Role of tannin pretreatment in flotation separation of magnesite and dolomite

Flotation separation of magnesite and its calcium-containing carbonate minerals is a difficult problem.Recently,new regulat-ors have been proposed for magnesite flotation decalcification,although traditional regulators such as tannin,water glass,sodium carbon-ate,and sodium hexametaphosphate are more widely used in industry.However,they are rarely used as the main regulators in research because they perform poorly in magnesite and dolomite single-mineral flotation tests.Inspired by the limonite presedimentation method and the addition of a regulator to magnesite slurry mixing,we used a tannin pretreatment method for separating magnesite and dolomite.Microflotation experiments confirmed that the tannin pretreatment method selectively and largely reduces the flotation recovery rate of dolomite without affecting the flotation recovery rate of magnesite.Moreover,the contact angles of the tannin-pretreated magnesite and dolomite increased and decreased,respectively,in the presence of NaOl.Zeta potential and Fourier transform infrared analyses showed that the tannin pretreatment method efficiently hinders NaOl adsorption on the dolomite surface but does not affect NaOl adsorption on the magnesite surface.X-ray photoelectron spectroscopy and density functional theory calculations confirmed that tannin interacts more strongly with dolomite than with magnesite.

Selective serotonin re-uptake inhibitor sertraline inhibits bone healing in a calvarial defect model

Bone wound healing is a highly dynamic and precisely controlled process through which damaged bone undergoes repair and complete regeneration. External factors can alter this process, leading to delayed or failed bone wound healing. The findings of recent studies suggest that the use of selective serotonin reuptake inhibitors(SSRIs) can reduce bone mass, precipitate osteoporotic fractures and increase the rate of dental implant failure. With 10% of Americans prescribed antidepressants, the potential of SSRIs to impair bone healing may adversely affect millions of patients’ ability to heal after sustaining trauma. Here, we investigate the effect of the SSRI sertraline on bone healing through pre-treatment with(10 mg·kg-1sertraline in drinking water, n = 26) or without(control, n = 30) SSRI followed by the creation of a 5-mm calvarial defect. Animals were randomized into three surgical groups:(a) empty/sham,(b) implanted with a DermaMatrix scaffold soak-loaded with sterile PBS or(c) DermaMatrix soak-loaded with542.5 ng BMP2. SSRI exposure continued until sacrifice in the exposed groups at 4 weeks after surgery. Sertraline exposure resulted in decreased bone healing with significant decreases in trabecular thickness, trabecular number and osteoclast dysfunction while significantly increasing mature collagen fiber formation. These findings indicate that sertraline exposure can impair bone wound healing through disruption of bone repair and regeneration while promoting or defaulting to scar formation within the defect site.

Achieving and maintaining biological nitrogen removal via nitrite under normal conditions

The principal aim of this paper is to develop an approach to realize stable biological nitrogen removal via nitrite under normal conditions. Validation of the new method was established on laboratory-scale experiments applying the sequencing batch reactor（SBR） activated sludge process to domestic wastewater with low C/N ratio. The addition of sodium chloride（NaCI） to influent was established to achieve nitrite build-up. The high nitrite accumulation, depending on the salinity in influent and the application duration of salt, was obtained in SBRs treating saline wastewater. The maintenance results indicated that the real-time SBRs can maintain stable nitrite accumulation, but conversion from shorter nitrification-denitrification to full nitrification-denitrification was observed after some operation cycles in the other SBR with fixed-time control. The presented method is valuable to offer a solution to realize and to maintain nitrogen removal via nitrite under normal conditions.

Osteoclast-derived microRNA-containing exosomes selectively inhibit osteoblast activity

With the support by the National Natural Science Foundation of China and National Basic Research Program of China,the research team led by Prof.Li Yingxian(李英贤)at the State Key Laboratory of Space Medicine Fundamentals and Application,China Astronaut Research and Training Center,discovered that osteoclast-derived microRNA-containing exosomes selectively inhibited osteoblast activity,which was pub-

Selective serotonin reuptake inhibitors in the treatment of premature ejaculation

Objective To review and assess the update studies regarding selective serotonin reuptake inhibitors （SSRIs） in the treatment of premature ejaculation （PE） and then provide practical recommendations and possible mechanisms concerning state of the art knowledge for the use of SSRIs in alleviating PE. Data sources Using the Medline, 48 articles published from January 1st, 1996 to August 1st, 2006 concerning the use of SSRIs and their possible mechanisms in alleviating PE were found and reviewed. Study selection PE, rapid ejaculation, early ejaculation and SSRIs were employed as the keywords, and relevant articles about the use of SSRIs and their possible mechanisms in the treatment of PE were selected. Results Many kinds of SSRIs, such as fluoxetine, sertraline, paroxetine and citalopram, have widely been employed to treat PE. However, their effects are moderate and there is no a universal agreement about the kind, dose, protocol and duration. Dapoxetine, as the first prescription treatment of PE, may change this bottle-neck situation. SSRIs are suggested to be used in young men with lifelong PE, and acquired PE when etiological factors are removed but PE still exists. Phosphodiesterase 5 inhibitors （PDE5-ls） are suggested to be employed alone or combined with SSRIs when SSRIs fail to treat PE or sexual dysfunction associated with SSRIs occurs. The protocol of taking drugs on demand based on taking them daily for a suitable period is proposed to be chosen firstly. The possible mechanisms include increasing serotonergic neurotransmission and activating 5-hydroxytryptamine 2C （5-HT2c） receptors, then switching the ejaculatory threshold to a higher level, decreasing the penile sensitivity and their own effect of antidepression. Conclusion The efficacies of the current SSRIs are moderate in the treatment of PE and they have not been approved by the FDA, therefore new SSRI like dapoxetine needs to be further evaluated.

Natural small-molecule sappanone A selectively targets IMPDH2 to inhibit neuroinflammation

With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Tu Pengfei(屠鹏飞)from the School of Pharmaceutical Sciences,Peking University demonstrates that natural small-molecule sappanone A directly targets IMPDH2to block its activity,

Design, Synthesis and Biological Evaluation of 2-（2-Aryl- morpholino-4-yl）ethyl Esters of Indomethacin as Potential Cyclooxygenase-2 （COX-2） Inhibitors

A number of novel 2-（2-arylmorpholino-4-yl）ethyl 1-（4-chlorobenzoyl）-5-methoxy-2-methyl-lH-indol-3- acetate hydrochlorides were synthesized and tested for their cyclooxygenase （COX-1 and COX-2） inhibition prop- erties in vitro. Many of these compounds exhibited moderate to good selective COX-2 inhibition, and subtle struc- tural changes in the substituents on the side chain of the ester moiety altered the inhibitory properties significantly. 2-[2-（4-Butoxyphenyl）morpholino-4-yl]ethyl 1-（4-chlorobenzoyl）-5-methoxy-2-methyl-IH-indol-3-acetate hydro- chloride （If）, showed good selective COX-2 inhibitory activity （Selective index （SI） 182）, which is comparative with celecoxib （SI 214）, a COX-2 inhibitor of diarylpyrazoles. While 2-[2-（2,4-dichloro-5-fluorophenyl）mor- pholino-4-yl]ethyl 1-（4-chlorobenzoyl）-5-methoxy-2-methyl-IH-indol-3-acetate hydrochloride （lg）, showed greater selective COX-2 inhibitory activity （SI 358） than celecoxib. Both compounds were identified as compromising de- rivatives in this class to reduce the side effects generated by nonsteroidal anti-inflammatory drugs （NSAIDs） indo- methacin.