Objective: To evaluate the sedative effect of Diospyros lotus L(D. lotus) extract in mice using the open field and Rota rod tests.Methods: For the sedative and muscle relaxants activities of extract/fractions of the p...Objective: To evaluate the sedative effect of Diospyros lotus L(D. lotus) extract in mice using the open field and Rota rod tests.Methods: For the sedative and muscle relaxants activities of extract/fractions of the plant, invivo open field and phenobarbitone-induced sleeping time were used, while the Roda rod test was employed in animals for the assessment of muscle relaxant activity.Results: Results from this investigation revealed that the extracts of D. lotus have exhibited significant sedative effect in mice(45.98%) at 100 mg/kg i.p. When the extract was partitioned with different solvents, the n-hexane fraction was inactive whereas the chloroform fraction was the most active with 82.67% sedative effect at 50 and 100 mg/kg i.p. On the other hand,the ethyl acetate and n-butanol fractions displayed significant sedative effects(55.65% and40.87%, respectively) at 100 mg/kg i.p. Among the tested extract/fractions, only chloroform and ethyl acetate fractions showed significant(P < 0.05) muscle relaxant activity in the Rota rod test.Conclusions: In short, our study provided scientific background to the traditional uses of D.lotus as sedative.展开更多
Increasing epidemiological evidence supports the view, that quercetin has protective roles in a multitude of disease states in human who have a high intake of polyphenols. To investigate the ability of quercetin and i...Increasing epidemiological evidence supports the view, that quercetin has protective roles in a multitude of disease states in human who have a high intake of polyphenols. To investigate the ability of quercetin and its rutinoside, rutin, to modulate the relaxation of human airways smooth muscle and to determine the mechanism (s) of such relaxation, isolated human bronchus rings were suspended in individual organ baths, precontracted with acetylcholine or with histamine and the relaxing effects of quercetin and rutin were determined by measurement of isometric tension. Quercetin induced concentration-dependent relaxant responses on acetylcholine or histamine precontracted human bronchial rings and with almost equal effectiveness. In terms of potency (pD2) and efficacy (Emax), quercetin is more potent than rutin on relaxant responses of human bronchus. K+ and Ca2+ concentration-dependent contraction curves were inhibited after incubation with increasing concentrations of quercetin. Quercetin potentiated in a concentration-dependent manner the relaxant effects of isoprenaline or sodium nitroprusside. Rutin had no effect on K+-induced contraction and on relaxant activity of isoprenaline or sodium nitroprusside. Our results suggest that the bronchodilator effects of quercetin are modulated by an increase in cyclic nucleotide levels as well as an alteration in availability of Ca2+ to the contractile machinery.展开更多
Objective:To investigate the potentials of the root bark of Annona（A.） senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.Methods:The metha...Objective:To investigate the potentials of the root bark of Annona（A.） senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.Methods:The methanol extract（ME） of the root bark of A.senegalensis was studied in mice using pentylenetetrazole（PTZ） induced convulsions,phenobarbitone induced sleeping time and motor coordination test on rota-rod performance.Acute toxicity and lethality（LD50） lest as well as phytochemical analysis were also carried out.Results:The extract（200,400,800 mg/ kg） exhibited a non- dose dependent significant（P【0.05） delay in the onset of both tonic and clonic phases of seizure induced by PTZ（60 mg/kg,s.c.） as well as offered a 100%protection （200 mg/kg） in mice from PTZ induced seizures.The extract significantly（P【0.05） decreased the latency and increased the duration of phenobarbitone induced sleeping time.At 200 mg/kg, the extract exhibited a significant（P【0.05） motor incoordination.The acute toxicity test revealed an oral LD<sub>50</sub> of 1 2%mg/kg,while the phytochemical studies showed the presence of alkaloids, resins,glycosides,carbohydrate,reducing sugar,flavonoids,terpenoids,saponins and tannins. Conclusion:The extract of A senegalensis possessed anticonvulsant activity with pronounced hypnotic and muscle relaxant effects.展开更多
The paper introduces a monitoring system of muscle relaxant actionduring the anaesthesia operation,which is based on measurement of acceleration.The monitor consists of an acceleration transducer,a nerve stimlation an...The paper introduces a monitoring system of muscle relaxant actionduring the anaesthesia operation,which is based on measurement of acceleration.The monitor consists of an acceleration transducer,a nerve stimlation and a microcomputer unit.The transducer can be fastened to the thumb,and the signal of thethumb movement in response to ulnar nerve stimulation is measured and registeredin the computing unit. In daily clinical practice it has proved possible,using this newapparatus, to achieve reliable evaluation of nuromuscular transimission functionand to contribute to improve anesthesia quality and patient care.展开更多
Objective To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. Methods...Objective To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. Methods Phenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs. Results Matrine （1×10^-4 mol/L -3.3×10^-3 mol/L） relaxed the endothelium-denuded aortic rings pre-contracted sub-maximally with phenylephrine, in a concentration-dependent manner, and its pre-incubation （3.3× 10^- 3 mol/L） produced a significant rightward shift in the phenylephrine dose-response curve, but had no effects on the potassium chloride-induced contraction. The anti-contractile effect of matrine was not reduced by the highly selective ATP-dependent K^＋ channel blocker glibenclamide （10.5 mol/L）, either by the non-selective K^＋channel blocker tetraethylammonium （10^-3 mol/L）, or by the β-antagonist propranolol （10^-5 mol/L）. In either ＂normal＂ or ＂Ca^2＋-free＂ bathing medium, the phenylephrine-induced contraction was attenuated by matrine （3.3×10^-3 mol/L）, indicating that the vasorelaxation was due to inhibition of intracellular and extracellular Ca^2＋ mobilization. Conclusion Matrine inhibits phenylephrine-induced contractions by inhibiting activation of α-adrenoceptor and interfering with the release of intracellular Ca^2＋ and the influx of extracellular Ca^2＋.展开更多
Compounds with dual action on cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） may be a treatment option for erectile dysfunction, as they not only promote penile erection but also p...Compounds with dual action on cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） may be a treatment option for erectile dysfunction, as they not only promote penile erection but also prevent the upregulation of phosphodiesterase-5. In this study, we examined the possible relaxant effect and mechanism of 17-nor-subincanadine E （SEC, 0.2-200 pmol I^-1）, a plant-derived alkaloid, in rabbit corpus cavernosum （RbCC） strips that had been precontracted by exposure to phenylephrine （10 pmol I^- 1） or a high concentration of K＋ （60 mmol I^- 1） in vitro. In addition to SEC＇s effect on cAMP and cGMP levels, electrical field stimulation （EFS） in phenylephrine-precontracted RbCC and calcium chloride （1-100 mmol I^-1） evoked responses in depolarized RbCC were analysed. SEC relaxed the phenylephrine-precontracted RbCCs in a concentration-dependent manner. Atropine, guanethidine and N-co-nitro-L-arginine methyl ester （L-NAME） did not have any effect on the relaxation of RBCCs. When 1H-1,2,4oxadiazole[4,3-a] quinoxalin-1-one （ODQ） was added, it effectively blocked the relaxant response of SEC. Although SEC enhanced the maximal relaxation produced by sodium nitroprusside （SNP） and forskolin in phenylephrine-precontracted cavernosal smooth muscle, it caused a decrease in the maximal contractile response induced by calcium chloride in depolarized RbCCs. The relaxant effect of SEC was paralleled by an increase in the tissue levels of the Cyclic nucleotides cAMP and cGMP. We conclude that SEC promotes the relaxation of RbCC, possibly favouring cAMP and cGMP accumulation and calcium blockade. This novel mechanism could be useful for patients who do not benefit from phosphodiesterase inhibitors and for those with endothelial and nitrergic dysfunction, such as patients with diabetes, hypertension and dyslipidaemias.展开更多
Background: Development and maintenance of penile erection requires the relaxation of corpus cavernosum smooth muscle (CCSM) cells and it is essentially mediated by nitric oxide (NO). Pausinystalia yohimbe bark is tra...Background: Development and maintenance of penile erection requires the relaxation of corpus cavernosum smooth muscle (CCSM) cells and it is essentially mediated by nitric oxide (NO). Pausinystalia yohimbe bark is traditionally used for the treatment of erectile dysfunction (ED). Objectives and Methods: This study aimed to evaluate the effects of the methanolic extract of P. yohimbe bark (10 mg/ml) on isolated rabbit corpus cavernosum smooth muscle (CCSM). Results: Methanolic extract of P. yohimbe bark blocked contractions in CCSM induced by adrenergic agonists, through facilitating NO release from the endothelial cells. Conclusion: The obtained results revealed that, methanolic extract of P. yohimbe bark caused relaxation of CCSM that validates its traditional aphrodisiac property, thus it could be used to initiate and maintain erection in cases of erectile dysfunction.展开更多
Objective： To examine the relaxant effects of hydro-ethanolic, macerated aqueous （MA） and lipid- free macerated aqueous （LFMA） extract of Tymus vulgaris on tracheal chains of guinea pigs. Methods： The relaxant e...Objective： To examine the relaxant effects of hydro-ethanolic, macerated aqueous （MA） and lipid- free macerated aqueous （LFMA） extract of Tymus vulgaris on tracheal chains of guinea pigs. Methods： The relaxant effects of five cumulative concentrations of each extract （0.4, 0.8, 1.2, 1.6 and 2.0 g/100 mL） were compared with saline as negative control and five cumulative concentrations of theophylline （0.1, 0.2, 0.4, 0.6 and 0.8 mmol/L） on precontracted tracheal smooth muscle of guinea pig with 60 mmol/L KCl （group 1） and 10 μmol/L methacholine （group 2, n=6 for each group）. Results： In group 1 all concentrations of theophylline, three higher concentrations of hydro-ethanolic, two concentrations of LFMA and last concentration of MA extracts showed significant relaxant effects compared with that of saline （P〈0.05 or P〈0.01）. Two lower concentrations of LFMA and all concentrations of MA except higher one caused contraction compared with saline （P〈0.05 or 0.01）. In group 2 experiments, all concentrations of theophylline, hydro-ethanolic, MA and LFMA extracts showed significant relaxant effects compared to that of saline （P〈0.05 or P〈0.01）. In both groups, the relaxant effect of all concentrations of hydro-ethanolic extract were significantly higher than most concentrations of others （P〈0.05 or P〈0.01）. The relaxant effect of different concentrations of three extracts were significantly greater in group 2 compared with group 1 experiments （all P〈0.01）. There were significantly positive correlations between the relaxant effects and concentrations for theophylline and all extracts in both groups （P〈0.05 or P〈0.01）. Conclusion： Hydro-ethanolic extract has a potent weaker relaxant effect for other extracts from Tymus vulgaris on tracheal chains of guinea pigs.展开更多
Background:Component compatibility is important to the modernization of traditional Chinese medicine.Studies have shown that San-ao decoction(SAD)can treat respiratory diseases by relaxing airway smooth muscle(ASM)and...Background:Component compatibility is important to the modernization of traditional Chinese medicine.Studies have shown that San-ao decoction(SAD)can treat respiratory diseases by relaxing airway smooth muscle(ASM)and reducing airway hyper-responsiveness.However,whether its bioactive components and compatibility also present with similar relaxant effects remains unknown.This study aims to explore the potential relaxant property,dose-response relationship,and underlying mechanisms of the bioactive component compatibility in SAD.Methods:Network pharmacology was primarily used to identify the bioactive components of SAD and uncover its underlying mechanisms.ASM tension force measuring technique was utilized to verify the relaxant and dose-response effects on in vitro guinea pig ASM.Results:We postulated pseudoephedrine hydrochloride(PH),amygdalin(AM),and diammonium glycyrrhizate(DG)to be the bioactive components of SAD,which could effectively relax ASM in a dose-dependent manner on both acetylcholine-induced and spontaneous contraction.Both PH and AM could lead to DG dose–response curve shift.The regression equation of these three bioactive components was Y=-2.048×X_(1)+0.411×X_(2)+14.052×X_(3)(X_(1),X_(2),X_(3)representing PH,AM,and DG,respectively).The underlying mechanisms of these components might be associated with the regulation of smooth muscle contraction.Conclusions:PH,AM,and DG are the bioactive components of SAD,which can relax ASM in a dose–response manner and exert a synergistic effect.Clinically,compatibility of these three bioactive components may serve as a new complementary and alternative treatment for respiratory diseases.展开更多
It’s never too early in the year to start planning a break from the stress of city life,and southwest China’s charming Guizhou Province is a destination that should be right at the top of your list.
BACKGROUND Thiocolchicoside(TCC),a muscle relaxant with anti-inflammatory properties,is often used alongside nonsteroidal anti-inflammatory drugs(NSAIDs)to treat musculoskeletal pain.This synergistic approach leverage...BACKGROUND Thiocolchicoside(TCC),a muscle relaxant with anti-inflammatory properties,is often used alongside nonsteroidal anti-inflammatory drugs(NSAIDs)to treat musculoskeletal pain.This synergistic approach leverages the complementary mechanisms of action,providing more effective relief for conditions such as arthritis,muscle spasms,and soft tissue injuries.AIM To evaluate the comparative efficacy of the combination therapy of TCC and NSAIDs vs NSAID monotherapy in pain management.METHODS A systematic search of PubMed and Google Scholar databases through October 2024 was performed to evaluate the effectiveness of combined TCC and NSAID therapy vs NSAIDs alone.A retrospective analysis of electronic medical records from India spanning 3 years(2020-2023)examined treatment patterns and focused on clinical outcomes including pain relief,functional improvement,and adverse effects.Key metrics for assessment included visual analog scale scores and hand-to-floor distance,with secondary outcomes assessing patient satisfaction and adverse event(AE)incidence.RESULTS A systematic literature search revealed seven studies,involving 1137 subjects,aligning with the eligibility criteria from a total of 833 hits.Combination therapy using parenteral TCC with NSAIDs significantly reduced pain intensity[standardised mean difference(SMD):-1.33,P<0.001]and enhanced functional improvement(SMD:-1.08,P<0.001)compared to NSAIDs alone.Patients on combination therapy are 6.7 times more likely to experience over 30%pain relief and 5.2 times more likely to achieve over 50%pain relief.Post surgery pain reduction and patient satisfaction were notably higher in the combination group[odds ratio(OR)=10.14,P<0.001].There were no significant differences in mild/moderate AE rates between the groups(OR=1.30,P=0.378).CONCLUSION Evidence indicates that multimodal therapy,including parenteral TCC with NSAIDs,provides quicker and effective pain relief,reduces muscle spasms,and improves hand-to-floor distance compared to using NSAIDs or TCC alone.展开更多
Although the plastic loading can enhance creep deformation and yield strength,the anisotropic Stress Relaxation Aging(SRA)behavior and mechanism under plastic loading remain unclear,which presents a significant challe...Although the plastic loading can enhance creep deformation and yield strength,the anisotropic Stress Relaxation Aging(SRA)behavior and mechanism under plastic loading remain unclear,which presents a significant challenge in accurately shaping aluminum alloy panels.In this study,the SRA behavior of 2195-T4 Al-Cu-Li alloys were thoroughly studied under initial loading stresses within the elastic(210/250 MPa)and plastic(380/420 MPa)ranges at 180℃by stress relaxation and tensile tests as well as microstructure characterization.The findings reveal that compared with those under elastic loadings,in-plane anisotropy(IPA)values of the stress relaxation amount,yield strength and fracture elongation under plastic loadings are reduced by 60%–80%,70%–90% and 72%–89%,respectively.Similarly,IPA values of precipitate size in grains and PrecipitationFree Zones(PFZ)width at grain boundaries under plastic loading decrease by 31.4%and 94.4%respectively.These results indicate plastic loading significantly weakens the anisotropic SRA behavior,owing to numerous uniformly distributed fine T1phases and small IPA values of both T1precipitates size and PFZ width in various loading directions.Compared with those of elastic loadingaged alloys,yield strength of plastic loading-aged alloys shows high strength-ductility because of the combined effect of closely dispersed fine T1precipitates,narrowed PFZ and numerous sheared and rotated T1phases at different locations during tensile process.The uniformly distributed larger Kernel Average Misorientation(KAM)and Schmidt factor values of the plastic loading-aged alloy,as well as the cross-slip generated,also help to enhance the strength and ductility of the alloy.展开更多
Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the de...Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.展开更多
BACKGROUND Most patients who were included in previous studies on achalasia had increased lower esophageal sphincter(LES)pressure.Peroral endoscopic myotomy(POEM)has been confirmed to be effective at relieving the cli...BACKGROUND Most patients who were included in previous studies on achalasia had increased lower esophageal sphincter(LES)pressure.Peroral endoscopic myotomy(POEM)has been confirmed to be effective at relieving the clinical symptoms of achalasia associated with increased LES pressure.AIM To identify the safety and efficacy of POEM for patients with normal LES integrated relaxation pressure(LES-IRP).METHODS The clinical data of patients who underwent POEM successfully in The First Medical Center of Chinese PLA General Hospital were retrospectively analyzed.A total of 481 patients who underwent preoperative high-resolution manometry(HRM)at our hospital were ultimately included in this research.According to the HRM results,the patients were divided into two groups:71 patients were included in the normal LES-IRP group(LES-IRP<15 mmHg)and 410 patients were included in the increased LES-IRP group(LES-IRP≥15 mmHg).Clinical characteristics,procedure-related parameters,adverse events,and outcomes were compared between the two groups to evaluate the safety and efficacy of POEM for patients with normal LES-IRP.RESULTS Among the 481 patients included in our study,209 were males and 272 were females,with a mean age of 44.2 years.All patients underwent POEM without severe adverse events.The median pre-treatment Eckardt scores of the normal LES-IRP and increased LES-IRP groups were 7.0 and 7.0(P=0.132),respectively,decreasing to 1.0 and 1.0 post-treatment(P=0.572).The clinical success rate of the normal LES-IRP group was 87.3%(62/71),and that of the increased LES-IRP group was 91.2%(374/410)(P=0.298).Reflux symptoms were measured by the GerdQ questionnaire,and the percentages of patients with GerdQ scores≥9 in the normal LES-IRP and increased LES-IRP groups were 8.5%and 10.7%,respectively(P=0.711).After matching,the rates of clinical success and the rates of GerdQ score≥9 were not significantly different between the two groups.CONCLUSION Our results suggest that POEM is safe and effective for achalasia and patients with normal LES-IRP.In addition,in patients with normal LES-IRP,compared with those with increased LES-IRP,POEM was not associated with a greater incidence of reflux symptoms.展开更多
All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid...All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid electrolyte plays a vital role in the performance of working ASSLBs,which is challenging to investigate quantitatively by experimental approach.This work proposed a quantitative model based on the finite element method for electrochemical impedance spectroscopy simulation of different solid-solid contact states in ASSLBs.With the assistance of an equivalent circuit model and distribution of relaxation times,it is discovered that as the number of voids and the sharpness of cracks increase,the contact resistance Rcgrows and ultimately dominates the battery impedance.Through accurate fitting,inverse proportional relations between contact resistance Rcand(1-porosity)as well as crack angle was disclosed.This contribution affords a fresh insight into clarifying solid-solid contact states in ASSLBs.展开更多
In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order hom...In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.展开更多
Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the die...Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the dielectric and relaxor properties of NBT,various dopants such as Sr,K,Li and Bi are incorporated into the NBT structure.These modifications significantly alter the dielectric constant and relaxation behavior,demonstrating a dominant influence of dopant on the material properties.Among these,the solid solution of BaTiO_(3)(BT)with NBT is widely investigated due to its ability to stabilize the perovskite structure and improve dielectric performance.However,the temperature-dependent stability of dielectric properties remains a critical challenge for high-temperature applications.In this study,(1-x)(0.75Na_(0.5)Bi_(0.5)TiO_(3)-0.25BaTiO_(3))-xBaZrO_(3)(NBT-BT-xBZ,x=0,0.08,0.14,and 0.20)ceramics were prepared by a solid-state reaction method.The effect of BaZrO_(3)(BZ)addition on the structural,dielectric,and energy storage properties was systematically investigated.In addition,the phase transition and relaxation behaviors were also analyzed based on the modified Curie-Weiss law,Vogel-Fulcher relation,and Lorentz-type empirical law.Methods The starting materials were powders of high purity Na_(2)CO_(3),Bi_(2)O_(3),TiO_(2),BaCO_(3),and ZrO_(2).The powders were weighed according to a stoichiometric ratio(with 1%excess of Na and Bi)and ground with ethanol in a ball mill at 300 r/min for more than 12 h,and the weight ratio of raw material to ethanol and zirconium balls was 1:1:2.The dried material was heat-treated at 850℃ for 2 h to promote the formation of NBT-BT-BZ.After further grinding for 12 h,the samples were mixed with a small amount of polyvinyl alcohol(PVA).The samples were sintered in air at 1150℃for 2 h and cooled to room temperature.The phase composition of the ceramic samples was determined by an model D8 ADVANDCE X-ray diffractometer(D8 ADVANDCEXRD,Bruker AXS Ltd.,Germany)with Cu target Kαrays,at X-ray wavelengthλof 1.5406Å,2θin the range of 10°to 80°,applied voltage of 40 kV,and a current of 500 mA.A silver paste was coated on the two surfaces as electrodes and heat-treated at 700℃ for 10 min.The dielectric properties of the ceramic samples were determined at different frequencies by a model DMS-1000 high-temperature dielectric temperature spectroscope(BALAB Tech.Co.,China)with at a ramp rate of 3(°)/min in a temperature range from room temperature to 450℃.The overdamped(200Ω)discharge tests for bulk ceramic samples were performed by a model CFD-005 discharge tester(Gogo(GG)Instruments Technology,China)).Results and discussion The XRD patterns indicate that all the ceramic samples have a perovskite structure without any detectable secondary phase,proving that zirconium ions can completely enter the lattice and form a solid solution.Based on the locally magnified XRD peaks,the XRD peak shape shifts towards lower angles as a whole as the BZ content increases.This indicates that the overall volume of the crystal cell shows an expansion as the Zr ions replace Ti ions due to different ionic radii of Zr and Ti ions.The SEM images show that the grain size gradually increases with increasing the BZ content.The addition of BZ promotes the grain growth.However,this gradually slows down with the increase of content up to x of 0.20.The limited grain size variation appears in the latter two samples.All the samples show a relatively dense morphology.The Curie temperature of the NBT-0.25BT ceramic samples is 256℃,which is similar to the reported results.The Curie temperature decreases gradually with the increase of BZ additive,and the dielectric temperature spectrum flattens out,indicating that the enhanced structural and temperature stability of the NBT-BT-BZ ceramics.The maximum values of all dielectric constants correspond to temperatures that increase with frequency,indicating a dielectric relaxor behavior.A frequency dispersion is accompanied at near the Curie temperature,which can be ascribed to the thermal evolution of the tetragonal polar nanoregions(PNRs)and the mixing effect of the transition from tripartite to tetragonal PNRs.Theγvalues obtained from the experimental data at 100 kHz are 1.79,1.83,1.89,and 1.92 for NBT-BT,NBT-BT-0.08BZ,NBT-BT-0.14BZ,and NBT-BT-0.20BZ,respectively.Theγvalue increases gradually with the addition of the BZ content,showing an enhanced relaxation of the NBT-BT-BZ ceramics.The comparison of discharge current curves and energy density of all the ceramics indicate that the addition of BZ significantly improves the discharge current and energy storage performance.A high discharging energy density(Wd)of 1.6 J·cm^(-3) with a fast discharging speed(τ0.9)of 75 ns is obtained for the ceramic samples with x of 0.14.This can be attributed to an increased relaxation as the BZ content increases.Conclusions NBT-BT-BZ ceramics were prepared by a solid-state reaction method.The XRD patterns revealed a phase transition from a tetragonal phase to a pseudocubic phase as the BZ content increased.The dielectric relaxation behavior of the ceramics could be described by three empirical laws(i.e.,modified Curie-Weiss law,Vogel-Fulcher relation and Lorentz-type empirical law).The dielectric relaxation followed the modified Curie-Weiss law and the Vogel-Fulcher relationship.The parametersγand Ea,which were obtained to evaluate the relaxation behavior,increased at a higher BZ content.The Lorentz-type relationship effectively described the temperature dependence of the dielectric constant on both the low-and high-temperature sides within a specific temperature range for all the ceramics.展开更多
In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise c...In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this.展开更多
The dynamics of biomolecules span across a wide range of timescales,reflecting the complexity of free energy landscapes of biomolecules.Among these,the microsecond-tomillisecond(μs-ms)timescale dynamics are particula...The dynamics of biomolecules span across a wide range of timescales,reflecting the complexity of free energy landscapes of biomolecules.Among these,the microsecond-tomillisecond(μs-ms)timescale dynamics are particularly significant,offering detailed insights into the kinetic,thermodynamic,and structural aspects of biological function.Many critical biological processes,including enzyme catalysis,protein folding,ligand binding,and allosteric regulation,operate within this timescale.Nuclear magnetic resonance(NMR)spectroscopy is a powerful technique for probing molecular dynamics in this time window,commonly used NMR methods for investigatingμs-ms timescale dynamics include Carr-Purcell-Meiboom-Gill(CPMG)relaxation dispersion,chemical exchange saturation transfer(CEST),and rotating-frame longitudinal relaxation dispersion(R_(1ρ)relaxation dispersion).This review provides a brief ove rview of the fundamental principles and some recent advances of these methods,highlighting their interrelationships and applications in elucidating biomolecular dynamics.展开更多
The heavy-atom effect of halogen(Br and I)has been widely employed for boosting spin-crossover in organic molecules,while recent investigation indicated halogen-substitution can also enhance fluorescence and even lead...The heavy-atom effect of halogen(Br and I)has been widely employed for boosting spin-crossover in organic molecules,while recent investigation indicated halogen-substitution can also enhance fluorescence and even lead to aggregation-induced emission(AIE).In this work,we investigated ultrafast excited state dynamics of a halogen-substituted model system,i.e.squaryliums NSQ-R(R=H,Cl,Br,I),by using femtosecond spectroscopy and theoretical approach.Fast external reorganization(Ex-re,~3 ps)and slow internal reorganization(In-re,5-20 ps)were observed,while quantitative fitting indicated halogen-substitution leads to a slower non-radiative S1→S0 decay(k_(NR)^(s))and subsequently enhanced fluorescence emitting.By analyzing the extracted k_(NR)^(s)within theoretical framework of non-radiative transition in the strong coupling regime,a plausible AIE mechanism of NSQs was revealed.Our work provides a clear picture on non-radiative dynamics of halogen-substituted squaryliums,which might be useful for future development of organic dyes.展开更多
基金supported by HEC,Pakistan with grant number112-26510-2PS1-258
文摘Objective: To evaluate the sedative effect of Diospyros lotus L(D. lotus) extract in mice using the open field and Rota rod tests.Methods: For the sedative and muscle relaxants activities of extract/fractions of the plant, invivo open field and phenobarbitone-induced sleeping time were used, while the Roda rod test was employed in animals for the assessment of muscle relaxant activity.Results: Results from this investigation revealed that the extracts of D. lotus have exhibited significant sedative effect in mice(45.98%) at 100 mg/kg i.p. When the extract was partitioned with different solvents, the n-hexane fraction was inactive whereas the chloroform fraction was the most active with 82.67% sedative effect at 50 and 100 mg/kg i.p. On the other hand,the ethyl acetate and n-butanol fractions displayed significant sedative effects(55.65% and40.87%, respectively) at 100 mg/kg i.p. Among the tested extract/fractions, only chloroform and ethyl acetate fractions showed significant(P < 0.05) muscle relaxant activity in the Rota rod test.Conclusions: In short, our study provided scientific background to the traditional uses of D.lotus as sedative.
文摘Increasing epidemiological evidence supports the view, that quercetin has protective roles in a multitude of disease states in human who have a high intake of polyphenols. To investigate the ability of quercetin and its rutinoside, rutin, to modulate the relaxation of human airways smooth muscle and to determine the mechanism (s) of such relaxation, isolated human bronchus rings were suspended in individual organ baths, precontracted with acetylcholine or with histamine and the relaxing effects of quercetin and rutin were determined by measurement of isometric tension. Quercetin induced concentration-dependent relaxant responses on acetylcholine or histamine precontracted human bronchial rings and with almost equal effectiveness. In terms of potency (pD2) and efficacy (Emax), quercetin is more potent than rutin on relaxant responses of human bronchus. K+ and Ca2+ concentration-dependent contraction curves were inhibited after incubation with increasing concentrations of quercetin. Quercetin potentiated in a concentration-dependent manner the relaxant effects of isoprenaline or sodium nitroprusside. Rutin had no effect on K+-induced contraction and on relaxant activity of isoprenaline or sodium nitroprusside. Our results suggest that the bronchodilator effects of quercetin are modulated by an increase in cyclic nucleotide levels as well as an alteration in availability of Ca2+ to the contractile machinery.
文摘Objective:To investigate the potentials of the root bark of Annona（A.） senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.Methods:The methanol extract（ME） of the root bark of A.senegalensis was studied in mice using pentylenetetrazole（PTZ） induced convulsions,phenobarbitone induced sleeping time and motor coordination test on rota-rod performance.Acute toxicity and lethality（LD50） lest as well as phytochemical analysis were also carried out.Results:The extract（200,400,800 mg/ kg） exhibited a non- dose dependent significant（P【0.05） delay in the onset of both tonic and clonic phases of seizure induced by PTZ（60 mg/kg,s.c.） as well as offered a 100%protection （200 mg/kg） in mice from PTZ induced seizures.The extract significantly（P【0.05） decreased the latency and increased the duration of phenobarbitone induced sleeping time.At 200 mg/kg, the extract exhibited a significant（P【0.05） motor incoordination.The acute toxicity test revealed an oral LD<sub>50</sub> of 1 2%mg/kg,while the phytochemical studies showed the presence of alkaloids, resins,glycosides,carbohydrate,reducing sugar,flavonoids,terpenoids,saponins and tannins. Conclusion:The extract of A senegalensis possessed anticonvulsant activity with pronounced hypnotic and muscle relaxant effects.
文摘The paper introduces a monitoring system of muscle relaxant actionduring the anaesthesia operation,which is based on measurement of acceleration.The monitor consists of an acceleration transducer,a nerve stimlation and a microcomputer unit.The transducer can be fastened to the thumb,and the signal of thethumb movement in response to ulnar nerve stimulation is measured and registeredin the computing unit. In daily clinical practice it has proved possible,using this newapparatus, to achieve reliable evaluation of nuromuscular transimission functionand to contribute to improve anesthesia quality and patient care.
基金supported by the Program for New Century Excellent Talents in Universities of the Ministry of Education of China (NCET-06-0916)Ningxia Natural Science Foundation (NZ0782)Ningxia Academic Scientific Research Program (2005-2007)
文摘Objective To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. Methods Phenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs. Results Matrine （1×10^-4 mol/L -3.3×10^-3 mol/L） relaxed the endothelium-denuded aortic rings pre-contracted sub-maximally with phenylephrine, in a concentration-dependent manner, and its pre-incubation （3.3× 10^- 3 mol/L） produced a significant rightward shift in the phenylephrine dose-response curve, but had no effects on the potassium chloride-induced contraction. The anti-contractile effect of matrine was not reduced by the highly selective ATP-dependent K^＋ channel blocker glibenclamide （10.5 mol/L）, either by the non-selective K^＋channel blocker tetraethylammonium （10^-3 mol/L）, or by the β-antagonist propranolol （10^-5 mol/L）. In either ＂normal＂ or ＂Ca^2＋-free＂ bathing medium, the phenylephrine-induced contraction was attenuated by matrine （3.3×10^-3 mol/L）, indicating that the vasorelaxation was due to inhibition of intracellular and extracellular Ca^2＋ mobilization. Conclusion Matrine inhibits phenylephrine-induced contractions by inhibiting activation of α-adrenoceptor and interfering with the release of intracellular Ca^2＋ and the influx of extracellular Ca^2＋.
文摘Compounds with dual action on cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） may be a treatment option for erectile dysfunction, as they not only promote penile erection but also prevent the upregulation of phosphodiesterase-5. In this study, we examined the possible relaxant effect and mechanism of 17-nor-subincanadine E （SEC, 0.2-200 pmol I^-1）, a plant-derived alkaloid, in rabbit corpus cavernosum （RbCC） strips that had been precontracted by exposure to phenylephrine （10 pmol I^- 1） or a high concentration of K＋ （60 mmol I^- 1） in vitro. In addition to SEC＇s effect on cAMP and cGMP levels, electrical field stimulation （EFS） in phenylephrine-precontracted RbCC and calcium chloride （1-100 mmol I^-1） evoked responses in depolarized RbCC were analysed. SEC relaxed the phenylephrine-precontracted RbCCs in a concentration-dependent manner. Atropine, guanethidine and N-co-nitro-L-arginine methyl ester （L-NAME） did not have any effect on the relaxation of RBCCs. When 1H-1,2,4oxadiazole[4,3-a] quinoxalin-1-one （ODQ） was added, it effectively blocked the relaxant response of SEC. Although SEC enhanced the maximal relaxation produced by sodium nitroprusside （SNP） and forskolin in phenylephrine-precontracted cavernosal smooth muscle, it caused a decrease in the maximal contractile response induced by calcium chloride in depolarized RbCCs. The relaxant effect of SEC was paralleled by an increase in the tissue levels of the Cyclic nucleotides cAMP and cGMP. We conclude that SEC promotes the relaxation of RbCC, possibly favouring cAMP and cGMP accumulation and calcium blockade. This novel mechanism could be useful for patients who do not benefit from phosphodiesterase inhibitors and for those with endothelial and nitrergic dysfunction, such as patients with diabetes, hypertension and dyslipidaemias.
文摘Background: Development and maintenance of penile erection requires the relaxation of corpus cavernosum smooth muscle (CCSM) cells and it is essentially mediated by nitric oxide (NO). Pausinystalia yohimbe bark is traditionally used for the treatment of erectile dysfunction (ED). Objectives and Methods: This study aimed to evaluate the effects of the methanolic extract of P. yohimbe bark (10 mg/ml) on isolated rabbit corpus cavernosum smooth muscle (CCSM). Results: Methanolic extract of P. yohimbe bark blocked contractions in CCSM induced by adrenergic agonists, through facilitating NO release from the endothelial cells. Conclusion: The obtained results revealed that, methanolic extract of P. yohimbe bark caused relaxation of CCSM that validates its traditional aphrodisiac property, thus it could be used to initiate and maintain erection in cases of erectile dysfunction.
基金financially supported by Tuberculosis and Lung Research Centre,Tabriz University of Medical Sciences and was performed in Drug Applied Research Centre,Tabriz University of Medical Sciences
文摘Objective： To examine the relaxant effects of hydro-ethanolic, macerated aqueous （MA） and lipid- free macerated aqueous （LFMA） extract of Tymus vulgaris on tracheal chains of guinea pigs. Methods： The relaxant effects of five cumulative concentrations of each extract （0.4, 0.8, 1.2, 1.6 and 2.0 g/100 mL） were compared with saline as negative control and five cumulative concentrations of theophylline （0.1, 0.2, 0.4, 0.6 and 0.8 mmol/L） on precontracted tracheal smooth muscle of guinea pig with 60 mmol/L KCl （group 1） and 10 μmol/L methacholine （group 2, n=6 for each group）. Results： In group 1 all concentrations of theophylline, three higher concentrations of hydro-ethanolic, two concentrations of LFMA and last concentration of MA extracts showed significant relaxant effects compared with that of saline （P〈0.05 or P〈0.01）. Two lower concentrations of LFMA and all concentrations of MA except higher one caused contraction compared with saline （P〈0.05 or 0.01）. In group 2 experiments, all concentrations of theophylline, hydro-ethanolic, MA and LFMA extracts showed significant relaxant effects compared to that of saline （P〈0.05 or P〈0.01）. In both groups, the relaxant effect of all concentrations of hydro-ethanolic extract were significantly higher than most concentrations of others （P〈0.05 or P〈0.01）. The relaxant effect of different concentrations of three extracts were significantly greater in group 2 compared with group 1 experiments （all P〈0.01）. There were significantly positive correlations between the relaxant effects and concentrations for theophylline and all extracts in both groups （P〈0.05 or P〈0.01）. Conclusion： Hydro-ethanolic extract has a potent weaker relaxant effect for other extracts from Tymus vulgaris on tracheal chains of guinea pigs.
基金supported by the Research and Development Foundation of the Beijing University of Chinese Medicine(No.2016-ZXFZJJ-116)。
文摘Background:Component compatibility is important to the modernization of traditional Chinese medicine.Studies have shown that San-ao decoction(SAD)can treat respiratory diseases by relaxing airway smooth muscle(ASM)and reducing airway hyper-responsiveness.However,whether its bioactive components and compatibility also present with similar relaxant effects remains unknown.This study aims to explore the potential relaxant property,dose-response relationship,and underlying mechanisms of the bioactive component compatibility in SAD.Methods:Network pharmacology was primarily used to identify the bioactive components of SAD and uncover its underlying mechanisms.ASM tension force measuring technique was utilized to verify the relaxant and dose-response effects on in vitro guinea pig ASM.Results:We postulated pseudoephedrine hydrochloride(PH),amygdalin(AM),and diammonium glycyrrhizate(DG)to be the bioactive components of SAD,which could effectively relax ASM in a dose-dependent manner on both acetylcholine-induced and spontaneous contraction.Both PH and AM could lead to DG dose–response curve shift.The regression equation of these three bioactive components was Y=-2.048×X_(1)+0.411×X_(2)+14.052×X_(3)(X_(1),X_(2),X_(3)representing PH,AM,and DG,respectively).The underlying mechanisms of these components might be associated with the regulation of smooth muscle contraction.Conclusions:PH,AM,and DG are the bioactive components of SAD,which can relax ASM in a dose–response manner and exert a synergistic effect.Clinically,compatibility of these three bioactive components may serve as a new complementary and alternative treatment for respiratory diseases.
文摘It’s never too early in the year to start planning a break from the stress of city life,and southwest China’s charming Guizhou Province is a destination that should be right at the top of your list.
文摘BACKGROUND Thiocolchicoside(TCC),a muscle relaxant with anti-inflammatory properties,is often used alongside nonsteroidal anti-inflammatory drugs(NSAIDs)to treat musculoskeletal pain.This synergistic approach leverages the complementary mechanisms of action,providing more effective relief for conditions such as arthritis,muscle spasms,and soft tissue injuries.AIM To evaluate the comparative efficacy of the combination therapy of TCC and NSAIDs vs NSAID monotherapy in pain management.METHODS A systematic search of PubMed and Google Scholar databases through October 2024 was performed to evaluate the effectiveness of combined TCC and NSAID therapy vs NSAIDs alone.A retrospective analysis of electronic medical records from India spanning 3 years(2020-2023)examined treatment patterns and focused on clinical outcomes including pain relief,functional improvement,and adverse effects.Key metrics for assessment included visual analog scale scores and hand-to-floor distance,with secondary outcomes assessing patient satisfaction and adverse event(AE)incidence.RESULTS A systematic literature search revealed seven studies,involving 1137 subjects,aligning with the eligibility criteria from a total of 833 hits.Combination therapy using parenteral TCC with NSAIDs significantly reduced pain intensity[standardised mean difference(SMD):-1.33,P<0.001]and enhanced functional improvement(SMD:-1.08,P<0.001)compared to NSAIDs alone.Patients on combination therapy are 6.7 times more likely to experience over 30%pain relief and 5.2 times more likely to achieve over 50%pain relief.Post surgery pain reduction and patient satisfaction were notably higher in the combination group[odds ratio(OR)=10.14,P<0.001].There were no significant differences in mild/moderate AE rates between the groups(OR=1.30,P=0.378).CONCLUSION Evidence indicates that multimodal therapy,including parenteral TCC with NSAIDs,provides quicker and effective pain relief,reduces muscle spasms,and improves hand-to-floor distance compared to using NSAIDs or TCC alone.
基金support from the Key Program of the National Natural Science Foundation of China(No.51235010)。
文摘Although the plastic loading can enhance creep deformation and yield strength,the anisotropic Stress Relaxation Aging(SRA)behavior and mechanism under plastic loading remain unclear,which presents a significant challenge in accurately shaping aluminum alloy panels.In this study,the SRA behavior of 2195-T4 Al-Cu-Li alloys were thoroughly studied under initial loading stresses within the elastic(210/250 MPa)and plastic(380/420 MPa)ranges at 180℃by stress relaxation and tensile tests as well as microstructure characterization.The findings reveal that compared with those under elastic loadings,in-plane anisotropy(IPA)values of the stress relaxation amount,yield strength and fracture elongation under plastic loadings are reduced by 60%–80%,70%–90% and 72%–89%,respectively.Similarly,IPA values of precipitate size in grains and PrecipitationFree Zones(PFZ)width at grain boundaries under plastic loading decrease by 31.4%and 94.4%respectively.These results indicate plastic loading significantly weakens the anisotropic SRA behavior,owing to numerous uniformly distributed fine T1phases and small IPA values of both T1precipitates size and PFZ width in various loading directions.Compared with those of elastic loadingaged alloys,yield strength of plastic loading-aged alloys shows high strength-ductility because of the combined effect of closely dispersed fine T1precipitates,narrowed PFZ and numerous sheared and rotated T1phases at different locations during tensile process.The uniformly distributed larger Kernel Average Misorientation(KAM)and Schmidt factor values of the plastic loading-aged alloy,as well as the cross-slip generated,also help to enhance the strength and ductility of the alloy.
基金supported by the National Natural Science Foundation of China(52476200,52106244)the Guangdong Basic and Applied Basic Research Foundation(2024A1515030124)+1 种基金the Science and Technology Project of China Southern Power Grid under Grant GDKJXM20230246(030100KC23020017)the Fundamental Research Funds for the Central Universities。
文摘Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.
文摘BACKGROUND Most patients who were included in previous studies on achalasia had increased lower esophageal sphincter(LES)pressure.Peroral endoscopic myotomy(POEM)has been confirmed to be effective at relieving the clinical symptoms of achalasia associated with increased LES pressure.AIM To identify the safety and efficacy of POEM for patients with normal LES integrated relaxation pressure(LES-IRP).METHODS The clinical data of patients who underwent POEM successfully in The First Medical Center of Chinese PLA General Hospital were retrospectively analyzed.A total of 481 patients who underwent preoperative high-resolution manometry(HRM)at our hospital were ultimately included in this research.According to the HRM results,the patients were divided into two groups:71 patients were included in the normal LES-IRP group(LES-IRP<15 mmHg)and 410 patients were included in the increased LES-IRP group(LES-IRP≥15 mmHg).Clinical characteristics,procedure-related parameters,adverse events,and outcomes were compared between the two groups to evaluate the safety and efficacy of POEM for patients with normal LES-IRP.RESULTS Among the 481 patients included in our study,209 were males and 272 were females,with a mean age of 44.2 years.All patients underwent POEM without severe adverse events.The median pre-treatment Eckardt scores of the normal LES-IRP and increased LES-IRP groups were 7.0 and 7.0(P=0.132),respectively,decreasing to 1.0 and 1.0 post-treatment(P=0.572).The clinical success rate of the normal LES-IRP group was 87.3%(62/71),and that of the increased LES-IRP group was 91.2%(374/410)(P=0.298).Reflux symptoms were measured by the GerdQ questionnaire,and the percentages of patients with GerdQ scores≥9 in the normal LES-IRP and increased LES-IRP groups were 8.5%and 10.7%,respectively(P=0.711).After matching,the rates of clinical success and the rates of GerdQ score≥9 were not significantly different between the two groups.CONCLUSION Our results suggest that POEM is safe and effective for achalasia and patients with normal LES-IRP.In addition,in patients with normal LES-IRP,compared with those with increased LES-IRP,POEM was not associated with a greater incidence of reflux symptoms.
基金supported by the Beijing Natural Science Foundation(Z200011,L233004)the National Key Research and Development Program(2021YFB2500300)+3 种基金the National Natural Science Foundation of China(52394170,52394171,22109011,22393900,and 22108151)the Tsinghua-Jiangyin Innovation Special Fund(TJISF)(2022JYTH0101)the S&T Program of Hebei(22344402D)the Tsinghua University Initiative Scientific Research Program.
文摘All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid electrolyte plays a vital role in the performance of working ASSLBs,which is challenging to investigate quantitatively by experimental approach.This work proposed a quantitative model based on the finite element method for electrochemical impedance spectroscopy simulation of different solid-solid contact states in ASSLBs.With the assistance of an equivalent circuit model and distribution of relaxation times,it is discovered that as the number of voids and the sharpness of cracks increase,the contact resistance Rcgrows and ultimately dominates the battery impedance.Through accurate fitting,inverse proportional relations between contact resistance Rcand(1-porosity)as well as crack angle was disclosed.This contribution affords a fresh insight into clarifying solid-solid contact states in ASSLBs.
基金support by the National Key R&D Program of China(Grant No.2023YFA1008901)the National Natural Science Foundation of China(Grant Nos.11988102,12172009)is gratefully acknowledged.
文摘In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.
基金国家自然科学基金(12104188,12474095 and 52402323)开放基金(2023KF03,KYCX24-4102)。
文摘Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the dielectric and relaxor properties of NBT,various dopants such as Sr,K,Li and Bi are incorporated into the NBT structure.These modifications significantly alter the dielectric constant and relaxation behavior,demonstrating a dominant influence of dopant on the material properties.Among these,the solid solution of BaTiO_(3)(BT)with NBT is widely investigated due to its ability to stabilize the perovskite structure and improve dielectric performance.However,the temperature-dependent stability of dielectric properties remains a critical challenge for high-temperature applications.In this study,(1-x)(0.75Na_(0.5)Bi_(0.5)TiO_(3)-0.25BaTiO_(3))-xBaZrO_(3)(NBT-BT-xBZ,x=0,0.08,0.14,and 0.20)ceramics were prepared by a solid-state reaction method.The effect of BaZrO_(3)(BZ)addition on the structural,dielectric,and energy storage properties was systematically investigated.In addition,the phase transition and relaxation behaviors were also analyzed based on the modified Curie-Weiss law,Vogel-Fulcher relation,and Lorentz-type empirical law.Methods The starting materials were powders of high purity Na_(2)CO_(3),Bi_(2)O_(3),TiO_(2),BaCO_(3),and ZrO_(2).The powders were weighed according to a stoichiometric ratio(with 1%excess of Na and Bi)and ground with ethanol in a ball mill at 300 r/min for more than 12 h,and the weight ratio of raw material to ethanol and zirconium balls was 1:1:2.The dried material was heat-treated at 850℃ for 2 h to promote the formation of NBT-BT-BZ.After further grinding for 12 h,the samples were mixed with a small amount of polyvinyl alcohol(PVA).The samples were sintered in air at 1150℃for 2 h and cooled to room temperature.The phase composition of the ceramic samples was determined by an model D8 ADVANDCE X-ray diffractometer(D8 ADVANDCEXRD,Bruker AXS Ltd.,Germany)with Cu target Kαrays,at X-ray wavelengthλof 1.5406Å,2θin the range of 10°to 80°,applied voltage of 40 kV,and a current of 500 mA.A silver paste was coated on the two surfaces as electrodes and heat-treated at 700℃ for 10 min.The dielectric properties of the ceramic samples were determined at different frequencies by a model DMS-1000 high-temperature dielectric temperature spectroscope(BALAB Tech.Co.,China)with at a ramp rate of 3(°)/min in a temperature range from room temperature to 450℃.The overdamped(200Ω)discharge tests for bulk ceramic samples were performed by a model CFD-005 discharge tester(Gogo(GG)Instruments Technology,China)).Results and discussion The XRD patterns indicate that all the ceramic samples have a perovskite structure without any detectable secondary phase,proving that zirconium ions can completely enter the lattice and form a solid solution.Based on the locally magnified XRD peaks,the XRD peak shape shifts towards lower angles as a whole as the BZ content increases.This indicates that the overall volume of the crystal cell shows an expansion as the Zr ions replace Ti ions due to different ionic radii of Zr and Ti ions.The SEM images show that the grain size gradually increases with increasing the BZ content.The addition of BZ promotes the grain growth.However,this gradually slows down with the increase of content up to x of 0.20.The limited grain size variation appears in the latter two samples.All the samples show a relatively dense morphology.The Curie temperature of the NBT-0.25BT ceramic samples is 256℃,which is similar to the reported results.The Curie temperature decreases gradually with the increase of BZ additive,and the dielectric temperature spectrum flattens out,indicating that the enhanced structural and temperature stability of the NBT-BT-BZ ceramics.The maximum values of all dielectric constants correspond to temperatures that increase with frequency,indicating a dielectric relaxor behavior.A frequency dispersion is accompanied at near the Curie temperature,which can be ascribed to the thermal evolution of the tetragonal polar nanoregions(PNRs)and the mixing effect of the transition from tripartite to tetragonal PNRs.Theγvalues obtained from the experimental data at 100 kHz are 1.79,1.83,1.89,and 1.92 for NBT-BT,NBT-BT-0.08BZ,NBT-BT-0.14BZ,and NBT-BT-0.20BZ,respectively.Theγvalue increases gradually with the addition of the BZ content,showing an enhanced relaxation of the NBT-BT-BZ ceramics.The comparison of discharge current curves and energy density of all the ceramics indicate that the addition of BZ significantly improves the discharge current and energy storage performance.A high discharging energy density(Wd)of 1.6 J·cm^(-3) with a fast discharging speed(τ0.9)of 75 ns is obtained for the ceramic samples with x of 0.14.This can be attributed to an increased relaxation as the BZ content increases.Conclusions NBT-BT-BZ ceramics were prepared by a solid-state reaction method.The XRD patterns revealed a phase transition from a tetragonal phase to a pseudocubic phase as the BZ content increased.The dielectric relaxation behavior of the ceramics could be described by three empirical laws(i.e.,modified Curie-Weiss law,Vogel-Fulcher relation and Lorentz-type empirical law).The dielectric relaxation followed the modified Curie-Weiss law and the Vogel-Fulcher relationship.The parametersγand Ea,which were obtained to evaluate the relaxation behavior,increased at a higher BZ content.The Lorentz-type relationship effectively described the temperature dependence of the dielectric constant on both the low-and high-temperature sides within a specific temperature range for all the ceramics.
文摘In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this.
基金financially supported by funds from the Natural Science Foundation of Beijing Municipality(Grant Number 7232251)the National Natural Science Foundation of China(Grant Number 22474006)。
文摘The dynamics of biomolecules span across a wide range of timescales,reflecting the complexity of free energy landscapes of biomolecules.Among these,the microsecond-tomillisecond(μs-ms)timescale dynamics are particularly significant,offering detailed insights into the kinetic,thermodynamic,and structural aspects of biological function.Many critical biological processes,including enzyme catalysis,protein folding,ligand binding,and allosteric regulation,operate within this timescale.Nuclear magnetic resonance(NMR)spectroscopy is a powerful technique for probing molecular dynamics in this time window,commonly used NMR methods for investigatingμs-ms timescale dynamics include Carr-Purcell-Meiboom-Gill(CPMG)relaxation dispersion,chemical exchange saturation transfer(CEST),and rotating-frame longitudinal relaxation dispersion(R_(1ρ)relaxation dispersion).This review provides a brief ove rview of the fundamental principles and some recent advances of these methods,highlighting their interrelationships and applications in elucidating biomolecular dynamics.
基金support by the National Key R&D Program of China(Nos.2020YFA0714603 and 2020YFA0714604)。
文摘The heavy-atom effect of halogen(Br and I)has been widely employed for boosting spin-crossover in organic molecules,while recent investigation indicated halogen-substitution can also enhance fluorescence and even lead to aggregation-induced emission(AIE).In this work,we investigated ultrafast excited state dynamics of a halogen-substituted model system,i.e.squaryliums NSQ-R(R=H,Cl,Br,I),by using femtosecond spectroscopy and theoretical approach.Fast external reorganization(Ex-re,~3 ps)and slow internal reorganization(In-re,5-20 ps)were observed,while quantitative fitting indicated halogen-substitution leads to a slower non-radiative S1→S0 decay(k_(NR)^(s))and subsequently enhanced fluorescence emitting.By analyzing the extracted k_(NR)^(s)within theoretical framework of non-radiative transition in the strong coupling regime,a plausible AIE mechanism of NSQs was revealed.Our work provides a clear picture on non-radiative dynamics of halogen-substituted squaryliums,which might be useful for future development of organic dyes.
