4,485 research outputs found
Three-coordinate iron(II) expanded ring N-heterocyclic carbene complexes
A sterically demanding seven-membered expanded ring N-heterocyclic carbene (NHC) ligand allows access to rare examples of three-coordinate iron(II)-NHC complexes incorporating only halide coligands of the general formula [Fe(NHC)X 2 ] (NHC = 7-DiPP; X = Br (1) Cl (2)). Reducing the steric influence of the ancillary NHC ligand through modulation of the N-aryl substituents leads to either four- or three-coordinate complexes of the general formula [Fe(NHC)Br 2 (THF)] (3) or [Fe(NHC)Br 2 ] (4) (NHC = 7-Mes), dependent upon the solvent of recrystallization. The further reduction of NHC steric influence results in four-coordinate geometries at iron in the form of the dimeric species [Fe(NHC)Br(ÎŒ-Br)] 2 (5) or [Fe(NHC)Br 2 (THF)] (6) (NHC = SDiPP), again dependent upon the solvent of recrystallization. Compounds 1-6 have been analyzed by 1 H NMR spectroscopy, X-ray crystallography, elemental microanalysis, Mössbauer spectroscopy (for 1 and 3-5), and Evans method magnetic susceptibility. In addition to these measurements the three-coordinate species 1 and 4 have been further analyzed by SQUID magnetometry and CASSCF calculations, which show significant magnetic anisotropy that is extremely sensitive to the coordination geometry
Understanding jumping to conclusions in patients with persecutory delusions: working memory and intolerance of uncertainty
Background. Persecutory delusions are a key psychotic experience. A reasoning style known as âjumping to conclusionsâ (JTC) â limited information gathering before reaching certainty in decision making â has been identified as a contributory factor in the occurrence of delusions. The cognitive processes that underpin JTC need to be determined in order to develop effective interventions for delusions. In the current study two alternative perspectives were tested: that JTC partially results from impairment in information-processing capabilities and that JTC is a motivated strategy to avoid uncertainty.Method. A group of 123 patients with persistent persecutory delusions completed assessments of JTC (the 60:40 beads task), IQ, working memory, intolerance of uncertainty, and psychiatric symptoms. Patients showing JTC were compared with patients not showing JTC.Results. A total of 30 (24%) patients with delusions showed JTC. There were no differences between patients who did and did not jump to conclusions in overall psychopathology. Patients who jumped to conclusions had poorer working memory performance, lower IQ, lower intolerance of uncertainty and lower levels of worry.Working memory and worry independently predicted the presence of JTC.Conclusions. Hasty decision making in patients with delusions may partly arise from difficulties in keeping information in mind. Interventions for JTC are likely to benefit from addressing working memory performance, while in vivo techniques for patients with delusions will benefit from limiting the demands on working memory. The study provides little evidence for a contribution to JTC from top down motivational beliefs about uncertainty
Nutritive Value of the Crop Residues from bt-Corn Hybrids and Their Effects on Performance of Grazing Beef Cows
One non bt-corn hybrid (Pioneer 3489) and three btcorn hyrids (Pioneer 34RO7, Novartis NX6236, and Novartis N64-Z4) were planted in replicated 7.1-acre fields. After grain harvest, fields were stocked with 3 mature cows in midgestation to be strip-grazed as four paddocks over 126 days. Six similar cows were allotted to replicated drylots. All cows were fed hay as necessary to maintain a condition score of 5 on a 9-point scale. Cows were condition-scored biweekly and weighed monthly. Forage yield and weathering losses were determined by sampling one 4-m2 location per grazed or ungrazed paddock in each field with a minimum total of 2 locations of grazed or ungrazed forage per field. To measure forage selection during grazing, samples of grazed forage were collected from the rumen of one fistulated steer that grazed for 2 hours after ruminal evacuation. Non-bt-corn hybrids had greater (P\u3c.05) infestation of corn borers in the upper stalk, lower stalk and ear shank than bt-corn hybrids. However, there were no differences in grain yields or dropped grain between hybrids. Crop residue dry matter, organic matter and in vitro digestible dry matter yields at the initiation of grazing did not differ between corn hybrids. Dry matter, organic matter and in vitro digestible dry matter losses tended (P\u3c.10) to be greater from the NX6236 and N64-Z4 hybrids than from the 3489 and 34RO7 hybrids and were greater (P\u3c.05) from grazed than non-grazed areas of the fields. At the initiation of grazing, dry matter concentrations of the crop residues from the NX6236 and N64-Z4 hybrids tended to be lower than those from the 3489 and 34RO7 hybrids. Crop residues from the NX6236 and N64-74 hybrids had lower concentrations of acid detergent fiber (P\u3c.05) and acid detergent lignin (P=.07) and higher concentrations of in vitro digestible organic matter than the 3489 and 34RO7 hybrids. Over the grazing season, corn hybrid did not affect mean rates of change in forage composition. The concentration of in vitro digestible organic matter in forage selected by steers after two weeks of grazing did not differ. However, steers grazing corn crop residues consumed forage with higher (P\u3c.05) concentrations of neutral detergent fiber, acid detergent fiber, and acid detergent insoluble nitrogen than steers fed hay. The acid detergent fiber concentration of forage selected by steers grazing the 3489 and N64-Z4 hybrids was lower (P \u3c .05) than concentrations from the 34RO7 and NX6236 hybrids. In order to maintain similar body condition score changes, cows grazing crop residues from the 3489, 34RO7, NX6236, and N64-Z4 hybrids required 650, 628, 625, and 541 kg hay DM/cow compared with a hay requirement of 1447 kg hay DM/cow for cows maintained in a drylot
Antimatter production in proton-proton and heavy-ion collisions at ultrarelativistic energies
One of the striking features of particle production at high beam energies is
the near equal abundance of matter and antimatter in the central rapidity
region. In this paper we study how this symmetry is reached as the beam energy
is increased. In particular, we quantify explicitly the energy dependence of
the approach to matter/antimatter symmetry in proton-proton and in heavy-ion
collisions. Expectations are presented also for the production of more complex
forms of antimatter like antihypernuclei.Comment: 7 pages, 5 figure
Support Networks of Primary Caregivers Receiving Family Preservation Services: An Exploratory Study
Copyright 1994 Families International, Inc.The authors describe network characteristics and support resources from a clinical sample of 40
families. Data were obtained by family workers during the first two weeks of intervention. Case vignettes illustrate
the multiple uses to which this information was put. Implications for future research and practice are discussed
Transnational social capital: the socioâspatialities of civil society
Civil society remains a contested concept, but one that is widely embedded in global development processes. Transnationalism within civil society scholarship is often described dichotomously, either through hierarchical dependency relations or as a more amorphous networked global civil society. These two contrasting spatial imaginaries produce very particular ideas about how transnational relations contribute to civil society. Drawing on empirical material from research with civil society organizations in Barbados and Grenada, in this article I contend that civil society groups use forms of transnational social capital in their work. This does not, however, resonate with the horizontal relations associated with grassroots globalization or vertical chains of dependence. These social relations are imbued with power and agency and are entangled in situated historical, geographical and personal contexts. I conclude that the diverse transnational social relations that are part of civil society activity offer hope and possibilities for continued civil society action in these unexpected spatial arrangements
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First Report of NRG Oncology/Radiation Therapy Oncology Group 0622: A Phase 2 Trial of Samarium-153 Followed by Salvage Prostatic Fossa Irradiation in High-Risk Clinically Nonmetastatic Prostate Cancer After Radical Prostatectomy.
PURPOSE: To investigate the utility of 153Sm lexidronam (Quadramet) in the setting of men with prostate cancer status post radical prostatectomy who develop biochemical failure with no clinical evidence of osseous metastases.
PATIENTS AND METHODS: Trial NRG Oncology RTOG 0622 is a single-arm phase 2 trial that enrolled men with pT2-T4, N0-1, M0 prostate cancer status post radical prostatectomy, who meet at least 1 of these biochemical failure criteria: (1) prostate-specific antigen (PSA) \u3e 1.0 ng/mL; (2) PSA \u3e 0.2 ng/mL if Gleason score 9 to 10; or (3) PSA \u3e 0.2 ng/mL if N1. Patients received 153Sm (2.0 mCi/kg intravenously Ă 1) followed by salvage external beam radiation therapy (EBRT) to the prostatic fossa (64.8-70.2 Gy in 1.8-Gy daily fractions). No androgen deprivation therapy was allowed. The primary objective was PSA response within 12 weeks of receiving 153Sm. The secondary objectives were to: (1) assess the completion rate for the regimen of 153Sm and EBRT; (2) evaluate the hematologic toxicity and other adverse events (AEs) at 12 and 24 weeks; and (3) determine the freedom from progression rate at 2 years.
RESULTS: A total of 60 enrolled eligible patients were included in this analysis. Median follow-up was 3.97 years. A PSA response was achieved in 7 of 52 evaluable patients (13.5%), compared with the 25% hypothesized. The 2-year freedom from progression rate was 25.5% (95% confidence interval 14.4%-36.7%), and the biochemical failure rate was 64.4% (95% CI 50.5%-75.2%). Samarium-153 was well tolerated, with 16 (of 60) grade 3 to 4 hematologic AEs and no grade 5 hematologic AEs. Radiation therapy was also well tolerated, with no grade 3 to 5 acute radiation therapy-related AEs and 1 grade 3 to 4 and no grade 5 late radiation therapy-related AEs.
CONCLUSIONS: Trial NRG Oncology RTOG 0622 did not meet its primary endpoint of PSA response, although the regimen of 153Sm and salvage EBRT was well tolerated. Although the toxicity profile supports study of 153Sm in high-risk disease, it may not be beneficial in men receiving EBRT
On analytical tools for assessing the raindrop erosion of wind turbine blades
In renewable energy, wind capture has been expanding to now have one of the largest presences in the global green energy sector. With the drive to expand low carbon technologies; maintenance of the engineering components of wind turbines is crucial and in particular the monitoring of the leading edge of turbine blades which experience high impact velocities in service. Surface changes due to rain drop erosion can reduce energy conversion due to a loss of aerodynamic efficiency. This is one of the key areas of interest, as even small aerodynamic changes can lead to 2â3% loss in annual energy. Inspection methodologies of turbine blades are basic, involving an observation and high-definition photographs of the damage. Recent studies on the rain erosion of turbine blade materials show that this standard procedure often fails to characterise the loss of aerodynamic efficiency in these turbine blades in. With the industry moving in the direction of leading-edge profile samples, there is a consensus that whirling arm type test rigs are the most applicable testing regimes. Presently there is little overlap in the analysis used in different studies. This review considers various techniques which may be used to inspect and characterise the materials performance following exposure to rain drop erosion. These techniques will be evaluated based on their potential use within the industry. Findings conclude that a combination of techniques is optimal to analyse surface defects and that subsurface analysis is an important factor that must be considered in any investigation of long-term blade integrity
Synthesis of diaryl dithiocarbamate complexes of zinc and their uses as single source precursors for nanoscale ZnS
Diaryldithiocarbamate complexes, [Zn(S2CNAr2)2], have been prepared with a view to comparing their structures, reactivity and thermally-promoted degradation with respect to the well-studied dialkyl-derivatives. In the solid-state both [Zn{S2CN(p-tol)2}2] and [Zn{S2CN(p-anisyl)2}2] are monomeric with a distorted tetrahedral Zn(II) centre, but somewhat unexpectedly, the bulkier naphthyl-derivative [Zn{S2CN(2-nap)2}2]2 forms dimeric pairs with five-coordinate Zn(II) centres. Preliminary reactivity studies on [Zn{S2CN(p-tol)2}2] suggests that it binds amines and cyclic amines in a similar fashion to the dialkyl complexes and can achieve six-coordination as shown in the molecular structure of [Zn{S2CN(p-tol)2}2(2,2âČ-bipy)]. The thermal decomposition of [Zn{S2CN(p-tol)2}2] was studied in oleylamine solution by both heat-up and hot-injection methods. Nanorods of ZnS were produced in both cases with average dimensions of 17 Ă 2.1 nm and 11 Ă 3.5 nm respectively, being significantly shorter than those produced from [Zn(S2CNiBu2)2] under similar conditions. This is tentatively attributed to the differing rates of amine-exchange between diaryl- and dialkyl dithiocarbamate (DTC) complexes and/or their differing rates of DTC loss following amine-exchange. The solid-state decomposition of [Zn{S2CN(p-tol)2}2] has also been studied at 450 °C under argon affording irregular and large (10â300 ”m) sheet-like particles of wurtzite
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