On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation f...On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation frequently shifts during the measurement process.Consequently,a substantial amount of time is allocated to calibrating pre-travel error and probe movement.Furthermore,the frequent movement of machine tools also increases the influence of machine errors.To enhance both accuracy and efficiency,an optimization strategy for the OMM process is proposed.Based on the kinematic chain of the machine tools,the relationship between the angle combination of rotary axes,the stylus orientation,and the calibration position of pre-travel error is disclosed.Additionally,an OMM efficiency optimization model for complex curved surfaces is developed.This model is solved to produce the optimal efficiency angle combinations for each to-be-measured point.Within each angle combination,the effects of positioning errors on measurement results are addressed by coordinate system offset and measurement result compensation method.Finally,the experiments on an impeller are used to demonstrate the practical utility of the proposed method.展开更多
Dear Editor,We present a case of acute zonal occult outer retinopathy(AZOOR)complex in a myopic patient with angioid streaks(ASs).A 19-year-old female has been experiencing visual field defects in her left eye for mor...Dear Editor,We present a case of acute zonal occult outer retinopathy(AZOOR)complex in a myopic patient with angioid streaks(ASs).A 19-year-old female has been experiencing visual field defects in her left eye for more than 3y.She was diagnosed with ASs and choroiditis at a local hospital.She has a seven-year history of bilateral high myopia.A fundus examination confirmed the presence of ASs and myopic fundus changes in both eyes.Multimodal imaging revealed an AZOOR complex in the left eye.展开更多
Complex trimalleolar ankle fractures are a major orthopaedic challenge,with an incidence of 4.22 per 10000 person-years in the United States and an annual cost of 3.4 billion dollars.This review synthesizes current ev...Complex trimalleolar ankle fractures are a major orthopaedic challenge,with an incidence of 4.22 per 10000 person-years in the United States and an annual cost of 3.4 billion dollars.This review synthesizes current evidence on diagnostic protocols and management strategies,highlighting optimal approaches and emerging trends.Initial care emphasizes soft tissue assessment,often guided by the Tscherne classification,and fracture classification systems.External fixation may be required in open injuries,while early open reduction and internal fixation within six days is linked to improved outcomes.Minimally invasive techniques for the lateral malleolus,including intramedullary nailing and locking plates,are effective,while medial malleolus fractures are commonly managed with screw fixation or tension-band wiring.Posterior malleolus fragments involving more than 25%of the articular surface usually warrant fixation.Alternatives to syndesmotic screws,such as cortical buttons or high-strength sutures,reduce the need for secondary procedures.Arthroscopic-assisted open reduction and internal fixation benefits younger,active patients by enabling concurrent management of intra-articular and ligamentous injuries.Postoperative care prioritizes early weight-bearing and validated functional scores.Despite advances,complications remain common,and further research is needed to refine surgical strategies and improve outcomes.展开更多
Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to...Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.展开更多
In our previous study,a novel organic selenium compound Eb was synthesized and found to have significant antitumor activity with much less toxicity compared with the leading compound Ebselen.Unfortunately,Eb was pract...In our previous study,a novel organic selenium compound Eb was synthesized and found to have significant antitumor activity with much less toxicity compared with the leading compound Ebselen.Unfortunately,Eb was practically insoluble in water （2.57 μg/mL） and had very low oral bioavailability,thus its clinical application was greatly limited.In the present study,the inclusion complex of Eb with 2-hydroxypropyl-β-cyclodextrin （HP-βCD） was prepared and pharmacokinetics of Eb and the inclusion complex were investigated.The water solubility of Eb was dramatically enhanced by inclusion with HP-βCD,which reached 8.4 mg/mL.The pharmacokinetic study showed that the elimination half-life （t 1/2β） of Eb was between 22 h and 30 h and the distribution half-life （t 1/2α） of Eb was 1 h.The results indicated that Eb was rapidly distributed to tissues but slowly eliminated in rats.The absolute bioavailability of Eb/HP-βCD inclusion complex solution through the oral route was 28.3%,and it was 1552% that of Eb in its pure form.In summary,the absorption of Eb in the Eb/HP-βCD inclusion complex was better and faster than that of Eb in its pure form.展开更多
针对无线和电力线通信混合组网的信道竞争接入问题,提出了一种基于深度强化学习的电力线与无线双模通信的MAC接入算法。双模节点根据网络广播信息和信道使用等数据自适应接入双媒质信道。首先建立了基于双模通信网络交互和统计信息的双...针对无线和电力线通信混合组网的信道竞争接入问题,提出了一种基于深度强化学习的电力线与无线双模通信的MAC接入算法。双模节点根据网络广播信息和信道使用等数据自适应接入双媒质信道。首先建立了基于双模通信网络交互和统计信息的双模通信节点数据采集模型;接着定义了基于协作信息的深度强化学习(deep reinforcement learning,DRL)状态空间、动作空间和奖励,设计了联合α-公平效用函数和P坚持接入机制的节点决策流程,实现基于双深度Q网络(double deep Q-network,DDQN)的双模节点自适应接入算法;最后进行算法性能仿真和对比分析。仿真结果表明,提出的接入算法能够在保证双模网络和信道接入公平性的条件下,有效提高双模通信节点的接入性能。展开更多
Cationic polyethylenimine （PEI） with dextran fluorescein anionic （DFA） or oligodeoxynucleotide （ODN） could form polyelectrolyte complex by self-assembly as a gene delivery vector. This study was designed to inve...Cationic polyethylenimine （PEI） with dextran fluorescein anionic （DFA） or oligodeoxynucleotide （ODN） could form polyelectrolyte complex by self-assembly as a gene delivery vector. This study was designed to investigate the effects on pharmaceutical characteristics and cell uptake PEI after a long-circulation modification with poly（ethylene glycol） （PEG）. DFA or ODN reacted with PEI or PEI-PEG to form polyelectrolyte complexes. Surface characters of these complexes and the retardation of ODN by PEI and PEI-PEG were evaluated. The uptake rates of DFA/PEI and DFA/PEI-PEG complexes by MCF-7 cells were evaluated by flow cytometry. Confocal laser scanning microscopy was utilized to visualize the internalization of these complexes. ODN/PEI complex showed the dependence of their size and ξ potential on the N/P ratio. ODN/PEI-PEG complex were much less affected by N/P ratio and their size was around 30 100 nm. PEI and PEI-PEG retarded ODN even at N/P ratio as low as 4, and complete retardation was found at N/P ratio of 8. The uptake rate by MCF-7 cells was direct correlated to the DFA concentration and incubation time, and the uptake rate could exceed 99% under the selected condition. The results in this study showed that PEI self-assembly polyelectrolyte complex after stealth or long circulation modification may increase the ability as a gene vector to delivery genes into cells.展开更多
Objective The aim of this study was to investigate macular perfusion changes and ganglion cell complex(GCC)loss in patients with unexplained visual loss following vitrectomy and silicone oil(SO)tamponade,and to evalua...Objective The aim of this study was to investigate macular perfusion changes and ganglion cell complex(GCC)loss in patients with unexplained visual loss following vitrectomy and silicone oil(SO)tamponade,and to evaluate the correlation between retinal blood flow and GCC loss using optical coherence tomography angiography(OCTA)and optical coherence tomography(OCT).Methods This retrospective study included seven eyes(seven patients)with unexpected visual loss after vitrectomy and SO tamponade.OCTA was used to evaluate the alterations in retinal vessel density(VD)in the superficial capillary plexus(SCP),deep capillary plexus(DCP),and radial peripapillary capillary plexus(RPCP).OCT was used to measure the thickness of GCC and retinal nerve fiber layer(RNFL).Medical records of patients were reviewed.Results Quantitative analysis of OCTA images revealed a significant reduction in SCP VD in the affected eyes compared with the controls(all sections P<0.05).No difference was found in GCC thickness,but FLV(focal loss volume)and GLV(global loss volume)were significantly higher in the affected eyes(both P<0.001).SCP VD was inversely correlated with FLV and GLV.Conclusions Silicone oil-related severe visual loss was associated with superficial retinal microvasculature damage and ganglion cell apoptosis.展开更多
Two novel heterometallic trinuclear complexes of macrocyclic oxamide [Mn（NiL）2（HBTC）H2O] （1） and [Zn（NiL）2（HBTC）H2O] （2） （NiL, H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien,...Two novel heterometallic trinuclear complexes of macrocyclic oxamide [Mn（NiL）2（HBTC）H2O] （1） and [Zn（NiL）2（HBTC）H2O] （2） （NiL, H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H3BTC = 1,3,5-benzenetricarboxylic acid） have been solvothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. For 1, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.3595（5）, b = 23.1498（11）, c = 17.2558（8） and =101.2530（10）°. For 2, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.5214（8）, b = 20.6566（14）, c = 18.4126（13） and = 92.6770（10）°. The structures of 1 and 2 have oxamido-bridged trinuclear [NiⅡ2MⅡ] units and consist of two-dimensional supramolecular architectures formed by strong O–H…O intermolecular hydrogen bonds.展开更多
3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and ...3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and the technology has found widespread industrial applications for production from automotive parts to machine tools,its application in pharmaceutical area is still limited. However,the potential of 3 D printing in the pharmaceutical industry is now being recognized. The ability of 3 D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes,sizes and textures that are difficult to produce using traditional techniques. However,there are various challenges associated with the proper application of3 D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review,an overview is provided on the various 3 D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.展开更多
The very latest technique for impeller manufacture is called semi-solid moulding(SSM).Cummins Turbo Technologies Limited,together with Aluminum Complex Components Inc,developed SSM compressor wheels as a way of achiev...The very latest technique for impeller manufacture is called semi-solid moulding(SSM).Cummins Turbo Technologies Limited,together with Aluminum Complex Components Inc,developed SSM compressor wheels as a way of achieving cost and durability performance somewhere between that of cast and machined from solid(MFS) aluminium alloy wheels.Experimental results show SSM material has a superior microstructure and mechanical properties over cast and comparable to MFS materials.Component testing including durability testing,using accelerated speed cycle tests,proves SSM compressor wheels emerge as being significantly more durable than cast equivalents and approaching that of MFS impellers.Further challenges for semi-solid processing in manufacture of other complex components and other materials in automotive industry in terms of both cost and durability are also discussed.展开更多
A robust voltammetric method has been developed and validated for the determination of Fe（Ⅱ） and Fe（Ⅲ） in pharmaceutical iron polysaccharidic complexes. Undesirable low molecular weight iron complexes, at concen...A robust voltammetric method has been developed and validated for the determination of Fe（Ⅱ） and Fe（Ⅲ） in pharmaceutical iron polysaccharidic complexes. Undesirable low molecular weight iron complexes, at concentration about 3% in the pharmaceutical formulation, can be easily determined with good accuracy and precision. This methodology can be proposed as a viable, environmentally sustainable substitute for the conventional Normal Pulse Polarographic method in US Pharmacopeia, with better analytical figures of merit, and reduced Hg consumption. A deeper insight in Fe（Ⅱ） and Fe（Ⅲ） composition can be gained by the combined use of a new potentiometric technique after chemical decomposition of the complex.展开更多
An optimized and validated spectrophotometric method has been developed for the determination of cefixime in pharmaceutical formulations. The method is based on the complexa- tion reaction between cefixime and palladi...An optimized and validated spectrophotometric method has been developed for the determination of cefixime in pharmaceutical formulations. The method is based on the complexa- tion reaction between cefixime and palladium ion in the presence of acidic buffer solution （pH 3） in ethanol-distilled water medium at room temperature. The complex absorbed maximally at 352 nm. Beer＇s law is obeyed in the working concentration range of 2.5-35 μg/mL with apparent molar absorptivity of 1.015×104 L/mol cm and Sandell＇s sensitivity of 0.001 μg/cm2/0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.175 and 0.583μg/mL, respectively. The effect of common excipients used as additives has been studied in the determination of cefixime. The proposed method has been successfully applied for the determina- tion of cefixime in pharmaceutical formulations. The results obtained by the proposed method were statistically compared with the reference method using t and F values and found no significant difference between the two methods.展开更多
The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated i...The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper. The results showed that the highest activity in hydrolysis of BNPP was obtained with le--Zn（II） complex （composed of lipophilic group） as catalyst. The hydrolysis rate enhancement is up to 3.64 × 10^4 fold. These metal complexes could effectively promote the cleavage of plasmid DNA （pUC18） at physiological conditions.展开更多
A novel complex [Cd2（phen）4（phth）2]·4H2O has been synthesized by the reaction of Hzphth（phthalic acid） and phen（1,10-phenanthroline） with Cd（Ⅱ） in ethanol-water solution. X-ray crystal structure analys...A novel complex [Cd2（phen）4（phth）2]·4H2O has been synthesized by the reaction of Hzphth（phthalic acid） and phen（1,10-phenanthroline） with Cd（Ⅱ） in ethanol-water solution. X-ray crystal structure analysis shows it crystallizes in triclinic, space group PI- with a = 10.619（3）, b = 12.560（4）, c = 12.651（4） A, a = 98.775（5）, β = 109.035（5）,γ = 113-576（5）°, C32H24CdN4O6, Mr= 672.95, V = 1381.7（7）A^3, Rint = 0.0358, Z = 2, Dc= 1.618 g/cm^3,μ = 0.845 mm^-1, -6 ≤h≤13, -15 ≤k ≤13, -15 ≤l≤14, F（000） = 680, S = 1.038, R = 0.0480 and wR = 0.0849 for 3992 observed reflections （1 〉 2σ（Ⅰ））. Phth bridges Cd（Ⅱ） to form a macrocyclic compound, and a 2D supramolecular motif is formed through hydrogen bonds and π-π interaction.展开更多
The paper presents the results of the synthesis of complexes of the ty pe Eu(DBM) 3 and Eu(DBM) 3·Q(DBM-dibenzoylmethane,Q-1,10-phenantroline or 4,7-d iphenyl-1,10-phenantroline) and of Tb-and Nd-complexes with t...The paper presents the results of the synthesis of complexes of the ty pe Eu(DBM) 3 and Eu(DBM) 3·Q(DBM-dibenzoylmethane,Q-1,10-phenantroline or 4,7-d iphenyl-1,10-phenantroline) and of Tb-and Nd-complexes with the newly-synthesis ed coumarin derivates 3,3’-[(4-chlorphenyl) methylene) bis(4-hydroxy-2H-chromen-2-one) ,3,3’-[(3,5-dimethoxy-4-hydroxy) methylene) bis(4-hydroxy-2H-chromen-2-one) ,etc. Elemental and thermogravimetric analysis,IR,UV,NMR and fluorescence spe ctroscopy and X-ray analysis were applied for characterisation of the complexes. Some peculiarities of the synthetic procedures for both types of complexes were discussed and the influence of the synthetic approach,pH of the reaction mediu m,temperature of synthesis and drying of the complexes on the composition,stab ility and optical properties was reported. The immobilisation of the complexes i n thin films based on sol-gel produced SiO2 and on polymethylmethacrylate was st udied. The optimal conditions for preparation of the matrices(composition of th e starting system,temperature and time of sol aging,etc.) were recommended. Th e film morphology was evaluated by fluorescence,scanning electron and atomic fo rce microscopy. The interaction of the lanthanide ions with the matrices and the influence of their nature,the effect of the in-situ polymerisation and other f actors on photoluminescent excitation and emission spectra and excited state lif e-times of the complexes were followed. The effect of the second ligand on the p hotoluminescence properties of the immobilised diketonates was further elucidate d. Processes involved in the thermal decomposition of the complexes and microcom posites produced on their base were proposed. Preliminary results on the pharmac ological properties of the coumarin complexes reported showed unambiguously high er cytotoxicity of the Nd complex in comparison with that of the respective ligand.展开更多
Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [Z...Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [ZnL]（ClO4）2 with NH4VO3 and K2[Ni（CN）4], respectively, and structurally characterized by elemental analysis, IR, XRPD, TG and X-ray diffraction. Single-crystal X-ray diffraction analyses indicated that the Zn（Ⅱ） atom lies on an inversion center and is octahedrally coordinated by four nitrogen atoms of the tetradentate macrocyclic ligand in the equatorial plane and two oxygen atoms of [VO4] tetrahedra in the axial positions in 1, and two oxygen atoms of two water molecules in 2. Complex 1 shows a three-dimensional structure, which is constructed by the links of [VO3]nn- chains with [ZnL]2＋, forming one-dimensional channels occupied by vip water molecules. The monomers of [ZnL（H2O）2]2＋ and [Ni（CN）4]2- are connected through the intermolecular hydrogen bonds to form a two-dimensional sheet in complex 2.展开更多
基金Projects(51775445,52175435)supported by the National Natural Science Foundation of ChinaProject(CX2023051)supported by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China。
文摘On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation frequently shifts during the measurement process.Consequently,a substantial amount of time is allocated to calibrating pre-travel error and probe movement.Furthermore,the frequent movement of machine tools also increases the influence of machine errors.To enhance both accuracy and efficiency,an optimization strategy for the OMM process is proposed.Based on the kinematic chain of the machine tools,the relationship between the angle combination of rotary axes,the stylus orientation,and the calibration position of pre-travel error is disclosed.Additionally,an OMM efficiency optimization model for complex curved surfaces is developed.This model is solved to produce the optimal efficiency angle combinations for each to-be-measured point.Within each angle combination,the effects of positioning errors on measurement results are addressed by coordinate system offset and measurement result compensation method.Finally,the experiments on an impeller are used to demonstrate the practical utility of the proposed method.
基金Supported by the National Natural Science Foundation of China(No.82171073).
文摘Dear Editor,We present a case of acute zonal occult outer retinopathy(AZOOR)complex in a myopic patient with angioid streaks(ASs).A 19-year-old female has been experiencing visual field defects in her left eye for more than 3y.She was diagnosed with ASs and choroiditis at a local hospital.She has a seven-year history of bilateral high myopia.A fundus examination confirmed the presence of ASs and myopic fundus changes in both eyes.Multimodal imaging revealed an AZOOR complex in the left eye.
文摘Complex trimalleolar ankle fractures are a major orthopaedic challenge,with an incidence of 4.22 per 10000 person-years in the United States and an annual cost of 3.4 billion dollars.This review synthesizes current evidence on diagnostic protocols and management strategies,highlighting optimal approaches and emerging trends.Initial care emphasizes soft tissue assessment,often guided by the Tscherne classification,and fracture classification systems.External fixation may be required in open injuries,while early open reduction and internal fixation within six days is linked to improved outcomes.Minimally invasive techniques for the lateral malleolus,including intramedullary nailing and locking plates,are effective,while medial malleolus fractures are commonly managed with screw fixation or tension-band wiring.Posterior malleolus fragments involving more than 25%of the articular surface usually warrant fixation.Alternatives to syndesmotic screws,such as cortical buttons or high-strength sutures,reduce the need for secondary procedures.Arthroscopic-assisted open reduction and internal fixation benefits younger,active patients by enabling concurrent management of intra-articular and ligamentous injuries.Postoperative care prioritizes early weight-bearing and validated functional scores.Despite advances,complications remain common,and further research is needed to refine surgical strategies and improve outcomes.
基金National Natural Science Foundation of China (50635040)National High-tech Research and Development Program (2009AA04Z302)Jiangsu Provincial Natural Science Foundation (BK2008043)
文摘Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.
基金Natural Science Foundation of Beijing (Grant No. 7021001)the Foundation for the Special Program of the Following Novel Candidate Drug by Beijing S&T Committee (Grant No. H20220060190)National Natural Science Foundation (Grant No.30472036)
文摘In our previous study,a novel organic selenium compound Eb was synthesized and found to have significant antitumor activity with much less toxicity compared with the leading compound Ebselen.Unfortunately,Eb was practically insoluble in water （2.57 μg/mL） and had very low oral bioavailability,thus its clinical application was greatly limited.In the present study,the inclusion complex of Eb with 2-hydroxypropyl-β-cyclodextrin （HP-βCD） was prepared and pharmacokinetics of Eb and the inclusion complex were investigated.The water solubility of Eb was dramatically enhanced by inclusion with HP-βCD,which reached 8.4 mg/mL.The pharmacokinetic study showed that the elimination half-life （t 1/2β） of Eb was between 22 h and 30 h and the distribution half-life （t 1/2α） of Eb was 1 h.The results indicated that Eb was rapidly distributed to tissues but slowly eliminated in rats.The absolute bioavailability of Eb/HP-βCD inclusion complex solution through the oral route was 28.3%,and it was 1552% that of Eb in its pure form.In summary,the absorption of Eb in the Eb/HP-βCD inclusion complex was better and faster than that of Eb in its pure form.
文摘针对无线和电力线通信混合组网的信道竞争接入问题,提出了一种基于深度强化学习的电力线与无线双模通信的MAC接入算法。双模节点根据网络广播信息和信道使用等数据自适应接入双媒质信道。首先建立了基于双模通信网络交互和统计信息的双模通信节点数据采集模型;接着定义了基于协作信息的深度强化学习(deep reinforcement learning,DRL)状态空间、动作空间和奖励,设计了联合α-公平效用函数和P坚持接入机制的节点决策流程,实现基于双深度Q网络(double deep Q-network,DDQN)的双模节点自适应接入算法;最后进行算法性能仿真和对比分析。仿真结果表明,提出的接入算法能够在保证双模网络和信道接入公平性的条件下,有效提高双模通信节点的接入性能。
基金National Nature Science Foundation of China (Grant No.30772665)Beijing Nature Science Foundation (Grant No.7083111).
文摘Cationic polyethylenimine （PEI） with dextran fluorescein anionic （DFA） or oligodeoxynucleotide （ODN） could form polyelectrolyte complex by self-assembly as a gene delivery vector. This study was designed to investigate the effects on pharmaceutical characteristics and cell uptake PEI after a long-circulation modification with poly（ethylene glycol） （PEG）. DFA or ODN reacted with PEI or PEI-PEG to form polyelectrolyte complexes. Surface characters of these complexes and the retardation of ODN by PEI and PEI-PEG were evaluated. The uptake rates of DFA/PEI and DFA/PEI-PEG complexes by MCF-7 cells were evaluated by flow cytometry. Confocal laser scanning microscopy was utilized to visualize the internalization of these complexes. ODN/PEI complex showed the dependence of their size and ξ potential on the N/P ratio. ODN/PEI-PEG complex were much less affected by N/P ratio and their size was around 30 100 nm. PEI and PEI-PEG retarded ODN even at N/P ratio as low as 4, and complete retardation was found at N/P ratio of 8. The uptake rate by MCF-7 cells was direct correlated to the DFA concentration and incubation time, and the uptake rate could exceed 99% under the selected condition. The results in this study showed that PEI self-assembly polyelectrolyte complex after stealth or long circulation modification may increase the ability as a gene vector to delivery genes into cells.
基金supported by Capital Medical University Affiliated Beijing Tongren Hospital Key Medical Development Plan[trzdyxzy201801].
文摘Objective The aim of this study was to investigate macular perfusion changes and ganglion cell complex(GCC)loss in patients with unexplained visual loss following vitrectomy and silicone oil(SO)tamponade,and to evaluate the correlation between retinal blood flow and GCC loss using optical coherence tomography angiography(OCTA)and optical coherence tomography(OCT).Methods This retrospective study included seven eyes(seven patients)with unexpected visual loss after vitrectomy and SO tamponade.OCTA was used to evaluate the alterations in retinal vessel density(VD)in the superficial capillary plexus(SCP),deep capillary plexus(DCP),and radial peripapillary capillary plexus(RPCP).OCT was used to measure the thickness of GCC and retinal nerve fiber layer(RNFL).Medical records of patients were reviewed.Results Quantitative analysis of OCTA images revealed a significant reduction in SCP VD in the affected eyes compared with the controls(all sections P<0.05).No difference was found in GCC thickness,but FLV(focal loss volume)and GLV(global loss volume)were significantly higher in the affected eyes(both P<0.001).SCP VD was inversely correlated with FLV and GLV.Conclusions Silicone oil-related severe visual loss was associated with superficial retinal microvasculature damage and ganglion cell apoptosis.
基金supported by the National Natural Science Foundation of China(No.20771083)
文摘Two novel heterometallic trinuclear complexes of macrocyclic oxamide [Mn（NiL）2（HBTC）H2O] （1） and [Zn（NiL）2（HBTC）H2O] （2） （NiL, H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H3BTC = 1,3,5-benzenetricarboxylic acid） have been solvothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. For 1, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.3595（5）, b = 23.1498（11）, c = 17.2558（8） and =101.2530（10）°. For 2, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.5214（8）, b = 20.6566（14）, c = 18.4126（13） and = 92.6770（10）°. The structures of 1 and 2 have oxamido-bridged trinuclear [NiⅡ2MⅡ] units and consist of two-dimensional supramolecular architectures formed by strong O–H…O intermolecular hydrogen bonds.
基金supported by Keimyung University Research Grant of 2017
文摘3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and the technology has found widespread industrial applications for production from automotive parts to machine tools,its application in pharmaceutical area is still limited. However,the potential of 3 D printing in the pharmaceutical industry is now being recognized. The ability of 3 D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes,sizes and textures that are difficult to produce using traditional techniques. However,there are various challenges associated with the proper application of3 D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review,an overview is provided on the various 3 D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.
文摘The very latest technique for impeller manufacture is called semi-solid moulding(SSM).Cummins Turbo Technologies Limited,together with Aluminum Complex Components Inc,developed SSM compressor wheels as a way of achieving cost and durability performance somewhere between that of cast and machined from solid(MFS) aluminium alloy wheels.Experimental results show SSM material has a superior microstructure and mechanical properties over cast and comparable to MFS materials.Component testing including durability testing,using accelerated speed cycle tests,proves SSM compressor wheels emerge as being significantly more durable than cast equivalents and approaching that of MFS impellers.Further challenges for semi-solid processing in manufacture of other complex components and other materials in automotive industry in terms of both cost and durability are also discussed.
基金supported by FAR, Fondo Ateneoper la Ricerca Universitá di Pavia,Italy
文摘A robust voltammetric method has been developed and validated for the determination of Fe（Ⅱ） and Fe（Ⅲ） in pharmaceutical iron polysaccharidic complexes. Undesirable low molecular weight iron complexes, at concentration about 3% in the pharmaceutical formulation, can be easily determined with good accuracy and precision. This methodology can be proposed as a viable, environmentally sustainable substitute for the conventional Normal Pulse Polarographic method in US Pharmacopeia, with better analytical figures of merit, and reduced Hg consumption. A deeper insight in Fe（Ⅱ） and Fe（Ⅲ） composition can be gained by the combined use of a new potentiometric technique after chemical decomposition of the complex.
文摘An optimized and validated spectrophotometric method has been developed for the determination of cefixime in pharmaceutical formulations. The method is based on the complexa- tion reaction between cefixime and palladium ion in the presence of acidic buffer solution （pH 3） in ethanol-distilled water medium at room temperature. The complex absorbed maximally at 352 nm. Beer＇s law is obeyed in the working concentration range of 2.5-35 μg/mL with apparent molar absorptivity of 1.015×104 L/mol cm and Sandell＇s sensitivity of 0.001 μg/cm2/0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.175 and 0.583μg/mL, respectively. The effect of common excipients used as additives has been studied in the determination of cefixime. The proposed method has been successfully applied for the determina- tion of cefixime in pharmaceutical formulations. The results obtained by the proposed method were statistically compared with the reference method using t and F values and found no significant difference between the two methods.
基金supported by the Science and Technology Department(No.04JY029-018)Education Department of Sichuan Province(No.2006ZD049).
文摘The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper. The results showed that the highest activity in hydrolysis of BNPP was obtained with le--Zn（II） complex （composed of lipophilic group） as catalyst. The hydrolysis rate enhancement is up to 3.64 × 10^4 fold. These metal complexes could effectively promote the cleavage of plasmid DNA （pUC18） at physiological conditions.
基金The project was supported by the NSF of Liaoning Province (No. 20022018)
文摘A novel complex [Cd2（phen）4（phth）2]·4H2O has been synthesized by the reaction of Hzphth（phthalic acid） and phen（1,10-phenanthroline） with Cd（Ⅱ） in ethanol-water solution. X-ray crystal structure analysis shows it crystallizes in triclinic, space group PI- with a = 10.619（3）, b = 12.560（4）, c = 12.651（4） A, a = 98.775（5）, β = 109.035（5）,γ = 113-576（5）°, C32H24CdN4O6, Mr= 672.95, V = 1381.7（7）A^3, Rint = 0.0358, Z = 2, Dc= 1.618 g/cm^3,μ = 0.845 mm^-1, -6 ≤h≤13, -15 ≤k ≤13, -15 ≤l≤14, F（000） = 680, S = 1.038, R = 0.0480 and wR = 0.0849 for 3992 observed reflections （1 〉 2σ（Ⅰ））. Phth bridges Cd（Ⅱ） to form a macrocyclic compound, and a 2D supramolecular motif is formed through hydrogen bonds and π-π interaction.
基金Project supported by the Bulgarian Fund for Scientific Investigations (VUH 005/05 and DO 02-129/08)
文摘The paper presents the results of the synthesis of complexes of the ty pe Eu(DBM) 3 and Eu(DBM) 3·Q(DBM-dibenzoylmethane,Q-1,10-phenantroline or 4,7-d iphenyl-1,10-phenantroline) and of Tb-and Nd-complexes with the newly-synthesis ed coumarin derivates 3,3’-[(4-chlorphenyl) methylene) bis(4-hydroxy-2H-chromen-2-one) ,3,3’-[(3,5-dimethoxy-4-hydroxy) methylene) bis(4-hydroxy-2H-chromen-2-one) ,etc. Elemental and thermogravimetric analysis,IR,UV,NMR and fluorescence spe ctroscopy and X-ray analysis were applied for characterisation of the complexes. Some peculiarities of the synthetic procedures for both types of complexes were discussed and the influence of the synthetic approach,pH of the reaction mediu m,temperature of synthesis and drying of the complexes on the composition,stab ility and optical properties was reported. The immobilisation of the complexes i n thin films based on sol-gel produced SiO2 and on polymethylmethacrylate was st udied. The optimal conditions for preparation of the matrices(composition of th e starting system,temperature and time of sol aging,etc.) were recommended. Th e film morphology was evaluated by fluorescence,scanning electron and atomic fo rce microscopy. The interaction of the lanthanide ions with the matrices and the influence of their nature,the effect of the in-situ polymerisation and other f actors on photoluminescent excitation and emission spectra and excited state lif e-times of the complexes were followed. The effect of the second ligand on the p hotoluminescence properties of the immobilised diketonates was further elucidate d. Processes involved in the thermal decomposition of the complexes and microcom posites produced on their base were proposed. Preliminary results on the pharmac ological properties of the coumarin complexes reported showed unambiguously high er cytotoxicity of the Nd complex in comparison with that of the respective ligand.
基金supported by the Project for Undergraduate Research Study and Innovative Experiment of Hunan Provincial(2013-191)National Undergraduate Training Programs for Innovation and Entrepreneurship(201310551158)+4 种基金the Scientific Research Fund of Hunan Provincial Education Department(13B029,13A030)the Key Laboratory of Functional Organometallic Materials of Hunan Province College(13K09,13K10)the Program for Excellent Talents in Hunan University of Science and Engineeringthe Construct Program of the Key Discipline in Hunan Province(2011-76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2012-318)
文摘Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [ZnL]（ClO4）2 with NH4VO3 and K2[Ni（CN）4], respectively, and structurally characterized by elemental analysis, IR, XRPD, TG and X-ray diffraction. Single-crystal X-ray diffraction analyses indicated that the Zn（Ⅱ） atom lies on an inversion center and is octahedrally coordinated by four nitrogen atoms of the tetradentate macrocyclic ligand in the equatorial plane and two oxygen atoms of [VO4] tetrahedra in the axial positions in 1, and two oxygen atoms of two water molecules in 2. Complex 1 shows a three-dimensional structure, which is constructed by the links of [VO3]nn- chains with [ZnL]2＋, forming one-dimensional channels occupied by vip water molecules. The monomers of [ZnL（H2O）2]2＋ and [Ni（CN）4]2- are connected through the intermolecular hydrogen bonds to form a two-dimensional sheet in complex 2.
