bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H2O2 as the Oxidant
Authors: Xu Senmiao , Wang Zheng , Li Yuxue , Zhang Xumu , Wang Haiming , Ding Kuiling 
Published: January 2010

AbstractThe mechanism of the chiral phosphoric acid catalyzed Baeyer–Villiger (B–V) reaction of cyclobutanones with hydrogen peroxide was investigated by using a combination of experimental and theoretical methods. Of the two pathways that have been proposed for the present reaction, the pathway involving a peroxyphosphate intermediate is not viable. The reaction progress kinetic analysis indicates that the reaction is partially inhibited by the γ‐lactone product. Initial rate measurements suggest that the reaction follows Michaelis–Menten‐type kinetics consistent with a bifunctional mechanism in which the catalyst is actively involved in both carbonyl addition and the subsequent rearrangement steps through hydrogen‐bonding interactions with the reactants or the intermediate. High‐level quantum chemical calculations strongly support a two‐step concerted mechanism in which the phosphoric acid activates the reactants or the intermediate in a synergistic manner through partial proton transfer. The catalyst simultaneously acts as a general acid, by increasing the electrophilicity of the carbonyl carbon, increases the nucleophilicity of hydrogen peroxide as a Lewis base in the addition step, and facilitates the dissociation of the OH group from the Criegee intermediate in the rearrangement step. The overall reaction is highly exothermic, and the rearrangement of the Criegee intermediate is the rate‐determining step. The observed reactivity of this catalytic B–V reaction also results, in part, from the ring strain in cyclobutanones. The sense of chiral induction is rationalized by the analysis of the relative energies of the competing diastereomeric transition states, in which the steric repulsion between the 3‐substituent of the cyclobutanone and the 3‐ and 3′‐substituents of the catalyst, as well as the entropy and solvent effects, are found to be critically important.
A New Synthesis of Charge‐Neutral Tris‐Pyrazolyl and ‐Methimazolyl Borate Ligands
Authors: Bailey Philip J. , Budd Laura , Cavaco Filipa A. , Parsons Simon , Rudolphi Felix , Sanchez‐Perucha Alejandro , White Fraser J. 
Published: January 2010

AbstractThe dimethylamine in the adducts [(HNMe2)B(azolyl)3] (azolyl=methimazolyl, pyrazolyl), obtained by reaction of the azole with B(NMe2)3, can readily be substituted with a range of nitrogen donors to provide new charge‐neutral, tripodal ligands in high yield. This observation has led to a revision of an earlier interpretation of the mechanism of the formation of these species. The donor properties of the ligands [(nmi)B(azolyl)3] (nmi=N‐methylimidazole) have been compared with their anionic analogues [HB(azolyl)3]− by synthesis of their manganese(I)–tricarbonyl complexes and comparison of their infrared νCO energies. This comparison indicates that the new neutral ligands are only marginally weaker donors than the corresponding anionic hydrotris(azolyl)borate ligands. This may be explained by the ability of the attached nmi ring to stabilize a positive charge remotely from the coordinated metal, which may also account for the fact that the [(nmi)B(pyrazolyl)3] ligand is a substantially stronger donor than the similarly neutral tris(pyrazolyl)methane ligand.
„KO2 can do“ – A Brief Glimpse into the Fascinating Properties of Potassium superoxide
Authors: Kunze Nicole , Oetken Marco 
Published: January 2010

AbstractDie Chemie der Alkali‐ und Erdalkalimetalle sowie deren Verbindungen ist vielfältig, technisch bedeutsam und somit folgerichtig Inhalt des Chemiecurriculums. Eine Substanz mit außergewöhnlichen chemischen Eigenschaften ist das Kaliumhyperoxid (früher Kaliumsuperoxid), das allerdings bisher in der Schulchemie keine besondere Rolle gespielt hat. Das Argument, es gäbe keine interessanten und motivierenden Experimente, möchte der Beitrag ein Stück weit entkräften.
“Forsche Schülerinnen forschen” – Promoting Girls' Interest in Science and Technology
Authors: Herriger Cornelia , Ducci Matthias 
Published: January 2010

AbstractIn diesem Beitrag wird das Karlsruher Projekt „Forsche Schülerinnen forschen“ vorgestellt. Ziel dieses Programms ist es, das naturwissenschaftlich‐technische Interesse junger Frauen im Alter von 13 bis 19 Jahren zu fördern. Die Maßnahmen umfassen Laborkurse mit chemischen und physikalischen Inhalten, Feriencamps mit dem Themenschwerpunkt Bionik sowie berufsberatende Maßnahmen.
The Centenary of the Glass Electrode
Authors: Piosik Romuald , Peper Renate , Jansen Walter 
Published: January 2010

AbstractDieser Beitrag befasst sich mit der Geschichte der Erfindung der Glaselektrode durch Fritz Haber und Zygmunt Klemensiewicz vor 100 Jahren. Wesentliche Vorarbeiten gehen auf Max Cremer zurück, der 1906 beobachtete, dass an Glasmembranen in Abhängigkeit von der Acidität der inneren bzw. äußeren Lösung eine Spannung wie bei einer galvanischen Zelle besteht. Haber und Klemensiewicz, die die Arbeit von Cremer kannten, entwickelten daraufhin das eigentliche Glaselektroden‐System und führten damit Säure/Base‐Titrationen durch.
An Instructional Concept for Introducing the Solubility Product in the Upper Secondary School System (Gymnasium)
Authors: Pfangert‐Becker Ursula 
Published: January 2010

AbstractAn einem Unterrichtsbeispiel aus der Sekundarstufe II soll aufgezeigt werden, wie Schüler durch Verknüpfen von experimentellen Untersuchungen und deklarativem wie vernetzendem Wissen Erkenntnisse zum Ausfallen und Auflösen von Niederschlägen gewinnen.
A randomized phase 2 study of etaracizumab, a monoclonal antibody against integrin αvβ3, ± dacarbazine in patients with stage IV metastatic melanoma
Authors: Hersey Peter , Sosman Jeffrey , O'Day Steven , Richards Jon , Bedikian Agop , Gonzalez Rene , Sharfman William , Weber Robert , Logan Theodore , Buzoianu Manuela , Hammershaimb Luz , Kirkwood John M. 
Published: January 2010

AbstractBACKGROUND:The alpha v beta 3 (αvβ3) integrin is involved in intracellular signaling regulating cell proliferation, migration, and differentiation and is important for tumor‐induced angiogenesis.METHODS:This phase 2, randomized, open‐label, 2‐arm study was designed to capture safety data and evaluate the antitumor efficacy of etaracizumab (Abegrin), an IgG1 humanized monoclonal antibody against the αvβ3 integrin, in patients with previously untreated metastatic melanoma. The objective was to evaluate whether etaracizumab ± dacarbazine had sufficient clinical activity to warrant further study in a phase 3 clinical trial.RESULTS:One hundred twelve patients were randomized to receive etaracizumab alone (N = 57) or etaracizumab + dacarbazine (N = 55). Safety of etaracizumab ± dacarbazine was acceptable with infusion‐related, gastrointestinal, and metabolic reactions being the most common adverse events (AEs). The majority of AEs were grade 1 or 2 in severity in both study arms; most events were not considered serious, except for cardiovascular (myocardial infarction, atrial fibrillation) and thromboembolic events, which occurred in 3 and 5 patients, respectively. None of the patients in the etaracizumab‐alone study arm and 12.7% of patients in the etaracizumab + dacarbazine study arm achieved an objective response. The median duration of objective response in the etaracizumab + dacarbazine study arm was 4.2 months. Stable disease rate, time to progression (TTP), and progression‐free survival (PFS) appeared to be similar between the 2 treatment arms. Stable disease occurred in 45.6% of patients in the etaracizumab‐alone study arm and 40.0% of patients in the etaracizumab + dacarbazine study arm. Median TTP and median PFS were both 1.8 months in the etaracizumab‐alone study arm and 2.5 and 2.6 months in the etaracizumab + dacarbazine study arm, respectively. Median overall survival was 12.6 months in the etaracizumab‐alone study arm and 9.4 months in the etaracizumab + dacarbazine study arm.CONCLUSIONS:The survival results in both treatment arms of this study were considered unlikely to result in clinically meaningful improvement over dacarbazine alone. Cancer 2010. © 2010 American Cancer Society.
Five‐year lung cancer survival
Authors: Wang Tina , Nelson Rebecca A. , Bogardus Alicia , Grannis Frederic W. 
Published: January 2010

AbstractBACKGROUND:The core strategy of American College of Chest Physicians lung cancer guidelines is identification of the earliest symptoms of lung cancer and the immediate initiation of diagnosis and treatment. In the absence of screening, most symptomatic lung cancer is discovered at advanced stages, with the goal of long‐term survival entirely dependent on effective treatment of stage III and IV lung cancer.METHODS:In a retrospective review, all patients diagnosed with stage IIIA, IIIB, and IV nonsmall cell lung cancer (NSCLC) between the years 1986 and 2001 at City of Hope National Medical Center who survived 5 years or longer were analyzed to identify parameters that might predict long‐term survival.RESULTS:Of 846 patients presenting with stage III or IV disease, 56 (6.6%) survived 5 years or longer. Sixteen patients died of primary tumor progression beyond 5 years. Two 5‐year survivors died of second tobacco‐caused neoplasms, and 16 died from medical conditions potentially related to prior treatment. A substantial majority of survivors were from specific pathologic subsets including: 1) resectable N2 disease (n = 17, 30.4%), 2) multiple lung tumors (n = 7, 12.5%), 3) T3N0 (n = 5, 8.1%), and 4) single site distant metastasis (n = 8, 14.2%).CONCLUSIONS:Despite aggressive multimodality therapy, 5‐year survival in patients with advanced stage NSCLC was very poor and limited to small pathological subsets. Patients with advanced stage NSCLC who did not belong to 1 of these subsets had a small chance of long‐term survival. Cancer 2010. © 2010 American Cancer Society.
Pathogenesis of osteoblastic bone metastases from prostate cancer
Authors: Ibrahim Toni , Flamini Emanuela , Mercatali Laura , Sacanna Emanuele , Serra Patrizia , Amadori Dino 
Published: January 2010

AbstractProstate cancer is the second leading cause of cancer‐related death in men. A typical feature of this disease is its ability to metastasize to bone. It is mainly osteosclerotic, and is caused by a relative excess of osteoblast activity, leading to an abnormal bone formation. Bone metastases are the result of a complex series of steps that are not yet fully understood and depend on dynamic crosstalk between metastatic cancer cells, cellular components of the bone marrow microenvironment, and bone matrix (osteoblasts and osteoclasts). Prostate cancer cells from primary tissue undergo an epithelial‐mesenchymal transition to disseminate and acquire a bone‐like phenotype to metastasize in bone tissue. This review discusses the biological processes and the molecules involved in the progression of bone metastases. Here we focus on the routes of osteoblast differentiation and activation, the crosstalk between bone cells and tumor cells, and the molecules involved in these processes that are expressed by both osteoblasts and tumor cells. Furthermore, this review deals with the recently elucidated role of osteoclasts in prostate cancer bone metastases. Certainly, to better understand the underlying mechanisms of bone metastasis and so improve targeted bone therapies, further studies are warranted to shed light on the probable role of the premetastatic niche and the involvement of cancer stem cells. Cancer 2010. © 2010 American Cancer Society.
Phase 1 pharmacokinetic and drug‐interaction study of dasatinib in patients with advanced solid tumors
Authors: Johnson Faye M. , Agrawal Shruti , Burris Howard , Rosen Lee , Dhillon Navneet , Hong David , Blackwood‐Chirchir Anne , Luo Feng R. , Sy Oumar , Kaul Sanjeev , Chiappori Alberto A. 
Published: January 2010

AbstractBACKGROUND:The recently developed the Src and Abelson (Abl) kinase inhibitor dasatinib has antitumor effects in epithelial and mesenchymal tumors. Preclinical data have indicated that dasatinib is metabolized primarily through cytochrome P450 3A4 (CYP3A4) and may cause QT prolongation. In light of its improved tolerability, the authors were interested in the safety of a once‐daily dasatinib regimen.METHODS:The authors conducted a phase 1 trial of dasatinib in 29 patients with advanced solid tumors. Segment 1 of the trial was short term and sequential and was designed to determine whether the coadministration of the potent CYP3A4 inhibitor ketoconazole had an effect on the pharmacokinetics of dasatinib. Segment 2 was designed to evaluate the safety of dasatinib as dosing was increased. QT intervals were monitored closely in both segments. Efficacy was assessed in Segment 2 using both positron emission tomography and computed tomography.RESULTS:Hematologic toxicities were markedly less than those observed in patients with leukemia, whereas nonhematologic toxicities were similar. The authors determined that the maximum recommended dose was 180 mg once daily based on the incidence of pleural effusion. Coadministration of ketoconazole led to a marked increase in dasatinib exposure, which was correlated with an increase in corrected QT (QTc) values of approximately 6 msec. No adverse cardiac events were observed.CONCLUSIONS:The dose‐limiting toxic effect for dasatinib was pleural effusion. The pharmacokinetic and cardiac studies indicated that coadministration of dasatinib with potent CYP3A4 inhibitors or agents that prolong the QTc interval should be avoided if possible. Close monitoring for toxicity and dose reduction should be considered if the coadministration of such agents cannot be avoided. Cancer 2010. © 2010 American Cancer Society.
Prediction of pathologic fracture risk of the femur after combined modality treatment of soft tissue sarcoma of the thigh
Authors: Gortzak Yair , Lockwood Gina A. , Mahendra Ashish , Wang Ying , Chung Peter W. M. , Catton Charles N. , O'Sullivan Brian , Deheshi Benjamin M. , Wunder Jay S. , Ferguson Peter C. 
Published: January 2010

AbstractBACKGROUND:The objective of the current study was to formulate a scoring system to enable decision making for prophylactic stabilization of the femur after surgical resection of a soft tissue sarcoma (STS) of the thigh.METHODS:A logistic regression model was developed using patient variables collected from a prospectively collected database. The study group included 22 patients who developed a radiation‐related pathological fracture of the femur after surgery and radiotherapy for an STS of the thigh. The control group of 79 patients received similar treatment but did not sustain a fracture. No patients received chemotherapy. The mean follow‐up was 8.6 years. The variables examined were age, gender, tumor size, radiation dose (low [50 grays (Gy)] vs high [≥60 Gy]), extent of periosteal stripping (<10 cm, 10‐20 cm, and >20 cm), and thigh compartment involvement (posterior, adductor, anterior or other [ie, abductors and groin]).RESULTS:On the basis of an optimal regression model, the ability to predict radiation–associated fracture risk was 91% sensitive and 81% specific. The area under the receiver operating characteristic curve was 0.9, which supports this model as a very accurate predictor of fracture risk.CONCLUSIONS:Radiation‐related fractures of the femur after combined surgery and radiotherapy for STS are uncommon, but are difficult to manage and their nonunion rate is extremely high. The results of the current study suggest that it is possible to predict radiation‐associated pathological fracture risk using patient and treatment variables with high sensitivity and specificity. This would allow for the identification of high‐risk patients and treatment with either close follow‐up or prophylactic intramedullary nail stabilization. The presentation of this model as a nomogram will facilitate its clinical use. Cancer 2010. © 2010 American Cancer Society.
Pelvic lymph node F‐18 fluorodeoxyglucose uptake as a prognostic biomarker in newly diagnosed patients with locally advanced cervical cancer
Authors: Kidd Elizabeth A. , Siegel Barry A. , Dehdashti Farrokh , Grigsby Perry W. 
Published: January 2010

AbstractBACKGROUND:The objective of the current study was to evaluate the prognostic significance of the maximum standardized uptake value (SUVmax) of F‐18 fluorodeoxyglucose (FDG) as measured by positron emission tomography (PET) in pelvic lymph nodes in patients with cervical cancer.METHODS:The authors studied cervical cancer patients with pelvic lymph node metastasis, as evidenced on FDG‐PET, who were treated between November 2003 and October 2008. The maximum dimension and SUVmaxfor the most FDG‐avid pelvic lymph node (SUVPLN) and the SUVmaxof the primary cervical tumor (SUVcervix) were recorded from the FDG‐PET/computed tomography (CT) scan. The SUVPLNwas analyzed for its association with treatment response, pelvic disease recurrence, disease‐specific survival, and overall survival.RESULTS:The population was comprised of 83 women with International Federation of Gynecology and Obstetrics (FIGO) stages IB1 to IIIB cervical cancer. The average SUVPLNwas 6.9 (range, 2.1‐33.0), whereas the average SUVcervixwas 14.0 (range, 3.2‐38.4). The SUVcervixand SUVPLNwere found to be weakly correlated (correlation coefficient [R2] = 0.301). The average size of the pelvic lymph nodes was 2.1 cm (range, 0.6‐7.9 cm), and was also found to be only weakly associated with the SUVPLN(R2= 0.225). The SUVPLNwas found to be correlated with an increased risk of persistent disease after treatment (P= .0025), specifically within the pelvic lymph node region (P= .0003). The SUVPLNwas found to be predictive of an increased risk of ever developing pelvic disease recurrence (P= .0035). Patients with a higher SUVPLNwere found to have significantly worse disease‐specific (P= .0230) and overall survival (P= .0378) using Kaplan‒Meier evaluation. A Cox proportional hazards model for the risk of pelvic disease recurrence was performed including SUVPLN,patient age, and tumor stage, and found only an increased SUVPLNto be an independent predictor.CONCLUSIONS:SUVPLNis a prognostic biomarker, predicting treatment response, pelvic recurrence risk, and disease‐specific survival in patients with cervical cancer. Cancer 2010. © 2010 American Cancer Society.
Microscopic Insights into Methane Activation and Related Processes on Pt/Ceria Model Catalysts
Authors: Lykhach Yaroslava , Staudt Thorsten , Lorenz Michael Peter Andreas , Streber Regine , Bayer Andreas , Steinrück Hans‐Peter , Libuda Jörg 
Published: January 2010

AbstractCeria‐based supported noble‐metal catalysts release oxygen, which may help to reduce the formation of carbonaceous residues, for example during hydrocarbon reforming. To gain insight into the microscopic origins of these effects, a model study is performed under ultrahigh‐vacuum conditions using single‐crystal‐based supported model catalysts. The model systems are based on ordered CeO2(111) films on Cu(111), on which Pt nanoparticles are grown by physical vapor deposition. The growth and structure of the surfaces are characterized by means of scanning tunneling microscopy, and the electronic structure and reactivity are probed by X‐ray photoelectron spectroscopy. Specifically, it is shown that the fully oxidized CeO2 thin films undergo slight reduction upon Pt deposition (CeO1.99). This effect is enhanced upon annealing (CeO1.96), thus indicating facile oxygen release and reverse spillover. The model system is structurally stable up to temperatures exceeding 700 K. The activation of methane is investigated using high‐kinetic‐energy CH4 (0.83 eV), generated by a supersonic molecular beam. It is shown that dehydrogenation occurs under rapid formation of CH or C species without detectable amounts of CH3 being formed, even at low temperatures (100 K). The released hydrogen spills over to the CeO2 support, which leads to the formation of OH groups. At 200 K and above, the OH groups start to decompose leaving additional Ce3+ centers behind (CeO1.97–1.94). At up to 700 K, carbon deposits are quantitatively removed by reaction with oxygen, which is supplied by reverse spillover from the CeO2 film, thus leading to substantial reduction of the support (∼CeO1.90–1.85).
Orientational Analysis of Dodecanethiol and p‐Nitrothiophenol SAMs on Metals with Polarisation‐Dependent SFG Spectroscopy
Authors: Cecchet Francesca , Lis Dan , Guthmuller Julien , Champagne Benoît , Caudano Yves , Silien Christophe , Addin Mani Alaa , Thiry Paul A. , Peremans André 
Published: January 2010

AbstractPolarisation‐dependent sum frequency generation (SFG) spectroscopy is used to investigate the orientation of molecules on metallic surfaces. In particular, self‐assembled monolayers (SAMs) of dodecanethiol (DDT) and of p‐nitrothiophenol (p‐NTP), grown on Pt and on Au, have been chosen as models to highlight the ability of combining ppp and ssp polarisations sets (representing the polarisation of the involved beams in the conventional order of SFG, Vis and IR beam) to infer orientational information at metallic interfaces. Indeed, using only the ppp set of data, as it is usually done for metallic surfaces, is not sufficient to determine the full molecular orientation. We show here that simply combining ppp and ssp polarisations enables both the tilt and rotation angles of methyl groups in DDT SAMs to be determined. Moreover, for p‐NTP, while the SFG active vibrations detected with the ppp polarisation alone provide no orientational information, however, the combination with ssp spectra enables to retrieve the tilt angle of the p‐NTP 1,4 axis. Though orientational information obtained by polarisation‐dependent measurements has been extensively used at insulating interfaces, we report here their first application to metallic surfaces.
Motherless rats show deficits in maternal behavior towards fostered pups
Authors: Palombo Daniela J. , Nowoslawski Michael , Fleming Alison S. 
Published: January 2010

AbstractComplete maternal deprivation in rats, through artificial rearing (AR), produces deficits in subsequent maternal behavior of the offspring. These deficits are partially reversed when isolated pups are provided with additional tactile stimulation designed to simulate maternal licking (e.g., Gonzalez et al. [2001] Developmental Psychobiology, 38, 11–32). These findings highlight the importance of the early maternal environment in subsequent development. However, given the possibility that prenatal environments may differ between AR and maternally reared (MR) offspring, the deficits in the behavior of AR mothers may be driven by the characteristics of their pups derived from the effects of an altered prenatal environment. Hence differences in the neonatal pups of AR mothers may produce the alterations in the AR maternal behavior. To rule out this possibility, we employed a fostering paradigm where AR and MR mothers received cross‐fostered mother‐reared pups. AR mothers showed the same level of deficits in maternal behavior towards MR foster pups as they do with their own pups and these deficits were partially reversed with additional tactile stimulation. Hence, maternal behavior deficits reported in mothers who had been reared in isolation are due primarily to the direct effects of the earlier experience on mechanisms regulating their maternal behavior and not to the effects on their offspring. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:142–148, 2010