Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great pote...Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1β-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs’ size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.展开更多
AIM:To compare the impact of carbon dioxide(CO2) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy.METHODS:Patients referred for colonoscopy were randomized to receive ...AIM:To compare the impact of carbon dioxide(CO2) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy.METHODS:Patients referred for colonoscopy were randomized to receive either CO2 or air insufflation during the procedure.Both the colonoscopist and patient were blinded to the type of gas used.During the procedure,insertion and withdrawal times,caecal intubationrates,total sedation given and capnography readings were recorded.The level of sedation and magnitude of patient discomfort during the procedure was assessed by a nurse using a visual analogue scale(VAS)(0-3).Patients then graded their level of discomfort and abdominal bloating using a similar VAS.Complications during and after the procedure were recorded.RESULTS:A total of 142 patients were randomized with 72 in the air arm and 70 in the CO2 arm.Mean age between the two study groups were similar.Insertion time to the caecum was quicker in the CO2 group at 7.3 min vs 9.9 min with air(P = 0.0083).The average withdrawal times were not significantly different between the two groups.Caecal intubation rates were 94.4% and 100% in the air and CO2 groups respectively(P = 0.012).The level of discomfort assessed by the nurse was 0.69(air) and 0.39(CO2)(P = 0.0155) and by the patient 0.82(air) and 0.46(CO2)(P = 0.0228).The level of abdominal bloating was 0.97(air) and 0.36(CO2)(P = 0.001).Capnography readings trended to be higher in the CO2 group at the commencement,caecal intubation,and conclusion of the procedure,even though this was not significantly different when compared to readings obtained during air insufflation.There were no complications in both arms.CONCLUSION:CO2 insufflation during colonoscopy is more efficacious than air,allowing quicker and better cecal intubation rates.Abdominal discomfort and bloating were significantly less with CO2 insufflation.展开更多
AIM:To evaluate weight loss and surgical outcomes of Roux-en-Y gastric bypass(RYGB)and laparoscopic adjustable gastric band(LAGB).METHODS:Data relating to changes in body mass index(BMI)and procedural complications af...AIM:To evaluate weight loss and surgical outcomes of Roux-en-Y gastric bypass(RYGB)and laparoscopic adjustable gastric band(LAGB).METHODS:Data relating to changes in body mass index(BMI)and procedural complications after RYGB(1995-2009;n=609;116M:493F;42.4±0.4 years)or LAGB(2004-2009;n=686;131M:555F;37.2±0.4years)were extracted from prospective databases.RESULTS:Pre-operative BMI was higher in RYGB than LAGB patients(46.8±7.1 kg/m2vs 40.4±4.2 kg/m2,P<001);more patients with BMI<35 kg/m2underwent LAGB than RYGB(17.1%vs 4.1%,P<0.0001).BMI decrease was greater after RYGB.There were direct relationships between weight loss and pre-operative BMI(P<0.001).Although there was no difference in weight loss between genders during the first 3-year post-surgery,male LAGB patients had greater BMI reduction than females(-8.2±4.3 kg/m2vs-3.9±1.9kg/m2,P=0.02).Peri-operative complications occurred more frequently following RYGB than LAGB(8.0%vs0.5%,P<0.001);majority related to wound infection.LAGB had more long-term complications requiring corrective procedures than RYGB(8.9%vs 2.1%,P<0.001).Conversion to RYGB resulted in greater BMI reduction(-9.5±3.8 kg/m2)compared to removal and replacement of the band(-6.0±3.0 kg/m2).Twelve months post-surgery,fasting glucose,total cholesterol and low density lipoprotein levels were significantly lower with the magnitude of reduction greater in RYGB patients.CONCLUSION:RYGB produces substantially greater weight loss than LAGB.Whilst peri-operative complications are greater after RYGB,long-term complication rate is higher following LAGB.展开更多
Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macropha...Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macrophage system to protect themselves, plants instead use a multi-layered complex system termed the plant innate immunity, which recognizes pathogens and transducing downstream defense responses. They have developed a unique type of trans-membrane receptors or R proteins, which extracellularly, are capable of recognizing pathogen-associated molecular patterns (PAMP) such as flagellin and chitin, while intracellularly, they activate their harbored nucleotide cyclases (NCs) such as adenylyl cyclases (ACs), to generate second messenger molecules such as 3’,5’-cyclic adenosine monophosphate (cAMP), which then propagates and magnifies the defense response. To date, only a single R protein from Arabidopsis thaliana (AtLRR) has been shown to possess AC activity as well as having the ability to defend plants against infection by biotrophic and hemi-biotrophic pathogens. Therefore, in order to further broaden information around the functional roles of this protein (AtLRR), we explored it further, using an array of web-based tools or bioinformatics. These included structural analysis, anatomical expression analysis, developmental expression analysis, co-expression analysis, functional enrichment analysis, stimulus-specific expression analysis and promoter analysis. Findings from structural analysis showed that AtLRR is a multi-domain, trans-membrane molecule that is multi-functional, and thus consistent with all known R-proteins. Findings from anatomical and developmental expression analyses showed that AtLRR is mostly expressed in pollen grains and flowers, senescing leaves as well as during the development of seeds, shoots, roots, seedlings, leaves, flowers, and siliques, linking it to the three key plant physiological processes of reproduction, defense and development respectively. Lastly, findings from co-ex展开更多
Local communities in southern Africa derive many benefits from marula [Sclerocarya birrea（A.Rich.） Hochst.subsp.caffra（Sond.） Kokwaro].These include the contribution of this species towards health,nutrition,food s...Local communities in southern Africa derive many benefits from marula [Sclerocarya birrea（A.Rich.） Hochst.subsp.caffra（Sond.） Kokwaro].These include the contribution of this species towards health,nutrition,food security and conservation by sharing local skills and knowledge related to it.Marula fruits can be eaten fresh,squeezed to make juice,brewed in traditional beer or used to make jam and jelly.The kernels are also edible and can be pressed to extract oil for cooking and cosmetics,i.e.,for skin and hair application.The bark,roots,seeds and leaves are exploited for traditional medicinal purposes.Marula has acquired significant commercial value since its fruits and other products have entered local,regional and international trade in southern Africa.To diver-sify fruit production and satisfy the increasing demands for this resource,several domestication initiatives have been carried out at regional and international levels.The accumulated knowledge and skills relevant to the establishment and commercialization of marula therefore provide an effective guide in areas where marula remains undomesticated or underutilized.We discuss the great importance of marula in southern Africa to reveal its great potential to regions where it remains unexploited.展开更多
In order to identify the relationship between diurnal changes in the net photosynthetic rate（Pn） of Pueraria lobata and environmental factors,diurnal changes in the Pn of leaves of two P.lobata cultivars were measur...In order to identify the relationship between diurnal changes in the net photosynthetic rate（Pn） of Pueraria lobata and environmental factors,diurnal changes in the Pn of leaves of two P.lobata cultivars were measured using a CIRAS-1 portable photosynthesis measurement system（PP-Systems,UK）.The results show that diurnal changes in Pn of both cultivars could be interpreted as double-peak curves,indicating the occurrence of an obvious midday depression.Further analyses indicate that the correlation between Pn and stomatal conductance was positive and extremely significant（p 〈 0.01）.The correlations of Pn with intercellular CO2 concentration and transpiration rate were positive and significant（p 〈 0.05）,while the correlations of Pn with air and leaf temperatures were negative and significant（p 〈 0.05）.The results indicate that among the factors affecting photosynthetic properties,some can be grouped as stomatal limitations while others are non-stomatal limitations.展开更多
BACKGROUND Illness perception has long been hypothesized to be linked to psychological well-b eing in patients with rheumatic diseases,although substantial evidence is lacking,and the contribution of ruminative coping...BACKGROUND Illness perception has long been hypothesized to be linked to psychological well-b eing in patients with rheumatic diseases,although substantial evidence is lacking,and the contribution of ruminative coping style to this relationship is unclear.AIM To investigate the roles of illness perception and rumination in predicting fatigue and negative emotions in patients with chronic rheumatic diseases.METHODS Illness perception,rumination,fatigue and negative emotions(i.e.depression,anxiety and stress)were assessed by the Illness Perception Questionnaire-Revised,Stress Reactive Rumination Scale,Multidimensional Assessment of Fatigue,and the Depression,Anxiety and Stress Scale respectively.Multivariate regression analysis,the Sobel test,and the bootstrap were used to identify the mediating effect of rumination.RESULTS All five subscales of illness perception,including perceived illness identity,chronicity,cyclical nature,consequences and coherence of illness,were significantly associated with fatigue and negative emotions.In mediational analysis,rumination was found to mediate three components of illness perception(the identity,cyclical nature and consequences of illness)and negative emotions/fatigue.CONCLUSION Perceived identity,cyclical nature,and consequences of illness are significantly associated with fatigue and negative emotions in patients with chronic rheumatic diseases and these associations are mediated by rumination.Our findings suggest that psychological intervention should target rumination to improve physical and emotional well-being of patients with chronic rheumatic diseases.展开更多
Faidherbia albida is an ideal agroforestry tree commonly intercropped with annual crops like millet and groundnuts in the dry and densely populated areas of Africa. With its peculiar reverse phenology, it makes growth...Faidherbia albida is an ideal agroforestry tree commonly intercropped with annual crops like millet and groundnuts in the dry and densely populated areas of Africa. With its peculiar reverse phenology, it makes growth demands at a different time from that of crops. In addition, it deposits great amount of organic fertilizer on food crops. Leaves entering soils are comparable to fertilization of almost 50 t·ha^-1year^-1 of manure in dense stands of 50 large trees per ha. These nutrients help maximize agricultural production and reduce the need for a fallow period on poorer soils. Research has shown that millet grown under F. albida yielded 2.5 and 3.4 fold increases in grain and protein, respectively. Animals eat pods which contain mean amounts of crude protein of 20.63% and carbohydrate of 40.1% in seeds. Moreover, the continued existence ofF. albida in agroforestry parklands as in Ethiopia and Mali signifies the success of traditional conservation measures. Modem scientists have also developed much interest in the role of agroforestry in maintaining long-term biological balance between agriculture and livestock production systems. To ensure food security, which still remains a major challenge in sub-Saharan Africa, and concurrently minimize environmental degradation, promotion of agroforestry that specifically involves indigenous trees is crucial. We discuss the prospective role ofF. albida in alleviating poverty while simultaneously protecting the environment from factors associated with, for example, deforestation and loss of biodiversity. The overall aim is to promote wide-scale adoption ofF. albida as a valuable tree crop in farming systems, particularly in those areas where it remains unexploited.展开更多
To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength,degree of conversion,along with resin infiltration within the dem...To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength,degree of conversion,along with resin infiltration within the demineralized dentin substrate,an experimental adhesive-system was modified with different concentrations of riboflavin（mlm,0,1%,3%,5%and 10%）.Dentin surfaces were etched with 37%phosphoric acid,bonded with respective adhesives,restored with restorative composite-resin,and sectioned into resin-dentin slabs and beams to be stored for 24 h or 9 months in artificial saliva.Micro-tensile bond testing was performed with scanning electron microscopy to analyse the failure of debonded beams.The degree of conversion was evaluated with Fourier transform infrared spectroscopy（FTIR） at different time points along with micro-Raman spectroscopy analysis.Data was analyzed with one-way and two-way analysis of variance followed by Tukey＇s for pair-wise comparison.Modification with 1%and 3%riboflavin increased the micro-tensile bond strength compared to the control at 24 h and 9-month storage with no significant differences in degree of conversion（P〈0.05）.The most predominant failure mode was the mixed fracture among all specimens except 10%riboflavin-modified adhesive specimens where cohesive failure was predominant.Raman analysis revealed that 1%and 3%riboflavin adhesives specimens showed relatively higher resin infiltration.The incorporation of riboflavin in the experimental two-step etch-and-rinse adhesive at 3%（mlm） improved the immediate bond strengths and bond durability after 9-month storage in artificial saliva without adversely affecting the degree of conversion of the adhesive monomers and resin infiltration.展开更多
基金supported by National Medical Research Council of Singapore(MOH-000371-00)the National Research Foundation,Prime Minister’s Office,Singapore under its Campus for Research Excellence and Technological Enterprise(CREATE)program,through Singapore-MIT Alliance for Research and Technology(SMART):Critical Analytics for Manufacturing Personalized-Medicine(CAMP)Inter-Disciplinary Research Group.YY was supported by NUS Research Scholarship.
文摘Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1β-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs’ size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.
文摘AIM:To compare the impact of carbon dioxide(CO2) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy.METHODS:Patients referred for colonoscopy were randomized to receive either CO2 or air insufflation during the procedure.Both the colonoscopist and patient were blinded to the type of gas used.During the procedure,insertion and withdrawal times,caecal intubationrates,total sedation given and capnography readings were recorded.The level of sedation and magnitude of patient discomfort during the procedure was assessed by a nurse using a visual analogue scale(VAS)(0-3).Patients then graded their level of discomfort and abdominal bloating using a similar VAS.Complications during and after the procedure were recorded.RESULTS:A total of 142 patients were randomized with 72 in the air arm and 70 in the CO2 arm.Mean age between the two study groups were similar.Insertion time to the caecum was quicker in the CO2 group at 7.3 min vs 9.9 min with air(P = 0.0083).The average withdrawal times were not significantly different between the two groups.Caecal intubation rates were 94.4% and 100% in the air and CO2 groups respectively(P = 0.012).The level of discomfort assessed by the nurse was 0.69(air) and 0.39(CO2)(P = 0.0155) and by the patient 0.82(air) and 0.46(CO2)(P = 0.0228).The level of abdominal bloating was 0.97(air) and 0.36(CO2)(P = 0.001).Capnography readings trended to be higher in the CO2 group at the commencement,caecal intubation,and conclusion of the procedure,even though this was not significantly different when compared to readings obtained during air insufflation.There were no complications in both arms.CONCLUSION:CO2 insufflation during colonoscopy is more efficacious than air,allowing quicker and better cecal intubation rates.Abdominal discomfort and bloating were significantly less with CO2 insufflation.
文摘AIM:To evaluate weight loss and surgical outcomes of Roux-en-Y gastric bypass(RYGB)and laparoscopic adjustable gastric band(LAGB).METHODS:Data relating to changes in body mass index(BMI)and procedural complications after RYGB(1995-2009;n=609;116M:493F;42.4±0.4 years)or LAGB(2004-2009;n=686;131M:555F;37.2±0.4years)were extracted from prospective databases.RESULTS:Pre-operative BMI was higher in RYGB than LAGB patients(46.8±7.1 kg/m2vs 40.4±4.2 kg/m2,P<001);more patients with BMI<35 kg/m2underwent LAGB than RYGB(17.1%vs 4.1%,P<0.0001).BMI decrease was greater after RYGB.There were direct relationships between weight loss and pre-operative BMI(P<0.001).Although there was no difference in weight loss between genders during the first 3-year post-surgery,male LAGB patients had greater BMI reduction than females(-8.2±4.3 kg/m2vs-3.9±1.9kg/m2,P=0.02).Peri-operative complications occurred more frequently following RYGB than LAGB(8.0%vs0.5%,P<0.001);majority related to wound infection.LAGB had more long-term complications requiring corrective procedures than RYGB(8.9%vs 2.1%,P<0.001).Conversion to RYGB resulted in greater BMI reduction(-9.5±3.8 kg/m2)compared to removal and replacement of the band(-6.0±3.0 kg/m2).Twelve months post-surgery,fasting glucose,total cholesterol and low density lipoprotein levels were significantly lower with the magnitude of reduction greater in RYGB patients.CONCLUSION:RYGB produces substantially greater weight loss than LAGB.Whilst peri-operative complications are greater after RYGB,long-term complication rate is higher following LAGB.
文摘Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macrophage system to protect themselves, plants instead use a multi-layered complex system termed the plant innate immunity, which recognizes pathogens and transducing downstream defense responses. They have developed a unique type of trans-membrane receptors or R proteins, which extracellularly, are capable of recognizing pathogen-associated molecular patterns (PAMP) such as flagellin and chitin, while intracellularly, they activate their harbored nucleotide cyclases (NCs) such as adenylyl cyclases (ACs), to generate second messenger molecules such as 3’,5’-cyclic adenosine monophosphate (cAMP), which then propagates and magnifies the defense response. To date, only a single R protein from Arabidopsis thaliana (AtLRR) has been shown to possess AC activity as well as having the ability to defend plants against infection by biotrophic and hemi-biotrophic pathogens. Therefore, in order to further broaden information around the functional roles of this protein (AtLRR), we explored it further, using an array of web-based tools or bioinformatics. These included structural analysis, anatomical expression analysis, developmental expression analysis, co-expression analysis, functional enrichment analysis, stimulus-specific expression analysis and promoter analysis. Findings from structural analysis showed that AtLRR is a multi-domain, trans-membrane molecule that is multi-functional, and thus consistent with all known R-proteins. Findings from anatomical and developmental expression analyses showed that AtLRR is mostly expressed in pollen grains and flowers, senescing leaves as well as during the development of seeds, shoots, roots, seedlings, leaves, flowers, and siliques, linking it to the three key plant physiological processes of reproduction, defense and development respectively. Lastly, findings from co-ex
基金supported by the "948" Project of State Forestry Administration of China (Grant No. 2011-4-43) the National Science and Technology Major Project of China (Grant No. 2009ZX09308-002)
文摘Local communities in southern Africa derive many benefits from marula [Sclerocarya birrea（A.Rich.） Hochst.subsp.caffra（Sond.） Kokwaro].These include the contribution of this species towards health,nutrition,food security and conservation by sharing local skills and knowledge related to it.Marula fruits can be eaten fresh,squeezed to make juice,brewed in traditional beer or used to make jam and jelly.The kernels are also edible and can be pressed to extract oil for cooking and cosmetics,i.e.,for skin and hair application.The bark,roots,seeds and leaves are exploited for traditional medicinal purposes.Marula has acquired significant commercial value since its fruits and other products have entered local,regional and international trade in southern Africa.To diver-sify fruit production and satisfy the increasing demands for this resource,several domestication initiatives have been carried out at regional and international levels.The accumulated knowledge and skills relevant to the establishment and commercialization of marula therefore provide an effective guide in areas where marula remains undomesticated or underutilized.We discuss the great importance of marula in southern Africa to reveal its great potential to regions where it remains unexploited.
基金supported by the "Eleventh Five-year" National Science and Technology Support Program of China (Grant No. 2009BADA7B04 Grant No. 2008BAD95B03the National Science and Technology Major Project of China (Grant No. 2009ZX09308-002)
文摘In order to identify the relationship between diurnal changes in the net photosynthetic rate（Pn） of Pueraria lobata and environmental factors,diurnal changes in the Pn of leaves of two P.lobata cultivars were measured using a CIRAS-1 portable photosynthesis measurement system（PP-Systems,UK）.The results show that diurnal changes in Pn of both cultivars could be interpreted as double-peak curves,indicating the occurrence of an obvious midday depression.Further analyses indicate that the correlation between Pn and stomatal conductance was positive and extremely significant（p 〈 0.01）.The correlations of Pn with intercellular CO2 concentration and transpiration rate were positive and significant（p 〈 0.05）,while the correlations of Pn with air and leaf temperatures were negative and significant（p 〈 0.05）.The results indicate that among the factors affecting photosynthetic properties,some can be grouped as stomatal limitations while others are non-stomatal limitations.
文摘BACKGROUND Illness perception has long been hypothesized to be linked to psychological well-b eing in patients with rheumatic diseases,although substantial evidence is lacking,and the contribution of ruminative coping style to this relationship is unclear.AIM To investigate the roles of illness perception and rumination in predicting fatigue and negative emotions in patients with chronic rheumatic diseases.METHODS Illness perception,rumination,fatigue and negative emotions(i.e.depression,anxiety and stress)were assessed by the Illness Perception Questionnaire-Revised,Stress Reactive Rumination Scale,Multidimensional Assessment of Fatigue,and the Depression,Anxiety and Stress Scale respectively.Multivariate regression analysis,the Sobel test,and the bootstrap were used to identify the mediating effect of rumination.RESULTS All five subscales of illness perception,including perceived illness identity,chronicity,cyclical nature,consequences and coherence of illness,were significantly associated with fatigue and negative emotions.In mediational analysis,rumination was found to mediate three components of illness perception(the identity,cyclical nature and consequences of illness)and negative emotions/fatigue.CONCLUSION Perceived identity,cyclical nature,and consequences of illness are significantly associated with fatigue and negative emotions in patients with chronic rheumatic diseases and these associations are mediated by rumination.Our findings suggest that psychological intervention should target rumination to improve physical and emotional well-being of patients with chronic rheumatic diseases.
文摘Faidherbia albida is an ideal agroforestry tree commonly intercropped with annual crops like millet and groundnuts in the dry and densely populated areas of Africa. With its peculiar reverse phenology, it makes growth demands at a different time from that of crops. In addition, it deposits great amount of organic fertilizer on food crops. Leaves entering soils are comparable to fertilization of almost 50 t·ha^-1year^-1 of manure in dense stands of 50 large trees per ha. These nutrients help maximize agricultural production and reduce the need for a fallow period on poorer soils. Research has shown that millet grown under F. albida yielded 2.5 and 3.4 fold increases in grain and protein, respectively. Animals eat pods which contain mean amounts of crude protein of 20.63% and carbohydrate of 40.1% in seeds. Moreover, the continued existence ofF. albida in agroforestry parklands as in Ethiopia and Mali signifies the success of traditional conservation measures. Modem scientists have also developed much interest in the role of agroforestry in maintaining long-term biological balance between agriculture and livestock production systems. To ensure food security, which still remains a major challenge in sub-Saharan Africa, and concurrently minimize environmental degradation, promotion of agroforestry that specifically involves indigenous trees is crucial. We discuss the prospective role ofF. albida in alleviating poverty while simultaneously protecting the environment from factors associated with, for example, deforestation and loss of biodiversity. The overall aim is to promote wide-scale adoption ofF. albida as a valuable tree crop in farming systems, particularly in those areas where it remains unexploited.
基金supported,in part,by the Ministry of Education,Singapore,NUS/ARF grants R221000039133 and R221000052112
文摘To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength,degree of conversion,along with resin infiltration within the demineralized dentin substrate,an experimental adhesive-system was modified with different concentrations of riboflavin（mlm,0,1%,3%,5%and 10%）.Dentin surfaces were etched with 37%phosphoric acid,bonded with respective adhesives,restored with restorative composite-resin,and sectioned into resin-dentin slabs and beams to be stored for 24 h or 9 months in artificial saliva.Micro-tensile bond testing was performed with scanning electron microscopy to analyse the failure of debonded beams.The degree of conversion was evaluated with Fourier transform infrared spectroscopy（FTIR） at different time points along with micro-Raman spectroscopy analysis.Data was analyzed with one-way and two-way analysis of variance followed by Tukey＇s for pair-wise comparison.Modification with 1%and 3%riboflavin increased the micro-tensile bond strength compared to the control at 24 h and 9-month storage with no significant differences in degree of conversion（P〈0.05）.The most predominant failure mode was the mixed fracture among all specimens except 10%riboflavin-modified adhesive specimens where cohesive failure was predominant.Raman analysis revealed that 1%and 3%riboflavin adhesives specimens showed relatively higher resin infiltration.The incorporation of riboflavin in the experimental two-step etch-and-rinse adhesive at 3%（mlm） improved the immediate bond strengths and bond durability after 9-month storage in artificial saliva without adversely affecting the degree of conversion of the adhesive monomers and resin infiltration.
