bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Phenolic Glycosides from Clematis mandshurica
Authors: Shi She‐Po , Jiang Dan , Dong Cai‐Xia , Tu Peng‐Fei 
Published: May 2006

AbstractThree new phenolic glycosides, clemomandshuricosides A–C (1–3, resp.) and two new D‐ribono‐γ‐lactone derivatives, 4 and 5, were isolated from the roots and rhizomes of Clematis mandshurica Rupr., together with six known compounds. Their structures were elucidated on the basis of chemical, physicochemical, and spectroscopic evidence.
Application of a Grubbs–Hoveyda Metathesis Catalyst Noncovalently Immobilized by Fluorous–Fluorous Interactions
Authors: Michalek Florian , Bannwarth Willi 
Published: May 2006

AbstractA Grubbs–Hoveyda metathesis catalyst bearing a tris(perfluoroalkyl)silyl tag for efficient noncovalent attachment to fluorous silica gel (FSG) was synthesized and employed in ring‐closing metathesis (RCM) reactions in CH2Cl2. After the reaction, a solvent switch to a polar system allowed for recovery of the catalyst by filtration and its reuse. The approach was demonstrated for a number of different substrates. Furthermore, it was shown that the application of this catalytic system yielded products with low ruthenium content.
Reactions of Chlorosulfanyl Derivatives of Cyclobutanones with Different Nucleophiles
Authors: Majchrzak Agnieszka , Mlostoń Grzegorz , Linden Anthony , Heimgartner Heinz 
Published: May 2006

AbstractThe reactions of 3‐chloro‐3‐(chlorosulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one (2) with N, O, S, and P nucleophiles occur by substitution of Cl at the S‐atom. Whereas, in the cases of secondary amines, alkanols, phenols, thiols, thiophenols, and di‐ and trialkyl phosphates, the initially formed substitution products were obtained, the corresponding products with allyl and propargyl alcohols undergo a [2,3]‐sigmatropic rearrangement to give allyl and allenyl sulfoxides, respectively. Analogous substitution reactions were observed when 3‐chloro‐3‐(chlorodisulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one (3) was treated with N, O, and S nucleophiles. The reaction of 3 with Et3P led to an unexpected product via cleavage of the SS bond (cf. Scheme 13). In the reactions of 2 with primary amines and H2O, the substitution products react further via elimination of HCl to yield the corresponding thiocarbonyl S‐imides and the thiocarbonyl S‐oxide, respectively. Whereas the latter could be isolated, the former were not stable but could be intercepted by MeOH (Scheme 4) or adamantanethione (Scheme 5). The structures of some of the substitution products were established by X‐ray crystallography.
Cassane‐Type Diterpenes from the Seeds of Caesalpinia crista
Authors: Cheenpracha Sarot , Karalai Chatchanok , Ponglimanont Chanita , Chantrapromma Kan , Laphookhieo Surat 
Published: May 2006

AbstractA new dimer 1 and two new cassane‐type diterpenes 2 and 3, designated taepeenin J–L, were isolated from the seeds of Caesalpinia crista L. Compound 1 possesses a dimeric vouacapane skeleton. Their structures were elucidated on the basis of spectroscopic analysis.
Photocycloaddition of Cyclohex‐2‐enones to Penta‐1,2,4‐triene
Authors: Lohmeyer Britta , Schmidt Kerstin , Margaretha Paul 
Published: May 2006

AbstractDihydrothiinone 9a undergoes photocycloaddition regioselectively to all three CC bonds of penta‐1,2,4‐triene (10), the relative stabilities of the biradical intermediates determining the product distribution. In contrast, cyclohexenone 9b and dihydropyranone 9c afford more complex mixtures of bicyclo[4.2.0]octanones, which also turn out to be less stable on chromatographic workup, reflecting the higher strain due to the shorter bond lengths (CO and CC vs. CS) in the six‐membered rings, respectively.
Synthetic Applications of the Baylis–Hillman Reaction: Simple and Convenient Synthesis of Five Important Insect Pheromones
Authors: Das Biswanath , Banerjee Joydeep , Chowdhury Nikhil , Majhi Anjoy , Mahender Gurram 
Published: May 2006

AbstractA simple and convenient synthesis of five important insect pheromones by means of Baylis–Hillman adducts is described, i.e., of (2E,4S)‐2,4‐dimethylhex‐2‐enoic acid (1), a mandibular‐gland secretion of the male carpenter ant in the genus Camponotus, of (+)‐(S)‐manicone (2) and (+)‐(S)‐normanicone (3), two mandibular‐gland constituents of Manica ants, and of (+)‐dominicalure‐I (6) and (+)‐dominicalure‐II (7), two aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F). For the first time, the potential of the Baylis–Hillman chemistry for the stereoselective synthesis of trisubstituted olefins was successfully applied to the synthesis of these pheromone compounds.
Kadsutherins A–C: Three New Dibenzocyclooctane Lignans from the Stems of Kadsura Species
Authors: Lu Yan , Chen Daofeng 
Published: May 2006

AbstractThree new dibenzocyclooctane‐type lignans, kadsutherins A–C (1–3), were isolated from the stems of two Kadsura species. Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR and HR‐MS techniques. Kadsutherin C (3) is the first dibenzocyclooctane lignan without an oxygen‐containing substituent at C(2).
Arylethyl (= Phenylethanoid) Glycosides and Oligosaccharide from the Stem of Cistanche tubulosa
Authors: Tu Peng‐Fei , Song Zhi‐Hong , Shi Hai‐Ming , Jiang Yong , Zhao Yu‐Ying 
Published: May 2006

AbstractThree new analogues of the arylethyl (= phenylethanoid) glycoside echinacoside (5), namely cistantubulosides A (1), B1/B2 (2a/2b), and C1/C2 (3a/3b), and one new oligosaccharide, cistantubulose A1/A2 (4a/4b), were isolated from the stems of Cistanche tubulosa (Schenk) R. Wight, together with five known compounds, i.e., campneoside I, campneoside II (6), echinacoside (5), tubuloside, and cistanoside F. Among the compounds isolated, 2a/2b, 3a/3b, 4a/4b, campneoside I, campneoside II (6), and cistanoside F each consisted of a pair of epimers. The structures of the new compounds were elucidated on the basis of spectral data.
A Pair of New Nortriterpene Saponin Epimers from the Roots of Gypsophila oldhamiana
Authors: Luo Jian‐Guang , Kong Ling‐Yi 
Published: May 2006

AbstractA pair of new oleanane‐type nortriterpene saponin epimers, neogypsoside A (1) and B (2) (Fig. 1) with neogypsogenin A (3) and neogypsogenin B (4) as the two new aglycons, as well as the two known triterpene saponins 5 and 6 (Fig. 1), were isolated from the roots of Gypsophila oldhamiana. Their structures were determined by analysis of their NMR data. A possible biogenetic pathway to the nortriterpene saponins 1 and 2 is proposed (Scheme 2).
Triterpenoids from the Aerial Parts of Kalidium foliatum
Authors: Siddiqui Bina Shaheen , Karzhaubekova Zhanat Zhymabekovna , Burasheva Gauhar Shahmanovna , Sultanova Nurgyl Adaibaevna 
Published: May 2006

AbstractStudies on the chemical constituents of the aerial parts of Kalidium foliatum led to the isolation of three new olean‐12‐ene‐23,28‐dioic acids in their either partly or fully esterified forms (Me or glucosyl (Glc) esters), which were named kalidiumoside A (1), kalidiumin (2), and kalidiumoside B (3). Their structures were elucidated through spectral studies including 2D‐NMR experiments (HMQC, HMBC, COSY, NOESY) and J‐resolved spectra. Also isolated were the two known compounds dianic acid and dianoside F, which were identified through comparison of their spectroscopic data with those reported in the literature.
Secoprezizaane Sesquiterpene Lactones from Illicium micranthum
Authors: Dong Xu‐Jun , Zhu Xiang‐Dong , Wang Yi‐Feng , Wang Qiong , Ju Peng , Luo Shide 
Published: May 2006

AbstractThree new secoprezizaane sesquiterpene lactones, (1R,2S)‐1,2‐epoxyneomajucin (1), (2R)‐2‐hydroxyneomajucin (2), and (2R)‐2‐hydroxymajucin (3), along with six known compounds (4–9), were isolated from the poisonous shrub Illicium micranthum. Their structures were established by in‐depth analyses of spectroscopic and mass‐spectrometric data.
Effects of surface characteristics on infiltration patterns in an arid shrub desert
Authors: Wang Xin‐Ping , Li Xin‐Rong , Xiao Hong‐Lang , Berndtsson Ronny , Pan Yan‐Xia 
Published: May 2006

AbstractPrecipitation is often the sole source of water replenishment in arid and semi‐arid areas and, thus, plays a pertinent role in sustaining desert ecosystems. Revegetation over 40 years using mainly Artemisia ordosica and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou, China, has established a dwarf‐shrub and microbiotic soil crust cover on the stabilized sand dunes. The redistribution of infiltrated moisture through percolation, root extraction, and evapotranspiration pathways was investigated. Three sets of time‐domain reflectometry (TDR) probes were inserted horizontally at 5, 10, 15, 20, 30 and 40 cm depths below the ground surface in a soil pit. The three sets of TDR probes were installed in dwarf‐shrub sites of A. ordosica and C. korshinskii community with and without a microbiotic soil crust cover, and an additional set was placed in a bare sand dune area that had neither vegetation nor a microbiotic soil crust present. Volumetric soil moisture content was recorded at hourly intervals and used in the assessment of infiltration for the different surface covers. Infiltration varied greatly, from 7·5 cm to more than 45 cm, depending upon rainfall quantity and soil surface conditions. In the shrub community area without microbiotic soil crust cover, infiltration increased due to preferential flow associated with root tunnels. The microbiotic soil crust cover had a significant negative influence on the infiltration for small rainfall events (∼10 mm), restricting the infiltration depth to less than 20 cm and increasing soil moisture content just beneath the soil profile of 10 cm, whereas it was not as strong or clear for larger rainfall events (∼60 mm). For small rainfall events, the wetting front depth for the three kinds of surface cover was as follows: shrub community without microbiotic soil crust > bare area > shrub community with microbiotic soil crust. In contrast, for large rainfall events, infiltration was similar in shrub communities with and without microbiotic soil crust cover, but significantly higher than measured in the bare area. Soil water extraction by roots associated with evapotranspiration restricted the wetting front penetration after 1 to 3 h of rainfall. Copyright © 2006 John Wiley & Sons, Ltd.
A review of factors influencing the availability of dissolved oxygen to incubating salmonid embryos
Authors: Greig S. M. , Sear D. A. , Carling P. A. 
Published: May 2006

AbstractPrevious investigations into factors influencing incubation success of salmonid progeny have largely been limited to the development of empirical relationships between characteristics of the incubation environment and survival to emergence. It is suggested that adopting a process‐based approach to assessing incubation success aids identification of the precise causes of embryonic mortalities, and provides a robust framework for developing and implementing managerial responses.Identifying oxygen availability within the incubation environment as a limiting factor, a comprehensive review of trends in embryonic respiration, and processes influencing the flux of oxygenated water through gravel riverbeds is provided. The availability of oxygen to incubating salmonid embryos is dependent on the exchange of oxygenated water with the riverbed, and the ability of the riverbed gravel medium to transport this water at a rate and concentration appropriate to support embryonic respiratory requirements. Embryonic respiratory trends indicate that oxygen consumption varies with stage of development, ambient water temperature and oxygen availability. The flux of oxygenated water through the incubation environment is controlled by a complex interaction of intragravel and extragravel processes and factors. The processes driving the exchange of channel water with gravel riverbeds include bed topography, bed permeability, and surface roughness effects. The flux of oxygenated water through riverbed gravels is controlled by gravel permeability, coupling of surface–subsurface flow and oxygen demands imposed by materials infiltrating riverbed gravels. Temporally and spatially variable inputs of groundwater can also influence the oxygen concentration of interstitial water. Copyright © 2006 John Wiley & Sons, Ltd.
Modular changes of cis‐regulatory elements from two functional Pit1 genes in the duplicated genome of Cyprinus carpio
Authors: Kausel G. , Salazar M. , Castro L. , Vera T. , Romero A. , Muller M. , Figueroa J. 
Published: May 2006

AbstractThe pituitary‐specific transcription factor Pit1 is involved in its own regulation and in a network of transcriptional regulation of hypothalamo‐hypophyseal factors including prolactin (PRL) and growth hormone (GH). In the ectotherm teleost Cyprinus carpio, Pit1 plays an important role in regulation of the adaptive response to seasonal environmental changes. Two Pit1 genes exist in carp, a tetraploid vertebrate and transcripts of both genes were detected by RT‐PCR analysis. Powerful comparative analyses of the 5′‐flanking regions revealed copy specific changes comprising modular functional units in the naturally evolved promoters. These include the precise replacement of four nucleotides around the transcription start site embedded in completely conserved regions extending upstream of the TATA‐box, an additional transcription factor binding site in the 5′‐UTR of gene‐I and, instead, duplication of a 9 bp element in gene‐II. Binding of nuclear factors was assessed by electro mobility shift assays using extracts from rat pituitary cells and carp pituitary. Binding was confirmed at one conserved Pit1, one conserved CREB and one consensus MTF1. Interestingly, two functional Pit1 sites and one putative MTF1 binding site are unique to the Pit1 gene‐I. In situ hybridization experiments revealed that the expression of gene‐I in winter carp was significantly stronger than that of gene‐II. Our data suggest that the specific control elements identified in the proximal regulatory region are physiologically relevant for the function of the duplicated Pit1 genes in carp and highlight modular changes in the architecture of two Pit1 genes that evolved for at least 12 MYA in the same organism. J. Cell. Biochem. 99: 905–921, 2006. © 2006 Wiley‐Liss, Inc.
Modified gas‐perturbed liquid model (GPLM) for minimum fluidization velocity in a two‐phase inverse fluidized bed reactor with Newtonian and non‐Newtonian systems
Authors: Sivasubramanian V , Velan M 
Published: May 2006

AbstractIn the present investigation minimum fluidization velocity, Umf, in a two‐phase inverse fluidized bed reactor is determined using low‐density polyethylene and polypropylene particles of different diameters (4,6 and 8 mm) by measuring pressure drop. In a glycerol system Umf decreased gradually with increase in viscosity up to a value of 6.11 mPa s (60%) and on further increase there was a slight increase in Umf. In the case of the glycerol system the Umf was found to be higher when compared to water. In the non‐Newtonian system (carboxymethylcellulose), Umf decreased with increase in concentration in the range of the present study. The Umf was found to be lower when compared to water as liquid phase. The modified gas‐perturbed liquid model was used to predict the minimum fluidization liquid velocity (Ulmf) for Newtonian and non‐Newtonian systems. Copyright © 2006 Society of Chemical Industry
Isolation, identification and seasonal distribution of soilborne fungi in tea growing areas of Iyidere‐Ikizdere vicinity (Rize‐Turkey)
Authors: Karaoglu Sengul Alpay , Ulker Serdar 
Published: May 2006

AbstractThis study involves the isolation and identification of soil borne fungi from different altitudes of Iyidere‐Ikizdere vicinity in Rize, Turkey. The qualitative and quantitative fungal composition of the soil of Iyidere‐Ikizdere vicinity was surveyed seasonally during a year (between summer 2003 and spring 2004). The soil samples were collected from 10 different locations. Some physical and chemical properties of the soil samples were studied. Soil samples were observed to have the proper pH levels (pH 4.00–6.75) for the growth of microfungi. By using a soil dilution technique, the mycological analysis of 40 soil samples were studied at 25 cm depth. The number of microfungi ranged from 2,000–160,000 CFU g–1. 249 different microfungi belonging to 15 genera were isolated. 45 of the isolates were Mycelia Sterilia. Penicillium , Aspergillus , Trichoderma and Fusarium were the most abundant genera (26.8%, 14.8%, 9.6% and 8.4%, respectively). Penicillium phialosporum, Penicillium trzebinskianum and Gliocladium virens were reported for the first time in Turkey. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Practical thin layer chromatography techniques for diaminopimelic acid and whole cell sugar analyses in the classification of environmental actinomycetes
Authors: Schön Renate , Groth Ingrid 
Published: May 2006

AbstractFor the determination of diaminopimelic acid (DAP) stereoisomers in whole cell hydrolysates as chemotaxonomic markers of actinomycetes, two new pyridine‐free solvent systems for TLC on cellulose sheets have been introduced: methanol/0.05 m potassium hydrogenphthalate buffer pH 4 2:1 (v/v) and methanol/0.12 m dimethylaminopyridine (DMAP) in H2O pH 6 2:1 (v/v). The commercial (Sigma) DAP standard can be separated by repeated TLC into its three stereoisomers. Addition of a single stereoisomer to the samples supported the detection (presence or absence) of the relevant stereoisomer by HPLC. In the study on whole cell sugars, TLC both on cellulose and on silica gel revealed to be successful in the separation of the components in modified pyridine‐free solvent systems. The procedures of DAP and sugar analyses are summarized in two flow‐charts. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Separating climatic and possible human impacts in the early Holocene: biotic response around the time of the 8200 cal. yr BP event
Authors: Edwards Kevin J. , Langdon Peter G. , Sugden Heather 
Published: May 2006

AbstractThe early Holocene is characterised by rapid climate change events, which in the North Atlantic region are often associated with changes in thermohaline circulation. Superimposed on this in northwest Europe is localised evidence for human impact on the landscape, although separating climatic and anthropogenic mechanisms for environmental change is often difficult. Biotic and sedimentological evidence from a lacustrine sequence from the Inner Hebrides, Scotland, shows a considerable reduction in inferred local woodland centred upon 8250 cal. yr BP. These data correlate precisely with a distinctive rise in the charcoal:pollen ratio and hence suggest a possible Mesolithic human impact upon the vegetation around this time. A quantitative temperature reconstruction from chironomid analyses from the same sequence, supported by sedimentological data, indicates that the fall in arboreal pollen taxa occurred as climate warmed significantly during the early Holocene. This warming was followed by a significant cold event, with mean July temperatures reduced by 2°C, that lasted for at least 320 years ca. 7790–7470 cal. yr BP. Woodland recovered during this phase suggesting that the vegetation during the 8250 cal. yr BP interval was likely to have been responding to human activity, and not climate, and hence it is possible at specific sites to separate the influence of these key drivers of environmental change. Copyright © 2006 John Wiley & Sons, Ltd.
Preneoplastic lesions in gallbladder cancer
Authors: Roa Iván , de Aretxabala Xabier , Araya Juan C. , Roa Juan 
Published: May 2006

AbstractBackgroundGallbladder cancer is an uncommon disease except in countries like Chile and areas of India and Japan. The knowledge regarding the etiology and mechanisms through which this neoplasia is developed is significantly less compared to other malignant tumors.ResultsThe epithelial lesions involved in gallbladder carcinogenesis are dysplasia and adenomas that represent two biologically distinct carcinogenetic models. Dysplasia progresses to carcinoma in situ (CIS) and subsequently becomes invasive. Over 80% of invasive gallbladder cancers present areas adjacent to the CIS and epithelial dysplasia. Other authors have demonstrated adenomatous areas in carcinomas, or malignant transformation in an adenoma. The low incidence of gallbladder adenomas (0.14% of cholecystectomies) and the presence of adenomatous remnants in the neighboring mucosa to early carcinomas in less than 3% of the cases suggest the limited importance of this carcinogenic pathway. Epithelial dysplasia which is not associated with gallbladder cancer is observed in approximately 1% of cholecystectomies for symptomatic lithiasis. Metaplasia, dysplasia, and CIS are present in the mucosa adjacent to the cancer in 66%, 81.3%, and 69%, respectively. The average ages of patients with dysplasia not associated to cancer (51.9 years), early carcinomas (56.8 years), and advanced carcinomas (62.9 years) demonstrate a gradient which suggests the progression of these lesions.ConclusionsFrom the morphological point of view, the dysplasia–carcinoma sequence is the most plausible carcinogenic pathway for gallbladder cancer, a process which would require a period of approximately 10 years. J. Surg. Oncol. 2006;93:615–623. © 2006 Wiley‐Liss, Inc.
Contribution of silent gallstones in gallbladder cancer
Authors: Tewari Mallika 
Published: May 2006

AbstractSilent (asymptomatic) gallstones are detected frequently with the widespread use of abdominal ultrasonography. The presence of gallstones is found strongly associated with gallbladder carcinoma. Studies on the natural history and most decision analysis studies do not favor prophylactic cholecystectomy for patients with silent gallstones. Gallbladder carcinoma is known to be highly aggressive and lethal disease with a poor outcome. It is rarely diagnosed early and only 10–30% patients are offered radical surgery on presentation. This has lead to a dilemma leading most surgeons to opt for an expectant management of silent gallstones. It thus raises the important question of the implications of leaving asymptomatic gallstones untouched. In this paper the author has reviewed the current understanding on silent gallstones and gallbladder carcinoma. J. Surg. Oncol. 2006;93:629–632. © 2006 Wiley‐Liss, Inc.
Infection as a risk factor for gallbladder cancer
Authors: Kumar Sandeep , Kumar Shailendra , Kumar Surender 
Published: May 2006

AbstractGallbladder cancer is a common hepato‐biliary malignancy with poor prognosis. The main associated risk factors identified so far include cholelithiasis (especially mixed gall stone), chronic infections of the gallbladder, obesity, reproductive factors, diet, hepato‐biliary anamolies, and environmental exposure to specific chemicals. Genetic and molecular predisposing factors have also been described. This article reviews the association of chronic infection and gallbladder cancer. Most of the studies have shown a good association of mixed bacterial and Salmonella infections in the carcinogenesis of cancer gallbladder especially in the area of high endemicity of typhoid. Bacterial degradation of bile and chronic inflammation may also play some role in the carcinogenic process. Mutations in multiple tumor suppressor gene and oncogenes (P53 and K‐ras) have also been found in a few studies. This review seeks to bring out many hidden infective etiological aspects of the pathogenesis of gallbladder cancer. Review of the entire published literature suggests a need for further studies for better understanding of the disease. J. Surg. Oncol. 2006;93:633–639. © 2006 Wiley‐Liss, Inc.