Here, pyridinic nitrogen dominated graphene aerogels with/without iron incorporation (Fe‐NG and NG) are prepared via a facile and effective process including freeze‐drying of chemically reduced graphene oxide with/without iron precursor and thermal treatment in NH3. A high doping level of nitrogen has been achieved (up to 12.2 at% for NG and 11.3 at% for Fe‐NG) with striking enrichment of pyridinic nitrogen (up to 90.4% of the total nitrogen content for NG, and 82.4% for Fe‐NG). It is found that the Fe‐NG catalysts display a more positive onset potential, higher current density, and better four‐electron selectivity for ORR than their counterpart without iron incorporation. The most active Fe‐NG exhibits outstanding ORR catalytic activity, high durability, and methanol tolerance ability that are comparable to or even superior to those of the commercial Pt/C catalyst at the same catalyst loading in alkaline environment. The excellent ORR performance can be ascribed to the synergistic effect of pyridinic N and Fe‐N x sites (where iron probably coordinates with pyridinic N) that serve as active centers for ORR. Our Fe‐NG can be developed into cost‐effective and durable catalysts as viable replacements of the expensive Pt‐based catalysts in practical fuel cell applications.
A hierarchical N-doped carbon nanotube-graphene hybrid nanostructure (NCNT-GHN), in which the graphene layers distributed inside the CNT inner cavities, is designed to support noble metal (e.g. PtRu) nanoparticles efficiently. Well-dispersed PtRu nanoparticles with diameters of 2-4 nm are immobilized onto NCNT-GHN supports by a low-temperature chemical reduction method without requiring any pretreatment. Compared with conventional CNTs and commercial catalyst, much enhanced catalytic performance is achieved by a synergistic effect of the hierarchical structure (graphene-CNT hybrid) and electronic modulation (N-doping) during the methanol electrooxidation reaction. An improved singlecell performance with long-term stability is also demonstrated by using NCNT-GHN as catalyst support. These results explain previously reported findings on highly dispersed gold nanoparticles, in which the peripheral atoms are positively charged
Ferromagnetism and the Kondo effect are crucial for 3d electrons to become spin-separated and heavy at the same time.
PURPOSE This study was designed to evaluate potential preventive effects of meditation or exercise on incidence, duration, and severity of acute respiratory infection (ARI) illness.METHODS Community-recruited adults aged 50 years and older were randomized to 1 of 3 study groups: 8-week training in mindfulness meditation, matched 8-week training in moderate-intensity sustained exercise, or observational control. The primary outcome was area-under-the-curve global illness severity during a single cold and infl uenza season, using the Wisconsin Upper Respiratory Symptom Survey (WURSS-24) to assess severity. Health care visits and days of missed work were counted. Nasal wash collected during ARI illness was assayed for neutrophils, interleukin-8, and viral nucleic acid. RESULTSOf 154 adults randomized into the study, 149 completed the trial (82% female, 94% white, mean age 59.3 ± 6.6 years). There were 27 ARI episodes and 257 days of ARI illness in the meditation group (n = 51), 26 episodes and 241 illness days in the exercise group (n = 47), and 40 episodes and 453 days in the control group (n = 51). Mean global severity was 144 for meditation, 248 for exercise, and 358 for control. Compared with control, global severity was signifi cantly lower for meditation (P = .004). Both global severity and total days of illness (duration) trended toward being lower for the exercise group (P = .16 and P = .032, respectively), as did illness duration for the meditation group (P = .034). Adjusting for covariates using zero-infl ated multivariate regression models gave similar results. There were 67 ARI-related days of-work missed in the control group, 32 in the exercise group (P = .041), and 16 in the meditation group (P <.001). Health care visits did not differ signifi cantly. Viruses were identifi ed in 54% of samples from meditation, 42% from exercise, and 54% from control groups. Neutrophil count and interleukin-8 levels were similar among intervention groups. CONCLUSIONSTraining in meditation or exercise may be effective in reducing ARI illness burden.
Objective To evaluate the effects of patient-practitioner interaction on the severity and duration of the common cold. Methods We conducted a randomized controlled trial of 719 patients with new cold onset. Participants were randomized to three groups: no patient-practitioner interaction, “standard” interaction or an “enhanced” interaction. Cold severity was assessed twice daily. Patients randomized to practitioner visits used the Consultation and Relational Empathy (CARE) measure to rate clinician empathy. Interleukin 8 (IL-8) and neutrophil counts were obtained from nasal wash at baseline and 48 hours later. Results Patients’ perceptions of the clinical encounter were associated with reduced cold severity and duration. Encounters rated perfect on the CARE score had reduced severity (Perfect: 223, sub-perfect: 271, p=0.04) and duration (Perfect: 5.89 days, sub-perfect: 7.00 days, p=0.003). CARE scores were also associated with a more significant change in IL-8 (Perfect: mean IL-8 change 1586, sub-perfect: 72, p=0.02) and neutrophil count (Perfect: 49, sub-perfect: 12, p=0.09). Conclusions When patients perceive clinicians as empathetic, rating them perfect on the CARE tool, the severity, duration and objective measures (IL-8 and neutrophils) of the common cold significantly change. Practice Implications This study helps us understand the importance of the perception of empathy in a therapeutic encounter.
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