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Objective: To determine if initial American Board of Surgery certification in general surgery is associated with better risk-adjusted patient outcomes for Medicare patients undergoing partial colectomy by an early career surgeon. Background: Board certification is a voluntary commitment to professionalism, continued learning, and delivery of high-quality patient care. Not all surgeons are certified, and some have questioned the value of certification due to limited evidence that board-certified surgeons have better patient outcomes. In response, we examined the outcomes of certified versus noncertified early career general surgeons. Methods: We identified Medicare patients who underwent a partial colectomy between 2008 and 2016 and were operated on by a non-subspecialty trained surgeon within their first 5 years of practice. Surgeon certification status was determined using the American Board of Surgery data. Generalized linear mixed models were used to control for patient-, procedure-, and hospital-level effects. Primary outcomes were the occurrence of severe complications and occurrence of death within 30 days. Results: We identified 69,325 patients who underwent a partial colectomy by an early career general surgeon. The adjusted rate of severe complications after partial colectomy by certified (n = 4239) versus noncertified (n = 191) early-career general surgeons was 9.1% versus 10.7% (odds ratio 0.83, P = 0.03). Adjusted mortality rate for certified versus noncertified early-career general surgeons was 4.9% versus 6.1% (odds ratio 0.79, P = 0.01). Conclusion: Patients undergoing partial colectomy by an early career general surgeon have decreased odds of severe complications and death when their surgeon is board certified. [ABSTRACT FROM AUTHOR]

Abstract Solar fraction is an important index to evaluate the energy saving effect of solar hot water system. However, the practical operation indicates that it has some limitations and fails to achieved anticipate result of energy saving if use it only. Therefore, the centralized solar hot water system of residential area in Tianjin is studied, the mathematical model of the heat-collecting unit, heat-supply unit and heat-using unit were established, and the mathematical model of the whole system is formed. MATLAB language was used to write the calculation procedures based on the above model, providing support for the research of system optimization and performance. And the performance index of the system is applied to simulated calculation. Based on the results of the simulation, the system performance in the whole-year, the effect of water consumption and the control strategies on the operation performance of this system are studied. Four parameters, solar fraction, solar energy utilization, efficient replacement ratio of foil energy, system heat dissipation ratio has been proposed as system performance evaluating index, and the strategy of reducing the water cycling time properly is put forward. [ABSTRACT FROM AUTHOR]

Abstract Two typical residential solar hot water engineering cases located in Chifeng and Tianjin are tested respectively. From the point of energy balance, a total of four parts of energy are calculated for the heat gain of heat collecting system, auxiliary energy consumption, and system heat loss, heat consumption of end users. It finds that solar fraction as an important reference index of the system design has certain limitations when evaluating the actual running system. In order to conduct a more comprehensive assessment of the actual energy-saving efficiency of solar hot water systems, three new kinds of evaluation index are put forward, which are solar energy utilization ratio, efficient replacement rate of fuel energy and system heat loss ratio. [ABSTRACT FROM AUTHOR]

Many studies have found that the decrease of photovoltaic (PV) cell temperature would increase the solar-to-electricity conversion efficiency. This paper provided a study on the thermal and electrical performance of PV panel with active cooling by attaching heat pipes beneath the PV panel, building up a PV-heat pipe (HP) combined system. The effect of solar radiation, inlet water temperature and water flow on the electrical and thermal efficiencies of the system were studied. The results showed that the thermal efficiency of the heat pipe PV/thermal (PV/T) solar water heating system decreased with the increasing inlet water temperature and water flow, and increased with the increasing solar radiation; the electrical efficiency decreased with increasing solar radiation, inlet water temperature and water flow. [ABSTRACT FROM AUTHOR]

Many studies have found that the decrease of photovoltaic (PV) cell temperature would increase the solar-to-electricity conversion efficiency. This paper provided a study on the thermal and electrical performance of PV panel with active cooling by attaching heat pipes beneath the PV panel, building up a PV-heat pipe (HP) combined system. The effect of solar radiation, inlet water temperature and water flow on the electrical and thermal efficiencies of the system were studied. The results showed that the thermal efficiency of the heat pipe PV/thermal (PV/T) solar water heating system decreased with the increasing inlet water temperature and water flow, and increased with the increasing solar radiation; the electrical efficiency decreased with increasing solar radiation, inlet water temperature and water flow. [ABSTRACT FROM AUTHOR]

Long-term cycling performances of LiFePO4/graphite batteries have been investigated in different state-of-charge (SOC) ranges. It is found that batteries cycled in the medium SOC range exhibit superior cycling stability over those cycled at both ends of the SOC ranges. A variety of characterization techniques, including galvanostatic intermittent titration technique (GITT) analysis, model-based parameter identification, electrochemical impedance spectroscopy analysis, and entropy change test, were used to investigate the performance difference of the batteries cycled in different SOC ranges. The results reveal that batteries at the end of SOC exhibit much higher polarization impedance than those within the medium-SOC range. This result can be attributed to the significant structural change of the cathode and anode materials as revealed by the large entropy change within these SOC regions. Identification of the best operating conditions for LiFePO4/graphite batteries will significantly extend their cycle life. The general control principle obtained in this work, such as modulating the charge/discharge current to minimize the impedance extremes can also be used in the operation control of other battery systems. [ABSTRACT FROM AUTHOR]

The application of lithium (Li) metal anodes in rechargeable batteries is hindered by Li dendrite growth during Li deposition and low Li Coulombic efficiency (CE), where the nonaqueous electrolyte plays a critical role. In this work, the effects of different carbonate solvents and Li salts on Li deposition morphology and CE were systematically investigated. Typically, cyclic carbonates favor the formation of uniform Li films and improve Li CE more than linear carbonates do. Several specific cyclic carbonates that are conventionally used as solid electrolyte interphase (SEI) formation additives in Li-ion batteries can also improve the CE of Li anodes. Furthermore, among the nine electrolyte salts studied, LiAsF6 and lithium bis(oxalato)borate (LiBOB) lead to the highest CE. LiBOB also leads to better uniformity of deposited Li than other salts do. Considering the better safety of LiBOB as compared to LiAsF6, LiBOB is a promising salt for rechargeable Li metal batteries with high CE. By combining the best electrolyte solvent/salt that can lead to high CE with novel electrolyte additives that can prevent dendrite formation, it is possible to find an electrolyte that not only prevents Li dendrite formation but also leads to high CE during Li deposition/stripping processes. [ABSTRACT FROM AUTHOR]

The ionic conductivity of Sn0.9In0.1P2O7 ceramic was investigated under various atmospheres within the temperature range of 130-230°C. Similar to mixed-conductive perovskite oxides at high temperatures (such as SrCe0.95Yb0.05O3-αLa0.9Sr0.1Ga0.8Mg0.2O3-α at 600-1000°C), Sn0.9In0.1P2O7 can conduct both protons and oxide ions at low temperatures (130-230°C). The conductivity of Sn0.9In0.1P2O7 reaches 0.019 S/cm at 200°C in wet nitrogen. Its transport numbers determined by steam concentration cells are around 0.76 for a proton and 0.12 for an oxide ion. The performance of direct methanol fuel cells at 170°C using mixed-ion conductive Sn0.9In0.1P2O7 electrolyte is higher than that at 235°C using pure proton conductive CsH2PO4 electrolyte. This is attributed to direct oxidation of CO at the anode by the oxide ions generated at the cathode and moved through the Sn0.9ln0.1P2O7 electrolyte. [ABSTRACT FROM AUTHOR]