An Evaluation of the Fe-N Phase Diagram Considering Long-Range Order of N Atoms in γ'-Fe4N1-x and ε-Fe2N1-z

The chemical potential of nitrogen was described as a function of nitrogen content for the Fe-N phases α-Fe[N], γ'-Fe4N1-x, and ε-Fe2N1-z. For α-Fe[N], an ideal, random distribution of the nitrogen atoms over the octahedral interstices of the bcc iron lattice was assumed; for γ'-Fe4N1-x and ε-Fe2N1-z, the occurrence of a long-range ordered distribution of the nitrogen atoms over the octahedral interstices of the close packed iron sublattices (fcc and hcp, respectively) was taken into account. The theoretical expressions were fitted to nitrogen-absorption isotherm data for the three Fe-N phases. The α/α + γ', α + γ'/γ', γ'/γ' + ε, and γ' + ε/ε phase boundaries in the Fe-N phase diagram were calculated from combining the quantitative descriptions for the absorption isotherms with the known composition of NH3/H2 gas mixtures in equilibrium with coexisting α and γ' phases and in equilibrium with coexisting γ' and ε phases. Comparison of the present phase boundaries with experimental data and previously calculated phase boundaries showed a major improvement as compared to the previously calculated Fe-N phase diagrams, where long-range order for the nitrogen atoms in the γ' and ε phases was not accounted for

Quality of care for hypertension in the United States

BACKGROUND: Despite heavy recent emphasis on blood pressure (BP) control, many patients fail to meet widely accepted goals. While access and adherence to therapy certainly play a role, another potential explanation is poor quality of essential care processes (QC). Yet little is known about the relationship between QC and BP control. METHODS: We assessed QC in 12 U.S. communities by reviewing the medical records of a randomly selected group of patients for the two years preceding our study. We included patients with either a diagnosis of hypertension or two visits with BPs of ≥140/90 in their medical records. We used 28 process indicators based on explicit evidence to assess QC. The indicators covered a broad spectrum of care and were developed through a modified Delphi method. We considered patients who received all indicated care to have optimal QC. We defined control of hypertension as BP < 140/90 in the most recent reading. RESULTS: Of 1,953 hypertensive patients, only 57% received optimal care and 42% had controlled hypertension. Patients who had received optimal care were more likely to have their BP under control at the end of the study (45% vs. 35%, p = .0006). Patients were more likely to receive optimal care if they were over age 50 (76% vs. 63%, p < .0001), had diabetes (77% vs. 71%, p = .0038), coronary artery disease (87% vs. 69%, p < .0001), or hyperlipidemia (80% vs. 68%, p < .0001), and did not smoke (73% vs. 66%, p = .0005). CONCLUSIONS: Higher QC for hypertensive patients is associated with better BP control. Younger patients without cardiac risk factors are at greatest risk for poor care. Quality measurement systems like the one presented in this study can guide future quality improvement efforts

"Zementfreie Modular Endoprothesen Ergebnisse und Komplikationen"

"Zementfreie Modular Endoprothesen Ergebnisse und Komplikationen

The effect of quadriceps excision on functional results after distal femoral resection and prosthetic replacement of bone tumors

none7Although resection and reconstruction with a prosthesis is an accepted form of treatment for tumors of the distal femur, minimal effort has been made to correlate the functional result with the degree of adjacent muscle excision. From 1983 to 1986, 65 patients had distal femoral resection and prosthetic reconstruction. Ten patients had only the vastus intermedius excised (Group A), 30 patients had excision of the vastus intermedius plus either the vastus medialis or lateralis (Group B), nine patients had only the rectus femoris spared (Group C), and 16 patients had the entire quadriceps excised or conversion of the previous arthrodesis (Group D). Based on the rating system of the Musculoskeletal Tumor Society, satisfactory results were obtained in 70% of Group A patients (30% excellent and 40% good), with no poor results. In group B, 80% had good or excellent results and 7% poor results. In Group C, 78% of the patients had good results but no excellent results, whereas Group D had only 50% satisfactory results. The parameters that most often led to functional impairment were restricted motion and inadequate extensor powers. Muscle transfers, however, (flexors to extensors) were effective only in Group C patients. With proper technique and prosthetic design, satisfactory results can be achieved after distal femoral resection and prosthetic reconstruction, even after extensive quadriceps excision.noneCapanna R; Ruggieri P; Biagini R; Ferraro A; DeCristofaro R; McDonald D; Campanacci MCapanna, R; Ruggieri, Pietro; Biagini, R; Ferraro, A; Decristofaro, R; Mcdonald, D; Campanacci, M

Transcutaneous CO2 versus end-tidal CO2 in neonates and infants undergoing surgery: a prospective study

Arvind Chandrakantan,1 Ronald Jasiewicz,2 Ruth A Reinsel,3 Kseniya Khmara,2 Jonathan Mintzer,4 Joseph D DeCristofaro,4 Zvi Jacob,2 Peggy Seidman51Department of Anesthesiology &amp; Pediatrics, Texas Children&rsquo;s Hospital, Houston, TX, USA; 2Department of Anesthesiology, Stony Brook University Hospital, Stony Brook, NY, USA; 3Department of Neurology, Stony Brook University Hospital, Stony Brook, NY, USA; 4Department of Neonatology &amp; Pediatrics, Stony Brook University Hospital, Stony Brook, NY, USA; 5Department of Anesthesiology &amp; Pediatrics, UH Rainbow Babies and Children&rsquo;s Hospital, Cleveland, OH, USAAim: End-tidal CO2 (EtCO2) is the standard in operative care along with pulse oximetry for ventilation assessment. It is known to be less accurate in the infant population than in adults. Many neonatal intensive care units (NICU) have converted to utilizing transcutaneous CO2 (tcPCO2) monitoring. This study aimed to compare perioperative EtCO2 to tcPCO2 in the pediatric perioperative population specifically below 10 kg, which encompasses neonates and some infants.Methods: After IRB approval and parental written informed consent, we enrolled neonates and infants weighing less than 10 kg, who were scheduled for elective surgery with endotracheal tube under general anesthesia. PCO2 was monitored with EtCO2 and with tcPCO2. Venous blood gas (PvCO2) samples were drawn at the end of the anesthetic. We calculated a mean difference of EtCO2 minus PvCO2 (Delta EtCO2), and tcPCO2 minus PvCO2 (Delta tcPCO2) from end-of-case measurements. The mean differences in the NICU and non-NICU patients were compared by t-tests and Bland&ndash;Altman analysis.Results: Median age was 10.9 weeks, and median weight was 4.4 kg. NICU (n=6) and non-NICU (n=14) patients did not differ in PvCO2. Relative to the PvCO2, the Delta EtCO2 was much greater in the NICU compared to the non-NICU patients (&minus;28.1 versus &minus;9.8, t=3.912, 18 df, P=0.001). Delta tcPCO2 was close to zero in both groups. Although both measures obtained simultaneously in the same patients agreed moderately with each other (r =0.444, 18 df, P=0.05), Bland&ndash;Altman plots indicated that the mean difference (bias) in EtCO2 measurements differed significantly from zero (P&lt;0.05).Conclusions: EtCO2 underestimates PvCO2 values in neonates and infants under general anesthesia. TcPCO2 closely approximates venous blood gas values, in both the NICU and non-NICU samples. We, therefore, conclude that tcPCO2 is a more accurate measure of operative PvCO2 in infants, especially in NICU patients.Keywords: infant, newborn, end-tidal CO2, blood gas monitoring-transcutaneous, intensive care monitoring- neonatal, ASA monitoring standard

"Complications their Treatment and Outcome in 257 Cementless Megaprostheses"

"Complications their Treatment and Outcome in 257 Cementless Megaprostheses