Influence of carbonization temperature on cobalt-based nitrogendoped carbon nanopolyhedra derived from ZIF-67 for nonoxidative propane dehydrogenation

Propylene is a significant basic material for petrochemicals such as polypropylene,propylene oxide,etc.With abundant propane supply from shale gas,propane dehydrogenation(PDH)becomes extensively attractive as an on-purpose propylene production route in recent years.Nitrogen-doped carbon(NC)nanopolyhedra supported cobalt catalysts were synthesized in one-step of ZIF-67 pyrolysis and investigated further in PDH.XPS,TEM and N_(2) adsorption-desorption were used to study the influence of carbonization temperature on as-prepared NC supported cobalt catalysts.The temperature is found to affect the cobalt phase and nitrogen species of the catalysts.And the positive correlation was established between Co0 proportion and space time yield of propylene,indicating that the modulation of carbonization temperature could be important for catalytic performance.

Novel CoAl-LDH Nanosheets/BiPO_(4) nanorods composites for boosting photocatalytic degradation of phenol

Layered double hydroxide(LDH)with special layered structure has been proved to have excellent hole transport capacity and good stability.Herein,we report a high efficient composite photocatalyst of CoAlLDH and BiPO4prepared by hydrothermal and che mical adsorption(denoted as CoAl-LDH/BiPO_(4)).Phenol can be entirely degraded by 1%CoAl-LDH/BiPO_(4)under 30 min ultraviolet(UV)light irradiation,and the degradation rate constants k are 3 times and 39 times higher than that of pure BiPO_(4)and CoAl-LDH,respectively.The enhanced photocatalytic activity can be attributed to effective holes transfer from BiPO4to CoAl-LDH,which hinders the recombination of photo genera ted charge carriers.In addition,the combination of BiPO4and CoAl-LDH avoids the agglomeration of BiPO4and improves the stability of BiPO_(4).Active species capture experiments indicate that superoxide radicals(·O-_(2))are the main active species responsible for the degradation of phenol.This work provides technical approaches and research ideas for solving the photogenerated charge carrier recombination problem of photocatalyst.

The Hug-up Test： A New, Sensitive Diagnostic Test for Supraspinatus Tears

Background： The supraspinatus tendon is the most commonly affected tendon in rotator cuff tears. Early detection ofa supraspinatus tear using an accurate physical examination is, therefore, important. However, the currently used physical tests for detecting supraspinatus tears are poor diagnostic indicators and involve a wide range of sensitivity and specificity values. Therefore, the aim of this study was to establish a new physical test for the diagnosis of supraspinatus tears and evaluate its accuracy in comparison with conventional tests. Methods： Between November 2012 and January 2014, 200 consecutive patients undergoing shoulder arthroscopy were prospectively evaluated preoperatively. The hug-up test, empty can （EC） test, full can （FC） test, Neer impingement sign, and Hawkins-Kennedy impingement sign were used and compared statistically tbr their accuracy in terms of supraspinatus tears, with arthroscopic findings as the gold standard. Muscle strength was precisely quantified using an electronic digital tensiometer. Results： The prevalence of supraspinatus tears was 76.5%. The hug-up test demonstrated the highest sensitivity （94.1%）, with a low negative likelihood ratio （NLR, 0.08） and comparable specificity （76.6%） compared with the other four tests. The area under the receiver operating characteristic curve for the hug-up test was 0.854, with no statistical difference compared with the EC test （z = 1.438, P = 0.075） or the FC test （z = 1.498, P = 0.067）. The hug-up test showed no statistical difference in terms of detecting different tear patterns according to the position （X2 = 0.578, P = 0.898） and size （Fisher＇s exact test, P 〉 0.999） compared with the arthroscopic examination. The interobserver reproducibility of the hug-up test was high, with a kappa coefficient of 0.823. Conclusions： The hug-up test can accurately detect supraspinatus tears with a high sensitivity, comparable specificity, and low NLR compared with the conventional clinical tests and could, therefore, improve the diagnosis of supraspinatus tears in clinical settings.