The effect of H2S concentration on H2S/CO2 corrosion of API-X60 steel was studied by scanning electron microscopy, a weight-loss method, potentiodynamic polarization tests, and the electrochemical impedance spectrosco...The effect of H2S concentration on H2S/CO2 corrosion of API-X60 steel was studied by scanning electron microscopy, a weight-loss method, potentiodynamic polarization tests, and the electrochemical impedance spectroscopy technique. It is found that the cor-rosion process of the steel in an environment where H2S and CO2 coexist at different H2S concentrations is related to the morphological structure and stability of the corrosion product film. With the addition of a small amount of H2S, the size of the anode reaction region is de-creased due to constant adsorption and separation of more FeS sediment or more FeHS+ions on the surface of the steel. Meanwhile, the dou-ble-layer capacitance is diminished with increasing anion adsorption capacity. Therefore, the corrosion process is inhibited. The general cor-rosion rate of the steel rapidly decreases after the addition of a small amount of H2S under the coexistence of H2S and CO2. With a further increase in H2S concentration, certain parts of the corrosion product film become loose and even fall off. Thus, the protection provided by the corrosion product film worsens, and the corrosion rate tends to increase.展开更多
Recently,continuous breakthroughs have been made about deep gold prospecting in the Jiaodong gold province area of China.Approximately 5000 t of cumulative gold resources have been explored in Jiaodong,which has thus ...Recently,continuous breakthroughs have been made about deep gold prospecting in the Jiaodong gold province area of China.Approximately 5000 t of cumulative gold resources have been explored in Jiaodong,which has thus become an internationally noteworthy gold ore cluster.The gold exploration depth has been increased to about 2000 m from the previous<1000 m.To further explore the mineralization potential of the Jiaodong area at a depth of about 3000 m,the Shandong Institute of Geological Sciences has drilled an exploratory drillhole named“Deep drillhole ZK01”to a depth of 3266 m.Hence,as reported herein,the mineralization characteristics of the Jiaojia metallogenic belt have been successfully documented.ZK01 is,to date,the deepest borehole with an gold intersect in China,and constitutes a significant advance in deep gold prospecting in China.The findings of this study further indicate that the depth interval of 2000 m to 4000 m below the ground surface in the Wuyi Village area incorporates 912 t of inferred gold resources,while the depth interval of 2000 m to 4000 m below the surface across the Jiaodong area possesses about 4000 t of inferred gold resources.The Jiaojia Fault Belt tends to gently dip downward,having dip angles of about 25°and about 20°at vertical depths of 2000 m and 2850 m,respectively.The deep part of the Jiaojia metallogenic belt differs from the shallow and moderately deep parts about fracturing,alteration,mineralization,and tectonic type.The deep zones can generally be categorized from inside outward as cataclastic granite,granitic cataclasite,weakly beresitized granitic cataclasite,beresitized cataclasite,and gouge.These zones exhibit a gradual transitional relation or occur alternately and repeatedly.The mineralization degree of the pyritized cataclastic granite-type ore in the deep part of the Jiaojia metallogenic belt is closely related to the degree of pyrite vein development;that is,the higher the pyrite content,the wider the veins and the higher the gold grade.Compared to the shallow gold ores,the deep-seated gold ores have higher fineness and contain joseite,tetradymite,and native bismuth,suggesting that the deep gold mineralization temperature is higher and that mantle-sourced material may have contributed to this mineralization.ZK01 has also revealed that the deep-seated ore bodies in the Jiaojia metallogenic belt are principally situated above the main fracture plane(gouge)and hosted within the Linglong Granite,contradicting previous findings indicating that the moderately shallow gold ore bodies are usually hosted in the contact zone between the Linglong Granite and Jiaodong Group or meta-gabbro.These new discoveries are particularly significant because they can help correct mineralization prospecting models,determine favorable positions for deep prospecting,and improve metallogenic prediction and resource potential evaluation.展开更多
BACKGROUND Epithelioid trophoblastic tumor(ETT) is the rarest type of gestational trophoblastic tumor(GTT). It has been reported that more than 50% of ETTs arise in the uterine cervix or the lower uterine segment. Her...BACKGROUND Epithelioid trophoblastic tumor(ETT) is the rarest type of gestational trophoblastic tumor(GTT). It has been reported that more than 50% of ETTs arise in the uterine cervix or the lower uterine segment. Here, we report a case of ETT within the lower uterine segment and cervical canal and discuss its manifestations,possible causes, and related influencing factors.CASE SUMMARY A 35-year-old woman(gravida 7, miscarriage 3, induction 2 with 1 being twins,para 2 of cesarean section, live 2), who had amenorrhea for 9 mo after breastfeeding for 22 mo after the last cesarean section, was diagnosed with ETT. The lesion was present in the lower uterine segment and endocervical canal with severe involvement of the anterior wall of the lower uterine segment and the front wall of the lower uterine segment where the cesarean incisions were made.Laboratory tests showed slight elevation of serum beta-human chorionic gonadotropin. Intraoperative exploration showed the presence of a normal-sized uterus body with an enlarged tumor in the lower uterine segment. The surface of the lower uterine segment was light blue, the entire lesion was approximately about 8cm × 8 cm × 9 cm, with compression and displacement of the surrounding tissue.Histological examination diagnosed ETT. Immunohistochemical analysis showed positive expression of p63, with a Ki-67 proliferation index of 40%.CONCLUSION A search of the PubMed database using the search terms "cesarean section" and "epithelioid trophoblastic tumor" retrieved nine articles, including 13 cases of ETT and ETT-related lesions, all 13 cases had a history of cesarean section, and the lesions were all located at the cesarean section incision on the anterior wall of the lower uterine segment. The present case is the 14th reported case of ETT after cesarean section. Therefore, we deduced that cesarean section trauma had an important effect on the occurrence of ETT at this site.展开更多
BACKGROUND Hourglass-like constriction neuropathy is a rare neurological disorder.The main clinical manifestation is peripheral nerve injury with no apparent cause,and the pathomorphological change is an unexplained n...BACKGROUND Hourglass-like constriction neuropathy is a rare neurological disorder.The main clinical manifestation is peripheral nerve injury with no apparent cause,and the pathomorphological change is an unexplained narrowing of the diseased nerve.The diagnosis and treatment of the disease are challenging and there is no accepted diagnostic or therapeutic approach.CASE SUMMARY This report describes a rare hourglass constriction of the anterior interosseous nerve in the left forearm in a 47-year-old healthy male who was treated surgically and gradually recovered function over a 6-mo follow-up period.CONCLUSION Hourglass-like constriction neuropathy is a rare disorder.With the development of medical technology,more examinations are now available for diagnosis.This case aims to highlight the rare manifestations of Hourglass-like constriction neuropathy and provides a reference for enriching the clinical diagnosis and treatment experience.展开更多
Objective:To explore the effect of partial body weight support training (PBWST) on the cardiac function, neuroendocrine function, and vascular endothelial function in patients with early heart failure.Methods: A total...Objective:To explore the effect of partial body weight support training (PBWST) on the cardiac function, neuroendocrine function, and vascular endothelial function in patients with early heart failure.Methods: A total of 98 patients with early heart failure who were admitted in our hospital were included in the study and randomized into the observation group and the control group. The patients in the control group were given routine drugs and rehabilitation. On this basis, the patients in the observation group were given PBWST. The patients in the two groups were treated for 3 months. The changes of cardiac function, neuroendocrine function, and vascular endothelial function indicators before and after rehabilitation in the two groups were detected.Results: LVESD and ESV after training in the two groups were significantly reduced. LVESD and ESV after training in the observation group were significantly lower than those in the control group. SV, CI, LVEF, and FS after training in the observation group were significantly elevated when compared with before training. LVEF and FS after training in the observation group were significantly higher than those in the control group. LVEF after training in the control group was significantly elevated. PRA, AngⅡ, ET, and ALD levels after training in the observation group were significantly reduced, while NO was significantly elevated, and the improvement of the above indicators was significantly superior to that in the control group.Conclusions: PBWST can improve the cardiac function in patients with early heart failure, inhibit the excessive activation of neuroendocrine system, and protect the vascular endothelial function in order to enhance the clinical efficacy.展开更多
Exploring the relationship between different structure of the spinal cord and functional assessment after spinal cord injury is important. Quantitative diffusion tensor imaging can provide information about the micros...Exploring the relationship between different structure of the spinal cord and functional assessment after spinal cord injury is important. Quantitative diffusion tensor imaging can provide information about the microstructure of nerve tissue and can quantify the pathological damage of spinal cord white matter and gray matter. In this study, a custom-designed spinal cord contusion-impactor was used to damage the T_(10) spinal cord of beagles. Diffusion tensor imaging was used to observe changes in the whole spinal cord, white matter, and gray matter, and the Texas Spinal Cord Injury Score was used to assess changes in neurological function at 3 hours, 24 hours, 6 weeks, and 12 weeks after injury. With time, fractional anisotropy values after spinal cord injury showed a downward trend, and the apparent diffusion coefficient, mean diffusivity, and radial diffusivity first decreased and then increased. The apparent diffusion-coefficient value was highly associated with the Texas Spinal Cord Injury Score for the whole spinal cord(R = 0.919, P = 0.027), white matter(R = 0.932, P = 0.021), and gray matter(R = 0.882, P = 0.048). Additionally, the other parameters had almost no correlation with the score(P 〉 0.05). In conclusion, the highest and most significant correlation between diffusion parameters and neurological function was the apparent diffusion-coefficient value for white matter, indicating that it could be used to predict the recovery of neurological function accurately after spinal cord injury.展开更多
Objective:To investigate the expression of targeting protein for Xenopus kinesin-like protein 2(TPX2) in breast cancer tissue and to explore its role in proliferation,migration and invasion of breast cancer cells.Meth...Objective:To investigate the expression of targeting protein for Xenopus kinesin-like protein 2(TPX2) in breast cancer tissue and to explore its role in proliferation,migration and invasion of breast cancer cells.Methods:The mRNA and protein expressions of TPX2 in breast cancer tissue and cell lines were assessed by quantitative RT-PCR and Western blot.The effect of TPX2 with RNA interference on proliferation,invasion and migration of breast cancer cells was observed by MTT and Transwell assays.Results:Both mRNA and protein expressions of TPX2 were upregulated in breast cancer tissues compared to tumor-adjacent tissue.TPX2 expression was also upregulated in breast cancer cell lines,and the TPX2 interfered by small interfering RNA could inhibit the proliferation,invasion and migration of breast cancer cells by inhibiting matrix metalloproteinase-2 and matrix metalloproteinase-9.Conclusions:Significantly upregulated TPX2 expression is observed in breast cancer tissue and cells,and contributes to promote the proliferation,migration and invasion of breast cancer cells.展开更多
Herein, the effect of high chloride ion(Cl^-) concentration on the corrosion behavior and passive film breakdown of 13Cr martensitic stainless steel under CO_2 environment was demonstrated. The Cl^- concentration was ...Herein, the effect of high chloride ion(Cl^-) concentration on the corrosion behavior and passive film breakdown of 13Cr martensitic stainless steel under CO_2 environment was demonstrated. The Cl^- concentration was varied from 30 to 150 g/L and cyclic potentiodynamic polarization was conducted to investigate the influence of the Cl^- concentration on the corrosion potential(E_(corr)), passive breakdown potential(E_(pit)), and repassivation potential(E_(rep)). The results of the polarization curves revealed that 13Cr stainless steel is susceptible to pitting under high Cl^- concentration. The passive breakdown potential and repassivation potential decreased with the increase of Cl-concentration. The semiconducting behavior of the passive film was investigated by Mott-Schottky analysis and the point defect model(PDM). It was observed that the iron cation vacancies and oxygen vacancies were continuously generated by autocatalytic reactions and the higher Cl^- concentration resulted in higher vacancies in the passive film. Once the excess vacancies condensed at the metal/film interface, the passive film became locally detached from the metal, which led to the breakdown of the passive film.展开更多
Intramedullary pressure increases after spinal cord injury, and this can be an important factor for secondary spinal cord injury. Until now there have been no studies of the dynamic changes of intramedullary pressure ...Intramedullary pressure increases after spinal cord injury, and this can be an important factor for secondary spinal cord injury. Until now there have been no studies of the dynamic changes of intramedullary pressure after spinal cord injury. In this study, telemetry systems were used to observe changes in intramedullary pressure in the 72 hours following spinal cord injury to explore its pathological mechanisms. Spinal cord injury was induced using an aneurysm clip at T10 of the spinal cord of 30 Japanese white rabbits, while another 32 animals were only subjected to laminectomy. The feasibility of this measurement was assessed. Intramedullary pressure was monitored in anesthetized and conscious animals. The dynamic changes of intramedullary pressure after spinal cord injury were divided into three stages: stage I(steep rise) 1–7 hours, stage Ⅱ(steady rise) 8–38 hours, and stage Ⅲ(descending) 39–72 hours. Blood-spinal barrier permeability, edema, hemorrhage, and histological results in the 72 hours following spinal cord injury were evaluated according to intramedullary pressure changes. We found that spinal cord hemorrhage was most severe at 1 hour post-spinal cord injury and then gradually decreased; albumin and aquaporin 4 immunoreactivities first increased and then decreased, peaking at 38 hours. These results confirm that severe bleeding in spinal cord tissue is the main cause of the sharp increase in intramedullary pressure in early spinal cord injury. Spinal cord edema and blood-spinal barrier destruction are important factors influencing intramedullary pressure in stages Ⅱ and Ⅲ of spinal cord injury.展开更多
Based on the Wallerian degeneration in the spinal cord pathways,the changes in synaptic connections,and the spinal cord-related cellular responses that alter the cellular structure of the brain,we presumed that brain ...Based on the Wallerian degeneration in the spinal cord pathways,the changes in synaptic connections,and the spinal cord-related cellular responses that alter the cellular structure of the brain,we presumed that brain diffusion tensor imaging(DTI)parameters may change after spinal cord injury.However,the dynamic changes in DTI parameters remain unclear.We established a Beagle dog model of T10 spinal cord contusion and performed DTI of the injured spinal cord.We found dynamic changes in DTI parameters in the cerebral peduncle,posterior limb of the internal capsule,pre-and postcentral gyri of the brain within 12 weeks after spinal cord injury.We then performed immunohistochemistry to detect the expression of neurofilament heavy polypeptide(axonal marker),glial fibrillary acidic protein(glial cell marker),and NeuN(neuronal marker).We found that these pathological changes were consistent with DTI parameter changes.These findings suggest that DTI can display brain structure changes after spinal cord injury.展开更多
AIM: To search candidate tumor suppressor genes (TSGs) on chromosome 4q through detecting high loss of heterozygosity (LOH) regions in sporadic colorectal carcinoma in Chinese patients. METHODS: Thirteen fluorescent l...AIM: To search candidate tumor suppressor genes (TSGs) on chromosome 4q through detecting high loss of heterozygosity (LOH) regions in sporadic colorectal carcinoma in Chinese patients. METHODS: Thirteen fluorescent labeled polymorphic microsatellite markers were analyzed in 83 cases of colorectal carcinoma and matched normal tissue DNA by polymerase chain reaction (PCR). PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.7 and Genotype 3.7 software were used for LOH scanning and analysis. Comparison between LOH frequency and clinicopathological factors were performed by χ2 test. RESULTS: Data were collected on all informative loci. The average LOH frequency on 4q was 28.56%. The D4S2915 locus showed highest LOH frequency (36.17%). Two obvious deletion regions were detected: one between D4S3000 and D4S2915 locus (4q12-21.1), another flanked by D4S407 and D4S2939 locus (4q25-31.1). None case showed complete deletion of 4q, most cases displayed interstitial deletion pattern solely. Furthermore, compared with clinicopathological features, a significant relationship was observed between LOH frequencies on D4S3018locus. In tumors larger than 5 cm in diameter, LOH frequency was significantly higher than tumors that were less than 5 cm (56% vs 13.79%, P = 0.01). On D4S1534 locus, LOH was significantly associated with liver metastasis (80% vs 17.25%, P = 0.012). No relationship was detected on other locus compared with clinicopathologial features. CONCLUSION: By high resolution deletion mapping, two high frequency regions of LOH (4q12-21.1 and 4q25-31.1) were detected, which may contribute to locate TSGs on chromosome 4q involved in carcinogenesis and progression of sporadic colorectal carcinoma.展开更多
AIM: To study the candidate tumor suppressor genes (TSG) on chromosome 4p by detecting the high frequency of loss of heterozygosity (LOH) in sporadic colorectal carcinoma in Chinese patients.METHODS: Seven fluorescent...AIM: To study the candidate tumor suppressor genes (TSG) on chromosome 4p by detecting the high frequency of loss of heterozygosity (LOH) in sporadic colorectal carcinoma in Chinese patients.METHODS: Seven fluorescent labeled polymorphic microsatellite markers were analyzed in 83 cases of colorectal carcinoma and matched normal tissue DNA by PCR. PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.7 and Genotype 3.7 software were used for LOH scanning and analysis. The same procedure was performed by the other six microsatellite markers spanning D4S3013 locus to make further detailed deletion mapping. Comparison between LOH frequency and clinicopathological factors was performed by χ2 test.RESULTS: Data were collected from all informative loci. The average LOH frequency on 4p was 24.25%, and 42.3% and 35.62% on D4S405 and D4S3013 locus, respectively. Adjacent markers of D4S3013 displayed a low LOH frequency (< 30%) by detailed deletion mapping. Significant opposite difference was observed between LOH frequency and tumor diameter on D4S412 and D4S1546 locus (0% vs 16.67%, P = 0.041; 54.55% vs 11.11%, P = 0.034, respectively). On D4S403 locus, LOH was significantly associated with tumor gross pattern (11.11%, 0, 33.33%, P = 0.030). No relationship was detected on other loci compared with clinicopathologial features.CONCLUSION: By deletion mapping, two obvious high frequency LOH regions spanning D4S3013 (4p15.2) and D4S405 (4p14) locus are detected. Candidate TSG, which is involved in carcinogenesis and progression of sporadic colorectal carcinoma on chromosome 4p, may be located between D4S3017 and D4S2933 (about 1.7 cm).展开更多
BACKGROUND Myeloid sarcoma(MS) is relatively rare,occurring mainly in the skin and lymph nodes,and MS invasion of the ulnar nerve is particularly unusual.The main aim of this article is to present a case of MS invadin...BACKGROUND Myeloid sarcoma(MS) is relatively rare,occurring mainly in the skin and lymph nodes,and MS invasion of the ulnar nerve is particularly unusual.The main aim of this article is to present a case of MS invading the brachial plexus,causing ulnar nerve entrapment syndrome,and to further clinical understanding of the possibility of MS invasion of peripheral nerves.CASE SUMMARY We present the case of a 46-year-old man with a 13-year history of well-treated acute nonlymphocytic leukaemia who was admitted to the hospital after presenting with numbness and pain in his left little finger.The initial diagnosis was considered a simple case of nerve entrapment disease,with magnetic resonance imaging showing slightly abnormal left brachial plexus nerve alignment with local thickening,entrapment,and high signal on compression lipid images.Due to the severity of the ulnar nerve compression,we surgically investigated and cleared the entrapment and nerve tissue hyperplasia;however,subsequent pathological biopsy results revealed evidence of MS.The patient had significant relief from his neurological symptoms,with no postoperative complications,and was referred to the haemato-oncology department for further consultation about the primary disease.This is the first report of safe treatment of ulnar nerve entrapment from MS.It is intended to inform hand surgeons that nerve entrapment may be associated with extramedullary MS,as a rare presenting feature of the disease.CONCLUSION MS invasion of the brachial plexus and surrounding tissues of the upper arm,resulting in ulnar nerve entrapment and degeneration with significant neurological pain and numbness in the little finger,is uncommon.Surgical treatment significantly relieved the patient’s nerve entrapment symptoms and prevented further neurological impairment.This case is reported to highlight the rare presenting features of MS.展开更多
Objective:To explore the clinical efficacy of perinodopril in the treatment of heart failure in patients after myocardial infarction and effect on the myocardial energy consumption. Methods:A total of 87 patients with...Objective:To explore the clinical efficacy of perinodopril in the treatment of heart failure in patients after myocardial infarction and effect on the myocardial energy consumption. Methods:A total of 87 patients with heart failure after myocardial infarction who were admitted in our hospital from August, 2014 to October, 2015 were included in the study and divided into the routine dose group (n=43, perinodopril 4 mg/d) and high dose group (n=44, perinodopril 8 mg/d) according to the long-term oral dose. All the patients were given perinodopril, continuously for 6 months. The changes of blood pressure and serum biochemical indicators before and after treatment in the two groups were compared. The changes of cardiac function indicators and myocardial energy consumption indicators before and after treatment in the two groups were compared. 6MWT 6 months and 1 year after treatment in the two groups was calculated.Results: The plasma BNP and H-FABP levels, LVEDD, LVESD, MEE, and cESS after treatment in the two groups were significantly reduced when compared with before treatment, and those in the high dose group were significantly lower than those in the low dose group. LVEF and FS after treatment in the two groups were significantly increased, and those in the high dose group were significantly greater than those in the routine dose group. The seurm potassium level after treatment in the high dose group was significantly elevated when compared with before treatment, but was not significantly different from that in the routine dose group. SBP, DBP, and Scr levels after treatment in the two groups were not significantly changed. 6MWT 6 months and 1 year after treatment in the high dose group was significantly greater than that in the routine dose group.Conclusions: Perinodopril in a high dose can significantly reduce the plasma BNP and H-FABP levels in patients with heart failure after myocardial infarction, inhibit the ventricular remodeling, promote the recovery of systolic function, reduce the myocardial energy consumption, and will not affect the blood pressure, serum potassium, and renal function, with efficacy significantly superior to that in a low dose;moreover, it has a certain safety.展开更多
Solidification behavior in the mold region plays an important role in production efficiency and steel quality.To investigate shell growth within a mold,the sulfur prints of the entire shell thickness profile the menis...Solidification behavior in the mold region plays an important role in production efficiency and steel quality.To investigate shell growth within a mold,the sulfur prints of the entire shell thickness profile the meniscus to 100 mm below the mold were obtainedadding FeS tracer into molten steel during bloom continuous casting of hypo-peritectic steel.The law of shell thickness evolution along mold height and circumference was analyzed.The results show that there are three weak regions of solidification,which are in the mold upper part,in the mold lower part,and just below mold exit,possibly resulting periodic fluctuation of air gap between the shell and the mold,the impingement of melt jets on the solidification front,and the decreasing cooling intensity,respectively.Initial solidification point along casting direction appears at approximately 35 mm below the meniscus.Overall,the solidified shell thickness in the inner side of the mold is a little larger than that in the outer side,and the former and the latter reach 25.5 and 24.3 mm at the mold exit,respectively.The non-uniform shell growth in the inner side of the bloom is provided,while shell thicknesses in the narrow face and the outer side follow relatively regular growth.Out of the mold,the thinnest shells on the transverse section exist in the regions of 60–90 mm and 40–70 mm the corners of the inner and outer sides,respectively,i.e.,the of-corners.展开更多
Purpose:Child head injury under impact scenarios(e.g.falls,vehicle crashes,etc.)is an important topic in the field of injury biomechanics.The head of piglet was commonly used as the surrogate to investigate the biomec...Purpose:Child head injury under impact scenarios(e.g.falls,vehicle crashes,etc.)is an important topic in the field of injury biomechanics.The head of piglet was commonly used as the surrogate to investigate the biomechanical response and mechanisms of pediatric head injuries because of the similar cellular structures and material properties.However,up to date,piglet head models with accurate geometry and material properties,which have been validated by impact experiments,are seldom.We aim to develop such a model for future research.Methods:In this study,first,the detailed anatomical structures of the piglet head,including the skull,suture,brain,pia mater,dura mater,cerebrospinal fluid,scalp and soft tissue,were constructed based on CT scans.Then,a structured butterfly method was adopted to mesh the complex geometries of the piglet head to generate high-quality elements and each component was assigned corresponding constitutive material models.Finally,the guided drop tower tests were conducted and the force-time histories were ectracted to validate the piglet head finite element model.Results:Simulations were conducted on the developed finite element model under impact conditions and the simulation results were compared with the experimental data from the guided drop tower tests and the published literature.The average peak force and duration of the guide drop tower test were similar to that of the simulation,with an error below 10%.The inaccuracy was below 20%.The average peak force and duration reported in the literature were comparable to those of the simulation,with the exception of the duration for an impact energy of 11 J.The results showed that the model was capable to capture the response of the pig head.Conclusion:This study can provide an effective tool for investigating child head injury mechanisms and protection strategies under impact loading conditions.展开更多
Based on the two-step nucleation mechanism, a multi-step thermodynamic model for alumina inclusion for- mation during aluminum deoxidation process was proposed in Fe-O-Al melt. Thermodynamic properties of metastable i...Based on the two-step nucleation mechanism, a multi-step thermodynamic model for alumina inclusion for- mation during aluminum deoxidation process was proposed in Fe-O-Al melt. Thermodynamic properties of metastable intermediates including (Al2O3)n clusters for prenucleation and α-Al2O3 nanoparticle for growth process were calculated using density functional theory. Furthermore, Gibbs free energy change of forming the intermediate by reaction between the dissolved aluminum (Al) and oxygen (O) in the melt was calculated. The results indicated that the thermodynamics of (Al2O3)n at steelmaking temperature are dependent on their structures, while that of α-Al2O3 nanoparticle are dependent on their size. The nuclei of α-Al2O3 which was originated from (Al2O3)n aggregated under a high supersaturation ratio of Al and O(Rs) in the melt. There existing excess oxygen because of the low Rs, but the secondary inclusions will be formed during the cooling process due to the excess oxygen. The nuclei lager than 20 nm can grow up spontaneously and instantaneously into primary inclusions because of thermodynamic drive. It is difficult to control the size of α-Al2O3 to be less than 20 nm, in the aluminum deoxidation process of the current conditions of steelmaking.展开更多
With the popularity of urine flow dynamic monitoring and indwelling catheter technologies in animal experiments,the urethral catheterization has become a common technique in scientific research.The miniature pig is co...With the popularity of urine flow dynamic monitoring and indwelling catheter technologies in animal experiments,the urethral catheterization has become a common technique in scientific research.The miniature pig is considered as one of the major animal species used in scientific research and is increasingly being used as an alternative to a dog or monkey as the nonrodent species of choice in the preclinical toxicological testing of pharmaceuticals.[1] Since there are three acute angles bending in the urethra of the male miniature pig,and the end of the penis head is cork-screw shaped,it is difficult to implement routine urethral catheterization in male miniature pigs.Currently,researchers usually implement bladder colostomies or dissections in male miniature pigs,while transurethral urethral catheterization can be implemented in female miniature pigs.According to the existing reports,implementing transurethral urethral catheterization in female miniature pigs is seldom seen.[2] We chose 3-month-old female Bama miniature pigs in our experiments and employ the following methods:first,use a "V"-shaped platform with an angle of about 30° to the horizontal plane;second,utilize a pediatric laryngoscope for deep lighting;third,bend the lower limbs and press down to the ventral side.Satisfactory results through transurethral urethral catheterization were achieved in the end.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51171022)
文摘The effect of H2S concentration on H2S/CO2 corrosion of API-X60 steel was studied by scanning electron microscopy, a weight-loss method, potentiodynamic polarization tests, and the electrochemical impedance spectroscopy technique. It is found that the cor-rosion process of the steel in an environment where H2S and CO2 coexist at different H2S concentrations is related to the morphological structure and stability of the corrosion product film. With the addition of a small amount of H2S, the size of the anode reaction region is de-creased due to constant adsorption and separation of more FeS sediment or more FeHS+ions on the surface of the steel. Meanwhile, the dou-ble-layer capacitance is diminished with increasing anion adsorption capacity. Therefore, the corrosion process is inhibited. The general cor-rosion rate of the steel rapidly decreases after the addition of a small amount of H2S under the coexistence of H2S and CO2. With a further increase in H2S concentration, certain parts of the corrosion product film become loose and even fall off. Thus, the protection provided by the corrosion product film worsens, and the corrosion rate tends to increase.
基金by the National Natural Science Foundation of China(41772076,41672084,41372086,41503038)the National Key Research and Development Program of China(2016YFC0600105-04,2016YFC0600606)+1 种基金the Key Research and Development Program of Shandong Province(2017CXGC1601,2017CXGC1602,2017CXGC1603),the Special Fund for“Taishan Scholars”Project of Shandong Province.
文摘Recently,continuous breakthroughs have been made about deep gold prospecting in the Jiaodong gold province area of China.Approximately 5000 t of cumulative gold resources have been explored in Jiaodong,which has thus become an internationally noteworthy gold ore cluster.The gold exploration depth has been increased to about 2000 m from the previous<1000 m.To further explore the mineralization potential of the Jiaodong area at a depth of about 3000 m,the Shandong Institute of Geological Sciences has drilled an exploratory drillhole named“Deep drillhole ZK01”to a depth of 3266 m.Hence,as reported herein,the mineralization characteristics of the Jiaojia metallogenic belt have been successfully documented.ZK01 is,to date,the deepest borehole with an gold intersect in China,and constitutes a significant advance in deep gold prospecting in China.The findings of this study further indicate that the depth interval of 2000 m to 4000 m below the ground surface in the Wuyi Village area incorporates 912 t of inferred gold resources,while the depth interval of 2000 m to 4000 m below the surface across the Jiaodong area possesses about 4000 t of inferred gold resources.The Jiaojia Fault Belt tends to gently dip downward,having dip angles of about 25°and about 20°at vertical depths of 2000 m and 2850 m,respectively.The deep part of the Jiaojia metallogenic belt differs from the shallow and moderately deep parts about fracturing,alteration,mineralization,and tectonic type.The deep zones can generally be categorized from inside outward as cataclastic granite,granitic cataclasite,weakly beresitized granitic cataclasite,beresitized cataclasite,and gouge.These zones exhibit a gradual transitional relation or occur alternately and repeatedly.The mineralization degree of the pyritized cataclastic granite-type ore in the deep part of the Jiaojia metallogenic belt is closely related to the degree of pyrite vein development;that is,the higher the pyrite content,the wider the veins and the higher the gold grade.Compared to the shallow gold ores,the deep-seated gold ores have higher fineness and contain joseite,tetradymite,and native bismuth,suggesting that the deep gold mineralization temperature is higher and that mantle-sourced material may have contributed to this mineralization.ZK01 has also revealed that the deep-seated ore bodies in the Jiaojia metallogenic belt are principally situated above the main fracture plane(gouge)and hosted within the Linglong Granite,contradicting previous findings indicating that the moderately shallow gold ore bodies are usually hosted in the contact zone between the Linglong Granite and Jiaodong Group or meta-gabbro.These new discoveries are particularly significant because they can help correct mineralization prospecting models,determine favorable positions for deep prospecting,and improve metallogenic prediction and resource potential evaluation.
文摘BACKGROUND Epithelioid trophoblastic tumor(ETT) is the rarest type of gestational trophoblastic tumor(GTT). It has been reported that more than 50% of ETTs arise in the uterine cervix or the lower uterine segment. Here, we report a case of ETT within the lower uterine segment and cervical canal and discuss its manifestations,possible causes, and related influencing factors.CASE SUMMARY A 35-year-old woman(gravida 7, miscarriage 3, induction 2 with 1 being twins,para 2 of cesarean section, live 2), who had amenorrhea for 9 mo after breastfeeding for 22 mo after the last cesarean section, was diagnosed with ETT. The lesion was present in the lower uterine segment and endocervical canal with severe involvement of the anterior wall of the lower uterine segment and the front wall of the lower uterine segment where the cesarean incisions were made.Laboratory tests showed slight elevation of serum beta-human chorionic gonadotropin. Intraoperative exploration showed the presence of a normal-sized uterus body with an enlarged tumor in the lower uterine segment. The surface of the lower uterine segment was light blue, the entire lesion was approximately about 8cm × 8 cm × 9 cm, with compression and displacement of the surrounding tissue.Histological examination diagnosed ETT. Immunohistochemical analysis showed positive expression of p63, with a Ki-67 proliferation index of 40%.CONCLUSION A search of the PubMed database using the search terms "cesarean section" and "epithelioid trophoblastic tumor" retrieved nine articles, including 13 cases of ETT and ETT-related lesions, all 13 cases had a history of cesarean section, and the lesions were all located at the cesarean section incision on the anterior wall of the lower uterine segment. The present case is the 14th reported case of ETT after cesarean section. Therefore, we deduced that cesarean section trauma had an important effect on the occurrence of ETT at this site.
文摘BACKGROUND Hourglass-like constriction neuropathy is a rare neurological disorder.The main clinical manifestation is peripheral nerve injury with no apparent cause,and the pathomorphological change is an unexplained narrowing of the diseased nerve.The diagnosis and treatment of the disease are challenging and there is no accepted diagnostic or therapeutic approach.CASE SUMMARY This report describes a rare hourglass constriction of the anterior interosseous nerve in the left forearm in a 47-year-old healthy male who was treated surgically and gradually recovered function over a 6-mo follow-up period.CONCLUSION Hourglass-like constriction neuropathy is a rare disorder.With the development of medical technology,more examinations are now available for diagnosis.This case aims to highlight the rare manifestations of Hourglass-like constriction neuropathy and provides a reference for enriching the clinical diagnosis and treatment experience.
文摘Objective:To explore the effect of partial body weight support training (PBWST) on the cardiac function, neuroendocrine function, and vascular endothelial function in patients with early heart failure.Methods: A total of 98 patients with early heart failure who were admitted in our hospital were included in the study and randomized into the observation group and the control group. The patients in the control group were given routine drugs and rehabilitation. On this basis, the patients in the observation group were given PBWST. The patients in the two groups were treated for 3 months. The changes of cardiac function, neuroendocrine function, and vascular endothelial function indicators before and after rehabilitation in the two groups were detected.Results: LVESD and ESV after training in the two groups were significantly reduced. LVESD and ESV after training in the observation group were significantly lower than those in the control group. SV, CI, LVEF, and FS after training in the observation group were significantly elevated when compared with before training. LVEF and FS after training in the observation group were significantly higher than those in the control group. LVEF after training in the control group was significantly elevated. PRA, AngⅡ, ET, and ALD levels after training in the observation group were significantly reduced, while NO was significantly elevated, and the improvement of the above indicators was significantly superior to that in the control group.Conclusions: PBWST can improve the cardiac function in patients with early heart failure, inhibit the excessive activation of neuroendocrine system, and protect the vascular endothelial function in order to enhance the clinical efficacy.
基金supported by the National Natural Science Foundation of China,No.81272164the Special Fund for Basic Scientific Research of Central Public Research Institutes in China,No.2015CZ-6,2016CZ-4+2 种基金the Beijing Institute for Brain Disorders in China,No.201601,0000-100031the Supporting Program of the “Twelve Five-year Plan” for Science&Technology Research of China,No.2012BAI34B02a grant from the Ministry of Science and Technology of China,No.2015CB351701
文摘Exploring the relationship between different structure of the spinal cord and functional assessment after spinal cord injury is important. Quantitative diffusion tensor imaging can provide information about the microstructure of nerve tissue and can quantify the pathological damage of spinal cord white matter and gray matter. In this study, a custom-designed spinal cord contusion-impactor was used to damage the T_(10) spinal cord of beagles. Diffusion tensor imaging was used to observe changes in the whole spinal cord, white matter, and gray matter, and the Texas Spinal Cord Injury Score was used to assess changes in neurological function at 3 hours, 24 hours, 6 weeks, and 12 weeks after injury. With time, fractional anisotropy values after spinal cord injury showed a downward trend, and the apparent diffusion coefficient, mean diffusivity, and radial diffusivity first decreased and then increased. The apparent diffusion-coefficient value was highly associated with the Texas Spinal Cord Injury Score for the whole spinal cord(R = 0.919, P = 0.027), white matter(R = 0.932, P = 0.021), and gray matter(R = 0.882, P = 0.048). Additionally, the other parameters had almost no correlation with the score(P 〉 0.05). In conclusion, the highest and most significant correlation between diffusion parameters and neurological function was the apparent diffusion-coefficient value for white matter, indicating that it could be used to predict the recovery of neurological function accurately after spinal cord injury.
基金Supported by National Science Foundation(81502322)
文摘Objective:To investigate the expression of targeting protein for Xenopus kinesin-like protein 2(TPX2) in breast cancer tissue and to explore its role in proliferation,migration and invasion of breast cancer cells.Methods:The mRNA and protein expressions of TPX2 in breast cancer tissue and cell lines were assessed by quantitative RT-PCR and Western blot.The effect of TPX2 with RNA interference on proliferation,invasion and migration of breast cancer cells was observed by MTT and Transwell assays.Results:Both mRNA and protein expressions of TPX2 were upregulated in breast cancer tissues compared to tumor-adjacent tissue.TPX2 expression was also upregulated in breast cancer cell lines,and the TPX2 interfered by small interfering RNA could inhibit the proliferation,invasion and migration of breast cancer cells by inhibiting matrix metalloproteinase-2 and matrix metalloproteinase-9.Conclusions:Significantly upregulated TPX2 expression is observed in breast cancer tissue and cells,and contributes to promote the proliferation,migration and invasion of breast cancer cells.
基金financially supported by the National Science and Technology Major Project of China (No. 2016ZX05028-004)
文摘Herein, the effect of high chloride ion(Cl^-) concentration on the corrosion behavior and passive film breakdown of 13Cr martensitic stainless steel under CO_2 environment was demonstrated. The Cl^- concentration was varied from 30 to 150 g/L and cyclic potentiodynamic polarization was conducted to investigate the influence of the Cl^- concentration on the corrosion potential(E_(corr)), passive breakdown potential(E_(pit)), and repassivation potential(E_(rep)). The results of the polarization curves revealed that 13Cr stainless steel is susceptible to pitting under high Cl^- concentration. The passive breakdown potential and repassivation potential decreased with the increase of Cl-concentration. The semiconducting behavior of the passive film was investigated by Mott-Schottky analysis and the point defect model(PDM). It was observed that the iron cation vacancies and oxygen vacancies were continuously generated by autocatalytic reactions and the higher Cl^- concentration resulted in higher vacancies in the passive film. Once the excess vacancies condensed at the metal/film interface, the passive film became locally detached from the metal, which led to the breakdown of the passive film.
基金supported by the National Natural Science Foundation of China,No.81272164(to JJL)the Special Fund for Basic Scientific Research of Central Public Research Institutes in China,No.2016CZ-4(to JJL),2018CZ-1(to JJL)+1 种基金the Beijing Institute for Brain Disorders in China,No.0000-100031(to JJL)the Basic Scientific Research Foundation of China Rehabilitation Research Center,No.2017ZX-22,2017ZX-20(to JJL)
文摘Intramedullary pressure increases after spinal cord injury, and this can be an important factor for secondary spinal cord injury. Until now there have been no studies of the dynamic changes of intramedullary pressure after spinal cord injury. In this study, telemetry systems were used to observe changes in intramedullary pressure in the 72 hours following spinal cord injury to explore its pathological mechanisms. Spinal cord injury was induced using an aneurysm clip at T10 of the spinal cord of 30 Japanese white rabbits, while another 32 animals were only subjected to laminectomy. The feasibility of this measurement was assessed. Intramedullary pressure was monitored in anesthetized and conscious animals. The dynamic changes of intramedullary pressure after spinal cord injury were divided into three stages: stage I(steep rise) 1–7 hours, stage Ⅱ(steady rise) 8–38 hours, and stage Ⅲ(descending) 39–72 hours. Blood-spinal barrier permeability, edema, hemorrhage, and histological results in the 72 hours following spinal cord injury were evaluated according to intramedullary pressure changes. We found that spinal cord hemorrhage was most severe at 1 hour post-spinal cord injury and then gradually decreased; albumin and aquaporin 4 immunoreactivities first increased and then decreased, peaking at 38 hours. These results confirm that severe bleeding in spinal cord tissue is the main cause of the sharp increase in intramedullary pressure in early spinal cord injury. Spinal cord edema and blood-spinal barrier destruction are important factors influencing intramedullary pressure in stages Ⅱ and Ⅲ of spinal cord injury.
基金supported by the National Natural Science Foundation of China, No. 82102676 (to CBL)a grant from Beijing Municipal Science & Technology Commission, No. Z171100001017076 (to JJL)+1 种基金National Key Research and Development Program, No. 2018YFF0301104 (to JJL)Research on Medical Protection Technology and Application of Induced Neural Stem Cells in the Treatment of Military Spinal Cord Injury, No. Z181100004118004 (to JL)
文摘Based on the Wallerian degeneration in the spinal cord pathways,the changes in synaptic connections,and the spinal cord-related cellular responses that alter the cellular structure of the brain,we presumed that brain diffusion tensor imaging(DTI)parameters may change after spinal cord injury.However,the dynamic changes in DTI parameters remain unclear.We established a Beagle dog model of T10 spinal cord contusion and performed DTI of the injured spinal cord.We found dynamic changes in DTI parameters in the cerebral peduncle,posterior limb of the internal capsule,pre-and postcentral gyri of the brain within 12 weeks after spinal cord injury.We then performed immunohistochemistry to detect the expression of neurofilament heavy polypeptide(axonal marker),glial fibrillary acidic protein(glial cell marker),and NeuN(neuronal marker).We found that these pathological changes were consistent with DTI parameter changes.These findings suggest that DTI can display brain structure changes after spinal cord injury.
基金The National Natural Science Foundation of China, No. 30080016 and No. 30470977
文摘AIM: To search candidate tumor suppressor genes (TSGs) on chromosome 4q through detecting high loss of heterozygosity (LOH) regions in sporadic colorectal carcinoma in Chinese patients. METHODS: Thirteen fluorescent labeled polymorphic microsatellite markers were analyzed in 83 cases of colorectal carcinoma and matched normal tissue DNA by polymerase chain reaction (PCR). PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.7 and Genotype 3.7 software were used for LOH scanning and analysis. Comparison between LOH frequency and clinicopathological factors were performed by χ2 test. RESULTS: Data were collected on all informative loci. The average LOH frequency on 4q was 28.56%. The D4S2915 locus showed highest LOH frequency (36.17%). Two obvious deletion regions were detected: one between D4S3000 and D4S2915 locus (4q12-21.1), another flanked by D4S407 and D4S2939 locus (4q25-31.1). None case showed complete deletion of 4q, most cases displayed interstitial deletion pattern solely. Furthermore, compared with clinicopathological features, a significant relationship was observed between LOH frequencies on D4S3018locus. In tumors larger than 5 cm in diameter, LOH frequency was significantly higher than tumors that were less than 5 cm (56% vs 13.79%, P = 0.01). On D4S1534 locus, LOH was significantly associated with liver metastasis (80% vs 17.25%, P = 0.012). No relationship was detected on other locus compared with clinicopathologial features. CONCLUSION: By high resolution deletion mapping, two high frequency regions of LOH (4q12-21.1 and 4q25-31.1) were detected, which may contribute to locate TSGs on chromosome 4q involved in carcinogenesis and progression of sporadic colorectal carcinoma.
基金Supported by The National Natural Science Foundation of China, No. 30080016 and No. 30470977
文摘AIM: To study the candidate tumor suppressor genes (TSG) on chromosome 4p by detecting the high frequency of loss of heterozygosity (LOH) in sporadic colorectal carcinoma in Chinese patients.METHODS: Seven fluorescent labeled polymorphic microsatellite markers were analyzed in 83 cases of colorectal carcinoma and matched normal tissue DNA by PCR. PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.7 and Genotype 3.7 software were used for LOH scanning and analysis. The same procedure was performed by the other six microsatellite markers spanning D4S3013 locus to make further detailed deletion mapping. Comparison between LOH frequency and clinicopathological factors was performed by χ2 test.RESULTS: Data were collected from all informative loci. The average LOH frequency on 4p was 24.25%, and 42.3% and 35.62% on D4S405 and D4S3013 locus, respectively. Adjacent markers of D4S3013 displayed a low LOH frequency (< 30%) by detailed deletion mapping. Significant opposite difference was observed between LOH frequency and tumor diameter on D4S412 and D4S1546 locus (0% vs 16.67%, P = 0.041; 54.55% vs 11.11%, P = 0.034, respectively). On D4S403 locus, LOH was significantly associated with tumor gross pattern (11.11%, 0, 33.33%, P = 0.030). No relationship was detected on other loci compared with clinicopathologial features.CONCLUSION: By deletion mapping, two obvious high frequency LOH regions spanning D4S3013 (4p15.2) and D4S405 (4p14) locus are detected. Candidate TSG, which is involved in carcinogenesis and progression of sporadic colorectal carcinoma on chromosome 4p, may be located between D4S3017 and D4S2933 (about 1.7 cm).
文摘BACKGROUND Myeloid sarcoma(MS) is relatively rare,occurring mainly in the skin and lymph nodes,and MS invasion of the ulnar nerve is particularly unusual.The main aim of this article is to present a case of MS invading the brachial plexus,causing ulnar nerve entrapment syndrome,and to further clinical understanding of the possibility of MS invasion of peripheral nerves.CASE SUMMARY We present the case of a 46-year-old man with a 13-year history of well-treated acute nonlymphocytic leukaemia who was admitted to the hospital after presenting with numbness and pain in his left little finger.The initial diagnosis was considered a simple case of nerve entrapment disease,with magnetic resonance imaging showing slightly abnormal left brachial plexus nerve alignment with local thickening,entrapment,and high signal on compression lipid images.Due to the severity of the ulnar nerve compression,we surgically investigated and cleared the entrapment and nerve tissue hyperplasia;however,subsequent pathological biopsy results revealed evidence of MS.The patient had significant relief from his neurological symptoms,with no postoperative complications,and was referred to the haemato-oncology department for further consultation about the primary disease.This is the first report of safe treatment of ulnar nerve entrapment from MS.It is intended to inform hand surgeons that nerve entrapment may be associated with extramedullary MS,as a rare presenting feature of the disease.CONCLUSION MS invasion of the brachial plexus and surrounding tissues of the upper arm,resulting in ulnar nerve entrapment and degeneration with significant neurological pain and numbness in the little finger,is uncommon.Surgical treatment significantly relieved the patient’s nerve entrapment symptoms and prevented further neurological impairment.This case is reported to highlight the rare presenting features of MS.
文摘Objective:To explore the clinical efficacy of perinodopril in the treatment of heart failure in patients after myocardial infarction and effect on the myocardial energy consumption. Methods:A total of 87 patients with heart failure after myocardial infarction who were admitted in our hospital from August, 2014 to October, 2015 were included in the study and divided into the routine dose group (n=43, perinodopril 4 mg/d) and high dose group (n=44, perinodopril 8 mg/d) according to the long-term oral dose. All the patients were given perinodopril, continuously for 6 months. The changes of blood pressure and serum biochemical indicators before and after treatment in the two groups were compared. The changes of cardiac function indicators and myocardial energy consumption indicators before and after treatment in the two groups were compared. 6MWT 6 months and 1 year after treatment in the two groups was calculated.Results: The plasma BNP and H-FABP levels, LVEDD, LVESD, MEE, and cESS after treatment in the two groups were significantly reduced when compared with before treatment, and those in the high dose group were significantly lower than those in the low dose group. LVEF and FS after treatment in the two groups were significantly increased, and those in the high dose group were significantly greater than those in the routine dose group. The seurm potassium level after treatment in the high dose group was significantly elevated when compared with before treatment, but was not significantly different from that in the routine dose group. SBP, DBP, and Scr levels after treatment in the two groups were not significantly changed. 6MWT 6 months and 1 year after treatment in the high dose group was significantly greater than that in the routine dose group.Conclusions: Perinodopril in a high dose can significantly reduce the plasma BNP and H-FABP levels in patients with heart failure after myocardial infarction, inhibit the ventricular remodeling, promote the recovery of systolic function, reduce the myocardial energy consumption, and will not affect the blood pressure, serum potassium, and renal function, with efficacy significantly superior to that in a low dose;moreover, it has a certain safety.
基金This work was supported by the National Natural Science Foundation of China(51604021).
文摘Solidification behavior in the mold region plays an important role in production efficiency and steel quality.To investigate shell growth within a mold,the sulfur prints of the entire shell thickness profile the meniscus to 100 mm below the mold were obtainedadding FeS tracer into molten steel during bloom continuous casting of hypo-peritectic steel.The law of shell thickness evolution along mold height and circumference was analyzed.The results show that there are three weak regions of solidification,which are in the mold upper part,in the mold lower part,and just below mold exit,possibly resulting periodic fluctuation of air gap between the shell and the mold,the impingement of melt jets on the solidification front,and the decreasing cooling intensity,respectively.Initial solidification point along casting direction appears at approximately 35 mm below the meniscus.Overall,the solidified shell thickness in the inner side of the mold is a little larger than that in the outer side,and the former and the latter reach 25.5 and 24.3 mm at the mold exit,respectively.The non-uniform shell growth in the inner side of the bloom is provided,while shell thicknesses in the narrow face and the outer side follow relatively regular growth.Out of the mold,the thinnest shells on the transverse section exist in the regions of 60–90 mm and 40–70 mm the corners of the inner and outer sides,respectively,i.e.,the of-corners.
基金National Natural Science Foundation of China(Grant No.51975041No.51505024)Funding of Ministry of Industry and Information Technology for Civil Aircraft(Grant No.MJ-2018-F-18)。
文摘Purpose:Child head injury under impact scenarios(e.g.falls,vehicle crashes,etc.)is an important topic in the field of injury biomechanics.The head of piglet was commonly used as the surrogate to investigate the biomechanical response and mechanisms of pediatric head injuries because of the similar cellular structures and material properties.However,up to date,piglet head models with accurate geometry and material properties,which have been validated by impact experiments,are seldom.We aim to develop such a model for future research.Methods:In this study,first,the detailed anatomical structures of the piglet head,including the skull,suture,brain,pia mater,dura mater,cerebrospinal fluid,scalp and soft tissue,were constructed based on CT scans.Then,a structured butterfly method was adopted to mesh the complex geometries of the piglet head to generate high-quality elements and each component was assigned corresponding constitutive material models.Finally,the guided drop tower tests were conducted and the force-time histories were ectracted to validate the piglet head finite element model.Results:Simulations were conducted on the developed finite element model under impact conditions and the simulation results were compared with the experimental data from the guided drop tower tests and the published literature.The average peak force and duration of the guide drop tower test were similar to that of the simulation,with an error below 10%.The inaccuracy was below 20%.The average peak force and duration reported in the literature were comparable to those of the simulation,with the exception of the duration for an impact energy of 11 J.The results showed that the model was capable to capture the response of the pig head.Conclusion:This study can provide an effective tool for investigating child head injury mechanisms and protection strategies under impact loading conditions.
基金financially supported by the National Natural Science Foundation of China (No. 51004054)Foundation from the Liaoning Province Education Department (No. L2013127)
文摘Based on the two-step nucleation mechanism, a multi-step thermodynamic model for alumina inclusion for- mation during aluminum deoxidation process was proposed in Fe-O-Al melt. Thermodynamic properties of metastable intermediates including (Al2O3)n clusters for prenucleation and α-Al2O3 nanoparticle for growth process were calculated using density functional theory. Furthermore, Gibbs free energy change of forming the intermediate by reaction between the dissolved aluminum (Al) and oxygen (O) in the melt was calculated. The results indicated that the thermodynamics of (Al2O3)n at steelmaking temperature are dependent on their structures, while that of α-Al2O3 nanoparticle are dependent on their size. The nuclei of α-Al2O3 which was originated from (Al2O3)n aggregated under a high supersaturation ratio of Al and O(Rs) in the melt. There existing excess oxygen because of the low Rs, but the secondary inclusions will be formed during the cooling process due to the excess oxygen. The nuclei lager than 20 nm can grow up spontaneously and instantaneously into primary inclusions because of thermodynamic drive. It is difficult to control the size of α-Al2O3 to be less than 20 nm, in the aluminum deoxidation process of the current conditions of steelmaking.
基金This study was supported by a grant from the National Natural Science Foundation of China (No. 81271366).
文摘With the popularity of urine flow dynamic monitoring and indwelling catheter technologies in animal experiments,the urethral catheterization has become a common technique in scientific research.The miniature pig is considered as one of the major animal species used in scientific research and is increasingly being used as an alternative to a dog or monkey as the nonrodent species of choice in the preclinical toxicological testing of pharmaceuticals.[1] Since there are three acute angles bending in the urethra of the male miniature pig,and the end of the penis head is cork-screw shaped,it is difficult to implement routine urethral catheterization in male miniature pigs.Currently,researchers usually implement bladder colostomies or dissections in male miniature pigs,while transurethral urethral catheterization can be implemented in female miniature pigs.According to the existing reports,implementing transurethral urethral catheterization in female miniature pigs is seldom seen.[2] We chose 3-month-old female Bama miniature pigs in our experiments and employ the following methods:first,use a "V"-shaped platform with an angle of about 30° to the horizontal plane;second,utilize a pediatric laryngoscope for deep lighting;third,bend the lower limbs and press down to the ventral side.Satisfactory results through transurethral urethral catheterization were achieved in the end.