Lost circulation of drilling fluid is one of the most common and costly problems in drilling operations.This highlights the importance of wellbore strengthening treatment sthat can utilize lost circulation materials(L...Lost circulation of drilling fluid is one of the most common and costly problems in drilling operations.This highlights the importance of wellbore strengthening treatment sthat can utilize lost circulation materials(LCMs)to seal fractures associated with the wellbore.In this work,a numerical model accounting for the deformation of surrounding rock,fluid flow in the fracture,fracture propagation,and the transport of LCMs is presented to investigate the wellbore strengthening,from the fracture initiation to the fracture arrest,due to plugs formed by LCMs.The equations governing the rock deformation and fluid flow are solved by the dual boundary element method and the finite volume method,respectively.The transport of LCMs is solved based on an empirical constitutive model in suspension flow,and several characteristic quantities are derived by dimensional analysis.It is found that two dimensionless parameters,dimensionless toughness and normalized initial particle concentration,control the migration of LCM particles.The numerical results show that the dimensionless toughness influences the entrance and bridging of LCMs while the initial concentration controls the location of the particle bridging.When the initial concentration is larger than 0.8,the particle bridging tends to occur near the fracture entry.Conversely,when the initial concentration is less than 0.8,the particle bridging occurs near the fracture tip.This work provides an effective tool to predict the LCM transport and plugging in the wellbore strengthening process.展开更多
As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok...As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok’s Wat Po temple lies a quieter,gentler form of diplomacy—one that happens through kneading hands,respectful bows,and an ancient art passed down across generations.At the Wat Po Thai Traditional Medical School,headmaster Serat Tangtrongchitr sees Thai massage not only as a healing craft,but as a cultural bridge—one that connects people across borders,languages,and belief systems.“We don’t just teach massage,”Serat said,his voice calm but assured.“We teach a way of life.And when people from other cultures learn this with us—Chinese students included—they come to understand not just the techniques,but the heart of Thai culture.”展开更多
BACKGROUND Patients diagnosed with esophageal mucosal bridges often experience symptoms such as chest pain and dysphagia,which pose considerable challenges for endo-scopic surgical interventions.CASE SUMMARY We presen...BACKGROUND Patients diagnosed with esophageal mucosal bridges often experience symptoms such as chest pain and dysphagia,which pose considerable challenges for endo-scopic surgical interventions.CASE SUMMARY We present a case involving early-stage esophageal cancer discovered in a resting room,notable for the rare manifestation of esophageal mucosal bridging.Following a comprehensive multidisciplinary discussion and the development of a treatment strategy,we proceeded with endoscopic submucosal dissection for the patient.During the procedure,we encountered operational challenges due to the presence of a diverticulum and a partial absence of the muscularis propria.To facilitate the retraction of a portion of the resected specimen,we utilized dental floss.Ultimately,we successfully excised the entire lesion.After a three-day period of fasting with a water-only diet,subsequent iodine water cholan-giography did not indicate any perforations,and the patient was advised to transition to a liquid diet.The patient was discharged five days post-operation.A follow-up endoscopy conducted three months later revealed scar-like changes in the mid-esophagus,with the patient reporting no significant discomfort.CONCLUSION In summary,although esophageal mucosal bridges are rarely documented,they should be considered in the differential diagnosis of mechanical dysphagia.Furthermore,endoscopic therapy represents a feasible approach for their mana-gement.展开更多
The Emerging Markets and Developing Countries Forum on Bridging the AI Divide and Opening Ceremony of AIM Global CoE were held on July 27 in Minhang district,Shanghai.The event was hosted by AIM Global CoE,and co-orga...The Emerging Markets and Developing Countries Forum on Bridging the AI Divide and Opening Ceremony of AIM Global CoE were held on July 27 in Minhang district,Shanghai.The event was hosted by AIM Global CoE,and co-organized by Shanghai Artificial Intelligence Research Institute(SAIRI),Shanghai Technology Innovation Center,Shanghai Grand Neobay Investment Development Group,and Organizing Committee of AI Journey Conference.Asian Association of Business Incubation(AABI)and SAIRI served as the international partners.展开更多
Traditional Chinese medicine (TCM) with its millenniaold wisdom rooted in the principles of holistic Yin-Yang balance and “Bianzheng Lunzhi”[辨证论治, Zhenghou(证候) differentiation and treatment], has long offered ...Traditional Chinese medicine (TCM) with its millenniaold wisdom rooted in the principles of holistic Yin-Yang balance and “Bianzheng Lunzhi”[辨证论治, Zhenghou(证候) differentiation and treatment], has long offered a unique lens to understand human health and disease.However, the modern scientific interpretation of TCM remains at the stage of “knowing that it works, but not knowing why it works”.展开更多
Blinatumomab has demonstrated efficacy in B-cell acute lymphoblastic leukemia(B-ALL),achieving a measurable residual disease(MRD)negativity rate of 78%(1).Its addition to consolidation chemotherapy or administration p...Blinatumomab has demonstrated efficacy in B-cell acute lymphoblastic leukemia(B-ALL),achieving a measurable residual disease(MRD)negativity rate of 78%(1).Its addition to consolidation chemotherapy or administration prior to allogeneic hematopoietic stem cell transplantation(allo-HSCT)has been shown to significantly improve overall survival(OS)and relapse-free survival(RFS)in adult B-ALL patients(2,3).展开更多
Biocatalysis with nicotinamide adenine dinucleotide phosphate(NADP)-dependent oxidoreductases faces a challenge in improving the efficiency of the costly cofactor utilization.Although enzyme fusion can offer cofactor ...Biocatalysis with nicotinamide adenine dinucleotide phosphate(NADP)-dependent oxidoreductases faces a challenge in improving the efficiency of the costly cofactor utilization.Although enzyme fusion can offer cofactor regeneration,the high-volume input and limited cofactor recyclability still make the enzymatic processes unsustainable.Therefore,it is of great significance to reduce cofactor input in a fusion enzyme(FuE)system,but no successful practice has been reported.Herein,we design a decapeptide bridge,RRRQRRRARR(R10),with high affinity for NADPH to construct fusion oxidoreductases(phenylacetone monooxygenase and phosphite dehydrogenase)for ester synthesis and NADP recycling.The peptide bridge enables electrostatic cofactor channeling that transports NADPH/NADP^(+)across the peptide between the enzymes’NADP-binding pockets,so the fusion enzyme(FuE-R10)presents 2.1-folds and 2.0-folds higher conversions than mixed free enzymes and a flexible linker(GGGGSGGGGS)-fused enzyme,respectively,at NADPH/FuE of 0.1.The fusion enzyme,FuE-R5,bridged by a half-shortened linker,is proved more effective in facilitating cofactor channeling;compared to the mixed free enzymes,FuE-R5 exhibits two orders of magnitude reduction of NADPH input in ester synthesis.The work has thus demonstrated the potential of the cofactor bridging strategy in the development of sustainable cofactor-dependent cascade biocatalysis.展开更多
We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in...We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.展开更多
In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the rol...In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ignored.Herein,we studied industrially important ternary composites,polypropylene(PP)/ethylene-octene copolymer(a polyolefin elastomer,POE)/talc systems,and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc particles.It is found that talc fillers concentrate in the PP phase using the“blend first”protocol,while more talc particles are located at the interface of PP and POE phases using the“filler first”protocol.Changing the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the“filler first”protocol.The linear rheology behavior indicates that besides the“volume exclusion effect”,the talc-POE hybrid network can further contribute to the reinforcement effect.Meanwhile,the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear,in contrast to the un-recoverable structures in the PP/talc binary composites.The correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers.展开更多
The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transitio...The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is an aggressive malignant neoplasm that requires liver transplantation(LT).Despite patients with HCC being prioritized by most organ allocation systems worldwide,they still hav...BACKGROUND Hepatocellular carcinoma(HCC)is an aggressive malignant neoplasm that requires liver transplantation(LT).Despite patients with HCC being prioritized by most organ allocation systems worldwide,they still have to wait for long periods.Locoregional therapies(LRTs)are employed as bridging therapies in patients with HCC awaiting LT.Although largely used in the past,transarterial embolization(TAE)has been replaced by transarterial chemoembolization(TACE).However,the superiority of TACE over TAE has not been consistently shown in the literature.AIM To compare the outcomes of TACE and TAE in patients with HCC awaiting LT.METHODS All consecutive patients with HCC awaiting LT between 2011 and 2020 at a single center were included.All patients underwent LRT with either TACE or TAE.Some patients also underwent percutaneous ethanol injection(PEI),concom-itantly or in different treatment sessions.The choice of LRT for each HCC nodule was determined by a multidisciplinary consensus.The primary outcome was waitlist dropout due to tumor progression,and the secondary outcome was the occurrence of adverse events.In the subset of patients who underwent LT,complete pathological response and post-transplant recurrence-free survival were also assessed.RESULTS Twelve(18.5%)patients in the TACE group(only TACE and TACE+PEI;n=65)and 3(7.9%)patients in the TAE group(only TAE and TAE+PEI;n=38)dropped out of the waitlist due to tumor progression(P log-rank test=0.29).Adverse events occurred in 8(12.3%)and 2(5.3%)patients in the TACE and TAE groups,respectively(P=0.316).Forty-eight(73.8%)of the 65 patients in the TACE group and 29(76.3%)of the 38 patients in the TAE group underwent LT(P=0.818).Among these patients,complete pathological response was detected in 7(14.6%)and 9(31%)patients in the TACE and TAE groups,respectively(P=0.145).Post-LT,HCC recurred in 9(18.8%)and 4(13.8%)patients in the TACE and TAE groups,respectively(P=0.756).Posttransplant recurrence-free survival was similar between the groups(P log-rank test=0.71).CONCLUSION Dropout rates and posttransplant recurrence-free survival of TAE were similar to those of TACE in patients with HCC.Our study reinforces the hypothesis that TACE is not superior to TAE as a bridging therapy to LT in patients with HCC.展开更多
Objective:To analyze the clinical effect of a simple egg membrane patch bridging method in repairing tympanic membrane perforation.Methods:A total of 93 tympanic membrane perforation patients admitted to the hospital ...Objective:To analyze the clinical effect of a simple egg membrane patch bridging method in repairing tympanic membrane perforation.Methods:A total of 93 tympanic membrane perforation patients admitted to the hospital between September 2022 and October 2023 were selected and divided into two groups according to the random number table method.The control group implemented the conventional treatment(n=46 cases),and the patch group adopted the simple egg membrane patch bridging method(n=47 cases).The healing rate of the tympanic membrane,the air-bone gap,the air conduction hearing threshold,the dry ear rate,and the incidence of complications in both groups were compared before and after treatment.Results:The healing rate of the tympanic membrane in the patch group was significantly higher than that of the control group(95.75%vs.76.09%),with P<0.05;there was no difference in the air-bone gap and air conduction hearing threshold levels between the two groups before treatment(P>0.05),and the hearing indexes of the patch group were significantly lower than those of the control group 3 months after treatment(P<0.05);the dry ear rate in the patch group was significantly higher than that of the control group after treatment(85.11%vs.67.39%),and the total incidence of complications was also significantly lower than that of the control group(6.38%vs.21.74%),with P<0.05.Conclusion:The simple egg membrane patch bridging method is effective in repairing tympanic membrane perforation,which can effectively improve patients’hearing levels and reduce the occurrence of post-treatment complications.Thus,it is worth popularizing and applying in the clinic.展开更多
AIM:To analyze whether high-intensity focused ultrasound(HIFU) ablation is an effective bridging therapy for patients with hepatocellular carcinoma(HCC).METHODS:From January 2007 to December 2010,49 consecutive HCC pa...AIM:To analyze whether high-intensity focused ultrasound(HIFU) ablation is an effective bridging therapy for patients with hepatocellular carcinoma(HCC).METHODS:From January 2007 to December 2010,49 consecutive HCC patients were listed for liver transplantation(UCSF criteria).The median waiting time for transplantation was 9.5 mo.Twenty-nine patients received transarterial chemoembolization(TACE) as a bringing therapy and 16 patients received no treatment before transplantation.Five patients received HIFU ablation as a bridging therapy.Another five patients with the same tumor staging(within the UCSF criteria) who received HIFU ablation but not on the transplant list were included for comparison.Patients were comparable in terms of Child-Pugh and model for end-stage liver disease scores,tumor size and number,and cause of cirrhosis.RESULTS:The HIFU group and TACE group showed no difference in terms of tumor size and tumor number.One patient in the HIFU group and no patient in the TACE group had gross ascites.The median hospital stay was 1 d(range,1-21 d) in the TACE group and two days(range,1-9 d) in the HIFU group(P < 0.000).No HIFU-related complication occurred.In the HIFU group,nine patients(90%) had complete response and one patient(10%) had partial response to the treatment.In the TACE group,only one patient(3%) had response to the treatment while 14 patients(48%) had stable disease and 14 patients(48%) had progressive disease(P = 0.00).Seven patients in the TACE group and no patient in the HIFU group dropped out from the transplant waiting list(P = 0.559).CONCLUSION:HIFU ablation is safe and effective in the treatment of HCC for patients with advanced cirrhosis.It may reduce the drop-out rate of liver transplant candidate.展开更多
Several therapeutic procedures have been proposed as bridging treatments for patients with hepatocellular carcinoma(HCC)awaiting liver transplantation(LT).The most used treatments include transarterial chemoembolizati...Several therapeutic procedures have been proposed as bridging treatments for patients with hepatocellular carcinoma(HCC)awaiting liver transplantation(LT).The most used treatments include transarterial chemoembolization and radiofrequency ablation.Surgical resection has also been successfully used as a bridging procedure,and LT should be considered a rescue treatment in patients with previous HCC resection who experience tumor recurrence or post-treatment severe decompensation of liver function.The aims of bridging treatments include decreasing the waiting list dropout rate before transplantation,reducing HCC recurrence after transplantation,and improving post-transplant overall survival.To date,no data from prospective randomized studies are available;however,for HCC patients listed for LT within the Milan criteria,prolonging the waiting time over 6-12 mo is a risk factor for tumor spread.Bridging treatments are useful in containing tumor progression and decreasing dropout.Furthermore,the response to pre-LT treatments may represent a surrogate marker of tumor biological aggressiveness and could therefore be evaluated to prioritize HCC candidates for LT.Lastly,although a definitive conclusion can not be reached,the experiences reported to date suggest a positive impact of these treatments on both tumor recurrence and post-transplant patient survival.Advanced HCC may be downstaged to achieve and maintain the current conventional criteria for inclusion in the waiting list for LT.Recent studies have demonstrated that successfully downstaged patients can achieve a 5-year survival rate comparable to that of patients meeting the conventional criteria without requiring downstaging.展开更多
BACKGROUND Prospective study of 200 patients with hepatocellular carcinoma(HCC)that underwent liver transplant(LT)after drug-eluting beads transarterial chemoembolization(DEB-TACE)for downstaging versus bridging.Overa...BACKGROUND Prospective study of 200 patients with hepatocellular carcinoma(HCC)that underwent liver transplant(LT)after drug-eluting beads transarterial chemoembolization(DEB-TACE)for downstaging versus bridging.Overall survival and tumor recurrence rates were calculated,eligibility for LT,time on the waiting list and radiological response were compared.After TACE,only patients within Milan Criteria(MC)were transplanted.More patients underwent LT in bridging group.Five-year post-transplant overall survival,recurrence-free survival has no difference between the groups.Complete response was observed more frequently in bridging group.Patients in DS group can achieve posttransplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.AIM To determine long-term outcomes of patients with HCC that underwent LT after DEB-TACE for downstaging vs bridging.METHODS Prospective cohort study of 200 patients included from April 2011 through June 2014.Bridging group included patients within MC.Downstaging group(out of MC)was divided in 5 subgroups(G1 to G5).Total tumor diameter was≤8 cm for G1,2,3,4(n=42)and was>8 cm for G5(n=22).Downstaging(n=64)and bridging(n=136)populations were not significantly different.Overall survival and tumor recurrence rates were calculated by the Kaplan-Meier method.Additionally,eligibility for LT,time on the waiting list until LT and radiological response were compared.RESULTS After TACE,only patients within MC were transplanted.More patients underwent LT in bridging group 65.9%(P=0.001).Downstaging population presented:higher number of nodules 2.81(P=0.001);larger total tumor diameter 8.09(P=0.001);multifocal HCC 78%(P=0.001);more post-transplantation recurrence 25%(P=0.02).Patients with maximal tumor diameter up to 7.05 cm were more likely to receive LT(P=0.005).Median time on the waiting list was significantly longer in downstaging group 10.6 mo(P=0.028).Five-year posttransplant overall survival was 73.5%in downstaging and 72.3%bridging groups(P=0.31),and recurrence-free survival was 62.1%in downstaging and 74.8%bridging groups(P=0.93).Radiological response:complete response was observed more frequently in bridging group(P=0.004).CONCLUSION Tumors initially exceeding the MC down-staged after DEB-TACE,can achieve post-transplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.展开更多
High-intensity focused ultrasound(HIFU)is a noninvasive modality that uses an extracorporeal source of focused ultrasound energy.This technique was introduced by Lynn et al and is able to induce coagulative necrosis i...High-intensity focused ultrasound(HIFU)is a noninvasive modality that uses an extracorporeal source of focused ultrasound energy.This technique was introduced by Lynn et al and is able to induce coagulative necrosis in selected tissues without damaging adjacent structures.Although HIFU has been studied for 50years,recent technological developments now allow its use for tumours of the liver,prostate and other sites.In liver disease,HIFU has been used to treat unresectable,advanced stages of hepatocellular carcinoma(HCC)and liver metastases.Hepatocellular carcinoma is a serious health problem worldwide and is endemic in some areas because of its association with hepatitis B and C viruses(in 20%of cases).Liver transplantation(LT)has become one of the best treatments available because it removes both the tumour and the underlying liver disease such as cirrhosis(which is present in approximately 80%of cases).The prerequisite for longterm transplant success depends on tumour load and strict selection criteria regarding the size and number of tumour nodules.The need to obtain the optimal benefit from the limited number of organs available has prompted strict selection criteria limited to only those patients with early HCC who have a better long-term outcome after LT.The so-called"bridging therapy"has the aim of controlling disease burden for patients who are on the organ transplant waiting list.Amongst various treatment options,transarterial chemoembolisation and radiofrequency ablation are the most popular treatment choices.Recently,Cheung et al demonstrated that HIFU ablation is a safe and effective method for the treatment of HCC patients with advanced cirrhosis as a bridging therapy and that it reduced the dropout rate from the liver transplant waiting list.In this commentary,we discuss the current value of HIFU in the treatment of liver disease,including its value as a bridging therapy,and examine the potential advantages of other therapeutic strategies.展开更多
Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation untreated.Degrada...Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation untreated.Degradable materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix stimulation.Despite the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not optimized.The current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular product.It is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and diverters.Mathematical modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage optimization.In this work,we develop a numerical model to study fiber dynamics in fluid flow.We employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected spheres.The discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous interactions.The focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in carbonates.The trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental observations.The present numerical investigation reveals that the bridging capability of the fiber–fluid system can be enhanced by increasing the fiber loading,selecting fibers with higher stiffness,reducing the injection flow rate,reducing the suspending fluid viscosity or increasing the attractive cohesive forces among fibers by using sticky fibers.展开更多
Spinal cord injury （SCI） damages not only the gray matter neurons, but also the white matter axonal tracts that carry signals to and from the brain, re- suiting in permanent loss of function below injury. Neural ste...Spinal cord injury （SCI） damages not only the gray matter neurons, but also the white matter axonal tracts that carry signals to and from the brain, re- suiting in permanent loss of function below injury. Neural stem cells （NSCs） have high therapeutic potential for reconstruction of the injured spinal cord since they can potentially fnrm neuronal relays to bridge functional con-nectivity between separated spinal cord segments. This requires host axonal regeneration into and connectivity with donor neurons, and axonal growth and connectivity of donor neurons to host central nervous system （CNS） circuitry. In this mini-review, we will discuss key studies that explore novel neuronal relay formation by grafting NSCs in models of SCI, with emphasis on long-distance axonal growth and connectivity of NSCs grafted into in-jured spinal cord.展开更多
We present a case of a 71-year-old male who hadchest symptoms at rest and during effort. He had felt chest oppression during effort for 1 year,and his chest symptoms had recently worsened. One month before admission h...We present a case of a 71-year-old male who hadchest symptoms at rest and during effort. He had felt chest oppression during effort for 1 year,and his chest symptoms had recently worsened. One month before admission he felt chest squeezing at rest in the early morning. He presented at our institution to evaluate his chest symptoms. Electrocardiography and echocardiography failed to show any specific changes. Because of the possibility that his chest symptoms were due to myocardial ischemia,he was admitted to our institution for coronary angiography(CAG). An initial CAG showed mild atherosclerotic changes in the proximal segment of the left anterior descending coronary artery(LAD) and mid-segment of the left circumflex coronary artery. Subsequent spasm provocation testing using acetylcholine revealed a bilateral coronary vasospasm,which was relieved after the intracoronary infusion of nitroglycerin. Finally,a CAG showed myocardial bridging(MB) of the mid-distal segments of the LAD. Fractional flow reserve using the intravenous administration of adenosine triphosphate was positive at 0.77,which jumped up to 0.90 through the myocardial bridging segments when the pressure wire was pulled back. Thus,coronary vasospasm and MB might have contributed to his chest symptoms at rest and during effort. Interventional cardiologists should consider the presence of MB as a potential cause of myocardial ischemia.展开更多
BACKGROUND：Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain ...BACKGROUND：Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain unclear.OBJECTIVE：To explore the feasibility and advantages of chitosan tube bridging autologous nerve segments for repairing 12-mm sciatic nerve defects in rats.DESIGN,TIME AND SETTING：A randomized,controlled,animal study using nerve tissue engineering was performed at the Animal Laboratory and Laboratory of Histology and Embryology,Liaoning Medical University from June 2008 to March 2009.MATERIALS：Chitosan powder was purchased from Jinan Haidebei Marine Bioengineering,China.METHODS：A sciatic nerve segment of approximately 8 mm was excised from the posterior margin of the piriformis muscle of Sprague Dawley rats.The two nerve ends shrank to form a 12-mm defect,and the nerve defect was repaired using a chitosan tube bridging autologous nerve segment （bridge group）,a chitosan tube-encapsulated autologous nerve segment （encapsulation group）,and a chitosan tube alone （chitosan tube alone group）,respectively.MAIN OUTCOME MEASURES：Histological and ultrastructural changes of the injured sciatic nerve;number of regenerated myelinated nerve fibers; nerve conduction velocity; leg muscle atrophy; and sciatic nerve functional index.RESULTS：At 4 months after implantation,the chitosan tube was absorbed.The tube was thin,but maintained the original shape,and vascular proliferation was observed around the tube.In the bridge group,regenerative myelinated nerve fibers were thick and orderly,with a thick myelin sheath and intact axonal structure.The number of myelinated nerve fibers and nerve conduction velocity were significantly greater compared with the other groups （P〈 0.01）.Moreover,nerve and muscle function was significantly improved following chitosan tube bridging autologous nerve segment treatment compared with the other groups （P〈 0.05 or P 〈 0.01）.CONCLUSION：Chitosan tube bridging autologous nerve segments exhibited better repair effects on nerve defects compared with chitosan tubeencapsulated autologous nerve segments and a chitosan tube alone.This method provided a simple and effective treatment for long-segmental nerve defects.展开更多
基金support of the National Natural Science Foundation of China(Grant No.52371279)the Program for International Exchange and Cooperation in Education by the Ministry of Education of the People's Republic of China(Grant No.57220500123).
文摘Lost circulation of drilling fluid is one of the most common and costly problems in drilling operations.This highlights the importance of wellbore strengthening treatment sthat can utilize lost circulation materials(LCMs)to seal fractures associated with the wellbore.In this work,a numerical model accounting for the deformation of surrounding rock,fluid flow in the fracture,fracture propagation,and the transport of LCMs is presented to investigate the wellbore strengthening,from the fracture initiation to the fracture arrest,due to plugs formed by LCMs.The equations governing the rock deformation and fluid flow are solved by the dual boundary element method and the finite volume method,respectively.The transport of LCMs is solved based on an empirical constitutive model in suspension flow,and several characteristic quantities are derived by dimensional analysis.It is found that two dimensionless parameters,dimensionless toughness and normalized initial particle concentration,control the migration of LCM particles.The numerical results show that the dimensionless toughness influences the entrance and bridging of LCMs while the initial concentration controls the location of the particle bridging.When the initial concentration is larger than 0.8,the particle bridging tends to occur near the fracture entry.Conversely,when the initial concentration is less than 0.8,the particle bridging occurs near the fracture tip.This work provides an effective tool to predict the LCM transport and plugging in the wellbore strengthening process.
文摘As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok’s Wat Po temple lies a quieter,gentler form of diplomacy—one that happens through kneading hands,respectful bows,and an ancient art passed down across generations.At the Wat Po Thai Traditional Medical School,headmaster Serat Tangtrongchitr sees Thai massage not only as a healing craft,but as a cultural bridge—one that connects people across borders,languages,and belief systems.“We don’t just teach massage,”Serat said,his voice calm but assured.“We teach a way of life.And when people from other cultures learn this with us—Chinese students included—they come to understand not just the techniques,but the heart of Thai culture.”
基金Supported by the Research Project of the Chinese Digestive Early Cancer Physicians’Joint Growth Program,No.GTCZ-2021-AH-34-0012.
文摘BACKGROUND Patients diagnosed with esophageal mucosal bridges often experience symptoms such as chest pain and dysphagia,which pose considerable challenges for endo-scopic surgical interventions.CASE SUMMARY We present a case involving early-stage esophageal cancer discovered in a resting room,notable for the rare manifestation of esophageal mucosal bridging.Following a comprehensive multidisciplinary discussion and the development of a treatment strategy,we proceeded with endoscopic submucosal dissection for the patient.During the procedure,we encountered operational challenges due to the presence of a diverticulum and a partial absence of the muscularis propria.To facilitate the retraction of a portion of the resected specimen,we utilized dental floss.Ultimately,we successfully excised the entire lesion.After a three-day period of fasting with a water-only diet,subsequent iodine water cholan-giography did not indicate any perforations,and the patient was advised to transition to a liquid diet.The patient was discharged five days post-operation.A follow-up endoscopy conducted three months later revealed scar-like changes in the mid-esophagus,with the patient reporting no significant discomfort.CONCLUSION In summary,although esophageal mucosal bridges are rarely documented,they should be considered in the differential diagnosis of mechanical dysphagia.Furthermore,endoscopic therapy represents a feasible approach for their mana-gement.
文摘The Emerging Markets and Developing Countries Forum on Bridging the AI Divide and Opening Ceremony of AIM Global CoE were held on July 27 in Minhang district,Shanghai.The event was hosted by AIM Global CoE,and co-organized by Shanghai Artificial Intelligence Research Institute(SAIRI),Shanghai Technology Innovation Center,Shanghai Grand Neobay Investment Development Group,and Organizing Committee of AI Journey Conference.Asian Association of Business Incubation(AABI)and SAIRI served as the international partners.
文摘Traditional Chinese medicine (TCM) with its millenniaold wisdom rooted in the principles of holistic Yin-Yang balance and “Bianzheng Lunzhi”[辨证论治, Zhenghou(证候) differentiation and treatment], has long offered a unique lens to understand human health and disease.However, the modern scientific interpretation of TCM remains at the stage of “knowing that it works, but not knowing why it works”.
基金supported by the National Natural Science Foundation of China(No.82170206 and No.82470213)Project of Disciplines of Excellence(No.20234Z0002)。
文摘Blinatumomab has demonstrated efficacy in B-cell acute lymphoblastic leukemia(B-ALL),achieving a measurable residual disease(MRD)negativity rate of 78%(1).Its addition to consolidation chemotherapy or administration prior to allogeneic hematopoietic stem cell transplantation(allo-HSCT)has been shown to significantly improve overall survival(OS)and relapse-free survival(RFS)in adult B-ALL patients(2,3).
文摘Biocatalysis with nicotinamide adenine dinucleotide phosphate(NADP)-dependent oxidoreductases faces a challenge in improving the efficiency of the costly cofactor utilization.Although enzyme fusion can offer cofactor regeneration,the high-volume input and limited cofactor recyclability still make the enzymatic processes unsustainable.Therefore,it is of great significance to reduce cofactor input in a fusion enzyme(FuE)system,but no successful practice has been reported.Herein,we design a decapeptide bridge,RRRQRRRARR(R10),with high affinity for NADPH to construct fusion oxidoreductases(phenylacetone monooxygenase and phosphite dehydrogenase)for ester synthesis and NADP recycling.The peptide bridge enables electrostatic cofactor channeling that transports NADPH/NADP^(+)across the peptide between the enzymes’NADP-binding pockets,so the fusion enzyme(FuE-R10)presents 2.1-folds and 2.0-folds higher conversions than mixed free enzymes and a flexible linker(GGGGSGGGGS)-fused enzyme,respectively,at NADPH/FuE of 0.1.The fusion enzyme,FuE-R5,bridged by a half-shortened linker,is proved more effective in facilitating cofactor channeling;compared to the mixed free enzymes,FuE-R5 exhibits two orders of magnitude reduction of NADPH input in ester synthesis.The work has thus demonstrated the potential of the cofactor bridging strategy in the development of sustainable cofactor-dependent cascade biocatalysis.
基金the Natural Science Foundation of China(11922415,12274471)Guangdong Basic and Applied Basic Research Foundation(2022A1515011168,2019A1515011718,2019A1515011337)the Key Research and Development Program of Guangdong Province,China(2019B110209003).
文摘We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.
基金This work was financially supported by the National Natural Science Foundation of China(No.22341303)forms part of the research program of DPI,project#841.
文摘In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ignored.Herein,we studied industrially important ternary composites,polypropylene(PP)/ethylene-octene copolymer(a polyolefin elastomer,POE)/talc systems,and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc particles.It is found that talc fillers concentrate in the PP phase using the“blend first”protocol,while more talc particles are located at the interface of PP and POE phases using the“filler first”protocol.Changing the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the“filler first”protocol.The linear rheology behavior indicates that besides the“volume exclusion effect”,the talc-POE hybrid network can further contribute to the reinforcement effect.Meanwhile,the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear,in contrast to the un-recoverable structures in the PP/talc binary composites.The correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers.
基金supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06).
文摘The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.
基金Supported by Financiamento e IncentivoàPesquisa(FIPE/HCPA)of Hospital de Clínicas de Porto Alegre,No.2020-0473.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is an aggressive malignant neoplasm that requires liver transplantation(LT).Despite patients with HCC being prioritized by most organ allocation systems worldwide,they still have to wait for long periods.Locoregional therapies(LRTs)are employed as bridging therapies in patients with HCC awaiting LT.Although largely used in the past,transarterial embolization(TAE)has been replaced by transarterial chemoembolization(TACE).However,the superiority of TACE over TAE has not been consistently shown in the literature.AIM To compare the outcomes of TACE and TAE in patients with HCC awaiting LT.METHODS All consecutive patients with HCC awaiting LT between 2011 and 2020 at a single center were included.All patients underwent LRT with either TACE or TAE.Some patients also underwent percutaneous ethanol injection(PEI),concom-itantly or in different treatment sessions.The choice of LRT for each HCC nodule was determined by a multidisciplinary consensus.The primary outcome was waitlist dropout due to tumor progression,and the secondary outcome was the occurrence of adverse events.In the subset of patients who underwent LT,complete pathological response and post-transplant recurrence-free survival were also assessed.RESULTS Twelve(18.5%)patients in the TACE group(only TACE and TACE+PEI;n=65)and 3(7.9%)patients in the TAE group(only TAE and TAE+PEI;n=38)dropped out of the waitlist due to tumor progression(P log-rank test=0.29).Adverse events occurred in 8(12.3%)and 2(5.3%)patients in the TACE and TAE groups,respectively(P=0.316).Forty-eight(73.8%)of the 65 patients in the TACE group and 29(76.3%)of the 38 patients in the TAE group underwent LT(P=0.818).Among these patients,complete pathological response was detected in 7(14.6%)and 9(31%)patients in the TACE and TAE groups,respectively(P=0.145).Post-LT,HCC recurred in 9(18.8%)and 4(13.8%)patients in the TACE and TAE groups,respectively(P=0.756).Posttransplant recurrence-free survival was similar between the groups(P log-rank test=0.71).CONCLUSION Dropout rates and posttransplant recurrence-free survival of TAE were similar to those of TACE in patients with HCC.Our study reinforces the hypothesis that TACE is not superior to TAE as a bridging therapy to LT in patients with HCC.
文摘Objective:To analyze the clinical effect of a simple egg membrane patch bridging method in repairing tympanic membrane perforation.Methods:A total of 93 tympanic membrane perforation patients admitted to the hospital between September 2022 and October 2023 were selected and divided into two groups according to the random number table method.The control group implemented the conventional treatment(n=46 cases),and the patch group adopted the simple egg membrane patch bridging method(n=47 cases).The healing rate of the tympanic membrane,the air-bone gap,the air conduction hearing threshold,the dry ear rate,and the incidence of complications in both groups were compared before and after treatment.Results:The healing rate of the tympanic membrane in the patch group was significantly higher than that of the control group(95.75%vs.76.09%),with P<0.05;there was no difference in the air-bone gap and air conduction hearing threshold levels between the two groups before treatment(P>0.05),and the hearing indexes of the patch group were significantly lower than those of the control group 3 months after treatment(P<0.05);the dry ear rate in the patch group was significantly higher than that of the control group after treatment(85.11%vs.67.39%),and the total incidence of complications was also significantly lower than that of the control group(6.38%vs.21.74%),with P<0.05.Conclusion:The simple egg membrane patch bridging method is effective in repairing tympanic membrane perforation,which can effectively improve patients’hearing levels and reduce the occurrence of post-treatment complications.Thus,it is worth popularizing and applying in the clinic.
文摘AIM:To analyze whether high-intensity focused ultrasound(HIFU) ablation is an effective bridging therapy for patients with hepatocellular carcinoma(HCC).METHODS:From January 2007 to December 2010,49 consecutive HCC patients were listed for liver transplantation(UCSF criteria).The median waiting time for transplantation was 9.5 mo.Twenty-nine patients received transarterial chemoembolization(TACE) as a bringing therapy and 16 patients received no treatment before transplantation.Five patients received HIFU ablation as a bridging therapy.Another five patients with the same tumor staging(within the UCSF criteria) who received HIFU ablation but not on the transplant list were included for comparison.Patients were comparable in terms of Child-Pugh and model for end-stage liver disease scores,tumor size and number,and cause of cirrhosis.RESULTS:The HIFU group and TACE group showed no difference in terms of tumor size and tumor number.One patient in the HIFU group and no patient in the TACE group had gross ascites.The median hospital stay was 1 d(range,1-21 d) in the TACE group and two days(range,1-9 d) in the HIFU group(P < 0.000).No HIFU-related complication occurred.In the HIFU group,nine patients(90%) had complete response and one patient(10%) had partial response to the treatment.In the TACE group,only one patient(3%) had response to the treatment while 14 patients(48%) had stable disease and 14 patients(48%) had progressive disease(P = 0.00).Seven patients in the TACE group and no patient in the HIFU group dropped out from the transplant waiting list(P = 0.559).CONCLUSION:HIFU ablation is safe and effective in the treatment of HCC for patients with advanced cirrhosis.It may reduce the drop-out rate of liver transplant candidate.
文摘Several therapeutic procedures have been proposed as bridging treatments for patients with hepatocellular carcinoma(HCC)awaiting liver transplantation(LT).The most used treatments include transarterial chemoembolization and radiofrequency ablation.Surgical resection has also been successfully used as a bridging procedure,and LT should be considered a rescue treatment in patients with previous HCC resection who experience tumor recurrence or post-treatment severe decompensation of liver function.The aims of bridging treatments include decreasing the waiting list dropout rate before transplantation,reducing HCC recurrence after transplantation,and improving post-transplant overall survival.To date,no data from prospective randomized studies are available;however,for HCC patients listed for LT within the Milan criteria,prolonging the waiting time over 6-12 mo is a risk factor for tumor spread.Bridging treatments are useful in containing tumor progression and decreasing dropout.Furthermore,the response to pre-LT treatments may represent a surrogate marker of tumor biological aggressiveness and could therefore be evaluated to prioritize HCC candidates for LT.Lastly,although a definitive conclusion can not be reached,the experiences reported to date suggest a positive impact of these treatments on both tumor recurrence and post-transplant patient survival.Advanced HCC may be downstaged to achieve and maintain the current conventional criteria for inclusion in the waiting list for LT.Recent studies have demonstrated that successfully downstaged patients can achieve a 5-year survival rate comparable to that of patients meeting the conventional criteria without requiring downstaging.
文摘BACKGROUND Prospective study of 200 patients with hepatocellular carcinoma(HCC)that underwent liver transplant(LT)after drug-eluting beads transarterial chemoembolization(DEB-TACE)for downstaging versus bridging.Overall survival and tumor recurrence rates were calculated,eligibility for LT,time on the waiting list and radiological response were compared.After TACE,only patients within Milan Criteria(MC)were transplanted.More patients underwent LT in bridging group.Five-year post-transplant overall survival,recurrence-free survival has no difference between the groups.Complete response was observed more frequently in bridging group.Patients in DS group can achieve posttransplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.AIM To determine long-term outcomes of patients with HCC that underwent LT after DEB-TACE for downstaging vs bridging.METHODS Prospective cohort study of 200 patients included from April 2011 through June 2014.Bridging group included patients within MC.Downstaging group(out of MC)was divided in 5 subgroups(G1 to G5).Total tumor diameter was≤8 cm for G1,2,3,4(n=42)and was>8 cm for G5(n=22).Downstaging(n=64)and bridging(n=136)populations were not significantly different.Overall survival and tumor recurrence rates were calculated by the Kaplan-Meier method.Additionally,eligibility for LT,time on the waiting list until LT and radiological response were compared.RESULTS After TACE,only patients within MC were transplanted.More patients underwent LT in bridging group 65.9%(P=0.001).Downstaging population presented:higher number of nodules 2.81(P=0.001);larger total tumor diameter 8.09(P=0.001);multifocal HCC 78%(P=0.001);more post-transplantation recurrence 25%(P=0.02).Patients with maximal tumor diameter up to 7.05 cm were more likely to receive LT(P=0.005).Median time on the waiting list was significantly longer in downstaging group 10.6 mo(P=0.028).Five-year posttransplant overall survival was 73.5%in downstaging and 72.3%bridging groups(P=0.31),and recurrence-free survival was 62.1%in downstaging and 74.8%bridging groups(P=0.93).Radiological response:complete response was observed more frequently in bridging group(P=0.004).CONCLUSION Tumors initially exceeding the MC down-staged after DEB-TACE,can achieve post-transplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.
文摘High-intensity focused ultrasound(HIFU)is a noninvasive modality that uses an extracorporeal source of focused ultrasound energy.This technique was introduced by Lynn et al and is able to induce coagulative necrosis in selected tissues without damaging adjacent structures.Although HIFU has been studied for 50years,recent technological developments now allow its use for tumours of the liver,prostate and other sites.In liver disease,HIFU has been used to treat unresectable,advanced stages of hepatocellular carcinoma(HCC)and liver metastases.Hepatocellular carcinoma is a serious health problem worldwide and is endemic in some areas because of its association with hepatitis B and C viruses(in 20%of cases).Liver transplantation(LT)has become one of the best treatments available because it removes both the tumour and the underlying liver disease such as cirrhosis(which is present in approximately 80%of cases).The prerequisite for longterm transplant success depends on tumour load and strict selection criteria regarding the size and number of tumour nodules.The need to obtain the optimal benefit from the limited number of organs available has prompted strict selection criteria limited to only those patients with early HCC who have a better long-term outcome after LT.The so-called"bridging therapy"has the aim of controlling disease burden for patients who are on the organ transplant waiting list.Amongst various treatment options,transarterial chemoembolisation and radiofrequency ablation are the most popular treatment choices.Recently,Cheung et al demonstrated that HIFU ablation is a safe and effective method for the treatment of HCC patients with advanced cirrhosis as a bridging therapy and that it reduced the dropout rate from the liver transplant waiting list.In this commentary,we discuss the current value of HIFU in the treatment of liver disease,including its value as a bridging therapy,and examine the potential advantages of other therapeutic strategies.
文摘Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation untreated.Degradable materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix stimulation.Despite the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not optimized.The current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular product.It is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and diverters.Mathematical modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage optimization.In this work,we develop a numerical model to study fiber dynamics in fluid flow.We employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected spheres.The discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous interactions.The focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in carbonates.The trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental observations.The present numerical investigation reveals that the bridging capability of the fiber–fluid system can be enhanced by increasing the fiber loading,selecting fibers with higher stiffness,reducing the injection flow rate,reducing the suspending fluid viscosity or increasing the attractive cohesive forces among fibers by using sticky fibers.
基金the Veterans Administrationthe Canadian Spinal Research Organizationthe California Institute for Regenerative Medicine
文摘Spinal cord injury （SCI） damages not only the gray matter neurons, but also the white matter axonal tracts that carry signals to and from the brain, re- suiting in permanent loss of function below injury. Neural stem cells （NSCs） have high therapeutic potential for reconstruction of the injured spinal cord since they can potentially fnrm neuronal relays to bridge functional con-nectivity between separated spinal cord segments. This requires host axonal regeneration into and connectivity with donor neurons, and axonal growth and connectivity of donor neurons to host central nervous system （CNS） circuitry. In this mini-review, we will discuss key studies that explore novel neuronal relay formation by grafting NSCs in models of SCI, with emphasis on long-distance axonal growth and connectivity of NSCs grafted into in-jured spinal cord.
文摘We present a case of a 71-year-old male who hadchest symptoms at rest and during effort. He had felt chest oppression during effort for 1 year,and his chest symptoms had recently worsened. One month before admission he felt chest squeezing at rest in the early morning. He presented at our institution to evaluate his chest symptoms. Electrocardiography and echocardiography failed to show any specific changes. Because of the possibility that his chest symptoms were due to myocardial ischemia,he was admitted to our institution for coronary angiography(CAG). An initial CAG showed mild atherosclerotic changes in the proximal segment of the left anterior descending coronary artery(LAD) and mid-segment of the left circumflex coronary artery. Subsequent spasm provocation testing using acetylcholine revealed a bilateral coronary vasospasm,which was relieved after the intracoronary infusion of nitroglycerin. Finally,a CAG showed myocardial bridging(MB) of the mid-distal segments of the LAD. Fractional flow reserve using the intravenous administration of adenosine triphosphate was positive at 0.77,which jumped up to 0.90 through the myocardial bridging segments when the pressure wire was pulled back. Thus,coronary vasospasm and MB might have contributed to his chest symptoms at rest and during effort. Interventional cardiologists should consider the presence of MB as a potential cause of myocardial ischemia.
文摘BACKGROUND：Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain unclear.OBJECTIVE：To explore the feasibility and advantages of chitosan tube bridging autologous nerve segments for repairing 12-mm sciatic nerve defects in rats.DESIGN,TIME AND SETTING：A randomized,controlled,animal study using nerve tissue engineering was performed at the Animal Laboratory and Laboratory of Histology and Embryology,Liaoning Medical University from June 2008 to March 2009.MATERIALS：Chitosan powder was purchased from Jinan Haidebei Marine Bioengineering,China.METHODS：A sciatic nerve segment of approximately 8 mm was excised from the posterior margin of the piriformis muscle of Sprague Dawley rats.The two nerve ends shrank to form a 12-mm defect,and the nerve defect was repaired using a chitosan tube bridging autologous nerve segment （bridge group）,a chitosan tube-encapsulated autologous nerve segment （encapsulation group）,and a chitosan tube alone （chitosan tube alone group）,respectively.MAIN OUTCOME MEASURES：Histological and ultrastructural changes of the injured sciatic nerve;number of regenerated myelinated nerve fibers; nerve conduction velocity; leg muscle atrophy; and sciatic nerve functional index.RESULTS：At 4 months after implantation,the chitosan tube was absorbed.The tube was thin,but maintained the original shape,and vascular proliferation was observed around the tube.In the bridge group,regenerative myelinated nerve fibers were thick and orderly,with a thick myelin sheath and intact axonal structure.The number of myelinated nerve fibers and nerve conduction velocity were significantly greater compared with the other groups （P〈 0.01）.Moreover,nerve and muscle function was significantly improved following chitosan tube bridging autologous nerve segment treatment compared with the other groups （P〈 0.05 or P 〈 0.01）.CONCLUSION：Chitosan tube bridging autologous nerve segments exhibited better repair effects on nerve defects compared with chitosan tubeencapsulated autologous nerve segments and a chitosan tube alone.This method provided a simple and effective treatment for long-segmental nerve defects.
