This paper represents a detailed and systematic review of one of the most ongoing applications of computational fluid dynamics(CFD)in biomedical applications.Beyond its various engineering applications,CFD has started...This paper represents a detailed and systematic review of one of the most ongoing applications of computational fluid dynamics(CFD)in biomedical applications.Beyond its various engineering applications,CFD has started to establish a presence in the biomedical field.Cardiac abnormality,a familiar health issue,is an essential point of investigation by research analysts.Diagnostic modalities provide cardiovascular structural information but give insufficient information about the hemodynamics of blood.The study of hemodynamic parameters can be a potential measure for determining cardiovascular abnormalities.Numerous studies have explored the rheological behavior of blood experimentally and numerically.This paper provides insight into how researchers have incorporated the pulsatile nature of the blood experimentally,numerically,or through various simulations over the years.It focuses on how machine learning platforms derive outputs based on mass and momentum conservation to predict the velocity and pressure profile,analyzing various cardiac diseases for clinical applications.This will pave the way toward responsive AI in cardiac healthcare,improving productivity and quality in the healthcare industry.The paper shows how CFD is a vital tool for efficiently studying the flow in arteries.The review indicates this biomedical simulation and its applications in healthcare using machine learning and AI.Developing AI-based CFD models can impact society and foster the advancement towards responsive AI.展开更多
BACKGROUND Pituitary stalk interruption syndrome(PSIS)is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes.It is characterized by a deficiency in anterior pitui...BACKGROUND Pituitary stalk interruption syndrome(PSIS)is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes.It is characterized by a deficiency in anterior pituitary hormones,such as growth hormone,gonadotropins,and thyroid hormones.Due to the syndrome's rarity and nonspecific manifestations,there is a lack of standardized treatment strategies.Consequently,early diagnosis through imaging and on-time intervention are crucial for improving patients’outcomes.CASE SUMMARY A 30-year-old man presented with absent secondary sexual characteristics and azoospermia.Laboratory evaluation revealed a deficiency in gonadotropins,while thyroid function was mostly within normal ranges.Magnetic resonance imaging of the pituitary gland showed pituitary stalk agenesis,hypoplasia of the anterior pituitary,and ectopic posterior pituitary,leading to the diagnosis of PSIS.Initially,the patient underwent 6 mo of gonadotropin therapy without significant changes in hormone levels and secondary sexual characteristics.Pulsatile gonadotropin-releasing hormone therapy was then administered,resulting in the detection of sperm in the semen analysis within 3 mo.After 6 mo,routine semen tests showed normal semen quality.The couple faced challenges in conceiving due to abstinence and underwent three cycles of artificial insemination,which was unsuccessful.They also attempted in vitro fertilization,but unfortunately,the woman experienced a miscarriage 10 wk after the embryo transfer.CONCLUSION Early detection,accurate diagnosis,and timely treatment are crucial in improving the quality of life and fertility of PSIS patients.展开更多
Although pulsatile ECMO,as novel kinds of ECMO,has been attracted more and more attention,the differences of the hemodynamic effects of the pulsatile ECMO on the aorta,the cerebral perfusion,and left ventricular work ...Although pulsatile ECMO,as novel kinds of ECMO,has been attracted more and more attention,the differences of the hemodynamic effects of the pulsatile ECMO on the aorta,the cerebral perfusion,and left ventricular work were still under-investigated.The aim of this study was to clarify the hemodynamic differences of the cardiovascular system between the pulsatile and non-pulsatile VA ECMO.In this study,three ECMO support modes,named as“constant flow mode”,“co-pulse mode”and“counter pulse mode”,were designed.The computational fluid dynamics(CFD)study was carried out.The distribution of the oxygenated blood,the blood velocity vector,the oscillatory shear index(OSI),the relative residence time(RRT),the left ventricular external work(EW),the equivalent left ventricular afterload(EAL)and the energy loss of cardiovascular system(EL)were calculated to compare the hemodynamic differences.The simulation results demonstrate that the oxygenated blood under co-pulse mode was easier to perfuse into the three braches vessels than that under both other modes.In addition,the ECMO under counter pulse mode could also achieve lowest RRT(constant flow mode 220 vs.co-pulse mode 132 vs.counter pulse mode 93).Similarly,the ECMO under counter pulse mode could significantly reduce the left ventricular external work(co-pulse mode 1.51 w vs.constant flow mode 1.44 w and counter pulse mode 1.30 w),left ventricular afterload(constant flow mode 1.03 mmHg·s/ml vs.co-pulse mode 1.67 mmHg·s/ml vs.counter pulse mode 0.82 mmHg·s/ml)and energy loss of arterial system(constant flow mode 0.18 w vs.co-pulse mode 0.50 w vs.counter pulse mode 0.16 w).In short,the ECMO under counter pulse mode could have advantages to the left ventricular unloading.In contrast,the ECMO under co-pulse mode has more benefit to cerebral oxygen perfusion.展开更多
Both pulsatile gonadotropin-releasing hormone （GnRH） infusion and combined gonadotropin therapy （human chorionic gonadotropin and human menopausal gonadotropin [HCG/HMG]） are effective to induce spermatogenesis in...Both pulsatile gonadotropin-releasing hormone （GnRH） infusion and combined gonadotropin therapy （human chorionic gonadotropin and human menopausal gonadotropin [HCG/HMG]） are effective to induce spermatogenesis in male patients with congenital hypogonadotropic hypogonadism （CH H）. However, evidence is lacking as to which treatment strategy is better. This retrospective cohort study included 202 patients with CHH： twenty had received pulsatile GnRH and 182 had received HCG/HMG. Patients had received therapy for at least 12 months. The total follow-up time was 15.6 ± 5.0 months （range： 12-27 months） for the GnRH group and 28.7 ± 13.0 months （range： 12-66 months） for the HCG/HMG group. The median time to first sperm appearance was 6 months （95% confidence interval [CI]： 1.6-10.4） in the GnRH group versus 18 months （95% Ch 16.4-20.0） in the HCG/HMG group （P〈 0.001）. The median time to achieve sperm concentrations 〉5 x 106 m1-1 was 14 months （95% Ch 5.8-22.2） in the GnRH group versus 27 months （95% Ch 18.9-35.1） in the HCG/HMG group （P 〈 0.001）, and the median time to concentrations 〉10 x 106 m1-1 was 18 months （95% Ch 10.0-26.0） in the GnRH group versus 39 months （95% CI unknown） in the HCG/HMG group. Compared to the GnRH group, the HCG/HMG group required longer treatment periods to achieve testicular sizes of 〉4 ml, 〉8 ml, 〉12 ml, and 〉16 ml. Sperm motility （a ＋ b ＋ c percentage） evaluated in semen samples with concentrations 〉1 × 106 ml-1 was 43.7% ± 20.4% （16 samples） in the GnRH group versus 43.2% ± 18.1% （153 samples） in the HCG/HMG group （P= 0.921）. Notably, during follow-up, the GnRH group had lower serum testosterone levels than the HCG/HMG group （8.3 ±4.6 vs 16.2 ± 8.2 nmol 1-1, P 〈 0.001）. Our study found that pulsatile GnRH therapy was associated with earlier spermatogenesis and larger testicular size compared to combined gonadotropin therapy. Additional prospective randomized studies would be required to confirm these findings.展开更多
This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneury...This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental findings.The maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm dome.There is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance increased.These results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.展开更多
The effects of the renal artery stenosis （RAS） on the blood flow and vessel walls are investigated. The pulsatile blood flow through an anatomically realistic model of the abdominal aorta and renal arteries reconstr...The effects of the renal artery stenosis （RAS） on the blood flow and vessel walls are investigated. The pulsatile blood flow through an anatomically realistic model of the abdominal aorta and renal arteries reconstructed from CT-scan images is simulated, which incorporates the fluid-structure interaction （FSI）. In addition to the investigation of the RAS effects on the wall shear stress and the displacement of the vessel wall, it is determined that the RAS leads to decrease in the renal mass flow. This may cause the activation of the renin-angiotension system and results in severe hypertension.展开更多
Objective To investigate the etiology,clinical characteristics,diagnosis,and treatment strategies and efficacy of pulsatile tinnitus(PT)caused by vascular anatomy abnormality.Methods The clinical data of 45 patients w...Objective To investigate the etiology,clinical characteristics,diagnosis,and treatment strategies and efficacy of pulsatile tinnitus(PT)caused by vascular anatomy abnormality.Methods The clinical data of 45 patients with PT in our hospital from 2012 to 2019 were collected and retrospectively analyzed.Results All 45 patients had vascular anatomical abnormalities.The patients were divided into 10 categories according to the different locations of vascular abnormalities:sigmoid sinus diverticulum(SSD),sigmoid sinus wall dehiscence(SSWD),SSWD with high jugular bulb,pure dilated mastoid emissary vein,aberrant internal carotid artery(ICA)in the middle ear,transverse-sigmoid sinus(TSS)transition stenosis,TSS transition stenosis with SSD,persistent occipital sinus stenosis,petrous segment stenosis of ICA,and dural arteriovenous fistula.All patients complained of PT synchronous with heartbeat rhythm.Endovascular interventional therapy and extravascular open surgery were used according to the location of the vascular lesions.Tinnitus disappeared in 41 patients,was significantly relieved in 3 patients,and was unchanged in 1 patient postoperatively.Except for one patient with transient headache postoperatively,no obvious complications occurred.Conclusion PT caused by vascular anatomy abnormalities can be identified by detailed medical history and physical and imaging examination.PT can be relieved or even completely alleviated after appropriate surgical treatments.展开更多
Pulsatile gonadotropin-releasing hormone （GnRH） may induce spermatogenesis in most patients with congenital hypogonadotropic hypogonadism （CHH） by stimulating gonadotropin production, while the predictors for a pi...Pulsatile gonadotropin-releasing hormone （GnRH） may induce spermatogenesis in most patients with congenital hypogonadotropic hypogonadism （CHH） by stimulating gonadotropin production, while the predictors for a pituitary response to pulsatile GnRH therapy were rarely investigated. Therefore, the aim of our study is to investigate predictors of the pituitary response to pulsatile GnRH therapy. This retrospective cohort study included 82 CHH patients who received subcutaneous pulsatile GnRH therapy for at least 1 month. Patients were categorized into poor or normal luteinizing hormone （LH） response subgroups according to their LH level （LH 〈2 IU 1-1 or LH P_2 IU 1-1） 1 month into pulsatile GnRH therapy. Gonadotropin and testosterone levels, testicular size, and sperm count were compared between the two subgroups before and after GnRH therapy. Among all patients, LH increased from 0.4±0.5 IUI^-1 to 7.5±4.4 IUI^-1 and follicle-stimulating hormone （FSH） increased from 1.1±0.9 IUI^-1 to 8.8±5.3 IU 1-1. A Cox regression analysis showed that basal testosterone level （6 = 0.252, P = 0.029） and triptorelin-stimulated FSH60min（13 = 0.518, P = 0.01） were two favorable predictors for pituitary response to GnRH therapy. Nine patients （9/82, 11.0%） with low LH response to GnRH therapy were classified into the poor LH response subgroup. After pulsatile GnRH therapy, total serum testosterone level was 39± 28 ng dl^-1 versus 248±158 ng d1^-1 （P=0.001）, and testicular size was 4.0±3.1 ml versus 7.9±4.5 ml （P= 0.005） in the poor and normal LH response subgroups, respectively. It is concluded that higher levels of triptorelin-stimulated FSH60min. and basal total serum testosterone are favorable predictors of pituitary LH response to GnRH therapy.展开更多
BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures ...BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures in PT patients with multiple causes after stenting for ipsilateral transverse sinus stenosis(TSS)have not been previously reported.We report such a case and present postoperative computed tomography venography(CTV)follow-up findings to demonstrate the decreased sigmoid sinus diverticulum and bone remodeling.CASE SUMMARY A 45-year-old man suffered from left-sided PT for 15 years that was occasionally accompanied by headache and dizziness.Pre-operative CTV revealed left-sided sigmoid sinus wall anomalies(SSWAs),TSS,outflow dominance,large posterior condylar emissary vein,and an empty sella turcica.A cerebrospinal fluid pressure of 270 mmH2O was further detected.The sound disappeared immediately after stenting for ipsilateral TSS,with no recurrence during 2 years of follow-up.After the procedure,the patient underwent four consecutive CTV examinations.The diverticulum decreased 6 mo after the procedure with new bone remodeling.The density of the remodeled bone was further increased 1 year later,and a hardened edge was formed 2 years later.CONCLUSION PT associated with SSWAs,TSS,and idiopathic intracranial hypertension can be cured by stenting for TSS alone.And bone remodeling around SSWAs is a more significant finding.展开更多
Lattice sandwich structures are broadly used in aerospace,navigation,and high-speed rail engineering.In engineering practice,the airflow outside the vehicle or aircraft always exhibits the pulsatile property,which mak...Lattice sandwich structures are broadly used in aerospace,navigation,and high-speed rail engineering.In engineering practice,the airflow outside the vehicle or aircraft always exhibits the pulsatile property,which makes the elastic structural components and the external airflow a parametric excitation system.In this paper,the parametric vibration stability analysis and dynamic characteristics of a lattice sandwich plate interacting with the pulsatile external airflow are studied.The equation of motion is derived using Hamilton’s principle and discretized using the assumed mode method.The linear potential flow theory is applied to derive the perturbation aerodynamic pressure.The stability of the system is analyzed using the Floquet theory and validated by numerical simulations.The effects of design parameters of the lattice sandwich plate on the stability of the system are discussed.From the simulations and discussions,some practical principles for the optimal design of lattice sandwich structures in the aerodynamic environment are proposed.展开更多
The aim of this study was to prepare pulsatile release tablets which provide different drug delayed-release time and realize personalized administration according to the needs of patients.Fused deposition modeling(FDM...The aim of this study was to prepare pulsatile release tablets which provide different drug delayed-release time and realize personalized administration according to the needs of patients.Fused deposition modeling(FDM)3D printing technology was introduced into the field of pharmaceutics in this study,and the feasibility to prepare core-shell pulsatile release tablets was explored by combing 3D printing technology with the traditional manufacturing technology.The core of the pulsatile tablets was a commercial tablet obtained from the traditional technology,and the drug-free shell was prepared by the FDM 3D printing technology.Three kinds of tablet shells were designed using different parameters.Furthermore,the morphology,size,weight,hardness,and in vitro drug release of the 3D printed famotidine pusatile tablets were characterized and evaluated.The results showed that the 3D printed tablets appeared intact without any defects.Different parameters of outer shell affected the size,weight,hardness,and in vitro drug release of the tablets.The tablets achieved a personalized delayed release time varying from 5 to 7 h in vitro.In this way,a new method for preparing pulsatile release tablets and a new way for the personalized administration of pulsatile tablets were explored in this study.展开更多
BACKGROUND Pulsatile tinnitus(PT)is an annoying sound that can be eliminated with targeted treatment of the cause.However,the causes of PT have not been fully elucidated.CASE SUMMARY A 38-year-old woman with right-sid...BACKGROUND Pulsatile tinnitus(PT)is an annoying sound that can be eliminated with targeted treatment of the cause.However,the causes of PT have not been fully elucidated.CASE SUMMARY A 38-year-old woman with right-sided objective PT underwent preoperative computed tomography arteriography and venography(CTA/V).A 3.8 mm vine diploic vein(DV),which passed through the mastoid air cells posteriorly in a dehiscent canal and was continuous with the transverse-sigmoid sinus,was thought to be the causative finding.Four-dimensional flow magnetic resonance(4D flow MR)imaging showed that the blood in the DV flowed toward the transverse-sigmoid sinus.The closer the blood was to the transverse-sigmoid sinus,the higher the velocity.No vortex or turbulence was found in the DV or adjacent transverse sinus.The sound was eliminated immediately after ligation of the DV with no recurrence during a three-month follow-up.No flow signal of the DV was noted on postoperative 4D flow MR.CONCLUSION A DV may be a treatable cause of PT.CTA/V and 4D flow MR could be utilized to determine the morphological and hemodynamic characteristics of the DV.展开更多
In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence,(ii) incomple...In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence,(ii) incomplete coalescence and(iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets(mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength,frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.展开更多
In this paper, the pulsatile flow of blood through an inclined catheterized stenosed artery is analyzed. Perturbation method is used to solve the implicit system of partial differential equations with suitable boundar...In this paper, the pulsatile flow of blood through an inclined catheterized stenosed artery is analyzed. Perturbation method is used to solve the implicit system of partial differential equations with suitable boundary conditions. Various analytical expressions axial velocity, flow rate, wall shear stress and effective viscosity have been derived with the help of MATLAB for understanding the fluid flow phenomena. The combined effect of catheterization, body acceleration, slip and inclination has been seen by plotting the graph and observed that axial velocity and flow rate increases with the increase in body acceleration, inclination angle and slip velocity while axial velocity diminishes on increasing the catheter radius. Wall shear stress increases with the increase in catheter radius and body acceleration but presence of slip velocity reduces the wall shear stress. Effective viscosity diminishes on increasing body acceleration and inclination angle, whereas slightly augmented in non-inclined stenosed artery.展开更多
A three-dimensional computational fluid dynamics (CFD) simulation of the physiological pulsatile blood flow in the human aortic arch and its three branches has been conducted by using commercial software StarCD. The b...A three-dimensional computational fluid dynamics (CFD) simulation of the physiological pulsatile blood flow in the human aortic arch and its three branches has been conducted by using commercial software StarCD. The blood flow, of a peak Reynolds number of 3289 and a Womersley parameter of 16.44, was simulated in a rigid aorta geometry that was built by computer aided design (CAD) reconstruction method based on autopsy data of a female adult. The purpose of this work is to further the understanding of the complex nature of aorta flow, therefore it mainly focuses on analysis of the spatial and temporal distributions of velocities and wall shear stresses. The results, illustrated by 3D visualization pictures and 2D graphs of the primary velocity profiles, wall shear stress and pressure distributions, as well as the secondary flow patterns, are in good agreement with those of other experimental and computational works. The distributions of pressure and wall shear stress support the correlation between high and low shear stresses and pressures and the atherosclerotic lesions.展开更多
The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts a...The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts as a low-pass filter, and the biochemical signals are nonlinearly modulated by the pulsatile flows, which depend on the biochemical signal frequency, the flow signal frequency, and the biochemical signal transporting distance. It is concluded that, the transfer characteristics of the dynamic biochemical signals, which are transported in the time-varying flows, should be carefully considered for better loading biochemical signals on the cells cultured on the bottom of the microfluidic channel.展开更多
The escalation of zeta potential by the influence of wall slip for the electrokinetically modulated flow through a microchannel motivates to consider the impact of hydrodynamic slippage upon the zeta or surface potent...The escalation of zeta potential by the influence of wall slip for the electrokinetically modulated flow through a microchannel motivates to consider the impact of hydrodynamic slippage upon the zeta or surface potential.The reported study undergoes an analytical exploration of the pulsatile electroosmosis and shear-actuated flow characteristics of a fluid with a Newtonian model through a microchannel with parallel plates by invoking the reliance of a zeta or surface potential on slippage.The linearized Poisson-Boltzmann and momentum equations are solved analytically to obtain the explicit expression of the electrical potential induced in the electrical double layer(EDL),the flow velocity field,and the volumetric flow rate for an extensive span of parameters.The velocity field proximal to the microchannel wall is observed to enhance by an apparent zeta potential,and is further escalated for a thinner EDL and an oscillating electric field with a higher amplitude.However,near the core region of the microchannel,the flow velocity becomes invariant with the EDL thickness.The result shows that the lower wall velocity contributes to the flow velocity along with the electroosmotic body force and the impact of the velocity of the wall underneath diminishes proximal to the upper wall.Moreover,the volumetric flow rate increases when the thickness of the EDL decreases,owing to the influence of the wall slip.However,for thinner EDLs and medium and higher oscillating Reynolds numbers,the volumetric flow rate varies non-monotonously,correlative to the slip-free and slip cases.展开更多
A numerical analysis of the steady and pulsatile, macromolecular(such as low density lipopotein (LDL), Albumin) transport in T-bifurcation was proposed. The influence of Reynolds number and mass flow ratio etc. parame...A numerical analysis of the steady and pulsatile, macromolecular(such as low density lipopotein (LDL), Albumin) transport in T-bifurcation was proposed. The influence of Reynolds number and mass flow ratio etc. parameters on the velocity field and mass transport were calculated. The computational results predict that the blood flow factors affect the macromolecular distribution and the transport across the wall, it shows that hemodynamic play an important role in the process of atherosclerosis. The LDL and Albumin concentration on the wall varies most greatly in flow bifurcation area where the wall shear stress varies greatly at the branching vessel and the atherosclerosis often appears there.展开更多
In this paper, the analytic solution of the dynamical equation of the pulsatile flow in a rigid round tube under the low-frequency varying magnetic field is obtained. The velocity distribution and the flow impedance a...In this paper, the analytic solution of the dynamical equation of the pulsatile flow in a rigid round tube under the low-frequency varying magnetic field is obtained. The velocity distribution and the flow impedance are calculated. The results of e valuable for understanding the influence of low-frequency varying magnetic field on hemodynamics and its clinical application.展开更多
This study presents the effect of the magnetic field with constant intensity on the pulsatile flow through a rigid tube. Basing on the experimental results, the influence of the magnetic field on the blood viscosity i...This study presents the effect of the magnetic field with constant intensity on the pulsatile flow through a rigid tube. Basing on the experimental results, the influence of the magnetic field on the blood viscosity is considered The analytic solution of the pulsatile flow through a rigid tube under constant magnetic field intensitier and the effect of the magnetic field on the velocity distribution, flow and impedance in a rigid tube are given. this investigation is valuable for understanding the influence of the magnetic field on the blood circulation.展开更多
文摘This paper represents a detailed and systematic review of one of the most ongoing applications of computational fluid dynamics(CFD)in biomedical applications.Beyond its various engineering applications,CFD has started to establish a presence in the biomedical field.Cardiac abnormality,a familiar health issue,is an essential point of investigation by research analysts.Diagnostic modalities provide cardiovascular structural information but give insufficient information about the hemodynamics of blood.The study of hemodynamic parameters can be a potential measure for determining cardiovascular abnormalities.Numerous studies have explored the rheological behavior of blood experimentally and numerically.This paper provides insight into how researchers have incorporated the pulsatile nature of the blood experimentally,numerically,or through various simulations over the years.It focuses on how machine learning platforms derive outputs based on mass and momentum conservation to predict the velocity and pressure profile,analyzing various cardiac diseases for clinical applications.This will pave the way toward responsive AI in cardiac healthcare,improving productivity and quality in the healthcare industry.The paper shows how CFD is a vital tool for efficiently studying the flow in arteries.The review indicates this biomedical simulation and its applications in healthcare using machine learning and AI.Developing AI-based CFD models can impact society and foster the advancement towards responsive AI.
基金Weifang Fundamental Research Projects,No.WFWSJK-2023-052.
文摘BACKGROUND Pituitary stalk interruption syndrome(PSIS)is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes.It is characterized by a deficiency in anterior pituitary hormones,such as growth hormone,gonadotropins,and thyroid hormones.Due to the syndrome's rarity and nonspecific manifestations,there is a lack of standardized treatment strategies.Consequently,early diagnosis through imaging and on-time intervention are crucial for improving patients’outcomes.CASE SUMMARY A 30-year-old man presented with absent secondary sexual characteristics and azoospermia.Laboratory evaluation revealed a deficiency in gonadotropins,while thyroid function was mostly within normal ranges.Magnetic resonance imaging of the pituitary gland showed pituitary stalk agenesis,hypoplasia of the anterior pituitary,and ectopic posterior pituitary,leading to the diagnosis of PSIS.Initially,the patient underwent 6 mo of gonadotropin therapy without significant changes in hormone levels and secondary sexual characteristics.Pulsatile gonadotropin-releasing hormone therapy was then administered,resulting in the detection of sperm in the semen analysis within 3 mo.After 6 mo,routine semen tests showed normal semen quality.The couple faced challenges in conceiving due to abstinence and underwent three cycles of artificial insemination,which was unsuccessful.They also attempted in vitro fertilization,but unfortunately,the woman experienced a miscarriage 10 wk after the embryo transfer.CONCLUSION Early detection,accurate diagnosis,and timely treatment are crucial in improving the quality of life and fertility of PSIS patients.
基金This study was partly funded by the National Natural Science Foundation of China(Grant No.11602007,91430215,11572014)BJUT Foundation Fund(Grant No.015000514316007)+1 种基金Key research and development program(2016YFC0103201,2017YFC0111104)New Talent(015000514118002).
文摘Although pulsatile ECMO,as novel kinds of ECMO,has been attracted more and more attention,the differences of the hemodynamic effects of the pulsatile ECMO on the aorta,the cerebral perfusion,and left ventricular work were still under-investigated.The aim of this study was to clarify the hemodynamic differences of the cardiovascular system between the pulsatile and non-pulsatile VA ECMO.In this study,three ECMO support modes,named as“constant flow mode”,“co-pulse mode”and“counter pulse mode”,were designed.The computational fluid dynamics(CFD)study was carried out.The distribution of the oxygenated blood,the blood velocity vector,the oscillatory shear index(OSI),the relative residence time(RRT),the left ventricular external work(EW),the equivalent left ventricular afterload(EAL)and the energy loss of cardiovascular system(EL)were calculated to compare the hemodynamic differences.The simulation results demonstrate that the oxygenated blood under co-pulse mode was easier to perfuse into the three braches vessels than that under both other modes.In addition,the ECMO under counter pulse mode could also achieve lowest RRT(constant flow mode 220 vs.co-pulse mode 132 vs.counter pulse mode 93).Similarly,the ECMO under counter pulse mode could significantly reduce the left ventricular external work(co-pulse mode 1.51 w vs.constant flow mode 1.44 w and counter pulse mode 1.30 w),left ventricular afterload(constant flow mode 1.03 mmHg·s/ml vs.co-pulse mode 1.67 mmHg·s/ml vs.counter pulse mode 0.82 mmHg·s/ml)and energy loss of arterial system(constant flow mode 0.18 w vs.co-pulse mode 0.50 w vs.counter pulse mode 0.16 w).In short,the ECMO under counter pulse mode could have advantages to the left ventricular unloading.In contrast,the ECMO under co-pulse mode has more benefit to cerebral oxygen perfusion.
文摘Both pulsatile gonadotropin-releasing hormone （GnRH） infusion and combined gonadotropin therapy （human chorionic gonadotropin and human menopausal gonadotropin [HCG/HMG]） are effective to induce spermatogenesis in male patients with congenital hypogonadotropic hypogonadism （CH H）. However, evidence is lacking as to which treatment strategy is better. This retrospective cohort study included 202 patients with CHH： twenty had received pulsatile GnRH and 182 had received HCG/HMG. Patients had received therapy for at least 12 months. The total follow-up time was 15.6 ± 5.0 months （range： 12-27 months） for the GnRH group and 28.7 ± 13.0 months （range： 12-66 months） for the HCG/HMG group. The median time to first sperm appearance was 6 months （95% confidence interval [CI]： 1.6-10.4） in the GnRH group versus 18 months （95% Ch 16.4-20.0） in the HCG/HMG group （P〈 0.001）. The median time to achieve sperm concentrations 〉5 x 106 m1-1 was 14 months （95% Ch 5.8-22.2） in the GnRH group versus 27 months （95% Ch 18.9-35.1） in the HCG/HMG group （P 〈 0.001）, and the median time to concentrations 〉10 x 106 m1-1 was 18 months （95% Ch 10.0-26.0） in the GnRH group versus 39 months （95% CI unknown） in the HCG/HMG group. Compared to the GnRH group, the HCG/HMG group required longer treatment periods to achieve testicular sizes of 〉4 ml, 〉8 ml, 〉12 ml, and 〉16 ml. Sperm motility （a ＋ b ＋ c percentage） evaluated in semen samples with concentrations 〉1 × 106 ml-1 was 43.7% ± 20.4% （16 samples） in the GnRH group versus 43.2% ± 18.1% （153 samples） in the HCG/HMG group （P= 0.921）. Notably, during follow-up, the GnRH group had lower serum testosterone levels than the HCG/HMG group （8.3 ±4.6 vs 16.2 ± 8.2 nmol 1-1, P 〈 0.001）. Our study found that pulsatile GnRH therapy was associated with earlier spermatogenesis and larger testicular size compared to combined gonadotropin therapy. Additional prospective randomized studies would be required to confirm these findings.
基金This study was supported by the National Natural Science Foundation of China(Grants 11602053 and 51576033)the Fundamental Research Funds for the Central Universities(Grant DUT18JC23).
文摘This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental findings.The maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm dome.There is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance increased.These results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.
文摘The effects of the renal artery stenosis （RAS） on the blood flow and vessel walls are investigated. The pulsatile blood flow through an anatomically realistic model of the abdominal aorta and renal arteries reconstructed from CT-scan images is simulated, which incorporates the fluid-structure interaction （FSI）. In addition to the investigation of the RAS effects on the wall shear stress and the displacement of the vessel wall, it is determined that the RAS leads to decrease in the renal mass flow. This may cause the activation of the renin-angiotension system and results in severe hypertension.
基金supported by the Medical Science and Technology Project of Zhejiang Province(No.2019KY584)Traditional Chinese Medicine Science and Technology Project of Zhejiang Province(No.2023ZL648).
文摘Objective To investigate the etiology,clinical characteristics,diagnosis,and treatment strategies and efficacy of pulsatile tinnitus(PT)caused by vascular anatomy abnormality.Methods The clinical data of 45 patients with PT in our hospital from 2012 to 2019 were collected and retrospectively analyzed.Results All 45 patients had vascular anatomical abnormalities.The patients were divided into 10 categories according to the different locations of vascular abnormalities:sigmoid sinus diverticulum(SSD),sigmoid sinus wall dehiscence(SSWD),SSWD with high jugular bulb,pure dilated mastoid emissary vein,aberrant internal carotid artery(ICA)in the middle ear,transverse-sigmoid sinus(TSS)transition stenosis,TSS transition stenosis with SSD,persistent occipital sinus stenosis,petrous segment stenosis of ICA,and dural arteriovenous fistula.All patients complained of PT synchronous with heartbeat rhythm.Endovascular interventional therapy and extravascular open surgery were used according to the location of the vascular lesions.Tinnitus disappeared in 41 patients,was significantly relieved in 3 patients,and was unchanged in 1 patient postoperatively.Except for one patient with transient headache postoperatively,no obvious complications occurred.Conclusion PT caused by vascular anatomy abnormalities can be identified by detailed medical history and physical and imaging examination.PT can be relieved or even completely alleviated after appropriate surgical treatments.
文摘Pulsatile gonadotropin-releasing hormone （GnRH） may induce spermatogenesis in most patients with congenital hypogonadotropic hypogonadism （CHH） by stimulating gonadotropin production, while the predictors for a pituitary response to pulsatile GnRH therapy were rarely investigated. Therefore, the aim of our study is to investigate predictors of the pituitary response to pulsatile GnRH therapy. This retrospective cohort study included 82 CHH patients who received subcutaneous pulsatile GnRH therapy for at least 1 month. Patients were categorized into poor or normal luteinizing hormone （LH） response subgroups according to their LH level （LH 〈2 IU 1-1 or LH P_2 IU 1-1） 1 month into pulsatile GnRH therapy. Gonadotropin and testosterone levels, testicular size, and sperm count were compared between the two subgroups before and after GnRH therapy. Among all patients, LH increased from 0.4±0.5 IUI^-1 to 7.5±4.4 IUI^-1 and follicle-stimulating hormone （FSH） increased from 1.1±0.9 IUI^-1 to 8.8±5.3 IU 1-1. A Cox regression analysis showed that basal testosterone level （6 = 0.252, P = 0.029） and triptorelin-stimulated FSH60min（13 = 0.518, P = 0.01） were two favorable predictors for pituitary response to GnRH therapy. Nine patients （9/82, 11.0%） with low LH response to GnRH therapy were classified into the poor LH response subgroup. After pulsatile GnRH therapy, total serum testosterone level was 39± 28 ng dl^-1 versus 248±158 ng d1^-1 （P=0.001）, and testicular size was 4.0±3.1 ml versus 7.9±4.5 ml （P= 0.005） in the poor and normal LH response subgroups, respectively. It is concluded that higher levels of triptorelin-stimulated FSH60min. and basal total serum testosterone are favorable predictors of pituitary LH response to GnRH therapy.
基金The Beijing Scholar 2015and the National Natural Science Foundation of China,No.61931013,No.81701644,and No.61801311.
文摘BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures in PT patients with multiple causes after stenting for ipsilateral transverse sinus stenosis(TSS)have not been previously reported.We report such a case and present postoperative computed tomography venography(CTV)follow-up findings to demonstrate the decreased sigmoid sinus diverticulum and bone remodeling.CASE SUMMARY A 45-year-old man suffered from left-sided PT for 15 years that was occasionally accompanied by headache and dizziness.Pre-operative CTV revealed left-sided sigmoid sinus wall anomalies(SSWAs),TSS,outflow dominance,large posterior condylar emissary vein,and an empty sella turcica.A cerebrospinal fluid pressure of 270 mmH2O was further detected.The sound disappeared immediately after stenting for ipsilateral TSS,with no recurrence during 2 years of follow-up.After the procedure,the patient underwent four consecutive CTV examinations.The diverticulum decreased 6 mo after the procedure with new bone remodeling.The density of the remodeled bone was further increased 1 year later,and a hardened edge was formed 2 years later.CONCLUSION PT associated with SSWAs,TSS,and idiopathic intracranial hypertension can be cured by stenting for TSS alone.And bone remodeling around SSWAs is a more significant finding.
基金supported by the Natural Science Foundation of Liaoning(2020-MS-092).
文摘Lattice sandwich structures are broadly used in aerospace,navigation,and high-speed rail engineering.In engineering practice,the airflow outside the vehicle or aircraft always exhibits the pulsatile property,which makes the elastic structural components and the external airflow a parametric excitation system.In this paper,the parametric vibration stability analysis and dynamic characteristics of a lattice sandwich plate interacting with the pulsatile external airflow are studied.The equation of motion is derived using Hamilton’s principle and discretized using the assumed mode method.The linear potential flow theory is applied to derive the perturbation aerodynamic pressure.The stability of the system is analyzed using the Floquet theory and validated by numerical simulations.The effects of design parameters of the lattice sandwich plate on the stability of the system are discussed.From the simulations and discussions,some practical principles for the optimal design of lattice sandwich structures in the aerodynamic environment are proposed.
文摘The aim of this study was to prepare pulsatile release tablets which provide different drug delayed-release time and realize personalized administration according to the needs of patients.Fused deposition modeling(FDM)3D printing technology was introduced into the field of pharmaceutics in this study,and the feasibility to prepare core-shell pulsatile release tablets was explored by combing 3D printing technology with the traditional manufacturing technology.The core of the pulsatile tablets was a commercial tablet obtained from the traditional technology,and the drug-free shell was prepared by the FDM 3D printing technology.Three kinds of tablet shells were designed using different parameters.Furthermore,the morphology,size,weight,hardness,and in vitro drug release of the 3D printed famotidine pusatile tablets were characterized and evaluated.The results showed that the 3D printed tablets appeared intact without any defects.Different parameters of outer shell affected the size,weight,hardness,and in vitro drug release of the tablets.The tablets achieved a personalized delayed release time varying from 5 to 7 h in vitro.In this way,a new method for preparing pulsatile release tablets and a new way for the personalized administration of pulsatile tablets were explored in this study.
基金Supported by National Natural Science Foundation of China,No.61931013 and No.61801311.
文摘BACKGROUND Pulsatile tinnitus(PT)is an annoying sound that can be eliminated with targeted treatment of the cause.However,the causes of PT have not been fully elucidated.CASE SUMMARY A 38-year-old woman with right-sided objective PT underwent preoperative computed tomography arteriography and venography(CTA/V).A 3.8 mm vine diploic vein(DV),which passed through the mastoid air cells posteriorly in a dehiscent canal and was continuous with the transverse-sigmoid sinus,was thought to be the causative finding.Four-dimensional flow magnetic resonance(4D flow MR)imaging showed that the blood in the DV flowed toward the transverse-sigmoid sinus.The closer the blood was to the transverse-sigmoid sinus,the higher the velocity.No vortex or turbulence was found in the DV or adjacent transverse sinus.The sound was eliminated immediately after ligation of the DV with no recurrence during a three-month follow-up.No flow signal of the DV was noted on postoperative 4D flow MR.CONCLUSION A DV may be a treatable cause of PT.CTA/V and 4D flow MR could be utilized to determine the morphological and hemodynamic characteristics of the DV.
基金financially supported by Babol Noshirvani University of Technology, Iran
文摘In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence,(ii) incomplete coalescence and(iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets(mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength,frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.
文摘In this paper, the pulsatile flow of blood through an inclined catheterized stenosed artery is analyzed. Perturbation method is used to solve the implicit system of partial differential equations with suitable boundary conditions. Various analytical expressions axial velocity, flow rate, wall shear stress and effective viscosity have been derived with the help of MATLAB for understanding the fluid flow phenomena. The combined effect of catheterization, body acceleration, slip and inclination has been seen by plotting the graph and observed that axial velocity and flow rate increases with the increase in body acceleration, inclination angle and slip velocity while axial velocity diminishes on increasing the catheter radius. Wall shear stress increases with the increase in catheter radius and body acceleration but presence of slip velocity reduces the wall shear stress. Effective viscosity diminishes on increasing body acceleration and inclination angle, whereas slightly augmented in non-inclined stenosed artery.
文摘A three-dimensional computational fluid dynamics (CFD) simulation of the physiological pulsatile blood flow in the human aortic arch and its three branches has been conducted by using commercial software StarCD. The blood flow, of a peak Reynolds number of 3289 and a Womersley parameter of 16.44, was simulated in a rigid aorta geometry that was built by computer aided design (CAD) reconstruction method based on autopsy data of a female adult. The purpose of this work is to further the understanding of the complex nature of aorta flow, therefore it mainly focuses on analysis of the spatial and temporal distributions of velocities and wall shear stresses. The results, illustrated by 3D visualization pictures and 2D graphs of the primary velocity profiles, wall shear stress and pressure distributions, as well as the secondary flow patterns, are in good agreement with those of other experimental and computational works. The distributions of pressure and wall shear stress support the correlation between high and low shear stresses and pressures and the atherosclerotic lesions.
基金Project supported by the National Natural Science Foundation of China(Nos.11172060 and11672065)
文摘The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts as a low-pass filter, and the biochemical signals are nonlinearly modulated by the pulsatile flows, which depend on the biochemical signal frequency, the flow signal frequency, and the biochemical signal transporting distance. It is concluded that, the transfer characteristics of the dynamic biochemical signals, which are transported in the time-varying flows, should be carefully considered for better loading biochemical signals on the cells cultured on the bottom of the microfluidic channel.
文摘The escalation of zeta potential by the influence of wall slip for the electrokinetically modulated flow through a microchannel motivates to consider the impact of hydrodynamic slippage upon the zeta or surface potential.The reported study undergoes an analytical exploration of the pulsatile electroosmosis and shear-actuated flow characteristics of a fluid with a Newtonian model through a microchannel with parallel plates by invoking the reliance of a zeta or surface potential on slippage.The linearized Poisson-Boltzmann and momentum equations are solved analytically to obtain the explicit expression of the electrical potential induced in the electrical double layer(EDL),the flow velocity field,and the volumetric flow rate for an extensive span of parameters.The velocity field proximal to the microchannel wall is observed to enhance by an apparent zeta potential,and is further escalated for a thinner EDL and an oscillating electric field with a higher amplitude.However,near the core region of the microchannel,the flow velocity becomes invariant with the EDL thickness.The result shows that the lower wall velocity contributes to the flow velocity along with the electroosmotic body force and the impact of the velocity of the wall underneath diminishes proximal to the upper wall.Moreover,the volumetric flow rate increases when the thickness of the EDL decreases,owing to the influence of the wall slip.However,for thinner EDLs and medium and higher oscillating Reynolds numbers,the volumetric flow rate varies non-monotonously,correlative to the slip-free and slip cases.
文摘A numerical analysis of the steady and pulsatile, macromolecular(such as low density lipopotein (LDL), Albumin) transport in T-bifurcation was proposed. The influence of Reynolds number and mass flow ratio etc. parameters on the velocity field and mass transport were calculated. The computational results predict that the blood flow factors affect the macromolecular distribution and the transport across the wall, it shows that hemodynamic play an important role in the process of atherosclerosis. The LDL and Albumin concentration on the wall varies most greatly in flow bifurcation area where the wall shear stress varies greatly at the branching vessel and the atherosclerosis often appears there.
文摘In this paper, the analytic solution of the dynamical equation of the pulsatile flow in a rigid round tube under the low-frequency varying magnetic field is obtained. The velocity distribution and the flow impedance are calculated. The results of e valuable for understanding the influence of low-frequency varying magnetic field on hemodynamics and its clinical application.
基金Project supported by the National Natural Science Foundation of China
文摘This study presents the effect of the magnetic field with constant intensity on the pulsatile flow through a rigid tube. Basing on the experimental results, the influence of the magnetic field on the blood viscosity is considered The analytic solution of the pulsatile flow through a rigid tube under constant magnetic field intensitier and the effect of the magnetic field on the velocity distribution, flow and impedance in a rigid tube are given. this investigation is valuable for understanding the influence of the magnetic field on the blood circulation.
