Introduction:Early childhood development(ECD)centres are important community hubs in South Africa and act as sites for community detection of childhood nutrition problems.This study aimed to assess the ability of trai...Introduction:Early childhood development(ECD)centres are important community hubs in South Africa and act as sites for community detection of childhood nutrition problems.This study aimed to assess the ability of trained ECD practitioners with optimal support to correctly classify the nutritional status of infants and young children at ECD centres in the Nelson Mandela Bay.Methods:A descriptive,cross-sectional study was used to collect data from 1645 infants and children at 88 ECD centres.Anthropometric measurements were taken by trained fieldworkers and growth monitoring and promotion infrastructure was audited at ECD centres.Results:Of the sample,4.4%(n=72)were underweight by weight for age Z-score(WAZ<-2)and 0.8%(n=13)were severely underweight(WAZ<-3).Results showed that 13.1%(n=214)were stunted by height for age Z-score(HAZ<-2)and 4.5%(n=74)were severely stunted(HAZ<-3).The prevalence of moderate acute malnutrition was 1.2%and severe acute malnutrition was 0.5%,while the prevalence of overweight was 9.2%and the prevalence of obesity was 4%.A significant level of agreement between the correct interpretation and the ECD practitioners'interpretation was observed across all the anthropometric indicators investigated.The true positive wasting cases had a mean mid-upper arm circumference(MUAC)of 14.6 cm,which may explain the high false negative rate found in terms of children identified with wasting,where ECD practitioners fail to use the weight for height Z-score(WHZ)interpretation for screening.Conclusion:By using ECD centres as hub to screen for malnutrition,it may contribute to the early identification of failure to thrive among young children.Although it was concerning that trained ECD practitioners are missing some children with an unacceptably high false negative rate,it may have been due to the fact that wasting in older children cannot be identified with MUAC alone and that accurate WFH plotting is needed.Onsite mentorship by governmental health workers may provide ECD practitioners with more confidence to screen children for growth failure based on regular WFH measurements.Moreover,ECD practitioners will be more confident to monitor the Road to Health booklets for missed vaccinations,vitamin A and deworming opportunities.展开更多
Melt blending of biodegradable polyesters such as poly(lactic acid)(PLA)and poly(butylene adipate co-terephthalate)(PBAT)with a compatibilizer and natural filler offers a chance to develop biodegradable biocomposites ...Melt blending of biodegradable polyesters such as poly(lactic acid)(PLA)and poly(butylene adipate co-terephthalate)(PBAT)with a compatibilizer and natural filler offers a chance to develop biodegradable biocomposites with improved performance.In this study,we examined how PLA/PBAT blends behave during ultimate biodegradation(mineralization),both with and without compatibilizer and algae as a reinforcement,under controlled composting conditions using carbon dioxide(CO_(2))respirometry techniques.Throughout the biodegradation process,the disintegration behaviour,thermal,chemical,and morphological properties of test samples before and after biodegradation were analyzed using FTIR,TGA,DSC,and SEM techniques.The results from CO_(2)biodegradation showed that PLA/PBAT blend exhibits a higher rate of biodegradation compared to neat PLA and PBAT.The addition of algae to a compatibilized PLA/PBAT blend showed an enhanced biodegradation rate due to hydrolytic cleavage and microbial assimilation.This was further supported by the disintegration test,where algae-reinforced composites showed fragmentation within 30 days.FTIR,TGA and SEM analysis revealed the structural changes that occurred during biodegradation,highlighting the role of algae in affecting the thermal stability and surface morphology.After the compost biodegradation step,eco-toxicity seed germination was conducted on the test samples.Plant seed germination test results confirmed that all test samples achieved maximumgermination.This indicates there were no toxic residues,suggesting that the degraded materials are environmentally safe.Overall,this study contributes to the understanding of biodegradation mechanisms and the ecological impact of bio-based polymer composites as eco-friendly materials and products.展开更多
Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been rep...Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been reported to be effective in managing crop pests, and a number of them have been formulated and commercialized. This study was conducted in North-Eastern Tanzania to establish the pesticidal and medicinal value of turmeric (Curcuma longa) and ginger (Zingiber officinale). Purposive sampling was adopted to select and interview 167 respondents drawn from farmers, traders, pharmaceutical shops, agro-shop operators and consumers of turmeric and ginger. Ginger and turmeric rhizomes were also collected for extraction, antifungal assay and biochemical analysis. Results showed that majority of the respondents were aware of the medicinal value of ginger and turmeric, with 59.5% having used the plants to treat respiratory related infections and healing skin surface and internal wounds. About 14% of farmers were aware of and had used aqueous botanical preparations from neem, moringa and Tephrosia to manage insect pests. Only 2.7% of farmers had used ginger powder as a protective insecticide on stored grains. Ginger and turmeric rhizome extracts showed high antifungal activity against Pythium (83% - 95%), Fusarium oxysporum f. sp. lycopersici (34% - 52%) and Alternaria solani (38% - 53%). A GC-MS analysis of ginger and turmeric extracts showed presence of α-zingiberene, β-sesquiphellandrene, α-farnesene, ar-curcumene, α-copaene, ar-tumerone and curlone. This study recommends that ginger and turmeric extracts be considered for development of a botanical pesticide and especially for management of damping off diseases.展开更多
1.Introduction As global temperatures increase and weather patterns grow more er-ratic,the urgency of adopting climate-smart conservation strategies has intensified(Manyakaidze et al.,2024).Climate-smart conservation ...1.Introduction As global temperatures increase and weather patterns grow more er-ratic,the urgency of adopting climate-smart conservation strategies has intensified(Manyakaidze et al.,2024).Climate-smart conservation com-prises adaptive management practices aimed at bolstering the resilience of ecosystems and species amid climate variability(Birchall et al.,2021;Gabriel-Campos et al.,2021).展开更多
The pathogenesis of insulin resistance is influenced by environmental factors,genetic predispositions,and several medications.Various drugs used to managemultiple ailments have been shown to induce insulin resistance,...The pathogenesis of insulin resistance is influenced by environmental factors,genetic predispositions,and several medications.Various drugs used to managemultiple ailments have been shown to induce insulin resistance,which could lead to Type II Diabetes mellitus(T2DM).Central to drug-induced insulin resistance is mitochondrial dysfunction.Amongst disturbed pathways in drug-inducedmitochondrial toxicity is mitophagy,a process that removes dysfunctionalmitochondria through the lysosomal pathways to maintain mitochondrial quality.A balancemust always be maintained between mitochondrial dynamics and mitophagy,as any alterations may contribute to the pathogenesis of metabolic diseases such as diabetes mellitus.If damaged mitochondria are not removed,their accumulation leads to increased production of reactive oxygen species(ROS)and release of calcium and cytochrome C,which leads to apoptosis.This review paper focuses on the implications of the mitophagy initiation pathways,such as Adenosine Monophosphate-activated Protein Kinase/Mammalian Target of Rapamycin(AMPK/mTOR),PTEN-induced kinase 1,and Parkin RBR E3 ubiquitin-protein ligase,PINK/Parkin,and the receptor-mediated pathways,such as FUN14 domain containing 1(FUNDC1)and Bcl-2 interacting protein 3(BNIP3/NIX),as a crucial link between drug-induced mitochondrial dysfunction and insulin sensitivity impairment.It also focuses on the implications of mitochondrial dynamics in drug-induced insulin impairments.Pharmacological agents such as simvastatin,clarithromycin,olanzapine,and dexamethasone have been investigated and shown to induce insulin resistance in part through altered mitochondrial function.In this review paper,we further illuminate disturbances in mitophagy and mitochondrial dynamics that could also be pivotal in insulin resistance development as a result of exposure to these drugs.Mitophagy and mitochondrial dynamics remain understudied.Exploring the implications of mitophagy pathways and mitochondrial dynamics on drug-induced insulin resistance could lead to the development of new approaches that can be used to mitigate insulin resistance associated with different classes of pharmacological modalities.展开更多
The Agulhas Current is a major western boundary current flowing polewards on the southeast coast of South Africa.This analysis assesses its characteristics and suitability to generate power as a source of clean renewa...The Agulhas Current is a major western boundary current flowing polewards on the southeast coast of South Africa.This analysis assesses its characteristics and suitability to generate power as a source of clean renewable energy.On a section of coastline some 400 km long,over a period spanning more than 5 years an extensive set of current measurements was obtained.These data confirmed that south-westward currents with a speed greater than 1.2 m s^(-1)occurred over more than 60%of the recorded time;such ocean current speeds compare very favourably to winds required for energy generation.These currents occurred at the continental shelf break in water depths around 100 m,in the upper 50 m of the water column.Occasional current slowdowns and reversals did occur,with the major influence coming from‘Natal Pulses’,which are large-scale meanders in the Current that temporarily reversed the currents at the measurement sites.However,because of the surface temperature structure of the relevant water masses,such meanders can be identified in satellite imagery giving a few days advance warning of such current reversals.The characteristics of western boundary currents have been known for many years,but at Present,there is no operational system where this source of power is being utilised.It has tremendous potential for renewable energy generation,but is symptomatic of the many engineering challenges that still have to be solved to make such generation economically viable.展开更多
Effective antifouling coatings are critical for protecting marine infrastructure from biofouling and environmental degradation;however,achieving long-term antifouling performance along with environmental stability rem...Effective antifouling coatings are critical for protecting marine infrastructure from biofouling and environmental degradation;however,achieving long-term antifouling performance along with environmental stability remains a major challenge.In this study,a multifunctional bio-based epoxy coating is developed by integrating a dual-action antifouling system.Cinnamic acid(CA),which is known for its antibacterial and UV-shielding properties,was chemically grafted into ethylene glycol diglycidyl ether(EGDE)to provide intrinsic antifouling and anti-UV functions.Simultaneously,the KH560-modified silica aerogel was incorporated to create a dense hydrophobic surface that repels microorganism adhesion.The resulting coating exhibited a superhydrophobic contact angle of 154.3°,an ultralow surface energy,and exceptional resistance to protein and algal adhesion.Additionally,it achieves 99%bactericidal efficiency against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)while maintaining high transparency and ease of processing.These results highlight a promising strategy for designing durable and ecofriendly antifouling coatings suitable for demanding marine environments.展开更多
The prevailing consensus in statistical literature is that multiple imputation is generally the most suitable method for addressing missing data in statistical analyses,whereas a complete case analysis is deemed appro...The prevailing consensus in statistical literature is that multiple imputation is generally the most suitable method for addressing missing data in statistical analyses,whereas a complete case analysis is deemed appropriate only when the rate of missingness is negligible or when the missingness mechanism is missing completely at random(MCAR).This study investigates the applicability of this consensus within the context of supervised machine learning,with particular emphasis on the interactions between the imputation method,missingness mechanism,and missingness rate.Furthermore,we examine the time efficiency of these“state-of-the-art”imputation methods considering the time-sensitive nature of certain machine learning applications.Utilizing ten real-world datasets,we introduced missingness at rates ranging from approximately 5%–75%under the MCAR,missing at random(MAR),and missing not at random(MNAR)mechanisms.We subsequently address missing data using five methods:complete case analysis(CCA),mean imputation,hot deck imputation,regression imputation,and multiple imputation(MI).Statistical tests are conducted on the machine learning outcomes,and the findings are presented and analyzed.Our investigation reveals that in nearly all scenarios,CCA performs comparably to MI,even with substantial levels of missingness under the MAR and MNAR conditions and with missingness in the output variable for regression problems.Under some conditions,CCA surpasses MI in terms of its performance.Thus,given the considerable computational demands associated with MI,the application of CCA is recommended within the broader context of supervised machine learning,particularly in big-data environments.展开更多
Background:Congenital cardiac diseases(CCD)are common congenital birth defects that require high-risk surgery.Outcomes following congenital cardiac surgery in children living in high-income countries(HIC)have been doc...Background:Congenital cardiac diseases(CCD)are common congenital birth defects that require high-risk surgery.Outcomes following congenital cardiac surgery in children living in high-income countries(HIC)have been documented,but little is known from the African continent.This study aimed to determine factors associated with perioperative mortality in patients who underwent congenital cardiac surgery at our institution.Methods:This retrospective,cross-sectional study was conducted at Charlotte Maxeke Johannesburg Academic Hospital over 12 years(2006–2017).A multivariable regression analysis was performed for the factors which had a p-value of 0.1 and less in the univariable regression analysis.A Cox regression analysis was performed for mortality over time.All hypothesis testing accepted a p-value of<0.05 as statistically signiffcant.Results:There was an 11%(188/1701)in-hospital mortality rate overall.Patients who had a median age of 0.33 years(interquartile range[IQR]0.13–1.25),weight of 5 kg(IQR 3.45–8.20),longer cardiopulmonary bypass(CPB)of 179 min(16.0–275.5)and aortic cross-clamp of 82.5 min(35–139)were at greater risk of in-hospital mortality.Palliative surgeries had the highest in-hospital mortality rate at 41%.Cardiopulmonary bypass time(p<0.001),ICU length of stay(p<0.001),aortic cross-clamp time(p=0.001)and days on the ventilator(p<0.001)were independently predictive of perioperative all-cause in-hospital mortality in a multivariable regression model.Current predictive scoring systems had inconsistent performance,with the STAT 2020 mortality score being predictive in a multivariable regression analysis(p=0.038)and the RACHS-2 score in a Cox regression analysis(p=0.002).Conclusions:Perioperative mortality following congenital cardiac surgery was higher in our study group compared to HICs.Future prospective studies are required to highlight the need to prioritise and invest in the declining services provided to children with CCD in South Africa’s public sector.展开更多
The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development ...The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications.Besides its biodegradability,PBS can be derived from petroleum and biobased monomers.At the same time,the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products.The processes and techniques presented herein,are based on the production of biobased succinic acid monomer to PBS.However,the counterpart biobased monomer 1,4-butanediol(1,4-BDO)production has not been commercially demonstrated.This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS,its copolymers,and composites with the view to improve molecular weight,thermal,and mechanical properties.It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical,thermal,stability and mechanical structural properties.Importantly,the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films,biomedical and drug release,fire retardants,and agricultural products.The structure-functional performance characteristics of these developments in the PBS,copolymers,and composites are highlighted to provide baseline insights for future developments in engineering the specific applications,and structural interface PBS composites with enhanced structure-functional performance properties.展开更多
This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening a...This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening agribusiness networks and improving livelihoods.Data was collected from 215 farmers and 320 traders through a multistage sampling procedure.Heckman AI sample selection model was used in data analysis whereby the findings showed key factors influencing farmers’decisions on ecology were gender and years of formal education at p<0.1,and access to finance and off-farm income at p<0.05.The degree of farmers participation in social groups was influenced by age,household size,off-farm income and business network at p<0.05,number of years in formal education and access to finance at p<0.01,and distance to the market at p<0.1.The decision of traders to impact on ecology was significantly influenced by age and trading experience at p<0.1.Meanwhile,the degree of their involvement in social groups was strongly affected by gender,formal education,and trust at p<0.01,as well as by access to finance and business networks at p<0.05.The study concluded that natural ecology is influenced by socio economic and structural factors but trust among group members determine the degree of participation.The study recommends that strategies to improve agribusiness networks should understand underlying causes of impact on ecology and strengthen available social groups to improve performance of farmers and traders.展开更多
基金Nelson Mandela University,London Metropolitan University and UNICEF。
文摘Introduction:Early childhood development(ECD)centres are important community hubs in South Africa and act as sites for community detection of childhood nutrition problems.This study aimed to assess the ability of trained ECD practitioners with optimal support to correctly classify the nutritional status of infants and young children at ECD centres in the Nelson Mandela Bay.Methods:A descriptive,cross-sectional study was used to collect data from 1645 infants and children at 88 ECD centres.Anthropometric measurements were taken by trained fieldworkers and growth monitoring and promotion infrastructure was audited at ECD centres.Results:Of the sample,4.4%(n=72)were underweight by weight for age Z-score(WAZ<-2)and 0.8%(n=13)were severely underweight(WAZ<-3).Results showed that 13.1%(n=214)were stunted by height for age Z-score(HAZ<-2)and 4.5%(n=74)were severely stunted(HAZ<-3).The prevalence of moderate acute malnutrition was 1.2%and severe acute malnutrition was 0.5%,while the prevalence of overweight was 9.2%and the prevalence of obesity was 4%.A significant level of agreement between the correct interpretation and the ECD practitioners'interpretation was observed across all the anthropometric indicators investigated.The true positive wasting cases had a mean mid-upper arm circumference(MUAC)of 14.6 cm,which may explain the high false negative rate found in terms of children identified with wasting,where ECD practitioners fail to use the weight for height Z-score(WHZ)interpretation for screening.Conclusion:By using ECD centres as hub to screen for malnutrition,it may contribute to the early identification of failure to thrive among young children.Although it was concerning that trained ECD practitioners are missing some children with an unacceptably high false negative rate,it may have been due to the fact that wasting in older children cannot be identified with MUAC alone and that accurate WFH plotting is needed.Onsite mentorship by governmental health workers may provide ECD practitioners with more confidence to screen children for growth failure based on regular WFH measurements.Moreover,ECD practitioners will be more confident to monitor the Road to Health booklets for missed vaccinations,vitamin A and deworming opportunities.
文摘Melt blending of biodegradable polyesters such as poly(lactic acid)(PLA)and poly(butylene adipate co-terephthalate)(PBAT)with a compatibilizer and natural filler offers a chance to develop biodegradable biocomposites with improved performance.In this study,we examined how PLA/PBAT blends behave during ultimate biodegradation(mineralization),both with and without compatibilizer and algae as a reinforcement,under controlled composting conditions using carbon dioxide(CO_(2))respirometry techniques.Throughout the biodegradation process,the disintegration behaviour,thermal,chemical,and morphological properties of test samples before and after biodegradation were analyzed using FTIR,TGA,DSC,and SEM techniques.The results from CO_(2)biodegradation showed that PLA/PBAT blend exhibits a higher rate of biodegradation compared to neat PLA and PBAT.The addition of algae to a compatibilized PLA/PBAT blend showed an enhanced biodegradation rate due to hydrolytic cleavage and microbial assimilation.This was further supported by the disintegration test,where algae-reinforced composites showed fragmentation within 30 days.FTIR,TGA and SEM analysis revealed the structural changes that occurred during biodegradation,highlighting the role of algae in affecting the thermal stability and surface morphology.After the compost biodegradation step,eco-toxicity seed germination was conducted on the test samples.Plant seed germination test results confirmed that all test samples achieved maximumgermination.This indicates there were no toxic residues,suggesting that the degraded materials are environmentally safe.Overall,this study contributes to the understanding of biodegradation mechanisms and the ecological impact of bio-based polymer composites as eco-friendly materials and products.
文摘Use of synthetic pesticides to manage crop pests has had a toll on human health, environmental safety and farmer’s income creating a need for alternative crop protection strategies. Botanical pesticides have been reported to be effective in managing crop pests, and a number of them have been formulated and commercialized. This study was conducted in North-Eastern Tanzania to establish the pesticidal and medicinal value of turmeric (Curcuma longa) and ginger (Zingiber officinale). Purposive sampling was adopted to select and interview 167 respondents drawn from farmers, traders, pharmaceutical shops, agro-shop operators and consumers of turmeric and ginger. Ginger and turmeric rhizomes were also collected for extraction, antifungal assay and biochemical analysis. Results showed that majority of the respondents were aware of the medicinal value of ginger and turmeric, with 59.5% having used the plants to treat respiratory related infections and healing skin surface and internal wounds. About 14% of farmers were aware of and had used aqueous botanical preparations from neem, moringa and Tephrosia to manage insect pests. Only 2.7% of farmers had used ginger powder as a protective insecticide on stored grains. Ginger and turmeric rhizome extracts showed high antifungal activity against Pythium (83% - 95%), Fusarium oxysporum f. sp. lycopersici (34% - 52%) and Alternaria solani (38% - 53%). A GC-MS analysis of ginger and turmeric extracts showed presence of α-zingiberene, β-sesquiphellandrene, α-farnesene, ar-curcumene, α-copaene, ar-tumerone and curlone. This study recommends that ginger and turmeric extracts be considered for development of a botanical pesticide and especially for management of damping off diseases.
文摘1.Introduction As global temperatures increase and weather patterns grow more er-ratic,the urgency of adopting climate-smart conservation strategies has intensified(Manyakaidze et al.,2024).Climate-smart conservation com-prises adaptive management practices aimed at bolstering the resilience of ecosystems and species amid climate variability(Birchall et al.,2021;Gabriel-Campos et al.,2021).
文摘The pathogenesis of insulin resistance is influenced by environmental factors,genetic predispositions,and several medications.Various drugs used to managemultiple ailments have been shown to induce insulin resistance,which could lead to Type II Diabetes mellitus(T2DM).Central to drug-induced insulin resistance is mitochondrial dysfunction.Amongst disturbed pathways in drug-inducedmitochondrial toxicity is mitophagy,a process that removes dysfunctionalmitochondria through the lysosomal pathways to maintain mitochondrial quality.A balancemust always be maintained between mitochondrial dynamics and mitophagy,as any alterations may contribute to the pathogenesis of metabolic diseases such as diabetes mellitus.If damaged mitochondria are not removed,their accumulation leads to increased production of reactive oxygen species(ROS)and release of calcium and cytochrome C,which leads to apoptosis.This review paper focuses on the implications of the mitophagy initiation pathways,such as Adenosine Monophosphate-activated Protein Kinase/Mammalian Target of Rapamycin(AMPK/mTOR),PTEN-induced kinase 1,and Parkin RBR E3 ubiquitin-protein ligase,PINK/Parkin,and the receptor-mediated pathways,such as FUN14 domain containing 1(FUNDC1)and Bcl-2 interacting protein 3(BNIP3/NIX),as a crucial link between drug-induced mitochondrial dysfunction and insulin sensitivity impairment.It also focuses on the implications of mitochondrial dynamics in drug-induced insulin impairments.Pharmacological agents such as simvastatin,clarithromycin,olanzapine,and dexamethasone have been investigated and shown to induce insulin resistance in part through altered mitochondrial function.In this review paper,we further illuminate disturbances in mitophagy and mitochondrial dynamics that could also be pivotal in insulin resistance development as a result of exposure to these drugs.Mitophagy and mitochondrial dynamics remain understudied.Exploring the implications of mitophagy pathways and mitochondrial dynamics on drug-induced insulin resistance could lead to the development of new approaches that can be used to mitigate insulin resistance associated with different classes of pharmacological modalities.
文摘The Agulhas Current is a major western boundary current flowing polewards on the southeast coast of South Africa.This analysis assesses its characteristics and suitability to generate power as a source of clean renewable energy.On a section of coastline some 400 km long,over a period spanning more than 5 years an extensive set of current measurements was obtained.These data confirmed that south-westward currents with a speed greater than 1.2 m s^(-1)occurred over more than 60%of the recorded time;such ocean current speeds compare very favourably to winds required for energy generation.These currents occurred at the continental shelf break in water depths around 100 m,in the upper 50 m of the water column.Occasional current slowdowns and reversals did occur,with the major influence coming from‘Natal Pulses’,which are large-scale meanders in the Current that temporarily reversed the currents at the measurement sites.However,because of the surface temperature structure of the relevant water masses,such meanders can be identified in satellite imagery giving a few days advance warning of such current reversals.The characteristics of western boundary currents have been known for many years,but at Present,there is no operational system where this source of power is being utilised.It has tremendous potential for renewable energy generation,but is symptomatic of the many engineering challenges that still have to be solved to make such generation economically viable.
基金financially supported by the National Natural Science Foundation of China(Nos.U23A20589 and E52307038)China Postdoctoral Science Foundation(No.2023M743622)+3 种基金Zhejiang Provincial Natural Science Foundation of China(No.LQ23E030006)Ningbo 2025 Key Scientific Research Programs(Nos.2022Z111,2022Z160,and 2022Z198)Natural Science Foundation of Ningbo City(Nos.2022J302 and 2024J122)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2021R01005)。
文摘Effective antifouling coatings are critical for protecting marine infrastructure from biofouling and environmental degradation;however,achieving long-term antifouling performance along with environmental stability remains a major challenge.In this study,a multifunctional bio-based epoxy coating is developed by integrating a dual-action antifouling system.Cinnamic acid(CA),which is known for its antibacterial and UV-shielding properties,was chemically grafted into ethylene glycol diglycidyl ether(EGDE)to provide intrinsic antifouling and anti-UV functions.Simultaneously,the KH560-modified silica aerogel was incorporated to create a dense hydrophobic surface that repels microorganism adhesion.The resulting coating exhibited a superhydrophobic contact angle of 154.3°,an ultralow surface energy,and exceptional resistance to protein and algal adhesion.Additionally,it achieves 99%bactericidal efficiency against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)while maintaining high transparency and ease of processing.These results highlight a promising strategy for designing durable and ecofriendly antifouling coatings suitable for demanding marine environments.
文摘The prevailing consensus in statistical literature is that multiple imputation is generally the most suitable method for addressing missing data in statistical analyses,whereas a complete case analysis is deemed appropriate only when the rate of missingness is negligible or when the missingness mechanism is missing completely at random(MCAR).This study investigates the applicability of this consensus within the context of supervised machine learning,with particular emphasis on the interactions between the imputation method,missingness mechanism,and missingness rate.Furthermore,we examine the time efficiency of these“state-of-the-art”imputation methods considering the time-sensitive nature of certain machine learning applications.Utilizing ten real-world datasets,we introduced missingness at rates ranging from approximately 5%–75%under the MCAR,missing at random(MAR),and missing not at random(MNAR)mechanisms.We subsequently address missing data using five methods:complete case analysis(CCA),mean imputation,hot deck imputation,regression imputation,and multiple imputation(MI).Statistical tests are conducted on the machine learning outcomes,and the findings are presented and analyzed.Our investigation reveals that in nearly all scenarios,CCA performs comparably to MI,even with substantial levels of missingness under the MAR and MNAR conditions and with missingness in the output variable for regression problems.Under some conditions,CCA surpasses MI in terms of its performance.Thus,given the considerable computational demands associated with MI,the application of CCA is recommended within the broader context of supervised machine learning,particularly in big-data environments.
文摘Background:Congenital cardiac diseases(CCD)are common congenital birth defects that require high-risk surgery.Outcomes following congenital cardiac surgery in children living in high-income countries(HIC)have been documented,but little is known from the African continent.This study aimed to determine factors associated with perioperative mortality in patients who underwent congenital cardiac surgery at our institution.Methods:This retrospective,cross-sectional study was conducted at Charlotte Maxeke Johannesburg Academic Hospital over 12 years(2006–2017).A multivariable regression analysis was performed for the factors which had a p-value of 0.1 and less in the univariable regression analysis.A Cox regression analysis was performed for mortality over time.All hypothesis testing accepted a p-value of<0.05 as statistically signiffcant.Results:There was an 11%(188/1701)in-hospital mortality rate overall.Patients who had a median age of 0.33 years(interquartile range[IQR]0.13–1.25),weight of 5 kg(IQR 3.45–8.20),longer cardiopulmonary bypass(CPB)of 179 min(16.0–275.5)and aortic cross-clamp of 82.5 min(35–139)were at greater risk of in-hospital mortality.Palliative surgeries had the highest in-hospital mortality rate at 41%.Cardiopulmonary bypass time(p<0.001),ICU length of stay(p<0.001),aortic cross-clamp time(p=0.001)and days on the ventilator(p<0.001)were independently predictive of perioperative all-cause in-hospital mortality in a multivariable regression model.Current predictive scoring systems had inconsistent performance,with the STAT 2020 mortality score being predictive in a multivariable regression analysis(p=0.038)and the RACHS-2 score in a Cox regression analysis(p=0.002).Conclusions:Perioperative mortality following congenital cardiac surgery was higher in our study group compared to HICs.Future prospective studies are required to highlight the need to prioritise and invest in the declining services provided to children with CCD in South Africa’s public sector.
文摘The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications.Besides its biodegradability,PBS can be derived from petroleum and biobased monomers.At the same time,the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products.The processes and techniques presented herein,are based on the production of biobased succinic acid monomer to PBS.However,the counterpart biobased monomer 1,4-butanediol(1,4-BDO)production has not been commercially demonstrated.This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS,its copolymers,and composites with the view to improve molecular weight,thermal,and mechanical properties.It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical,thermal,stability and mechanical structural properties.Importantly,the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films,biomedical and drug release,fire retardants,and agricultural products.The structure-functional performance characteristics of these developments in the PBS,copolymers,and composites are highlighted to provide baseline insights for future developments in engineering the specific applications,and structural interface PBS composites with enhanced structure-functional performance properties.
基金financed as part of the project“Development of a methodology for instrumental base formation for analysis and modeling of the spatial socio-economic development of systems based on internal reserves in the context of digitalization”(FSEG-2023-0008).
文摘This study explores the determinants of impact on ecology in Northern Tanzania.By examining key socio-economic,institutional,and structural factors influencing engagement the study provides insights in strengthening agribusiness networks and improving livelihoods.Data was collected from 215 farmers and 320 traders through a multistage sampling procedure.Heckman AI sample selection model was used in data analysis whereby the findings showed key factors influencing farmers’decisions on ecology were gender and years of formal education at p<0.1,and access to finance and off-farm income at p<0.05.The degree of farmers participation in social groups was influenced by age,household size,off-farm income and business network at p<0.05,number of years in formal education and access to finance at p<0.01,and distance to the market at p<0.1.The decision of traders to impact on ecology was significantly influenced by age and trading experience at p<0.1.Meanwhile,the degree of their involvement in social groups was strongly affected by gender,formal education,and trust at p<0.01,as well as by access to finance and business networks at p<0.05.The study concluded that natural ecology is influenced by socio economic and structural factors but trust among group members determine the degree of participation.The study recommends that strategies to improve agribusiness networks should understand underlying causes of impact on ecology and strengthen available social groups to improve performance of farmers and traders.
