Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry so...Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry sources.Polyvinyl alcohol(PVA)served as a toughening agent,whereas walnut shell powder(WSP)functioned as a filler in the formulation of a thermosetting bio-based GC-PVA-WSP(GCPW)composite with GC resin.The findings demonstrated that boric acid increased the limited oxygen index(LOI)value of GCPW to 33%,while simultaneously diminishing its total smoke production(TSP)by 99.9%,and achieving a flame retardant index(FRI)of 5.04.In addition,the incorporation of WSP enhanced the compressive strength of the GCPW composite to 9.15 MPa.Concurrently,the GCPW composite demonstrates excellent hydrophobic properties,with a thermal conductivity as low as 0.086 W/m·K.展开更多
Rapid and accurate detection of infectious virus particles, not just viral nucleic acid, is essential to avoid unnecessary quarantine and effectively control the spread of viral diseases such as coronavirus disease 20...Rapid and accurate detection of infectious virus particles, not just viral nucleic acid, is essential to avoid unnecessary quarantine and effectively control the spread of viral diseases such as coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). Real-time quantitative polymerase chain reaction (RT-qPCR) was the most widely used detection technique during the COVID-19 outbreak. However, it cannot discriminate between intact infectious viruses and surface-distorted, non-infectious virus particles or naked viral RNA. In this study, we present a strategy for the specific detection of infectious coronaviruses by combining viral receptor capture and reverse transcription loop-mediated isothermal amplification (RT-LAMP). We successfully applied this strategy to detect infectious virus particles of the SARS-CoV-2 surrogate virus and the human coronavirus NL63 (HCoV-NL63). Virus particles were first captured on ELISA plates coated with the recombinant human angiotensin-converting enzyme 2 (hACE2) receptor. Viral RNA was then extracted from the particles and detected by RT-LAMP using virus-specific primers. In our experimental setting, the proposed method had a minimum detection limit (LOD) of 90 PFU/mL, sensitivity of 96.2%, and specificity of 100%. Our study provides a proof-of-concept that viral receptor capture combined with RT-LAMP can differentiate infectious coronaviruses from non-infectious virions or naked viral RNA. This paves the way for this virus detection strategy to become a mainstream tool for the management, prevention and control of epidemic coronavirus diseases.展开更多
Indonesia,with its vast forested regions,has experienced significant deforestation,adversely affecting the wood industry.As a result,alternative sources of lignocellulosic biomass are required to mitigate this impact....Indonesia,with its vast forested regions,has experienced significant deforestation,adversely affecting the wood industry.As a result,alternative sources of lignocellulosic biomass are required to mitigate this impact.Among the abundant lignocellulosic raw materials in Indonesia,particularly in Sumatra,bamboo stands out as a promising substitute.Bamboo is a highly versatile resource,suitable for various applications,including its use as a composite raw material to replace traditional wood-based products.This research work aimed to investigate and evaluate the characteristics—morphology,anatomy,physical and mechanical properties,chemical composition,starch content,and natural resistance—of three bamboo species:hitam bamboo(Gigantochloa atroviolacea),betung bamboo(Dendrocalamus asper),and belangke bamboo(Gigantochloa pruriens),as well as their suitability for the production of oriented strand boards(OSB).The lumen values of the bamboo samples ranged between 10 and 15μm,with hitam and betung bamboo exhibitingmedium-thickness cell walls(>5μm).Based on fiber dimension analysis,belangke,and betung bamboo are classified within quality class II,whereas hitam bamboo falls into class Ⅰ.The highest recorded tensile,shear,and compressive mechanical strength values were observed at the tips of hitam bamboo,measuring 563.43 MPa,15 MPa,and 6.87 kN/mm^(2),respectively.The bamboo samples underwent three different treatments:(1)immersion in water for 24 h,(2)autoclaving at 120℃ for 1 h,and(3)a control group with no treatment.OSB panels were produced with dimensions of 20 cm×20 cm×1 cm(length×width×thickness)using isocyanate adhesive and conditioned for 14 days.The physical and mechanical properties of the OSBs were evaluated based on the Japan Industrial Standard(JIS)A5908:2003 and theCanadian StandardsAssociation(CSA)0437.0:2011 criteria.The density of the laboratory-produced OSB panels ranged from 0.60 to 0.73 g/cm^(3),moisture content varied from5.4% to 8.1%,water absorption ranged between 31.6% and 45.8%,and thickness swelling was recorded at 5.1% to 16.3%.The modulus of elasticity(MOE)ranged from2745.1 to 7813.3 MPa,themodulus of rupture(MOR)from 30.8 to 58.8MPa,and internal bonding(IB)from 0.27 to 0.47 MPa.Overall,all OSB panels produced in this study met the specifications outlined in JIS A 5908(2003)and CSA 0437.0(2011),demonstrating the viability of these bamboo species as raw materials for OSB production.展开更多
Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics ...Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.展开更多
The utilisation of sugar palm bunches-charcoal briquettes(SPB-CB)represents a significant advancement in biomass energy.This study aimed to analyse the properties of charcoal briquettes produced from SPB(Arenga longip...The utilisation of sugar palm bunches-charcoal briquettes(SPB-CB)represents a significant advancement in biomass energy.This study aimed to analyse the properties of charcoal briquettes produced from SPB(Arenga longipes).The experiment involved categorising the dimensions of charcoal powder into three specific particle sizes:20-40 mesh,40-60 mesh,and particles that could pass through a 60-mesh screen.The charcoal powder will be combined with tapioca as a binding agent at three specific concentrations:11%,13%,and 15%.The research findings indicate that the samples underwent 60 mesh passes achieved the maximum briquette density,with an average value of 0.58 g/cm^(3).The highest attainable compressive strength sample value was 27.52 kgf/cm^(2),which was attained by employing 60 mesh size and 15%adhesive concentration.The calorimetric investigation showed that SPB-charcoal had the highest calorific value of 25.88 MJ/kg,while the SPB-CB had a little lower caloric value of 24.64 MJ/kg.The ash content and volatile matter values showed that the briquettes with the lowest ash content had values of 10.49%and 32.65%,respectively.Furthermore,the carbon fixation values varied between 16.65%and 52.36%.Thermogravimetric analysis indicates that charcoal derived from SPB exhibits superior thermal characteristics compared to charcoal briquettes.However,thermal properties of SPB charcoal do not show significant differences when compared to charcoal briquettes that have been processed with a mesh size of 20-40 and include 11%adhesive.According to this research,it may be inferred that charcoal briquettes made from sugar palm bunches meet the requirements specified in SNI 01-6235-2000.展开更多
A comparative study of the structure and fractal properties of arrays of the silver nano-/micro-particles deposited on the silicon substrate both from the aerosol and fog showed that the form of the silver individual ...A comparative study of the structure and fractal properties of arrays of the silver nano-/micro-particles deposited on the silicon substrate both from the aerosol and fog showed that the form of the silver individual particles and nano-/microstructures greatly depends on the deposition conditions. By passing an aerosol through isopropyl alcohol, the formation of fractal aggregates of the silver nano-/micro-particles both in the air and in alcohol was observed. Deposition of the silver nano-/micro-particles in the atmosphere of the saturated isopropyl alcohol vapours led to formation of fog. Microdroplets of the silver colloidal solution were deposited on the substrate. The further evaporation of alcohol created the silver nano/microstructures in the form of annular layers. It was found that the concerned annular layers contained silver particles of the same shape in the form of a Crescent (or Janus-nano-/microparticles). The nature of discovered effects is discussed.展开更多
A group of variously colored proteins belonging to the green fAuorescent protein(GFP)family are responsible for coloring coral tissues.Corals of the Great Barrier Reef were studied with the custom-built fiber laser fl...A group of variously colored proteins belonging to the green fAuorescent protein(GFP)family are responsible for coloring coral tissues.Corals of the Great Barrier Reef were studied with the custom-built fiber laser fluorescence spectrometers.Spectral analysis showed that most of the excarmined corals contained multiple fuorescent peaks ranging from 470 to 620nm.This obser-vation was attributed to the presence of multiple genes of GFP-like proteins in a single coral,as well as by the photo-induced post-translational modifcations of certain GFP-like proteins.We isolated a novel photo-convertible fuorescent protein(FP)from one of the tested corals.We:propose that two processes may explain the observed diversity of the fuorescent spectra in corals:(1)dark post-translational modifcation(maturation),and(2)color photo-conversion of certain maturated proteins in response to sunlight.展开更多
Thymidine glycol (5,6-dihydroxy-5,6-dihydrothymidine, Tg) is a major type of oxidative damage in DNA. During chemical oligonucleotide synthesis, Tg residue was incorporated in the different positions of 17 b.p. DNA du...Thymidine glycol (5,6-dihydroxy-5,6-dihydrothymidine, Tg) is a major type of oxidative damage in DNA. During chemical oligonucleotide synthesis, Tg residue was incorporated in the different positions of 17 b.p. DNA duplexes, which differ in one base pair in the internal part. According to UV-melting curves, Tg destabilizes the double helix in a sequence independent manner. In contrast, the localized alterations in duplex structure were shown by CD spectroscopy to depend on the type of base pairs flanking the Tg lesion. Molecular dynamics simulations demonstrate that Tg is partially out of the double helix. For the first time, Tg impact on several site-specific DNA-binding proteins is studied, namely p50 and p65 subunits of nuclear factor kappa-B (NF-κB) and DNA methyltransferase SsoII (M.SsoII). Our results show that p50/p50 and p65/p65 homodimers of NF-κB can tolerate a single Tg residue in the binding site quite well. Nevertheless the homodimers have different affinities to the oxidized κB site depending on the Tg position. M.SsoII can act as a transcription repressor when bound to the regulatory site. M.SsoII demonstrates decreased affinity and lowered methylation efficiency when its methylation site contains Tg in the central position. Single Tg in one half of the regulatory site decreases M.SsoII affinity to the oxidized DNA, whereas Tg presence in both half-sites prevents M.SsoII binding to such ligand.展开更多
In response to the growing environmental threat posed by plastic waste,this study developed hydrophobic biopolymer films from red seaweed(Kappaphycus alvarezii)as a sustainable alternative for packaging.The films were...In response to the growing environmental threat posed by plastic waste,this study developed hydrophobic biopolymer films from red seaweed(Kappaphycus alvarezii)as a sustainable alternative for packaging.The films were fabricated using a solvent-casting method,followed by surface treatment with triethoxymethylsilane to increase their hydrophobicity.Key metrics,including water solubility(reduced by 37.4%),moisture absorption capacity(decreased by 108.6%),and water vapor permeability(decreased by 65.4%),demonstrated significant improvements over untreated films.Fourier transform infrared(FT-IR)spectroscopy confirmed successful silane integration,whereas mechanical testing revealed increased tensile strength(up to 24.44 MPa)and Young’s modulus(183.41 MPa),with a moderate reduction in elongation at break.These findings indicate that silane-modified seaweed biopolymer films have strong potential as eco-friendly packaging solutions to mitigate plastic waste.展开更多
The tribe Delphineae,comprising two genera,Aconitum L.and Delphinium L.,is the richest source of bioactive diterpenoid alkaloids(DAs),while their highly similar chemical structures create a major challenge for derepli...The tribe Delphineae,comprising two genera,Aconitum L.and Delphinium L.,is the richest source of bioactive diterpenoid alkaloids(DAs),while their highly similar chemical structures create a major challenge for dereplication from complex mixture.To solve the inefficient discovery process of natural DAs,a novel dereplication strategy based on pattern recognition of specific heteronuclear multiple bond correlation(HMBC)signals has been established in this study.This strategy utilized the diagnostic signals in the HMBC spectra of C_(19)-DAs,which could indicate the structural categories.The newly designed software MatchNat allowed in silico recognition of C_(19)-DA types.The developed dereplication system was demonstrated to be a practical strategy to dereplicate a variety of natural products from two Delphineae plants,including Aconitum vilmorinianum Kom.and Delphinium pachycentrum Hemsl.Known compounds could be rapidly recognized from the mixture,and novel DAs were found with the aid of MatchNat.Consequently,targeted isolation led to the explosive discovery of a series of novel DAs.This dereplication system has the potential to be adopted for dereplication of any other class of natural products and has shown promising application as a complementary tool in the nuclear magnetic resonance analysis of traditional Chinese medicines.展开更多
基金supported by the Natural Science Foundation of China(32460363)Yunnan Province Agricultural Joint Key Foundation(No.202401BD070001-029)+3 种基金Yunnan Agricultural Joint General Foundation(202101BD070001-105)the Yunnan Provincial Youth Top Talent Project(Grant No.YNWR-QNBJ-2020-166)the Foreign ExpertWorkstation(202305AF150006)the 111 Project(D21027).
文摘Highly flame-retardant bio-based composites were prepared in this study.Firstly,glucose-citric acid(GC)resin was synthesized through the interaction of glucose and citric acid derived from agricultural and forestry sources.Polyvinyl alcohol(PVA)served as a toughening agent,whereas walnut shell powder(WSP)functioned as a filler in the formulation of a thermosetting bio-based GC-PVA-WSP(GCPW)composite with GC resin.The findings demonstrated that boric acid increased the limited oxygen index(LOI)value of GCPW to 33%,while simultaneously diminishing its total smoke production(TSP)by 99.9%,and achieving a flame retardant index(FRI)of 5.04.In addition,the incorporation of WSP enhanced the compressive strength of the GCPW composite to 9.15 MPa.Concurrently,the GCPW composite demonstrates excellent hydrophobic properties,with a thermal conductivity as low as 0.086 W/m·K.
基金supported by the National Natural Science Foundation of China(32470160)the National Key Research and Development Program of China(2021YFC2300100,GZNL2023A01008)+2 种基金the Shenzhen Science and Technology Program(#JSGG20200225150431472,JSGG20210901145403012,and JSGG20220301090005007)the“Pearl River Talent Plan”Innovation and Entrepreneurship Team Project of Guangdong Province(2016LJ06Y540 and 2019ZT08Y464)the Science and Technology Program of Guangdong Province,China(2021B1212040017).
文摘Rapid and accurate detection of infectious virus particles, not just viral nucleic acid, is essential to avoid unnecessary quarantine and effectively control the spread of viral diseases such as coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). Real-time quantitative polymerase chain reaction (RT-qPCR) was the most widely used detection technique during the COVID-19 outbreak. However, it cannot discriminate between intact infectious viruses and surface-distorted, non-infectious virus particles or naked viral RNA. In this study, we present a strategy for the specific detection of infectious coronaviruses by combining viral receptor capture and reverse transcription loop-mediated isothermal amplification (RT-LAMP). We successfully applied this strategy to detect infectious virus particles of the SARS-CoV-2 surrogate virus and the human coronavirus NL63 (HCoV-NL63). Virus particles were first captured on ELISA plates coated with the recombinant human angiotensin-converting enzyme 2 (hACE2) receptor. Viral RNA was then extracted from the particles and detected by RT-LAMP using virus-specific primers. In our experimental setting, the proposed method had a minimum detection limit (LOD) of 90 PFU/mL, sensitivity of 96.2%, and specificity of 100%. Our study provides a proof-of-concept that viral receptor capture combined with RT-LAMP can differentiate infectious coronaviruses from non-infectious virions or naked viral RNA. This paves the way for this virus detection strategy to become a mainstream tool for the management, prevention and control of epidemic coronavirus diseases.
基金supported by the TALENTA research grant scheme of the“Kolaborasi Nasional Penerima Dana Hibah WCU(World Class University)Universitas Sumatera Utara”in the year 2022(Number:353/UN5.2.3.1/PPM/KP-TALENTA/2022)supported by the project“Development,Exploitation Properties and Application of Eco-Friendly Wood-Based Composites from Alternative Lignocellulosic Raw Materials”,Project No.HHC-b-1290/19.10.2023,carried out at the University of Forestry,Sofia,Bulgaria.
文摘Indonesia,with its vast forested regions,has experienced significant deforestation,adversely affecting the wood industry.As a result,alternative sources of lignocellulosic biomass are required to mitigate this impact.Among the abundant lignocellulosic raw materials in Indonesia,particularly in Sumatra,bamboo stands out as a promising substitute.Bamboo is a highly versatile resource,suitable for various applications,including its use as a composite raw material to replace traditional wood-based products.This research work aimed to investigate and evaluate the characteristics—morphology,anatomy,physical and mechanical properties,chemical composition,starch content,and natural resistance—of three bamboo species:hitam bamboo(Gigantochloa atroviolacea),betung bamboo(Dendrocalamus asper),and belangke bamboo(Gigantochloa pruriens),as well as their suitability for the production of oriented strand boards(OSB).The lumen values of the bamboo samples ranged between 10 and 15μm,with hitam and betung bamboo exhibitingmedium-thickness cell walls(>5μm).Based on fiber dimension analysis,belangke,and betung bamboo are classified within quality class II,whereas hitam bamboo falls into class Ⅰ.The highest recorded tensile,shear,and compressive mechanical strength values were observed at the tips of hitam bamboo,measuring 563.43 MPa,15 MPa,and 6.87 kN/mm^(2),respectively.The bamboo samples underwent three different treatments:(1)immersion in water for 24 h,(2)autoclaving at 120℃ for 1 h,and(3)a control group with no treatment.OSB panels were produced with dimensions of 20 cm×20 cm×1 cm(length×width×thickness)using isocyanate adhesive and conditioned for 14 days.The physical and mechanical properties of the OSBs were evaluated based on the Japan Industrial Standard(JIS)A5908:2003 and theCanadian StandardsAssociation(CSA)0437.0:2011 criteria.The density of the laboratory-produced OSB panels ranged from 0.60 to 0.73 g/cm^(3),moisture content varied from5.4% to 8.1%,water absorption ranged between 31.6% and 45.8%,and thickness swelling was recorded at 5.1% to 16.3%.The modulus of elasticity(MOE)ranged from2745.1 to 7813.3 MPa,themodulus of rupture(MOR)from 30.8 to 58.8MPa,and internal bonding(IB)from 0.27 to 0.47 MPa.Overall,all OSB panels produced in this study met the specifications outlined in JIS A 5908(2003)and CSA 0437.0(2011),demonstrating the viability of these bamboo species as raw materials for OSB production.
基金funded by the Equity Project Universitas Sumatera Utara(Number:10/UN5.2.3.1/PPM/KPEP/2023),which is entitled Pengembangan Papan Partikel Tahan Api Rendah Emisi Berbahan Limbah Tanaman Mangrove dan Limbah Tanaman Pertanian Melalui Penambahan Lignin Terfosforilasi Sebagai Filler.PT Greenei Alam Indonesia(PT GAI)contributed to providing the areca leaf sheath through the implementation of a collaboration agreement with the Research Center for Biomass and Bioproducts BRIN FY 2023-2025.
文摘Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.
基金funded by the Regular Fundamental Research Grant of the Directorate of Research,Technology,and Community Service,Ministry of Education,Culture,Research,and Technology,Republic of Indonesia No.093/E5/PG.02.00.PL/2024Research Institution of Universitas Sumatera Utara No.1/UN5.4.10S/PPM/KPDRTPM/2024supported by the project“Development,Exploitation Properties and Application of Eco-Friendly Wood-Based Composites from Alternative Lignocellulosic Raw Materials”,Project No.HN C--1290/19.10.2023,carried out at the University of Forestry,Sofia,Bulgaria.
文摘The utilisation of sugar palm bunches-charcoal briquettes(SPB-CB)represents a significant advancement in biomass energy.This study aimed to analyse the properties of charcoal briquettes produced from SPB(Arenga longipes).The experiment involved categorising the dimensions of charcoal powder into three specific particle sizes:20-40 mesh,40-60 mesh,and particles that could pass through a 60-mesh screen.The charcoal powder will be combined with tapioca as a binding agent at three specific concentrations:11%,13%,and 15%.The research findings indicate that the samples underwent 60 mesh passes achieved the maximum briquette density,with an average value of 0.58 g/cm^(3).The highest attainable compressive strength sample value was 27.52 kgf/cm^(2),which was attained by employing 60 mesh size and 15%adhesive concentration.The calorimetric investigation showed that SPB-charcoal had the highest calorific value of 25.88 MJ/kg,while the SPB-CB had a little lower caloric value of 24.64 MJ/kg.The ash content and volatile matter values showed that the briquettes with the lowest ash content had values of 10.49%and 32.65%,respectively.Furthermore,the carbon fixation values varied between 16.65%and 52.36%.Thermogravimetric analysis indicates that charcoal derived from SPB exhibits superior thermal characteristics compared to charcoal briquettes.However,thermal properties of SPB charcoal do not show significant differences when compared to charcoal briquettes that have been processed with a mesh size of 20-40 and include 11%adhesive.According to this research,it may be inferred that charcoal briquettes made from sugar palm bunches meet the requirements specified in SNI 01-6235-2000.
文摘A comparative study of the structure and fractal properties of arrays of the silver nano-/micro-particles deposited on the silicon substrate both from the aerosol and fog showed that the form of the silver individual particles and nano-/microstructures greatly depends on the deposition conditions. By passing an aerosol through isopropyl alcohol, the formation of fractal aggregates of the silver nano-/micro-particles both in the air and in alcohol was observed. Deposition of the silver nano-/micro-particles in the atmosphere of the saturated isopropyl alcohol vapours led to formation of fog. Microdroplets of the silver colloidal solution were deposited on the substrate. The further evaporation of alcohol created the silver nano/microstructures in the form of annular layers. It was found that the concerned annular layers contained silver particles of the same shape in the form of a Crescent (or Janus-nano-/microparticles). The nature of discovered effects is discussed.
基金RAS presidium grant "Molecular cellular biology",RFBR 06-02-02100,RFBR CCDFR 13-00-40303.
文摘A group of variously colored proteins belonging to the green fAuorescent protein(GFP)family are responsible for coloring coral tissues.Corals of the Great Barrier Reef were studied with the custom-built fiber laser fluorescence spectrometers.Spectral analysis showed that most of the excarmined corals contained multiple fuorescent peaks ranging from 470 to 620nm.This obser-vation was attributed to the presence of multiple genes of GFP-like proteins in a single coral,as well as by the photo-induced post-translational modifcations of certain GFP-like proteins.We isolated a novel photo-convertible fuorescent protein(FP)from one of the tested corals.We:propose that two processes may explain the observed diversity of the fuorescent spectra in corals:(1)dark post-translational modifcation(maturation),and(2)color photo-conversion of certain maturated proteins in response to sunlight.
文摘Thymidine glycol (5,6-dihydroxy-5,6-dihydrothymidine, Tg) is a major type of oxidative damage in DNA. During chemical oligonucleotide synthesis, Tg residue was incorporated in the different positions of 17 b.p. DNA duplexes, which differ in one base pair in the internal part. According to UV-melting curves, Tg destabilizes the double helix in a sequence independent manner. In contrast, the localized alterations in duplex structure were shown by CD spectroscopy to depend on the type of base pairs flanking the Tg lesion. Molecular dynamics simulations demonstrate that Tg is partially out of the double helix. For the first time, Tg impact on several site-specific DNA-binding proteins is studied, namely p50 and p65 subunits of nuclear factor kappa-B (NF-κB) and DNA methyltransferase SsoII (M.SsoII). Our results show that p50/p50 and p65/p65 homodimers of NF-κB can tolerate a single Tg residue in the binding site quite well. Nevertheless the homodimers have different affinities to the oxidized κB site depending on the Tg position. M.SsoII can act as a transcription repressor when bound to the regulatory site. M.SsoII demonstrates decreased affinity and lowered methylation efficiency when its methylation site contains Tg in the central position. Single Tg in one half of the regulatory site decreases M.SsoII affinity to the oxidized DNA, whereas Tg presence in both half-sites prevents M.SsoII binding to such ligand.
文摘In response to the growing environmental threat posed by plastic waste,this study developed hydrophobic biopolymer films from red seaweed(Kappaphycus alvarezii)as a sustainable alternative for packaging.The films were fabricated using a solvent-casting method,followed by surface treatment with triethoxymethylsilane to increase their hydrophobicity.Key metrics,including water solubility(reduced by 37.4%),moisture absorption capacity(decreased by 108.6%),and water vapor permeability(decreased by 65.4%),demonstrated significant improvements over untreated films.Fourier transform infrared(FT-IR)spectroscopy confirmed successful silane integration,whereas mechanical testing revealed increased tensile strength(up to 24.44 MPa)and Young’s modulus(183.41 MPa),with a moderate reduction in elongation at break.These findings indicate that silane-modified seaweed biopolymer films have strong potential as eco-friendly packaging solutions to mitigate plastic waste.
基金funded by the Science and Technology Development Fund,Macao SAR(File Nos.0023/2019/AKP,0077/2019/A2,0002/2019/APD,and 0040/2021/AGJ)the National Natural Science Foundation of China(No.31860095)。
文摘The tribe Delphineae,comprising two genera,Aconitum L.and Delphinium L.,is the richest source of bioactive diterpenoid alkaloids(DAs),while their highly similar chemical structures create a major challenge for dereplication from complex mixture.To solve the inefficient discovery process of natural DAs,a novel dereplication strategy based on pattern recognition of specific heteronuclear multiple bond correlation(HMBC)signals has been established in this study.This strategy utilized the diagnostic signals in the HMBC spectra of C_(19)-DAs,which could indicate the structural categories.The newly designed software MatchNat allowed in silico recognition of C_(19)-DA types.The developed dereplication system was demonstrated to be a practical strategy to dereplicate a variety of natural products from two Delphineae plants,including Aconitum vilmorinianum Kom.and Delphinium pachycentrum Hemsl.Known compounds could be rapidly recognized from the mixture,and novel DAs were found with the aid of MatchNat.Consequently,targeted isolation led to the explosive discovery of a series of novel DAs.This dereplication system has the potential to be adopted for dereplication of any other class of natural products and has shown promising application as a complementary tool in the nuclear magnetic resonance analysis of traditional Chinese medicines.
