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► The low temperature pulsed plasma nitrided layer of 316 SS was studied. ► The plastic deformation induced in the austenite due to nitriding is characterized by EBSD at different ...depths (i.e., nitrogen concentration). ► Nanomechanical properties of the nitride layer was investigated by nanoindentation at different depths (i.e., nitrogen concentration). ► High hardness, high nitrogen concentration and high dislocation density is detected in the nitride layer. ► The hardness and nitrogen concentration decreased sharply beyond the nitride layer.
Pulsed plasma nitriding (PPN) treatment is one of the new processes to improve the surface hardness and tribology behavior of austenitic stainless steels. Through low temperature treatment (<440
°C), it is possible to obtain unique combinations of wear and corrosion properties. Such a combination is achieved through the formation of a so-called “extended austenite phase”. These surface layers are often also referred to as S-phase, m-phase or γ-phase. In this work, nitrided layers on austenitic stainless steels AISI 316L (SS316L) were examined by means of a nanoindentation method at different loads. Additionally, the mechanical properties of the S-phase at different depths were studied. Electron back-scatter diffraction (EBSD) examination of the layer showed a high amount of plasticity induced in the layer during its formation. XRD results confirmed the formation of the S-phase, and no deleterious CrN phase was detected.
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► Plasma nitride layer of 316 SS was studied by electrochemical nanoindentation. ► H effect on mechanical properties of the substrate and nitride layer was studied. ► H increases the ...hardness of 316 SS and has opposite effect on the nitride layer. ► The H induced softening is advantageous for controlling the H embrittlement. ► The H induced softening is dependent on the N concentration.
In this work, the nitrided layer on austenitic AISI 316L stainless steels were examined by means of in situ electrochemical nanoindentation, and the effect of electrochemically charged hydrogen on the mechanical properties were investigated. By using this method, changes in the mechanical properties due to the absorption of atomic hydrogen at different nitride layer depths have been traced. One important finding is that hydrogen charging of the nitriding layer can soften the layer and reduce the layer hardness, and the reduction of the nitrogen concentration in the nitride layer reduces this softening effect.
Reactions of Pd2Cl2(μ-dppm)2 with RMgX (R = Me, Et, Bu, Ph, C6H4Me-4) at low temperature, followed by addition of CBr4 and excess NH4PF6 or 1 equiv of TlPF6, provided halide-bridged organopalladium ...A-frame complexes of the form Pd2R2(μ-X)(μ-dppm)2PF6. Mixed metal complexes were obtained similarly starting from PdPtCl2(μ-dppm)2. Unsymmetrical A-frames of the type Pd2(C6H2Me3-2,4,6)R(μ-Cl)(μ-dppm)2+ were generated by reaction of Pd(C6H2Me3-2,4,6)(dppm)2+ (obtained by treatment of PdCl2(cod) with mesitylmagnesium bromide at low temperature, followed by 2 equiv of dppm) with Pd2R2(μ-Cl)2(AsPh3)2. The organopalladium A-frames did not react readily with CO, but the corresponding acyl derivatives Pd2(COR)2(μ-Cl)(μ-dppm)2PF6 were produced by carbonylation of Pd2R2(μ-Cl)2(AsPh3)2 followed by addition of dppm (R = Me, Et, Bn). Thermal decomposition of Pd2(CH2Ph)2(μ-Cl)(μ-dppm)2Cl was found to be first order in A-frame and resulted in quantitative formation of Pd2Cl2(μ-dppm)2 and 1,2-diphenylethane. The methyl and aryl complexes underwent both reductive elimination and hydrogen abstraction reactions. Pd2Et2(μ-Br)(μ-dppm)2PF6 decomposed by β-hydride elimination and subsequent reductive elimination to yield ethene and ethane, whereas the butyl derivative gave both 1- and 2-butene. Acetic acid was formed when Pd2(COMe)2(μ-Cl)(μ-dppm)2PF6 was heated in dmso-d 6 solution, but decarbonylation was the predominant process in dioxane. The molecular structures of Pd2(CH2Ph)2(μ-Br)(μ-dppm)2PF6·H2O,2C6H6 and Pd2Cl2(μ-Cl)(μ-dppm)2OH·0.5(CH3)2CO are also described.
In this randomized trial involving patients with chronic hepatitis C who were also infected with the human immunodeficiency virus (HIV), peginterferon alfa-2a plus ribavirin was more effective than ...interferon alfa-2a plus ribavirin or peginterferon alfa-2a plus placebo (rates of sustained virologic response, 40 percent, 12 percent, and 20 percent, respectively).
The rates of response were not as high as in previous studies involving HIV-negative patients.
Potent antiretroviral therapy has reduced the morbidity and mortality associated with untreated human immunodeficiency virus (HIV) infection.
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At the same time, the pattern of morbidity and mortality among HIV-infected persons has shifted, and clinicians responsible for the care of HIV-infected persons have been confronted with new challenges. Complications associated with concurrent hepatitis C virus (HCV) infection have emerged as one of the most frequent and complex issues in the care of patients with HIV infection and the acquired immunodeficiency syndrome (AIDS).
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The current standard of care for chronic infection with HCV in persons without other infections is pegylated . . .
Reaction of PdClMe(cod) with MeO2CC⋮CCO2Me occurs in two steps, namely, insertion of the alkyne into the Pd−Me bond followed by migratory insertion of one of the double bonds of the coordinated ...cyclooctadiene into the Pd−alkenyl bond thus formed. The resulting chloride-bridged, cyclooctenyl complex was converted to Pd(acac){η1,η2-C8H12C(CO2Me)CMe(CO2Me)}, 2a, which was characterized crystallographically. The molecular structure revealed that each insertion took place in a cis manner. Reactions of PdCl2(cod) with a range of nucleophiles were performed, which gave analogous chloride-bridged, cyclooctenylpalladium dimers, 1, which could be converted to their acetylacetonate derivatives, 2. The solid-state structure of the methoxy complex Pd(acac)(η1,η2-C8H12OMe), 2b, obtained by reaction of PdCl2(cod) with NaOMe followed by Ag(acac), was determined. This showed that exo attack of the OMe group occurred. In contrast, the structure of the phenyl derivative Pd(acac)(η1,η2-C8H12Ph), 2e, produced by treatment of PdCl2(cod) with Ph4Sn followed by Ag(acac), indicated that the phenyl group added in an endo fashion, presumably via a phenylpalladium intermediate of the type PdClPh(cod). With the larger mesityl group, the complex PdCl(C6H2Me3)(cod) could be isolated. Each of the complexes was fully characterized by 1H and 13C{1H} NMR spectroscopy, and the appearance of the CHPd signal was used to distinguish between the exo and endo isomers. On the basis of the crystallographic and NMR data, it was deduced that the organometallic reagents ArMgX (Ar = Ph, 2-MeC6H4, 2,4,6-Me3C6H2), Ph4Sn, and (4-MeC6H4)2Hg generate the endo products by initial attack at the metal. In contrast, reactions with NaOR (R = Me, Et), NaCH(CO2Me)2, AgOAc, and Et2NH proceed by direct attack of the nucleophile at the coordinated double bond to give the exo products.
Inappropriate Medications for Elderly Patients Chutka, Darryl S.; Takahashi, Paul Y.; Hoel, Robert W.
Mayo Clinic proceedings,
2004, 2004-Jan, 2004-1-00, 20040101, Letnik:
79, Številka:
1
Journal Article
Recenzirano
The use of medications is common in elderly persons, and this population has the highest risk of medication-related problems. Elderly persons are more susceptible to the effects of various ...medications for a number of reasons. It is well known that polypharmacy is one of the most serious problems in caring for elderly persons; however, many of these patients continue to receive medications that have an increased risk of causing harm. In 1991, an important article was published about inappropriate medication use in the elderly population. This article raised awareness of the problem and presented explicit criteria for determining which medications were inappropriate for elderly patients residing in long-term care facilities. This list of drugs is still used for evaluating medications taken by elderly persons and for determining whether satisfactory prescribing practices are being used. We reviewed the medications described as inappropriate for elderly persons and searched the scientific literature to determine whether evidence exists to defend or refute the labeling of particular drugs. At times, evidence was difficult to find, and many of the original studies were dated. For most medications listed as inappropriate, we found evidence to support these designations.
The purpose of this study was to estimate the extent of potential antidepressant overprescribing in a geographically defined U.S. population, and to determine the indications and factors that account ...for it. We conducted a cohort study of new antidepressant prescriptions for elderly residents of Olmsted County, Minnesota, 2005‐2012, using the Rochester Epidemiology Project medical records‐linkage system. Indications for antidepressants were ed from health records for all cohort members. Potential antidepressant overprescribing was defined based on regulatory approval, the level of evidence identified from a standardized drug information database, and multidisciplinary expert review. Predictors of potential antidepressant overprescribing were investigated using logistic regression models, stratified by general antidepressant indication (general medical indication, specific psychiatric diagnosis, and non‐specific psychiatric symptoms). Potential antidepressant overprescribing occurred in 24% of 3199 incident antidepressant prescriptions during the study period, and involved primarily newer antidepressants that were prescribed for non‐specific psychiatric symptoms and subthreshold diagnoses. Potential antidepressant overprescribing was associated with nursing home residence, having a higher number of comorbid medical conditions and outpatient prescribers, taking more concomitant medications, having greater use of urgent or acute care services in the year preceding the index antidepressant prescription, and being prescribed antidepressants via telephone, e‐mail, or patient portal. In conclusion, potential antidepressant overprescribing occurred in elderly persons and involved mainly newer antidepressants used for non‐specific psychiatric symptoms and subthreshold diagnoses, and was associated with indicators of higher clinical complexity or severity and with prescribing without face‐to‐face patient contact.
Calcineurin inhibitor (CNI)-induced nephrotoxicity is a feared adverse effect after heart transplantation (HTx). In patients with advanced renal failure we performed an overnight conversion from ...cyclosporine (CsA) to everolimus within the first year after HTx and compared changes in renal function to a similar switch performed in a group of long-term HTx survivors with 24-month follow up.
Sixteen HTx recipients (Group 1), including 5 patients undergoing dialysis, were switched overnight from CsA to everolimus at 5.5 (range 1.3 to 8.5) months post-operatively, whereas 15 patients completed 24 months of follow-up. Fifteen long-term survivors (Group 2) were recruited at 96 (58 to 148) months post-HTx. Due to 3 withdrawals and 2 deaths, 10 of these 15 patients remained available for follow-up assessment.
In Group 1 patients, creatinine level improved from 211 (186 to 263) to 112 (98 to 140) mumol/liter and estimated glomerular filtration rate (eGFR) from 29 (20 to 35) to 62 (43 to 69) ml/min/1.73 m(2) (p < 0.001). In Group 2, creatinine decreased from 227 (188 to 255) to 193 (150 to 250) micromol/liter (p = 0.299), and eGFR increased from 26 (21 to 31) to 28 (22 to 35) ml/min/1.73 m(2) (p = 0.225). Four cellular rejections were treated successfully in Group 1. All together, 24 adverse events occurred.
These preliminary data are the first to suggest that the improvement in renal function after switching to CNI-free everolimus treatment has the greatest potential within the first year post-HTx. While we await randomized, controlled trials, it appears that conversion can be performed with acceptable safety in selected patients.
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