The Rate of Precipitation of Copper Aluminide in the Silver Rich Silver-Copper-Aluminum Alloys

In order to determine the best annealing temperature at which to age-harden the alloys, hardness tests on speci­men annealed for different lengths of time at different temperatures were made.

A Study of the Effect of Oxygen on the Rate of Dissolution of Gold in Cyanide Solutions.

The accepted chemical reactions in the dissolution of gold by cyanide solutions require the presence of gold, cyanide, water, and oxygen. The importance of dissolved oxygen in cyanide solutions as a factor is recognized by those familiar with cyanidation. Manufacturers of cyanidation equipment realize the necessity of oxygen, as shown by the appliances they have developed which are attached to the agitators in order to saturate the cyanide solutions with air.

The Effect of Temperature on the Rate of Dissolution of Gold in Cyanide Solutions which have a Constant Oxygen Content.

Since the development of cyanidation into a highly efficient process for treating gold ores, many papers have been written on its various aspects. Although, there has been much work done on it, the chemistry of the reaction is not yet completely understood.

Assessments and Computational Simulations in Support of a Time-Varying Mass Flow Rate Measurement Technique for Pulsatile Gas Flow

This thesis covers the correction, and verification, development, and implementation of a computational fluid dynamics (CFD) model for an orifice plate meter. Past results were corrected and further expanded on with compressibility effects of acoustic waves being taken into account. One dynamic pressure difference transducer measures the time-varying differential pressure across the orifice meter. A dynamic absolute pressure measurement is also taken at the inlet of the orifice meter, along with a suitable temperature measurement of the mean flow gas. Together these three measurements allow for an incompressible CFD simulation (using a well-tested and robust model) for the cross-section independent time-varying mass flow rate through the orifice meter. The mean value of this incompressible mass flow rate is then corrected to match the mean of the measured flow rate( obtained from a Coriolis meter located up stream of the orifice meter). Even with the mean and compressibility corrections, significant differences in the measured mass flow rates at two orifice meters in a common flow stream were observed. This means that the compressibility effects associated with pulsatile gas flows is significant in the measurement of the time-varying mass flow rate. Future work (with the approach and initial runs covered here) will provide an indirect verification of the reported mass flow rate measurements.

Effects of a Beginning Judo Class on Heart Rate

We evaluated the heart rate responses of 15 adult and six child subjects to beginning judo class sessions. Heart rate responses were compared to cardiovascular intensity ranges recommended by the American College of Sports Medicine (ACSM). Heart rate responses of adults (n=15) averaged 70 percent of age-predicted maximum heart rate with a range of 96 beats/minute to 154 beats/minute. The heart rate responses of the children (n=6) averaged 68 percent of age-predicted maximum heart rate with a range of 133-161 beats/min. Our results show that judo is effective in elevating heart rate to levels recommended by the ACSM for appropriate periods of time to improve cardiovascular fitness.

Heart Rate Effects of Longboard Skateboarding

The longboard skateboard has a longer, and usually wider, deck than the standard skateboard to provide greater support for the rider during the higher speeds attained on this version of the skateboard. Fourteen volunteer subjects participated in downhill and uphill longboarding trials. Heart rates were monitored during both trials, and the downhill and uphill average heart rates were compared with resting heart rates and then compared with accepted intensity recommendations for health and fitness benefits. The study questions were: Does longboarding have an acute effect on heart rates? If so, will longboarding uphill and/or downhill cause heart rate changes to levels recommended to improve cardiorespiratory health and fitness? With these questions as guidance we developed four hypotheses. With beats/minute and average uphill heart rate of 167.8 beats/minute statistical analysis showed statistically significant p values < .0001 and each null hypothesis was rejected in favor of their respective research hypotheses. Based on average age and average resting heart rate, average age-predicted maximum heart rate was 193.2 beats/minute and heart rate reserve was 133.2 beats/minute. The average percentages of heart rate reserve for the downhill section (131.4 beats/minute) and uphill section )(167.8 beats/minute) were 54% and 81% respectively. Downhill heart rates are within moderate intensity levels, 40% to 60% of heart rate reserve, and uphill heart rates are within vigorous intensity levels, greater than 60% of heart rate reserve. These results indicate that longboarding can increase heart rate to suggested levels suggested by the American College of Sports Medicine for improving cardiovascular health and fitness.

Relation of heart rate recovery to psychological distress and quality of life in patients with chronic heart failure

BACKGROUND: Psychological distress, poor disease-specific quality of life (QoL), and reduction in vagally mediated early heart rate recovery (HRR) after exercise, all previously predicted morbidity and mortality in patients with chronic heart failure (CHF). We hypothesized lower HRR with greater psychological distress and poorer QoL in CHF. DESIGN: All assessments were made at the beginning of a comprehensive cardiac outpatient rehabilitation intervention program. METHODS: Fifty-six CHF patients (mean 58+/-12 years, 84% men) completed the Hospital Anxiety and Depression Scale and the Minnesota Living With Heart Failure Questionnaire. HRR was determined as the difference between HR at the end of exercise and 1 min after exercise termination (HRR-1). RESULTS: Elevated levels of anxiety symptoms (P=0.005) as well as decreased levels of the Minnesota Living With Heart Failure Questionnaire total (P = 0.025), physical (P=0.026), and emotional (P=0.017) QoL were independently associated with blunted HRR-1. Anxiety, total, physical, and emotional QoL explained 11.4, 8, 7.8, and 9.0%, respectively, of the variance after controlling for covariates. Depressed mood was not associated with HRR-1 (P=0.20). CONCLUSION: Increased psychological distress with regard to elevated anxiety symptoms and impaired QoL were independent correlates of reduced HRR-1 in patients with CHF. Reduced vagal tone might explain part of the adverse clinical outcome previously observed in CHF patients in relation to psychological distress and poor disease-specific QoL.

Heart rate recovery after exercise in chronic heart failure: Role of vital exhaustion and type D personality

OBJECTIVE: Vital exhaustion and type D personality previously predicted mortality and cardiac events in patients with chronic heart failure (CHF). Reduced heart rate recovery (HRR) also predicts morbidity and mortality in CHF. We hypothesized that elevated levels of vital exhaustion and type D personality are both associated with decreased HRR. METHODS: Fifty-one patients with CHF (mean age 58+/-12 years, 82% men) and left ventricular ejection fraction (LVEF) rate at the end of exercise and 1min after abrupt cessation of exercise (HRR-1). Regression analyses were adjusted for gender, age, LVEF, and maximum exercise capacity. RESULTS: Vital exhaustion explained 8.4% of the variance in continuous HRR-1 (p=0.045). For each point increase on the vital exhaustion score (range 0-18) there was a mean+/-SEM decrease of 0.54+/-0.26bpm in HRR-1. Type D personality showed a trend toward statistical significance for being associated with lower levels of HRR-1 explaining 6.5% of the variance (p<0.08). The likelihood of having HRR-1

The efficacy of psychological interventions for infertile patients: a meta-analysis examining mental health and pregnancy rate

BACKGROUND: Psychological interventions for infertile patients seek to improve mental health and increase pregnancy rates. The aim of the present meta-analysis was to examine if psychological interventions improve mental health and pregnancy rate among infertile patients. Thus, controlled studies were pooled investigating psychological interventions following the introduction of assisted reproductive treatments (ART). METHODS: The databases of Medline, PsycINFO, PSYNDEX, Web of Science and the Cochrane Library were searched to identify relevant articles published between 1978 and 2007 (384 articles). Included were prospective intervention studies on infertile patients (women and men) receiving psychological interventions independent of actual medical treatment. The outcome measures were mental health and pregnancy rate. A total of 21 controlled studies were ultimately included in a meta-analysis comparing the efficacy of psychological interventions. Effect sizes (ES) were calculated for psychological measures and risk ratios (RR) for pregnancy rate. RESULTS: The findings from controlled studies indicated no significant effect for psychological interventions regarding mental health (depression: ES 0.02, 99% CI: -0.19, 0.24; anxiety: ES 0.16, 99% CI: -0.10, 0.42; mental distress: ES 0.08, 99% CI: -0.10, 0.51). Nevertheless, there was evidence for the positive impact of psychological interventions on pregnancy rates (RR 1.42, 99% CI: 1.02, 1.96). Concerning pregnancy rates, significant effects for psychological interventions were only found for couples not receiving ART. CONCLUSIONS: Despite the absence of clinical effects on mental health measures, psychological interventions were found to improve some patients' chances of becoming pregnant. Psychological interventions represent an attractive treatment option, in particular, for infertile patients who are not receiving medical treatment.

Variable impact on mortality of AIDS-defining events diagnosed during combination antiretroviral therapy: not all AIDS-defining conditions are created equal

BACKGROUND: The extent to which mortality differs following individual acquired immunodeficiency syndrome (AIDS)-defining events (ADEs) has not been assessed among patients initiating combination antiretroviral therapy. METHODS: We analyzed data from 31,620 patients with no prior ADEs who started combination antiretroviral therapy. Cox proportional hazards models were used to estimate mortality hazard ratios for each ADE that occurred in >50 patients, after stratification by cohort and adjustment for sex, HIV transmission group, number of antiretroviral drugs initiated, regimen, age, date of starting combination antiretroviral therapy, and CD4+ cell count and HIV RNA load at initiation of combination antiretroviral therapy. ADEs that occurred in <50 patients were grouped together to form a "rare ADEs" category. RESULTS: During a median follow-up period of 43 months (interquartile range, 19-70 months), 2880 ADEs were diagnosed in 2262 patients; 1146 patients died. The most common ADEs were esophageal candidiasis (in 360 patients), Pneumocystis jiroveci pneumonia (320 patients), and Kaposi sarcoma (308 patients). The greatest mortality hazard ratio was associated with non-Hodgkin's lymphoma (hazard ratio, 17.59; 95% confidence interval, 13.84-22.35) and progressive multifocal leukoencephalopathy (hazard ratio, 10.0; 95% confidence interval, 6.70-14.92). Three groups of ADEs were identified on the basis of the ranked hazard ratios with bootstrapped confidence intervals: severe (non-Hodgkin's lymphoma and progressive multifocal leukoencephalopathy [hazard ratio, 7.26; 95% confidence interval, 5.55-9.48]), moderate (cryptococcosis, cerebral toxoplasmosis, AIDS dementia complex, disseminated Mycobacterium avium complex, and rare ADEs [hazard ratio, 2.35; 95% confidence interval, 1.76-3.13]), and mild (all other ADEs [hazard ratio, 1.47; 95% confidence interval, 1.08-2.00]). CONCLUSIONS: In the combination antiretroviral therapy era, mortality rates subsequent to an ADE depend on the specific diagnosis. The proposed classification of ADEs may be useful in clinical end point trials, prognostic studies, and patient management.

Heart rate response determines long term exercise capacity after heart transplantation

BACKGROUND: Exercise capacity after heart transplantation (HTx) remains limited despite normal left ventricular systolic function of the allograft. Various clinical and haemodynamic parameters are predictive of exercise capacity following HTx. However, the predictive significance of chronotropic competence has not been demonstrated unequivocally despite its immediate relevance for cardiac output. AIMS: This study assesses the predictive value of various clinical and haemodynamic parameters for exercise capacity in HTx recipients with complete chronotropic competence evolving within the first 6 postoperative months. METHODS: 51 patients were enrolled in this exercise study. Patients were included when at least >6 months after HTx and without negative chronotropic medication or factors limiting exercise capacity such as significant transplant vasculopathy or allograft rejection. Clinical parameters were obtained by chart review, haemodynamic parameters from current cardiac catheterisation, and exercise capacity was assessed by treadmill stress testing. A stepwise multiple regression model analysed the proportion of the variance explained by the predictive parameters. RESULTS: The mean age of these 51 HTx recipients was 55.4 +/- 13.2 yrs on inclusion, 42 pts were male and the mean time interval after cardiac transplantation was 5.1 +/- 2.8 yrs. Five independent predictors explained 47.5% of the variance observed for peak exercise capacity (adjusted R2 = 0.475). In detail, heart rate response explained 31.6%, male gender 5.2%, age 4.1%, pulmonary vascular resistance 3.7%, and body-mass index 2.9%. CONCLUSION: Heart rate response is one of the most important predictors of exercise capacity in HTx recipients with complete chronotropic competence and without relevant transplant vasculopathy or acute allograft rejection.

Surgical glove perforation and the risk of surgical site infection

HYPOTHESIS: Clinically apparent surgical glove perforation increases the risk of surgical site infection (SSI). DESIGN: Prospective observational cohort study. SETTING: University Hospital Basel, with an average of 28,000 surgical interventions per year. PARTICIPANTS: Consecutive series of 4147 surgical procedures performed in the Visceral Surgery, Vascular Surgery, and Traumatology divisions of the Department of General Surgery. MAIN OUTCOME MEASURES: The outcome of interest was SSI occurrence as assessed pursuant to the Centers of Disease Control and Prevention standards. The primary predictor variable was compromised asepsis due to glove perforation. RESULTS: The overall SSI rate was 4.5% (188 of 4147 procedures). Univariate logistic regression analysis showed a higher likelihood of SSI in procedures in which gloves were perforated compared with interventions with maintained asepsis (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.4-2.8; P < .001). However, multivariate logistic regression analyses showed that the increase in SSI risk with perforated gloves was different for procedures with vs those without surgical antimicrobial prophylaxis (test for effect modification, P = .005). Without antimicrobial prophylaxis, glove perforation entailed significantly higher odds of SSI compared with the reference group with no breach of asepsis (adjusted OR, 4.2; 95% CI, 1.7-10.8; P = .003). On the contrary, when surgical antimicrobial prophylaxis was applied, the likelihood of SSI was not significantly higher for operations in which gloves were punctured (adjusted OR, 1.3; 95% CI, 0.9-1.9; P = .26). CONCLUSION: Without surgical antimicrobial prophylaxis, glove perforation increases the risk of SSI.

The association of preoperative anemia and perioperative allogeneic blood transfusion with the risk of surgical site infection

BACKGROUND: The purpose of the study was to investigate allogeneic blood transfusion (ABT) and preoperative anemia as risk factors for surgical site infection (SSI). STUDY DESIGN AND METHODS: A prospective, observational cohort of 5873 consecutive general surgical procedures at Basel University Hospital was analyzed to determine the relationship between perioperative ABT and preoperative anemia and the incidence of SSI. ABT was defined as transfusion of leukoreduced red blood cells during surgery and anemia as hemoglobin concentration of less than 120 g/L before surgery. Surgical wounds and resulting infections were assessed to Centers for Disease Control standards. RESULTS: The overall SSI rate was 4.8% (284 of 5873). In univariable logistic regression analyses, perioperative ABT (crude odds ratio [OR], 2.93; 95% confidence interval [CI], 2.1 to 4.0; p < 0.001) and preoperative anemia (crude OR, 1.32; 95% CI, 1.0 to 1.7; p = 0.037) were significantly associated with an increased odds of SSI. After adjusting for 13 characteristics of the patient and the procedure in multivariable analyses, associations were substantially reduced for ABT (OR, 1.25; 95% CI, 0.8 to 1.9; p = 0.310; OR, 1.07; 95% CI, 0.6 to 2.0; p = 0.817 for 1-2 blood units and >or=3 blood units, respectively) and anemia (OR, 0.91; 95% CI, 0.7 to 1.2; p = 0.530). Duration of surgery was the main confounding variable. CONCLUSION: Our findings point to important confounding factors and strengthen existing doubts on leukoreduced ABT during general surgery and preoperative anemia as risk factors for SSIs.

Randomized controlled trial comparing a variable-thread novel tapered and a standard tapered implant: interim one-year results

STATEMENT OF PROBLEM: A tapered implant with continuously changing threads purported to provide stable tissue support and allow immediate function has been developed. Treatment success and stabilization of supporting tissues over time require documentation. PURPOSE: The purpose of this prospective, randomized, controlled, multicenter study was to evaluate changes in bone level and soft tissue behavior between the novel implant (NobelActive/NA) and a standard tapered implant (NobelReplace Tapered Groovy/NR) with regard to immediate function. MATERIAL AND METHODS: A total of 177 patients randomly allocated to 3 treatment groups (2 different test implant groups: NA Internal (n=117; internal connection) and External (n=82), and 1 standard treatment group, NR (n=126)) received 325 implants. Implants were placed into healed sites, and all but 6 implants were immediately nonocclusally loaded. Clinical and radiographic evaluations of treatment success, crestal bone levels, and soft tissue changes were performed at the time of placement and after 3, 6, and 12 months. Log-Rank test was used to analyze the differences in survival rate. Marginal bone level was compared using the Kruskal-Wallis test and Mann-Whitney U-test (alpha=.05). RESULTS: One-year cumulative survival rates were comparable (96.6% for NA Internal; 96.3% for NA External; 97.6% for NR; P=.852; Log-Rank). Mean (SD) change in bone level was -0.95 mm (1.37) for NA Internal, -0.64 mm (0.97) for NA External, and -0.63 mm (1.18) for NR (P=.589; Kruskal-Wallis). Stable soft tissues and significantly increased papilla scores (P<.001; Wilcoxon signed-rank) were observed for all implant types. CONCLUSIONS: The novel implants showed high survival rates as well as stable bone and soft tissue levels after 1 year, and may be recommended for clinical use, even under immediate function.

Intravaginal and intracervical application of seminal plasma in in vitro fertilization or intracytoplasmic sperm injection treatment cycles--a double-blind, placebo-controlled, randomized pilot study

OBJECTIVE: To evaluate whether intravaginal application of seminal plasma at the time of follicle aspiration in IVF or intracytoplasmic sperm injection treatment cycles has the potential to increase pregnancy rate. To calculate the number of patients needed to achieve significance in a multicenter trial. DESIGN: Double-blind, placebo-controlled randomized pilot study. SETTING: University department of gynecological endocrinology and reproductive medicine. PATIENT(S): One hundred sixty-eight patients undergoing IVF or intracytoplasmic sperm injection treatment. INTERVENTION(S): Cryopreserved seminal plasma from the patient's partner or sodium chloride (placebo) was injected into the cervix and the posterior fornix of the vagina just after follicle aspiration. MAIN OUTCOME MEASURE(S): Clinical-pregnancy rate. RESULT(S): One hundred sixty-eight patients agreed to participate in the study. Participation was limited to one treatment cycle. Thirty-one patients (18%) were excluded from the study, mainly as a result of canceled embryo transfers. Seventy patients received placebo, and 67 received seminal plasma. The clinical-pregnancy rate was 25.7% (18/70) in the placebo group. The clinical-pregnancy rate in the seminal plasma group reached 37.3% (25/67), corresponding to a relative increase of 45%. CONCLUSION(S): Even though significance was not reached in this pilot study, the data suggest that seminal plasma has the potential to improve pregnancy rate. It is estimated that around 450 patients need to be recruited to reach significance in a multicenter study.