Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,for...Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,forest land and fallow land were investigated in six regions of northern China.Generic richness,diversity,abundance and biomass of soil nematodes was the lowest in crop land.The richness and diversity of soil nematodes were 28.8and 15.1%higher in fallow land than in crop land,respectively.No significant differences in soil nematode indices were found between forest land and fallow land,but their network keystone genera composition was different.Among the keystone genera,50%of forest land genera were omnivores-predators and 36%of fallow land genera were bacterivores.The proportion of fungivores in forest land was 20.8%lower than in fallow land.The network complexity and the stability were lower in crop land than forest land and fallow land.Soil pH,NH_(4)^(+)-N and NO_(3)^(–)-N were the major factors influencing the soil nematode community in crop land while soil organic carbon and moisture were the major factors in forest land.Soil nematode communities in crop land influenced by artificial management practices were more dependent on the soil environment than communities in forest land and fallow land.Land use induced soil environment variation and altered network relationships by influencing trophic group proportions among keystone nematode genera.展开更多
Despite major achievements in the treatment ofchronic hepatitis C with the combination ofinterferons and the nucleoside analog ribavirin themajority of patients with chronic hepatitis C virus(HCV) infection cannot be ...Despite major achievements in the treatment ofchronic hepatitis C with the combination ofinterferons and the nucleoside analog ribavirin themajority of patients with chronic hepatitis C virus(HCV) infection cannot be treated effectively.Toimprove this response rate we used antisensetechnologies to inhibit HCV translation as possibleadditional option for experimental treatment.Antisense oligodeoxynucleotides(ODN) are展开更多
The plant Aloe vera is used in Ayurvedic, Homoeopathic and Allopathic streams of medicine, and not only tribal community but also most of the people for food and medicine. The plant leaves contains numerous vitamins, ...The plant Aloe vera is used in Ayurvedic, Homoeopathic and Allopathic streams of medicine, and not only tribal community but also most of the people for food and medicine. The plant leaves contains numerous vitamins, minerals, enzymes, amino acids, natural sugars and other bioactive compounds with emollient, purgative, anti-microbial, anti inflammatory, antioxidant, aphrodisiac, anti-helmenthic, antifungal, antiseptic and cosmetic values for health care. This plant has potential to cure sunburns, burns and minor cuts, and even skin cancer. The external use in cosmetic primarily acts as skin healer and prevents injury of epithelial tissues, cures acne and gives a youthful glow to skin, also acts as extremely powerful laxative.展开更多
BACKGROUND Blastocystis hominis(B.hominis),an anaerobic unicellular protist parasite,is known for its diverse clinical manifestations upon infecting the human gastrointestinal tract.Although globally distributed,it is...BACKGROUND Blastocystis hominis(B.hominis),an anaerobic unicellular protist parasite,is known for its diverse clinical manifestations upon infecting the human gastrointestinal tract.Although globally distributed,it is particularly prevalent in developing nations.Examining the symptoms and treatment outcomes of B.hominis infection in low-resource settings holds immense significance,providing healthcare practi-tioners with valuable insights to enhance patient care.AIM To synthesize existing evidence on the symptomatology and treatment outcomes of B.hominis infection in low-resource settings.METHODS Following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines,a systematic review was conducted.The search spanned electronic databases including PubMed,Scopus,and Google Scholar.After a comprehensive screening process,a thorough examination of the papers,adhering to inclusion and exclusion criteria,and data extraction from eligible studies was conducted.The findings underwent summarization through simple descriptive analysis.RESULTS The search yielded 1200 papers,with 17 meeting inclusion criteria.Chronic diarrhea due to B.hominis infection was reported in only two studies,while abdominal pain,diarrhea,flatulence,constipation,and nausea/vomiting emerged as the most commonly documented symptoms.Recovery rates after one week of treatment ranged from 71.8%to 100%,and after two weeks,from 60%to 100%.CONCLUSION In low-resource settings,chronic diarrhea resulting from B.hominis infection is infrequent.Common symptoms include abdominal pain,diarrhea,flatulence,constipation,and nausea/vomiting.Post-treatment,clinical outcomes are notably favorable,supporting the recommendation for treatment.Metronidazole is advocated as the first-line agent,with consideration for switching to a second-line option in cases of treatment failure or poor response.展开更多
Corn stalk cellulose(CS)/used rubber powder(RP)composites were prepared by mixing,the silane coupling agent 3-Mercaptopropyl trimethoxysilane(KH590),r-Aminopropyltrieth oxysilane(KH550),isopropyl dioleic(dioctylphosph...Corn stalk cellulose(CS)/used rubber powder(RP)composites were prepared by mixing,the silane coupling agent 3-Mercaptopropyl trimethoxysilane(KH590),r-Aminopropyltrieth oxysilane(KH550),isopropyl dioleic(dioctylphosphate)titanate(HY101)and bis-(γ-triethoxysilylpropyl)-tetrasulfide(Si69)were used to modify the interface of composites.The effects of the CS and coupling agents on the mechanical properties,thermal properties,interfacial morphology and structure of the composites were investigated,respectively.The results showed that the addition of CS could effectively improve the mechanical properties of the composites.Compared with the untreated composites,the interfacial bonding between CS and RP was significantly improved by the coupling modification treatment,and the tensile strength and elongation at break of composites with Si69 increased by 3.13 MPa and 10%,respectively,the Si69 showed the best coupling modification effect,followed by KH590,then KH550 and HY101 when the CS content was 25 pph(part per hundred)and coupling agent 1.5 pph,and the thermal decomposition temperature increased by 30℃.展开更多
Purpose: To investigate the efficacy and complications of continuous wear of etafilcon A for therapeutic use. Materials and Methods: The subjects were 228 eyes of 219 outpatients prescribed contact lens (CL) for one w...Purpose: To investigate the efficacy and complications of continuous wear of etafilcon A for therapeutic use. Materials and Methods: The subjects were 228 eyes of 219 outpatients prescribed contact lens (CL) for one week of continuous therapeutic wear during 10 years. The reason for prescription of CLs, the primary disease, the duration of CL wear and the complications were assessed retrospectively. Results: The predominant reason for prescription of CLs was relief of pain or a foreign-body sensation (62.3%) and protection of the corneal epithelium (20.6%). The primary disease was post-penetrating keratoplasty (36.8%), followed by corneal epithelial erosion (14.5%), post-lamellar keratoplasty (14.0%) and bullous keratopathy (12.2%). The average duration of wearing single lens was 6.5 ± 3.2 days. The average duration of wearing CLs in total was 9.2 ± 10.7 months. The most frequent problem associated with continuous wear of CLs was their dropping out of CLs (12.3%). The complications associated with CLs included conjunctivitis with papillary hyperplasia, corneal erosion and superficial punctate keratitis, but corneal ulcer and corneal infiltrates were not found. Conclusion: Serious complications were not shown changing the lenses every week to keep to the prescribed time limit for continuous therapeutic wear, even if corneal epithelial barrier function is impaired.展开更多
AIM To compare the long term effect of succimer (Suc) with that of penicillamine (Pen) in treating hepatolenticular degeneration (HLD). METHODS One hundred and twenty patients with HLD were divided into 2 groups. ...AIM To compare the long term effect of succimer (Suc) with that of penicillamine (Pen) in treating hepatolenticular degeneration (HLD). METHODS One hundred and twenty patients with HLD were divided into 2 groups. Group A ( n =60) received Suc 750mg , po. bid. Group B ( n =60) received Pen 250mg , po. qid. The period of maintenance treatment varied from 6 months to 3 years, averaging 1 5 years. Symptoms and therapeutic effects were evaluated by modified Goldstein scale. RESULTS The total effectiveness of group A in two different periods of treatment were 80% and 85% respectively, higher than those of group B (58% and 59% respectively) ( P <0 05). Suc also had obvious curative effects for the patients who failed in the use of Pen. There were fewer side effect in group A than in group B ( P <0 05). Suc and Pen could increase urinary copper excretion effectively and continually. CONCLUSION Suc is more effective and safer than Pen. Clinically, it can replace Pen as first choice drug for long term maintenance therapy of HLD.展开更多
Lymphadenectomy for urothelial carcinoma of the upper urinary tract has attracted the attention of physicians. The mapping study of lymphatic spread has shown that a relatively wide area should comprise the regional n...Lymphadenectomy for urothelial carcinoma of the upper urinary tract has attracted the attention of physicians. The mapping study of lymphatic spread has shown that a relatively wide area should comprise the regional nodes for tumors of the right renal pelvis or the right upper two-thirds of the ureter. A prospective study showed that an anatomical templatebased lymphadenectomy significantly improved patient survival in tumors of the renal pelvis. This benefit was more evident for patients with p T2 stage tumors or higher. The risk of regional node recurrence is significant reduced by template-based lymphadenectomy,which is likely to be associated with improved patient survival. The removal of lymph node micrometastases is assumed to be the reason for therapeutic benefit following lymphadenectomy. The number of resected lymph nodes can be used to assess the quality of lymphadenectomy,but not to determine the extent of lymphadenectomy. The guidelines currently recommend lymphadenectomy for patients with muscle-invasive disease,even though the current recommendation grades are still low. The present limitation of lymphadenectomy is the lack of standardization of the extent of lymphadenectomy and the randomized trials. Further studies are warranted to collect the evidence to support lymphadenectomy.展开更多
In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The ...In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The abrasive wear resistance of the composites layers were tested and compared with that of high chromium cast iron.The results show that the iron matrix composites with tungsten carbide particle have high hardness.The abrasive wear resistance of composites with tungsten carbide particle is higher than that of high chromium cast iron.The properties of the matrix materials have been improved remarkably.展开更多
The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles: ...The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles: micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.展开更多
The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those o...The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those obtained by singte edge notched beam (SENB) technique. Experimental results show that the KIC (IM) values calculated with different equations are quite different one from another. For composites without phase transformable components the KIC (IM) and KIC (SENB) values are practically on the same level, but for composites with phase transformable components (partially stabilized zirconia) the KIC (SENB) values are always higher than KIC (IM). This is because that the IM method can not reveal sensitively the toughening effect due to dynamic t-m transformation of ZrO2 as the SENB method does. The accuracy of the IM method depends on the Suitability of the IM equations and was evaluated for the materials used in this investigation. Two new IM equations are suggested with which the KIC (IM ) values can be obtained very close to KIC (SENB) values for composites having phase transformable components.展开更多
Fluorene is a polycyclic aromatic hydrocarbon, which is a hazardous toxic chemical in the environment. The measurement of low concentrations of fluorene is a subject of intense interest in chemistry and in the environ...Fluorene is a polycyclic aromatic hydrocarbon, which is a hazardous toxic chemical in the environment. The measurement of low concentrations of fluorene is a subject of intense interest in chemistry and in the environment. Polypyrrole chitosan cobalt ferrite nanoparticles are prepared using the electrochemical method. The prepared layers are characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The layers are used to detect fluorene using the surface plasmon resonance technique at room temperature. The composite layer is evaluated after detection of fluorene using atomic force microscopy. The fluorene is bound on the layer, and the shift of the resonance angle is about 0.0052°, corresponding to the limitation of 0.01 ppm.展开更多
Mesenchymal stem cells(MSCs)have tantalized regenerative medicine with their therapeutic potential,yet a cloud of controversies looms over their clinical tran-splantation.This comprehensive review navigates the intric...Mesenchymal stem cells(MSCs)have tantalized regenerative medicine with their therapeutic potential,yet a cloud of controversies looms over their clinical tran-splantation.This comprehensive review navigates the intricate landscape of MSC controversies,drawing upon 15 years of clinical experience and research.We delve into the fundamental properties of MSCs,exploring their unique immuno-modulatory capabilities and surface markers.The heart of our inquiry lies in the controversial applications of MSC transplantation,including the perennial debate between autologous and allogeneic sources,concerns about efficacy,and lingering safety apprehensions.Moreover,we unravel the enigmatic mechanisms surro-unding MSC transplantation,such as homing,integration,and the delicate balance between differentiation and paracrine effects.We also assess the current status of clinical trials and the ever-evolving regulatory landscape.As we peer into the future,we examine emerging trends,envisioning personalized medicine and innovative delivery methods.Our review provides a balanced and informed perspective on the controversies,offering readers a clear understanding of the complexities,challenges,and potential solutions in MSC transplantation.展开更多
Clinacanthus nutans Lindau is known as snake grass belonging to the Acanlhaceae family.This plant has diverse and potential medicinal uses in traditional herbal medicine for treating skin rashes,insects and snake bite...Clinacanthus nutans Lindau is known as snake grass belonging to the Acanlhaceae family.This plant has diverse and potential medicinal uses in traditional herbal medicine for treating skin rashes,insects and snake bites,lesions caused by herpes simplex virus,diabetes,and gout in Malaysia.Indonesia.Thailand and China.Phylochemieal investigations documented the varied contents of bioaclive compounds from litis plant namely flavonoids,glycosides,glycoglyeerolipids.cerebrosides and monoacylmonogalatosylglycerol.The pharmacological experiment proved that various types of extracts and pure compounds from this species exhibited a broad range of biological properties such as anti-inflammatory,antiviral,antioxidant,and anti-diabetic activities.The lindings of toxicity study showed that extracts from this plant did not show any toxicity thus it can be used as strong therapeutic agents for specific diseased conditions.However,further experiments on chemical components and their mode of action showing biological activities are required to elucidate the complete phytochemical profile and assess to confirm their suitability tor future drugs.This review summarizes the medicinal uses,phytochemistry and pharmacology of this plant in order to explore its therapeutic potential and gaps necessitating for prospected research work.展开更多
In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully (in Xiaojiang Basin, Yunnan) was conducted in 2004. Soil s...In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully (in Xiaojiang Basin, Yunnan) was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland (CL), forest bottomland (FL), and barren bottomland(BL). The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus (TP) and available phosphorus (AP), pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen (TN) and available nitrogen (AN) in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium (AK) in soil were positively correlated with soil particle.展开更多
基金supported by the National Natural Science Foundation of China(U22A20501)the National Key Research and Development Plan of China(2022YFD1500601)+4 种基金the National Science and Technology Fundamental Resources Investigation Program of China(2018FY100304)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA28090200)the Liaoning Province Applied Basic Research Plan Program,China(2022JH2/101300184)the Shenyang Science and Technology Plan Program,China(21-109-305)the Liaoning Outstanding Innovation Team,China(XLYC2008015)。
文摘Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,forest land and fallow land were investigated in six regions of northern China.Generic richness,diversity,abundance and biomass of soil nematodes was the lowest in crop land.The richness and diversity of soil nematodes were 28.8and 15.1%higher in fallow land than in crop land,respectively.No significant differences in soil nematode indices were found between forest land and fallow land,but their network keystone genera composition was different.Among the keystone genera,50%of forest land genera were omnivores-predators and 36%of fallow land genera were bacterivores.The proportion of fungivores in forest land was 20.8%lower than in fallow land.The network complexity and the stability were lower in crop land than forest land and fallow land.Soil pH,NH_(4)^(+)-N and NO_(3)^(–)-N were the major factors influencing the soil nematode community in crop land while soil organic carbon and moisture were the major factors in forest land.Soil nematode communities in crop land influenced by artificial management practices were more dependent on the soil environment than communities in forest land and fallow land.Land use induced soil environment variation and altered network relationships by influencing trophic group proportions among keystone nematode genera.
文摘Despite major achievements in the treatment ofchronic hepatitis C with the combination ofinterferons and the nucleoside analog ribavirin themajority of patients with chronic hepatitis C virus(HCV) infection cannot be treated effectively.Toimprove this response rate we used antisensetechnologies to inhibit HCV translation as possibleadditional option for experimental treatment.Antisense oligodeoxynucleotides(ODN) are
文摘The plant Aloe vera is used in Ayurvedic, Homoeopathic and Allopathic streams of medicine, and not only tribal community but also most of the people for food and medicine. The plant leaves contains numerous vitamins, minerals, enzymes, amino acids, natural sugars and other bioactive compounds with emollient, purgative, anti-microbial, anti inflammatory, antioxidant, aphrodisiac, anti-helmenthic, antifungal, antiseptic and cosmetic values for health care. This plant has potential to cure sunburns, burns and minor cuts, and even skin cancer. The external use in cosmetic primarily acts as skin healer and prevents injury of epithelial tissues, cures acne and gives a youthful glow to skin, also acts as extremely powerful laxative.
文摘BACKGROUND Blastocystis hominis(B.hominis),an anaerobic unicellular protist parasite,is known for its diverse clinical manifestations upon infecting the human gastrointestinal tract.Although globally distributed,it is particularly prevalent in developing nations.Examining the symptoms and treatment outcomes of B.hominis infection in low-resource settings holds immense significance,providing healthcare practi-tioners with valuable insights to enhance patient care.AIM To synthesize existing evidence on the symptomatology and treatment outcomes of B.hominis infection in low-resource settings.METHODS Following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines,a systematic review was conducted.The search spanned electronic databases including PubMed,Scopus,and Google Scholar.After a comprehensive screening process,a thorough examination of the papers,adhering to inclusion and exclusion criteria,and data extraction from eligible studies was conducted.The findings underwent summarization through simple descriptive analysis.RESULTS The search yielded 1200 papers,with 17 meeting inclusion criteria.Chronic diarrhea due to B.hominis infection was reported in only two studies,while abdominal pain,diarrhea,flatulence,constipation,and nausea/vomiting emerged as the most commonly documented symptoms.Recovery rates after one week of treatment ranged from 71.8%to 100%,and after two weeks,from 60%to 100%.CONCLUSION In low-resource settings,chronic diarrhea resulting from B.hominis infection is infrequent.Common symptoms include abdominal pain,diarrhea,flatulence,constipation,and nausea/vomiting.Post-treatment,clinical outcomes are notably favorable,supporting the recommendation for treatment.Metronidazole is advocated as the first-line agent,with consideration for switching to a second-line option in cases of treatment failure or poor response.
基金supported by 2019 Science and Graduate Innovative Research Project of Qiqihar University Heilongjiang Province,China(YJSCX2019060).
文摘Corn stalk cellulose(CS)/used rubber powder(RP)composites were prepared by mixing,the silane coupling agent 3-Mercaptopropyl trimethoxysilane(KH590),r-Aminopropyltrieth oxysilane(KH550),isopropyl dioleic(dioctylphosphate)titanate(HY101)and bis-(γ-triethoxysilylpropyl)-tetrasulfide(Si69)were used to modify the interface of composites.The effects of the CS and coupling agents on the mechanical properties,thermal properties,interfacial morphology and structure of the composites were investigated,respectively.The results showed that the addition of CS could effectively improve the mechanical properties of the composites.Compared with the untreated composites,the interfacial bonding between CS and RP was significantly improved by the coupling modification treatment,and the tensile strength and elongation at break of composites with Si69 increased by 3.13 MPa and 10%,respectively,the Si69 showed the best coupling modification effect,followed by KH590,then KH550 and HY101 when the CS content was 25 pph(part per hundred)and coupling agent 1.5 pph,and the thermal decomposition temperature increased by 30℃.
文摘Purpose: To investigate the efficacy and complications of continuous wear of etafilcon A for therapeutic use. Materials and Methods: The subjects were 228 eyes of 219 outpatients prescribed contact lens (CL) for one week of continuous therapeutic wear during 10 years. The reason for prescription of CLs, the primary disease, the duration of CL wear and the complications were assessed retrospectively. Results: The predominant reason for prescription of CLs was relief of pain or a foreign-body sensation (62.3%) and protection of the corneal epithelium (20.6%). The primary disease was post-penetrating keratoplasty (36.8%), followed by corneal epithelial erosion (14.5%), post-lamellar keratoplasty (14.0%) and bullous keratopathy (12.2%). The average duration of wearing single lens was 6.5 ± 3.2 days. The average duration of wearing CLs in total was 9.2 ± 10.7 months. The most frequent problem associated with continuous wear of CLs was their dropping out of CLs (12.3%). The complications associated with CLs included conjunctivitis with papillary hyperplasia, corneal erosion and superficial punctate keratitis, but corneal ulcer and corneal infiltrates were not found. Conclusion: Serious complications were not shown changing the lenses every week to keep to the prescribed time limit for continuous therapeutic wear, even if corneal epithelial barrier function is impaired.
文摘AIM To compare the long term effect of succimer (Suc) with that of penicillamine (Pen) in treating hepatolenticular degeneration (HLD). METHODS One hundred and twenty patients with HLD were divided into 2 groups. Group A ( n =60) received Suc 750mg , po. bid. Group B ( n =60) received Pen 250mg , po. qid. The period of maintenance treatment varied from 6 months to 3 years, averaging 1 5 years. Symptoms and therapeutic effects were evaluated by modified Goldstein scale. RESULTS The total effectiveness of group A in two different periods of treatment were 80% and 85% respectively, higher than those of group B (58% and 59% respectively) ( P <0 05). Suc also had obvious curative effects for the patients who failed in the use of Pen. There were fewer side effect in group A than in group B ( P <0 05). Suc and Pen could increase urinary copper excretion effectively and continually. CONCLUSION Suc is more effective and safer than Pen. Clinically, it can replace Pen as first choice drug for long term maintenance therapy of HLD.
文摘Lymphadenectomy for urothelial carcinoma of the upper urinary tract has attracted the attention of physicians. The mapping study of lymphatic spread has shown that a relatively wide area should comprise the regional nodes for tumors of the right renal pelvis or the right upper two-thirds of the ureter. A prospective study showed that an anatomical templatebased lymphadenectomy significantly improved patient survival in tumors of the renal pelvis. This benefit was more evident for patients with p T2 stage tumors or higher. The risk of regional node recurrence is significant reduced by template-based lymphadenectomy,which is likely to be associated with improved patient survival. The removal of lymph node micrometastases is assumed to be the reason for therapeutic benefit following lymphadenectomy. The number of resected lymph nodes can be used to assess the quality of lymphadenectomy,but not to determine the extent of lymphadenectomy. The guidelines currently recommend lymphadenectomy for patients with muscle-invasive disease,even though the current recommendation grades are still low. The present limitation of lymphadenectomy is the lack of standardization of the extent of lymphadenectomy and the randomized trials. Further studies are warranted to collect the evidence to support lymphadenectomy.
文摘In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The abrasive wear resistance of the composites layers were tested and compared with that of high chromium cast iron.The results show that the iron matrix composites with tungsten carbide particle have high hardness.The abrasive wear resistance of composites with tungsten carbide particle is higher than that of high chromium cast iron.The properties of the matrix materials have been improved remarkably.
文摘The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles: micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.
文摘The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those obtained by singte edge notched beam (SENB) technique. Experimental results show that the KIC (IM) values calculated with different equations are quite different one from another. For composites without phase transformable components the KIC (IM) and KIC (SENB) values are practically on the same level, but for composites with phase transformable components (partially stabilized zirconia) the KIC (SENB) values are always higher than KIC (IM). This is because that the IM method can not reveal sensitively the toughening effect due to dynamic t-m transformation of ZrO2 as the SENB method does. The accuracy of the IM method depends on the Suitability of the IM equations and was evaluated for the materials used in this investigation. Two new IM equations are suggested with which the KIC (IM ) values can be obtained very close to KIC (SENB) values for composites having phase transformable components.
文摘Fluorene is a polycyclic aromatic hydrocarbon, which is a hazardous toxic chemical in the environment. The measurement of low concentrations of fluorene is a subject of intense interest in chemistry and in the environment. Polypyrrole chitosan cobalt ferrite nanoparticles are prepared using the electrochemical method. The prepared layers are characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The layers are used to detect fluorene using the surface plasmon resonance technique at room temperature. The composite layer is evaluated after detection of fluorene using atomic force microscopy. The fluorene is bound on the layer, and the shift of the resonance angle is about 0.0052°, corresponding to the limitation of 0.01 ppm.
基金Supported by The National Recovery and Resilience Plan of the Republic of Bulgaria,No.BG-RRP-2.004-0008-C01.
文摘Mesenchymal stem cells(MSCs)have tantalized regenerative medicine with their therapeutic potential,yet a cloud of controversies looms over their clinical tran-splantation.This comprehensive review navigates the intricate landscape of MSC controversies,drawing upon 15 years of clinical experience and research.We delve into the fundamental properties of MSCs,exploring their unique immuno-modulatory capabilities and surface markers.The heart of our inquiry lies in the controversial applications of MSC transplantation,including the perennial debate between autologous and allogeneic sources,concerns about efficacy,and lingering safety apprehensions.Moreover,we unravel the enigmatic mechanisms surro-unding MSC transplantation,such as homing,integration,and the delicate balance between differentiation and paracrine effects.We also assess the current status of clinical trials and the ever-evolving regulatory landscape.As we peer into the future,we examine emerging trends,envisioning personalized medicine and innovative delivery methods.Our review provides a balanced and informed perspective on the controversies,offering readers a clear understanding of the complexities,challenges,and potential solutions in MSC transplantation.
文摘Clinacanthus nutans Lindau is known as snake grass belonging to the Acanlhaceae family.This plant has diverse and potential medicinal uses in traditional herbal medicine for treating skin rashes,insects and snake bites,lesions caused by herpes simplex virus,diabetes,and gout in Malaysia.Indonesia.Thailand and China.Phylochemieal investigations documented the varied contents of bioaclive compounds from litis plant namely flavonoids,glycosides,glycoglyeerolipids.cerebrosides and monoacylmonogalatosylglycerol.The pharmacological experiment proved that various types of extracts and pure compounds from this species exhibited a broad range of biological properties such as anti-inflammatory,antiviral,antioxidant,and anti-diabetic activities.The lindings of toxicity study showed that extracts from this plant did not show any toxicity thus it can be used as strong therapeutic agents for specific diseased conditions.However,further experiments on chemical components and their mode of action showing biological activities are required to elucidate the complete phytochemical profile and assess to confirm their suitability tor future drugs.This review summarizes the medicinal uses,phytochemistry and pharmacology of this plant in order to explore its therapeutic potential and gaps necessitating for prospected research work.
文摘In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully (in Xiaojiang Basin, Yunnan) was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland (CL), forest bottomland (FL), and barren bottomland(BL). The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus (TP) and available phosphorus (AP), pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen (TN) and available nitrogen (AN) in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium (AK) in soil were positively correlated with soil particle.