Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells ...Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.展开更多
BACKGROUND Restless legs syndrome(RLS)is characterized by an urge to move with an unpleasant sensation in the lower limbs.RLS typically affects the legs.However,it can also affect several other body regions,such as th...BACKGROUND Restless legs syndrome(RLS)is characterized by an urge to move with an unpleasant sensation in the lower limbs.RLS typically affects the legs.However,it can also affect several other body regions,such as the arms,abdomen,face,neck,head,and genital area.There are only a few reports of the RLS variant affecting the head.AIM To assess the epidemiological,clinical,and other aspects of the RLS variant affecting the head.METHODS We conducted a retrospective study of 17 adult patients(>18 years)who met the RLS criteria and simultaneously experienced RLS-like symptoms in the head.RESULTS The median age at which symptoms appeared was 41.6 years.Males and females were equally affected(1.1:1).All 17 patients had uncomfortable sensations in the lower legs.Insomnia or disturbed sleep was the most common comorbidity(n=16,88.2%).However,headache was the most common presenting or primary symptom(n=10,70.5%).Dizziness or an abnormal sensation in the head was the second most common presenting symptom(5 patients,29.4%).Other presenting features were leg pain,backache,and generalized body pain.All patients responded favorably to dopaminergic medications.CONCLUSION If RLS-related unpleasant sensations and pain are felt in the head,they may be misinterpreted as headache,dizziness,or psychosomatic symptoms.RLS and headaches in a subset of patients may be two phenotypic manifestations of the same disorder.展开更多
AIM:To evaluate whether optical coherence tomography angiography(OCTA) can detect altered vessel density(VD) at the optic nerve head(ONH) in glaucoma patients.Special attention is paid to the accuracy of the OC...AIM:To evaluate whether optical coherence tomography angiography(OCTA) can detect altered vessel density(VD) at the optic nerve head(ONH) in glaucoma patients.Special attention is paid to the accuracy of the OCTA technique for distinguishing healthy from glaucomatous eyes.METHODS:A total of 171 eyes were examined by the OCTA system Angio Vue^TM(Optovue):97 eyes diagnosed with glaucoma and 74 healthy control eyes.The papillary and peripapillary VD was measured.Furthermore,the VD was correlated with different structural and functional measurements.In order to test the accuracy of differentiation between eyes with and without glaucoma,we calculated the receiver operating characteristic curve(ROC) and the area under the curve(AUC).RESULTS:The papillary and peripapillary VD in glaucomatous eyes was significantly lower than in healthy eyes(P〈0.05).The VD of the nasal peripapillary sector was significantly lower than in the other sectors.The further the disease had progressed [measured by determining the thickness of the ganglion cell complex(GCC) and the retinal nerve fiber layer(RNFL)] the greater the VD reduction.The AUC discriminated well between glaucomatous and normal eyes(consensus classifier 94.2%).CONCLUSION:OCTA allows non-invasive quantification of the peripapillary and papillary VD,which is significantly reduced in glaucomatous eyes and accurately distinguishes between healthy and diseased eyes.OCTA expands the spectrum of procedures for detecting and monitoring glaucoma.展开更多
The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head (ANFH). The rabbit model of the ANFH is established. The histopathologic featu...The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head (ANFH). The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroidinjection group (S.G.) and the controlled group (C.G.) are examined, including the weight of rabbits, the hematological examination and the three-dimensional stnactures. It is found that the plasma levels of cholesterol (CHO), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in S.G. are lower than those in C.G. when the triglyceride (TG) increased in the S.G.; but the bone mineral content (BMC) and the structural model index (SMI) of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography (CT) scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.展开更多
As an important part of future 5G wireless networks,a vehicular network demands safety,reliability and connectivity.In this context,networking survivability is usually considered an important metric to evaluate networ...As an important part of future 5G wireless networks,a vehicular network demands safety,reliability and connectivity.In this context,networking survivability is usually considered an important metric to evaluate network performance.In this paper,we propose a survivability model for vehicle communication networking based on dual cluster heads,wherein a backup cluster head(CH)will be activated if the primary CH fails,thereby effectively enhancing the network lifetime.Additionally,we introduce a software rejuvenation strategy for the prime CH to further improve the survivability of the entire network.Using the Probabilistic Symbolic Model Checker(PRISM),we verify and discuss the proposed survivability model via numerical simulations.The results show that network survivability can be effectively improved by introducing an additional CH and further enhanced by adopting the software rejuvenation technique.展开更多
The demands for improved fuel economy,performance and emissions continue to pose challenges for engine designers and the materials they choose. This is particularly true for modern diesel engines,where the primary pat...The demands for improved fuel economy,performance and emissions continue to pose challenges for engine designers and the materials they choose. This is particularly true for modern diesel engines,where the primary path to achieving improved engine performance and emissions is to increase the Peak Firing Pressure in the combustion chamber. The resulting increase in thermal and mechanical loading has required a change from conventional grey cast iron to Compacted Graphite Iron (CGI) in order to satisfy durability requirements without increasing the size or the weight of the engines. With at least 75% higher tensile strength,45% higher stiffness and approximately double the fatigue strength of conventional grey cast iron,CGI satisfies durability requirements and also provides the dimensional stability required to meet emissions legislation throughout the life of the engine. Currently,there are no CGI diesel engines running on the roads in North America. This is set to change considerably as new commercial vehicle and pick-up SUV diesel engines are launched with CGI cylinder blocks in 2008 and 2009. These initial programs will provide over 2 million CGI diesel engines when ramped to mature volume,potentially accounting for 10%-15% of the North American passenger vehicle fleet within the next four years.展开更多
Inflorescences in the Asteraceae plant family,flower heads,or capitula,mimic single flowers but are highly compressed structures composed of multiple flowers.This transference of a flower-like appearance into an inflo...Inflorescences in the Asteraceae plant family,flower heads,or capitula,mimic single flowers but are highly compressed structures composed of multiple flowers.This transference of a flower-like appearance into an inflorescence level is considered as the key innovation for the rapid tribal radiation of Asteraceae.Recent molecular data indicate that Asteraceae flower heads resemble single flowers not only morphologically but also at molecular level.We summarize this data giving examples of how rewiring of conserved floral regulators have led to evolution of morphological innovations in Asteraceae.Functional diversification of the highly conserved flower meristem identity regulator LEAFY has shown a major role in the evolution of the capitulum architecture.Furthermore,gene duplication and subsequent sub-and neofunctionalization of SEPALLATA-and CYCLOIDEA-like genes in Asteraceae have been shown to contribute to meristem determinacy,as well as flower type differentiation—key traits that specify this large family.Future challenge is to integrate genomic,as well as evolutionary developmental studies in a wider selection of Asteraceae species to understand the detailed gene regulatory networks behind the elaborate inflorescence architecture,and to promote our understanding of how changes in regulatory mechanisms shape development.展开更多
This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,proce...This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,processing time and delivery time first rule is designed to determine a certain machine for each job,and the largest difference between delivery time and release date first rule is designed to sequence the jobs scheduled on the same machine,and then a novel algorithm for the scheduling problem is built.To evaluate the performance of the proposed algorithm,a lower bound for the problem is proposed.The accuracy of the proposed algorithm is tested based on the data with problem size varying from 200 jobs to 600 jobs.The computational results indicate that the average relative error between the proposed algorithm and the lower bound is only 0.667%,therefore the solutions obtained by the proposed algorithm are very accurate.展开更多
The effects of AITi5B1 grain refinement and cooling rate on the microstructure and mechanical properties of a secondary AlSi7Cu3Mg alloy were reported. Metallographic and image analysis techniques have been used to qu...The effects of AITi5B1 grain refinement and cooling rate on the microstructure and mechanical properties of a secondary AlSi7Cu3Mg alloy were reported. Metallographic and image analysis techniques have been used to quantitatively examine the macrostructural and microstructural changes occurring with the addition of grain-refining agent at different cooling rates by using a step casting die. The results indicate that the addition of AlTi5B1 produces a fine and uniform grain structure throughout the casting and this effect is more pronounced in the slowly solidified regions. Increasing the cooling rate, lower amount of grain refiner is necessary to produce a uniform grain size throughout the casting. On the other hand, the initial contents of Ti and B, present as impurity elements in the supplied secondary alloy, are not sufficient to produce an effective grain refinement. The results from the step casting geometry were applied to investigate a gasoline 16V cylinder head, which was produced by gravity semi-permanent mould technology. The grain refinement improves the plastic behaviour of the alloy and increases the reliability of the casting, as evidenced by the Weibull statistics.展开更多
For the purpose of solving the problem that too large pole tip recession (PTR) is produced in magnetic rigid disk heads by mechanical polishing, a chemical mechanical nano-grinding experiment is performed by using a...For the purpose of solving the problem that too large pole tip recession (PTR) is produced in magnetic rigid disk heads by mechanical polishing, a chemical mechanical nano-grinding experiment is performed by using a float-piece polisher with a tin plate to achieve a more plane and smoother surface. A basal solution, addition agents and a range of pH value are suitably selected to find a kind of slurry, with which the PTR can be controlled on sub-nanometer scale and the giant magnetic resistance (GMR) corrosion and electrostatic damage (ESD) can be avoided. Moreover, the cause that TiC protrudes from the substrate surface of the heads is studied. The appropriate shape and size of diamond abrasive are selected according to the chemical activation of A1203 and TiC in the same slurry. In this way, the chemical and mechanical interactions are optimized and the optimal surface that has small PTR and TiC asperity is achieved. Ultimatily, the chemical mechanical nano-grinding in combination with mechanical nano-grinding is adopted. Sub-nanometer PTR is achieved and the TiC asperity is eliminated by the chemical mechanical nano-grinding with large size ofmonocrystalline followed by mechanical nano-grinding with smalle polycrystalline diamonds.展开更多
Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regen...Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement.However,the neural regeneration efficiency of induced neural stem cells remains limited.In this study,we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells.We found that H19 was the most downregulated neurogenesis-associated lnc RNA in induced neural stem cells compared with induced pluripotent stem cells.Additionally,we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons.We predicted the target genes of H19 and discovered that H19 directly interacts with mi R-325-3p,which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells.Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation,and mi R-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition.Furthermore,H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells.Notably,silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice.Our results reveal that H19 regulates the neurogenesis of induced neural stem cells.H19 inhibition may promote the neural differentiation of induced neural stem cells,which is closely associated with neurological recovery following closed head injury.展开更多
Background: Breast cancer (BC) is one of the malignant diseases taking the lion’s share role in the devastating effects caused by cancer. BC related awareness and practice of females are known to have crucial contrib...Background: Breast cancer (BC) is one of the malignant diseases taking the lion’s share role in the devastating effects caused by cancer. BC related awareness and practice of females are known to have crucial contribution in the prevention and control efforts. The worst aspects of the disease in Ethiopia include absence of research and thus very limited information on any aspect. The study assessed knowledge and practice on BC among women household heads. Methods: A cross-sectional study was conducted on a sample of 845 women. The sample size was divided among five randomly selected kebeles (smallest government administrative units) proportional to the number of households. Samples were selected by systematic sampling technique. Data were collected by trained data collectors through a face-to-face interview using pre-tested, semi-structured questionnaire from female household heads. Pearson chi-square and logistic regression tests were used to assess the determinants of BC knowledge and breast cancer self examination (BSE) practice. Results: The respondents’ age ranged from 20 to 75 years with a mean age of 33.66 ± 10.8. Onefifth (19.8%) of the respondents were illiterate, while 257 (31.8%) had primary education. Majority of them were married 548 (67.7%), Orthodox Christians 649 (80.4%), and housewives 365 (45.1%). Only 675 (83.4%) of the respondents have ever heard/read about BC. Media 399 (59.1%) and colleagues/friends/neighbors 200 (29.6%) were the major information sources. Only 86 (12.7%) of the respondents had a high BC knowledge. Even though 304 (45%) of the BC informed participants had information on BSE, only 163 (53.6%) of them have ever done it. Both BC knowledge and BSE practice were significantly affected by educational level. Conclusion: Majority of women household heads in Mekelle town had low knowledge and insufficient BC related practices. The region’s health bureau and local mass-media need to work on breast cancer awareness and practice of the women in the town.展开更多
“Locked twins” is a rare event occurring in about 1 in every 1000 twin births. A 21-year-old primigravida with a 31-week twin pregnancy was admitted for delivery. The head of the first twin was locked to the chin of...“Locked twins” is a rare event occurring in about 1 in every 1000 twin births. A 21-year-old primigravida with a 31-week twin pregnancy was admitted for delivery. The head of the first twin was locked to the chin of the second twin at the top of the symphysis pubis. Caesarean section was performed allowing the delivery of both dead twins. Twins gestations with first twin in the breech </span><span style="font-family:Verdana;">presentation raise index of suspicion of potential locked twin. However,</span><span style="font-family:Verdana;"> management of such situation is controversial with most authors and colleges re</span><span style="font-family:Verdana;">commending caesarean section to avoid interlocking heads. We report</span><span style="font-family:Verdana;"> another rare case of interlocking heads and bring up the topic about management of breech-first twin deliveries.展开更多
As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this...As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this paper,a cooperative security monitoring mechanism aided by multiple slave cluster heads(SCHs)is proposed to keep track of the data security of a CH.By designing a low complexity“equilateral triangle algorithm(ETA)”,the optimal SCHs(named as ETA-based multiple SCHs)are selected from the candidate SCHs so as to improve the dispersion and coverage of SCHs and achieve largescale data security monitoring.In addition,by analyzing the entire monitoring process,the close form expression of the probability of the failure attack identification for the SCHs with respect to the probability of attack launched by ordinary nodes is deduced.The simulation results show that the proposed optimal ETA-based multiple SCH cooperation scheme has lower probability of the failure attack identification than that of the existing schemes.In addition,the numerical simulation results are consistent with the theoretical analysis results,thus verifying the effectiveness of the proposed scheme.展开更多
AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-thre...AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-three healthy subjects were enrolled.The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm×3 mm scanning protocol.Images of the radial peripapillary capillary were analyzed by a customized Matlab program,and the vessel density,fractal dimension,and vessel diameter index were measured.The repeatability of the four scans was determined by the intraclass correlation coefficient(ICC).The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient,ICC and Bland-Altman plots.RESULTS:All swept-source-OCTA ONH parameters exhibited certain repeatability,with ICC>0.760 and coefficient of variation(CoV)≤7.301%.The obvious interocular correlation was observed for papillary vessel density(ICC=0.857),vessel diameter index(ICC=0.857)and fractal dimension(ICC=0.906),while circumpapillary vessel density exhibited moderate interocular correlation(ICC=0.687).Bland-Altman plots revealed an agreement range of-5.26%to 6.21%for circumpapillary vessel density.CONCLUSION:OCTA ONH parameters demonstrate good repeatability in healthy subjects.The interocular correlations of papillary vessel density,fractal dimension and vessel diameter index are high,but the correlation for circumpapillary vessel density is moderate.展开更多
It was early spring in 1985.I was watching a local opera on the village’s Willow Stage.Mom spotted me among the crowd and dragged me out.At that moment,the last thing I wanted to do was leave.While mom tugged at my b...It was early spring in 1985.I was watching a local opera on the village’s Willow Stage.Mom spotted me among the crowd and dragged me out.At that moment,the last thing I wanted to do was leave.While mom tugged at my black cotton-wadded coat,I struggled to resist,all the while trying to still catch a glimpse of the opera.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82271397(to MG),82001293(to MG),82171355(to RX),81971295(to RX),and 81671189(to RX)。
文摘Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.
文摘BACKGROUND Restless legs syndrome(RLS)is characterized by an urge to move with an unpleasant sensation in the lower limbs.RLS typically affects the legs.However,it can also affect several other body regions,such as the arms,abdomen,face,neck,head,and genital area.There are only a few reports of the RLS variant affecting the head.AIM To assess the epidemiological,clinical,and other aspects of the RLS variant affecting the head.METHODS We conducted a retrospective study of 17 adult patients(>18 years)who met the RLS criteria and simultaneously experienced RLS-like symptoms in the head.RESULTS The median age at which symptoms appeared was 41.6 years.Males and females were equally affected(1.1:1).All 17 patients had uncomfortable sensations in the lower legs.Insomnia or disturbed sleep was the most common comorbidity(n=16,88.2%).However,headache was the most common presenting or primary symptom(n=10,70.5%).Dizziness or an abnormal sensation in the head was the second most common presenting symptom(5 patients,29.4%).Other presenting features were leg pain,backache,and generalized body pain.All patients responded favorably to dopaminergic medications.CONCLUSION If RLS-related unpleasant sensations and pain are felt in the head,they may be misinterpreted as headache,dizziness,or psychosomatic symptoms.RLS and headaches in a subset of patients may be two phenotypic manifestations of the same disorder.
文摘AIM:To evaluate whether optical coherence tomography angiography(OCTA) can detect altered vessel density(VD) at the optic nerve head(ONH) in glaucoma patients.Special attention is paid to the accuracy of the OCTA technique for distinguishing healthy from glaucomatous eyes.METHODS:A total of 171 eyes were examined by the OCTA system Angio Vue^TM(Optovue):97 eyes diagnosed with glaucoma and 74 healthy control eyes.The papillary and peripapillary VD was measured.Furthermore,the VD was correlated with different structural and functional measurements.In order to test the accuracy of differentiation between eyes with and without glaucoma,we calculated the receiver operating characteristic curve(ROC) and the area under the curve(AUC).RESULTS:The papillary and peripapillary VD in glaucomatous eyes was significantly lower than in healthy eyes(P〈0.05).The VD of the nasal peripapillary sector was significantly lower than in the other sectors.The further the disease had progressed [measured by determining the thickness of the ganglion cell complex(GCC) and the retinal nerve fiber layer(RNFL)] the greater the VD reduction.The AUC discriminated well between glaucomatous and normal eyes(consensus classifier 94.2%).CONCLUSION:OCTA allows non-invasive quantification of the peripapillary and papillary VD,which is significantly reduced in glaucomatous eyes and accurately distinguishes between healthy and diseased eyes.OCTA expands the spectrum of procedures for detecting and monitoring glaucoma.
基金supported by the National Natural Science Foundation of China(30470430 and 30400514)
文摘The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head (ANFH). The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroidinjection group (S.G.) and the controlled group (C.G.) are examined, including the weight of rabbits, the hematological examination and the three-dimensional stnactures. It is found that the plasma levels of cholesterol (CHO), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in S.G. are lower than those in C.G. when the triglyceride (TG) increased in the S.G.; but the bone mineral content (BMC) and the structural model index (SMI) of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography (CT) scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.
基金supported by the National Natural Science Foundation of China (No. 61971245 and 61801249 )Nantong University-Nantong Joint Research Center for Intelligent Information Technology (No. KFKT2016A01)
文摘As an important part of future 5G wireless networks,a vehicular network demands safety,reliability and connectivity.In this context,networking survivability is usually considered an important metric to evaluate network performance.In this paper,we propose a survivability model for vehicle communication networking based on dual cluster heads,wherein a backup cluster head(CH)will be activated if the primary CH fails,thereby effectively enhancing the network lifetime.Additionally,we introduce a software rejuvenation strategy for the prime CH to further improve the survivability of the entire network.Using the Probabilistic Symbolic Model Checker(PRISM),we verify and discuss the proposed survivability model via numerical simulations.The results show that network survivability can be effectively improved by introducing an additional CH and further enhanced by adopting the software rejuvenation technique.
文摘The demands for improved fuel economy,performance and emissions continue to pose challenges for engine designers and the materials they choose. This is particularly true for modern diesel engines,where the primary path to achieving improved engine performance and emissions is to increase the Peak Firing Pressure in the combustion chamber. The resulting increase in thermal and mechanical loading has required a change from conventional grey cast iron to Compacted Graphite Iron (CGI) in order to satisfy durability requirements without increasing the size or the weight of the engines. With at least 75% higher tensile strength,45% higher stiffness and approximately double the fatigue strength of conventional grey cast iron,CGI satisfies durability requirements and also provides the dimensional stability required to meet emissions legislation throughout the life of the engine. Currently,there are no CGI diesel engines running on the roads in North America. This is set to change considerably as new commercial vehicle and pick-up SUV diesel engines are launched with CGI cylinder blocks in 2008 and 2009. These initial programs will provide over 2 million CGI diesel engines when ramped to mature volume,potentially accounting for 10%-15% of the North American passenger vehicle fleet within the next four years.
基金This work has been funded by the Academy of Finland grants for P.E.(11390921310318)Jenny and Antti Wihuri Foundation for Y.Z.and Doctoral Programme in Plant Sciences for Y.Z.and T.Z.
文摘Inflorescences in the Asteraceae plant family,flower heads,or capitula,mimic single flowers but are highly compressed structures composed of multiple flowers.This transference of a flower-like appearance into an inflorescence level is considered as the key innovation for the rapid tribal radiation of Asteraceae.Recent molecular data indicate that Asteraceae flower heads resemble single flowers not only morphologically but also at molecular level.We summarize this data giving examples of how rewiring of conserved floral regulators have led to evolution of morphological innovations in Asteraceae.Functional diversification of the highly conserved flower meristem identity regulator LEAFY has shown a major role in the evolution of the capitulum architecture.Furthermore,gene duplication and subsequent sub-and neofunctionalization of SEPALLATA-and CYCLOIDEA-like genes in Asteraceae have been shown to contribute to meristem determinacy,as well as flower type differentiation—key traits that specify this large family.Future challenge is to integrate genomic,as well as evolutionary developmental studies in a wider selection of Asteraceae species to understand the detailed gene regulatory networks behind the elaborate inflorescence architecture,and to promote our understanding of how changes in regulatory mechanisms shape development.
基金supported by the National Natural Science Foundation of China (7087103290924021+2 种基金70971035)the National High Technology Research and Development Program of China (863 Program) (2008AA042901)Anhui Provincial Natural Science Foundation (11040606Q27)
文摘This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,processing time and delivery time first rule is designed to determine a certain machine for each job,and the largest difference between delivery time and release date first rule is designed to sequence the jobs scheduled on the same machine,and then a novel algorithm for the scheduling problem is built.To evaluate the performance of the proposed algorithm,a lower bound for the problem is proposed.The accuracy of the proposed algorithm is tested based on the data with problem size varying from 200 jobs to 600 jobs.The computational results indicate that the average relative error between the proposed algorithm and the lower bound is only 0.667%,therefore the solutions obtained by the proposed algorithm are very accurate.
文摘The effects of AITi5B1 grain refinement and cooling rate on the microstructure and mechanical properties of a secondary AlSi7Cu3Mg alloy were reported. Metallographic and image analysis techniques have been used to quantitatively examine the macrostructural and microstructural changes occurring with the addition of grain-refining agent at different cooling rates by using a step casting die. The results indicate that the addition of AlTi5B1 produces a fine and uniform grain structure throughout the casting and this effect is more pronounced in the slowly solidified regions. Increasing the cooling rate, lower amount of grain refiner is necessary to produce a uniform grain size throughout the casting. On the other hand, the initial contents of Ti and B, present as impurity elements in the supplied secondary alloy, are not sufficient to produce an effective grain refinement. The results from the step casting geometry were applied to investigate a gasoline 16V cylinder head, which was produced by gravity semi-permanent mould technology. The grain refinement improves the plastic behaviour of the alloy and increases the reliability of the casting, as evidenced by the Weibull statistics.
基金National Natural Science Foundation of China(No. 50390061).
文摘For the purpose of solving the problem that too large pole tip recession (PTR) is produced in magnetic rigid disk heads by mechanical polishing, a chemical mechanical nano-grinding experiment is performed by using a float-piece polisher with a tin plate to achieve a more plane and smoother surface. A basal solution, addition agents and a range of pH value are suitably selected to find a kind of slurry, with which the PTR can be controlled on sub-nanometer scale and the giant magnetic resistance (GMR) corrosion and electrostatic damage (ESD) can be avoided. Moreover, the cause that TiC protrudes from the substrate surface of the heads is studied. The appropriate shape and size of diamond abrasive are selected according to the chemical activation of A1203 and TiC in the same slurry. In this way, the chemical and mechanical interactions are optimized and the optimal surface that has small PTR and TiC asperity is achieved. Ultimatily, the chemical mechanical nano-grinding in combination with mechanical nano-grinding is adopted. Sub-nanometer PTR is achieved and the TiC asperity is eliminated by the chemical mechanical nano-grinding with large size ofmonocrystalline followed by mechanical nano-grinding with smalle polycrystalline diamonds.
基金supported by the National Natural Science Foundation of China,Nos.82271397(to MG),82001293(to MG),82171355(to RX),81971295(to RX)and 81671189(to RX)。
文摘Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement.However,the neural regeneration efficiency of induced neural stem cells remains limited.In this study,we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells.We found that H19 was the most downregulated neurogenesis-associated lnc RNA in induced neural stem cells compared with induced pluripotent stem cells.Additionally,we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons.We predicted the target genes of H19 and discovered that H19 directly interacts with mi R-325-3p,which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells.Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation,and mi R-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition.Furthermore,H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells.Notably,silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice.Our results reveal that H19 regulates the neurogenesis of induced neural stem cells.H19 inhibition may promote the neural differentiation of induced neural stem cells,which is closely associated with neurological recovery following closed head injury.
文摘Background: Breast cancer (BC) is one of the malignant diseases taking the lion’s share role in the devastating effects caused by cancer. BC related awareness and practice of females are known to have crucial contribution in the prevention and control efforts. The worst aspects of the disease in Ethiopia include absence of research and thus very limited information on any aspect. The study assessed knowledge and practice on BC among women household heads. Methods: A cross-sectional study was conducted on a sample of 845 women. The sample size was divided among five randomly selected kebeles (smallest government administrative units) proportional to the number of households. Samples were selected by systematic sampling technique. Data were collected by trained data collectors through a face-to-face interview using pre-tested, semi-structured questionnaire from female household heads. Pearson chi-square and logistic regression tests were used to assess the determinants of BC knowledge and breast cancer self examination (BSE) practice. Results: The respondents’ age ranged from 20 to 75 years with a mean age of 33.66 ± 10.8. Onefifth (19.8%) of the respondents were illiterate, while 257 (31.8%) had primary education. Majority of them were married 548 (67.7%), Orthodox Christians 649 (80.4%), and housewives 365 (45.1%). Only 675 (83.4%) of the respondents have ever heard/read about BC. Media 399 (59.1%) and colleagues/friends/neighbors 200 (29.6%) were the major information sources. Only 86 (12.7%) of the respondents had a high BC knowledge. Even though 304 (45%) of the BC informed participants had information on BSE, only 163 (53.6%) of them have ever done it. Both BC knowledge and BSE practice were significantly affected by educational level. Conclusion: Majority of women household heads in Mekelle town had low knowledge and insufficient BC related practices. The region’s health bureau and local mass-media need to work on breast cancer awareness and practice of the women in the town.
文摘“Locked twins” is a rare event occurring in about 1 in every 1000 twin births. A 21-year-old primigravida with a 31-week twin pregnancy was admitted for delivery. The head of the first twin was locked to the chin of the second twin at the top of the symphysis pubis. Caesarean section was performed allowing the delivery of both dead twins. Twins gestations with first twin in the breech </span><span style="font-family:Verdana;">presentation raise index of suspicion of potential locked twin. However,</span><span style="font-family:Verdana;"> management of such situation is controversial with most authors and colleges re</span><span style="font-family:Verdana;">commending caesarean section to avoid interlocking heads. We report</span><span style="font-family:Verdana;"> another rare case of interlocking heads and bring up the topic about management of breech-first twin deliveries.
基金supported in part by the Joint Fund of Science and Technology Department of Liaoning Province and State Key Laboratory of Robotics,China under Grant 2021-KF-22-08in part by the Basic Research Program of Science and Technology of Shenzhen,China under Grant JCYJ20190809161805508in part by the National Natural Science Foundation of China under Grant 62271423 and Grant 41976178.
文摘As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this paper,a cooperative security monitoring mechanism aided by multiple slave cluster heads(SCHs)is proposed to keep track of the data security of a CH.By designing a low complexity“equilateral triangle algorithm(ETA)”,the optimal SCHs(named as ETA-based multiple SCHs)are selected from the candidate SCHs so as to improve the dispersion and coverage of SCHs and achieve largescale data security monitoring.In addition,by analyzing the entire monitoring process,the close form expression of the probability of the failure attack identification for the SCHs with respect to the probability of attack launched by ordinary nodes is deduced.The simulation results show that the proposed optimal ETA-based multiple SCH cooperation scheme has lower probability of the failure attack identification than that of the existing schemes.In addition,the numerical simulation results are consistent with the theoretical analysis results,thus verifying the effectiveness of the proposed scheme.
基金Natural Science Foundation of Guangdong Province(No.2018A0303130306)Shantou Science and Technology Program(No.190917085269835,No.200629165261641).
文摘AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-three healthy subjects were enrolled.The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm×3 mm scanning protocol.Images of the radial peripapillary capillary were analyzed by a customized Matlab program,and the vessel density,fractal dimension,and vessel diameter index were measured.The repeatability of the four scans was determined by the intraclass correlation coefficient(ICC).The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient,ICC and Bland-Altman plots.RESULTS:All swept-source-OCTA ONH parameters exhibited certain repeatability,with ICC>0.760 and coefficient of variation(CoV)≤7.301%.The obvious interocular correlation was observed for papillary vessel density(ICC=0.857),vessel diameter index(ICC=0.857)and fractal dimension(ICC=0.906),while circumpapillary vessel density exhibited moderate interocular correlation(ICC=0.687).Bland-Altman plots revealed an agreement range of-5.26%to 6.21%for circumpapillary vessel density.CONCLUSION:OCTA ONH parameters demonstrate good repeatability in healthy subjects.The interocular correlations of papillary vessel density,fractal dimension and vessel diameter index are high,but the correlation for circumpapillary vessel density is moderate.
文摘It was early spring in 1985.I was watching a local opera on the village’s Willow Stage.Mom spotted me among the crowd and dragged me out.At that moment,the last thing I wanted to do was leave.While mom tugged at my black cotton-wadded coat,I struggled to resist,all the while trying to still catch a glimpse of the opera.