Thermodynamics, Kinetics, and Activation energy Studies of the sorption of chromium(III) and chromium(VI) to a Mn 3 O 4 nanomaterial

In this study, a manganese oxide, Mn3O4 was used to remove chromium(III) and chromium(VI) from aqueous solutions. The Mn3O4 nanomaterial was synthesized through a precipitation method, and was characterized using XRD, which confirmed the material had a crystal structure similar to hausmannite. In addition, using Scherrer\u27s equation it was determined that the nanomaterial had an average grain size of 19.5 ± 1.10 nm. A study of the effects of pH on the binding of chromium(III) and chromium(VI) showed that the optimum binding pH was 4 and 3 respectively. Batch isotherm studies were performed to determine the binding capacity of chromium(III), which was determined to be 18.7 mg/g, 41.7 mg/g, and 54.4 mg/g respectively for 4°C, 21°C, and 45°C. Chromium(VI) on the other hand had lower binding capacities of 2.5 mg/g, 4.3 mg/g, and 5.8 mg/g for 4°C, 21°C, 45°C, respectively. Thermodynamic studies performed indicated the sorption process was for the most part controlled by physisorption. The ΔG for the sorption of chromium(III) and Chromium(VI) ranged from -0.9 to -13 kJ/mol, indicating a spontaneous reaction was occurring. The enthalpy indicated a endothermic reaction was occurring during the binding and show ΔH values of 70.6 and 19.1 kJ.mol for chromium(III) and Chromium(VI), respectively. In addition, ΔS for the reaction had positive values of 267 and 73 J/mol for chromium(III) and chromium(VI) which indicate a spontaneous reaction. In addition, the sorption process was found to follow pseudo second order kinetic and the activation energy studies indicated the binding process occurred through chemisorption

Surgical Instrument Restraint in Weightlessness

Performing a surgical procedure during spaceflight will become more likely with longer duration missions in the near future. Minimal surgical capability has been present on previous missions as the definitive medical care time was short and the likelihood of surgical events too low to justify surgical hardware availability. Early demonstrations of surgical procedures in the weightlessness of parabolic flight indicated the need for careful logistical planning and restraint of surgical hardware. The consideration of human ergonomics also has more impact in weightlessness than in the conventionall-g environment. Three methods of surgical instrument restraint - a Minor Surgical Kit (MSK), a Surgical Restraint Scrub Suit (SRSS), and a Surgical Tray (ST) were evaluated in parabolic flight surgical procedures. The Minor Surgical Kit was easily stored, easily deployed, and demonstrated the best ability to facilitate a surgical procedure in weightlessness. Important factors in this surgical restraint system include excellent organization of supplies, ability to maintain sterility, accessibility while providing secure restraint, ability to dispose of sharp items and biological trash, and ergonomical efficiency

Patient perception of physician compassion after a more optimistic vs a less optimistic message: A randomized clinical trial

IMPORTANCE: Information regarding treatment options and prognosis is essential for patient decision making. Patient perception of physicians as being less compassionate when they deliver bad news might be a contributor to physicians' reluctance in delivering these types of communication. OBJECTIVE: To compare patients' perception of physician compassion after watching video vignettes of 2 physicians conveying a more optimistic vs a less optimistic message, determine patients' physician preference after watching both videos, and establish demographic and clinical predictors of compassion. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial at an outpatient supportive care center in a cancer center in Houston, Texas, including English-speaking adult patients with advanced cancer who were able to understand the nature of the study and complete the consent process. Actors and patients were blinded to the purpose of the study. Investigators were blinded to the videos observed by the patient. INTERVENTION: One hundred patients were randomized to observe 2 standardized, roughly 4-minute videos depicting a physician discussing treatment information (more optimistic message vs less optimistic message) with a patient with advanced cancer. Both physicians made an identical number of empathetic statements (5) and displayed identical posture. After viewing each video, patients completed assessments including the Physician Compassion Questionnaire (0 = best, 50 = worst). MAIN OUTCOMES AND MEASURES: Patients' perception of physician compassion after being exposed to a more optimistic vs an equally empathetic but less optimistic message. RESULTS: Patients reported significantly better compassion scores after watching the more optimistic video as compared with the less optimistic video (median [interquartile range], 15 [5-23] vs 23 [10-31]; P < .001). There was a sequence effect favoring the second video on both compassion scores (P < .001) and physician preference (P < .001). Higher perception of compassion was found to be associated with greater trust in the medical profession independent of message type: 63 patients observing the more optimistic message ranked the physician as trustworthy vs 39 after the less optimistic message (P = .03). CONCLUSIONS AND RELEVANCE: Patients perceived a higher level of compassion and preferred physicians who provided a more optimistic message. More research is needed in structuring less optimistic message content to support health care professionals in delivering less optimistic news. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02357108