Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture ...Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture complexity.We performed a series of laboratory experiments to explore the key mechanisms governing the breakdown pressures of shale during cryogenic fracturing.In this study,cylindrical shale samples were pre-conditioned by exposing a borehole to low-temperature LN_(2) for a certain time period,and then,the samples were fractured using gaseous N_(2) under triaxial stress and a high reservoir temperature.The effects of various key parameters on the breakdown pressure were investigated,including the duration of the low-temperature LN_(2) treatment,the confining pressure,the reservoir temperature,and the direction of the shale bedding relative to the borehole axis.The results demonstrate that the injection of low-temperature LN_(2) as a pre-fracturing fluid into a borehole can significantly reduce the breakdown pressure of the shale during subsequent nitrogen fracturing.This reduction in breakdown pressure can be further intensified by increasing the duration of the LN_(2) pre-conditioning.Without LN_(2) pre-conditioning,the breakdown pressure initially increases and then decreases with increasing reservoir temperature.When LN_(2) pre-conditioning is applied,the breakdown pressure keeps decreasing with increasing reservoir temperature.As the confining pressure increased,the breakdown pressure increased linearly in the tests with and without LN_(2) pre-conditioning.The experimental results demonstrate that LN_(2) preconditioning before N_(2) fracturing is a promising waterless fracturing technique that reduces the breakdown pressure and enhances the fracture complexity.展开更多
The effect of externally applied mechanical pre-conditioning, i.e. pre-impact treatment, on the fracture resistance was investigated for polypropylene （PP）. Impact strength was obtained via notched and/or unnotched ...The effect of externally applied mechanical pre-conditioning, i.e. pre-impact treatment, on the fracture resistance was investigated for polypropylene （PP）. Impact strength was obtained via notched and/or unnotched samples. It has been shown that the pre-impact treatment is favorable to the improvement of the fracture resistance. The impact strength increases linearly with the applied pre-impact energy. Both optical and SEM results show that there are at least two possible mechanisms for the improvement of the fracture resistance. One is the crack blunting effect which is introduced to notched sample by pre-impact treatment, reducing the sensitivity of PP to the applied notch. The other is the formation of large amount of microvoids induced by pre-impact treatment, which changes the stress distribution and induces intensive plastic deformation of PP at the second impact measurement, leading to the improvement of the fracture resistance.展开更多
In multiuser massive Multiple Input Multiple Output(MIMO)systems,a large amount of antennas are deployed at the Base Station(BS).In this case,the Minimum Mean Square Error(MMSE)detector with soft-output can achieve th...In multiuser massive Multiple Input Multiple Output(MIMO)systems,a large amount of antennas are deployed at the Base Station(BS).In this case,the Minimum Mean Square Error(MMSE)detector with soft-output can achieve the near-optimal performance at the cost of a large-scale matrix inversion operation.The optimization algorithms such as Gradient Descent(GD)method have received a lot of attention to realize the MMSE detection efficiently without a large scale matrix inversion operation.However,they converge slowly when the condition number of the MMSE filtering matrix(the coefficient matrix)increases,which can compromise the efficiency of their implementation.Moreover,their soft information computation also involves a large-scale matrix-matrix multiplication operation.In this paper,a low-complexity soft-output signal detector based on Adaptive Pre-conditioned Gradient Descent(APGD-SOD)method is proposed to realize the MMSE detection with soft-output for uplink multiuser massive MIMO systems.In the proposed detector,an Adaptive Pre-conditioner(AP)matrix obtained through the Quasi-Newton Symmetric Rank One(QN-SR1)update in each iteration is used to accelerate the convergence of the GD method.The QN-SR1 update supports the intuitive notion that for the quadractic problem one should strive to make the pre-conditioner matrix close to the inverse of the coefficient matrix,since then the condition number would be close to unity and the convergence would be rapid.By expanding the signal model of the massive MIMO system and exploiting the channel hardening property of massive MIMO systems,the computational complexity of the soft information is simplified.The proposed AP matrix is applied to the GD method as a showcase.However,it also can be used by Conjugate Gradient(CG)method due to its generality.It is demonstrated that the proposed detector is robust and its convergence rate is superlinear.Simulation results show that the proposed detector converges at most four iterations.Simulation results also show that the proposed approach achieves a better trade-off between the complexity and the performance than several existing detectors and achieves a near-optimal performance of the MMSE detector with soft-output at four iterations without a complicated large scale matrix inversion operation,which entails a big challenge for the efficient implementation.展开更多
Recent results emphasize the supportive effects of adipose-derived multipotent stem/progenitor cells(ADSPCs)in peripheral nerve recovery.Cultivation under hypoxia is considered to enhance the release of the regenerati...Recent results emphasize the supportive effects of adipose-derived multipotent stem/progenitor cells(ADSPCs)in peripheral nerve recovery.Cultivation under hypoxia is considered to enhance the release of the regenerative potential of ADSPCs.This study aimed to examine whether peripheral nerve regeneration in a rat model of autologous sciatic nerve graft benefits from an additional custom-made fibrin conduit seeded with hypoxic pre-conditioned(2%oxygen for 72 hours)autologous ADSPCs(n=9).This treatment mode was compared with three others:fibrin conduit seeded with ADSPCs cultivated under normoxic conditions(n=9);non-cell-carrying conduit(n=9);and nerve autograft only(n=9).A 16-week follow-up included functional testing(sciatic functional index and static sciatic index)as well as postmortem muscle mass analyses and morphometric nerve evaluations(histology,g-ratio,axon density,and diameter).At 8 weeks,the hypoxic pre-conditioned group achieved significantly higher sciatic functional index/static sciatic index scores than the other three groups,indicating faster functional regeneration.Furthermore,histologic evaluation showed significantly increased axon outgrowth/branching,axon density,remyelination,and a reduced relative connective tissue area.Hypoxic pre-conditioned ADSPCs seeded in fibrin conduits are a promising adjunct to current nerve autografts.Further studies are needed to understand the underlying cellular mechanism and to investigate a potential application in clinical practice.展开更多
Investigations were conducted to establish effects of fermentation and drying on the fermentation index （FI） and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design...Investigations were conducted to establish effects of fermentation and drying on the fermentation index （FI） and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage （0, 3, 7 and 10 d） and fermentation time （0, 3 and 6 d） to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage （0, 3, 7 and 10 d） and drying time （0, 3 and 7 d） being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans （six days fermentation） also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying （seven days）. FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying （seven days）. Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.展开更多
Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitatio...Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after stroke.In this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral ischemia.We also examined the role of exercise-induced circulating factors in these effects.Adult mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery occlusion.We found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory function.Further analysis showed that circulating adiponectin plays a critical role in these preventive effects of exercise.Agonist activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise effects.In summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.展开更多
Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definit...Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definition of PRS has evolved over the years,from changes in arterial blood pressures and heart and/or de-creases in the systemic vascular resistance and cardiac output to including the fibrinolysis and grading the severity of PRS.However,all that did not reflect on the management of PRS or its impact on the outcomes.In recent years,new scientific techniques and new technology have been in the pipeline to better understand,manage and maybe prevent PRS.These new methods and techniques are still in the infancy,and they have to be proven not in prevention and management of PRS but their effects in the patient and graft outcomes.In this article,we will review the long history of PRS,its definition,etiology,mana-gement and most importantly the new advances in science and technology to prevent and properly manage PRS.展开更多
Hepatic ischemia-reperfusion injury (IRI) limits access to transplantation. Heme oxygenase-1 (HO-1) is a powerful antioxidant enzyme which degrades free heme into biliverdin,free iron and carbon monoxide. HO-1 and its...Hepatic ischemia-reperfusion injury (IRI) limits access to transplantation. Heme oxygenase-1 (HO-1) is a powerful antioxidant enzyme which degrades free heme into biliverdin,free iron and carbon monoxide. HO-1 and its metabolites have the ability to modulate a wide variety of inflammatory disorders including hepatic IRI. Mechanisms of this protective effect include reduction of oxygen free radicals,alteration of macrophage and T cell phenotype. Further work is required to understand the physiological importance of the many actions of HO-1 identified experimentally,and to harness the protective effect of HO-1 for therapeutic potential.展开更多
Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As anima...Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As animal models are better characterized and developed, and more insights are gained into the pathophysiology of hepatic ischemia reperfusion injury in humans the questions into exactly how oxidants participate in this injury are becoming more refined. These questions include effects of cellular location, timing of injury, and ability of therapeutics to access this site are increasing our appreciation of the complexity of ischemia reperfusion and improving attempts to ameliorate its effects. In this review, we aim to discuss the various methods to alter redox chemistry during ischemia reperfusion injury and future prospects for preventing organ injury during hepatic ischemia reperfusion.展开更多
Highly precise acoustic impedance inversion is a key technology for pre-drilling prediction by VSP data. In this paper, based on the facts that VSP data has high resolution, high signal to noise ratio, and the downgoi...Highly precise acoustic impedance inversion is a key technology for pre-drilling prediction by VSP data. In this paper, based on the facts that VSP data has high resolution, high signal to noise ratio, and the downgoing and upgoing waves can be accurately separated, we propose a method of predicting the impedance below the borehole in front of the bit using VSP data. First, the method of nonlinear iterative inversion is adopted to invert for impedance using the VSP corridor stack. Then, by modifying the damping factor in the iteration and using the preconditioned conjugate gradient method to solve the equations, the stability and convergence of the inversion results can be enhanced. The results of theoretical models and actual data demonstrate that the method is effective for pre-drilling prediction using VSP data.展开更多
Chronic wound healing has long been an unmet medical need in the field of wound repair,with diabetes being one of the major etiologies.Diabetic chronic wounds(DCWs),especially diabetic foot ulcers,are one of the most ...Chronic wound healing has long been an unmet medical need in the field of wound repair,with diabetes being one of the major etiologies.Diabetic chronic wounds(DCWs),especially diabetic foot ulcers,are one of the most threatening chronic complications of diabetes.Although the treatment strategies,drugs,and dressings for DCWs have made great progress,they remain ineffective in some patients with refractory wounds.Stem cell-based therapies have achieved specific efficacy in various fields,with mesenchymal stem cells(MSCs)being the most widely used.Although MSCs have achieved good feedback in preclinical studies and clinical trials in the treatment of cutaneous wounds or other situations,the potential safety concerns associated with allogeneic/autologous stem cells and unknown long-term health effects need further attention and supervision.Recent studies have reported that stem cells mainly exert their trauma repair effects through paracrine secretion,and exosomes play an important role in intercellular communication as their main bioactive component.MSC-derived exosomes(MSC-Exos)inherit the powerful inflammation and immune modulation,angiogenesis,cell proliferation and migration promotion,oxidative stress alleviation,collagen remodeling imbalances regulation of their parental cells,and can avoid the potential risks of direct stem cell transplantation to a large extent,thus demonstrating promising performance as novel"cell-free"therapies in chronic wounds.This review aimed to elucidate the potential mechanism and update the progress of MSC-Exos in DCW healing,thereby providing new therapeutic directions for DCWs that are difficult to be cured using conventional therapy.展开更多
The precursors of dipole blocking are obtained by a numerical approach based upon a quasi-geostrophic barotropic planetary- to synoptic-scale interaction model without topography and with a localized synoptic-scale wa...The precursors of dipole blocking are obtained by a numerical approach based upon a quasi-geostrophic barotropic planetary- to synoptic-scale interaction model without topography and with a localized synoptic-scale wave-maker. The optimization problem related to the precursors of blocking is formulated and the nonlinear optimization method is used to examine the optimal synoptic-scale initial field successfully. The results show that the prominent characteristics of the optimal synoptic-scale initial field are that the synoptic-scale wave train structures exist upstream of the incipient blocking. In addition, the large-scale low/high eddy-forcing pattern upstream of the incipient blocking is an essential precondition for the onset of dipole blocking.展开更多
In the process of tobacco production, the moisture content of tobacco leaves directly affects the quality of tobacco leaf. Since the water content in the leaf is low, it needs to process with the conditioning treatmen...In the process of tobacco production, the moisture content of tobacco leaves directly affects the quality of tobacco leaf. Since the water content in the leaf is low, it needs to process with the conditioning treatment for a short time beforetobacco grading, so as to improve the tobacco moisture content and reduce breakage, as well as ensure the quality and yield of tobacco, ahd meet the requirements of the follow-up process of tobacco. Therefore, a comprehensive overview was given to the pre-conditioning method for tobacco leaf, and the current application status of tobacco leaf pre-conditioning equipment in China was explored.展开更多
Changes in total polyphenols, O-diphenols and anthocyanin concentrations during fermentation and drying of pulp pre-conditioned cocoa （Theobroma cacao） beans were investigated using standard analytical methods. Incr...Changes in total polyphenols, O-diphenols and anthocyanin concentrations during fermentation and drying of pulp pre-conditioned cocoa （Theobroma cacao） beans were investigated using standard analytical methods. Increasing pod storage, fermentation and drying led to variable reductions in total polyphenols, O-diphenols and anthocyanins content of the beans. The rates of reduction were however more pronounced during fermentation than pod storage and drying. Storage of cocoa pods between 3-7 days with 6 and 7 days of fermentation and drying respectively retained 85%-90% of the total polyphenol and O-diphenols of the cocoa beans. Similarly, anthocyanin content of beans from the 10 days of pod storage decreased by 70% in the sixth day of fermentation. Pod storage decreased the anthocyanin content at all periods of fermentation. These suggest that the post-harvest treatments of pod storage, fermentation and drying all results in variable reductions in polyphenolic content （total polyphenols and O-diphenols） and anthocyanins content of cocoa beans.展开更多
Ischemic heart disease (IHD) accelerates death of cardiomyocytes and leads to the onset of cardiac failure. Due to the application of stem cells, there exists a potential for the regeneration of a damaged myocardium. ...Ischemic heart disease (IHD) accelerates death of cardiomyocytes and leads to the onset of cardiac failure. Due to the application of stem cells, there exists a potential for the regeneration of a damaged myocardium. Here we present a brief review of the modern data on the application of various types of stem cells for the IHD therapy. We consider different types of stem cells, which are most preferable for the clinical application, including mesenchymal stem cells, cardiac stem cells, embryonic stem cells, iPS cells and others. In particular, we discuss their advantages and strategies which can be applied in order to boost their regenerative potential, as well as optimization of their delivery. Besides, our review refers to the contemporary achievements in the field of tissue engineering of heart, using both polymer scaffolds and scaffold-free constructs. We also discuss the most prominent known clinical trials on stem cell therapy of ischemic heart disease.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.51674247)the project for Fundamental Research Funds for the Central Universities(China University of Mining and Technology)under No.2015XKZD06.
文摘Cryogenic fracturing with liquid nitrogen(LN_(2))offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing,as well as potentially enhancing the fracture complexity.We performed a series of laboratory experiments to explore the key mechanisms governing the breakdown pressures of shale during cryogenic fracturing.In this study,cylindrical shale samples were pre-conditioned by exposing a borehole to low-temperature LN_(2) for a certain time period,and then,the samples were fractured using gaseous N_(2) under triaxial stress and a high reservoir temperature.The effects of various key parameters on the breakdown pressure were investigated,including the duration of the low-temperature LN_(2) treatment,the confining pressure,the reservoir temperature,and the direction of the shale bedding relative to the borehole axis.The results demonstrate that the injection of low-temperature LN_(2) as a pre-fracturing fluid into a borehole can significantly reduce the breakdown pressure of the shale during subsequent nitrogen fracturing.This reduction in breakdown pressure can be further intensified by increasing the duration of the LN_(2) pre-conditioning.Without LN_(2) pre-conditioning,the breakdown pressure initially increases and then decreases with increasing reservoir temperature.When LN_(2) pre-conditioning is applied,the breakdown pressure keeps decreasing with increasing reservoir temperature.As the confining pressure increased,the breakdown pressure increased linearly in the tests with and without LN_(2) pre-conditioning.The experimental results demonstrate that LN_(2) preconditioning before N_(2) fracturing is a promising waterless fracturing technique that reduces the breakdown pressure and enhances the fracture complexity.
基金supported by the National Natural Science Foundation(No.50973090)Program for New Century Excellent Talents in Universities(NCET-08-0823)Sichuan Youthful Science and Technology Foundation (07ZQ026-003)
文摘The effect of externally applied mechanical pre-conditioning, i.e. pre-impact treatment, on the fracture resistance was investigated for polypropylene （PP）. Impact strength was obtained via notched and/or unnotched samples. It has been shown that the pre-impact treatment is favorable to the improvement of the fracture resistance. The impact strength increases linearly with the applied pre-impact energy. Both optical and SEM results show that there are at least two possible mechanisms for the improvement of the fracture resistance. One is the crack blunting effect which is introduced to notched sample by pre-impact treatment, reducing the sensitivity of PP to the applied notch. The other is the formation of large amount of microvoids induced by pre-impact treatment, which changes the stress distribution and induces intensive plastic deformation of PP at the second impact measurement, leading to the improvement of the fracture resistance.
基金supported by National Natural Science Foundation of China under Grant 61501072 and 61701062Chongqing Research Program of Basic Research and Frontier Technology under Grant cstc2019jcyj-msxmX0079Program for Changjiang Scholars and Innovative Research Team in University under Grant IRT16R72.
文摘In multiuser massive Multiple Input Multiple Output(MIMO)systems,a large amount of antennas are deployed at the Base Station(BS).In this case,the Minimum Mean Square Error(MMSE)detector with soft-output can achieve the near-optimal performance at the cost of a large-scale matrix inversion operation.The optimization algorithms such as Gradient Descent(GD)method have received a lot of attention to realize the MMSE detection efficiently without a large scale matrix inversion operation.However,they converge slowly when the condition number of the MMSE filtering matrix(the coefficient matrix)increases,which can compromise the efficiency of their implementation.Moreover,their soft information computation also involves a large-scale matrix-matrix multiplication operation.In this paper,a low-complexity soft-output signal detector based on Adaptive Pre-conditioned Gradient Descent(APGD-SOD)method is proposed to realize the MMSE detection with soft-output for uplink multiuser massive MIMO systems.In the proposed detector,an Adaptive Pre-conditioner(AP)matrix obtained through the Quasi-Newton Symmetric Rank One(QN-SR1)update in each iteration is used to accelerate the convergence of the GD method.The QN-SR1 update supports the intuitive notion that for the quadractic problem one should strive to make the pre-conditioner matrix close to the inverse of the coefficient matrix,since then the condition number would be close to unity and the convergence would be rapid.By expanding the signal model of the massive MIMO system and exploiting the channel hardening property of massive MIMO systems,the computational complexity of the soft information is simplified.The proposed AP matrix is applied to the GD method as a showcase.However,it also can be used by Conjugate Gradient(CG)method due to its generality.It is demonstrated that the proposed detector is robust and its convergence rate is superlinear.Simulation results show that the proposed detector converges at most four iterations.Simulation results also show that the proposed approach achieves a better trade-off between the complexity and the performance than several existing detectors and achieves a near-optimal performance of the MMSE detector with soft-output at four iterations without a complicated large scale matrix inversion operation,which entails a big challenge for the efficient implementation.
基金support by the Faculty of Medicine,Ludwig-Maximilians-University(FöFoLe,Project 843 and 955,to TH and MMS).
文摘Recent results emphasize the supportive effects of adipose-derived multipotent stem/progenitor cells(ADSPCs)in peripheral nerve recovery.Cultivation under hypoxia is considered to enhance the release of the regenerative potential of ADSPCs.This study aimed to examine whether peripheral nerve regeneration in a rat model of autologous sciatic nerve graft benefits from an additional custom-made fibrin conduit seeded with hypoxic pre-conditioned(2%oxygen for 72 hours)autologous ADSPCs(n=9).This treatment mode was compared with three others:fibrin conduit seeded with ADSPCs cultivated under normoxic conditions(n=9);non-cell-carrying conduit(n=9);and nerve autograft only(n=9).A 16-week follow-up included functional testing(sciatic functional index and static sciatic index)as well as postmortem muscle mass analyses and morphometric nerve evaluations(histology,g-ratio,axon density,and diameter).At 8 weeks,the hypoxic pre-conditioned group achieved significantly higher sciatic functional index/static sciatic index scores than the other three groups,indicating faster functional regeneration.Furthermore,histologic evaluation showed significantly increased axon outgrowth/branching,axon density,remyelination,and a reduced relative connective tissue area.Hypoxic pre-conditioned ADSPCs seeded in fibrin conduits are a promising adjunct to current nerve autografts.Further studies are needed to understand the underlying cellular mechanism and to investigate a potential application in clinical practice.
文摘Investigations were conducted to establish effects of fermentation and drying on the fermentation index （FI） and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage （0, 3, 7 and 10 d） and fermentation time （0, 3 and 6 d） to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage （0, 3, 7 and 10 d） and drying time （0, 3 and 7 d） being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans （six days fermentation） also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying （seven days）. FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying （seven days）. Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.
基金supported by STI2030-Major Projects,No.2022ZD0207600(to LZ)the National Natural Science Foundation of China,Nos.32070955(to LZ),U22A20301(to KFS)+3 种基金the Natural Science Foundation of Guangdong Province,No.2021A1515012197(to HO)Guangzhou Core Medical Disciplines Project,No.2021-2023(to HO)Key Research and Development Plan of Ningxia Hui Automomous Region,No.2022BEG01004(to KFS)Science and Technology Program of Guangzhou,China,No.202007030012(to KFS and LZ)。
文摘Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after stroke.In this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral ischemia.We also examined the role of exercise-induced circulating factors in these effects.Adult mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery occlusion.We found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory function.Further analysis showed that circulating adiponectin plays a critical role in these preventive effects of exercise.Agonist activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise effects.In summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.
文摘Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definition of PRS has evolved over the years,from changes in arterial blood pressures and heart and/or de-creases in the systemic vascular resistance and cardiac output to including the fibrinolysis and grading the severity of PRS.However,all that did not reflect on the management of PRS or its impact on the outcomes.In recent years,new scientific techniques and new technology have been in the pipeline to better understand,manage and maybe prevent PRS.These new methods and techniques are still in the infancy,and they have to be proven not in prevention and management of PRS but their effects in the patient and graft outcomes.In this article,we will review the long history of PRS,its definition,etiology,mana-gement and most importantly the new advances in science and technology to prevent and properly manage PRS.
基金Supported by The Maurice Wohl Fellowship from the Royal College of Surgeons of Edinburgh and a Research Training Fel-lowship from The Wellcome Trust (to Richards JA)Tenovus Scotland and The Peel Medical Research Trust to support his cur-rent work (to Richards JA)A Clinician Scientist Fellowship from the Academy of Medical Sciences and the Health Foundation (to Devey LR)
文摘Hepatic ischemia-reperfusion injury (IRI) limits access to transplantation. Heme oxygenase-1 (HO-1) is a powerful antioxidant enzyme which degrades free heme into biliverdin,free iron and carbon monoxide. HO-1 and its metabolites have the ability to modulate a wide variety of inflammatory disorders including hepatic IRI. Mechanisms of this protective effect include reduction of oxygen free radicals,alteration of macrophage and T cell phenotype. Further work is required to understand the physiological importance of the many actions of HO-1 identified experimentally,and to harness the protective effect of HO-1 for therapeutic potential.
文摘Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As animal models are better characterized and developed, and more insights are gained into the pathophysiology of hepatic ischemia reperfusion injury in humans the questions into exactly how oxidants participate in this injury are becoming more refined. These questions include effects of cellular location, timing of injury, and ability of therapeutics to access this site are increasing our appreciation of the complexity of ischemia reperfusion and improving attempts to ameliorate its effects. In this review, we aim to discuss the various methods to alter redox chemistry during ischemia reperfusion injury and future prospects for preventing organ injury during hepatic ischemia reperfusion.
文摘Highly precise acoustic impedance inversion is a key technology for pre-drilling prediction by VSP data. In this paper, based on the facts that VSP data has high resolution, high signal to noise ratio, and the downgoing and upgoing waves can be accurately separated, we propose a method of predicting the impedance below the borehole in front of the bit using VSP data. First, the method of nonlinear iterative inversion is adopted to invert for impedance using the VSP corridor stack. Then, by modifying the damping factor in the iteration and using the preconditioned conjugate gradient method to solve the equations, the stability and convergence of the inversion results can be enhanced. The results of theoretical models and actual data demonstrate that the method is effective for pre-drilling prediction using VSP data.
基金Supported by the 1.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University,No.ZYGD18025.
文摘Chronic wound healing has long been an unmet medical need in the field of wound repair,with diabetes being one of the major etiologies.Diabetic chronic wounds(DCWs),especially diabetic foot ulcers,are one of the most threatening chronic complications of diabetes.Although the treatment strategies,drugs,and dressings for DCWs have made great progress,they remain ineffective in some patients with refractory wounds.Stem cell-based therapies have achieved specific efficacy in various fields,with mesenchymal stem cells(MSCs)being the most widely used.Although MSCs have achieved good feedback in preclinical studies and clinical trials in the treatment of cutaneous wounds or other situations,the potential safety concerns associated with allogeneic/autologous stem cells and unknown long-term health effects need further attention and supervision.Recent studies have reported that stem cells mainly exert their trauma repair effects through paracrine secretion,and exosomes play an important role in intercellular communication as their main bioactive component.MSC-derived exosomes(MSC-Exos)inherit the powerful inflammation and immune modulation,angiogenesis,cell proliferation and migration promotion,oxidative stress alleviation,collagen remodeling imbalances regulation of their parental cells,and can avoid the potential risks of direct stem cell transplantation to a large extent,thus demonstrating promising performance as novel"cell-free"therapies in chronic wounds.This review aimed to elucidate the potential mechanism and update the progress of MSC-Exos in DCW healing,thereby providing new therapeutic directions for DCWs that are difficult to be cured using conventional therapy.
基金This paper was supported by the Outstanding Youth Natural Science Foundation of China(Grant No.40325016)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE,PRC(TRAPOYT)the National Natural Science Foundation of China(Grant No.40175011).
文摘The precursors of dipole blocking are obtained by a numerical approach based upon a quasi-geostrophic barotropic planetary- to synoptic-scale interaction model without topography and with a localized synoptic-scale wave-maker. The optimization problem related to the precursors of blocking is formulated and the nonlinear optimization method is used to examine the optimal synoptic-scale initial field successfully. The results show that the prominent characteristics of the optimal synoptic-scale initial field are that the synoptic-scale wave train structures exist upstream of the incipient blocking. In addition, the large-scale low/high eddy-forcing pattern upstream of the incipient blocking is an essential precondition for the onset of dipole blocking.
基金Supported by the Project of Zhengzhou Tobacco Company of Henan Province(201415)~~
文摘In the process of tobacco production, the moisture content of tobacco leaves directly affects the quality of tobacco leaf. Since the water content in the leaf is low, it needs to process with the conditioning treatment for a short time beforetobacco grading, so as to improve the tobacco moisture content and reduce breakage, as well as ensure the quality and yield of tobacco, ahd meet the requirements of the follow-up process of tobacco. Therefore, a comprehensive overview was given to the pre-conditioning method for tobacco leaf, and the current application status of tobacco leaf pre-conditioning equipment in China was explored.
文摘Changes in total polyphenols, O-diphenols and anthocyanin concentrations during fermentation and drying of pulp pre-conditioned cocoa （Theobroma cacao） beans were investigated using standard analytical methods. Increasing pod storage, fermentation and drying led to variable reductions in total polyphenols, O-diphenols and anthocyanins content of the beans. The rates of reduction were however more pronounced during fermentation than pod storage and drying. Storage of cocoa pods between 3-7 days with 6 and 7 days of fermentation and drying respectively retained 85%-90% of the total polyphenol and O-diphenols of the cocoa beans. Similarly, anthocyanin content of beans from the 10 days of pod storage decreased by 70% in the sixth day of fermentation. Pod storage decreased the anthocyanin content at all periods of fermentation. These suggest that the post-harvest treatments of pod storage, fermentation and drying all results in variable reductions in polyphenolic content （total polyphenols and O-diphenols） and anthocyanins content of cocoa beans.
文摘Ischemic heart disease (IHD) accelerates death of cardiomyocytes and leads to the onset of cardiac failure. Due to the application of stem cells, there exists a potential for the regeneration of a damaged myocardium. Here we present a brief review of the modern data on the application of various types of stem cells for the IHD therapy. We consider different types of stem cells, which are most preferable for the clinical application, including mesenchymal stem cells, cardiac stem cells, embryonic stem cells, iPS cells and others. In particular, we discuss their advantages and strategies which can be applied in order to boost their regenerative potential, as well as optimization of their delivery. Besides, our review refers to the contemporary achievements in the field of tissue engineering of heart, using both polymer scaffolds and scaffold-free constructs. We also discuss the most prominent known clinical trials on stem cell therapy of ischemic heart disease.
