Eight new polyphosphates containing both nucleic acid base and phosphonoacetic acid ethyl ester were synthesized by the polycondensation of P, P-dichloride of phosphonoacetic acid ethyl ester with 1, 3-dihydroxyalkyl-...Eight new polyphosphates containing both nucleic acid base and phosphonoacetic acid ethyl ester were synthesized by the polycondensation of P, P-dichloride of phosphonoacetic acid ethyl ester with 1, 3-dihydroxyalkyl-5-fluorouracil, 1,3-dihydroxyalkyl-uracil and 1,3-dihydroxyalkylthymine. These polyphosphates were tested against Ehrlich Ascites Carcinoma in mice. Polymer IIa and IIc exhibited excellent antitumor activity. IIc also showed lower toxicity.展开更多
A new class of crosslinking polyphosphates were synthesized characterizedby IR 1HNMR, 31PNMR spectroscopy as well as elemental analysis. In vitrodegradation of the polyphosphates obtained and the release of antineopla...A new class of crosslinking polyphosphates were synthesized characterizedby IR 1HNMR, 31PNMR spectroscopy as well as elemental analysis. In vitrodegradation of the polyphosphates obtained and the release of antineoplastic drugMethotrexate (MTX) and contraceptive Levonorgestrel (LNG ) by nsing thesepolymers as matrix were studied. Zero order release rate was rkserved in the case ofLNG release.展开更多
In neurosurgery procedures,cerebrospinal fluid leakage is a commonly encountered complication.Re-constructing skull base defects with patch materials can reduce the risk of cerebrospinal fluid leakage which can lead t...In neurosurgery procedures,cerebrospinal fluid leakage is a commonly encountered complication.Re-constructing skull base defects with patch materials can reduce the risk of cerebrospinal fluid leakage which can lead to serious issues such as infection,meningitis,arachnoiditis,and delayed wound healing.An ideal skull base reconstruction material should not only serve as a leak-proof barrier but also pro-mote skull base bone regeneration.To fulfill this challenge,this research designed and fabricated a Janus orthogonal bilayer nanofiber membrane(OPCL/PG-PCPP).The aligned PCL(APCL)nanofibers were con-stituted as the top layer to resist cerebrospinal fluid leakage,while the perpendicular PCL/gelatin(APG)fibers with calcium polyphosphate encapsulated polydopamine nanoparticles(CPP@PDA,labeled as PCPP)were designed as the bottom layer(APG-PCPP)to facilitate osteoblast migration and osteogenic differen-tiation.Among these,APG-1%PCPP nanofibers demonstrated the most effective induction of osteogenic differentiation in bone marrow mesenchymal stem cells(rBMSCs).Subsequent in vivo animal experi-ments revealed that the bone surface area(BS),bone volume fraction(BV/TV),and number of trabec-ulae(Tb.N)in the APG-1%PCPP group were twice as high as those in the control group,which confirmed the good osteogenic potentials.Therefore,due to its unique leak-proof and osteoinductive properties,the OPCL/PG-PCPP membrane holds promise as an applicable skull base reconstruction material in the field of neurosurgery.展开更多
Aging is considered the main risk factor for the development of several diseases,including the leading neurodegenerative disorders.While the cellular features of aging are complex and multifaceted,neuronal senescence ...Aging is considered the main risk factor for the development of several diseases,including the leading neurodegenerative disorders.While the cellular features of aging are complex and multifaceted,neuronal senescence has emerged as a major contributor and driver of this process in the mammalian cell.Cellular senescence is a programmed response to stress and irreparable damage,which drives the cell into an apoptosis-resistant,non-proliferative state.Senescent cells can also deleteriously affect neighboring,non-senescent cells.Senescence is a complex and multifaceted process associated with a wide range of cellular events,including the secretion of pro-inflammatory molecules and the arrest of the cell cycle.展开更多
Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries ...Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.展开更多
Acinetobacter baumannii(A.baumannii)is well known for its virulence and persistence,particularly in intensive care units.Therefore,new strategies and candidates to treat A.baumannii infection are urgently needed consi...Acinetobacter baumannii(A.baumannii)is well known for its virulence and persistence,particularly in intensive care units.Therefore,new strategies and candidates to treat A.baumannii infection are urgently needed considering the emergence of drug-resistant bacteria.Polyphosphate kinase 1(PPK1)is required for bacterial survival as it is involved in maintaining antibiotic resistance or tolerance,pathogenesis,and adversity resistance.Multiple phenotypic assays related to virulence and persistence were performed in this study,and phloretin was shown to attenuate A.baumannii virulence and persistence by inhibiting PPK1 activity.Phloretin hampered mobility,interfered with biofilm formation and decreased resistance to ampicillin,heat,and hydrogen peroxide stress in A.baumannii.The therapeutic effect was also examined in a mouse pneumonia infection model.Molecular simulation and site-directed mutagenesis revealed that ARG-22,MET-622,ASN-57,and ARG-65 were the sites of phloretin action against PPK1.Phloretin treatment led to changes in metabolic pathways associated with A.baumannii virulence and persistence,including glycerophospholipid metabolism and fatty acid biosynthesis.Furthermore,phloretin alleviated pneumonic injury in a mouse pneumonia infection model in vivo,indicating that phloretin is a promising compound for preventing A.baumannii infection resistance by targeting PPK1.展开更多
The thermal behaviors and burning characteristics of reconstituted tobacco （RT） are strongly related with evolved gaseous products. The effect of ammonium polyphosphate （APP） as an additive of RT on the pyrolysis ...The thermal behaviors and burning characteristics of reconstituted tobacco （RT） are strongly related with evolved gaseous products. The effect of ammonium polyphosphate （APP） as an additive of RT on the pyrolysis behavior and CO evolution was studied, emphasizing the role of heating velocity in reducing CO delivery of the mainstream smoke by APP. Thermogravimetric analysis （TGA） was employed to investigate the influence of APP on RT thermal behavior. Slow and flash pyrolysis of RT were compared to discuss the role of heating rate in decreasing CO by APP. TGA results demonstrated that, in dependence on APP concentration, APP influenced exothermal amount and weight loss rate during RT thermal decomposition, promoted the formation of char and retarded the thermal decomposition of RT. In addition, APP had a considerable influence on the evolution of gaseous products during thermal decomposition of RT. Both CO delivery per cigarette and that per puff in the smoking process were significantly reduced in dependence on APP content in RT. Comparative analysis of CO evolution patterns in the flash and slow pyrolysis elucidated that heating rate played a key role in decreasing CO evolution by APP. The results suggest that APP is a potential burning additive for controlling CO delivery in mainstream smoke of RT.展开更多
A series of novel polyphosphonates containing 5-flouro- N1-furanyl-N3- glyceroalkyl-uracil and formyl groups was synthesized by the condensation of 3-(w- (1-furanyl-5-flourouracil-3-yl) alkoxy)-1, 2-dihydroxy propane ...A series of novel polyphosphonates containing 5-flouro- N1-furanyl-N3- glyceroalkyl-uracil and formyl groups was synthesized by the condensation of 3-(w- (1-furanyl-5-flourouracil-3-yl) alkoxy)-1, 2-dihydroxy propane with phosphonyl dichloride. The products were characterized by IR, 1H NMR, 31P NMR, M, and elemental analysis. The results of bioassay show that compound 8a possesses potential anticancer activity.展开更多
The ubiquitin-activating enzyme E1 (EC 6.3.2.19) represents the first step in the degradation of proteins by the ubiquitin proteasome pathway. E1 transfers ubiquitin from the ubiquitinated E1 to the ubiquitin carrier ...The ubiquitin-activating enzyme E1 (EC 6.3.2.19) represents the first step in the degradation of proteins by the ubiquitin proteasome pathway. E1 transfers ubiquitin from the ubiquitinated E1 to the ubiquitin carrier proteins (E2), ubiquitin-protein ligases (E3) and proteins. This process is rather complex, and known from the work of Haas, Ciechanover, Hershko, Rose and others. The occurrence of 19 hypothetical intermediate enzyme forms (EFs) and 22 different reactions were considered in the presence of ubiquitin (Ub), ATP, adenosine 5’-tetraphosphate (p4A), pyrophosphate (P2), and tripolyphosphate (P3) as substrates, and iodoacetamide (IAA) and dithioth- reitol (DTT) as inhibitors. Inspired by the work of Cha (Cha (1968) J. Biol. Chem., 243, 820-825) we have treated these reactions in two complementary ways: in rapid equilibrium and in steady state. The kinetics of both types of reactions were simulated and solved with a system of ordinary differential equations using the Mathematica Program. The ubiquitination of E1 has been also theoretically coupled to the ubiquitination of E2, E3 and proteins. This makes the model useful to predict the theoretical influence of inhibitors (or of changes in some parameters of the reaction) on the ubiquitination of proteins. The Program responds to changes in the concentration of ATP or ubiquitin and has predictive properties as shown by the influence of AMP on the synthesis of p4A, calculated theoretically and confirmed experimentally.展开更多
Dipentaerythritol(DPER),4,40-diphenylmethanediisocyanate(MDI)and melamine(MEL)are used as raw materials to microencapsulate ammonium polyphosphate(MAPP)in situ polymerization.The MAPP is characterized by Fourier trans...Dipentaerythritol(DPER),4,40-diphenylmethanediisocyanate(MDI)and melamine(MEL)are used as raw materials to microencapsulate ammonium polyphosphate(MAPP)in situ polymerization.The MAPP is characterized by Fourier transform infrared(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and thermal gravimetric analysis(TGA).The results show that the coating operation can effectively improve water resistance of ammonium polyphosphate(APP),and MAPP has higher residual rate than that of APP after combustion.The flame retardant action of MAPP and APP in polypropylene(PP)is investigated by the limited oxygen index(LOI),vertical burning test(UL-94),TGA,SEM,and cone calorimeter test(CCT).The LOI value of the PP/MAPP composite at the same loading is higher than that of PP/APP composite.UL 94 ratings of PP/MAPP composites are raised to V-0 at 20 wt%loading.The results of CCT also show that MAPP is more efficient than APP.The morphological structures observed by digital photos and SEM demonstrated that MAPP could be promoted to form the continuous and compact intumescent char layer.The flame retardant mechanism of PP/MAPP is also discussed.展开更多
Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor perform...Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor performing enhanced biological phosphorus removal （EBPR） during start-up period. High phosphorus removal was achieved after 15 d. On day 30, phosphorus removal efficiency reached to 83.2% and the start-up was finished. DGGE profiles of periodical sludge samples showed that dominant microbial species were 19 OTUs （operational taxonomy units）. Unweighted pair-group method using arithmetic averages （UPGMA） clustering analysis revealed that rapid community succession correlated to low phosphorus removal rate and high phosphorus removal efficiency reflected on steady community structure. Sequencing results indicated that determined sequences （12 OTUs） belonged to Proteobacterium, Actinobacteria, Gemmatimonadales and unaffiliate group. Proteobacterium, Tetrasphaera elongate and Gemmatimonas aurantiaca may act important roles in phosphorus removal. With little amount as known glycogen accumulating organisms, Candidatus Competibacter phosphatis still at accumulating-phase had limited effect on microbial community structure. When climax community was obtained, dominant microbes were 14 OTUs. Microbes in a large amount were uncultured bacterium Thauera sp., uncultured y-Proteobacterium and Tetrasphaera elongata.展开更多
Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the ce...Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the cellular stoichiometry and phosphorus storage of microalgae under dif ferent turbulent mixing conditions. A phanizomenon flos-aquae were cultivated in dif ferent stirring batch reactors with turbulent dissipation rates ranging from 0.001 51 m2/s 3 to 0.050 58 m 2/s 3, the latter being the highest range observed in natural aquatic systems. Samples were taken in the exponential growth phase and compared with samples taken when the reactor was completely stagnant. Results indicate that, within a certain range, turbulent mixing stimulates the growth of A. flos-aquae. An inhibitory ef fect on growth rate was observed at the higher range. Photosynthesis activity, in terms of maximum ef fective quantum yield of PSII(the ratio of F v/F m) and cellular chlorophyll a, did not change significantly in response to turbulence. However, Chl a/C mass ratio and C/N molar ratio, showed a unimodal response under a gradient of turbulent mixing, similar to growth rate. Moreover, we found that increases in turbulent mixing might stimulate respiration rates, which might lead to the use of polyphosphate for the synthesis of cellular constituents. More research is required to test and verify the hypothesis that turbulent mixing changes the dif fusive sublayer, regulating the nutrient flux of cells.展开更多
The cure kinetics of diglycidyl ether of bisphenol A （DGEBA） with hyperbranched poly （3-hydroxyphenyl） phosphate（HHPP） as the curing agent was investigated by means of non-isothermal differential scanning calori...The cure kinetics of diglycidyl ether of bisphenol A （DGEBA） with hyperbranched poly （3-hydroxyphenyl） phosphate（HHPP） as the curing agent was investigated by means of non-isothermal differential scanning calorimetry （DSC） at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene（DHB） as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model（Sestak-Berggren equation） is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.展开更多
Starch has a wide range of sources and can be used as a high-quality precursor for sodium-ion battery anode materials.However,the carbonization yield and specific capacity of carbon materials obtained by directly pyro...Starch has a wide range of sources and can be used as a high-quality precursor for sodium-ion battery anode materials.However,the carbonization yield and specific capacity of carbon materials obtained by directly pyrolyzing starch are low.Herein,starch is used as the carbon source,and ammonium polyphosphate(APP)is used as the cross-linking agent and dopant to prepare a nitrogen and phosphorus co-doped porous carbon(NPPC).As the anode for sodium-ion batteries,NPPC-2 exhibits a high reversible capacity of 385.8 mAhg^(-1)at 50 mAg^(-1).Even after 1000 cycles at a large current density of 5 Ag^(-1),the reversible capacity can still be maintained at 126.9 mAhg^(-1).Based on detailed data and first-principles calculations,the excellent performance of NPPC is due to the effective doping of nitrogen and phosphorus elements,which distorts the graphite sheet,introduces defects,and increases the graphite layer spacing,thereby enhancing the adsorption capacity of the carbon material for sodium ions,reducing the diffusion barrier of sodium ions.This work provides a new idea for heteroatom doping and carbon material modification.展开更多
Ammonium phosphate fertilizer is the compounds containing nitrogen and phosphorus that are usually produced through the neutralization reaction of phosphoric acid and ammonia.At present,there are a variety of products...Ammonium phosphate fertilizer is the compounds containing nitrogen and phosphorus that are usually produced through the neutralization reaction of phosphoric acid and ammonia.At present,there are a variety of products,such as slurry monoammonium phosphate(MAP),diammonium phosphate(DAP),industrial grade MAP,water soluble MAP,water soluble ammonium polyphosphate(APP)and so on.After more than 60 years of development,China’s ammonium phosphate fertilizer industry has experienced the road of from scratch and from weak to strong.The successful development of the slurry MAP technology ended the history that the high concentration phosphate fertilizer cannot be produced by using the medium and low grade phosphate ore.The continuous,stable and large-scale production of DAP plant provides sufficient guarantee for DAP products in China.The development of new ammonium phosphate fertilizer products,such as industrial grade MAP,water soluble MAP,water soluble APP,provides technical support for the transformation and upgrading of phosphorus chemical enterprises.In this paper,the production methods,the development history and the latest research progress of ammonium phosphate fertilizers were reviewed.展开更多
To improve the flame-retardant efficiency and water resistance of ammonium polyphosphate（APP）, the UV-curable pentaerythritol triacrylate（PETA） was used to microencapsulate APP via the UV curing polymerization met...To improve the flame-retardant efficiency and water resistance of ammonium polyphosphate（APP）, the UV-curable pentaerythritol triacrylate（PETA） was used to microencapsulate APP via the UV curing polymerization method. The prepared PETA-microencapsulated APP（PETA-APP） was characterized by Fourier transform infrared spectroscopy（FTIR）, scanning electron microscopy（SEM）, and thermogravimetric（TG） analysis. PETA-APP was used as intumescent flame retardant（IFR） alone to flame retard polypropylene（PP）. The water resistance of PP/PETA-APP composites was investigated, and the effect of PETA on the combustion behaviors of PP/APP composites was studied through limiting oxygen index（LOI）, vertical burning test（UL-94） and cone calorimeter（CC） test, respectively. With 40 wt% of PETA-APP, the PP/PETA-APP system could achieve a LOI value of 30.0% and UL-94 V-0 rating after treatment in hot water for 168 h, while the LOI value of the system containing 40 wt% uncoated APP was only 19.2%, and it failed to pass the UL-94 rating. CC test results showed that the heat release rate（HRR）, mass loss rate（MLR） and smoke production rate（SPR） of PP/PETAAPP system decreased significantly compared with PP/APP system, especially the peak of HRR was decreased by 51.4%. The mechanism for the improvement of flame reatardancy for PP/PETA-APP composites was discussed based on FTIR and X-ray photoelectron spectroscopy（XPS） tests. All these results illustrated that simultaneous improvement of flame retardancy and water resistance for PP/APP was achieved through coating UV-curable PETA onto APP.展开更多
Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of commun...Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of community structure, abundance and seasonal population dynamics of Candidatus Accumulibacter to process operation of wastewater treatment plants（WWTPs） in China using ppk1 gene as phylogenetic marker. All sludge samples had properties of denitrifying P removal using nitrate as an electron acceptor.Accumulibacter abundance in the anaerobic-anoxic-oxic（A^2O） process was the highest（26%of total bacteria）, and higher in winter than in summer with a better EBPR performance.Type-II was the dominant Accumulibacter in all processes, and type-I accounted for a small proportion of total Accumulibacter. The abundance of Clade-IIC as the most dominant clade reached 2.59 × 10~9 cells/g MLSS and accounted for 87.3% of total Accumulibacter. Clade IIC mainly contributed to denitrifying P removal. Clades IIA, IIC and IID were found in all processes, while clade-IIF was only found in oxidation ditch process through phylogenetic analysis. High proportion of clade IID to total Accumulibacter led to poor performance of aerobic P-uptake in inverted A^2O process. Therefore, Accumulibacter clades in WWTPs were diverse, and EBPR performance was closely related to the clade-level community structures and abundances of Accumulibacter.展开更多
Polyvinyl alcohol (PVA) has been widely used in the fields of medical, food and packaging due to its excellentbiocompatibility, good fiber-forming and film-forming properties. However, the high flammability of PVA has...Polyvinyl alcohol (PVA) has been widely used in the fields of medical, food and packaging due to its excellentbiocompatibility, good fiber-forming and film-forming properties. However, the high flammability of PVA hasgreatly limited its wider applications. The flame-retardant PVA was prepared by melt blending of a bio-basedflame retardant (prepared from lignin, phosphoric acid and carbamide) with thermoplastic PVA (TPVA). Thechemical structure, morphology, thermal properties, mechanical properties, fire property and fluidity of thisflame retardant PVA were investigated by Fourier transform infrared spectrometer(FTIR), field emission scanning electron microscope(SEM), thermogravimetric analyzer(TGA), impact tester, universal testing machine,horizontal-vertical burning tester, limiting oxygen indexer(LOI) and melt flow rate meter(MFR). The resultsshowed that the prepared flame retardant had good compatibility with the PVA substrate;The impact strength,melt flow rate, fire property and char residue of this PVA material increased with the content of bio-based flameretardant. When the content of flame retardant was of 20%, the five indices including impact strength, meltflow rate, UL-94 level, LOI and char residual were 11.3 KJ/m^(2), 21.2 g/10 min, V-0 UL-94 level, 33.1%, and19.2%, respectively. This research can promote the high-value utilization of lignin and the application ofPVA in the fields of fire protection.展开更多
The flame-retardant properties of polyurethane(PU)containing ammonium polyphosphate(APP)and aluminum hydroxide(ATH)were investigated.Moreover,the flame retardant performance was investigated through thermogravimetric ...The flame-retardant properties of polyurethane(PU)containing ammonium polyphosphate(APP)and aluminum hydroxide(ATH)were investigated.Moreover,the flame retardant performance was investigated through thermogravimetric analysis,limiting oxygen index(LOI),vertical combustion(UL 94),and cone calorimeter.When 15 wt%APP and 5 wt%ATH were added together,the PU/15%APP/5%ATH sample shows better thermal stability and flame-retardant properties.When 15 wt%APP and 5 wt%ATH were added together,the LOI value of the PU/15%APP/5%ATH sample was 30.5%,and UL 94 V-0 rating was attained.Compared with PU,the peak heat release rate(PHRR),total heat release(THR),and average effective heat combustion(av-EHC)of the PU/15%APP/5%ATH sample decreased by 43.1%,21.0%,and 29.4%,respectively.In addition,the flame-retardant mechanism was investigated through cone calorimeter.The APP/ATH addition simultaneously exerted condensed phase and gas phase flame retardant effects.APP and ATH have synergistic flame retardant properties.展开更多
Two kinds of commercial ammonium polyphosphate （APP） and three kinds of APP which were prepared in the laboratory were studied by X-ray diffraction （XRD）, Fourier transforms infrared spectroscopy （FTIR）, scannin...Two kinds of commercial ammonium polyphosphate （APP） and three kinds of APP which were prepared in the laboratory were studied by X-ray diffraction （XRD）, Fourier transforms infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. In identification of the form Ⅱ crystal APP by XRD and FTIR, some discrepancies were discussed. It is pointed out that the absorbance of the FTIR spectra at 682 cm^-1 can exist not only in the form Ⅰ APP, but also in the form Ⅱ APP with the crystal lattice defects. The SEM images indicate that the form Ⅱ APP is of multilayer crystal structure. XRD and TEM can reveal the crystal lattice defects.展开更多
文摘Eight new polyphosphates containing both nucleic acid base and phosphonoacetic acid ethyl ester were synthesized by the polycondensation of P, P-dichloride of phosphonoacetic acid ethyl ester with 1, 3-dihydroxyalkyl-5-fluorouracil, 1,3-dihydroxyalkyl-uracil and 1,3-dihydroxyalkylthymine. These polyphosphates were tested against Ehrlich Ascites Carcinoma in mice. Polymer IIa and IIc exhibited excellent antitumor activity. IIc also showed lower toxicity.
文摘A new class of crosslinking polyphosphates were synthesized characterizedby IR 1HNMR, 31PNMR spectroscopy as well as elemental analysis. In vitrodegradation of the polyphosphates obtained and the release of antineoplastic drugMethotrexate (MTX) and contraceptive Levonorgestrel (LNG ) by nsing thesepolymers as matrix were studied. Zero order release rate was rkserved in the case ofLNG release.
基金supported by the National Key Research and Development Program of China(No.2023YFC2412300)the National Natural Science Foundation of China(Nos.82025025,U23A6008,U22A20162,and U21A2055)+3 种基金the Natural Science Foun-dation of Hebei Province of China(No.H2022202007)the Full-time Talents Program of Hebei Province of China(No.2020HBQZYC012)the Natural Science Foundation of Tianjin of China(Nos.21JCYBJC01380 and 21JCZDJC01110)the Scientific Research Project of Tianjin Education Commission(No.2022KJ096).
文摘In neurosurgery procedures,cerebrospinal fluid leakage is a commonly encountered complication.Re-constructing skull base defects with patch materials can reduce the risk of cerebrospinal fluid leakage which can lead to serious issues such as infection,meningitis,arachnoiditis,and delayed wound healing.An ideal skull base reconstruction material should not only serve as a leak-proof barrier but also pro-mote skull base bone regeneration.To fulfill this challenge,this research designed and fabricated a Janus orthogonal bilayer nanofiber membrane(OPCL/PG-PCPP).The aligned PCL(APCL)nanofibers were con-stituted as the top layer to resist cerebrospinal fluid leakage,while the perpendicular PCL/gelatin(APG)fibers with calcium polyphosphate encapsulated polydopamine nanoparticles(CPP@PDA,labeled as PCPP)were designed as the bottom layer(APG-PCPP)to facilitate osteoblast migration and osteogenic differen-tiation.Among these,APG-1%PCPP nanofibers demonstrated the most effective induction of osteogenic differentiation in bone marrow mesenchymal stem cells(rBMSCs).Subsequent in vivo animal experi-ments revealed that the bone surface area(BS),bone volume fraction(BV/TV),and number of trabec-ulae(Tb.N)in the APG-1%PCPP group were twice as high as those in the control group,which confirmed the good osteogenic potentials.Therefore,due to its unique leak-proof and osteoinductive properties,the OPCL/PG-PCPP membrane holds promise as an applicable skull base reconstruction material in the field of neurosurgery.
文摘Aging is considered the main risk factor for the development of several diseases,including the leading neurodegenerative disorders.While the cellular features of aging are complex and multifaceted,neuronal senescence has emerged as a major contributor and driver of this process in the mammalian cell.Cellular senescence is a programmed response to stress and irreparable damage,which drives the cell into an apoptosis-resistant,non-proliferative state.Senescent cells can also deleteriously affect neighboring,non-senescent cells.Senescence is a complex and multifaceted process associated with a wide range of cellular events,including the secretion of pro-inflammatory molecules and the arrest of the cell cycle.
基金supported by the National Research Foundation of Korea(NRF-2021R1A2C1008272)supported by the Institute of Information&communications Technology Planning&Evaluation(IITP)grant funded by the Korean government(MSIT)(No.2021-0-00259,Development of a Fast Wireless Charging System for Portable Terminals with improved heat dissipation and shielding performance)supported by the Applied Basic Research Program of Changzhou City(CJ20220030).
文摘Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.
基金supported by the National Natural Science Foundation of China(U23A20242 and U22A20523)the Fundamental Research Funds for the Central Universities under Grant 2023JCXK-01。
文摘Acinetobacter baumannii(A.baumannii)is well known for its virulence and persistence,particularly in intensive care units.Therefore,new strategies and candidates to treat A.baumannii infection are urgently needed considering the emergence of drug-resistant bacteria.Polyphosphate kinase 1(PPK1)is required for bacterial survival as it is involved in maintaining antibiotic resistance or tolerance,pathogenesis,and adversity resistance.Multiple phenotypic assays related to virulence and persistence were performed in this study,and phloretin was shown to attenuate A.baumannii virulence and persistence by inhibiting PPK1 activity.Phloretin hampered mobility,interfered with biofilm formation and decreased resistance to ampicillin,heat,and hydrogen peroxide stress in A.baumannii.The therapeutic effect was also examined in a mouse pneumonia infection model.Molecular simulation and site-directed mutagenesis revealed that ARG-22,MET-622,ASN-57,and ARG-65 were the sites of phloretin action against PPK1.Phloretin treatment led to changes in metabolic pathways associated with A.baumannii virulence and persistence,including glycerophospholipid metabolism and fatty acid biosynthesis.Furthermore,phloretin alleviated pneumonic injury in a mouse pneumonia infection model in vivo,indicating that phloretin is a promising compound for preventing A.baumannii infection resistance by targeting PPK1.
文摘The thermal behaviors and burning characteristics of reconstituted tobacco （RT） are strongly related with evolved gaseous products. The effect of ammonium polyphosphate （APP） as an additive of RT on the pyrolysis behavior and CO evolution was studied, emphasizing the role of heating velocity in reducing CO delivery of the mainstream smoke by APP. Thermogravimetric analysis （TGA） was employed to investigate the influence of APP on RT thermal behavior. Slow and flash pyrolysis of RT were compared to discuss the role of heating rate in decreasing CO by APP. TGA results demonstrated that, in dependence on APP concentration, APP influenced exothermal amount and weight loss rate during RT thermal decomposition, promoted the formation of char and retarded the thermal decomposition of RT. In addition, APP had a considerable influence on the evolution of gaseous products during thermal decomposition of RT. Both CO delivery per cigarette and that per puff in the smoking process were significantly reduced in dependence on APP content in RT. Comparative analysis of CO evolution patterns in the flash and slow pyrolysis elucidated that heating rate played a key role in decreasing CO evolution by APP. The results suggest that APP is a potential burning additive for controlling CO delivery in mainstream smoke of RT.
基金This project was supported by the National Natural Science Foundation of China.
文摘A series of novel polyphosphonates containing 5-flouro- N1-furanyl-N3- glyceroalkyl-uracil and formyl groups was synthesized by the condensation of 3-(w- (1-furanyl-5-flourouracil-3-yl) alkoxy)-1, 2-dihydroxy propane with phosphonyl dichloride. The products were characterized by IR, 1H NMR, 31P NMR, M, and elemental analysis. The results of bioassay show that compound 8a possesses potential anticancer activity.
文摘The ubiquitin-activating enzyme E1 (EC 6.3.2.19) represents the first step in the degradation of proteins by the ubiquitin proteasome pathway. E1 transfers ubiquitin from the ubiquitinated E1 to the ubiquitin carrier proteins (E2), ubiquitin-protein ligases (E3) and proteins. This process is rather complex, and known from the work of Haas, Ciechanover, Hershko, Rose and others. The occurrence of 19 hypothetical intermediate enzyme forms (EFs) and 22 different reactions were considered in the presence of ubiquitin (Ub), ATP, adenosine 5’-tetraphosphate (p4A), pyrophosphate (P2), and tripolyphosphate (P3) as substrates, and iodoacetamide (IAA) and dithioth- reitol (DTT) as inhibitors. Inspired by the work of Cha (Cha (1968) J. Biol. Chem., 243, 820-825) we have treated these reactions in two complementary ways: in rapid equilibrium and in steady state. The kinetics of both types of reactions were simulated and solved with a system of ordinary differential equations using the Mathematica Program. The ubiquitination of E1 has been also theoretically coupled to the ubiquitination of E2, E3 and proteins. This makes the model useful to predict the theoretical influence of inhibitors (or of changes in some parameters of the reaction) on the ubiquitination of proteins. The Program responds to changes in the concentration of ATP or ubiquitin and has predictive properties as shown by the influence of AMP on the synthesis of p4A, calculated theoretically and confirmed experimentally.
基金Supported by the Natural Science Foundation of Hebei Province(B2016209059)
文摘Dipentaerythritol(DPER),4,40-diphenylmethanediisocyanate(MDI)and melamine(MEL)are used as raw materials to microencapsulate ammonium polyphosphate(MAPP)in situ polymerization.The MAPP is characterized by Fourier transform infrared(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and thermal gravimetric analysis(TGA).The results show that the coating operation can effectively improve water resistance of ammonium polyphosphate(APP),and MAPP has higher residual rate than that of APP after combustion.The flame retardant action of MAPP and APP in polypropylene(PP)is investigated by the limited oxygen index(LOI),vertical burning test(UL-94),TGA,SEM,and cone calorimeter test(CCT).The LOI value of the PP/MAPP composite at the same loading is higher than that of PP/APP composite.UL 94 ratings of PP/MAPP composites are raised to V-0 at 20 wt%loading.The results of CCT also show that MAPP is more efficient than APP.The morphological structures observed by digital photos and SEM demonstrated that MAPP could be promoted to form the continuous and compact intumescent char layer.The flame retardant mechanism of PP/MAPP is also discussed.
基金supported by the National Natural Science Foundation of China (No. 50508011).
文摘Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor performing enhanced biological phosphorus removal （EBPR） during start-up period. High phosphorus removal was achieved after 15 d. On day 30, phosphorus removal efficiency reached to 83.2% and the start-up was finished. DGGE profiles of periodical sludge samples showed that dominant microbial species were 19 OTUs （operational taxonomy units）. Unweighted pair-group method using arithmetic averages （UPGMA） clustering analysis revealed that rapid community succession correlated to low phosphorus removal rate and high phosphorus removal efficiency reflected on steady community structure. Sequencing results indicated that determined sequences （12 OTUs） belonged to Proteobacterium, Actinobacteria, Gemmatimonadales and unaffiliate group. Proteobacterium, Tetrasphaera elongate and Gemmatimonas aurantiaca may act important roles in phosphorus removal. With little amount as known glycogen accumulating organisms, Candidatus Competibacter phosphatis still at accumulating-phase had limited effect on microbial community structure. When climax community was obtained, dominant microbes were 14 OTUs. Microbes in a large amount were uncultured bacterium Thauera sp., uncultured y-Proteobacterium and Tetrasphaera elongata.
基金Supported by the National Natural Science Foundation of China(Nos.51309220,51679226)the National Key SandT Project on Water Pollution Control and Treatment(Nos.2014ZX07104-006,2015ZX07103-007)the Western Action Program funded by the Chinese Academy of Sciences(No.KZCX2-XB3-14)
文摘Turbulent mixing, in particular on a small scale, aff ects the growth of microalgae by changing diff usive sublayers and regulating nutrient fluxes of cells. We tested the nutrient flux hypothesis by evaluating the cellular stoichiometry and phosphorus storage of microalgae under dif ferent turbulent mixing conditions. A phanizomenon flos-aquae were cultivated in dif ferent stirring batch reactors with turbulent dissipation rates ranging from 0.001 51 m2/s 3 to 0.050 58 m 2/s 3, the latter being the highest range observed in natural aquatic systems. Samples were taken in the exponential growth phase and compared with samples taken when the reactor was completely stagnant. Results indicate that, within a certain range, turbulent mixing stimulates the growth of A. flos-aquae. An inhibitory ef fect on growth rate was observed at the higher range. Photosynthesis activity, in terms of maximum ef fective quantum yield of PSII(the ratio of F v/F m) and cellular chlorophyll a, did not change significantly in response to turbulence. However, Chl a/C mass ratio and C/N molar ratio, showed a unimodal response under a gradient of turbulent mixing, similar to growth rate. Moreover, we found that increases in turbulent mixing might stimulate respiration rates, which might lead to the use of polyphosphate for the synthesis of cellular constituents. More research is required to test and verify the hypothesis that turbulent mixing changes the dif fusive sublayer, regulating the nutrient flux of cells.
文摘The cure kinetics of diglycidyl ether of bisphenol A （DGEBA） with hyperbranched poly （3-hydroxyphenyl） phosphate（HHPP） as the curing agent was investigated by means of non-isothermal differential scanning calorimetry （DSC） at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene（DHB） as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model（Sestak-Berggren equation） is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.
基金the National Natural Science Foundation of China(No.51872236)the Joint Fund Project-Enterprise-Shaanxi Coal Joint Fund Project(No.2019JLM32)。
文摘Starch has a wide range of sources and can be used as a high-quality precursor for sodium-ion battery anode materials.However,the carbonization yield and specific capacity of carbon materials obtained by directly pyrolyzing starch are low.Herein,starch is used as the carbon source,and ammonium polyphosphate(APP)is used as the cross-linking agent and dopant to prepare a nitrogen and phosphorus co-doped porous carbon(NPPC).As the anode for sodium-ion batteries,NPPC-2 exhibits a high reversible capacity of 385.8 mAhg^(-1)at 50 mAg^(-1).Even after 1000 cycles at a large current density of 5 Ag^(-1),the reversible capacity can still be maintained at 126.9 mAhg^(-1).Based on detailed data and first-principles calculations,the excellent performance of NPPC is due to the effective doping of nitrogen and phosphorus elements,which distorts the graphite sheet,introduces defects,and increases the graphite layer spacing,thereby enhancing the adsorption capacity of the carbon material for sodium ions,reducing the diffusion barrier of sodium ions.This work provides a new idea for heteroatom doping and carbon material modification.
文摘Ammonium phosphate fertilizer is the compounds containing nitrogen and phosphorus that are usually produced through the neutralization reaction of phosphoric acid and ammonia.At present,there are a variety of products,such as slurry monoammonium phosphate(MAP),diammonium phosphate(DAP),industrial grade MAP,water soluble MAP,water soluble ammonium polyphosphate(APP)and so on.After more than 60 years of development,China’s ammonium phosphate fertilizer industry has experienced the road of from scratch and from weak to strong.The successful development of the slurry MAP technology ended the history that the high concentration phosphate fertilizer cannot be produced by using the medium and low grade phosphate ore.The continuous,stable and large-scale production of DAP plant provides sufficient guarantee for DAP products in China.The development of new ammonium phosphate fertilizer products,such as industrial grade MAP,water soluble MAP,water soluble APP,provides technical support for the transformation and upgrading of phosphorus chemical enterprises.In this paper,the production methods,the development history and the latest research progress of ammonium phosphate fertilizers were reviewed.
基金financially supported by the National Natural Science Foundation of China(Nos.50933005,51121001)the Program for Changjiang Scholars and Innovative Research Team in Universities(IRT1026)
文摘To improve the flame-retardant efficiency and water resistance of ammonium polyphosphate（APP）, the UV-curable pentaerythritol triacrylate（PETA） was used to microencapsulate APP via the UV curing polymerization method. The prepared PETA-microencapsulated APP（PETA-APP） was characterized by Fourier transform infrared spectroscopy（FTIR）, scanning electron microscopy（SEM）, and thermogravimetric（TG） analysis. PETA-APP was used as intumescent flame retardant（IFR） alone to flame retard polypropylene（PP）. The water resistance of PP/PETA-APP composites was investigated, and the effect of PETA on the combustion behaviors of PP/APP composites was studied through limiting oxygen index（LOI）, vertical burning test（UL-94） and cone calorimeter（CC） test, respectively. With 40 wt% of PETA-APP, the PP/PETA-APP system could achieve a LOI value of 30.0% and UL-94 V-0 rating after treatment in hot water for 168 h, while the LOI value of the system containing 40 wt% uncoated APP was only 19.2%, and it failed to pass the UL-94 rating. CC test results showed that the heat release rate（HRR）, mass loss rate（MLR） and smoke production rate（SPR） of PP/PETAAPP system decreased significantly compared with PP/APP system, especially the peak of HRR was decreased by 51.4%. The mechanism for the improvement of flame reatardancy for PP/PETA-APP composites was discussed based on FTIR and X-ray photoelectron spectroscopy（XPS） tests. All these results illustrated that simultaneous improvement of flame retardancy and water resistance for PP/APP was achieved through coating UV-curable PETA onto APP.
基金supported by the National Key Research and Development Programme of China (No. 2016YFC0401103)the Natural Science Foundation of China (No. 51578016)the Natural Science Foundation of Beijing (No. 8172014)
文摘Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of community structure, abundance and seasonal population dynamics of Candidatus Accumulibacter to process operation of wastewater treatment plants（WWTPs） in China using ppk1 gene as phylogenetic marker. All sludge samples had properties of denitrifying P removal using nitrate as an electron acceptor.Accumulibacter abundance in the anaerobic-anoxic-oxic（A^2O） process was the highest（26%of total bacteria）, and higher in winter than in summer with a better EBPR performance.Type-II was the dominant Accumulibacter in all processes, and type-I accounted for a small proportion of total Accumulibacter. The abundance of Clade-IIC as the most dominant clade reached 2.59 × 10~9 cells/g MLSS and accounted for 87.3% of total Accumulibacter. Clade IIC mainly contributed to denitrifying P removal. Clades IIA, IIC and IID were found in all processes, while clade-IIF was only found in oxidation ditch process through phylogenetic analysis. High proportion of clade IID to total Accumulibacter led to poor performance of aerobic P-uptake in inverted A^2O process. Therefore, Accumulibacter clades in WWTPs were diverse, and EBPR performance was closely related to the clade-level community structures and abundances of Accumulibacter.
基金This work was financially supported by the following funds:National Natural Science Foundation of China(51803055)Hunan Provincial Natural Foundation of China(2019JJ50472)+5 种基金Scientific Research Fund of Hunan Provincial Education Department of China(18C0979,19A391)Opening Fund of National&Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources(KF201802)Hunan Province Key Field R&D Program Project(2019GK2246)Key Scientific Research Project of Huaihua University(HHUY2019-04)Hunan Provincial Key Research and Development Program(2018GK2062)Science and Technology Plan Project of Huaihua City(2020R3101).
文摘Polyvinyl alcohol (PVA) has been widely used in the fields of medical, food and packaging due to its excellentbiocompatibility, good fiber-forming and film-forming properties. However, the high flammability of PVA hasgreatly limited its wider applications. The flame-retardant PVA was prepared by melt blending of a bio-basedflame retardant (prepared from lignin, phosphoric acid and carbamide) with thermoplastic PVA (TPVA). Thechemical structure, morphology, thermal properties, mechanical properties, fire property and fluidity of thisflame retardant PVA were investigated by Fourier transform infrared spectrometer(FTIR), field emission scanning electron microscope(SEM), thermogravimetric analyzer(TGA), impact tester, universal testing machine,horizontal-vertical burning tester, limiting oxygen indexer(LOI) and melt flow rate meter(MFR). The resultsshowed that the prepared flame retardant had good compatibility with the PVA substrate;The impact strength,melt flow rate, fire property and char residue of this PVA material increased with the content of bio-based flameretardant. When the content of flame retardant was of 20%, the five indices including impact strength, meltflow rate, UL-94 level, LOI and char residual were 11.3 KJ/m^(2), 21.2 g/10 min, V-0 UL-94 level, 33.1%, and19.2%, respectively. This research can promote the high-value utilization of lignin and the application ofPVA in the fields of fire protection.
基金Supported by the Natural Science Foundation of Guangdong(Nos.2014A030313241,2014B090901068,and 2016A010103003).
文摘The flame-retardant properties of polyurethane(PU)containing ammonium polyphosphate(APP)and aluminum hydroxide(ATH)were investigated.Moreover,the flame retardant performance was investigated through thermogravimetric analysis,limiting oxygen index(LOI),vertical combustion(UL 94),and cone calorimeter.When 15 wt%APP and 5 wt%ATH were added together,the PU/15%APP/5%ATH sample shows better thermal stability and flame-retardant properties.When 15 wt%APP and 5 wt%ATH were added together,the LOI value of the PU/15%APP/5%ATH sample was 30.5%,and UL 94 V-0 rating was attained.Compared with PU,the peak heat release rate(PHRR),total heat release(THR),and average effective heat combustion(av-EHC)of the PU/15%APP/5%ATH sample decreased by 43.1%,21.0%,and 29.4%,respectively.In addition,the flame-retardant mechanism was investigated through cone calorimeter.The APP/ATH addition simultaneously exerted condensed phase and gas phase flame retardant effects.APP and ATH have synergistic flame retardant properties.
基金Sponsored by the National Key Technology R&D Program(2006BAE03B05-2)
文摘Two kinds of commercial ammonium polyphosphate （APP） and three kinds of APP which were prepared in the laboratory were studied by X-ray diffraction （XRD）, Fourier transforms infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. In identification of the form Ⅱ crystal APP by XRD and FTIR, some discrepancies were discussed. It is pointed out that the absorbance of the FTIR spectra at 682 cm^-1 can exist not only in the form Ⅰ APP, but also in the form Ⅱ APP with the crystal lattice defects. The SEM images indicate that the form Ⅱ APP is of multilayer crystal structure. XRD and TEM can reveal the crystal lattice defects.
