This study aimed to establish a highly accurate method for quantifying methotrexate(MTX)concentrations in serum using an ultra-high performance liquid chromatography-tandem mass spectrometry system(UPLC-MS/MS)and to c...This study aimed to establish a highly accurate method for quantifying methotrexate(MTX)concentrations in serum using an ultra-high performance liquid chromatography-tandem mass spectrometry system(UPLC-MS/MS)and to compare its performance with the chemiluminescence microparticle immunoassay(CMIA).A total of 211 serum samples from pediatric patients with intracranial tumors undergoing high-dose MTX treatment were analyzed using both techniques.Correlation and agreement analyses were performed to assess the level of concordance between these methods.The results demonstrated a significant correlation(P<0.05)between the two methods,with correlation coefficients of 0.9913 and 0.9893,respectively.However,a statistical difference was noted in MTX serum concentrations at lower levels(0.04-1.5μmol/L),while no significant difference was observed at higher concentrations(1.5-400μmol/L).Specifically,in the 0.04-1.5μmol/L range(107 cases),Bland-Altman analysis indicated a bias of 0.018 between the two methods.Given the observed discrepancies,particularly at lower concentrations,it is advised that the UPLC-MS/MS method should not be used interchangeably with the CMIA assay for therapeutic drug monitoring in patients receiving high-dose MTX treatment.展开更多
Article continues and complements our previous articles on the HM16 ether (ETH) model. Here, we describe the mechanism of occurrence of the submicroparticle (SMP). A general hypothesis, HFVI, is introduced for the mod...Article continues and complements our previous articles on the HM16 ether (ETH) model. Here, we describe the mechanism of occurrence of the submicroparticle (SMP). A general hypothesis, HFVI, is introduced for the modalities of interaction between two SMPs, based on periodic mechanical percussion forces, produced by fundamental vibrations FVs. A mechanism for describing the interaction between a SMPs and the ETH is presented. Positive and negative particles are defined by their membrane types of movement, such as +, <span style="white-space:nowrap;">−</span><em>u</em>/+, <span style="white-space:nowrap;">−</span><em>v</em> vibrations, and rotations at speeds +<span style="white-space:nowrap;">Ω</span>/<span style="white-space:nowrap;">−</span><span style="white-space:nowrap;">Ω</span>. The process of creating a pair of SMPs is discussed. Applying HFVI to the interaction between pairs of SMPs immobile in ETH, and considering longitudinal FVL, was obtained the forces of attraction/repulsion +<em>F</em><sub><em>L</em>21</sub>/–<em>F<sub>L</sub></em><sub>21</sub>, which correspond to the completed Coulomb force<em> F<sub>CC</sub></em> including gravitation. The resultant <em>F</em><sub>RL21</sub> will form an oriented field of forces, which is a quasielectric field <em>QE</em>, equivalent to actual <em>E</em> electric field. Considering transversal FVT, was obtained the vibratory forces +, <span style="white-space:nowrap;">−</span><em>F<sub>T</sub></em><sub>21</sub>, whose resultant forms an vibrating field of forces, <em>QHs</em>, a quasimagnetic special field, which may explain some of the quantum properties of SMPs. Considering a mobile SMP, two new<em> <span style="white-space:nowrap;">γ</span></em> strains in ETH appear. Strains <em><span style="white-space:nowrap;">γ</span><sub>L</sub></em> are created by the displacement of SMP with velocity<em> V</em>, whose force +, <span style="white-space:nowrap;">−</span><em>F<sub>T</sub></em><sub>12</sub> is the support of a component of the magnetic field <em>H</em> (quasimagnetic field <em>QH</em>), giving the <em>QH<sub>L</sub></em> component. Strains <em>γ</em><sub>R</sub> are created by the rotation of SMP with speed <span style="white-space:nowrap;">Ω</span>, whose force +, <span style="white-space:nowrap;">−</span><em>F</em><sub>R12</sub> constitutes physical support of the component <em>QH<sub>R</sub></em> of magnetic field <em>H </em>(<em>i.e. QH)</em><em></em>. The creation of a photon PH is modelled as a special ESMP containing two zones of opposed rotations, and a mechanism is presented for its movement in the ETH with speed <em>c</em> based on the HS hypothesis of screwing in ETH, with frequency <em>ν</em>.展开更多
Microparticle formation and crystallization rate of 1,3,5,7-tetranitro-l,3,5,7-tetraazacyclooctane (HMX) in acetone solution using supercritical carbon dioxide antisolvent (GAS) recrystallization were studied. Scannin...Microparticle formation and crystallization rate of 1,3,5,7-tetranitro-l,3,5,7-tetraazacyclooctane (HMX) in acetone solution using supercritical carbon dioxide antisolvent (GAS) recrystallization were studied. Scanning electronic microscopy, X-ray diffraction and infrared radiation were used to examine particle size, crystallinity and chemical structure. The results show that B-HMX microparticle in different average size (2-9.5um) and with narrow size distribution were obtained by controlling the expansibility, expansion speed, initial concentration and temperature during recrystallization of HMX. The formation of nuclei may be a main cause of consumption of solute when the solution is expanded rapidly enough and the equilibrium concentration is lower, in which almost monodisperse microparticle can be obtained.展开更多
The auto-gelling and drug release properties of the thermosensitive chitosan-β-glycerophosphate formulation were investigated. According to rheological study, gelation lag time of chitosan/β-glycerophosphate （GP） ...The auto-gelling and drug release properties of the thermosensitive chitosan-β-glycerophosphate formulation were investigated. According to rheological study, gelation lag time of chitosan/β-glycerophosphate （GP） solutions varied from 2 to 60min with different deacetylation degree of chitosan, pH, gelation temperature, and the particles in the sol. The gelation properties were also found to influence the release profilles of a hydrophilic drug, 5-fluorouracil （5-FU）. Morphological examination by scanning electron microphotography demonstrated that large ＂pores＂ occurred during the gel-forming process, which created hydrophilic environment and led to the rapid initial release of the drug （85% in f＇LrSt 8h）. Poly-3-hydroxybutyrate （PHB）, a biodegradable material, was applied here as scaffold to capture 5-FU into microparticles with high encapsulation efficiency by solvent-nonsolvent method. Combination of these microparticles into the chitosan-β-GP formulation could drop the rapid initial release from 85% down to 29% in the optimized PHB content （75%, by mass）. The release could sustain for about 10 months. Tiffs study provided an understanding of the potential of injectable implant using thermosensitive chitosan-β-GP formulation containing PHB based particles for the water soluble drugs that need the property of long-term delivery.展开更多
Platelet microparticles(PMPs)are membrane particles derived from the platelet membrane that enter into the blood circulation.We sought to explore the therapeutic effects of Tao-Hong-Si-Wu Decoction(THSWD)on angiogenes...Platelet microparticles(PMPs)are membrane particles derived from the platelet membrane that enter into the blood circulation.We sought to explore the therapeutic effects of Tao-Hong-Si-Wu Decoction(THSWD)on angiogenesis in a rat model of cerebral ischaemia-reperfusion(I/R).The protective effect of THSWD on I/R rats was observed morphologically by immunohistochemical expression of VEGF and CD34,along with immunofluorescence results of co-expression of Brd U and v WF.Then,PMPs from different groups of rats were extracted,and cytokine array analysis was used to screen for angiogenesis associated proteins.The results showed that THSWD can promote the expression of VEGF,CD34,Brd U and v WF.Cytokine array analysis revealed the changes in the expression of 29 related angiogenic proteins in the total protein of PMPs,which involved the Notch signalling pathway.Compared with model group,the expression levels of NICD and Hes-1 in the THSWD group were significantly increased.In the context of I/R,the angiogenesis-related proteins of PMPs are different.THSWD may involve the promotion of activation of the Notch signalling pathway to achieve therapeutic effects on cerebral ischaemia.展开更多
Microparticles are small cell vesicles that can be released by almost all eukaryotic cells during cellular stress and cell activation. Within the last 1-2 decades it has been shown that microparticles are useful blood...Microparticles are small cell vesicles that can be released by almost all eukaryotic cells during cellular stress and cell activation. Within the last 1-2 decades it has been shown that microparticles are useful blood surrogate markers for different pathological conditions, such as vascular inflammation, coagulation and tumour diseases. Several studies have investigated the abundance of microparticles of different cellular origins in multiple cardiovascular diseases. It thereby has been shown that microparticles released by platelets, leukocytes and endothelial cells can be found in conditions of endothelial dysfunction, acute and chronic vascular inflammation and hypercoagulation. In addition to their function as surrogate markers, several studies indicate that circulating microparticles can fuse with distinct target cells, such as endothelial cells or leukocyte, and thereby deliver cellular components of their parental cells to the target cells. Hence, microparticles are a novel entity of circulating, paracrine, biological vectors which can influence the phenotype, the function and presumably even the transcriptome of their target cells.This review article aims to give a brief overview about the microparticle biology with a focus on endothelial activation and arterial hypertension. More detailed information about the role of microparticles in pathophysiology and disease can be found in already published work.展开更多
Ultra-thin flexible films have attracted wide attention because of their excellent ductility and potential versatility.In particular,the energy-harvesting films(EHFs)have become a research hotspot because of the indis...Ultra-thin flexible films have attracted wide attention because of their excellent ductility and potential versatility.In particular,the energy-harvesting films(EHFs)have become a research hotspot because of the indispensability of power source in various devices.However,the design and fabrication of such films that can capture or transform di erent types of energy from environments for multiple usages remains a challenge.Herein,the multifunctional flexible EHFs with e ective electro-/photo-thermal abilities are proposed by successive spraying Ag microparticles and MXene suspension between on waterborne polyurethane films,supplemented by a hot-pressing.The optimal coherent film exhibits a high electrical conductivity(1.17×10^(4)S m^(-1)),excellent Joule heating performance(121.3℃)at 2 V,and outstanding photo-thermal performance(66.2℃ within 70 s under 100 mW cm^(-1)).In addition,the EHFs-based single-electrode triboelectric nanogenerators(TENG)give short-circuit transferred charge of 38.9 nC,open circuit voltage of 114.7 V,and short circuit current of 0.82μA.More interestingly,the output voltage of TENG can be further increased via constructing the double triboelectrification layers.The comprehensive ability for harvesting various energies of the EHFs promises their potential to satisfy the corresponding requirements.展开更多
A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELI...A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).展开更多
The work presents microparticle concentrations in snowpits from the East Rongbuk Glacier on Mt. Qomolangma (Everest) (ER) (28.02°N, 86.96°E, 6536 m a.s.l.), the Zhadang Glacier on Mt. Nyainqentanglha (NQ) (3...The work presents microparticle concentrations in snowpits from the East Rongbuk Glacier on Mt. Qomolangma (Everest) (ER) (28.02°N, 86.96°E, 6536 m a.s.l.), the Zhadang Glacier on Mt. Nyainqentanglha (NQ) (30.47°N, 90.65°E, 5800m a.s.l.), and the Guoqu Glacier on Mt. Geladaindong (GL) (33.95°N, 91.28°E, 5823m a.s.l.) over the Tibetan Plateau (TP). Variations of microparticle and major ions (e.g. Mg2+, Ca2+) concentrations in snowpits show that the values of the microparticles and ions in the non-monsoon seasons are much higher than those in the monsoon seasons. Annual flux of microparticle deposition at ER is lower than those at NQ and GL, which could be attributed to the long distance away from the possible dust source regions as well as the elevation for ER higher than the others. Compared with other remote areas, microparticle concentrations in the southern TP are much lower than those in the northern TP, but still much higher than those in Greenland and Antarctica. The seasonal and spatial microparticle variations are clearly related to the variations of atmospheric circulation according to the air mass 5-day backward trajectory analyses of HYSPLIT Model. Resultingly, the high microparticle values in snow are mainly attributed to the westerlies and the strong dust storm outbreaks on the TP, while the monsoon circulation brings great amount of precipitation from the Indian Ocean, thus reducing in the aerosol concentrations.展开更多
Supercritical antisolvent (SAS) process is a recently developed technology to produce micro- and nano particles. This paper presents a continuous apparatus to conduct experiment of SAS process. With the apparatus, the...Supercritical antisolvent (SAS) process is a recently developed technology to produce micro- and nano particles. This paper presents a continuous apparatus to conduct experiment of SAS process. With the apparatus, the effects of pressure, temperature and flow ratio of CO2 to the solution on the shape and size of particles are studied for the quercetin-ethanol-CO2 system. Spherical quercetin microparticles with diameters ranging form 1 μm to 6μm can be obtained while ethanol is used as organic solvent. The most effective fact on the shape and size of particles is pressure, the next is temperature and the last is the flow ratio of CO2 to solution.展开更多
An emulsion-congealing technique is used to prepare solid lipid microparticles （SLM） containing ibuprofen with glyceryl behenate, tripalmitin and beewax as excipients. The difference of the solubility parameters bet...An emulsion-congealing technique is used to prepare solid lipid microparticles （SLM） containing ibuprofen with glyceryl behenate, tripalmitin and beewax as excipients. The difference of the solubility parameters between the excipients and ibuprofen are used to analyze their compatibility. Both the solubility parameter analysis and the experimental results show that glyceryl behenate is the best among the three excipients. The solid particles disperse well in aqueous phase when the drug loading reaches 10% （relative to lipid only）. Glycerides exhibit marked polymorphism and their rapid rates of crystallization accelerate the formation of metastable crystal modification. The metastable crystal modification characterizes high drug loading capacity but less stability. Increasing the content of lipophilic drug in a lipid matrix facilitates the transformation of excipients to more stable polymorphic forms.展开更多
Si is a promising anode material for Li ion batteries because of its high specific capacity,abundant reserve,and low cost.However,its rate performance and cycling stability are poor due to the severe particle pulveriz...Si is a promising anode material for Li ion batteries because of its high specific capacity,abundant reserve,and low cost.However,its rate performance and cycling stability are poor due to the severe particle pulverization during the lithiation/delithiation process.The high stress induced by the Li concentration gradient and anisotropic deformation is the main reason for the fracture of Si particles.Here we present a new stress mitigation strategy by uniformly distributing small amounts of Sn and Sb in Si micron-sized particles,which reduces the Li concentration gradient and realizes an isotropic lithiation/delithiation process.The Si8.5Sn0.5Sb microparticles(mean particle size:8.22μm)show over 6000-fold and tenfold improvements in electronic conductivity and Li diffusivity than Si particles,respectively.The discharge capacities of the Si_(8.5)Sn_(0.5)Sb microparticle anode after 100 cycles at 1.0 and 3.0 A g^(-1)are 1.62 and 1.19 Ah g^(-1),respectively,corresponding to a retention rate of 94.2%and 99.6%,respectively,relative to the capacity of the first cycle after activation.Multicomponent microparticle anodes containing Si,Sn,Sb,Ge and Ag prepared using the same method yields an ultra-low capacity decay rate of 0.02%per cycle for 1000 cycles at 1 A g^(-1),corroborating the proposed mechanism.The stress regulation mechanism enabled by the industry-compatible fabrication methods opens up enormous opportunities for low-cost and high-energy-density Li-ion batteries.展开更多
ABSTRACT： Samples were continuously collected from aerosol, fresh snow, and snow pits on Glacier No. 1 at Urumqi River source in eastern Tianshan （天山） Mountains. The deposition processes and the characteristics o...ABSTRACT： Samples were continuously collected from aerosol, fresh snow, and snow pits on Glacier No. 1 at Urumqi River source in eastern Tianshan （天山） Mountains. The deposition processes and the characteristics of mineral dust microparticles from aerosol to fresh snow, and then evolution to the snow pit were determined. Total dust microparticle concentration in the surface snow and aerosol showed a similar temporal variation trend, which was strongly associated with regional and local at- mospheric circulation in the Tianshan Mountains region of Central Asia. Especially from November to February, the correlation coefficient of microparticles concentration in surface snow and aerosol is very high （R2=0.7）. Vertical profiles of microparticles in the snow pits showed that observed dust layers were in high correlation with concentration peaks of large microparticles （d〉10 μm）, but low correlation with that of fine microparticles （d〈1μm）. Moreover, explicit post-depositional process of dust particles was studied by tracking some typical dust concentration peaks in the snow pit. We find that late sum- mer is a key period for post-deposition of dust particles in the snow, as particle concentration peaks in the snow pit evolve intensely during this period. Such evolutional pattern of large particles makes it possible to preserve information of atmospheric dust in the snow, which offers an available proof to reconstruct historical climate using ice cores on Glacier No. 1 and other gla- ciers in the Tianshan Mountains.展开更多
Ultrafine-grained(UFG)/nanocrystalline materials possess novel properties. Refining as-solidified grains of metals to the ultrafine and even nanometer scale by nanoparticles via slow cooling has been recently discover...Ultrafine-grained(UFG)/nanocrystalline materials possess novel properties. Refining as-solidified grains of metals to the ultrafine and even nanometer scale by nanoparticles via slow cooling has been recently discovered. Here, we report that microparticles(CrB and CrB_(2)) with surface nanofeatures can also enable ultrafine/nano grains via slow cooling. CrB/CrB_(2) microparticles, formed by coalescence of nanoparticles in Cu matrix, display surface nanofeatures, which induce substantial grain refinement and stabilization down to the ultrafine/nano scale. The UFG Cu/Cr B and Cu/CrB_(2) samples exhibit exceptional thermal stability, comparable to UFG Cu induced by nanoparticles, without coarsening after annealing at 600°C for 1 h. The microhardness, strengths, and Young's moduli of the Cu/Cr B and Cu/CrB_(2) samples are significantly enhanced over pure Cu. This discovery has great potential to advance the mass production UFG/nanocrystalline for widespread applications.展开更多
A type of triangular pyramid-shaped microparticles of puerarin was synthesized by using oil-in-oil microemulsion approach which is simple and economical under the action of copper substrate.The pyramid-shaped micropar...A type of triangular pyramid-shaped microparticles of puerarin was synthesized by using oil-in-oil microemulsion approach which is simple and economical under the action of copper substrate.The pyramid-shaped microparticles would be made up of deposit of nanospheres or nanorods and have two significant characters.One is its complex surface morphology like coral reef.The other is a lot of nanopores in existence in the microparticle body.Two possible formation routes were speculated.展开更多
The deoiled asphalt as the carbon source and the ferrocene as the metal source and the catalyst precursor were chosen to synthesize iron-containing carbon microparticles through co-carbonization at the temperature of ...The deoiled asphalt as the carbon source and the ferrocene as the metal source and the catalyst precursor were chosen to synthesize iron-containing carbon microparticles through co-carbonization at the temperature of about 450℃ for 3 h. The resulting products were treated at 2 000 ℃ for 2 h. All samples were examined by high resolution transmission electron microscopy （HRTEM） and X-ray diffraction （XRD）. The results show that the iron particles in the heat-treated material are completely coated by carbon. In addition to the fully filled carbon microparticles as well as hollow carbon ones, also form carbon fibers with hollow centers. The formation mechanism of the as-prepared products was discussed briefly.展开更多
AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascu...AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascular disease,and 12 healthy controls were subjected to measurement of baseline platelet CD62 P, CD63 and CD42 b expression, platelet-leukocyte complexes, i.e., platelet-monocyte complexes(PMC), platelet-neutrophil complexes(PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles(PMPs) using flow cytometry. Both larger-size(0.5-0.9 μm) and smallersize(< 0.5 μm) PMPs were determined. Serum interleukin(IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index(PASI).RESULTS PMP concentrations were significantly higher in psoriasis patients than controls [mean±standard error of mean(SEM): 22±5/μL vs 11±6/μL; P=0.018), for both smaller-size(10±2/μL vs 4±2/μL; P=0.033) and larger-size(12±3/μL vs 6±4/μL; P=0.014) PMPs. Platelet CD62 P, CD63 and CD42 b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls(mean±SEM: 16%±3% vs 23%±6%; P=0.047). Larger-size PMPs were related with IL-12 levels(P<0.001) and smaller-size PMPs with both IL-12 and IL-17 levels(P<0.001). Total PMPs also correlated with IL-12(P<0.001). CD63 expression was positively correlated with both IL-12 and IL-17(P<0.05). Increased PASI score was associated with increased levels of larger-size PMPs(r=0.45; P=0.011) and increased CD63 expression(r=0.47; P<0.01).CONCLUSION PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.展开更多
Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extra...Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.展开更多
In current work,Ni-Ti-CeO_(2) nanocomposite coatings were achieved by co-adding Ti microparticles and CeO_(2) nanoparticles.Designed experiments and COMSOL computer simulation were applied to reveal the synergistic ro...In current work,Ni-Ti-CeO_(2) nanocomposite coatings were achieved by co-adding Ti microparticles and CeO_(2) nanoparticles.Designed experiments and COMSOL computer simulation were applied to reveal the synergistic role of Ti microparticles and CeO_(2) nanoparticles in tailoring the spatial microstructures and properties of Ni-Ti-CeO_(2) nanocomposite coating.Unilaterally,the conductive Ti microparticles conducted the growth behavior of Ni grains by current density concentration,distorting electronic feld lines and heterogeneous nucleation.Individual domains consisting of inner nanograins and outer radial columnar grains surrounded Ti microparticles,where Ti microparticles acted as seeds.Ti microparticles tended to be aggregated,leading to spatial heterogeneity of microstructures.Ni deposits buried the Ti microparticles in forms of“covering model”,contributing to the formation of inside voids and rough surface and aggregation of Ti microparticles;on the other hand,the non-conductive CeO_(2)microparticles hardly changed the distribution of current density and electronic feld lines on the cathode surface.Ni deposits buried the CeO_(2)microparticle in forms of“stacking model”,avoiding the inside voids and aggregation of particles.The incorporation of CeO_(2)microparticle brought in microstructure evolutions only on its top side without disturbing the growth behavior of Ni grains on its lateral side or bottom,suggesting the limited effects.This was correlated with the presence of current concentration above the CeO_(2) microparticle at the last stage of burying CeO_(2) microparticle.The co-addition of Ti microparticles and CeO_(2) nanoparticles into Ni deposits exploited the complementary action of the two particles,which gave birth to satisfed spatial microstructures and improved hardness.Ti microparticles took major responsibility for microstructure evolutions,while the CeO_(2) nanoparticles were mainly in charge of the microstructure homogeneity.展开更多
Hypromellose acetate succinate(HPMCAS) microparticles containing the poorly-water soluble drug celecoxib(CEL) were prepared by electrospraying intended for oral drug delivery. Various solvent mixtures with different s...Hypromellose acetate succinate(HPMCAS) microparticles containing the poorly-water soluble drug celecoxib(CEL) were prepared by electrospraying intended for oral drug delivery. Various solvent mixtures with different solubility for CEL and HPMCAS were used to induce changes in the polymer structural conformation of the microparticles. The performance of the prepared microparticles was evaluated by studying the solid state from, particle size and morphology, radial drug distribution and drug release. CEL was amorphous in all electrosprayed HPMCAS microparticles. The particle size and morphology was dependent on the solubility of HPMCAS in the solvent mixture used with poorer solvents resulting in smaller microparticles with rougher appearance. The CEL distribution on the particles surface was relatively homogeneous and similar for all microparticles. Drug release from the microparticles was observed at a higher rate depending on the solubility of HPMCAS in the solvent used for electrospraying, and in all cases an at least 4-fold higher rate was observed compared with the crystalline drug. Drug precipitation from the supersaturated solution was inhibited by HPMCAS for all microparticles based on its parachute effect while crystalline CEL did not reach supersaturation. This study demonstrated that electrospraying can be used to produce microparticles with tailored properties for pharmaceutical application by adjusting solvent selection.展开更多
基金The Science and Technology Fund of Beijing Shijitan Hospital(Grant No.2022-C06)the National Key Research and Development Program of China(Grant No.2020YFF01014606).
文摘This study aimed to establish a highly accurate method for quantifying methotrexate(MTX)concentrations in serum using an ultra-high performance liquid chromatography-tandem mass spectrometry system(UPLC-MS/MS)and to compare its performance with the chemiluminescence microparticle immunoassay(CMIA).A total of 211 serum samples from pediatric patients with intracranial tumors undergoing high-dose MTX treatment were analyzed using both techniques.Correlation and agreement analyses were performed to assess the level of concordance between these methods.The results demonstrated a significant correlation(P<0.05)between the two methods,with correlation coefficients of 0.9913 and 0.9893,respectively.However,a statistical difference was noted in MTX serum concentrations at lower levels(0.04-1.5μmol/L),while no significant difference was observed at higher concentrations(1.5-400μmol/L).Specifically,in the 0.04-1.5μmol/L range(107 cases),Bland-Altman analysis indicated a bias of 0.018 between the two methods.Given the observed discrepancies,particularly at lower concentrations,it is advised that the UPLC-MS/MS method should not be used interchangeably with the CMIA assay for therapeutic drug monitoring in patients receiving high-dose MTX treatment.
文摘Article continues and complements our previous articles on the HM16 ether (ETH) model. Here, we describe the mechanism of occurrence of the submicroparticle (SMP). A general hypothesis, HFVI, is introduced for the modalities of interaction between two SMPs, based on periodic mechanical percussion forces, produced by fundamental vibrations FVs. A mechanism for describing the interaction between a SMPs and the ETH is presented. Positive and negative particles are defined by their membrane types of movement, such as +, <span style="white-space:nowrap;">−</span><em>u</em>/+, <span style="white-space:nowrap;">−</span><em>v</em> vibrations, and rotations at speeds +<span style="white-space:nowrap;">Ω</span>/<span style="white-space:nowrap;">−</span><span style="white-space:nowrap;">Ω</span>. The process of creating a pair of SMPs is discussed. Applying HFVI to the interaction between pairs of SMPs immobile in ETH, and considering longitudinal FVL, was obtained the forces of attraction/repulsion +<em>F</em><sub><em>L</em>21</sub>/–<em>F<sub>L</sub></em><sub>21</sub>, which correspond to the completed Coulomb force<em> F<sub>CC</sub></em> including gravitation. The resultant <em>F</em><sub>RL21</sub> will form an oriented field of forces, which is a quasielectric field <em>QE</em>, equivalent to actual <em>E</em> electric field. Considering transversal FVT, was obtained the vibratory forces +, <span style="white-space:nowrap;">−</span><em>F<sub>T</sub></em><sub>21</sub>, whose resultant forms an vibrating field of forces, <em>QHs</em>, a quasimagnetic special field, which may explain some of the quantum properties of SMPs. Considering a mobile SMP, two new<em> <span style="white-space:nowrap;">γ</span></em> strains in ETH appear. Strains <em><span style="white-space:nowrap;">γ</span><sub>L</sub></em> are created by the displacement of SMP with velocity<em> V</em>, whose force +, <span style="white-space:nowrap;">−</span><em>F<sub>T</sub></em><sub>12</sub> is the support of a component of the magnetic field <em>H</em> (quasimagnetic field <em>QH</em>), giving the <em>QH<sub>L</sub></em> component. Strains <em>γ</em><sub>R</sub> are created by the rotation of SMP with speed <span style="white-space:nowrap;">Ω</span>, whose force +, <span style="white-space:nowrap;">−</span><em>F</em><sub>R12</sub> constitutes physical support of the component <em>QH<sub>R</sub></em> of magnetic field <em>H </em>(<em>i.e. QH)</em><em></em>. The creation of a photon PH is modelled as a special ESMP containing two zones of opposed rotations, and a mechanism is presented for its movement in the ETH with speed <em>c</em> based on the HS hypothesis of screwing in ETH, with frequency <em>ν</em>.
基金the National Natural Science Foundation of China (No. 29376233).
文摘Microparticle formation and crystallization rate of 1,3,5,7-tetranitro-l,3,5,7-tetraazacyclooctane (HMX) in acetone solution using supercritical carbon dioxide antisolvent (GAS) recrystallization were studied. Scanning electronic microscopy, X-ray diffraction and infrared radiation were used to examine particle size, crystallinity and chemical structure. The results show that B-HMX microparticle in different average size (2-9.5um) and with narrow size distribution were obtained by controlling the expansibility, expansion speed, initial concentration and temperature during recrystallization of HMX. The formation of nuclei may be a main cause of consumption of solute when the solution is expanded rapidly enough and the equilibrium concentration is lower, in which almost monodisperse microparticle can be obtained.
基金Supported by the National Natural Science Foundation of China (No.20376038) and the Research Foundation of the Ministry ofEducation of China (No.2002003056).
文摘The auto-gelling and drug release properties of the thermosensitive chitosan-β-glycerophosphate formulation were investigated. According to rheological study, gelation lag time of chitosan/β-glycerophosphate （GP） solutions varied from 2 to 60min with different deacetylation degree of chitosan, pH, gelation temperature, and the particles in the sol. The gelation properties were also found to influence the release profilles of a hydrophilic drug, 5-fluorouracil （5-FU）. Morphological examination by scanning electron microphotography demonstrated that large ＂pores＂ occurred during the gel-forming process, which created hydrophilic environment and led to the rapid initial release of the drug （85% in f＇LrSt 8h）. Poly-3-hydroxybutyrate （PHB）, a biodegradable material, was applied here as scaffold to capture 5-FU into microparticles with high encapsulation efficiency by solvent-nonsolvent method. Combination of these microparticles into the chitosan-β-GP formulation could drop the rapid initial release from 85% down to 29% in the optimized PHB content （75%, by mass）. The release could sustain for about 10 months. Tiffs study provided an understanding of the potential of injectable implant using thermosensitive chitosan-β-GP formulation containing PHB based particles for the water soluble drugs that need the property of long-term delivery.
基金supported by the National Natural Science Foundation of China(Nos.81473387 and 81503291)the Anhui Province Key Research and Development Program(No.1704a0802141)。
文摘Platelet microparticles(PMPs)are membrane particles derived from the platelet membrane that enter into the blood circulation.We sought to explore the therapeutic effects of Tao-Hong-Si-Wu Decoction(THSWD)on angiogenesis in a rat model of cerebral ischaemia-reperfusion(I/R).The protective effect of THSWD on I/R rats was observed morphologically by immunohistochemical expression of VEGF and CD34,along with immunofluorescence results of co-expression of Brd U and v WF.Then,PMPs from different groups of rats were extracted,and cytokine array analysis was used to screen for angiogenesis associated proteins.The results showed that THSWD can promote the expression of VEGF,CD34,Brd U and v WF.Cytokine array analysis revealed the changes in the expression of 29 related angiogenic proteins in the total protein of PMPs,which involved the Notch signalling pathway.Compared with model group,the expression levels of NICD and Hes-1 in the THSWD group were significantly increased.In the context of I/R,the angiogenesis-related proteins of PMPs are different.THSWD may involve the promotion of activation of the Notch signalling pathway to achieve therapeutic effects on cerebral ischaemia.
文摘Microparticles are small cell vesicles that can be released by almost all eukaryotic cells during cellular stress and cell activation. Within the last 1-2 decades it has been shown that microparticles are useful blood surrogate markers for different pathological conditions, such as vascular inflammation, coagulation and tumour diseases. Several studies have investigated the abundance of microparticles of different cellular origins in multiple cardiovascular diseases. It thereby has been shown that microparticles released by platelets, leukocytes and endothelial cells can be found in conditions of endothelial dysfunction, acute and chronic vascular inflammation and hypercoagulation. In addition to their function as surrogate markers, several studies indicate that circulating microparticles can fuse with distinct target cells, such as endothelial cells or leukocyte, and thereby deliver cellular components of their parental cells to the target cells. Hence, microparticles are a novel entity of circulating, paracrine, biological vectors which can influence the phenotype, the function and presumably even the transcriptome of their target cells.This review article aims to give a brief overview about the microparticle biology with a focus on endothelial activation and arterial hypertension. More detailed information about the role of microparticles in pathophysiology and disease can be found in already published work.
基金National Natural Science Foundation of China(51803190)National Key R&D Program of China(2019YFA0706802)for financial support。
文摘Ultra-thin flexible films have attracted wide attention because of their excellent ductility and potential versatility.In particular,the energy-harvesting films(EHFs)have become a research hotspot because of the indispensability of power source in various devices.However,the design and fabrication of such films that can capture or transform di erent types of energy from environments for multiple usages remains a challenge.Herein,the multifunctional flexible EHFs with e ective electro-/photo-thermal abilities are proposed by successive spraying Ag microparticles and MXene suspension between on waterborne polyurethane films,supplemented by a hot-pressing.The optimal coherent film exhibits a high electrical conductivity(1.17×10^(4)S m^(-1)),excellent Joule heating performance(121.3℃)at 2 V,and outstanding photo-thermal performance(66.2℃ within 70 s under 100 mW cm^(-1)).In addition,the EHFs-based single-electrode triboelectric nanogenerators(TENG)give short-circuit transferred charge of 38.9 nC,open circuit voltage of 114.7 V,and short circuit current of 0.82μA.More interestingly,the output voltage of TENG can be further increased via constructing the double triboelectrification layers.The comprehensive ability for harvesting various energies of the EHFs promises their potential to satisfy the corresponding requirements.
基金supported by the National Basic Research Program of China (973 Program,no. 2007CB714507)National Nature Science Foundation of China (no. 90813015)
文摘A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).
基金supported by the National Natural Science Foundation of China (40830743,40771187)the National Basic Research Program of China (2005CB422004)the State Key Laboratory of Gryospheric Sciences (SKLCS- ZZ-2008-01)
文摘The work presents microparticle concentrations in snowpits from the East Rongbuk Glacier on Mt. Qomolangma (Everest) (ER) (28.02°N, 86.96°E, 6536 m a.s.l.), the Zhadang Glacier on Mt. Nyainqentanglha (NQ) (30.47°N, 90.65°E, 5800m a.s.l.), and the Guoqu Glacier on Mt. Geladaindong (GL) (33.95°N, 91.28°E, 5823m a.s.l.) over the Tibetan Plateau (TP). Variations of microparticle and major ions (e.g. Mg2+, Ca2+) concentrations in snowpits show that the values of the microparticles and ions in the non-monsoon seasons are much higher than those in the monsoon seasons. Annual flux of microparticle deposition at ER is lower than those at NQ and GL, which could be attributed to the long distance away from the possible dust source regions as well as the elevation for ER higher than the others. Compared with other remote areas, microparticle concentrations in the southern TP are much lower than those in the northern TP, but still much higher than those in Greenland and Antarctica. The seasonal and spatial microparticle variations are clearly related to the variations of atmospheric circulation according to the air mass 5-day backward trajectory analyses of HYSPLIT Model. Resultingly, the high microparticle values in snow are mainly attributed to the westerlies and the strong dust storm outbreaks on the TP, while the monsoon circulation brings great amount of precipitation from the Indian Ocean, thus reducing in the aerosol concentrations.
文摘Supercritical antisolvent (SAS) process is a recently developed technology to produce micro- and nano particles. This paper presents a continuous apparatus to conduct experiment of SAS process. With the apparatus, the effects of pressure, temperature and flow ratio of CO2 to the solution on the shape and size of particles are studied for the quercetin-ethanol-CO2 system. Spherical quercetin microparticles with diameters ranging form 1 μm to 6μm can be obtained while ethanol is used as organic solvent. The most effective fact on the shape and size of particles is pressure, the next is temperature and the last is the flow ratio of CO2 to solution.
基金Supported by the National Natural Science Foundation of China （No.20536020, No.20476033）, the China Distinguished Young Scientist Fund （No.20225620） and Guangdong Province Science Fund （No.04020121）.
文摘An emulsion-congealing technique is used to prepare solid lipid microparticles （SLM） containing ibuprofen with glyceryl behenate, tripalmitin and beewax as excipients. The difference of the solubility parameters between the excipients and ibuprofen are used to analyze their compatibility. Both the solubility parameter analysis and the experimental results show that glyceryl behenate is the best among the three excipients. The solid particles disperse well in aqueous phase when the drug loading reaches 10% （relative to lipid only）. Glycerides exhibit marked polymorphism and their rapid rates of crystallization accelerate the formation of metastable crystal modification. The metastable crystal modification characterizes high drug loading capacity but less stability. Increasing the content of lipophilic drug in a lipid matrix facilitates the transformation of excipients to more stable polymorphic forms.
基金This work was supported by the General Research Fund scheme of the Hong Kong Research Grants Council(Project No.15227121)the Hong Kong Polytechnic University(ZVGH).
文摘Si is a promising anode material for Li ion batteries because of its high specific capacity,abundant reserve,and low cost.However,its rate performance and cycling stability are poor due to the severe particle pulverization during the lithiation/delithiation process.The high stress induced by the Li concentration gradient and anisotropic deformation is the main reason for the fracture of Si particles.Here we present a new stress mitigation strategy by uniformly distributing small amounts of Sn and Sb in Si micron-sized particles,which reduces the Li concentration gradient and realizes an isotropic lithiation/delithiation process.The Si8.5Sn0.5Sb microparticles(mean particle size:8.22μm)show over 6000-fold and tenfold improvements in electronic conductivity and Li diffusivity than Si particles,respectively.The discharge capacities of the Si_(8.5)Sn_(0.5)Sb microparticle anode after 100 cycles at 1.0 and 3.0 A g^(-1)are 1.62 and 1.19 Ah g^(-1),respectively,corresponding to a retention rate of 94.2%and 99.6%,respectively,relative to the capacity of the first cycle after activation.Multicomponent microparticle anodes containing Si,Sn,Sb,Ge and Ag prepared using the same method yields an ultra-low capacity decay rate of 0.02%per cycle for 1000 cycles at 1 A g^(-1),corroborating the proposed mechanism.The stress regulation mechanism enabled by the industry-compatible fabrication methods opens up enormous opportunities for low-cost and high-energy-density Li-ion batteries.
基金supported by the National Basic Research Program of China (No. 2010CB951003)Knowledge Innovation Programs of the Chinese Academy of Sciences (No. KZCX2-EW-311)+2 种基金the National Natural Science Foundation of China (Nos. 1141001040 and J0930003/J0109)the State Key Laboratory of Cryospheric Sciences Founding (No. SKLCS-ZZ-2010-04)the Program for New Century Excellent Talents in University from Ministry of Education of China (No. NCET-10-0019)
文摘ABSTRACT： Samples were continuously collected from aerosol, fresh snow, and snow pits on Glacier No. 1 at Urumqi River source in eastern Tianshan （天山） Mountains. The deposition processes and the characteristics of mineral dust microparticles from aerosol to fresh snow, and then evolution to the snow pit were determined. Total dust microparticle concentration in the surface snow and aerosol showed a similar temporal variation trend, which was strongly associated with regional and local at- mospheric circulation in the Tianshan Mountains region of Central Asia. Especially from November to February, the correlation coefficient of microparticles concentration in surface snow and aerosol is very high （R2=0.7）. Vertical profiles of microparticles in the snow pits showed that observed dust layers were in high correlation with concentration peaks of large microparticles （d〉10 μm）, but low correlation with that of fine microparticles （d〈1μm）. Moreover, explicit post-depositional process of dust particles was studied by tracking some typical dust concentration peaks in the snow pit. We find that late sum- mer is a key period for post-deposition of dust particles in the snow, as particle concentration peaks in the snow pit evolve intensely during this period. Such evolutional pattern of large particles makes it possible to preserve information of atmospheric dust in the snow, which offers an available proof to reconstruct historical climate using ice cores on Glacier No. 1 and other gla- ciers in the Tianshan Mountains.
文摘Ultrafine-grained(UFG)/nanocrystalline materials possess novel properties. Refining as-solidified grains of metals to the ultrafine and even nanometer scale by nanoparticles via slow cooling has been recently discovered. Here, we report that microparticles(CrB and CrB_(2)) with surface nanofeatures can also enable ultrafine/nano grains via slow cooling. CrB/CrB_(2) microparticles, formed by coalescence of nanoparticles in Cu matrix, display surface nanofeatures, which induce substantial grain refinement and stabilization down to the ultrafine/nano scale. The UFG Cu/Cr B and Cu/CrB_(2) samples exhibit exceptional thermal stability, comparable to UFG Cu induced by nanoparticles, without coarsening after annealing at 600°C for 1 h. The microhardness, strengths, and Young's moduli of the Cu/Cr B and Cu/CrB_(2) samples are significantly enhanced over pure Cu. This discovery has great potential to advance the mass production UFG/nanocrystalline for widespread applications.
基金Anhui Provincial Natural Science Foundation(No.08020303080) for financial support of this work
文摘A type of triangular pyramid-shaped microparticles of puerarin was synthesized by using oil-in-oil microemulsion approach which is simple and economical under the action of copper substrate.The pyramid-shaped microparticles would be made up of deposit of nanospheres or nanorods and have two significant characters.One is its complex surface morphology like coral reef.The other is a lot of nanopores in existence in the microparticle body.Two possible formation routes were speculated.
基金National Basic Research Program of China (2004CB217808)National Natural Science Foundation of China (20471041, 90306014)+1 种基金Natural Science Foundation of Shanxi Province (20051018)Shanxi Research Fund for Returned Scholars (200428)
文摘The deoiled asphalt as the carbon source and the ferrocene as the metal source and the catalyst precursor were chosen to synthesize iron-containing carbon microparticles through co-carbonization at the temperature of about 450℃ for 3 h. The resulting products were treated at 2 000 ℃ for 2 h. All samples were examined by high resolution transmission electron microscopy （HRTEM） and X-ray diffraction （XRD）. The results show that the iron particles in the heat-treated material are completely coated by carbon. In addition to the fully filled carbon microparticles as well as hollow carbon ones, also form carbon fibers with hollow centers. The formation mechanism of the as-prepared products was discussed briefly.
文摘AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascular disease,and 12 healthy controls were subjected to measurement of baseline platelet CD62 P, CD63 and CD42 b expression, platelet-leukocyte complexes, i.e., platelet-monocyte complexes(PMC), platelet-neutrophil complexes(PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles(PMPs) using flow cytometry. Both larger-size(0.5-0.9 μm) and smallersize(< 0.5 μm) PMPs were determined. Serum interleukin(IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index(PASI).RESULTS PMP concentrations were significantly higher in psoriasis patients than controls [mean±standard error of mean(SEM): 22±5/μL vs 11±6/μL; P=0.018), for both smaller-size(10±2/μL vs 4±2/μL; P=0.033) and larger-size(12±3/μL vs 6±4/μL; P=0.014) PMPs. Platelet CD62 P, CD63 and CD42 b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls(mean±SEM: 16%±3% vs 23%±6%; P=0.047). Larger-size PMPs were related with IL-12 levels(P<0.001) and smaller-size PMPs with both IL-12 and IL-17 levels(P<0.001). Total PMPs also correlated with IL-12(P<0.001). CD63 expression was positively correlated with both IL-12 and IL-17(P<0.05). Increased PASI score was associated with increased levels of larger-size PMPs(r=0.45; P=0.011) and increased CD63 expression(r=0.47; P<0.01).CONCLUSION PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.
文摘Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.
文摘In current work,Ni-Ti-CeO_(2) nanocomposite coatings were achieved by co-adding Ti microparticles and CeO_(2) nanoparticles.Designed experiments and COMSOL computer simulation were applied to reveal the synergistic role of Ti microparticles and CeO_(2) nanoparticles in tailoring the spatial microstructures and properties of Ni-Ti-CeO_(2) nanocomposite coating.Unilaterally,the conductive Ti microparticles conducted the growth behavior of Ni grains by current density concentration,distorting electronic feld lines and heterogeneous nucleation.Individual domains consisting of inner nanograins and outer radial columnar grains surrounded Ti microparticles,where Ti microparticles acted as seeds.Ti microparticles tended to be aggregated,leading to spatial heterogeneity of microstructures.Ni deposits buried the Ti microparticles in forms of“covering model”,contributing to the formation of inside voids and rough surface and aggregation of Ti microparticles;on the other hand,the non-conductive CeO_(2)microparticles hardly changed the distribution of current density and electronic feld lines on the cathode surface.Ni deposits buried the CeO_(2)microparticle in forms of“stacking model”,avoiding the inside voids and aggregation of particles.The incorporation of CeO_(2)microparticle brought in microstructure evolutions only on its top side without disturbing the growth behavior of Ni grains on its lateral side or bottom,suggesting the limited effects.This was correlated with the presence of current concentration above the CeO_(2) microparticle at the last stage of burying CeO_(2) microparticle.The co-addition of Ti microparticles and CeO_(2) nanoparticles into Ni deposits exploited the complementary action of the two particles,which gave birth to satisfed spatial microstructures and improved hardness.Ti microparticles took major responsibility for microstructure evolutions,while the CeO_(2) nanoparticles were mainly in charge of the microstructure homogeneity.
基金the Danish Council for Inde-pendent Research(Grant No.DFF-12-131927)for financial sup-port of this project
文摘Hypromellose acetate succinate(HPMCAS) microparticles containing the poorly-water soluble drug celecoxib(CEL) were prepared by electrospraying intended for oral drug delivery. Various solvent mixtures with different solubility for CEL and HPMCAS were used to induce changes in the polymer structural conformation of the microparticles. The performance of the prepared microparticles was evaluated by studying the solid state from, particle size and morphology, radial drug distribution and drug release. CEL was amorphous in all electrosprayed HPMCAS microparticles. The particle size and morphology was dependent on the solubility of HPMCAS in the solvent mixture used with poorer solvents resulting in smaller microparticles with rougher appearance. The CEL distribution on the particles surface was relatively homogeneous and similar for all microparticles. Drug release from the microparticles was observed at a higher rate depending on the solubility of HPMCAS in the solvent used for electrospraying, and in all cases an at least 4-fold higher rate was observed compared with the crystalline drug. Drug precipitation from the supersaturated solution was inhibited by HPMCAS for all microparticles based on its parachute effect while crystalline CEL did not reach supersaturation. This study demonstrated that electrospraying can be used to produce microparticles with tailored properties for pharmaceutical application by adjusting solvent selection.
