was confirmed to be two-compartment open model with a first order absorption phase in all groups. Moreover, the area under curve (0-∞) of Danshensu was significantly increased both in healthy group and in qi-stagnancy and blood stasis group after administration of SM coupled with DO. This result was in accordance with the “Jun-Shi pairing herbs theory” of traditional Chinese medicine (TCM).
Hematopoietic Effect of Fractions from the Enzyme-Digested colla corii asini on Mice with 5-Fluorouracil Induced Anemia
Authors: Wu Hongzhong , Yang Fan , Cui Shuya , Qin Yufeng , Liu Jianwen , Zhang Yuanxing
Published: October 2007

Effects of fractions A and B from enzyme-digested traditional Chinese medicine colla corii asini on mice with 5-fluorouracil-induced anemia were investigated. The purpose of this study was to further understand the hematopoietic activities and mechanisms of colla corii asini. The fractions A and B were administered to anemic mice for 12 days. After confirming the anti-anemic effect of fractions A and B, we examined the effects of fractions A and B on immature granulocyte and erythroid cell activity and plasma cytokine level. Fraction A administration at 2 g/kg and 1 g/kg and fraction B administration at 1.6 g/kg and 0.8 g/kg activated granulocyte and erythrocyte progenitor cells in bone marrow and erythrocyte progenitors in spleen, led to the recovery of white blood cell and red blood cell counts, and increased the percentage of peripheral reticulocytes in red cells. The GM-CSF and EPO production determined by examining GM-CSF mRNA and EPO mRNA in the kidney and liver of the anemic mice were also enhanced. This treatment significantly increased serum GM-CSF and EPO level and lowered serum transforming growth factor ( TGF -β) level. These results suggested that fractions A and B promoted hematopoiesis by activating immature granulocyte and erythroid cells, partly by stimulating GM-CSF and EPO secretion and suppressing TGF -β release. Identification of a specific peptide or protein is still required for the development of a novel medicine for anemia caused by malignancy or chemotherapy.
Haeamtang Induces Apoptosis of Colon Cancer HT-29 Cells through Activation of Caspase-3
Authors: Moon Phil-Dong , Koo Hyun-Na , Jeong Hyun-Ja , Na Ho-Jeong , Kim Su-Jin , Hwang Gab-Soo , Han Na-Ra , Hong Seung-Heon , Kim Hyung-Min , Um Jae-Young
Published: October 2007

The effect of Haeamtang (HAT) on the colon cancer HT-29 cells was investigated in this study. A water extract of HAT significantly decreased the number of HT-29 cells in a dose-and time-dependent manner as determined by a MTT assay. Flow cytometry results revealed a dose- and time-dependent increase of dead cells in HT-29 cells treated with HAT extract. The anticancer activity of the H AT extract is attributed to apoptosis induced in HT-29 cells, which was demonstrated by increased caspase-3 activity and poly-ADP-ribose polymerase fragmentation. A selective caspase inhibitor, z-VAD-fmk, inhibited the HAT-induced cell death. Taken together, these results demonstrate that HAT extract induces apoptosis in HT-29 cells.
EFFECT OF ARGON–PLASMA TREATMENT ON THE ELECTRICAL AND OPTICAL PROPERTIES OF SOL–GEL ANTIMONY-DOPED TIN DIOXIDE THIN FILMS FABRICATED BY DIP COATING
Authors: HAMMAD T. M. , TAMOUS H. M. , HEJAZY N. K.
Published: October 2007

In this study, antimony-doped tin oxide (ATO) thin films were fabricated by the sol–gel dip coating process on glass substrates. After the deposition process, the films were treated by Argon–plasma (Ar-400 Watt). The effect of argon–plasma treatments on the electrical and optical properties of ATO thin films was then investigated as a function of the plasma treatment time. It was found that Ar–plasma treatment increased the electrical conductivity of ATO films, but it decreased the optical transmission of ATO thin films.
SHIL'NIKOV HETEROCLINIC ORBITS IN A CHAOTIC SYSTEM
Authors: SUN FENG-YUN
Published: October 2007

In this paper, a chaotic system which exhibits a chaotic attractor with only three equilibria for some parameters is considered. The existence of heteroclinic orbits of the Shil'nikov type in a chaotic system has been proved using the undetermined coefficient method. As a result, the Shil'nikov criterion guarantees that the system has Smale horseshoes. Moreover, the geometric structures of the attractor are determined by these heteroclinic orbits.
N-PARTICLE GENERAL W STATE AND PROBABILISTIC TELEPORTATION
Authors: HUANG YONG-CHANG , LIU M. , SUO MENG
Published: October 2007

We show a general W state of N-particle entanglement. Using four pairs of two-particle non-maximally entanglement states, we give a general scheme of probabilistic teleportation of the four-particle general W state by constructing a 5 × 5 projection transformation matrix different from the other references. The general scheme overcomes the difficulty of having to introduce an auxiliary state |0>A in order to get a complex unitary transformation matrix. Thus, we need not perform more operations and measurements than the past researches. We then give a general scheme of the probabilistic teleportation of the N-particle general W state by means of N pairs of general entanglement particles, and the scheme may be applied to all the researches and calculation about the probabilistic teleportation of N-particle entanglement general state by means of N pairs of general entanglement particles, and may simplify their researches, calculation, physical operations and measurements.
DISPERSION OF THE QUASI-CONFINED OPTICAL PHONONS IN WURTZITE GaN/AlN MULTIPLE QUANTUM WELLS
Authors: HUANG WEN DENG , WEI SHU YI , REN YA JIE , WANG YA HUI
Published: October 2007

Within the framework of the dielectric-continuum model and Loudon's uniaxial crystal model, the dispersions of the quasi-confined optical phonons in arbitrary wurtzite multiplelayer heterostructures are solved by using the transfer-matrix method. The dispersion relations of the quasi-confined phonons are investigated for GaN/AlN single QW and coupled QWs. The confinement of the quasi-confined phonons leads to a quantization of qz, j characterized by an integer m that defines the order of corresponding quasi-confined modes. The quasi-confined modes are more dispersive for decreasing m (i.e., for decreasing qz, j, the bands formed by the dispersion curves are narrower for higher order quasi-confined modes. The strain effect of QW structures has a clear influence on the dispersion behavior of the quasi-confined phonon modes and improves the frequency of the quasi-confined phonons.
THE ELECTRONIC BAND STRUCTURE OF GaN, GaAs AND InxGa1-xAs1-yNy ALLOYS
Authors: MOHAMMAD REZEK , KATIRCIOĞLU ŞENAY
Published: October 2007

The electronic band structure of GaN and GaAs has been investigated by ETB to obtain the band gap bowing of In x Ga 1-x As 1-y N y alloys lattice matched to GaAs . The ETB method has been formulated for sp3d2 basis and nearest neighbor interactions of the compounds, and its energy parameters have been derived from the results of the present first principles calculations carried out on GaN and GaAs . It has been found that the present ETB energy parameters are capable of producing the electronic band structure of corresponding compounds and the large bowing parameter of InGaAsN alloy.
A HYBRID MOVIE RECOMMENDER SYSTEM BASED ON NEURAL NETWORKS
Authors: CHRISTAKOU CHRISTINA , VRETTOS SPYROS , STAFYLOPATIS ANDREAS
Published: October 2007

Recommender systems offer a solution to the problem of successful information search in the knowledge reservoirs of the Internet by providing individualized recommendations. Content-based and Collaborative Filtering are usually applied to predict recommendations. A combination of the results of the above techniques is used in this work to construct a system that provides precise recommendations concerning movies. The content filtering part of the system is based on trained neural networks representing individual user preferences. Filtering results are combined using Boolean and fuzzy aggregation operators. The proposed hybrid system was tested on the MovieLens data yielding high accuracy predictions.
IMPROVING OBJECT DETECTION PERFORMANCE WITH GENETIC PROGRAMMING
Authors: ZHANG MENGJIE
Published: October 2007

This paper describes three developments to improve object detection performance using genetic programming. The first investigates three feature sets, the second investigates a new fitness function, and the third introduces a two phase learning method using genetic programming. This approach is examined on three object detection problems of increasing difficulty and compared with a neural network approach. The two phase GP approach with the new fitness function and the local concentric circular region features achieved the best results. The results suggest that the concentric circular pixel statistics are more effective than the square features for these object detection problems. The fitness function with program size is more effective and more efficient than without for these object detection problems and the evolved genetic programs using this fitness function are much shorter and easier to interpret. The two phase GP approach is more effective and more efficient than the single stage GP approach, and also more effective than the neural network approach on these problems using the same set of features.
MEMORY-BASED CLASSIFICATION WITH DYNAMIC FEATURE SELECTION USING SELF-ORGANIZING MAPS FOR PATTERN EVALUATION
Authors: PATERITSAS CHRISTOS , STAFYLOPATIS ANDREAS
Published: October 2007

Memory-based learning is one of the main fields in the area of machine learning. We propose a new methodology for addressing the classification task that relies on the main idea of the k-nearest neighbors algorithm, which is the most important representative of this field. In the proposed approach, given an unclassified pattern, a set of neighboring patterns is found, not necessarily using all input feature dimensions. Also, following the concept of the naïve Bayesian classifier, we adopt the assumption of independence of input features in the outcome of the classification task. The two concepts are merged in an attempt to take advantage of their good performance features. In order to further improve the performance of our approach, we propose a novel weighting scheme of the memory-base. Using the self-organizing maps model during the execution of the algorithm, dynamic weights of the memory-base patterns are produced. Experimental results have shown improved performance of the proposed method in comparison with the aforementioned algorithms and their variations.